WorldWideScience

Sample records for hurdle negative binomial

  1. Censored Hurdle Negative Binomial Regression (Case Study: Neonatorum Tetanus Case in Indonesia)

    Science.gov (United States)

    Yuli Rusdiana, Riza; Zain, Ismaini; Wulan Purnami, Santi

    2017-06-01

    Hurdle negative binomial model regression is a method that can be used for discreate dependent variable, excess zero and under- and overdispersion. It uses two parts approach. The first part estimates zero elements from dependent variable is zero hurdle model and the second part estimates not zero elements (non-negative integer) from dependent variable is called truncated negative binomial models. The discrete dependent variable in such cases is censored for some values. The type of censor that will be studied in this research is right censored. This study aims to obtain the parameter estimator hurdle negative binomial regression for right censored dependent variable. In the assessment of parameter estimation methods used Maximum Likelihood Estimator (MLE). Hurdle negative binomial model regression for right censored dependent variable is applied on the number of neonatorum tetanus cases in Indonesia. The type data is count data which contains zero values in some observations and other variety value. This study also aims to obtain the parameter estimator and test statistic censored hurdle negative binomial model. Based on the regression results, the factors that influence neonatorum tetanus case in Indonesia is the percentage of baby health care coverage and neonatal visits.

  2. Negative binomial multiplicity distribution from binomial cluster production

    International Nuclear Information System (INIS)

    Iso, C.; Mori, K.

    1990-01-01

    Two-step interpretation of negative binomial multiplicity distribution as a compound of binomial cluster production and negative binomial like cluster decay distribution is proposed. In this model we can expect the average multiplicity for the cluster production increases with increasing energy, different from a compound Poisson-Logarithmic distribution. (orig.)

  3. Statistical inference involving binomial and negative binomial parameters.

    Science.gov (United States)

    García-Pérez, Miguel A; Núñez-Antón, Vicente

    2009-05-01

    Statistical inference about two binomial parameters implies that they are both estimated by binomial sampling. There are occasions in which one aims at testing the equality of two binomial parameters before and after the occurrence of the first success along a sequence of Bernoulli trials. In these cases, the binomial parameter before the first success is estimated by negative binomial sampling whereas that after the first success is estimated by binomial sampling, and both estimates are related. This paper derives statistical tools to test two hypotheses, namely, that both binomial parameters equal some specified value and that both parameters are equal though unknown. Simulation studies are used to show that in small samples both tests are accurate in keeping the nominal Type-I error rates, and also to determine sample size requirements to detect large, medium, and small effects with adequate power. Additional simulations also show that the tests are sufficiently robust to certain violations of their assumptions.

  4. Distinguishing between Binomial, Hypergeometric and Negative Binomial Distributions

    Science.gov (United States)

    Wroughton, Jacqueline; Cole, Tarah

    2013-01-01

    Recognizing the differences between three discrete distributions (Binomial, Hypergeometric and Negative Binomial) can be challenging for students. We present an activity designed to help students differentiate among these distributions. In addition, we present assessment results in the form of pre- and post-tests that were designed to assess the…

  5. Zero-truncated negative binomial - Erlang distribution

    Science.gov (United States)

    Bodhisuwan, Winai; Pudprommarat, Chookait; Bodhisuwan, Rujira; Saothayanun, Luckhana

    2017-11-01

    The zero-truncated negative binomial-Erlang distribution is introduced. It is developed from negative binomial-Erlang distribution. In this work, the probability mass function is derived and some properties are included. The parameters of the zero-truncated negative binomial-Erlang distribution are estimated by using the maximum likelihood estimation. Finally, the proposed distribution is applied to real data, the number of methamphetamine in the Bangkok, Thailand. Based on the results, it shows that the zero-truncated negative binomial-Erlang distribution provided a better fit than the zero-truncated Poisson, zero-truncated negative binomial, zero-truncated generalized negative-binomial and zero-truncated Poisson-Lindley distributions for this data.

  6. Zero inflated negative binomial-Sushila distribution and its application

    Science.gov (United States)

    Yamrubboon, Darika; Thongteeraparp, Ampai; Bodhisuwan, Winai; Jampachaisri, Katechan

    2017-11-01

    A new zero inflated distribution is proposed in this work, namely the zero inflated negative binomial-Sushila distribution. The new distribution which is a mixture of the Bernoulli and negative binomial-Sushila distributions is an alternative distribution for the excessive zero counts and over-dispersion. Some characteristics of the proposed distribution are derived including probability mass function, mean and variance. The parameter estimation of the zero inflated negative binomial-Sushila distribution is also implemented by maximum likelihood method. In application, the proposed distribution can provide a better fit than traditional distributions: zero inflated Poisson and zero inflated negative binomial distributions.

  7. Modeling Tetanus Neonatorum case using the regression of negative binomial and zero-inflated negative binomial

    Science.gov (United States)

    Amaliana, Luthfatul; Sa'adah, Umu; Wayan Surya Wardhani, Ni

    2017-12-01

    Tetanus Neonatorum is an infectious disease that can be prevented by immunization. The number of Tetanus Neonatorum cases in East Java Province is the highest in Indonesia until 2015. Tetanus Neonatorum data contain over dispersion and big enough proportion of zero-inflation. Negative Binomial (NB) regression is an alternative method when over dispersion happens in Poisson regression. However, the data containing over dispersion and zero-inflation are more appropriately analyzed by using Zero-Inflated Negative Binomial (ZINB) regression. The purpose of this study are: (1) to model Tetanus Neonatorum cases in East Java Province with 71.05 percent proportion of zero-inflation by using NB and ZINB regression, (2) to obtain the best model. The result of this study indicates that ZINB is better than NB regression with smaller AIC.

  8. Simulation on Poisson and negative binomial models of count road accident modeling

    Science.gov (United States)

    Sapuan, M. S.; Razali, A. M.; Zamzuri, Z. H.; Ibrahim, K.

    2016-11-01

    Accident count data have often been shown to have overdispersion. On the other hand, the data might contain zero count (excess zeros). The simulation study was conducted to create a scenarios which an accident happen in T-junction with the assumption the dependent variables of generated data follows certain distribution namely Poisson and negative binomial distribution with different sample size of n=30 to n=500. The study objective was accomplished by fitting Poisson regression, negative binomial regression and Hurdle negative binomial model to the simulated data. The model validation was compared and the simulation result shows for each different sample size, not all model fit the data nicely even though the data generated from its own distribution especially when the sample size is larger. Furthermore, the larger sample size indicates that more zeros accident count in the dataset.

  9. Wigner Function of Density Operator for Negative Binomial Distribution

    International Nuclear Information System (INIS)

    Xu Xinglei; Li Hongqi

    2008-01-01

    By using the technique of integration within an ordered product (IWOP) of operator we derive Wigner function of density operator for negative binomial distribution of radiation field in the mixed state case, then we derive the Wigner function of squeezed number state, which yields negative binomial distribution by virtue of the entangled state representation and the entangled Wigner operator

  10. Validity of the negative binomial distribution in particle production

    International Nuclear Information System (INIS)

    Cugnon, J.; Harouna, O.

    1987-01-01

    Some aspects of the clan picture for particle production in nuclear and in high-energy processes are examined. In particular, it is shown that the requirement of having logarithmic distribution for the number of particles within a clan in order to generate a negative binomial should not be taken strictly. Large departures are allowed without distorting too much the negative binomial. The question of the undetected particles is also studied. It is shown that, under reasonable circumstances, the latter do not affect the negative binomial character of the multiplicity distribution

  11. Statistical Inference for a Class of Multivariate Negative Binomial Distributions

    DEFF Research Database (Denmark)

    Rubak, Ege H.; Møller, Jesper; McCullagh, Peter

    This paper considers statistical inference procedures for a class of models for positively correlated count variables called -permanental random fields, and which can be viewed as a family of multivariate negative binomial distributions. Their appealing probabilistic properties have earlier been...

  12. Multifractal structure of multiplicity distributions and negative binomials

    International Nuclear Information System (INIS)

    Malik, S.; Delhi, Univ.

    1997-01-01

    The paper presents experimental results of the multifractal structure analysis in proton-emulsion interactions at 800 GeV. The multiplicity moments have a power law dependence on the mean multiplicity in varying bin sizes of pseudorapidity. The values of generalised dimensions are calculated from the slope value. The multifractal characteristics are also examined in the light of negative binomials. The observed multiplicity moments and those derived from the negative-binomial fits agree well with each other. Also the values of D q , both observed and derived from the negative-binomial fits not only decrease with q typifying multifractality but also agree well each other showing consistency with the negative-binomial form

  13. Negative Binomial Distribution and the multiplicity moments at the LHC

    International Nuclear Information System (INIS)

    Praszalowicz, Michal

    2011-01-01

    In this work we show that the latest LHC data on multiplicity moments C 2 -C 5 are well described by a two-step model in the form of a convolution of the Poisson distribution with energy-dependent source function. For the source function we take Γ Negative Binomial Distribution. No unexpected behavior of Negative Binomial Distribution parameter k is found. We give also predictions for the higher energies of 10 and 14 TeV.

  14. Negative binomial properties and clan structure in multiplicity distributions

    International Nuclear Information System (INIS)

    Giovannini, A.; Van Hove, L.

    1988-01-01

    We review the negative binomial properties measured recently for many multiplicity distributions of high energy hadronic, semi-leptonic reactions in selected rapidity intervals. We analyse them in terms of the ''clan'' structure which can be defined for any negative binomial distribution. By comparing reactions we exhibit a number of regularities for the average number N-bar of clans and the average charged multiplicity (n-bar) c per clan. 22 refs., 6 figs. (author)

  15. Number-Phase Wigner Representation and Entropic Uncertainty Relations for Binomial and Negative Binomial States

    International Nuclear Information System (INIS)

    Amitabh, J.; Vaccaro, J.A.; Hill, K.E.

    1998-01-01

    We study the recently defined number-phase Wigner function S NP (n,θ) for a single-mode field considered to be in binomial and negative binomial states. These states interpolate between Fock and coherent states and coherent and quasi thermal states, respectively, and thus provide a set of states with properties ranging from uncertain phase and sharp photon number to sharp phase and uncertain photon number. The distribution function S NP (n,θ) gives a graphical representation of the complimentary nature of the number and phase properties of these states. We highlight important differences between Wigner's quasi probability function, which is associated with the position and momentum observables, and S NP (n,θ), which is associated directly with the photon number and phase observables. We also discuss the number-phase entropic uncertainty relation for the binomial and negative binomial states and we show that negative binomial states give a lower phase entropy than states which minimize the phase variance

  16. Analysis of hypoglycemic events using negative binomial models.

    Science.gov (United States)

    Luo, Junxiang; Qu, Yongming

    2013-01-01

    Negative binomial regression is a standard model to analyze hypoglycemic events in diabetes clinical trials. Adjusting for baseline covariates could potentially increase the estimation efficiency of negative binomial regression. However, adjusting for covariates raises concerns about model misspecification, in which the negative binomial regression is not robust because of its requirement for strong model assumptions. In some literature, it was suggested to correct the standard error of the maximum likelihood estimator through introducing overdispersion, which can be estimated by the Deviance or Pearson Chi-square. We proposed to conduct the negative binomial regression using Sandwich estimation to calculate the covariance matrix of the parameter estimates together with Pearson overdispersion correction (denoted by NBSP). In this research, we compared several commonly used negative binomial model options with our proposed NBSP. Simulations and real data analyses showed that NBSP is the most robust to model misspecification, and the estimation efficiency will be improved by adjusting for baseline hypoglycemia. Copyright © 2013 John Wiley & Sons, Ltd.

  17. Hadronic multiplicity distributions: the negative binomial and its alternatives

    International Nuclear Information System (INIS)

    Carruthers, P.

    1986-01-01

    We review properties of the negative binomial distribution, along with its many possible statistical or dynamical origins. Considering the relation of the multiplicity distribution to the density matrix for Boson systems, we re-introduce the partially coherent laser distribution, which allows for coherent as well as incoherent hadronic emission from the k fundamental cells, and provides equally good phenomenological fits to existing data. The broadening of non-single diffractive hadron-hadron distributions can be equally well due to the decrease of coherent with increasing energy as to the large (and rapidly decreasing) values of k deduced from negative binomial fits. Similarly the narrowness of e + -e - multiplicity distribution is due to nearly coherent (therefore nearly Poissonian) emission from a small number of jets, in contrast to the negative binomial with enormous values of k. 31 refs

  18. Sample size calculation for comparing two negative binomial rates.

    Science.gov (United States)

    Zhu, Haiyuan; Lakkis, Hassan

    2014-02-10

    Negative binomial model has been increasingly used to model the count data in recent clinical trials. It is frequently chosen over Poisson model in cases of overdispersed count data that are commonly seen in clinical trials. One of the challenges of applying negative binomial model in clinical trial design is the sample size estimation. In practice, simulation methods have been frequently used for sample size estimation. In this paper, an explicit formula is developed to calculate sample size based on the negative binomial model. Depending on different approaches to estimate the variance under null hypothesis, three variations of the sample size formula are proposed and discussed. Important characteristics of the formula include its accuracy and its ability to explicitly incorporate dispersion parameter and exposure time. The performance of the formula with each variation is assessed using simulations. Copyright © 2013 John Wiley & Sons, Ltd.

  19. Hadronic multiplicity distributions: the negative binomial and its alternatives

    International Nuclear Information System (INIS)

    Carruthers, P.

    1986-01-01

    We review properties of the negative binomial distribution, along with its many possible statistical or dynamical origins. Considering the relation of the multiplicity distribution to the density matrix for boson systems, we re-introduce the partially coherent laser distribution, which allows for coherent as well as incoherent hadronic emission from the k fundamental cells, and provides equally good phenomenological fits to existing data. The broadening of non-single diffractive hadron-hadron distributions can be equally well due to the decrease of coherence with increasing energy as to the large (and rapidly decreasing) values of k deduced from negative binomial fits. Similarly the narrowness of e + -e - multiplicity distribution is due to nearly coherent (therefore nearly Poissonian) emission from a small number of jets, in contrast to the negative binomial with enormous values of k. 31 refs

  20. Interpretations and implications of negative binomial distributions of multiparticle productions

    International Nuclear Information System (INIS)

    Arisawa, Tetsuo

    2006-01-01

    The number of particles produced in high energy experiments is approximated by a negative binomial distribution. Deriving a representation of the distribution from a stochastic equation, conditions for the process to satisfy the distribution are clarified. Based on them, it is proposed that multiparticle production consists of spontaneous and induced production. The rate of the induced production is proportional to the number of existing particles. The ratio of the two production rates remains constant during the process. The ''NBD space'' is also defined where the number of particles produced in its subspaces follows negative binomial distributions with different parameters

  1. Statistical inference for a class of multivariate negative binomial distributions

    DEFF Research Database (Denmark)

    Rubak, Ege Holger; Møller, Jesper; McCullagh, Peter

    This paper considers statistical inference procedures for a class of models for positively correlated count variables called α-permanental random fields, and which can be viewed as a family of multivariate negative binomial distributions. Their appealing probabilistic properties have earlier been...

  2. Estimating negative binomial parameters from occurrence data with detection times.

    Science.gov (United States)

    Hwang, Wen-Han; Huggins, Richard; Stoklosa, Jakub

    2016-11-01

    The negative binomial distribution is a common model for the analysis of count data in biology and ecology. In many applications, we may not observe the complete frequency count in a quadrat but only that a species occurred in the quadrat. If only occurrence data are available then the two parameters of the negative binomial distribution, the aggregation index and the mean, are not identifiable. This can be overcome by data augmentation or through modeling the dependence between quadrat occupancies. Here, we propose to record the (first) detection time while collecting occurrence data in a quadrat. We show that under what we call proportionate sampling, where the time to survey a region is proportional to the area of the region, that both negative binomial parameters are estimable. When the mean parameter is larger than two, our proposed approach is more efficient than the data augmentation method developed by Solow and Smith (, Am. Nat. 176, 96-98), and in general is cheaper to conduct. We also investigate the effect of misidentification when collecting negative binomially distributed data, and conclude that, in general, the effect can be simply adjusted for provided that the mean and variance of misidentification probabilities are known. The results are demonstrated in a simulation study and illustrated in several real examples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Application of Negative Binomial Regression for Assessing Public ...

    African Journals Online (AJOL)

    Because the variance was nearly two times greater than the mean, the negative binomial regression model provided an improved fit to the data and accounted better for overdispersion than the Poisson regression model, which assumed that the mean and variance are the same. The level of education and race were found

  4. Zero inflated negative binomial-generalized exponential distributionand its applications

    Directory of Open Access Journals (Sweden)

    Sirinapa Aryuyuen

    2014-08-01

    Full Text Available In this paper, we propose a new zero inflated distribution, namely, the zero inflated negative binomial-generalized exponential (ZINB-GE distribution. The new distribution is used for count data with extra zeros and is an alternative for data analysis with over-dispersed count data. Some characteristics of the distribution are given, such as mean, variance, skewness, and kurtosis. Parameter estimation of the ZINB-GE distribution uses maximum likelihood estimation (MLE method. Simulated and observed data are employed to examine this distribution. The results show that the MLE method seems to have high efficiency for large sample sizes. Moreover, the mean square error of parameter estimation is increased when the zero proportion is higher. For the real data sets, this new zero inflated distribution provides a better fit than the zero inflated Poisson and zero inflated negative binomial distributions.

  5. e+-e- hadronic multiplicity distributions: negative binomial or Poisson

    International Nuclear Information System (INIS)

    Carruthers, P.; Shih, C.C.

    1986-01-01

    On the basis of fits to the multiplicity distributions for variable rapidity windows and the forward backward correlation for the 2 jet subset of e + e - data it is impossible to distinguish between a global negative binomial and its generalization, the partially coherent distribution. It is suggested that intensity interferometry, especially the Bose-Einstein correlation, gives information which will discriminate among dynamical models. 16 refs

  6. Confidence Intervals for Asbestos Fiber Counts: Approximate Negative Binomial Distribution.

    Science.gov (United States)

    Bartley, David; Slaven, James; Harper, Martin

    2017-03-01

    The negative binomial distribution is adopted for analyzing asbestos fiber counts so as to account for both the sampling errors in capturing only a finite number of fibers and the inevitable human variation in identifying and counting sampled fibers. A simple approximation to this distribution is developed for the derivation of quantiles and approximate confidence limits. The success of the approximation depends critically on the use of Stirling's expansion to sufficient order, on exact normalization of the approximating distribution, on reasonable perturbation of quantities from the normal distribution, and on accurately approximating sums by inverse-trapezoidal integration. Accuracy of the approximation developed is checked through simulation and also by comparison to traditional approximate confidence intervals in the specific case that the negative binomial distribution approaches the Poisson distribution. The resulting statistics are shown to relate directly to early research into the accuracy of asbestos sampling and analysis. Uncertainty in estimating mean asbestos fiber concentrations given only a single count is derived. Decision limits (limits of detection) and detection limits are considered for controlling false-positive and false-negative detection assertions and are compared to traditional limits computed assuming normal distributions. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2017.

  7. Estimation of adjusted rate differences using additive negative binomial regression.

    Science.gov (United States)

    Donoghoe, Mark W; Marschner, Ian C

    2016-08-15

    Rate differences are an important effect measure in biostatistics and provide an alternative perspective to rate ratios. When the data are event counts observed during an exposure period, adjusted rate differences may be estimated using an identity-link Poisson generalised linear model, also known as additive Poisson regression. A problem with this approach is that the assumption of equality of mean and variance rarely holds in real data, which often show overdispersion. An additive negative binomial model is the natural alternative to account for this; however, standard model-fitting methods are often unable to cope with the constrained parameter space arising from the non-negativity restrictions of the additive model. In this paper, we propose a novel solution to this problem using a variant of the expectation-conditional maximisation-either algorithm. Our method provides a reliable way to fit an additive negative binomial regression model and also permits flexible generalisations using semi-parametric regression functions. We illustrate the method using a placebo-controlled clinical trial of fenofibrate treatment in patients with type II diabetes, where the outcome is the number of laser therapy courses administered to treat diabetic retinopathy. An R package is available that implements the proposed method. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Negative binomial models for abundance estimation of multiple closed populations

    Science.gov (United States)

    Boyce, Mark S.; MacKenzie, Darry I.; Manly, Bryan F.J.; Haroldson, Mark A.; Moody, David W.

    2001-01-01

    Counts of uniquely identified individuals in a population offer opportunities to estimate abundance. However, for various reasons such counts may be burdened by heterogeneity in the probability of being detected. Theoretical arguments and empirical evidence demonstrate that the negative binomial distribution (NBD) is a useful characterization for counts from biological populations with heterogeneity. We propose a method that focuses on estimating multiple populations by simultaneously using a suite of models derived from the NBD. We used this approach to estimate the number of female grizzly bears (Ursus arctos) with cubs-of-the-year in the Yellowstone ecosystem, for each year, 1986-1998. Akaike's Information Criteria (AIC) indicated that a negative binomial model with a constant level of heterogeneity across all years was best for characterizing the sighting frequencies of female grizzly bears. A lack-of-fit test indicated the model adequately described the collected data. Bootstrap techniques were used to estimate standard errors and 95% confidence intervals. We provide a Monte Carlo technique, which confirms that the Yellowstone ecosystem grizzly bear population increased during the period 1986-1998.

  9. Negative binomial mixed models for analyzing microbiome count data.

    Science.gov (United States)

    Zhang, Xinyan; Mallick, Himel; Tang, Zaixiang; Zhang, Lei; Cui, Xiangqin; Benson, Andrew K; Yi, Nengjun

    2017-01-03

    Recent advances in next-generation sequencing (NGS) technology enable researchers to collect a large volume of metagenomic sequencing data. These data provide valuable resources for investigating interactions between the microbiome and host environmental/clinical factors. In addition to the well-known properties of microbiome count measurements, for example, varied total sequence reads across samples, over-dispersion and zero-inflation, microbiome studies usually collect samples with hierarchical structures, which introduce correlation among the samples and thus further complicate the analysis and interpretation of microbiome count data. In this article, we propose negative binomial mixed models (NBMMs) for detecting the association between the microbiome and host environmental/clinical factors for correlated microbiome count data. Although having not dealt with zero-inflation, the proposed mixed-effects models account for correlation among the samples by incorporating random effects into the commonly used fixed-effects negative binomial model, and can efficiently handle over-dispersion and varying total reads. We have developed a flexible and efficient IWLS (Iterative Weighted Least Squares) algorithm to fit the proposed NBMMs by taking advantage of the standard procedure for fitting the linear mixed models. We evaluate and demonstrate the proposed method via extensive simulation studies and the application to mouse gut microbiome data. The results show that the proposed method has desirable properties and outperform the previously used methods in terms of both empirical power and Type I error. The method has been incorporated into the freely available R package BhGLM ( http://www.ssg.uab.edu/bhglm/ and http://github.com/abbyyan3/BhGLM ), providing a useful tool for analyzing microbiome data.

  10. Measured PET Data Characterization with the Negative Binomial Distribution Model.

    Science.gov (United States)

    Santarelli, Maria Filomena; Positano, Vincenzo; Landini, Luigi

    2017-01-01

    Accurate statistical model of PET measurements is a prerequisite for a correct image reconstruction when using statistical image reconstruction algorithms, or when pre-filtering operations must be performed. Although radioactive decay follows a Poisson distribution, deviation from Poisson statistics occurs on projection data prior to reconstruction due to physical effects, measurement errors, correction of scatter and random coincidences. Modelling projection data can aid in understanding the statistical nature of the data in order to develop efficient processing methods and to reduce noise. This paper outlines the statistical behaviour of measured emission data evaluating the goodness of fit of the negative binomial (NB) distribution model to PET data for a wide range of emission activity values. An NB distribution model is characterized by the mean of the data and the dispersion parameter α that describes the deviation from Poisson statistics. Monte Carlo simulations were performed to evaluate: (a) the performances of the dispersion parameter α estimator, (b) the goodness of fit of the NB model for a wide range of activity values. We focused on the effect produced by correction for random and scatter events in the projection (sinogram) domain, due to their importance in quantitative analysis of PET data. The analysis developed herein allowed us to assess the accuracy of the NB distribution model to fit corrected sinogram data, and to evaluate the sensitivity of the dispersion parameter α to quantify deviation from Poisson statistics. By the sinogram ROI-based analysis, it was demonstrated that deviation on the measured data from Poisson statistics can be quantitatively characterized by the dispersion parameter α, in any noise conditions and corrections.

  11. On the revival of the negative binomial distribution in multiparticle production

    International Nuclear Information System (INIS)

    Ekspong, G.

    1990-01-01

    This paper is based on published and some unpublished material pertaining to the revival of interest in and success of applying the negative binomial distribution to multiparticle production since 1983. After a historically oriented introduction going farther back in time, the main part of the paper is devoted to an unpublished derivation of the negative binomial distribution based on empirical observations of forward-backward multiplicity correlations. Some physical processes leading to the negative binomial distribution are mentioned and some comments made on published criticisms

  12. On bounds in Poisson approximation for distributions of independent negative-binomial distributed random variables.

    Science.gov (United States)

    Hung, Tran Loc; Giang, Le Truong

    2016-01-01

    Using the Stein-Chen method some upper bounds in Poisson approximation for distributions of row-wise triangular arrays of independent negative-binomial distributed random variables are established in this note.

  13. Reliability of environmental sampling culture results using the negative binomial intraclass correlation coefficient.

    Science.gov (United States)

    Aly, Sharif S; Zhao, Jianyang; Li, Ben; Jiang, Jiming

    2014-01-01

    The Intraclass Correlation Coefficient (ICC) is commonly used to estimate the similarity between quantitative measures obtained from different sources. Overdispersed data is traditionally transformed so that linear mixed model (LMM) based ICC can be estimated. A common transformation used is the natural logarithm. The reliability of environmental sampling of fecal slurry on freestall pens has been estimated for Mycobacterium avium subsp. paratuberculosis using the natural logarithm transformed culture results. Recently, the negative binomial ICC was defined based on a generalized linear mixed model for negative binomial distributed data. The current study reports on the negative binomial ICC estimate which includes fixed effects using culture results of environmental samples. Simulations using a wide variety of inputs and negative binomial distribution parameters (r; p) showed better performance of the new negative binomial ICC compared to the ICC based on LMM even when negative binomial data was logarithm, and square root transformed. A second comparison that targeted a wider range of ICC values showed that the mean of estimated ICC closely approximated the true ICC.

  14. Analysis of generalized negative binomial distributions attached to hyperbolic Landau levels

    Energy Technology Data Exchange (ETDEWEB)

    Chhaiba, Hassan, E-mail: chhaiba.hassan@gmail.com [Department of Mathematics, Faculty of Sciences, Ibn Tofail University, P.O. Box 133, Kénitra (Morocco); Demni, Nizar, E-mail: nizar.demni@univ-rennes1.fr [IRMAR, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France); Mouayn, Zouhair, E-mail: mouayn@fstbm.ac.ma [Department of Mathematics, Faculty of Sciences and Technics (M’Ghila), Sultan Moulay Slimane, P.O. Box 523, Béni Mellal (Morocco)

    2016-07-15

    To each hyperbolic Landau level of the Poincaré disc is attached a generalized negative binomial distribution. In this paper, we compute the moment generating function of this distribution and supply its atomic decomposition as a perturbation of the negative binomial distribution by a finitely supported measure. Using the Mandel parameter, we also discuss the nonclassical nature of the associated coherent states. Next, we derive a Lévy-Khintchine-type representation of its characteristic function when the latter does not vanish and deduce that it is quasi-infinitely divisible except for the lowest hyperbolic Landau level corresponding to the negative binomial distribution. By considering the total variation of the obtained quasi-Lévy measure, we introduce a new infinitely divisible distribution for which we derive the characteristic function.

  15. Analysis of generalized negative binomial distributions attached to hyperbolic Landau levels

    International Nuclear Information System (INIS)

    Chhaiba, Hassan; Demni, Nizar; Mouayn, Zouhair

    2016-01-01

    To each hyperbolic Landau level of the Poincaré disc is attached a generalized negative binomial distribution. In this paper, we compute the moment generating function of this distribution and supply its atomic decomposition as a perturbation of the negative binomial distribution by a finitely supported measure. Using the Mandel parameter, we also discuss the nonclassical nature of the associated coherent states. Next, we derive a Lévy-Khintchine-type representation of its characteristic function when the latter does not vanish and deduce that it is quasi-infinitely divisible except for the lowest hyperbolic Landau level corresponding to the negative binomial distribution. By considering the total variation of the obtained quasi-Lévy measure, we introduce a new infinitely divisible distribution for which we derive the characteristic function.

  16. Variability in results from negative binomial models for Lyme disease measured at different spatial scales.

    Science.gov (United States)

    Tran, Phoebe; Waller, Lance

    2015-01-01

    Lyme disease has been the subject of many studies due to increasing incidence rates year after year and the severe complications that can arise in later stages of the disease. Negative binomial models have been used to model Lyme disease in the past with some success. However, there has been little focus on the reliability and consistency of these models when they are used to study Lyme disease at multiple spatial scales. This study seeks to explore how sensitive/consistent negative binomial models are when they are used to study Lyme disease at different spatial scales (at the regional and sub-regional levels). The study area includes the thirteen states in the Northeastern United States with the highest Lyme disease incidence during the 2002-2006 period. Lyme disease incidence at county level for the period of 2002-2006 was linked with several previously identified key landscape and climatic variables in a negative binomial regression model for the Northeastern region and two smaller sub-regions (the New England sub-region and the Mid-Atlantic sub-region). This study found that negative binomial models, indeed, were sensitive/inconsistent when used at different spatial scales. We discuss various plausible explanations for such behavior of negative binomial models. Further investigation of the inconsistency and sensitivity of negative binomial models when used at different spatial scales is important for not only future Lyme disease studies and Lyme disease risk assessment/management but any study that requires use of this model type in a spatial context. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Parameter estimation of the zero inflated negative binomial beta exponential distribution

    Science.gov (United States)

    Sirichantra, Chutima; Bodhisuwan, Winai

    2017-11-01

    The zero inflated negative binomial-beta exponential (ZINB-BE) distribution is developed, it is an alternative distribution for the excessive zero counts with overdispersion. The ZINB-BE distribution is a mixture of two distributions which are Bernoulli and negative binomial-beta exponential distributions. In this work, some characteristics of the proposed distribution are presented, such as, mean and variance. The maximum likelihood estimation is applied to parameter estimation of the proposed distribution. Finally some results of Monte Carlo simulation study, it seems to have high-efficiency when the sample size is large.

  18. A Mixed-Effects Heterogeneous Negative Binomial Model for Postfire Conifer Regeneration in Northeastern California, USA

    Science.gov (United States)

    Justin S. Crotteau; Martin W. Ritchie; J. Morgan. Varner

    2014-01-01

    Many western USA fire regimes are typified by mixed-severity fire, which compounds the variability inherent to natural regeneration densities in associated forests. Tree regeneration data are often discrete and nonnegative; accordingly, we fit a series of Poisson and negative binomial variation models to conifer seedling counts across four distinct burn severities and...

  19. Marginalized zero-inflated negative binomial regression with application to dental caries.

    Science.gov (United States)

    Preisser, John S; Das, Kalyan; Long, D Leann; Divaris, Kimon

    2016-05-10

    The zero-inflated negative binomial regression model (ZINB) is often employed in diverse fields such as dentistry, health care utilization, highway safety, and medicine to examine relationships between exposures of interest and overdispersed count outcomes exhibiting many zeros. The regression coefficients of ZINB have latent class interpretations for a susceptible subpopulation at risk for the disease/condition under study with counts generated from a negative binomial distribution and for a non-susceptible subpopulation that provides only zero counts. The ZINB parameters, however, are not well-suited for estimating overall exposure effects, specifically, in quantifying the effect of an explanatory variable in the overall mixture population. In this paper, a marginalized zero-inflated negative binomial regression (MZINB) model for independent responses is proposed to model the population marginal mean count directly, providing straightforward inference for overall exposure effects based on maximum likelihood estimation. Through simulation studies, the finite sample performance of MZINB is compared with marginalized zero-inflated Poisson, Poisson, and negative binomial regression. The MZINB model is applied in the evaluation of a school-based fluoride mouthrinse program on dental caries in 677 children. Copyright © 2015 John Wiley & Sons, Ltd.

  20. Estimating cavity tree and snag abundance using negative binomial regression models and nearest neighbor imputation methods

    Science.gov (United States)

    Bianca N.I. Eskelson; Hailemariam Temesgen; Tara M. Barrett

    2009-01-01

    Cavity tree and snag abundance data are highly variable and contain many zero observations. We predict cavity tree and snag abundance from variables that are readily available from forest cover maps or remotely sensed data using negative binomial (NB), zero-inflated NB, and zero-altered NB (ZANB) regression models as well as nearest neighbor (NN) imputation methods....

  1. The negative binomial distribution as a model for external corrosion defect counts in buried pipelines

    International Nuclear Information System (INIS)

    Valor, Alma; Alfonso, Lester; Caleyo, Francisco; Vidal, Julio; Perez-Baruch, Eloy; Hallen, José M.

    2015-01-01

    Highlights: • Observed external-corrosion defects in underground pipelines revealed a tendency to cluster. • The Poisson distribution is unable to fit extensive count data for these type of defects. • In contrast, the negative binomial distribution provides a suitable count model for them. • Two spatial stochastic processes lead to the negative binomial distribution for defect counts. • They are the Gamma-Poisson mixed process and the compound Poisson process. • A Rogeŕs process also arises as a plausible temporal stochastic process leading to corrosion defect clustering and to negative binomially distributed defect counts. - Abstract: The spatial distribution of external corrosion defects in buried pipelines is usually described as a Poisson process, which leads to corrosion defects being randomly distributed along the pipeline. However, in real operating conditions, the spatial distribution of defects considerably departs from Poisson statistics due to the aggregation of defects in groups or clusters. In this work, the statistical analysis of real corrosion data from underground pipelines operating in southern Mexico leads to conclude that the negative binomial distribution provides a better description for defect counts. The origin of this distribution from several processes is discussed. The analysed processes are: mixed Gamma-Poisson, compound Poisson and Roger’s processes. The physical reasons behind them are discussed for the specific case of soil corrosion.

  2. Use of the negative binomial-truncated Poisson distribution in thunderstorm prediction

    Science.gov (United States)

    Cohen, A. C.

    1971-01-01

    A probability model is presented for the distribution of thunderstorms over a small area given that thunderstorm events (1 or more thunderstorms) are occurring over a larger area. The model incorporates the negative binomial and truncated Poisson distributions. Probability tables for Cape Kennedy for spring, summer, and fall months and seasons are presented. The computer program used to compute these probabilities is appended.

  3. Negative binomial distribution for multiplicity distributions in e/sup +/e/sup -/ annihilation

    International Nuclear Information System (INIS)

    Chew, C.K.; Lim, Y.K.

    1986-01-01

    The authors show that the negative binomial distribution fits excellently the available charged-particle multiplicity distributions of e/sup +/e/sup -/ annihilation into hadrons at three different energies √s = 14, 22 and 34 GeV

  4. Time evolution of negative binomial optical field in a diffusion channel

    International Nuclear Information System (INIS)

    Liu Tang-Kun; Wu Pan-Pan; Shan Chuan-Jia; Liu Ji-Bing; Fan Hong-Yi

    2015-01-01

    We find the time evolution law of a negative binomial optical field in a diffusion channel. We reveal that by adjusting the diffusion parameter, the photon number can be controlled. Therefore, the diffusion process can be considered a quantum controlling scheme through photon addition. (paper)

  5. NBLDA: negative binomial linear discriminant analysis for RNA-Seq data.

    Science.gov (United States)

    Dong, Kai; Zhao, Hongyu; Tong, Tiejun; Wan, Xiang

    2016-09-13

    RNA-sequencing (RNA-Seq) has become a powerful technology to characterize gene expression profiles because it is more accurate and comprehensive than microarrays. Although statistical methods that have been developed for microarray data can be applied to RNA-Seq data, they are not ideal due to the discrete nature of RNA-Seq data. The Poisson distribution and negative binomial distribution are commonly used to model count data. Recently, Witten (Annals Appl Stat 5:2493-2518, 2011) proposed a Poisson linear discriminant analysis for RNA-Seq data. The Poisson assumption may not be as appropriate as the negative binomial distribution when biological replicates are available and in the presence of overdispersion (i.e., when the variance is larger than or equal to the mean). However, it is more complicated to model negative binomial variables because they involve a dispersion parameter that needs to be estimated. In this paper, we propose a negative binomial linear discriminant analysis for RNA-Seq data. By Bayes' rule, we construct the classifier by fitting a negative binomial model, and propose some plug-in rules to estimate the unknown parameters in the classifier. The relationship between the negative binomial classifier and the Poisson classifier is explored, with a numerical investigation of the impact of dispersion on the discriminant score. Simulation results show the superiority of our proposed method. We also analyze two real RNA-Seq data sets to demonstrate the advantages of our method in real-world applications. We have developed a new classifier using the negative binomial model for RNA-seq data classification. Our simulation results show that our proposed classifier has a better performance than existing works. The proposed classifier can serve as an effective tool for classifying RNA-seq data. Based on the comparison results, we have provided some guidelines for scientists to decide which method should be used in the discriminant analysis of RNA-Seq data

  6. Poisson and negative binomial item count techniques for surveys with sensitive question.

    Science.gov (United States)

    Tian, Guo-Liang; Tang, Man-Lai; Wu, Qin; Liu, Yin

    2017-04-01

    Although the item count technique is useful in surveys with sensitive questions, privacy of those respondents who possess the sensitive characteristic of interest may not be well protected due to a defect in its original design. In this article, we propose two new survey designs (namely the Poisson item count technique and negative binomial item count technique) which replace several independent Bernoulli random variables required by the original item count technique with a single Poisson or negative binomial random variable, respectively. The proposed models not only provide closed form variance estimate and confidence interval within [0, 1] for the sensitive proportion, but also simplify the survey design of the original item count technique. Most importantly, the new designs do not leak respondents' privacy. Empirical results show that the proposed techniques perform satisfactorily in the sense that it yields accurate parameter estimate and confidence interval.

  7. Use of a negative binomial distribution to describe the presence of Sphyrion laevigatum in Genypterus blacodes

    Directory of Open Access Journals (Sweden)

    Patricio Peña-Rehbein

    Full Text Available This paper describes the frequency and number of Sphyrion laevigatum in the skin of Genypterus blacodes, an important economic resource in Chile. The analysis of a spatial distribution model indicated that the parasites tended to cluster. Variations in the number of parasites per host could be described by a negative binomial distribution. The maximum number of parasites observed per host was two.

  8. Negative binomial multiplicity distributions, a new empirical law for high energy collisions

    International Nuclear Information System (INIS)

    Van Hove, L.; Giovannini, A.

    1987-01-01

    For a variety of high energy hadron production reactions, recent experiments have confirmed the findings of the UA5 Collaboration that charged particle multiplicities in central (pseudo) rapidity intervals and in full phase space obey negative binomial (NB) distributions. The authors discuss the meaning of this new empirical law on the basis of new data and they show that they support the interpretation of the NB distributions in terms of a cascading mechanism of hardron production

  9. Zero inflated Poisson and negative binomial regression models: application in education.

    Science.gov (United States)

    Salehi, Masoud; Roudbari, Masoud

    2015-01-01

    The number of failed courses and semesters in students are indicators of their performance. These amounts have zero inflated (ZI) distributions. Using ZI Poisson and negative binomial distributions we can model these count data to find the associated factors and estimate the parameters. This study aims at to investigate the important factors related to the educational performance of students. This cross-sectional study performed in 2008-2009 at Iran University of Medical Sciences (IUMS) with a population of almost 6000 students, 670 students selected using stratified random sampling. The educational and demographical data were collected using the University records. The study design was approved at IUMS and the students' data kept confidential. The descriptive statistics and ZI Poisson and negative binomial regressions were used to analyze the data. The data were analyzed using STATA. In the number of failed semesters, Poisson and negative binomial distributions with ZI, students' total average and quota system had the most roles. For the number of failed courses, total average, and being in undergraduate or master levels had the most effect in both models. In all models the total average have the most effect on the number of failed courses or semesters. The next important factor is quota system in failed semester and undergraduate and master levels in failed courses. Therefore, average has an important inverse effect on the numbers of failed courses and semester.

  10. Marginal likelihood estimation of negative binomial parameters with applications to RNA-seq data.

    Science.gov (United States)

    León-Novelo, Luis; Fuentes, Claudio; Emerson, Sarah

    2017-10-01

    RNA-Seq data characteristically exhibits large variances, which need to be appropriately accounted for in any proposed model. We first explore the effects of this variability on the maximum likelihood estimator (MLE) of the dispersion parameter of the negative binomial distribution, and propose instead to use an estimator obtained via maximization of the marginal likelihood in a conjugate Bayesian framework. We show, via simulation studies, that the marginal MLE can better control this variation and produce a more stable and reliable estimator. We then formulate a conjugate Bayesian hierarchical model, and use this new estimator to propose a Bayesian hypothesis test to detect differentially expressed genes in RNA-Seq data. We use numerical studies to show that our much simpler approach is competitive with other negative binomial based procedures, and we use a real data set to illustrate the implementation and flexibility of the procedure. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Bayesian analysis of overdispersed chromosome aberration data with the negative binomial model

    International Nuclear Information System (INIS)

    Brame, R.S.; Groer, P.G.

    2002-01-01

    The usual assumption of a Poisson model for the number of chromosome aberrations in controlled calibration experiments implies variance equal to the mean. However, it is known that chromosome aberration data from experiments involving high linear energy transfer radiations can be overdispersed, i.e. the variance is greater than the mean. Present methods for dealing with overdispersed chromosome data rely on frequentist statistical techniques. In this paper, the problem of overdispersion is considered from a Bayesian standpoint. The Bayes Factor is used to compare Poisson and negative binomial models for two previously published calibration data sets describing the induction of dicentric chromosome aberrations by high doses of neutrons. Posterior densities for the model parameters, which characterise dose response and overdispersion are calculated and graphed. Calibrative densities are derived for unknown neutron doses from hypothetical radiation accident data to determine the impact of different model assumptions on dose estimates. The main conclusion is that an initial assumption of a negative binomial model is the conservative approach to chromosome dosimetry for high LET radiations. (author)

  12. Sample size determination for a three-arm equivalence trial of Poisson and negative binomial responses.

    Science.gov (United States)

    Chang, Yu-Wei; Tsong, Yi; Zhao, Zhigen

    2017-01-01

    Assessing equivalence or similarity has drawn much attention recently as many drug products have lost or will lose their patents in the next few years, especially certain best-selling biologics. To claim equivalence between the test treatment and the reference treatment when assay sensitivity is well established from historical data, one has to demonstrate both superiority of the test treatment over placebo and equivalence between the test treatment and the reference treatment. Thus, there is urgency for practitioners to derive a practical way to calculate sample size for a three-arm equivalence trial. The primary endpoints of a clinical trial may not always be continuous, but may be discrete. In this paper, the authors derive power function and discuss sample size requirement for a three-arm equivalence trial with Poisson and negative binomial clinical endpoints. In addition, the authors examine the effect of the dispersion parameter on the power and the sample size by varying its coefficient from small to large. In extensive numerical studies, the authors demonstrate that required sample size heavily depends on the dispersion parameter. Therefore, misusing a Poisson model for negative binomial data may easily lose power up to 20%, depending on the value of the dispersion parameter.

  13. Predicting expressway crash frequency using a random effect negative binomial model: A case study in China.

    Science.gov (United States)

    Ma, Zhuanglin; Zhang, Honglu; Chien, Steven I-Jy; Wang, Jin; Dong, Chunjiao

    2017-01-01

    To investigate the relationship between crash frequency and potential influence factors, the accident data for events occurring on a 50km long expressway in China, including 567 crash records (2006-2008), were collected and analyzed. Both the fixed-length and the homogeneous longitudinal grade methods were applied to divide the study expressway section into segments. A negative binomial (NB) model and a random effect negative binomial (RENB) model were developed to predict crash frequency. The parameters of both models were determined using the maximum likelihood (ML) method, and the mixed stepwise procedure was applied to examine the significance of explanatory variables. Three explanatory variables, including longitudinal grade, road width, and ratio of longitudinal grade and curve radius (RGR), were found as significantly affecting crash frequency. The marginal effects of significant explanatory variables to the crash frequency were analyzed. The model performance was determined by the relative prediction error and the cumulative standardized residual. The results show that the RENB model outperforms the NB model. It was also found that the model performance with the fixed-length segment method is superior to that with the homogeneous longitudinal grade segment method. Copyright © 2016. Published by Elsevier Ltd.

  14. Growth Estimators and Confidence Intervals for the Mean of Negative Binomial Random Variables with Unknown Dispersion

    Directory of Open Access Journals (Sweden)

    David Shilane

    2013-01-01

    Full Text Available The negative binomial distribution becomes highly skewed under extreme dispersion. Even at moderately large sample sizes, the sample mean exhibits a heavy right tail. The standard normal approximation often does not provide adequate inferences about the data's expected value in this setting. In previous work, we have examined alternative methods of generating confidence intervals for the expected value. These methods were based upon Gamma and Chi Square approximations or tail probability bounds such as Bernstein's inequality. We now propose growth estimators of the negative binomial mean. Under high dispersion, zero values are likely to be overrepresented in the data. A growth estimator constructs a normal-style confidence interval by effectively removing a small, predetermined number of zeros from the data. We propose growth estimators based upon multiplicative adjustments of the sample mean and direct removal of zeros from the sample. These methods do not require estimating the nuisance dispersion parameter. We will demonstrate that the growth estimators' confidence intervals provide improved coverage over a wide range of parameter values and asymptotically converge to the sample mean. Interestingly, the proposed methods succeed despite adding both bias and variance to the normal approximation.

  15. Squeezing and other non-classical features in k-photon anharmonic oscillator in binomial and negative binomial states of the field

    International Nuclear Information System (INIS)

    Joshi, A.; Lawande, S.V.

    1990-01-01

    A systematic study of squeezing obtained from k-photon anharmonic oscillator (with interaction hamiltonian of the form (a † ) k , k ≥ 2) interacting with light whose statistics can be varied from sub-Poissonian to poissonian via binomial state of field and super-Poissonian to poissonian via negative binomial state of field is presented. The authors predict that for all values of k there is a tendency increase in squeezing with increased sub-Poissonian character of the field while the reverse is true with super-Poissonian field. They also present non-classical behavior of the first order coherence function explicitly for k = 2 case (i.e., for two-photon anharmonic oscillator model used for a Kerr-like medium) with variation in the statistics of the input light

  16. Estimating spatial and temporal components of variation in count data using negative binomial mixed models

    Science.gov (United States)

    Irwin, Brian J.; Wagner, Tyler; Bence, James R.; Kepler, Megan V.; Liu, Weihai; Hayes, Daniel B.

    2013-01-01

    Partitioning total variability into its component temporal and spatial sources is a powerful way to better understand time series and elucidate trends. The data available for such analyses of fish and other populations are usually nonnegative integer counts of the number of organisms, often dominated by many low values with few observations of relatively high abundance. These characteristics are not well approximated by the Gaussian distribution. We present a detailed description of a negative binomial mixed-model framework that can be used to model count data and quantify temporal and spatial variability. We applied these models to data from four fishery-independent surveys of Walleyes Sander vitreus across the Great Lakes basin. Specifically, we fitted models to gill-net catches from Wisconsin waters of Lake Superior; Oneida Lake, New York; Saginaw Bay in Lake Huron, Michigan; and Ohio waters of Lake Erie. These long-term monitoring surveys varied in overall sampling intensity, the total catch of Walleyes, and the proportion of zero catches. Parameter estimation included the negative binomial scaling parameter, and we quantified the random effects as the variations among gill-net sampling sites, the variations among sampled years, and site × year interactions. This framework (i.e., the application of a mixed model appropriate for count data in a variance-partitioning context) represents a flexible approach that has implications for monitoring programs (e.g., trend detection) and for examining the potential of individual variance components to serve as response metrics to large-scale anthropogenic perturbations or ecological changes.

