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Sample records for statistic isotonic bivariate

  1. The bivariate statistical analysis of environmental (compositional) data.

    Science.gov (United States)

    Filzmoser, Peter; Hron, Karel; Reimann, Clemens

    2010-09-01

    Environmental sciences usually deal with compositional (closed) data. Whenever the concentration of chemical elements is measured, the data will be closed, i.e. the relevant information is contained in the ratios between the variables rather than in the data values reported for the variables. Data closure has severe consequences for statistical data analysis. Most classical statistical methods are based on the usual Euclidean geometry - compositional data, however, do not plot into Euclidean space because they have their own geometry which is not linear but curved in the Euclidean sense. This has severe consequences for bivariate statistical analysis: correlation coefficients computed in the traditional way are likely to be misleading, and the information contained in scatterplots must be used and interpreted differently from sets of non-compositional data. As a solution, the ilr transformation applied to a variable pair can be used to display the relationship and to compute a measure of stability. This paper discusses how this measure is related to the usual correlation coefficient and how it can be used and interpreted. Moreover, recommendations are provided for how the scatterplot can still be used, and which alternatives exist for displaying the relationship between two variables. Copyright 2010 Elsevier B.V. All rights reserved.

  2. GIS-based bivariate statistical techniques for groundwater potential ...

    Indian Academy of Sciences (India)

    Ali Haghizadeh

    2017-11-23

    % and 23.74% of the study area is covered by ... Groundwater; statistical index; Dempster–Shafer theory; water resource management; GIS. 1. Introduction ... Positioning System (GPS), and Remote Sensing. (RS) (Srivastava ...

  3. INLAND DISSOLVED SALT CHEMISTRY: STATISTICAL EVALUATION OF BIVARIATE AND TERNARY DIAGRAM MODELS FOR SURFACE AND SUBSURFACE WATERS

    Science.gov (United States)

    We compared the use of ternary and bivariate diagrams to distinguish the effects of atmospheric precipitation, rock weathering, and evaporation on inland surface and subsurface water chemistry. The three processes could not be statistically differentiated using bivariate models e...

  4. Parameter estimation and statistical test of geographically weighted bivariate Poisson inverse Gaussian regression models

    Science.gov (United States)

    Amalia, Junita; Purhadi, Otok, Bambang Widjanarko

    2017-11-01

    Poisson distribution is a discrete distribution with count data as the random variables and it has one parameter defines both mean and variance. Poisson regression assumes mean and variance should be same (equidispersion). Nonetheless, some case of the count data unsatisfied this assumption because variance exceeds mean (over-dispersion). The ignorance of over-dispersion causes underestimates in standard error. Furthermore, it causes incorrect decision in the statistical test. Previously, paired count data has a correlation and it has bivariate Poisson distribution. If there is over-dispersion, modeling paired count data is not sufficient with simple bivariate Poisson regression. Bivariate Poisson Inverse Gaussian Regression (BPIGR) model is mix Poisson regression for modeling paired count data within over-dispersion. BPIGR model produces a global model for all locations. In another hand, each location has different geographic conditions, social, cultural and economic so that Geographically Weighted Regression (GWR) is needed. The weighting function of each location in GWR generates a different local model. Geographically Weighted Bivariate Poisson Inverse Gaussian Regression (GWBPIGR) model is used to solve over-dispersion and to generate local models. Parameter estimation of GWBPIGR model obtained by Maximum Likelihood Estimation (MLE) method. Meanwhile, hypothesis testing of GWBPIGR model acquired by Maximum Likelihood Ratio Test (MLRT) method.

  5. An integrated user-friendly ArcMAP tool for bivariate statistical modeling in geoscience applications

    Science.gov (United States)

    Jebur, M. N.; Pradhan, B.; Shafri, H. Z. M.; Yusof, Z.; Tehrany, M. S.

    2014-10-01

    Modeling and classification difficulties are fundamental issues in natural hazard assessment. A geographic information system (GIS) is a domain that requires users to use various tools to perform different types of spatial modeling. Bivariate statistical analysis (BSA) assists in hazard modeling. To perform this analysis, several calculations are required and the user has to transfer data from one format to another. Most researchers perform these calculations manually by using Microsoft Excel or other programs. This process is time consuming and carries a degree of uncertainty. The lack of proper tools to implement BSA in a GIS environment prompted this study. In this paper, a user-friendly tool, BSM (bivariate statistical modeler), for BSA technique is proposed. Three popular BSA techniques such as frequency ratio, weights-of-evidence, and evidential belief function models are applied in the newly proposed ArcMAP tool. This tool is programmed in Python and is created by a simple graphical user interface, which facilitates the improvement of model performance. The proposed tool implements BSA automatically, thus allowing numerous variables to be examined. To validate the capability and accuracy of this program, a pilot test area in Malaysia is selected and all three models are tested by using the proposed program. Area under curve is used to measure the success rate and prediction rate. Results demonstrate that the proposed program executes BSA with reasonable accuracy. The proposed BSA tool can be used in numerous applications, such as natural hazard, mineral potential, hydrological, and other engineering and environmental applications.

  6. An integrated user-friendly ArcMAP tool for bivariate statistical modelling in geoscience applications

    Science.gov (United States)

    Jebur, M. N.; Pradhan, B.; Shafri, H. Z. M.; Yusoff, Z. M.; Tehrany, M. S.

    2015-03-01

    Modelling and classification difficulties are fundamental issues in natural hazard assessment. A geographic information system (GIS) is a domain that requires users to use various tools to perform different types of spatial modelling. Bivariate statistical analysis (BSA) assists in hazard modelling. To perform this analysis, several calculations are required and the user has to transfer data from one format to another. Most researchers perform these calculations manually by using Microsoft Excel or other programs. This process is time-consuming and carries a degree of uncertainty. The lack of proper tools to implement BSA in a GIS environment prompted this study. In this paper, a user-friendly tool, bivariate statistical modeler (BSM), for BSA technique is proposed. Three popular BSA techniques, such as frequency ratio, weight-of-evidence (WoE), and evidential belief function (EBF) models, are applied in the newly proposed ArcMAP tool. This tool is programmed in Python and created by a simple graphical user interface (GUI), which facilitates the improvement of model performance. The proposed tool implements BSA automatically, thus allowing numerous variables to be examined. To validate the capability and accuracy of this program, a pilot test area in Malaysia is selected and all three models are tested by using the proposed program. Area under curve (AUC) is used to measure the success rate and prediction rate. Results demonstrate that the proposed program executes BSA with reasonable accuracy. The proposed BSA tool can be used in numerous applications, such as natural hazard, mineral potential, hydrological, and other engineering and environmental applications.

  7. GIS-based bivariate statistical techniques for groundwater potential analysis (an example of Iran)

    Science.gov (United States)

    Haghizadeh, Ali; Moghaddam, Davoud Davoudi; Pourghasemi, Hamid Reza

    2017-12-01

    Groundwater potential analysis prepares better comprehension of hydrological settings of different regions. This study shows the potency of two GIS-based data driven bivariate techniques namely statistical index (SI) and Dempster-Shafer theory (DST) to analyze groundwater potential in Broujerd region of Iran. The research was done using 11 groundwater conditioning factors and 496 spring positions. Based on the ground water potential maps (GPMs) of SI and DST methods, 24.22% and 23.74% of the study area is covered by poor zone of groundwater potential, and 43.93% and 36.3% of Broujerd region is covered by good and very good potential zones, respectively. The validation of outcomes displayed that area under the curve (AUC) of SI and DST techniques are 81.23% and 79.41%, respectively, which shows SI method has slightly a better performance than the DST technique. Therefore, SI and DST methods are advantageous to analyze groundwater capacity and scrutinize the complicated relation between groundwater occurrence and groundwater conditioning factors, which permits investigation of both systemic and stochastic uncertainty. Finally, it can be realized that these techniques are very beneficial for groundwater potential analyzing and can be practical for water-resource management experts.

  8. Inland dissolved salt chemistry: statistical evaluation of bivariate and ternary diagram models for surface and subsurface waters

    Directory of Open Access Journals (Sweden)

    Stephen T. THRELKELD

    2000-08-01

    Full Text Available We compared the use of ternary and bivariate diagrams to distinguish the effects of atmospheric precipitation, rock weathering, and evaporation on inland surface and subsurface water chemistry. The three processes could not be statistically differentiated using bivariate models even if large water bodies were evaluated separate from small water bodies. Atmospheric precipitation effects were identified using ternary diagrams in water with total dissolved salts (TDS 1000 mg l-1. A principal components analysis showed that the variability in the relative proportions of the major ions was related to atmospheric precipitation, weathering, and evaporation. About half of the variation in the distribution of inorganic ions was related to rock weathering. By considering most of the important inorganic ions, ternary diagrams are able to distinguish the contributions of atmospheric precipitation, rock weathering, and evaporation to inland water chemistry.

  9. The return period analysis of natural disasters with statistical modeling of bivariate joint probability distribution.

    Science.gov (United States)

    Li, Ning; Liu, Xueqin; Xie, Wei; Wu, Jidong; Zhang, Peng

    2013-01-01

    New features of natural disasters have been observed over the last several years. The factors that influence the disasters' formation mechanisms, regularity of occurrence and main characteristics have been revealed to be more complicated and diverse in nature than previously thought. As the uncertainty involved increases, the variables need to be examined further. This article discusses the importance and the shortage of multivariate analysis of natural disasters and presents a method to estimate the joint probability of the return periods and perform a risk analysis. Severe dust storms from 1990 to 2008 in Inner Mongolia were used as a case study to test this new methodology, as they are normal and recurring climatic phenomena on Earth. Based on the 79 investigated events and according to the dust storm definition with bivariate, the joint probability distribution of severe dust storms was established using the observed data of maximum wind speed and duration. The joint return periods of severe dust storms were calculated, and the relevant risk was analyzed according to the joint probability. The copula function is able to simulate severe dust storm disasters accurately. The joint return periods generated are closer to those observed in reality than the univariate return periods and thus have more value in severe dust storm disaster mitigation, strategy making, program design, and improvement of risk management. This research may prove useful in risk-based decision making. The exploration of multivariate analysis methods can also lay the foundation for further applications in natural disaster risk analysis. © 2012 Society for Risk Analysis.

  10. Bivariate discrete Linnik distribution

    Directory of Open Access Journals (Sweden)

    Davis Antony Mundassery

    2014-10-01

    Full Text Available Christoph and Schreiber (1998a studied the discrete analogue of positive Linnik distribution and obtained its characterizations using survival function. In this paper, we introduce a bivariate form of the discrete Linnik distribution and study its distributional properties. Characterizations of the bivariate distribution are obtained using compounding schemes. Autoregressive processes are developed with marginals follow the bivariate discrete Linnik distribution.

  11. Flash flood susceptibility analysis and its mapping using different bivariate models in Iran: a comparison between Shannon's entropy, statistical index, and weighting factor models.

    Science.gov (United States)

    Khosravi, Khabat; Pourghasemi, Hamid Reza; Chapi, Kamran; Bahri, Masoumeh

    2016-12-01

    Flooding is a very common worldwide natural hazard causing large-scale casualties every year; Iran is not immune to this thread as well. Comprehensive flood susceptibility mapping is very important to reduce losses of lives and properties. Thus, the aim of this study is to map susceptibility to flooding by different bivariate statistical methods including Shannon's entropy (SE), statistical index (SI), and weighting factor (Wf). In this regard, model performance evaluation is also carried out in Haraz Watershed, Mazandaran Province, Iran. In the first step, 211 flood locations were identified by the documentary sources and field inventories, of which 70% (151 positions) were used for flood susceptibility modeling and 30% (60 positions) for evaluation and verification of the model. In the second step, ten influential factors in flooding were chosen, namely slope angle, plan curvature, altitude, topographic wetness index (TWI), stream power index (SPI), distance from river, rainfall, geology, land use, and normalized difference vegetation index (NDVI). In the next step, flood susceptibility maps were prepared by these four methods in ArcGIS. As the last step, receiver operating characteristic (ROC) curve was drawn and the area under the curve (AUC) was calculated for quantitative assessment of each model. The results showed that the best model to estimate the susceptibility to flooding in Haraz Watershed was SI model with the prediction and success rates of 99.71 and 98.72%, respectively, followed by Wf and SE models with the AUC values of 98.1 and 96.57% for the success rate, and 97.6 and 92.42% for the prediction rate, respectively. In the SI and Wf models, the highest and lowest important parameters were the distance from river and geology. Flood susceptibility maps are informative for managers and decision makers in Haraz Watershed in order to contemplate measures to reduce human and financial losses.

  12. Landslide susceptibility assessment in Lianhua County (China): A comparison between a random forest data mining technique and bivariate and multivariate statistical models

    Science.gov (United States)

    Hong, Haoyuan; Pourghasemi, Hamid Reza; Pourtaghi, Zohre Sadat

    2016-04-01

    Landslides are an important natural hazard that causes a great amount of damage around the world every year, especially during the rainy season. The Lianhua area is located in the middle of China's southern mountainous area, west of Jiangxi Province, and is known to be an area prone to landslides. The aim of this study was to evaluate and compare landslide susceptibility maps produced using the random forest (RF) data mining technique with those produced by bivariate (evidential belief function and frequency ratio) and multivariate (logistic regression) statistical models for Lianhua County, China. First, a landslide inventory map was prepared using aerial photograph interpretation, satellite images, and extensive field surveys. In total, 163 landslide events were recognized in the study area, with 114 landslides (70%) used for training and 49 landslides (30%) used for validation. Next, the landslide conditioning factors-including the slope angle, altitude, slope aspect, topographic wetness index (TWI), slope-length (LS), plan curvature, profile curvature, distance to rivers, distance to faults, distance to roads, annual precipitation, land use, normalized difference vegetation index (NDVI), and lithology-were derived from the spatial database. Finally, the landslide susceptibility maps of Lianhua County were generated in ArcGIS 10.1 based on the random forest (RF), evidential belief function (EBF), frequency ratio (FR), and logistic regression (LR) approaches and were validated using a receiver operating characteristic (ROC) curve. The ROC plot assessment results showed that for landslide susceptibility maps produced using the EBF, FR, LR, and RF models, the area under the curve (AUC) values were 0.8122, 0.8134, 0.7751, and 0.7172, respectively. Therefore, we can conclude that all four models have an AUC of more than 0.70 and can be used in landslide susceptibility mapping in the study area; meanwhile, the EBF and FR models had the best performance for Lianhua

  13. Isotonic and hypertonic sodium loading in supine humans

    DEFF Research Database (Denmark)

    Andersen, L J; Jensen, T U; Bestle, M H

    1999-01-01

    The hypothesis that hypertonic saline infusion induces a greater natriuresis than infusion of the same amount of sodium as isotonic saline was tested in 8 supine subjects on fixed sodium intake of 150 mmol NaCl day(-1). Sodium loads equivalent to the amount of sodium contained in 10% of measured...... extracellular volume were administered intravenously over 90 min either as isotonic saline or as hypertonic saline (850 mmol L(-1)). A third series without saline infusion served as time control. Experiments lasted 8 h. Water balance and sodium loads were maintained by replacing the excreted amounts every hour...... stimulus. Renal sodium excretion increased more than a factor of four with isotonic and hypertonic saline but also increased during time control (factor of three). Cumulated sodium excretions following isotonic (131 +/- 13 mmol) and hypertonic saline (123 +/- 10 mmol) were statistically identical exceeding...

  14. Ordinal bivariate inequality

    DEFF Research Database (Denmark)

    Sonne-Schmidt, Christoffer Scavenius; Tarp, Finn; Østerdal, Lars Peter Raahave

    This paper introduces a concept of inequality comparisons with ordinal bivariate categorical data. In our model, one population is more unequal than another when they have common arithmetic median outcomes and the first can be obtained from the second by correlationincreasing switches and/or median......-preserving spreads. For the canonical 2x2 case (with two binary indicators), we derive a simple operational procedure for checking ordinal inequality relations in practice. As an illustration, we apply the model to childhood deprivation in Mozambique....

  15. Ordinal Bivariate Inequality

    DEFF Research Database (Denmark)

    Sonne-Schmidt, Christoffer Scavenius; Tarp, Finn; Østerdal, Lars Peter Raahave

    2016-01-01

    This paper introduces a concept of inequality comparisons with ordinal bivariate categorical data. In our model, one population is more unequal than another when they have common arithmetic median outcomes and the first can be obtained from the second by correlation-increasing switches and....../or median-preserving spreads. For the canonical 2 × 2 case (with two binary indicators), we derive a simple operational procedure for checking ordinal inequality relations in practice. As an illustration, we apply the model to childhood deprivation in Mozambique....

  16. Five-Parameter Bivariate Probability Distribution

    Science.gov (United States)

    Tubbs, J.; Brewer, D.; Smith, O. W.

    1986-01-01

    NASA technical memorandum presents four papers about five-parameter bivariate gamma class of probability distributions. With some overlap of subject matter, papers address different aspects of theories of these distributions and use in forming statistical models of such phenomena as wind gusts. Provides acceptable results for defining constraints in problems designing aircraft and spacecraft to withstand large wind-gust loads.

  17. Fitting statistical models in bivariate allometry.

    Science.gov (United States)

    Packard, Gary C; Birchard, Geoffrey F; Boardman, Thomas J

    2011-08-01

    Several attempts have been made in recent years to formulate a general explanation for what appear to be recurring patterns of allometric variation in morphology, physiology, and ecology of both plants and animals (e.g. the Metabolic Theory of Ecology, the Allometric Cascade, the Metabolic-Level Boundaries hypothesis). However, published estimates for parameters in allometric equations often are inaccurate, owing to undetected bias introduced by the traditional method for fitting lines to empirical data. The traditional method entails fitting a straight line to logarithmic transformations of the original data and then back-transforming the resulting equation to the arithmetic scale. Because of fundamental changes in distributions attending transformation of predictor and response variables, the traditional practice may cause influential outliers to go undetected, and it may result in an underparameterized model being fitted to the data. Also, substantial bias may be introduced by the insidious rotational distortion that accompanies regression analyses performed on logarithms. Consequently, the aforementioned patterns of allometric variation may be illusions, and the theoretical explanations may be wide of the mark. Problems attending the traditional procedure can be largely avoided in future research simply by performing preliminary analyses on arithmetic values and by validating fitted equations in the arithmetic domain. The goal of most allometric research is to characterize relationships between biological variables and body size, and this is done most effectively with data expressed in the units of measurement. Back-transforming from a straight line fitted to logarithms is not a generally reliable way to estimate an allometric equation in the original scale. © 2010 The Authors. Biological Reviews © 2010 Cambridge Philosophical Society.

  18. Covariate analysis of bivariate survival data

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, L.E.

    1992-01-01

    The methods developed are used to analyze the effects of covariates on bivariate survival data when censoring and ties are present. The proposed method provides models for bivariate survival data that include differential covariate effects and censored observations. The proposed models are based on an extension of the univariate Buckley-James estimators which replace censored data points by their expected values, conditional on the censoring time and the covariates. For the bivariate situation, it is necessary to determine the expectation of the failure times for one component conditional on the failure or censoring time of the other component. Two different methods have been developed to estimate these expectations. In the semiparametric approach these expectations are determined from a modification of Burke's estimate of the bivariate empirical survival function. In the parametric approach censored data points are also replaced by their conditional expected values where the expected values are determined from a specified parametric distribution. The model estimation will be based on the revised data set, comprised of uncensored components and expected values for the censored components. The variance-covariance matrix for the estimated covariate parameters has also been derived for both the semiparametric and parametric methods. Data from the Demographic and Health Survey was analyzed by these methods. The two outcome variables are post-partum amenorrhea and breastfeeding; education and parity were used as the covariates. Both the covariate parameter estimates and the variance-covariance estimates for the semiparametric and parametric models will be compared. In addition, a multivariate test statistic was used in the semiparametric model to examine contrasts. The significance of the statistic was determined from a bootstrap distribution of the test statistic.

  19. Some properties of a 5-parameter bivariate probability distribution

    Science.gov (United States)

    Tubbs, J. D.; Brewer, D. W.; Smith, O. E.

    1983-01-01

    A five-parameter bivariate gamma distribution having two shape parameters, two location parameters and a correlation parameter was developed. This more general bivariate gamma distribution reduces to the known four-parameter distribution. The five-parameter distribution gives a better fit to the gust data. The statistical properties of this general bivariate gamma distribution and a hypothesis test were investigated. Although these developments have come too late in the Shuttle program to be used directly as design criteria for ascent wind gust loads, the new wind gust model has helped to explain the wind profile conditions which cause large dynamic loads. Other potential applications of the newly developed five-parameter bivariate gamma distribution are in the areas of reliability theory, signal noise, and vibration mechanics.

  20. Bivariate value-at-risk

    Directory of Open Access Journals (Sweden)

    Giuseppe Arbia

    2007-10-01

    Full Text Available In this paper we extend the concept of Value-at-risk (VaR to bivariate return distributions in order to obtain measures of the market risk of an asset taking into account additional features linked to downside risk exposure. We first present a general definition of risk as the probability of an adverse event over a random distribution and we then introduce a measure of market risk (b-VaR that admits the traditional b of an asset in portfolio management as a special case when asset returns are normally distributed. Empirical evidences are provided by using Italian stock market data.

  1. Isotonized CDF estimation from judgment poststratification data with empty strata.

    Science.gov (United States)

    Wang, Xinlei; Wang, Ke; Lim, Johan

    2012-03-01

    In applications that require cost efficiency, sample sizes are typically small so that the problem of empty strata may often occur in judgment poststratification (JPS), an important variant of balanced ranked set sampling. In this article, we consider estimation of population cumulative distribution functions (CDF) from JPS samples with empty strata. In the literature, the standard and restricted CDF estimators (Stokes and Sager, 1988, Journal of the American Statistical Association 83, 374381; Frey and Ozturk, 2011, Annals of the Institute of Statistical Mathematics, to appear) do not perform well when simply ignoring empty strata. In this article, we show that the original isotonized estimator (Ozturk, 2007, Journal of Nonparametric Statistics 19, 131-144) can handle empty strata automatically through two methods, MinMax and MaxMin. However, blindly using them can result in undesirable results in either tail of the CDF. We thoroughly examine MinMax and MaxMin and find interesting results about their behaviors and performance in the presence of empty strata. Motivated by these results, we propose modified isotonized estimators to improve estimation efficiency. Through simulation and empirical studies, we show that our estimators work well in different regions of the CDF, and also improve the overall performance of estimating the whole function. © 2011, The International Biometric Society.

  2. The efficacy of isotonic and hypotonic intravenous maintenance fluid for pediatric patients: a meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Yang, Gang; Jiang, Wenjun; Wang, Xuejun; Liu, Wenying

    2015-02-01

    This study aimed to analyze the effect of isotonic versus hypotonic solution as intravenous maintenance fluid on level of plasma sodium in hospitalized children. A fully recursive literature search in May 2013 was conducted in PubMed and EMBASE to identify potentially relevant randomized controlled trials. Jadad score and allocation concealment were adopted to evaluate the methodological quality of each trial. RevMan5.2 was used for statistical analysis. Eight randomized controlled trials with 752 patients were included. Combined analysis showed a significant lower risk of hyponatremia with isotonic solution (odds ratio, 0.36; 95% confidence interval, 0.26-0.51). The isotonic intravenous maintenance did not increase the possibility of hypernatremia (odds ratio, 0.86; 95% confidence interval, 0.36-2.06). The meta-analysis revealed that there was potential risk of hyponatremia for routine infusion of hypotonic maintenance fluid. The use of isotonic solution was warranted in hospitalized pediatric patients.

  3. Geometric visualization of parallel bivariate Pareto distribution surfaces

    Directory of Open Access Journals (Sweden)

    N.H. Abdel-All

    2016-04-01

    Full Text Available In the present paper, the differential-geometrical framework for parallel bivariate Pareto distribution surfaces (P,P¯ is given. Curvatures of a curve lying on (P,P¯, are interpreted in terms of the parameters of P. Geometrical and statistical interpretations of some results are introduced and plotted.

  4. Assessing the copula selection for bivariate frequency analysis ...

    Indian Academy of Sciences (India)

    58

    J R. Stat Soc Series B Stat Methodol, 54, 171-183. Karmakar, S. & Simonovic, S. 2009. Bivariate flood frequency analysis. Part 2: a copula‐based approach with mixed marginal distributions. J. Flood Risk Manage., 2, 32-44. Katz, R. W. 2013. Statistical methods for nonstationary extremes. Extremes in a Changing. Climate.

  5. Testing bivariate independence and normality

    NARCIS (Netherlands)

    Kallenberg, W.C.M.; Ledwina, Teresa; Rafajlowicz, Ewaryst

    1997-01-01

    In many statistical studies the relationship between two random variables X and Y is investigated and in particular the question whether X and Y are independent and normally distributed is of interest. Smooth tests may be used for testing this. They consist of several components, the first measuring

  6. Isotonic vs Hypotonic Intravenous Fluids for Hospitalized Children.

    Science.gov (United States)

    McNab, Sarah

    2015-08-18

    Is isotonic fluid associated with a lower incidence of hyponatremia when compared with hypotonic fluid for maintenance intravenous fluid therapy in children? Compared with hypotonic fluid, isotonic fluid is associated with a lower incidence of hyponatremia, without evidence of an increase in adverse outcomes.

  7. Singular Isotonic Oscillator, Supersymmetry and Superintegrability

    Directory of Open Access Journals (Sweden)

    Ian Marquette

    2012-09-01

    Full Text Available In the case of a one-dimensional nonsingular Hamiltonian H and a singular supersymmetric partner H_a, the Darboux and factorization relations of supersymmetric quantum mechanics can be only formal relations. It was shown how we can construct an adequate partner by using infinite barriers placed where are located the singularities on the real axis and recover isospectrality. This method was applied to superpartners of the harmonic oscillator with one singularity. In this paper, we apply this method to the singular isotonic oscillator with two singularities on the real axis. We also applied these results to four 2D superintegrable systems with second and third-order integrals of motion obtained by Gravel for which polynomial algebras approach does not allow to obtain the energy spectrum of square integrable wavefunctions. We obtain solutions involving parabolic cylinder functions.

  8. Incomplete Bivariate Fibonacci and Lucas -Polynomials

    Directory of Open Access Journals (Sweden)

    Dursun Tasci

    2012-01-01

    Full Text Available We define the incomplete bivariate Fibonacci and Lucas -polynomials. In the case =1, =1, we obtain the incomplete Fibonacci and Lucas -numbers. If =2, =1, we have the incomplete Pell and Pell-Lucas -numbers. On choosing =1, =2, we get the incomplete generalized Jacobsthal number and besides for =1 the incomplete generalized Jacobsthal-Lucas numbers. In the case =1, =1, =1, we have the incomplete Fibonacci and Lucas numbers. If =1, =1, =1, =⌊(−1/(+1⌋, we obtain the Fibonacci and Lucas numbers. Also generating function and properties of the incomplete bivariate Fibonacci and Lucas -polynomials are given.

  9. Exact Asymptotics of Bivariate Scale Mixture Distributions

    OpenAIRE

    Hashorva, Enkelejd

    2009-01-01

    Let (RU_1, R U_2) be a given bivariate scale mixture random vector, with R>0 being independent of the bivariate random vector (U_1,U_2). In this paper we derive exact asymptotic expansions of the tail probability P{RU_1> x, RU_2> ax}, a \\in (0,1] as x tends infintiy assuming that R has distribution function in the Gumbel max-domain of attraction and (U_1,U_2) has a specific tail behaviour around some absorbing point. As a special case of our results we retrieve the exact asymptotic behaviour ...

  10. Mixed effects models with bivariate and univariate association parameters for longitudinal bivariate binary response data.

    Science.gov (United States)

    Ten Have, T R; Morabia, A

    1999-03-01

    When two binary responses are measured for each study subject across time, it may be of interest to model how the bivariate associations and marginal univariate risks involving the two responses change across time. To achieve such a goal, marginal models with bivariate log odds ratio and univariate logit components are extended to include random effects for all components. Specifically, separate normal random effects are specified on the log odds ratio scale for bivariate responses and on the logit scale for univariate responses. Assuming conditional independence given the random effects facilitates the modeling of bivariate associations across time with missing at random incomplete data. We fit the model to a dataset for which such structures are feasible: a longitudinal randomized trial of a cardiovascular educational program where the responses of interest are change in hypertension and hypercholestemia status. The proposed model is compared to a naive bivariate model that assumes independence between time points and univariate mixed effects logit models.

  11. GIS-Based bivariate statistical techniques for groundwater potential ...

    Indian Academy of Sciences (India)

    24

    these models are known as computational intelligence and machine learning techniques to use for replacing .... (NCC) using topography survey base points displaying showing the elevation altitude values which were ... lithology of an given area and affect the drainage density and can be of great big value for to evaluate ...

  12. GIS-based bivariate statistical techniques for groundwater potential ...

    Indian Academy of Sciences (India)

    % and 23.74% of the study area is covered by poor zone of groundwater potential, and 43.93% and 36.3% of Broujerd region is covered by good and very good potential zones, respectively. The validation of outcomes displayed that area ...

  13. Isotonic versus Hypotonic Parenteral Maintenance Fluids in Very Severe Pneumonia.

    Science.gov (United States)

    Ramanathan, Subramaniam; Kumar, Praveen; Mishra, Kirtisudha; Dutta, Ashok Kumar

    2016-01-01

    To compare the risk of hyponatremia between hypotonic and isotonic parenteral maintenance solutions (PMS) administered to children with very severe pneumonia, admitted in the general pediatric ward. A randomized controlled open label trial was conducted in the pediatrics department of a tertiary care medical college hospital including euvolemic children 2 mo to 5 y of age, fulfilling the WHO clinical definition of very severe pneumonia and requiring PMS. They were randomized to receive either isotonic PMS (0.9% saline in 5% dextrose and potassium chloride 20 meq/L) or hypotonic PMS (0.18% saline in 5% dextrose and potassium chloride 20 meq/L) at standard rates for next 24 h. A total of 119 children were randomized (59: Isotonic; 60: Hypototonic PMS). Nine (15%) children in the isotonic PMS group and 29 (48%) in the hypotonic PMS group developed hyponatremia during the study period, (p hypotonic group compared to the isotonic group (p < 0.001 each at 6, 12 and 24 h). The difference in mean change in serum sodium from baseline was also significant at 12 and 24 h (5.4 and 5.8 meq/L respectively; p < 0.001 each). This study demonstrates the rationality of the use of isotonic PMS in children with respiratory infections, a condition regularly encountered by most pediatricians.

  14. [Use of ultrasound for gastric volume evaluation after ingestion of different volumes of isotonic solution].

    Science.gov (United States)

    Bisinotto, Flora Margarida Barra; Naves, Aline de Araújo; Lima, Hellen Moreira de; Peixoto, Ana Cristina Abdu; Maia, Gisele Caetano; Resende Junior, Paulo Pacheco; Martins, Laura Bisinotto; Silveira, Luciano A Matias da

    The current preoperative fasting guidelines allow fluid intake up to 2hours before surgery. The aim of this study was to evaluate the gastric volume of volunteers after an overnight fast and compare it with the gastric volume 2hours after ingestion of 200 and 500mL of isotonic solution, by means of ultrasound assessment. Eighty volunteers underwent gastric ultrasound at three times: after 8hours of fasting; 2hours after ingestion of 200mL isotonic saline, followed by the first scan; and on another day, 2hours after ingestion of 500mL of the same solution after an overnight fast. The evaluation was quantitative (antrum area and gastric volume, and the ratio of participants' gastric volume/weight) and qualitative (absence or presence of gastric contents on right lateral decubitus and supine positions. A p-value0.05). Five volunteers (6.25%) had a volume/weight over 1.5mL.kg -1 at fasting and 2hours after ingestion of 200mL and 6 (7.5%) after 500mL. Qualitatively, the presence of gastric fluid occurred in more volunteers after fluid ingestion, especially 500mL (18.7%), although not statistically significant. Ultrasound assessment of gastric volume showed no significant difference, both qualitative and quantitative, 2h after ingestion of 200mL or 500mL of isotonic solution compared to fasting, although gastric fluid content has been identified in more volunteers, especially after ingestion of 500mL isotonic solution. Copyright © 2016 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  15. Use of ultrasound for gastric volume evaluation after ingestion of different volumes of isotonic solution

    Directory of Open Access Journals (Sweden)

    Flora Margarida Barra Bisinotto

    Full Text Available Abstract Background and objectives: The current preoperative fasting guidelines allow fluid intake up to 2 h before surgery. The aim of this study was to evaluate the gastric volume of volunteers after an overnight fast and compare it with the gastric volume 2 h after ingestion of 200 and 500 mL of isotonic solution, by means of ultrasound assessment. Method: Eighty volunteers underwent gastric ultrasound at three times: after 8 h of fasting; 2 h after ingestion of 200 mL isotonic saline, followed by the first scan; and on another day, 2 h after ingestion of 500 mL of the same solution after an overnight fast. The evaluation was quantitative (antrum area and gastric volume, and the ratio of participants’ gastric volume/weight and qualitative (absence or presence of gastric contents on right lateral decubitus and supine positions. A p-value 0.05. Five volunteers (6.25% had a volume/weight over 1.5 mL kg-1 at fasting and 2 h after ingestion of 200 mL and 6 (7.5% after 500 mL. Qualitatively, the presence of gastric fluid occurred in more volunteers after fluid ingestion, especially 500 mL (18.7%, although not statistically significant. Conclusion: Ultrasound assessment of gastric volume showed no significant difference, both qualitative and quantitative, 2 h after ingestion of 200 mL or 500 mL of isotonic solution compared to fasting, although gastric fluid content has been identified in more volunteers, especially after ingestion of 500 mL isotonic solution.

  16. Reliability for some bivariate beta distributions

    Directory of Open Access Journals (Sweden)

    Nadarajah Saralees

    2005-01-01

    Full Text Available In the area of stress-strength models there has been a large amount of work as regards estimation of the reliability R=Pr( Xbivariate distribution with dependence between X and Y . In particular, we derive explicit expressions for R when the joint distribution is bivariate beta. The calculations involve the use of special functions.

  17. Reliability for some bivariate gamma distributions

    Directory of Open Access Journals (Sweden)

    Nadarajah Saralees

    2005-01-01

    Full Text Available In the area of stress-strength models, there has been a large amount of work as regards estimation of the reliability R=Pr( Xbivariate distribution with dependence between X and Y . In particular, we derive explicit expressions for R when the joint distribution is bivariate gamma. The calculations involve the use of special functions.

  18. The Effects of Selection Strategies for Bivariate Loglinear Smoothing Models on NEAT Equating Functions

    Science.gov (United States)

    Moses, Tim; Holland, Paul W.

    2010-01-01

    In this study, eight statistical strategies were evaluated for selecting the parameterizations of loglinear models for smoothing the bivariate test score distributions used in nonequivalent groups with anchor test (NEAT) equating. Four of the strategies were based on significance tests of chi-square statistics (Likelihood Ratio, Pearson,…

  19. A dynamic bivariate Poisson model for analysing and forecasting match results in the English Premier League

    NARCIS (Netherlands)

    Koopman, S.J.; Lit, R.

    2015-01-01

    Summary: We develop a statistical model for the analysis and forecasting of football match results which assumes a bivariate Poisson distribution with intensity coefficients that change stochastically over time. The dynamic model is a novelty in the statistical time series analysis of match results

  20. An evaluation of isotonic "sport drinks" during labor.

    Science.gov (United States)

    Kubli, Mark; Scrutton, Mark J; Seed, Paul T; O'Sullivan, Geraldine

    2002-02-01

    We compared the metabolic effects of allowing women isotonic "sport drinks" rather than water to drink during labor. The effect of these drinks on gastric residual volume was also evaluated. Sixty women in early labor (cervical dilation isotonic sport drinks or water only. Plasma beta-hydroxybutyrate, nonesterified fatty acids, and glucose were measured in early labor and at the end of the first stage of labor. Residual gastric volume was assessed within 45 min of delivery by use of an ultrasound scanner. The incidence and volume of vomiting was recorded. At the end of the first stage of labor, plasma beta-hydroxybutyrate (P = 0.000) and nonesterified fatty acids (P = 0.000) had increased and plasma glucose (P = 0.007) had decreased significantly in the Water-Only group. Gastric antral cross-sectional area after delivery was similar in the two groups. The incidence of vomiting and the volume vomited during labor and within the hour of delivery were also similar. There was no difference between the groups in any maternal or neonatal outcome of labor. In conclusion, isotonic drinks reduce maternal ketosis in labor without increasing gastric volume. Solid foods may endanger a woman's life if consumed during labor. Isotonic sport fluids were evaluated as a nutritional alternative. Results demonstrate that mothers who have not received parenteral opioids can safely drink isotonic drinks in active labor.

  1. Almost opposite regression dependence in bivariate distributions

    OpenAIRE

    Siburg, Karl Friedrich; Stoimenov, Pavel A.

    2014-01-01

    Let X,Y be two continuous random variables. Investigating the regression dependence of Y on X, respectively, of X on Y, we show that the two of them can have almost opposite behavior. Indeed, given any e > 0, we construct a bivariate random vector (X,Y) such that the respective regression dependence measures r2|1(X,Y), r1|2(X,Y) ∈ [0,1] introduced in Dette et al. (2013) satisfy r2|1(X,Y) = 1 as well as r1|2(X,Y)

  2. Spectral density regression for bivariate extremes

    KAUST Repository

    Castro Camilo, Daniela

    2016-05-11

    We introduce a density regression model for the spectral density of a bivariate extreme value distribution, that allows us to assess how extremal dependence can change over a covariate. Inference is performed through a double kernel estimator, which can be seen as an extension of the Nadaraya–Watson estimator where the usual scalar responses are replaced by mean constrained densities on the unit interval. Numerical experiments with the methods illustrate their resilience in a variety of contexts of practical interest. An extreme temperature dataset is used to illustrate our methods. © 2016 Springer-Verlag Berlin Heidelberg

  3. Mineral Composition and Nutritive Value of Isotonic and Energy Drinks.

    Science.gov (United States)

    Leśniewicz, Anna; Grzesiak, Magdalena; Żyrnicki, Wiesław; Borkowska-Burnecka, Jolanta

    2016-04-01

    Several very popular brands of isotonic and energy drinks consumed for fluid and electrolyte supplementation and stimulation of mental or physical alertness were chosen for investigation. Liquid beverages available in polyethylene bottles and aluminum cans as well as products in the form of tablets and powder in sachets were studied. The total concentrations of 21 elements (Ag, Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Na, Ni, P, Pb, Sr, Ti, V, and Zn), both essential and toxic, were simultaneously determined in preconcentrated drink samples by inductively coupled plasma-optical emission spectrometry (ICP-OES) equipped with pneumatic and ultrasonic nebulizers. Differences between the mineral compositions of isotonic and energy drinks were evaluated and discussed. The highest content of Na was found in both isotonic and energy drinks, whereas quite high concentrations of Mg were found in isotonic drinks, and the highest amount of calcium was quantified in energy drinks. The concentrations of B, Co, Cu, Ni, and P were higher in isotonic drinks, but energy drinks contained greater quantities of Ag, Cr, Zn, Mn, and Mo and toxic elements, as Cd and Pb. A comparison of element contents with micronutrient intake and tolerable levels was performed to evaluate contribution of the investigated beverages to the daily diet. The consumption of 250 cm(3) of an isotonic drink provides from 0.32% (for Mn) up to 14.8% (for Na) of the recommended daily intake. For the energy drinks, the maximum recommended daily intake fulfillment ranged from 0.02% (for V) to 19.4 or 19.8% (for Mg and Na).

  4. Statistics

    CERN Document Server

    Hayslett, H T

    1991-01-01

    Statistics covers the basic principles of Statistics. The book starts by tackling the importance and the two kinds of statistics; the presentation of sample data; the definition, illustration and explanation of several measures of location; and the measures of variation. The text then discusses elementary probability, the normal distribution and the normal approximation to the binomial. Testing of statistical hypotheses and tests of hypotheses about the theoretical proportion of successes in a binomial population and about the theoretical mean of a normal population are explained. The text the

  5. On the Bivariate Kummer-Beta Type IV Distribution

    NARCIS (Netherlands)

    Jacobs, R.; Bekker, A.; Human, S.W.

    2012-01-01

    In this article, the non central bivariate Kummer-beta Type IV distribution is introduced and derived via the Laplace transform of the non central bivariate beta distribution by Gupta et al. (2011 ). We focus on and discuss the central bivariate Kummer-beta Type IV distribution; this distribution is

  6. Application of electronic tongue in isotonic sports drinks characterization and differentiation during storage

    OpenAIRE

    Nada Vahčić; Mirjana Hruškar; Ines Panjkota Krbavčić; Branka Levaj; I. Smola; Ksenija Marković; Major, N.

    2011-01-01

    The electronic tongue or taste sensor system, comprised of seven potentiometric sensors, was applied as a tool in isotonic sports drinks analyses and characterization. Recently, electronic tongue systems showed large potential in food quality control, and for the first time it was used in isotonic sports drinks differentiation. The ability of the electronic tongue to differentiate between isotonic sports drinks samples and to monitor isotonic sports drinks during shelf life was evaluated by P...

  7. Statistics

    Science.gov (United States)

    Links to sources of cancer-related statistics, including the Surveillance, Epidemiology and End Results (SEER) Program, SEER-Medicare datasets, cancer survivor prevalence data, and the Cancer Trends Progress Report.

  8. Two new bivariate zero-inflated generalized Poisson distributions with a flexible correlation structure

    Directory of Open Access Journals (Sweden)

    Chi Zhang

    2015-05-01

    Full Text Available To model correlated bivariate count data with extra zero observations, this paper proposes two new bivariate zero-inflated generalized Poisson (ZIGP distributions by incorporating a multiplicative factor (or dependency parameter λ, named as Type I and Type II bivariate ZIGP distributions, respectively. The proposed distributions possess a flexible correlation structure and can be used to fit either positively or negatively correlated and either over- or under-dispersed count data, comparing to the existing models that can only fit positively correlated count data with over-dispersion. The two marginal distributions of Type I bivariate ZIGP share a common parameter of zero inflation while the two marginal distributions of Type II bivariate ZIGP have their own parameters of zero inflation, resulting in a much wider range of applications. The important distributional properties are explored and some useful statistical inference methods including maximum likelihood estimations of parameters, standard errors estimation, bootstrap confidence intervals and related testing hypotheses are developed for the two distributions. A real data are thoroughly analyzed by using the proposed distributions and statistical methods. Several simulation studies are conducted to evaluate the performance of the proposed methods.

  9. Bivariate Rayleigh Distribution and its Properties

    Directory of Open Access Journals (Sweden)

    Ahmad Saeed Akhter

    2007-01-01

    Full Text Available Rayleigh (1880 observed that the sea waves follow no law because of the complexities of the sea, but it has been seen that the probability distributions of wave heights, wave length, wave induce pitch, wave and heave motions of the ships follow the Rayleigh distribution. At present, several different quantities are in use for describing the state of the sea; for example, the mean height of the waves, the root mean square height, the height of the “significant waves” (the mean height of the highest one-third of all the waves the maximum height over a given interval of the time, and so on. At present, the ship building industry knows less than any other construction industry about the service conditions under which it must operate. Only small efforts have been made to establish the stresses and motions and to incorporate the result of such studies in to design. This is due to the complexity of the problem caused by the extensive variability of the sea and the corresponding response of the ships. Although the problem appears feasible, yet it is possible to predict service conditions for ships in an orderly and relatively simple manner Rayleigh (1980 derived it from the amplitude of sound resulting from many independent sources. This distribution is also connected with one or two dimensions and is sometimes referred to as “random walk” frequency distribution. The Rayleigh distribution can be derived from the bivariate normal distribution when the variate are independent and random with equal variances. We try to construct bivariate Rayleigh distribution with marginal Rayleigh distribution function and discuss its fundamental properties.

  10. Isotonic sports drink promotes rehydration and decreases proteinuria following karate training

    Directory of Open Access Journals (Sweden)

    Simone Geraldini

    Full Text Available Abstract Introduction: Adequate hydration status in the sport is essential for good health, yet the relationship between hydration, proteinuria and sports is little studied. Objective: To analyze the influence of an isotonic sports drink as rehydration strategy on the hydration status and proteinuria after karate training. Methods: Ten athletes participated in this study. In the first session of standard training, called observation training session (STO, the athletes hydrated themselves according to their habits, and in the second session of standard training, called nutritional intervention training session (STIN, an ideal practice of hydration protocol was followed, using an isotonic sports drink as a rehydration liquid during the training. The hydration status was verified by monitoring the body weight before and after training, the urine specific gravity pre-and post-training and the urine volume post-training. To observe the influence of practice of hydration on the renal function post exercise proteinuria was measured. Results: We observed a statistically significant difference in urine density between the samples pre- and post-exercise only on STIN (p = 0.047. When we compare the sessions, there was a lower variation in body weight (p = 0.011 and higher urinary volume (p < 0.001, on nutritional intervention training. In STO, there was a higher percentage of athletes who showed proteinuria (70% compared to the STIN (50% in the urine sample after training. Conclusion: The use of isotonic sports drink as practice of hydration by karate athletes promoted rehydration during one session of training and reduce post-training proteinuria.

  11. Latent class bivariate model for the meta-analysis of diagnostic test accuracy studies

    NARCIS (Netherlands)

    Eusebi, P.; Reitsma, J.B.; Vermunt, J.K.

    2014-01-01

    Background Several types of statistical methods are currently available for the meta-analysis of studies on diagnostic test accuracy. One of these methods is the Bivariate Model which involves a simultaneous analysis of the sensitivity and specificity from a set of studies. In this paper, we review

  12. Current misuses of multiple regression for investigating bivariate hypotheses: an example from the organizational domain.

    Science.gov (United States)

    O'Neill, Thomas A; McLarnon, Matthew J W; Schneider, Travis J; Gardner, Robert C

    2014-09-01

    By definition, multiple regression (MR) considers more than one predictor variable, and each variable's beta will depend on both its correlation with the criterion and its correlation with the other predictor(s). Despite ad nauseam coverage of this characteristic in organizational psychology and statistical texts, researchers' applications of MR in bivariate hypothesis testing has been the subject of recent and renewed interest. Accordingly, we conducted a targeted survey of the literature by coding articles, covering a five-year span from two top-tier organizational journals, that employed MR for testing bivariate relations. The results suggest that MR coefficients, rather than correlation coefficients, were most common for testing hypotheses of bivariate relations, yet supporting theoretical rationales were rarely offered. Regarding the potential impact on scientific advancement, in almost half of the articles reviewed (44 %), at least one conclusion of each study (i.e., that the hypothesis was or was not supported) would have been different, depending on the author's use of correlation or beta to test the bivariate hypothesis. It follows that inappropriate decisions to interpret the correlation versus the beta will affect the accumulation of consistent and replicable scientific evidence. We conclude with recommendations for improving bivariate hypothesis testing.

  13. Predicting Number of Zombies in a DDoS Attacks Using Isotonic Regression

    Science.gov (United States)

    Gupta, B. B.; Jamali, Nadeem

    Anomaly based DDoS detection systems construct profile of the traffic normally seen in the network, and identify anomalies whenever traffic deviate from normal profile beyond a threshold. This deviation in traffic beyond threshold is used in the past for DDoS detection but not for finding number of zombies. This chapter presents an approach that utilizes this deviation in traffic to predict number of zombies using isotonic regression model. A relationship is established between number of zombies and observed deviation in sample entropy. Internet type topologies used for simulation are generated using Transit-Stub model of GT-ITM topology generator. NS-2 network simulator on Linux platform is used as simulation test bed for launching DDoS attacks with varied number of zombies. Various statistical performance measures are used to measure the performance of the regression model. The simulation results are promising as we are able to predict number of zombies efficiently with very less error rate using isotonic regression model.

  14. Isotonic sports drink promotes rehydration and decreases proteinuria following karate training.

    Science.gov (United States)

    Geraldini, Simone; Cruz, Igor de Freitas; Romero, Alexandre; Fonseca, Fernando Luiz Affonso; Campos, Michelle Parreira de

    2017-01-01

    Adequate hydration status in the sport is essential for good health, yet the relationship between hydration, proteinuria and sports is little studied. To analyze the influence of an isotonic sports drink as rehydration strategy on the hydration status and proteinuria after karate training. Ten athletes participated in this study. In the first session of standard training, called observation training session (STO), the athletes hydrated themselves according to their habits, and in the second session of standard training, called nutritional intervention training session (STIN), an ideal practice of hydration protocol was followed, using an isotonic sports drink as a rehydration liquid during the training. The hydration status was verified by monitoring the body weight before and after training, the urine specific gravity pre-and post-training and the urine volume post-training. To observe the influence of practice of hydration on the renal function post exercise proteinuria was measured. We observed a statistically significant difference in urine density between the samples pre- and post-exercise only on STIN (p = 0.047). When we compare the sessions, there was a lower variation in body weight (p = 0.011) and higher urinary volume (p sports drink as practice of hydration by karate athletes promoted rehydration during one session of training and reduce post-training proteinuria.

  15. Corneal Thickness During Corneal Collagen Cross-Linking with Isotonic Riboflavin Solution without Dextran

    Directory of Open Access Journals (Sweden)

    Refik Oltulu

    2014-08-01

    Full Text Available Objectives: To monitor the corneal thickness change during the dextran-free isotonic riboflavin solution-aided corneal collagen crosslinking procedure in keratoconus patients. Materials and Methods: Corneal thickness measurements during the corneal collagen cross-linking (CXL treatment for progressive keratoconus were evaluated. The corneal thickness measurements were obtained with ultrasonic pachymetry device at five different time points: 0, 15, and 30 minutes after epithelial removal and 15 and 30 minutes after the initiation of UVA irradiation. Results: Twenty-four eyes of 24 patients with progressive keratoconus were included in the study. The thinnest pachymetric values obtained at the 0, 15, and 30 minute measurements after corneal deepithelisation were 409.38±10.43 µm (383-435 µm, 434.56±17.68 µm (400-485 µm, and 457.44±21.78 µm (428-516 µm, respectively. Pachymetric values obtained at 15 and 30 minutes after UVA application to the cornea were 471.69±23.38 µm (439-526 µm and 482.63±23.69 µm (436-524 µm, respectively. The gradual increase was found to be statistically significant when each measurement was compared with the previous values (p<0.001. Conclusion: We found that the corneal thickness was not decreased during the CXL with dextran-free isotonic riboflavin solution; on the contrary, corneal thickness was increased regularly during the procedure. (Turk J Ophthalmol 2014; 44: 272-4

  16. ROLE OF ISOTONIC SALINE NASAL IRRIGATION IN SEASONAL ALLERGIC RHINITIS

    Directory of Open Access Journals (Sweden)

    Lingaiah Jadi

    2017-06-01

    Full Text Available BACKGROUND Allergic rhinitis is IgE-mediated nasal mucosal hypersensitivity reaction after exposure to the offending allergen. Treatment options for allergic rhinitis includes allergen avoidance, immunotherapy, local/systemic antihistamines and steroids. Nasal saline irrigation is a possible potential treatment or adjunct to pharmacological treatment. It produces improvement in nasal symptoms, reduction in medicine consumption, by acceleration of mucociliary clearance time and thus improvement in quality of life. MATERIALS AND METHODS Our prospective study was performed with 52 patients in between the ages of 20-60 years who presented with recurrent (more than 1 year symptoms of seasonal allergic rhinitis. Isotonic saline nasal irrigation was added for a period of 8 weeks along with other measures of allergic rhinitis treatment such as allergen avoidance and pharmacotherapy and quality of life was assessed by the severity of symptoms. RESULTS This study was designed to evaluate the reduction in symptom score with the use of isotonic saline nasal irrigation given twice daily for 8 weeks in seasonal allergic rhinitis along with the standard treatment i.e. antihistamines and intranasal corticosteroid spray. Total of 52 patients were studied. The usage of isotonic saline nasal irrigation improved the quality of life in terms of reduction in the severity, frequency and duration of symptoms compared to the relief he had in the previous years when he used only intranasal steroids. CONCLUSION Nasal irrigation with isotonic saline is a safe, inexpensive, easy to use and effective adjunctive therapy in patients with seasonal allergic rhinitis to alleviate the symptoms of allergic rhinitis. It resulted in significant improvement in the quality of life.

  17. Invariance principles for linear processes with application to isotonic regression

    OpenAIRE

    Dedecker, Jérôme; Merlevède, Florence; Peligrad, Magda

    2009-01-01

    In this paper, we prove maximal inequalities and study the functional central limit theorem for the partial sums of linear processes generated by dependent innovations. Due to the general weights, these processes can exhibit long-range dependence and the limiting distribution is a fractional Brownian motion. The proofs are based on new approximations by a linear process with martingale difference innovations. The results are then applied to study an estimator of the isotonic regression when t...

  18. An assessment on the use of bivariate, multivariate and soft ...

    Indian Academy of Sciences (India)

    The paper presented herein compares and discusses the use of bivariate, multivariate and soft computing techniques for collapse susceptibility modelling. Conditional probability (CP), logistic regression (LR) and artificial neural networks (ANN) models representing the bivariate, multivariate and soft computing techniques ...

  19. Some bivariate distributions for modeling the strength properties of lumber

    Science.gov (United States)

    Richard A. Johnson; James W. Evans; David W. Green

    Accurate modeling of the joint stochastic nature of the strength properties of dimension lumber is essential to the determination of reliability-based design safety factors. This report reviews the major techniques for obtaining bivariate distributions and then discusses bivariate distributions whose marginal distributions suggest they might be useful for modeling the...

  20. A comparison of bivariate and univariate QTL mapping in livestock populations

    Directory of Open Access Journals (Sweden)

    Sorensen Daniel

    2003-11-01

    Full Text Available Abstract This study presents a multivariate, variance component-based QTL mapping model implemented via restricted maximum likelihood (REML. The method was applied to investigate bivariate and univariate QTL mapping analyses, using simulated data. Specifically, we report results on the statistical power to detect a QTL and on the precision of parameter estimates using univariate and bivariate approaches. The model and methodology were also applied to study the effectiveness of partitioning the overall genetic correlation between two traits into a component due to many genes of small effect, and one due to the QTL. It is shown that when the QTL has a pleiotropic effect on two traits, a bivariate analysis leads to a higher statistical power of detecting the QTL and to a more precise estimate of the QTL's map position, in particular in the case when the QTL has a small effect on the trait. The increase in power is most marked in cases where the contributions of the QTL and of the polygenic components to the genetic correlation have opposite signs. The bivariate REML analysis can successfully partition the two components contributing to the genetic correlation between traits.

  1. Stress-strength reliability for general bivariate distributions

    Directory of Open Access Journals (Sweden)

    Alaa H. Abdel-Hamid

    2016-10-01

    Full Text Available An expression for the stress-strength reliability R=P(X1bivariate distribution. Such distribution includes bivariate compound Weibull, bivariate compound Gompertz, bivariate compound Pareto, among others. In the parametric case, the maximum likelihood estimates of the parameters and reliability function R are obtained. In the non-parametric case, point and interval estimates of R are developed using Govindarajulu's asymptotic distribution-free method when X1 and X2 are dependent. An example is given when the population distribution is bivariate compound Weibull. Simulation is performed, based on different sample sizes to study the performance of estimates.

  2. STUDI PERBANDINGAN ANTARA ALGORITMA BIVARIATE MARGINAL DISTRIBUTION DENGAN ALGORITMA GENETIKA

    Directory of Open Access Journals (Sweden)

    Chastine Fatichah

    2006-01-01

    Full Text Available Bivariate Marginal Distribution Algorithm is extended from Estimation of Distribution Algorithm. This heuristic algorithm proposes the new approach for recombination of generate new individual that without crossover and mutation process such as genetic algorithm. Bivariate Marginal Distribution Algorithm uses connectivity variable the pair gene for recombination of generate new individual. Connectivity between variable is doing along optimization process. In this research, genetic algorithm performance with one point crossover is compared with Bivariate Marginal Distribution Algorithm performance in case Onemax, De Jong F2 function, and Traveling Salesman Problem. In this research, experimental results have shown performance the both algorithm is dependence of parameter respectively and also population size that used. For Onemax case with size small problem, Genetic Algorithm perform better with small number of iteration and more fast for get optimum result. However, Bivariate Marginal Distribution Algorithm perform better of result optimization for case Onemax with huge size problem. For De Jong F2 function, Genetic Algorithm perform better from Bivariate Marginal Distribution Algorithm of a number of iteration and time. For case Traveling Salesman Problem, Bivariate Marginal Distribution Algorithm have shown perform better from Genetic Algorithm of optimization result. Abstract in Bahasa Indonesia : Bivariate Marginal Distribution Algorithm merupakan perkembangan lebih lanjut dari Estimation of Distribution Algorithm. Algoritma heuristik ini mengenalkan pendekatan baru dalam melakukan rekombinasi untuk membentuk individu baru, yaitu tidak menggunakan proses crossover dan mutasi seperti pada Genetic Algorithm. Bivariate Marginal Distribution Algorithm menggunakan keterkaitan pasangan variabel dalam melakukan rekombinasi untuk membentuk individu baru. Keterkaitan antar variabel tersebut ditemukan selama proses optimasi berlangsung. Aplikasi yang

  3. Effect of Unilateral Isotonic Contraction on EMG Activities of the Contralateral Unexercised Limb

    OpenAIRE

    湯浅, 景元; 島野, 敬四郎; 内藤, 譲; Kagemoto, YUASA; Keishiro, SHIMANO; Yuzuru, NAITO; 中京大学; 中京大学大学院; 中京大学大学院

    1995-01-01

    Five college male volunteers performed unilateral isotonic contractions at intensities of 20, 40, 60, 80, and 100% of 1RM. The integrated EMGs from the biceps of the unexercised limb were recorded during unilateral isotonic contractions at each intensity. The integrated EMGs of the unexercised limb increased with the increment of intensity applied to the exercised limb. These results indicated that unilateral isotonic contractions might have an effect on muscular activity of the unexercised c...