  17. Geographically weighted negative binomial regression applied to zonal level safety performance models.

    Science.gov (United States)

    Gomes, Marcos José Timbó Lima; Cunto, Flávio; da Silva, Alan Ricardo

    2017-09-01

    Generalized Linear Models (GLM) with negative binomial distribution for errors, have been widely used to estimate safety at the level of transportation planning. The limited ability of this technique to take spatial effects into account can be overcome through the use of local models from spatial regression techniques, such as Geographically Weighted Poisson Regression (GWPR). Although GWPR is a system that deals with spatial dependency and heterogeneity and has already been used in some road safety studies at the planning level, it fails to account for the possible overdispersion that can be found in the observations on road-traffic crashes. Two approaches were adopted for the Geographically Weighted Negative Binomial Regression (GWNBR) model to allow discrete data to be modeled in a non-stationary form and to take note of the overdispersion of the data: the first examines the constant overdispersion for all the traffic zones and the second includes the variable for each spatial unit. This research conducts a comparative analysis between non-spatial global crash prediction models and spatial local GWPR and GWNBR at the level of traffic zones in Fortaleza/Brazil. A geographic database of 126 traffic zones was compiled from the available data on exposure, network characteristics, socioeconomic factors and land use. The models were calibrated by using the frequency of injury crashes as a dependent variable and the results showed that GWPR and GWNBR achieved a better performance than GLM for the average residuals and likelihood as well as reducing the spatial autocorrelation of the residuals, and the GWNBR model was more able to capture the spatial heterogeneity of the crash frequency. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The effect of the negative binomial distribution on the line-width of the micromaser cavity field

    International Nuclear Information System (INIS)

    Kremid, A. M.

    2009-01-01

    The influence of negative binomial distribution (NBD) on the line-width of the negative binomial distribution (NBD) on the line-width of the micromaser is considered. The threshold of the micromaser is shifted towards higher values of the pumping parameter q. Moreover the line-width exhibits sharp dips 'resonances' when the cavity temperature reduces to a very low value. These dips are very clear evidence for the occurrence of the so-called trapping states regime in the micromaser. This statistics prevents the appearance of these trapping states, namely by increasing the negative binomial parameter q these dips wash out and the line-width becomes more broadening. For small values of the parameter q the line-width at large values of q randomly oscillates around its transition line. As q becomes large this oscillatory behavior occurs at rarely values of q. (author)

  19. The importance of distribution-choice in modeling substance use data: a comparison of negative binomial, beta binomial, and zero-inflated distributions.

    Science.gov (United States)

    Wagner, Brandie; Riggs, Paula; Mikulich-Gilbertson, Susan

    2015-01-01

    It is important to correctly understand the associations among addiction to multiple drugs and between co-occurring substance use and psychiatric disorders. Substance-specific outcomes (e.g. number of days used cannabis) have distributional characteristics which range widely depending on the substance and the sample being evaluated. We recommend a four-part strategy for determining the appropriate distribution for modeling substance use data. We demonstrate this strategy by comparing the model fit and resulting inferences from applying four different distributions to model use of substances that range greatly in the prevalence and frequency of their use. Using Timeline Followback (TLFB) data from a previously-published study, we used negative binomial, beta-binomial and their zero-inflated counterparts to model proportion of days during treatment of cannabis, cigarettes, alcohol, and opioid use. The fit for each distribution was evaluated with statistical model selection criteria, visual plots and a comparison of the resulting inferences. We demonstrate the feasibility and utility of modeling each substance individually and show that no single distribution provides the best fit for all substances. Inferences regarding use of each substance and associations with important clinical variables were not consistent across models and differed by substance. Thus, the distribution chosen for modeling substance use must be carefully selected and evaluated because it may impact the resulting conclusions. Furthermore, the common procedure of aggregating use across different substances may not be ideal.

  20. Comparison of multiplicity distributions to the negative binomial distribution in muon-proton scattering

    International Nuclear Information System (INIS)

    Arneodo, M.; Ferrero, M.I.; Peroni, C.; Bee, C.P.; Bird, I.; Coughlan, J.; Sloan, T.; Braun, H.; Brueck, H.; Drees, J.; Edwards, A.; Krueger, J.; Montgomery, H.E.; Peschel, H.; Pietrzyk, U.; Poetsch, M.; Schneider, A.; Dreyer, T.; Ernst, T.; Haas, J.; Kabuss, E.M.; Landgraf, U.; Mohr, W.; Rith, K.; Schlagboehmer, A.; Schroeder, T.; Stier, H.E.; Wallucks, W.

    1987-01-01

    The multiplicity distributions of charged hadrons produced in the deep inelastic muon-proton scattering at 280 GeV are analysed in various rapidity intervals, as a function of the total hadronic centre of mass energy W ranging from 4-20 GeV. Multiplicity distributions for the backward and forward hemispheres are also analysed separately. The data can be well parameterized by binomial distributions, extending their range of applicability to the case of lepton-proton scattering. The energy and the rapidity dependence of the parameters is presented and a smooth transition from the binomial distribution via Poissonian to the ordinary binomial is observed. (orig.)

  1. [Application of negative binomial regression and modified Poisson regression in the research of risk factors for injury frequency].

    Science.gov (United States)

    Cao, Qingqing; Wu, Zhenqiang; Sun, Ying; Wang, Tiezhu; Han, Tengwei; Gu, Chaomei; Sun, Yehuan

    2011-11-01

    To Eexplore the application of negative binomial regression and modified Poisson regression analysis in analyzing the influential factors for injury frequency and the risk factors leading to the increase of injury frequency. 2917 primary and secondary school students were selected from Hefei by cluster random sampling method and surveyed by questionnaire. The data on the count event-based injuries used to fitted modified Poisson regression and negative binomial regression model. The risk factors incurring the increase of unintentional injury frequency for juvenile students was explored, so as to probe the efficiency of these two models in studying the influential factors for injury frequency. The Poisson model existed over-dispersion (P binomial regression model, was fitted better. respectively. Both showed that male gender, younger age, father working outside of the hometown, the level of the guardian being above junior high school and smoking might be the results of higher injury frequencies. On a tendency of clustered frequency data on injury event, both the modified Poisson regression analysis and negative binomial regression analysis can be used. However, based on our data, the modified Poisson regression fitted better and this model could give a more accurate interpretation of relevant factors affecting the frequency of injury.

  2. Robust inference in the negative binomial regression model with an application to falls data.

    Science.gov (United States)

    Aeberhard, William H; Cantoni, Eva; Heritier, Stephane

    2014-12-01

    A popular way to model overdispersed count data, such as the number of falls reported during intervention studies, is by means of the negative binomial (NB) distribution. Classical estimating methods are well-known to be sensitive to model misspecifications, taking the form of patients falling much more than expected in such intervention studies where the NB regression model is used. We extend in this article two approaches for building robust M-estimators of the regression parameters in the class of generalized linear models to the NB distribution. The first approach achieves robustness in the response by applying a bounded function on the Pearson residuals arising in the maximum likelihood estimating equations, while the second approach achieves robustness by bounding the unscaled deviance components. For both approaches, we explore different choices for the bounding functions. Through a unified notation, we show how close these approaches may actually be as long as the bounding functions are chosen and tuned appropriately, and provide the asymptotic distributions of the resulting estimators. Moreover, we introduce a robust weighted maximum likelihood estimator for the overdispersion parameter, specific to the NB distribution. Simulations under various settings show that redescending bounding functions yield estimates with smaller biases under contamination while keeping high efficiency at the assumed model, and this for both approaches. We present an application to a recent randomized controlled trial measuring the effectiveness of an exercise program at reducing the number of falls among people suffering from Parkinsons disease to illustrate the diagnostic use of such robust procedures and their need for reliable inference. © 2014, The International Biometric Society.

  3. The negative binomial-Lindley generalized linear model: characteristics and application using crash data.

    Science.gov (United States)

    Geedipally, Srinivas Reddy; Lord, Dominique; Dhavala, Soma Sekhar

    2012-03-01

    There has been a considerable amount of work devoted by transportation safety analysts to the development and application of new and innovative models for analyzing crash data. One important characteristic about crash data that has been documented in the literature is related to datasets that contained a large amount of zeros and a long or heavy tail (which creates highly dispersed data). For such datasets, the number of sites where no crash is observed is so large that traditional distributions and regression models, such as the Poisson and Poisson-gamma or negative binomial (NB) models cannot be used efficiently. To overcome this problem, the NB-Lindley (NB-L) distribution has recently been introduced for analyzing count data that are characterized by excess zeros. The objective of this paper is to document the application of a NB generalized linear model with Lindley mixed effects (NB-L GLM) for analyzing traffic crash data. The study objective was accomplished using simulated and observed datasets. The simulated dataset was used to show the general performance of the model. The model was then applied to two datasets based on observed data. One of the dataset was characterized by a large amount of zeros. The NB-L GLM was compared with the NB and zero-inflated models. Overall, the research study shows that the NB-L GLM not only offers superior performance over the NB and zero-inflated models when datasets are characterized by a large number of zeros and a long tail, but also when the crash dataset is highly dispersed. Published by Elsevier Ltd.

  4. Two-part zero-inflated negative binomial regression model for quantitative trait loci mapping with count trait.

    Science.gov (United States)

    Moghimbeigi, Abbas

    2015-05-07

    Poisson regression models provide a standard framework for quantitative trait locus (QTL) mapping of count traits. In practice, however, count traits are often over-dispersed relative to the Poisson distribution. In these situations, the zero-inflated Poisson (ZIP), zero-inflated generalized Poisson (ZIGP) and zero-inflated negative binomial (ZINB) regression may be useful for QTL mapping of count traits. Added genetic variables to the negative binomial part equation, may also affect extra zero data. In this study, to overcome these challenges, I apply two-part ZINB model. The EM algorithm with Newton-Raphson method in the M-step uses for estimating parameters. An application of the two-part ZINB model for QTL mapping is considered to detect associations between the formation of gallstone and the genotype of markers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Negative binomial distribution to describe the presence of Trifur tortuosus (Crustacea: Copepoda in Merluccius gayi (Osteichthyes: Gadiformes

    Directory of Open Access Journals (Sweden)

    Giselle Garcia-Sepulveda

    2017-06-01

    Full Text Available This paper describes the frequency and number of Trifur tortuosus in the skin of Merluccius gayi, an important economic resource in Chile. Analysis of a spatial distribution model indicated that the parasites tended to cluster. Variations in the number of parasites per host can be described by a negative binomial distribution. The maximum number of parasites observed per host was one, similar patterns was described for other parasites in Chilean marine fishes.

  6. Negative-binomial multiplicity distributions in the interaction of light ions with 12C at 4.2 GeV/c

    International Nuclear Information System (INIS)

    Tucholski, A.; Bogdanowicz, J.; Moroz, Z.; Wojtkowska, J.

    1989-01-01

    Multiplicity distribution of single-charged particles in the interaction of p, d, α and 12 C projectiles with C target nuclei at 4.2 GeV/c were analysed in terms of the negative binomial distribution. The experimental data obtained by the Dubna Propane Bubble Chamber Group were used. It is shown that the experimental distributions are satisfactorily described by the negative-binomial distribution. Values of the parameters of these distributions are discussed. (orig.)

  7. Validity of the negative binomial multiplicity distribution in case of ultra-relativistic nucleus-nucleus interaction in different azimuthal bins

    International Nuclear Information System (INIS)

    Ghosh, D.; Deb, A.; Haldar, P.K.; Sahoo, S.R.; Maity, D.

    2004-01-01

    This work studies the validity of the negative binomial distribution in the multiplicity distribution of charged secondaries in 16 O and 32 S interactions with AgBr at 60 GeV/c per nucleon and 200 GeV/c per nucleon, respectively. The validity of negative binomial distribution (NBD) is studied in different azimuthal phase spaces. It is observed that the data can be well parameterized in terms of the NBD law for different azimuthal phase spaces. (authors)

  8. Risk indicators of oral health status among young adults aged 18 years analyzed by negative binomial regression.

    Science.gov (United States)

    Lu, Hai-Xia; Wong, May Chun Mei; Lo, Edward Chin Man; McGrath, Colman

    2013-08-19

    Limited information on oral health status for young adults aged 18 year-olds is known, and no available data exists in Hong Kong. The aims of this study were to investigate the oral health status and its risk indicators among young adults in Hong Kong using negative binomial regression. A survey was conducted in a representative sample of Hong Kong young adults aged 18 years. Clinical examinations were taken to assess oral health status using DMFT index and Community Periodontal Index (CPI) according to WHO criteria. Negative binomial regressions for DMFT score and the number of sextants with healthy gums were performed to identify the risk indicators of oral health status. A total of 324 young adults were examined. Prevalence of dental caries experience among the subjects was 59% and the overall mean DMFT score was 1.4. Most subjects (95%) had a score of 2 as their highest CPI score. Negative binomial regression analyses revealed that subjects who had a dental visit within 3 years had significantly higher DMFT scores (IRR = 1.68, p < 0.001). Subjects who brushed their teeth more frequently (IRR = 1.93, p < 0.001) and those with better dental knowledge (IRR = 1.09, p = 0.002) had significantly more sextants with healthy gums. Dental caries experience of the young adults aged 18 years in Hong Kong was not high but their periodontal condition was unsatisfactory. Their oral health status was related to their dental visit behavior, oral hygiene habit, and oral health knowledge.

  9. The validity of the negative binomial multiplicity distribution in the case of the relativistic nucleus-nucleus interaction

    International Nuclear Information System (INIS)

    Ghosh, D.; Mukhopadhyay, A.; Ghosh, A.; Roy, J.

    1989-01-01

    This letter presents new data on the multiplicity distribution of charged secondaries in 24 Mg interactions with AgBr at 4.5 GeV/c per nucleon. The validity of the negative binomial distribution (NBD) is studied. It is observed that the data can be well parametrized in terms of the NBD law for the whole phase space and also for different pseudo-rapidity bins. A comparison of different parameters with those in the case of h-h interactions reveals some interesting results, the implications of which are discussed. (orig.)

  10. Deteksi Dini Kasus Demam Berdarah Dengue Berdasarkan Faktor Cuaca di DKI Jakarta Menggunakan Metode Zero Truncated Negative Binomial

    Directory of Open Access Journals (Sweden)

    Robert Kurniawan

    2017-11-01

    Full Text Available AbstractThe incidence rates of DHF in Jakarta in 2010 to 2014 are always higher than that of the national rates. Therefore, this study aims to find the effect of weather parameter on DHF cases. Weather is chosen because it can be observed daily and can be predicted so that it can be used as earlydetection in estimating the number of DHF cases. Data use includes DHF cases which is collected daily and weather data including lowest and highest temperatures and rainfall. Data analysis used is zero-truncated negative binomial analysis at 10% significance level. Based on the periodic dataof selected variables from January 1st 2015 until May 31st 2015, the study revealed that weather factors consisting of highest temperature, lowest temperature, and rainfall rate were significant enough to predict the number of DHF patients in DKI Jakarta. The three variables had positiveeffects in influencing the number of DHF patients in the same period. However, the weather factors cannot be controlled by humans, so that appropriate preventions are required whenever weather’s predictions indicate the increasing number of DHF cases in DKI Jakarta.Keywords: Dengue Hemorrhagic Fever, zero truncated negative binomial, early warning.AbstrakAngka kesakitan DBD pada tahun 2010 hingga 2014 selalu lebih tinggi dibandingkan dengan angka kesakitan DBD nasional. Oleh karena itu, penelitian ini bertujuan untuk mencari pengaruh faktor cuaca terhadap kasus DBD. Faktor cuaca dipilih karena dapat diamati setiap harinya dan dapat diprediksi sehingga dapat dijadikan deteksi dini dalam perkiraan jumlah penderita DBD. Data yang digunakan dalam penelitian ini adalah data jumlah penderita DBD di DKI Jakarta per hari dan data cuaca yang meliputi suhu terendah, suhu tertinggi dan curah hujan. Untuk mengetahui pengaruh faktor cuaca tersebut terhadap jumlah penderita DBD di DKI Jakarta digunakan metode analisis zero-truncated negative binomial. Berdasarkan data periode 1 Januari 2015 hingga

  11. The analysis of incontinence episodes and other count data in patients with overactive bladder by Poisson and negative binomial regression.

    Science.gov (United States)

    Martina, R; Kay, R; van Maanen, R; Ridder, A

    2015-01-01

    Clinical studies in overactive bladder have traditionally used analysis of covariance or nonparametric methods to analyse the number of incontinence episodes and other count data. It is known that if the underlying distributional assumptions of a particular parametric method do not hold, an alternative parametric method may be more efficient than a nonparametric one, which makes no assumptions regarding the underlying distribution of the data. Therefore, there are advantages in using methods based on the Poisson distribution or extensions of that method, which incorporate specific features that provide a modelling framework for count data. One challenge with count data is overdispersion, but methods are available that can account for this through the introduction of random effect terms in the modelling, and it is this modelling framework that leads to the negative binomial distribution. These models can also provide clinicians with a clearer and more appropriate interpretation of treatment effects in terms of rate ratios. In this paper, the previously used parametric and non-parametric approaches are contrasted with those based on Poisson regression and various extensions in trials evaluating solifenacin and mirabegron in patients with overactive bladder. In these applications, negative binomial models are seen to fit the data well. Copyright © 2014 John Wiley & Sons, Ltd.

  12. A comparison of different ways of including baseline counts in negative binomial models for data from falls prevention trials.

    Science.gov (United States)

    Zheng, Han; Kimber, Alan; Goodwin, Victoria A; Pickering, Ruth M

    2018-01-01

    A common design for a falls prevention trial is to assess falling at baseline, randomize participants into an intervention or control group, and ask them to record the number of falls they experience during a follow-up period of time. This paper addresses how best to include the baseline count in the analysis of the follow-up count of falls in negative binomial (NB) regression. We examine the performance of various approaches in simulated datasets where both counts are generated from a mixed Poisson distribution with shared random subject effect. Including the baseline count after log-transformation as a regressor in NB regression (NB-logged) or as an offset (NB-offset) resulted in greater power than including the untransformed baseline count (NB-unlogged). Cook and Wei's conditional negative binomial (CNB) model replicates the underlying process generating the data. In our motivating dataset, a statistically significant intervention effect resulted from the NB-logged, NB-offset, and CNB models, but not from NB-unlogged, and large, outlying baseline counts were overly influential in NB-unlogged but not in NB-logged. We conclude that there is little to lose by including the log-transformed baseline count in standard NB regression compared to CNB for moderate to larger sized datasets. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A methodology to design heuristics for model selection based on the characteristics of data: Application to investigate when the Negative Binomial Lindley (NB-L) is preferred over the Negative Binomial (NB).

    Science.gov (United States)

    Shirazi, Mohammadali; Dhavala, Soma Sekhar; Lord, Dominique; Geedipally, Srinivas Reddy

    2017-10-01

    Safety analysts usually use post-modeling methods, such as the Goodness-of-Fit statistics or the Likelihood Ratio Test, to decide between two or more competitive distributions or models. Such metrics require all competitive distributions to be fitted to the data before any comparisons can be accomplished. Given the continuous growth in introducing new statistical distributions, choosing the best one using such post-modeling methods is not a trivial task, in addition to all theoretical or numerical issues the analyst may face during the analysis. Furthermore, and most importantly, these measures or tests do not provide any intuitions into why a specific distribution (or model) is preferred over another (Goodness-of-Logic). This paper ponders into these issues by proposing a methodology to design heuristics for Model Selection based on the characteristics of data, in terms of descriptive summary statistics, before fitting the models. The proposed methodology employs two analytic tools: (1) Monte-Carlo Simulations and (2) Machine Learning Classifiers, to design easy heuristics to predict the label of the 'most-likely-true' distribution for analyzing data. The proposed methodology was applied to investigate when the recently introduced Negative Binomial Lindley (NB-L) distribution is preferred over the Negative Binomial (NB) distribution. Heuristics were designed to select the 'most-likely-true' distribution between these two distributions, given a set of prescribed summary statistics of data. The proposed heuristics were successfully compared against classical tests for several real or observed datasets. Not only they are easy to use and do not need any post-modeling inputs, but also, using these heuristics, the analyst can attain useful information about why the NB-L is preferred over the NB - or vice versa- when modeling data. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Sample Size Estimation for Negative Binomial Regression Comparing Rates of Recurrent Events with Unequal Follow-Up Time.

    Science.gov (United States)

    Tang, Yongqiang

    2015-01-01

    A sample size formula is derived for negative binomial regression for the analysis of recurrent events, in which subjects can have unequal follow-up time. We obtain sharp lower and upper bounds on the required size, which is easy to compute. The upper bound is generally only slightly larger than the required size, and hence can be used to approximate the sample size. The lower and upper size bounds can be decomposed into two terms. The first term relies on the mean number of events in each group, and the second term depends on two factors that measure, respectively, the extent of between-subject variability in event rates, and follow-up time. Simulation studies are conducted to assess the performance of the proposed method. An application of our formulae to a multiple sclerosis trial is provided.

  15. Sample size for comparing negative binomial rates in noninferiority and equivalence trials with unequal follow-up times.

    Science.gov (United States)

    Tang, Yongqiang

    2017-05-25

    We derive the sample size formulae for comparing two negative binomial rates based on both the relative and absolute rate difference metrics in noninferiority and equivalence trials with unequal follow-up times, and establish an approximate relationship between the sample sizes required for the treatment comparison based on the two treatment effect metrics. The proposed method allows the dispersion parameter to vary by treatment groups. The accuracy of these methods is assessed by simulations. It is demonstrated that ignoring the between-subject variation in the follow-up time by setting the follow-up time for all individuals to be the mean follow-up time may greatly underestimate the required size, resulting in underpowered studies. Methods are provided for back-calculating the dispersion parameter based on the published summary results.

  16. Comparison of linear and zero-inflated negative binomial regression models for appraisal of risk factors associated with dental caries

    Directory of Open Access Journals (Sweden)

    Manu Batra

    2016-01-01

    Full Text Available Context: Dental caries among children has been described as a pandemic disease with a multifactorial nature. Various sociodemographic factors and oral hygiene practices are commonly tested for their influence on dental caries. In recent years, a recent statistical model that allows for covariate adjustment has been developed and is commonly referred zero-inflated negative binomial (ZINB models. Aim: To compare the fit of the two models, the conventional linear regression (LR model and ZINB model to assess the risk factors associated with dental caries. Materials and Methods: A cross-sectional survey was conducted on 1138 12-year-old school children in Moradabad Town, Uttar Pradesh during months of February-August 2014. Selected participants were interviewed using a questionnaire. Dental caries was assessed by recording decayed, missing, or filled teeth (DMFT index. Statistical Analysis Used: To assess the risk factor associated with dental caries in children, two approaches have been applied - LR model and ZINB model. Results: The prevalence of caries-free subjects was 24.1%, and mean DMFT was 3.4 ± 1.8. In LR model, all the variables were statistically significant. Whereas in ZINB model, negative binomial part showed place of residence, father′s education level, tooth brushing frequency, and dental visit statistically significant implying that the degree of being caries-free (DMFT = 0 increases for group of children who are living in urban, whose father is university pass out, who brushes twice a day and if have ever visited a dentist. Conclusion: The current study report that the LR model is a poorly fitted model and may lead to spurious conclusions whereas ZINB model has shown better goodness of fit (Akaike information criterion values - LR: 3.94; ZINB: 2.39 and can be preferred if high variance and number of an excess of zeroes are present.

  17. Comparison of linear and zero-inflated negative binomial regression models for appraisal of risk factors associated with dental caries.

    Science.gov (United States)

    Batra, Manu; Shah, Aasim Farooq; Rajput, Prashant; Shah, Ishrat Aasim

    2016-01-01

    Dental caries among children has been described as a pandemic disease with a multifactorial nature. Various sociodemographic factors and oral hygiene practices are commonly tested for their influence on dental caries. In recent years, a recent statistical model that allows for covariate adjustment has been developed and is commonly referred zero-inflated negative binomial (ZINB) models. To compare the fit of the two models, the conventional linear regression (LR) model and ZINB model to assess the risk factors associated with dental caries. A cross-sectional survey was conducted on 1138 12-year-old school children in Moradabad Town, Uttar Pradesh during months of February-August 2014. Selected participants were interviewed using a questionnaire. Dental caries was assessed by recording decayed, missing, or filled teeth (DMFT) index. To assess the risk factor associated with dental caries in children, two approaches have been applied - LR model and ZINB model. The prevalence of caries-free subjects was 24.1%, and mean DMFT was 3.4 ± 1.8. In LR model, all the variables were statistically significant. Whereas in ZINB model, negative binomial part showed place of residence, father's education level, tooth brushing frequency, and dental visit statistically significant implying that the degree of being caries-free (DMFT = 0) increases for group of children who are living in urban, whose father is university pass out, who brushes twice a day and if have ever visited a dentist. The current study report that the LR model is a poorly fitted model and may lead to spurious conclusions whereas ZINB model has shown better goodness of fit (Akaike information criterion values - LR: 3.94; ZINB: 2.39) and can be preferred if high variance and number of an excess of zeroes are present.

  18. Single-vehicle crashes along rural mountainous highways in Malaysia: An application of random parameters negative binomial model.

    Science.gov (United States)

    Rusli, Rusdi; Haque, Md Mazharul; King, Mark; Voon, Wong Shaw

    2017-05-01

    Mountainous highways generally associate with complex driving environment because of constrained road geometries, limited cross-section elements, inappropriate roadside features, and adverse weather conditions. As a result, single-vehicle (SV) crashes are overrepresented along mountainous roads, particularly in developing countries, but little attention is known about the roadway geometric, traffic and weather factors contributing to these SV crashes. As such, the main objective of the present study is to investigate SV crashes using detailed data obtained from a rigorous site survey and existing databases. The final dataset included a total of 56 variables representing road geometries including horizontal and vertical alignment, traffic characteristics, real-time weather condition, cross-sectional elements, roadside features, and spatial characteristics. To account for structured heterogeneities resulting from multiple observations within a site and other unobserved heterogeneities, the study applied a random parameters negative binomial model. Results suggest that rainfall during the crash is positively associated with SV crashes, but real-time visibility is negatively associated. The presence of a road shoulder, particularly a bitumen shoulder or wider shoulders, along mountainous highways is associated with less SV crashes. While speeding along downgrade slopes increases the likelihood of SV crashes, proper delineation decreases the likelihood. Findings of this study have significant implications for designing safer highways in mountainous areas, particularly in the context of a developing country. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Distinguishing between Rural and Urban Road Segment Traffic Safety Based on Zero-Inflated Negative Binomial Regression Models

    Directory of Open Access Journals (Sweden)

    Xuedong Yan

    2012-01-01

    Full Text Available In this study, the traffic crash rate, total crash frequency, and injury and fatal crash frequency were taken into consideration for distinguishing between rural and urban road segment safety. The GIS-based crash data during four and half years in Pikes Peak Area, US were applied for the analyses. The comparative statistical results show that the crash rates in rural segments are consistently lower than urban segments. Further, the regression results based on Zero-Inflated Negative Binomial (ZINB regression models indicate that the urban areas have a higher crash risk in terms of both total crash frequency and injury and fatal crash frequency, compared to rural areas. Additionally, it is found that crash frequencies increase as traffic volume and segment length increase, though the higher traffic volume lower the likelihood of severe crash occurrence; compared to 2-lane roads, the 4-lane roads have lower crash frequencies but have a higher probability of severe crash occurrence; and better road facilities with higher free flow speed can benefit from high standard design feature thus resulting in a lower total crash frequency, but they cannot mitigate the severe crash risk.

  20. Factors related to the use of antenatal care services in Ethiopia: Application of the zero-inflated negative binomial model.

    Science.gov (United States)

    Assefa, Enyew; Tadesse, Mekonnen

    2017-08-01

    The major causes for poor health in developing countries are inadequate access and under-use of modern health care services. The objective of this study was to identify and examine factors related to the use of antenatal care services using the 2011 Ethiopia Demographic and Health Survey data. The number of antenatal care visits during the last pregnancy by mothers aged 15 to 49 years (n = 7,737) was analyzed. More than 55% of the mothers did not use antenatal care (ANC) services, while more than 22% of the women used antenatal care services less than four times. More than half of the women (52%) who had access to health services had at least four antenatal care visits. The zero-inflated negative binomial model was found to be more appropriate for analyzing the data. Place of residence, age of mothers, woman's educational level, employment status, mass media exposure, religion, and access to health services were significantly associated with the use of antenatal care services. Accordingly, there should be progress toward a health-education program that enables more women to utilize ANC services, with the program targeting women in rural areas, uneducated women, and mothers with higher birth orders through appropriate media.

  1. Analysis of U.S. freight-train derailment severity using zero-truncated negative binomial regression and quantile regression.

    Science.gov (United States)

    Liu, Xiang; Saat, M Rapik; Qin, Xiao; Barkan, Christopher P L

    2013-10-01

    Derailments are the most common type of freight-train accidents in the United States. Derailments cause damage to infrastructure and rolling stock, disrupt services, and may cause casualties and harm the environment. Accordingly, derailment analysis and prevention has long been a high priority in the rail industry and government. Despite the low probability of a train derailment, the potential for severe consequences justify the need to better understand the factors influencing train derailment severity. In this paper, a zero-truncated negative binomial (ZTNB) regression model is developed to estimate the conditional mean of train derailment severity. Recognizing that the mean is not the only statistic describing data distribution, a quantile regression (QR) model is also developed to estimate derailment severity at different quantiles. The two regression models together provide a better understanding of train derailment severity distribution. Results of this work can be used to estimate train derailment severity under various operational conditions and by different accident causes. This research is intended to provide insights regarding development of cost-efficient train safety policies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Linking parasite populations in hosts to parasite populations in space through Taylor's law and the negative binomial distribution.

    Science.gov (United States)

    Cohen, Joel E; Poulin, Robert; Lagrue, Clément

    2017-01-03

    The spatial distribution of individuals of any species is a basic concern of ecology. The spatial distribution of parasites matters to control and conservation of parasites that affect human and nonhuman populations. This paper develops a quantitative theory to predict the spatial distribution of parasites based on the distribution of parasites in hosts and the spatial distribution of hosts. Four models are tested against observations of metazoan hosts and their parasites in littoral zones of four lakes in Otago, New Zealand. These models differ in two dichotomous assumptions, constituting a 2 × 2 theoretical design. One assumption specifies whether the variance function of the number of parasites per host individual is described by Taylor's law (TL) or the negative binomial distribution (NBD). The other assumption specifies whether the numbers of parasite individuals within each host in a square meter of habitat are independent or perfectly correlated among host individuals. We find empirically that the variance-mean relationship of the numbers of parasites per square meter is very well described by TL but is not well described by NBD. Two models that posit perfect correlation of the parasite loads of hosts in a square meter of habitat approximate observations much better than two models that posit independence of parasite loads of hosts in a square meter, regardless of whether the variance-mean relationship of parasites per host individual obeys TL or NBD. We infer that high local interhost correlations in parasite load strongly influence the spatial distribution of parasites. Local hotspots could influence control and conservation of parasites.

  3. Use of negative binomial distribution to describe the presence of Anisakis in Thyrsites atun Uso de distribuição binomial negativa para descrever a presença de Anisakis em Thyrsites atun

    Directory of Open Access Journals (Sweden)

    Patricio Peña-Rehbein

    2012-03-01

    Full Text Available Nematodes of the genus Anisakis have marine fishes as intermediate hosts. One of these hosts is Thyrsites atun, an important fishery resource in Chile between 38 and 41° S. This paper describes the frequency and number of Anisakis nematodes in the internal organs of Thyrsites atun. An analysis based on spatial distribution models showed that the parasites tend to be clustered. The variation in the number of parasites per host could be described by the negative binomial distribution. The maximum observed number of parasites was nine parasites per host. The environmental and zoonotic aspects of the study are also discussed.Nematóides do gênero Anisakis têm nos peixes marinhos seus hospedeiros intermediários. Um desses hospedeiros é Thyrsites atun, um importante recurso pesqueiro no Chile entre 38 e 41° S. Este artigo descreve a freqüência e o número de nematóides Anisakis nos órgãos internos de Thyrsites atun. Uma análise baseada em modelos de distribuição espacial demonstrou que os parasitos tendem a ficar agrupados. A variação numérica de parasitas por hospedeiro pôde ser descrita por distribuição binomial negativa. O número máximo observado de parasitas por hospedeiro foi nove. Os aspectos ambientais e zoonóticos desse estudo também serão discutidos.

  4. Using a Negative Binomial Regression Model for Early Warning at the Start of a Hand Foot Mouth Disease Epidemic in Dalian, Liaoning Province, China.

    Science.gov (United States)

    An, Qingyu; Wu, Jun; Fan, Xuesong; Pan, Liyang; Sun, Wei

    2016-01-01

    The hand foot and mouth disease (HFMD) is a human syndrome caused by intestinal viruses like that coxsackie A virus 16, enterovirus 71 and easily developed into outbreak in kindergarten and school. Scientifically and accurately early detection of the start time of HFMD epidemic is a key principle in planning of control measures and minimizing the impact of HFMD. The objective of this study was to establish a reliable early detection model for start timing of hand foot mouth disease epidemic in Dalian and to evaluate the performance of model by analyzing the sensitivity in detectability. The negative binomial regression model was used to estimate the weekly baseline case number of HFMD and identified the optimal alerting threshold between tested difference threshold values during the epidemic and non-epidemic year. Circular distribution method was used to calculate the gold standard of start timing of HFMD epidemic. From 2009 to 2014, a total of 62022 HFMD cases were reported (36879 males and 25143 females) in Dalian, Liaoning Province, China, including 15 fatal cases. The median age of the patients was 3 years. The incidence rate of epidemic year ranged from 137.54 per 100,000 population to 231.44 per 100,000population, the incidence rate of non-epidemic year was lower than 112 per 100,000 population. The negative binomial regression model with AIC value 147.28 was finally selected to construct the baseline level. The threshold value was 100 for the epidemic year and 50 for the non- epidemic year had the highest sensitivity(100%) both in retrospective and prospective early warning and the detection time-consuming was 2 weeks before the actual starting of HFMD epidemic. The negative binomial regression model could early warning the start of a HFMD epidemic with good sensitivity and appropriate detection time in Dalian.

  5. Generalized negative binomial distribution: a promising statistical distribution for Oncomelania hupensis in the lake- and marsh-land regions of China.

    Science.gov (United States)

    Zhang, Z J; Ong, S H; Lynn, H S; Peng, W X; Zhou, Y B; Zhao, G M; Jiang, Q W

    2008-09-01

    A new generalization of the negative binomial distribution (GNBD) is introduced and fitted to counts of Oncomelania hupensis, the intermediate host of Schistosoma japonicum, made, in areas of Chinese lakeland and marshland, early in the winter of 2005 and late in the spring of 2006. The GNBD was found to fit the snail data better than the standard negative binomial distribution (NBD) that has previously been widely used to model the distribution of O. hupensis. With two more parameters than the NBD, the GNBD can integrate many discrete distributions and is more flexible than the NBD in modelling O. hupensis. It also provides a better theoretical distribution for the quantitative study of O. hupensis, especially in building an accurate prediction model of snail density. The justification for adopting the GNBD is discussed. The GNBD allows researchers to broaden the field in the quantitative study not only of O. hupensis and schistosomiasis japonica but also of other environment-related helminthiases and family-clustered diseases that have, traditionally, been modelled using the NBD.

  6. First study of the negative binomial distribution applied to higher moments of net-charge and net-proton multiplicity distributions

    International Nuclear Information System (INIS)

    Tarnowsky, Terence J.; Westfall, Gary D.

    2013-01-01

    A study of the first four moments (mean, variance, skewness, and kurtosis) and their products (κσ 2 and Sσ) of the net-charge and net-proton distributions in Au + Au collisions at √(s NN )=7.7–200 GeV from HIJING simulations has been carried out. The skewness and kurtosis and the collision volume independent products κσ 2 and Sσ have been proposed as sensitive probes for identifying the presence of a QCD critical point. A discrete probability distribution that effectively describes the separate positively and negatively charged particle (or proton and anti-proton) multiplicity distributions is the negative binomial (or binomial) distribution (NBD/BD). The NBD/BD has been used to characterize particle production in high-energy particle and nuclear physics. Their application to the higher moments of the net-charge and net-proton distributions is examined. Differences between κσ 2 and a statistical Poisson assumption of a factor of four (for net-charge) and 40% (for net-protons) can be accounted for by the NBD/BD. This is the first application of the properties of the NBD/BD to describe the behavior of the higher moments of net-charge and net-proton distributions in nucleus–nucleus collisions

  7. Hurdles run technique analysis in the 400m hurdles

    OpenAIRE

    Drtina, Martin

    2010-01-01

    Hurdles run technique analysis in the 400m hurdles Thesis objectives: The main objective is to compare the technique hurdles run in the race tempo on the track 400 m hurdles at the selected probands. Tasks are identified kinematic parameters separately for each proband and identify their weaknesses in technique. Method: Analysis techniques hurdles run was done by using 3D kinematic analysis. Observed space-time events were recorded on two digital cameras. Records was transferred to a suitable...

  8. Predictability and interpretability of hybrid link-level crash frequency models for urban arterials compared to cluster-based and general negative binomial regression models.

    Science.gov (United States)

    Najaf, Pooya; Duddu, Venkata R; Pulugurtha, Srinivas S

    2018-03-01

    Machine learning (ML) techniques have higher prediction accuracy compared to conventional statistical methods for crash frequency modelling. However, their black-box nature limits the interpretability. The objective of this research is to combine both ML and statistical methods to develop hybrid link-level crash frequency models with high predictability and interpretability. For this purpose, M5' model trees method (M5') is introduced and applied to classify the crash data and then calibrate a model for each homogenous class. The data for 1134 and 345 randomly selected links on urban arterials in the city of Charlotte, North Carolina was used to develop and validate models, respectively. The outputs from the hybrid approach are compared with the outputs from cluster-based negative binomial regression (NBR) and general NBR models. Findings indicate that M5' has high predictability and is very reliable to interpret the role of different attributes on crash frequency compared to other developed models.

  9. Regular exercise and related factors in patients with Parkinson's disease: Applying zero-inflated negative binomial modeling of exercise count data.

    Science.gov (United States)

    Lee, JuHee; Park, Chang Gi; Choi, Moonki

    2016-05-01

    This study was conducted to identify risk factors that influence regular exercise among patients with Parkinson's disease in Korea. Parkinson's disease is prevalent in the elderly, and may lead to a sedentary lifestyle. Exercise can enhance physical and psychological health. However, patients with Parkinson's disease are less likely to exercise than are other populations due to physical disability. A secondary data analysis and cross-sectional descriptive study were conducted. A convenience sample of 106 patients with Parkinson's disease was recruited at an outpatient neurology clinic of a tertiary hospital in Korea. Demographic characteristics, disease-related characteristics (including disease duration and motor symptoms), self-efficacy for exercise, balance, and exercise level were investigated. Negative binomial regression and zero-inflated negative binomial regression for exercise count data were utilized to determine factors involved in exercise. The mean age of participants was 65.85 ± 8.77 years, and the mean duration of Parkinson's disease was 7.23 ± 6.02 years. Most participants indicated that they engaged in regular exercise (80.19%). Approximately half of participants exercised at least 5 days per week for 30 min, as recommended (51.9%). Motor symptoms were a significant predictor of exercise in the count model, and self-efficacy for exercise was a significant predictor of exercise in the zero model. Severity of motor symptoms was related to frequency of exercise. Self-efficacy contributed to the probability of exercise. Symptom management and improvement of self-efficacy for exercise are important to encourage regular exercise in patients with Parkinson's disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. QNB: differential RNA methylation analysis for count-based small-sample sequencing data with a quad-negative binomial model.

    Science.gov (United States)

    Liu, Lian; Zhang, Shao-Wu; Huang, Yufei; Meng, Jia

    2017-08-31

    As a newly emerged research area, RNA epigenetics has drawn increasing attention recently for the participation of RNA methylation and other modifications in a number of crucial biological processes. Thanks to high throughput sequencing techniques, such as, MeRIP-Seq, transcriptome-wide RNA methylation profile is now available in the form of count-based data, with which it is often of interests to study the dynamics at epitranscriptomic layer. However, the sample size of RNA methylation experiment is usually very small due to its costs; and additionally, there usually exist a large number of genes whose methylation level cannot be accurately estimated due to their low expression level, making differential RNA methylation analysis a difficult task. We present QNB, a statistical approach for differential RNA methylation analysis with count-based small-sample sequencing data. Compared with previous approaches such as DRME model based on a statistical test covering the IP samples only with 2 negative binomial distributions, QNB is based on 4 independent negative binomial distributions with their variances and means linked by local regressions, and in the way, the input control samples are also properly taken care of. In addition, different from DRME approach, which relies only the input control sample only for estimating the background, QNB uses a more robust estimator for gene expression by combining information from both input and IP samples, which could largely improve the testing performance for very lowly expressed genes. QNB showed improved performance on both simulated and real MeRIP-Seq datasets when compared with competing algorithms. And the QNB model is also applicable to other datasets related RNA modifications, including but not limited to RNA bisulfite sequencing, m 1 A-Seq, Par-CLIP, RIP-Seq, etc.

  11. Prediction of province-level outbreaks of foot-and-mouth disease in Iran using a zero-inflated negative binomial model.

    Science.gov (United States)

    Jafarzadeh, S Reza; Norris, Michelle; Thurmond, Mark C

    2014-08-01

    To identify events that could predict province-level frequency of foot-and-mouth disease (FMD) outbreaks in Iran, 5707 outbreaks reported from April 1995 to March 2002 were studied. A zero-inflated negative binomial model was used to estimate the probability of a 'no-outbreak' status and the number of outbreaks in a province, using the number of previous occurrences of FMD for the same or adjacent provinces and season as covariates. For each province, the probability of observing no outbreak was negatively associated with the number of outbreaks in the same province in the previous month (odds ratio [OR]=0.06, 95% confidence interval [CI]: 0.01, 0.30) and in 'the second previous month' (OR=0.10, 95% CI: 0.02, 0.51), the total number of outbreaks in the second previous month in adjacent provinces (OR=0.57, 95% CI: 0.36, 0.91) and the season (winter [OR=0.18, 95% CI: 0.06, 0.55] and spring [OR=0.27, 95% CI: 0.09, 0.81], compared with summer). The expected number of outbreaks in a province was positively associated with number of outbreaks in the same province in previous month (coefficient [coef]=0.74, 95% CI: 0.66, 0.82) and in the second previous month (coef=0.23, 95% CI: 0.16, 0.31), total number of outbreaks in adjacent provinces in the previous month (coef=0.32, 95% CI: 0.22, 0.41) and season (fall [coef=0.20, 95% CI: 0.07, 0.33] and spring [coef=0.18, 95% CI: 0.05, 0.31], compared to summer); however, number of outbreaks was negatively associated with the total number of outbreaks in adjacent provinces in the second previous month (coef=-0.19, 95% CI: -0.28, -0.09). The findings indicate that the probability of an outbreak (and the expected number of outbreaks if any) may be predicted based on previous province information, which could help decision-makers allocate resources more efficiently for province-level disease control measures. Further, the study illustrates use of zero inflated negative binomial model to study diseases occurrence where disease is

  12. Application of a random effects negative binomial model to examine tram-involved crash frequency on route sections in Melbourne, Australia.

    Science.gov (United States)

    Naznin, Farhana; Currie, Graham; Logan, David; Sarvi, Majid

    2016-07-01

    Safety is a key concern in the design, operation and development of light rail systems including trams or streetcars as they impose crash risks on road users in terms of crash frequency and severity. The aim of this study is to identify key traffic, transit and route factors that influence tram-involved crash frequencies along tram route sections in Melbourne. A random effects negative binomial (RENB) regression model was developed to analyze crash frequency data obtained from Yarra Trams, the tram operator in Melbourne. The RENB modelling approach can account for spatial and temporal variations within observation groups in panel count data structures by assuming that group specific effects are randomly distributed across locations. The results identify many significant factors effecting tram-involved crash frequency including tram service frequency (2.71), tram stop spacing (-0.42), tram route section length (0.31), tram signal priority (-0.25), general traffic volume (0.18), tram lane priority (-0.15) and ratio of platform tram stops (-0.09). Findings provide useful insights on route section level tram-involved crashes in an urban tram or streetcar operating environment. The method described represents a useful planning tool for transit agencies hoping to improve safety performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Prediction of vehicle crashes by drivers' characteristics and past traffic violations in Korea using a zero-inflated negative binomial model.

    Science.gov (United States)

    Kim, Dae-Hwan; Ramjan, Lucie M; Mak, Kwok-Kei

    2016-01-01

    Traffic safety is a significant public health challenge, and vehicle crashes account for the majority of injuries. This study aims to identify whether drivers' characteristics and past traffic violations may predict vehicle crashes in Korea. A total of 500,000 drivers were randomly selected from the 11.6 million driver records of the Ministry of Land, Transport and Maritime Affairs in Korea. Records of traffic crashes were obtained from the archives of the Korea Insurance Development Institute. After matching the past violation history for the period 2004-2005 with the number of crashes in year 2006, a total of 488,139 observations were used for the analysis. Zero-inflated negative binomial model was used to determine the incident risk ratio (IRR) of vehicle crashes by past violations of individual drivers. The included covariates were driver's age, gender, district of residence, vehicle choice, and driving experience. Drivers violating (1) a hit-and-run or drunk driving regulation at least once and (2) a signal, central line, or speed regulation more than once had a higher risk of a vehicle crash with respective IRRs of 1.06 and 1.15. Furthermore, female gender, a younger age, fewer years of driving experience, and middle-sized vehicles were all significantly associated with a higher likelihood of vehicle crashes. Drivers' demographic characteristics and past traffic violations could predict vehicle crashes in Korea. Greater resources should be assigned to the provision of traffic safety education programs for the high-risk driver groups.

  14. CUMBIN - CUMULATIVE BINOMIAL PROGRAMS

    Science.gov (United States)

    Bowerman, P. N.

    1994-01-01

    The cumulative binomial program, CUMBIN, is one of a set of three programs which calculate cumulative binomial probability distributions for arbitrary inputs. The three programs, CUMBIN, NEWTONP (NPO-17556), and CROSSER (NPO-17557), can be used independently of one another. CUMBIN can be used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. The program has been used for reliability/availability calculations. CUMBIN calculates the probability that a system of n components has at least k operating if the probability that any one operating is p and the components are independent. Equivalently, this is the reliability of a k-out-of-n system having independent components with common reliability p. CUMBIN can evaluate the incomplete beta distribution for two positive integer arguments. CUMBIN can also evaluate the cumulative F distribution and the negative binomial distribution, and can determine the sample size in a test design. CUMBIN is designed to work well with all integer values 0 < k <= n. To run the program, the user simply runs the executable version and inputs the information requested by the program. The program is not designed to weed out incorrect inputs, so the user must take care to make sure the inputs are correct. Once all input has been entered, the program calculates and lists the result. The CUMBIN program is written in C. It was developed on an IBM AT with a numeric co-processor using Microsoft C 5.0. Because the source code is written using standard C structures and functions, it should compile correctly with most C compilers. The program format is interactive. It has been implemented under DOS 3.2 and has a memory requirement of 26K. CUMBIN was developed in 1988.

  15. Bipartite binomial heaps

    DEFF Research Database (Denmark)

    Elmasry, Amr; Jensen, Claus; Katajainen, Jyrki

    2017-01-01

    the (total) number of elements stored in the data structure(s) prior to the operation. As the resulting data structure consists of two components that are different variants of binomial heaps, we call it a bipartite binomial heap. Compared to its counterpart, a multipartite binomial heap, the new structure...