  4. Local reactions after i.v. injections of diazepam, flunitrazepam and isotonic saline.

    Science.gov (United States)

    Mikkelsen, H; Hoel, T M; Bryne, H; Krohn, C D

    1980-08-01

    Local reactions after i.v. injection of diazepam, flunitrazepam and isotonic saline were studied in patients who received extradural analgesia or general anaesthesia. The frequency of thrombophlebitis on the 1st, 3rd and 5th days after the injection of diazepam was 2.1%, 17.0% and 14.9% respectively, after flunitrazepam 10.0%. 10.0% and 14.0%, and after saline 0%, 6.7% and 4.4%. The differences between the groups were not statistically significant (P > 0.05). One month after the injection 15.6% in the diazepam group, 8.5% in the flunitrazepam group and 9.3% in the saline group had pain or tenderness in the arm used for the injection.

  5. Copula bivariate probit models: with an application to medical expenditures.

    Science.gov (United States)

    Winkelmann, Rainer

    2012-12-01

    The bivariate probit model is frequently used for estimating the effect of an endogenous binary regressor (the 'treatment') on a binary health outcome variable. This paper discusses simple modifications that maintain the probit assumption for the marginal distributions while introducing non-normal dependence using copulas. In an application of the copula bivariate probit model to the effect of insurance status on the absence of ambulatory health care expenditure, a model based on the Frank copula outperforms the standard bivariate probit model. Copyright © 2011 John Wiley & Sons, Ltd.

  6. Approximation of bivariate copulas by patched bivariate Fréchet copulas

    KAUST Repository

    Zheng, Yanting

    2011-03-01

    Bivariate Fréchet (BF) copulas characterize dependence as a mixture of three simple structures: comonotonicity, independence and countermonotonicity. They are easily interpretable but have limitations when used as approximations to general dependence structures. To improve the approximation property of the BF copulas and keep the advantage of easy interpretation, we develop a new copula approximation scheme by using BF copulas locally and patching the local pieces together. Error bounds and a probabilistic interpretation of this approximation scheme are developed. The new approximation scheme is compared with several existing copula approximations, including shuffle of min, checkmin, checkerboard and Bernstein approximations and exhibits better performance, especially in characterizing the local dependence. The utility of the new approximation scheme in insurance and finance is illustrated in the computation of the rainbow option prices and stop-loss premiums. © 2010 Elsevier B.V.

  7. Evaluation dam overtopping risk based on univariate and bivariate flood frequency analysis

    Science.gov (United States)

    Goodarzi, E.; Mirzaei, M.; Shui, L. T.; Ziaei, M.

    2011-11-01

    There is a growing tendency to assess the safety levels of existing dams based on risk and uncertainty analysis using mathematical and statistical methods. This research presents the application of risk and uncertainty analysis to dam overtopping based on univariate and bivariate flood frequency analyses by applying Gumbel logistic distribution for the Doroudzan earth-fill dam in south of Iran. The bivariate frequency analysis resulted in six inflow hydrographs with a joint return period of 100-yr. The overtopping risks were computed for all of those hydrographs considering quantile of flood peak discharge (in particular 100-yr), initial depth of water in the reservoir, and discharge coefficient of spillway as uncertain variables. The maximum height of the water, as most important factor in the overtopping analysis, was evaluated using reservoir routing and the Monte Carlo and Latin hypercube techniques were applied for uncertainty analysis. Finally, the achieved results using both univariate and bivariate frequency analysis have been compared to show the significance of bivariate analyses on dam overtopping.

  8. Bivariate functional principal components analysis: considerations for use with multivariate movement signatures in sports biomechanics.

    Science.gov (United States)

    Warmenhoven, John; Cobley, Stephen; Draper, Conny; Harrison, Andrew; Bargary, Norma; Smith, Richard

    2017-11-10

    Sporting performance is often investigated through graphical observation of key technical variables that are representative of whole movements. The presence of differences between athletes in such variables has led to terms such as movement signatures being used. These signatures can be multivariate (multiple time-series observed concurrently), and also be composed of variables measured relative to different scales. Analytical techniques from areas of statistics such as Functional Data Analysis (FDA) present a practical alternative for analysing multivariate signatures. When applied to concurrent bivariate time-series multivariate functional principal components analysis (referred to as bivariate fPCA or bfPCA in this paper) has demonstrated preliminary application in biomechanical contexts. Despite this, given the infancy of bfPCA in sports biomechanics there are still necessary considerations for its use with non-conventional or complex bivariate structures. This paper focuses on the application of bfPCA to the force-angle graph in on-water rowing, which is a bivariate structure composed of variables with different units. A normalisation approach is proposed to investigate and standardise differences in variability between the two variables. The results of bfPCA applied to the non-normalised data and normalised data are then compared. Considerations and recommendations for the application of bfPCA in this context are also provided.

  9. Generalized quantum isotonic nonlinear oscillator in d dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Richard L [Department of Mathematics and Statistics, Concordia University, 1455 de Maisonneuve Boulevard West, Montreal, Quebec H3G 1M8 (Canada); Saad, Nasser [Department of Mathematics and Statistics, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI C1A 4P3 (Canada); Yesiltas, Oezlem, E-mail: rhall@mathstat.concordia.c, E-mail: nsaad@upei.c, E-mail: yesiltas@gazi.edu.t [Department of Physics, Faculty of Arts and Sciences, Gazi University, 06500 Ankara (Turkey)

    2010-11-19

    We present a supersymmetric analysis for the d-dimensional Schroedinger equation with the generalized isotonic nonlinear-oscillator potential V(r) = B{sup 2}/r{sup 2} + {omega}{sup 2}r{sup 2} + 2g(r{sup 2} - a{sup 2})/(r{sup 2} + a{sup 2}){sup 2}, B {>=} 0. We show that the eigenequation for this potential is exactly solvable provided g = 2 and ({omega}a{sup 2}){sup 2} = B{sup 2} + (l + (d - 2)/2){sup 2}. Under these conditions, we obtain explicit formulae for all the energies and normalized bound-state wavefunctions.

  10. Copula bivariate probit models: with an application to medical expenditures

    OpenAIRE

    Winkelmann, Rainer

    2011-01-01

    The bivariate probit model is frequently used for estimating the effect of an endogenous binary regressor (the "treatment") on a binary health outcome variable. This paper discusses simple modifications that maintain the probit assumption for the marginal distributions while introducing non-normal dependence using copulas. In an application of the copula bivariate probit model to the effect of insurance status on the absence of ambulatory health care expen- diture, a model based on the Frank ...

  11. Latent class bivariate model for the meta-analysis of diagnostic test accuracy studies.

    Science.gov (United States)

    Eusebi, Paolo; Reitsma, Johannes B; Vermunt, Jeroen K

    2014-07-11

    Several types of statistical methods are currently available for the meta-analysis of studies on diagnostic test accuracy. One of these methods is the Bivariate Model which involves a simultaneous analysis of the sensitivity and specificity from a set of studies. In this paper, we review the characteristics of the Bivariate Model and demonstrate how it can be extended with a discrete latent variable. The resulting clustering of studies yields additional insight into the accuracy of the test of interest. A Latent Class Bivariate Model is proposed. This model captures the between-study variability in sensitivity and specificity by assuming that studies belong to one of a small number of latent classes. This yields both an easier to interpret and a more precise description of the heterogeneity between studies. Latent classes may not only differ with respect to the average sensitivity and specificity, but also with respect to the correlation between sensitivity and specificity. The Latent Class Bivariate Model identifies clusters of studies with their own estimates of sensitivity and specificity. Our simulation study demonstrated excellent parameter recovery and good performance of the model selection statistics typically used in latent class analysis. Application in a real data example on coronary artery disease showed that the inclusion of latent classes yields interesting additional information. Our proposed new meta-analysis method can lead to a better fit of the data set of interest, less biased estimates and more reliable confidence intervals for sensitivities and specificities. But even more important, it may serve as an exploratory tool for subsequent sub-group meta-analyses.

  12. RMF+BCS Description of Some Traditional Neutron Magic Isotones

    Directory of Open Access Journals (Sweden)

    Saxena G.

    2014-03-01

    Full Text Available The traditional neutron magic nuclei with N = 8, 20, 28, 50, 82 and 126, and those with neutron sub-magic number N = 40 are investigated within the relativistic mean-field plus BCS (RMF+BCS approach. The results indicate appearance of new proton magic numbers as well as the disappearance of conventional magic numbers for nuclei with extreme isospin values. The calculated energies and densities do not indicate any tendency for the proton halo formations in any of the proton rich isotones due to Coulomb interaction and different single particle spectra. However, the potential barrier provided by the Coulomb interaction and that due to the centrifugal force may cause along delay in the actual decay of proton rich nucleus resulting the extended drip line.

  13. Semiparametric analysis of two-level bivariate binary data.

    Science.gov (United States)

    Naskar, Malay; Das, Kalyan

    2006-12-01

    In medical studies, paired binary responses are often observed for each study subject over timepoints or clusters. A primary interest is to investigate how the bivariate association and marginal univariate risks are affected by repeated measurements on each subject. To achieve this we propose a very general class of semiparametric bivariate binary models. The subject-specific effects involved in the bivariate log odds ratio and the univariate logit components are assumed to follow a nonparametric Dirichlet process (DP). We propose a hybrid method to draw model-based inferences. In the framework of the proposed hybrid method, estimation of parameters is done by implementing the Monte Carlo expectation-maximization algorithm. The proposed methodology is illustrated through a study on the effectiveness of tibolone for reducing menopausal problems experienced by Indian women. A simulation study is also conducted to evaluate the efficiency of the new methodology.

  14. A bivariate cumulative probit regression model for ordered categorical data.

    Science.gov (United States)

    Kim, K

    1995-06-30

    This paper proposes a latent variable regression model for bivariate ordered categorical data and develops the necessary numerical procedure for parameter estimation. The proposed model is an extension of the standard bivariate probit model for dichotomous data to ordered categorical data with more than two categories for each margin. In addition, the proposed model allows for different covariates for the margins, which is characteristic of data from typical ophthalmological studies. It utilizes the stochastic ordering implicit in the data and the correlation coefficient of the bivariate normal distribution in expressing intra-subject dependency. Illustration of the proposed model uses data from the Wisconsin Epidemiologic Study of Diabetic Retinopathy for identifying risk factors for diabetic retinopathy among younger-onset diabetics. The proposed regression model also applies to other clinical or epidemiological studies that involve paired organs.

  15. Jacobi Fiber Surfaces for Bivariate Reeb Space Computation.

    Science.gov (United States)

    Tierny, Julien; Carr, Hamish

    2017-01-01

    This paper presents an efficient algorithm for the computation of the Reeb space of an input bivariate piecewise linear scalar function f defined on a tetrahedral mesh. By extending and generalizing algorithmic concepts from the univariate case to the bivariate one, we report the first practical, output-sensitive algorithm for the exact computation of such a Reeb space. The algorithm starts by identifying the Jacobi set of f, the bivariate analogs of critical points in the univariate case. Next, the Reeb space is computed by segmenting the input mesh along the new notion of Jacobi Fiber Surfaces, the bivariate analog of critical contours in the univariate case. We additionally present a simplification heuristic that enables the progressive coarsening of the Reeb space. Our algorithm is simple to implement and most of its computations can be trivially parallelized. We report performance numbers demonstrating orders of magnitude speedups over previous approaches, enabling for the first time the tractable computation of bivariate Reeb spaces in practice. Moreover, unlike range-based quantization approaches (such as the Joint Contour Net), our algorithm is parameter-free. We demonstrate the utility of our approach by using the Reeb space as a semi-automatic segmentation tool for bivariate data. In particular, we introduce continuous scatterplot peeling, a technique which enables the reduction of the cluttering in the continuous scatterplot, by interactively selecting the features of the Reeb space to project. We provide a VTK-based C++ implementation of our algorithm that can be used for reproduction purposes or for the development of new Reeb space based visualization techniques.

  16. Bivariate sub-Gaussian model for stock index returns

    Science.gov (United States)

    Jabłońska-Sabuka, Matylda; Teuerle, Marek; Wyłomańska, Agnieszka

    2017-11-01

    Financial time series are commonly modeled with methods assuming data normality. However, the real distribution can be nontrivial, also not having an explicitly formulated probability density function. In this work we introduce novel parameter estimation and high-powered distribution testing methods which do not rely on closed form densities, but use the characteristic functions for comparison. The approach applied to a pair of stock index returns demonstrates that such a bivariate vector can be a sample coming from a bivariate sub-Gaussian distribution. The methods presented here can be applied to any nontrivially distributed financial data, among others.

  17. Application of electronic tongue in isotonic sports drinks characterization and differentiation during storage

    Directory of Open Access Journals (Sweden)

    Nada Vahčić

    2011-01-01

    Full Text Available The electronic tongue or taste sensor system, comprised of seven potentiometric sensors, was applied as a tool in isotonic sports drinks analyses and characterization. Recently, electronic tongue systems showed large potential in food quality control, and for the first time it was used in isotonic sports drinks differentiation. The ability of the electronic tongue to differentiate between isotonic sports drinks samples and to monitor isotonic sports drinks during shelf life was evaluated by PCA analysis. The obtained results showed that the electronic tongue system was capable of differentiating between differently flavoured isotonic sports drinks samples and was able to monitor the changes in isotonic sports drinks samples during storage. High correlations of the developed PLS models between the observed sensory taste attributes (sweet, sour, bitter taste intensity and chemical senses intensity and physicochemical parameters (electrical conductivity, refractometric value, pH value and predicted values of sensory taste attributes and physicochemical parameters evaluated by electronic tongue, confirmed the performance of the electronic tongue and also indicate that the electronic tongue system can be used for rapid evaluation of sensory taste attributes and physicochemical parameters of isotonic sports drinks.

  18. Optimizing an objective function under a bivariate probability model

    NARCIS (Netherlands)

    X. Brusset; N.M. Temme (Nico)

    2007-01-01

    htmlabstractThe motivation of this paper is to obtain an analytical closed form of a quadratic objective function arising from a stochastic decision process with bivariate exponential probability distribution functions that may be dependent. This method is applicable when results need to be

  19. About some properties of bivariate splines with shape parameters

    Science.gov (United States)

    Caliò, F.; Marchetti, E.

    2017-07-01

    The paper presents and proves geometrical properties of a particular bivariate function spline, built and algorithmically implemented in previous papers. The properties typical of this family of splines impact the field of computer graphics in particular that of the reverse engineering.

  20. The effect on serum enzymes of intramuscular injections of digoxin, bumetanide, pentazocine and isotonic sodium chloride

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Damsgaard, T

    1976-01-01

    Intramuscular injections of digoxin, bumetanide, pentazocine or isotonic sodium chloride have been given to 39 patients. We followed the serum concentrations of creatine kinase (CK), aspartate aminotransferase (ASAT), lactate dehydrogenase (LDH) and LDH isoenzymes for 4 days. Ten patients receiving...

  1. A COMPARISON OF SOME ROBUST BIVARIATE CONTROL CHARTS FOR INDIVIDUAL OBSERVATIONS

    Directory of Open Access Journals (Sweden)

    Moustafa Omar Ahmed Abu - Shawiesh

    2014-06-01

    Full Text Available This paper proposed and considered some bivariate control charts to monitor individual observations from a statistical process control. Usual control charts which use mean and variance-covariance estimators are sensitive to outliers. We consider the following robust alternatives to the classical Hoteling's T2: T2MedMAD, T2MCD, T2MVE a simulation study has been conducted to compare the performance of these control charts. Two real life data are analyzed to illustrate the application of these robust alternatives.

  2. Effect of an isotonic rehydration sports drink and exercise on urolithiasis in rats

    Directory of Open Access Journals (Sweden)

    Abreu N.P.

    2005-01-01

    Full Text Available The objective of the present study was to evaluate the role of physical exercise as well as the influence of hydration with an isotonic sports drink on renal function in male Wistar rats. Four groups were studied over a period of 42 days: 1 control (N = 9; 2 physical exercise (Exe, N = 7; 3 isotonic drink (Drink, N = 8; 4 physical exercise + isotonic drink (Exe + Drink, N = 8. Physical exercise consisted of running on a motor-driven treadmill for 1 h/day, at 20 m/min, 5 days a week. The isotonic sports drink was a commercial solution used by athletes for rehydration after physical activity, 2 ml administered by gavage twice a day. Urine cultures were performed in all animals. Twenty-four-hour urine samples were collected in metabolic cages at the beginning and at the end of the protocol period. Urinary and plasma parameters (sodium, potassium, urea, creatinine, calcium did not differ among groups. However, an amorphous material was observed in the bladders of animals in the Exe + Drink and Drink groups. Characterization of the material by Western blot revealed the presence of Tamm-Horsfall protein and angiotensin converting enzyme. Physical exercise and the isotonic drink did not change the plasma or urinary parameters measured. However, the isotonic drink induced the formation of intravesical matrix, suggesting a potential lithogenic risk.

  3. Hypotonic versus isotonic maintenance fluids in critically ill pediatric patients: a randomized controlled trial.

    Science.gov (United States)

    Jorro Barón, Facundo A; Meregalli, Claudia N; Rombolá, Valeria A; Bolasell, Cecilia; Pigliapoco, Vilma E; Bartoletti, Silvia E; Debaisi, Gustavo E

    2013-01-01

    Hypotonic fluids have been associated with the development of iatrogenic hyponatremia. To assess variations in serum sodium (sNa) following the intravenous administration of isotonic maintenance fluids (0.9% NaCl/5% dextrose) compared to hypotonic maintenance fluids (0.45% NaCl/5% dextrose). Randomized, controlled, double-blind clinical trial. Pediatric patients with an expected length of stay in the intensive care unit of more than 24 hours were enrolled, with normal serum Na, and IV fluids >80% of total maintenance fluids. Serum Na level was measured before administering maintenance fluids and when reducing the administration to hypotonic (n= 32) or isotonic (n= 31) maintenance fluids. Baseline characteristics were similar in both groups. There were no differences in terms of volume of fluid administered (hypotonic group: 865 ± 853 mL; isotonic group: 778 ± 649 mL; p= 0.654) or infusion duration (hypotonic group: 24 ± 10.8 hours; isotonic group: 27.6 ± 12.8 hours; p= 0.231). A difference was found in the serum Na following the administration of maintenance fluids (hypotonic group: 137.8 ± 4.3 mmol/L; isotonic group: 140.0 ± 4.1 mmol/L, p= 0.04). None of these two maintenance fluids increased the risk of hyponatremia (Na 145 mmol/L). Neither hypotonic nor isotonic maintenance fluids increased the risk of developing iatrogenic hyponatremia with the 24 hour infusion.

  4. Bivariate modelling of clustered continuous and ordered categorical outcomes.

    Science.gov (United States)

    Catalano, P J

    1997-04-30

    Simultaneous observation of continuous and ordered categorical outcomes for each subject is common in biomedical research but multivariate analysis of the data is complicated by the multiple data types. Here we construct a model for the joint distribution of bivariate continuous and ordinal outcomes by applying the concept of latent variables to a multivariate normal distribution. The approach is then extended to allow for clustering of the bivariate outcomes. The model can be parameterized in a way that allows writing the joint distribution as a product of a standard random effects model for the continuous variable and a correlated cumulative probit model for the ordinal outcome. This factorization suggests convenient parameter estimation using estimating equations. Foetal weight and malformation data from a developmental toxicity experiment illustrate the results.

  5. A bivariate ordered probit estimator with mixed effects

    OpenAIRE

    Buscha, Franz; Conte, Anna

    2010-01-01

    In this paper, we discuss the derivation and application of a bivariate ordered probit model with mixed effects. Our approach allows one to estimate the distribution of the effect (gamma) of an endogenous ordered variable on an ordered explanatory variable. By allowing gamma to vary over the population, our estimator offers a more flexible parametric setting to recover the causal effect of an endogenous variable in an ordered choice setting. We use Monte Carlo simulations to examine the perfo...

  6. Optimal number of upper order statistics used in estimation for the ...

    African Journals Online (AJOL)

    Beirlant et al. (2011) introduced a bias-reduced estimator for the coeffcient of tail dependence and for bivariate tail probability in bivariate extreme value statistics. In this paper, we are interested in the problem of choice of the number of extreme order statistics of bivariate observations exceeding high thresholds, we want to ...

  7. Bivariate Lagrange interpolation at the Padua points: Computational aspects

    Science.gov (United States)

    Caliari, Marco; de Marchi, Stefano; Vianello, Marco

    2008-11-01

    The so-called "Padua points" give a simple, geometric and explicit construction of bivariate polynomial interpolation in the square. Moreover, the associated Lebesgue constant has minimal order of growth . Here we show four families of Padua points for interpolation at any even or odd degree n, and we present a stable and efficient implementation of the corresponding Lagrange interpolation formula, based on the representation in a suitable orthogonal basis. We also discuss extension of (non-polynomial) Padua-like interpolation to other domains, such as triangles and ellipses; we give complexity and error estimates, and several numerical tests.

  8. Hypotonic versus isotonic maintenance fluids after surgery for children: a randomized controlled trial.

    Science.gov (United States)

    Choong, Karen; Arora, Steve; Cheng, Ji; Farrokhyar, Forough; Reddy, Desigen; Thabane, Lehana; Walton, J Mark

    2011-11-01

    The objective of this randomized controlled trial was to evaluate the risk of hyponatremia following administration of a isotonic (0.9% saline) compared to a hypotonic (0.45% saline) parenteral maintenance solution (PMS) for 48 hours to postoperative pediatric patients. Surgical patients 6 months to 16 years of age with an expected postoperative stay of >24 hours were eligible. Patients with an uncorrected baseline plasma sodium level abnormality, hemodynamic instability, chronic diuretic use, previous enrollment, and those for whom either hypotonic PMS or isotonic PMS was considered contraindicated or necessary, were excluded. A fully blinded randomized controlled trial was performed. The primary outcome was acute hyponatremia. Secondary outcomes included severe hyponatremia, hypernatremia, adverse events attributable to acute plasma sodium level changes, and antidiuretic hormone levels. A total of 258 patients were enrolled and assigned randomly to receive hypotonic PMS (N = 130) or isotonic PMS (N = 128). Baseline characteristics were similar for the 2 groups. Hypotonic PMS significantly increased the risk of hyponatremia, compared with isotonic PMS (40.8% vs 22.7%; relative risk: 1.82 [95% confidence interval: 1.21-2.74]; P = .004). Admission to the pediatric critical care unit was not an independent risk factor for the development of hyponatremia. Isotonic PMS did not increase the risk of hypernatremia (relative risk: 1.30 [95% confidence interval: 0.30-5.59]; P = .722). Antidiuretic hormone levels and adverse events were not significantly different between the groups. Isotonic PMS is significantly safer than hypotonic PMS in protecting against acute postoperative hyponatremia in children.

  9. Effects of isotonic and isometric exercises with mist sauna bathing on cardiovascular, thermoregulatory, and metabolic functions

    Science.gov (United States)

    Iwase, Satoshi; Kawahara, Yuko; Nishimura, Naoki; Nishimura, Rumiko; Sugenoya, Junichi; Miwa, Chihiro; Takada, Masumi

    2014-08-01

    To clarify the effects of isometric and isotonic exercise during mist sauna bathing on the cardiovascular function, thermoregulatory function, and metabolism, six healthy young men (22 ± 1 years old, height 173 ± 4 cm, weight 65.0 ± 5.0 kg) were exposed to a mist sauna for 10 min at a temperature of 40 °C, and relative humidity of 100 % while performing or not performing ˜30 W of isometric or isotonic exercise. The effect of the exercise was assessed by measuring tympanic temperature, heart rate, systolic and diastolic blood pressure, chest sweat rate, chest skin blood flow, and plasma catecholamine and cortisol, glucose, lactate, and free fatty acid levels. Repeated measures ANOVA showed no significant differences in blood pressure, skin blood flow, sweat rate, and total amount of sweating. Tympanic temperature increased more during isotonic exercise, and heart rate increase was more marked during isotonic exercise. The changes in lactate indicated that fatigue was not very great during isometric exercise. The glucose level indicated greater energy expenditure during isometric exercise. The free fatty acid and catecholamine levels indicated that isometric exercise did not result in very great energy expenditure and stress, respectively. The results for isotonic exercise of a decrease in lactate level and an increase in plasma free fatty acid level indicated that fatigue and energy expenditure were rather large while the perceived stress was comparatively low. We concluded that isotonic exercise may be a more desirable form of exercise during mist sauna bathing given the changes in glucose and free fatty acid levels.

  10. Effects of an isotonic beverage on autonomic regulation during and after exercise

    OpenAIRE

    Moreno Isadora Lessa; Pastre Carlos Marcelo; Ferreira Celso; de Abreu Luiz Carlos; Valenti Vitor Engrácia; Vanderlei Luiz Carlos Marques

    2013-01-01

    Abstract Background With prolonged physical activity, it is important to maintain adequate fluid balance. The impact of consuming isotonic drinks during and after exercise on the autonomic regulation of cardiac function is unclear. This study aimed to analyze the effects of consuming an isotonic drink on heart rate variability (HRV) during and after prolonged exercise. Methods Thirty-one young males (21.55 ± 1.89 yr) performed three different protocols (48 h interval between each stage): I) m...

  11. Comparison of Model Reliabilities from Single-Step and Bivariate Blending Methods

    DEFF Research Database (Denmark)

    Taskinen, Matti; Mäntysaari, Esa; Lidauer, Martin

    2013-01-01

    Model based reliabilities in genetic evaluation are compared between three methods: animal model BLUP, single-step BLUP, and bivariate blending after genomic BLUP. The original bivariate blending is revised in this work to better account animal models. The study data is extracted from the product......Model based reliabilities in genetic evaluation are compared between three methods: animal model BLUP, single-step BLUP, and bivariate blending after genomic BLUP. The original bivariate blending is revised in this work to better account animal models. The study data is extracted from...... be calculated. Model reliabilities by the single-step and the bivariate blending methods were higher than by animal model due to genomic information. Compared to the single-step method, the bivariate blending method reliability estimates were, in general, lower. Computationally bivariate blending method was......, on the other hand, lighter than the single-step method....

  12. Efficient estimation of semiparametric copula models for bivariate survival data

    KAUST Repository

    Cheng, Guang

    2014-01-01

    A semiparametric copula model for bivariate survival data is characterized by a parametric copula model of dependence and nonparametric models of two marginal survival functions. Efficient estimation for the semiparametric copula model has been recently studied for the complete data case. When the survival data are censored, semiparametric efficient estimation has only been considered for some specific copula models such as the Gaussian copulas. In this paper, we obtain the semiparametric efficiency bound and efficient estimation for general semiparametric copula models for possibly censored data. We construct an approximate maximum likelihood estimator by approximating the log baseline hazard functions with spline functions. We show that our estimates of the copula dependence parameter and the survival functions are asymptotically normal and efficient. Simple consistent covariance estimators are also provided. Numerical results are used to illustrate the finite sample performance of the proposed estimators. © 2013 Elsevier Inc.

  13. DESIGN OF BEZIER SPLINE SURFACES OVER BIVARIATE NETWORKS OF CURVES

    Directory of Open Access Journals (Sweden)

    A. P. Pobegailo

    2014-01-01

    Full Text Available The paper presents an approach to construct interpolating spline surfaces over a bivariate net-work of curves with rectangular patches. Patches of the interpolating spline surface are constructed by means of blending their boundaries with special polynomials. In order to ensure a necessary para-metric continuity of the designed surface the polynomials of the corresponding degree must be used. The constructed interpolating spline surfaces have a local shape control. If the surface frame is deter-mined by means of Bezier curves, then patches of the interpolating spline surface are Bezier surfaces. The presented approach to surface modeling can be used in such applications as computer graphics and geometric design.

  14. Bivariate analysis of floods in climate impact assessments.

    Science.gov (United States)

    Brunner, Manuela Irene; Sikorska, Anna E; Seibert, Jan

    2018-03-01

    Climate impact studies regarding floods usually focus on peak discharges and a bivariate assessment of peak discharges and hydrograph volumes is not commonly included. A joint consideration of peak discharges and hydrograph volumes, however, is crucial when assessing flood risks for current and future climate conditions. Here, we present a methodology to develop synthetic design hydrographs for future climate conditions that jointly consider peak discharges and hydrograph volumes. First, change factors are derived based on a regional climate model and are applied to observed precipitation and temperature time series. Second, the modified time series are fed into a calibrated hydrological model to simulate runoff time series for future conditions. Third, these time series are used to construct synthetic design hydrographs. The bivariate flood frequency analysis used in the construction of synthetic design hydrographs takes into account the dependence between peak discharges and hydrograph volumes, and represents the shape of the hydrograph. The latter is modeled using a probability density function while the dependence between the design variables peak discharge and hydrograph volume is modeled using a copula. We applied this approach to a set of eight mountainous catchments in Switzerland to construct catchment-specific and season-specific design hydrographs for a control and three scenario climates. Our work demonstrates that projected climate changes have an impact not only on peak discharges but also on hydrograph volumes and on hydrograph shapes both at an annual and at a seasonal scale. These changes are not necessarily proportional which implies that climate impact assessments on future floods should consider more flood characteristics than just flood peaks. Copyright © 2017. Published by Elsevier B.V.

  15. Coherent states associated with the wavefunctions and the spectrum of the isotonic oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Thirulogasanthar, K [Department of Mathematics and Statistics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6 (Canada); Saad, Nasser [Department of Mathematics and Statistics, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI, C1A 4P3 (Canada)

    2004-04-23

    Classes of coherent states are presented by replacing the labelling parameter z of Klauder-Perelomov type coherent states by confluent hypergeometric functions with specific parameters. Temporally stable coherent states for the isotonic oscillator Hamiltonian are presented and these states are identified as a particular case of the so-called Mittag-Leffler coherent states.

  16. A Comparison of Isotonic, Isokinetic, and Plyometric Training Methods for Vertical Jump Improvement.

    Science.gov (United States)

    Miller, Christine D.

    This annotated bibliography documents three training methods used to develop vertical jumping ability and power: isotonic, isokinetics, and plyometric training. Research findings on all three forms of training are summarized and compared. A synthesis of conclusions drawn from the annotated writings is presented. The report includes a glossary of…

  17. Acceptance of isotonic and hypotonic rehydrating beverages by athletes during training.

    Science.gov (United States)

    Décombaz, J; Gmünder, B; Daget, N; Munoz-Box, R; Howald, H

    1992-01-01

    This study compared the acceptance of two beverages (5% carbohydrate) of distinct osmolarities (hypotonic, 180 mOsm/kg and isotonic, 295 mOsm/kg) during the usual training practice of 97 athletes. A quantitative sensory profile by independent tasters ensured that organoleptic recognition would be unlikely during the tests. Each drink was consumed ad libitum during 3 different training sessions, at home. At each session, a subjective appreciation of hedonic and post-ingestive physiological effects (6 criteria) was obtained by means of a questionnaire. At the end of the experiment, the athletes were asked to express a preference for one of the "six" drinks. More athletes (blindly) chose the isotonic compared to the hypotonic drink (p = 0.03). This difference was not due intrinsically to the drinks, which the subjects were unable to distinguish on any of the criteria, but was related to certain aspects of the consumer's characteristics. Both groups had different drinking practices: the subjects choosing the isotonic beverage drank less before (p = 0.001) and more during (p = 0.013) the exercise. Age, sex, dimensions or type of physical activity (i.e. endurance vs speed/strength disciplines) were unrelated to the preference, except perhaps the duration of habitual exercise (p less than 0.05). We concluded that athletes, although unable to distinguish a hypotonic from an isotonic drink, may have specific habits and/or personal characteristics prompting them to favour one of them.

  18. Isotonic versus hypotonic maintenance IV fluids in hospitalized children: a meta-analysis.

    Science.gov (United States)

    Wang, Jingjing; Xu, Erdi; Xiao, Yanfeng

    2014-01-01

    To assess evidence from randomized controlled trials (RCTs) on the safety of isotonic versus hypotonic intravenous (IV) maintenance fluids in hospitalized children. We searched PubMed, Embase, Cochrane Library, and clinicaltrials.gov (up to April 11, 2013) for RCTs that compared isotonic to hypotonic maintenance IV fluid therapy in hospitalized children. Relative risk (RR), weighted mean differences, and 95% confidence intervals (CIs) were calculated based on the effects on plasma sodium (pNa). The risk of developing hyponatremia (pNa 145 mmol/L) was evaluated. We adopted a random-effects model in all meta-analyses. Sensitivity analyses by missing data were also performed. Ten RCTs were included in this review. The meta-analysis showed significantly higher risk of hypotonic IV fluids for developing hyponatremia (RR 2.24, 95% CI 1.52 to 3.31) and severe hyponatremia (RR 5.29, 95% CI 1.74 to 16.06). There was a significantly greater fall in pNa in children who received hypotonic IV fluids (-3.49 mmol/L versus isotonic IV fluids, 95% CI -5.63 to -1.35). No significant difference was found between the 2 interventions in the risk of hypernatremia (RR 0.73, 95% CI 0.22 to 2.48). None of the findings was sensitive to imputation of missing data. Isotonic fluids are safer than hypotonic fluids in hospitalized children requiring maintenance IV fluid therapy in terms of pNa.

  19. Isotonic versus hypotonic saline solution for maintenance intravenous fluid therapy in children: a systematic review.

    Science.gov (United States)

    Padua, April P; Macaraya, Josep Ryan G; Dans, Leonila F; Anacleto, Francisco E

    2015-07-01

    The administration of hypotonic saline solution for maintenance intravenous fluid (IVF) therapy has been the standard of care, but recent evidence has shown this treatment to be associated with hyponatremia-related complications. The aim of this systematic review was to determine which IVF, i.e., a hypotonic or an isotonic saline solution, poses less risk for the development of hyponatremia among hospitalized children who require maintenance IVF therapy. Medline, Cochrane Library, LILACS, Current Controlled Trials, reference lists, and abstract proceedings were searched for randomized controlled trials (RCTs) comparing hypotonic and isotonic saline solutions for maintenance IVF therapy in hospitalized children. Two reviewers independently assessed all potentially relevant studies and subsequently extracted data and evaluated the methodological quality of the RCTs. Studies were then combined and analyzed using a random effects model. Eleven RCTs met the inclusion criteria. Our analysis of these 11 RCTs showed that among hospitalized children receiving maintenance IVF therapy, isotonic solutions significantly decreased the risk of developing hyponatremia [relative risk (RR) 0.50, 95% confidence interval (CI) 0.40-0.62] without significantly increasing the risk for hypernatremia (RR 0.83, 95% CI 0.41-1.67). Current evidence does not support the standard practice of prescribing a hypotonic saline solution as maintenance IVF therapy to hospitalized children. Although there is no single IVF composition ideal for all children, an isotonic saline solution does appear to be the safer choice when maintenance IVF therapy is used in the general pediatric population.

  20. Coherent states associated to the wavefunctions and the spectrum of the isotonic oscillator

    OpenAIRE

    Thirulogasanthar, K.; Saad, Nasser

    2004-01-01

    Classes of coherent states are presented by replacing the labeling parameter $z$ of Klauder-Perelomov type coherent states by confluent hypergeometric functions with specific parameters. Temporally stable coherent states for the isotonic oscillator Hamiltonian are presented and these states are identified as a particular case of the so-called Mittag-Leffler coherent states.

  1. Comparison of isotonic and hypotonic intravenous maintenance fluids: a randomized clinical trial.

    Science.gov (United States)

    Friedman, Jeremy N; Beck, Carolyn E; DeGroot, Julie; Geary, Denis F; Sklansky, Daniel J; Freedman, Stephen B

    2015-05-01

    Use of hypotonic intravenous fluids for maintenance requirements is associated with increased risk of hyponatremia that results in morbidity and mortality in children. Clinical trial data comparing isotonic and hypotonic maintenance fluids in nonsurgical hospitalized pediatric patients outside intensive care units are lacking. To compare isotonic (sodium chloride, 0.9%, and dextrose, 5%) with hypotonic (sodium chloride, 0.45%, and dextrose, 5%) intravenous maintenance fluids in a hospitalized general pediatric population. In this double-blind randomized clinical trial,we recruited 110 children admitted to a general pediatric unit of a tertiary care children's hospital from March 1, 2008, through August 31, 2012 (age range, 1 month to 18 years), with normal baseline serum sodium levels who were anticipated to require intravenous maintenance fluids for 48 hours or longer (intent-to-treat analyses). Children with diagnoses that required specific fluid tonicity and volumes were excluded. Patients were randomized to receive isotonic or hypotonic intravenous fluid at maintenance rates for 48 hours. The primary outcome was mean serum sodium level at 48 hours. The secondary outcomes were mean sodium level at 24 hours, hyponatremia and hypernatremia, weight gain, hypertension, and edema. Confounding variables were included in multiple regression models. Post hoc analyses included change from baseline sodium level at 24 and 48 hours and subgroup analysis of children with primary respiratory diagnosis. Of 110 enrolled patients, 54 received isotonic fluids and 56 received hypotonic fluids. The mean (SD) sodium level at 48 hours was 139.9 (2.7) mEq/L in the isotonic group and 139.6 (2.6) mEq/L in the hypotonic group (95% CI of the difference, -0.94 to 1.74 mEq/L; P = .60). Two patients in the hypotonic group developed hyponatremia, 1 in each group developed hypernatremia, 2 in each group developed hypertension, and 2 in the isotonic group developed edema. Mean (SD

  2. Isotonic versus hypotonic solutions for maintenance intravenous fluid administration in children.

    Science.gov (United States)

    McNab, Sarah; Ware, Robert S; Neville, Kristen A; Choong, Karen; Coulthard, Mark G; Duke, Trevor; Davidson, Andrew; Dorofaeff, Tavey

    2014-12-18

    Maintenance intravenous fluids are frequently used in hospitalised children who cannot maintain adequate hydration through enteral intake. Traditionally used hypotonic fluids have been associated with hyponatraemia and subsequent morbidity and mortality. Use of isotonic fluid has been proposed to reduce complications. To establish and compare the risk of hyponatraemia by systematically reviewing studies where isotonic is compared with hypotonic intravenous fluid for maintenance purposes in children.Secondly, to compare the risk of hypernatraemia, the effect on mean serum sodium concentration and the rate of attributable adverse effects of both fluid types in children. We ran the search on 17 June 2013. We searched the Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE (OvidSP), Embase (OvidSP), and ISI Web of Science. We also searched clinical trials registers and screened reference lists. We updated this search in October 2014 but these results have not yet been incorporated. We included randomised controlled trials that compared isotonic versus hypotonic intravenous fluids for maintenance hydration in children. At least two authors assessed and extracted data for each trial. We presented dichotomous outcomes as risk ratios (RR) with 95% confidence intervals (CIs) and continuous outcomes as mean differences with 95% CIs. Ten studies met the inclusion criteria, with a total of 1106 patients. The majority of the studies were performed in surgical or intensive care populations (or both). There was considerable variation in the composition of intravenous fluid, particularly hypotonic fluid, used in the studies. There was a low risk of bias for most of the included studies. Ten studies provided data for our primary outcome, a total of 449 patients in the analysis received isotonic fluid, while 521 received hypotonic fluid. Those who received isotonic fluid had a substantially lower risk

  3. Different landslide sampling strategies in a grid-based bi-variate statistical susceptibility model

    Science.gov (United States)

    Hussin, Haydar Y.; Zumpano, Veronica; Reichenbach, Paola; Sterlacchini, Simone; Micu, Mihai; van Westen, Cees; Bălteanu, Dan

    2016-01-01

    This study had three aims. The first was to assess the performance of the weights-of-evidence (WofE) landslide susceptibility model in areas that are very different in terms of size, geoenvironmental settings, and landslide types. The second was to test the appropriate strategies to sample the mapped landslide polygon. The final aim was to evaluate the performance of the method to changes in the landslide sample size used to train the model. The method was applied to two areas: the Fella River basin (eastern Italian Alps) containing debris flows, and Buzau County (Romanian Carpathians) with shallow landslides. The three landslide sampling strategies used were: (1) the landslide scarp centroid, (2) points populating the scarp on a 50-m grid, and (3) the entire scarp polygon. The highest success rates were obtained when sampling shallow landslides as 50-m grid-points and debris flow scarps as polygons. Prediction rates were highest when using the entire scarp polygon method for both landslide types. The sample size test using the landslide centroids showed that a sample of 104 debris flow scarps was sufficient to predict the remaining 941 debris flows in the Fella River basin, while 161 shallow landslides was the minimum required number to predict the remaining 1451 scarps in Buzau County. Below these landslide sample thresholds, model performance was too low. However, using more landslides than the threshold produced a plateau effect with little to no increase in the model performance rates.

  4. Bivariate Genomic Footprinting Detects Changes in Transcription Factor Activity

    Directory of Open Access Journals (Sweden)

    Songjoon Baek

    2017-05-01

    Full Text Available In response to activating signals, transcription factors (TFs bind DNA and regulate gene expression. TF binding can be measured by protection of the bound sequence from DNase digestion (i.e., footprint. Here, we report that 80% of TF binding motifs do not show a measurable footprint, partly because of a variable cleavage pattern within the motif sequence. To more faithfully portray the effect of TFs on chromatin, we developed an algorithm that captures two TF-dependent effects on chromatin accessibility: footprinting and motif-flanking accessibility. The algorithm, termed bivariate genomic footprinting (BaGFoot, efficiently detects TF activity. BaGFoot is robust to different accessibility assays (DNase-seq, ATAC-seq, all examined peak-calling programs, and a variety of cut bias correction approaches. BaGFoot reliably predicts TF binding and provides valuable information regarding the TFs affecting chromatin accessibility in various biological systems and following various biological events, including in cases where an absolute footprint cannot be determined.

  5. Bivariate Genomic Footprinting Detects Changes in Transcription Factor Activity.

    Science.gov (United States)

    Baek, Songjoon; Goldstein, Ido; Hager, Gordon L

    2017-05-23

    In response to activating signals, transcription factors (TFs) bind DNA and regulate gene expression. TF binding can be measured by protection of the bound sequence from DNase digestion (i.e., footprint). Here, we report that 80% of TF binding motifs do not show a measurable footprint, partly because of a variable cleavage pattern within the motif sequence. To more faithfully portray the effect of TFs on chromatin, we developed an algorithm that captures two TF-dependent effects on chromatin accessibility: footprinting and motif-flanking accessibility. The algorithm, termed bivariate genomic footprinting (BaGFoot), efficiently detects TF activity. BaGFoot is robust to different accessibility assays (DNase-seq, ATAC-seq), all examined peak-calling programs, and a variety of cut bias correction approaches. BaGFoot reliably predicts TF binding and provides valuable information regarding the TFs affecting chromatin accessibility in various biological systems and following various biological events, including in cases where an absolute footprint cannot be determined. Published by Elsevier Inc.

  6. Bivariate Rainfall and Runoff Analysis Using Entropy and Copula Theories

    Directory of Open Access Journals (Sweden)

    Lan Zhang

    2012-09-01

    Full Text Available Multivariate hydrologic frequency analysis has been widely studied using: (1 commonly known joint distributions or copula functions with the assumption of univariate variables being independently identically distributed (I.I.D. random variables; or (2 directly applying the entropy theory-based framework. However, for the I.I.D. univariate random variable assumption, the univariate variable may be considered as independently distributed, but it may not be identically distributed; and secondly, the commonly applied Pearson’s coefficient of correlation (g is not able to capture the nonlinear dependence structure that usually exists. Thus, this study attempts to combine the copula theory with the entropy theory for bivariate rainfall and runoff analysis. The entropy theory is applied to derive the univariate rainfall and runoff distributions. It permits the incorporation of given or known information, codified in the form of constraints and results in a universal solution of univariate probability distributions. The copula theory is applied to determine the joint rainfall-runoff distribution. Application of the copula theory results in: (i the detection of the nonlinear dependence between the correlated random variables-rainfall and runoff, and (ii capturing the tail dependence for risk analysis through joint return period and conditional return period of rainfall and runoff. The methodology is validated using annual daily maximum rainfall and the corresponding daily runoff (discharge data collected from watersheds near Riesel, Texas (small agricultural experimental watersheds and Cuyahoga River watershed, Ohio.

  7. Epileptic seizure prediction based on a bivariate spectral power methodology.

    Science.gov (United States)

    Bandarabadi, Mojtaba; Teixeira, Cesar A; Direito, Bruno; Dourado, Antonio

    2012-01-01

    The spectral power of 5 frequently considered frequency bands (Alpha, Beta, Gamma, Theta and Delta) for 6 EEG channels is computed and then all the possible pairwise combinations among the 30 features set, are used to create a 435 dimensional feature space. Two new feature selection methods are introduced to choose the best candidate features among those and to reduce the dimensionality of this feature space. The selected features are then fed to Support Vector Machines (SVMs) that classify the cerebral state in preictal and non-preictal classes. The outputs of the SVM are regularized using a method that accounts for the classification dynamics of the preictal class, also known as "Firing Power" method. The results obtained using our feature selection approaches are compared with the ones obtained using minimum Redundancy Maximum Relevance (mRMR) feature selection method. The results in a group of 12 patients of the EPILEPSIAE database, containing 46 seizures and 787 hours multichannel recording for out-of-sample data, indicate the efficiency of the bivariate approach as well as the two new feature selection methods. The best results presented sensitivity of 76.09% (35 of 46 seizures predicted) and a false prediction rate of 0.15(-1).

  8. An adjustment to improve the bivariate survivor function repaired NPMLE.

    Science.gov (United States)

    Moodie, F Zoe; Prentic, Ross L

    2005-09-01

    We recently proposed a representation of the bivariate survivor function as a mapping of the hazard function for truncated failure time variates. The representation led to a class of estimators that includes van der Laan's repaired nonparametric maximum likelihood estimator (NPMLE) as an important special case. We proposed a Greenwood-like variance estimator for the repaired NPMLE but found somewhat poor agreement between the empirical variance estimates and these analytic estimates for the sample sizes and bandwidths considered in our simulation study. The simulation results also confirmed those of others in showing slightly inferior performance for the repaired NPMLE compared to other competing estimators as well as a sensitivity to bandwidth choice in moderate sized samples. Despite its attractive asymptotic properties, the repaired NPMLE has drawbacks that hinder its practical application. This paper presents a modification of the repaired NPMLE that improves its performance in moderate sized samples and renders it less sensitive to the choice of bandwidth. Along with this modified estimator, more extensive simulation studies of the repaired NPMLE and Greenwood-like variance estimates are presented. The methods are then applied to a real data example.

  9. A Bivariate Markov Regime Switching GARCH Approach to Estimate Time Varying Minimum Variance Hedge Ratios

    OpenAIRE

    Hsiang-Tai Lee; Jonathan Yoder

    2005-01-01

    This paper develops a new bivariate Markov regime switching BEKK-GARCH (RS-BEKK-GARCH) model. The model is a state-dependent bivariate BEKK- GARCH model, and an extension of Gray’s univariate generalized regime- switching (GRS) model to the bivariate case. To solve the path- dependency problem inherent in the bivariate regime switching BEKK-GARCH model, we propose a recombining method for the covariance term in the conditional variance-covariance matrix. The model is applied to estimate time-...

  10. Bivariate cumulative probit model for the comparison of neuronal encoding hypotheses.

    Science.gov (United States)

    Hillmann, Julia; Kneib, Thomas; Koepcke, Lena; Juárez Paz, León M; Kretzberg, Jutta

    2014-01-01

    Understanding the way stimulus properties are encoded in the nerve cell responses of sensory organs is one of the fundamental scientific questions in neurosciences. Different neuronal coding hypotheses can be compared by use of an inverse procedure called stimulus reconstruction. Here, based on different attributes of experimentally recorded neuronal responses, the values of certain stimulus properties are estimated by statistical classification methods. Comparison of stimulus reconstruction results then allows to draw conclusions about relative importance of covariate features. Since many stimulus properties have a natural order and can therefore be considered as ordinal, we introduce a bivariate ordinal probit model to obtain classifications for the combination of light intensity and velocity of a visual dot pattern based on different covariates extracted from recorded spike trains. For parameter estimation, we develop a Bayesian Gibbs sampler and incorporate penalized splines to model nonlinear effects. We compare the classification performance of different individual cell covariates and simple features of groups of neurons and find that the combination of at least two covariates increases the classification performance significantly. Furthermore, we obtain a non-linear effect for the first spike latency. The model is compared to a naïve Bayesian stimulus estimation method where it yields comparable misclassification rates for the given dataset. Hence, the bivariate ordinal probit model is shown to be a helpful tool for stimulus reconstruction particularly thanks to its flexibility with respect to the number of covariates as well as their scale and effect type. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Bivariate C^1 quadratic finite elements and vertex splines

    Science.gov (United States)

    Chui, Charles K.; He, Tian Xiao

    1990-01-01

    Following work of Heindl and of Powell and Sabin, each triangle of an arbitrary (regular) triangulation Δ of a polygonal region Ω in {R^2} is subdivided into twelve triangles, using the three medians, yielding the refinement hat Δ of Δ , so that {C^1} quadratic finite elements can be constructed. In this paper, we derive the Bezier nets of these elements in terms of the parameters that describe function and first partial derivative values at the vertices and values of the normal derivatives at the midpoints of the edges of Δ . Consequently, bivariate {C^1} quadratic (generalized) vertex splines on Δ have an explicit formulation. Here, a generalized vertex spline is one which is a piecewise polynomial on the refined grid partition hat Δ and has support that contains at most one vertex of the original partition Δ in its interior. The collection of all {C^1} quadratic generalized vertex splines on Δ so constructed is shown to form a basis of S_2^1(hat Δ ) , the vector space of all functions on {C^1}(Ω ) whose restrictions to each triangular cell of the partition hat Δ are quadratic polynomials. A subspace with the basis given by appropriately chosen generalized vertex splines with exactly one vertex of Δ in the interior of their supports, that reproduces all quadratic polynomials, is identified, and hence, has approximation order three. Quasi-interpolation formulas using this subspace are obtained. In addition, a constructive procedure that yields a locally supported basis of yet another subspace with dimension given by the number of vertices of Δ , that has approximation order three, is given.

  12. Synthetic control charts with two-stage sampling for monitoring bivariate processes

    Directory of Open Access Journals (Sweden)

    Antonio F. B. Costa

    2007-04-01

    Full Text Available In this article, we consider the synthetic control chart with two-stage sampling (SyTS chart to control bivariate processes. During the first stage, one item of the sample is inspected and two correlated quality characteristics (x;y are measured. If the Hotelling statistic T1² for these individual observations of (x;y is lower than a specified value UCL1 the sampling is interrupted. Otherwise, the sampling goes on to the second stage, where the remaining items are inspected and the Hotelling statistic T2² for the sample means of (x;y is computed. When the statistic T2² is larger than a specified value UCL2, the sample is classified as nonconforming. According to the synthetic control chart procedure, the signal is based on the number of conforming samples between two neighbor nonconforming samples. The proposed chart detects process disturbances faster than the bivariate charts with variable sample size and it is from the practical viewpoint more convenient to administer.Este artigo apresenta um gráfico de controle com regra especial de decisão e amostragens em dois estágios para o monitoramento de processos bivariados. No primeiro estágio, um item da amostra é inspecionado e duas características de qualidade correlacionadas (x;y são medidas. Se a estatística de Hotelling T1² para as observações individuais de (x;y for menor que um valor especificado UCL1 a amostragem é interrompida. Caso contrário, a amostragem segue para o segundo estágio, onde os demais itens da amostra são inspecionados e a estatística de Hotelling T2² para as médias de (x;y é calculada. Quando a estatística T2² é maior que um valor especificado UCL2, a amostra é classificada como não conforme. De acordo com a regra especial de decisão, o alarme é baseado no número de amostras entre duas não conformes. O gráfico proposto é mais ágil e mais simples do ponto de vista operacional que o gráfico de controle bivariado com tamanho de amostras variável.

  13. The lateral intercellular space as osmotic coupling compartment in isotonic transport

    DEFF Research Database (Denmark)

    Larsen, E.H.; Willumsen, N.J.; Mobjerg, N.

    2009-01-01

    coupling of water absorption to ion flow is energized by lateral Na+/K+ pumps. We show that the theory accounts quantitatively for steady- and time dependent states of solute-coupled fluid uptake by toad skin epithelium. Our experimental results exclude definitively three alternative theories of epithelial...... solute-water coupling: stoichiometric coupling at the molecular level by transport proteins like SGLT1, electro-osmosis and a 'junctional fluid transfer mechanism'. Convection-diffusion out of the lateral space constitutes the fundamental problem of isotonic transport by making the emerging fluid...... hypertonic relative to the fluid in the lateral intercellular space. In the Na+ recirculation theory the 'surplus of solutes' is returned to the lateral space via the cells energized by the lateral Na+/K+ pumps. We show that this theory accounts quantitatively for isotonic and hypotonic transport...

  14. Isotonic saline nasal irrigation is an effective adjunctive therapy to intranasal corticosteroid spray in allergic rhinitis.

    Science.gov (United States)

    Nguyen, Shaun A; Psaltis, Alkis J; Schlosser, Rodney J

    2014-01-01

    This study was designed to determine if the addition of large-volume, low-positive pressure nasal irrigations delivered with isotonic sodium chloride (hereinafter "saline") added to intranasal corticosteroid therapy improves quality of life and objective measures of nasal breathing in patients with allergic rhinitis when compared with intranasal corticosteroid alone. A prospective, unblinded, single-arm pilot study was performed of patients with allergic rhinitis already on intranasal corticosteroid pharmacotherapy. Patients added large-volume low-pressure saline irrigation twice daily for 8 weeks to their ongoing regiment of nasal corticosteroid. Mini-Rhinoconjunctivitis Quality of life Questionnaire (mRQLQ) assessment and nasal peak inspiratory flow (NPIF) were performed at baseline and at 4 and 8 weeks. A total of 40 patients were enrolled. Twice-daily nasal irrigation with isotonic saline significantly (p allergic rhinitis already on intranasal corticosteroid therapy. This study was a part of the clinical trial NCT01030146 registered at clinicaltrials.gov.

  15. A New Method for Obtaining the Baryons Mass under the Killingbeck Plus Isotonic Oscillator Potentials

    Directory of Open Access Journals (Sweden)

    Nasrin Salehi

    2016-01-01

    Full Text Available The spectrum of ground state and excited baryons (N, Δ, Λ, Σ, Ξ, and Ω particles has been investigated by using nonrelativistic quantum mechanics under the Killingbeck plus isotonic oscillator potentials. Using the Jacobi coordinates, anzast method, and generalized Gürsey Radicati (GR mass formula the three-body-wave equation is solved to calculate the different states of the considered baryons. A comparison between our calculations and the available experimental data shows that the position of the Roper resonances of the nucleon, the ground states, and the excited multiplets up to three GeV are in general well reproduced. Also one can conclude that the interaction between the quark constituents of baryon resonances could be described adequately by using the combination of Killingbeck and isotonic oscillator potentials form.

  16. Fluid transport and ion fluxes in mammalian kidney proximal tubule: a model analysis of isotonic transport

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Møbjerg, N.; Sørensen, J. N.

    2006-01-01

    'blocking' of apical water channels and in 'aquaporin-null' simulation. Reduced rate of volume reabsorption in AQP(-/-) mice would also require decreased apical sodium permeability. Paracellular convection accounts for approx. 36% of the net Na+ absorption, and the model epithelium accomplishes uphill water...... simulates major physiological features of proximal tubule, including significantly lower water permeability of the AQP1-null preparation, and a ratio of net sodium uptake and oxygen consumption exceeding that predicted from stoichiometry of the Na+/K+-pump. Physical properties of interspace basement......Aim: By mathematical modelling, we analyse conditions for near-isotonic and isotonic transport by mammalian kidney proximal tubule. Methods: The model comprises compliant lateral intercellular space (lis) and cells, and infinitely large luminal and peritubular compartments with diffusible species...

  17. Fluid transport and ion fluxes in mammalian kidney proximal tubule: a model analysis of isotonic transport

    DEFF Research Database (Denmark)

    Larsen, E.H.; Møbjerg, N.; Sørensen, Jens Nørkær

    2006-01-01

    'blocking' of apical water channels and in 'aquaporin-null' simulation. Reduced rate of volume reabsorption in AQP(-/-) mice would also require decreased apical sodium permeability. Paracellular convection accounts for approx. 36% of the net Na+ absorption, and the model epithelium accomplishes uphill water...... simulates major physiological features of proximal tubule, including significantly lower water permeability of the AQP1-null preparation, and a ratio of net sodium uptake and oxygen consumption exceeding that predicted from stoichiometry of the Na+/K+-pump. Physical properties of interspace basement......Aim: By mathematical modelling, we analyse conditions for near-isotonic and isotonic transport by mammalian kidney proximal tubule. Methods: The model comprises compliant lateral intercellular space (lis) and cells, and infinitely large luminal and peritubular compartments with diffusible species...

  18. Attenuated fatigue in slow twitch skeletal muscle during isotonic exercise in rats with chronic heart failure.

    Directory of Open Access Journals (Sweden)

    Morten Munkvik

    Full Text Available During isometric contractions, slow twitch soleus muscles (SOL from rats with chronic heart failure (chf are more fatigable than those of sham animals. However, a muscle normally shortens during activity and fatigue development is highly task dependent. Therefore, we examined the development of skeletal muscle fatigue during shortening (isotonic contractions in chf and sham-operated rats. Six weeks following coronary artery ligation, infarcted animals were classified as failing (chf if left ventricle end diastolic pressure was >15 mmHg. During isoflurane anaesthesia, SOL with intact blood supply was stimulated (1s on 1s off at 30 Hz for 15 min and allowed to shorten isotonically against a constant afterload. Muscle temperature was maintained at 37°C. In resting muscle, maximum isometric force (F(max and the concentrations of ATP and CrP were not different in the two groups. During stimulation, F(max and the concentrations declined in parallel sham and chf. Fatigue, which was evident as reduced shortening during stimulation, was also not different in the two groups. The isometric force decline was fitted to a bi-exponential decay equation. Both time constants increased transiently and returned to initial values after approximately 200 s of the fatigue protocol. This resulted in a transient rise in baseline tension between stimulations, although this effect which was less prominent in chf than sham. Myosin light chain 2s phosphorylation declined in both groups after 100 s of isotonic contractions, and remained at this level throughout 15 min of stimulation. In spite of higher energy demand during isotonic than isometric contractions, both shortening capacity and rate of isometric force decline were as well or better preserved in fatigued SOL from chf rats than in sham. This observation is in striking contrast to previous reports which have employed isometric contractions to induce fatigue.

  19. A randomized controlled trial of isotonic versus hypotonic maintenance intravenous fluids in hospitalized children.

    Science.gov (United States)

    Saba, Thomas G; Fairbairn, James; Houghton, Fiona; Laforte, Diane; Foster, Bethany J

    2011-09-23

    Isotonic saline has been proposed as a safer alternative to traditional hypotonic solutions for intravenous (IV) maintenance fluids to prevent hyponatremia. However, the optimal tonicity of maintenance intravenous fluids in hospitalized children has not been determined. The objective of this study was to estimate and compare the rates of change in serum sodium ([Na]) for patients administered either hypotonic or isotonic IV fluids for maintenance needs. This was a masked controlled trial. Randomization was stratified by admission type: medical patients and post-operative surgical patients, aged 3 months to 18 years, who required IV fluids for at least 8 hours. Patients were randomized to receive either 0.45% or 0.9% saline in 5.0% dextrose. Treating physicians used the study fluid for maintenance; infusion rate and the use of additional fluids were left to their discretion. Sixteen children were randomized to 0.9% saline and 21 to 0.45% saline. Baseline characteristics, duration (average of 12 hours) and rate of study fluid infusion, and the volume of additional isotonic fluids given were similar for the two groups. [Na] increased significantly in the 0.9% group (+0.20 mmol/L/h [IQR +0.03, +0.4]; P = 0.02) and increased, but not significantly, in the 0.45% group (+0.08 mmol/L/h [IQR -0.15, +0.16]; P = 0.07). The rate of change and absolute change in serum [Na] did not differ significantly between groups. When administered at the appropriate maintenance rate and accompanied by adequate volume expansion with isotonic fluids, 0.45% saline did not result in a drop in serum sodium during the first 12 hours of fluid therapy in children without severe baseline hyponatremia. Confirmation in a larger study is strongly recommended. NCT00457873 (http://www.clinicaltrials.gov/).

  20. Hypotonic versus isotonic fluids in hospitalized children: a systematic review and meta-analysis.

    Science.gov (United States)

    Foster, Byron Alexander; Tom, Dina; Hill, Vanessa

    2014-07-01

    To determine whether the use of hypotonic vs isotonic maintenance fluids confers an increased risk of hyponatremia in hospitalized children. A search of MEDLINE (1946 to January 2013), the Cochrane Central Registry (1991 to December 2012), Cumulative Index for Nursing and Allied Health Literature (1990 to December 2012), and Pediatric Academic Societies (2000-2012) abstracts was conducted using the terms "hypotonic fluids/saline/solutions" and "isotonic fluids/saline/solutions," and citations were reviewed using a predefined protocol. Data on the primary and secondary outcomes were extracted from original articles by 2 authors independently. Meta-analyses of the primary and secondary outcomes were performed when possible. A total of 1634 citations were screened. Ten studies (n = 893) identified as independent randomized controlled trials were included. Five studies examined subjects in the intensive care unit setting, including 4 on regular wards and 1 in a mixed setting. In hospitalized children receiving maintenance intravenous fluids, hyponatremia was seen more often in those receiving hypotonic fluids than in those receiving isotonic fluids, with an overall relative risk of 2.37 (95% CI, 1.72-3.26). Receipt of hypotonic fluids was associated with a relative risk of moderate hyponatremia (hypotonic fluids with half-normal saline found a relative risk of hyponatremia of 2.42 (95% CI, 1.32-4.45). In hospitalized children in intensive care and postoperative settings, the administration of hypotonic maintenance fluids increases the risk of hyponatremia when compared with administration of isotonic fluids. For patients on general wards, insufficient data are available based on the reviewed studies, and individual risk factors must be assessed. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. A randomized controlled trial of isotonic versus hypotonic maintenance intravenous fluids in hospitalized children

    Directory of Open Access Journals (Sweden)

    Laforte Diane

    2011-09-01

    Full Text Available Abstract Background Isotonic saline has been proposed as a safer alternative to traditional hypotonic solutions for intravenous (IV maintenance fluids to prevent hyponatremia. However, the optimal tonicity of maintenance intravenous fluids in hospitalized children has not been determined. The objective of this study was to estimate and compare the rates of change in serum sodium ([Na] for patients administered either hypotonic or isotonic IV fluids for maintenance needs. Methods This was a masked controlled trial. Randomization was stratified by admission type: medical patients and post-operative surgical patients, aged 3 months to 18 years, who required IV fluids for at least 8 hours. Patients were randomized to receive either 0.45% or 0.9% saline in 5.0% dextrose. Treating physicians used the study fluid for maintenance; infusion rate and the use of additional fluids were left to their discretion. Results Sixteen children were randomized to 0.9% saline and 21 to 0.45% saline. Baseline characteristics, duration (average of 12 hours and rate of study fluid infusion, and the volume of additional isotonic fluids given were similar for the two groups. [Na] increased significantly in the 0.9% group (+0.20 mmol/L/h [IQR +0.03, +0.4]; P = 0.02 and increased, but not significantly, in the 0.45% group (+0.08 mmol/L/h [IQR -0.15, +0.16]; P = 0.07. The rate of change and absolute change in serum [Na] did not differ significantly between groups. Conclusions When administered at the appropriate maintenance rate and accompanied by adequate volume expansion with isotonic fluids, 0.45% saline did not result in a drop in serum sodium during the first 12 hours of fluid therapy in children without severe baseline hyponatremia. Confirmation in a larger study is strongly recommended. Clinical Trial Registration Number NCT00457873 (http://www.clinicaltrials.gov/

  2. Decay properties of charm and bottom mesons in a quantum isotonic nonlinear oscillator potential model

    Energy Technology Data Exchange (ETDEWEB)

    Rahmani, S.; Hassanabadi, H. [Shahrood University of Technology, Physics Department, Shahrood (Iran, Islamic Republic of)

    2017-09-15

    Employing generalized quantum isotonic oscillator potential we determine wave function for mesonic system in nonrelativistic formalism. Then we investigate branching ratios of leptonic decays for heavy-light mesons including a charm quark. Next, by applying the Isgur-Wise function we obtain branching ratios of semileptonic decays for mesons including a bottom quark. The weak decay of the B{sub c} meson is also analyzed to study the life time. Comparison with other available theoretical approaches is presented. (orig.)

  3. The effects of K+ channel blockade on eccentric and isotonic twitch and fatiguing contractions in situ

    Directory of Open Access Journals (Sweden)

    Michelle eMoyer

    2012-09-01

    Full Text Available K+ channel blockers like 3,4-diaminopyridine (DAP can double isometric muscle force. Functional movements require more complex concentric and eccentric contractions, however the effects of K+ channel blockade on these types of contractions in situ are unknown. Extensor digitorum longus (EDL muscles were stimulated in situ with and without DAP in anesthetized rats and fatigability was addressed using a series of either concentric or eccentric contractions. During isotonic protocols (5-100% load, DAP significantly shifted shortening- and maximum shortening velocity-load curves upward and to the right and increased power and work. Maximum shortening, maximum shortening velocity and power doubled while work increased by approximately 250% during isotonic contraction at 50% load. During isotonic fatigue, DAP significantly augmented maximum shortening, work, shortening velocity and power. During constant velocity eccentric protocols (2-12 mm/s, DAP increased muscle force during eccentric contractions at 6, 8, 10 and 12 mm/s. During eccentric contraction at a constant velocity of 6mm/s while varying the stimulation frequency, DAP significantly increased muscle force during 20, 40 and 70 Hz . The effects of DAP on muscle contractile performance during eccentric fatigue varied with level of fatigue. DAP-induced contractile increases during isotonic contractions were similar to those produced during previously studied isometric contractions, while the DAP effect during eccentric contractions was more modest. These findings are especially important in attempting to optimize functional electrical stimulation parameters for spinal cord injury patients while also preventing rapid fatigue of those muscles.

  4. Comparison of complex permittivities of isotonic colloids containing single-wall carbon nanotubes of varying chirality.

    Science.gov (United States)

    Nair, Tejas; Symanowski, James T; Gach, H Michael

    2012-02-01

    The application of bio-compatible, conductive nanoparticles in combination with radiofrequency (RF) irradiation to raise tissue temperatures between 40 and 60 °C for hyperthermia and ablation spurred interest in the complex permittivities of isotonic nanoparticle-based colloids. Nanoparticles with large aspect ratios and high permittivities increase the bulk permittivity of the colloid and RF losses at the macroscopic scale. The complex permittivities of isotonic colloids with and without single-wall carbon nanotubes (SWCNTs) containing either metallic, semiconducting, or mixed chiralities were measured from 20 MHz to 1 GHz at room temperature. The colloids were made with one of three different isotonic solvents: phosphate buffered saline (PBS), and Dulbecco's modified eagle medium (DMEM) with and without 0.5% weight/volume bovine serum albumin to simulate cytosol and blood, respectively. The concentration of elemental carbon from the SWCNTs in the colloids ranged from 16 to 17 mM. The permittivities were corrected for electrode polarization effects by fitting the data to the Cole-Cole relaxation model with a constant phase angle element. The presence of SWCNTs increased both the real and imaginary components of the permittivities of the colloids. For all three solvents, the direct current (DC) components of the real and imaginary permittivities were greatest for the colloids containing the mixed chirality SWCNTs, followed by the colloids with semiconducting SWCNTs, and then metallic SWCNTs. Copyright © 2011 Wiley Periodicals, Inc.

  5. Improvement of diaphragm and limb muscle isotonic contractile performance by K+ channel blockade

    Directory of Open Access Journals (Sweden)

    Pollarine Jennifer

    2010-01-01

    Full Text Available Abstract The K+ channel blocking aminopyridines greatly improve skeletal muscle isometric contractile performance during low to intermediate stimulation frequencies, making them potentially useful as inotropic agents for functional neuromuscular stimulation applications. Most restorative applications involve muscle shortening; however, previous studies on the effects of aminopyridines have involved muscle being held at constant length. Isotonic contractions differ substantially from isometric contractions at a cellular level with regards to factors such as cross-bridge formation and energetic requirements. The present study tested effects of 3,4-diaminopyridine (DAP on isotonic contractile performance of diaphragm, extensor digitorum longus (EDL and soleus muscles from rats. During contractions elicited during 20 Hz stimulation, DAP improved work over a range of loads for all three muscles. In contrast, peak power was augmented for the diaphragm and EDL but not the soleus. Maintenance of increased work and peak power was tested during repetitive fatigue-inducing stimulation using a single load of 40% and a stimulation frequency of 20 Hz. Work and peak power of both diaphragm and EDL were augmented by DAP for considerable periods of time, whereas that of soleus muscle was not affected significantly. These results demonstrate that DAP greatly improves both work and peak power of the diaphragm and EDL muscle during isotonic contractions, which combined with previous data on isometric contractions indicates that this agent is suitable for enhancing muscle performance during a range of contractile modalities.

  6. Effects of an isotonic beverage on autonomic regulation during and after exercise

    Directory of Open Access Journals (Sweden)

    Moreno Isadora Lessa

    2013-01-01

    Full Text Available Abstract Background With prolonged physical activity, it is important to maintain adequate fluid balance. The impact of consuming isotonic drinks during and after exercise on the autonomic regulation of cardiac function is unclear. This study aimed to analyze the effects of consuming an isotonic drink on heart rate variability (HRV during and after prolonged exercise. Methods Thirty-one young males (21.55 ± 1.89 yr performed three different protocols (48 h interval between each stage: I maximal exercise test to determine the load for the protocols; II Control protocol (CP and; III. Experimental protocol (EP. The protocols consisted of 10 min at rest with the subject in the supine position, 90 min of treadmill exercise (60% of VO2 peak and 60 min of rest placed in the dorsal decubitus position. No rehydration beverage consumption was allowed during CP. During EP, however, the subjects were given an isotonic solution (Gatorade, Brazil containing carbohydrate (30 g, sodium (225 mg, chloride (210 mg and potassium (60 mg per 500 ml of the drink. For analysis of HRV data, time and frequency domain indices were investigated. HRV was recorded at rest (5–10 min, during exercise (25–30 min, 55–60 min and 85–90 min and post-exercise (5–10 min, 15–20 min, 25–30 min, 40–45 min and 55–60 min. Results Regardless of hydration, alterations in the SNS and PSNS were observed, revealing an increase in the former and a decrease in the latter. Hydrating with isotonic solution during recovery induced significant changes in cardiac autonomic modulation, promoting faster recovery of linear HRV indices. Conclusion Hydration with isotonic solution did not significantly influence HRV during exercise; however, after exercise it promoted faster recovery of linear indices.

  7. Effects of an isotonic beverage on autonomic regulation during and after exercise.

    Science.gov (United States)

    Moreno, Isadora Lessa; Pastre, Carlos Marcelo; Ferreira, Celso; de Abreu, Luiz Carlos; Valenti, Vitor Engrácia; Vanderlei, Luiz Carlos Marques

    2013-01-04

    With prolonged physical activity, it is important to maintain adequate fluid balance. The impact of consuming isotonic drinks during and after exercise on the autonomic regulation of cardiac function is unclear. This study aimed to analyze the effects of consuming an isotonic drink on heart rate variability (HRV) during and after prolonged exercise. Thirty-one young males (21.55 ± 1.89 yr) performed three different protocols (48 h interval between each stage): I) maximal exercise test to determine the load for the protocols; II) Control protocol (CP) and; III). Experimental protocol (EP). The protocols consisted of 10 min at rest with the subject in the supine position, 90 min of treadmill exercise (60% of VO2 peak) and 60 min of rest placed in the dorsal decubitus position. No rehydration beverage consumption was allowed during CP. During EP, however, the subjects were given an isotonic solution (Gatorade, Brazil) containing carbohydrate (30 g), sodium (225 mg), chloride (210 mg) and potassium (60 mg) per 500 ml of the drink. For analysis of HRV data, time and frequency domain indices were investigated. HRV was recorded at rest (5-10 min), during exercise (25-30 min, 55-60 min and 85-90 min) and post-exercise (5-10 min, 15-20 min, 25-30 min, 40-45 min and 55-60 min). Regardless of hydration, alterations in the SNS and PSNS were observed, revealing an increase in the former and a decrease in the latter. Hydrating with isotonic solution during recovery induced significant changes in cardiac autonomic modulation, promoting faster recovery of linear HRV indices. Hydration with isotonic solution did not significantly influence HRV during exercise; however, after exercise it promoted faster recovery of linear indices.

  8. Interpreting Bivariate Regression Coefficients: Going beyond the Average

    Science.gov (United States)

    Halcoussis, Dennis; Phillips, G. Michael

    2010-01-01

    Statistics, econometrics, investment analysis, and data analysis classes often review the calculation of several types of averages, including the arithmetic mean, geometric mean, harmonic mean, and various weighted averages. This note shows how each of these can be computed using a basic regression framework. By recognizing when a regression model…

  9. A semiparametric bivariate probit model for joint modeling of outcomes in STEMI patients.

    Science.gov (United States)

    Ieva, Francesca; Marra, Giampiero; Paganoni, Anna Maria; Radice, Rosalba

    2014-01-01

    In this work we analyse the relationship among in-hospital mortality and a treatment effectiveness outcome in patients affected by ST-Elevation myocardial infarction. The main idea is to carry out a joint modeling of the two outcomes applying a Semiparametric Bivariate Probit Model to data arising from a clinical registry called STEMI Archive. A realistic quantification of the relationship between outcomes can be problematic for several reasons. First, latent factors associated with hospitals organization can affect the treatment efficacy and/or interact with patient's condition at admission time. Moreover, they can also directly influence the mortality outcome. Such factors can be hardly measurable. Thus, the use of classical estimation methods will clearly result in inconsistent or biased parameter estimates. Secondly, covariate-outcomes relationships can exhibit nonlinear patterns. Provided that proper statistical methods for model fitting in such framework are available, it is possible to employ a simultaneous estimation approach to account for unobservable confounders. Such a framework can also provide flexible covariate structures and model the whole conditional distribution of the response.

  10. Effects of three heavy metals on the bacteria growth kinetics. A bivariate model for toxicological assessment

    Energy Technology Data Exchange (ETDEWEB)

    Rial, Diego; Vazquez, Jose Antonio; Murado, Miguel Anxo [Instituto de Investigacions Marinas (CSIC), Vigo (ES). Grupo de Reciclado y Valorizacion de Materiales Residuales (REVAL)

    2011-05-15

    The effects of three heavy metals (Co, Ni and Cd) on the growth kinetics of five bacterial strains with different characteristics (Pseudomonas sp., Phaeobacter sp. strain 27-4, Listonella anguillarum, Carnobacterium piscicola and Leuconostoc mesenteroides subsp. lysis) were studied in a batch system. A bivariate model, function of time and dose, is proposed to describe simultaneously all the kinetic profiles obtained by incubating a microorganism at increasing concentrations of individual metals. This model combines the logistic equation for describing growth, with a modification of the cumulative Weibull's function for describing the dose-dependent variations of growth parameters. The comprehensive model thus obtained - which minimizes the effects of the experimental error - was statistically significant in all the studied cases, and it raises doubts about toxicological evaluations that are based on a single growth parameter, especially if it is not obtained from a kinetic equation. In lactic acid bacteria cultures (C. piscicola and L. mesenteroides), Cd induced remarkable differences in yield and time course of characteristic metabolites. A global parameter is defined (ED{sub 50,{tau}}: dose of toxic chemical that reduces the biomass of a culture by 50% compared to that produced by the control at the time corresponding to its semi maximum biomass) that allows comparing toxic effects on growth kinetics using a single value. (orig.)

  11. Accommodating negative intracluster correlation with a mixed effects logistic model for bivariate binary data.

    Science.gov (United States)

    Ten Have, T R; Kunselman, A; Zharichenko, E

    1998-03-01

    We extend the random intercept logistic model to accommodate negative intracluster correlations for bivariate binary response data. This approach assumes a single random effect per cluster, but entails separate affine transformations of this random effect for the two responses of the pair. We show this approach works for two data sets and a simulation, whereas other mixed effects approaches fail. The two data sets are from a crossover trial and a developmental toxicity study of the effects of chemical exposure on malformation risk among rat pups. Comparisons are made with the conditional likelihood approach and with generalized estimating equations estimation of the population-averaged logit model. Simulations show the conditional likelihood approach does not perform well for moderate to strong negative correlations, as a positive intracluster correlation is assumed. The proposed mixed effects approach appears to be slightly more conservative than the population-averaged approach with respect to coverage of confidence intervals. Nonetheless, the statistical literature suggests that mixed effects models provide information in addition to that provided by population-averaged models under scientific contexts such as crossover trials. Extensions to trivariate and higher-dimensional responses also are addressed. However, such extensions require certain constraints on the correlation structure.

  12. Bivariate spatial analysis of temperature and precipitation from general circulation models and observation proxies

    KAUST Repository

    Philbin, R.

    2015-05-22

    This study validates the near-surface temperature and precipitation output from decadal runs of eight atmospheric ocean general circulation models (AOGCMs) against observational proxy data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis temperatures and Global Precipitation Climatology Project (GPCP) precipitation data. We model the joint distribution of these two fields with a parsimonious bivariate Matérn spatial covariance model, accounting for the two fields\\' spatial cross-correlation as well as their own smoothnesses. We fit output from each AOGCM (30-year seasonal averages from 1981 to 2010) to a statistical model on each of 21 land regions. Both variance and smoothness values agree for both fields over all latitude bands except southern mid-latitudes. Our results imply that temperature fields have smaller smoothness coefficients than precipitation fields, while both have decreasing smoothness coefficients with increasing latitude. Models predict fields with smaller smoothness coefficients than observational proxy data for the tropics. The estimated spatial cross-correlations of these two fields, however, are quite different for most GCMs in mid-latitudes. Model correlation estimates agree well with those for observational proxy data for Australia, at high northern latitudes across North America, Europe and Asia, as well as across the Sahara, India, and Southeast Asia, but elsewhere, little consistent agreement exists.

  13. A Distribution-Based Multiple Imputation Method for Handling Bivariate Pesticide Data with Values below the Limit of Detection

    Science.gov (United States)

    Chen, Haiying; Quandt, Sara A.; Grzywacz, Joseph G.; Arcury, Thomas A.

    2011-01-01

    Background Environmental and biomedical researchers frequently encounter laboratory data constrained by a lower limit of detection (LOD). Commonly used methods to address these left-censored data, such as simple substitution of a constant for all values LOD, may bias parameter estimation. In contrast, multiple imputation (MI) methods yield valid and robust parameter estimates and explicit imputed values for variables that can be analyzed as outcomes or predictors. Objective In this article we expand distribution-based MI methods for left-censored data to a bivariate setting, specifically, a longitudinal study with biological measures at two points in time. Methods We have presented the likelihood function for a bivariate normal distribution taking into account values LOD as well as missing data assumed missing at random, and we use the estimated distributional parameters to impute values LOD and to generate multiple plausible data sets for analysis by standard statistical methods. We conducted a simulation study to evaluate the sampling properties of the estimators, and we illustrate a practical application using data from the Community Participatory Approach to Measuring Farmworker Pesticide Exposure (PACE3) study to estimate associations between urinary acephate (APE) concentrations (indicating pesticide exposure) at two points in time and self-reported symptoms. Results Simulation study results demonstrated that imputed and observed values together were consistent with the assumed and estimated underlying distribution. Our analysis of PACE3 data using MI to impute APE values LOD showed that urinary APE concentration was significantly associated with potential pesticide poisoning symptoms. Results based on simple substitution methods were substantially different from those based on the MI method. Conclusions The distribution-based MI method is a valid and feasible approach to analyze bivariate data with values LOD, especially when explicit values for the

  14. A Bivariate Mixture Model for Natural Antibody Levels to Human Papillomavirus Types 16 and 18: Baseline Estimates for Monitoring the Herd Effects of Immunization

    OpenAIRE

    Vink, Margaretha A.; Berkhof, Johannes; van de Kassteele, Jan; van Boven, Michiel; Bogaards, Johannes A

    2016-01-01

    Post-vaccine monitoring programs for human papillomavirus (HPV) have been introduced in many countries, but HPV serology is still an underutilized tool, partly owing to the weak antibody response to HPV infection. Changes in antibody levels among non-vaccinated individuals could be employed to monitor herd effects of immunization against HPV vaccine types 16 and 18, but inference requires an appropriate statistical model. The authors developed a four-component bivariate mixture model for join...

  15. Viscosity reduction of isotonic solutions of the photosensitizer TPCS2aby cyclodextrin complexation.

    Science.gov (United States)

    Tovsen, Marianne Lilletvedt; Tho, Ingunn; Tønnesen, Hanne Hjorth

    2018-02-01

    Meso-tetraphenyl chlorin disulphonate (TPCS 2a ) is a photosensitizer (PS) particularly developed and patented for use in the technology of photochemical internalization (PCI) against cancer. TPCS 2a is known to aggregate in aqueous media even at low concentrations (≥0.1 µM) and to form a high-viscosity network at clinically relevant concentrations (mM). The aim of this work was to evaluate the effect of two hydroxypropylated cyclodextrin derivatives of beta and gamma type, respectively i.e. HPβCD and HPγCD, on the aggregation and solubilization of TPCS 2a in isotonic solutions. Samples containing micromolar concentrations of TPCS 2a were studied spectrophotometrically, while samples containing a clinical relevant concentration (10 mM = 9 mg/ml) of TPCS 2a were evaluated by dynamic viscosity measurements. HPβCD was determined to be a more suitable solubilizer of TPCS 2a than HPγCD in aqueous media both in the absence and presence of salt. The complexation stoichiometry between TPCS 2a /HPβCD at micromolar to millimolar concentrations of TPCS 2a was determined to be 1:3 and 1:2 in the absence and presence of isotonic NaCl, respectively. The network of TPCS 2a (10 mM) was broken down in the presence of 3% w/v (= 20 mM) HPβCD, i.e. a 1:2 molar ratio between TPCS 2a and the cyclodextrin. Formation of the inclusion complex resulted in low viscosity samples both in water and in the presence of isotonic NaCl or phosphate buffered saline (PBS) at 25 °C and 37 °C.

  16. A prospective trial comparing isotonic with hypotonic maintenance fluids for prevention of hospital-acquired hyponatraemia.

    Science.gov (United States)

    Flores Robles, Claudia Montserrat; Cuello García, Carlos Alberto

    2016-08-01

    Recent literature suggests that hypotonic fluids increase the risk of hospital-acquired hyponatraemia; despite this, hypotonic fluids are widely used. To compare the change in serum sodium following the use of hypotonic (0.3% saline, 0.45% saline) or isotonic (0.9% saline) intravenous (IV) maintenance solutions in hospitalised children. This was a randomised controlled trial. Children aged 3 months to 15 years with medical or surgical disorders were randomised to receive one of three maintenance IV fluids: two hypotonic solutions (3.3% dextrose in 0.3% saline or 5% dextrose in 0.45% saline) and one isotonic solution (5% dextrose in 0.9% saline). The primary outcome was serum sodium levels at 8 hours. Secondary outcomes included the incidence of hospital-acquired hyponatraemia, adverse events attributable to IV solutions and length of hospital stay. 151 children were assigned randomly to receive 0.3% saline (n = 49), 0.45% saline (n = 50) or 0.9% saline (n = 52). Baseline characteristics were similar for the three groups. At 8 hours, mean (SD) serum sodium was lower in the hypotonic solutions groups [0.3% saline 134.65 (1.9) mmol/L, 0.45% saline 134.90 (2.3) mmol/L than 0.9% saline 137.98 (2.8) mmol/L] (P hypotonic groups [0.3% saline 10/49 (20.4%), 0.45% saline 11/50 (22%) than 0.9% saline 1/52 (1.9%), P = 0.006). There were no differences in other adverse effects or length of hospital stay between the groups. Hypotonic IV solutions increase the incidence of hospital-acquired hyponatraemia. Isotonic solutions are a safer alternative.

  17. Semiparametric Maximum Likelihood Estimation in Normal Transformation Models for Bivariate Survival Data

    Science.gov (United States)

    Li, Yi; Prentice, Ross L.; Lin, Xihong

    2008-01-01

    SUMMARY We consider a class of semiparametric normal transformation models for right censored bivariate failure times. Nonparametric hazard rate models are transformed to a standard normal model and a joint normal distribution is assumed for the bivariate vector of transformed variates. A semiparametric maximum likelihood estimation procedure is developed for estimating the marginal survival distribution and the pairwise correlation parameters. This produces an efficient estimator of the correlation parameter of the semiparametric normal transformation model, which characterizes the bivariate dependence of bivariate survival outcomes. In addition, a simple positive-mass-redistribution algorithm can be used to implement the estimation procedures. Since the likelihood function involves infinite-dimensional parameters, the empirical process theory is utilized to study the asymptotic properties of the proposed estimators, which are shown to be consistent, asymptotically normal and semiparametric efficient. A simple estimator for the variance of the estimates is also derived. The finite sample performance is evaluated via extensive simulations. PMID:19079778

  18. Semiparametric Maximum Likelihood Estimation in Normal Transformation Models for Bivariate Survival Data.

    Science.gov (United States)

    Li, Yi; Prentice, Ross L; Lin, Xihong

    2008-12-01

    We consider a class of semiparametric normal transformation models for right censored bivariate failure times. Nonparametric hazard rate models are transformed to a standard normal model and a joint normal distribution is assumed for the bivariate vector of transformed variates. A semiparametric maximum likelihood estimation procedure is developed for estimating the marginal survival distribution and the pairwise correlation parameters. This produces an efficient estimator of the correlation parameter of the semiparametric normal transformation model, which characterizes the bivariate dependence of bivariate survival outcomes. In addition, a simple positive-mass-redistribution algorithm can be used to implement the estimation procedures. Since the likelihood function involves infinite-dimensional parameters, the empirical process theory is utilized to study the asymptotic properties of the proposed estimators, which are shown to be consistent, asymptotically normal and semiparametric efficient. A simple estimator for the variance of the estimates is also derived. The finite sample performance is evaluated via extensive simulations.

  19. Dose-Finding Based on Bivariate Efficacy-Toxicity Outcome Using Archimedean Copula: e78805

    National Research Council Canada - National Science Library

    Yuxi Tao; Junlin Liu; Zhihui Li; Jinguan Lin; Tao Lu; Fangrong Yan

    2013-01-01

    ... constructed with Archimedean Copula, and extend the continual reassessment method (CRM) to a bivariate trial design in which the optimal dose for phase III is based on both efficacy and toxicity...

  20. Hypotonic versus isotonic maintenance intravenous fluid therapy in hospitalized children: a systematic review.

    Science.gov (United States)

    Beck, Carolyn E

    2007-11-01

    A systematic review of studies comparing hypotonic versus isotonic intravenous maintenance fluids in hospitalized children was conducted to determine whether hypotonic solutions increase the risk of acute hyponatremia. Studies were identified from electronic databases and hand-searched reference lists. A total of 283 abstracts were reviewed, 55 full-text articles were retrieved, and 3 studies were included. All studies were observational and were overall inconclusive. All authors cautioned against the routine use of hypotonic maintenance fluids, but hypotonic fluid administration did not always explain the development of acute hyponatremia. Further evidence is required as to the appropriate maintenance solution for hospitalized children.

  1. Phase II trial of isotonic fluid resuscitation in Kenyan children with severe malnutrition and hypovolaemia

    Directory of Open Access Journals (Sweden)

    Boga Mwanamvua

    2010-10-01

    Full Text Available Abstract Background Children with severe malnutrition who develop shock have a high mortality. Contrary to contemporaneous paediatric practice, current guidelines recommend use of low dose hypotonic fluid resuscitation (half-strength Darrows/5% dextrose (HSD/5D. We evaluated the safety and efficacy of this guideline compared to resuscitation with a standard isotonic solution. Methods A Phase II randomised controlled, safety and efficacy trial in Kenyan children aged over 6 months with severe malnutrition and shock including children with severe dehydration/shock and presumptive septic shock (non-diarrhoeal shock. Eligible children were randomised to HSD/5D or Ringer's Lactate (RL. A maximum of two boluses of 15 ml/kg of HSD/5D were given over two hours (as recommended by guidelines while those randomised to RL received 10 ml/kg aliquots half hourly (maximum 40 ml/kg. Primary endpoint was resolution of shock at 8 and 24 hours. Secondary outcomes included resolution of acidosis, adverse events and mortality. Results 61 children were enrolled: 41 had shock and severe dehydrating diarrhoea, 20 had presumptive septic shock; 69% had decompensated shock. By 8 hours response to volume resuscitation was poor with shock persisting in most children:-HSD/5D 15/22 (68% and RL14/25 (52%, p = 0.39. Oliguria was more prevalent at 8 hours in the HSD/5D group, 9/22 (41%, compared to RL-3/25 (12%, p = 0.02. Mortality was high, HSD/5D-15/26(58% and RL 13/29(45%; p = 0.42. Most deaths occurred within 48 hours of admission. Neither pulmonary oedema nor cardiogenic failure was detected. Conclusions Outcome was universally poor characterised by persistence of shock, oliguria and high case fatality. Isotonic fluid was associated with modest improvement in shock and survival when compared to HSD/5D but inconclusive due to the limitations of design and effectiveness of either resuscitation strategy. Although isotonic fluid resuscitation did not result in cardiogenic heart

  2. Semiparametric maximum likelihood estimation in normal transformation models for bivariate survival data

    OpenAIRE

    Yi Li; Ross L. Prentice; Xihong Lin

    2008-01-01

    We consider a class of semiparametric normal transformation models for right-censored bivariate failure times. Nonparametric hazard rate models are transformed to a standard normal model and a joint normal distribution is assumed for the bivariate vector of transformed variates. A semiparametric maximum likelihood estimation procedure is developed for estimating the marginal survival distribution and the pairwise correlation parameters. This produces an efficient estimator of the correlation ...

  3. Estimating the correlation of bivariate failure times under censoring.

    Science.gov (United States)

    Schemper, Michael; Kaider, Alexandra; Wakounig, Samo; Heinze, Georg

    2013-11-30

    The analysis of correlations within pairs of survival times is of interest to many research topics in medicine, such as the correlation of survival-type endpoints of twins, the correlation of times till failure in paired organs, or the correlation of survival time with a surrogate endpoint. The dependence of such times is assumed monotonic and thus quantification by rank correlation coefficients appropriate. The typical censoring of such times requires more involved methods of estimation and inference as have been developed in recent years. The paper focuses on semiparametric approaches, and in particular on the normal copula-based estimation of Spearman correlation coefficients. The copula approach, often presented for a mathematically inclined readership, is reviewed from the viewpoint of an applied statistician. As an alternative to the maximum likelihood methodology for the normal copula approach (NCE) we introduce an iterative multiple imputation (IMI) method which requires only about 0.05% of the computing time of NCE, without sacrificing statistical performance. For IMI, survival probabilities at death or censoring times are first transformed to normal deviates. Then, those deviates that relate to censored times are iteratively augmented, by using conditional multiple imputation, until convergence is obtained for the normal scores rank correlation, which is similar to Spearman's rank correlation. Statistical properties of NCE and IMI are compared by means of a Monte Carlo study and by means of three real data sets, which also give an impression of the typical range of applications, and of their problems. Copyright © 2013 John Wiley & Sons, Ltd.

  4. Collective estimation of multiple bivariate density functions with application to angular-sampling-based protein loop modeling

    KAUST Repository

    Maadooliat, Mehdi

    2015-10-21

    This paper develops a method for simultaneous estimation of density functions for a collection of populations of protein backbone angle pairs using a data-driven, shared basis that is constructed by bivariate spline functions defined on a triangulation of the bivariate domain. The circular nature of angular data is taken into account by imposing appropriate smoothness constraints across boundaries of the triangles. Maximum penalized likelihood is used to fit the model and an alternating blockwise Newton-type algorithm is developed for computation. A simulation study shows that the collective estimation approach is statistically more efficient than estimating the densities individually. The proposed method was used to estimate neighbor-dependent distributions of protein backbone dihedral angles (i.e., Ramachandran distributions). The estimated distributions were applied to protein loop modeling, one of the most challenging open problems in protein structure prediction, by feeding them into an angular-sampling-based loop structure prediction framework. Our estimated distributions compared favorably to the Ramachandran distributions estimated by fitting a hierarchical Dirichlet process model; and in particular, our distributions showed significant improvements on the hard cases where existing methods do not work well.

  5. A Hybrid ANN-GA Model to Prediction of Bivariate Binary Responses: Application to Joint Prediction of Occurrence of Heart Block and Death in Patients with Myocardial Infarction.

    Science.gov (United States)

    Mirian, Negin-Sadat; Sedehi, Morteza; Kheiri, Soleiman; Ahmadi, Ali

    2016-01-01

    In medical studies, when the joint prediction about occurrence of two events should be anticipated, a statistical bivariate model is used. Due to the limitations of usual statistical models, other methods such as Artificial Neural Network (ANN) and hybrid models could be used. In this paper, we propose a hybrid Artificial Neural Network-Genetic Algorithm (ANN-GA) model to prediction the occurrence of heart block and death in myocardial infarction (MI) patients simultaneously. For fitting and comparing the models, 263 new patients with definite diagnosis of MI hospitalized in Cardiology Ward of Hajar Hospital, Shahrekord, Iran, from March, 2014 to March, 2016 were enrolled. Occurrence of heart block and death were employed as bivariate binary outcomes. Bivariate Logistic Regression (BLR), ANN and hybrid ANN-GA models were fitted to data. Prediction accuracy was used to compare the models. The codes were written in Matlab 2013a and Zelig package in R3.2.2. The prediction accuracy of BLR, ANN and hybrid ANN-GA models was obtained 77.7%, 83.69% and 93.85% for the training and 78.48%, 84.81% and 96.2% for the test data, respectively. In both training and test data set, hybrid ANN-GA model had better accuracy. ANN model could be a suitable alternative for modeling and predicting bivariate binary responses when the presuppositions of statistical models are not met in actual data. In addition, using optimization methods, such as hybrid ANN-GA model, could improve precision of ANN model.

  6. Evaluation of the Erosive Potential of Selected Isotonic Drinks: In Vitro Studies.

    Science.gov (United States)

    Ostrowska, Aneta; Szymański, Witold; Kołodziejczyk, Łukasz; Bołtacz-Rzepkowska, Elżbieta

    2016-01-01

    Isotonic drinks are an important component of the diet of athletes. Sports drinks cause the body to maintain proper hydration and supplement minerals which are lost in sweat during excessive exercising. Aside from the benefits of isotonic drinks, it is important to be aware of the harmful effects of citric acid within the products, which could cause enamel erosion. The aim of the study was to evaluate the erosive potential of sports drinks using confocal scanning laser microscopy (CLSM). The studies measured the change of surface roughness of the dental enamel after etching using Isostar, Powerade and Gatorade drinks, and Fortuna orange juice. Measurements were repeated after 1, 2 and 3 h of exposure to the selected liquid. The evaluation of calcium compound contents was carried out using the complexonometric method. The surface roughness measurements of dental enamel showed that the lowest values of the parameters Ra and Rz were obtained for Isostar and orange juice. The research of the calcium content in the selected beverages showed the highest value in Isostar (320.0 mg/L) and the lowest in Powerade (40.0 mg/L) and Gatorade (21.0 mg/L). Our study confirms that Isostar is the safest sports drink, among the analyzed beverages, for athletes, because it causes the least erosive changes in dental enamel. It is recommended to supplement beverages to reduce their potential for erosion using calcium compounds.

  7. Quality and microbial safety evaluation of new isotonic beverages upon thermal treatments.

    Science.gov (United States)

    Gironés-Vilaplana, Amadeo; Huertas, Juan-Pablo; Moreno, Diego A; Periago, Paula M; García-Viguera, Cristina

    2016-03-01

    In the present study, it was evaluated how two different thermal treatments (Mild and Severe) may affect the anthocyanin content, antioxidant capacity (ABTS(+), DPPH, and FRAP), quality (CIELAB colour parameters), and microbiological safety of a new isotonic drink made of lemon and maqui berry over a commercial storage simulation using a shelf life of 56days at two preservation temperature (7°C and 37°C). Both heat treatments did not affect drastically the anthocyanins content and their percentage of retention. The antioxidant capacity, probably because of the short time, was also not affected. The CIELAB colour parameters were affected by the heat, although the isotonic drinks remained with attractive red colour during shelf life. From a microbiological point of view, the Mild heat treatment with storage at 7°C is the ideal for the preservation of microbial growth, being useful for keeping the quality and safety of beverages in commercial life. Copyright © 2015. Published by Elsevier Ltd.

  8. [Wernicke's encephalopathy due to excessive intake of isotonic drink; report of 2 cases].

    Science.gov (United States)

    Hiraki, Akiyoshi; Kikuchi, Masahiro

    2014-01-01

    Wernicke's encephalopathy (WE) is an acute neurological disease resulting from thiamine (vitamin B1) deficiency. WE is often caused by an unbalanced diet or excessively strict diet therapy in pediatric cases. We experienced 2 cases of WE due to excessive intake of isotonic drink. Patient 1 was a 15-month-old boy. After frequent vomiting, he presented with mental status changes, ocular abnormalities, and truncal ataxia (the classic triad). Patient 2 was a 7-month-old boy. He was hospitalized because of status epilepticus. In both cases, the clinical symptoms improved immediately after the administration of vitamin B1. However, mental retardation was observed as a neurological sequel in patient 2. Because many patients with WE present with vomiting at an early stage, we should take care not to confuse WE with gastroenterocolitis. In addition, it should be noted that some patients with WE present with seizure. Because these 2 cases resulted from an unbalanced diet, it is important to evaluate the patients' eating and drinking habits and advise their parents on proper nutrition. Since many people believe that isotonic drinks are very beneficial and consume them frequently, we should promote awareness that they can be harmful when consumed in excess.

  9. [Hypotonic Versus Isotonic Electrolyte Solution for Perioperative Fluid Therapy in Infants].

    Science.gov (United States)

    Bito, Kiyoko; Higuchi, Satoshi; Omura, Azusa; Kaneda, Yuri; Otaki, Reiko; Azuma, Satomi; Kojima, Mikiko; Otsuka, Naoki; Shida, Kenji; Yasumoto, Kazumasa

    2015-03-01

    This study was designed to evaluate the effects of perioperative administration of an isotonic electrolyte solution with 1% glucose (IT) on blood sodium (Na+) and blood glucose (BG) concentrations in pediatric patients hypotonic electrolyte solution with 2.6% glucose (HT). Fifty Patients were randomly allocated to HT group and IT group. Na+ and BG were measured at induction of anesthesia (Tind), the end of surgery (Tend), and 4 hours after surgery (T4h). Patient characteristics were similar for the 2 groups. In the HT group, Na+ at Tend insignificantly dropped compared with that at Tind, whereas in the IT group Na+ was significantly elevated. Na+ at T4h significantly increased compared with that at Tend in each group. No cases developed new dysnatremia or dysglycemia in IT group. The incidence of hyponatremia at Tend was significantly lower in the IT group. A positive correlation between intraoperative Na+ concentration changes and the infusion duration was observed in the IT group. Isotonic solution with 1% glucose is suggested to be safe in infants during and after surgery.

  10. Modeling force-velocity relation in skeletal muscle isotonic contraction using an artificial neural network.

    Science.gov (United States)

    Dariani, Sharareh; Keshavarz, Mansoor; Parviz, Mohsen; Raoufy, Mohammad Reza; Gharibzadeh, Shahriar

    2007-01-01

    The aim of this study is to design an artificial neural network (ANN) to model force-velocity relation in skeletal muscle isotonic contraction. We obtained the data set, including physiological and morphometric parameters, by myography and morphometric measurements on frog gastrocnemius muscle. Then, we designed a multilayer perceptron ANN, the inputs of which are muscle volume, muscle optimum length, tendon length, preload, and afterload. The output of the ANN is contraction velocity. The experimental data were divided randomly into two parts. The first part was used to train the ANN. In order to validate the model, the second part of experimental data, which was not used in training, was employed to the ANN and then, its output was compared with Hill model and the experimental data. The behavior of ANN in high forces was more similar to experimental data, but in low forces the Hill model had better results. Furthermore, extrapolation of ANN performance showed that our model is more or less able to simulate eccentric contraction. Our results indicate that ANNs represent a powerful tool to capture some essential features of muscle isotonic contraction.

  11. The effects of hypotonic and isotonic negative contrast agent on gastrointestinal distention and physiological intake of 18F-FDG.

    Science.gov (United States)

    Zhang, Lin; Liang, Ming-long; Zhang, Yong-ke; Hu, San-san; Chen, Lin; Li, Hai-tao; Wang, Jian

    2015-02-01

    The objective of this study was to explore the effects of hypotonic and isotonic oral mannitol on intestinal distention and fluorine-18 fluorodeoxyglucose ((18)F-FDG) intake in PET/computed tomography (CT) imaging. A total of 124 patients without gastrointestinal disease were evaluated with PET/CT imaging and divided into four groups using a random number table. Group 1 drank plain water, group 2 drank 2.5% mannitol, group 3 drank 2.5% mannitol and also received 10 mg of scopolamine butylbromide, and group 4 drank 2.5% mannitol and also received 20 mg of scopolamine butylbromide. The patients in each group underwent PET/CT imaging 50 min after (18)F-FDG injection. In these groups, differences such as age, sex, disease distribution, oral liquid amount, and adverse reactions were compared. Gastrointestinal distention and F-FDG intake were analyzed by two experts in nuclear medicine by visual observation. Data were statistically analyzed using a rank-sum test, R×C contingency table, one-way analysis of variance, and a paired t-test. There were no significant differences in blood glucose levels after oral administration of 2.5% mannitol (t=0.62, P>0.05). Gastrointestinal distention of patients in groups 2, 3, and 4 was superior to that of patients in group 1 (Phypotonic bowel preparation decreased the physiological intake of (18)F-FDG, increased the distention of the gastrointestinal tract, and thus improved the image quality.

  12. Computational statistics handbook with Matlab

    CERN Document Server

    Martinez, Wendy L

    2007-01-01

    Prefaces Introduction What Is Computational Statistics? An Overview of the Book Probability Concepts Introduction Probability Conditional Probability and Independence Expectation Common Distributions Sampling Concepts Introduction Sampling Terminology and Concepts Sampling Distributions Parameter Estimation Empirical Distribution Function Generating Random Variables Introduction General Techniques for Generating Random Variables Generating Continuous Random Variables Generating Discrete Random Variables Exploratory Data Analysis Introduction Exploring Univariate Data Exploring Bivariate and Trivariate Data Exploring Multidimensional Data Finding Structure Introduction Projecting Data Principal Component Analysis Projection Pursuit EDA Independent Component Analysis Grand Tour Nonlinear Dimensionality Reduction Monte Carlo Methods for Inferential Statistics Introduction Classical Inferential Statistics Monte Carlo Methods for Inferential Statist...

  13. A Comparative Study on DDF Curve with Bivariate and Univariate Model

    Science.gov (United States)

    Joo, K.; Choi, S.; Heo, J.

    2012-12-01

    DDF(or IDF) curve is consisted with rainfall depth(or intensity), duration and frequency, and it is useful to see how rainfall changes in various conditions. Furthermore, recently, multivariate frequency analysis is applied to hydrology because of its scalability. In this study, to obtain DDF curve, rainfall quantile is estimated by both of univariate and bivariate(rainfall depth and duration) frequency analysis. For bivariate model, three copula models which are Frank, Gumbel-Hougaard, and Joe, are used in this study. Copula model has been studied widely for various fields, and it is flexible for marginal distribution than other conventional bivariate models. Hourly recorded data(1961~2010) of Seoul weather station from Korea Meteorological Administration (KMA) is applied for frequency analysis, and inter-event time definition is used for identification of rainfall events. For estimate parameters of copula models, maximum pseudo-likelihood estimation method which is semi-parametric method is used. Gumbel distribution is examined and used for rainfall depth, and generalized extreme value (GEV) distribution is examined and used for duration. As a result, 4 DDF curves are obtained (univariate, 3 copula models). In compared to univariate model, rainfall quantile of bivariate model unaffected by duration. In detail, Frank model shows closest trend along the duration, and Joe model doesn`t show the little changes along the duration. Change of rainfall quantile from bivariate model along the duration is less significant than univariate model as varying nonexceedance probability.

  14. SEMG analysis of astronaut upper arm during isotonic muscle actions with normal standing posture

    Science.gov (United States)

    Qianxiang, Zhou; Chao, Ma; Xiaohui, Zheng

    sEMG analysis of astronaut upper arm during isotonic muscle actions with normal standing posture*1 Introduction Now the research on the isotonic muscle actions by using Surface Electromyography (sEMG) is becoming a pop topic in fields of astronaut life support training and rehabilitations. And researchers paid more attention on the sEMG signal processes for reducing the influence of noise which is produced during monitoring process and the fatigue estimation of isotonic muscle actions with different force levels by using the parameters which are obtained from sEMG signals such as Condition Velocity(CV), Median Frequency(MDF), Mean Frequency(MNF) and so on. As the lucubrated research is done, more and more research on muscle fatigue issue of isotonic muscle actions are carried out with sEMG analysis and subjective estimate system of Borg scales at the same time. In this paper, the relationship between the variable for fatigue based on sEMG and the Borg scale during the course of isotonic muscle actions of the upper arm with different contraction levels are going to be investigated. Methods 13 young male subjects(23.4±2.45years, 64.7±5.43Kg, 171.7±5.41cm) with normal standing postures were introduced to do isotonic actions of the upper arm with different force levels(10% MVC, 30%MVC and 50%MVC). And the MVC which means maximal voluntary contraction was obtained firstly in the experiment. Also the sEMG would be recorded during the experiments; the Borg scales would be recorded for each contraction level. By using one-third band octave method, the fatigue variable (p) based on sEMG were set up and it was expressed as p = i g(fi ) · F (fi ). And g(fi ) is defined as the frequent factor which was 0.42+0.5 cos(π fi /f0 )+0.08 cos(2π fi /f0 ), 0 f0 . According to the equations, the p could be computed and the relationship between variable p and the Borg scale would be investigated. Results In the research, three kinds of fitted curves between variable p and Borg

  15. Do isometric and isotonic exercise programs reduce pain in athletes with patellar tendinopathy in-season? : A randomised clinical trial

    NARCIS (Netherlands)

    van Ark, Mathijs; Cook, Jill L; Docking, Sean I; Zwerver, Hans; Gaida, James E; van den Akker-Scheek, Inge; Rio, Ebonie

    Objectives: Many athletes with patellar tendinopathy participate in sports with symptoms during or after activities. Current treatments do not decrease pain in-season; eccentric exercises in-season result in an increase in pain. This study examined if isometric and isotonic exercises relieved pain

  16. Level structure of 141Ba and 139Xe and the level systematics of N=85 even-odd isotones

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y.X.; Rasmussen, J.O.; Hamilton, J.H.; Ramayya, A.V.; Hwang, J.K.; Beyer, C.J.; Zhu, S.J.; Kormicki, J.; Zhang, X.Q.; Jones, E.F.; Gore, P.M.; Ginter, T.N.; Gregorich, K.E.; Lee, I-Yang; Macchiavelli, A.O.; Zielinski, P.; Folden III, C.M.; Fallon, P.; Ter-Akopian, G.M.; Oganessian, Yu.Ts.; Daniel, A.V.; Stoyer, M.A.; Cole, J.D.; Donangelo, R.; Wu, S.C.; Asztalos, S.J.

    2002-01-31

    New level schemes of {sup 141}Ba and {sup 139}Xe are proposed from the analyses of spontaneous-fission gamma data from our {sup 252}Cf spontaneous fission Gammasphere runs of 1995 and 2000. By analogy with the N = 85 even-odd isotones {sup 149}Gd, {sup 147}Sm, and {sup 145}Nd, spins and parities were assigned to the observed excited states in {sup 141}Ba and {sup 139}Xe. It appears that spherical shell model neutron excitations plus octupolephonons are an appropriate basis at the lower end of the bands. Going to higher spins it is clear that the soft rotor involving valence protons as well as neutrons becomes increasingly important in the configurations. Level systematics in the N = 85 even-odd isotones from Gd(Z=64) through Te(Z=52), are discussed. The excitation systematics and smooth trends of the analogous levels support the spin and parity assignment for excited levels observed in {sup 141}Ba and {sup 139}Xe. The level systematics and the comparison with neighboring even-even isotopes indicate that quadrupole and octupole collectivity play roles in {sup 141}Ba and {sup 139}$Xe. From Gd(Z=64) through Te(Z=52), increasing excitation energies of the 13/2{sup +} states and lowering relative intensities of the positive parity bands in the N = 85 even-odd isotones may indicate that the octupole strength is becoming weaker for the isotones when approaching the Z = 50 closed shell.

  17. Electromyographic analysis of upper limb muscles during standardized isotonic and isokinetic robotic exercise of spastic elbow in patients with stroke.

    Science.gov (United States)

    Sin, Minki; Kim, Won-Seok; Park, Daegeun; Min, Yu-Sun; Kim, Woo Jin; Cho, Kyujin; Paik, Nam-Jong

    2014-02-01

    Although it has been reported that strengthening exercise in stroke patients is beneficial for their motor recovery, there is little evidence about which exercise method is the better option. The purpose of this study was to compare isotonic and isokinetic exercise by surface electromyography (EMG) analysis using standardized methods. Nine stroke patients performed three sets of isotonic elbow extensions at 30% of their maximal voluntary isometric torque followed by three sets of maximal isokinetic elbow extensions with standardization of mean angular velocity and the total amount of work for each matched set in two strengthening modes. All exercises were done by using 1-DoF planner robot to regulate exact resistive torque and speed. Surface electromyographic activity of eight muscles in the hemiplegic shoulder and elbow was recorded. Normalized root mean square (RMS) values and co-contraction index (CCI) were used for the analysis. The isokinetic mode was shown to activate the agonists of elbow extension more efficiently than the isotonic mode (normalized RMS for pooled triceps: 96.0±17.0 (2nd), 87.8±14.4 (3rd) in isokinetic, 80.9±11.0 (2nd), 81.6±12.4 (3rd) in isotonic contraction, F[1,8]=11.168; P=0.010) without increasing the co-contraction of muscle pairs, implicating spasticity or synergy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Muscle activity during knee-extension strengthening exercise performed with elastic tubing and isotonic resistance

    DEFF Research Database (Denmark)

    Jakobsen, Markus Due; Sundstrup, Emil; Andersen, Christoffer H

    2012-01-01

    muscle during 10-RM knee-extensions performed with elastic tubing and an isotonic strength training machine. METHODS: 7 women and 9 men aged 28-67 years (mean age 44 and 41 years, respectively) participated. Electromyographic (EMG) activity was recorded in 10 muscles during the concentric and eccentric......BACKGROUND/PURPOSE: While elastic resistance training, targeting the upper body is effective for strength training, the effect of elastic resistance training on lower body muscle activity remains questionable. The purpose of this study was to evaluate the EMG-angle relationship of the quadriceps...... contraction phase of a knee extension exercise performed with elastic tubing and in training machine and normalized to maximal voluntary isometric contraction (MVC) EMG (nEMG). Knee joint angle was measured during the exercises using electronic inclinometers (range of motion 0-90°). RESULTS: When comparing...

  19. Formation of metastabil liquid phases in the isotonic solution of sodium cloraide during cooling

    Directory of Open Access Journals (Sweden)

    A. T. Ходько

    2016-07-01

    Full Text Available In this paper the cooling process cryomicroscopy of 0.15 M of isotonic sodium chloride solution was conducted. It was shown that there is liquid – liquid phase change before the crystallization process. As a result, the coarse system (highly concentrated emulsion was formed. The dispersed phase and the disperse medium in a binary system with the same qualitative chemical composition differ in concentration. Therefore, the greater is the volume ratio of the coexisting phases, the greater is the difference in their quantitative compositions. The dispersed phase, that composes the main volume in the system under investigation, should have lower NaCl concentration than the disperse medium and the initial solution. In this case it will be hypotonic (and disperse medium – hypertonic in relation to cytoplasm of human internal environment. This physical-chemical factor, which hasn’t been considered previously, might be responsible for osmotic damage in living cells during cryopreservation of cell suspensions.

  20. Causal networks clarify productivity-richness interrelations, bivariate plots do not

    Science.gov (United States)

    Grace, James B.; Adler, Peter B.; Harpole, W. Stanley; Borer, Elizabeth T.; Seabloom, Eric W.

    2014-01-01

    Perhaps no other pair of variables in ecology has generated as much discussion as species richness and ecosystem productivity, as illustrated by the reactions by Pierce (2013) and others to Adler et al.'s (2011) report that empirical patterns are weak and inconsistent. Adler et al. (2011) argued we need to move beyond a focus on simplistic bivariate relationships and test mechanistic, multivariate causal hypotheses. We feel the continuing debate over productivity–richness relationships (PRRs) provides a focused context for illustrating the fundamental difficulties of using bivariate relationships to gain scientific understanding.

  1. A note on finding peakedness in bivariate normal distribution using Mathematica

    Directory of Open Access Journals (Sweden)

    Anwer Khurshid

    2007-07-01

    Full Text Available Peakedness measures the concentration around the central value. A classical standard measure of peakedness is kurtosis which is the degree of peakedness of a probability distribution. In view of inconsistency of kurtosis in measuring of the peakedness of a distribution, Horn (1983 proposed a measure of peakedness for symmetrically unimodal distributions. The objective of this paper is two-fold. First, Horn’s method has been extended for bivariate normal distribution. Secondly, to show that computer algebra system Mathematica can be extremely useful tool for all sorts of computation related to bivariate normal distribution. Mathematica programs are also provided.

  2. [Systemic and renal effects of preventing contrast nephrotoxicity with isotonic (0.9%) and hypotonic (0.45%) saline].

    Science.gov (United States)

    Marrón, Belén; Ruiz, Elisa; Fernández, Cristina; Almeida, Pedro; Horcajada, Cristina; Navarro, Felipe; Caramelo, Carlos

    2007-10-01

    Physiological and hypotonic saline solutions have been used interchangeably for preventing contrast media nephrotoxicity. No analysis of the possible differential effects of the two solutions on the milieu interieur or intercompartmental fluid volumes has been performed. Our aim was to study the systemic and renal effects of two types of saline solution regularly used to prevent contrast media nephrotoxicity in patients undergoing coronary angiography. Changes in electrolyte levels and volume distribution were studied in 71 individuals who were randomized to receive either 0.9% isotonic saline (n=36) or 0.45% hypotonic saline (n=35) during the 12 hours before and after contrast injection (2000 mL in each period). The creatinine level was elevated equally often in the isotonic and hypotonic saline groups. Isotonic saline administration led to reductions in hemoglobin level, hematocrit and plasma albumin level, and to increases in plasma volume, by 12.3% and 10.4% at 24 and 48 hours, respectively. These changes were significant compared with baseline measurements and compared with the group that received hypotonic saline. Neither of the two saline solutions resulted in a change in plasma atrial natriuretic peptide level. Plasma and urine osmolality decreased only with hypotonic saline. The increase in plasma creatinine level was similar with both isotonic and hypotonic saline. During standard therapy for preventing contrast media nephrotoxicity, (1) isotonic saline, but not hypotonic saline, increased plasma volume; (2) this increase did not raise the atrial natriuretic peptide level; and (3) no difference in the increase in serum creatinine level was observed between the two saline solutions. These findings provide evidence that 0.45% saline, at a dose suitable for preventing contrast media nephrotoxicity, is associated with a lower risk of volume expansion. This result is important for patients with severely impaired ventricular function.