  16. [Experience of non-reversible and reversible carious lesions in 11 and 12 years old Mexican schoolchildren: a negative binomial regression analysis].

    Science.gov (United States)

    Villalobos-Rodelo, Juan J; Medina-Solís, Carlo E; Verdugo-Barraza, Lourdes; Islas-Granillo, Horacio; García-Jau, Rosa A; Escoffié-Ramírez, Mauricio; Maupomé, Gerardo

    2013-01-01

    Dental caries is one of the most common chronic childhood diseases worldwide. In Mexico it is a public health problem. To identify variables associated with caries occurrence (non-reversible and reversible lesions) in a sample of Mexican schoolchildren. We performed a cross-sectional study in 640 schoolchildren of 11 and 12 years of age. The dependent variable was the D 1+2 MFT index, comprising reversible and irreversible carious lesions (dental caries) according to the Pitts D 1 /D 2 classification. Clinical examinations were performed by trained and standardized examiners. Using structured questionnaires we collected socio-demographic, socio-economic and health-related oral behaviors. Negative binomial regression was used for the analysis. The D 1+2 MFT index was 5.68±3.47. The schoolchildren characteristics associated with an increase in the expected average rate of dental caries were: being female (27.1%), having 12 years of age (23.2%), consuming larger amounts of sugar (13.9%), having mediocre (31.3%) and poor/very poor oral hygiene (62.3%). Conversely, when the family owned a car the expected mean D 1+2 MFT decreased 13.5%. When dental caries occurrence (about 6 decayed teeth) is estimated taking into consideration not only cavities (lesions in need of restorative dental treatment) but also incipient carious lesions, the character of this disease as a common clinical problem and as a public health problem are further emphasized. Results revealed the need to establish preventive and curative strategies in the sample.

  17. A semiparametric negative binomial generalized linear model for modeling over-dispersed count data with a heavy tail: Characteristics and applications to crash data.

    Science.gov (United States)

    Shirazi, Mohammadali; Lord, Dominique; Dhavala, Soma Sekhar; Geedipally, Srinivas Reddy

    2016-06-01

    Crash data can often be characterized by over-dispersion, heavy (long) tail and many observations with the value zero. Over the last few years, a small number of researchers have started developing and applying novel and innovative multi-parameter models to analyze such data. These multi-parameter models have been proposed for overcoming the limitations of the traditional negative binomial (NB) model, which cannot handle this kind of data efficiently. The research documented in this paper continues the work related to multi-parameter models. The objective of this paper is to document the development and application of a flexible NB generalized linear model with randomly distributed mixed effects characterized by the Dirichlet process (NB-DP) to model crash data. The objective of the study was accomplished using two datasets. The new model was compared to the NB and the recently introduced model based on the mixture of the NB and Lindley (NB-L) distributions. Overall, the research study shows that the NB-DP model offers a better performance than the NB model once data are over-dispersed and have a heavy tail. The NB-DP performed better than the NB-L when the dataset has a heavy tail, but a smaller percentage of zeros. However, both models performed similarly when the dataset contained a large amount of zeros. In addition to a greater flexibility, the NB-DP provides a clustering by-product that allows the safety analyst to better understand the characteristics of the data, such as the identification of outliers and sources of dispersion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. A flexible mixed-effect negative binomial regression model for detecting unusual increases in MRI lesion counts in individual multiple sclerosis patients.

    Science.gov (United States)

    Kondo, Yumi; Zhao, Yinshan; Petkau, John

    2015-06-15

    We develop a new modeling approach to enhance a recently proposed method to detect increases of contrast-enhancing lesions (CELs) on repeated magnetic resonance imaging, which have been used as an indicator for potential adverse events in multiple sclerosis clinical trials. The method signals patients with unusual increases in CEL activity by estimating the probability of observing CEL counts as large as those observed on a patient's recent scans conditional on the patient's CEL counts on previous scans. This conditional probability index (CPI), computed based on a mixed-effect negative binomial regression model, can vary substantially depending on the choice of distribution for the patient-specific random effects. Therefore, we relax this parametric assumption to model the random effects with an infinite mixture of beta distributions, using the Dirichlet process, which effectively allows any form of distribution. To our knowledge, no previous literature considers a mixed-effect regression for longitudinal count variables where the random effect is modeled with a Dirichlet process mixture. As our inference is in the Bayesian framework, we adopt a meta-analytic approach to develop an informative prior based on previous clinical trials. This is particularly helpful at the early stages of trials when less data are available. Our enhanced method is illustrated with CEL data from 10 previous multiple sclerosis clinical trials. Our simulation study shows that our procedure estimates the CPI more accurately than parametric alternatives when the patient-specific random effect distribution is misspecified and that an informative prior improves the accuracy of the CPI estimates. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Chain binomial models and binomial autoregressive processes.

    Science.gov (United States)

    Weiss, Christian H; Pollett, Philip K

    2012-09-01

    We establish a connection between a class of chain-binomial models of use in ecology and epidemiology and binomial autoregressive (AR) processes. New results are obtained for the latter, including expressions for the lag-conditional distribution and related quantities. We focus on two types of chain-binomial model, extinction-colonization and colonization-extinction models, and present two approaches to parameter estimation. The asymptotic distributions of the resulting estimators are studied, as well as their finite-sample performance, and we give an application to real data. A connection is made with standard AR models, which also has implications for parameter estimation. © 2011, The International Biometric Society.

  20. An empirical tool to evaluate the safety of cyclists: Community based, macro-level collision prediction models using negative binomial regression.

    Science.gov (United States)

    Wei, Feng; Lovegrove, Gordon

    2013-12-01

    Today, North American governments are more willing to consider compact neighborhoods with increased use of sustainable transportation modes. Bicycling, one of the most effective modes for short trips with distances less than 5km is being encouraged. However, as vulnerable road users (VRUs), cyclists are more likely to be injured when involved in collisions. In order to create a safe road environment for them, evaluating cyclists' road safety at a macro level in a proactive way is necessary. In this paper, different generalized linear regression methods for collision prediction model (CPM) development are reviewed and previous studies on micro-level and macro-level bicycle-related CPMs are summarized. On the basis of insights gained in the exploration stage, this paper also reports on efforts to develop negative binomial models for bicycle-auto collisions at a community-based, macro-level. Data came from the Central Okanagan Regional District (CORD), of British Columbia, Canada. The model results revealed two types of statistical associations between collisions and each explanatory variable: (1) An increase in bicycle-auto collisions is associated with an increase in total lane kilometers (TLKM), bicycle lane kilometers (BLKM), bus stops (BS), traffic signals (SIG), intersection density (INTD), and arterial-local intersection percentage (IALP). (2) A decrease in bicycle collisions was found to be associated with an increase in the number of drive commuters (DRIVE), and in the percentage of drive commuters (DRP). These results support our hypothesis that in North America, with its current low levels of bicycle use (<4%), we can initially expect to see an increase in bicycle collisions as cycle mode share increases. However, as bicycle mode share increases beyond some unknown 'critical' level, our hypothesis also predicts a net safety improvement. To test this hypothesis and to further explore the statistical relationships between bicycle mode split and overall road

  1. Binomial collisions and near collisions

    OpenAIRE

    Blokhuis, Aart; Brouwer, Andries; de Weger, Benne

    2017-01-01

    We describe efficient algorithms to search for cases in which binomial coefficients are equal or almost equal, give a conjecturally complete list of all cases where two binomial coefficients differ by 1, and give some identities for binomial coefficients that seem to be new.

  2. CROSSER - CUMULATIVE BINOMIAL PROGRAMS

    Science.gov (United States)

    Bowerman, P. N.

    1994-01-01

    The cumulative binomial program, CROSSER, is one of a set of three programs which calculate cumulative binomial probability distributions for arbitrary inputs. The three programs, CROSSER, CUMBIN (NPO-17555), and NEWTONP (NPO-17556), can be used independently of one another. CROSSER can be used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. The program has been used for reliability/availability calculations. CROSSER calculates the point at which the reliability of a k-out-of-n system equals the common reliability of the n components. It is designed to work well with all integer values 0 < k <= n. To run the program, the user simply runs the executable version and inputs the information requested by the program. The program is not designed to weed out incorrect inputs, so the user must take care to make sure the inputs are correct. Once all input has been entered, the program calculates and lists the result. It also lists the number of iterations of Newton's method required to calculate the answer within the given error. The CROSSER program is written in C. It was developed on an IBM AT with a numeric co-processor using Microsoft C 5.0. Because the source code is written using standard C structures and functions, it should compile correctly with most C compilers. The program format is interactive. It has been implemented under DOS 3.2 and has a memory requirement of 26K. CROSSER was developed in 1988.

  3. Negative binomial distribution fits to multiplicity distributions is restricted δη intervals from central O+Cu collisions at 14.6A GeV/c and their implication for open-quotes Intermittencyclose quotes

    International Nuclear Information System (INIS)

    Tannenbaum, M.J.

    1993-01-01

    Experience in analyzing the data from Light and Heavy Ion Collisions in terms of distributions rather than moments suggests that conventional fluctuations of multiplicity and transverse energy can be well described by Gamma or Negative Binomial Distributions (NBD). Multiplicity distributions were obtained for central 16 O+Cu collisions in bins of δη= 0.1,0.2, 0.3 .... 0.5,1.0, where the bin of 1.0 covers 1.2 < η < 2.2 in the laboratory. NBD fits were performed to these distributions with excellent results in all δη bins. The κ parameter of the NBD fit increases linearly with the δη interval, which is a totally unexpected and particularly striking result. Due to the well known property of the NBD under convolution, this result indicates that the multiplicity distributions in adjacent bins of pseudorapidity δη ∼ 0.1 are largely statistically independent. The relationship to 2-particle correlations and open-quotes Intermittencyclose quotes will be discussed

  4. NEWTONP - CUMULATIVE BINOMIAL PROGRAMS

    Science.gov (United States)

    Bowerman, P. N.

    1994-01-01

    The cumulative binomial program, NEWTONP, is one of a set of three programs which calculate cumulative binomial probability distributions for arbitrary inputs. The three programs, NEWTONP, CUMBIN (NPO-17555), and CROSSER (NPO-17557), can be used independently of one another. NEWTONP can be used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. The program has been used for reliability/availability calculations. NEWTONP calculates the probably p required to yield a given system reliability V for a k-out-of-n system. It can also be used to determine the Clopper-Pearson confidence limits (either one-sided or two-sided) for the parameter p of a Bernoulli distribution. NEWTONP can determine Bayesian probability limits for a proportion (if the beta prior has positive integer parameters). It can determine the percentiles of incomplete beta distributions with positive integer parameters. It can also determine the percentiles of F distributions and the midian plotting positions in probability plotting. NEWTONP is designed to work well with all integer values 0 < k <= n. To run the program, the user simply runs the executable version and inputs the information requested by the program. NEWTONP is not designed to weed out incorrect inputs, so the user must take care to make sure the inputs are correct. Once all input has been entered, the program calculates and lists the result. It also lists the number of iterations of Newton's method required to calculate the answer within the given error. The NEWTONP program is written in C. It was developed on an IBM AT with a numeric co-processor using Microsoft C 5.0. Because the source code is written using standard C structures and functions, it should compile correctly with most C compilers. The program format is interactive. It has been implemented under DOS 3.2 and has a memory requirement of 26K. NEWTONP was developed in 1988.

  5. Hurdles in Basic Science Translation

    Directory of Open Access Journals (Sweden)

    Christina J. Perry

    2017-07-01

    Full Text Available In the past century there have been incredible advances in the field of medical research, but what hinders translation of this knowledge into effective treatment for human disease? There is an increasing focus on the failure of many research breakthroughs to be translated through the clinical trial process and into medical practice. In this mini review, we will consider some of the reasons that findings in basic medical research fail to become translated through clinical trials and into basic medical practices. We focus in particular on the way that human disease is modeled, the understanding we have of how our targets behave in vivo, and also some of the issues surrounding reproducibility of basic research findings. We will also look at some of the ways that have been proposed for overcoming these issues. It appears that there needs to be a cultural shift in the way we fund, publish and recognize quality control in scientific research. Although this is a daunting proposition, we hope that with increasing awareness and focus on research translation and the hurdles that impede it, the field of medical research will continue to inform and improve medical practice across the world.

  6. Binomial Rings: Axiomatisation, Transfer and Classification

    OpenAIRE

    Xantcha, Qimh Richey

    2011-01-01

    Hall's binomial rings, rings with binomial coefficients, are given an axiomatisation and proved identical to the numerical rings studied by Ekedahl. The Binomial Transfer Principle is established, enabling combinatorial proofs of algebraical identities. The finitely generated binomial rings are completely classified. An application to modules over binomial rings is given.

  7. On a Fractional Binomial Process

    Science.gov (United States)

    Cahoy, Dexter O.; Polito, Federico

    2012-02-01

    The classical binomial process has been studied by Jakeman (J. Phys. A 23:2815-2825, 1990) (and the references therein) and has been used to characterize a series of radiation states in quantum optics. In particular, he studied a classical birth-death process where the chance of birth is proportional to the difference between a larger fixed number and the number of individuals present. It is shown that at large times, an equilibrium is reached which follows a binomial process. In this paper, the classical binomial process is generalized using the techniques of fractional calculus and is called the fractional binomial process. The fractional binomial process is shown to preserve the binomial limit at large times while expanding the class of models that include non-binomial fluctuations (non-Markovian) at regular and small times. As a direct consequence, the generality of the fractional binomial model makes the proposed model more desirable than its classical counterpart in describing real physical processes. More statistical properties are also derived.

  8. The Binomial Distribution in Shooting

    Science.gov (United States)

    Chalikias, Miltiadis S.

    2009-01-01

    The binomial distribution is used to predict the winner of the 49th International Shooting Sport Federation World Championship in double trap shooting held in 2006 in Zagreb, Croatia. The outcome of the competition was definitely unexpected.

  9. Examining systemic steroid Use in older inflammatory bowel disease patients using hurdle models: a cohort study.

    Science.gov (United States)

    Johnson, Sophia L; Palta, Mari; Bartels, Christie M; Thorpe, Carolyn T; Weiss, Jennifer M; Smith, Maureen A

    2015-12-08

    Interpreting clinical guideline adherence and the appropriateness of medication regimens requires consideration of individual patient and caregiver factors. Factors leading to initiation of a medication may differ from those determining continued use. We believe this is the case for systemic steroid therapy in inflammatory bowel disease (IBD), resulting in a need to apply methods that separately consider factors associated with initiation and duration of therapy. To evaluate the relationship between patient characteristics and the frequency and duration of incident steroid use we apply a 2-part hurdle model to Medicare data. We do so in older patients with tumor necrosis factor antagonist (anti-TNFs) contraindications, as they are of special interest for compliance with Medicare-adopted, quality metrics calling for anti-TNFs and nonbiologic immune therapies to reduce steroid utilization. Many older patients have contraindications to anti-TNFs. However, nonbiologics cause adverse events that are concerning in older adults, limiting their use in this population and increasing reliance on systemic steroids. We used a national Medicare sample for 2006-2009 including patients with 12 months or greater of Parts A and B and 6 months or greater of Part D coverage, IBD confirmed with at least 2 claims for ICD-9CM 555.xx or 556.xx, anti-TNF contraindications and without contraindications to nonbiologic agents. We applied a negative binomial-logit hurdle model to examine patient characteristics associated with systemic steroid utilization. Among the 1,216 IBD patients without baseline steroid use, 21% used systemic steroids. Odds of receiving systemic steroids were greater in those younger, rural, and those receiving other agents. Available patient characteristics failed to predict longer steroid treatment duration. Our study identified differences in predictors of frequency and duration of medication use and suggests the utility of two-part models to examine drug utilization

  10. Defining the critical hurdles in cancer immunotherapy

    DEFF Research Database (Denmark)

    Fox, Bernard A; Schendel, Dolores J; Butterfield, Lisa H

    2011-01-01

    into early stage clinical trials as quickly as it is safe, and if successful, these therapies should efficiently obtain regulatory approval and widespread clinical application. In late 2009 and 2010 the Society for Immunotherapy of Cancer (SITC), convened an "Immunotherapy Summit" with representatives from...... companies and academic institutions to facilitate changes necessary to accelerate clinical translation of novel immune-based cancer therapies. The critical hurdles identified by representatives of the collaborating organizations, now organized as the World Immunotherapy Council, are presented and discussed...... in this report. Some of the identified hurdles impede all investigators; others hinder investigators only in certain regions or institutions or are more relevant to specific types of immunotherapy or first-in-humans studies. Each of these hurdles can significantly delay clinical translation of promising advances...

  11. Race Pattern of Women’s 100-m Hurdles: Time Analysis of Olympic Hurdle Performance

    Directory of Open Access Journals (Sweden)

    Athanasios Tsiokanos

    2017-07-01

    Full Text Available Background: For control and effective management of training process in women’s 100-m hurdles event, the coaches, in addition to detailed biomechanical parameters, need also overall, more comprehensive technical parameters, called direct performance descriptors which are used for planning the distribution of an athlete’s efforts over the race. Purpose: The aim of this study was the investigation of the race behavior of elite women sprint hurdlers, on the basis of selected time parameters, and the examination of the existence of a common race pattern in high level hurdle performance. Method: The time data of the race performance between two consecutive Olympic Games were compared. The analyzing subjects consisted of all women 100-m hurdle finalists in Athens 2004 (n = 6 and all women 100-m hurdle finalists (n = 8 and semi-finalists (n = 14 in Beijing 2008. Results: No significant differences were revealed between the two competitions concerning to the means of approach run time, run-in time, intermediate touchdown times, interval times for the hurdle units and the corresponding average velocities. Significant relationship exists between the intermediate times and final performance. The time contribution of the first half of the race to the formation of the final performance is approximately equal to the second one and, generally the standardised time parameters show the existence of a common race pattern in high level hurdle performance. Conclusion: The presented biomechanical data provide coaches and athletes with valuable information about hurdle technique for effective interventions in the training process.

  12. Integer Solutions of Binomial Coefficients

    Science.gov (United States)

    Gilbertson, Nicholas J.

    2016-01-01

    A good formula is like a good story, rich in description, powerful in communication, and eye-opening to readers. The formula presented in this article for determining the coefficients of the binomial expansion of (x + y)n is one such "good read." The beauty of this formula is in its simplicity--both describing a quantitative situation…

  13. Defining the critical hurdles in cancer immunotherapy.

    Science.gov (United States)

    Fox, Bernard A; Schendel, Dolores J; Butterfield, Lisa H; Aamdal, Steinar; Allison, James P; Ascierto, Paolo Antonio; Atkins, Michael B; Bartunkova, Jirina; Bergmann, Lothar; Berinstein, Neil; Bonorino, Cristina C; Borden, Ernest; Bramson, Jonathan L; Britten, Cedrik M; Cao, Xuetao; Carson, William E; Chang, Alfred E; Characiejus, Dainius; Choudhury, A Raja; Coukos, George; de Gruijl, Tanja; Dillman, Robert O; Dolstra, Harry; Dranoff, Glenn; Durrant, Lindy G; Finke, James H; Galon, Jerome; Gollob, Jared A; Gouttefangeas, Cécile; Grizzi, Fabio; Guida, Michele; Håkansson, Leif; Hege, Kristen; Herberman, Ronald B; Hodi, F Stephen; Hoos, Axel; Huber, Christoph; Hwu, Patrick; Imai, Kohzoh; Jaffee, Elizabeth M; Janetzki, Sylvia; June, Carl H; Kalinski, Pawel; Kaufman, Howard L; Kawakami, Koji; Kawakami, Yutaka; Keilholtz, Ulrich; Khleif, Samir N; Kiessling, Rolf; Kotlan, Beatrix; Kroemer, Guido; Lapointe, Rejean; Levitsky, Hyam I; Lotze, Michael T; Maccalli, Cristina; Maio, Michele; Marschner, Jens-Peter; Mastrangelo, Michael J; Masucci, Giuseppe; Melero, Ignacio; Melief, Cornelius; Murphy, William J; Nelson, Brad; Nicolini, Andrea; Nishimura, Michael I; Odunsi, Kunle; Ohashi, Pamela S; O'Donnell-Tormey, Jill; Old, Lloyd J; Ottensmeier, Christian; Papamichail, Michael; Parmiani, Giorgio; Pawelec, Graham; Proietti, Enrico; Qin, Shukui; Rees, Robert; Ribas, Antoni; Ridolfi, Ruggero; Ritter, Gerd; Rivoltini, Licia; Romero, Pedro J; Salem, Mohamed L; Scheper, Rik J; Seliger, Barbara; Sharma, Padmanee; Shiku, Hiroshi; Singh-Jasuja, Harpreet; Song, Wenru; Straten, Per Thor; Tahara, Hideaki; Tian, Zhigang; van Der Burg, Sjoerd H; von Hoegen, Paul; Wang, Ena; Welters, Marij Jp; Winter, Hauke; Withington, Tara; Wolchok, Jedd D; Xiao, Weihua; Zitvogel, Laurence; Zwierzina, Heinz; Marincola, Francesco M; Gajewski, Thomas F; Wigginton, Jon M; Disis, Mary L

    2011-12-14

    Scientific discoveries that provide strong evidence of antitumor effects in preclinical models often encounter significant delays before being tested in patients with cancer. While some of these delays have a scientific basis, others do not. We need to do better. Innovative strategies need to move into early stage clinical trials as quickly as it is safe, and if successful, these therapies should efficiently obtain regulatory approval and widespread clinical application. In late 2009 and 2010 the Society for Immunotherapy of Cancer (SITC), convened an "Immunotherapy Summit" with representatives from immunotherapy organizations representing Europe, Japan, China and North America to discuss collaborations to improve development and delivery of cancer immunotherapy. One of the concepts raised by SITC and defined as critical by all parties was the need to identify hurdles that impede effective translation of cancer immunotherapy. With consensus on these hurdles, international working groups could be developed to make recommendations vetted by the participating organizations. These recommendations could then be considered by regulatory bodies, governmental and private funding agencies, pharmaceutical companies and academic institutions to facilitate changes necessary to accelerate clinical translation of novel immune-based cancer therapies. The critical hurdles identified by representatives of the collaborating organizations, now organized as the World Immunotherapy Council, are presented and discussed in this report. Some of the identified hurdles impede all investigators; others hinder investigators only in certain regions or institutions or are more relevant to specific types of immunotherapy or first-in-humans studies. Each of these hurdles can significantly delay clinical translation of promising advances in immunotherapy yet if overcome, have the potential to improve outcomes of patients with cancer.

  14. Defining the critical hurdles in cancer immunotherapy

    Directory of Open Access Journals (Sweden)

    Fox Bernard A

    2011-12-01

    Full Text Available Abstract Scientific discoveries that provide strong evidence of antitumor effects in preclinical models often encounter significant delays before being tested in patients with cancer. While some of these delays have a scientific basis, others do not. We need to do better. Innovative strategies need to move into early stage clinical trials as quickly as it is safe, and if successful, these therapies should efficiently obtain regulatory approval and widespread clinical application. In late 2009 and 2010 the Society for Immunotherapy of Cancer (SITC, convened an "Immunotherapy Summit" with representatives from immunotherapy organizations representing Europe, Japan, China and North America to discuss collaborations to improve development and delivery of cancer immunotherapy. One of the concepts raised by SITC and defined as critical by all parties was the need to identify hurdles that impede effective translation of cancer immunotherapy. With consensus on these hurdles, international working groups could be developed to make recommendations vetted by the participating organizations. These recommendations could then be considered by regulatory bodies, governmental and private funding agencies, pharmaceutical companies and academic institutions to facilitate changes necessary to accelerate clinical translation of novel immune-based cancer therapies. The critical hurdles identified by representatives of the collaborating organizations, now organized as the World Immunotherapy Council, are presented and discussed in this report. Some of the identified hurdles impede all investigators; others hinder investigators only in certain regions or institutions or are more relevant to specific types of immunotherapy or first-in-humans studies. Each of these hurdles can significantly delay clinical translation of promising advances in immunotherapy yet if overcome, have the potential to improve outcomes of patients with cancer.

  15. Defining the critical hurdles in cancer immunotherapy

    Science.gov (United States)

    2011-01-01

    Scientific discoveries that provide strong evidence of antitumor effects in preclinical models often encounter significant delays before being tested in patients with cancer. While some of these delays have a scientific basis, others do not. We need to do better. Innovative strategies need to move into early stage clinical trials as quickly as it is safe, and if successful, these therapies should efficiently obtain regulatory approval and widespread clinical application. In late 2009 and 2010 the Society for Immunotherapy of Cancer (SITC), convened an "Immunotherapy Summit" with representatives from immunotherapy organizations representing Europe, Japan, China and North America to discuss collaborations to improve development and delivery of cancer immunotherapy. One of the concepts raised by SITC and defined as critical by all parties was the need to identify hurdles that impede effective translation of cancer immunotherapy. With consensus on these hurdles, international working groups could be developed to make recommendations vetted by the participating organizations. These recommendations could then be considered by regulatory bodies, governmental and private funding agencies, pharmaceutical companies and academic institutions to facilitate changes necessary to accelerate clinical translation of novel immune-based cancer therapies. The critical hurdles identified by representatives of the collaborating organizations, now organized as the World Immunotherapy Council, are presented and discussed in this report. Some of the identified hurdles impede all investigators; others hinder investigators only in certain regions or institutions or are more relevant to specific types of immunotherapy or first-in-humans studies. Each of these hurdles can significantly delay clinical translation of promising advances in immunotherapy yet if overcome, have the potential to improve outcomes of patients with cancer. PMID:22168571

  16. Improved binomial charts for monitoring high-quality processes

    NARCIS (Netherlands)

    Albers, Willem/Wim

    2009-01-01

    For processes concerning attribute data with (very) small failure rate p, often negative binomial control charts are used. The decision whether to stop or continue is made each time r failures have occurred, for some r≥1. Finding the optimal r for detecting a given increase of p first requires

  17. Improved binomial charts for high-quality processes

    NARCIS (Netherlands)

    Albers, Willem/Wim

    For processes concerning attribute data with (very) small failure rate p, often negative binomial control charts are used. The decision whether to stop or continue is made each time r failures have occurred, for some r≥1. Finding the optimal r for detecting a given increase of p first requires

  18. Smoothness in Binomial Edge Ideals

    Directory of Open Access Journals (Sweden)

    Hamid Damadi

    2016-06-01

    Full Text Available In this paper we study some geometric properties of the algebraic set associated to the binomial edge ideal of a graph. We study the singularity and smoothness of the algebraic set associated to the binomial edge ideal of a graph. Some of these algebraic sets are irreducible and some of them are reducible. If every irreducible component of the algebraic set is smooth we call the graph an edge smooth graph, otherwise it is called an edge singular graph. We show that complete graphs are edge smooth and introduce two conditions such that the graph G is edge singular if and only if it satisfies these conditions. Then, it is shown that cycles and most of trees are edge singular. In addition, it is proved that complete bipartite graphs are edge smooth.

  19. Beta-binomial regression and bimodal utilization.

    Science.gov (United States)

    Liu, Chuan-Fen; Burgess, James F; Manning, Willard G; Maciejewski, Matthew L

    2013-10-01

    To illustrate how the analysis of bimodal U-shaped distributed utilization can be modeled with beta-binomial regression, which is rarely used in health services research. Veterans Affairs (VA) administrative data and Medicare claims in 2001-2004 for 11,123 Medicare-eligible VA primary care users in 2000. We compared means and distributions of VA reliance (the proportion of all VA/Medicare primary care visits occurring in VA) predicted from beta-binomial, binomial, and ordinary least-squares (OLS) models. Beta-binomial model fits the bimodal distribution of VA reliance better than binomial and OLS models due to the nondependence on normality and the greater flexibility in shape parameters. Increased awareness of beta-binomial regression may help analysts apply appropriate methods to outcomes with bimodal or U-shaped distributions. © Health Research and Educational Trust.

  20. PENERAPAN REGRESI BINOMIAL NEGATIF UNTUK MENGATASI OVERDISPERSI PADA REGRESI POISSON

    Directory of Open Access Journals (Sweden)

    PUTU SUSAN PRADAWATI

    2013-09-01

    Full Text Available Poisson regression was used to analyze the count data which Poisson distributed. Poisson regression analysis requires state equidispersion, in which the mean value of the response variable is equal to the value of the variance. However, there are deviations in which the value of the response variable variance is greater than the mean. This is called overdispersion. If overdispersion happens and Poisson Regression analysis is being used, then underestimated standard errors will be obtained. Negative Binomial Regression can handle overdispersion because it contains a dispersion parameter. From the simulation data which experienced overdispersion in the Poisson Regression model it was found that the Negative Binomial Regression was better than the Poisson Regression model.

  1. Artificial insemination history: hurdles and milestones.

    Science.gov (United States)

    Ombelet, W; Van Robays, J

    2015-01-01

    Artificial insemination with homologous (AIH) or donor semen (AID) is nowadays a very popular treatment procedure used for many subfertile women worldwide. The rationale behind artificial insemination is to increase gamete density at the site of fertilisation. The sequence of events leading to today's common use of artificial insemination traces back to scientific studies and experimentation many centuries ago. Modern techniques used in human artificial insemination programmes are mostly adapted from the work on cattle by dairy farmers wishing to improve milk production by using artificial insemination with sperm of selected bulls with well chosen genetic traits. The main reason for the renewed interest in artificial insemination in human was associated with the refinement of techniques for the preparation of washed motile spermatozoa in the early years of IVF. The history of artificial insemination is reviewed with particular interest to the most important hurdles and milestones.

  2. Polymer welding with lasers: chances and hurdles

    Science.gov (United States)

    Bachmann, Friedrich G.

    2002-02-01

    Polymer welding with lasers has been demonstrated already several years ago, using preferably CO2 and Nd:YAG lasers; however, it did not become a big market so far, which is commonly accepted to be due to cost reasons and the size of the laser systems. With the appearance of the efficient, reliable, extremely compact and easy to integrate high power diode lasers, this technology undergoes a renaissance and first application in industrial manufacturing environment have been reported. However, our experience has also shown, that technological hurdles still exclude certain applications and limit the technology to certain configurations. This is, since additionally to the material parameters of the polymer for conventional welding, e.g. melting resp. glass temperature, decomposition temperature, thermal expansion coefficient etc. for the laser weld of course optical parameters play a key role.

  3. Artificial insemination history: hurdles and milestones

    Science.gov (United States)

    Ombelet, W.; Van Robays, J.

    2015-01-01

    Artificial insemination with homologous (AIH) or donor semen (AID) is nowadays a very popular treatment procedure used for many subfertile women worldwide. The rationale behind artificial insemination is to increase gamete density at the site of fertilisation. The sequence of events leading to today’s common use of artificial insemination traces back to scientific studies and experimentation many centuries ago. Modern techniques used in human artificial insemination programmes are mostly adapted from the work on cattle by dairy farmers wishing to improve milk production by using artificial insemination with sperm of selected bulls with well chosen genetic traits. The main reason for the renewed interest in artificial insemination in human was associated with the refinement of techniques for the preparation of washed motile spermatozoa in the early years of IVF. The history of artificial insemination is reviewed with particular interest to the most important hurdles and milestones. PMID:26175891

  4. System-Reliability Cumulative-Binomial Program

    Science.gov (United States)

    Scheuer, Ernest M.; Bowerman, Paul N.

    1989-01-01

    Cumulative-binomial computer program, NEWTONP, one of set of three programs, calculates cumulative binomial probability distributions for arbitrary inputs. NEWTONP, CUMBIN (NPO-17555), and CROSSER (NPO-17557), used independently of one another. Program finds probability required to yield given system reliability. Used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. Program written in C.

  5. A class of orthogonal nonrecursive binomial filters.

    Science.gov (United States)

    Haddad, R. A.

    1971-01-01

    The time- and frequency-domain properties of the orthogonal binomial sequences are presented. It is shown that these sequences, or digital filters based on them, can be generated using adders and delay elements only. The frequency-domain behavior of these nonrecursive binomial filters suggests a number of applications as low-pass Gaussian filters or as inexpensive bandpass filters.

  6. Common-Reliability Cumulative-Binomial Program

    Science.gov (United States)

    Scheuer, Ernest, M.; Bowerman, Paul N.

    1989-01-01

    Cumulative-binomial computer program, CROSSER, one of set of three programs, calculates cumulative binomial probability distributions for arbitrary inputs. CROSSER, CUMBIN (NPO-17555), and NEWTONP (NPO-17556), used independently of one another. Point of equality between reliability of system and common reliability of components found. Used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. Program written in C.

  7. Problems on Divisibility of Binomial Coefficients

    Science.gov (United States)

    Osler, Thomas J.; Smoak, James

    2004-01-01

    Twelve unusual problems involving divisibility of the binomial coefficients are represented in this article. The problems are listed in "The Problems" section. All twelve problems have short solutions which are listed in "The Solutions" section. These problems could be assigned to students in any course in which the binomial theorem and Pascal's…

  8. Predicting Cumulative Incidence Probability by Direct Binomial Regression

    DEFF Research Database (Denmark)

    Scheike, Thomas H.; Zhang, Mei-Jie

    Binomial modelling; cumulative incidence probability; cause-specific hazards; subdistribution hazard......Binomial modelling; cumulative incidence probability; cause-specific hazards; subdistribution hazard...

  9. Correlated binomial models and correlation structures

    International Nuclear Information System (INIS)

    Hisakado, Masato; Kitsukawa, Kenji; Mori, Shintaro

    2006-01-01

    We discuss a general method to construct correlated binomial distributions by imposing several consistent relations on the joint probability function. We obtain self-consistency relations for the conditional correlations and conditional probabilities. The beta-binomial distribution is derived by a strong symmetric assumption on the conditional correlations. Our derivation clarifies the 'correlation' structure of the beta-binomial distribution. It is also possible to study the correlation structures of other probability distributions of exchangeable (homogeneous) correlated Bernoulli random variables. We study some distribution functions and discuss their behaviours in terms of their correlation structures

  10. Examining Teachers' Hurdles to `Science for All'

    Science.gov (United States)

    Southerland, Sherry; Gallard, Alejandro; Callihan, Laurie

    2011-11-01

    The goal of this research is to identify science teachers' beliefs and conceptions that play an important role in shaping their understandings of and attempts to enact inclusive science teaching practices. We examined the work products, both informal (online discussions, email exchanges) and formal (papers, unit plans, peer reviews), of 14 teachers enrolled in a master's degree course focused on diversity in science teaching and learning. These emerging understandings were member-checked via a series of interviews with a subset of these teachers. Our analysis was conducted in two stages: (1) describing the difficulties the teachers identified for themselves in their attempts to teach science to a wide range of students in their classes and (2) analyzing these self-identified barriers for underlying beliefs and conceptions that serve to prohibit or allow for the teachers' understanding and enactment of equitable science instruction. The teachers' self-identified barriers were grouped into three categories: students, broader social infrastructure, and self. The more fundamental barriers identified included teacher beliefs about the ethnocentrism of the mainstream, essentialism/individualism, and beliefs about the meritocracy of schooling. The implications of these hurdles for science teacher education are discussed.

  11. Tohoku Women's Hurdling Project: Science Angels (abstract)

    Science.gov (United States)

    Mizuki, Kotoe; Watanabe, Mayuko

    2009-04-01

    Tohoku University was the first National University to admit three women students in Japan in 1913. To support the university's traditional ``open-door'' policy, various projects have been promoted throughout the university since its foundation. A government plan, the Third-Stage Basic Plan for Science and Technology, aims to increase the women scientist ratio up to 25% nationwide. In order to achieve this goal, the Tohoku Women's Hurdling Project, funded by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), was adopted in 2006. This project is threefold: support for child/family, improvement of facilities, and support for the next generation, which includes our Science Angels program. ``Science Angels'' are women PhD students appointed by the university president, with the mission to form a strong support system among each other and to become role-models to inspire younger students who want to become researchers. Currently, 50 women graduate students of the natural sciences are Science Angels and are encouraged to design and deliver lectures in their areas of specialty at their alma maters. Up to now, 12 lectures have been delivered and science events for children in our community have been held-all with great success.

  12. Newton Binomial Formulas in Schubert Calculus

    OpenAIRE

    Cordovez, Jorge; Gatto, Letterio; Santiago, Taise

    2008-01-01

    We prove Newton's binomial formulas for Schubert Calculus to determine numbers of base point free linear series on the projective line with prescribed ramification divisor supported at given distinct points.

  13. Calculating Cumulative Binomial-Distribution Probabilities

    Science.gov (United States)

    Scheuer, Ernest M.; Bowerman, Paul N.

    1989-01-01

    Cumulative-binomial computer program, CUMBIN, one of set of three programs, calculates cumulative binomial probability distributions for arbitrary inputs. CUMBIN, NEWTONP (NPO-17556), and CROSSER (NPO-17557), used independently of one another. Reliabilities and availabilities of k-out-of-n systems analyzed. Used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. Used for calculations of reliability and availability. Program written in C.

  14. Effect of Hurdle Technology in Food Preservation: A Review.

    Science.gov (United States)

    Singh, Shiv; Shalini, Rachana

    2016-01-01

    Hurdle technology is used in industrialized as well as in developing countries for the gentle but effective preservation of foods. Hurdle technology was developed several years ago as a new concept for the production of safe, stable, nutritious, tasty, and economical foods. Previously hurdle technology, i.e., a combination of preservation methods, was used empirically without much knowledge of the governing principles. The intelligent application of hurdle technology has become more prevalent now, because the principles of major preservative factors for foods (e.g., temperature, pH, aw, Eh, competitive flora), and their interactions, became better known. Recently, the influence of food preservation methods on the physiology and behavior of microorganisms in foods, i.e. their homeostasis, metabolic exhaustion, stress reactions, are taken into account, and the novel concept of multi-target food preservation emerged. The present contribution reviews the concept of the potential hurdles for foods, the hurdle effect, and the hurdle technology for the prospects of the future goal of a multi-target preservation of foods.

  15. Log-binomial models: exploring failed convergence.

    Science.gov (United States)

    Williamson, Tyler; Eliasziw, Misha; Fick, Gordon Hilton

    2013-12-13

    Relative risk is a summary metric that is commonly used in epidemiological investigations. Increasingly, epidemiologists are using log-binomial models to study the impact of a set of predictor variables on a single binary outcome, as they naturally offer relative risks. However, standard statistical software may report failed convergence when attempting to fit log-binomial models in certain settings. The methods that have been proposed in the literature for dealing with failed convergence use approximate solutions to avoid the issue. This research looks directly at the log-likelihood function for the simplest log-binomial model where failed convergence has been observed, a model with a single linear predictor with three levels. The possible causes of failed convergence are explored and potential solutions are presented for some cases. Among the principal causes is a failure of the fitting algorithm to converge despite the log-likelihood function having a single finite maximum. Despite these limitations, log-binomial models are a viable option for epidemiologists wishing to describe the relationship between a set of predictors and a binary outcome where relative risk is the desired summary measure. Epidemiologists are encouraged to continue to use log-binomial models and advocate for improvements to the fitting algorithms to promote the widespread use of log-binomial models.

  16. The Validation of a Beta-Binomial Model for Overdispersed Binomial Data.

    Science.gov (United States)

    Kim, Jongphil; Lee, Ji-Hyun

    2017-01-01

    The beta-binomial model has been widely used as an analytically tractable alternative that captures the overdispersion of an intra-correlated, binomial random variable, X . However, the model validation for X has been rarely investigated. As a beta-binomial mass function takes on a few different shapes, the model validation is examined for each of the classified shapes in this paper. Further, the mean square error (MSE) is illustrated for each shape by the maximum likelihood estimator (MLE) based on a beta-binomial model approach and the method of moments estimator (MME) in order to gauge when and how much the MLE is biased.

  17. Distribution-free Inference of Zero-inated Binomial Data for Longitudinal Studies.

    Science.gov (United States)

    He, H; Wang, W J; Hu, J; Gallop, R; Crits-Christoph, P; Xia, Y L

    2015-10-01

    Count reponses with structural zeros are very common in medical and psychosocial research, especially in alcohol and HIV research, and the zero-inflated poisson (ZIP) and zero-inflated negative binomial (ZINB) models are widely used for modeling such outcomes. However, as alcohol drinking outcomes such as days of drinkings are counts within a given period, their distributions are bounded above by an upper limit (total days in the period) and thus inherently follow a binomial or zero-inflated binomial (ZIB) distribution, rather than a Poisson or zero-inflated Poisson (ZIP) distribution, in the presence of structural zeros. In this paper, we develop a new semiparametric approach for modeling zero-inflated binomial (ZIB)-like count responses for cross-sectional as well as longitudinal data. We illustrate this approach with both simulated and real study data.

  18. Biased binomial assessment of cross-validated estimation of classification accuracies illustrated in diagnosis predictions

    Directory of Open Access Journals (Sweden)

    Quentin Noirhomme

    2014-01-01

    Full Text Available Multivariate classification is used in neuroimaging studies to infer brain activation or in medical applications to infer diagnosis. Their results are often assessed through either a binomial or a permutation test. Here, we simulated classification results of generated random data to assess the influence of the cross-validation scheme on the significance of results. Distributions built from classification of random data with cross-validation did not follow the binomial distribution. The binomial test is therefore not adapted. On the contrary, the permutation test was unaffected by the cross-validation scheme. The influence of the cross-validation was further illustrated on real-data from a brain–computer interface experiment in patients with disorders of consciousness and from an fMRI study on patients with Parkinson disease. Three out of 16 patients with disorders of consciousness had significant accuracy on binomial testing, but only one showed significant accuracy using permutation testing. In the fMRI experiment, the mental imagery of gait could discriminate significantly between idiopathic Parkinson's disease patients and healthy subjects according to the permutation test but not according to the binomial test. Hence, binomial testing could lead to biased estimation of significance and false positive or negative results. In our view, permutation testing is thus recommended for clinical application of classification with cross-validation.

  19. Biased binomial assessment of cross-validated estimation of classification accuracies illustrated in diagnosis predictions.

    Science.gov (United States)

    Noirhomme, Quentin; Lesenfants, Damien; Gomez, Francisco; Soddu, Andrea; Schrouff, Jessica; Garraux, Gaëtan; Luxen, André; Phillips, Christophe; Laureys, Steven

    2014-01-01

    Multivariate classification is used in neuroimaging studies to infer brain activation or in medical applications to infer diagnosis. Their results are often assessed through either a binomial or a permutation test. Here, we simulated classification results of generated random data to assess the influence of the cross-validation scheme on the significance of results. Distributions built from classification of random data with cross-validation did not follow the binomial distribution. The binomial test is therefore not adapted. On the contrary, the permutation test was unaffected by the cross-validation scheme. The influence of the cross-validation was further illustrated on real-data from a brain-computer interface experiment in patients with disorders of consciousness and from an fMRI study on patients with Parkinson disease. Three out of 16 patients with disorders of consciousness had significant accuracy on binomial testing, but only one showed significant accuracy using permutation testing. In the fMRI experiment, the mental imagery of gait could discriminate significantly between idiopathic Parkinson's disease patients and healthy subjects according to the permutation test but not according to the binomial test. Hence, binomial testing could lead to biased estimation of significance and false positive or negative results. In our view, permutation testing is thus recommended for clinical application of classification with cross-validation.

  20. Negative Binomial charts for monitoring high-quality processes

    NARCIS (Netherlands)

    Albers, Willem/Wim

    Good control charts for high quality processes are often based on the number of successes between failures. Geometric charts are simplest in this respect, but slow in recognizing moderately increased failure rates p. Improvement can be achieved by waiting until r > 1 failures have occurred, i.e. by

  1. Application of Negative Binomial Regression for Assessing Public ...

    African Journals Online (AJOL)

    This study investigated the social or demographic factors associated with public awareness of health warnings on the .... television, and in cinemas, newspapers, magazines, billboards, posters in shops and pamphlets. ... demographic and socio-economic factors affecting respondents' awareness of health warnings on the ...

  2. Binomial distribution for the charge asymmetry parameter

    International Nuclear Information System (INIS)

    Chou, T.T.; Yang, C.N.

    1984-01-01

    It is suggested that for high energy collisions the distribution with respect to the charge asymmetry z = nsub(F) - nsub(B) is binomial, where nsub(F) and nsub(B) are the forward and backward charge multiplicities. (orig.)

  3. Binomial test models and item difficulty

    NARCIS (Netherlands)

    van der Linden, Willem J.

    1979-01-01

    In choosing a binomial test model, it is important to know exactly what conditions are imposed on item difficulty. In this paper these conditions are examined for both a deterministic and a stochastic conception of item responses. It appears that they are more restrictive than is generally

  4. Adaptive estimation of binomial probabilities under misclassification

    NARCIS (Netherlands)

    Albers, Willem/Wim; Veldman, H.J.

    1984-01-01

    If misclassification occurs the standard binomial estimator is usually seriously biased. It is known that an improvement can be achieved by using more than one observer in classifying the sample elements. Here it will be investigated which number of observers is optimal given the total number of

  5. Binomial vs poisson statistics in radiation studies

    International Nuclear Information System (INIS)

    Foster, J.; Kouris, K.; Spyrou, N.M.; Matthews, I.P.; Welsh National School of Medicine, Cardiff

    1983-01-01

    The processes of radioactive decay, decay and growth of radioactive species in a radioactive chain, prompt emission(s) from nuclear reactions, conventional activation and cyclic activation are discussed with respect to their underlying statistical density function. By considering the transformation(s) that each nucleus may undergo it is shown that all these processes are fundamentally binomial. Formally, when the number of experiments N is large and the probability of success p is close to zero, the binomial is closely approximated by the Poisson density function. In radiation and nuclear physics, N is always large: each experiment can be conceived of as the observation of the fate of each of the N nuclei initially present. Whether p, the probability that a given nucleus undergoes a prescribed transformation, is close to zero depends on the process and nuclide(s) concerned. Hence, although a binomial description is always valid, the Poisson approximation is not always adequate. Therefore further clarification is provided as to when the binomial distribution must be used in the statistical treatment of detected events. (orig.)

  6. The Normal Distribution From Binomial to Normal

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 6. The Normal Distribution From Binomial to Normal. S Ramasubramanian. Series Article Volume 2 Issue 6 June 1997 pp 15-24. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/06/0015-0024 ...

  7. Adaptive bayesian analysis for binomial proportions

    CSIR Research Space (South Africa)

    Das, Sonali

    2008-10-01

    Full Text Available The authors consider the problem of statistical inference of binomial proportions for non-matched, correlated samples, under the Bayesian framework. Such inference can arise when the same group is observed at a different number of times with the aim...

  8. Longitudinal beta-binomial modeling using GEE for overdispersed binomial data.

    Science.gov (United States)

    Wu, Hongqian; Zhang, Ying; Long, Jeffrey D

    2017-03-15

    Longitudinal binomial data are frequently generated from multiple questionnaires and assessments in various scientific settings for which the binomial data are often overdispersed. The standard generalized linear mixed effects model may result in severe underestimation of standard errors of estimated regression parameters in such cases and hence potentially bias the statistical inference. In this paper, we propose a longitudinal beta-binomial model for overdispersed binomial data and estimate the regression parameters under a probit model using the generalized estimating equation method. A hybrid algorithm of the Fisher scoring and the method of moments is implemented for computing the method. Extensive simulation studies are conducted to justify the validity of the proposed method. Finally, the proposed method is applied to analyze functional impairment in subjects who are at risk of Huntington disease from a multisite observational study of prodromal Huntington disease. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Expansion around half-integer values, binomial sums, and inverse binomial sums

    International Nuclear Information System (INIS)

    Weinzierl, Stefan

    2004-01-01

    I consider the expansion of transcendental functions in a small parameter around rational numbers. This includes in particular the expansion around half-integer values. I present algorithms which are suitable for an implementation within a symbolic computer algebra system. The method is an extension of the technique of nested sums. The algorithms allow in addition the evaluation of binomial sums, inverse binomial sums and generalizations thereof

  10. Tomography of binomial states of the radiation field

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    2004-01-01

    The symplectic, optical, and photon-number tomographic symbols of binomial states of the radiation field are studied. Explicit relations for all tomograms of the binomial states are obtained. Two measures for nonclassical properties of these states are discussed.