  3. Safety and efficacy of isotonic (0.9%) vs. hypotonic (0.18%) saline as maintenance intravenous fluids in children: a randomized controlled trial.

    Science.gov (United States)

    Shamim, Ahmar; Afzal, Kamran; Ali, S Manazir

    2014-12-01

    To compare the safety and efficacy of isotonic versus hypotonic maintenance fluid in children. Randomized controlled trial. Tertiary-level teaching hospital. 60 children (age 0.5 to 12 years) who were admitted and anticipated to receive intravenous fluid for the next 48 hours. Hypotonic fluid (Standard maintenance volume as 0.18% NaCl in 5% dextrose) or Isotonic fluid (60% Standard maintenance volume as 0.9% NaCl solution in 5% dextrose). Primary: Incidence of hyponatremia. Secondary: Serum sodium, serum osmolality, blood sugar, blood urea, serum creatinine, serum potassium, serum chloride, pH, urine output, change in weight, morbidity and death. At 24 hours, hyponatremia was noted in 7 (24%) patients in the isotonic and 16 (55%) in hypotonic group (P=0.031). At 48 hours, hyponatremia was noted in 4 (14%) and 13 (45%) patients in isotonic and hypotonic group, respectively (P=0.02). There was significant change in sodium levels in both isotonic (P=0.036) and hypotonic (Phypotonic group. In isotonic group, there was significant increase between 24 and 48 hours (4.3, 95% CI: 0.1, 8.4 mEq/L; P=0.04). Reduced volume isotonic fluid results in fewer episodes of hyponatremia than hypotonic fluid in sick children during the first 48 hours of intravenous fluid therapy.

  4. Accuracy of body mass index in predicting pre-eclampsia: bivariate meta-analysis

    NARCIS (Netherlands)

    Cnossen, J. S.; Leeflang, M. M. G.; de Haan, E. E. M.; Mol, B. W. J.; van der Post, J. A. M.; Khan, K. S.; ter Riet, G.

    2007-01-01

    OBJECTIVE: The objective of this study was to determine the accuracy of body mass index (BMI) (pre-pregnancy or at booking) in predicting pre-eclampsia and to explore its potential for clinical application. DESIGN: Systematic review and bivariate meta-analysis. SETTING: Medline, Embase, Cochrane

  5. Bivariate categorical data analysis using normal linear conditional multinomial probability model.

    Science.gov (United States)

    Sun, Bingrui; Sutradhar, Brajendra

    2015-02-10

    Bivariate multinomial data such as the left and right eyes retinopathy status data are analyzed either by using a joint bivariate probability model or by exploiting certain odds ratio-based association models. However, the joint bivariate probability model yields marginal probabilities, which are complicated functions of marginal and association parameters for both variables, and the odds ratio-based association model treats the odds ratios involved in the joint probabilities as 'working' parameters, which are consequently estimated through certain arbitrary 'working' regression models. Also, this later odds ratio-based model does not provide any easy interpretations of the correlations between two categorical variables. On the basis of pre-specified marginal probabilities, in this paper, we develop a bivariate normal type linear conditional multinomial probability model to understand the correlations between two categorical variables. The parameters involved in the model are consistently estimated using the optimal likelihood and generalized quasi-likelihood approaches. The proposed model and the inferences are illustrated through an intensive simulation study as well as an analysis of the well-known Wisconsin Diabetic Retinopathy status data. Copyright © 2014 John Wiley & Sons, Ltd.

  6. Sub-super-stabilizability of certain bivariate means via mean-convexity

    Directory of Open Access Journals (Sweden)

    Mustapha Raïssouli

    2016-11-01

    Full Text Available Abstract In this paper, we first show that the first Seiffert mean P is concave whereas the second Seiffert mean T and the Neuman-Sándor mean NS are convex. As applications, we establish the sub-stabilizability/super-stabilizability of certain bivariate means. Open problems are derived as well.

  7. On the matched pairs sign test using bivariate ranked set sampling ...

    African Journals Online (AJOL)

    Our numerical and theoretical results indicate that using BVRSS for the matched pairs sign test is substantially more efficient than using BVSRS. Illustration using palm trees data from sultanate of Oman is provided. Key words: Bootstrap method, bivariate ranked set sample, power of the test, P-value of the test, Pitman's ...

  8. On the construction of bivariate exponential distributions with an arbitrary correlation coefficient

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis

    In this paper we use a concept of multivariate phase-type distributions to define a class of bivariate exponential distributions. This class has the following three appealing properties. Firstly, we may construct a pair of exponentially distributed random variables with any feasible correlation...

  9. On the Construction of Bivariate Exponential Distributions with an Arbitrary Correlation Coefficient

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis

    2010-01-01

    In this article we use the concept of multivariate phase-type distributions to define a class of bivariate exponential distributions. This class has the following three appealing properties. Firstly, we may construct a pair of exponentially distributed random variables with any feasible correlation...

  10. Technical note: Towards a continuous classification of climate using bivariate colour mapping

    NARCIS (Netherlands)

    Teuling, A.J.

    2011-01-01

    Climate is often defined in terms of discrete classes. Here I use bivariate colour mapping to show that the global distribution of K¨oppen-Geiger climate classes can largely be reproduced by combining the simple means of two key states of the climate system 5 (i.e., air temperature and relative

  11. Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews

    NARCIS (Netherlands)

    Reitsma, Johannes B.; Glas, Afina S.; Rutjes, Anne W. S.; Scholten, Rob J. P. M.; Bossuyt, Patrick M.; Zwinderman, Aeilko H.

    2005-01-01

    Background and Objectives: Studies of diagnostic accuracy most often report pairs of sensitivity and specificity. We demonstrate the advantage of using bivariate meta-regression models to analyze such data. Methods: We discuss the methodology of both the summary Receiver Operating Characteristic

  12. A model for gust amplitude and gust length based on the bivariate gamma probability distribution function

    Science.gov (United States)

    Smith, O. E.; Adelfang, S. I.

    1981-01-01

    A model of the largest gust amplitude and gust length is presented which uses the properties of the bivariate gamma distribution. The gust amplitude and length are strongly dependent on the filter function; the amplitude increases with altitude and is larger in winter than in summer.

  13. A simple approximation to the bivariate normal distribution with large correlation coefficient

    NARCIS (Netherlands)

    Albers, Willem/Wim; Kallenberg, W.C.M.

    1994-01-01

    The bivariate normal distribution function is approximated with emphasis on situations where the correlation coefficient is large. The high accuracy of the approximation is illustrated by numerical examples. Moreover, exact upper and lower bounds are presented as well as asymptotic results on the

  14. Semi-automated detection of aberrant chromosomes in bivariate flow karyotypes

    NARCIS (Netherlands)

    Boschman, G. A.; Manders, E. M.; Rens, W.; Slater, R.; Aten, J. A.

    1992-01-01

    A method is described that is designed to compare, in a standardized procedure, bivariate flow karyotypes of Hoechst 33258 (HO)/Chromomycin A3 (CA) stained human chromosomes from cells with aberrations with a reference flow karyotype of normal chromosomes. In addition to uniform normalization of

  15. Meta-analysis of studies with bivariate binary outcomes: a marginal beta-binomial model approach

    Science.gov (United States)

    Chen, Yong; Hong, Chuan; Ning, Yang; Su, Xiao

    2018-01-01

    When conducting a meta-analysis of studies with bivariate binary outcomes, challenges arise when the within-study correlation and between-study heterogeneity should be taken into account. In this paper, we propose a marginal beta-binomial model for the meta-analysis of studies with binary outcomes. This model is based on the composite likelihood approach, and has several attractive features compared to the existing models such as bivariate generalized linear mixed model (Chu and Cole, 2006) and Sarmanov beta-binomial model (Chen et al., 2012). The advantages of the proposed marginal model include modeling the probabilities in the original scale, not requiring any transformation of probabilities or any link function, having closed-form expression of likelihood function, and no constraints on the correlation parameter. More importantly, since the marginal beta-binomial model is only based on the marginal distributions, it does not suffer from potential misspecification of the joint distribution of bivariate study-specific probabilities. Such misspecification is difficult to detect and can lead to biased inference using currents methods. We compare the performance of the marginal beta-binomial model with the bivariate generalized linear mixed model and the Sarmanov beta-binomial model by simulation studies. Interestingly, the results show that the marginal beta-binomial model performs better than the Sarmanov beta-binomial model, whether or not the true model is Sarmanov beta-binomial, and the marginal beta-binomial model is more robust than the bivariate generalized linear mixed model under model misspecifications. Two meta-analyses of diagnostic accuracy studies and a meta-analysis of case-control studies are conducted for illustration. PMID:26303591

  16. New isotonic drinks with antioxidant and biological capacities from berries (maqui, açaí and blackthorn) and lemon juice.

    Science.gov (United States)

    Gironés-Vilaplana, Amadeo; Villaño, Débora; Moreno, Diego A; García-Viguera, Cristina

    2013-11-01

    The aim of the study was to design new isotonic drinks with lemon juice and berries: maqui [Aristotelia chilensis (Molina) Stuntz], açaí (Euterpe oleracea Mart.) and blackthorn (Prunus spinosa L.), following on from previous research. Quality parameters - including colour (CIELab parameters), minerals, phytochemical identification and quantification by high-performance liquid chromatography with diode array detector, total phenolic content by the Folin-Ciocalteu reagent, the antioxidant capacity (ABTS(+), DPPH• and [Formula: see text] assays) and biological activities (in vitro alpha-glucosidase and lipase inhibitory effects) - were tested in the samples and compared to commercially available isotonic drinks. The new isotonic blends with lemon and anthocyanins-rich berries showed an attractive colour, especially in maqui samples, which is essential for consumer acceptance. Significantly higher antioxidant and biological effects were determined in the new blends, in comparison with the commercial isotonic beverages.

  17. Bivariate functional data clustering: grouping streams based on a varying coefficient model of the stream water and air temperature relationship

    Science.gov (United States)

    H. Li; X. Deng; Andy Dolloff; E. P. Smith

    2015-01-01

    A novel clustering method for bivariate functional data is proposed to group streams based on their water–air temperature relationship. A distance measure is developed for bivariate curves by using a time-varying coefficient model and a weighting scheme. This distance is also adjusted by spatial correlation of streams via the variogram. Therefore, the proposed...

  18. New K isomers in the neutron-rich N =100 isotones 162Sm, 163Eu, and 164Gd

    Science.gov (United States)

    Yokoyama, R.; Go, S.; Kameda, D.; Kubo, T.; Inabe, N.; Fukuda, N.; Takeda, H.; Suzuki, H.; Yoshida, K.; Kusaka, K.; Tanaka, K.; Yanagisawa, Y.; Ohtake, M.; Sato, H.; Shimizu, Y.; Baba, H.; Kurokawa, M.; Nishimura, D.; Ohnishi, T.; Iwasa, N.; Chiba, A.; Yamada, T.; Ideguchi, E.; Fujii, T.; Nishibata, H.; Ieki, K.; Murai, D.; Momota, S.; Sato, Y.; Hwang, J. W.; Kim, S.; Tarasov, O. B.; Morrissey, D. J.; Sherrill, B. M.; Simpson, G.; Praharaj, C. R.

    2017-03-01

    Very neutron-rich Z ˜60 isotopes produced by in-flight fission of a 345 MeV/nucleon 238U beam at the RI Beam Factory, RIKEN Nishina Center, have been studied by delayed γ -ray spectroscopy. New isomers were discovered in the neutron-rich N =100 isotones 162Sm, 163Eu, and 164Gd. Half-lives, γ -ray energies, and relative intensities of these isomers were obtained. Level schemes were proposed for these nuclei and the first 2+ and 4+ states were assigned for the even-even nuclei. The first 2+ and 4+ state energies decrease as the proton numbers get smaller. The energies and the half-lives of the new isomers are very similar to those of 4- isomers known in less neutron-rich N =100 isotones 168Er and 170Yb. A deformed Hartree-Fock with angular momentum projection model suggests Kπ=4- two-quasiparticle states with ν 7 /2 [633 ]⊗ν 1 /2 [521 ] configurations with similar excitation energy. The results suggest that neutron-rich N =100 nuclei are well deformed and the deformation gets larger as Z decreases to 62. The onset of K isomers with the same configuration at almost the same energy in N =100 isotones indicates that the neutron single-particle structures of neutron-rich isotones down to Z =62 do not change significantly from those of the Z =70 stable nuclei. Systematics of the excitation energies of new isomers can be explained without the predicted N =100 shell gap.

  19. Knee-joint proprioception during 30-day 6 degrees head-down bed rest with isotonic and isokinetic exercise training

    Science.gov (United States)

    Bernauer, E. M.; Walby, W. F.; Ertl, A. C.; Dempster, P. T.; Bond, M.; Greenleaf, J. E.

    1994-01-01

    To determine if daily isotonic exercise or isokinetic exercise training coupled with daily leg proprioceptive training, would influence leg proprioceptive tracking responses during bed rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a no-exercise (NOE) training control group (n = 5), and isotonic exercise (ITE, n = 7) and isokinetic exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min periods.d-1, 5 d.week-1. Only the IKE group performed proprioceptive training using a new isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pre-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p proprioceptive tracking was unchanged during BR with NOE, both isotonic exercise training (without additional proprioceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.

  20. Comparison of the effects of hydration with water or isotonic solution on the recovery of cardiac autonomic modulation.

    Science.gov (United States)

    Vanderlei, Franciele Marques; Moreno, Isadora Lessa; Vanderlei, Luiz Carlos; Pastre, Carlos Marcelo; de Abreu, Luiz Carlos; Ferreira, Celso

    2015-04-01

    Despite the importance of hydration during exercise, the impact of ingesting water or isotonic solution during and after exercise on the regulation of autonomic modulation is unclear. The study aimed to compare the effect of ingesting water or isotonic solution (Gatorade®, Brazil) on cardiac autonomic modulation in young people after submaximal aerobic exercise. Thirty-one young men were subjected to a protocol consisting of 4 steps: 1) incremental test, 2) control protocol without hydration, 3) protocol with ingestion of water, and 4) protocol with ingestion of isotonic solution. The protocol consisted of 10 min of rest, 90 min of treadmill exercise at 60% VO2peak, and 60 min of recovery at rest. In the hydration protocols, hydration occurred during and after exercise, every 15 min beginning after the 15th minute of exercise, with the amount ingested proportional to body mass lost in the control protocol. Autonomic modulation was evaluated by heart rate variability. The hydration protocols promoted a more efficient recovery of autonomic modulation, and for the exercise performed, regardless of the hydration administered, the effect on autonomic modulation was similar.

  1. Isotonic versus hypotonic fluid supplementation in term neonates with severe hyperbilirubinemia - a double-blind, randomized, controlled trial.

    Science.gov (United States)

    Balasubramanian, Karthik; Kumar, Praveen; Saini, Shiv Sajan; Attri, Savita Verma; Dutta, Sourabh

    2012-03-01

    To compare the incidence of hyponatremia in full-term neonates with severe hyperbilirubinemia, receiving intravenous fluid supplementation with 0.2% saline in 5% dextrose versus 0.9% saline in 5% dextrose, to prevent blood exchange transfusion (BET). In this double-blind, randomized, controlled trial, full-term newborns (≥37 weeks), appropriate for gestational age, with severe non-haemolytic hyperbilirubinemia (serum bilirubin ≥ 20 mg/dL) were enrolled. Eligible neonates were randomized to receive either 0.2% saline in 5% dextrose (hypotonic fluid group) or 0.9% saline in 5% dextrose (isotonic fluid group) over 8 hrs, in addition to phototherapy. The primary outcome was proportion of neonates developing hyponatremia (serum Na hypotonic fluid group as compared to isotonic fluid group (48.8% vs. 10.5%, p hypotonic fluid to prevent BET was associated with a higher incidence of hyponatremia while isotonic fluid was associated with an increased incidence of hypernatremia. © 2011 The Author(s)/Acta Paediatrica © 2011 Foundation Acta Paediatrica.

  2. Evaluation of sensorial, phytochemical and biological properties of new isotonic beverages enriched with lemon and berries during shelf life.

    Science.gov (United States)

    Gironés-Vilaplana, Amadeo; Mena, Pedro; Moreno, Diego A; García-Viguera, Cristina

    2014-04-01

    The aim of this work was to design new isotonic drinks with lemon juice and berries: maqui (Aristotelia chilensis (Molina) Stuntz), açaí (Euterpe oleracea Mart.) and blackthorn (Prunus spinosa L.), following previous research. Quality parameters, sensorial attributes, antioxidant activities (ABTS(+), DPPH(•) and O2(•-) assays) and biological capacities (α-glucosidase and lipase inhibitory assays) were evaluated over 70 days of shelf-life period. Maqui isotonic blends were the most active in all antioxidant assays (8.35 and 3.07 mmol L(-1) Trolox for ABTS(+) and DPPH(•)), in the lipase inhibitory assay (43.19 U L(-1)), and showed the highest total phenol content by the Folin-Ciocalteu test (80.97 mg 100 mL(-1) gallic acid), as a result of its higher content of total anthocyanins (42.42 mg 100 mL(-1)). Berry mixtures were also the most potent inhibitors of α-glucosidase between all samples, and displayed an attractive red colour and good sensorial attributes. All the studied parameters remained quite stable during preservation, in general, and the new isotonic drinks can be useful to equilibrate redox balance in acute and intense exercise, and support weight loss programmes, avoiding triglyceride absorption and hyperglycaemia involved in obesity and diabetes mellitus, respectively. Further research in vivo is necessary to verify their beneficial effects for sports, nutrition and health. © 2013 Society of Chemical Industry.

  3. A Review of Classification Techniques of EMG Signals during Isotonic and Isometric Contractions

    Directory of Open Access Journals (Sweden)

    Nurhazimah Nazmi

    2016-08-01

    Full Text Available In recent years, there has been major interest in the exposure to physical therapy during rehabilitation. Several publications have demonstrated its usefulness in clinical/medical and human machine interface (HMI applications. An automated system will guide the user to perform the training during rehabilitation independently. Advances in engineering have extended electromyography (EMG beyond the traditional diagnostic applications to also include applications in diverse areas such as movement analysis. This paper gives an overview of the numerous methods available to recognize motion patterns of EMG signals for both isotonic and isometric contractions. Various signal analysis methods are compared by illustrating their applicability in real-time settings. This paper will be of interest to researchers who would like to select the most appropriate methodology in classifying motion patterns, especially during different types of contractions. For feature extraction, the probability density function (PDF of EMG signals will be the main interest of this study. Following that, a brief explanation of the different methods for pre-processing, feature extraction and classifying EMG signals will be compared in terms of their performance. The crux of this paper is to review the most recent developments and research studies related to the issues mentioned above.

  4. A Review of Classification Techniques of EMG Signals during Isotonic and Isometric Contractions

    Science.gov (United States)

    Nazmi, Nurhazimah; Abdul Rahman, Mohd Azizi; Yamamoto, Shin-Ichiroh; Ahmad, Siti Anom; Zamzuri, Hairi; Mazlan, Saiful Amri

    2016-01-01

    In recent years, there has been major interest in the exposure to physical therapy during rehabilitation. Several publications have demonstrated its usefulness in clinical/medical and human machine interface (HMI) applications. An automated system will guide the user to perform the training during rehabilitation independently. Advances in engineering have extended electromyography (EMG) beyond the traditional diagnostic applications to also include applications in diverse areas such as movement analysis. This paper gives an overview of the numerous methods available to recognize motion patterns of EMG signals for both isotonic and isometric contractions. Various signal analysis methods are compared by illustrating their applicability in real-time settings. This paper will be of interest to researchers who would like to select the most appropriate methodology in classifying motion patterns, especially during different types of contractions. For feature extraction, the probability density function (PDF) of EMG signals will be the main interest of this study. Following that, a brief explanation of the different methods for pre-processing, feature extraction and classifying EMG signals will be compared in terms of their performance. The crux of this paper is to review the most recent developments and research studies related to the issues mentioned above. PMID:27548165

  5. Hypotonic versus isotonic maintenance fluids in critically ill children: a multicenter prospective randomized study.

    Science.gov (United States)

    Rey, Corsino; Los-Arcos, Marta; Hernández, Arturo; Sánchez, Amelia; Díaz, Juan-José; López-Herce, Jesús

    2011-08-01

    Study the influence of hypotonic (HT) and isotonic (IT) maintenance fluids in the incidence of dysnatraemias in critically ill children. Prospective, randomized study conducted in three paediatric intensive care units (PICU). One hundred and twenty-five children requiring maintenance fluid therapy were included: 62 received HT fluids (50-70 mmol/L tonicity) and 63 IT fluids (156 mmol/L tonicity). Age, weight, cause of admission, sodium and fluid intake, and diuresis were collected. Blood electrolytes were measured on admission, 12 and 24 h later. Blood sodium levels at 12 h were 133.7±2.7 mmol/L in HT group vs. 136.8±3.5 mmol/L in IT group (p=0.001). Adjusted for age, weight and sodium level at PICU admission, the blood sodium values of patients receiving HT fluids decrease by 3.22 mmol/L (CI: 4.29/2.15)(p=0.000). Adjusted for age, weight and hyponatraemia incidence at admission, patients receiving HT fluids increased the risk of hyponatraemia by 5.8-fold (CI: 2.4-14.0) during the study period (p=0.000). Hypotonic maintenance fluids increase the incidence of hyponatraemia because they decrease blood sodium levels in normonatraemic patients. IT maintenance fluids do not increase the incidence of dysnatraemias and should be considered as the standard maintenance fluids. © 2011 The Author(s)/Acta Paediatrica © 2011 Foundation Acta Paediatrica.

  6. Isotonic tube feeding formula induces liquid stool in normal subjects: reversal by pectin.

    Science.gov (United States)

    Zimmaro, D M; Rolandelli, R H; Koruda, M J; Settle, R G; Stein, T P; Rombeau, J L

    1989-01-01

    Diarrhea is one of the most common complications in patients who receive tube-feeding formulas. Since the colon is the final site of water and electrolyte absorption and ultimately determines fecal composition, diarrhea during tube feeding may result from altered colonic function. The lack of dietary fiber, such as pectin, in tube-feeding formulas may be one of the means by which colonic function is affected. The purpose of this study was to determine the effect of a standard, liquid, commercially available, isotonic tube-feeding formula (ITFF) and the effects of supplementing the ITFF with pectin on colonic function as measured by stool consistency and colonic fluid composition in 13 normal adults. Data were obtained when subjects consumed their regular diet, ITFF, and ITFF supplemented with pectin using the technique of in vivo dialysis of colonic fluid. Ingestion of the ITFF resulted in a significant increase in the percentage of liquid stools compared to a regular diet [median (interquartile range) = 0% (0), 60% (64); p less than 0.01]. Ingestion of the ITFF also resulted in significant decreases in the concentrations of sodium, potassium, and short-chain fatty acids, and increases in pH and osmotic gap in colonic fluid compared to the subjects' regular diet. Supplementing the ITFF with pectin significantly reduced the incidence of liquid stools [0% (0)] and promoted a normalization of colonic fluid composition. The results suggest that the addition of pectin may enhance tolerance to ITFFs.

  7. Smoothing of the bivariate LOD score for non-normal quantitative traits.

    Science.gov (United States)

    Buil, Alfonso; Dyer, Thomas D; Almasy, Laura; Blangero, John

    2005-12-30

    Variance component analysis provides an efficient method for performing linkage analysis for quantitative traits. However, type I error of variance components-based likelihood ratio testing may be affected when phenotypic data are non-normally distributed (especially with high values of kurtosis). This results in inflated LOD scores when the normality assumption does not hold. Even though different solutions have been proposed to deal with this problem with univariate phenotypes, little work has been done in the multivariate case. We present an empirical approach to adjust the inflated LOD scores obtained from a bivariate phenotype that violates the assumption of normality. Using the Collaborative Study on the Genetics of Alcoholism data available for the Genetic Analysis Workshop 14, we show how bivariate linkage analysis with leptokurtotic traits gives an inflated type I error. We perform a novel correction that achieves acceptable levels of type I error.

  8. Obtaining DDF Curves of Extreme Rainfall Data Using Bivariate Copula and Frequency Analysis

    DEFF Research Database (Denmark)

    Sadri, Sara; Madsen, Henrik; Mikkelsen, Peter Steen

    2009-01-01

    of individual rainfall events; and (3) by storage volume and duration. In each case we used partial duration series (PDS) to extract extreme rainfall variables. The DDF curves derived from each method are presented and compared. This study examines extreme rainfall data from catchment Vedbæ k Renseanlæ g......The traditional rainfall intensity-duration-frequency (IDF) curve is a reliable approach for representing the variation of rainfall intensity with duration for a given return period. In reality rainfall variables intensity, depth and duration are dependent and therefore a bivariate analysis using...... copulas can give a more accurate IDF curve. We study IDF curves using a copula in a bivariate frequency analysis of extreme rainfall. To be able to choose the most suitable copula among candidate copulas (i.e., Gumbel, Clayton, and Frank) we demonstrated IDF curves based on variation of depth...

  9. A spatial bivariate probit model for correlated binary data with application to adverse birth outcomes.

    Science.gov (United States)

    Neelon, Brian; Anthopolos, Rebecca; Miranda, Marie Lynn

    2014-04-01

    Motivated by a study examining geographic variation in birth outcomes, we develop a spatial bivariate probit model for the joint analysis of preterm birth and low birth weight. The model uses a hierarchical structure to incorporate individual and areal-level information, as well as spatially dependent random effects for each spatial unit. Because rates of preterm birth and low birth weight are likely to be correlated within geographic regions, we model the spatial random effects via a bivariate conditionally autoregressive prior, which induces regional dependence between the outcomes and provides spatial smoothing and sharing of information across neighboring areas. Under this general framework, one can obtain region-specific joint, conditional, and marginal inferences of interest. We adopt a Bayesian modeling approach and develop a practical Markov chain Monte Carlo computational algorithm that relies primarily on easily sampled Gibbs steps. We illustrate the model using data from the 2007-2008 North Carolina Detailed Birth Record.

  10. Global assessment of predictability of water availability: A bivariate probabilistic Budyko analysis

    Science.gov (United States)

    Wang, Weiguang; Fu, Jianyu

    2018-02-01

    Estimating continental water availability is of great importance for water resources management, in terms of maintaining ecosystem integrity and sustaining society development. To more accurately quantify the predictability of water availability, on the basis of univariate probabilistic Budyko framework, a bivariate probabilistic Budyko approach was developed using copula-based joint distribution model for considering the dependence between parameter ω of Wang-Tang's equation and the Normalized Difference Vegetation Index (NDVI), and was applied globally. The results indicate the predictive performance in global water availability is conditional on the climatic condition. In comparison with simple univariate distribution, the bivariate one produces the lower interquartile range under the same global dataset, especially in the regions with higher NDVI values, highlighting the importance of developing the joint distribution by taking into account the dependence structure of parameter ω and NDVI, which can provide more accurate probabilistic evaluation of water availability.

  11. Modeling two-vehicle crash severity by a bivariate generalized ordered probit approach.

    Science.gov (United States)

    Chiou, Yu-Chiun; Hwang, Cherng-Chwan; Chang, Chih-Chin; Fu, Chiang

    2013-03-01

    This study simultaneously models crash severity of both parties in two-vehicle accidents at signalized intersections in Taipei City, Taiwan, using a novel bivariate generalized ordered probit (BGOP) model. Estimation results show that the BGOP model performs better than the conventional bivariate ordered probit (BOP) model in terms of goodness-of-fit indices and prediction accuracy and provides a better approach to identify the factors contributing to different severity levels. According to estimated parameters in latent propensity functions and elasticity effects, several key risk factors are identified-driver type (age>65), vehicle type (motorcycle), violation type (alcohol use), intersection type (three-leg and multiple-leg), collision type (rear ended), and lighting conditions (night and night without illumination). Corresponding countermeasures for these risk factors are proposed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Reprint of "Modeling two-vehicle crash severity by a bivariate generalized ordered probit approach".

    Science.gov (United States)

    Chiou, Yu-Chiun; Hwang, Cherng-Chwan; Chang, Chih-Chin; Fu, Chiang

    2013-12-01

    This study simultaneously models crash severity of both parties in two-vehicle accidents at signalized intersections in Taipei City, Taiwan, using a novel bivariate generalized ordered probit (BGOP) model. Estimation results show that the BGOP model performs better than the conventional bivariate ordered probit (BOP) model in terms of goodness-of-fit indices and prediction accuracy and provides a better approach to identify the factors contributing to different severity levels. According to estimated parameters in latent propensity functions and elasticity effects, several key risk factors are identified-driver type (age>65), vehicle type (motorcycle), violation type (alcohol use), intersection type (three-leg and multiple-leg), collision type (rear ended), and lighting conditions (night and night without illumination). Corresponding countermeasures for these risk factors are proposed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. The bivariate probit model of uncomplicated control of tumor: a heuristic exposition of the methodology.

    Science.gov (United States)

    Herbert, D

    1997-08-01

    To describe the concept, models, and methods for the construction of estimates of joint probability of uncomplicated control of tumors in radiation oncology. Interpolations using this model can lead to the identification of more efficient treatment regimens for an individual patient. The requirement to find the treatment regimen that will maximize the joint probability of uncomplicated control of tumors suggests a new class of evolutionary experimental designs--Response Surface Methods--for clinical trials in radiation oncology. The software developed by Lesaffre and Molenberghs is used to construct bivariate probit models of the joint probability of uncomplicated control of cancer of the oropharynx from a set of 45 patients for each of whom the presence/absence of recurrent tumor (the binary event E1/E1) and the presence/absence of necrosis (the binary event E2/E2) of the normal tissues of the target volume is recorded, together with the treatment variables dose, time, and fractionation. The bivariate probit model can be used to select a treatment regime that will give a specified probability, say P(S) = 0.60, of uncomplicated control of tumor by interpolation within a set of treatment regimens with known outcomes of recurrence and necrosis. The bivariate probit model can be used to guide a sequence of clinical trials to find the maximum probability of uncomplicated control of tumor for patients in a given prognostic stratum using Response Surface Methods by extrapolation from an initial set of treatment regimens. The design of treatments for individual patients and the design of clinical trials might be improved by use of a bivariate probit model and Response Surface Methods.

  14. The approximation of bivariate Chlodowsky-Sz?sz-Kantorovich-Charlier-type operators

    OpenAIRE

    Agrawal, Purshottam Narain; Baxhaku, Behar; Chauhan, Ruchi

    2017-01-01

    Abstract In this paper, we introduce a bivariate Kantorovich variant of combination of Szász and Chlodowsky operators based on Charlier polynomials. Then, we study local approximation properties for these operators. Also, we estimate the approximation order in terms of Peetre’s K-functional and partial moduli of continuity. Furthermore, we introduce the associated GBS-case (Generalized Boolean Sum) of these operators and study the degree of approximation by means of the Lipschitz class of Bög...

  15. Bipolar and bivariate models in multi-criteria decision analysis: descriptive and constructive approaches

    OpenAIRE

    Grabisch, Michel; Greco,Salvatore; Pirlot, Marc

    2008-01-01

    International audience; Multi-criteria decision analysis studies decision problems in which the alternatives are evaluated on several dimensions or viewpoints. In the problems we consider in this paper, the scales used for assessing the alternatives with respect to a viewpoint are bipolar and univariate or unipolar and bivariate. In the former case, the scale is divided in two zones by a neutral point; a positive feeling is associated to the zone above the neutral point and a negative feeling...

  16. Self-consistent nonparametric maximum likelihood estimator of the bivariate survivor function

    OpenAIRE

    R. L. Prentice

    2014-01-01

    As usually formulated the nonparametric likelihood for the bivariate survivor function is overparameterized, resulting in uniqueness problems for the corresponding nonparametric maximum likelihood estimator. Here the estimation problem is redefined to include parameters for marginal hazard rates, and for double failure hazard rates only at informative uncensored failure time grid points where there is pertinent empirical information. Double failure hazard rates at other grid points in the ris...

  17. Bivariate return periods of temperature and precipitation explain a large fraction of European crop yields

    Science.gov (United States)

    Zscheischler, Jakob; Orth, Rene; Seneviratne, Sonia I.

    2017-07-01

    Crops are vital for human society. Crop yields vary with climate and it is important to understand how climate and crop yields are linked to ensure future food security. Temperature and precipitation are among the key driving factors of crop yield variability. Previous studies have investigated mostly linear relationships between temperature and precipitation and crop yield variability. Other research has highlighted the adverse impacts of climate extremes, such as drought and heat waves, on crop yields. Impacts are, however, often non-linearly related to multivariate climate conditions. Here we derive bivariate return periods of climate conditions as indicators for climate variability along different temperature-precipitation gradients. We show that in Europe, linear models based on bivariate return periods of specific climate conditions explain on average significantly more crop yield variability (42 %) than models relying directly on temperature and precipitation as predictors (36 %). Our results demonstrate that most often crop yields increase along a gradient from hot and dry to cold and wet conditions, with lower yields associated with hot and dry periods. The majority of crops are most sensitive to climate conditions in summer and to maximum temperatures. The use of bivariate return periods allows the integration of non-linear impacts into climate-crop yield analysis. This offers new avenues to study the link between climate and crop yield variability and suggests that they are possibly more strongly related than what is inferred from conventional linear models.

  18. Robust bivariate error detection in skewed data with application to historical radiosonde winds

    KAUST Repository

    Sun, Ying

    2017-01-18

    The global historical radiosonde archives date back to the 1920s and contain the only directly observed measurements of temperature, wind, and moisture in the upper atmosphere, but they contain many random errors. Most of the focus on cleaning these large datasets has been on temperatures, but winds are important inputs to climate models and in studies of wind climatology. The bivariate distribution of the wind vector does not have elliptical contours but is skewed and heavy-tailed, so we develop two methods for outlier detection based on the bivariate skew-t (BST) distribution, using either distance-based or contour-based approaches to flag observations as potential outliers. We develop a framework to robustly estimate the parameters of the BST and then show how the tuning parameter to get these estimates is chosen. In simulation, we compare our methods with one based on a bivariate normal distribution and a nonparametric approach based on the bagplot. We then apply all four methods to the winds observed for over 35,000 radiosonde launches at a single station and demonstrate differences in the number of observations flagged across eight pressure levels and through time. In this pilot study, the method based on the BST contours performs very well.

  19. Comparison of 0.3% Hypotonic and Isotonic Sodium Hyaluronate Eye Drops in the Treatment of Experimental Dry Eye.

    Science.gov (United States)

    Li, Ying; Cui, Lian; Lee, Hyo Seok; Kang, Yeon Soo; Choi, Won; Yoon, Kyung Chul

    2017-08-01

    To compare the efficacy of 0.3% hypotonic and isotonic sodium hyaluronate (SH) eye drops in the treatment of experimental dry eye. Experimental dry eye was established in female C57BL/6 mice by subcutaneous scopolamine injection and an air draft. The mice were divided into three groups (n = 15): control, preservative-free 0.3% isotonic SH, and preservative-free 0.3% hypotonic SH. The tear volume, tear film break-up time, and corneal fluorescein staining scores were measured 5 and 10 days after treatment. After conjunctival tissues were excised at 10 days, the levels of interleukin (IL)-6, IL-17, interferon (IFN)-γ, and IFN-γ inducible protein-10 were determined using the multiplex immunobead assay. In addition, PAS staining and flow cytometry were performed to evaluate the counts of conjunctival goblet cells and CD4+ IFN-γ+ T cells. Mice treated with 0.3% hypotonic SH showed a significant decrease in corneal staining scores (P = 0.04) and the levels of IL-6 (16.7 ± 1.4 pg/mL, P = 0.02) and IFN-γ (46.5 ± 11.5 pg/mL, P = 0.02) compared to mice treated with 0.3% isotonic SH (IL-6; 32.5 ± 8.8 pg/mL, IFN-γ; 92.0 ± 16.0 pg/mL) at day 10. Although no significant difference in CD4+ IFN-γ+ T cell numbers was observed, goblet cell counts were higher in the hyopotonic SH group than in the isotonic SH group (P = 0.02). When compared to 0.3% isotonic SH eye drops, 0.3% hypotonic SH eye drops can be more effective by improving corneal staining scores, decreasing inflammatory molecules, and increasing goblet cell counts for experimental dry eye. These data suggest that hypotonic artificial tears may be useful as an adjunctive treatment for inflammatory dry eye.

  20. Effectiveness of enforcement levels of speed limit and drink driving laws and associated factors – Exploratory empirical analysis using a bivariate ordered probit model

    Directory of Open Access Journals (Sweden)

    Behram Wali

    2017-06-01

    Full Text Available The contemporary traffic safety research comprises little information on quantifying the simultaneous association between drink driving and speeding among fatally injured drivers. Potential correlation between driver's drink driving and speeding behavior poses a substantial methodological concern which needs investigation. This study therefore focused on investigating the simultaneous impact of socioeconomic factors, fatalities, vehicle ownership, health services and highway agency road safety policies on enforcement levels of speed limit and drink driving laws. The effectiveness of enforcement levels of speed limit and drink driving laws has been investigated through development of bivariate ordered probit model using data extricated from WHO's global status report on road safety in 2013. The consistent and intuitive parameter estimates along with statistically significant correlation between response outcomes validates the statistical supremacy of bivariate ordered probit model. The results revealed that fatalities per thousand registered vehicles, hospital beds per hundred thousand population and road safety policies are associated with a likely medium or high effectiveness of enforcement levels of speed limit and drink driving laws, respectively. Also, the model encapsulates the effect of several other agency related variables and socio-economic status on the response outcomes. Marginal effects are reported for analyzing the impact of such factors on intermediate categories of response outcomes. The results of this study are expected to provide necessary insights to elemental enforcement programs. Also, marginal effects of explanatory variables may provide useful directions for formulating effective policy countermeasures for overcoming driver's speeding and drink driving behavior.

  1. Nonlinear coupling between cortical oscillations and muscle activity during isotonic wrist flexion

    Directory of Open Access Journals (Sweden)

    Yuan Yang

    2016-12-01

    Full Text Available Coupling between cortical oscillations and muscle activity facilitates neuronal communication during motor control. The linear part of this coupling, known as corticomuscular coherence, has received substantial attention, even though neuronal communication underlying motor control has been demonstrated to be highly nonlinear. A full assessment of corticomuscular coupling, including the nonlinear part, is essential to understand the neuronal communication within the sensorimotor system. In this study, we applied the recently developed n:m coherence method to assess nonlinear corticomuscular coupling during isotonic wrist flexion. The n:m coherence is a generalized metric for quantifying nonlinear cross-frequency coupling as well as linear iso-frequency coupling. By using independent component analysis and equivalent current dipole source localization, we identify four sensorimotor related brain areas based on the locations of the dipoles, i.e. the contralateral primary sensorimotor areas, supplementary motor area, prefrontal area and posterior parietal cortex. For all these areas, linear coupling between EEG and EMG is present with peaks in the beta band (15-35 Hz, while nonlinear coupling is detected with both integer (1:2, 1:3, 1:4 and non-integer (2:3 harmonics. Significant differences between brain areas is shown in linear coupling with stronger coherence for the primary sensorimotor areas and motor association cortices (supplementary motor area, prefrontal area compared to the sensory association area (posterior parietal cortex; but not for the nonlinear coupling. Moreover, the detected nonlinear coupling is similar to previously reported nonlinear coupling of cortical activity to somatosensory stimuli. We suggest that the descending motor pathways mainly contribute to linear corticomuscular coupling, while nonlinear coupling likely originates from sensory feedback.

  2. Technology-enhanced Interactive Teaching of Marginal, Joint and Conditional Probabilities: The Special Case of Bivariate Normal Distribution

    Science.gov (United States)

    Dinov, Ivo D.; Kamino, Scott; Bhakhrani, Bilal; Christou, Nicolas

    2014-01-01

    Summary Data analysis requires subtle probability reasoning to answer questions like What is the chance of event A occurring, given that event B was observed? This generic question arises in discussions of many intriguing scientific questions such as What is the probability that an adolescent weighs between 120 and 140 pounds given that they are of average height? and What is the probability of (monetary) inflation exceeding 4% and housing price index below 110? To address such problems, learning some applied, theoretical or cross-disciplinary probability concepts is necessary. Teaching such courses can be improved by utilizing modern information technology resources. Students’ understanding of multivariate distributions, conditional probabilities, correlation and causation can be significantly strengthened by employing interactive web-based science educational resources. Independent of the type of a probability course (e.g. majors, minors or service probability course, rigorous measure-theoretic, applied or statistics course) student motivation, learning experiences and knowledge retention may be enhanced by blending modern technological tools within the classical conceptual pedagogical models. We have designed, implemented and disseminated a portable open-source web-application for teaching multivariate distributions, marginal, joint and conditional probabilities using the special case of bivariate Normal distribution. A real adolescent height and weight dataset is used to demonstrate the classroom utilization of the new web-application to address problems of parameter estimation, univariate and multivariate inference. PMID:25419016

  3. Serotoninergic Modulation of Basal Cardiovascular Responses and Responses Induced by Isotonic Extracellular Volume Expansion in Rats.

    Science.gov (United States)

    Semionatto, Isadora Ferraz; Raminelli, Adrieli Oliveira; Alves, Angelica Cristina; Capitelli, Caroline Santos; Chriguer, Rosangela Soares

    2017-02-01

    Isotonic blood volume expansion (BVE) induced alterations of sympathetic and parasympathetic activity in the heart and blood vessels, which can be modulated by serotonergic pathways. To evaluate the effect of saline or serotonergic agonist (DOI) administration in the hypothalamic paraventricular nucleus (PVN) on cardiovascular responses after BVE. We recorded pulsatile blood pressure through the femoral artery to obtain the mean arterial pressure (MAP), systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR) and the sympathetic-vagal ratio (LF/HF) of Wistar rats before and after they received bilateral microinjections of saline or DOI into the PVN, followed by BVE. No significant differences were observed in the values of the studied variables in the different treatments from the control group. However, when animals are treated with DOI followed by BVE there is a significant increase in relation to the BE control group in all the studied variables: MBP (114.42±7.85 vs 101.34±9.17); SBP (147.23±14.31 vs 129.39±10.70); DBP (98.01 ±4.91 vs 87.31±8.61); HR (421.02±43.32 vs 356.35±41.99); and LF/HF ratio (2.32±0.80 vs 0.27±0.32). The present study showed that the induction of isotonic BVE did not promote alterations in MAP, HR and LF/HF ratio. On the other hand, the injection of DOI into PVN of the hypothalamus followed by isotonic BVE resulted in a significant increase of all variables. These results suggest that serotonin induced a neuromodulation in the PVN level, which promotes an inhibition of the baroreflex response to BVE. Therefore, the present study suggests the involvement of the serotonergic system in the modulation of vagal reflex response at PVN in the normotensive rats. Expansão de volume extracelular (EVEC) promove alterações da atividade simpática e parassimpática no coração e vasos sanguíneos, os quais podem ser moduladas por vias serotoninérgicas. Avaliar o efeito da administração de salina ou agonista serotonin

  4. A Bivariate Mixture Model for Natural Antibody Levels to Human Papillomavirus Types 16 and 18: Baseline Estimates for Monitoring the Herd Effects of Immunization.

    Directory of Open Access Journals (Sweden)

    Margaretha A Vink

    Full Text Available Post-vaccine monitoring programs for human papillomavirus (HPV have been introduced in many countries, but HPV serology is still an underutilized tool, partly owing to the weak antibody response to HPV infection. Changes in antibody levels among non-vaccinated individuals could be employed to monitor herd effects of immunization against HPV vaccine types 16 and 18, but inference requires an appropriate statistical model. The authors developed a four-component bivariate mixture model for jointly estimating vaccine-type seroprevalence from correlated antibody responses against HPV16 and -18 infections. This model takes account of the correlation between HPV16 and -18 antibody concentrations within subjects, caused e.g. by heterogeneity in exposure level and immune response. The model was fitted to HPV16 and -18 antibody concentrations as measured by a multiplex immunoassay in a large serological survey (3,875 females carried out in the Netherlands in 2006/2007, before the introduction of mass immunization. Parameters were estimated by Bayesian analysis. We used the deviance information criterion for model selection; performance of the preferred model was assessed through simulation. Our analysis uncovered elevated antibody concentrations in doubly as compared to singly seropositive individuals, and a strong clustering of HPV16 and -18 seropositivity, particularly around the age of sexual debut. The bivariate model resulted in a more reliable classification of singly and doubly seropositive individuals than achieved by a combination of two univariate models, and suggested a higher pre-vaccine HPV16 seroprevalence than previously estimated. The bivariate mixture model provides valuable baseline estimates of vaccine-type seroprevalence and may prove useful in seroepidemiologic assessment of the herd effects of HPV vaccination.

  5. The approximation of bivariate Chlodowsky-Szász-Kantorovich-Charlier-type operators

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    Purshottam Narain Agrawal

    2017-08-01

    Full Text Available Abstract In this paper, we introduce a bivariate Kantorovich variant of combination of Szász and Chlodowsky operators based on Charlier polynomials. Then, we study local approximation properties for these operators. Also, we estimate the approximation order in terms of Peetre’s K-functional and partial moduli of continuity. Furthermore, we introduce the associated GBS-case (Generalized Boolean Sum of these operators and study the degree of approximation by means of the Lipschitz class of Bögel continuous functions. Finally, we present some graphical examples to illustrate the rate of convergence of the operators under consideration.

  6. Bivariate Drought Analysis Using Streamflow Reconstruction with Tree Ring Indices in the Sacramento Basin, California, USA

    Directory of Open Access Journals (Sweden)

    Jaewon Kwak

    2016-03-01

    Full Text Available Long-term streamflow data are vital for analysis of hydrological droughts. Using an artificial neural network (ANN model and nine tree-ring indices, this study reconstructed the annual streamflow of the Sacramento River for the period from 1560 to 1871. Using the reconstructed streamflow data, the copula method was used for bivariate drought analysis, deriving a hydrological drought return period plot for the Sacramento River basin. Results showed strong correlation among drought characteristics, and the drought with a 20-year return period (17.2 million acre-feet (MAF per year in the Sacramento River basin could be considered a critical level of drought for water shortages.

  7. A non-parametric conditional bivariate reference region with an application to height/weight measurements on normal girls

    DEFF Research Database (Denmark)

    Petersen, Jørgen Holm

    2009-01-01

    A conceptually simple two-dimensional conditional reference curve is described. The curve gives a decision basis for determining whether a bivariate response from an individual is "normal" or "abnormal" when taking into account that a third (conditioning) variable may influence the bivariate resp......-dimensional response. An example that will serve to motivate and illustrate the reference is the study of the height/weight distribution of 7-8-year-old Danish school girls born in 1930, 1950, or 1970....

  8. The effects of the intake of an isotonic sports drink before orienteering competitions on skeletal muscle damage.

    Science.gov (United States)

    Colakoglu, Filiz Fatma; Cayci, Banu; Yaman, Metin; Karacan, Selma; Gonulateş, Suleyman; Ipekoglu, Gökhan; Er, Fatmanur

    2016-11-01

    [Purpose] The purpose of this study was to investigate the effects of the intake of an isotonic sports drink (500 ml water, 32 gr carbonhydrate, 120 mg calcium, 248 mg chloride, 230 mg sodium) the level of the skeletal muscle damage of orienteering athletes. [Subjects and Methods] The study was carried out on 21 male elite orienteering athletes. The athletes were divided into two groups by randomized double-blind selection. The experimental group (n=11) was given the isotonic sports drink, while the placebo group (n=10) was given 500 ml pure water. Blood samples were taken pre-competition, post-competition, 2 hours post-competition and 24 hours post-competition. [Results] The pre-c troponin, myoglobin and creatinine kinase serum levels of the placebo group were significantly lower than the post-competition and 2 hours post-competition values. The 24 hours post-competition levels of the same analyses were also significantly lower than the post-c and 2 hours post-competition. The pre-competition troponin, myoglobin and creatinine kinase levels of the experimental group were found to be significantly lower than the post-competition, 2 hours post-competition 24 hours post-competition values. In conclusion, the present results suggest that the intake of supportive sports drinks before exercising significantly prevents the observed muscle damage. The study showed that serum myoglobin levels between the experimental and the placebo group is significantly different during the 2 hours post-competition period. [Conclusion] The level of serum creatinine kinase and myoglobin accurately shows the extent of the muscle damage. However, further studies on the effect of isotonic sports drink in different training programs on the cell membrane and the muscle damage are needed.

  9. Hypotonic contrast media is more toxic than isotonic contrast media on endothelial cells in vivo and in vitro.

    Science.gov (United States)

    Ren, Lihui; Wang, Ping; Wang, Zuoyan; Liu, Yong; Lv, Shuzheng

    2017-10-01

    The aim of the current study was to investigate the cytotoxic effects of hypotonic (iopamidol) and isotonic (iodixanol) contract media (CMs) in vitro and in vivo. A total of 60 Wistar rats were included and were randomly divided into three groups (20 rats per group). Iodixanol (4 g iodine/kg), iopamidol (4 g iodine/kg) or equal volume of normal saline was injected via tail vein. HUVEC and H5V cell viability was determined by Cell Counting Kit‑8 agents. Western blotting was performed to detect ATP‑binding cassette subfamily G member 1 (ABCG1) expression. For histological analysis, hematoxylin and eosin staining was performed. Plasma endothelin, von Willebrand factor, tissue type plasminogen activator, plasminogen activator inhibitor, D‑Dimer, fibrinogen, anti‑thrombin III, plasminogen and nitric oxide synthase (NOS) were measured by using ELISA. Both iopamidol and iodixanol treatments deceased cell viability and increased apoptosis of HUVEC and H5V cells, along with downregulated NOS and ABCG1. The injection of iopamidol or iodixanol into rats changed the endothelium‑related plasma levels of biomarkers, including endothelin, von Willebrand factor, tissue type plasminogen activator, plasminogen activator inhibitor, D‑Dimer, fibrinogen and anti‑thrombin III. However, endothelia isolated from rat abdominal aorta in the iodixanol group retained their normal structure, whereas endothelial structure in the iopamidol group was injured and disrupted. The findings in the present study suggested that both hypotonic and isotonic CMs may lead to endothelial dysfunction and thrombin and fibrinolytic system disorder. However, hypotonic CMs may be more toxic than isotonic CMs. Therefore, additional cautions should be taken when selecting hypotonic CMs and their dosages during cardioangiography.

  10. Evaluation of the amount and stability of B group vitamins and vitamin C in power and isotonic beverages

    OpenAIRE

    Castro, Fernanda J. de; Rodrigo Scherer; Helena T. Godoy

    2006-01-01

    Vitamin C stability and concentration was evaluated in isotonic beverages and B group vitamins (B1, B2, B3, B5 and B6) in power beverages. The amount of vitamins was found to be above of that declared on the labels, even after the shelf life had been exceeded. A small decrease in the amount of B group vitamins was observed during the shelf life of the products. In the case of vitamin C this decrease was slightly higher. The present research shows the need of increased quality control and insp...

  11. Awareness and acceptability of human papillomavirus vaccine: an application of the instrumental variables bivariate probit model.

    Science.gov (United States)

    Do, Young Kyung; Wong, Ker Yi

    2012-01-13

    Although lower uptake rates of the human papillomavirus (HPV) vaccine among socioeconomically disadvantaged populations have been documented, less is known about the relationships between awareness and acceptability, and other factors affecting HPV vaccine uptake.The current study aimed to estimate the potential effectiveness of increased HPV vaccine awareness on the acceptability of HPV vaccination in a nationally representative sample of women, using a methodology that controlled for potential non-random selection. This study used a population-based sample from the 2007 Health Information National Trends Survey, a cross-sectional study of the US population aged 18 years or older, and focused on the subsample of 742 women who have any female children under the age of 18 years in the household. An instrumental variables bivariate probit model was used to jointly estimate HPV vaccine awareness and acceptability. The proportion of HPV vaccine acceptability among the previously aware and non-aware groups was 58% and 47%, respectively. Results from the instrumental variables bivariate probit model showed that the estimated marginal effect of awareness on acceptability was 46 percentage points, an effect that was even greater than observed. Among populations who are not currently aware of the HPV vaccine, the potential impact of raising awareness on acceptability of HPV vaccination is substantial. This finding provides additional support to strengthening public health programs that increase awareness and policy efforts that address barriers to HPV vaccination.

  12. Semiparametric probit models with univariate and bivariate current-status data.

    Science.gov (United States)

    Liu, Hao; Qin, Jing

    2017-04-24

    Multivariate current-status data are frequently encountered in biomedical and public health studies. Semiparametric regression models have been extensively studied for univariate current-status data, but most existing estimation procedures are computationally intensive, involving either penalization or smoothing techniques. It becomes more challenging for the analysis of multivariate current-status data. In this article, we study the maximum likelihood estimations for univariate and bivariate current-status data under the semiparametric probit regression models. We present a simple computational procedure combining the expectation-maximization algorithm with the pool-adjacent-violators algorithm for solving the monotone constraint on the baseline function. Asymptotic properties of the maximum likelihood estimators are investigated, including the calculation of the explicit information bound for univariate current-status data, as well as the asymptotic consistency and convergence rate for bivariate current-status data. Extensive simulation studies showed that the proposed computational procedures performed well under small or moderate sample sizes. We demonstrate the estimation procedure with two real data examples in the areas of diabetic and HIV research. © 2017, The International Biometric Society.

  13. Issues concerning Landowner Management Plan Adoption Decisions: A Recursive Bivariate Probit Approach

    Directory of Open Access Journals (Sweden)

    Omkar Joshi

    2015-01-01

    Full Text Available Despite the likely benefits of having a written forest management plan, a small number of landowners in the United States have the one. A recursive bivariate probit model was used to identify the possible relationship between landowners’ decision to obtain a management plan and their interest in future timber harvesting. Our study results based on recursive bivariate model suggest that landowners having larger land ownerships, longer forest ownership tenure, and higher education were more likely to have a forest management plan and future timber harvesting interest. While the landowners having interest for wildlife management were also interested to have a written management plan, they did not prefer to harvest in future. Study results indicate that written management plan means more than a timber harvesting strategy to landowners in general. Many elderly landowners with a low level of income and less formal education and those having small or medium sized tracts of forestland are less likely to own a written management plan. Therefore, this group requires special attention in various government sponsored forest management related extension activities. Future research on understanding landowner perception behind written management plan is recommended.

  14. A bivariate extension of the Hosking and Wallis goodness-of-fit measure for regional distributions

    Science.gov (United States)

    Kjeldsen, T. R.; Prosdocimi, I.

    2015-02-01

    This study presents a bivariate extension of the goodness-of-fit measure for regional frequency distributions developed by Hosking and Wallis (1993) for use with the method of L-moments. Utilizing the approximate joint normal distribution of the regional L-skewness and L-kurtosis, a graphical representation of the confidence region on the L-moment diagram can be constructed as an ellipsoid. Candidate distributions can then be accepted where the corresponding theoretical relationship between the L-skewness and L-kurtosis intersects the confidence region, and the chosen distribution would be the one that minimizes the Mahalanobis distance measure. Based on a set of Monte Carlo simulations, it is demonstrated that the new bivariate measure generally selects the true population distribution more frequently than the original method. Results are presented to show that the new measure remains robust when applied to regions where the level of intersite correlation is at a level found in real world regions. Finally the method is applied to two different case studies involving annual maximum peak flow data from Italian and British catchments to identify suitable regional frequency distributions.

  15. A method of moments to estimate bivariate survival functions: the copula approach

    Directory of Open Access Journals (Sweden)

    Silvia Angela Osmetti

    2013-05-01

    Full Text Available In this paper we discuss the problem on parametric and non parametric estimation of the distributions generated by the Marshall-Olkin copula. This copula comes from the Marshall-Olkin bivariate exponential distribution used in reliability analysis. We generalize this model by the copula and different marginal distributions to construct several bivariate survival functions. The cumulative distribution functions are not absolutely continuous and they unknown parameters are often not be obtained in explicit form. In order to estimate the parameters we propose an easy procedure based on the moments. This method consist in two steps: in the first step we estimate only the parameters of marginal distributions and in the second step we estimate only the copula parameter. This procedure can be used to estimate the parameters of complex survival functions in which it is difficult to find an explicit expression of the mixed moments. Moreover it is preferred to the maximum likelihood one for its simplex mathematic form; in particular for distributions whose maximum likelihood parameters estimators can not be obtained in explicit form.