  11. Estimation of the house money effect using hurdle models

    OpenAIRE

    Engel, Christoph; Moffat, Peter G.

    2012-01-01

    Evidence from an experiment investigating the “house money effect” in the context of a public goods game is reconsidered. Analysis is performed within the framework of the panel hurdle model, in which subjects are assumed to be one of two types: free-riders, and potential contributors. The effect of house money is seen to be significant in the first hurdle: specifically, house money makes a subject more likely to be a potential contributor. Hence we find that the effect of house money is more...

  12. Preservation of South African steamed bread using hurdle technology

    CSIR Research Space (South Africa)

    Lombard, GE

    2000-01-01

    Full Text Available To transform traditional South African steamed bread, a dumpling-like product, into a convenient ready-to-eat form in a can, the application of various hurdles was investigated. Prevention of the growth of Clostridium botulinum in this low acid...

  13. Pooling overdispersed binomial data to estimate event rate.

    Science.gov (United States)

    Young-Xu, Yinong; Chan, K Arnold

    2008-08-19

    The beta-binomial model is one of the methods that can be used to validly combine event rates from overdispersed binomial data. Our objective is to provide a full description of this method and to update and broaden its applications in clinical and public health research. We describe the statistical theories behind the beta-binomial model and the associated estimation methods. We supply information about statistical software that can provide beta-binomial estimations. Using a published example, we illustrate the application of the beta-binomial model when pooling overdispersed binomial data. In an example regarding the safety of oral antifungal treatments, we had 41 treatment arms with event rates varying from 0% to 13.89%. Using the beta-binomial model, we obtained a summary event rate of 3.44% with a standard error of 0.59%. The parameters of the beta-binomial model took the values of 1.24 for alpha and 34.73 for beta. The beta-binomial model can provide a robust estimate for the summary event rate by pooling overdispersed binomial data from different studies. The explanation of the method and the demonstration of its applications should help researchers incorporate the beta-binomial method as they aggregate probabilities of events from heterogeneous studies.

  14. Pooling overdispersed binomial data to estimate event rate

    Directory of Open Access Journals (Sweden)

    Chan K Arnold

    2008-08-01

    Full Text Available Abstract Background The beta-binomial model is one of the methods that can be used to validly combine event rates from overdispersed binomial data. Our objective is to provide a full description of this method and to update and broaden its applications in clinical and public health research. Methods We describe the statistical theories behind the beta-binomial model and the associated estimation methods. We supply information about statistical software that can provide beta-binomial estimations. Using a published example, we illustrate the application of the beta-binomial model when pooling overdispersed binomial data. Results In an example regarding the safety of oral antifungal treatments, we had 41 treatment arms with event rates varying from 0% to 13.89%. Using the beta-binomial model, we obtained a summary event rate of 3.44% with a standard error of 0.59%. The parameters of the beta-binomial model took the values of 1.24 for alpha and 34.73 for beta. Conclusion The beta-binomial model can provide a robust estimate for the summary event rate by pooling overdispersed binomial data from different studies. The explanation of the method and the demonstration of its applications should help researchers incorporate the beta-binomial method as they aggregate probabilities of events from heterogeneous studies.

  15. On Using Selection Procedures with Binomial Models.

    Science.gov (United States)

    1983-10-01

    eds.), Shinko Tsusho Co. Ltd., Tokyo, Japan , pp. 501-533. Gupta, S. S. and Sobel, M. (1960). Selecting a subset containing the best of several...IA_____3_6r__I____ *TITLE food A$ieweI L TYPE of 09PORT 6 PERIOD COVERED ON USING SELECTION PROCEDURES WITH BINOMIAL MODELS Technical 6. PeSPRFeauS1 ONG. REPORT...ontoedis stoc toeSI. to Ei.,..,t&* toemR.,. 14. SUPPOLEMENTARY MOCTES 19. Rey WORDS (Coatiou. 40 ow.oa* edo if Necesary and #do""&a by block number

  16. Bayesian analysis of a correlated binomial model

    OpenAIRE

    Diniz, Carlos A. R.; Tutia, Marcelo H.; Leite, Jose G.

    2010-01-01

    In this paper a Bayesian approach is applied to the correlated binomial model, CB(n, p, ρ), proposed by Luceño (Comput. Statist. Data Anal. 20 (1995) 511–520). The data augmentation scheme is used in order to overcome the complexity of the mixture likelihood. MCMC methods, including Gibbs sampling and Metropolis within Gibbs, are applied to estimate the posterior marginal for the probability of success p and for the correlation coefficient ρ. The sensitivity of the posterior is studied taking...

  17. Extending the Binomial Checkpointing Technique for Resilience

    Energy Technology Data Exchange (ETDEWEB)

    Walther, Andrea; Narayanan, Sri Hari Krishna

    2016-10-10

    In terms of computing time, adjoint methods offer a very attractive alternative to compute gradient information, re- quired, e.g., for optimization purposes. However, together with this very favorable temporal complexity result comes a memory requirement that is in essence proportional with the operation count of the underlying function, e.g., if algo- rithmic differentiation is used to provide the adjoints. For this reason, checkpointing approaches in many variants have become popular. This paper analyzes an extension of the so-called binomial approach to cover also possible failures of the computing systems. Such a measure of precaution is of special interest for massive parallel simulations and adjoint calculations where the mean time between failure of the large scale computing system is smaller than the time needed to complete the calculation of the adjoint information. We de- scribe the extensions of standard checkpointing approaches required for such resilience, provide a corresponding imple- mentation and discuss numerical results.

  18. Forward selection two sample binomial test

    Science.gov (United States)

    Wong, Kam-Fai; Wong, Weng-Kee; Lin, Miao-Shan

    2016-01-01

    Fisher’s exact test (FET) is a conditional method that is frequently used to analyze data in a 2 × 2 table for small samples. This test is conservative and attempts have been made to modify the test to make it less conservative. For example, Crans and Shuster (2008) proposed adding more points in the rejection region to make the test more powerful. We provide another way to modify the test to make it less conservative by using two independent binomial distributions as the reference distribution for the test statistic. We compare our new test with several methods and show that our test has advantages over existing methods in terms of control of the type 1 and type 2 errors. We reanalyze results from an oncology trial using our proposed method and our software which is freely available to the reader. PMID:27335577

  19. Fractional Sums and Differences with Binomial Coefficients

    Directory of Open Access Journals (Sweden)

    Thabet Abdeljawad

    2013-01-01

    Full Text Available In fractional calculus, there are two approaches to obtain fractional derivatives. The first approach is by iterating the integral and then defining a fractional order by using Cauchy formula to obtain Riemann fractional integrals and derivatives. The second approach is by iterating the derivative and then defining a fractional order by making use of the binomial theorem to obtain Grünwald-Letnikov fractional derivatives. In this paper we formulate the delta and nabla discrete versions for left and right fractional integrals and derivatives representing the second approach. Then, we use the discrete version of the Q-operator and some discrete fractional dual identities to prove that the presented fractional differences and sums coincide with the discrete Riemann ones describing the first approach.

  20. Hurdles to health: immigrant and refugee health care in Australia.

    Science.gov (United States)

    Murray, Sally B; Skull, Sue A

    2005-02-01

    Refugees and asylum seekers face a number of barriers to accessing health care and improved health status. These include language difficulties, financial need and unemployment, cultural differences, legal barriers and a health workforce with generally low awareness of issues specific to refugees. Importantly, current Australian government migration and settlement policy also impacts on access to health and health status. An adequate understanding of these 'hurdles to health' is a prerequisite for health providers and health service managers if they are to tailor health care and services appropriately. We include tables of available resources and entitlements to health care according to visa category to assist providers and managers.

  1. Discovering Binomial Identities with PascGaloisJE

    Science.gov (United States)

    Evans, Tyler J.

    2008-01-01

    We describe exercises in which students use PascGaloisJE to formulate conjectures about certain binomial identities which hold when the binomial coefficients are interpreted as elements in the cyclic group Z[subscript p] of integers modulo a prime integer "p". In addition to having an appealing visual component, these exercises are open-ended and…

  2. Penggunaan Model Binomial Pada Penentuan Harga Opsi Saham Karyawan

    Directory of Open Access Journals (Sweden)

    Dara Puspita Anggraeni

    2015-11-01

    Full Text Available Binomial Model for Valuing Employee Stock Options. Employee Stock Options (ESO differ from standard exchange-traded options. The three main differences in a valuation model for employee stock options : Vesting Period, Exit Rate and Non-Transferability. In this thesis, the model for valuing employee stock options discussed. This model are implement with a generalized binomial model.

  3. A Mechanistic Beta-Binomial Probability Model for mRNA Sequencing Data.

    Science.gov (United States)

    Smith, Gregory R; Birtwistle, Marc R

    2016-01-01

    A main application for mRNA sequencing (mRNAseq) is determining lists of differentially-expressed genes (DEGs) between two or more conditions. Several software packages exist to produce DEGs from mRNAseq data, but they typically yield different DEGs, sometimes markedly so. The underlying probability model used to describe mRNAseq data is central to deriving DEGs, and not surprisingly most softwares use different models and assumptions to analyze mRNAseq data. Here, we propose a mechanistic justification to model mRNAseq as a binomial process, with data from technical replicates given by a binomial distribution, and data from biological replicates well-described by a beta-binomial distribution. We demonstrate good agreement of this model with two large datasets. We show that an emergent feature of the beta-binomial distribution, given parameter regimes typical for mRNAseq experiments, is the well-known quadratic polynomial scaling of variance with the mean. The so-called dispersion parameter controls this scaling, and our analysis suggests that the dispersion parameter is a continually decreasing function of the mean, as opposed to current approaches that impose an asymptotic value to the dispersion parameter at moderate mean read counts. We show how this leads to current approaches overestimating variance for moderately to highly expressed genes, which inflates false negative rates. Describing mRNAseq data with a beta-binomial distribution thus may be preferred since its parameters are relatable to the mechanistic underpinnings of the technique and may improve the consistency of DEG analysis across softwares, particularly for moderately to highly expressed genes.

  4. Growing Pains: New Zealand Qualitative Evidence on Hurdles to Exporting Growth

    OpenAIRE

    Geoff Simmons

    2002-01-01

    This paper surveys qualitative evidence with the aim of identifying consistent issues surrounding the growth of New Zealand firms. The available literature is focussed on exporters and raises the possibility of two “hurdles” to growth for New Zealand firms. The first is the fixed-cost hurdle to entering exporting. The second is the hurdle of establishing the offshore distribution channels required for continued growth. While the evidence for these hurdles is far from conclusive, their existen...

  5. Hurdles that impede economic evaluations of welfare interventions.

    Science.gov (United States)

    Schepers, Janne; Annemans, Lieven; Simoens, Steven

    2015-01-01

    Compared with economic evaluations of healthcare interventions, less experience has been gained in the field of economic evaluation of welfare interventions. This review suggests possible approaches to address four previously identified hurdles in economic evaluations of welfare interventions. After literature was searched through MEDLINE and EMBASE, it was found that Health-Related-Quality-of-Life questionnaires related to the condition of the target population are needed, instead of generic instruments. These condition-specific instruments use a multidimensional approach. There are specific instruments needed to take account of influences on informal caregivers. Moreover, it was shown that several aspects, such as crime rates and employment should be considered to estimate the impact on societal costs. Finally, the intervention must be described in detail and well defined to reduce variability. In conclusion, economic evaluations of welfare interventions increase complexity. These must be accounted for to permit valid assessments of the value for money of welfare interventions.

  6. Extension of Space Food Shelf Life Through Hurdle Approach

    Science.gov (United States)

    Cooper, M. R.; Sirmons, T. A.; Froio-Blumsack, D.; Mohr, L.; Young, M.; Douglas, G. L.

    2018-01-01

    The processed and prepackaged space food system is the main source of crew nutrition, and hence central to astronaut health and performance. Unfortunately, space food quality and nutrition degrade to unacceptable levels in two to three years with current food stabilization technologies. Future exploration missions will require a food system that remains safe, acceptable and nutritious through five years of storage within vehicle resource constraints. The potential of stabilization technologies (alternative storage temperatures, processing, formulation, ingredient source, packaging, and preparation procedures), when combined in hurdle approach, to mitigate quality and nutritional degradation is being assessed. Sixteen representative foods from the International Space Station food system were chosen for production and analysis and will be evaluated initially and at one, three, and five years with potential for analysis at seven years if necessary. Analysis includes changes in color, texture, nutrition, sensory quality, and rehydration ratio when applicable. The food samples will be stored at -20 C, 4 C, and 21 C. Select food samples will also be evaluated at -80 C to determine the impacts of ultra-cold storage after one and five years. Packaging film barrier properties and mechanical integrity will be assessed before and after processing and storage. At the study conclusion, if tested hurdles are adequate, formulation, processing, and storage combinations will be uniquely identified for processed food matrices to achieve a five-year shelf life. This study will provide one of the most comprehensive investigations of long duration food stability ever completed, and the achievement of extended food system stability will have profound impacts to health and performance for spaceflight crews and for relief efforts and military applications on Earth.

  7. Application of binomial-edited CPMG to shale characterization.

    Science.gov (United States)

    Washburn, Kathryn E; Birdwell, Justin E

    2014-09-01

    Unconventional shale resources may contain a significant amount of hydrogen in organic solids such as kerogen, but it is not possible to directly detect these solids with many NMR systems. Binomial-edited pulse sequences capitalize on magnetization transfer between solids, semi-solids, and liquids to provide an indirect method of detecting solid organic materials in shales. When the organic solids can be directly measured, binomial-editing helps distinguish between different phases. We applied a binomial-edited CPMG pulse sequence to a range of natural and experimentally-altered shale samples. The most substantial signal loss is seen in shales rich in organic solids while fluids associated with inorganic pores seem essentially unaffected. This suggests that binomial-editing is a potential method for determining fluid locations, solid organic content, and kerogen-bitumen discrimination. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Entanglement of Generalized Two-Mode Binomial States and Teleportation

    International Nuclear Information System (INIS)

    Wang Dongmei; Yu Youhong

    2009-01-01

    The entanglement of the generalized two-mode binomial states in the phase damping channel is studied by making use of the relative entropy of the entanglement. It is shown that the factors of q and p play the crucial roles in control the relative entropy of the entanglement. Furthermore, we propose a scheme of teleporting an unknown state via the generalized two-mode binomial states, and calculate the mean fidelity of the scheme. (general)

  9. Detecting non-binomial sex allocation when developmental mortality operates.

    Science.gov (United States)

    Wilkinson, Richard D; Kapranas, Apostolos; Hardy, Ian C W

    2016-11-07

    Optimal sex allocation theory is one of the most intricately developed areas of evolutionary ecology. Under a range of conditions, particularly under population sub-division, selection favours sex being allocated to offspring non-randomly, generating non-binomial variances of offspring group sex ratios. Detecting non-binomial sex allocation is complicated by stochastic developmental mortality, as offspring sex can often only be identified on maturity with the sex of non-maturing offspring remaining unknown. We show that current approaches for detecting non-binomiality have limited ability to detect non-binomial sex allocation when developmental mortality has occurred. We present a new procedure using an explicit model of sex allocation and mortality and develop a Bayesian model selection approach (available as an R package). We use the double and multiplicative binomial distributions to model over- and under-dispersed sex allocation and show how to calculate Bayes factors for comparing these alternative models to the null hypothesis of binomial sex allocation. The ability to detect non-binomial sex allocation is greatly increased, particularly in cases where mortality is common. The use of Bayesian methods allows for the quantification of the evidence in favour of each hypothesis, and our modelling approach provides an improved descriptive capability over existing approaches. We use a simulation study to demonstrate substantial improvements in power for detecting non-binomial sex allocation in situations where current methods fail, and we illustrate the approach in real scenarios using empirically obtained datasets on the sexual composition of groups of gregarious parasitoid wasps. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. On some binomial [Formula: see text]-difference sequence spaces.

    Science.gov (United States)

    Meng, Jian; Song, Meimei

    2017-01-01

    In this paper, we introduce the binomial sequence spaces [Formula: see text], [Formula: see text] and [Formula: see text] by combining the binomial transformation and difference operator. We prove the BK -property and some inclusion relations. Furthermore, we obtain Schauder bases and compute the α -, β - and γ -duals of these sequence spaces. Finally, we characterize matrix transformations on the sequence space [Formula: see text].

  11. Hurdling barriers through market uncertainty: Case studies ininnovative technology adoption

    Energy Technology Data Exchange (ETDEWEB)

    Payne, Christopher T.; Radspieler Jr., Anthony; Payne, Jack

    2002-08-18

    The crisis atmosphere surrounding electricity availability in California during the summer of 2001 produced two distinct phenomena in commercial energy consumption decision-making: desires to guarantee energy availability while blackouts were still widely anticipated, and desires to avoid or mitigate significant price increases when higher commercial electricity tariffs took effect. The climate of increased consideration of these factors seems to have led, in some cases, to greater willingness on the part of business decision-makers to consider highly innovative technologies. This paper examines three case studies of innovative technology adoption: retrofit of time-and-temperature signs on an office building; installation of fuel cells to supply power, heating, and cooling to the same building; and installation of a gas-fired heat pump at a microbrewery. We examine the decision process that led to adoption of these technologies. In each case, specific constraints had made more conventional energy-efficient technologies inapplicable. We examine how these barriers to technology adoption developed over time, how the California energy decision-making climate combined with the characteristics of these innovative technologies to overcome the barriers, and what the implications of hurdling these barriers are for future energy decisions within the firms.

  12. [Using log-binomial model for estimating the prevalence ratio].

    Science.gov (United States)

    Ye, Rong; Gao, Yan-hui; Yang, Yi; Chen, Yue

    2010-05-01

    To estimate the prevalence ratios, using a log-binomial model with or without continuous covariates. Prevalence ratios for individuals' attitude towards smoking-ban legislation associated with smoking status, estimated by using a log-binomial model were compared with odds ratios estimated by logistic regression model. In the log-binomial modeling, maximum likelihood method was used when there were no continuous covariates and COPY approach was used if the model did not converge, for example due to the existence of continuous covariates. We examined the association between individuals' attitude towards smoking-ban legislation and smoking status in men and women. Prevalence ratio and odds ratio estimation provided similar results for the association in women since smoking was not common. In men however, the odds ratio estimates were markedly larger than the prevalence ratios due to a higher prevalence of outcome. The log-binomial model did not converge when age was included as a continuous covariate and COPY method was used to deal with the situation. All analysis was performed by SAS. Prevalence ratio seemed to better measure the association than odds ratio when prevalence is high. SAS programs were provided to calculate the prevalence ratios with or without continuous covariates in the log-binomial regression analysis.

  13. Low Temperature and Modified Atmosphere: Hurdles for Antibiotic Resistance Transfer?

    Science.gov (United States)

    Van Meervenne, Eva; Van Coillie, Els; Van Weyenberg, Stephanie; Boon, Nico; Herman, Lieve; Devlieghere, Frank

    2015-12-01

    Food is an important dissemination route for antibiotic-resistant bacteria. Factors used during food production and preservation may contribute to the transfer of antibiotic resistance genes, but research on this subject is scarce. In this study, the effect of temperature (7 to 37°C) and modified atmosphere packaging (air, 50% CO2-50% N2, and 100% N2) on antibiotic resistance transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes was evaluated. Filter mating was performed on nonselective agar plates with high-density inocula. A more realistic setup was created by performing modified atmosphere experiments on cooked ham using high-density and low-density inocula. Plasmid transfer was observed between 10 and 37°C, with plasmid transfer also observed at 7°C during a prolonged incubation period. When high-density inocula were used, transconjugants were detected, both on agar plates and cooked ham, under the three atmospheres (air, 50% CO2-50% N2, and 100% N2) at 7°C. This yielded a median transfer ratio (number of transconjugants/number of recipients) with an order of magnitude of 10(-4) to 10(-6). With low-density inocula, transfer was only detected under the 100% N2 atmosphere after 10-day incubation at 7°C, yielding a transfer ratio of 10(-5). Under this condition, the highest bacterial density was obtained. The results indicate that low temperature and modified atmosphere packaging, two important hurdles in the food industry, do not necessarily prevent plasmid transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes.

  14. Chromosome aberration analysis based on a beta-binomial distribution

    International Nuclear Information System (INIS)

    Otake, Masanori; Prentice, R.L.

    1983-10-01

    Analyses carried out here generalized on earlier studies of chromosomal aberrations in the populations of Hiroshima and Nagasaki, by allowing extra-binomial variation in aberrant cell counts corresponding to within-subject correlations in cell aberrations. Strong within-subject correlations were detected with corresponding standard errors for the average number of aberrant cells that were often substantially larger than was previously assumed. The extra-binomial variation is accomodated in the analysis in the present report, as described in the section on dose-response models, by using a beta-binomial (B-B) variance structure. It is emphasized that we have generally satisfactory agreement between the observed and the B-B fitted frequencies by city-dose category. The chromosomal aberration data considered here are not extensive enough to allow a precise discrimination between competing dose-response models. A quadratic gamma ray and linear neutron model, however, most closely fits the chromosome data. (author)

  15. The k-Binomial Transforms and the Hankel Transform

    Science.gov (United States)

    Spivey, Michael Z.; Steil, Laura L.

    2006-01-01

    We give a new proof of the invariance of the Hankel transform under the binomial transform of a sequence. Our method of proof leads to three variations of the binomial transform; we call these the k-binomial transforms. We give a simple means of constructing these transforms via a triangle of numbers. We show how the exponential generating function of a sequence changes after our transforms are applied, and we use this to prove that several sequences in the On-Line Encyclopedia of Integer Sequences are related via our transforms. In the process, we prove three conjectures in the OEIS. Addressing a question of Layman, we then show that the Hankel transform of a sequence is invariant under one of our transforms, and we show how the Hankel transform changes after the other two transforms are applied. Finally, we use these results to determine the Hankel transforms of several integer sequences.

  16. Estimation of Log-Linear-Binomial Distribution with Applications

    Directory of Open Access Journals (Sweden)

    Elsayed Ali Habib

    2010-01-01

    Full Text Available Log-linear-binomial distribution was introduced for describing the behavior of the sum of dependent Bernoulli random variables. The distribution is a generalization of binomial distribution that allows construction of a broad class of distributions. In this paper, we consider the problem of estimating the two parameters of log-linearbinomial distribution by moment and maximum likelihood methods. The distribution is used to fit genetic data and to obtain the sampling distribution of the sign test under dependence among trials.

  17. Generation of the reciprocal-binomial state for optical fields

    International Nuclear Information System (INIS)

    Valverde, C.; Avelar, A.T.; Baseia, B.; Malbouisson, J.M.C.

    2003-01-01

    We compare the efficiencies of two interesting schemes to generate truncated states of the light field in running modes, namely the 'quantum scissors' and the 'beam-splitter array' schemes. The latter is applied to create the reciprocal-binomial state as a travelling wave, required to implement recent experimental proposals of phase-distribution determination and of quantum lithography

  18. Calculation of generalized secant integral using binomial coefficients

    International Nuclear Information System (INIS)

    Guseinov, I.I.; Mamedov, B.A.

    2004-01-01

    A single series expansion relation is derived for the generalized secant (GS) integral in terms of binomial coefficients, exponential integrals and incomplete gamma functions. The convergence of the series is tested by the concrete cases of parameters. The formulas given in this study for the evaluation of GS integral show good rate of convergence and numerical stability

  19. Selecting Tools to Model Integer and Binomial Multiplication

    Science.gov (United States)

    Pratt, Sarah Smitherman; Eddy, Colleen M.

    2017-01-01

    Mathematics teachers frequently provide concrete manipulatives to students during instruction; however, the rationale for using certain manipulatives in conjunction with concepts may not be explored. This article focuses on area models that are currently used in classrooms to provide concrete examples of integer and binomial multiplication. The…

  20. Using the β-binomial distribution to characterize forest health

    Science.gov (United States)

    S.J. Zarnoch; R.L. Anderson; R.M. Sheffield

    1995-01-01

    The β-binomial distribution is suggested as a model for describing and analyzing the dichotomous data obtained from programs monitoring the health of forests in the United States. Maximum likelihood estimation of the parameters is given as well as asymptotic likelihood ratio tests. The procedure is illustrated with data on dogwood anthracnose infection (caused...

  1. Currency lookback options and observation frequency: A binomial approach

    NARCIS (Netherlands)

    T.H.F. Cheuk; A.C.F. Vorst (Ton)

    1997-01-01

    textabstractIn the last decade, interest in exotic options has been growing, especially in the over-the-counter currency market. In this paper we consider Iookback currency options, which are path-dependent. We show that a one-state variable binomial model for currency Iookback options can

  2. Stochastic analysis of complex reaction networks using binomial moment equations.

    Science.gov (United States)

    Barzel, Baruch; Biham, Ofer

    2012-09-01

    The stochastic analysis of complex reaction networks is a difficult problem because the number of microscopic states in such systems increases exponentially with the number of reactive species. Direct integration of the master equation is thus infeasible and is most often replaced by Monte Carlo simulations. While Monte Carlo simulations are a highly effective tool, equation-based formulations are more amenable to analytical treatment and may provide deeper insight into the dynamics of the network. Here, we present a highly efficient equation-based method for the analysis of stochastic reaction networks. The method is based on the recently introduced binomial moment equations [Barzel and Biham, Phys. Rev. Lett. 106, 150602 (2011)]. The binomial moments are linear combinations of the ordinary moments of the probability distribution function of the population sizes of the interacting species. They capture the essential combinatorics of the reaction processes reflecting their stoichiometric structure. This leads to a simple and transparent form of the equations, and allows a highly efficient and surprisingly simple truncation scheme. Unlike ordinary moment equations, in which the inclusion of high order moments is prohibitively complicated, the binomial moment equations can be easily constructed up to any desired order. The result is a set of equations that enables the stochastic analysis of complex reaction networks under a broad range of conditions. The number of equations is dramatically reduced from the exponential proliferation of the master equation to a polynomial (and often quadratic) dependence on the number of reactive species in the binomial moment equations. The aim of this paper is twofold: to present a complete derivation of the binomial moment equations; to demonstrate the applicability of the moment equations for a representative set of example networks, in which stochastic effects play an important role.

  3. Generalization of Binomial Coefficients to Numbers on the Nodes of Graphs

    NARCIS (Netherlands)

    Khmelnitskaya, A.; van der Laan, G.; Talman, Dolf

    2016-01-01

    The triangular array of binomial coefficients, or Pascal's triangle, is formed by starting with an apex of 1. Every row of Pascal's triangle can be seen as a line-graph, to each node of which the corresponding binomial coefficient is assigned. We show that the binomial coefficient of a node is equal

  4. Generalization of binomial coefficients to numbers on the nodes of graphs

    NARCIS (Netherlands)

    Khmelnitskaya, Anna Borisovna; van der Laan, Gerard; Talman, Dolf

    The triangular array of binomial coefficients, or Pascal's triangle, is formed by starting with an apex of 1. Every row of Pascal's triangle can be seen as a line-graph, to each node of which the corresponding binomial coefficient is assigned. We show that the binomial coefficient of a node is equal

  5. Determination of finite-difference weights using scaled binomial windows

    KAUST Repository

    Chu, Chunlei

    2012-05-01

    The finite-difference method evaluates a derivative through a weighted summation of function values from neighboring grid nodes. Conventional finite-difference weights can be calculated either from Taylor series expansions or by Lagrange interpolation polynomials. The finite-difference method can be interpreted as a truncated convolutional counterpart of the pseudospectral method in the space domain. For this reason, we also can derive finite-difference operators by truncating the convolution series of the pseudospectral method. Various truncation windows can be employed for this purpose and they result in finite-difference operators with different dispersion properties. We found that there exists two families of scaled binomial windows that can be used to derive conventional finite-difference operators analytically. With a minor change, these scaled binomial windows can also be used to derive optimized finite-difference operators with enhanced dispersion properties. © 2012 Society of Exploration Geophysicists.

  6. Exact Group Sequential Methods for Estimating a Binomial Proportion

    Directory of Open Access Journals (Sweden)

    Zhengjia Chen

    2013-01-01

    Full Text Available We first review existing sequential methods for estimating a binomial proportion. Afterward, we propose a new family of group sequential sampling schemes for estimating a binomial proportion with prescribed margin of error and confidence level. In particular, we establish the uniform controllability of coverage probability and the asymptotic optimality for such a family of sampling schemes. Our theoretical results establish the possibility that the parameters of this family of sampling schemes can be determined so that the prescribed level of confidence is guaranteed with little waste of samples. Analytic bounds for the cumulative distribution functions and expectations of sample numbers are derived. Moreover, we discuss the inherent connection of various sampling schemes. Numerical issues are addressed for improving the accuracy and efficiency of computation. Computational experiments are conducted for comparing sampling schemes. Illustrative examples are given for applications in clinical trials.

  7. Fat suppression in MR imaging with binomial pulse sequences

    International Nuclear Information System (INIS)

    Baudovin, C.J.; Bryant, D.J.; Bydder, G.M.; Young, I.R.

    1989-01-01

    This paper reports on a study to develop pulse sequences allowing suppression of fat signal on MR images without eliminating signal from other tissues with short T1. They have developed such a technique involving selective excitation of protons in water, based on a binomial pulse sequence. Imaging is performed at 0.15 T. Careful shimming is performed to maximize separation of fat and water peaks. A spin-echo 1,500/80 sequence is used, employing 90 degrees pulse with transit frequency optimized for water with null excitation of 20 H offset, followed by a section-selective 180 degrees pulse. With use of the binomial sequence for imagining, reduction in fat signal is seen on images of the pelvis and legs of volunteers. Patient studies show dramatic improvement in visualization of prostatic carcinoma compared with standard sequences

  8. On pricing futures options on random binomial tree

    International Nuclear Information System (INIS)

    Bayram, Kamola; Ganikhodjaev, Nasir

    2013-01-01

    The discrete-time approach to real option valuation has typically been implemented in the finance literature using a binomial tree framework. Instead we develop a new model by randomizing the environment and call such model a random binomial tree. Whereas the usual model has only one environment (u, d) where the price of underlying asset can move by u times up and d times down, and pair (u, d) is constant over the life of the underlying asset, in our new model the underlying security is moving in two environments namely (u 1 , d 1 ) and (u 2 , d 2 ). Thus we obtain two volatilities σ 1 and σ 2 . This new approach enables calculations reflecting the real market since it consider the two states of market normal and extra ordinal. In this paper we define and study Futures options for such models.

  9. Data analysis using the Binomial Failure Rate common cause model

    International Nuclear Information System (INIS)

    Atwood, C.L.

    1983-09-01

    This report explains how to use the Binomial Failure Rate (BFR) method to estimate common cause failure rates. The entire method is described, beginning with the conceptual model, and covering practical issues of data preparation, treatment of variation in the failure rates, Bayesian estimation of the quantities of interest, checking the model assumptions for lack of fit to the data, and the ultimate application of the answers

  10. Hits per trial: Basic analysis of binomial data

    International Nuclear Information System (INIS)

    Atwood, C.L.

    1994-09-01

    This report presents simple statistical methods for analyzing binomial data, such as the number of failures in some number of demands. It gives point estimates, confidence intervals, and Bayesian intervals for the failure probability. It shows how to compare subsets of the data, both graphically and by statistical tests, and how to look for trends in time. It presents a compound model when the failure probability varies randomly. Examples and SAS programs are given

  11. Hits per trial: Basic analysis of binomial data

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, C.L.

    1994-09-01

    This report presents simple statistical methods for analyzing binomial data, such as the number of failures in some number of demands. It gives point estimates, confidence intervals, and Bayesian intervals for the failure probability. It shows how to compare subsets of the data, both graphically and by statistical tests, and how to look for trends in time. It presents a compound model when the failure probability varies randomly. Examples and SAS programs are given.

  12. Correlation Structures of Correlated Binomial Models and Implied Default Distribution

    OpenAIRE

    S. Mori; K. Kitsukawa; M. Hisakado

    2006-01-01

    We show how to analyze and interpret the correlation structures, the conditional expectation values and correlation coefficients of exchangeable Bernoulli random variables. We study implied default distributions for the iTraxx-CJ tranches and some popular probabilistic models, including the Gaussian copula model, Beta binomial distribution model and long-range Ising model. We interpret the differences in their profiles in terms of the correlation structures. The implied default distribution h...

  13. Standardized binomial models for risk or prevalence ratios and differences.

    Science.gov (United States)

    Richardson, David B; Kinlaw, Alan C; MacLehose, Richard F; Cole, Stephen R

    2015-10-01

    Epidemiologists often analyse binary outcomes in cohort and cross-sectional studies using multivariable logistic regression models, yielding estimates of adjusted odds ratios. It is widely known that the odds ratio closely approximates the risk or prevalence ratio when the outcome is rare, and it does not do so when the outcome is common. Consequently, investigators may decide to directly estimate the risk or prevalence ratio using a log binomial regression model. We describe the use of a marginal structural binomial regression model to estimate standardized risk or prevalence ratios and differences. We illustrate the proposed approach using data from a cohort study of coronary heart disease status in Evans County, Georgia, USA. The approach reduces problems with model convergence typical of log binomial regression by shifting all explanatory variables except the exposures of primary interest from the linear predictor of the outcome regression model to a model for the standardization weights. The approach also facilitates evaluation of departures from additivity in the joint effects of two exposures. Epidemiologists should consider reporting standardized risk or prevalence ratios and differences in cohort and cross-sectional studies. These are readily-obtained using the SAS, Stata and R statistical software packages. The proposed approach estimates the exposure effect in the total population. © The Author 2015; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

  14. Abstract knowledge versus direct experience in processing of binomial expressions.

    Science.gov (United States)

    Morgan, Emily; Levy, Roger

    2016-12-01

    We ask whether word order preferences for binomial expressions of the form A and B (e.g. bread and butter) are driven by abstract linguistic knowledge of ordering constraints referencing the semantic, phonological, and lexical properties of the constituent words, or by prior direct experience with the specific items in questions. Using forced-choice and self-paced reading tasks, we demonstrate that online processing of never-before-seen binomials is influenced by abstract knowledge of ordering constraints, which we estimate with a probabilistic model. In contrast, online processing of highly frequent binomials is primarily driven by direct experience, which we estimate from corpus frequency counts. We propose a trade-off wherein processing of novel expressions relies upon abstract knowledge, while reliance upon direct experience increases with increased exposure to an expression. Our findings support theories of language processing in which both compositional generation and direct, holistic reuse of multi-word expressions play crucial roles. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Does the admission procedure lack the fourth hurdle (socio-economic criteria)?

    Science.gov (United States)

    Hapke, H J

    1991-01-01

    Besides the 3 aspects of drug safety, ie stability, efficacy and harmlessness, a fourth hurdle for veterinary drug licensing is discussed: socio-economic criteria. These criteria have not yet been established and the scientific aspects are difficult to define. After discussion of the advantages and disadvantages of the fourth hurdle, the conclusion is that there is no need to introduce a fourth criterion into the admission procedure for veterinary drugs, feed additives or any other chemicals which increase animal health or promote their growth.

  16. Hurdles overcome in technology transfer for AIET and Positive outcome in Indian patients

    Directory of Open Access Journals (Sweden)

    Dedeepiya V

    2012-01-01

    Full Text Available Introduction Cell based immunotherapies have been in practice in Japan for the past two decades with established clinical trials on its efficacy in both solid tumours and hematological malignancies including gastric cancer, ovarian cancer , lung cancer and liver cancer. [1,2,3,4] In India, NCRM has been providing Autologous Immune Enhancement Therapy (AIET using autologous Natural Killer (NK cells and activated T Lymphocytes for Cancer since 2005 following the established protocols practiced by the Biotherapy Institute of Japan. Significant outcome achieved after AIET in advanced pancreatic cancer, Acute Myeloid leukemia (AML in Indian patients have already been reported. [5, 6] Here we report our experience in few more patients and present the hurdles overcome and lessons learned in translating the technology from Japan to India Case Details: Case 1: A 54 year-old female presented with Stage IV recurrent ovarian malignancy in 2010 with a history of previous surgery and chemotherapy for ovarian malignancy in June 2009. The CA-125 level of 243 U/ml. CT scan revealed lesions in the liver, spleen, along the greater curvature of body of stomach and in the perisplenic region, between the medial aspect of liver and stomach and in the right inguinal region. She was suggested six cycles of chemotherapy with Doxorubicin (50 mg and Carboplatin (450 mg along with AIET. After proper informed consent, the peripheral blood was withdrawn and the in vitro expansion of the NK cells, activated T Lymphocytes from the peripheral blood was performed using the protocol reported earlier. [7] Average cell count after the in vitro expansion was 1.2 X 108 cells. Six transfusions of the in vitro expanded NK cells and activated T lymphocytes were administered following which the CA-125 decreased to 4.7 U/mL. CT scan taken in December 2010 showed a regression of the lesions in the spleen and perisplenic peritoneal deposits, stable hepatic lesions and resolution of

  17. A comparison of observation-level random effect and Beta-Binomial models for modelling overdispersion in Binomial data in ecology & evolution.

    Science.gov (United States)

    Harrison, Xavier A

    2015-01-01

    Overdispersion is a common feature of models of biological data, but researchers often fail to model the excess variation driving the overdispersion, resulting in biased parameter estimates and standard errors. Quantifying and modeling overdispersion when it is present is therefore critical for robust biological inference. One means to account for overdispersion is to add an observation-level random effect (OLRE) to a model, where each data point receives a unique level of a random effect that can absorb the extra-parametric variation in the data. Although some studies have investigated the utility of OLRE to model overdispersion in Poisson count data, studies doing so for Binomial proportion data are scarce. Here I use a simulation approach to investigate the ability of both OLRE models and Beta-Binomial models to recover unbiased parameter estimates in mixed effects models of Binomial data under various degrees of overdispersion. In addition, as ecologists often fit random intercept terms to models when the random effect sample size is low (Binomial mixture model, leading to biased slope and intercept estimates, but performed well for overdispersion generated by adding random noise to the linear predictor. Comparison of parameter estimates from an OLRE model with those from its corresponding Beta-Binomial model readily identified when OLRE were performing poorly due to disagreement between effect sizes, and this strategy should be employed whenever OLRE are used for Binomial data to assess their reliability. Beta-Binomial models performed well across all contexts, but showed a tendency to underestimate effect sizes when modelling non-Beta-Binomial data. Finally, both OLRE and Beta-Binomial models performed poorly when models contained Binomial data, but that they do not perform well in all circumstances and researchers should take care to verify the robustness of parameter estimates of OLRE models.

  18. A spatiotemporal geostatistical hurdle model approach for short-term deforestation prediction

    NARCIS (Netherlands)

    Ribeiro Sales, Marcio; Bruin, De Sytze; Herold, Martin; Kyriakidis, Phaedon; Souza, Carlos

    2017-01-01

    This paper introduces and tests a geostatistical spatiotemporal hurdle approach for predicting the spatial distribution of future deforestation (one to three years ahead in time). The method accounts for neighborhood effects by modeling the auto-correlation of occurrence and intensity of

  19. Jumping the PBL Implementation Hurdle: Supporting the Efforts of K-12 Teachers

    Science.gov (United States)

    Ertmer, Peggy A.; Simons, Krista D.

    2006-01-01

    While problem-based learning (PBL) has a relatively long history of successful use in medical and pre-professional schools, it has yet to be widely adopted by K--12 teachers. This may be due, in part, to the numerous challenges teachers experience when implementing PBL. In this paper, we describe specific hurdles that teachers are likely to…

  20. Kinetic and kinematic analysis of hurdle clearance of an African and ...

    African Journals Online (AJOL)

    . A world champion and a world record-holder, C.J, with a time of 12.91s, was chosen as a model-athlete in 110m hurdles in this study. He was compared with R.G, a Tunisian athlete and African champion based on his personal best of 13.90s.

  1. Hurdles in clinical implementation of academic advanced therapy medicinal products: A national evaluation.

    Science.gov (United States)

    de Wilde, Sofieke; Veltrop-Duits, Louise; Hoozemans-Strik, Merel; Ras, Thirza; Blom-Veenman, Janine; Guchelaar, Henk-Jan; Zandvliet, Maarten; Meij, Pauline

    2016-06-01

    Since the implementation of the European Union (EU) regulation for advanced therapy medicinal products (ATMPs) in 2009, only six ATMPs achieved marketing authorization approval in the EU. Recognizing the major developments in the ATMP field, starting mostly in academic institutions, we investigated which hurdles were experienced in the whole pathway of ATMP development towards clinical care. Quality interviews were executed with different stakeholders in The Netherlands involved in the ATMP development field, e.g. academic research groups, national authorities and patient organizations. Based on the hurdles mentioned in the interviews, questionnaires were subsequently sent to the academic principal investigators (PIs) and ATMP good manufacturing practice (GMP) facility managers to quantify these hurdles. Besides the familiar regulatory routes of marketing authorization (MA) and hospital exemption (HE), a part of the academic PIs perceived that ATMPs should become available by the Tissues and Cells Directive or did not anticipate on the next development steps towards implementation of their ATMP towards regular clinical care. The main hurdles identified were: inadequate financial support, rapidly evolving field, study-related problems, lacking regulatory knowledge, lack of collaborations and responsibility issues. Creating an academic environment stimulating and planning ATMP development and licensing as well as investing in expanding the relevant regulatory knowledge in academic institutions seems a prerequisite to develop ATMPs from bench to patient. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  2. Statistical properties of nonlinear intermediate states: binomial state

    Energy Technology Data Exchange (ETDEWEB)

    Abdalla, M Sebawe [Mathematics Department, College of Science, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia); Obada, A-S F [Department Mathematics, Faculty of Science, Al-Azhar University, Nasr City 11884, Cairo (Egypt); Darwish, M [Department of Physics, Faculty of Education, Suez Canal University, Al-Arish (Egypt)

    2005-12-01

    In the present paper we introduce a nonlinear binomial state (the state which interpolates between the nonlinear coherent and number states). The main investigation concentrates on the statistical properties for such a state where we consider the squeezing phenomenon by examining the variation in the quadrature variances for both normal and amplitude-squared squeezing. Examinations for the quasi-probability distribution functions (W-Wigner and Q-functions) are also given for both diagonal and off diagonal terms. The quadrature distribution and the phase distribution as well as the phase variances are discussed. Moreover, we give in detail a generation scheme for such state.

  3. Microbial comparative pan-genomics using binomial mixture models

    DEFF Research Database (Denmark)

    Ussery, David; Snipen, L; Almøy, T

    2009-01-01

    The size of the core- and pan-genome of bacterial species is a topic of increasing interest due to the growing number of sequenced prokaryote genomes, many from the same species. Attempts to estimate these quantities have been made, using regression methods or mixture models. We extend the latter...... occurring genes in the population. CONCLUSION: Analyzing pan-genomics data with binomial mixture models is a way to handle dependencies between genomes, which we find is always present. A bottleneck in the estimation procedure is the annotation of rarely occurring genes....

  4. Correlation Structures of Correlated Binomial Models and Implied Default Distribution

    Science.gov (United States)

    Mori, Shintaro; Kitsukawa, Kenji; Hisakado, Masato

    2008-11-01

    We show how to analyze and interpret the correlation structures, the conditional expectation values and correlation coefficients of exchangeable Bernoulli random variables. We study implied default distributions for the iTraxx-CJ tranches and some popular probabilistic models, including the Gaussian copula model, Beta binomial distribution model and long-range Ising model. We interpret the differences in their profiles in terms of the correlation structures. The implied default distribution has singular correlation structures, reflecting the credit market implications. We point out two possible origins of the singular behavior.

  5. The insights of health and welfare professionals on hurdles that impede economic evaluations of welfare interventions.

    Science.gov (United States)

    Schepers, J; Plaete, J; De Bourdeaudhuij, I; Annemans, L; Simoens, S

    2017-08-01

    Four hurdles associated with economic evaluations in welfare interventions were identified and discussed in a previous published literature review. These hurdles include (i) 'Ignoring the impact of condition-specific outcomes', (ii) 'Ignoring the impact of QoL externalities', (iii) 'Calculation of costs from a too narrow perspective' and (iv) 'The lack of well-described & standardized interventions'. This study aims to determine how healthcare providers and social workers experience and deal with these hurdles in practice and what solutions or new insights they would suggest. Twenty-two professionals of welfare interventions carried out in Flanders, were interviewed about the four described hurdles using a semi-structured interview. A thematic framework was developed to enable the qualitative analysis. The analysis of the semi-structured interviews was facilitated through the use of the software program QRS NVivo 10. The interviews revealed a clear need to tackle these hurdles. The interviewees confirmed that further study of condition-specific outcomes in economic evaluations are needed, especially in the field of mental health and stress. The proposed dimensions for the condition-specific questionnaires varied however between the groups of interviewees (i.e. general practitioners vs social workers). With respect to QoL externalities, the interviewees confirmed that welfare interventions have an impact on the social environment of the patient (friends and family). There was however no consensus on how this impact of QoL externalities should be taken into account in welfare interventions. Professionals also suggested that besides health care costs, the impact of welfare interventions on work productivity, the patients' social life and other items should be incorporated. Standardization appears to be of limited added value for most of the interviewees because they need a certain degree of freedom to interpret the intervention. Furthermore, the target population of

  6. Low reheating temperatures in monomial and binomial inflationary models

    International Nuclear Information System (INIS)

    Rehagen, Thomas; Gelmini, Graciela B.

    2015-01-01

    We investigate the allowed range of reheating temperature values in light of the Planck 2015 results and the recent joint analysis of Cosmic Microwave Background (CMB) data from the BICEP2/Keck Array and Planck experiments, using monomial and binomial inflationary potentials. While the well studied ϕ 2 inflationary potential is no longer favored by current CMB data, as well as ϕ p with p>2, a ϕ 1 potential and canonical reheating (w re =0) provide a good fit to the CMB measurements. In this last case, we find that the Planck 2015 68% confidence limit upper bound on the spectral index, n s , implies an upper bound on the reheating temperature of T re ≲6×10 10 GeV, and excludes instantaneous reheating. The low reheating temperatures allowed by this model open the possibility that dark matter could be produced during the reheating period instead of when the Universe is radiation dominated, which could lead to very different predictions for the relic density and momentum distribution of WIMPs, sterile neutrinos, and axions. We also study binomial inflationary potentials and show the effects of a small departure from a ϕ 1 potential. We find that as a subdominant ϕ 2 term in the potential increases, first instantaneous reheating becomes allowed, and then the lowest possible reheating temperature of T re =4 MeV is excluded by the Planck 2015 68% confidence limit

  7. Modelling alcohol consumption during adolescence using zero inflated negative binomial and decision trees

    Directory of Open Access Journals (Sweden)

    Alfonso Palmer

    2010-07-01

    Full Text Available Alcohol is currently the most consumed substance among the Spanish adolescent population. Some of the variables that bear an influence on this consumption include ease of access, use of alcohol by friends and some personality factors. The aim of this study was to analyze and quantify the predictive value of these variables specifically on alcohol consumption in the adolescent population. The useful sample was made up of 6,145 adolescents (49.8% boys and 50.2% girls with a mean age of 15.4 years (SE= 1.2. The data were analyzed using the statistical model for a count variable and Data Mining techniques. The results show the influence of ease of access, alcohol consumption by the group of friends, and certain personality factors on alcohol intake, allowing us to quantify the intensity of this influence according to age and gender. Knowing these factors is the starting point in elaborating specific preventive actions against alcohol consumption.

  8. Extended moment series and the parameters of the negative binomial distribution

    International Nuclear Information System (INIS)

    Bowman, K.O.

    1984-01-01

    Recent studies indicate that, for finite sample sizes, moment estimators may be superior to maximum likelihood estimators in some regions of parameter space. In this paper a statistic based on the central moment of the sample is expanded in a Taylor series using 24 derivatives and many more terms than previous expansions. A summary algorithm is required to find meaningful approximants using the higher-order coefficients. A example is presented and a comparison between theoretical assessment and simulation results is made

  9. Biomechanical study athletes’ movement techniques in the hurdles (on example of phase of flight

    Directory of Open Access Journals (Sweden)

    V.M. Adashevskiy

    2014-08-01

    Full Text Available Purpose: To design a theoretical biomechanical model of athletes’ movement techniques in the hurdles and then check there movements on real athletes. Material : In the practical part of the study participated 10 smortsmen. Results : Showing the possibility of constructing a theoretical model of hurdling technique. The basis of constructing a model using the known approaches in theoretical mechanics. Shows the calculated and actual performance movement of the athlete. Conclusions : The developed model provides a good theoretical understanding of the interactions of individual elements of movement and the ability to simulate different situations and to determine the optimal values of the kinematic and dynamic characteristics of the movement of the athlete. The model allows the individual elements of motion correction directly in the process of training. When analyzing art movement should consider specific features of physical development and anthropometric characteristics of the athlete's body.

  10. Covering Resilience: A Recent Development for Binomial Checkpointing

    Energy Technology Data Exchange (ETDEWEB)

    Walther, Andrea; Narayanan, Sri Hari Krishna

    2016-09-12

    In terms of computing time, adjoint methods offer a very attractive alternative to compute gradient information, required, e.g., for optimization purposes. However, together with this very favorable temporal complexity result comes a memory requirement that is in essence proportional with the operation count of the underlying function, e.g., if algorithmic differentiation is used to provide the adjoints. For this reason, checkpointing approaches in many variants have become popular. This paper analyzes an extension of the so-called binomial approach to cover also possible failures of the computing systems. Such a measure of precaution is of special interest for massive parallel simulations and adjoint calculations where the mean time between failure of the large scale computing system is smaller than the time needed to complete the calculation of the adjoint information. We describe the extensions of standard checkpointing approaches required for such resilience, provide a corresponding implementation and discuss first numerical results.

  11. A Bayesian equivalency test for two independent binomial proportions.

    Science.gov (United States)

    Kawasaki, Yohei; Shimokawa, Asanao; Yamada, Hiroshi; Miyaoka, Etsuo

    2016-01-01

    In clinical trials, it is often necessary to perform an equivalence study. The equivalence study requires actively denoting equivalence between two different drugs or treatments. Since it is not possible to assert equivalence that is not rejected by a superiority test, statistical methods known as equivalency tests have been suggested. These methods for equivalency tests are based on the frequency framework; however, there are few such methods in the Bayesian framework. Hence, this article proposes a new index that suggests the equivalency of binomial proportions, which is constructed based on the Bayesian framework. In this study, we provide two methods for calculating the index and compare the probabilities that have been calculated by these two calculation methods. Moreover, we apply this index to the results of actual clinical trials to demonstrate the utility of the index.

  12. Sustainable energy policy for Asia: Mitigating systemic hurdles in a highly dense city

    International Nuclear Information System (INIS)

    Ng, Artie W.; Nathwani, Jatin

    2010-01-01

    Greenhouse gas emission (GHG) has been increasingly a sensitive issue that is across border and impacting global public interests. While the use of renewable energy technology is perceived as a means to enable delivery of emission-free solutions, its penetration into the energy market has not been timely and significant enough as projected in prior studies. This article aims to illustrate some of the critical hurdles as the policy makers start formulating environmentally friendly energy consumption means for the public in Asian economies. In particular, through analyzing the characteristics in the case of Hong Kong, the authors unveil the challenges for this highly dense city to reach a landscape of alternative energy resources for its transition into a sustainable economy. Education and engagement with the public about a sustainable future, alignment of stakeholders' economic interests and absorption capacity of emerging technologies are argued as the three main challenges and initiatives in mitigating the underlying systemic hurdles that remain to be overcome. Observing the current responses to the externalities by the policy makers in Hong Kong, this study articulates the critical challenges to mitigate these specific systemic hurdles embedded in the existing infrastructure of a highly dense city. Possible mitigating measures to enable deployment of integrative sustainable energy solutions in dealing with climate change are discussed. (author)

  13. Lactic Acid Bacteria Selection for Biopreservation as a Part of Hurdle Technology Approach Applied on Seafood

    Directory of Open Access Journals (Sweden)

    Norman Wiernasz

    2017-05-01

    Full Text Available As fragile food commodities, microbial, and organoleptic qualities of fishery and seafood can quickly deteriorate. In this context, microbial quality and security improvement during the whole food processing chain (from catch to plate, using hurdle technology, a combination of mild preserving technologies such as biopreservation, modified atmosphere packaging, and superchilling, are of great interest. As natural flora and antimicrobial metabolites producers, lactic acid bacteria (LAB are commonly studied for food biopreservation. Thirty-five LAB known to possess interesting antimicrobial activity were selected for their potential application as bioprotective agents as a part of hurdle technology applied to fishery products. The selection approach was based on seven criteria including antimicrobial activity, alteration potential, tolerance to chitosan coating, and superchilling process, cross inhibition, biogenic amines production (histamine, tyramine, and antibiotics resistance. Antimicrobial activity was assessed against six common spoiling bacteria in fishery products (Shewanella baltica, Photobacterium phosphoreum, Brochothrix thermosphacta, Lactobacillus sakei, Hafnia alvei, Serratia proteamaculans and one pathogenic bacterium (Listeria monocytogenes in co-culture inhibitory assays miniaturized in 96-well microtiter plates. Antimicrobial activity and spoilage evaluation, both performed in cod and salmon juice, highlighted the existence of sensory signatures and inhibition profiles, which seem to be species related. Finally, six LAB with no unusual antibiotics resistance profile nor histamine production ability were selected as bioprotective agents for further in situ inhibitory assays in cod and salmon based products, alone or in combination with other hurdles (chitosan, modified atmosphere packing, and superchilling.

  14. Revealing Word Order: Using Serial Position in Binomials to Predict Properties of the Speaker

    Science.gov (United States)

    Iliev, Rumen; Smirnova, Anastasia

    2016-01-01

    Three studies test the link between word order in binomials and psychological and demographic characteristics of a speaker. While linguists have already suggested that psychological, cultural and societal factors are important in choosing word order in binomials, the vast majority of relevant research was focused on general factors and on broadly…

  15. Modeling and Predistortion of Envelope Tracking Power Amplifiers using a Memory Binomial Model

    DEFF Research Database (Denmark)

    Tafuri, Felice Francesco; Sira, Daniel; Larsen, Torben

    2013-01-01

    . The model definition is based on binomial series, hence the name of memory binomial model (MBM). The MBM is here applied to measured data-sets acquired from an ET measurement set-up. When used as a PA model the MBM showed an NMSE (Normalized Mean Squared Error) as low as −40dB and an ACEPR (Adjacent Channel...

  16. Adjusted Wald Confidence Interval for a Difference of Binomial Proportions Based on Paired Data

    Science.gov (United States)

    Bonett, Douglas G.; Price, Robert M.

    2012-01-01

    Adjusted Wald intervals for binomial proportions in one-sample and two-sample designs have been shown to perform about as well as the best available methods. The adjusted Wald intervals are easy to compute and have been incorporated into introductory statistics courses. An adjusted Wald interval for paired binomial proportions is proposed here and…

  17. Some normed binomial difference sequence spaces related to the [Formula: see text] spaces.

    Science.gov (United States)

    Song, Meimei; Meng, Jian

    2017-01-01

    The aim of this paper is to introduce the normed binomial sequence spaces [Formula: see text] by combining the binomial transformation and difference operator, where [Formula: see text]. We prove that these spaces are linearly isomorphic to the spaces [Formula: see text] and [Formula: see text], respectively. Furthermore, we compute Schauder bases and the α -, β - and γ -duals of these sequence spaces.

  18. An efficient binomial model-based measure for sequence comparison and its application.

    Science.gov (United States)

    Liu, Xiaoqing; Dai, Qi; Li, Lihua; He, Zerong

    2011-04-01

    Sequence comparison is one of the major tasks in bioinformatics, which could serve as evidence of structural and functional conservation, as well as of evolutionary relations. There are several similarity/dissimilarity measures for sequence comparison, but challenges remains. This paper presented a binomial model-based measure to analyze biological sequences. With help of a random indicator, the occurrence of a word at any position of sequence can be regarded as a random Bernoulli variable, and the distribution of a sum of the word occurrence is well known to be a binomial one. By using a recursive formula, we computed the binomial probability of the word count and proposed a binomial model-based measure based on the relative entropy. The proposed measure was tested by extensive experiments including classification of HEV genotypes and phylogenetic analysis, and further compared with alignment-based and alignment-free measures. The results demonstrate that the proposed measure based on binomial model is more efficient.

  19. FDA Guidance on Biosimilar Interchangeability Elicits Diverse Views: Current and Potential Marketers Complain About Too-High Hurdles.

    Science.gov (United States)

    Barlas, Stephen

    2017-08-01

    Pharmaceutical industry sectors are at odds as the Food and Drug Administration seeks to define "interchangeability" for biosimilars. The battle lines vary by topic, but biosimilar marketers, health plans, and drugstores are generally urging lower hurdles.

  20. FDA Guidance on Biosimilar Interchangeability Elicits Diverse Views: Current and Potential Marketers Complain About Too-High Hurdles

    OpenAIRE

    Barlas, Stephen

    2017-01-01

    Pharmaceutical industry sectors are at odds as the Food and Drug Administration seeks to define “interchangeability” for biosimilars. The battle lines vary by topic, but biosimilar marketers, health plans, and drugstores are generally urging lower hurdles.

  1. Microbial comparative pan-genomics using binomial mixture models

    Directory of Open Access Journals (Sweden)

    Ussery David W

    2009-08-01

    Full Text Available Abstract Background The size of the core- and pan-genome of bacterial species is a topic of increasing interest due to the growing number of sequenced prokaryote genomes, many from the same species. Attempts to estimate these quantities have been made, using regression methods or mixture models. We extend the latter approach by using statistical ideas developed for capture-recapture problems in ecology and epidemiology. Results We estimate core- and pan-genome sizes for 16 different bacterial species. The results reveal a complex dependency structure for most species, manifested as heterogeneous detection probabilities. Estimated pan-genome sizes range from small (around 2600 gene families in Buchnera aphidicola to large (around 43000 gene families in Escherichia coli. Results for Echerichia coli show that as more data become available, a larger diversity is estimated, indicating an extensive pool of rarely occurring genes in the population. Conclusion Analyzing pan-genomics data with binomial mixture models is a way to handle dependencies between genomes, which we find is always present. A bottleneck in the estimation procedure is the annotation of rarely occurring genes.

  2. Dynamic prediction of cumulative incidence functions by direct binomial regression.

    Science.gov (United States)

    Grand, Mia K; de Witte, Theo J M; Putter, Hein

    2018-03-25

    In recent years there have been a series of advances in the field of dynamic prediction. Among those is the development of methods for dynamic prediction of the cumulative incidence function in a competing risk setting. These models enable the predictions to be updated as time progresses and more information becomes available, for example when a patient comes back for a follow-up visit after completing a year of treatment, the risk of death, and adverse events may have changed since treatment initiation. One approach to model the cumulative incidence function in competing risks is by direct binomial regression, where right censoring of the event times is handled by inverse probability of censoring weights. We extend the approach by combining it with landmarking to enable dynamic prediction of the cumulative incidence function. The proposed models are very flexible, as they allow the covariates to have complex time-varying effects, and we illustrate how to investigate possible time-varying structures using Wald tests. The models are fitted using generalized estimating equations. The method is applied to bone marrow transplant data and the performance is investigated in a simulation study. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Confidence limits for parameters of Poisson and binomial distributions

    International Nuclear Information System (INIS)

    Arnett, L.M.

    1976-04-01

    The confidence limits for the frequency in a Poisson process and for the proportion of successes in a binomial process were calculated and tabulated for the situations in which the observed values of the frequency or proportion and an a priori distribution of these parameters are available. Methods are used that produce limits with exactly the stated confidence levels. The confidence interval [a,b] is calculated so that Pr [a less than or equal to lambda less than or equal to b c,μ], where c is the observed value of the parameter, and μ is the a priori hypothesis of the distribution of this parameter. A Bayesian type analysis is used. The intervals calculated are narrower and appreciably different from results, known to be conservative, that are often used in problems of this type. Pearson and Hartley recognized the characteristics of their methods and contemplated that exact methods could someday be used. The calculation of the exact intervals requires involved numerical analyses readily implemented only on digital computers not available to Pearson and Hartley. A Monte Carlo experiment was conducted to verify a selected interval from those calculated. This numerical experiment confirmed the results of the analytical methods and the prediction of Pearson and Hartley that their published tables give conservative results

  4. 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

    2016-01-15

    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 with 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, because 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. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Difference of Sums Containing Products of Binomial Coefficients and Their Logarithms

    National Research Council Canada - National Science Library

    Miller, Allen R; Moskowitz, Ira S

    2005-01-01

    Properties of the difference of two sums containing products of binomial coefficients and their logarithms which arise in the application of Shannon's information theory to a certain class of covert channels are deduced...

  6. Difference of Sums Containing Products of Binomial Coefficients and their Logarithms

    National Research Council Canada - National Science Library

    Miller, Allen R; Moskowitz, Ira S

    2004-01-01

    Properties of the difference of two sums containing products of binomial coefficients and their logarithms which arise in the application of Shannon's information theory to a certain class of covert channels are deduced...

  7. Solvent suppression using phase-modulated binomial-like sequences and applications to diffusion measurements

    Science.gov (United States)

    Zheng, Gang; Torres, Allan M.; Price, William S.

    2008-09-01

    Two phase-modulated binomial-like π pulses have been developed by simultaneously optimizing pulse durations and phases. In combination with excitation sculpting, both of the new binomial-like sequences outperform the well-known 3-9-19 sequence in selectivity and inversion width. The new sequences provide similar selectivity and inversion width to the W5 sequence but with significantly shorter sequence durations. When used in PGSTE-WATERGATE, they afford highly selective solvent suppression in diffusion experiments.

  8. Perbandingan Metode Binomial dan Metode Black-Scholes Dalam Penentuan Harga Opsi

    Directory of Open Access Journals (Sweden)

    Surya Amami Pramuditya

    2016-04-01

    Full Text Available ABSTRAKOpsi adalah kontrak antara pemegang dan penulis  (buyer (holder dan seller (writer di mana penulis (writer memberikan hak (bukan kewajiban kepada holder untuk membeli atau menjual aset dari writer pada harga tertentu (strike atau latihan harga dan pada waktu tertentu dalam waktu (tanggal kadaluwarsa atau jatuh tempo waktu. Ada beberapa cara untuk menentukan harga opsi, diantaranya adalah  Metode Black-Scholes dan Metode Binomial. Metode binomial berasal dari model pergerakan harga saham yang membagi waktu interval [0, T] menjadi n sama panjang. Sedangkan metode Black-Scholes, dimodelkan dengan pergerakan harga saham sebagai suatu proses stokastik. Semakin besar partisi waktu n pada Metode Binomial, maka nilai opsinya akan konvergen ke nilai opsi Metode Black-Scholes.Kata kunci: opsi, Binomial, Black-Scholes.ABSTRACT Option is a contract between the holder and the writer in which the writer gives the right (not the obligation to the holder to buy or sell an asset of a writer at a specified price (the strike or exercise price and at a specified time in the future (expiry date or maturity time. There are several ways to determine the price of options, including the Black-Scholes Method and Binomial Method. Binomial method come from a model of stock price movement that divide time interval [0, T] into n equally long. While the Black Scholes method, the stock price movement is modeled as a stochastic process. More larger the partition of time n in Binomial Method, the value option will converge to the value option in Black-Scholes Method.Key words: Options, Binomial, Black-Scholes

  9. [Evaluation of estimation of prevalence ratio using bayesian log-binomial regression model].

    Science.gov (United States)

    Gao, W L; Lin, H; Liu, X N; Ren, X W; Li, J S; Shen, X P; Zhu, S L

    2017-03-10

    To evaluate the estimation of prevalence ratio ( PR ) by using bayesian log-binomial regression model and its application, we estimated the PR of medical care-seeking prevalence to caregivers' recognition of risk signs of diarrhea in their infants by using bayesian log-binomial regression model in Openbugs software. The results showed that caregivers' recognition of infant' s risk signs of diarrhea was associated significantly with a 13% increase of medical care-seeking. Meanwhile, we compared the differences in PR 's point estimation and its interval estimation of medical care-seeking prevalence to caregivers' recognition of risk signs of diarrhea and convergence of three models (model 1: not adjusting for the covariates; model 2: adjusting for duration of caregivers' education, model 3: adjusting for distance between village and township and child month-age based on model 2) between bayesian log-binomial regression model and conventional log-binomial regression model. The results showed that all three bayesian log-binomial regression models were convergence and the estimated PRs were 1.130(95 %CI : 1.005-1.265), 1.128(95 %CI : 1.001-1.264) and 1.132(95 %CI : 1.004-1.267), respectively. Conventional log-binomial regression model 1 and model 2 were convergence and their PRs were 1.130(95 % CI : 1.055-1.206) and 1.126(95 % CI : 1.051-1.203), respectively, but the model 3 was misconvergence, so COPY method was used to estimate PR , which was 1.125 (95 %CI : 1.051-1.200). In addition, the point estimation and interval estimation of PRs from three bayesian log-binomial regression models differed slightly from those of PRs from conventional log-binomial regression model, but they had a good consistency in estimating PR . Therefore, bayesian log-binomial regression model can effectively estimate PR with less misconvergence and have more advantages in application compared with conventional log-binomial regression model.

  10. Extension of shelf-life of Chickoo slices using hurdle technology

    International Nuclear Information System (INIS)

    Shirodkar, S.; Behere, A.G.; Padwal-Desai, S.R.; Lele, S.S.; Pai, J.S.

    2001-01-01

    An attempt has been made to evolve a protocol to prepare shelf-stable high moisture chickoo slices using Hurdle Technology. The process is based on a slight reduction of water activity (0.98?0.94) by osmosis with a 70 deg Brix sucrose syrup, lowering of pH (5.75 to 4.46) by addition of citric acid, addition of KMS and then subjecting the resulting slices to different doses of gamma radiation ranging from 0.25-1 kGy. Radiation processed chickoo slices remained acceptable for 8 weeks at sub-room temperature (10 ± 2 degC) and for 3 weeks at ambient temperature (28 ± 2 degC) when evaluated by a taste-test panel. (author)

  11. Falls in Swedish hurdle and steeplechase racing and the condition of the track surface

    DEFF Research Database (Denmark)

    Gottlieb-Vedi, M.; Pipper, Christian Bressen

    2015-01-01

    Falls in National Hunt races is a tragic part of the sport. The present study focuses on the relation between racing track conditions and the number of falls in Swedish jump racing. The assumption was that more horses fell on heavy or soft going than on good or firm going. Results from all jump...... races at Täby Racecourse (1992-2001) were recorded. Parameters registered were: type and number of races, racing surface and condition, total time to finish the race, number of starting horses and number of falls. In this period 212 races, corresponding to 1,556 horse starts, were registered. Falls were...... registered in 42 races and in total 61 horses fell. The fall frequency on horse level was significantly higher in steeplechases than in hurdle races (odds ratio =3.69; 95% confidence interval (CI) = 1.99-6.85). For the steeplechases recorded in this study, significantly more falls were seen in long distance...

  12. About ATMPs, SOPs and GMP: The Hurdles to Produce Novel Skin Grafts for Clinical Use.

    Science.gov (United States)

    Hartmann-Fritsch, Fabienne; Marino, Daniela; Reichmann, Ernst

    2016-09-01

    The treatment of severe full-thickness skin defects represents a significant and common clinical problem worldwide. A bio-engineered autologous skin substitute would significantly reduce the problems observed with today's gold standard. Within 15 years of research, the Tissue Biology Research Unit of the University Children's Hospital Zurich has developed autologous tissue-engineered skin grafts based on collagen type I hydrogels. Those products are considered as advanced therapy medicinal products (ATMPs) and are routinely produced for clinical trials in a clean room facility following the guidelines for good manufacturing practice (GMP). This article focuses on hurdles observed for the translation of ATMPs from research into the GMP environment and clinical application. Personalized medicine in the field of rare diseases has great potential. However, ATMPs are mainly developed and promoted by academia, hospitals, and small companies, which face many obstacles such as high financial burdens.

  13. Melhorias em gráficos de controle por atributos para processos de alta qualidade Improved binomial charts for high-quality processes

    Directory of Open Access Journals (Sweden)

    Willem Albers

    2011-06-01

    Full Text Available Geralmente gráficos de controle binomial negativa são utilizados em controle de processo por atributos cuja probabilidade de falha p é relativamente baixa. A decisão de parar ou continuar a produção é feita cada vez que ocorrer r > 1 falhas. Determinar o valor ótimo de r para detectar um determinado aumento de p , requer um alinhamento do gráfico em termos de comportamento do processo sob controle. Neste artigo, gráficos de controle binomial estão sujeitos às mesmas exigências. Estudo subsequente revela que este gráfico apresenta resultados um tanto atraentes sob vários aspectos, como por exemplo, seu poder de detecção. Uma versão do mesmo gráfico empregando estimadores de p também é apresentada no caso de p ser desconhecido.For processes concerning attribute data with (very small failure rate p, often negative binomial control charts are used. The decision whether to stop or continue is made each time r failures have occurred, for some r >1. Finding the optimal r for detecting a given increase of p first requires alignment of the charts in terms of in-control behavior. In the present paper binomial charts are subjected to this same requirement. Subsequent study reveals that the resulting charts are quite attractive in several aspects, such as detection power. For the case of unknown p, an estimated version of the chart is derived and studied.

  14. Binomial Distribution Sample Confidence Intervals Estimation 1. Sampling and Medical Key Parameters Calculation

    Directory of Open Access Journals (Sweden)

    Tudor DRUGAN

    2003-08-01

    Full Text Available The aim of the paper was to present the usefulness of the binomial distribution in studying of the contingency tables and the problems of approximation to normality of binomial distribution (the limits, advantages, and disadvantages. The classification of the medical keys parameters reported in medical literature and expressing them using the contingency table units based on their mathematical expressions restrict the discussion of the confidence intervals from 34 parameters to 9 mathematical expressions. The problem of obtaining different information starting with the computed confidence interval for a specified method, information like confidence intervals boundaries, percentages of the experimental errors, the standard deviation of the experimental errors and the deviation relative to significance level was solves through implementation in PHP programming language of original algorithms. The cases of expression, which contain two binomial variables, were separately treated. An original method of computing the confidence interval for the case of two-variable expression was proposed and implemented. The graphical representation of the expression of two binomial variables for which the variation domain of one of the variable depend on the other variable was a real problem because the most of the software used interpolation in graphical representation and the surface maps were quadratic instead of triangular. Based on an original algorithm, a module was implements in PHP in order to represent graphically the triangular surface plots. All the implementation described above was uses in computing the confidence intervals and estimating their performance for binomial distributions sample sizes and variable.

  15. A fast algorithm for computing binomial coefficients modulo powers of two.

    Science.gov (United States)

    Andreica, Mugurel Ionut

    2013-01-01

    I present a new algorithm for computing binomial coefficients modulo 2N. The proposed method has an O(N3·Multiplication(N)+N4) preprocessing time, after which a binomial coefficient C(P, Q) with 0≤Q≤P≤2N-1 can be computed modulo 2N in O(N2·log(N)·Multiplication(N)) time. Multiplication(N) denotes the time complexity of multiplying two N-bit numbers, which can range from O(N2) to O(N·log(N)·log(log(N))) or better. Thus, the overall time complexity for evaluating M binomial coefficients C(P, Q) modulo 2N with 0≤Q≤P≤2N-1 is O((N3+M·N2·log(N))·Multiplication(N)+N4). After preprocessing, we can actually compute binomial coefficients modulo any 2R with R≤N. For larger values of P and Q, variations of Lucas' theorem must be used first in order to reduce the computation to the evaluation of multiple (O(log(P))) binomial coefficients C(P', Q') (or restricted types of factorials P'!) modulo 2N with 0≤Q'≤P'≤2N-1.

  16. Water-selective excitation of short T2 species with binomial pulses.

    Science.gov (United States)

    Deligianni, Xeni; Bär, Peter; Scheffler, Klaus; Trattnig, Siegfried; Bieri, Oliver

    2014-09-01

    For imaging of fibrous musculoskeletal components, ultra-short echo time methods are often combined with fat suppression. Due to the increased chemical shift, spectral excitation of water might become a favorable option at ultra-high fields. Thus, this study aims to compare and explore short binomial excitation schemes for spectrally selective imaging of fibrous tissue components with short transverse relaxation time (T2 ). Water selective 1-1-binomial excitation is compared with nonselective imaging using a sub-millisecond spoiled gradient echo technique for in vivo imaging of fibrous tissue at 3T and 7T. Simulations indicate a maximum signal loss from binomial excitation of approximately 30% in the limit of very short T2 (0.1 ms), as compared to nonselective imaging; decreasing rapidly with increasing field strength and increasing T2 , e.g., to 19% at 3T and 10% at 7T for T2 of 1 ms. In agreement with simulations, a binomial phase close to 90° yielded minimum signal loss: approximately 6% at 3T and close to 0% at 7T for menisci, and for ligaments 9% and 13%, respectively. Overall, for imaging of short-lived T2 components, short 1-1 binomial excitation schemes prove to offer marginal signal loss especially at ultra-high fields with overall improved scanning efficiency. Copyright © 2013 Wiley Periodicals, Inc.

  17. Possibility and Challenges of Conversion of Current Virus Species Names to Linnaean Binomials

    Energy Technology Data Exchange (ETDEWEB)

    Postler, Thomas S.; Clawson, Anna N.; Amarasinghe, Gaya K.; Basler, Christopher F.; Bavari, Sbina; Benkő, Mária; Blasdell, Kim R.; Briese, Thomas; Buchmeier, Michael J.; Bukreyev, Alexander; Calisher, Charles H.; Chandran, Kartik; Charrel, Rémi; Clegg, Christopher S.; Collins, Peter L.; Juan Carlos, De La Torre; Derisi, Joseph L.; Dietzgen, Ralf G.; Dolnik, Olga; Dürrwald, Ralf; Dye, John M.; Easton, Andrew J.; Emonet, Sébastian; Formenty, Pierre; Fouchier, Ron A. M.; Ghedin, Elodie; Gonzalez, Jean-Paul; Harrach, Balázs; Hewson, Roger; Horie, Masayuki; Jiāng, Dàohóng; Kobinger, Gary; Kondo, Hideki; Kropinski, Andrew M.; Krupovic, Mart; Kurath, Gael; Lamb, Robert A.; Leroy, Eric M.; Lukashevich, Igor S.; Maisner, Andrea; Mushegian, Arcady R.; Netesov, Sergey V.; Nowotny, Norbert; Patterson, Jean L.; Payne, Susan L.; PaWeska, Janusz T.; Peters, Clarence J.; Radoshitzky, Sheli R.; Rima, Bertus K.; Romanowski, Victor; Rubbenstroth, Dennis; Sabanadzovic, Sead; Sanfaçon, Hélène; Salvato, Maria S.; Schwemmle, Martin; Smither, Sophie J.; Stenglein, Mark D.; Stone, David M.; Takada, Ayato; Tesh, Robert B.; Tomonaga, Keizo; Tordo, Noël; Towner, Jonathan S.; Vasilakis, Nikos; Volchkov, Viktor E.; Wahl-Jensen, Victoria; Walker, Peter J.; Wang, Lin-Fa; Varsani, Arvind; Whitfield, Anna E.; Zerbini, F. Murilo; Kuhn, Jens H.

    2016-10-22

    Botanical, mycological, zoological, and prokaryotic species names follow the Linnaean format, consisting of an italicized Latinized binomen with a capitalized genus name and a lower case species epithet (e.g., Homo sapiens). Virus species names, however, do not follow a uniform format, and, even when binomial, are not Linnaean in style. In this thought exercise, we attempted to convert all currently official names of species included in the virus family Arenaviridae and the virus order Mononegavirales to Linnaean binomials, and to identify and address associated challenges and concerns. Surprisingly, this endeavor was not as complicated or time-consuming as even the authors of this article expected when conceiving the experiment. [Arenaviridae; binomials; ICTV; International Committee on Taxonomy of Viruses; Mononegavirales; virus nomenclature; virus taxonomy.

  18. Entanglement properties between two atoms in the binomial optical field interacting with two entangled atoms

    International Nuclear Information System (INIS)

    Liu Tang-Kun; Zhang Kang-Long; Tao Yu; Shan Chuan-Jia; Liu Ji-Bing

    2016-01-01

    The temporal evolution of the degree of entanglement between two atoms in a system of the binomial optical field interacting with two arbitrary entangled atoms is investigated. The influence of the strength of the dipole–dipole interaction between two atoms, probabilities of the Bernoulli trial, and particle number of the binomial optical field on the temporal evolution of the atomic entanglement are discussed. The result shows that the two atoms are always in the entanglement state. Moreover, if and only if the two atoms are initially in the maximally entangled state, the entanglement evolution is not affected by the parameters, and the degree of entanglement is always kept as 1. (paper)

  19. On extinction time of a generalized endemic chain-binomial model.

    Science.gov (United States)

    Aydogmus, Ozgur

    2016-09-01

    We considered a chain-binomial epidemic model not conferring immunity after infection. Mean field dynamics of the model has been analyzed and conditions for the existence of a stable endemic equilibrium are determined. The behavior of the chain-binomial process is probabilistically linked to the mean field equation. As a result of this link, we were able to show that the mean extinction time of the epidemic increases at least exponentially as the population size grows. We also present simulation results for the process to validate our analytical findings. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Binomial confidence intervals for testing non-inferiority or superiority: a practitioner's dilemma.

    Science.gov (United States)

    Pradhan, Vivek; Evans, John C; Banerjee, Tathagata

    2016-08-01

    In testing for non-inferiority or superiority in a single arm study, the confidence interval of a single binomial proportion is frequently used. A number of such intervals are proposed in the literature and implemented in standard software packages. Unfortunately, use of different intervals leads to conflicting conclusions. Practitioners thus face a serious dilemma in deciding which one to depend on. Is there a way to resolve this dilemma? We address this question by investigating the performances of ten commonly used intervals of a single binomial proportion, in the light of two criteria, viz., coverage and expected length of the interval. © The Author(s) 2013.

  1. How to overcome hurdles in opiate substitution treatment? A qualitative study with general practitioners in Belgium.

    Science.gov (United States)

    Fraeyman, Jessica; Symons, Linda; Van Royen, Paul; Van Hal, Guido; Peremans, Lieve

    2016-06-01

    Opiate substitution treatment (OST) is the administration of opioids (methadone or buprenorphine) under medical supervision for opiate addiction. Several studies indicate a large unmet need for OST in general practice in Antwerp, Belgium. Some hurdles remain before GPs engage in OST prescribing. Formulate recommendations to increase engagement of GPs in OST, applicable to Belgium and beyond. In 2009, an exploratory qualitative research was performed using focus group discussions and interviews with GPs. During data collection and analysis, purposive sampling, open and axial coding was applied. The script was composed around the advantages, disadvantages and conditions of engaging in OST in general practice. We conducted six focus groups and two interviews, with GPs experienced in prescribing OST (n = 13), inexperienced GPs (n = 13), and physicians from addiction centres (n = 5). Overall, GPs did not seem very willing to prescribe OST for opiate users. A lack of knowledge about OST and misbehaving patients creates anxiety and makes the GPs reluctant to learn more about OST. The GPs refer to a lack of collaboration with the addiction centres and a need of support (from either addiction centres or experienced GP-colleagues for advice). Important conditions for OST are acceptance of only stable opiate users and more support in emergencies. Increasing GPs' knowledge about OST and improving collaboration with addiction centres are essential to increase the uptake of OST in general practice. Special attention could be paid to the role of more experienced colleagues who can act as advising physicians for inexperienced GPs.

  2. Effects of gamma irradiation and silver nano particles on microbiological characteristics of saffron, using hurdle technology.

    Science.gov (United States)

    Hamid Sales, E; Motamedi Sedeh, F; Rajabifar, S

    2012-03-01

    Saffron, a plant from the Iridaceae family, is the world's most expensive spice. Gamma irradiation and silver nano particles whose uses are gradually increasing worldwide, have positive effects on preventing decay by sterilizing the microorganisms and by improving the safety without compromising the nutritional properties and sensory quality of the foods. In the present study combination effects of gamma irradiation and silver nano particles packaging on the microbial contamination of saffron were considered during storage. A combination of hurdles can ensure stability and microbial safety of foods. For this purpose, saffron samples were packaged by Poly Ethylene films that posses up to 300 ppm nano silver particles as antimicrobial agents and then irradiated in cobalt-60 irradiator (gamma cell PX30, dose rate 0.55 Gry/Sec) to 0, 1, 2,3 and 4 kGy at room temperature. The antimicrobial activities against Total Aerobic Mesophilic Bacteria, Entrobacteriace, Escherichia Coli and Clostridium Perfringines were higher in the irradiated samples, demonstrating the inhibition zone for their growth. Irradiation of the saffron samples packaged by Poly Ethylene films with nano silver particles showed the best results for decreasing microbial contamination at 2 kGy and for Poly Ethylene films without silver nano particles; it was 4 kGy.

  3. Semantic Web for Chemical Genomics – need, how to, and hurdles

    Directory of Open Access Journals (Sweden)

    Talapady Bhat

    2007-08-01

    Full Text Available Semantic Web has been often suggested as the information technology solution to the growing problem in managing the millions of data points generated by modern science such as nanotechnology and high through-put screening for drugs. However, the progress towards this vision envisaged by the W3C has been very limited. Here we discuss –some of the obstacles to the realization of this vision and we make some suggestions as to how one may overcome some of these hurdles? Here we discuss some of these issues and present thoughts on an alternative method to Semantic Web that is less drastic in requirements. This method does not require the use of RDF and Protege, and it works in an environment currently used by the chemical and biological database providers. In our method one attempts to use as many components as possible from the tools already used by the database providers and one brings in far fewer new tools and techniques compared to the method that use RDF or Protégé. Our method uses a standard database environment and web tools rather than the RDF and Protégé to manage user interface and the data is held in a database rather than using RDF. This method shifts the task of building Semantic knowledge-base and ontology from RDF and Protégé to a SQL based database environment.

  4. A binomial random sum of present value models in investment analysis

    OpenAIRE

    Βουδούρη, Αγγελική; Ντζιαχρήστος, Ευάγγελος

    1997-01-01

    Stochastic present value models have been widely adopted in financial theory and practice and play a very important role in capital budgeting and profit planning. The purpose of this paper is to introduce a binomial random sum of stochastic present value models and offer an application in investment analysis.

  5. Topology of unitary groups and the prime orders of binomial coefficients

    Science.gov (United States)

    Duan, HaiBao; Lin, XianZu

    2017-09-01

    Let $c:SU(n)\\rightarrow PSU(n)=SU(n)/\\mathbb{Z}_{n}$ be the quotient map of the special unitary group $SU(n)$ by its center subgroup $\\mathbb{Z}_{n}$. We determine the induced homomorphism $c^{\\ast}:$ $H^{\\ast}(PSU(n))\\rightarrow H^{\\ast}(SU(n))$ on cohomologies by computing with the prime orders of binomial coefficients

  6. A Bayesian Approach to Functional Mixed Effect Modeling for Longitudinal Data with Binomial Outcomes

    Science.gov (United States)

    Kliethermes, Stephanie; Oleson, Jacob

    2014-01-01

    Longitudinal growth patterns are routinely seen in medical studies where individual and population growth is followed over a period of time. Many current methods for modeling growth presuppose a parametric relationship between the outcome and time (e.g., linear, quadratic); however, these relationships may not accurately capture growth over time. Functional mixed effects (FME) models provide flexibility in handling longitudinal data with nonparametric temporal trends. Although FME methods are well-developed for continuous, normally distributed outcome measures, nonparametric methods for handling categorical outcomes are limited. We consider the situation with binomially distributed longitudinal outcomes. Although percent correct data can be modeled assuming normality, estimates outside the parameter space are possible and thus estimated curves can be unrealistic. We propose a binomial FME model using Bayesian methodology to account for growth curves with binomial (percentage) outcomes. The usefulness of our methods is demonstrated using a longitudinal study of speech perception outcomes from cochlear implant users where we successfully model both the population and individual growth trajectories. Simulation studies also advocate the usefulness of the binomial model particularly when outcomes occur near the boundary of the probability parameter space and in situations with a small number of trials. PMID:24723495

  7. A mixed-binomial model for Likert-type personality measures.

    Science.gov (United States)

    Allik, Jüri

    2014-01-01

    Personality measurement is based on the idea that values on an unobservable latent variable determine the distribution of answers on a manifest response scale. Typically, it is assumed in the Item Response Theory (IRT) that latent variables are related to the observed responses through continuous normal or logistic functions, determining the probability with which one of the ordered response alternatives on a Likert-scale item is chosen. Based on an analysis of 1731 self- and other-rated responses on the 240 NEO PI-3 questionnaire items, it was proposed that a viable alternative is a finite number of latent events which are related to manifest responses through a binomial function which has only one parameter-the probability with which a given statement is approved. For the majority of items, the best fit was obtained with a mixed-binomial distribution, which assumes two different subpopulations who endorse items with two different probabilities. It was shown that the fit of the binomial IRT model can be improved by assuming that about 10% of random noise is contained in the answers and by taking into account response biases toward one of the response categories. It was concluded that the binomial response model for the measurement of personality traits may be a workable alternative to the more habitual normal and logistic IRT models.

  8. Confidence Intervals for Weighted Composite Scores under the Compound Binomial Error Model

    Science.gov (United States)

    Kim, Kyung Yong; Lee, Won-Chan

    2018-01-01

    Reporting confidence intervals with test scores helps test users make important decisions about examinees by providing information about the precision of test scores. Although a variety of estimation procedures based on the binomial error model are available for computing intervals for test scores, these procedures assume that items are randomly…

  9. Binomial Coefficients Modulo a Prime--A Visualization Approach to Undergraduate Research

    Science.gov (United States)

    Bardzell, Michael; Poimenidou, Eirini

    2011-01-01

    In this article we present, as a case study, results of undergraduate research involving binomial coefficients modulo a prime "p." We will discuss how undergraduates were involved in the project, even with a minimal mathematical background beforehand. There are two main avenues of exploration described to discover these binomial…

  10. Computational results on the compound binomial risk model with nonhomogeneous claim occurrences

    NARCIS (Netherlands)

    Tuncel, A.; Tank, F.

    2013-01-01

    The aim of this paper is to give a recursive formula for non-ruin (survival) probability when the claim occurrences are nonhomogeneous in the compound binomial risk model. We give recursive formulas for non-ruin (survival) probability and for distribution of the total number of claims under the

  11. Determining order-up-to levels under periodic review for compound binomial (intermittent) demand

    NARCIS (Netherlands)

    Teunter, R. H.; Syntetos, A. A.; Babai, M. Z.

    2010-01-01

    We propose a new method for determining order-up-to levels for intermittent demand items in a periodic review system. Contrary to existing methods, we exploit the intermittent character of demand by modelling lead time demand as a compound binomial process. in an extensive numerical study using

  12. A Bayesian approach to functional mixed-effects modeling for longitudinal data with binomial outcomes.

    Science.gov (United States)

    Kliethermes, Stephanie; Oleson, Jacob

    2014-08-15

    Longitudinal growth patterns are routinely seen in medical studies where individual growth and population growth are followed up over a period of time. Many current methods for modeling growth presuppose a parametric relationship between the outcome and time (e.g., linear and quadratic); however, these relationships may not accurately capture growth over time. Functional mixed-effects (FME) models provide flexibility in handling longitudinal data with nonparametric temporal trends. Although FME methods are well developed for continuous, normally distributed outcome measures, nonparametric methods for handling categorical outcomes are limited. We consider the situation with binomially distributed longitudinal outcomes. Although percent correct data can be modeled assuming normality, estimates outside the parameter space are possible, and thus, estimated curves can be unrealistic. We propose a binomial FME model using Bayesian methodology to account for growth curves with binomial (percentage) outcomes. The usefulness of our methods is demonstrated using a longitudinal study of speech perception outcomes from cochlear implant users where we successfully model both the population and individual growth trajectories. Simulation studies also advocate the usefulness of the binomial model particularly when outcomes occur near the boundary of the probability parameter space and in situations with a small number of trials. Copyright © 2014 John Wiley & Sons, Ltd.

  13. Joint Analysis of Binomial and Continuous Traits with a Recursive Model

    DEFF Research Database (Denmark)

    Varona, Louis; Sorensen, Daniel

    2014-01-01

    This work presents a model for the joint analysis of a binomial and a Gaussian trait using a recursive parametrization that leads to a computationally efficient implementation. The model is illustrated in an analysis of mortality and litter size in two breeds of Danish pigs, Landrace and Yorkshir...

  14. Generating and revealing a quantum superposition of electromagnetic-field binomial states in a cavity

    International Nuclear Information System (INIS)

    Lo Franco, R.; Compagno, G.; Messina, A.; Napoli, A.

    2007-01-01

    We introduce the N-photon quantum superposition of two orthogonal generalized binomial states of an electromagnetic field. We then propose, using resonant atom-cavity interactions, nonconditional schemes to generate and reveal such a quantum superposition for the two-photon case in a single-mode high-Q cavity. We finally discuss the implementation of the proposed schemes

  15. Learning Binomial Probability Concepts with Simulation, Random Numbers and a Spreadsheet

    Science.gov (United States)

    Rochowicz, John A., Jr.

    2005-01-01

    This paper introduces the reader to the concepts of binomial probability and simulation. A spreadsheet is used to illustrate these concepts. Random number generators are great technological tools for demonstrating the concepts of probability. Ideas of approximation, estimation, and mathematical usefulness provide numerous ways of learning…

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

    Science.gov (United States)

    Griffiths, Martin

    2013-01-01

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

  17. Evaluating components of dental care utilization among adults with diabetes and matched controls via hurdle models

    Science.gov (United States)

    2012-01-01

    Background About one-third of adults with diabetes have severe oral complications. However, limited previous research has investigated dental care utilization associated with diabetes. This project had two purposes: to develop a methodology to estimate dental care utilization using claims data and to use this methodology to compare utilization of dental care between adults with and without diabetes. Methods Data included secondary enrollment and demographic data from Washington Dental Service (WDS) and Group Health Cooperative (GH), clinical data from GH, and dental-utilization data from WDS claims during 2002–2006. Dental and medical records from WDS and GH were linked for enrolees continuously and dually insured during the study. We employed hurdle models in a quasi-experimental setting to assess differences between adults with and without diabetes in 5-year cumulative utilization of dental services. Propensity score matching adjusted for differences in baseline covariates between the two groups. Results We found that adults with diabetes had lower odds of visiting a dentist (OR = 0.74, p dental visit, diabetes patients had lower odds of receiving prophylaxes (OR = 0.77), fillings (OR = 0.80) and crowns (OR = 0.84) (p diabetes are less likely to use dental services. Those who do are less likely to use preventive care and more likely to receive periodontal care and tooth-extractions. Future research should address the possible effectiveness of additional prevention in reducing subsequent severe oral disease in patients with diabetes. PMID:22776352

  18. Evaluating components of dental care utilization among adults with diabetes and matched controls via hurdle models

    Directory of Open Access Journals (Sweden)

    Chaudhari Monica

    2012-07-01

    Full Text Available Abstract Background About one-third of adults with diabetes have severe oral complications. However, limited previous research has investigated dental care utilization associated with diabetes. This project had two purposes: to develop a methodology to estimate dental care utilization using claims data and to use this methodology to compare utilization of dental care between adults with and without diabetes. Methods Data included secondary enrollment and demographic data from Washington Dental Service (WDS and Group Health Cooperative (GH, clinical data from GH, and dental-utilization data from WDS claims during 2002–2006. Dental and medical records from WDS and GH were linked for enrolees continuously and dually insured during the study. We employed hurdle models in a quasi-experimental setting to assess differences between adults with and without diabetes in 5-year cumulative utilization of dental services. Propensity score matching adjusted for differences in baseline covariates between the two groups. Results We found that adults with diabetes had lower odds of visiting a dentist (OR = 0.74, p  0.001. Among those with a dental visit, diabetes patients had lower odds of receiving prophylaxes (OR = 0.77, fillings (OR = 0.80 and crowns (OR = 0.84 (p 0.005 for all and higher odds of receiving periodontal maintenance (OR = 1.24, non-surgical periodontal procedures (OR = 1.30, extractions (OR = 1.38 and removable prosthetics (OR = 1.36 (p  Conclusions Patients with diabetes are less likely to use dental services. Those who do are less likely to use preventive care and more likely to receive periodontal care and tooth-extractions. Future research should address the possible effectiveness of additional prevention in reducing subsequent severe oral disease in patients with diabetes.

  19. Overcoming hurdles in translating visual search research between the lab and the field.

    Science.gov (United States)

    Clark, Kait; Cain, Matthew S; Adamo, Stephen H; Mitroff, Stephen R

    2012-01-01

    Research in visual search can be vital to improving performance in careers such as radiology and airport security screening. In these applied, or "field," searches, accuracy is critical, and misses are potentially fatal; however, despite the importance of performing optimally, radiological and airport security searches are nevertheless flawed. Extensive basic research in visual search has revealed cognitive mechanisms responsible for successful visual search as well as a variety of factors that tend to inhibit or improve performance. Ideally, the knowledge gained from such laboratory-based research could be directly applied to field searches, but several obstacles stand in the way of straightforward translation; the tightly controlled visual searches performed in the lab can be drastically different from field searches. For example, they can differ in terms of the nature of the stimuli, the environment in which the search is taking place, and the experience and characteristics of the searchers themselves. The goal of this chapter is to discuss these differences and how they can present hurdles to translating lab-based research to field-based searches. Specifically, most search tasks in the lab entail searching for only one target per trial, and the targets occur relatively frequently, but field searches may contain an unknown and unlimited number of targets, and the occurrence of targets can be rare. Additionally, participants in lab-based search experiments often perform under neutral conditions and have no formal training or experience in search tasks; conversely, career searchers may be influenced by the motivation to perform well or anxiety about missing a target, and they have undergone formal training and accumulated significant experience searching. This chapter discusses recent work that has investigated the impacts of these differences to determine how each factor can influence search performance. Knowledge gained from the scientific exploration of search

  20. Non-viral gene delivery systems: hurdles for bench-to-bedside transformation.

    Science.gov (United States)

    Helal, N A; Osami, A; Helmy, A; McDonald, T; Shaaban, L A; Nounou, M I

    2017-11-01

    Biologist and Nobel Prize winner James Watson's quote, "We used to think that our fate was in our stars, but now we know that, in large measure, our fate is in our genes", represents the initial food for thought that revolutionized the way medications and active pharmaceutical ingredients are defined (Rocholl 1996). This fate engraved in the genetic material, as mentioned in Watson's quote, fueled a tremendous revolution wave in gene therapy. Gene therapy is a promising technology for treating genetic and acquired diseases by modulating the expression of a specific gene in the pathological cells. This is achieved by introducing a DNA sequence or other nucleic acid material or oligonucleotides to the target cell (Kay, 2011). Moreover, gene therapy contributes to correction of genetic defects, expression of therapeutic proteins, and inhibition of the synthesis of malignant proteins. In this review article, different non-viral gene delivery systems and their applications are discussed in detail. We reviewed and tabulated over 90 papers and 50 patents from 2006 to date discussing non-viral gene delivery technologies, innovation, and bench-to-bedside transformation. Furthermore, we are going to shed light on the lack of standardization in the design and characterization of non-viral gene delivery systems worldwide, which is a major concern in this research's field. This review would aid in getting an eagle eye view through non-viral gene delivery technologies during the past 20 years. Such a view, capturing the advances, the hurdles, and experimental details, would aid expert researchers in tuning their experimentation strategies and help newcomers better initially design their studies to generate solid and comprehensive results that can be reliable and reproducible.