  16. A non-stationary cost-benefit based bivariate extreme flood estimation approach

    Science.gov (United States)

    Qi, Wei; Liu, Junguo

    2018-02-01

    Cost-benefit analysis and flood frequency analysis have been integrated into a comprehensive framework to estimate cost effective design values. However, previous cost-benefit based extreme flood estimation is based on stationary assumptions and analyze dependent flood variables separately. A Non-Stationary Cost-Benefit based bivariate design flood estimation (NSCOBE) approach is developed in this study to investigate influence of non-stationarities in both the dependence of flood variables and the marginal distributions on extreme flood estimation. The dependence is modeled utilizing copula functions. Previous design flood selection criteria are not suitable for NSCOBE since they ignore time changing dependence of flood variables. Therefore, a risk calculation approach is proposed based on non-stationarities in both marginal probability distributions and copula functions. A case study with 54-year observed data is utilized to illustrate the application of NSCOBE. Results show NSCOBE can effectively integrate non-stationarities in both copula functions and marginal distributions into cost-benefit based design flood estimation. It is also found that there is a trade-off between maximum probability of exceedance calculated from copula functions and marginal distributions. This study for the first time provides a new approach towards a better understanding of influence of non-stationarities in both copula functions and marginal distributions on extreme flood estimation, and could be beneficial to cost-benefit based non-stationary bivariate design flood estimation across the world.

  17. Bivariate EMD-Based Data Adaptive Approach to the Analysis of Climate Variability

    Directory of Open Access Journals (Sweden)

    Md. Khademul Islam Molla

    2011-01-01

    Full Text Available This paper presents a data adaptive approach for the analysis of climate variability using bivariate empirical mode decomposition (BEMD. The time series of climate factors: daily evaporation, maximum and minimum temperatures are taken into consideration in variability analysis. All climate data are collected from a specific area of Bihar in India. Fractional Gaussian noise (fGn is used here as the reference signal. The climate signal and fGn (of same length are combined to produce bivariate (complex signal which is decomposed using BEMD into a finite number of sub-band signals named intrinsic mode functions (IMFs. Both of climate signal as well as fGn are decomposed together into IMFs. The instantaneous frequencies and Fourier spectrum of IMFs are observed to illustrate the property of BEMD. The lowest frequency oscillation of climate signal represents the annual cycle (AC which is an important factor in analyzing climate change and variability. The energies of the fGn's IMFs are used to define the data adaptive threshold to separate AC. The IMFs of climate signal with energy exceeding such threshold are summed up to separate the AC. The interannual distance of climate signal is also illustrated for better understanding of climate change and variability.

  18. Self-Consistent Nonparametric Maximum Likelihood Estimator of the Bivariate Survivor Function.

    Science.gov (United States)

    Prentice, R L

    2014-09-01

    As usually formulated the nonparametric likelihood for the bivariate survivor function is over-parameterized, resulting in uniqueness problems for the corresponding nonparametric maximum likelihood estimator. Here the estimation problem is redefined to include parameters for marginal hazard rates, and for double failure hazard rates only at informative uncensored failure time grid points where there is pertinent empirical information. Double failure hazard rates at other grid points in the risk region are specified rather than estimated. With this approach the nonparametric maximum likelihood estimator is unique, and can be calculated using a two-step procedure. The first step involves setting aside all doubly censored observations that are interior to the risk region. The nonparametric maximum likelihood estimator from the remaining data turns out to be the Dabrowska (1988) estimator. The omitted doubly censored observations are included in the procedure in the second stage using self-consistency, resulting in a non-iterative nonpara-metric maximum likelihood estimator for the bivariate survivor function. Simulation evaluation and asymptotic distributional results are provided. Moderate sample size efficiency for the survivor function nonparametric maximum likelihood estimator is similar to that for the Dabrowska estimator as applied to the entire dataset, while some useful efficiency improvement arises for corresponding distribution function estimator, presumably due to the avoidance of negative mass assignments.

  19. Artificial neural networks versus bivariate logistic regression in prediction diagnosis of patients with hypertension and diabetes.

    Science.gov (United States)

    Adavi, Mehdi; Salehi, Masoud; Roudbari, Masoud

    2016-01-01

    Diabetes and hypertension are important non-communicable diseases and their prevalence is important for health authorities. The aim of this study was to determine the predictive precision of the bivariate Logistic Regression (LR) and Artificial Neutral Network (ANN) in concurrent diagnosis of diabetes and hypertension. This cross-sectional study was performed with 12000 Iranian people in 2013 using stratified- cluster sampling. The research questionnaire included information on hypertension and diabetes and their risk factors. A perceptron ANN with two hidden layers was applied to data. To build a joint LR model and ANN, SAS 9.2 and Matlab software were used. The AUC was used to find the higher accurate model for predicting diabetes and hypertension. The variables of gender, type of cooking oil, physical activity, family history, age, passive smokers and obesity entered to the LR model and ANN. The odds ratios of affliction to both diabetes and hypertension is high in females, users of solid oil, with no physical activity, with positive family history, age of equal or higher than 55, passive smokers and those with obesity. The AUC for LR model and ANN were 0.78 (p=0.039) and 0.86 (p=0.046), respectively. The best model for concurrent affliction to hypertension and diabetes is ANN which has higher accuracy than the bivariate LR model.

  20. Xp21 contiguous gene syndromes: Deletion quantitation with bivariate flow karyotyping allows mapping of patient breakpoints

    Energy Technology Data Exchange (ETDEWEB)

    McCabe, E.R.B.; Towbin, J.A. (Baylor College of Medicine, Houston, TX (United States)); Engh, G. van den; Trask, B.J. (Lawrence Livermore National Lab., CA (United States))

    1992-12-01

    Bivariate flow karyotyping was used to estimate the deletion sizes for a series of patients with Xp21 contiguous gene syndromes. The deletion estimates were used to develop an approximate scale for the genomic map in Xp21. The bivariate flow karyotype results were compared with clinical and molecular genetic information on the extent of the patients' deletions, and these various types of data were consistent. The resulting map spans >15 Mb, from the telomeric interval between DXS41 (99-6) and DXS68 (1-4) to a position centromeric to the ornithine transcarbamylase locus. The deletion sizing was considered to be accurate to [plus minus]1 Mb. The map provides information on the relative localization of genes and markers within this region. For example, the map suggests that the adrenal hypoplasia congenita and glycerol kinase genes are physically close to each other, are within 1-2 Mb of the telomeric end of the Duchenne muscular dystrophy (DMD) gene, and are nearer to the DMD locus than to the more distal marker DXS28 (C7). Information of this type is useful in developing genomic strategies for positional cloning in Xp21. These investigations demonstrate that the DNA from patients with Xp21 contiguous gene syndromes can be valuable reagents, not only for ordering loci and markers but also for providing an approximate scale to the map of the Xp21 region surrounding DMD. 44 refs., 3 figs.

  1. A comparison of isometric, isotonic concentric and isotonic eccentric exercises in the physiotherapy management of subacromial pain syndrome/rotator cuff tendinopathy: study protocol for a pilot randomised controlled trial.

    Science.gov (United States)

    Kinsella, Rita; Cowan, Sallie M; Watson, Lyn; Pizzari, Tania

    2017-01-01

    Subacromial pain syndrome (SPS) involving rotator cuff tendinopathy is a common cause of shoulder pain and disability. Evidence suggests that structured physiotherapy may be as effective as surgery in this condition with significant improvements demonstrated in trials involving scapular retraining, rotator cuff strengthening and flexibility exercises. Most published programs typically utilise isotonic concentric and/or eccentric strengthening modes. Recently, immediate analgesic effects and muscle strength gains following heavy-load isometric exercises in lower limb tendinopathy conditions have been observed. It is pertinent to ascertain whether such outcomes can be replicated in SPS/rotator cuff tendinopathy. The primary aim of this study is to establish the feasibility of undertaking a full-scale randomised controlled trial (RCT) that compares the effects of isometric, isotonic concentric and isotonic eccentric rotator cuff contractions when used as part of a semi-standardised exercise-based physiotherapy program in patients diagnosed with SPS. The secondary aim is to explore potential trends or treatment effects of the exercise intervention. Thirty-six participants diagnosed with SPS will be randomised to one of three intervention groups and undergo a one-on-one exercise-based physiotherapy intervention, involving scapular and rotator cuff muscle retraining and strengthening. Each group will utilise a different mode of rotator cuff strengthening-isometric, isotonic concentric or isotonic eccentric. Rotator cuff tendon responses to isometric loading are not yet established in the literature; hence, individualised, progressive loading will be used in this pilot study in accordance with symptoms. The intervention will involve two phases: during Phase 1 (weeks 1-6) participants undertake the active group-specific physiotherapy treatment; in Phase 2 (weeks 6-12), they undertake a progressive, but no longer group-specific exercise program. To determine feasibility, an

  2. Improvement in muscle strength with low-load isotonic training depends on fascicle length but not joint angle.

    Science.gov (United States)

    Tanaka, Hiroki; Ikezoe, Tome; Nakamura, Masatoshi; Yanase, Ko; Fujita, Kosuke; Motomura, Yoshiki; Kusano, Ken; Araki, Kojiro; Umehara, Jun; Saeki, Junya; Morishita, Katsuyuki; Ichihashi, Noriaki

    2018-01-01

    In this study we investigate whether low-load isotonic training will elicit greater improvement in muscle strength at the same fascicle length, rather than at the same joint angle. Sixteen healthy men (24.1 ± 2.5 years of age) were randomly divided into intervention and control groups. Pre- and posttraining maximum isometric and isokinetic strengths and fascicle lengths of the medial gastrocnemius muscle were measured. Isotonic resistance training at 15 ° to 30 ° ankle plantarflexion at low intensity was conducted for 4 weeks. The maximum isometric and isokinetic strength of the intervention group increased significantly only at 15 ° dorsiflexion and 8 ° to 12 ° dorsiflexion. Fascicle length during maximum voluntary contraction at 15 ° dorsiflexion to 0 ° was similar to fascicle length under training conditions. It is possible that the improvement in muscle strength with low-load training depends on fascicle length rather than joint angle. Muscle Nerve 57: 83-89, 2018. © 2017 Wiley Periodicals, Inc.

  3. Level structure of 141Ba and 139Xe and the level systematics of N=85 even-odd isotones

    CERN Document Server

    Luo, Y X; Hamilton, J H; Ramayya, A V; Hwang, J K; Beyer, C J; Zhu, S J; Kormicki, J; Zhang, X Q; Jones, E F; Gore, P M; Ginter, T N; Gregorich, K E; Lee, I Y; Macchiavelli, A O; Zielinski, P M; Folden, C M; Fallon, P; Ter-Akopian, G M; Oganessian, Yu T; Daniel, A V; Stoyer, M A; Cole, J D; Donangelo, R; Wu, S C; Asztalos, S J

    2002-01-01

    New level schemes of sup 1 sup 4 sup 1 Ba and sup 1 sup 3 sup 9 Xe are proposed from the analyses of spontaneous-fission gamma data from our sup 2 sup 5 sup 2 Cf spontaneous fission Gammasphere runs of 1995 and 2000. By analogy with the N = 85 even-odd isotones sup 1 sup 4 sup 9 Gd, sup 1 sup 4 sup 7 Sm, and sup 1 sup 4 sup 5 Nd, spins and parities were assigned to the observed excited states in sup 1 sup 4 sup 1 Ba and sup 1 sup 3 sup 9 Xe. It appears that spherical shell model neutron excitations plus octupolephonons are an appropriate basis at the lower end of the bands. Going to higher spins it is clear that the soft rotor involving valence protons as well as neutrons becomes increasingly important in the configurations. Level systematics in the N = 85 even-odd isotones from Gd(Z=64) through Te(Z=52), are discussed. The excitation systematics and smooth trends of the analogous levels support the spin and parity assignment for excited levels observed in sup 1 sup 4 sup 1 Ba and sup 1 sup 3 sup 9 Xe. The le...

  4. Obtaining DDF Curves of Extreme Rainfall Data Using Bivariate Copula and Frequency Analysis

    Science.gov (United States)

    Sadri, S.; Madsen, H.; Mikkelsen, P. S.; Burn, D. H.

    2009-05-01

    The traditional rainfall intensity-duration-frequency (IDF) curve is a reliable approach for representing the variation of rainfall intensity with duration for a given return period. In reality rainfall variables intensity, depth and duration are dependent and therefore a bivariate analysis using copulas can give a more accurate IDF curve. We study IDF curves using a copula in a bivariate frequency analysis of extreme rainfall. To be able to choose the most suitable copula among candidate copulas (i.e., Gumbel, Clayton, and Frank) we demonstrated IDF curves based on variation of depth with duration for a given return period and name them DDF (depth-duration-frequency) curves. The copula approach does not assume the rainfall variables are independent or jointly normally distributed. Rainfall series are extracted in three ways: (1) by maximum mean intensity; (2) by depth and duration of individual rainfall events; and (3) by storage volume and duration. In each case we used partial duration series (PDS) to extract extreme rainfall variables. The DDF curves derived from each method are presented and compared. This study examines extreme rainfall data from catchment Vedbæ k Renseanlæ g, situated near Copenhagen in Denmark. For rainfall extracted using method 2, the marginal distribution of depth was found to fit the Generalized Pareto distribution while duration was found to fit the Gamma distribution, using the method of L-moments. The volume was fit with a generalized Pareto distribution and the duration was fit with a Pearson type III distribution for rainfall extracted using method 3. The Clayton copula was found to be appropriate for bivariate analysis of rainfall depth and duration for both methods 2 and 3. DDF curves derived using the Clayton copula for depth and duration of individual rainfall events (method 2) are in agreement with empirically derived DDF curves obtained from maximum mean intensity (method 1) for a 10-year return period. For a 100-year

  5. Bayesian neural networks for bivariate binary data: an application to prostate cancer study.

    Science.gov (United States)

    Chakraborty, Sounak; Ghosh, Malay; Maiti, Tapabrata; Tewari, Ashutosh

    2005-12-15

    Prostate cancer is one of the most common cancers in American men. The cancer could either be locally confined, or it could spread outside the organ. When locally confined, there are several options for treating and curing this disease. Otherwise, surgery is the only option, and in extreme cases of outside spread, it could very easily recur within a short time even after surgery and subsequent radiation therapy. Hence, it is important to know, based on pre-surgery biopsy results how likely the cancer is organ-confined or not. The paper considers a hierarchical Bayesian neural network approach for posterior prediction probabilities of certain features indicative of non-organ confined prostate cancer. In particular, we find such probabilities for margin positivity (MP) and seminal vesicle (SV) positivity jointly. The available training set consists of bivariate binary outcomes indicating the presence or absence of the two. In addition, we have certain covariates such as prostate specific antigen (PSA), gleason score and the indicator for the cancer to be unilateral or bilateral (i.e. spread on one or both sides) in one data set and gene expression microarrays in another data set. We take a hierarchical Bayesian neural network approach to find the posterior prediction probabilities for a test and validation set, and compare these with the actual outcomes for the first data set. In case of the microarray data we use leave one out cross-validation to access the accuracy of our method. We also demonstrate the superiority of our method to the other competing methods through a simulation study. The Bayesian procedure is implemented by an application of the Markov chain Monte Carlo numerical integration technique. For the problem at hand, our Bayesian bivariate neural network procedure is shown to be superior to the classical neural network, Radford Neal's Bayesian neural network as well as bivariate logistic models to predict jointly the MP and SV in a patient in both the

  6. Applied multivariate statistics with R

    CERN Document Server

    Zelterman, Daniel

    2015-01-01

    This book brings the power of multivariate statistics to graduate-level practitioners, making these analytical methods accessible without lengthy mathematical derivations. Using the open source, shareware program R, Professor Zelterman demonstrates the process and outcomes for a wide array of multivariate statistical applications. Chapters cover graphical displays, linear algebra, univariate, bivariate and multivariate normal distributions, factor methods, linear regression, discrimination and classification, clustering, time series models, and additional methods. Zelterman uses practical examples from diverse disciplines to welcome readers from a variety of academic specialties. Those with backgrounds in statistics will learn new methods while they review more familiar topics. Chapters include exercises, real data sets, and R implementations. The data are interesting, real-world topics, particularly from health and biology-related contexts. As an example of the approach, the text examines a sample from the B...

  7. A composite likelihood method for bivariate meta-analysis in diagnostic systematic reviews.

    Science.gov (United States)

    Chen, Yong; Liu, Yulun; Ning, Jing; Nie, Lei; Zhu, Hongjian; Chu, Haitao

    2017-04-01

    Diagnostic systematic review is a vital step in the evaluation of diagnostic technologies. In many applications, it involves pooling pairs of sensitivity and specificity of a dichotomized diagnostic test from multiple studies. We propose a composite likelihood (CL) method for bivariate meta-analysis in diagnostic systematic reviews. This method provides an alternative way to make inference on diagnostic measures such as sensitivity, specificity, likelihood ratios, and diagnostic odds ratio. Its main advantages over the standard likelihood method are the avoidance of the nonconvergence problem, which is nontrivial when the number of studies is relatively small, the computational simplicity, and some robustness to model misspecifications. Simulation studies show that the CL method maintains high relative efficiency compared to that of the standard likelihood method. We illustrate our method in a diagnostic review of the performance of contemporary diagnostic imaging technologies for detecting metastases in patients with melanoma.

  8. A bivariate whole-genome linkage scan suggests several shared genomic regions for obesity and osteoporosis.

    Science.gov (United States)

    Tang, Zi-Hui; Xiao, Peng; Lei, Shu-Feng; Deng, Fei-Yan; Zhao, Lan-Juan; Deng, Hong-Yi; Tan, Li-Jun; Shen, Hui; Xiong, Dong-Hai; Recker, Robert R; Deng, Hong-Wen

    2007-07-01

    A genome-wide bivariate analysis was conducted for body fat mass (BFM) and bone mineral density (BMD) in a large Caucasian sample. We found some quantitative trait loci shared by BFM and BMD in the total sample and the gender-specific subgroups, and quantitative trait loci with potential pleiotropy were disclosed. BFM and BMD, as the respective measure for obesity and osteoporosis, are phenotypically and genetically correlated. However, specific genomic regions accounting for their genetic correlation are unknown. To identify systemically the shared genomic regions for BFM and BMD, we performed a bivariate whole-genome linkage scan in 4498 Caucasian individuals from 451 families for BFM and BMD at the hip, spine, and wrist, respectively. Linkage analyses were performed in the total sample and the male and female subgroups, respectively. In the entire sample, suggestive linkages were detected at 7p22-p21 (LOD 2.69) for BFM and spine BMD, 6q27 (LOD 2.30) for BFM and hip BMD, and 11q13 (LOD 2.64) for BFM and wrist BMD. Male-specific suggestive linkages were found at 13q12 (LOD 3.23) for BFM and spine BMD and at 7q21 (LOD 2.59) for BFM and hip BMD. Female-specific suggestive LOD scores were 3.32 at 15q13 for BFM and spine BMD and 3.15 at 6p25-24 for BFM and wrist BMD. Several shared genomic regions for BFM and BMD were identified here. Our data may benefit further positional and functional studies, aimed at eventually uncovering the complex mechanism underlying the shared genetic determination of obesity and osteoporosis.

  9. A bivariate contaminated binormal model for robust fitting of proper ROC curves to a pair of correlated, possibly degenerate, ROC datasets.

    Science.gov (United States)

    Zhai, Xuetong; Chakraborty, Dev P

    2017-06-01

    The objective was to design and implement a bivariate extension to the contaminated binormal model (CBM) to fit paired receiver operating characteristic (ROC) datasets-possibly degenerate-with proper ROC curves. Paired datasets yield two correlated ratings per case. Degenerate datasets have no interior operating points and proper ROC curves do not inappropriately cross the chance diagonal. The existing method, developed more than three decades ago utilizes a bivariate extension to the binormal model, implemented in CORROC2 software, which yields improper ROC curves and cannot fit degenerate datasets. CBM can fit proper ROC curves to unpaired (i.e., yielding one rating per case) and degenerate datasets, and there is a clear scientific need to extend it to handle paired datasets. In CBM, nondiseased cases are modeled by a probability density function (pdf) consisting of a unit variance peak centered at zero. Diseased cases are modeled with a mixture distribution whose pdf consists of two unit variance peaks, one centered at positive μ with integrated probability α, the mixing fraction parameter, corresponding to the fraction of diseased cases where the disease was visible to the radiologist, and one centered at zero, with integrated probability (1-α), corresponding to disease that was not visible. It is shown that: (a) for nondiseased cases the bivariate extension is a unit variances bivariate normal distribution centered at (0,0) with a specified correlation ρ1 ; (b) for diseased cases the bivariate extension is a mixture distribution with four peaks, corresponding to disease not visible in either condition, disease visible in only one condition, contributing two peaks, and disease visible in both conditions. An expression for the likelihood function is derived. A maximum likelihood estimation (MLE) algorithm, CORCBM, was implemented in the R programming language that yields parameter estimates and the covariance matrix of the parameters, and other statistics. A

  10. Cancer Statistics

    Science.gov (United States)

    ... What Is Cancer? Cancer Statistics Cancer Disparities Cancer Statistics Cancer has a major impact on society in ... success of efforts to control and manage cancer. Statistics at a Glance: The Burden of Cancer in ...

  11. Caregiving Statistics

    Science.gov (United States)

    ... Coping with Alzheimer’s COPD Caregiving Take Care! Caregiver Statistics Statistics on Family Caregivers and Family Caregiving Caregiving Population ... Health Care Caregiver Self-Awareness State by State Statistics Caregiving Population The value of the services family ...

  12. Lowest excited 2+ and 3- states in even-A N =82 and N =126 isotones from relativistic quasiparticle random-phase approximation

    Science.gov (United States)

    Ansari, A.

    2017-05-01

    Excitation energy, reduced transition rates, and g factors of the lowest 2+ and 3- states of even-even N =82 and N =126 isotones are studied in relativistic QRPA formalism. These values are compared to available experimental data and some of the recent theoretical results. In the following the obtained results are presented first for N =82 isotones with Z =36 -72 , that is very neutron-rich to neutron-deficient nuclei with N /Z varying from 2.28 to 1.14 and then for N =126 isotones with Z =76 -92 . These calculations are performed employing NL3, as well as its recently revised version NL 3* set of the RMF Lagrangian parameters. It is found that both the interaction sets produce almost similar results. The agreement with available data is rather satisfactory in view of such a wide range of nuclei considered here, though there are serious disagreements like in the case of 140Ce and properties of 3- states of N =126 isotones.

  13. The relationship between isotonic plantar flexor endurance, navicular drop, and exercise-related leg pain in a cohort of collegiate cross-country runners.

    Science.gov (United States)

    Bennett, Jason E; Reinking, Mark F; Rauh, Mitchell J

    2012-06-01

    The purpose of this study was to examine the relationships between isotonic ankle plantar flexor endurance (PFE), foot pronation as measured by navicular drop, and exercise-related leg pain (ERLP). Exercise-related leg pain is a common occurrence in competitive and recreational runners. The identification of factors contributing to the development of ERLP may help guide methods for the prevention and management of overuse injuries. Seventy-seven (44 males, 33 females) competitive runners from five collegiate cross-country (XC) teams consented to participate in the study. Isotonic ankle PFE and foot pronation were measured using the standing heel-rise and navicular drop (ND) tests, respectively. Demographic information, anthropometric measurements, and ERLP history were also recorded. Subjects were then prospectively tracked for occurrence of ERLP during the 2009 intercollegiate cross-country season. Multivariate logistic regression analysis was used to examine the relationships between isotonic ankle joint PFE and ND and the occurrence of ERLP. While no significant differences were identified for isotonic ankle PFE between groups of collegiate XC runners with and without ERLP, runners with a ND >10 mm were almost 7 times (OR=6.6, 95% CI=1.2-38.0) more likely to incur medial ERLP than runners with ND risk factor in the development of ERLP in this group of collegiate XC runners, those with a ND greater than 10 mm may be at greater odds of incurring medial ERLP. 2b.

  14. Spin-orbit splittings of neutron states in N =20 isotones from covariant density functionals and their extensions

    Science.gov (United States)

    Karakatsanis, Konstantinos; Lalazissis, G. A.; Ring, Peter; Litvinova, Elena

    2017-03-01

    Spin-orbit splitting is an essential ingredient for our understanding of the shell structure in nuclei. One of the most important advantages of relativistic mean-field (RMF) models in nuclear physics is the fact that the large spin-orbit (SO) potential emerges automatically from the inclusion of Lorentz-scalar and -vector potentials in the Dirac equation. It is therefore of great importance to compare the results of such models with experimental data. We investigate the size of 2 p and 1 f splittings for the isotone chain 40Ca, 38Ar, 36S, and 34Si in the framework of various relativistic and nonrelativistic density functionals. They are compared with the results of nonrelativistic models and with recent experimental data.

  15. Dynamics of intracranial electroencephalographic recordings from epilepsy patients using univariate and bivariate recurrence networks.

    Science.gov (United States)

    Subramaniyam, Narayan Puthanmadam; Hyttinen, Jari

    2015-02-01

    Recently Andrezejak et al. combined the randomness and nonlinear independence test with iterative amplitude adjusted Fourier transform (iAAFT) surrogates to distinguish between the dynamics of seizure-free intracranial electroencephalographic (EEG) signals recorded from epileptogenic (focal) and nonepileptogenic (nonfocal) brain areas of epileptic patients. However, stationarity is a part of the null hypothesis for iAAFT surrogates and thus nonstationarity can violate the null hypothesis. In this work we first propose the application of the randomness and nonlinear independence test based on recurrence network measures to distinguish between the dynamics of focal and nonfocal EEG signals. Furthermore, we combine these tests with both iAAFT and truncated Fourier transform (TFT) surrogate methods, which also preserves the nonstationarity of the original data in the surrogates along with its linear structure. Our results indicate that focal EEG signals exhibit an increased degree of structural complexity and interdependency compared to nonfocal EEG signals. In general, we find higher rejections for randomness and nonlinear independence tests for focal EEG signals compared to nonfocal EEG signals. In particular, the univariate recurrence network measures, the average clustering coefficient C and assortativity R, and the bivariate recurrence network measure, the average cross-clustering coefficient C(cross), can successfully distinguish between the focal and nonfocal EEG signals, even when the analysis is restricted to nonstationary signals, irrespective of the type of surrogates used. On the other hand, we find that the univariate recurrence network measures, the average path length L, and the average betweenness centrality BC fail to distinguish between the focal and nonfocal EEG signals when iAAFT surrogates are used. However, these two measures can distinguish between focal and nonfocal EEG signals when TFT surrogates are used for nonstationary signals. We also

  16. Dynamics of intracranial electroencephalographic recordings from epilepsy patients using univariate and bivariate recurrence networks

    Science.gov (United States)

    Subramaniyam, Narayan Puthanmadam; Hyttinen, Jari

    2015-02-01

    Recently Andrezejak et al. combined the randomness and nonlinear independence test with iterative amplitude adjusted Fourier transform (iAAFT) surrogates to distinguish between the dynamics of seizure-free intracranial electroencephalographic (EEG) signals recorded from epileptogenic (focal) and nonepileptogenic (nonfocal) brain areas of epileptic patients. However, stationarity is a part of the null hypothesis for iAAFT surrogates and thus nonstationarity can violate the null hypothesis. In this work we first propose the application of the randomness and nonlinear independence test based on recurrence network measures to distinguish between the dynamics of focal and nonfocal EEG signals. Furthermore, we combine these tests with both iAAFT and truncated Fourier transform (TFT) surrogate methods, which also preserves the nonstationarity of the original data in the surrogates along with its linear structure. Our results indicate that focal EEG signals exhibit an increased degree of structural complexity and interdependency compared to nonfocal EEG signals. In general, we find higher rejections for randomness and nonlinear independence tests for focal EEG signals compared to nonfocal EEG signals. In particular, the univariate recurrence network measures, the average clustering coefficient C and assortativity R , and the bivariate recurrence network measure, the average cross-clustering coefficient Ccross, can successfully distinguish between the focal and nonfocal EEG signals, even when the analysis is restricted to nonstationary signals, irrespective of the type of surrogates used. On the other hand, we find that the univariate recurrence network measures, the average path length L , and the average betweenness centrality BC fail to distinguish between the focal and nonfocal EEG signals when iAAFT surrogates are used. However, these two measures can distinguish between focal and nonfocal EEG signals when TFT surrogates are used for nonstationary signals. We also

  17. Unilateral fluid absorption and effects on peak power after ingestion of commercially available hypotonic, isotonic, and hypertonic sports drinks.

    Science.gov (United States)

    Rowlands, David S; Bonetti, Darrell L; Hopkins, Will G

    2011-12-01

    Isotonic sports drinks are often consumed to offset the effects of dehydration and improve endurance performance, but hypotonic drinks may be more advantageous. The purpose of the study was to compare absorption and effects on performance of a commercially available hypotonic sports drink (Mizone Rapid: 3.9% carbohydrate [CHO], 218 mOsmol/kg) with those of an isotonic drink (PowerAde: 7.6% CHO, 281 mOsmol/ kg), a hypertonic drink (Gatorade: 6% CHO, 327 mOsmol/kg), and a noncaloric placebo (8 mOsmol/kg). In a crossover, 11 cyclists consumed each drink on separate days at 250 ml/15 min during a 2-hr preload ride at 55% peak power followed by an incremental test to exhaustion. Small to moderate increases in deuterium oxide enrichment in the preload were observed with Mizone Rapid relative to PowerAde, Gatorade, and placebo (differences of 88, 45, and 42 parts per million, respectively; 90% confidence limits ±28). Serum osmolality was moderately lower with Mizone Rapid than with PowerAde and Gatorade (-1.9, -2.4; mOsmol/L; ±1.2 mOsmol/L) but not clearly different vs. placebo. Plasma volume reduction was small to moderate with Mizone Rapid, PowerAde, and Gatorade relative to placebo (-1.9%, -2.5%, -2.9%; ± 2.5%). Gut comfort was highest with Mizone Rapid but clearly different (8.4% ± 4.8%) only vs PowerAde. Peak power was highest with Mizone Rapid (380 W) vs. placebo and other drinks (1.2-3.0%; 99% confidence limits ±4.7%), but differences were inconclusive with reference to the smallest important effect (~1.2%). The outcomes are consistent with fastest fluid absorption with the hypotonic sports drink. Further research should determine whether the effect has a meaningful impact on performance.

  18. Impact of Isotonic Beverage on the Hydration Status of Healthy Chinese Adults in Air-Conditioned Environment

    Directory of Open Access Journals (Sweden)

    Phei Ching Siow

    2017-03-01

    Full Text Available People living in tropical climates spend much of their time in confined air-conditioned spaces, performing normal daily activities. This study investigated the effect of distilled water (W or isotonic beverage (IB on the hydration status in subjects living under these conditions. In a randomized crossover design, forty-nine healthy male subjects either consumed beverage or IB over a period of 8 h (8 h in a controlled air-conditioned environment. Blood, urine, and saliva samples were collected at baseline and after 8 h. Hydration status was assessed by body mass, urine output, blood and plasma volume, fluid retention, osmolality, electrolyte concentration and salivary flow rate. In the IB group, urine output (1862 ± 86 mL vs. 2104 ± 98 mL was significantly lower and more fluids were retained (17% ± 3% vs. 7% ± 3% as compared to W (p < 0.05 after 8 h. IB also resulted in body mass gain (0.14 ± 0.06 kg, while W led to body mass loss (−0.04 ± 0.05 kg (p = 0.01. A significantly smaller drop in blood volume and lower free water clearance was observed in IB (−1.18% ± 0.43%; 0.55 ± 0.26 mL/min compared to W (−2.11% ± 0.41%; 1.35 ± 0.24 mL/min (p < 0.05. IB increased salivary flow rate (0.54 ± 0.05 g/min 0.62 ± 0.04 g/min. In indoor environments, performing routine activities and even without excessive sweating, isotonic beverages may be more effective at retaining fluids and maintaining hydration status by up to 10% compared to distilled water.

  19. Improved deadzone modeling for bivariate wavelet shrinkage-based image denoising

    Science.gov (United States)

    DelMarco, Stephen

    2016-05-01

    Modern image processing performed on-board low Size, Weight, and Power (SWaP) platforms, must provide high- performance while simultaneously reducing memory footprint, power consumption, and computational complexity. Image preprocessing, along with downstream image exploitation algorithms such as object detection and recognition, and georegistration, place a heavy burden on power and processing resources. Image preprocessing often includes image denoising to improve data quality for downstream exploitation algorithms. High-performance image denoising is typically performed in the wavelet domain, where noise generally spreads and the wavelet transform compactly captures high information-bearing image characteristics. In this paper, we improve modeling fidelity of a previously-developed, computationally-efficient wavelet-based denoising algorithm. The modeling improvements enhance denoising performance without significantly increasing computational cost, thus making the approach suitable for low-SWAP platforms. Specifically, this paper presents modeling improvements to the Sendur-Selesnick model (SSM) which implements a bivariate wavelet shrinkage denoising algorithm that exploits interscale dependency between wavelet coefficients. We formulate optimization problems for parameters controlling deadzone size which leads to improved denoising performance. Two formulations are provided; one with a simple, closed form solution which we use for numerical result generation, and the second as an integral equation formulation involving elliptic integrals. We generate image denoising performance results over different image sets drawn from public domain imagery, and investigate the effect of wavelet filter tap length on denoising performance. We demonstrate denoising performance improvement when using the enhanced modeling over performance obtained with the baseline SSM model.

  20. Bivariate frequency analysis of rainfall intensity and duration for urban stormwater infrastructure design

    Science.gov (United States)

    Jun, Changhyun; Qin, Xiaosheng; Gan, Thian Yew; Tung, Yeou-Koung; De Michele, Carlo

    2017-10-01

    This study presents a storm-event based bivariate frequency analysis approach to determine design rainfalls in which, the number, intensity and duration of actual rainstorm events were considered. To derive more realistic design storms, the occurrence probability of an individual rainstorm event was determined from the joint distribution of storm intensity and duration through a copula model. Hourly rainfall data were used at three climate stations respectively located in Singapore, South Korea and Canada. It was found that the proposed approach could give a more realistic description of rainfall characteristics of rainstorm events and design rainfalls. As results, the design rainfall quantities from actual rainstorm events at the three studied sites are consistently lower than those obtained from the conventional rainfall depth-duration-frequency (DDF) method, especially for short-duration storms (such as 1-h). It results from occurrence probabilities of each rainstorm event and a different angle for rainfall frequency analysis, and could offer an alternative way of describing extreme rainfall properties and potentially help improve the hydrologic design of stormwater management facilities in urban areas.

  1. Bivariate flow cytometric analysis and sorting of different types of maize starch grains.

    Science.gov (United States)

    Zhang, Xudong; Feng, Jiaojiao; Wang, Heng; Zhu, Jianchu; Zhong, Yuyue; Liu, Linsan; Xu, Shutu; Zhang, Renhe; Zhang, Xinghua; Xue, Jiquan; Guo, Dongwei

    2017-10-04

    Particle-size distribution, granular structure, and composition significantly affect the physicochemical properties, rheological properties, and nutritional function of starch. Flow cytometry and flow sorting are widely considered convenient and efficient ways of classifying and separating natural biological particles or other substances into subpopulations, respectively, based on the differential response of each component to stimulation by a light beam; the results allow for the correlation analysis of parameters. In this study, different types of starches isolated from waxy maize, sweet maize, high-amylose maize, pop maize, and normal maize were initially classified into various subgroups by flow cytometer and then collected through flow sorting to observe their morphology and particle-size distribution. The results showed that a 0.25% Gelzan solution served as an optimal reagent for keeping individual starch particles homogeneously dispersed in suspension for a relatively long time. The bivariate flow cytometric population distributions indicated that the starches of normal maize, sweet maize, and pop maize were divided into two subgroups, whereas high-amylose maize starch had only one subgroup. Waxy maize starch, conversely, showed three subpopulations. The subgroups sorted by flow cytometer were determined and verified in terms of morphology and granule size by scanning electron microscopy and laser particle distribution analyzer. Results showed that flow cytometry can be regarded as a novel method for classifying and sorting starch granules. © 2017 International Society for Advancement of Cytometry. © 2017 International Society for Advancement of Cytometry.

  2. Modeling both of the number of pausibacillary and multibacillary leprosy patients by using bivariate poisson regression

    Science.gov (United States)

    Winahju, W. S.; Mukarromah, A.; Putri, S.

    2015-03-01

    Leprosy is a chronic infectious disease caused by bacteria of leprosy (Mycobacterium leprae). Leprosy has become an important thing in Indonesia because its morbidity is quite high. Based on WHO data in 2014, in 2012 Indonesia has the highest number of new leprosy patients after India and Brazil with a contribution of 18.994 people (8.7% of the world). This number makes Indonesia automatically placed as the country with the highest number of leprosy morbidity of ASEAN countries. The province that most contributes to the number of leprosy patients in Indonesia is East Java. There are two kind of leprosy. They consist of pausibacillary and multibacillary. The morbidity of multibacillary leprosy is higher than pausibacillary leprosy. This paper will discuss modeling both of the number of multibacillary and pausibacillary leprosy patients as responses variables. These responses are count variables, so modeling will be conducted by using bivariate poisson regression method. Unit experiment used is in East Java, and predictors involved are: environment, demography, and poverty. The model uses data in 2012, and the result indicates that all predictors influence significantly.

  3. The Bivariate Empirical Mode Decomposition and Its Contribution to Grinding Chatter Detection

    Directory of Open Access Journals (Sweden)

    Huanguo Chen

    2017-02-01

    Full Text Available Grinding chatter reduces the long-term reliability of grinding machines. Detecting the negative effects of chatter requires improved chatter detection techniques. The vibration signals collected from grinders are mainly nonstationary, nonlinear and multidimensional. Hence, bivariate empirical mode decomposition (BEMD has been investigated as a multiple signal processing method. In this paper, a feature vector extraction method based on BEMD and Hilbert transform was applied to the problem of grinding chatter. The effectiveness of this method was tested and validated with a simulated chatter signal produced by a vibration signal generator. The extraction criterion of true intrinsic mode functions (IMFs was also investigated, as well as a method for selecting the most ideal number of projection directions using the BEMD algorithm. Moreover, real-time variance and instantaneous energy were employed as chatter feature vectors for improving the prediction of chatter. Furthermore, the combination of BEMD and Hilbert transform was validated by experimental data collected from a computer numerical control (CNC guideway grinder. The results reveal the good behavior of BEMD in terms of processing nonstationary and nonlinear signals, and indicating the synchronous characteristics of multiple signals. Extracted chatter feature vectors were demonstrated to be reliable predictors of early grinding chatter.

  4. Modelling bivariate astronomical data with multiple components and non-linear relationships

    Science.gov (United States)

    Koen, C.; Bere, A.

    2017-11-01

    A common approach towards modelling bivariate scatterplots is decomposition into Gaussian components, I.e. Gaussian mixture modelling. This implicitly assumes linear relationships between the variables within each of the components in the mixture. An alternative, namely dependence modelling by mixtures of copulas, is advocated in this paper. This approach allows separate modelling of the univariate marginal distributions and the dependence which can possibly be non-linear and/or asymmetric. It also accommodates the use of a variety of parametric families for modelling each component and for each variable. The variety of dependence structures can be extended by introducing rotated versions of the copulas. Gaussian mixture modelling on the one hand, and separate modelling of univariate marginal distributions and dependence on the other hand, are illustrated by application to pulsar period - period-derivative observations. Parameter estimation for mixtures of copulas is performed using the method of maximum likelihood and selected copula models are subjected to non-parametric goodness-of-fit testing.

  5. Using the Bivariate Dale Model to jointly estimate predictors of frequency and quantity of alcohol use.

    Science.gov (United States)

    McMillan, Garnett P; Hanson, Tim; Bedrick, Edward J; Lapham, Sandra C

    2005-09-01

    This study demonstrates the usefulness of the Bivariate Dale Model (BDM) as a method for estimating the relationship between risk factors and the quantity and frequency of alcohol use, as well as the degree of association between these highly correlated drinking measures. The BDM is used to evaluate childhood sexual abuse, along with age and gender, as risk factors for the quantity and frequency of beer consumption in a sample of driving-while-intoxicated (DWI) offenders (N = 1,964; 1,612 men). The BDM allows one to estimate the relative odds of drinking up to each level of ordinal-scaled quantity and frequency of alcohol use, as well as model the degree of association between quantity and frequency of alcohol consumption as a function of covariates. Individuals who experienced childhood sexual abuse have increased risks of higher quantity and frequency of beer consumption. History of childhood sexual abuse has a greater effect on women, causing them to drink higher quantities of beer per drinking occasion. The BDM is a useful method for evaluating predictors of the quantity-frequency of alcohol consumption. SAS macrocode for fitting the BDM model is provided.

  6. Detection of recurrent chromosome abnormalities in Ewing's sarcoma and peripheral neuroectodermal tumor cells using bivariate flow karyotyping

    NARCIS (Netherlands)

    Boschman, G. A.; Rens, W.; Manders, E. M.; Slater, R. M.; Versteeg, R.; Aten, J. A.

    1992-01-01

    Bivariate flow karyotyping can be used for the detection of recurrent chromosome abnormalities in tumor cells. For this purpose 2 cell lines originally derived from Ewing's sarcomas and 4 cell lines from peripheral neuroectodermal tumors were used. The characteristic t(11;22) was known to be present

  7. Descriptive statistics.

    Science.gov (United States)

    Shi, Runhua; McLarty, Jerry W

    2009-10-01

    In this article, we introduced basic concepts of statistics, type of distributions, and descriptive statistics. A few examples were also provided. The basic concepts presented herein are only a fraction of the concepts related to descriptive statistics. Also, there are many commonly used distributions not presented herein, such as Poisson distributions for rare events and exponential distributions, F distributions, and logistic distributions. More information can be found in many statistics books and publications.

  8. Analysis of input variables of an artificial neural network using bivariate correlation and canonical correlation

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Valter Magalhaes; Pereira, Iraci Martinez, E-mail: valter.costa@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The monitoring of variables and diagnosis of sensor fault in nuclear power plants or processes industries is very important because a previous diagnosis allows the correction of the fault and, like this, to prevent the production stopped, improving operator's security and it's not provoking economics losses. The objective of this work is to build a set, using bivariate correlation and canonical correlation, which will be the set of input variables of an artificial neural network to monitor the greater number of variables. This methodology was applied to the IEA-R1 Research Reactor at IPEN. Initially, for the input set of neural network we selected the variables: nuclear power, primary circuit flow rate, control/safety rod position and difference in pressure in the core of the reactor, because almost whole of monitoring variables have relation with the variables early described or its effect can be result of the interaction of two or more. The nuclear power is related to the increasing and decreasing of temperatures as well as the amount radiation due fission of the uranium; the rods are controls of power and influence in the amount of radiation and increasing and decreasing of temperatures; the primary circuit flow rate has the function of energy transport by removing the nucleus heat. An artificial neural network was trained and the results were satisfactory since the IEA-R1 Data Acquisition System reactor monitors 64 variables and, with a set of 9 input variables resulting from the correlation analysis, it was possible to monitor 51 variables. (author)

  9. Assessing protein conformational sampling methods based on bivariate lag-distributions of backbone angles

    KAUST Repository

    Maadooliat, Mehdi

    2012-08-27

    Despite considerable progress in the past decades, protein structure prediction remains one of the major unsolved problems in computational biology. Angular-sampling-based methods have been extensively studied recently due to their ability to capture the continuous conformational space of protein structures. The literature has focused on using a variety of parametric models of the sequential dependencies between angle pairs along the protein chains. In this article, we present a thorough review of angular-sampling-based methods by assessing three main questions: What is the best distribution type to model the protein angles? What is a reasonable number of components in a mixture model that should be considered to accurately parameterize the joint distribution of the angles? and What is the order of the local sequence-structure dependency that should be considered by a prediction method? We assess the model fits for different methods using bivariate lag-distributions of the dihedral/planar angles. Moreover, the main information across the lags can be extracted using a technique called Lag singular value decomposition (LagSVD), which considers the joint distribution of the dihedral/planar angles over different lags using a nonparametric approach and monitors the behavior of the lag-distribution of the angles using singular value decomposition. As a result, we developed graphical tools and numerical measurements to compare and evaluate the performance of different model fits. Furthermore, we developed a web-tool (http://www.stat.tamu. edu/~madoliat/LagSVD) that can be used to produce informative animations. © The Author 2012. Published by Oxford University Press.

  10. A double SIMEX approach for bivariate random-effects meta-analysis of diagnostic accuracy studies

    Directory of Open Access Journals (Sweden)

    Annamaria Guolo

    2017-01-01

    Full Text Available Abstract Background Bivariate random-effects models represent a widely accepted and recommended approach for meta-analysis of test accuracy studies. Standard likelihood methods routinely used for inference are prone to several drawbacks. Small sample size can give rise to unreliable inferential conclusions and convergence issues make the approach unappealing. This paper suggests a different methodology to address such difficulties. Methods A SIMEX methodology is proposed. The method is a simulation-based technique originally developed as a correction strategy within the measurement error literature. It suits the meta-analysis framework as the diagnostic accuracy measures provided by each study are prone to measurement error. SIMEX can be straightforwardly adapted to cover different measurement error structures and to deal with covariates. The effortless implementation with standard software is an interesting feature of the method. Results Extensive simulation studies highlight the improvement provided by SIMEX over likelihood approach in terms of empirical coverage probabilities of confidence intervals under different scenarios, independently of the sample size and the values of the correlation between sensitivity and specificity. A remarkable amelioration is obtained in case of deviations from the normality assumption for the random-effects distribution. From a computational point of view, the application of SIMEX is shown to be neither involved nor subject to the convergence issues affecting likelihood-based alternatives. Application of the method to a diagnostic review of the performance of transesophageal echocardiography for assessing ascending aorta atherosclerosis enables overcoming limitations of the likelihood procedure. Conclusions The SIMEX methodology represents an interesting alternative to likelihood-based procedures for inference in meta-analysis of diagnostic accuracy studies. The approach can provide more accurate inferential

  11. Using bivariate signal analysis to characterize the epileptic focus: The benefit of surrogates

    Science.gov (United States)

    Andrzejak, R. G.; Chicharro, D.; Lehnertz, K.; Mormann, F.

    2011-04-01

    The disease epilepsy is related to hypersynchronous activity of networks of neurons. While acute epileptic seizures are the most extreme manifestation of this hypersynchronous activity, an elevated level of interdependence of neuronal dynamics is thought to persist also during the seizure-free interval. In multichannel recordings from brain areas involved in the epileptic process, this interdependence can be reflected in an increased linear cross correlation but also in signal properties of higher order. Bivariate time series analysis comprises a variety of approaches, each with different degrees of sensitivity and specificity for interdependencies reflected in lower- or higher-order properties of pairs of simultaneously recorded signals. Here we investigate which approach is best suited to detect putatively elevated interdependence levels in signals recorded from brain areas involved in the epileptic process. For this purpose, we use the linear cross correlation that is sensitive to lower-order signatures of interdependence, a nonlinear interdependence measure that integrates both lower- and higher-order properties, and a surrogate-corrected nonlinear interdependence measure that aims to specifically characterize higher-order properties. We analyze intracranial electroencephalographic recordings of the seizure-free interval from 29 patients with an epileptic focus located in the medial temporal lobe. Our results show that all three approaches detect higher levels of interdependence for signals recorded from the brain hemisphere containing the epileptic focus as compared to signals recorded from the opposite hemisphere. For the linear cross correlation, however, these differences are not significant. For the nonlinear interdependence measure, results are significant but only of moderate accuracy with regard to the discriminative power for the focal and nonfocal hemispheres. The highest significance and accuracy is obtained for the surrogate-corrected nonlinear

  12. New Colors for Histology: Optimized Bivariate Color Maps Increase Perceptual Contrast in Histological Images

    Science.gov (United States)

    Kather, Jakob Nikolas; Weis, Cleo-Aron; Marx, Alexander; Schuster, Alexander K.; Schad, Lothar R.; Zöllner, Frank Gerrit

    2015-01-01

    Background Accurate evaluation of immunostained histological images is required for reproducible research in many different areas and forms the basis of many clinical decisions. The quality and efficiency of histopathological evaluation is limited by the information content of a histological image, which is primarily encoded as perceivable contrast differences between objects in the image. However, the colors of chromogen and counterstain used for histological samples are not always optimally distinguishable, even under optimal conditions. Methods and Results In this study, we present a method to extract the bivariate color map inherent in a given histological image and to retrospectively optimize this color map. We use a novel, unsupervised approach based on color deconvolution and principal component analysis to show that the commonly used blue and brown color hues in Hematoxylin—3,3’-Diaminobenzidine (DAB) images are poorly suited for human observers. We then demonstrate that it is possible to construct improved color maps according to objective criteria and that these color maps can be used to digitally re-stain histological images. Validation To validate whether this procedure improves distinguishability of objects and background in histological images, we re-stain phantom images and N = 596 large histological images of immunostained samples of human solid tumors. We show that perceptual contrast is improved by a factor of 2.56 in phantom images and up to a factor of 2.17 in sets of histological tumor images. Context Thus, we provide an objective and reliable approach to measure object distinguishability in a given histological image and to maximize visual information available to a human observer. This method could easily be incorporated in digital pathology image viewing systems to improve accuracy and efficiency in research and diagnostics. PMID:26717571

  13. New Colors for Histology: Optimized Bivariate Color Maps Increase Perceptual Contrast in Histological Images.

    Directory of Open Access Journals (Sweden)

    Jakob Nikolas Kather

    Full Text Available Accurate evaluation of immunostained histological images is required for reproducible research in many different areas and forms the basis of many clinical decisions. The quality and efficiency of histopathological evaluation is limited by the information content of a histological image, which is primarily encoded as perceivable contrast differences between objects in the image. However, the colors of chromogen and counterstain used for histological samples are not always optimally distinguishable, even under optimal conditions.In this study, we present a method to extract the bivariate color map inherent in a given histological image and to retrospectively optimize this color map. We use a novel, unsupervised approach based on color deconvolution and principal component analysis to show that the commonly used blue and brown color hues in Hematoxylin-3,3'-Diaminobenzidine (DAB images are poorly suited for human observers. We then demonstrate that it is possible to construct improved color maps according to objective criteria and that these color maps can be used to digitally re-stain histological images.To validate whether this procedure improves distinguishability of objects and background in histological images, we re-stain phantom images and N = 596 large histological images of immunostained samples of human solid tumors. We show that perceptual contrast is improved by a factor of 2.56 in phantom images and up to a factor of 2.17 in sets of histological tumor images.Thus, we provide an objective and reliable approach to measure object distinguishability in a given histological image and to maximize visual information available to a human observer. This method could easily be incorporated in digital pathology image viewing systems to improve accuracy and efficiency in research and diagnostics.

  14. Negative-parity intruder states of the neutron-rich N=20, Z=14-16 isotones: a 1{Dirac_h}{omega} shell model description

    Energy Technology Data Exchange (ETDEWEB)

    Bouhelal, M. [Universite de Strasbourg, IPHC, CNRS/IN2P3, Strasbourg (France); Universite de Batna, Departement de Physique, Faculte des Sciences, Batna (Algeria); Haas, F.; Caurier, E.; Nowacki, F. [Universite de Strasbourg, IPHC, CNRS/IN2P3, Strasbourg (France); Bouldjedri, A. [Universite de Batna, Departement de Physique, Faculte des Sciences, Batna (Algeria)

    2009-12-15

    In order to get a consistent shell model description of the negative-parity states throughout the sd shell a new interaction (PSDPFB) has been developed. It was derived in the full p-sd-pf model space and is built on existing interactions for the major shells with adjustments of the cross-shell monopoles. The calculated energy spectra for these 1{Dirac_h}{omega} intruder states are compared to experiment for the N=20 neutron-rich isotones {sup 34}Si, {sup 35}P and {sup 36}S. A systematics for the multiplet configuration {nu}(d{sub 3/2}{sup -1}f{sub 7/2}{sup 1}) in even-even isotones from {sup 34}Si to {sup 40}Ca is also presented. (orig.)

  15. An application of UV-derivative spectrophotometry and bivariate calibration algorithm for study of photostability of levomepromazine hydrochloride.

    Science.gov (United States)

    Karpińska, Joanna; Sokół, Aneta; Skoczylas, Marta

    2008-12-15

    Derivative spectrophotometry and bivariate calibration algorithm were used for study of run of photooxidation of levomepromazine hydrochloride (LV). The actual concentrations of LV and its main degradation product levomepromazine sulphoxide (LV-SO) were calculated using data provided by applied methods. The direct reading of absorbance values at 302 nm and 334 nm were employed for quantification of LV and LV-SO, respectively, in the case of bivariate method. The derivative spectrophotometric method is based on transformation of zero-order spectra into first derivative. The values of first derivative at 334 nm were used for quantification of LV while at 278 nm for assay of LV-SO. The obtained quantitative data were applied for investigation of kinetics of photodegradation of LV.

  16. Statistical physics

    CERN Document Server

    Sadovskii, Michael V

    2012-01-01

    This volume provides a compact presentation of modern statistical physics at an advanced level. Beginning with questions on the foundations of statistical mechanics all important aspects of statistical physics are included, such as applications to ideal gases, the theory of quantum liquids and superconductivity and the modern theory of critical phenomena. Beyond that attention is given to new approaches, such as quantum field theory methods and non-equilibrium problems.

  17. An improved method for bivariate meta-analysis when within-study correlations are unknown.

    Science.gov (United States)

    Hong, Chuan; D Riley, Richard; Chen, Yong

    2017-10-21

    Multivariate meta-analysis, which jointly analyzes multiple and possibly correlated outcomes in a single analysis, is becoming increasingly popular in recent years. An attractive feature of the multivariate meta-analysis is its ability to account for the dependence between multiple estimates from the same study. However, standard inference procedures for multivariate meta-analysis require the knowledge of within-study correlations, which are usually unavailable. This limits standard inference approaches in practice. Riley et al proposed a working model and an overall synthesis correlation parameter to account for the marginal correlation between outcomes, where the only data needed are those required for a separate univariate random-effects meta-analysis. As within-study correlations are not required, the Riley method is applicable to a wide variety of evidence synthesis situations. However, the standard variance estimator of the Riley method is not entirely correct under many important settings. As a consequence, the coverage of a function of pooled estimates may not reach the nominal level even when the number of studies in the multivariate meta-analysis is large. In this paper, we improve the Riley method by proposing a robust variance estimator, which is asymptotically correct even when the model is misspecified (ie, when the likelihood function is incorrect). Simulation studies of a bivariate meta-analysis, in a variety of settings, show a function of pooled estimates has improved performance when using the proposed robust variance estimator. In terms of individual pooled estimates themselves, the standard variance estimator and robust variance estimator give similar results to the original method, with appropriate coverage. The proposed robust variance estimator performs well when the number of studies is relatively large. Therefore, we recommend the use of the robust method for meta-analyses with a relatively large number of studies (eg, m≥50). When the

  18. Bivariate least squares linear regression: Towards a unified analytic formalism. I. Functional models

    Science.gov (United States)

    Caimmi, R.

    2011-08-01

    Concerning bivariate least squares linear regression, the classical approach pursued for functional models in earlier attempts ( York, 1966, 1969) is reviewed using a new formalism in terms of deviation (matrix) traces which, for unweighted data, reduce to usual quantities leaving aside an unessential (but dimensional) multiplicative factor. Within the framework of classical error models, the dependent variable relates to the independent variable according to the usual additive model. The classes of linear models considered are regression lines in the general case of correlated errors in X and in Y for weighted data, and in the opposite limiting situations of (i) uncorrelated errors in X and in Y, and (ii) completely correlated errors in X and in Y. The special case of (C) generalized orthogonal regression is considered in detail together with well known subcases, namely: (Y) errors in X negligible (ideally null) with respect to errors in Y; (X) errors in Y negligible (ideally null) with respect to errors in X; (O) genuine orthogonal regression; (R) reduced major-axis regression. In the limit of unweighted data, the results determined for functional models are compared with their counterparts related to extreme structural models i.e. the instrumental scatter is negligible (ideally null) with respect to the intrinsic scatter ( Isobe et al., 1990; Feigelson and Babu, 1992). While regression line slope and intercept estimators for functional and structural models necessarily coincide, the contrary holds for related variance estimators even if the residuals obey a Gaussian distribution, with the exception of Y models. An example of astronomical application is considered, concerning the [O/H]-[Fe/H] empirical relations deduced from five samples related to different stars and/or different methods of oxygen abundance determination. For selected samples and assigned methods, different regression models yield consistent results within the errors (∓ σ) for both

  19. Harmonic statistics

    Energy Technology Data Exchange (ETDEWEB)

    Eliazar, Iddo, E-mail: eliazar@post.tau.ac.il

    2017-05-15

    The exponential, the normal, and the Poisson statistical laws are of major importance due to their universality. Harmonic statistics are as universal as the three aforementioned laws, but yet they fall short in their ‘public relations’ for the following reason: the full scope of harmonic statistics cannot be described in terms of a statistical law. In this paper we describe harmonic statistics, in their full scope, via an object termed harmonic Poisson process: a Poisson process, over the positive half-line, with a harmonic intensity. The paper reviews the harmonic Poisson process, investigates its properties, and presents the connections of this object to an assortment of topics: uniform statistics, scale invariance, random multiplicative perturbations, Pareto and inverse-Pareto statistics, exponential growth and exponential decay, power-law renormalization, convergence and domains of attraction, the Langevin equation, diffusions, Benford’s law, and 1/f noise. - Highlights: • Harmonic statistics are described and reviewed in detail. • Connections to various statistical laws are established. • Connections to perturbation, renormalization and dynamics are established.

  20. Statistical distributions

    CERN Document Server

    Forbes, Catherine; Hastings, Nicholas; Peacock, Brian J.