  1. Machine learning and hurdle models for improving regional predictions of stream water acid neutralizing capacity

    Science.gov (United States)

    Povak, Nicholas A.; Hessburg, Paul F.; Reynolds, Keith M.; Sullivan, Timothy J.; McDonnell, Todd C.; Salter, R. Brion

    2013-06-01

    In many industrialized regions of the world, atmospherically deposited sulfur derived from industrial, nonpoint air pollution sources reduces stream water quality and results in acidic conditions that threaten aquatic resources. Accurate maps of predicted stream water acidity are an essential aid to managers who must identify acid-sensitive streams, potentially affected biota, and create resource protection strategies. In this study, we developed correlative models to predict the acid neutralizing capacity (ANC) of streams across the southern Appalachian Mountain region, USA. Models were developed using stream water chemistry data from 933 sampled locations and continuous maps of pertinent environmental and climatic predictors. Environmental predictors were averaged across the upslope contributing area for each sampled stream location and submitted to both statistical and machine-learning regression models. Predictor variables represented key aspects of the contributing geology, soils, climate, topography, and acidic deposition. To reduce model error rates, we employed hurdle modeling to screen out well-buffered sites and predict continuous ANC for the remainder of the stream network. Models predicted acid-sensitive streams in forested watersheds with small contributing areas, siliceous lithologies, cool and moist environments, low clay content soils, and moderate or higher dry sulfur deposition. Our results confirmed findings from other studies and further identified several influential climatic variables and variable interactions. Model predictions indicated that one quarter of the total stream network was sensitive to additional sulfur inputs (i.e., ANC < 100 µeq L-1), while <10% displayed much lower ANC (<50 µeq L-1). These methods may be readily adapted in other regions to assess stream water quality and potential biotic sensitivity to acidic inputs.

  2. Four hurdles for conservation on private land: the case of the golden lion tamarin, Atlantic Forest, Brazil.

    Directory of Open Access Journals (Sweden)

    Ralf Christopher Buckley

    2015-08-01

    Full Text Available Many threatened species worldwide rely on patches of remnant vegetation in private landholdings. To establish private reserves that contribute effectively to conservation involves a wide range of complex and interacting ecological, legal, social and financial factors. These can be seen as a series of successive hurdles, each with multiple bars, which must all be surmounted. The golden lion tamarin, Leontopithecus rosalia, is restricted to the Atlantic Forest biome in the state of Rio de Janeiro, Brazil. This forest is largely cleared. There are many small remnant patches on private lands, able to support tamarins. Local NGO’s have successfully used limited funds to contribute to tamarin conservation in a highly cost effective way. We examined the mechanisms by analysing documents and interviewing landholders and other stakeholders. We found that the local NGOs successfully identified landholdings where ecological, legal, social and some financial hurdles had already been crossed, and helped landholders over the final financial hurdle by funding critical cost components. This cost <5% of the price of outright land purchase. This approach is scaleable for golden lion tamarin elsewhere within the Atlantic Forest biome, and applicable for other species and ecosystems worldwide.

  3. When negation is not negation

    OpenAIRE

    Milicevic, Nataša

    2008-01-01

    In this paper I will discuss the formation of different types of yes/no questions in Serbian (examples in (1)), focusing on the syntactically and semantically puzzling example (1d), which involves the negative auxiliary inversion. Although there is a negative marker on the fronted auxiliary, the construction does not involve sentential negation. This coincides with the fact that the negative quantifying NPIs cannot be licensed. The question formation and sentential negation have similar synta...

  4. Possibility and challenges of conversion of current virus species names to Linnaean binomials

    Science.gov (United States)

    Thomas, Postler; Clawson, Anna N.; Amarasinghe, Gaya K.; Basler, Christopher F.; Bavari, Sina; Benko, Maria; Blasdell, Kim R.; Briese, Thomas; Buchmeier, Michael J.; Bukreyev, Alexander; Calisher, Charles H.; Chandran, Kartik; Charrel, Remi; Clegg, Christopher S.; Collins, Peter L.; De la Torre, Juan Carlos; DeRisi, Joseph L.; Dietzgen, Ralf G.; Dolnik, Olga; Durrwald, Ralf; Dye, John M.; Easton, Andrew J.; Emonet, Sebastian; Formenty, Pierre; Fouchier, Ron A. M.; Ghedin, Elodie; Gonzalez, Jean-Paul; Harrach, Balazs; Hewson, Roger; Horie, Masayuki; Jiang, Daohong; Kobinger, Gary P.; Kondo, Hideki; Kropinski, Andrew; Krupovic, Mart; Kurath, Gael; Lamb, Robert A.; Leroy, Eric M.; Lukashevich, Igor S.; Maisner, Andrea; Mushegian, Arcady; Netesov, Sergey V.; Nowotny, Norbert; Patterson, Jean L.; Payne, Susan L.; Paweska, Janusz T.; Peters, C.J.; Radoshitzky, Sheli; Rima, Bertus K.; Romanowski, Victor; Rubbenstroth, Dennis; Sabanadzovic, Sead; Sanfacon, Helene; Salvato , Maria; Schwemmle, Martin; Smither, Sophie J.; Stenglein, Mark; Stone, D.M.; Takada , Ayato; Tesh, Robert B.; Tomonaga, Keizo; Tordo, N.; Towner, Jonathan S.; Vasilakis, Nikos; Volchkov, Victor E.; Jensen, Victoria; Walker, Peter J.; Wang, Lin-Fa; Varsani, Arvind; Whitfield , Anna E.; Zerbini, Francisco Murilo; Kuhn, Jens H.

    2017-01-01

    Botanical, mycological, zoological, and prokaryotic species names follow the Linnaean format, consisting of an italicized Latinized binomen with a capitalized genus name and a lower case species epithet (e.g., Homo sapiens). Virus species names, however, do not follow a uniform format, and, even when binomial, are not Linnaean in style. In this thought exercise, we attempted to convert all currently official names of species included in the virus family Arenaviridae and the virus order Mononegavirales to Linnaean binomials, and to identify and address associated challenges and concerns. Surprisingly, this endeavor was not as complicated or time-consuming as even the authors of this article expected when conceiving the experiment.

  5. The option to expand a project: its assessment with the binomial options pricing model

    Directory of Open Access Journals (Sweden)

    Salvador Cruz Rambaud

    Full Text Available Traditional methods of investment appraisal, like the Net Present Value, are not able to include the value of the operational flexibility of the project. In this paper, real options, and more specifically the option to expand, are assumed to be included in the project information in addition to the expected cash flows. Thus, to calculate the total value of the project, we are going to apply the methodology of the Net Present Value to the different scenarios derived from the existence of the real option to expand. Taking into account the analogy between real and financial options, the value of including an option to expand is explored by using the binomial options pricing model. In this way, estimating the value of the option to expand is a tool which facilitates the control of the uncertainty element implicit in the project. Keywords: Real options, Option to expand, Binomial options pricing model, Investment project appraisal

  6. Comparison of multinomial and binomial proportion methods for analysis of multinomial count data.

    Science.gov (United States)

    Galyean, M L; Wester, D B

    2010-10-01

    Simulation methods were used to generate 1,000 experiments, each with 3 treatments and 10 experimental units/treatment, in completely randomized (CRD) and randomized complete block designs. Data were counts in 3 ordered or 4 nominal categories from multinomial distributions. For the 3-category analyses, category probabilities were 0.6, 0.3, and 0.1, respectively, for 2 of the treatments, and 0.5, 0.35, and 0.15 for the third treatment. In the 4-category analysis (CRD only), probabilities were 0.3, 0.3, 0.2, and 0.2 for treatments 1 and 2 vs. 0.4, 0.4, 0.1, and 0.1 for treatment 3. The 3-category data were analyzed with generalized linear mixed models as an ordered multinomial distribution with a cumulative logit link or by regrouping the data (e.g., counts in 1 category/sum of counts in all categories), followed by analysis of single categories as binomial proportions. Similarly, the 4-category data were analyzed as a nominal multinomial distribution with a glogit link or by grouping data as binomial proportions. For the 3-category CRD analyses, empirically determined type I error rates based on pair-wise comparisons (F- and Wald chi(2) tests) did not differ between multinomial and individual binomial category analyses with 10 (P = 0.38 to 0.60) or 50 (P = 0.19 to 0.67) sampling units/experimental unit. When analyzed as binomial proportions, power estimates varied among categories, with analysis of the category with the greatest counts yielding power similar to the multinomial analysis. Agreement between methods (percentage of experiments with the same results for the overall test for treatment effects) varied considerably among categories analyzed and sampling unit scenarios for the 3-category CRD analyses. Power (F-test) was 24.3, 49.1, 66.9, 83.5, 86.8, and 99.7% for 10, 20, 30, 40, 50, and 100 sampling units/experimental unit for the 3-category multinomial CRD analyses. Results with randomized complete block design simulations were similar to those with the CRD

  7. A Bayesian non-inferiority test for two independent binomial proportions.

    Science.gov (United States)

    Kawasaki, Yohei; Miyaoka, Etsuo

    2013-01-01

    In drug development, non-inferiority tests are often employed to determine the difference between two independent binomial proportions. Many test statistics for non-inferiority are based on the frequentist framework. However, research on non-inferiority in the Bayesian framework is limited. In this paper, we suggest a new Bayesian index τ = P(π₁  > π₂-Δ₀|X₁, X₂), where X₁ and X₂ denote binomial random variables for trials n1 and n₂, and parameters π₁ and π₂ , respectively, and the non-inferiority margin is Δ₀> 0. We show two calculation methods for τ, an approximate method that uses normal approximation and an exact method that uses an exact posterior PDF. We compare the approximate probability with the exact probability for τ. Finally, we present the results of actual clinical trials to show the utility of index τ. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Application of a binomial cusum control chart to monitor one drinking water indicator

    Directory of Open Access Journals (Sweden)

    Elisa Henning

    2014-02-01

    Full Text Available The aim of this study is to analyze the use of a binomial cumulative sum chart (CUSUM to monitor the presence of total coliforms, biological indicators of quality of water supplies in water treatment processes. The sample series were monthly taken from a water treatment plant and were analyzed from 2007 to 2009. The statistical treatment of the data was performed using GNU R, and routines were created for the approximation of the upper limit of the binomial CUSUM chart. Furthermore, a comparative study was conducted to investigate whether there is a significant difference in sensitivity between the use of CUSUM and the traditional Shewhart chart, the most commonly used chart in process monitoring. The results obtained demonstrate that this study was essential for making the right choice in selecting a chart for the statistical analysis of this process.

  9. Nested (inverse) binomial sums and new iterated integrals for massive Feynman diagrams

    International Nuclear Information System (INIS)

    Ablinger, Jakob; Schneider, Carsten; Bluemlein, Johannes; Raab, Clemens G.

    2014-07-01

    Nested sums containing binomial coefficients occur in the computation of massive operatormatrix elements. Their associated iterated integrals lead to alphabets including radicals, for which we determined a suitable basis. We discuss algorithms for converting between sum and integral representations, mainly relying on the Mellin transform. To aid the conversion we worked out dedicated rewrite rules, based on which also some general patterns emerging in the process can be obtained.

  10. Study on Emission Measurement of Vehicle on Road Based on Binomial Logit Model

    OpenAIRE

    Aly, Sumarni Hamid; Selintung, Mary; Ramli, Muhammad Isran; Sumi, Tomonori

    2011-01-01

    This research attempts to evaluate emission measurement of on road vehicle. In this regard, the research develops failure probability model of vehicle emission test for passenger car which utilize binomial logit model. The model focuses on failure of CO and HC emission test for gasoline cars category and Opacity emission test for diesel-fuel cars category as dependent variables, while vehicle age, engine size, brand and type of the cars as independent variables. In order to imp...

  11. Computation of Clebsch-Gordan and Gaunt coefficients using binomial coefficients

    International Nuclear Information System (INIS)

    Guseinov, I.I.; Oezmen, A.; Atav, Ue

    1995-01-01

    Using binomial coefficients the Clebsch-Gordan and Gaunt coefficients were calculated for extremely large quantum numbers. The main advantage of this approach is directly calculating these coefficients, instead of using recursion relations. Accuracy of the results is quite high for quantum numbers l 1 , and l 2 up to 100. Despite direct calculation, the CPU times are found comparable with those given in the related literature. 11 refs., 1 fig., 2 tabs

  12. Generalized harmonic, cyclotomic, and binomial sums, their polylogarithms and special numbers

    Energy Technology Data Exchange (ETDEWEB)

    Ablinger, J.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation (RISC); Bluemlein, J. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2013-10-15

    A survey is given on mathematical structures which emerge in multi-loop Feynman diagrams. These are multiply nested sums, and, associated to them by an inverse Mellin transform, specific iterated integrals. Both classes lead to sets of special numbers. Starting with harmonic sums and polylogarithms we discuss recent extensions of these quantities as cyclotomic, generalized (cyclotomic), and binomially weighted sums, associated iterated integrals and special constants and their relations.

  13. Estimasi Harga Multi-State European Call Option Menggunakan Model Binomial

    Directory of Open Access Journals (Sweden)

    Mila Kurniawaty, Endah Rokhmati

    2011-05-01

    Full Text Available Option merupakan kontrak yang memberikan hak kepada pemiliknya untuk membeli (call option atau menjual (put option sejumlah aset dasar tertentu (underlying asset dengan harga tertentu (strike price dalam jangka waktu tertentu (sebelum atau saat expiration date. Perkembangan option belakangan ini memunculkan banyak model pricing untuk mengestimasi harga option, salah satu model yang digunakan adalah formula Black-Scholes. Multi-state option merupakan sebuah option yang payoff-nya didasarkan pada dua atau lebih aset dasar. Ada beberapa metode yang dapat digunakan dalam mengestimasi harga call option, salah satunya masyarakat finance sering menggunakan model binomial untuk estimasi berbagai model option yang lebih luas seperti multi-state call option. Selanjutnya, dari hasil estimasi call option dengan model binomial didapatkan formula terbaik berdasarkan penghitungan eror dengan mean square error. Dari penghitungan eror didapatkan eror rata-rata dari masing-masing formula pada model binomial. Hasil eror rata-rata menunjukkan bahwa estimasi menggunakan formula 5 titik lebih baik dari pada estimasi menggunakan formula 4 titik.

  14. Discrimination of numerical proportions: A comparison of binomial and Gaussian models.

    Science.gov (United States)

    Raidvee, Aire; Lember, Jüri; Allik, Jüri

    2017-01-01

    Observers discriminated the numerical proportion of two sets of elements (N = 9, 13, 33, and 65) that differed either by color or orientation. According to the standard Thurstonian approach, the accuracy of proportion discrimination is determined by irreducible noise in the nervous system that stochastically transforms the number of presented visual elements onto a continuum of psychological states representing numerosity. As an alternative to this customary approach, we propose a Thurstonian-binomial model, which assumes discrete perceptual states, each of which is associated with a certain visual element. It is shown that the probability β with which each visual element can be noticed and registered by the perceptual system can explain data of numerical proportion discrimination at least as well as the continuous Thurstonian-Gaussian model, and better, if the greater parsimony of the Thurstonian-binomial model is taken into account using AIC model selection. We conclude that Gaussian and binomial models represent two different fundamental principles-internal noise vs. using only a fraction of available information-which are both plausible descriptions of visual perception.

  15. Extra-binomial variation approach for analysis of pooled DNA sequencing data

    Science.gov (United States)

    Wallace, Chris

    2012-01-01

    Motivation: The invention of next-generation sequencing technology has made it possible to study the rare variants that are more likely to pinpoint causal disease genes. To make such experiments financially viable, DNA samples from several subjects are often pooled before sequencing. This induces large between-pool variation which, together with other sources of experimental error, creates over-dispersed data. Statistical analysis of pooled sequencing data needs to appropriately model this additional variance to avoid inflating the false-positive rate. Results: We propose a new statistical method based on an extra-binomial model to address the over-dispersion and apply it to pooled case-control data. We demonstrate that our model provides a better fit to the data than either a standard binomial model or a traditional extra-binomial model proposed by Williams and can analyse both rare and common variants with lower or more variable pool depths compared to the other methods. Availability: Package ‘extraBinomial’ is on http://cran.r-project.org/ Contact: chris.wallace@cimr.cam.ac.uk Supplementary information: Supplementary data are available at Bioinformatics Online. PMID:22976083

  16. Genome-enabled predictions for binomial traits in sugar beet populations.

    Science.gov (United States)

    Biscarini, Filippo; Stevanato, Piergiorgio; Broccanello, Chiara; Stella, Alessandra; Saccomani, Massimo

    2014-07-22

    Genomic information can be used to predict not only continuous but also categorical (e.g. binomial) traits. Several traits of interest in human medicine and agriculture present a discrete distribution of phenotypes (e.g. disease status). Root vigor in sugar beet (B. vulgaris) is an example of binomial trait of agronomic importance. In this paper, a panel of 192 SNPs (single nucleotide polymorphisms) was used to genotype 124 sugar beet individual plants from 18 lines, and to classify them as showing "high" or "low" root vigor. A threshold model was used to fit the relationship between binomial root vigor and SNP genotypes, through the matrix of genomic relationships between individuals in a genomic BLUP (G-BLUP) approach. From a 5-fold cross-validation scheme, 500 testing subsets were generated. The estimated average cross-validation error rate was 0.000731 (0.073%). Only 9 out of 12326 test observations (500 replicates for an average test set size of 24.65) were misclassified. The estimated prediction accuracy was quite high. Such accurate predictions may be related to the high estimated heritability for root vigor (0.783) and to the few genes with large effect underlying the trait. Despite the sparse SNP panel, there was sufficient within-scaffold LD where SNPs with large effect on root vigor were located to allow for genome-enabled predictions to work.

  17. Binomial and enumerative sampling of Tetranychus urticae (Acari: Tetranychidae) on peppermint in California.

    Science.gov (United States)

    Tollerup, Kris E; Marcum, Daniel; Wilson, Rob; Godfrey, Larry

    2013-08-01

    The two-spotted spider mite, Tetranychus urticae Koch, is an economic pest on peppermint [Mentha x piperita (L.), 'Black Mitcham'] grown in California. A sampling plan for T. urticae was developed under Pacific Northwest conditions in the early 1980s and has been used by California growers since approximately 1998. This sampling plan, however, is cumbersome and a poor predictor of T. urticae densities in California. Between June and August, the numbers of immature and adult T. urticae were counted on leaves at three commercial peppermint fields (sites) in 2010 and a single field in 2011. In each of seven locations per site, 45 leaves were sampled, that is, 9 leaves per five stems. Leaf samples were stratified by collecting three leaves from the top, middle, and bottom strata per stem. The on-plant distribution of T. urticae did not significantly differ among the stem strata through the growing season. Binomial and enumerative sampling plans were developed using generic Taylor's power law coefficient values. The best fit of our data for binomial sampling occurred using a tally threshold of T = 0. The optimum number of leaves required for T urticae at the critical density of five mites per leaf was 20 for the binomial and 23 for the enumerative sampling plans, respectively. Sampling models were validated using Resampling for Validation of Sampling Plan Software.

  18. Partitioning detectability components in populations subject to within-season temporary emigration using binomial mixture models.

    Science.gov (United States)

    O'Donnell, Katherine M; Thompson, Frank R; Semlitsch, Raymond D

    2015-01-01

    Detectability of individual animals is highly variable and nearly always binomial mixture models to account for multiple sources of variation in detectability. The state process of the hierarchical model describes ecological mechanisms that generate spatial and temporal patterns in abundance, while the observation model accounts for the imperfect nature of counting individuals due to temporary emigration and false absences. We illustrate our model's potential advantages, including the allowance of temporary emigration between sampling periods, with a case study of southern red-backed salamanders Plethodon serratus. We fit our model and a standard binomial mixture model to counts of terrestrial salamanders surveyed at 40 sites during 3-5 surveys each spring and fall 2010-2012. Our models generated similar parameter estimates to standard binomial mixture models. Aspect was the best predictor of salamander abundance in our case study; abundance increased as aspect became more northeasterly. Increased time-since-rainfall strongly decreased salamander surface activity (i.e. availability for sampling), while higher amounts of woody cover objects and rocks increased conditional detection probability (i.e. probability of capture, given an animal is exposed to sampling). By explicitly accounting for both components of detectability, we increased congruence between our statistical modeling and our ecological understanding of the system. We stress the importance of choosing survey locations and protocols that maximize species availability and conditional detection probability to increase population parameter estimate reliability.

  19. Analysis of railroad tank car releases using a generalized binomial model.

    Science.gov (United States)

    Liu, Xiang; Hong, Yili

    2015-11-01

    The United States is experiencing an unprecedented boom in shale oil production, leading to a dramatic growth in petroleum crude oil traffic by rail. In 2014, U.S. railroads carried over 500,000 tank carloads of petroleum crude oil, up from 9500 in 2008 (a 5300% increase). In light of continual growth in crude oil by rail, there is an urgent national need to manage this emerging risk. This need has been underscored in the wake of several recent crude oil release incidents. In contrast to highway transport, which usually involves a tank trailer, a crude oil train can carry a large number of tank cars, having the potential for a large, multiple-tank-car release incident. Previous studies exclusively assumed that railroad tank car releases in the same train accident are mutually independent, thereby estimating the number of tank cars releasing given the total number of tank cars derailed based on a binomial model. This paper specifically accounts for dependent tank car releases within a train accident. We estimate the number of tank cars releasing given the number of tank cars derailed based on a generalized binomial model. The generalized binomial model provides a significantly better description for the empirical tank car accident data through our numerical case study. This research aims to provide a new methodology and new insights regarding the further development of risk management strategies for improving railroad crude oil transportation safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Meta-analysis for diagnostic accuracy studies: a new statistical model using beta-binomial distributions and bivariate copulas.

    Science.gov (United States)

    Kuss, Oliver; Hoyer, Annika; Solms, Alexander

    2014-01-15

    There are still challenges when meta-analyzing data from studies on diagnostic accuracy. This is mainly due to the bivariate nature of the response where information on sensitivity and specificity must be summarized while accounting for their correlation within a single trial. In this paper, we propose a new statistical model for the meta-analysis for diagnostic accuracy studies. This model uses beta-binomial distributions for the marginal numbers of true positives and true negatives and links these margins by a bivariate copula distribution. The new model comes with all the features of the current standard model, a bivariate logistic regression model with random effects, but has the additional advantages of a closed likelihood function and a larger flexibility for the correlation structure of sensitivity and specificity. In a simulation study, which compares three copula models and two implementations of the standard model, the Plackett and the Gauss copula do rarely perform worse but frequently better than the standard model. We use an example from a meta-analysis to judge the diagnostic accuracy of telomerase (a urinary tumor marker) for the diagnosis of primary bladder cancer for illustration. Copyright © 2013 John Wiley & Sons, Ltd.

  1. A Record Holder Female Athlete’s Train ing Loads and its Distribution in Women 400 meter Hurdle Running

    Directory of Open Access Journals (Sweden)

    Sibel DÜNDAR

    2015-07-01

    Full Text Available The purpose of this study was to investigate the effects on 400 mt characteristics of women training load used in the hurdle runnig , the distribution and performance according to the period. At this study female athlete’s, who won second place at the European Champion Clubs' Cup Competitions and had a record - breaking six times in a country, five - year training loads and degrees were investigated. In this study, athlete’s degrees an d training loads were analyzed between the years of 1982 - 1987. Atlete’s best 100m,200m,400m,400m hurdle degrees and some training loads (sprint, andurance, weight lifting were assessed by the means and satandart deviations. Athlete’s sprint and training l oads mean and standard deviation values were calculated as 100 m ( 11.96 ± 0.17 , 200m ( 25.0 ± 0.38 , 400m ( 56.07 ± 0.91 and 400 m hurdle running ( 60.38 ± 1.88 and for the training loads of 0 - 150 m sprint ( 66.85 ± 18.95 m, endurance ( 2 02.55 ± 57.56 miles and weightlifting( 151.88 ± 68.2 tons. It was observed that percentage of change of the value of training loads and the running performance changes were not increase at the same rate. Regarding the relationship between the best run ning degree and training load, it was found a significant relationship between only 60 m sprint and 150 - 450 m sprint degrees.

  2. Negative ... concord?

    NARCIS (Netherlands)

    Giannakidou, A

    The main claim of this paper is that a general theory of negative concord (NC) should allow for the possibility of NC involving scoping of a universal quantifier above negation. I propose that Greek NC instantiates this option. Greek n-words will be analyzed as polarity sensitive universal

  3. Jump-and-return sandwiches: A new family of binomial-like selective inversion sequences with improved performance

    Science.gov (United States)

    Brenner, Tom; Chen, Johnny; Stait-Gardner, Tim; Zheng, Gang; Matsukawa, Shingo; Price, William S.

    2018-03-01

    A new family of binomial-like inversion sequences, named jump-and-return sandwiches (JRS), has been developed by inserting a binomial-like sequence into a standard jump-and-return sequence, discovered through use of a stochastic Genetic Algorithm optimisation. Compared to currently used binomial-like inversion sequences (e.g., 3-9-19 and W5), the new sequences afford wider inversion bands and narrower non-inversion bands with an equal number of pulses. As an example, two jump-and-return sandwich 10-pulse sequences achieved 95% inversion at offsets corresponding to 9.4% and 10.3% of the non-inversion band spacing, compared to 14.7% for the binomial-like W5 inversion sequence, i.e., they afforded non-inversion bands about two thirds the width of the W5 non-inversion band.

  4. Feedback from the European Bioanalysis Forum: focus workshop on current analysis of immunogenicity: best practices and regulatory hurdles.

    Science.gov (United States)

    Goodman, Joanne; Cowen, Simon; Devanarayan, Viswanath; Egging, David; Emrich, Thomas; Golob, Michaela; Kramer, Daniel; McNally, Jim; Munday, James; Nelson, Robert; Pedras-Vasconcelos, João A; Piironen, Timo; Sickert, Denise; Skibeli, Venke; Fjording, Marianne Scheel; Timmerman, Philip

    2018-02-01

    European Bioanalysis Forum Workshop, Lisbon, Portugal, September 2016: At the recent European Bioanalysis Forum Focus Workshop, 'current analysis of immunogenicity: best practices and regulatory hurdles', several important challenges facing the bioanalytical community in relation to immunogenicity assays were discussed through a mixture of presentations and panel sessions. The main areas of focus were the evolving regulatory landscape, challenges of assay interferences from either drug or target, cut-point setting and whether alternative assays can be used to replace neutralizing antibody assays. This workshop report captures discussions and potential solutions and/or recommendations made by the speakers and delegates.

  5. The impact of social grant dependency on smallholder maize producers’ market participation in South Africa: Application of the double-hurdle model

    Directory of Open Access Journals (Sweden)

    Sikhulumile Sinyolo

    2017-05-01

    Full Text Available Background: Social grants have become an increasingly popular means of improving the welfare of poor households in South Africa and beyond. While the goals of these transfers are to alleviate current poverty as well as to improve human capital capacity, they also have unintended effects, positive or negative, on beneficiary households. A question that has not been adequately addressed in the literature is the role that social grants play in the efforts to commercialise smallholder farming. Aim: The aim of this study was to examine the impact of social grant dependency on the incentives of smallholder maize producers to participate in the market. Setting: The study was done in the rural areas of four districts (Harry Gwala, Umzinyathi, Umkhanyakude and Uthukela in the KwaZulu-Natal province, South Africa. Methods: The study adopted a quantitative research design. A total of 984 households were randomly selected from the four districts, of which 774 had planted maize in the previous season. The analysis was done on the 774 farmers who had planted maize. The double-hurdle model was used for statistical analysis. Results: The results show a negative association between social grant dependency and market participation, suggesting that social grant-dependent households are more subsistent, producing less marketable surplus. Moreover, households with access to social grants sold less quantities of maize in the market, indicating reduced selling incentives. Conclusion: The study indicates that social grants reduce the incentives of smallholder farmers to commercialise their production activities. The results suggest that, while policies aimed at reducing transaction costs would increase smallholder market participation, attention should be paid on how to reduce social grants’ dis-incentive effects. To reduce spill over effects to unintended household members, the study recommends offering part of the grant as ‘in-kind support’, which is

  6. Planning Training Loads for the 400 M Hurdles in Three-Month Mesocycles using Artificial Neural Networks.

    Science.gov (United States)

    Przednowek, Krzysztof; Iskra, Janusz; Wiktorowicz, Krzysztof; Krzeszowski, Tomasz; Maszczyk, Adam

    2017-12-01

    This paper presents a novel approach to planning training loads in hurdling using artificial neural networks. The neural models performed the task of generating loads for athletes' training for the 400 meters hurdles. All the models were calculated based on the training data of 21 Polish National Team hurdlers, aged 22.25 ± 1.96, competing between 1989 and 2012. The analysis included 144 training plans that represented different stages in the annual training cycle. The main contribution of this paper is to develop neural models for planning training loads for the entire career of a typical hurdler. In the models, 29 variables were used, where four characterized the runner and 25 described the training process. Two artificial neural networks were used: a multi-layer perceptron and a network with radial basis functions. To assess the quality of the models, the leave-one-out cross-validation method was used in which the Normalized Root Mean Squared Error was calculated. The analysis shows that the method generating the smallest error was the radial basis function network with nine neurons in the hidden layer. Most of the calculated training loads demonstrated a non-linear relationship across the entire competitive period. The resulting model can be used as a tool to assist a coach in planning training loads during a selected training period.

  7. Clearing up the hazy road from bench to bedside: A framework for integrating the fourth hurdle into translational medicine

    Directory of Open Access Journals (Sweden)

    John Jürgen H

    2008-09-01

    Full Text Available Abstract Background New products evolving from research and development can only be translated to medical practice on a large scale if they are reimbursed by third-party payers. Yet the decision processes regarding reimbursement are highly complex and internationally heterogeneous. This study develops a process-oriented framework for monitoring these so-called fourth hurdle procedures in the context of product development from bench to bedside. The framework is suitable both for new drugs and other medical technologies. Methods The study is based on expert interviews and literature searches, as well as an analysis of 47 websites of coverage decision-makers in England, Germany and the USA. Results Eight key steps for monitoring fourth hurdle procedures from a company perspective were determined: entering the scope of a healthcare payer; trigger of decision process; assessment; appraisal; setting level of reimbursement; establishing rules for service provision; formal and informal participation; and publication of the decision and supplementary information. Details are given for the English National Institute for Health and Clinical Excellence, the German Federal Joint Committee, Medicare's National and Local Coverage Determinations, and for Blue Cross Blue Shield companies. Conclusion Coverage determination decisions for new procedures tend to be less formalized than for novel drugs. The analysis of coverage procedures and requirements shows that the proof of patient benefit is essential. Cost-effectiveness is likely to gain importance in future.

  8. Beta-binomial model for meta-analysis of odds ratios.

    Science.gov (United States)

    Bakbergenuly, Ilyas; Kulinskaya, Elena

    2017-05-20

    In meta-analysis of odds ratios (ORs), heterogeneity between the studies is usually modelled via the additive random effects model (REM). An alternative, multiplicative REM for ORs uses overdispersion. The multiplicative factor in this overdispersion model (ODM) can be interpreted as an intra-class correlation (ICC) parameter. This model naturally arises when the probabilities of an event in one or both arms of a comparative study are themselves beta-distributed, resulting in beta-binomial distributions. We propose two new estimators of the ICC for meta-analysis in this setting. One is based on the inverted Breslow-Day test, and the other on the improved gamma approximation by Kulinskaya and Dollinger (2015, p. 26) to the distribution of Cochran's Q. The performance of these and several other estimators of ICC on bias and coverage is studied by simulation. Additionally, the Mantel-Haenszel approach to estimation of ORs is extended to the beta-binomial model, and we study performance of various ICC estimators when used in the Mantel-Haenszel or the inverse-variance method to combine ORs in meta-analysis. The results of the simulations show that the improved gamma-based estimator of ICC is superior for small sample sizes, and the Breslow-Day-based estimator is the best for n⩾100. The Mantel-Haenszel-based estimator of OR is very biased and is not recommended. The inverse-variance approach is also somewhat biased for ORs≠1, but this bias is not very large in practical settings. Developed methods and R programs, provided in the Web Appendix, make the beta-binomial model a feasible alternative to the standard REM for meta-analysis of ORs. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  9. Metaprop: a Stata command to perform meta-analysis of binomial data.

    Science.gov (United States)

    Nyaga, Victoria N; Arbyn, Marc; Aerts, Marc

    2014-01-01

    Meta-analyses have become an essential tool in synthesizing evidence on clinical and epidemiological questions derived from a multitude of similar studies assessing the particular issue. Appropriate and accessible statistical software is needed to produce the summary statistic of interest. Metaprop is a statistical program implemented to perform meta-analyses of proportions in Stata. It builds further on the existing Stata procedure metan which is typically used to pool effects (risk ratios, odds ratios, differences of risks or means) but which is also used to pool proportions. Metaprop implements procedures which are specific to binomial data and allows computation of exact binomial and score test-based confidence intervals. It provides appropriate methods for dealing with proportions close to or at the margins where the normal approximation procedures often break down, by use of the binomial distribution to model the within-study variability or by allowing Freeman-Tukey double arcsine transformation to stabilize the variances. Metaprop was applied on two published meta-analyses: 1) prevalence of HPV-infection in women with a Pap smear showing ASC-US; 2) cure rate after treatment for cervical precancer using cold coagulation. The first meta-analysis showed a pooled HPV-prevalence of 43% (95% CI: 38%-48%). In the second meta-analysis, the pooled percentage of cured women was 94% (95% CI: 86%-97%). By using metaprop, no studies with 0% or 100% proportions were excluded from the meta-analysis. Furthermore, study specific and pooled confidence intervals always were within admissible values, contrary to the original publication, where metan was used.

  10. A comparison of methods for the analysis of binomial clustered outcomes in behavioral research.

    Science.gov (United States)

    Ferrari, Alberto; Comelli, Mario

    2016-12-01

    In behavioral research, data consisting of a per-subject proportion of "successes" and "failures" over a finite number of trials often arise. This clustered binary data are usually non-normally distributed, which can distort inference if the usual general linear model is applied and sample size is small. A number of more advanced methods is available, but they are often technically challenging and a comparative assessment of their performances in behavioral setups has not been performed. We studied the performances of some methods applicable to the analysis of proportions; namely linear regression, Poisson regression, beta-binomial regression and Generalized Linear Mixed Models (GLMMs). We report on a simulation study evaluating power and Type I error rate of these models in hypothetical scenarios met by behavioral researchers; plus, we describe results from the application of these methods on data from real experiments. Our results show that, while GLMMs are powerful instruments for the analysis of clustered binary outcomes, beta-binomial regression can outperform them in a range of scenarios. Linear regression gave results consistent with the nominal level of significance, but was overall less powerful. Poisson regression, instead, mostly led to anticonservative inference. GLMMs and beta-binomial regression are generally more powerful than linear regression; yet linear regression is robust to model misspecification in some conditions, whereas Poisson regression suffers heavily from violations of the assumptions when used to model proportion data. We conclude providing directions to behavioral scientists dealing with clustered binary data and small sample sizes. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Binomial tree method for pricing a regime-switching volatility stock loans

    Science.gov (United States)

    Putri, Endah R. M.; Zamani, Muhammad S.; Utomo, Daryono B.

    2018-03-01

    Binomial model with regime switching may represents the price of stock loan which follows the stochastic process. Stock loan is one of alternative that appeal investors to get the liquidity without selling the stock. The stock loan mechanism resembles that of American call option when someone can exercise any time during the contract period. From the resembles both of mechanism, determination price of stock loan can be interpreted from the model of American call option. The simulation result shows the behavior of the price of stock loan under a regime-switching with respect to various interest rate and maturity.

  12. CUANDO FALLA EL SUPUESTO DE HOMOCEDASTICIDAD EN VARIABLES CON DISTRIBUCIÓN BINOMIAL

    OpenAIRE

    Edison Ramiro Vásquez; Alberto Caballero Núñez

    2011-01-01

    Se utilizó el proceso de Simulación de Monte Carlopara generar poblaciones de variables aleatorias con distribuciónBinomial con varianzas homogéneas y heterogéneas; para cinco,10 y 30 observaciones por unidad experimental (n) y probabi-lidad de éxito del evento de 0,10, 0,20, ¿,0,90(p). Se conformaronexperimentos en Diseño Bloques al Azar con tres, cinco y nuevetratamientos (t); cuatro y ocho réplicas(r); para cada combinaciónt-r-n, se generaron 100 experimentos. A modo de disponer deun refer...

  13. Constructing Binomial Trees Via Random Maps for Analysis of Financial Assets

    Directory of Open Access Journals (Sweden)

    Antonio Airton Carneiro de Freitas

    2010-04-01

    Full Text Available Random maps can be constructed from a priori knowledge of the financial assets. It is also addressed the reverse problem, i.e. from a function of an empirical stationary probability density function we set up a random map that naturally leads to an implied binomial tree, allowing the adjustment of models, including the ability to incorporate jumps. An applica- tion related to the options market is presented. It is emphasized that the quality of the model to incorporate a priori knowledge of the financial asset may be affected, for example, by the skewed vision of the analyst.

  14. proportion: A comprehensive R package for inference on single Binomial proportion and Bayesian computations

    Directory of Open Access Journals (Sweden)

    M. Subbiah

    2017-01-01

    Full Text Available Extensive statistical practice has shown the importance and relevance of the inferential problem of estimating probability parameters in a binomial experiment; especially on the issues of competing intervals from frequentist, Bayesian, and Bootstrap approaches. The package written in the free R environment and presented in this paper tries to take care of the issues just highlighted, by pooling a number of widely available and well-performing methods and apporting on them essential variations. A wide range of functions helps users with differing skills to estimate, evaluate, summarize, numerically and graphically, various measures adopting either the frequentist or the Bayesian paradigm.

  15. Detection of progression of glaucomatous visual field damage using the point-wise method with the binomial test.

    Science.gov (United States)

    Karakawa, Ayako; Murata, Hiroshi; Hirasawa, Hiroyo; Mayama, Chihiro; Asaoka, Ryo

    2013-01-01

    To compare the performance of newly proposed point-wise linear regression (PLR) with the binomial test (binomial PLR) against mean deviation (MD) trend analysis and permutation analyses of PLR (PoPLR), in detecting global visual field (VF) progression in glaucoma. 15 VFs (Humphrey Field Analyzer, SITA standard, 24-2) were collected from 96 eyes of 59 open angle glaucoma patients (6.0 ± 1.5 [mean ± standard deviation] years). Using the total deviation of each point on the 2(nd) to 16(th) VFs (VF2-16), linear regression analysis was carried out. The numbers of VF test points with a significant trend at various probability levels (pbinomial test (one-side). A VF series was defined as "significant" if the median p-value from the binomial test was binomial PLR method (0.14 to 0.86) was significantly higher than MD trend analysis (0.04 to 0.89) and PoPLR (0.09 to 0.93). The PIS of the proposed method (0.0 to 0.17) was significantly lower than the MD approach (0.0 to 0.67) and PoPLR (0.07 to 0.33). The PBNS of the three approaches were not significantly different. The binomial BLR method gives more consistent results than MD trend analysis and PoPLR, hence it will be helpful as a tool to 'flag' possible VF deterioration.

  16. Properties of parameter estimation techniques for a beta-binomial failure model. Final technical report

    International Nuclear Information System (INIS)

    Shultis, J.K.; Buranapan, W.; Eckhoff, N.D.

    1981-12-01

    Of considerable importance in the safety analysis of nuclear power plants are methods to estimate the probability of failure-on-demand, p, of a plant component that normally is inactive and that may fail when activated or stressed. Properties of five methods for estimating from failure-on-demand data the parameters of the beta prior distribution in a compound beta-binomial probability model are examined. Simulated failure data generated from a known beta-binomial marginal distribution are used to estimate values of the beta parameters by (1) matching moments of the prior distribution to those of the data, (2) the maximum likelihood method based on the prior distribution, (3) a weighted marginal matching moments method, (4) an unweighted marginal matching moments method, and (5) the maximum likelihood method based on the marginal distribution. For small sample sizes (N = or < 10) with data typical of low failure probability components, it was found that the simple prior matching moments method is often superior (e.g. smallest bias and mean squared error) while for larger sample sizes the marginal maximum likelihood estimators appear to be best

  17. Estimation of component failure probability from masked binomial system testing data

    International Nuclear Information System (INIS)

    Tan Zhibin

    2005-01-01

    The component failure probability estimates from analysis of binomial system testing data are very useful because they reflect the operational failure probability of components in the field which is similar to the test environment. In practice, this type of analysis is often confounded by the problem of data masking: the status of tested components is unknown. Methods in considering this type of uncertainty are usually computationally intensive and not practical to solve the problem for complex systems. In this paper, we consider masked binomial system testing data and develop a probabilistic model to efficiently estimate component failure probabilities. In the model, all system tests are classified into test categories based on component coverage. Component coverage of test categories is modeled by a bipartite graph. Test category failure probabilities conditional on the status of covered components are defined. An EM algorithm to estimate component failure probabilities is developed based on a simple but powerful concept: equivalent failures and tests. By simulation we not only demonstrate the convergence and accuracy of the algorithm but also show that the probabilistic model is capable of analyzing systems in series, parallel and any other user defined structures. A case study illustrates an application in test case prioritization

  18. Modeling random telegraph signal noise in CMOS image sensor under low light based on binomial distribution

    International Nuclear Information System (INIS)

    Zhang Yu; Wang Guangyi; Lu Xinmiao; Hu Yongcai; Xu Jiangtao

    2016-01-01

    The random telegraph signal noise in the pixel source follower MOSFET is the principle component of the noise in the CMOS image sensor under low light. In this paper, the physical and statistical model of the random telegraph signal noise in the pixel source follower based on the binomial distribution is set up. The number of electrons captured or released by the oxide traps in the unit time is described as the random variables which obey the binomial distribution. As a result, the output states and the corresponding probabilities of the first and the second samples of the correlated double sampling circuit are acquired. The standard deviation of the output states after the correlated double sampling circuit can be obtained accordingly. In the simulation section, one hundred thousand samples of the source follower MOSFET have been simulated, and the simulation results show that the proposed model has the similar statistical characteristics with the existing models under the effect of the channel length and the density of the oxide trap. Moreover, the noise histogram of the proposed model has been evaluated at different environmental temperatures. (paper)

  19. Is ‘hit and run’ a single word? The processing of irreversible binomials in neglect dyslexia

    Directory of Open Access Journals (Sweden)

    Giorgio eArcara

    2012-02-01

    Full Text Available The present study is the first neuropsychological investigation into the problem of the mental representation and processing of irreversible binomials, i.e. word pairs linked by a conjunction (e.g. ‘hit and run’, ‘dead or alive’. In order to test their lexical status, the phenomenon of neglect dyslexia is explored.People with left-sided neglect dyslexia show a clear lexical effect: they can read irreversible binomials better (i.e., by dropping the leftmost words less frequently when their components are presented in their correct order. This may be taken as an indication that they treat these constructions as lexical, not decomposable, elements. This finding therefore constitutes strong evidence that irreversible binomials tend to be stored in the mental lexicon as a whole and that this whole form is preferably addressed in the retrieval process.

  20. Assessing the Option to Abandon an Investment Project by the Binomial Options Pricing Model

    Directory of Open Access Journals (Sweden)

    Salvador Cruz Rambaud

    2016-01-01

    Full Text Available Usually, traditional methods for investment project appraisal such as the net present value (hereinafter NPV do not incorporate in their values the operational flexibility offered by including a real option included in the project. In this paper, real options, and more specifically the option to abandon, are analysed as a complement to cash flow sequence which quantifies the project. In this way, by considering the existing analogy with financial options, a mathematical expression is derived by using the binomial options pricing model. This methodology provides the value of the option to abandon the project within one, two, and in general n periods. Therefore, this paper aims to be a useful tool in determining the value of the option to abandon according to its residual value, thus making easier the control of the uncertainty element within the project.

  1. Is "hit and run" a single word? The processing of irreversible binomials in neglect dyslexia.

    Science.gov (United States)

    Arcara, Giorgio; Lacaita, Graziano; Mattaloni, Elisa; Passarini, Laura; Mondini, Sara; Benincà, Paola; Semenza, Carlo

    2012-01-01

    The present study is the first neuropsychological investigation into the problem of the mental representation and processing of irreversible binomials (IBs), i.e., word pairs linked by a conjunction (e.g., "hit and run," "dead or alive"). In order to test their lexical status, the phenomenon of neglect dyslexia is explored. People with left-sided neglect dyslexia show a clear lexical effect: they can read IBs better (i.e., by dropping the leftmost words less frequently) when their components are presented in their correct order. This may be taken as an indication that they treat these constructions as lexical, not decomposable, elements. This finding therefore constitutes strong evidence that IBs tend to be stored in the mental lexicon as a whole and that this whole form is preferably addressed in the retrieval process.

  2. Binomial moments of the distance distribution and the probability of undetected error

    Energy Technology Data Exchange (ETDEWEB)

    Barg, A. [Lucent Technologies, Murray Hill, NJ (United States). Bell Labs.; Ashikhmin, A. [Los Alamos National Lab., NM (United States)

    1998-09-01

    In [1] K.A.S. Abdel-Ghaffar derives a lower bound on the probability of undetected error for unrestricted codes. The proof relies implicitly on the binomial moments of the distance distribution of the code. The authors use the fact that these moments count the size of subcodes of the code to give a very simple proof of the bound in [1] by showing that it is essentially equivalent to the Singleton bound. They discuss some combinatorial connections revealed by this proof. They also discuss some improvements of this bound. Finally, they analyze asymptotics. They show that an upper bound on the undetected error exponent that corresponds to the bound of [1] improves known bounds on this function.

  3. The multi-class binomial failure rate model for the treatment of common-cause failures

    International Nuclear Information System (INIS)

    Hauptmanns, U.

    1995-01-01

    The impact of common cause failures (CCF) on PSA results for NPPs is in sharp contrast with the limited quality which can be achieved in their assessment. This is due to the dearth of observations and cannot be remedied in the short run. Therefore the methods employed for calculating failure rates should be devised such as to make the best use of the few available observations on CCF. The Multi-Class Binomial Failure Rate (MCBFR) Model achieves this by assigning observed failures to different classes according to their technical characteristics and applying the BFR formalism to each of these. The results are hence determined by a superposition of BFR type expressions for each class, each of them with its own coupling factor. The model thus obtained flexibly reproduces the dependence of CCF rates on failure multiplicity insinuated by the observed failure multiplicities. This is demonstrated by evaluating CCFs observed for combined impulse pilot valves in German NPPs. (orig.) [de

  4. Analytic degree distributions of horizontal visibility graphs mapped from unrelated random series and multifractal binomial measures

    Science.gov (United States)

    Xie, Wen-Jie; Han, Rui-Qi; Jiang, Zhi-Qiang; Wei, Lijian; Zhou, Wei-Xing

    2017-08-01

    Complex network is not only a powerful tool for the analysis of complex system, but also a promising way to analyze time series. The algorithm of horizontal visibility graph (HVG) maps time series into graphs, whose degree distributions are numerically and analytically investigated for certain time series. We derive the degree distributions of HVGs through an iterative construction process of HVGs. The degree distributions of the HVG and the directed HVG for random series are derived to be exponential, which confirms the analytical results from other methods. We also obtained the analytical expressions of degree distributions of HVGs and in-degree and out-degree distributions of directed HVGs transformed from multifractal binomial measures, which agree excellently with numerical simulations.

  5. The Compound Binomial Risk Model with Randomly Charging Premiums and Paying Dividends to Shareholders

    Directory of Open Access Journals (Sweden)

    Xiong Wang

    2013-01-01

    Full Text Available Based on characteristics of the nonlife joint-stock insurance company, this paper presents a compound binomial risk model that randomizes the premium income on unit time and sets the threshold for paying dividends to shareholders. In this model, the insurance company obtains the insurance policy in unit time with probability and pays dividends to shareholders with probability when the surplus is no less than . We then derive the recursive formulas of the expected discounted penalty function and the asymptotic estimate for it. And we will derive the recursive formulas and asymptotic estimates for the ruin probability and the distribution function of the deficit at ruin. The numerical examples have been shown to illustrate the accuracy of the asymptotic estimations.

  6. Connecting Binomial and Black-Scholes Option Pricing Models: A Spreadsheet-Based Illustration

    Directory of Open Access Journals (Sweden)

    Yi Feng

    2012-07-01

    Full Text Available The Black-Scholes option pricing model is part of the modern financial curriculum, even at the introductory level. However, as the derivation of the model, which requires advanced mathematical tools, is well beyond the scope of standard finance textbooks, the model has remained a great, but mysterious, recipe for many students. This paper illustrates, from a pedagogic perspective, how a simple binomial model, which converges to the Black-Scholes formula, can capture the economic insight in the original derivation. Microsoft ExcelTM plays an important pedagogic role in connecting the two models. The interactivity as provided by scroll bars, in conjunction with Excel's graphical features, will allow students to visualize the impacts of individual input parameters on option pricing.

  7. Organ procurement and the body donor-family binomial: instruments to subsidize nursing approach

    Directory of Open Access Journals (Sweden)

    Gisele da Cruz Ferreira

    2013-05-01

    Full Text Available We aimed to describe the design of instruments to subsidize the care for the body donor-family binomial in the perspective of the process of organ procurement. The Activities of Living Model grounded the instruments for data collection. We identified 33 possible diagnoses, 14 associated to the body preservation and 19 to responses from family members facing grieving and the decision on whether to authorize the donation. We selected 31 interventions to preserve the body for organs/tissues procurement, and 25 to meet the needs for information, coping and support for the family decision. The nursing diagnoses, interventions, and outcomes were registered according to the North American Nursing Diagnosis Association, Nursing Intervention Classification, and Nursing Outcome Classification, respectively. The instruments follow the legislation of the Board of Nursing and the donor/organ procurement, needing to be validated by field experts.

  8. A comparison of LMC and SDL complexity measures on binomial distributions

    Science.gov (United States)

    Piqueira, José Roberto C.

    2016-02-01

    The concept of complexity has been widely discussed in the last forty years, with a lot of thinking contributions coming from all areas of the human knowledge, including Philosophy, Linguistics, History, Biology, Physics, Chemistry and many others, with mathematicians trying to give a rigorous view of it. In this sense, thermodynamics meets information theory and, by using the entropy definition, López-Ruiz, Mancini and Calbet proposed a definition for complexity that is referred as LMC measure. Shiner, Davison and Landsberg, by slightly changing the LMC definition, proposed the SDL measure and the both, LMC and SDL, are satisfactory to measure complexity for a lot of problems. Here, SDL and LMC measures are applied to the case of a binomial probability distribution, trying to clarify how the length of the data set implies complexity and how the success probability of the repeated trials determines how complex the whole set is.

  9. Rgbp: An R Package for Gaussian, Poisson, and Binomial Random Effects Models with Frequency Coverage Evaluations

    Directory of Open Access Journals (Sweden)

    Hyungsuk Tak

    2017-06-01

    Full Text Available Rgbp is an R package that provides estimates and verifiable confidence intervals for random effects in two-level conjugate hierarchical models for overdispersed Gaussian, Poisson, and binomial data. Rgbp models aggregate data from k independent groups summarized by observed sufficient statistics for each random effect, such as sample means, possibly with covariates. Rgbp uses approximate Bayesian machinery with unique improper priors for the hyper-parameters, which leads to good repeated sampling coverage properties for random effects. A special feature of Rgbp is an option that generates synthetic data sets to check whether the interval estimates for random effects actually meet the nominal confidence levels. Additionally, Rgbp provides inference statistics for the hyper-parameters, e.g., regression coefficients.

  10. A Flexible, Efficient Binomial Mixed Model for Identifying Differential DNA Methylation in Bisulfite Sequencing Data

    Science.gov (United States)

    Lea, Amanda J.

    2015-01-01

    Identifying sources of variation in DNA methylation levels is important for understanding gene regulation. Recently, bisulfite sequencing has become a popular tool for investigating DNA methylation levels. However, modeling bisulfite sequencing data is complicated by dramatic variation in coverage across sites and individual samples, and because of the computational challenges of controlling for genetic covariance in count data. To address these challenges, we present a binomial mixed model and an efficient, sampling-based algorithm (MACAU: Mixed model association for count data via data augmentation) for approximate parameter estimation and p-value computation. This framework allows us to simultaneously account for both the over-dispersed, count-based nature of bisulfite sequencing data, as well as genetic relatedness among individuals. Using simulations and two real data sets (whole genome bisulfite sequencing (WGBS) data from Arabidopsis thaliana and reduced representation bisulfite sequencing (RRBS) data from baboons), we show that our method provides well-calibrated test statistics in the presence of population structure. Further, it improves power to detect differentially methylated sites: in the RRBS data set, MACAU detected 1.6-fold more age-associated CpG sites than a beta-binomial model (the next best approach). Changes in these sites are consistent with known age-related shifts in DNA methylation levels, and are enriched near genes that are differentially expressed with age in the same population. Taken together, our results indicate that MACAU is an efficient, effective tool for analyzing bisulfite sequencing data, with particular salience to analyses of structured populations. MACAU is freely available at www.xzlab.org/software.html. PMID:26599596

  11. Semiparametric Allelic Tests for Mapping Multiple Phenotypes: Binomial Regression and Mahalanobis Distance.

    Science.gov (United States)

    Majumdar, Arunabha; Witte, John S; Ghosh, Saurabh

    2015-12-01

    Binary phenotypes commonly arise due to multiple underlying quantitative precursors and genetic variants may impact multiple traits in a pleiotropic manner. Hence, simultaneously analyzing such correlated traits may be more powerful than analyzing individual traits. Various genotype-level methods, e.g., MultiPhen (O'Reilly et al. []), have been developed to identify genetic factors underlying a multivariate phenotype. For univariate phenotypes, the usefulness and applicability of allele-level tests have been investigated. The test of allele frequency difference among cases and controls is commonly used for mapping case-control association. However, allelic methods for multivariate association mapping have not been studied much. In this article, we explore two allelic tests of multivariate association: one using a Binomial regression model based on inverted regression of genotype on phenotype (Binomial regression-based Association of Multivariate Phenotypes [BAMP]), and the other employing the Mahalanobis distance between two sample means of the multivariate phenotype vector for two alleles at a single-nucleotide polymorphism (Distance-based Association of Multivariate Phenotypes [DAMP]). These methods can incorporate both discrete and continuous phenotypes. Some theoretical properties for BAMP are studied. Using simulations, the power of the methods for detecting multivariate association is compared with the genotype-level test MultiPhen's. The allelic tests yield marginally higher power than MultiPhen for multivariate phenotypes. For one/two binary traits under recessive mode of inheritance, allelic tests are found to be substantially more powerful. All three tests are applied to two different real data and the results offer some support for the simulation study. We propose a hybrid approach for testing multivariate association that implements MultiPhen when Hardy-Weinberg Equilibrium (HWE) is violated and BAMP otherwise, because the allelic approaches assume HWE

  12. Hurdles in tissue engineering/regenerative medicine product commercialization: a pilot survey of governmental funding agencies and the financial industry.

    Science.gov (United States)

    Bertram, Timothy A; Tentoff, Edward; Johnson, Peter C; Tawil, Bill; Van Dyke, Mark; Hellman, Kiki B

    2012-11-01

    The Tissue Engineering and Regenerative Medicine International Society of the Americas (TERMIS-AM) Industry Committee conducted a semiquantitative opinion survey in 2010 to delineate potential hurdles to commercialization perceived by the TERMIS constituency groups that participate in the stream of technology commercialization (academia, start-up companies, development-stage companies, and established companies). A significant hurdle identified consistently by each group was access to capital for advancing potential technologies into development pathways leading to commercialization. A follow-on survey was developed by the TERMIS-AM Industry Committee to evaluate the financial industry's perspectives on investing in regenerative medical technologies. The survey, composed of 15 questions, was developed and provided to 37 investment organizations in one of three sectors (governmental, private, and public investors). The survey was anonymous and confidential with sector designation the only identifying feature of each respondent's organization. Approximately 80% of the survey was composed of respondents from the public (n=14) and private (n=15) sectors. Each respondent represents one investment organization with the potential of multiple participants participating to form the organization's response. The remaining organizations represented governmental agencies (n=8). Results from this survey indicate that a high percentage ($2MM into regenerative medical companies at the different stages of a company's life cycle. Investors recognized major hurdles to this emerging industry, including regulatory pathway, clinical translation, and reimbursement of these new products. Investments in regenerative technologies have been cyclical over the past 10-15 years, but investors recognized a 1-5-year investment period before the exit via Merger and Acquisition (M&A). Investors considered musculoskeletal products and their top technology choice with companies in the clinical stage

  13. Patterns of medicinal plant use: an examination of the Ecuadorian Shuar medicinal flora using contingency table and binomial analyses.

    Science.gov (United States)

    Bennett, Bradley C; Husby, Chad E

    2008-03-28

    Botanical pharmacopoeias are non-random subsets of floras, with some taxonomic groups over- or under-represented. Moerman [Moerman, D.E., 1979. Symbols and selectivity: a statistical analysis of Native American medical ethnobotany, Journal of Ethnopharmacology 1, 111-119] introduced linear regression/residual analysis to examine these patterns. However, regression, the commonly-employed analysis, suffers from several statistical flaws. We use contingency table and binomial analyses to examine patterns of Shuar medicinal plant use (from Amazonian Ecuador). We first analyzed the Shuar data using Moerman's approach, modified to better meet requirements of linear regression analysis. Second, we assessed the exact randomization contingency table test for goodness of fit. Third, we developed a binomial model to test for non-random selection of plants in individual families. Modified regression models (which accommodated assumptions of linear regression) reduced R(2) to from 0.59 to 0.38, but did not eliminate all problems associated with regression analyses. Contingency table analyses revealed that the entire flora departs from the null model of equal proportions of medicinal plants in all families. In the binomial analysis, only 10 angiosperm families (of 115) differed significantly from the null model. These 10 families are largely responsible for patterns seen at higher taxonomic levels. Contingency table and binomial analyses offer an easy and statistically valid alternative to the regression approach.

  14. Weighted profile likelihood-based confidence interval for the difference between two proportions with paired binomial data.

    Science.gov (United States)

    Pradhan, Vivek; Saha, Krishna K; Banerjee, Tathagata; Evans, John C

    2014-07-30

    Inference on the difference between two binomial proportions in the paired binomial setting is often an important problem in many biomedical investigations. Tang et al. (2010, Statistics in Medicine) discussed six methods to construct confidence intervals (henceforth, we abbreviate it as CI) for the difference between two proportions in paired binomial setting using method of variance estimates recovery. In this article, we propose weighted profile likelihood-based CIs for the difference between proportions of a paired binomial distribution. However, instead of the usual likelihood, we use weighted likelihood that is essentially making adjustments to the cell frequencies of a 2 × 2 table in the spirit of Agresti and Min (2005, Statistics in Medicine). We then conduct numerical studies to compare the performances of the proposed CIs with that of Tang et al. and Agresti and Min in terms of coverage probabilities and expected lengths. Our numerical study clearly indicates that the weighted profile likelihood-based intervals and Jeffreys interval (cf. Tang et al.) are superior in terms of achieving the nominal level, and in terms of expected lengths, they are competitive. Finally, we illustrate the use of the proposed CIs with real-life examples. Copyright © 2014 John Wiley & Sons, Ltd.

  15. The Explicit Identities for Spectral Norms of Circulant-Type Matrices Involving Binomial Coefficients and Harmonic Numbers

    Directory of Open Access Journals (Sweden)

    Jianwei Zhou

    2014-01-01

    Full Text Available The explicit formulae of spectral norms for circulant-type matrices are investigated; the matrices are circulant matrix, skew-circulant matrix, and g-circulant matrix, respectively. The entries are products of binomial coefficients with harmonic numbers. Explicit identities for these spectral norms are obtained. Employing these approaches, some numerical tests are listed to verify the results.

  16. An algorithm for sequential tail value at risk for path-independent payoffs in a binomial tree

    NARCIS (Netherlands)

    Roorda, Berend

    2010-01-01

    We present an algorithm that determines Sequential Tail Value at Risk (STVaR) for path-independent payoffs in a binomial tree. STVaR is a dynamic version of Tail-Value-at-Risk (TVaR) characterized by the property that risk levels at any moment must be in the range of risk levels later on. The

  17. Comparison and Field Validation of Binomial Sampling Plans for Oligonychus perseae (Acari: Tetranychidae) on Hass Avocado in Southern California.

    Science.gov (United States)

    Lara, Jesus R; Hoddle, Mark S

    2015-08-01

    Oligonychus perseae Tuttle, Baker, & Abatiello is a foliar pest of 'Hass' avocados [Persea americana Miller (Lauraceae)]. The recommended action threshold is 50-100 motile mites per leaf, but this count range and other ecological factors associated with O. perseae infestations limit the application of enumerative sampling plans in the field. Consequently, a comprehensive modeling approach was implemented to compare the practical application of various binomial sampling models for decision-making of O. perseae in California. An initial set of sequential binomial sampling models were developed using three mean-proportion modeling techniques (i.e., Taylor's power law, maximum likelihood, and an empirical model) in combination with two-leaf infestation tally thresholds of either one or two mites. Model performance was evaluated using a robust mite count database consisting of >20,000 Hass avocado leaves infested with varying densities of O. perseae and collected from multiple locations. Operating characteristic and average sample number results for sequential binomial models were used as the basis to develop and validate a standardized fixed-size binomial sampling model with guidelines on sample tree and leaf selection within blocks of avocado trees. This final validated model requires a leaf sampling cost of 30 leaves and takes into account the spatial dynamics of O. perseae to make reliable mite density classifications for a 50-mite action threshold. Recommendations for implementing this fixed-size binomial sampling plan to assess densities of O. perseae in commercial California avocado orchards are discussed. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Entropy, energy and negativity in Fermi-resonance coupled states of substituted methanes

    International Nuclear Information System (INIS)

    Hou Xiwen; Wan Mingfang; Ma Zhongqi

    2010-01-01

    Several measures of entanglement have attracted considerable interest in the relationship of a measure of entanglement with other quantities. The dynamics of entropy, energy and negativity is studied for Fermi-resonance coupled vibrations in substituted methanes with three kinds of initial mixed states, which are the mixed density matrices of binomial states, thermal states and squeezed states on two vibrational modes, respectively. It is demonstrated that for mixed binomial states and mixed thermal states with small magnitudes the entropies of the stretch and the bend are anti-correlated in the same oscillatory frequency, so do the energies for each kind of state with small magnitudes, whereas the entropies exhibit positive correlations with the corresponding energies. Furthermore, for small magnitudes quantum mutual entropy is positively correlated with the interacting energy. Analytic forms of entropies and energies are provided with initial conditions in which they are stationary, and the agreement between analytic and numerical simulations is satisfactory. The dynamical entanglement measured by negativity is examined for those states and conditions. It is shown that negativity displays a sudden death for mixed binomial states and mixed thermal states with small magnitudes, and the time-averaged negativity has the minimal value under the conditions of stationary entropies and energies. Moreover, negativity is positively correlated with the mutual entropy and the interacting energy just for mixed squeezed states with small magnitudes. Those are useful for molecular quantum information processing and dynamical entanglement.

  19. A Double Hurdle Approach

    African Journals Online (AJOL)

    2017-05-01

    May 1, 2017 ... assumed to be exogenous in the loan default and rate of default models. Study Area, Data and ... amount [LNAMT] is the total amount of money taken as loan and is expected to increase probability and rate of .... This implies that type of enterprise is truly exogenous in relation to the probability of default.

  20. Evaluation of Single or Double Hurdle Sanitizer Applications in Simulated Field or Packing Shed Operations for Cantaloupes Contaminated with Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Cathy C. Webb

    2015-04-01

    Full Text Available Listeria monocytogenes contamination of cantaloupes has become a serious concern as contaminated cantaloupes led to a deadly outbreak in the United States in 2011. To reduce cross-contamination between cantaloupes and to reduce resident populations on contaminated melons, application of sanitizers in packing shed wash water is recommended. The sanitizing agent of 5% levulinic acid and 2% sodium dodecyl sulfate (SDS applied as a single hurdle in either a simulated dump or dip treatment significantly reduced L. monocytogenes to lower levels at the stem scar compared to a simulated dump treatment employing 200 ppm chlorine; however pathogen reductions on the rind tissue were not significantly different. Double hurdle approaches employing two sequential packing plant treatments with different sanitizers revealed decreased reduction of L. monocytogenes at the stem scar. In contrast, application of sanitizers both in the field and at the packing plant led to greater L. monocytogenes population reductions than if sanitizers were only applied at the packing plant.

  1. Enhancing the lethal effect of high-intensity pulsed electric field in milk by antimicrobial compounds as combined hurdles.

    Science.gov (United States)

    Sobrino-López, A; Martín-Belloso, O

    2008-05-01

    High-intensity pulsed electric field (HIPEF) is a nonthermal treatment studied for its wide antimicrobial spectrum on liquid food, including milk and dairy products. Moreover, the antimicrobial effect of HIPEF may be enhanced by combining HIPEF with other treatments as hurdles. Nisin and lysozyme are natural antimicrobial compounds that could be used in combination with HIPEF. Therefore, the purpose of this study was to determine the effect of combining HIPEF with the addition of nisin and lysozyme to milk inoculated with Staphylococcus aureus with regard to different process variables. The individual addition of nisin and lysozyme did not produce any reduction in cell population within the proposed range of concentrations, whereas their combination resulted in a pH-dependent microbial death of Staph. aureus. The addition of nisin and lysozyme to milk combined with HIPEF treatment resulted in a synergistic effect. Applying a 1,200-micros HIPEF treatment time to milk at pH 6.8 containing 1 IU/mL of nisin and 300 IU/mL of lysozyme resulted in a reduction of more than 6.2 log units of Staph. aureus. Final counts resulting from the addition of nisin and lysozyme and applying HIPEF strongly depended on both the sequence of application and the milk pH. Thus, more research is needed to elucidate the mode of action of synergism as well as the role of different process variables, although the use of HIPEF in combination with antimicrobial compounds such as nisin and lysozyme is shown to be potentially useful in processing milk and dairy products.

  2. Binomial Distribution Sample Confidence Intervals Estimation 7. Absolute Risk Reduction and ARR-like Expressions

    Directory of Open Access Journals (Sweden)

    Andrei ACHIMAŞ CADARIU

    2004-08-01

    Full Text Available Assessments of a controlled clinical trial suppose to interpret some key parameters as the controlled event rate, experimental event date, relative risk, absolute risk reduction, relative risk reduction, number needed to treat when the effect of the treatment are dichotomous variables. Defined as the difference in the event rate between treatment and control groups, the absolute risk reduction is the parameter that allowed computing the number needed to treat. The absolute risk reduction is compute when the experimental treatment reduces the risk for an undesirable outcome/event. In medical literature when the absolute risk reduction is report with its confidence intervals, the method used is the asymptotic one, even if it is well know that may be inadequate. The aim of this paper is to introduce and assess nine methods of computing confidence intervals for absolute risk reduction and absolute risk reduction – like function.Computer implementations of the methods use the PHP language. Methods comparison uses the experimental errors, the standard deviations, and the deviation relative to the imposed significance level for specified sample sizes. Six methods of computing confidence intervals for absolute risk reduction and absolute risk reduction-like functions were assessed using random binomial variables and random sample sizes.The experiments shows that the ADAC, and ADAC1 methods obtains the best overall performance of computing confidence intervals for absolute risk reduction.

  3. Binomial Test Method for Determining Probability of Detection Capability for Fracture Critical Applications

    Science.gov (United States)

    Generazio, Edward R.

    2011-01-01

    The capability of an inspection system is established by applications of various methodologies to determine the probability of detection (POD). One accepted metric of an adequate inspection system is that for a minimum flaw size and all greater flaw sizes, there is 0.90 probability of detection with 95% confidence (90/95 POD). Directed design of experiments for probability of detection (DOEPOD) has been developed to provide an efficient and accurate methodology that yields estimates of POD and confidence bounds for both Hit-Miss or signal amplitude testing, where signal amplitudes are reduced to Hit-Miss by using a signal threshold Directed DOEPOD uses a nonparametric approach for the analysis or inspection data that does require any assumptions about the particular functional form of a POD function. The DOEPOD procedure identifies, for a given sample set whether or not the minimum requirement of 0.90 probability of detection with 95% confidence is demonstrated for a minimum flaw size and for all greater flaw sizes (90/95 POD). The DOEPOD procedures are sequentially executed in order to minimize the number of samples needed to demonstrate that there is a 90/95 POD lower confidence bound at a given flaw size and that the POD is monotonic for flaw sizes exceeding that 90/95 POD flaw size. The conservativeness of the DOEPOD methodology results is discussed. Validated guidelines for binomial estimation of POD for fracture critical inspection are established.

  4. Design of Ultra-Wideband Tapered Slot Antenna by Using Binomial Transformer with Corrugation

    Science.gov (United States)

    Chareonsiri, Yosita; Thaiwirot, Wanwisa; Akkaraekthalin, Prayoot

    2017-05-01

    In this paper, the tapered slot antenna (TSA) with corrugation is proposed for UWB applications. The multi-section binomial transformer is used to design taper profile of the proposed TSA that does not involve using time consuming optimization. A step-by-step procedure for synthesis of the step impedance values related with step slot widths of taper profile is presented. The smooth taper can be achieved by fitting the smoothing curve to the entire step slot. The design of TSA based on this method yields results with a quite flat gain and wide impedance bandwidth covering UWB spectrum from 3.1 GHz to 10.6 GHz. To further improve the radiation characteristics, the corrugation is added on the both edges of the proposed TSA. The effects of different corrugation shapes on the improvement of antenna gain and front-to-back ratio (F-to-B ratio) are investigated. To demonstrate the validity of the design, the prototypes of TSA without and with corrugation are fabricated and measured. The results show good agreement between simulation and measurement.

  5. A binomial modeling approach for upscaling colloid transport under unfavorable conditions: organic prediction of extended tailing

    Science.gov (United States)

    Hilpert, Markus; Rasmuson, Anna; Johnson, William

    2017-04-01

    Transport of colloids in saturated porous media is significantly influenced by colloidal interactions with grain surfaces. Near-surface fluid domain colloids experience relatively low fluid drag and relatively strong colloidal forces that slow their down-gradient translation relative to colloids in bulk fluid. Near surface fluid domain colloids may re-enter into the bulk fluid via diffusion (nanoparticles) or expulsion at rear flow stagnation zones, they may immobilize (attach) via strong primary minimum interactions, or they may move along a grain-to-grain contact to the near surface fluid domain of an adjacent grain. We introduce a simple model that accounts for all possible permutations of mass transfer within a dual pore and grain network. The primary phenomena thereby represented in the model are mass transfer of colloids between the bulk and near-surface fluid domains and immobilization onto grain surfaces. Colloid movement is described by a sequence of trials in a series of unit cells, and the binomial distribution is used to calculate the probabilities of each possible sequence. Pore-scale simulations provide mechanistically-determined likelihoods and timescales associated with the above pore-scale colloid mass transfer processes, whereas the network-scale model employs pore and grain topology to determine probabilities of transfer from up-gradient bulk and near-surface fluid domains to down-gradient bulk and near-surface fluid domains. Inter-grain transport of colloids in the near surface fluid domain can cause extended tailing.

  6. The binomial work-health in the transit of Curitiba city.

    Science.gov (United States)

    Tokars, Eunice; Moro, Antonio Renato Pereira; Cruz, Roberto Moraes

    2012-01-01

    The working activity in traffic of the big cities complex interacts with the environment is often in unsafe and unhealthy imbalance favoring the binomial work - health. The aim of this paper was to analyze the relationship between work and health of taxi drivers in Curitiba, Brazil. This cross-sectional observational study with 206 individuals used a questionnaire on the organization's profile and perception of the environment and direct observation of work. It was found that the majority are male, aged between 26 and 49 years and has a high school degree. They are sedentary, like making a journey from 8 to 12 hours. They consider a stressful profession, related low back pain and are concerned about safety and accidents. 40% are smokers and consume alcoholic drink and 65% do not have or do not use devices of comfort. Risk factors present in the daily taxi constraints cause physical, cognitive and organizational and can affect your performance. It is concluded that the taxi drivers must change the unhealthy lifestyle, requiring a more efficient management of government authorities for this work is healthy and safe for all involved.

  7. The Night-Death binomial as a poetic ploy - a cross-cultural look from the graveyard poets to expressionism

    Directory of Open Access Journals (Sweden)

    Lioba Simon-Schuhmacher

    2015-11-01

    Full Text Available The essay describes the use of the Night-Death binomial and tracks its evolution from the eighteenth century to Expressionism across Great Britain, Germany, Spain, and Austria, at the hand of poems such as Edward Young’s Night Thoughts (1745, Novalis’s Hymnen an die Nacht, (1800, José Blanco White’s sonnet “Night and Death” (1828, and Georg Trakl’s “Verwandlung des Bösen” (1914. Romanticism brought along a preference for the nocturnal: night, moonlight, shades and shadows, mist and mystery, somber mood, morbidity, and death, as opposed to the Enlightenment’s predilection for day, light, clarity, and life. The essay analyses how poets from different national contexts and ages employ images and symbols of the night to create an association with death. It furthermore shows how, with varying attitudes and results, they manage to convert this binomial into a poetic ploy.

  8. Enumerative and binomial sequential sampling plans for the multicolored Asian lady beetle (Coleoptera: Coccinellidae) in wine grapes.

    Science.gov (United States)

    Galvan, T L; Burkness, E C; Hutchison, W D

    2007-06-01

    To develop a practical integrated pest management (IPM) system for the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in wine grapes, we assessed the spatial distribution of H. axyridis and developed eight sampling plans to estimate adult density or infestation level in grape clusters. We used 49 data sets collected from commercial vineyards in 2004 and 2005, in Minnesota and Wisconsin. Enumerative plans were developed using two precision levels (0.10 and 0.25); the six binomial plans reflected six unique action thresholds (3, 7, 12, 18, 22, and 31% of cluster samples infested with at least one H. axyridis). The spatial distribution of H. axyridis in wine grapes was aggregated, independent of cultivar and year, but it was more randomly distributed as mean density declined. The average sample number (ASN) for each sampling plan was determined using resampling software. For research purposes, an enumerative plan with a precision level of 0.10 (SE/X) resulted in a mean ASN of 546 clusters. For IPM applications, the enumerative plan with a precision level of 0.25 resulted in a mean ASN of 180 clusters. In contrast, the binomial plans resulted in much lower ASNs and provided high probabilities of arriving at correct "treat or no-treat" decisions, making these plans more efficient for IPM applications. For a tally threshold of one adult per cluster, the operating characteristic curves for the six action thresholds provided binomial sequential sampling plans with mean ASNs of only 19-26 clusters, and probabilities of making correct decisions between 83 and 96%. The benefits of the binomial sampling plans are discussed within the context of improving IPM programs for wine grapes.

  9. Comparison of beta-binomial regression model approaches to analyze health-related quality of life data.

    Science.gov (United States)

    Najera-Zuloaga, Josu; Lee, Dae-Jin; Arostegui, Inmaculada

    2017-01-01

    Health-related quality of life has become an increasingly important indicator of health status in clinical trials and epidemiological research. Moreover, the study of the relationship of health-related quality of life with patients and disease characteristics has become one of the primary aims of many health-related quality of life studies. Health-related quality of life scores are usually assumed to be distributed as binomial random variables and often highly skewed. The use of the beta-binomial distribution in the regression context has been proposed to model such data; however, the beta-binomial regression has been performed by means of two different approaches in the literature: (i) beta-binomial distribution with a logistic link; and (ii) hierarchical generalized linear models. None of the existing literature in the analysis of health-related quality of life survey data has performed a comparison of both approaches in terms of adequacy and regression parameter interpretation context. This paper is motivated by the analysis of a real data application of health-related quality of life outcomes in patients with Chronic Obstructive Pulmonary Disease, where the use of both approaches yields to contradictory results in terms of covariate effects significance and consequently the interpretation of the most relevant factors in health-related quality of life. We present an explanation of the results in both methodologies through a simulation study and address the need to apply the proper approach in the analysis of health-related quality of life survey data for practitioners, providing an R package.

  10. Criterios sobre el uso de la distribución normal para aproximar la distribución binomial

    OpenAIRE

    Ortiz Pinilla, Jorge; Castro, Amparo; Neira, Tito; Torres, Pedro; Castañeda, Javier

    2012-01-01

    Las dos reglas empíricas más conocidas para aceptar la aproximación normal de la distribución binomial carecen de regularidad en el control del margen de error cometido al utilizar la aproximación normal. Se propone un criterio y algunas fórmulas para controlarlo cerca de algunos valores escogidos para el error máximo.

  11. Reducing Monte Carlo error in the Bayesian estimation of risk ratios using log-binomial regression models.

    Science.gov (United States)

    Salmerón, Diego; Cano, Juan A; Chirlaque, María D

    2015-08-30

    In cohort studies, binary outcomes are very often analyzed by logistic regression. However, it is well known that when the goal is to estimate a risk ratio, the logistic regression is inappropriate if the outcome is common. In these cases, a log-binomial regression model is preferable. On the other hand, the estimation of the regression coefficients of the log-binomial model is difficult owing to the constraints that must be imposed on these coefficients. Bayesian methods allow a straightforward approach for log-binomial regression models and produce smaller mean squared errors in the estimation of risk ratios than the frequentist methods, and the posterior inferences can be obtained using the software WinBUGS. However, Markov chain Monte Carlo methods implemented in WinBUGS can lead to large Monte Carlo errors in the approximations to the posterior inferences because they produce correlated simulations, and the accuracy of the approximations are inversely related to this correlation. To reduce correlation and to improve accuracy, we propose a reparameterization based on a Poisson model and a sampling algorithm coded in R. Copyright © 2015 John Wiley & Sons, Ltd.

  12. The Sequential Probability Ratio Test: An efficient alternative to exact binomial testing for Clean Water Act 303(d) evaluation.

    Science.gov (United States)

    Chen, Connie; Gribble, Matthew O; Bartroff, Jay; Bay, Steven M; Goldstein, Larry

    2017-05-01

    The United States's Clean Water Act stipulates in section 303(d) that states must identify impaired water bodies for which total maximum daily loads (TMDLs) of pollution inputs into water bodies are developed. Decision-making procedures about how to list, or delist, water bodies as impaired, or not, per Clean Water Act 303(d) differ across states. In states such as California, whether or not a particular monitoring sample suggests that water quality is impaired can be regarded as a binary outcome variable, and California's current regulatory framework invokes a version of the exact binomial test to consolidate evidence across samples and assess whether the overall water body complies with the Clean Water Act. Here, we contrast the performance of California's exact binomial test with one potential alternative, the Sequential Probability Ratio Test (SPRT). The SPRT uses a sequential testing framework, testing samples as they become available and evaluating evidence as it emerges, rather than measuring all the samples and calculating a test statistic at the end of the data collection process. Through simulations and theoretical derivations, we demonstrate that the SPRT on average requires fewer samples to be measured to have comparable Type I and Type II error rates as the current fixed-sample binomial test. Policymakers might consider efficient alternatives such as SPRT to current procedure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Negative urgency, distress tolerance, and substance abuse among college students.

    Science.gov (United States)

    Kaiser, Alison J; Milich, Richard; Lynam, Donald R; Charnigo, Richard J

    2012-10-01

    Negative affect has been consistently linked with substance use/problems in prior research. The present study sought to build upon these findings by exploring how an individual's characteristic responding to negative affect impacts substance abuse risk. Trait negative affect was examined in relation to substance abuse outcomes along with two variables tapping into response to negative affect: distress tolerance, an individual's perceived ability to tolerate negative affect, and negative urgency, the tendency to act rashly while experiencing distress. Participants were 525 first-year college students (48.1% male, 81.1% Caucasian), who completed self-report measures assessing personality traits and alcohol-related problems, and a structured interview assessing past and current substance use. Relations were tested using zero-inflated negative binomial regression models, and each of the personality variables was tested in a model on its own, and in a model where all three traits were accounted for. Negative urgency emerged as the best predictor, relating to every one of the substance use outcome variables even when trait negative affect and distress tolerance were accounted for. These findings suggest that negative urgency is an important factor to consider in developing prevention and intervention efforts aimed at reducing substance use and problems. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. A binomial modeling approach for upscaling colloid transport under unfavorable conditions: Emergent prediction of extended tailing

    Science.gov (United States)

    Hilpert, Markus; Rasmuson, Anna; Johnson, William P.

    2017-07-01

    Colloid transport in saturated porous media is significantly influenced by colloidal interactions with grain surfaces. Near-surface fluid domain colloids experience relatively low fluid drag and relatively strong colloidal forces that slow their downgradient translation relative to colloids in bulk fluid. Near-surface fluid domain colloids may reenter into the bulk fluid via diffusion (nanoparticles) or expulsion at rear flow stagnation zones, they may immobilize (attach) via primary minimum interactions, or they may move along a grain-to-grain contact to the near-surface fluid domain of an adjacent grain. We introduce a simple model that accounts for all possible permutations of mass transfer within a dual pore and grain network. The primary phenomena thereby represented in the model are mass transfer of colloids between the bulk and near-surface fluid domains and immobilization. Colloid movement is described by a Markov chain, i.e., a sequence of trials in a 1-D network of unit cells, which contain a pore and a grain. Using combinatorial analysis, which utilizes the binomial coefficient, we derive the residence time distribution, i.e., an inventory of the discrete colloid travel times through the network and of their probabilities to occur. To parameterize the network model, we performed mechanistic pore-scale simulations in a single unit cell that determined the likelihoods and timescales associated with the above colloid mass transfer processes. We found that intergrain transport of colloids in the near-surface fluid domain can cause extended tailing, which has traditionally been attributed to hydrodynamic dispersion emanating from flow tortuosity of solute trajectories.

  15. Avoiding negative populations in explicit Poisson tau-leaping.

    Science.gov (United States)

    Cao, Yang; Gillespie, Daniel T; Petzold, Linda R

    2005-08-01

    The explicit tau-leaping procedure attempts to speed up the stochastic simulation of a chemically reacting system by approximating the number of firings of each reaction channel during a chosen time increment tau as a Poisson random variable. Since the Poisson random variable can have arbitrarily large sample values, there is always the possibility that this procedure will cause one or more reaction channels to fire so many times during tau that the population of some reactant species will be driven negative. Two recent papers have shown how that unacceptable occurrence can be avoided by replacing the Poisson random variables with binomial random variables, whose values are naturally bounded. This paper describes a modified Poisson tau-leaping procedure that also avoids negative populations, but is easier to implement than the binomial procedure. The new Poisson procedure also introduces a second control parameter, whose value essentially dials the procedure from the original Poisson tau-leaping at one extreme to the exact stochastic simulation algorithm at the other; therefore, the modified Poisson procedure will generally be more accurate than the original Poisson procedure.

  16. Binomial mitotic segregation of MYCN-carrying double minutes in neuroblastoma illustrates the role of randomness in oncogene amplification.

    Directory of Open Access Journals (Sweden)

    Gisela Lundberg

    2008-08-01

    Full Text Available Amplification of the oncogene MYCN in double minutes (DMs is a common finding in neuroblastoma (NB. Because DMs lack centromeric sequences it has been unclear how NB cells retain and amplify extrachromosomal MYCN copies during tumour development.We show that MYCN-carrying DMs in NB cells translocate from the nuclear interior to the periphery of the condensing chromatin at transition from interphase to prophase and are preferentially located adjacent to the telomere repeat sequences of the chromosomes throughout cell division. However, DM segregation was not affected by disruption of the telosome nucleoprotein complex and DMs readily migrated from human to murine chromatin in human/mouse cell hybrids, indicating that they do not bind to specific positional elements in human chromosomes. Scoring DM copy-numbers in ana/telophase cells revealed that DM segregation could be closely approximated by a binomial random distribution. Colony-forming assay demonstrated a strong growth-advantage for NB cells with high DM (MYCN copy-numbers, compared to NB cells with lower copy-numbers. In fact, the overall distribution of DMs in growing NB cell populations could be readily reproduced by a mathematical model assuming binomial segregation at cell division combined with a proliferative advantage for cells with high DM copy-numbers.Binomial segregation at cell division explains the high degree of MYCN copy-number variability in NB. Our findings also provide a proof-of-principle for oncogene amplification through creation of genetic diversity by random events followed by Darwinian selection.

  17. Non-binomial distribution of palladium Kα Ln X-ray satellites emitted after excitation by 16O ions

    International Nuclear Information System (INIS)

    Rymuza, P.; Sujkowski, Z.; Carlen, M.; Dousse, J.C.; Gasser, M.; Kern, J.; Perny, B.; Rheme, C.

    1988-02-01

    The palladium K α L n X-ray satellites spectrum emitted after excitation by 5.4 MeV/u 16 O ions has been measured. The distribution of the satellites yield is found to be significantly narrower than the binomial one. The deviations can be accounted for by assuming that the L-shell ionization is due to two uncorrelated processes: the direct ionization by impact and the electron capture to the K-shell of the projectile. 12 refs., 1 fig., 1 tab. (author)

  18. Application of Binomial Model and Market Asset Declaimer Methodology for Valuation of Abandon and Expand Options. The Case Study

    Directory of Open Access Journals (Sweden)

    Paweł Mielcarz

    2007-06-01

    Full Text Available The article presents a case study of valuation of real options included in a investment project. The main goal of the article is to present the calculation and methodological issues of application the methodology for real option valuation. In order to do it there are used the binomial model and Market Asset Declaimer methodology. The project presented in the article concerns the introduction of radio station to a new market. It includes two valuable real options: to abandon the project and to expand.

  19. Effects of sonication and ultraviolet-C treatment as a hurdle concept on quality attributes of Chokanan mango (Mangifera indica L.) juice.

    Science.gov (United States)

    Santhirasegaram, Vicknesha; Razali, Zuliana; Somasundram, Chandran

    2015-04-01

    The growing demand for fresh-like food products has encouraged the development of hurdle technology of non-thermal processing. In this study, freshly squeezed Chokanan mango juice was treated by paired combinations of sonication (for 15 and 30 min at 25 ℃, 40 kHz frequency) and UV-C treatment (for 15 and 30 min at 25 ℃). Selected physicochemical properties, antioxidant activities, microbial inactivation and other quality parameters of combined treated juice were compared to conventional thermal treatment (at 90 ℃ for 60 s). After thermal and combined treatment, no significant changes occurred in physicochemical properties. A significant increase in extractability of carotenoids (15%), polyphenols (37%), flavonoids (35%) and enhancement in antioxidant capacity was observed after combined treatment. Thermal and combined treatment exhibited significant reduction in microbial load. Results obtained support the use of sonication and UV-C in a hurdle technology to improve the quality of Chokanan mango juice along with safety standards. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  20. Hurdles to the global antipolio campaign in Pakistan: an outline of the current status and future prospects to achieve a polio free world.

    Science.gov (United States)

    Khan, Tariq; Qazi, Javaria

    2013-08-01

    The Global Polio Eradication Initiative to eradicate polio completely by the year 2000 has been successful, except for three endemic and some non-endemic countries. Pakistan, one of the three endemic polio reservoirs, is posing a serious threat to the success of the initiative. Currently, the expanded programme on immunisation has been geared to win the race over polio virus in Pakistan. After the remarkable decrease in polio cases from 198 in 2011 to only 58 in 2012, Pakistan seemed to be at the verge of success. However, hurdles continue to retard the campaign. The war against terrorism, misconceptions about polio vaccine, religious misinterpretations, frustration among vaccinators, lack of awareness, social considerations, natural calamities, inaccessibility, and inefficient vaccines and so on are continually rupturing the foundations of the worldwide initiative in the country. Weak health management is found at the hub of majority of the challenges. Stricter policies, well managed and supervised plans and strategic actions, risk analysis and enhanced communication may help giving the final punch to polio virus in the country. Analysis suggested that there is some literature available on the challenges to polio elimination, yet there is not a single publication up to date that considers all the possible hurdles in a single manuscript. This paper sorts out the breaches that hamper the goal of eliminating polio from Pakistan. We have evaluated all the possible barriers and explained them with a perspective that will help develop area specific strategies against polio virus and thus eradicate polio virus from the world.

  1. The impact of adolescent tobacco-related associative memory on smoking trajectory: an application of negative binomial regression to highly skewed longitudinal data.

    Science.gov (United States)

    Kelly, Adrian B; Haynes, Michele A; Marlatt, G Alan

    2008-05-01

    Tobacco use is prevalent in adolescents and understanding factors that contribute to smoking uptake remains a critical public health priority. While there is now good support for the role of implicit (preconscious) cognitive processing in accounting for changes in drug use, these models have not been applied to tobacco use. Longitudinal analysis of smoking data presents unique problems, because these data are usually highly positively skewed (with excess zeros) and render conventional statistical tools (e.g., OLS regression) largely inappropriate. This study advanced the application of implicit memory theory to adolescent smoking by adopting statistical methods that do not rely on assumptions of normality, and produce robust estimates from data with correlated observations. The study examined the longitudinal association of implicit tobacco-related memory associations (TMAs) and smoking in 114 Australian high school students. Participants completed TMA tasks and behavioural checklists designed to obscure the tobacco-related focus of the study. Results showed that the TMA-smoking association remained significant when accounting for within-subject variability, and TMAs at Time 1 were modestly associated with smoking at Time 2 after accounting for within subject variability. Students with stronger preconscious smoking-related associations appear to be at greater risk of smoking. Strategies that target implicit TMAs may be an effective early intervention or prevention tool. The statistical method will be of use in future research on adolescent smoking, and for research on other behavioural distributions that are highly positively skewed.

  2. Modelling noise in second generation sequencing forensic genetics STR data using a one-inflated (zero-truncated) negative binomial model

    DEFF Research Database (Denmark)

    Vilsen, Søren B.; Tvedebrink, Torben; Mogensen, Helle Smidt

    2015-01-01

    –10% of the total marker coverage. In comparison, our method resulted in three allelic drop-outs (true alleles below threshold), whereas the 10%-threshold induced 12 drop-outs. The non-filtered error reads (e.g. stutters, shoulders and reads with miscalled bases) will subsequently be modelled by different...

  3. Negative Binomial Fits to Multiplicity Distributions from Central Collisions of (16)O+Cu at 14.6A GeV/c and Intermittency

    Science.gov (United States)

    Tannenbaum, M. J.

    1994-01-01

    The concept of "Intermittency" was introduced by Bialas and Peschanski to try to explain the "large" fluctuations of multiplicity in restricted intervals of rapidity or pseudorapidity. A formalism was proposed to to study non-statistical (more precisely, non-Poisson) fluctuations as a function of the size of rapidity interval, and it was further suggested that the "spikes" in the rapidity fluctuations were evidence of fractal or intermittent behavior, in analogy to turbulence in fluid dynamics which is characterized by self-similar fluctuations at all scales-the absence of well defined scale of length.

  4. Comparison of robustness to outliers between robust poisson models and log-binomial models when estimating relative risks for common binary outcomes: a simulation study.

    Science.gov (United States)

    Chen, Wansu; Shi, Jiaxiao; Qian, Lei; Azen, Stanley P

    2014-06-26

    To estimate relative risks or risk ratios for common binary outcomes, the most popular model-based methods are the robust (also known as modified) Poisson and the log-binomial regression. Of the two methods, it is believed that the log-binomial regression yields more efficient estimators because it is maximum likelihood based, while the robust Poisson model may be less affected by outliers. Evidence to support the robustness of robust Poisson models in comparison with log-binomial models is very limited. In this study a simulation was conducted to evaluate the performance of the two methods in several scenarios where outliers existed. The findings indicate that for data coming from a population where the relationship between the outcome and the covariate was in a simple form (e.g. log-linear), the two models yielded comparable biases and mean square errors. However, if the true relationship contained a higher order term, the robust Poisson models consistently outperformed the log-binomial models even when the level of contamination is low. The robust Poisson models are more robust (or less sensitive) to outliers compared to the log-binomial models when estimating relative risks or risk ratios for common binary outcomes. Users should be aware of the limitations when choosing appropriate models to estimate relative risks or risk ratios.

  5. Interrelationships Between Receiver/Relative Operating Characteristics Display, Binomial, Logit, and Bayes' Rule Probability of Detection Methodologies

    Science.gov (United States)

    Generazio, Edward R.

    2014-01-01

    Unknown risks are introduced into failure critical systems when probability of detection (POD) capabilities are accepted without a complete understanding of the statistical method applied and the interpretation of the statistical results. The presence of this risk in the nondestructive evaluation (NDE) community is revealed in common statements about POD. These statements are often interpreted in a variety of ways and therefore, the very existence of the statements identifies the need for a more comprehensive understanding of POD methodologies. Statistical methodologies have data requirements to be met, procedures to be followed, and requirements for validation or demonstration of adequacy of the POD estimates. Risks are further enhanced due to the wide range of statistical methodologies used for determining the POD capability. Receiver/Relative Operating Characteristics (ROC) Display, simple binomial, logistic regression, and Bayes' rule POD methodologies are widely used in determining POD capability. This work focuses on Hit-Miss data to reveal the framework of the interrelationships between Receiver/Relative Operating Characteristics Display, simple binomial, logistic regression, and Bayes' Rule methodologies as they are applied to POD. Knowledge of these interrelationships leads to an intuitive and global understanding of the statistical data, procedural and validation requirements for establishing credible POD estimates.

  6. Beta-Binomial Model for the Detection of Rare Mutations in Pooled Next-Generation Sequencing Experiments.

    Science.gov (United States)

    Jakaitiene, Audrone; Avino, Mariano; Guarracino, Mario Rosario

    2017-04-01

    Against diminishing costs, next-generation sequencing (NGS) still remains expensive for studies with a large number of individuals. As cost saving, sequencing genome of pools containing multiple samples might be used. Currently, there are many software available for the detection of single-nucleotide polymorphisms (SNPs). Sensitivity and specificity depend on the model used and data analyzed, indicating that all software have space for improvement. We use beta-binomial model to detect rare mutations in untagged pooled NGS experiments. We propose a multireference framework for pooled data with ability being specific up to two patients affected by neuromuscular disorders (NMD). We assessed the results comparing with The Genome Analysis Toolkit (GATK), CRISP, SNVer, and FreeBayes. Our results show that the multireference approach applying beta-binomial model is accurate in predicting rare mutations at 0.01 fraction. Finally, we explored the concordance of mutations between the model and software, checking their involvement in any NMD-related gene. We detected seven novel SNPs, for which the functional analysis produced enriched terms related to locomotion and musculature.

  7. Spiritual and ceremonial plants in North America: an assessment of Moerman's ethnobotanical database comparing Residual, Binomial, Bayesian and Imprecise Dirichlet Model (IDM) analysis.