    2010-01-01

    A new edition of the trusted guide on commonly used statistical distributions Fully updated to reflect the latest developments on the topic, Statistical Distributions, Fourth Edition continues to serve as an authoritative guide on the application of statistical methods to research across various disciplines. The book provides a concise presentation of popular statistical distributions along with the necessary knowledge for their successful use in data modeling and analysis. Following a basic introduction, forty popular distributions are outlined in individual chapters that are complete with re

  1. Statistical methods

    CERN Document Server

    Szulc, Stefan

    1965-01-01

    Statistical Methods provides a discussion of the principles of the organization and technique of research, with emphasis on its application to the problems in social statistics. This book discusses branch statistics, which aims to develop practical ways of collecting and processing numerical data and to adapt general statistical methods to the objectives in a given field.Organized into five parts encompassing 22 chapters, this book begins with an overview of how to organize the collection of such information on individual units, primarily as accomplished by government agencies. This text then

  2. Statistical optics

    CERN Document Server

    Goodman, Joseph W

    2015-01-01

    This book discusses statistical methods that are useful for treating problems in modern optics, and the application of these methods to solving a variety of such problems This book covers a variety of statistical problems in optics, including both theory and applications.  The text covers the necessary background in statistics, statistical properties of light waves of various types, the theory of partial coherence and its applications, imaging with partially coherent light, atmospheric degradations of images, and noise limitations in the detection of light. New topics have been introduced i

  3. Saliva buatan meningkatkan kekuatan tekan semen ionomer kaca tipe II yang direndam dalam minuman isotonik (Artificial saliva increases the compressive strength of glass ionomer cement type II soaked in isotonic drinks)

    OpenAIRE

    Juliatri Juliatri; D.H.C. Pangemanan; Dwi Cahya Fitriyana

    2014-01-01

    Immersion of glass ionomer cement (GIC) type II in acid drink like isotonic drink could reduce its compressive strength. This is due to the matrix degradation process of GIC in acid condition. However, there is artificial saliva that can neutralize this condition. The purpose of this study was to evaluate the effect of artificial saliva on compressive strength of glass ionomer cement type II immersed in isotonic drink. The GICspecimens of 6 x 6 x 12 mm 3 beam were immersed for ...

  4. On the sources of the height–intelligence correlation: New insights from a bivariate ACE model with assortative mating

    OpenAIRE

    Beauchamp, Jonathan P; Cesarini, David; Johannesson, Magnus; Lindqvist, Erik; Apicella, Coren Lee

    2010-01-01

    A robust positive correlation between height and intelligence, as measured by IQ tests, has been established in the literature. This paper makes several contributions toward establishing the causes of this association. First, we extend the standard bivariate ACE model to account for assortative mating. The more general theoretical framework provides several key insights, including formulas to decompose a cross-trait genetic correlation into components attributable to assortative mating and pl...

  5. Bivariate Extension of the Quadrature Method of Moments for Modeling Simultaneous Coagulation and Sintering of Particle Populations.

    Science.gov (United States)

    Wright, Douglas L.; McGraw, Robert; Rosner, Daniel E.

    2001-04-15

    We extendthe application of moment methods to multivariate suspended particle population problems-those for which size alone is insufficient to specify the state of a particle in the population. Specifically, a bivariate extension of the quadrature method of moments (QMOM) (R. McGraw, Aerosol Sci. Technol. 27, 255 (1997)) is presented for efficiently modeling the dynamics of a population of inorganic nanoparticles undergoing simultaneous coagulation and particle sintering. Continuum regime calculations are presented for the Koch-Friedlander-Tandon-Rosner model, which includes coagulation by Brownian diffusion (evaluated for particle fractal dimensions, D(f), in the range 1.8-3) and simultaneous sintering of the resulting aggregates (P. Tandon and D. E. Rosner, J. Colloid Interface Sci. 213, 273 (1999)). For evaluation purposes, and to demonstrate the computational efficiency of the bivariate QMOM, benchmark calculations are carried out using a high-resolution discrete method to evolve the particle distribution function n(nu, a) for short to intermediate times (where nu and a are particle volume and surface area, respectively). Time evolution of a selected set of 36 low-order mixed moments is obtained by integration of the full bivariate distribution and compared with the corresponding moments obtained directly using two different extensions of the QMOM. With the more extensive treatment, errors of less than 1% are obtained over substantial aerosol evolution, while requiring only a few minutes (rather than days) of CPU time. Longer time QMOM simulations lend support to the earlier finding of a self-preserving limit for the dimensionless joint (nu, a) particle distribution function under simultaneous coagulation and sintering (Tandon and Rosner, 1999; D. E. Rosner and S. Yu, AIChE J., 47 (2001)). We demonstrate that, even in the bivariate case, it is possible to use the QMOM to rapidly model the approach to asymptotic behavior, allowing an immediate assessment of

  6. Powerful bivariate genome-wide association analyses suggest the SOX6 gene influencing both obesity and osteoporosis phenotypes in males.

    Science.gov (United States)

    Liu, Yao-Zhong; Pei, Yu-Fang; Liu, Jian-Feng; Yang, Fang; Guo, Yan; Zhang, Lei; Liu, Xiao-Gang; Yan, Han; Wang, Liang; Zhang, Yin-Ping; Levy, Shawn; Recker, Robert R; Deng, Hong-Wen

    2009-08-28

    Current genome-wide association studies (GWAS) are normally implemented in a univariate framework and analyze different phenotypes in isolation. This univariate approach ignores the potential genetic correlation between important disease traits. Hence this approach is difficult to detect pleiotropic genes, which may exist for obesity and osteoporosis, two common diseases of major public health importance that are closely correlated genetically. To identify such pleiotropic genes and the key mechanistic links between the two diseases, we here performed the first bivariate GWAS of obesity and osteoporosis. We searched for genes underlying co-variation of the obesity phenotype, body mass index (BMI), with the osteoporosis risk phenotype, hip bone mineral density (BMD), scanning approximately 380,000 SNPs in 1,000 unrelated homogeneous Caucasians, including 499 males and 501 females. We identified in the male subjects two SNPs in intron 1 of the SOX6 (SRY-box 6) gene, rs297325 and rs4756846, which were bivariately associated with both BMI and hip BMD, achieving p values of 6.82x10(-7) and 1.47x10(-6), respectively. The two SNPs ranked at the top in significance for bivariate association with BMI and hip BMD in the male subjects among all the approximately 380,000 SNPs examined genome-wide. The two SNPs were replicated in a Framingham Heart Study (FHS) cohort containing 3,355 Caucasians (1,370 males and 1,985 females) from 975 families. In the FHS male subjects, the two SNPs achieved p values of 0.03 and 0.02, respectively, for bivariate association with BMI and femoral neck BMD. Interestingly, SOX6 was previously found to be essential to both cartilage formation/chondrogenesis and obesity-related insulin resistance, suggesting the gene's dual role in both bone and fat. Our findings, together with the prior biological evidence, suggest the SOX6 gene's importance in co-regulation of obesity and osteoporosis.

  7. A power study of bivariate LOD score analysis of a complex trait and fear/discomfort with strangers.

    Science.gov (United States)

    Ji, Fei; Lee, Dayoung; Mendell, Nancy Role

    2005-12-30

    Complex diseases are often reported along with disease-related traits (DRT). Sometimes investigators consider both disease and DRT phenotypes separately and sometimes they consider individuals as affected if they have either the disease or the DRT, or both. We propose instead to consider the joint distribution of the disease and the DRT and do a linkage analysis assuming a pleiotropic model. We evaluated our results through analysis of the simulated datasets provided by Genetic Analysis Workshop 14. We first conducted univariate linkage analysis of the simulated disease, Kofendrerd Personality Disorder and one of its simulated associated traits, phenotype b (fear/discomfort with strangers). Subsequently, we considered the bivariate phenotype, which combined the information on Kofendrerd Personality Disorder and fear/discomfort with strangers. We developed a program to perform bivariate linkage analysis using an extension to the Elston-Stewart peeling method of likelihood calculation. Using this program we considered the microsatellites within 30 cM of the gene pleiotropic for this simulated disease and DRT. Based on 100 simulations of 300 families we observed excellent power to detect linkage within 10 cM of the disease locus using the DRT and the bivariate trait.

  8. Comparing Johnson’s SBB, Weibull and Logit-Logistic bivariate distributions for modeling tree diameters and heights using copulas

    Directory of Open Access Journals (Sweden)

    Jose Javier Gorgoso-Varela

    2016-04-01

    Full Text Available Aim of study: In this study we compare the accuracy of three bivariate distributions: Johnson’s SBB, Weibull-2P and LL-2P functions for characterizing the joint distribution of tree diameters and heights.Area of study: North-West of Spain.Material and methods: Diameter and height measurements of 128 plots of pure and even-aged Tasmanian blue gum (Eucalyptus globulus Labill. stands located in the North-west of Spain were considered in the present study. The SBB bivariate distribution was obtained from SB marginal distributions using a Normal Copula based on a four-parameter logistic transformation. The Plackett Copula was used to obtain the bivariate models from the Weibull and Logit-logistic univariate marginal distributions. The negative logarithm of the maximum likelihood function was used to compare the results and the Wilcoxon signed-rank test was used to compare the related samples of these logarithms calculated for each sample plot and each distribution.Main results: The best results were obtained by using the Plackett copula and the best marginal distribution was the Logit-logistic.Research highlights: The copulas used in this study have shown a good performance for modeling the joint distribution of tree diameters and heights. They could be easily extended for modelling multivariate distributions involving other tree variables, such as tree volume or biomass.

  9. Comparing Johnson’s SBB, Weibull and Logit-Logistic bivariate distributions for modeling tree diameters and heights using copulas

    Energy Technology Data Exchange (ETDEWEB)

    Cardil Forradellas, A.; Molina Terrén, D.M.; Oliveres, J.; Castellnou, M.

    2016-07-01

    Aim of study: In this study we compare the accuracy of three bivariate distributions: Johnson’s SBB, Weibull-2P and LL-2P functions for characterizing the joint distribution of tree diameters and heights. Area of study: North-West of Spain. Material and methods: Diameter and height measurements of 128 plots of pure and even-aged Tasmanian blue gum (Eucalyptus globulus Labill.) stands located in the North-west of Spain were considered in the present study. The SBB bivariate distribution was obtained from SB marginal distributions using a Normal Copula based on a four-parameter logistic transformation. The Plackett Copula was used to obtain the bivariate models from the Weibull and Logit-logistic univariate marginal distributions. The negative logarithm of the maximum likelihood function was used to compare the results and the Wilcoxon signed-rank test was used to compare the related samples of these logarithms calculated for each sample plot and each distribution. Main results: The best results were obtained by using the Plackett copula and the best marginal distribution was the Logit-logistic. Research highlights: The copulas used in this study have shown a good performance for modeling the joint distribution of tree diameters and heights. They could be easily extended for modelling multivariate distributions involving other tree variables, such as tree volume or biomass. (Author)

  10. Isokinetic strength and endurance during 30-day 6 degrees head-down bed rest with isotonic and isokinetic exercise training

    Science.gov (United States)

    Greenleaf, J. E.; Bernauer, E. M.; Ertl, A. C.; Bulbulian, R.; Bond, M.

    1994-01-01

    The purpose of our study was to determine if an intensive, intermittent, isokinetic, lower extremity exercise training program would attenuate or eliminate the decrease of muscular strength and endurance during prolonged bed rest (BR). The 19 male subjects (36 +/- 1 yr, 178 +/- 2 cm, 76.5 +/- 1.7 kg) were allocated into a no exercise (NOE) training group (N = 5), an isotonic (lower extremity cycle ergometer) exercise (ITE) training group (N = 7), and an isokinetic (isokinetic knee flexion-extension) exercise (IKE) training group (N = 7). Peak knee (flexion and extension) and shoulder (abduction-adduction) functions were measured weekly in all groups with one 5-repetition set. After BR, average knee extension total work decreased by 16% with NOE, increased by 27% with IKE, and was unchanged with ITE. Average knee flexion total work and peak torque (strength) responses were unchanged in all groups. Force production increased by 20% with IKE and was unchanged with NOE and ITE. Shoulder total work was unchanged in all groups, while gross average peak torque increased by 27% with ITE and by 22% with IKE, and was unchanged with NOE. Thus, while ITE training can maintain some isokinetic functions during BR, maximal intermittent IKE training can increase other functions above pre-BR control levels.

  11. Isokinetic Strength and Endurance During 30-day 6 deg Head-Down Bed Rest with Isotonic and Isokinetic Exercise Training

    Science.gov (United States)

    Greenleaf, J. E.; Bernauer, E. M.; Ertl, A. C.; Bond, M.; Bulbulian, R.

    1994-01-01

    The purpose of our study was to determine if an intensive, intermittent, isokinetic, lower extremity exercise training program would attenuate or eliminate the decrease of muscular strength and endurance during prolonged bed rest (BR). The 19 male subjects (36 +/- 1 yr, 178 +/- 2 cm, 76.5 +/- 1.7 kg) were allocated into a no exercise (NOE) training group (N = 5), an isotonic (lower extremity cycle orgometer) exercise (ITE) training group (N = 7), and an isokinetic (isokinetic knee flexion-extension) exercise (IKE) training group (N = 7). Peak knee (flexion and extension) and shoulder (abduction-adduction) functions were measured weekly in all groups with one 5-repetition set. After BR, average knee extension total work decreased by 16% with NOE, increased by 27% with IKE, and was unchanged with ITE. Average knee flexion total work and peak torque (strength) responses were unchanged in all groups. Force production increased by 20% with IKE and was unchanged with NOE and ITE. Shoulder total work was unchanged in all groups, while gross average peak torque increased by 27% with ITE and by 22% with IKE, and was unchanged with NOE. Thus, while ITE training can maintain some isokinetic functions during BR, maximal intermittent IKE training can increase other functions above pre-BR control levels.

  12. Handgrip and general muscular strength and endurance during prolonged bedrest with isometric and isotonic leg exercise training

    Science.gov (United States)

    Greenleaf, J. E.; Starr, J. C.; Van Beaumont, W.; Convertino, V. A.

    1983-01-01

    Measurements of maximal grip strength and endurance at 40 percent max strength were obtained for 7 men 19-21 years of age, 1-2 days before and on the first recovery day during three 2-week bedrest (BR) periods, each separated by a 3-week ambulatory recovery period. The subjects performed isometric exercise (IME) for 1 hr/day, isotonic exercise (ITE) for 1 hr/day, and no exercise (NOE) in the three BR periods. It was found that the mean maximal grip strength was unchanged after all three BR periods. Mean grip endurance was found to be unchanged after IME and ITE training, but was significantly reduced after NOE. These results indicate that IME and ITE training during BR do not increase or decrease maximal grip strength, alghough they prevent loss of grip endurance, while the maximal strength of all other major muscle groups decreases in proportion to the length of BR to 70 days. The maximal strength reduction of the large muscle groups was found to be about twice that of the small muscle groups during BR. In addition, it is shown that changes in maximal strength after spaceflight, BR, or water immersion deconditioning cannot be predicted from changes in submaximal or maximal oxygen uptake values.

  13. Differential effects of isotonic and hypotonic 4% albumin solution on intracranial pressure and renal perfusion and function.

    Science.gov (United States)

    Iguchi, Naoya; Kosaka, Junko; Bertolini, Joseph; May, Clive N; Lankadeva, Yugeesh R; Bellomo, Rinaldo

    2018-03-01

    Albumin is used to resuscitate trauma patients but may increase intracranial pressure (ICP). Its effects on renal blood flow and function are unknown. Our aim was to examine the effects of hypertonic albumin on ICP and renal function, and if any effects are due to the hypotonicity of the solution containing albumin or to albumin itself. Cross-over, randomised controlled experimental study of six adult Merino ewes in the animal facility of a research institute. Sheep were implanted with flow probes around the pulmonary and renal arteries and an ICP monitoring catheter in a lateral cerebral ventricle. Conscious sheep received normal saline, commercially available hypotonic 4% albumin solution (4% Albumex [278 mOsm/kg]) or a novel isotonic 4% albumin solution (288 mOsm/kg), with at least 48 hours between each intervention. Commercial hypotonic albumin solution increased ICP (by 8.5 mmHg [SEM, 2.1 mmHg]; P hypotonic albumin solution was associated with an increase in central venous pressure (CVP) (by 5.4 mmHg [SEM, 0.6 mmHg]; P hypotonic albumin solution increased ICP and CVP, but did not alter arterial pressure, cardiac output renal blood flow or renal function. Our findings support the view that the tonicity of the albumin solution, rather than the albumin itself, is responsible for increasing ICP.

  14. Scan Statistics

    CERN Document Server

    Glaz, Joseph

    2009-01-01

    Suitable for graduate students and researchers in applied probability and statistics, as well as for scientists in biology, computer science, pharmaceutical science and medicine, this title brings together a collection of chapters illustrating the depth and diversity of theory, methods and applications in the area of scan statistics.

  15. Practical Statistics

    CERN Document Server

    Lyons, L.

    2016-01-01

    Accelerators and detectors are expensive, both in terms of money and human effort. It is thus important to invest effort in performing a good statistical anal- ysis of the data, in order to extract the best information from it. This series of five lectures deals with practical aspects of statistical issues that arise in typical High Energy Physics analyses.

  16. Bivariate random-effects meta-analysis and the estimation of between-study correlation

    Directory of Open Access Journals (Sweden)

    Lambert Paul C

    2007-01-01

    Full Text Available Abstract Background When multiple endpoints are of interest in evidence synthesis, a multivariate meta-analysis can jointly synthesise those endpoints and utilise their correlation. A multivariate random-effects meta-analysis must incorporate and estimate the between-study correlation (ρB. Methods In this paper we assess maximum likelihood estimation of a general normal model and a generalised model for bivariate random-effects meta-analysis (BRMA. We consider two applied examples, one involving a diagnostic marker and the other a surrogate outcome. These motivate a simulation study where estimation properties from BRMA are compared with those from two separate univariate random-effects meta-analyses (URMAs, the traditional approach. Results The normal BRMA model estimates ρB as -1 in both applied examples. Analytically we show this is due to the maximum likelihood estimator sensibly truncating the between-study covariance matrix on the boundary of its parameter space. Our simulations reveal this commonly occurs when the number of studies is small or the within-study variation is relatively large; it also causes upwardly biased between-study variance estimates, which are inflated to compensate for the restriction on ρ^ MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaaiiGacuWFbpGCgaqcaaaa@2E83@B. Importantly, this does not induce any systematic bias in the pooled estimates and produces conservative standard errors and mean-square errors. Furthermore, the normal BRMA is preferable to two normal URMAs; the mean-square error and standard error of pooled estimates is generally smaller in the BRMA, especially given data missing at random. For meta-analysis of proportions we then show that a generalised BRMA model is better still. This correctly uses a binomial

  17. Semiconductor statistics

    CERN Document Server

    Blakemore, J S

    1962-01-01

    Semiconductor Statistics presents statistics aimed at complementing existing books on the relationships between carrier densities and transport effects. The book is divided into two parts. Part I provides introductory material on the electron theory of solids, and then discusses carrier statistics for semiconductors in thermal equilibrium. Of course a solid cannot be in true thermodynamic equilibrium if any electrical current is passed; but when currents are reasonably small the distribution function is but little perturbed, and the carrier distribution for such a """"quasi-equilibrium"""" co

  18. Statistics Clinic

    Science.gov (United States)

    Feiveson, Alan H.; Foy, Millennia; Ploutz-Snyder, Robert; Fiedler, James

    2014-01-01

    Do you have elevated p-values? Is the data analysis process getting you down? Do you experience anxiety when you need to respond to criticism of statistical methods in your manuscript? You may be suffering from Insufficient Statistical Support Syndrome (ISSS). For symptomatic relief of ISSS, come for a free consultation with JSC biostatisticians at our help desk during the poster sessions at the HRP Investigators Workshop. Get answers to common questions about sample size, missing data, multiple testing, when to trust the results of your analyses and more. Side effects may include sudden loss of statistics anxiety, improved interpretation of your data, and increased confidence in your results.

  19. On the matched pairs sign test using bivariate ranked set sampling ...

    African Journals Online (AJOL)

    Administrator

    2008-01-15

    Jan 15, 2008 ... control confounding in the design stage of a study, matching is a strategy that must include elements of both design and analysis”. (Hennekens and Buring 1987). For example, a two-year .... used the RSS sampling method to improve parametric and non- parametric statistical inference. For non-parametric ...

  20. CMS Statistics

    Data.gov (United States)

    U.S. Department of Health & Human Services — The CMS Center for Strategic Planning produces an annual CMS Statistics reference booklet that provides a quick reference for summary information about health...

  1. WPRDC Statistics

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Data about the usage of the WPRDC site and its various datasets, obtained by combining Google Analytics statistics with information from the WPRDC's data portal.

  2. Accident Statistics

    Data.gov (United States)

    Department of Homeland Security — Accident statistics available on the Coast Guard’s website by state, year, and one variable to obtain tables and/or graphs. Data from reports has been loaded for...

  3. Image Statistics

    Energy Technology Data Exchange (ETDEWEB)

    Wendelberger, Laura Jean [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-08

    In large datasets, it is time consuming or even impossible to pick out interesting images. Our proposed solution is to find statistics to quantify the information in each image and use those to identify and pick out images of interest.

  4. Multiparametric statistics

    CERN Document Server

    Serdobolskii, Vadim Ivanovich

    2007-01-01

    This monograph presents mathematical theory of statistical models described by the essentially large number of unknown parameters, comparable with sample size but can also be much larger. In this meaning, the proposed theory can be called "essentially multiparametric". It is developed on the basis of the Kolmogorov asymptotic approach in which sample size increases along with the number of unknown parameters.This theory opens a way for solution of central problems of multivariate statistics, which up until now have not been solved. Traditional statistical methods based on the idea of an infinite sampling often break down in the solution of real problems, and, dependent on data, can be inefficient, unstable and even not applicable. In this situation, practical statisticians are forced to use various heuristic methods in the hope the will find a satisfactory solution.Mathematical theory developed in this book presents a regular technique for implementing new, more efficient versions of statistical procedures. ...

  5. Trichomoniasis Statistics

    Science.gov (United States)

    ... Search Form Controls Cancel Submit Search the CDC Trichomoniasis Note: Javascript is disabled or is not supported ... Twitter STD on Facebook Sexually Transmitted Diseases (STDs) Trichomoniasis Statistics Recommend on Facebook Tweet Share Compartir In ...

  6. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... in different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved...

  7. Vital statistics

    CERN Document Server

    MacKenzie, Dana

    2004-01-01

    The drawbacks of using 19th-century mathematics in physics and astronomy are illustrated. To continue with the expansion of the knowledge about the cosmos, the scientists will have to come in terms with modern statistics. Some researchers have deliberately started importing techniques that are used in medical research. However, the physicists need to identify the brand of statistics that will be suitable for them, and make a choice between the Bayesian and the frequentists approach. (Edited abstract).

  8. Knee-Joint Proprioception During 30-Day 6 deg Head-Down Bed Rest with Isotonic and Isokinetic Exercise Training

    Science.gov (United States)

    Bernauer, E. M.; Walby, W. F.; Ertl, A. C.; Dempster, P. T.; Bond, M.; Greenleaf, J. E.

    1994-01-01

    To determine if daily isotonic exercise or isokinetic exercise training coupled with daily log proprioceptive training, would influence log proprioceptive tracking responses during Bed Rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a NO-Exercise (NOE) training control group (n = 5), and IsoTanic Exercise (ITE, n = 7) and IsoKinetic Exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min period / d, 5 d /week. Only the IKE group performed proprioceptive training using a now isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pro-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p less than 0.05) at the end of BR in both exercise groups when compared with NOE responses (extension: NOE 80.7 +/- 0.7%, ITE 82.9 +/- 0.6%, IKE 86.5* +/- 0.7%; flexion: NOE 77.6 +/- 1.50, ITE 80.0 +/- 0.8% (NS), IKE 83.6* +/- 0.8%). Although proprioceptive tracking was unchanged during BR with NOE, both lsotonic exercise training (without additional propriaceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.

  9. Alterations in Skeletal Muscle Function with Microgravity, and the Protective Effects of High Resistance Isometric and Isotonic Exercise

    Science.gov (United States)

    Fitts, R. H.; Hurst, J. E.; Norenberg, K. M.; Widrick, J. J.; Riley, D. A.; Bain, J. L. W.; Trappe, S. W.; Trappe, T. A.; Costill, D. L.

    1999-01-01

    Exposure to microgravity or models designed to mimic the unloaded condition, such as bed rest in humans and hindlimb unloading (HU) in rats leads to skeletal muscle atrophy, a loss in peak force and power, and an increased susceptibility to fatigue. The posterior compartment muscles of the lower leg (calf muscle group) appear to be particularly susceptible. Following only 1 wk in space or HU, rat soleus muscle showed a 30 to 40% loss in wet weight. After 3 wk of HU, almost all of the atrophied soleus fibers showed a significant increase in maximal shortening velocity (V(sub 0)), while only 25 to 30 % actually transitioned to fast fibers. The increased V(sub 0), was protective in that it reduced the decline in peak power associated with the reduced peak force. When the soleus is stimulated in situ following HU or zero-g one observes an increased rate and extent of fatigue, and in the former the increased fatigue is associated with a more rapid depletion of muscle glycogen and lactate production. Our working hypothesis is that following HU or spaceflight in rats and bed rest or spaceflight in humans limb skeletal muscles during contractile activity depend more on carbohydrates and less on fatty acids for their substrate supply. Baldwin et al. found 9 days of spaceflight to reduce by 37% the ability of both the high and low oxidative regions of the vastus muscle to oxidize long-chain fatty acids. This decline was not associated with any change in the enzymes of the tricarboxylic acid cycle or oxidation pathway. The purpose of the current research was to establish the extent of functional change in the slow type I and fast type H fibers of the human calf muscle following 17 days of spaceflight, and determine the cellular mechanisms of the observed changes. A second goal was to study the effectiveness of high resistance isotonic and isometric exercise in preventing the deleterious functional changes associated with unloading.

  10. Thiamine-deficient encephalopathy due to excessive intake of isotonic drink or overstrict diet therapy in Japanese children.

    Science.gov (United States)

    Saeki, Keisuke; Saito, Yoshiaki; Komaki, Hirofumi; Sakakibra, Takafumi; Nakagawa, Eiji; Sugai, Kenji; Sakuma, Hiroshi; Sasaki, Masayuki; Honda, Takashi; Hayashi, Hatsuka; Katori, Naho; Miyahara, Yoko

    2010-08-01

    To report on two children with encephalopathy caused by dietary thiamine deficiency due to newly developing nutritional problems in contemporary Japan. A 1-year-old boy who had consumed 1l of isotonic drinks per day for 4 months after an episode of diarrhea, and presented with ocular movement disorder, dystonia, and unconsciousness. The other subject was an 11-month-old boy who suffered from vomiting and somnolence; he and his mother had atopic dermatitis, and he had been on a low-allergen diet that strictly restricted intake of eggs, dairy products, meat, and fish since his early infancy. Both patients showed decreased blood thiamine levels and magnetic resonance imaging revealed striatal and thalamic lesions. Thiamine administration yielded prompt improvement of symptoms, but cavitiform lesions in the bilateral putamen persisted in the first patient, accompanied by residual generalized dystonia. Marked elevation of blood/cerebrospinal lactate levels and severe hyponatremia were present in this patient. Thiamine-deficient encephalopathy in Japanese children due to excessive intake of sports drink or overstrict diet therapy for atopic dermatitis has been increasingly reported during the last decade, but is still not broadly recognized. These children may visit hospitals due to persistent vomiting as a symptom of thiamine deficiency, but glucose infusion without thiamine supplementation can aggravate their condition. Knowledge of these facts in medical and public settings is necessary to correct the erroneous impression that nutritional options given to ill children are necessarily beneficial for health, and promote awareness that they can be harmful when consumed in excess. Copyright 2009 Elsevier B.V. All rights reserved.

  11. Statistical mechanics

    CERN Document Server

    Jana, Madhusudan

    2015-01-01

    Statistical mechanics is self sufficient, written in a lucid manner, keeping in mind the exam system of the universities. Need of study this subject and its relation to Thermodynamics is discussed in detail. Starting from Liouville theorem gradually, the Statistical Mechanics is developed thoroughly. All three types of Statistical distribution functions are derived separately with their periphery of applications and limitations. Non-interacting ideal Bose gas and Fermi gas are discussed thoroughly. Properties of Liquid He-II and the corresponding models have been depicted. White dwarfs and condensed matter physics, transport phenomenon - thermal and electrical conductivity, Hall effect, Magneto resistance, viscosity, diffusion, etc. are discussed. Basic understanding of Ising model is given to explain the phase transition. The book ends with a detailed coverage to the method of ensembles (namely Microcanonical, canonical and grand canonical) and their applications. Various numerical and conceptual problems ar...

  12. Statistical physics

    CERN Document Server

    Guénault, Tony

    2007-01-01

    In this revised and enlarged second edition of an established text Tony Guénault provides a clear and refreshingly readable introduction to statistical physics, an essential component of any first degree in physics. The treatment itself is self-contained and concentrates on an understanding of the physical ideas, without requiring a high level of mathematical sophistication. A straightforward quantum approach to statistical averaging is adopted from the outset (easier, the author believes, than the classical approach). The initial part of the book is geared towards explaining the equilibrium properties of a simple isolated assembly of particles. Thus, several important topics, for example an ideal spin-½ solid, can be discussed at an early stage. The treatment of gases gives full coverage to Maxwell-Boltzmann, Fermi-Dirac and Bose-Einstein statistics. Towards the end of the book the student is introduced to a wider viewpoint and new chapters are included on chemical thermodynamics, interactions in, for exam...

  13. Statistical mechanics

    CERN Document Server

    Schwabl, Franz

    2006-01-01

    The completely revised new edition of the classical book on Statistical Mechanics covers the basic concepts of equilibrium and non-equilibrium statistical physics. In addition to a deductive approach to equilibrium statistics and thermodynamics based on a single hypothesis - the form of the microcanonical density matrix - this book treats the most important elements of non-equilibrium phenomena. Intermediate calculations are presented in complete detail. Problems at the end of each chapter help students to consolidate their understanding of the material. Beyond the fundamentals, this text demonstrates the breadth of the field and its great variety of applications. Modern areas such as renormalization group theory, percolation, stochastic equations of motion and their applications to critical dynamics, kinetic theories, as well as fundamental considerations of irreversibility, are discussed. The text will be useful for advanced students of physics and other natural sciences; a basic knowledge of quantum mechan...

  14. Survival advantage associated with treatment of injury at designated trauma centers: a bivariate probit model with instrumental variables.

    Science.gov (United States)

    Pracht, Etienne E; Tepas, Joseph J; Celso, Brian G; Langland-Orban, Barbara; Flint, Lewis

    2007-02-01

    This article analyzes the effectiveness of designated trauma centers in Florida concerning reduction in the mortality risk of severely injured trauma victims. A bivariate probit model is used to compute the differential impact of two alternative acute care treatment sites. The alternative sites are defined as (1) a nontrauma center (NC) or (2) a designated trauma center (DTC). An instrumental-variables method was used to adjust for prehospital selection bias in addition to the influence of age, gender, race, risk of mortality, and type of injury. Treatment at a DTC was associated with a reduction of 0.13 in the probability of mortality.

  15. Powerful bivariate genome-wide association analyses suggest the SOX6 gene influencing both obesity and osteoporosis phenotypes in males.

    Directory of Open Access Journals (Sweden)

    Yao-Zhong Liu

    2009-08-01

    Full Text Available Current genome-wide association studies (GWAS are normally implemented in a univariate framework and analyze different phenotypes in isolation. This univariate approach ignores the potential genetic correlation between important disease traits. Hence this approach is difficult to detect pleiotropic genes, which may exist for obesity and osteoporosis, two common diseases of major public health importance that are closely correlated genetically.To identify such pleiotropic genes and the key mechanistic links between the two diseases, we here performed the first bivariate GWAS of obesity and osteoporosis. We searched for genes underlying co-variation of the obesity phenotype, body mass index (BMI, with the osteoporosis risk phenotype, hip bone mineral density (BMD, scanning approximately 380,000 SNPs in 1,000 unrelated homogeneous Caucasians, including 499 males and 501 females. We identified in the male subjects two SNPs in intron 1 of the SOX6 (SRY-box 6 gene, rs297325 and rs4756846, which were bivariately associated with both BMI and hip BMD, achieving p values of 6.82x10(-7 and 1.47x10(-6, respectively. The two SNPs ranked at the top in significance for bivariate association with BMI and hip BMD in the male subjects among all the approximately 380,000 SNPs examined genome-wide. The two SNPs were replicated in a Framingham Heart Study (FHS cohort containing 3,355 Caucasians (1,370 males and 1,985 females from 975 families. In the FHS male subjects, the two SNPs achieved p values of 0.03 and 0.02, respectively, for bivariate association with BMI and femoral neck BMD. Interestingly, SOX6 was previously found to be essential to both cartilage formation/chondrogenesis and obesity-related insulin resistance, suggesting the gene's dual role in both bone and fat.Our findings, together with the prior biological evidence, suggest the SOX6 gene's importance in co-regulation of obesity and osteoporosis.

  16. Statistical mechanics

    CERN Document Server

    Davidson, Norman

    2003-01-01

    Clear and readable, this fine text assists students in achieving a grasp of the techniques and limitations of statistical mechanics. The treatment follows a logical progression from elementary to advanced theories, with careful attention to detail and mathematical development, and is sufficiently rigorous for introductory or intermediate graduate courses.Beginning with a study of the statistical mechanics of ideal gases and other systems of non-interacting particles, the text develops the theory in detail and applies it to the study of chemical equilibrium and the calculation of the thermody

  17. AP statistics

    CERN Document Server

    Levine-Wissing, Robin

    2012-01-01

    All Access for the AP® Statistics Exam Book + Web + Mobile Everything you need to prepare for the Advanced Placement® exam, in a study system built around you! There are many different ways to prepare for an Advanced Placement® exam. What's best for you depends on how much time you have to study and how comfortable you are with the subject matter. To score your highest, you need a system that can be customized to fit you: your schedule, your learning style, and your current level of knowledge. This book, and the online tools that come with it, will help you personalize your AP® Statistics prep

  18. Statistical inference

    CERN Document Server

    Rohatgi, Vijay K

    2003-01-01

    Unified treatment of probability and statistics examines and analyzes the relationship between the two fields, exploring inferential issues. Numerous problems, examples, and diagrams--some with solutions--plus clear-cut, highlighted summaries of results. Advanced undergraduate to graduate level. Contents: 1. Introduction. 2. Probability Model. 3. Probability Distributions. 4. Introduction to Statistical Inference. 5. More on Mathematical Expectation. 6. Some Discrete Models. 7. Some Continuous Models. 8. Functions of Random Variables and Random Vectors. 9. Large-Sample Theory. 10. General Meth

  19. Effectiveness of enforcement levels of speed limit and drink driving laws and associated factors – Exploratory empirical analysis using a bivariate ordered probit model

    National Research Council Canada - National Science Library

    Behram Wali; Anwaar Ahmed; Shahid Iqbal; Arshad Hussain

    2017-01-01

    ... levels of speed limit and drink driving laws. The effectiveness of enforcement levels of speed limit and drink driving laws has been investigated through development of bivariate ordered probit model using data extricated from WHO's global...

  20. Effectiveness of enforcement levels of speed limit and drink driving laws and associated factors -Exploratory empirical analysis using a bivariate ordered probit model

    National Research Council Canada - National Science Library

    Behram Wali Anwaar Ahmed Shahid Iqbal Arshad Hussain

    2017-01-01

    ... levels of speed limit and drink driving laws. The effectiveness of enforcement levels of speed limit and drink driving laws has been investigated through development of bivariate ordered probit model using data extricated from...

  1. Statistics and analysis of scientific data

    CERN Document Server

    Bonamente, Massimiliano

    2017-01-01

    The revised second edition of this textbook provides the reader with a solid foundation in probability theory and statistics as applied to the physical sciences, engineering and related fields. It covers a broad range of numerical and analytical methods that are essential for the correct analysis of scientific data, including probability theory, distribution functions of statistics, fits to two-dimensional data and parameter estimation, Monte Carlo methods and Markov chains. Features new to this edition include: • a discussion of statistical techniques employed in business science, such as multiple regression analysis of multivariate datasets. • a new chapter on the various measures of the mean including logarithmic averages. • new chapters on systematic errors and intrinsic scatter, and on the fitting of data with bivariate errors. • a new case study and additional worked examples. • mathematical derivations and theoretical background material have been appropriately marked,to improve the readabili...

  2. Statistical Mechancis

    CERN Document Server

    Gallavotti, Giovanni

    2011-01-01

    C. Cercignani: A sketch of the theory of the Boltzmann equation.- O.E. Lanford: Qualitative and statistical theory of dissipative systems.- E.H. Lieb: many particle Coulomb systems.- B. Tirozzi: Report on renormalization group.- A. Wehrl: Basic properties of entropy in quantum mechanics.

  3. Statistical Computing

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 10. Statistical Computing - Understanding Randomness and Random Numbers. Sudhakar Kunte. Series Article Volume 4 Issue 10 October 1999 pp 16-21. Fulltext. Click here to view fulltext PDF. Permanent link:

  4. A novel isotonic-balanced electrolyte solution with 1% glucose for intraoperative fluid therapy in children: results of a prospective multicentre observational post-authorization safety study (PASS).

    Science.gov (United States)

    Sümpelmann, Robert; Mader, Thomas; Eich, Christoph; Witt, Lars; Osthaus, Wilhelm A

    2010-11-01

    The recommendations for intraoperative fluid therapy in children have been adapted from hypotonic to isotonic electrolyte solutions with lower glucose concentrations (1-2.5% instead of 5%) to avoid hyponatremia and hyperglycemia. The objective of this prospective multicentre observational post-authorization safety study was to evaluate the intraoperative use of a novel isotonic-balanced electrolyte solution with 1% glucose (BS-G1) with a particular focus on changes in acid-base status, electrolyte and glucose concentrations. Following local ethics committee approval, pediatric patients aged up to 4 years with an ASA risk score of I-III undergoing intraoperative administration of BS-G1 were enrolled. Patient demographics, the performed procedure, adverse drug reactions, hemodynamic data, and the results of blood gas analysis before and after infusion were documented with a focus on changes in acid-base status, electrolyte and glucose concentrations. In 107 patients (ASA I-III; age 16.2 ± 15.4, range day of birth to 47.7 months; body weight 8.8 ± 4.8, range 1.6-18.8 kg), the mean volume infused was 20 ± 12.6 (range 3.6-83.3) ml·kg(-1) BS-G1. During the infusion, hemoglobin, hematocrit, anion gap, strong ion difference, and calcium decreased and chloride and glucose increased significantly within the physiologic range. All other measured parameters including sodium, bicarbonate, base excess, and lactate remained stable. Neither hypoglycemia (glucose 10 mmol·l(-1) ) was documented after BS-G1 infusion. No adverse drug reactions were reported. The studied isotonic-balanced electrolyte solution with 1% glucose helps to avoid perioperative acid-base imbalance, hyponatremia, hyperglycemia, and ketoacidosis in infants and toddlers and may therefore enhance patient safety. © 2010 Blackwell Publishing Ltd.

  5. The relationship between arginine vasopressin levels and hyponatremia following a percutaneous renal biopsy in children receiving hypotonic or isotonic intravenous fluids.

    Science.gov (United States)

    Kanda, Kyoko; Nozu, Kandai; Kaito, Hiroshi; Iijima, Kazumoto; Nakanishi, Koichi; Yoshikawa, Norishige; Ninchoji, Takeshi; Hashimura, Yuya; Matsuo, Masafumi; Moritz, Michael L

    2011-01-01

    Post-operative hyponatremia is a common complication in children which results from hypotonic fluid administration in the presence of arginine vasopressin (AVP) excess. We evaluated the relationship between the change in serum sodium and AVP levels following percutaneous renal biopsy in children receiving either hypotonic or isotonic fluids. This study was prompted after we encountered a patient who developed near-fatal hyponatremic encephalopathy following a renal biopsy while receiving hypotonic fluids. The relationship between the change in serum sodium and AVP levels was evaluated prior to (T0) and at 5 h (T5) following a percutaneous renal biopsy in 60 children receiving either hypotonic (0.6% NaCl, 90 mEq/L) or isotonic fluids (0.9% NaCl, 154 mEq/L). The proportion of patients with elevated AVP levels post-procedure was similar between those receiving 0.6 or 0.9% NaCl (30 vs. 26%). Patients receiving 0.6% NaCl with elevated AVP levels experienced a fall in serum sodium of 1.9 ± 1.5 mEq/L, whereas those receiving 0.9% NaCl had a rise in serum sodium of 0.85 ± 0.34 mEq/L with no patients developing hyponatremia. There were no significant changes in serum sodium levels in patients with normal AVP concentrations post-procedure in either group. In conclusion, elevated AVP levels were common among our patients following a percutaneous renal biopsy. Isotonic fluids prevented a fall in serum sodium and hyponatremia, while hypotonic fluids did not.

  6. Operator identities involving the bivariate Rogers-Szegö polynomials and their applications to the multiple q-series identities

    Science.gov (United States)

    Zhang, Zhizheng; Wang, Tianze

    2008-07-01

    In this paper, we first give several operator identities involving the bivariate Rogers-Szegö polynomials. By applying the technique of parameter augmentation to the multiple q-binomial theorems given by Milne [S.C. Milne, Balanced summation theorems for U(n) basic hypergeometric series, AdvE Math. 131 (1997) 93-187], we obtain several new multiple q-series identities involving the bivariate Rogers-Szegö polynomials. These include multiple extensions of Mehler's formula and Rogers's formula. Our U(n+1) generalizations are quite natural as they are also a direct and immediate consequence of their (often classical) known one-variable cases and Milne's fundamental theorem for An or U(n+1) basic hypergeometric series in Theorem 1E49 of [S.C. Milne, An elementary proof of the Macdonald identities for , Adv. Math. 57 (1985) 34-70], as rewritten in Lemma 7.3 on p. 163 of [S.C. Milne, Balanced summation theorems for U(n) basic hypergeometric series, Adv. Math. 131 (1997) 93-187] or Corollary 4.4 on pp. 768-769 of [S.C. Milne, M. Schlosser, A new An extension of Ramanujan's summation with applications to multilateral An series, Rocky Mountain J. Math. 32 (2002) 759-792].

  7. [Descriptive statistics].

    Science.gov (United States)

    Rendón-Macías, Mario Enrique; Villasís-Keever, Miguel Ángel; Miranda-Novales, María Guadalupe

    2016-01-01

    Descriptive statistics is the branch of statistics that gives recommendations on how to summarize clearly and simply research data in tables, figures, charts, or graphs. Before performing a descriptive analysis it is paramount to summarize its goal or goals, and to identify the measurement scales of the different variables recorded in the study. Tables or charts aim to provide timely information on the results of an investigation. The graphs show trends and can be histograms, pie charts, "box and whiskers" plots, line graphs, or scatter plots. Images serve as examples to reinforce concepts or facts. The choice of a chart, graph, or image must be based on the study objectives. Usually it is not recommended to use more than seven in an article, also depending on its length.

  8. Nonparametric association analysis of bivariate left-truncated competing risks data.

    Science.gov (United States)

    Cheng, Yu; Shen, Pao-Sheng; Zhang, Zhumin; Lai, HuiChuan J

    2016-05-01

    We develop time-varying association analyses for onset ages of two lung infections to address the statistical challenges in utilizing registry data where onset ages are left-truncated by ages of entry and competing-risk censored by deaths. Two types of association estimators are proposed based on conditional cause-specific hazard function and cumulative incidence function that are adapted from unconditional quantities to handle left truncation. Asymptotic properties of the estimators are established by using the empirical process techniques. Our simulation study shows that the estimators perform well with moderate sample sizes. We apply our methods to the Cystic Fibrosis Foundation Registry data to study the relationship between onset ages of Pseudomonas aeruginosa and Staphylococcus aureus infections. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Experimental statistics

    CERN Document Server

    Natrella, Mary Gibbons

    1963-01-01

    Formulated to assist scientists and engineers engaged in army ordnance research and development programs, this well-known and highly regarded handbook is a ready reference for advanced undergraduate and graduate students as well as for professionals seeking engineering information and quantitative data for designing, developing, constructing, and testing equipment. Topics include characterizing and comparing the measured performance of a material, product, or process; general considerations in planning experiments; statistical techniques for analyzing extreme-value data; use of transformations

  10. Spatial prediction of flood susceptible areas using rule based decision tree (DT) and a novel ensemble bivariate and multivariate statistical models in GIS

    Science.gov (United States)

    Tehrany, Mahyat Shafapour; Pradhan, Biswajeet; Jebur, Mustafa Neamah

    2013-11-01

    Decision tree (DT) machine learning algorithm was used to map the flood susceptible areas in Kelantan, Malaysia.We used an ensemble frequency ratio (FR) and logistic regression (LR) model in order to overcome weak points of the LR.Combined method of FR and LR was used to map the susceptible areas in Kelantan, Malaysia.Results of both methods were compared and their efficiency was assessed.Most influencing conditioning factors on flooding were recognized.

  11. Statistical mechanics

    CERN Document Server

    Sheffield, Scott

    2009-01-01

    In recent years, statistical mechanics has been increasingly recognized as a central domain of mathematics. Major developments include the Schramm-Loewner evolution, which describes two-dimensional phase transitions, random matrix theory, renormalization group theory and the fluctuations of random surfaces described by dimers. The lectures contained in this volume present an introduction to recent mathematical progress in these fields. They are designed for graduate students in mathematics with a strong background in analysis and probability. This book will be of particular interest to graduate students and researchers interested in modern aspects of probability, conformal field theory, percolation, random matrices and stochastic differential equations.

  12. Full Volume Isotonic (0.9%) vs. Two-Thirds Volume Hypotonic (0.18%) Intravenous Maintenance Fluids in Preventing Hyponatremia in Children Admitted to Pediatric Intensive Care Unit-A Randomized Controlled Study.

    Science.gov (United States)

    S K, Raksha; Dakshayani, B; R, Premalatha

    2017-03-02

    : We aimed to compare the effect of two different intravenous fluid regimes on the incidence of hyponatremia in children. : Children 1 month to 18 years of age, admitted to pediatric intensive care unit (PICU) of a tertiary care medical college hospital were randomized to receive either isotonic fluid (0.9% saline in 5% dextrose) at the standard maintenance rate or hypotonic fluid (0.18% saline in 5% dextrose) at two-thirds of the standard maintenance rate. : A total of 240 children were randomized (120 isotonic, 120 hypotonic). In all, 16.7% children in hypotonic group developed hyponatremia compared with 7.5% in isotonic group ( p  = 0.029). Duration of PICU stay was significantly more in Hypotonic group. : We conclude that use of 0.9% saline in 5% dextrose as maintenance fluid helps in reducing the incidence of hospital-acquired hyponatremia and duration of intensive care unit stay among children admitted to PICU.

  13. A Bivariate Mixed Distribution with a Heavy-tailed Component and its Application to Single-site Daily Rainfall Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chao ..; Singh, Vijay P.; Mishra, Ashok K.

    2013-02-06

    This paper presents an improved brivariate mixed distribution, which is capable of modeling the dependence of daily rainfall from two distinct sources (e.g., rainfall from two stations, two consecutive days, or two instruments such as satellite and rain gauge). The distribution couples an existing framework for building a bivariate mixed distribution, the theory of copulae and a hybrid marginal distribution. Contributions of the improved distribution are twofold. One is the appropriate selection of the bivariate dependence structure from a wider admissible choice (10 candidate copula families). The other is the introduction of a marginal distribution capable of better representing low to moderate values as well as extremes of daily rainfall. Among several applications of the improved distribution, particularly presented here is its utility for single-site daily rainfall simulation. Rather than simulating rainfall occurrences and amounts separately, the developed generator unifies the two processes by generalizing daily rainfall as a Markov process with autocorrelation described by the improved bivariate mixed distribution. The generator is first tested on a sample station in Texas. Results reveal that the simulated and observed sequences are in good agreement with respect to essential characteristics. Then, extensive simulation experiments are carried out to compare the developed generator with three other alternative models: the conventional two-state Markov chain generator, the transition probability matrix model and the semi-parametric Markov chain model with kernel density estimation for rainfall amounts. Analyses establish that overall the developed generator is capable of reproducing characteristics of historical extreme rainfall events and is apt at extrapolating rare values beyond the upper range of available observed data. Moreover, it automatically captures the persistence of rainfall amounts on consecutive wet days in a relatively natural and easy way

  14. The systematic study of the electroporation and electrofusion of B16-F1 and CHO cells in isotonic and hypotonic buffer.

    Science.gov (United States)

    Usaj, Marko; Kanduser, Masa

    2012-09-01

    The fusogenic state of the cell membrane can be induced by external electric field. When two fusogenic membranes are in close contact, cell fusion takes place. An appropriate hypotonic treatment of cells before the application of electric pulses significantly improves electrofusion efficiency. How hypotonic treatment improves electrofusion is still not known in detail. Our results indicate that at given induced transmembrane potential electroporation was not affected by buffer osmolarity. In contrast to electroporation, cells' response to hypotonic treatment significantly affects their electrofusion. High fusion yield was observed when B16-F1 cells were used; this cell line in hypotonic buffer resulted in 41 ± 9 % yield, while in isotonic buffer 32 ± 11 % yield was observed. Based on our knowledge, these fusion yields determined in situ by dual-color fluorescence microscopy are among the highest in electrofusion research field. The use of hypotonic buffer was more crucial for electrofusion of CHO cells; the fusion yield increased from below 1 % in isotonic buffer to 10 ± 4 % in hypotonic buffer. Since the same degree of cell permeabilization was achieved in both buffers, these results indicate that hypotonic treatment significantly improves fusion yield. The effect could be attributed to improved physical contact of cell membranes or to enhanced fusogenic state of the cell membrane itself.

  15. Choice of dialysis treatment and type of medical unit (private vs public): application of a recursive bivariate probit.

    Science.gov (United States)

    Gitto, Lara; Santoro, Domenico; Sobbrio, Giuseppe

    2006-11-01

    ESRD patients have to deal with two choices: the first is related to the dialysis modality; the second concerns the type of dialysis unit (public vs private) where to undertake the treatment. Such a choice is related to unobservable factors, among which there might be patients' clinical factors as well as factors related to the characteristics of each unit. We employ a recursive bivariate probit estimation on a sample of ESRD Sicilian patients in order to evaluate the impact of these factors. Results can have important implications for Sicily in order to organize dialysis services: here, in fact, the number of private centres is higher than in other Italian Regions. Copyright (c) 2006 John Wiley & Sons, Ltd.

  16. Local linear estimation of concordance probability with application to covariate effects models on association for bivariate failure-time data.

    Science.gov (United States)

    Ding, Aidong Adam; Hsieh, Jin-Jian; Wang, Weijing

    2015-01-01

    Bivariate survival analysis has wide applications. In the presence of covariates, most literature focuses on studying their effects on the marginal distributions. However covariates can also affect the association between the two variables. In this article we consider the latter issue by proposing a nonstandard local linear estimator for the concordance probability as a function of covariates. Under the Clayton copula, the conditional concordance probability has a simple one-to-one correspondence with the copula parameter for different data structures including those subject to independent or dependent censoring and dependent truncation. The proposed method can be used to study how covariates affect the Clayton association parameter without specifying marginal regression models. Asymptotic properties of the proposed estimators are derived and their finite-sample performances are examined via simulations. Finally, for illustration, we apply the proposed method to analyze a bone marrow transplant data set.

  17. Statistical Neurodynamics.

    Science.gov (United States)

    Paine, Gregory Harold

    1982-03-01

    The primary objective of the thesis is to explore the dynamical properties of small nerve networks by means of the methods of statistical mechanics. To this end, a general formalism is developed and applied to elementary groupings of model neurons which are driven by either constant (steady state) or nonconstant (nonsteady state) forces. Neuronal models described by a system of coupled, nonlinear, first-order, ordinary differential equations are considered. A linearized form of the neuronal equations is studied in detail. A Lagrange function corresponding to the linear neural network is constructed which, through a Legendre transformation, provides a constant of motion. By invoking the Maximum-Entropy Principle with the single integral of motion as a constraint, a probability distribution function for the network in a steady state can be obtained. The formalism is implemented for some simple networks driven by a constant force; accordingly, the analysis focuses on a study of fluctuations about the steady state. In particular, a network composed of N noninteracting neurons, termed Free Thinkers, is considered in detail, with a view to interpretation and numerical estimation of the Lagrange multiplier corresponding to the constant of motion. As an archetypical example of a net of interacting neurons, the classical neural oscillator, consisting of two mutually inhibitory neurons, is investigated. It is further shown that in the case of a network driven by a nonconstant force, the Maximum-Entropy Principle can be applied to determine a probability distribution functional describing the network in a nonsteady state. The above examples are reconsidered with nonconstant driving forces which produce small deviations from the steady state. Numerical studies are performed on simplified models of two physical systems: the starfish central nervous system and the mammalian olfactory bulb. Discussions are given as to how statistical neurodynamics can be used to gain a better

  18. Use of statistical tests and statistical software choice in 2014: tale from three Medline indexed Pakistani journals.

    Science.gov (United States)

    Shaikh, Masood Ali

    2016-04-01

    Statistical tests help infer meaningful conclusions from studies conducted and data collected. This descriptive study analyzed the type of statistical tests used and the statistical software utilized for analysis reported in the original articles published in 2014 by the three Medline-indexed journals of Pakistan. Cumulatively, 466 original articles were published in 2014. The most frequently reported statistical tests for original articles by all three journals were bivariate parametric and non-parametric tests i.e. involving comparisons between two groups e.g. Chi-square test, t-test, and various types of correlations. Cumulatively, 201 (43.1%) articles used these tests. SPSS was the primary choice for statistical analysis, as it was exclusively used in 374 (80.3%) original articles. There has been a substantial increase in the number of articles published, and in the sophistication of statistical tests used in the articles published in the Pakistani Medline indexed journals in 2014, compared to 2007.

  19. Hypotonic fluid reduce serum sodium compared to isotonic fluids during anesthesia induction in pediatric patients undergoing maxillofacial surgery-type of infusion affects blood electrolytes and glucose: an observational study.

    Science.gov (United States)

    Ouchi, Kentaro; Sugiyama, Kazuna

    2016-07-27

    Reportedly, administration of hypotonic fluids containing 30.8-74 mEq/L sodium with 5 % glucose may lead to serious hyponatremia or hyperglycemia. In Japan, hypotonic fluids containing 90 mEq/L sodium with 2.6 % glucose are commonly used. We compared blood electrolyte balance and blood glucose concentration with the use of isotonic (140 mEq/L sodium with 1 % glucose) versus hypotonic fluids in pediatric patients. We studied 77 children aged 5 months to 2 years who underwent oro-maxillofacial surgery and dental treatment under general anesthesia. Patients were categorized according to the fluids infused (hypotonic or isotonic). Blood samples were obtained from the dorsalis pedis artery between the conclusion of anesthesia induction and commencement of surgery. We compared blood sodium, potassium and glucose concentrations in the two fluid groups during the pre-anesthesia and post-anesthesia-induction periods. There were no significant differences in pre-anesthesia values between isotonic (n = 35) and hypotonic groups (n = 42). There were significant differences between isotonic and hypotonic groups in post-anesthesia-induction concentrations of sodium (isotonic, 138.7 ± 1.4 mEq/L; hypotonic, 137.5 ± 1.3 mEq/L; p = 0.0003) and glucose (isotonic, 88.0 ± 9.4 mg/dL; hypotonic, 109.9 ± 18.4 mg/dL; p hypotonic, 4.0 ± 0.2 mEq/L; p = 0.6615) between the two groups. Isotonic solution administration enables avoidance of serum sodium reduction and serum glucose elevation in infants, and may therefore enhance patient safety in comparison with hypotonic solutions. University Hospital Medical Information Network Clinical Trials Registry ( UMIN000014648 ), registration 25 July 2014.

  20. Ajuste de modelos de platô de resposta via regressão isotônica Response plateau models fitting via isotonic regression

    Directory of Open Access Journals (Sweden)

    Renata Pires Gonçalves

    2012-02-01

    . The experiments of type dosage x response are very common in the determination of levels of nutrients in optimal food balance and include the use of regression models to achieve this objective. Nevertheless, the regression analysis routine, generally, uses a priori information about a possible relationship between the response variable. The isotonic regression is a method of estimation by least squares that generates estimates which preserves data ordering. In the theory of isotonic regression this information is essential and it is expected to increase fitting efficiency. The objective of this work was to use an isotonic regression methodology, as an alternative way of analyzing data of Zn deposition in tibia of male birds of Hubbard lineage. We considered the models of plateau response of polynomial quadratic and linear exponential forms. In addition to these models, we also proposed the fitting of a logarithmic model to the data and the efficiency of the methodology was evaluated by Monte Carlo simulations, considering different scenarios for the parametric values. The isotonization of the data yielded an improvement in all the fitting quality parameters evaluated. Among the models used, the logarithmic presented estimates of the parameters more consistent with the values reported in literature.

  1. In children requiring intravenous fluid for hydration maintenance, which out of hypotonic saline and isotonic saline is less likely to result in the development of hyponatraemia?

    Science.gov (United States)

    Tran, Michael Ma; Tantsis, Esther M; Ging, Joanne M

    2017-03-01

    The administration of intravenous fluids remains a common intervention for hospitalised children. Commonly used hypotonic fluids administered at maintenance rates provide 2-4 mmol/kg/day of sodium. Being hypotonic, the development of hyponatraemia remains a risk. The consequences of hyponatraemia are not insignificant, with possibilities of irreversible neurological morbidity and mortality. There is currently no clear consensus on the optimal composition of fluids to be used for intravenous rehydration. A review of the available literature suggests that children who receive isotonic fluid have a lower risk of developing hyponatraemia, regardless of the rate of administration. This result is most applicable in the first 24 h of administration in a wide age group of paediatric patients with varying severities of illness. © 2017 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

  2. Shell-model calculations for the semi-magic nucleus 85Br and systematic features of the N = 50 odd-A isotones

    Science.gov (United States)

    Guo, Rui-Ju; Li, Zhi-Quan; Liu, Chen; Tian, Yong-He; Wang, Shou-Yu

    2017-08-01

    Level structures of 85Br have been investigated using the shell-model code nushellx within a large model space containing the neutron-core excitations across the N = 50 closed shell. The calculated results have been compared with the available experimental data. Reasonable agreement between the experimental and calculated values is obtained, which indicates that the neutron-core excitations are essential to reproduce the level structures of 85Br. The systematic features of neutron-core excitations in the N = 50 isotones are investigated. Supported by Natural Science Foundation of China (11622540, 11461141001, U1432119) and Computations were Carried Out on an HP Proliant DL785G6 Server Hosted by the Institute of Space Science of Shandong University

  3. Mapping the boundaries of the seniority regime and collective motion: Coulomb excitation studies of N = 122 isotones $^{206}$Po and $^{208}$Rn

    CERN Multimedia

    Butler, P; Voulot, D; Rahkila, P J; Darby, I G; Grahn, T; Bree, N C F; Julin, R J; Diriken, J V J; Jenkins, D G; Kroell, T; Huyse, M L

    In regions near magic nuclei, seniority can be regarded as a good quantum number. In the N = 122 isotones above the Z = 82 shell closure relative high-$\\textit{j}\\,$ single-particle proton orbitals dominate the structure and thus levels up to $\\textit{I}$ = 2$\\textit{j}$ - 1 could, in principle, be understood within the seniority scheme. While B(E2) values usually increase within the band with increasing $\\textit{I}$, the seniority scheme can lead to a contrasting result. The present proposal addresses this phenomenon through the measurements of previously unknown B(E2; 0$^{+}\\rightarrow$ 2$^{+}$) values in $^{206}$Po and $^{208}$Rn. The proposed Coulomb excitation measurements of radioactive beams will be carried out at the REX-ISOLDE facility using the MINIBALL $\\gamma$-ray spectrometer.

  4. Mechanisms Underlying Activation of α₁-Adrenergic Receptor-Induced Trafficking of AQP5 in Rat Parotid Acinar Cells under Isotonic or Hypotonic Conditions.

    Science.gov (United States)

    Bragiel, Aneta M; Wang, Di; Pieczonka, Tomasz D; Shono, Masayuki; Ishikawa, Yasuko

    2016-06-28

    Defective cellular trafficking of aquaporin-5 (AQP5) to the apical plasma membrane (APM) in salivary glands is associated with the loss of salivary fluid secretion. To examine mechanisms of α₁-adrenoceptor (AR)-induced trafficking of AQP5, immunoconfocal microscopy and Western blot analysis were used to analyze AQP5 localization in parotid tissues stimulated with phenylephrine under different osmolality. Phenylephrine-induced trafficking of AQP5 to the APM and lateral plasma membrane (LPM) was mediated via the α1A-AR subtype, but not the α1B- and α1D-AR subtypes. Phenylephrine-induced trafficking of AQP5 was inhibited by ODQ and KT5823, inhibitors of nitric oxide (NO)-stimulated guanylcyclase (GC) and protein kinase (PK) G, respectively, indicating the involvement of the NO/ soluble (c) GC/PKG signaling pathway. Under isotonic conditions, phenylephrine-induced trafficking was inhibited by La(3+), implying the participation of store-operated Ca(2+) channel. Under hypotonic conditions, phenylephrine-induced trafficking of AQP5 to the APM was higher than that under isotonic conditions. Under non-stimulated conditions, hypotonicity-induced trafficking of AQP5 to the APM was inhibited by ruthenium red and La(3+), suggesting the involvement of extracellular Ca(2+) entry. Thus, α1A-AR activation induced the trafficking of AQP5 to the APM and LPM via the Ca(2+)/ cyclic guanosine monophosphate (cGMP)/PKG signaling pathway, which is associated with store-operated Ca(2+) entry.

  5. Mechanisms Underlying Activation of α1-Adrenergic Receptor-Induced Trafficking of AQP5 in Rat Parotid Acinar Cells under Isotonic or Hypotonic Conditions

    Science.gov (United States)

    Bragiel, Aneta M.; Wang, Di; Pieczonka, Tomasz D.; Shono, Masayuki; Ishikawa, Yasuko

    2016-01-01

    Defective cellular trafficking of aquaporin-5 (AQP5) to the apical plasma membrane (APM) in salivary glands is associated with the loss of salivary fluid secretion. To examine mechanisms of α1-adrenoceptor (AR)-induced trafficking of AQP5, immunoconfocal microscopy and Western blot analysis were used to analyze AQP5 localization in parotid tissues stimulated with phenylephrine under different osmolality. Phenylephrine-induced trafficking of AQP5 to the APM and lateral plasma membrane (LPM) was mediated via the α1A-AR subtype, but not the α1B- and α1D-AR subtypes. Phenylephrine-induced trafficking of AQP5 was inhibited by ODQ and KT5823, inhibitors of nitric oxide (NO)-stimulated guanylcyclase (GC) and protein kinase (PK) G, respectively, indicating the involvement of the NO/ soluble (c) GC/PKG signaling pathway. Under isotonic conditions, phenylephrine-induced trafficking was inhibited by La3+, implying the participation of store-operated Ca2+ channel. Under hypotonic conditions, phenylephrine-induced trafficking of AQP5 to the APM was higher than that under isotonic conditions. Under non-stimulated conditions, hypotonicity-induced trafficking of AQP5 to the APM was inhibited by ruthenium red and La3+, suggesting the involvement of extracellular Ca2+ entry. Thus, α1A-AR activation induced the trafficking of AQP5 to the APM and LPM via the Ca2+/ cyclic guanosine monophosphate (cGMP)/PKG signaling pathway, which is associated with store-operated Ca2+ entry. PMID:27367668

  6. On the sources of the height-intelligence correlation: new insights from a bivariate ACE model with assortative mating.

    Science.gov (United States)

    Beauchamp, Jonathan P; Cesarini, David; Johannesson, Magnus; Lindqvist, Erik; Apicella, Coren

    2011-03-01

    A robust positive correlation between height and intelligence, as measured by IQ tests, has been established in the literature. This paper makes several contributions toward establishing the causes of this association. First, we extend the standard bivariate ACE model to account for assortative mating. The more general theoretical framework provides several key insights, including formulas to decompose a cross-trait genetic correlation into components attributable to assortative mating and pleiotropy and to decompose a cross-trait within-family correlation. Second, we use a large dataset of male twins drawn from Swedish conscription records and examine how well genetic and environmental factors explain the association between (i) height and intelligence and (ii) height and military aptitude, a professional psychologist's assessment of a conscript's ability to deal with wartime stress. For both traits, we find suggestive evidence of a shared genetic architecture with height, but we demonstrate that point estimates are very sensitive to assumed degrees of assortative mating. Third, we report a significant within-family correlation between height and intelligence (p^ = 0.10), suggesting that pleiotropy might be at play.

  7. Genetic relationship of discrete-time survival with fertility and production in dairy cattle using bivariate models

    Directory of Open Access Journals (Sweden)

    Alenda Rafael

    2007-07-01

    Full Text Available Abstract Bivariate analyses of functional longevity in dairy cattle measured as survival to next lactation (SURV with milk yield and fertility traits were carried out. A sequential threshold-linear censored model was implemented for the analyses of SURV. Records on 96 642 lactations from 41 170 cows were used to estimate genetic parameters, using animal models, for longevity, 305 d-standardized milk production (MY305, days open (DO and number of inseminations to conception (INS in the Spanish Holstein population; 31% and 30% of lactations were censored for DO and INS, respectively. Heritability estimates for SURV and MY305 were 0.11 and 0.27 respectively; while heritability estimates for fertility traits were lower (0.07 for DO and 0.03 for INS. Antagonist genetic correlations were estimated between SURV and fertility (-0.78 and -0.54 for DO and INS, respectively or production (-0.53 for MY305, suggesting reduced functional longevity with impaired fertility and increased milk production. Longer days open seems to affect survival more than increased INS. Also, high productive cows were more problematic, less functional and more liable to being culled. The results suggest that the sequential threshold model is a method that might be considered at evaluating genetic relationship between discrete-time survival and other traits, due to its flexibility.

  8. Assessing characteristics related to the use of seatbelts and cell phones by drivers: application of a bivariate probit model.

    Science.gov (United States)

    Russo, Brendan J; Kay, Jonathan J; Savolainen, Peter T; Gates, Timothy J

    2014-06-01

    The effects of cell phone use and safety belt use have been an important focus of research related to driver safety. Cell phone use has been shown to be a significant source of driver distraction contributing to substantial degradations in driver performance, while safety belts have been demonstrated to play a vital role in mitigating injuries to crash-involved occupants. This study examines the prevalence of cell phone use and safety belt non-use among the driving population through direct observation surveys. A bivariate probit model is developed to simultaneously examine the factors that affect cell phone and safety belt use among motor vehicle drivers. The results show that several factors may influence drivers' decision to use cell phones and safety belts, and that these decisions are correlated. Understanding the factors that affect both cell phone use and safety belt non-use is essential to targeting policy and programs that reduce such behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Bivariate ordered-response probit model of driver's and passenger's injury severities in collisions with fixed objects.

    Science.gov (United States)

    Yamamoto, Toshiyuki; Shankar, Venkataraman N

    2004-09-01

    A bivariate ordered-response probit model of driver's and most severely injured passenger's severity (IS) in collisions with fixed objects is developed in this study. Exact passenger's IS is not necessarily observed, especially when only most severe injury of the accident and driver's injury are recorded in the police reports. To accommodate passenger IS as well, we explicitly develop a partial observability model of passenger IS in multi-occupant vehicle (HOV). The model has consistent coefficients for the driver IS between single-occupant vehicle (SOV) and multiple-occupant vehicle accidents, and provides more efficient coefficient estimates by taking into account the common unobserved factors between driver and passenger IS. The results of the empirical analysis using 4-year statewide accident data in Washington State reveal the effects of driver's characteristics, vehicle attributes, types of objects, and environmental conditions on both driver and passenger IS, and that their IS have different elasticities to some of the risk factors. Copyright 2003 Elsevier Ltd.

  10. A comparison of the effect of 5-bromodeoxyuridine substitution on 33258 Hoechst- and DAPI-fluorescence of isolated chromosomes by bivariate flow karyotyping

    NARCIS (Netherlands)

    Buys, C. H.; Mesa, J.; van der Veen, A. Y.; Aten, J. A.

    1986-01-01

    Application of the fluorescent DNA-intercalator propidium iodide for stabilization of the mitotic chromosome structure during isolation of chromosomes from V79 Chinese hamster cells and subsequent staining with the fluorochromes 33258 Hoechst or DAPI allowed bivariate flow karyotyping of isolated

  11. Bivariate genome-wide association meta-analysis of pediatric musculoskeletal traits reveals pleiotropic effects at the SREBF1/TOM1L2 locus

    DEFF Research Database (Denmark)

    Medina-Gomez, Carolina; Kemp, John P; Dimou, Niki L

    2017-01-01

    Bone mineral density is known to be a heritable, polygenic trait whereas genetic variants contributing to lean mass variation remain largely unknown. We estimated the shared SNP heritability and performed a bivariate GWAS meta-analysis of total-body lean mass (TB-LM) and total-body less head bone...

  12. Aquaculture in artificially developed wetlands in urban areas: an application of the bivariate relationship between soil and surface water in landscape ecology.

    Science.gov (United States)

    Paul, Abhijit

    2011-01-01

    Wetlands show a strong bivariate relationship between soil and surface water. Artificially developed wetlands help to build landscape ecology and make built environments sustainable. The bheries, wetlands of eastern Calcutta (India), utilize the city sewage to develop urban aquaculture that supports the local fish industries and opens a new frontier in sustainable environmental planning research.

  13. Statistic complexity: combining kolmogorov complexity with an ensemble approach.

    Science.gov (United States)

    Emmert-Streib, Frank

    2010-08-26

    The evaluation of the complexity of an observed object is an old but outstanding problem. In this paper we are tying on this problem introducing a measure called statistic complexity. This complexity measure is different to all other measures in the following senses. First, it is a bivariate measure that compares two objects, corresponding to pattern generating processes, on the basis of the normalized compression distance with each other. Second, it provides the quantification of an error that could have been encountered by comparing samples of finite size from the underlying processes. Hence, the statistic complexity provides a statistical quantification of the statement ' is similarly complex as Y'. The presented approach, ultimately, transforms the classic problem of assessing the complexity of an object into the realm of statistics. This may open a wider applicability of this complexity measure to diverse application areas.

  14. Statistical distributions applications and parameter estimates

    CERN Document Server

    Thomopoulos, Nick T

    2017-01-01

    This book gives a description of the group of statistical distributions that have ample application to studies in statistics and probability.  Understanding statistical distributions is fundamental for researchers in almost all disciplines.  The informed researcher will select the statistical distribution that best fits the data in the study at hand.  Some of the distributions are well known to the general researcher and are in use in a wide variety of ways.  Other useful distributions are less understood and are not in common use.  The book describes when and how to apply each of the distributions in research studies, with a goal to identify the distribution that best applies to the study.  The distributions are for continuous, discrete, and bivariate random variables.  In most studies, the parameter values are not known a priori, and sample data is needed to estimate parameter values.  In other scenarios, no sample data is available, and the researcher seeks some insight that allows the estimate of ...

  15. Evaluation of PCR on bronchoalveolar lavage fluid for diagnosis of invasive aspergillosis: a bivariate metaanalysis and systematic review.

    Directory of Open Access Journals (Sweden)

    Wenkui Sun

    Full Text Available BACKGROUND: Nucleic acid detection by polymerase chain reaction (PCR is emerging as a sensitive and rapid diagnostic tool. PCR assays on serum have the potential to be a practical diagnostic tool. However, PCR on bronchoalveolar lavage fluid (BALF has not been well established. We performed a systematic review of published studies to evaluate the diagnostic accuracy of PCR assays on BALF for invasive aspergillosis (IA. METHODS: Relevant published studies were shortlisted to evaluate the quality of their methodologies. A bivariate regression approach was used to calculate pooled values of the method sensitivity, specificity, and positive and negative likelihood ratios. Hierarchical summary receiver operating characteristic curves were used to summarize overall performance. We calculated the post-test probability to evaluate clinical usefulness. Potential heterogeneity among studies was explored by subgroup analyses. RESULTS: Seventeen studies comprising 1191 at-risk patients were selected. The summary estimates of the BALF-PCR assay for proven and probable IA were as follows: sensitivity, 0.91 (95% confidence interval (CI, 0.79-0.96; specificity, 0.92 (95% CI, 0.87-0.96; positive likelihood ratio, 11.90 (95% CI, 6.80-20.80; and negative likelihood ratio, 0.10 (95% CI, 0.04-0.24. Subgroup analyses showed that the performance of the PCR assay was influenced by PCR assay methodology, primer design and the methods of cell wall disruption and DNA extraction. CONCLUSIONS: PCR assay on BALF is highly accurate for diagnosing IA in immunocompromised patients and is likely to be a useful diagnostic tool. However, further efforts towards devising a standard protocol are needed to enable formal validation of BALF-PCR.

  16. Modeling mood variation and covariation among adolescent smokers: application of a bivariate location-scale mixed-effects model.

    Science.gov (United States)

    Pugach, Oksana; Hedeker, Donald; Richmond, Melanie J; Sokolovsky, Alexander; Mermelstein, Robin

    2014-05-01

    Ecological momentary assessments (EMAs) are useful for understanding both between- and within-subject dynamic changes in smoking and mood. Modeling 2 moods (positive affect [PA] and negative affect [NA], PA and NA) simultaneously will better enable researchers to explore the association between mood variables and what influences them at both the momentary and subject level. The EMA component of a natural history study of adolescent smoking was analyzed with a bivariate location-scale mixed-effects model. The proposed model separately estimates the between- and within-subject variances and jointly models the 2 mood constructs. A total of 461 adolescents completed the baseline EMA wave, which resulted in 14,105 random prompts. Smoking level, represented by the number of smoking events on EMA, entered the model as 2 predictors: one that compared nonsmokers during the EMA week to 1-cigarette smokers, and the second one that estimated the effect of smoking level on mood among smokers. Results suggest that nonsmokers had more consistent positive and negative moods compared to 1-cigarette smokers. Among those who smoked, both moods were more consistent at higher smoking levels. The effects of smoking level were greater for NA than for PA. The within-subject association between mood constructs was negative and strongest among 1-cigarette smokers; the within-subject association between positive and negative moods was negatively associated with smoking. Mood variation and association between mood constructs varied across smoking levels. The most infrequent smokers were characterized with more inconsistent moods, whereas mood was more consistent for subjects with higher smoking levels.

  17. Childhood Cancer Statistics

    Science.gov (United States)

    ... Financial Reports Watchdog Ratings Feedback Contact Select Page Childhood Cancer Statistics Home > Cancer Resources > Childhood Cancer Statistics Childhood Cancer Statistics – Graphs and Infographics Number of Diagnoses ...

  18. MQSA National Statistics

    Science.gov (United States)

    ... Standards Act and Program MQSA Insights MQSA National Statistics Share Tweet Linkedin Pin it More sharing options ... but should level off with time. Archived Scorecard Statistics 2018 Scorecard Statistics 2017 Scorecard Statistics 2016 Scorecard ...

  19. An assessment of non-randomized medical treatment of long-term schizophrenia relapse using bivariate binary-response transition models.

    Science.gov (United States)

    Ten Have, Thomas R; Morabia, Alfredo

    2002-03-01

    The analyses of observational longitudinal studies involving concurrent changes in treatment and medical conditions present difficulties because of the multitude of directions of potential relationships: past medication influences current symptoms; past symptoms influence current medication; and current medication is associated with current symptoms. In the context of a long-term study of non-randomized pharmacological treatment of schizophrenic relapse, we present an analysis of bivariate discrete-time transitional data with binary responses in an attempt to understand the transitional and concurrent relationships between schizophrenia relapse and medication use. A naive analysis does not show any association between previous medication and current relapse. However, we provide evidence suggesting that current treatment may impact current relapse for those who have previously taken medication, but not for those who haven't taken medication in the past. When univariate models are specified to assess these associations, the bivariate nature of the problem requires a choice of which response, relapse or medication, should be the dependent variable. In this case, the choice of relapse or medication as a dependent variable does matter. Hence, our results derive from models where both relapse and medication are treated as dependent variables. Specifically, we specify a bivariate log odds ratio for current relapse and current medication use and a separate univariate logit component for each of these outcomes. Each of these components contains transitional associations with previous relapse and medication. Such models represent extensions of univariate transitional association models (e.g. Diggle et al. (1994)) and correspond to bivariate transitional models (e.g. Zeger and Liang (1991)). We incorporate changes in transitional associations into the full-data parametric model for final inference, and investigate if these temporal changes are due to learning effects or the

  20. Sampling, Probability Models and Statistical Reasoning Statistical ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 5. Sampling, Probability Models and Statistical Reasoning Statistical Inference. Mohan Delampady V R Padmawar. General Article Volume 1 Issue 5 May 1996 pp 49-58 ...

  1. Study of the effect of shell stabilization of the collective isovector valence-shell excitations along the N=80 isotonic chain

    CERN Multimedia

    Blazhev, A A; Kruecken, R; Coquard, L; Bloch, T P; Wadsworth, R; Danchev, M T; Jenkins, D G; Kroell, T; Leske, J

    It is proposed to initiate an experimental program to study the quadrupole-collective isovector valence-shell excitations the so-called mixed-symmetry states (MSSs) of unstable nuclei from the N = 80 isotonic chain. The main aim of this program is to investigate the microscopic mechanism which leads to a concentration or a fragmentation of the MSSs, an effect dubbed $\\textit{shell stabilization}$ of MSSs. This will be achieved by identification of MSSs of the unstable nuclei $^{140}$Nd and $^{142}$Sm. The MSSs of these nuclei will be identified experimentally by measuring their relative populations with respect to the population of the first 2$^{+}$ states in inverse kinematics Coulomb excitation (CE) reactions on light targets. As a first step of this program we apply for a beam time for the radioactive $^{140}$Nd and $^{142}$Sm beams at beam energy of 2.85 MeV/u. These beams will be used to determine the absolute B(E2;2$_{1}^{+} \\rightarrow$ 0$_{1}^{+}$) values for $^{140}$Nd and $^{142}$Sm in Coulomb excit...

  2. Effect of isotonic versus hypotonic maintenance fluid therapy on urine output, fluid balance, and electrolyte homeostasis: a crossover study in fasting adult volunteers.

    Science.gov (United States)

    Van Regenmortel, N; De Weerdt, T; Van Craenenbroeck, A H; Roelant, E; Verbrugghe, W; Dams, K; Malbrain, M L N G; Van den Wyngaert, T; Jorens, P G

    2017-06-01

    Daily and globally, millions of adult hospitalized patients are exposed to maintenance i.v. fluid solutions supported by limited scientific evidence. In particular, it remains unclear whether fluid tonicity contributes to the recently established detrimental effects of fluid, sodium, and chloride overload. This crossover study consisted of two 48 h study periods, during which 12 fasting healthy adults were treated with a frequently prescribed solution (NaCl 0.9% in glucose 5% supplemented by 40 mmol litre -1 of potassium chloride) and a premixed hypotonic fluid (NaCl 0.32% in glucose 5% containing 26 mmol litre -1 of potassium) at a daily rate of 25 ml kg -1 of body weight. The primary end point was cumulative urine volume; fluid balance was thus calculated. We also explored the physiological mechanisms behind our findings and assessed electrolyte concentrations. After 48 h, 595 ml (95% CI: 454-735) less urine was voided with isotonic fluids than hypotonic fluids ( P hypotonic solutions and were associated with hyperchloraemia. Despite their lower sodium and potassium content, hypotonic fluids were not associated with hyponatraemia or hypokalaemia. ClinicalTrials.gov (NCT02822898) and EudraCT (2016-001846-24).

  3. Fractional calculus approach to the statistical characterization of random variables and vectors

    OpenAIRE

    Cottone, D. ; Paola, M.D.

    2015-01-01

    Fractional moments have been investigated by many authors to represent the density of univariate and bivariate random variables in different contexts. Fractional moments are indeed important when the density of the random variable has inverse power-law tails and, consequently, it lacks integer order moments. In this paper, starting from the Mellin transform of the characteristic function and by fractional calculus method we present a new perspective on the statistics of random variables. Intr...

  4. Reliability Implications in Wood Systems of a Bivariate Gaussian-Weibull Distribution and the Associated Univariate Pseudo-truncated Weibull

    Science.gov (United States)

    Steve P. Verrill; James W. Evans; David E. Kretschmann; Cherilyn A. Hatfield

    2014-01-01

    Two important wood properties are the modulus of elasticity (MOE) and the modulus of rupture (MOR). In the past, the statistical distribution of the MOE has often been modeled as Gaussian, and that of the MOR as lognormal or as a two- or three-parameter Weibull distribution. It is well known that MOE and MOR are positively correlated. To model the simultaneous behavior...

  5. Intraoperative corneal thickness monitoring during corneal collagen cross-linking with isotonic riboflavin solution with and without dextran.

    Science.gov (United States)

    Oltulu, Refik; Şatirtav, Günhal; Donbaloğlu, Meryem; Kerimoğlu, Hürkan; Özkağnici, Ahmet; Karaibrahimoğlu, Adnan

    2014-11-01

    The aim of this study was to analyze and compare corneal thickness changes during corneal collagen cross-linking procedures performed with isoosmolar riboflavin solution with 20% dextran and without dextran in corneal ectatic diseases. The patients in this study were analyzed in 2 groups: group 1 receiving riboflavin solution containing 20% dextran and group 2 receiving dextran-free riboflavin solution. Corneal thickness measurements were obtained with ultrasonic pachymetry at 6 different time points: preoperatively and at 0, 15, 30, 45, and 60 minutes after epithelial removal and initiation of ultraviolet A irradiation. Twenty-seven eyes of 27 patients with progressive keratoconus were included in the study. In group 1 (n = 13), the mean preoperative thinnest pachymetric readings were 469.3 ± 8.5 μm, which decreased to 423.8 ± 8.9 μm after deepithelization and further decreased to 385.9 ± 10.9 μm at 15 minutes. The corneal thickness assumed a steady course at the 30-, 45-, and 60-minute measurements (378.9 ± 9.8 μm, 384.5 ± 10.5 μm, and 396.7 ± 9.4 μm, respectively). The initial change was statistically significant (P corneas.

  6. Algebraic statistics computational commutative algebra in statistics

    CERN Document Server

    Pistone, Giovanni; Wynn, Henry P

    2000-01-01

    Written by pioneers in this exciting new field, Algebraic Statistics introduces the application of polynomial algebra to experimental design, discrete probability, and statistics. It begins with an introduction to Gröbner bases and a thorough description of their applications to experimental design. A special chapter covers the binary case with new application to coherent systems in reliability and two level factorial designs. The work paves the way, in the last two chapters, for the application of computer algebra to discrete probability and statistical modelling through the important concept of an algebraic statistical model.As the first book on the subject, Algebraic Statistics presents many opportunities for spin-off research and applications and should become a landmark work welcomed by both the statistical community and its relatives in mathematics and computer science.

  7. What are the statistics in statistical learning?

    Science.gov (United States)

    Holt, Lori L.; Lotto, Andrew J.

    2003-10-01

    The idea that speech perception is shaped by the statistical structure of the input is gaining wide enthusiasm and growing empirical support. Nonetheless, statistics and statistical learning are broad terms with many possible interpretations and, perhaps, many potential underlying mechanisms. In order to define the role of statistics in speech perception mechanistically, we will need to more precisely define the statistics of statistical learning and examine similarities and differences across subgroups. In this talk, we examine learning of four types of information: (1) acoustic variance that is defining for contrastive categories, (2) the correlation between acoustic attributes or linguistic features, (3) the probability or frequency of events or a series of events, (4) the shape of input distributions. We present representative data from online speech perception and speech development and discuss inter-relationships among the subgroups. [Work supported by NSF, NIH and the James S. McDonnell Foundation.

  8. Blood Facts and Statistics

    Science.gov (United States)

    ... Blood > Blood Facts and Statistics Blood Facts and Statistics Facts about blood needs Facts about the blood ... to Top Learn About Blood Blood Facts and Statistics Blood Components Whole Blood and Red Blood Cells ...

  9. Adrenal Gland Tumors: Statistics

    Science.gov (United States)

    ... Gland Tumor: Statistics Request Permissions Adrenal Gland Tumor: Statistics Approved by the Cancer.Net Editorial Board , 03/ ... primary adrenal gland tumor is very uncommon. Exact statistics are not available for this type of tumor ...

  10. State transportation statistics 2009

    Science.gov (United States)

    2009-01-01

    The Bureau of Transportation Statistics (BTS), a part of DOTs Research and : Innovative Technology Administration (RITA), presents State Transportation : Statistics 2009, a statistical profile of transportation in the 50 states and the : District ...

  11. Neuroendocrine Tumor: Statistics

    Science.gov (United States)

    ... Tumor > Neuroendocrine Tumor: Statistics Request Permissions Neuroendocrine Tumor: Statistics Approved by the Cancer.Net Editorial Board , 11/ ... the body. It is important to remember that statistics on the survival rates for people with a ...

  12. The foundations of statistics

    CERN Document Server

    Savage, Leonard J

    1972-01-01

    Classic analysis of the foundations of statistics and development of personal probability, one of the greatest controversies in modern statistical thought. Revised edition. Calculus, probability, statistics, and Boolean algebra are recommended.

  13. Generalized Fractional Statistics

    OpenAIRE

    Kaniadakis, G.; A. Lavagno(Politecnico di Torino and INFN Sezione di Torino, Torino Italy); Quarati, P.

    1996-01-01

    We link, by means of a semiclassical approach, the fractional statistics of particles obeying the Haldane exclusion principle to the Tsallis statistics and derive a generalized quantum entropy and its associated statistics.

  14. The use of bivariate spatial modeling of questionnaire and parasitology data to predict the distribution of Schistosoma haematobium in Coastal Kenya.

    Directory of Open Access Journals (Sweden)

    Hugh J W Sturrock

    Full Text Available Questionnaires of reported blood in urine (BIU distributed through the existing school system provide a rapid and reliable method to classify schools according to the prevalence of Schistosoma haematobium, thereby helping in the targeting of schistosomiasis control. However, not all schools return questionnaires and it is unclear whether treatment is warranted in such schools. This study investigates the use of bivariate spatial modelling of available and multiple data sources to predict the prevalence of S. haematobium at every school along the Kenyan coast.Data from a questionnaire survey conducted by the Kenya Ministry of Education in Coast Province in 2009 were combined with available parasitological and environmental data in a Bayesian bivariate spatial model. This modeled the relationship between BIU data and environmental covariates, as well as the relationship between BIU and S. haematobium infection prevalence, to predict S. haematobium infection prevalence at all schools in the study region. Validation procedures were implemented to assess the predictive accuracy of endemicity classification.The prevalence of BIU was negatively correlated with distance to nearest river and there was considerable residual spatial correlation at small (~15 km spatial scales. There was a predictable relationship between the prevalence of reported BIU and S. haematobium infection. The final model exhibited excellent sensitivity (0.94 but moderate specificity (0.69 in identifying low (<10% prevalence schools, and had poor performance in differentiating between moderate and high prevalence schools (sensitivity 0.5, specificity 1.Schistosomiasis is highly focal and there is a need to target treatment on a school-by-school basis. The use of bivariate spatial modelling can supplement questionnaire data to identify schools requiring mass treatment, but is unable to distinguish between moderate and high prevalence schools.

  15. Evaluating the effect of administrating hypertonic and isotonic saline solutions on clinical improvement, serum electrolyte concentrations and renal function of calves affected by diarrhea

    Directory of Open Access Journals (Sweden)

    A Hasanpour

    2009-11-01

    This study was conducted on 40 calves under the age of one mouth with 30 calves affected by diarrhea allocated to 3 treatment groups of 10 calves each and the control group consisting of 10 calves. The control group received neither treatment nor any injections. In the first treatment group, only antibiotics were administered without any fluid therapy. In the second treatment group, apart from antibiotic therapy of diarrhea, hypertonic saline solution (7.5% was administered at a dose of 5 ml/kg as slow intravenous infusion alongside oral ORS solution whereas in the third treatment group isotonic saline solution (0.9% was given intravenously according to the formula (Body weight × %Dehydration alongside oral ORS solution. In all groups, clinical examination and blood sampling was undertaken at times 0, 1, 2, 8 and 24 hours following treatment. At time 0, the diarrhea had resulted in clinical and laboratory signs such as a fever, the dehydration, tachycardia, oligopnea, increased packed sell volume, hypernatremia, hyperchloremia, hyperkalemia, hyperphosphatemia, hypercalcemia, increased serum creatinine and BUN values. Following treatment, fever subsided and the dehydration was corrected and this correction occurred faster in calves which had received hypertonic saline solution. Correction of sodium, potassium, chloride, phosphorus and calsium imbalance occurred faster in patients which were treated by hypertonic solution. Fluid therapy with saline solutions prevented the increase in serum creatinine and BUN values. In conclusion, the administration of hypertonic saline solutions leads to much faster and more reliable clinical improvement and electrolyte imbalance correction in calves affected by diarrhea.

  16. Characteristics of urine sodium and potassium after oral ingestion of solutions containing sodium and potassium which is isotonic to the physiological saline--a quantitative study.

    Science.gov (United States)

    Nishimuta, Mamoru

    2006-10-01

    The effects of orally ingesting 500 mL of four kinds of test solutions that were isotonic to physiological saline (i.e., containing sodium (Na) and potassium (K) as chloride with Na/K molar ratios of 1, 2, 3 and 4) on urine flow, Na and K excretions from Japanese male students were investigated. The subjects assembled at the National Institute of Nutrition the day before the oral ingestions, which were conducted three times for each subject. They were permitted to eat freely until 8:00 pm, and then the intake of food and drinks except tap water was prohibited until 10:00 pm. After that, no food or drinks except the test solution used, were permitted to be ingested until the end of the final collection of urine. Subjects were woken up at 7:00 am the next morning, at which time they emptied their bladder. At 8:00 am, after sampling control urine before ingestion, they ingested 500 mL of water, the physiological saline or one of the test solutions. Urine was collected every 30 min for 4 h after ingestion. Urine flow was significantly higher for those who drank solutions Na/ K = 1 and 2 than those who drank the saline (paired-t test), but that for those who drank solutions Na/K = 3 and 4 was not significantly higher. For those who drank solution Na/ k=2, urine Na was significantly higher than that of those who drank the saline 30 to 60 min after ingestion. An increase in urine flow after K ingestion may be an essential factor for K-induced Na uresis.

  17. Stan: Statistical inference

    Science.gov (United States)

    Stan Development Team

    2018-01-01

    Stan facilitates statistical inference at the frontiers of applied statistics and provides both a modeling language for specifying complex statistical models and a library of statistical algorithms for computing inferences with those models. These components are exposed through interfaces in environments such as R, Python, and the command line.

  18. Statistics using R

    CERN Document Server

    Purohit, Sudha G; Deshmukh, Shailaja R

    2015-01-01

    STATISTICS USING R will be useful at different levels, from an undergraduate course in statistics, through graduate courses in biological sciences, engineering, management and so on. The book introduces statistical terminology and defines it for the benefit of a novice. For a practicing statistician, it will serve as a guide to R language for statistical analysis. For a researcher, it is a dual guide, simultaneously explaining appropriate statistical methods for the problems at hand and indicating how these methods can be implemented using the R language. For a software developer, it is a guide in a variety of statistical methods for development of a suite of statistical procedures.

  19. A Hybrid Forecasting Model Based on Bivariate Division and a Backpropagation Artificial Neural Network Optimized by Chaos Particle Swarm Optimization for Day-Ahead Electricity Price

    Directory of Open Access Journals (Sweden)

    Zhilong Wang

    2014-01-01

    Full Text Available In the electricity market, the electricity price plays an inevitable role. Nevertheless, accurate price forecasting, a vital factor affecting both government regulatory agencies and public power companies, remains a huge challenge and a critical problem. Determining how to address the accurate forecasting problem becomes an even more significant task in an era in which electricity is increasingly important. Based on the chaos particle swarm optimization (CPSO, the backpropagation artificial neural network (BPANN, and the idea of bivariate division, this paper proposes a bivariate division BPANN (BD-BPANN method and the CPSO-BD-BPANN method for forecasting electricity price. The former method creatively transforms the electricity demand and price to be a new variable, named DV, which is calculated using the division principle, to forecast the day-ahead electricity by multiplying the forecasted values of the DVs and forecasted values of the demand. Next, to improve the accuracy of BD-BPANN, chaos particle swarm optimization and BD-BPANN are synthesized to form a novel model, CPSO-BD-BPANN. In this study, CPSO is utilized to optimize the initial parameters of BD-BPANN to make its output more stable than the original model. Finally, two forecasting strategies are proposed regarding different situations.

  20. The efficacy of hypotonic and near-isotonic saline for parenteral fluid therapy given at low maintenance rate in preventing significant change in plasma sodium in post-operative pediatric patients: protocol for a prospective randomized non-blinded study

    Directory of Open Access Journals (Sweden)

    Stigzelius Shayarina

    2011-07-01

    Full Text Available Abstract Background Hyponatremia is the most frequent electrolyte abnormality observed in post-operative pediatric patients receiving intravenous maintenance fluid therapy. If plasma sodium concentration (p-Na+ declines to levels below 125 mmol/L in vs. restricted rate of infusion and the composition of solutions used for parenteral maintenance fluid therapy (hypotonic vs. isotonic solutions contribute to the development of hyponatremia. So far, there is no definitive pediatric data to support a particular choice of parenteral fluid for maintenance therapy in post-surgical patients. Methods/Design Our prospective randomized non-blinded study will be conducted in healthy children and adolescents aged 1 to 14 years who have been operated for acute appendicitis. Patients will be randomized either to intravenous hypotonic (0.23% or 0.40% sodium chloride in glucose, respectively or near-isotonic (0.81% sodium chloride in glucose solution given at approximately three-fourths of the average maintenance rate. The main outcome of interest from this study is to evaluate 24 h post-operatively whether differences in p-Na+ between treatment groups are large enough to be of clinical relevance. In addition, water and electrolyte balance as well as regulatory hormones will be measured. Discussion This study will provide valuable information on the efficacy of hypotonic and near-isotonic fluid therapy in preventing a significant decrease in p-Na+. Finally, by means of careful electrolyte and water balance and by measuring regulatory hormones our results will also contribute to a better understanding of the physiopathology of post-operative changes in p-Na+ in a population at risk for hyponatremia. Trial registration The protocol for this study is registered with the current controlled trials registry; registry number: ISRCTN43896775.

  1. Statistics For Dummies

    CERN Document Server

    Rumsey, Deborah

    2011-01-01

    The fun and easy way to get down to business with statistics Stymied by statistics? No fear ? this friendly guide offers clear, practical explanations of statistical ideas, techniques, formulas, and calculations, with lots of examples that show you how these concepts apply to your everyday life. Statistics For Dummies shows you how to interpret and critique graphs and charts, determine the odds with probability, guesstimate with confidence using confidence intervals, set up and carry out a hypothesis test, compute statistical formulas, and more.Tracks to a typical first semester statistics cou

  2. Industrial statistics with Minitab

    CERN Document Server

    Cintas, Pere Grima; Llabres, Xavier Tort-Martorell

    2012-01-01

    Industrial Statistics with MINITAB demonstrates the use of MINITAB as a tool for performing statistical analysis in an industrial context. This book covers introductory industrial statistics, exploring the most commonly used techniques alongside those that serve to give an overview of more complex issues. A plethora of examples in MINITAB are featured along with case studies for each of the statistical techniques presented. Industrial Statistics with MINITAB: Provides comprehensive coverage of user-friendly practical guidance to the essential statistical methods applied in industry.Explores

  3. Sea spray aerosol flux estimation based on long-term variation of wave statistics

    Directory of Open Access Journals (Sweden)

    Dag Myrhaug

    2015-07-01

    Full Text Available This note provides estimates of the mean sea spray aerosol flux based on long-term wave statistics using the whitecap method based on the limiting steepness and threshold vertical acceleration criteria. The aim is to present a procedure demonstrating how global wave statistics can be used to give estimates of the long-term aerosol flux. These estimates are obtained by using bivariate distributions of significant wave height and characteristic wave period, representing open ocean deep water waves in the Northern North Sea and the North Atlantic.

  4. Statistics for Finance

    DEFF Research Database (Denmark)

    Lindström, Erik; Madsen, Henrik; Nielsen, Jan Nygaard

    Statistics for Finance develops students’ professional skills in statistics with applications in finance. Developed from the authors’ courses at the Technical University of Denmark and Lund University, the text bridges the gap between classical, rigorous treatments of financial mathematics...

  5. CMS Program Statistics

    Data.gov (United States)

    U.S. Department of Health & Human Services — The CMS Office of Enterprise Data and Analytics has developed CMS Program Statistics, which includes detailed summary statistics on national health care, Medicare...

  6. Recreational Boating Statistics 2012

    Data.gov (United States)

    Department of Homeland Security — Every year, the USCG compiles statistics on reported recreational boating accidents. These statistics are derived from accident reports that are filed by the owners...

  7. Recreational Boating Statistics 2011

    Data.gov (United States)

    Department of Homeland Security — Every year, the USCG compiles statistics on reported recreational boating accidents. These statistics are derived from accident reports that are filed by the owners...

  8. Recreational Boating Statistics 2013

    Data.gov (United States)

    Department of Homeland Security — Every year, the USCG compiles statistics on reported recreational boating accidents. These statistics are derived from accident reports that are filed by the owners...

  9. Statistical data analysis handbook

    National Research Council Canada - National Science Library

    Wall, Francis J

    1986-01-01

    It must be emphasized that this is not a text book on statistics. Instead it is a working tool that presents data analysis in clear, concise terms which can be readily understood even by those without formal training in statistics...

  10. Mathematical and statistical analysis

    Science.gov (United States)

    Houston, A. Glen

    1988-01-01

    The goal of the mathematical and statistical analysis component of RICIS is to research, develop, and evaluate mathematical and statistical techniques for aerospace technology applications. Specific research areas of interest include modeling, simulation, experiment design, reliability assessment, and numerical analysis.

  11. National transportation statistics 2011

    Science.gov (United States)

    2011-04-01

    Compiled and published by the U.S. Department of Transportation's Bureau of Transportation Statistics (BTS), National Transportation Statistics presents information on the U.S. transportation system, including its physical components, safety record, ...

  12. Principles of applied statistics

    National Research Council Canada - National Science Library

    Cox, D. R; Donnelly, Christl A

    2011-01-01

    .... David Cox and Christl Donnelly distil decades of scientific experience into usable principles for the successful application of statistics, showing how good statistical strategy shapes every stage of an investigation...

  13. Neutron effective single-particle energies above 78Ni: A hint from lifetime measurements in the N =51 isotones 85Se and 87Kr

    Science.gov (United States)

    Didierjean, F.; Verney, D.; Duchêne, G.; Litzinger, J.; Sieja, K.; Dewald, A.; Goasduff, A.; Lozeva, R.; Fransen, C.; de Angelis, G.; Aydin, S.; Bazzacco, D.; Bracco, A.; Bottoni, S.; Corradi, L.; Crespi, F.; Ellinger, E.; Farnea, E.; Fioretto, E.; Franchoo, S.; Gottardo, A.; Grocutt, L.; Hackstein, M.; Ibrahim, F.; Kolos, K.; Leoni, S.; Lenzi, S.; Lunardi, S.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Mijatovic, T.; Modamio, V.; Möller, O.; Montagnoli, G.; Montanari, D.; Morales, A. I.; Napoli, D.; Niikura, M.; Recchia, F.; Sahin, E.; Scarlassara, F.; Sengele, L.; Szilner, S.; Smith, J. F.; Stefanini, A. M.; Ur, C.; Valiente-Dobón, J. J.; Vandone, V.

    2017-10-01

    Background: While the N =50 shell-gap evolution towards 78Ni is presently in the focus of nuclear structure research, experimental information on the neutron effective single-particle energy sequence above the 78Ni core remain scarce. Direct nucleon-exchange reactions are indeed difficult with presently available post-accelerated radioactive-ion beams (especially for high orbital-momentum orbitals) in this exotic region. Purpose: In this study we probe the evolution of the ν 1 g7 /2 effective single-particle energy which is a key to understanding the possible evolution of the spin-orbit splitting due to the proton-neutron interaction in the 78Ni region. To achieve this goal, a method based on lifetime measurements is used for the first time. The obtained lifetimes of the 7 /21+ states in 87Kr and 85Se are used to investigate the ν 1 g7 /2 evolution. Method: Yrast and near-yrast states in the light N =51 isotones 85Se and 87Kr were populated via multinucleon transfer reactions, using a 82Se beam and a 238U target at the LNL tandem-ALPI facility. The prompt γ rays were detected by the AGATA Demonstrator and particle identification was performed using the PRISMA spectrometer. Lifetime measurements were performed by using the Cologne plunger device for deep inelastic reactions and the Recoil Distance Doppler Shift technique. Results: We obtain τ(7 /21+)=0 .4-0.4+1.6 ps for 87Kr. In the case of 85Se an upper limit of 3(2) ps is obtained for the τ7 /21+ value. Conclusion: For 87Kr, the measured (7 /21+) lifetime is consistent with a core-coupled 2+⊗ν 2 d5 /2 configuration for this state. This result is consistent with that obtained by direct reaction, which validates our method. For 85Se, the measured 7 /21+ lifetime limit indicates a very small contribution of the ν 1 g7 /2 configuration to the wave function of this state.

  14. Ethics in Statistics

    Science.gov (United States)

    Lenard, Christopher; McCarthy, Sally; Mills, Terence

    2014-01-01

    There are many different aspects of statistics. Statistics involves mathematics, computing, and applications to almost every field of endeavour. Each aspect provides an opportunity to spark someone's interest in the subject. In this paper we discuss some ethical aspects of statistics, and describe how an introduction to ethics has been…

  15. Contributory fault and level of personal injury to drivers involved in head-on collisions: Application of copula-based bivariate ordinal models.

    Science.gov (United States)

    Wali, Behram; Khattak, Asad J; Xu, Jingjing

    2018-01-01

    The main objective of this study is to simultaneously investigate the degree of injury severity sustained by drivers involved in head-on collisions with respect to fault status designation. This is complicated to answer due to many issues, one of which is the potential presence of correlation between injury outcomes of drivers involved in the same head-on collision. To address this concern, we present seemingly unrelated bivariate ordered response models by analyzing the joint injury severity probability distribution of at-fault and not-at-fault drivers. Moreover, the assumption of bivariate normality of residuals and the linear form of stochastic dependence implied by such models may be unduly restrictive. To test this, Archimedean copula structures and normal mixture marginals are integrated into the joint estimation framework, which can characterize complex forms of stochastic dependencies and non-normality in residual terms. The models are estimated using 2013 Virginia police reported two-vehicle head-on collision data, where exactly one driver is at-fault. The results suggest that both at-fault and not-at-fault drivers sustained serious/fatal injuries in 8% of crashes, whereas, in 4% of the cases, the not-at-fault driver sustained a serious/fatal injury with no injury to the at-fault driver at all. Furthermore, if the at-fault driver is fatigued, apparently asleep, or has been drinking the not-at-fault driver is more likely to sustain a severe/fatal injury, controlling for other factors and potential correlations between the injury outcomes. While not-at-fault vehicle speed affects injury severity of at-fault driver, the effect is smaller than the effect of at-fault vehicle speed on at-fault injury outcome. Contrarily, and importantly, the effect of at-fault vehicle speed on injury severity of not-at-fault driver is almost equal to the effect of not-at-fault vehicle speed on injury outcome of not-at-fault driver. Compared to traditional ordered probability

  16. Nonparametric statistical inference

    CERN Document Server

    Gibbons, Jean Dickinson

    2010-01-01

    Overall, this remains a very fine book suitable for a graduate-level course in nonparametric statistics. I recommend it for all people interested in learning the basic ideas of nonparametric statistical inference.-Eugenia Stoimenova, Journal of Applied Statistics, June 2012… one of the best books available for a graduate (or advanced undergraduate) text for a theory course on nonparametric statistics. … a very well-written and organized book on nonparametric statistics, especially useful and recommended for teachers and graduate students.-Biometrics, 67, September 2011This excellently presente

  17. Business statistics for dummies

    CERN Document Server

    Anderson, Alan

    2013-01-01

    Score higher in your business statistics course? Easy. Business statistics is a common course for business majors and MBA candidates. It examines common data sets and the proper way to use such information when conducting research and producing informational reports such as profit and loss statements, customer satisfaction surveys, and peer comparisons. Business Statistics For Dummies tracks to a typical business statistics course offered at the undergraduate and graduate levels and provides clear, practical explanations of business statistical ideas, techniques, formulas, and calculations, w

  18. Head First Statistics

    CERN Document Server

    Griffiths, Dawn

    2009-01-01

    Wouldn't it be great if there were a statistics book that made histograms, probability distributions, and chi square analysis more enjoyable than going to the dentist? Head First Statistics brings this typically dry subject to life, teaching you everything you want and need to know about statistics through engaging, interactive, and thought-provoking material, full of puzzles, stories, quizzes, visual aids, and real-world examples. Whether you're a student, a professional, or just curious about statistical analysis, Head First's brain-friendly formula helps you get a firm grasp of statistics

  19. Statistics & probaility for dummies

    CERN Document Server

    Rumsey, Deborah J

    2013-01-01

    Two complete eBooks for one low price! Created and compiled by the publisher, this Statistics I and Statistics II bundle brings together two math titles in one, e-only bundle. With this special bundle, you'll get the complete text of the following two titles: Statistics For Dummies, 2nd Edition  Statistics For Dummies shows you how to interpret and critique graphs and charts, determine the odds with probability, guesstimate with confidence using confidence intervals, set up and carry out a hypothesis test, compute statistical formulas, and more. Tra

  20. Statistics in a nutshell

    CERN Document Server

    Boslaugh, Sarah

    2013-01-01

    Need to learn statistics for your job? Want help passing a statistics course? Statistics in a Nutshell is a clear and concise introduction and reference for anyone new to the subject. Thoroughly revised and expanded, this edition helps you gain a solid understanding of statistics without the numbing complexity of many college texts. Each chapter presents easy-to-follow descriptions, along with graphics, formulas, solved examples, and hands-on exercises. If you want to perform common statistical analyses and learn a wide range of techniques without getting in over your head, this is your book.

  1. Statistics for Research

    CERN Document Server

    Dowdy, Shirley; Chilko, Daniel

    2011-01-01

    Praise for the Second Edition "Statistics for Research has other fine qualities besides superior organization. The examples and the statistical methods are laid out with unusual clarity by the simple device of using special formats for each. The book was written with great care and is extremely user-friendly."-The UMAP Journal Although the goals and procedures of statistical research have changed little since the Second Edition of Statistics for Research was published, the almost universal availability of personal computers and statistical computing application packages have made it possible f

  2. Estimation and inferential statistics

    CERN Document Server

    Sahu, Pradip Kumar; Das, Ajit Kumar

    2015-01-01

    This book focuses on the meaning of statistical inference and estimation. Statistical inference is concerned with the problems of estimation of population parameters and testing hypotheses. Primarily aimed at undergraduate and postgraduate students of statistics, the book is also useful to professionals and researchers in statistical, medical, social and other disciplines. It discusses current methodological techniques used in statistics and related interdisciplinary areas. Every concept is supported with relevant research examples to help readers to find the most suitable application. Statistical tools have been presented by using real-life examples, removing the “fear factor” usually associated with this complex subject. The book will help readers to discover diverse perspectives of statistical theory followed by relevant worked-out examples. Keeping in mind the needs of readers, as well as constantly changing scenarios, the material is presented in an easy-to-understand form.

  3. Lectures on algebraic statistics

    CERN Document Server

    Drton, Mathias; Sullivant, Seth

    2009-01-01

    How does an algebraic geometer studying secant varieties further the understanding of hypothesis tests in statistics? Why would a statistician working on factor analysis raise open problems about determinantal varieties? Connections of this type are at the heart of the new field of "algebraic statistics". In this field, mathematicians and statisticians come together to solve statistical inference problems using concepts from algebraic geometry as well as related computational and combinatorial techniques. The goal of these lectures is to introduce newcomers from the different camps to algebraic statistics. The introduction will be centered around the following three observations: many important statistical models correspond to algebraic or semi-algebraic sets of parameters; the geometry of these parameter spaces determines the behaviour of widely used statistical inference procedures; computational algebraic geometry can be used to study parameter spaces and other features of statistical models.

  4. Statistics for economics

    CERN Document Server

    Naghshpour, Shahdad

    2012-01-01

    Statistics is the branch of mathematics that deals with real-life problems. As such, it is an essential tool for economists. Unfortunately, the way you and many other economists learn the concept of statistics is not compatible with the way economists think and learn. The problem is worsened by the use of mathematical jargon and complex derivations. Here's a book that proves none of this is necessary. All the examples and exercises in this book are constructed within the field of economics, thus eliminating the difficulty of learning statistics with examples from fields that have no relation to business, politics, or policy. Statistics is, in fact, not more difficult than economics. Anyone who can comprehend economics can understand and use statistics successfully within this field, including you! This book utilizes Microsoft Excel to obtain statistical results, as well as to perform additional necessary computations. Microsoft Excel is not the software of choice for performing sophisticated statistical analy...

  5. Baseline Statistics of Linked Statistical Data

    NARCIS (Netherlands)

    Scharnhorst, Andrea; Meroño-Peñuela, Albert; Guéret, Christophe

    2014-01-01

    We are surrounded by an ever increasing ocean of information, everybody will agree to that. We build sophisticated strategies to govern this information: design data models, develop infrastructures for data sharing, building tool for data analysis. Statistical datasets curated by National

  6. National Statistical Commission and Indian Official Statistics

    Indian Academy of Sciences (India)

    T J Rao1. C. R. Rao Advanced Institute of Mathematics, Statistics and Computer Science (AIMSCS) University of Hyderabad Campus Central University Post Office, Prof. C. R. Rao Road Hyderabad 500 046, AP, India. Resonance – Journal of Science Education. Current Issue : Vol. 22, Issue 12 · Current Issue Volume 22 ...

  7. National Statistical Commission and Indian Official Statistics*

    Indian Academy of Sciences (India)

    IAS Admin

    Commission also stresses the importance of setting up of a. Methodological Study Unit to regularly undertake studies for bringing in improvements in the survey methodologies. The importance of a sound official statistical system in any country is well understood. Efficient governance depends largely on timely, accurate and ...

  8. Association of Supply Type with Fecal Contamination of Source Water and Household Stored Drinking Water in Developing Countries: A Bivariate Meta-analysis

    Science.gov (United States)

    Bain, Robert E.S.; Cronk, Ryan; Wright, Jim A.; Bartram, Jamie

    2015-01-01

    Background Access to safe drinking water is essential for health. Monitoring access to drinking water focuses on water supply type at the source, but there is limited evidence on whether quality differences at the source persist in water stored in the household. Objectives We assessed the extent of fecal contamination at the source and in household stored water (HSW) and explored the relationship between contamination at each sampling point and water supply type. Methods We performed a bivariate random-effects meta-analysis of 45 studies, identified through a systematic review, that reported either the proportion of samples free of fecal indicator bacteria and/or individual sample bacteria counts for source and HSW, disaggregated by supply type. Results Water quality deteriorated substantially between source and stored water. The mean percentage of contaminated samples (noncompliance) at the source was 46% (95% CI: 33, 60%), whereas mean noncompliance in HSW was 75% (95% CI: 64, 84%). Water supply type was significantly associated with noncompliance at the source (p Source water (OR = 0.2; 95% CI: 0.1, 0.5) and HSW (OR = 0.3; 95% CI: 0.2, 0.8) from piped supplies had significantly lower odds of contamination compared with non-piped water, potentially due to residual chlorine. Conclusions Piped water is less likely to be contaminated compared with other water supply types at both the source and in HSW. A focus on upgrading water services to piped supplies may help improve safety, including for those drinking stored water. Citation Shields KF, Bain RE, Cronk R, Wright JA, Bartram J. 2015. Association of supply type with fecal contamination of source water and household stored drinking water in developing countries: a bivariate meta-analysis. Environ Health Perspect 123:1222–1231; http://dx.doi.org/10.1289/ehp.1409002 PMID:25956006

  9. The statistical stability phenomenon

    CERN Document Server

    Gorban, Igor I

    2017-01-01

    This monograph investigates violations of statistical stability of physical events, variables, and processes and develops a new physical-mathematical theory taking into consideration such violations – the theory of hyper-random phenomena. There are five parts. The first describes the phenomenon of statistical stability and its features, and develops methods for detecting violations of statistical stability, in particular when data is limited. The second part presents several examples of real processes of different physical nature and demonstrates the violation of statistical stability over broad observation intervals. The third part outlines the mathematical foundations of the theory of hyper-random phenomena, while the fourth develops the foundations of the mathematical analysis of divergent and many-valued functions. The fifth part contains theoretical and experimental studies of statistical laws where there is violation of statistical stability. The monograph should be of particular interest to engineers...

  10. Statistical Physics An Introduction

    CERN Document Server

    Yoshioka, Daijiro

    2007-01-01

    This book provides a comprehensive presentation of the basics of statistical physics. The first part explains the essence of statistical physics and how it provides a bridge between microscopic and macroscopic phenomena, allowing one to derive quantities such as entropy. Here the author avoids going into details such as Liouville’s theorem or the ergodic theorem, which are difficult for beginners and unnecessary for the actual application of the statistical mechanics. In the second part, statistical mechanics is applied to various systems which, although they look different, share the same mathematical structure. In this way readers can deepen their understanding of statistical physics. The book also features applications to quantum dynamics, thermodynamics, the Ising model and the statistical dynamics of free spins.

  11. Guidelines for Statistical Testing

    OpenAIRE

    Strigini, L.; Littlewood, B.; European Space Agency

    1997-01-01

    This document provides an introduction to statistical testing. Statistical testing of software is here defined as testing in which the test cases are produced by a random process meant to produce different test cases with the same probabilities with which they would arise in actual use of the software. Statistical testing of software has these main advantages: for the purpose of reliability assessment and product acceptance, it supports directly estimates of reliability, and thus decisions on...

  12. Applied statistics for economists

    CERN Document Server

    Lewis, Margaret

    2012-01-01

    This book is an undergraduate text that introduces students to commonly-used statistical methods in economics. Using examples based on contemporary economic issues and readily-available data, it not only explains the mechanics of the various methods, it also guides students to connect statistical results to detailed economic interpretations. Because the goal is for students to be able to apply the statistical methods presented, online sources for economic data and directions for performing each task in Excel are also included.

  13. Equilibrium statistical mechanics

    CERN Document Server

    Mayer, J E

    1968-01-01

    The International Encyclopedia of Physical Chemistry and Chemical Physics, Volume 1: Equilibrium Statistical Mechanics covers the fundamental principles and the development of theoretical aspects of equilibrium statistical mechanics. Statistical mechanical is the study of the connection between the macroscopic behavior of bulk matter and the microscopic properties of its constituent atoms and molecules. This book contains eight chapters, and begins with a presentation of the master equation used for the calculation of the fundamental thermodynamic functions. The succeeding chapters highlight t

  14. Mathematical statistics with applications

    CERN Document Server

    Wackerly, Dennis D; Scheaffer, Richard L

    2008-01-01

    In their bestselling MATHEMATICAL STATISTICS WITH APPLICATIONS, premiere authors Dennis Wackerly, William Mendenhall, and Richard L. Scheaffer present a solid foundation in statistical theory while conveying the relevance and importance of the theory in solving practical problems in the real world. The authors' use of practical applications and excellent exercises helps you discover the nature of statistics and understand its essential role in scientific research.

  15. Contributions to statistics

    CERN Document Server

    Mahalanobis, P C

    1965-01-01

    Contributions to Statistics focuses on the processes, methodologies, and approaches involved in statistics. The book is presented to Professor P. C. Mahalanobis on the occasion of his 70th birthday. The selection first offers information on the recovery of ancillary information and combinatorial properties of partially balanced designs and association schemes. Discussions focus on combinatorial applications of the algebra of association matrices, sample size analogy, association matrices and the algebra of association schemes, and conceptual statistical experiments. The book then examines latt

  16. Optimization techniques in statistics

    CERN Document Server

    Rustagi, Jagdish S

    1994-01-01

    Statistics help guide us to optimal decisions under uncertainty. A large variety of statistical problems are essentially solutions to optimization problems. The mathematical techniques of optimization are fundamentalto statistical theory and practice. In this book, Jagdish Rustagi provides full-spectrum coverage of these methods, ranging from classical optimization and Lagrange multipliers, to numerical techniques using gradients or direct search, to linear, nonlinear, and dynamic programming using the Kuhn-Tucker conditions or the Pontryagin maximal principle. Variational methods and optimiza

  17. Equilibrium statistical mechanics

    CERN Document Server

    Jackson, E Atlee

    2000-01-01

    Ideal as an elementary introduction to equilibrium statistical mechanics, this volume covers both classical and quantum methodology for open and closed systems. Introductory chapters familiarize readers with probability and microscopic models of systems, while additional chapters describe the general derivation of the fundamental statistical mechanics relationships. The final chapter contains 16 sections, each dealing with a different application, ordered according to complexity, from classical through degenerate quantum statistical mechanics. Key features include an elementary introduction t

  18. Lectures on statistical mechanics

    CERN Document Server

    Bowler, M G

    1982-01-01

    Anyone dissatisfied with the almost ritual dullness of many 'standard' texts in statistical mechanics will be grateful for the lucid explanation and generally reassuring tone. Aimed at securing firm foundations for equilibrium statistical mechanics, topics of great subtlety are presented transparently and enthusiastically. Very little mathematical preparation is required beyond elementary calculus and prerequisites in physics are limited to some elementary classical thermodynamics. Suitable as a basis for a first course in statistical mechanics, the book is an ideal supplement to more convent

  19. Digest of education statistics

    National Research Council Canada - National Science Library

    Contains information on a variety of subjects within the field of education statistics, including the number of schools and colleges, enrollments, teachers, graduates, educational attainment, finances...

  20. Annual Statistical Supplement, 2002

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2002 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  1. Annual Statistical Supplement, 2003

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2003 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  2. Annual Statistical Supplement, 2001

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2001 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  3. Annual Statistical Supplement, 2010

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2010 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  4. Annual Statistical Supplement, 2007

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2007 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  5. Annual Statistical Supplement, 2016

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2016 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  6. Annual Statistical Supplement, 2000

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2000 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  7. Statistics in a Nutshell

    CERN Document Server

    Boslaugh, Sarah

    2008-01-01

    Need to learn statistics as part of your job, or want some help passing a statistics course? Statistics in a Nutshell is a clear and concise introduction and reference that's perfect for anyone with no previous background in the subject. This book gives you a solid understanding of statistics without being too simple, yet without the numbing complexity of most college texts. You get a firm grasp of the fundamentals and a hands-on understanding of how to apply them before moving on to the more advanced material that follows. Each chapter presents you with easy-to-follow descriptions illustrat

  8. Annual Statistical Supplement, 2008

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2008 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  9. Annual Statistical Supplement, 2006

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2006 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  10. Annual Statistical Supplement, 2005

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2005 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  11. Annual Statistical Supplement, 2015

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2015 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  12. Statistics is Easy

    CERN Document Server

    Shasha, Dennis

    2010-01-01

    Statistics is the activity of inferring results about a population given a sample. Historically, statistics books assume an underlying distribution to the data (typically, the normal distribution) and derive results under that assumption. Unfortunately, in real life, one cannot normally be sure of the underlying distribution. For that reason, this book presents a distribution-independent approach to statistics based on a simple computational counting idea called resampling. This book explains the basic concepts of resampling, then systematically presents the standard statistical measures along

  13. Annual Statistical Supplement, 2004

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2004 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  14. 100 statistical tests

    CERN Document Server

    Kanji, Gopal K

    2006-01-01

    This expanded and updated Third Edition of Gopal K. Kanji's best-selling resource on statistical tests covers all the most commonly used tests with information on how to calculate and interpret results with simple datasets. Each entry begins with a short summary statement about the test's purpose, and contains details of the test objective, the limitations (or assumptions) involved, a brief outline of the method, a worked example, and the numerical calculation. 100 Statistical Tests, Third Edition is the one indispensable guide for users of statistical materials and consumers of statistical information at all levels and across all disciplines.

  15. Understanding Computational Bayesian Statistics

    CERN Document Server

    Bolstad, William M

    2011-01-01

    A hands-on introduction to computational statistics from a Bayesian point of view Providing a solid grounding in statistics while uniquely covering the topics from a Bayesian perspective, Understanding Computational Bayesian Statistics successfully guides readers through this new, cutting-edge approach. With its hands-on treatment of the topic, the book shows how samples can be drawn from the posterior distribution when the formula giving its shape is all that is known, and how Bayesian inferences can be based on these samples from the posterior. These ideas are illustrated on common statistic

  16. Record Statistics and Dynamics

    DEFF Research Database (Denmark)

    Sibani, Paolo; Jensen, Henrik J.

    2009-01-01

    The term record statistics covers the statistical properties of records within an ordered series of numerical data obtained from observations or measurements. A record within such series is simply a value larger (or smaller) than all preceding values. The mathematical properties of records strongly...... fluctuations of e. g. the energy are able to push the system past some sort of ‘edge of stability’, inducing irreversible configurational changes, whose statistics then closely follows the statistics of record fluctuations....

  17. Principles of statistics

    CERN Document Server

    Bulmer, M G

    1979-01-01

    There are many textbooks which describe current methods of statistical analysis, while neglecting related theory. There are equally many advanced textbooks which delve into the far reaches of statistical theory, while bypassing practical applications. But between these two approaches is an unfilled gap, in which theory and practice merge at an intermediate level. Professor M. G. Bulmer's Principles of Statistics, originally published in 1965, was created to fill that need. The new, corrected Dover edition of Principles of Statistics makes this invaluable mid-level text available once again fo

  18. Annual Statistical Supplement, 2014

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2014 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  19. Annual Statistical Supplement, 2009

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2009 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  20. Annual Statistical Supplement, 2011

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2011 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  1. Isotonic Glycerol and Sodium Hyaluronate Containing Artificial Tear Decreases Conjunctivochalasis after One and Three Months: A Self-Controlled, Unmasked Study

    Science.gov (United States)

    Kiss, Huba J.; Németh, János

    2015-01-01

    Dry eye complaints are ranked as the most frequent symptoms of patients visiting ophthalmologists. Conjunctivochalasis is a common dry eye disorder, which can cause an unstable tear film and ocular discomfort. The severe conjunctivochalasis characterized by high LId-Parallel COnjunctival Folds (LIPCOF) degree usually requires surgical intervention, where a conservative therapy would be highly desirable. Here we examined the efficacy of a preservative-free, inorganic salt-free unit-dose artificial tear, called Conheal containing isotonic glycerol and 0.015% sodium hyaluronate in a prospective, unmasked, self-controlled study involving 20 patients. The regular use of the glycerol/hyaluronate artificial tear in three months caused a significant improvement in the recorded parameters. Conjunctivochalasis decreased from a mean LIPCOF degree of 2.9±0.4 on both eyes to 1.4±0.6 on the right (median decrease of -2 points, 95% CI from -2.0 to -1.0), and to 1.4±0.7 on the left eye (median decrease of -1 points, 95% CI from -2.0 to -1.0) (p<0.001 for both sides). The tear film breakup time (TFBUT) lengthened from 4.8±1.9 seconds on both eyes to 5.9±2.3 seconds (mean increase of 1.1 seconds, 95% CI from 0.2 to 2.0) and 5.7±1.8 seconds (mean increase of 0.9 seconds, 95% CI from 0.3 to 1.5) on the right and left eyes, respectively (pright eyes = 0.020, pleft eyes = 0.004). The corneal lissamine staining (Oxford Scheme grade) was reduced from 1.3±0.6 on the right and 1.4±0.6 on the left eye significantly (p<0.001) to 0.3±0.4 and 0.2±0.4 on the right and the left eyes. The Ocular Surface Disease Index (OSDI) questionnaire score indicating the subjective complaints of the patients also decreased from a mean value of 36.2±25.3 to 15.6±16.7 (p<0.001). In this study, the artificial tear, Conheal decreased the grade of the conjunctivochalasis significantly after one month of regular use already, from the LIPCOF degree 3, considered as indication of conjunctival surgery, to a

  2. A flexibly shaped spatial scan statistic for detecting clusters

    Directory of Open Access Journals (Sweden)

    Takahashi Kunihiko

    2005-05-01

    Full Text Available Abstract Background The spatial scan statistic proposed by Kulldorff has been applied to a wide variety of epidemiological studies for cluster detection. This scan statistic, however, uses a circular window to define the potential cluster areas and thus has difficulty in correctly detecting actual noncircular clusters. A recent proposal by Duczmal and Assunção for detecting noncircular clusters is shown to detect a cluster of very irregular shape that is much larger than the true cluster in our experiences. Methods We propose a flexibly shaped spatial scan statistic that can detect irregular shaped clusters within relatively small neighborhoods of each region. The performance of the proposed spatial scan statistic is compared to that of Kulldorff's circular spatial scan statistic with Monte Carlo simulation by considering several circular and noncircular hot-spot cluster models. For comparison, we also propose a new bivariate power distribution classified by the number of regions detected as the most likely cluster and the number of hot-spot regions included in the most likely cluster. Results The circular spatial scan statistics shows a high level of accuracy in detecting circular clusters exactly. The proposed spatial scan statistic is shown to have good usual powers plus the ability to detect the noncircular hot-spot clusters more accurately than the circular one. Conclusion The proposed spatial scan statistic is shown to work well for small to moderate cluster size, up to say 30. For larger cluster sizes, the method is not practically feasible and a more efficient algorithm is needed.

  3. Practical statistics for educators

    CERN Document Server

    Ravid, Ruth

    2014-01-01

    Practical Statistics for Educators, Fifth Edition, is a clear and easy-to-follow text written specifically for education students in introductory statistics courses and in action research courses. It is also a valuable resource and guidebook for educational practitioners who wish to study their own settings.

  4. Fermi–Dirac Statistics

    Indian Academy of Sciences (India)

    IAS Admin

    Dirac statistics, identical and in- distinguishable particles, Fermi gas. Fermi–Dirac Statistics. Derivation and Consequences. S Chaturvedi and Shyamal Biswas ... GENERAL. ARTICLE. RESONANCE. January 2014. 57. Historically, one of the first applications of. Fermi–Dirac distribution came from Fowler in the context of.

  5. Practical statistics simply explained

    CERN Document Server

    Langley, Dr Russell A

    1971-01-01

    For those who need to know statistics but shy away from math, this book teaches how to extract truth and draw valid conclusions from numerical data using logic and the philosophy of statistics rather than complex formulae. Lucid discussion of averages and scatter, investigation design, more. Problems with solutions.

  6. Thiele. Pioneer in statistics

    DEFF Research Database (Denmark)

    Lauritzen, Steffen Lilholt

    This book studies the brilliant Danish 19th Century astronomer, T.N. Thiele who made important contributions to statistics, actuarial science, astronomy and mathematics. The most important of these contributions in statistics are translated into English for the first time, and the text includes c...

  7. Statistical methods in metabolomics.

    Science.gov (United States)

    Korman, Alexander; Oh, Amy; Raskind, Alexander; Banks, David

    2012-01-01

    Metabolomics is the relatively new field in bioinformatics that uses measurements on metabolite abundance as a tool for disease diagnosis and other medical purposes. Although closely related to proteomics, the statistical analysis is potentially simpler since biochemists have significantly more domain knowledge about metabolites. This chapter reviews the challenges that metabolomics poses in the areas of quality control, statistical metrology, and data mining.

  8. On Statistical Testing.

    Science.gov (United States)

    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…

  9. Applied Statistics with SPSS

    Science.gov (United States)

    Huizingh, Eelko K. R. E.

    2007-01-01

    Accessibly written and easy to use, "Applied Statistics Using SPSS" is an all-in-one self-study guide to SPSS and do-it-yourself guide to statistics. What is unique about Eelko Huizingh's approach is that this book is based around the needs of undergraduate students embarking on their own research project, and its self-help style is designed to…

  10. Handbook of Spatial Statistics

    CERN Document Server

    Gelfand, Alan E

    2010-01-01

    Offers an introduction detailing the evolution of the field of spatial statistics. This title focuses on the three main branches of spatial statistics: continuous spatial variation (point referenced data); discrete spatial variation, including lattice and areal unit data; and, spatial point patterns.

  11. Thiele. Pioneer in statistics

    DEFF Research Database (Denmark)

    Lauritzen, Steffen Lilholt

    This book studies the brilliant Danish 19th Century astronomer, T.N. Thiele who made important contributions to statistics, actuarial science, astronomy and mathematics. The most important of these contributions in statistics are translated into English for the first time, and the text includes...

  12. Enhancing statistical literacy

    NARCIS (Netherlands)

    Droogers, M.J.S.|info:eu-repo/dai/nl/413392252; Drijvers, P.H.M.|info:eu-repo/dai/nl/074302922

    2017-01-01

    Current secondary school statistics curricula focus on procedural knowledge and pay too little attention to statistical reasoning. As a result, students are not able to apply their knowledge to practice. In addition, education often targets the average student, which may lead to gifted students

  13. Fisher's Contributions to Statistics

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 9. Fisher's Contributions to Statistics. T Krishnan. General Article Volume 2 Issue 9 September 1997 pp 32-37 ... Author Affiliations. T Krishnan1. Computer Science Unit, Indian Statistical Institute, 203 B T Road, Calcutta 700 035, India ...

  14. Reform in Statistical Education

    Science.gov (United States)

    Huck, Schuyler W.

    2007-01-01

    Two questions are considered in this article: (a) What should professionals in school psychology do in an effort to stay current with developments in applied statistics? (b) What should they do with their existing knowledge to move from surface understanding of statistics to deep understanding? Written for school psychologists who have completed…

  15. Understanding advanced statistical methods

    CERN Document Server

    Westfall, Peter

    2013-01-01

    Introduction: Probability, Statistics, and ScienceReality, Nature, Science, and ModelsStatistical Processes: Nature, Design and Measurement, and DataModelsDeterministic ModelsVariabilityParametersPurely Probabilistic Statistical ModelsStatistical Models with Both Deterministic and Probabilistic ComponentsStatistical InferenceGood and Bad ModelsUses of Probability ModelsRandom Variables and Their Probability DistributionsIntroductionTypes of Random Variables: Nominal, Ordinal, and ContinuousDiscrete Probability Distribution FunctionsContinuous Probability Distribution FunctionsSome Calculus-Derivatives and Least SquaresMore Calculus-Integrals and Cumulative Distribution FunctionsProbability Calculation and SimulationIntroductionAnalytic Calculations, Discrete and Continuous CasesSimulation-Based ApproximationGenerating Random NumbersIdentifying DistributionsIntroductionIdentifying Distributions from Theory AloneUsing Data: Estimating Distributions via the HistogramQuantiles: Theoretical and Data-Based Estimate...

  16. Introduction to Bayesian statistics

    CERN Document Server

    Bolstad, William M

    2017-01-01

    There is a strong upsurge in the use of Bayesian methods in applied statistical analysis, yet most introductory statistics texts only present frequentist methods. Bayesian statistics has many important advantages that students should learn about if they are going into fields where statistics will be used. In this Third Edition, four newly-added chapters address topics that reflect the rapid advances in the field of Bayesian staistics. The author continues to provide a Bayesian treatment of introductory statistical topics, such as scientific data gathering, discrete random variables, robust Bayesian methods, and Bayesian approaches to inferenfe cfor discrete random variables, bionomial proprotion, Poisson, normal mean, and simple linear regression. In addition, newly-developing topics in the field are presented in four new chapters: Bayesian inference with unknown mean and variance; Bayesian inference for Multivariate Normal mean vector; Bayesian inference for Multiple Linear RegressionModel; and Computati...

  17. The accuracy of cell-free fetal DNA-based non-invasive prenatal testing in singleton pregnancies: a systematic review and bivariate meta-analysis.

    Science.gov (United States)

    Mackie, F L; Hemming, K; Allen, S; Morris, R K; Kilby, M D

    2017-01-01

    Cell-free fetal DNA (cffDNA) non-invasive prenatal testing (NIPT) is rapidly expanding, and is being introduced at varying rates depending on country and condition. Determine accuracy of cffDNA-based NIPT for all conditions. Evaluate influence of other factors on test performance. Medline, Embase, CINAHL, Cochrane Library, from 1997 to April 2015. Cohort studies reporting cffDNA-based NIPT performance in singleton pregnancies. Bivariate or univariate meta-analysis and subgroup analysis performed to explore influence of test type and population risk. A total of 117 studies were included that analysed 18 conditions. Bivariate meta-analysis demonstrated sensitivities and specificities, respectively, for: fetal sex, 0.989 (95% CI 0.980-0.994) and 0.996 (95% CI 0.989-0.998), 11 179 tests; rhesus D, 0.993 (95% CI 0.982-0.997) and 0.984 (95% CI 0.964-0.993), 10 290 tests; trisomy 21, 0.994 (95% CI 0.983-0.998) and 0.999 (95% CI 0.999-1.000), 148 344 tests; trisomy 18, 0.977 (95% CI 0.952-0.989) and 0.999 (95% CI 0.998-1.000), 146 940 tests; monosomy X, 0.929 (95% CI 0.741-0.984) and 0.999 (95% CI 0.995-0.999), 6712 tests. Trisomy 13 was analysed by univariate meta-analysis, with a summary sensitivity of 0.906 (95% CI 0.823-0.958) and specificity of 1.00 (95% CI 0.999-0.100), from 134 691 tests. False and inconclusive results were poorly reported across all conditions. Although the test type affected both sensitivity and specificity, there was no evidence that population risk had any effect. Performance of cffDNA-based NIPT is affected by condition under investigation. For fetal sex and rhesus D status, NIPT can be considered diagnostic. For trisomy 21, 18, and 13, the lower sensitivity, specificity, and disease prevalence, combined with the biological influence of confined placental mosaicism, designates it a screening test. These factors must be considered when counselling patients and assessing the cost of introduction into routine care

  18. Statistical physics; Physique statistique

    Energy Technology Data Exchange (ETDEWEB)

    Couture, L.; Zitoun, R. [Universite Pierre et Marie Curie, 75 - Paris (France)

    1992-12-31

    The basis of statistical physics is exposed. The statistical models of Maxwell-Boltzmann, of Bose-Einstein and of Fermi-Dirac and their particular application fields are presented. The statistical theory is applied in different ranges of physics: gas characteristics, paramagnetism, crystal thermal properties and solid electronic properties. A whole chapter is dedicated to helium and its characteristics such as superfluidity, another deals with superconductivity. Superconductivity is presented both experimentally and theoretically. Meissner effect and Josephson effect are described and the framework of BCS theory is drawn. (A.C.)

  19. Statistical Pattern Recognition

    CERN Document Server

    Webb, Andrew R

    2011-01-01

    Statistical pattern recognition relates to the use of statistical techniques for analysing data measurements in order to extract information and make justified decisions.  It is a very active area of study and research, which has seen many advances in recent years. Applications such as data mining, web searching, multimedia data retrieval, face recognition, and cursive handwriting recognition, all require robust and efficient pattern recognition techniques. This third edition provides an introduction to statistical pattern theory and techniques, with material drawn from a wide range of fields,

  20. Statistics a complete introduction

    CERN Document Server

    Graham, Alan

    2013-01-01

    Statistics: A Complete Introduction is the most comprehensive yet easy-to-use introduction to using Statistics. Written by a leading expert, this book will help you if you are studying for an important exam or essay, or if you simply want to improve your knowledge. The book covers all the key areas of Statistics including graphs, data interpretation, spreadsheets, regression, correlation and probability. Everything you will need is here in this one book. Each chapter includes not only an explanation of the knowledge and skills you need, but also worked examples and test questions.

  1. Statistical deception at work

    CERN Document Server

    Mauro, John

    2013-01-01

    Written to reveal statistical deceptions often thrust upon unsuspecting journalists, this book views the use of numbers from a public perspective. Illustrating how the statistical naivete of journalists often nourishes quantitative misinformation, the author's intent is to make journalists more critical appraisers of numerical data so that in reporting them they do not deceive the public. The book frequently uses actual reported examples of misused statistical data reported by mass media and describes how journalists can avoid being taken in by them. Because reports of survey findings seldom g

  2. Evolutionary Statistical Procedures

    CERN Document Server

    Baragona, Roberto; Poli, Irene

    2011-01-01

    This proposed text appears to be a good introduction to evolutionary computation for use in applied statistics research. The authors draw from a vast base of knowledge about the current literature in both the design of evolutionary algorithms and statistical techniques. Modern statistical research is on the threshold of solving increasingly complex problems in high dimensions, and the generalization of its methodology to parameters whose estimators do not follow mathematically simple distributions is underway. Many of these challenges involve optimizing functions for which analytic solutions a

  3. The nature of statistics

    CERN Document Server

    Wallis, W Allen

    2014-01-01

    Focusing on everyday applications as well as those of scientific research, this classic of modern statistical methods requires little to no mathematical background. Readers develop basic skills for evaluating and using statistical data. Lively, relevant examples include applications to business, government, social and physical sciences, genetics, medicine, and public health. ""W. Allen Wallis and Harry V. Roberts have made statistics fascinating."" - The New York Times ""The authors have set out with considerable success, to write a text which would be of interest and value to the student who,

  4. Statistical Group Comparison

    CERN Document Server

    Liao, Tim Futing

    2011-01-01

    An incomparably useful examination of statistical methods for comparisonThe nature of doing science, be it natural or social, inevitably calls for comparison. Statistical methods are at the heart of such comparison, for they not only help us gain understanding of the world around us but often define how our research is to be carried out. The need to compare between groups is best exemplified by experiments, which have clearly defined statistical methods. However, true experiments are not always possible. What complicates the matter more is a great deal of diversity in factors that are not inde

  5. AP statistics crash course

    CERN Document Server

    D'Alessio, Michael

    2012-01-01

    AP Statistics Crash Course - Gets You a Higher Advanced Placement Score in Less Time Crash Course is perfect for the time-crunched student, the last-minute studier, or anyone who wants a refresher on the subject. AP Statistics Crash Course gives you: Targeted, Focused Review - Study Only What You Need to Know Crash Course is based on an in-depth analysis of the AP Statistics course description outline and actual Advanced Placement test questions. It covers only the information tested on the exam, so you can make the most of your valuable study time. Our easy-to-read format covers: exploring da

  6. The World of Statistics

    Directory of Open Access Journals (Sweden)

    NIS

    2014-06-01

    Full Text Available The International Workshop New Challenges for Statistical Software – The Use of R in Official Statistics was the second of a series of events dedicated to the use of R Project in Romania and initiated by R-omanian R team. We are pleased to announce that 4th of April is the anniversary or R-omanian R team as an R User Group. One year ago, on 4th of April, was taking place the 1st workshop dedicated to the use of R – Workshop State-of-the-art statistical software commonly used in applied economics.

  7. Informal Statistics Help Desk

    Science.gov (United States)

    Young, M.; Koslovsky, M.; Schaefer, Caroline M.; Feiveson, A. H.

    2017-01-01

    Back by popular demand, the JSC Biostatistics Laboratory and LSAH statisticians are offering an opportunity to discuss your statistical challenges and needs. Take the opportunity to meet the individuals offering expert statistical support to the JSC community. Join us for an informal conversation about any questions you may have encountered with issues of experimental design, analysis, or data visualization. Get answers to common questions about sample size, repeated measures, statistical assumptions, missing data, multiple testing, time-to-event data, and when to trust the results of your analyses.

  8. Cancer Data and Statistics Tools

    Science.gov (United States)

    ... National Cancer Conference Stay Informed Cancer Data and Statistics Tools Recommend on Facebook Tweet Share Compartir United States Cancer Statistics The United States Cancer Statistics (USCS): Incidence and ...

  9. Plague Maps and Statistics

    Science.gov (United States)

    ... and Statistics Recommend on Facebook Tweet Share Compartir Plague in the United States Plague was first introduced ... per year in the United States: 1900-2012. Plague Worldwide Plague epidemics have occurred in Africa, Asia, ...

  10. CDC WONDER: Cancer Statistics

    Data.gov (United States)

    U.S. Department of Health & Human Services — The United States Cancer Statistics (USCS) online databases in WONDER provide cancer incidence and mortality data for the United States for the years since 1999, by...

  11. Information theory and statistics

    CERN Document Server

    Kullback, Solomon

    1968-01-01

    Highly useful text studies logarithmic measures of information and their application to testing statistical hypotheses. Includes numerous worked examples and problems. References. Glossary. Appendix. 1968 2nd, revised edition.

  12. Blood Facts and Statistics

    Science.gov (United States)

    ... Donor Community Learn About Blood Blood Facts and Statistics Blood Types Blood Components What Happens to Donated Blood Blood and Diversity History of Blood Transfusion Iron and Blood Donation Hosting ...

  13. Statistics for Finance

    DEFF Research Database (Denmark)

    Lindström, Erik; Madsen, Henrik; Nielsen, Jan Nygaard

    Statistics for Finance develops students’ professional skills in statistics with applications in finance. Developed from the authors’ courses at the Technical University of Denmark and Lund University, the text bridges the gap between classical, rigorous treatments of financial mathematics...... that rarely connect concepts to data and books on econometrics and time series analysis that do not cover specific problems related to option valuation. The book discusses applications of financial derivatives pertaining to risk assessment and elimination. The authors cover various statistical......, identify interest rate models, value bonds, estimate parameters, and much more. This textbook will help students understand and manage empirical research in financial engineering. It includes examples of how the statistical tools can be used to improve value-at-risk calculations and other issues...

  14. Statistical mechanics of superconductivity

    CERN Document Server

    Kita, Takafumi

    2015-01-01

    This book provides a theoretical, step-by-step comprehensive explanation of superconductivity for undergraduate and graduate students who have completed elementary courses on thermodynamics and quantum mechanics. To this end, it adopts the unique approach of starting with the statistical mechanics of quantum ideal gases and successively adding and clarifying elements and techniques indispensible for understanding it. They include the spin-statistics theorem, second quantization, density matrices, the Bloch–De Dominicis theorem, the variational principle in statistical mechanics, attractive interaction, and bound states. Ample examples of their usage are also provided in terms of topics from advanced statistical mechanics such as two-particle correlations of quantum ideal gases, derivation of the Hartree–Fock equations, and Landau’s Fermi-liquid theory, among others. With these preliminaries, the fundamental mean-field equations of superconductivity are derived with maximum mathematical clarity based on ...

  15. Illinois travel statistics, 2010

    Science.gov (United States)

    2011-01-01

    The 2010 Illinois Travel Statistics publication is assembled to provide detailed traffic : information to the different users of traffic data. While most users of traffic data at this level : of detail are within the Illinois Department of Transporta...

  16. Illinois travel statistics, 2008

    Science.gov (United States)

    2009-01-01

    The 2008 Illinois Travel Statistics publication is assembled to provide detailed traffic : information to the different users of traffic data. While most users of traffic data at this level : of detail are within the Illinois Department of Transporta...

  17. Illinois travel statistics, 2009

    Science.gov (United States)

    2010-01-01

    The 2009 Illinois Travel Statistics publication is assembled to provide detailed traffic : information to the different users of traffic data. While most users of traffic data at this level : of detail are within the Illinois Department of Transporta...

  18. Statistical Measures of Marksmanship

    National Research Council Canada - National Science Library

    Johnson, Richard

    2001-01-01

    .... This report describes objective statistical procedures to measure both rifle marksmanship accuracy, the proximity of an array of shots to the center of mass of a target, and marksmanship precision...

  19. Basics of statistical physics

    CERN Document Server

    Müller-Kirsten, Harald J W

    2013-01-01

    Statistics links microscopic and macroscopic phenomena, and requires for this reason a large number of microscopic elements like atoms. The results are values of maximum probability or of averaging. This introduction to statistical physics concentrates on the basic principles, and attempts to explain these in simple terms supplemented by numerous examples. These basic principles include the difference between classical and quantum statistics, a priori probabilities as related to degeneracies, the vital aspect of indistinguishability as compared with distinguishability in classical physics, the differences between conserved and non-conserved elements, the different ways of counting arrangements in the three statistics (Maxwell-Boltzmann, Fermi-Dirac, Bose-Einstein), the difference between maximization of the number of arrangements of elements, and averaging in the Darwin-Fowler method. Significant applications to solids, radiation and electrons in metals are treated in separate chapters, as well as Bose-Eins...

  20. Information theory and statistics

    CERN Document Server

    Kullback, Solomon

    1997-01-01

    Highly useful text studies logarithmic measures of information and their application to testing statistical hypotheses. Includes numerous worked examples and problems. References. Glossary. Appendix. 1968 2nd, revised edition.

  1. Mental Illness Statistics

    Science.gov (United States)

    ... Post-Traumatic Stress Disorder (PTSD) Schizophrenia Suicide All Statistics Topics: A-Z Agoraphobia Anorexia Nervosa Any Anxiety Disorder Any Mood Disorder Attention-Deficit/Hyperactivity Disorder (ADHD) Autism Spectrum ...

  2. Data and Statistics

    Science.gov (United States)

    ... Websites About Us Information For… Media Policy Makers Data & Statistics Recommend on Facebook Tweet Share Compartir Sickle ... Findings Feature Articles Key Findings: CDC’s Sickle Cell Data Collection Program Data Useful in Describing Patterns of ...

  3. Statistics for Finance

    DEFF Research Database (Denmark)

    Lindström, Erik; Madsen, Henrik; Nielsen, Jan Nygaard

    , identify interest rate models, value bonds, estimate parameters, and much more. This textbook will help students understand and manage empirical research in financial engineering. It includes examples of how the statistical tools can be used to improve value-at-risk calculations and other issues......Statistics for Finance develops students’ professional skills in statistics with applications in finance. Developed from the authors’ courses at the Technical University of Denmark and Lund University, the text bridges the gap between classical, rigorous treatments of financial mathematics...... that rarely connect concepts to data and books on econometrics and time series analysis that do not cover specific problems related to option valuation. The book discusses applications of financial derivatives pertaining to risk assessment and elimination. The authors cover various statistical...

  4. Transport statistics 1996

    CSIR Research Space (South Africa)

    Shepperson, L

    1997-12-01

    Full Text Available This publication contains transport and related statistics on roads, vehicles, infrastructure, passengers, freight, rail, air, maritime and road traffic, and international comparisons. The information compiled in this publication has been gathered...

  5. CMS Statistics Reference Booklet

    Data.gov (United States)

    U.S. Department of Health & Human Services — The annual CMS Statistics reference booklet provides a quick reference for summary information about health expenditures and the Medicare and Medicaid health...

  6. EDI Performance Statistics

    Data.gov (United States)

    U.S. Department of Health & Human Services — This section contains statistical information and reports related to the percentage of electronic transactions being sent to Medicare contractors in the formats...

  7. Statistical theory of heat

    CERN Document Server

    Scheck, Florian

    2016-01-01

    Scheck’s textbook starts with a concise introduction to classical thermodynamics, including geometrical aspects. Then a short introduction to probabilities and statistics lays the basis for the statistical interpretation of thermodynamics. Phase transitions, discrete models and the stability of matter are explained in great detail. Thermodynamics has a special role in theoretical physics. Due to the general approach of thermodynamics the field has a bridging function between several areas like the theory of condensed matter, elementary particle physics, astrophysics and cosmology. The classical thermodynamics describes predominantly averaged properties of matter, reaching from few particle systems and state of matter to stellar objects. Statistical Thermodynamics covers the same fields, but explores them in greater depth and unifies classical statistical mechanics with quantum theory of multiple particle systems. The content is presented as two tracks: the fast track for master students, providing the essen...

  8. Titanic: A Statistical Exploration.

    Science.gov (United States)

    Takis, Sandra L.

    1999-01-01

    Uses the available data about the Titanic's passengers to interest students in exploring categorical data and the chi-square distribution. Describes activities incorporated into a statistics class and gives additional resources for collecting information about the Titanic. (ASK)

  9. Heroin: Statistics and Trends

    Science.gov (United States)

    ... Science Adolescent Brain Comorbidity College-Age & Young Adults Criminal Justice Drugged Driving Drug Testing Drugs and the ... opioid overdose Statistics and Trends Swipe left or right to scroll. Monitoring the Future Study: Trends in ...

  10. Boating Accident Statistics

    Data.gov (United States)

    Department of Homeland Security — Accident statistics available on the Coast Guard’s website by state, year, and one variable to obtain tables and/or graphs. Data from reports has been loaded for...

  11. Elements of statistical thermodynamics

    CERN Document Server

    Nash, Leonard K

    2006-01-01

    Encompassing essentially all aspects of statistical mechanics that appear in undergraduate texts, this concise, elementary treatment shows how an atomic-molecular perspective yields new insights into macroscopic thermodynamics. 1974 edition.

  12. Statistics for Finance

    DEFF Research Database (Denmark)

    Lindström, Erik; Madsen, Henrik; Nielsen, Jan Nygaard

    that rarely connect concepts to data and books on econometrics and time series analysis that do not cover specific problems related to option valuation. The book discusses applications of financial derivatives pertaining to risk assessment and elimination. The authors cover various statistical......Statistics for Finance develops students’ professional skills in statistics with applications in finance. Developed from the authors’ courses at the Technical University of Denmark and Lund University, the text bridges the gap between classical, rigorous treatments of financial mathematics......, identify interest rate models, value bonds, estimate parameters, and much more. This textbook will help students understand and manage empirical research in financial engineering. It includes examples of how the statistical tools can be used to improve value-at-risk calculations and other issues...

  13. Business statistics I essentials

    CERN Document Server

    Clark, Louise

    2014-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Business Statistics I includes descriptive statistics, introduction to probability, probability distributions, sampling and sampling distributions, interval estimation, and hypothesis t

  14. Understanding descriptive statistics.

    Science.gov (United States)

    Fisher, Murray J; Marshall, Andrea P

    2009-05-01

    There is an increasing expectation that critical care nurses use clinical research when making decisions about patient care. This article is the second in a series which addresses statistics for clinical nursing practice. In this article we provide an introduction to the use of descriptive statistics. Concepts such as levels of measurement, measures of central tendency and dispersion are described and their use in clinical practice is illustrated.

  15. Statistic>

    DEFF Research Database (Denmark)

    Hansen, Flemming Tvede

    2008-01-01

    Co-organizer for and participant at the exhibition: Statistic>Statistic>2-16/3 2008 Museum fur Kunst und Gewerbe, Hamburg 3/4-27/4 2008...

  16. Statistical Engine Knock Control

    DEFF Research Database (Denmark)

    Stotsky, Alexander A.

    2008-01-01

    A new statistical concept of the knock control of a spark ignition automotive engine is proposed . The control aim is associated with the statistical hy pothesis test which compares the threshold value to the average value of the max imal amplitud e of the knock sensor signal at a given freq uency...... which includ es generation of the amplitud e signals, a threshold value d etermination and a knock sound mod el is d eveloped for evaluation of the control concept....

  17. Breakthroughs in statistics

    CERN Document Server

    Johnson, Norman

    This is author-approved bcc: This is the third volume of a collection of seminal papers in the statistical sciences written during the past 110 years. These papers have each had an outstanding influence on the development of statistical theory and practice over the last century. Each paper is preceded by an introduction written by an authority in the field providing background information and assessing its influence. Volume III concerntrates on articles from the 1980's while including some earlier articles not included in Volume I and II. Samuel Kotz is Professor of Statistics in the College of Business and Management at the University of Maryland. Norman L. Johnson is Professor Emeritus of Statistics at the University of North Carolina. Also available: Breakthroughs in Statistics Volume I: Foundations and Basic Theory Samuel Kotz and Norman L. Johnson, Editors 1993. 631 pp. Softcover. ISBN 0-387-94037-5 Breakthroughs in Statistics Volume II: Methodology and Distribution Samuel Kotz and Norman L. Johnson, Edi...

  18. Measuring dispersed spot of positioning CMOS camera from star image quantitative interpretation based on a bivariate-error least squares curve fitting algorithm

    Science.gov (United States)

    Bu, Fan; Qiu, Yuehong; Yao, Dalei; Yan, Xingtao

    2017-02-01

    For a positioning CMOS camera, we put forward a system which can measure quantitatively dispersed spot parameters and the degree of energy concentration of certain optical system. Based on this method, the detection capability of the positioning CMOS camera can be verified. The measuring method contains some key instruments, such as 550mm collimator, 0.2mm star point, turntable and a positioning CMOS camera. Firstly, the definition of dispersed spot parameters is introduced. Then, the steps of measuring dispersed spot parameters are listed. The energy center of dispersed spot is calculated using centroid algorithm, and then a bivariate-error least squares curve Gaussian fitting method is presented to fit dispersion spot energy distribution curve. Finally, the connected region shaped by the energy contour of the defocused spots is analyzed. The diameter equal to the area which is 80% of the total energy of defocused spots and the energy percentage to the 3×3 central area of the image size are both calculated. The experimental results show that 80% of the total energy of defocused spots is concentrated in the diameter of the inner circle of 15μm, and the percentage to the 3×3 pixels central area can achieve 80% and even higher. Therefore, the method meets the needs of the optical systems in positioning CMOS camera for the imaging quality control.

  19. Modelling the vicious circle between obesity and physical activity in children and adolescents using a bivariate probit model with endogenous regressors.

    Science.gov (United States)

    Yeh, C-Y; Chen, L-J; Ku, P-W; Chen, C-M

    2015-01-01

    The increasing prevalence of obesity in children and adolescents has become one of the most important public health issues around the world. Lack of physical activity is a risk factor for obesity, while being obese could reduce the likelihood of participating in physical activity. Failing to account for the endogeneity between obesity and physical activity would result in biased estimation. This study investigates the relationship between overweight and physical activity by taking endogeneity into consideration. It develops an endogenous bivariate probit model estimated by the maximum likelihood method. The data included 4008 boys and 4197 girls in the 5th-9th grades in Taiwan in 2007-2008. The relationship between overweight and physical activity is significantly negative in the endogenous model, but insignificant in the comparative exogenous model. This endogenous relationship presents a vicious circle in which lower levels of physical activity lead to overweight, while those who are already overweight engage in less physical activity. The results not only reveal the importance of endogenous treatment, but also demonstrate the robust negative relationship between these two factors. An emphasis should be put on overweight and obese children and adolescents in order to break the vicious circle. Promotion of physical activity by appropriate counselling programmes and peer support could be effective in reducing the prevalence of obesity in children and adolescents.

  20. Regional Analysis of Precipitation by Means of Bivariate Distribution Adjusted by Maximum Entropy; Analisis regional de precipitacion con base en una distribucion bivariada ajustada por maxima entropia

    Energy Technology Data Exchange (ETDEWEB)

    Escalante Sandoval, Carlos A.; Dominguez Esquivel, Jose Y. [Universidad Nacional Autonoma de Mexico (Mexico)

    2001-09-01

    The principle of maximum entropy (POME) is used to derive an alternative method of parameter estimation for the bivariate Gumbel distribution. A simple algorithm for this parameter estimation technique is presented. This method is applied to analyze the precipitation in a region of Mexico. Design events are compered with those obtained by the maximum likelihood procedure. According to the results, the proposed technique is a suitable option to be considered when performing frequency analysis of precipitation with small samples. [Spanish] El principio de maxima entropia, conocido como POME, es utilizado para derivar un procedimiento alternativo de estimacion de parametros de la distribucion bivariada de valores extremos con marginales Gumbel. El modelo se aplica al analisis de la precipitacion maxima en 24 horas en una region de Mexico y los eventos de diseno obtenidos son comparados con los proporcionados por la tecnica de maxima verosimilitud. De acuerdo con los resultados obtenidos, se concluye que la tecnica propuesta representa una buena opcion, sobre todo para el caso de muestras pequenas.

  1. Evaluation of Factors Affecting E-Bike Involved Crash and E-Bike License Plate Use in China Using a Bivariate Probit Model

    Directory of Open Access Journals (Sweden)

    Yanyong Guo

    2017-01-01

    Full Text Available The primary objective of this study is to evaluate factors affecting e-bike involved crash and license plate use in China. E-bike crashes data were collected from police database and completed through a telephone interview. Noncrash samples were collected by a questionnaire survey. A bivariate probit (BP model was developed to simultaneously examine the significant factors associated with e-bike involved crash and e-bike license plate and to account for the correlations between them. Marginal effects for contributory factors were calculated to quantify their impacts on the outcomes. The results show that several contributory factors, including gender, age, education level, driver license, car in household, experiences in using e-bike, law compliance, and aggressive driving behaviors, are found to have significant impacts on both e-bike involved crash and license plate use. Moreover, type of e-bike, frequency of using e-bike, impulse behavior, degree of riding experience, and risk perception scale are found to be associated with e-bike involved crash. It is also found that e-bike involved crash and e-bike license plate use are strongly correlated and are negative in direction. The result enhanced our comprehension of the factors related to e-bike involved crash and e-bike license plate use.

  2. Association of Supply Type with Fecal Contamination of Source Water and Household Stored Drinking Water in Developing Countries: A Bivariate Meta-analysis.

    Science.gov (United States)

    Shields, Katherine F; Bain, Robert E S; Cronk, Ryan; Wright, Jim A; Bartram, Jamie

    2015-12-01

    Access to safe drinking water is essential for health. Monitoring access to drinking water focuses on water supply type at the source, but there is limited evidence on whether quality differences at the source persist in water stored in the household. We assessed the extent of fecal contamination at the source and in household stored water (HSW) and explored the relationship between contamination at each sampling point and water supply type. We performed a bivariate random-effects meta-analysis of 45 studies, identified through a systematic review, that reported either the proportion of samples free of fecal indicator bacteria and/or individual sample bacteria counts for source and HSW, disaggregated by supply type. Water quality deteriorated substantially between source and stored water. The mean percentage of contaminated samples (noncompliance) at the source was 46% (95% CI: 33, 60%), whereas mean noncompliance in HSW was 75% (95% CI: 64, 84%). Water supply type was significantly associated with noncompliance at the source (p water (OR = 0.2; 95% CI: 0.1, 0.5) and HSW (OR = 0.3; 95% CI: 0.2, 0.8) from piped supplies had significantly lower odds of contamination compared with non-piped water, potentially due to residual chlorine. Piped water is less likely to be contaminated compared with other water supply types at both the source and in HSW. A focus on upgrading water services to piped supplies may help improve safety, including for those drinking stored water.

  3. Measurement of transition quadrupole moments of high-spin states in the N=74 isotones sup 1 sup 3 sup 3 Pr, sup 1 sup 3 sup 2 Ce and sup 1 sup 3 sup 1 La

    CERN Document Server

    Paul, E S; Gizon, J; Hauschild, K; Hibbert, I M; Joss, D T; Nolan, P J; Nyakó, B M; Sampson, J A; Semple, A T; Wadsworth, R; Walker, L; Wilson, J N; Zolnai, L

    2001-01-01

    The Doppler-Shift Attenuation Method has been used to extract transition quadrupole moments of high-spin bands in the N=74 isotones sup 1 sup 3 sup 3 Pr, sup 1 sup 3 sup 2 Ce and sup 1 sup 3 sup 1 La, produced in the sup 3 sup 7 Cl + sup 1 sup 0 sup 0 Mo reaction. The results appear to be configuration dependent and, for sup 1 sup 3 sup 3 Pr and sup 1 sup 3 sup 2 Ce, the involvement of OMEGA=1/2 nu h sub 9 sub / sub 2 and nu f sub 7 sub / sub 2 intruder orbitals appears to enhance the collectivity at high spin (I>25 Planck constant).

  4. UN Data: Environment Statistics: Waste

    Data.gov (United States)

    World Wide Human Geography Data Working Group — The Environment Statistics Database contains selected water and waste statistics by country. Statistics on water and waste are based on official statistics supplied...

  5. UN Data- Environmental Statistics: Waste

    Data.gov (United States)

    World Wide Human Geography Data Working Group — The Environment Statistics Database contains selected water and waste statistics by country. Statistics on water and waste are based on official statistics supplied...

  6. Predicting radiotherapy outcomes using statistical learning techniques

    Energy Technology Data Exchange (ETDEWEB)

    El Naqa, Issam; Bradley, Jeffrey D; Deasy, Joseph O [Washington University, Saint Louis, MO (United States); Lindsay, Patricia E; Hope, Andrew J [Department of Radiation Oncology, Princess Margaret Hospital, Toronto, ON (Canada)

    2009-09-21

    Radiotherapy outcomes are determined by complex interactions between treatment, anatomical and patient-related variables. A common obstacle to building maximally predictive outcome models for clinical practice is the failure to capture potential complexity of heterogeneous variable interactions and applicability beyond institutional data. We describe a statistical learning methodology that can automatically screen for nonlinear relations among prognostic variables and generalize to unseen data before. In this work, several types of linear and nonlinear kernels to generate interaction terms and approximate the treatment-response function are evaluated. Examples of institutional datasets of esophagitis, pneumonitis and xerostomia endpoints were used. Furthermore, an independent RTOG dataset was used for 'generalizabilty' validation. We formulated the discrimination between risk groups as a supervised learning problem. The distribution of patient groups was initially analyzed using principle components analysis (PCA) to uncover potential nonlinear behavior. The performance of the different methods was evaluated using bivariate correlations and actuarial analysis. Over-fitting was controlled via cross-validation resampling. Our results suggest that a modified support vector machine (SVM) kernel method provided superior performance on leave-one-out testing compared to logistic regression and neural networks in cases where the data exhibited nonlinear behavior on PCA. For instance, in prediction of esophagitis and pneumonitis endpoints, which exhibited nonlinear behavior on PCA, the method provided 21% and 60% improvements, respectively. Furthermore, evaluation on the independent pneumonitis RTOG dataset demonstrated good generalizabilty beyond institutional data in contrast with other models. This indicates that the prediction of treatment response can be improved by utilizing nonlinear kernel methods for discovering important nonlinear interactions among

  7. Predicting radiotherapy outcomes using statistical learning techniques

    Science.gov (United States)

    El Naqa, Issam; Bradley, Jeffrey D.; Lindsay, Patricia E.; Hope, Andrew J.; Deasy, Joseph O.

    2009-09-01

    Radiotherapy outcomes are determined by complex interactions between treatment, anatomical and patient-related variables. A common obstacle to building maximally predictive outcome models for clinical practice is the failure to capture potential complexity of heterogeneous variable interactions and applicability beyond institutional data. We describe a statistical learning methodology that can automatically screen for nonlinear relations among prognostic variables and generalize to unseen data before. In this work, several types of linear and nonlinear kernels to generate interaction terms and approximate the treatment-response function are evaluated. Examples of institutional datasets of esophagitis, pneumonitis and xerostomia endpoints were used. Furthermore, an independent RTOG dataset was used for 'generalizabilty' validation. We formulated the discrimination between risk groups as a supervised learning problem. The distribution of patient groups was initially analyzed using principle components analysis (PCA) to uncover potential nonlinear behavior. The performance of the different methods was evaluated using bivariate correlations and actuarial analysis. Over-fitting was controlled via cross-validation resampling. Our results suggest that a modified support vector machine (SVM) kernel method provided superior performance on leave-one-out testing compared to logistic regression and neural networks in cases where the data exhibited nonlinear behavior on PCA. For instance, in prediction of esophagitis and pneumonitis endpoints, which exhibited nonlinear behavior on PCA, the method provided 21% and 60% improvements, respectively. Furthermore, evaluation on the independent pneumonitis RTOG dataset demonstrated good generalizabilty beyond institutional data in contrast with other models. This indicates that the prediction of treatment response can be improved by utilizing nonlinear kernel methods for discovering important nonlinear interactions among model

  8. Multivariate Statistical Process Control

    DEFF Research Database (Denmark)

    Kulahci, Murat

    2013-01-01

    As sensor and computer technology continues to improve, it becomes a normal occurrence that we confront with high dimensional data sets. As in many areas of industrial statistics, this brings forth various challenges in statistical process control (SPC) and monitoring for which the aim is to iden......As sensor and computer technology continues to improve, it becomes a normal occurrence that we confront with high dimensional data sets. As in many areas of industrial statistics, this brings forth various challenges in statistical process control (SPC) and monitoring for which the aim...... is to identify “out-of-control” state of a process using control charts in order to reduce the excessive variation caused by so-called assignable causes. In practice, the most common method of monitoring multivariate data is through a statistic akin to the Hotelling’s T2. For high dimensional data with excessive...... amount of cross correlation, practitioners are often recommended to use latent structures methods such as Principal Component Analysis to summarize the data in only a few linear combinations of the original variables that capture most of the variation in the data. Applications of these control charts...

  9. Intuitive introductory statistics

    CERN Document Server

    Wolfe, Douglas A

    2017-01-01

    This textbook is designed to give an engaging introduction to statistics and the art of data analysis. The unique scope includes, but also goes beyond, classical methodology associated with the normal distribution. What if the normal model is not valid for a particular data set? This cutting-edge approach provides the alternatives. It is an introduction to the world and possibilities of statistics that uses exercises, computer analyses, and simulations throughout the core lessons. These elementary statistical methods are intuitive. Counting and ranking features prominently in the text. Nonparametric methods, for instance, are often based on counts and ranks and are very easy to integrate into an introductory course. The ease of computation with advanced calculators and statistical software, both of which factor into this text, allows important techniques to be introduced earlier in the study of statistics. This book's novel scope also includes measuring symmetry with Walsh averages, finding a nonp...

  10. Energy statistics manual

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    Detailed, complete, timely and reliable statistics are essential to monitor the energy situation at a country level as well as at an international level. Energy statistics on supply, trade, stocks, transformation and demand are indeed the basis for any sound energy policy decision. For instance, the market of oil -- which is the largest traded commodity worldwide -- needs to be closely monitored in order for all market players to know at any time what is produced, traded, stocked and consumed and by whom. In view of the role and importance of energy in world development, one would expect that basic energy information to be readily available and reliable. This is not always the case and one can even observe a decline in the quality, coverage and timeliness of energy statistics over the last few years.

  11. Philosophy of statistics

    CERN Document Server

    Forster, Malcolm R

    2011-01-01

    Statisticians and philosophers of science have many common interests but restricted communication with each other. This volume aims to remedy these shortcomings. It provides state-of-the-art research in the area of philosophy of statistics by encouraging numerous experts to communicate with one another without feeling "restricted” by their disciplines or thinking "piecemeal” in their treatment of issues. A second goal of this book is to present work in the field without bias toward any particular statistical paradigm. Broadly speaking, the essays in this Handbook are concerned with problems of induction, statistics and probability. For centuries, foundational problems like induction have been among philosophers' favorite topics; recently, however, non-philosophers have increasingly taken a keen interest in these issues. This volume accordingly contains papers by both philosophers and non-philosophers, including scholars from nine academic disciplines.

  12. Probability and Bayesian statistics

    CERN Document Server

    1987-01-01

    This book contains selected and refereed contributions to the "Inter­ national Symposium on Probability and Bayesian Statistics" which was orga­ nized to celebrate the 80th birthday of Professor Bruno de Finetti at his birthplace Innsbruck in Austria. Since Professor de Finetti died in 1985 the symposium was dedicated to the memory of Bruno de Finetti and took place at Igls near Innsbruck from 23 to 26 September 1986. Some of the pa­ pers are published especially by the relationship to Bruno de Finetti's scientific work. The evolution of stochastics shows growing importance of probability as coherent assessment of numerical values as degrees of believe in certain events. This is the basis for Bayesian inference in the sense of modern statistics. The contributions in this volume cover a broad spectrum ranging from foundations of probability across psychological aspects of formulating sub­ jective probability statements, abstract measure theoretical considerations, contributions to theoretical statistics an...

  13. Statistics for Finance

    DEFF Research Database (Denmark)

    Lindström, Erik; Madsen, Henrik; Nielsen, Jan Nygaard

    Statistics for Finance develops students’ professional skills in statistics with applications in finance. Developed from the authors’ courses at the Technical University of Denmark and Lund University, the text bridges the gap between classical, rigorous treatments of financial mathematics...... that rarely connect concepts to data and books on econometrics and time series analysis that do not cover specific problems related to option valuation. The book discusses applications of financial derivatives pertaining to risk assessment and elimination. The authors cover various statistical...... and mathematical techniques, including linear and nonlinear time series analysis, stochastic calculus models, stochastic differential equations, Itō’s formula, the Black–Scholes model, the generalized method-of-moments, and the Kalman filter. They explain how these tools are used to price financial derivatives...

  14. Per Object statistical analysis

    DEFF Research Database (Denmark)

    2008-01-01

    This RS code is to do Object-by-Object analysis of each Object's sub-objects, e.g. statistical analysis of an object's individual image data pixels. Statistics, such as percentiles (so-called "quartiles") are derived by the process, but the return of that can only be a Scene Variable, not an Object...... an analysis of the values of the object's pixels in MS-Excel. The shell of the proceedure could also be used for purposes other than just the derivation of Object - Sub-object statistics, e.g. rule-based assigment processes....... Variable. This procedure was developed in order to be able to export objects as ESRI shape data with the 90-percentile of the Hue of each object's pixels as an item in the shape attribute table. This procedure uses a sub-level single pixel chessboard segmentation, loops for each of the objects...

  15. Perception in statistical graphics

    Science.gov (United States)

    VanderPlas, Susan Ruth

    There has been quite a bit of research on statistical graphics and visualization, generally focused on new types of graphics, new software to create graphics, interactivity, and usability studies. Our ability to interpret and use statistical graphics hinges on the interface between the graph itself and the brain that perceives and interprets it, and there is substantially less research on the interplay between graph, eye, brain, and mind than is sufficient to understand the nature of these relationships. The goal of the work presented here is to further explore the interplay between a static graph, the translation of that graph from paper to mental representation (the journey from eye to brain), and the mental processes that operate on that graph once it is transferred into memory (mind). Understanding the perception of statistical graphics should allow researchers to create more effective graphs which produce fewer distortions and viewer errors while reducing the cognitive load necessary to understand the information presented in the graph. Taken together, these experiments should lay a foundation for exploring the perception of statistical graphics. There has been considerable research into the accuracy of numerical judgments viewers make from graphs, and these studies are useful, but it is more effective to understand how errors in these judgments occur so that the root cause of the error can be addressed directly. Understanding how visual reasoning relates to the ability to make judgments from graphs allows us to tailor graphics to particular target audiences. In addition, understanding the hierarchy of salient features in statistical graphics allows us to clearly communicate the important message from data or statistical models by constructing graphics which are designed specifically for the perceptual system.

  16. Computational statistical mechanics

    CERN Document Server

    Hoover, WG

    1991-01-01

    Computational Statistical Mechanics describes the use of fast computers to simulate the equilibrium and nonequilibrium properties of gases, liquids, and solids at, and away from equilibrium. The underlying theory is developed from basic principles and illustrated by applying it to the simplest possible examples. Thermodynamics, based on the ideal gas thermometer, is related to Gibb's statistical mechanics through the use of Nosé-Hoover heat reservoirs. These reservoirs use integral feedback to control temperature. The same approach is carried through to the simulation and anal

  17. Statistics II essentials

    CERN Document Server

    Milewski, Emil G

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Statistics II discusses sampling theory, statistical inference, independent and dependent variables, correlation theory, experimental design, count data, chi-square test, and time se

  18. Statistics As Principled Argument

    CERN Document Server

    Abelson, Robert P

    2012-01-01

    In this illuminating volume, Robert P. Abelson delves into the too-often dismissed problems of interpreting quantitative data and then presenting them in the context of a coherent story about one's research. Unlike too many books on statistics, this is a remarkably engaging read, filled with fascinating real-life (and real-research) examples rather than with recipes for analysis. It will be of true interest and lasting value to beginning graduate students and seasoned researchers alike. The focus of the book is that the purpose of statistics is to organize a useful argument from quantitative

  19. Elementary Statistics Tables

    CERN Document Server

    Neave, Henry R

    2012-01-01

    This book, designed for students taking a basic introductory course in statistical analysis, is far more than just a book of tables. Each table is accompanied by a careful but concise explanation and useful worked examples. Requiring little mathematical background, Elementary Statistics Tables is thus not just a reference book but a positive and user-friendly teaching and learning aid. The new edition contains a new and comprehensive "teach-yourself" section on a simple but powerful approach, now well-known in parts of industry but less so in academia, to analysing and interpreting process dat

  20. Bayesian statistics an introduction

    CERN Document Server

    Lee, Peter M

    2012-01-01

    Bayesian Statistics is the school of thought that combines prior beliefs with the likelihood of a hypothesis to arrive at posterior beliefs. The first edition of Peter Lee’s book appeared in 1989, but the subject has moved ever onwards, with increasing emphasis on Monte Carlo based techniques. This new fourth edition looks at recent techniques such as variational methods, Bayesian importance sampling, approximate Bayesian computation and Reversible Jump Markov Chain Monte Carlo (RJMCMC), providing a concise account of the way in which the Bayesian approach to statistics develops as wel