    Science.gov (United States)

    Turi, Christina E; Murch, Susan J

    2013-07-09

    Ethnobotanical research and the study of plants used for rituals, ceremonies and to connect with the spirit world have led to the discovery of many novel psychoactive compounds such as nicotine, caffeine, and cocaine. In North America, spiritual and ceremonial uses of plants are well documented and can be accessed online via the University of Michigan's Native American Ethnobotany Database. The objective of the study was to compare Residual, Bayesian, Binomial and Imprecise Dirichlet Model (IDM) analyses of ritual, ceremonial and spiritual plants in Moerman's ethnobotanical database and to identify genera that may be good candidates for the discovery of novel psychoactive compounds. The database was queried with the following format "Family Name AND Ceremonial OR Spiritual" for 263 North American botanical families. Spiritual and ceremonial flora consisted of 86 families with 517 species belonging to 292 genera. Spiritual taxa were then grouped further into ceremonial medicines and items categories. Residual, Bayesian, Binomial and IDM analysis were performed to identify over and under-utilized families. The 4 statistical approaches were in good agreement when identifying under-utilized families but large families (>393 species) were underemphasized by Binomial, Bayesian and IDM approaches for over-utilization. Residual, Binomial, and IDM analysis identified similar families as over-utilized in the medium (92-392 species) and small (Binomial analysis when separated into small, medium and large families. The Bayesian, Binomial and IDM approaches identified different genera as potentially important. Species belonging to the genus Artemisia and Ligusticum were most consistently identified and may be valuable in future studies of the ethnopharmacology. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Modeling Zero-Inflated and Overdispersed Count Data: An Empirical Study of School Suspensions

    Science.gov (United States)

    Desjardins, Christopher David

    2016-01-01

    The purpose of this article is to develop a statistical model that best explains variability in the number of school days suspended. Number of school days suspended is a count variable that may be zero-inflated and overdispersed relative to a Poisson model. Four models were examined: Poisson, negative binomial, Poisson hurdle, and negative…

  9. Medication calculation and administration workshop and hurdle assessment increases student awareness towards the importance of safe practices to decrease medication errors in the future.

    Science.gov (United States)

    Wallace, Darlene; Woolley, Torres; Martin, David; Rasalam, Roy; Bellei, Maria

    2016-01-01

    Medication errors are the second most frequently reported hospital incident in Australia and are a global concern. A "Medication Calculation and Administration" workshop followed by a "hurdle" assessment (compulsory task mandating a minimum level of performance as a condition of passing the course) was introduced into Year 2 of the James Cook University medical curriculum to decrease dosage calculation and administration errors among graduates. This study evaluates the effectiveness of this educational activity as a long-term strategy to teach medical students' essential skills in calculating and administering medications. This longitudinal study used a pre- and post-test design to determine whether medical students retained their calculation and administration skills over a period of 4 years. The ability to apply basic mathematical skills to medication dose calculation, principles of safe administration (Part 1), and ability to access reference materials to check indications, contraindications, and writing the medication order with correct abbreviations (Part 2) were compared between Year 2 and 6 assessments. Scores for Parts 1, 2 and total scores were nearly identical from Year 2 to Year 6 (P = 0.663, 0.408, and 0.472, respectively), indicating minimal loss of knowledge by students in this period. Most Year 6 students (86%) were able to recall at least 5 of the "6 Rights of Medication Administration" while 84% reported accessing reference material and 91% reported checking their medical calculations. The "Medication Calculation and Administration" workshop with a combined formative and summative assessment - a "hurdle" - promotes long-term retention of essential clinical skills for medical students. These skills and an awareness of the problem are strategies to assist medical graduates in preventing future medication-related adverse events.

  10. Spatial modeling of rat bites and prediction of rat infestation in Peshawar valley using binomial kriging with logistic regression.

    Science.gov (United States)

    Ali, Asad; Zaidi, Farrah; Fatima, Syeda Hira; Adnan, Muhammad; Ullah, Saleem

    2018-03-24

    In this study, we propose to develop a geostatistical computational framework to model the distribution of rat bite infestation of epidemic proportion in Peshawar valley, Pakistan. Two species Rattus norvegicus and Rattus rattus are suspected to spread the infestation. The framework combines strengths of maximum entropy algorithm and binomial kriging with logistic regression to spatially model the distribution of infestation and to determine the individual role of environmental predictors in modeling the distribution trends. Our results demonstrate the significance of a number of social and environmental factors in rat infestations such as (I) high human population density; (II) greater dispersal ability of rodents due to the availability of better connectivity routes such as roads, and (III) temperature and precipitation influencing rodent fecundity and life cycle.

  11. Is “Hit and Run” a Single Word? The Processing of Irreversible Binomials in Neglect Dyslexia

    Science.gov (United States)

    Arcara, Giorgio; Lacaita, Graziano; Mattaloni, Elisa; Passarini, Laura; Mondini, Sara; Benincà, Paola; Semenza, Carlo

    2012-01-01

    The present study is the first neuropsychological investigation into the problem of the mental representation and processing of irreversible binomials (IBs), i.e., word pairs linked by a conjunction (e.g., “hit and run,” “dead or alive”). In order to test their lexical status, the phenomenon of neglect dyslexia is explored. People with left-sided neglect dyslexia show a clear lexical effect: they can read IBs better (i.e., by dropping the leftmost words less frequently) when their components are presented in their correct order. This may be taken as an indication that they treat these constructions as lexical, not decomposable, elements. This finding therefore constitutes strong evidence that IBs tend to be stored in the mental lexicon as a whole and that this whole form is preferably addressed in the retrieval process. PMID:22347199

  12. Type I error probability spending for post-market drug and vaccine safety surveillance with binomial data.

    Science.gov (United States)

    Silva, Ivair R

    2018-01-15

    Type I error probability spending functions are commonly used for designing sequential analysis of binomial data in clinical trials, but it is also quickly emerging for near-continuous sequential analysis of post-market drug and vaccine safety surveillance. It is well known that, for clinical trials, when the null hypothesis is not rejected, it is still important to minimize the sample size. Unlike in post-market drug and vaccine safety surveillance, that is not important. In post-market safety surveillance, specially when the surveillance involves identification of potential signals, the meaningful statistical performance measure to be minimized is the expected sample size when the null hypothesis is rejected. The present paper shows that, instead of the convex Type I error spending shape conventionally used in clinical trials, a concave shape is more indicated for post-market drug and vaccine safety surveillance. This is shown for both, continuous and group sequential analysis. Copyright © 2017 John Wiley & Sons, Ltd.

  13. Correcting for binomial measurement error in predictors in regression with application to analysis of DNA methylation rates by bisulfite sequencing.

    Science.gov (United States)

    Buonaccorsi, John; Prochenka, Agnieszka; Thoresen, Magne; Ploski, Rafal

    2016-09-30

    Motivated by a genetic application, this paper addresses the problem of fitting regression models when the predictor is a proportion measured with error. While the problem of dealing with additive measurement error in fitting regression models has been extensively studied, the problem where the additive error is of a binomial nature has not been addressed. The measurement errors here are heteroscedastic for two reasons; dependence on the underlying true value and changing sampling effort over observations. While some of the previously developed methods for treating additive measurement error with heteroscedasticity can be used in this setting, other methods need modification. A new version of simulation extrapolation is developed, and we also explore a variation on the standard regression calibration method that uses a beta-binomial model based on the fact that the true value is a proportion. Although most of the methods introduced here can be used for fitting non-linear models, this paper will focus primarily on their use in fitting a linear model. While previous work has focused mainly on estimation of the coefficients, we will, with motivation from our example, also examine estimation of the variance around the regression line. In addressing these problems, we also discuss the appropriate manner in which to bootstrap for both inferences and bias assessment. The various methods are compared via simulation, and the results are illustrated using our motivating data, for which the goal is to relate the methylation rate of a blood sample to the age of the individual providing the sample. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Negating the Verum

    DEFF Research Database (Denmark)

    Ørsnes, Bjarne

    2012-01-01

    an (aboutness-)topic. The negation of a verum predicate explains why preposed negation—like other constructions with verum-focus—fails to license strong negative polarity items and fails to rule out positive ones. The lack of a topic explains why preposed negation is preferred with non-referential subjects...

  15. Sentential Negation in English

    Science.gov (United States)

    Mowarin, Macaulay

    2009-01-01

    This paper undertakes a detailed analysis of sentential negation in the English language with Chomsky's Government-Binding theory of Transformational Grammar as theoretical model. It distinguishes between constituent and sentential negation in English. The essay identifies the exact position of Negation phrase in an English clause structure. It…

  16. Negative ion sources

    International Nuclear Information System (INIS)

    Ishikawa, Junzo; Takagi, Toshinori

    1983-01-01

    Negative ion sources have been originally developed at the request of tandem electrostatic accelerators, and hundreds of nA to several μA negative ion current has been obtained so far for various elements. Recently, the development of large current hydrogen negative ion sources has been demanded from the standpoint of the heating by neutral particle beam injection in nuclear fusion reactors. On the other hand, the physical properties of negative ions are interesting in the thin film formation using ions. Anyway, it is the present status that the mechanism of negative ion action has not been so fully investigated as positive ions because the history of negative ion sources is short. In this report, the many mechanisms about the generation of negative ions proposed so far are described about negative ion generating mechanism, negative ion source plasma, and negative ion generation on metal surfaces. As a result, negative ion sources are roughly divided into two schemes, plasma extraction and secondary ion extraction, and the former is further classified into the PIG ion source and its variation and Duoplasmatron and its variation; while the latter into reflecting and sputtering types. In the second half of the report, the practical negative ion sources of each scheme are described. If the mechanism of negative ion generation will be investigated more in detail and the development will be continued under the unified know-how as negative ion sources in future, the development of negative ion sources with which large current can be obtained for any element is expected. (Wakatsuki, Y.)

  17. Polemic and Descriptive Negations

    DEFF Research Database (Denmark)

    Horslund, Camilla Søballe

    2011-01-01

    as such may be more or less central to the meaning of the utterance. The present paper investigates the role of morphosyntactic and prosodic prominence as well as register and social setting on the interpretation of negations. It seems plausible to expect that if the negation as such is central to the meaning...... of the utterance (as in polemic negations), the negation will be articulated prominently in order to emphasise this importance. Likewise, if the negation is not central to the meaning of the utterance, it should not be articulated prominently. Moreover, it is plausible to expect descriptive negations to be more...... common in certain social context or genres, while polemic negations are more likely to come up in other genres and social settings. Previous studies have shown a relation between articulatory prominence and register, which may further inform the analysis. Hence, the paper investigates how articulatory...

  18. Clinical and socioeconomic factors associated with negative pediatric appendicitis.

    Science.gov (United States)

    Dubrovsky, Genia; Rouch, Josh; Huynh, Nhan; Friedlander, Scott; Lu, Yang; Lee, Steven L

    2017-10-01

    Misdiagnosing appendicitis may lead to unnecessary surgery. The study evaluates the risk factors for negative appendectomies, as well as the clinical and socioeconomic consequences of negative appendectomy across three states. Data were obtained from the California, New York, and Florida State Inpatient Databases 2005-2011. Patients (<18 years) who underwent nonincidental appendectomies (n = 156,660) were evaluated with hierarchical and multivariate negative binomial regression analyses on outcomes including hospital cost, length of stay (LOS), and associated morbidity. From 2005 to 2011, there was a decrease in the rate of negative appendicitis and perforated appendicitis, whereas the rate of true acute nonperforated appendicitis increased. Whites, females, and privately insured patients were associated with higher negative appendicitis rates, whereas those at an increased risk for perforated appendicitis were African-Americans, males, and those with public or no insurance. Compared to patients with acute nonperforated appendicitis, those with negative appendicitis have significantly higher morbidity (2.5% versus 1.3%), longer LOS (3.4 versus 1.8 d), and greater hospital costs averaged over time ($6926 versus $6492 per patient). Despite a low incidence, negative appendicitis is associated with greater morbidity, longer LOS, and higher cost than acute nonperforated appendicitis. Certain subpopulations are at higher risk for undergoing surgery for negative appendicitis, whereas others are at greater risk for presenting with perforated appendicitis. Further research is needed to understand what drives such disparities and to inform efforts to improve quality of hospital care across all groups of patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Feasibility analysis in the expansion proposal of the nuclear power plant Laguna Verde: application of real options, binomial model; Analisis de viabilidad en la propuesta de expansion de la central nucleoelectrica Laguna Verde: aplicacion de opciones reales, modelo binomial

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez I, S.; Ortiz C, E.; Chavez M, C., E-mail: lunitza@gmail.com [UNAM, Facultad de Ingenieria, Circuito Interior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2011-11-15

    At the present time, is an unquestionable fact that the nuclear electrical energy is a topic of vital importance, no more because eliminates the dependence of the hydrocarbons and is friendly with the environment, but because is also a sure and reliable energy source, and represents a viable alternative before the claims in the growing demand of electricity in Mexico. Before this panorama, was intended several scenarios to elevate the capacity of electric generation of nuclear origin with a variable participation. One of the contemplated scenarios is represented by the expansion project of the nuclear power plant Laguna Verde through the addition of a third reactor that serves as detonator of an integral program that proposes the installation of more nuclear reactors in the country. Before this possible scenario, the Federal Commission of Electricity like responsible organism of supplying energy to the population should have tools that offer it the flexibility to be adapted to the possible changes that will be presented along the project and also gives a value to the risk to future. The methodology denominated Real Options, Binomial model was proposed as an evaluation tool that allows to quantify the value of the expansion proposal, demonstrating the feasibility of the project through a periodic visualization of their evolution, all with the objective of supplying a financial analysis that serves as base and justification before the evident apogee of the nuclear energy that will be presented in future years. (Author)

  20. Negative Ion Density Fronts

    International Nuclear Information System (INIS)

    Igor Kaganovich

    2000-01-01

    Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas

  1. Overcoming the initial investment hurdle for advanced biofuels. An analysis of biofuel-related risks and their impact on project financing. Report of ELOBIO subtask 7

    International Nuclear Information System (INIS)

    Bole, T.; Londo, M.; Van Stralen, J.; Uslu, A.

    2010-04-01

    The ELOBIO research project aims to develop policies that will help achieve a higher share of biofuels in total transport fuel in a low-disturbing and sustainable way. Workpackage 7 of the ELOBIO project aims at addressing the objective of providing a reliable estimate of the potential and costs of biofuels, given the application of low-disturbing policy measures. More specifically, we seek to evaluate the impact of these biofuel policy measures on the investment climate for second-generation technologies. To this end, we try to answer several sub-questions in a following logical sequence: (1) What are the different factors that contribute to investment risk in biofuels and what are their relative contributions to overall biofuel project risk as perceived by finance providers?; (2) How do these risks translate into cost of capital for different biofuel technologies?; (3) How does cost of capital influence market penetration rates for the different technologies?; and (4) What is the best policy (or policy mix) to overcome the initial investment hurdle for advanced biofuels, thus lowering their cost of capital and achieve wider market deployment?.

  2. Feasibility analysis in the expansion proposal of the nuclear power plant Laguna Verde: application of real options, binomial model

    International Nuclear Information System (INIS)

    Hernandez I, S.; Ortiz C, E.; Chavez M, C.

    2011-11-01

    At the present time, is an unquestionable fact that the nuclear electrical energy is a topic of vital importance, no more because eliminates the dependence of the hydrocarbons and is friendly with the environment, but because is also a sure and reliable energy source, and represents a viable alternative before the claims in the growing demand of electricity in Mexico. Before this panorama, was intended several scenarios to elevate the capacity of electric generation of nuclear origin with a variable participation. One of the contemplated scenarios is represented by the expansion project of the nuclear power plant Laguna Verde through the addition of a third reactor that serves as detonator of an integral program that proposes the installation of more nuclear reactors in the country. Before this possible scenario, the Federal Commission of Electricity like responsible organism of supplying energy to the population should have tools that offer it the flexibility to be adapted to the possible changes that will be presented along the project and also gives a value to the risk to future. The methodology denominated Real Options, Binomial model was proposed as an evaluation tool that allows to quantify the value of the expansion proposal, demonstrating the feasibility of the project through a periodic visualization of their evolution, all with the objective of supplying a financial analysis that serves as base and justification before the evident apogee of the nuclear energy that will be presented in future years. (Author)

  3. Using beta-binomial regression for high-precision differential methylation analysis in multifactor whole-genome bisulfite sequencing experiments

    Science.gov (United States)

    2014-01-01

    Background Whole-genome bisulfite sequencing currently provides the highest-precision view of the epigenome, with quantitative information about populations of cells down to single nucleotide resolution. Several studies have demonstrated the value of this precision: meaningful features that correlate strongly with biological functions can be found associated with only a few CpG sites. Understanding the role of DNA methylation, and more broadly the role of DNA accessibility, requires that methylation differences between populations of cells are identified with extreme precision and in complex experimental designs. Results In this work we investigated the use of beta-binomial regression as a general approach for modeling whole-genome bisulfite data to identify differentially methylated sites and genomic intervals. Conclusions The regression-based analysis can handle medium- and large-scale experiments where it becomes critical to accurately model variation in methylation levels between replicates and account for influence of various experimental factors like cell types or batch effects. PMID:24962134

  4. Inference for binomial probability based on dependent Bernoulli random variables with applications to meta‐analysis and group level studies

    Science.gov (United States)

    Bakbergenuly, Ilyas; Morgenthaler, Stephan

    2016-01-01

    We study bias arising as a result of nonlinear transformations of random variables in random or mixed effects models and its effect on inference in group‐level studies or in meta‐analysis. The findings are illustrated on the example of overdispersed binomial distributions, where we demonstrate considerable biases arising from standard log‐odds and arcsine transformations of the estimated probability p^, both for single‐group studies and in combining results from several groups or studies in meta‐analysis. Our simulations confirm that these biases are linear in ρ, for small values of ρ, the intracluster correlation coefficient. These biases do not depend on the sample sizes or the number of studies K in a meta‐analysis and result in abysmal coverage of the combined effect for large K. We also propose bias‐correction for the arcsine transformation. Our simulations demonstrate that this bias‐correction works well for small values of the intraclass correlation. The methods are applied to two examples of meta‐analyses of prevalence. PMID:27192062

  5. Inference for binomial probability based on dependent Bernoulli random variables with applications to meta-analysis and group level studies.

    Science.gov (United States)

    Bakbergenuly, Ilyas; Kulinskaya, Elena; Morgenthaler, Stephan

    2016-07-01

    We study bias arising as a result of nonlinear transformations of random variables in random or mixed effects models and its effect on inference in group-level studies or in meta-analysis. The findings are illustrated on the example of overdispersed binomial distributions, where we demonstrate considerable biases arising from standard log-odds and arcsine transformations of the estimated probability p̂, both for single-group studies and in combining results from several groups or studies in meta-analysis. Our simulations confirm that these biases are linear in ρ, for small values of ρ, the intracluster correlation coefficient. These biases do not depend on the sample sizes or the number of studies K in a meta-analysis and result in abysmal coverage of the combined effect for large K. We also propose bias-correction for the arcsine transformation. Our simulations demonstrate that this bias-correction works well for small values of the intraclass correlation. The methods are applied to two examples of meta-analyses of prevalence. © 2016 The Authors. Biometrical Journal Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  6. Response of selected binomial coefficients to varying degrees of matrix sparseness and to matrices with known data interrelationships

    Science.gov (United States)

    Archer, A.W.; Maples, C.G.

    1989-01-01

    Numerous departures from ideal relationships are revealed by Monte Carlo simulations of widely accepted binomial coefficients. For example, simulations incorporating varying levels of matrix sparseness (presence of zeros indicating lack of data) and computation of expected values reveal that not only are all common coefficients influenced by zero data, but also that some coefficients do not discriminate between sparse or dense matrices (few zero data). Such coefficients computationally merge mutually shared and mutually absent information and do not exploit all the information incorporated within the standard 2 ?? 2 contingency table; therefore, the commonly used formulae for such coefficients are more complicated than the actual range of values produced. Other coefficients do differentiate between mutual presences and absences; however, a number of these coefficients do not demonstrate a linear relationship to matrix sparseness. Finally, simulations using nonrandom matrices with known degrees of row-by-row similarities signify that several coefficients either do not display a reasonable range of values or are nonlinear with respect to known relationships within the data. Analyses with nonrandom matrices yield clues as to the utility of certain coefficients for specific applications. For example, coefficients such as Jaccard, Dice, and Baroni-Urbani and Buser are useful if correction of sparseness is desired, whereas the Russell-Rao coefficient is useful when sparseness correction is not desired. ?? 1989 International Association for Mathematical Geology.

  7. A new phase modulated binomial-like selective-inversion sequence for solvent signal suppression in NMR.

    Science.gov (United States)

    Chen, Johnny; Zheng, Gang; Price, William S

    2017-02-01

    A new 8-pulse Phase Modulated binomial-like selective inversion pulse sequence, dubbed '8PM', was developed by optimizing the nutation and phase angles of the constituent radio-frequency pulses so that the inversion profile resembled a target profile. Suppression profiles were obtained for both the 8PM and W5 based excitation sculpting sequences with equal inter-pulse delays. Significant distortions were observed in both profiles because of the offset effect of the radio frequency pulses. These distortions were successfully reduced by adjusting the inter-pulse delays. With adjusted inter-pulse delays, the 8PM and W5 based excitation sculpting sequences were tested on an aqueous lysozyme solution. The 8 PM based sequence provided higher suppression selectivity than the W5 based sequence. Two-dimensional nuclear Overhauser effect spectroscopy experiments were also performed on the lysozyme sample with 8PM and W5 based water signal suppression. The 8PM based suppression provided a spectrum with significantly increased (~ doubled) cross-peak intensity around the suppressed water resonance compared to the W5 based suppression. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Negative thermal expansion materials

    International Nuclear Information System (INIS)

    Evans, J.S.O.

    1997-01-01

    The recent discovery of negative thermal expansion over an unprecedented temperature range in ZrW 2 O 8 (which contracts continuously on warming from below 2 K to above 1000 K) has stimulated considerable interest in this unusual phenomenon. Negative and low thermal expansion materials have a number of important potential uses in ceramic, optical and electronic applications. We have now found negative thermal expansion in a large new family of materials with the general formula A 2 (MO 4 ) 3 . Chemical substitution dramatically influences the thermal expansion properties of these materials allowing the production of ceramics with negative, positive or zero coefficients of thermal expansion, with the potential to control other important materials properties such as refractive index and dielectric constant. The mechanism of negative thermal expansion and the phase transitions exhibited by this important new class of low-expansion materials will be discussed. (orig.)

  9. Asimetría y curtosis en el modelo binomial para valorar opciones reales: caso de aplicación para empresas de base tecnológica

    Directory of Open Access Journals (Sweden)

    Gastón Silverio Milanesi

    2013-07-01

    Full Text Available El trabajo propone un modelo de valoración de opciones reales con base en el modelo binomial utilizando la transformación de Edgeworth (Rubinstein, 1998 para incorporar momentos estocásticos de orden supe- rior, especialmente para ciertos tipos de organizaciones, como empresas de base tecnológica, donde no se dispone de cartera de activos financieros gemelos, comparables de mercado y procesos estocásticos no gaussianos. Primero, se presenta el desarrollo formal del modelo, luego su aplicación sobre la valuación de spin-off tecnológico universitario, sensibilizando asimetría-curtosis y exponiendo el impacto en el valor del proyecto. Finalmente, se concluye sobre limitaciones y ventajas de la propuesta de valoración que resume la simplicidad del modelo binomial e incorporando momentos de orden superior en subyacentes con pro- cesos no normales.

  10. Asimetría y curtosis en el modelo binomial para valorar opciones reales: caso de aplicación para empresas de base tecnológica

    Directory of Open Access Journals (Sweden)

    Gastón Silverio Milanesi

    2013-01-01

    Full Text Available El trabajo propone un modelo de valoración de opciones reales con base en el modelo binomial utilizando la transformación de Edgeworth (Rubinstein, 1998 para incorporar momentos estocásticos de orden superior, especialmente para ciertos tipos de organizaciones, como empresas de base tecnológica, donde no se dispone de cartera de activos financieros gemelos, comparables de mercado y procesos estocásticos no gaussianos. Primero, se presenta el desarrollo formal del modelo, luego su aplicación sobre la valuación de spin-off tecnológico universitario, sensibilizando asimetría-curtosis y exponiendo el impacto en el valor del proyecto. Finalmente, se concluye sobre limitaciones y ventajas de la propuesta de valoración que resume la simplicidad del modelo binomial e incorporando momentos de orden superior en subyacentes con procesos no normales.

  11. Negative thermal expansion

    International Nuclear Information System (INIS)

    Barrera, G D; Bruno, J A O; Barron, T H K; Allan, N L

    2005-01-01

    There has been substantial renewed interest in negative thermal expansion following the discovery that cubic ZrW 2 O 8 contracts over a temperature range in excess of 1000 K. Substances of many different kinds show negative thermal expansion, especially at low temperatures. In this article we review the underlying thermodynamics, emphasizing the roles of thermal stress and elasticity. We also discuss vibrational and non-vibrational mechanisms operating on the atomic scale that are responsible for negative expansion, both isotropic and anisotropic, in a wide range of materials. (topical review)

  12. Isotropic Single Negative Metamaterials

    Directory of Open Access Journals (Sweden)

    P. Protiva

    2008-09-01

    Full Text Available This paper presents the application of simple, and therefore cheap, planar resonators for building 3D isotropic metamaterials. These resonators are: a broadside-coupled split ring resonator with a magnetic response providing negative permeability; an electric dipole terminated by a loop inductor together with a double H-shaped resonator with an electric response providing negative permittivity. Two kinds of 3D isotropic single negative metamaterials are reported. The first material consists of unit cells in the form of a cube bearing on its faces six equal planar resonators with tetrahedral symmetry. In the second material, the planar resonators boxed into spherical plastic shells and randomly distributed in a hosting material compose a real 3D volumetric metamaterial with an isotropic response. In both cases the metamaterial shows negative permittivity or permeability, according to the type of resonators that are used. The experiments prove the isotropic behavior of the cells and of the metamaterial specimens.

  13. [The binomial symptom index for the evaluation of temporal association between cardiorespiratory symptoms and gastroesophageal reflux in neonates].

    Science.gov (United States)

    Barriga-Rivera, Alejandro; Moya, María José; Lopez-Alonso, Manuel

    2016-11-01

    The evaluation of symptom association between gastroesophageal reflux and cardiorespiratory events in preterm infants remains unclear. This paper describes a conservative approach to decision-making of anti-reflux surgery through symptom association analysis. Forty-three neonates with potentially reflux-related cardiorespiratory symptoms underwent synchronized esophageal impedance-pH and cardiorespiratory monitoring. Three indices were considered to evaluate symptom association, the symptom index (SI), the symptom sensitivity index (SSI) and the symptom association probability (SAP). A conservative strategy was adopted regarding the decision of anti-reflux surgery, and therefore, patients were scheduled for laparoscopic Nissen fundoplication if the three indices showed a positive assessment of symptom association. Retrospectively, these indices and the binomial symptom index (BSI) were contrasted against the decision of anti-reflux surgery using different windows of association. Thirteen patients showed positive symptom association but only two underwent anti-reflux surgery. The SI and the SSI showed an increasing trend with the width of the window of association. The SAP was affected randomly by slightly altering the windowing parameters. The BSI showed the best performance with the two-minute window (κ =0.78) CONCLUSIONS: The pathology under study is known to improve with maturity. However, the severity of cardiorespiratory symptoms may threaten the neonate's life and therefore, in some occasions, invasive treatments must be considered to protect life. The BSI provides a good prediction of a combination of positive SI, SSI and SAP, which may improve clinical decisions. However, further clinical studies are required to prove the BSI as an optimal predictor of clinical outcomes. Copyright © 2015 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  14. Microbial inactivation and shelf life comparison of 'cold' hurdle processing with pulsed electric fields and microfiltration, and conventional thermal pasteurisation in skim milk.

    Science.gov (United States)

    Walkling-Ribeiro, M; Rodríguez-González, O; Jayaram, S; Griffiths, M W

    2011-01-05

    Thermal pasteurisation (TP) is the established food technology for commercial processing of milk. However, degradation of valuable nutrients in milk and its sensory characteristics occurs during TP due to substantial heat exposure. Pulsed electric fields (PEF) and microfiltration (MF) both represent emerging food processing technologies allowing gentle milk preservation at lower temperatures and shorter treatment times for similar, or better, microbial inactivation and shelf stability when applied in a hurdle approach compared to TP. Incubated raw milk was used as an inoculum for the enrichment of skim milk with native microorganisms before PEF, MF, and TP processing. Inoculated milk was PEF-processed at electric field strengths between 16 and 42 kV/cm for treatment times from 612 to 2105 μs; accounting for energy densities between 407 and 815 kJ/L, while MF was applied with a transmembrane flux of 660 L/h m². Milk was TP-treated at 75°C for 24 s. Comparing PEF, MF, and TP for the reduction of the native microbial load in milk led to a 4.6 log₁₀ CFU/mL reduction in count for TP, which was similar to 3.7 log₁₀ CFU/mL obtained by MF (P≥0.05), and more effective than the 2.5 log₁₀ CFU/mL inactivation achieved by PEF inactivation (at 815 kJ/L (Pfield strength, shorter treatment time, larger energy density, and rising temperature the efficacy of PEF/MF increased contrary to MF/PEF. Thus, PEF/MF represents a potential alternative for 'cold' pasteurisation of milk with improved quality. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. NEGATION AFFIXES IN ENGLISH

    Directory of Open Access Journals (Sweden)

    Dedy Subandowo -

    2017-02-01

    Full Text Available Abstract: This research entitled "Negation Affixes in English". This study is aimed to describe the various negation affixes in English, morphological process, morphophonemic and meaning. The research data were taken from various sources of English grammar book, morphology, research journal and the book which relatees to the research. English grammar books used in this study are written by Otto Jesperson, Marcella Frank, Greenbaum and Geoffrey Leech.  The method used in this research is the descriptive-qualitative method. While the data collection techniques are performed by using jot-down method. And the results of analysis are presented in tabular form and descriptive method. The result of the research shows that English has six types of negative affixes which are categorized by the intensity of its appearance, such as dis-, in-, non-, un-, anti- and -less. Based on the function, negation affixes are divided into several categories such as adjectives, nouns, verbs, and adverbs. The morphophonemic affix in- has four allomorphs, they are in-, im-, il- and ir- . While the analysis revealed that negation affixes have some basic meanings, such as ‘not’, ‘without’, and ‘anti’.

  16. Nedtrykt af negative nyheder

    DEFF Research Database (Denmark)

    Skovsgaard, Morten; Søberg, Pernille Frantz

    2016-01-01

    I adskillige år er det blevet debatteret, hvorvidt nyhedernes negative fokus har konsekvenser for borgerne, og om det i sid-ste ende får flere til at vende ryggen til nyhederne. Vores viden om effekterne af positive og negative nyheder er dog begrænset, og derfor undersøges det i denne artikel......, hvordan henholdsvis positive og negative tv-nyheder påvirker seernes humør, hukom-melse af information fra indslaget og lyst til at se yderligere tv-nyheder. Det gør vi i et survey-eksperiment (N=204), hvor tre grupper så enten et originalt indslag eller det samme indslag klippet med henholdsvis et...

  17. On Various Negative Translations

    Directory of Open Access Journals (Sweden)

    Gilda Ferreira

    2011-01-01

    Full Text Available Several proof translations of classical mathematics into intuitionistic mathematics have been proposed in the literature over the past century. These are normally referred to as negative translations or double-negation translations. Among those, the most commonly cited are translations due to Kolmogorov, Godel, Gentzen, Kuroda and Krivine (in chronological order. In this paper we propose a framework for explaining how these different translations are related to each other. More precisely, we define a notion of a (modular simplification starting from Kolmogorov translation, which leads to a partial order between different negative translations. In this derived ordering, Kuroda and Krivine are minimal elements. Two new minimal translations are introduced, with Godel and Gentzen translations sitting in between Kolmogorov and one of these new translations.

  18. Negative ion sourcery

    International Nuclear Information System (INIS)

    Os, C.F.A. van.

    1989-01-01

    The work described in this thesis is involved by current research programs in the field of nuclear-fusion. A brief introduction to fusion is given, anticipated problems related to current drive of the fusion plasma are pinpointed and probable suggestions to overcome these problems are described. One probable means for current drive is highlighted; Neutral Beam Injection (NBI). This is based on injecting a 1 MeV neutral hydrogen or deuterium beam into a fusion plasma. Negative ions are needed as primary particles because they can easily be neutralized at 1 MeV. The two current schemes for production of negative ions are described, volume production and negative surface ionization. The latter method is extensively studied in this thesis. (author). 171 refs.; 55 figs.; 7 tabs

  19. Depressionens negative spiral

    DEFF Research Database (Denmark)

    Munk, Karen

    2006-01-01

    Artiklen formidler resultater fra en longitudinel undersøgelse af det selvforstærkende, negative samspil imellem udvikling og vedligeholdelse af alderdomsdepression via primære miljøbelastninger og via  den deprimerede ældre som belastning for miljøet, som i sin tur "svarer negativt" på lidelsen og...

  20. Quantum logic without negation

    Energy Technology Data Exchange (ETDEWEB)

    Zapatrin, R.R. (Dept. of Mathematics, SPb UEF, St. Petersburg (Russian Federation))

    1994-05-01

    The algebraic tools based on generating semigroups are suggested to describe property lattices possessing the relation of exclusivity rather than the operation of negation. The reduction to standard situation of orthocomplemented and orthomodular lattices is described. As an example of non-orthocomplementable property lattice that of a hypothetical ''topologymeter'' is studied. (orig.)

  1. The Negative Repetition Effect

    Science.gov (United States)

    Mulligan, Neil W.; Peterson, Daniel J.

    2013-01-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising "negative repetition effect," in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and…

  2. Using a Simple Binomial Model to Assess Improvement in Predictive Capability: Sequential Bayesian Inference, Hypothesis Testing, and Power Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sigeti, David E. [Los Alamos National Laboratory; Pelak, Robert A. [Los Alamos National Laboratory

    2012-09-11

    We present a Bayesian statistical methodology for identifying improvement in predictive simulations, including an analysis of the number of (presumably expensive) simulations that will need to be made in order to establish with a given level of confidence that an improvement has been observed. Our analysis assumes the ability to predict (or postdict) the same experiments with legacy and new simulation codes and uses a simple binomial model for the probability, {theta}, that, in an experiment chosen at random, the new code will provide a better prediction than the old. This model makes it possible to do statistical analysis with an absolute minimum of assumptions about the statistics of the quantities involved, at the price of discarding some potentially important information in the data. In particular, the analysis depends only on whether or not the new code predicts better than the old in any given experiment, and not on the magnitude of the improvement. We show how the posterior distribution for {theta} may be used, in a kind of Bayesian hypothesis testing, both to decide if an improvement has been observed and to quantify our confidence in that decision. We quantify the predictive probability that should be assigned, prior to taking any data, to the possibility of achieving a given level of confidence, as a function of sample size. We show how this predictive probability depends on the true value of {theta} and, in particular, how there will always be a region around {theta} = 1/2 where it is highly improbable that we will be able to identify an improvement in predictive capability, although the width of this region will shrink to zero as the sample size goes to infinity. We show how the posterior standard deviation may be used, as a kind of 'plan B metric' in the case that the analysis shows that {theta} is close to 1/2 and argue that such a plan B should generally be part of hypothesis testing. All the analysis presented in the paper is done with a

  3. Hurdles for a Broader Use of 211At and for the Synthesis of 211At-Labelled Radiopharmaceuticals at High Activities for Clinical Use

    International Nuclear Information System (INIS)

    Pozzi, O.R.; Zalutsky, M.R.

    2013-01-01

    One of the key impediments to the use of 211 At is the very well known deleterious effect of high radiation fields caused by its alpha particles on the synthesis of 211 At-labelled radiopharmaceuticals. This is problematic because radiolysis-mediated effects can produce diminishing efficiency of electrophilic astatination reactions due to increasing deposition of radiation dose with increasing activities and with the passage of the time. Astatine-211 has chemical properties that permit complex labelling strategies and a longer half-life than 2 13 Bi that makes it more suitable when the targeting molecule does not gain immediate access to the tumour cells. The first clinical evaluation was published in 2001 [2] in patients with brain tumour. Although this study circumvents many of the challenges to entering clinical studies with 211 At and many obstacles had to be surmounted before clinical studies could be initiated, several problems were encountered in maintaining efficient labelling with escalating radiation dose of α-particle even with fresh 211 At elution [3]. Astatine-211 also has an additional hurdle to overcome before to its clinical application in labelled radiopharmaceuticals related with its production and distribution. Among the potential group of promising α- emitter it is the only one produced by cyclotrons, but due to the scarcity of cyclotrons equipped with 25−30 MeV α-particle beams, it will of necessity be utilized in distant locations from the site of production. It presents a major chemical challenge because the diminishing efficiency of electrophilic astatination reactions with the passage of the time is well known, a problem likely related to the radiolysis produced by the high LET (linear energy transfer) meaning that large amounts of energy are deposited in a highly localized manner. This problem has been most comprehensively investigated to understand and evaluate the role of the radiolysis effects of astatine alpha particles in the

  4. Headspace oxygen as a hurdle to improve the safety of in-pack pasteurized chilled food during storage at different temperatures.

    Science.gov (United States)

    Muñoz, Nydia; Bhunia, Kanishka; Zhang, Hongchao; Barbosa-Cánovas, Gustavo V; Tang, Juming; Sablani, Shyam

    2017-07-17

    This study investigated the use of headspace oxygen in a model food system to prevent the growth of anaerobic pathogenic bacteria in in-pack pasteurized food at various storage temperatures. Three model food formulations prepared with tryptic soy broth and three agar concentrations (0.1, 0.4 and 1.0%) were sealed without removing the air from the package in high oxygen barrier pouches (OTR=0.3cm 3 /m 2 ·day·atm). Important properties influencing bacterial growth, including pH and water activity (a w ) were determined. The oxygen sorption kinetics of each model food were obtained at three different storage temperatures (8, 12, and 20°C) using an OxySense Gen III 300 system. An analytical solution of Fick's second law was used to determine the O 2 diffusion coefficient. Growth challenge studies at 12 and 20°C were conducted at three selected locations (top, center and bottom layers) in model foods containing 1% agar. Model foods were inoculated with Clostridium sporogenes PA 3679 (300spores/mL), and were classified as low-acid (pH>4.5, a w >0.85). When the storage temperature decreased from 20 to 8°C, the oxygen diffusion decreased from 0.82×10 -9 m 2 /s to 0.68×10 -9 m 2 /s. As the agar concentration was increased from 0.1 to 1.0%, the effective oxygen permeability decreased significantly (p=0.007) from 0.88×10 -9 m 2 /s to 0.65×10 -9 m 2 /s. When the inoculated model foods were stored at 12°C for 14days, C. sporogenes PA 3679 was unable to grow. As the storage temperature was increased to 20°C, significant bacterial growth was observed with storage time (pfood did not influence the growth distribution of C. sporogenes PA 3679. These results demonstrate that oxygen diffusion from the pouch headspace was primarily limited to the food surface. Findings suggest that the air/oxygen present in the package headspace may not be considered as a food safety hurdle in the production of pasteurized packaged food. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Entanglement and Other Nonclassical Properties of Two Two-Level Atoms Interacting with a Two-Mode Binomial Field: Constant and Intensity-Dependent Coupling Regimes

    International Nuclear Information System (INIS)

    Tavassoly, M.K.; Hekmatara, H.

    2015-01-01

    In this paper, we consider the interaction between two two-level atoms and a two-mode binomial field with a general intensity-dependent coupling regime. The outlined dynamical problem has explicit analytical solution, by which we can evaluate a few of its physical features of interest. To achieve the purpose of the paper, after choosing a particular nonlinearity function, we investigate the quantum statistics, atomic population inversion and at last the linear entropy of the atom-field system which is a good measure for the degree of entanglement. In detail, the effects of binomial field parameters, in addition to different initial atomic states on the temporal behavior of the mentioned quantities have been analyzed. The results show that, the values of binomial field parameters and the initial state of the two atoms influence on the nonclassical effects in the obtained states through which one can tune the nonclassicality criteria appropriately. Setting intensity-dependent coupling function equal to 1 reduces the results to the constant coupling case. By comparing the latter case with the nonlinear regime, we will observe that the nonlinearity disappears the pattern of collapse-revival phenomenon in the evolution of Mandel parameter and population inversion (which can be seen in the linear case with constant coupling), however, more typical collapse-revivals will be appeared for the cross-correlation function in the nonlinear case. Finally, in both linear and nonlinear regime, the entropy remains less than (but close to) 0.5. In other words the particular chosen nonlinearity does not critically affect on the entropy of the system. (paper)

  6. Estimating negative likelihood ratio confidence when test sensitivity is 100%: A bootstrapping approach.

    Science.gov (United States)

    Marill, Keith A; Chang, Yuchiao; Wong, Kim F; Friedman, Ari B

    2017-08-01

    Objectives Assessing high-sensitivity tests for mortal illness is crucial in emergency and critical care medicine. Estimating the 95% confidence interval (CI) of the likelihood ratio (LR) can be challenging when sample sensitivity is 100%. We aimed to develop, compare, and automate a bootstrapping method to estimate the negative LR CI when sample sensitivity is 100%. Methods The lowest population sensitivity that is most likely to yield sample sensitivity 100% is located using the binomial distribution. Random binomial samples generated using this population sensitivity are then used in the LR bootstrap. A free R program, "bootLR," automates the process. Extensive simulations were performed to determine how often the LR bootstrap and comparator method 95% CIs cover the true population negative LR value. Finally, the 95% CI was compared for theoretical sample sizes and sensitivities approaching and including 100% using: (1) a technique of individual extremes, (2) SAS software based on the technique of Gart and Nam, (3) the Score CI (as implemented in the StatXact, SAS, and R PropCI package), and (4) the bootstrapping technique. Results The bootstrapping approach demonstrates appropriate coverage of the nominal 95% CI over a spectrum of populations and sample sizes. Considering a study of sample size 200 with 100 patients with disease, and specificity 60%, the lowest population sensitivity with median sample sensitivity 100% is 99.31%. When all 100 patients with disease test positive, the negative LR 95% CIs are: individual extremes technique (0,0.073), StatXact (0,0.064), SAS Score method (0,0.057), R PropCI (0,0.062), and bootstrap (0,0.048). Similar trends were observed for other sample sizes. Conclusions When study samples demonstrate 100% sensitivity, available methods may yield inappropriately wide negative LR CIs. An alternative bootstrapping approach and accompanying free open-source R package were developed to yield realistic estimates easily. This

  7. Negative leave balances

    CERN Multimedia

    Human Resources Department

    2005-01-01

    Members of the personnel entitled to annual leave and, where appropriate, saved leave and/or compensatory leave are requested to take note of the new arrangements described below, which were recommended by the Standing Concertation Committee (SCC) at its meeting on 1Â September 2005 and subsequently approved by the Director-General. The changes do not apply to members of the personnel participating in the Progressive Retirement Programme (PRP) or the Part-time Work as a pre-retirement measure, for whom the specific provisions communicated at the time of joining will continue to apply. Â Negative balances in annual leave, saved leave and/or compensatory leave accounts at the end of the leave year (30th September) and on the date on which bonuses are credited to the saved leave account (31st December): Where members of the personnel have a leave account with a negative balance on 30Â September and/or 31Â December, leave will automatically be transferred from one account to another on the relevant dates i...

  8. Negative leave balances

    CERN Multimedia

    Human Resources Department

    2005-01-01

    Members of the personnel entitled to annual leave and, where appropriate, saved leave and/or compensatory leave are requested to take note of the new arrangements described below, which were recommended by the Standing Concertation Committee (SCC) at its meeting on 1 September 2005 and subsequently approved by the Director-General. The changes do not apply to members of the personnel participating in the Progressive Retirement Programme (PRP) or the Part-time Work as a pre-retirement measure, for whom the specific provisions communicated at the time of joining will continue to apply.  Negative balances in annual leave, saved leave and/or compensatory leave accounts at the end of the leave year (30th September) and on the date on which bonuses are credited to the saved leave account (31st December): Where members of the personnel have a leave account with a negative balance on 30 September and/or 31 December, leave will automatically be transferred from one account to another on the relevant dates in or...

  9. A binomial truncation function proposed for the second-moment approximation of tight-binding potential and application in the ternary Ni-Hf-Ti system

    International Nuclear Information System (INIS)

    Li, J H; Dai, X D; Wang, T L; Liu, B X

    2007-01-01

    We propose a two-parameter binomial truncation function for the second-moment approximation of the tight-binding (TB-SMA) interatomic potential and illustrate in detail the procedure of constructing the potentials for binary and ternary transition metal systems. For the ternary Ni-Hf-Ti system, the lattice constants, cohesion energies, elastic constants and bulk moduli of six binary compounds, i.e. L1 2 Ni 3 Hf, NiHf 3 , Ni 3 Ti, NiTi 3 , Hf 3 Ti and HfTi 3 , are firstly acquired by ab initio calculations and then employed to derive the binomial-truncated TB-SMA Ni-Hf-Ti potential. Applying the ab initio derived Ni-Hf-Ti potential, the lattice constants, cohesive energy, elastic constants and bulk moduli of another six binary compounds, i.e. D0 3 NiHf 3 , NiTi 3 HfTi 3 , and B2 NiHf, NiTi, HfTi, and two ternary compounds, i.e. C1 b NiHfTi, L2 1 Ni 2 HfTi, are calculated, respectively. It is found that, for the eight binary compounds studied, the calculated lattice constants and cohesion energies are in excellent agreement with those directly acquired from ab initio calculations and that the elastic constants and bulk moduli calculated from the potential are also qualitatively consistent with the results from ab initio calculations

  10. A New Extension of the Binomial Error Model for Responses to Items of Varying Difficulty in Educational Testing and Attitude Surveys.

    Directory of Open Access Journals (Sweden)

    James A Wiley

    Full Text Available We put forward a new item response model which is an extension of the binomial error model first introduced by Keats and Lord. Like the binomial error model, the basic latent variable can be interpreted as a probability of responding in a certain way to an arbitrarily specified item. For a set of dichotomous items, this model gives predictions that are similar to other single parameter IRT models (such as the Rasch model but has certain advantages in more complex cases. The first is that in specifying a flexible two-parameter Beta distribution for the latent variable, it is easy to formulate models for randomized experiments in which there is no reason to believe that either the latent variable or its distribution vary over randomly composed experimental groups. Second, the elementary response function is such that extensions to more complex cases (e.g., polychotomous responses, unfolding scales are straightforward. Third, the probability metric of the latent trait allows tractable extensions to cover a wide variety of stochastic response processes.

  11. [Negative pressure therapy: NPT].

    Science.gov (United States)

    Maillard, H

    2015-01-01

    Negative pressure therapy or treatment (NPT) is used very frequently in hospitals in both surgical and medical departments. NPT consists of maintaining the wound surface at a pressure below ambient atmospheric pressure by means of a specially designed dressing attached to a depressurisation device as well as a system to drain exudate. NPT has been shown to be beneficial in increasing blood flow, thanks to feedback resulting from the decreased oxygen pressure, angiogenesis and reduction of the wound surface area. The French Health Authority (HAS) has issued recommendations for good use in a specific and limited series of applications. NPT may be used in post-traumatic or post-surgical wounds, burns, and in chronic wounds, such as bedsores and ulcers. It is also effective as an adjuvant treatment for infected wounds. In recent years, various different NPT devices have become commercially available. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  12. Coagulase-Negative Staphylococci

    Science.gov (United States)

    Heilmann, Christine; Peters, Georg

    2014-01-01

    SUMMARY The definition of the heterogeneous group of coagulase-negative staphylococci (CoNS) is still based on diagnostic procedures that fulfill the clinical need to differentiate between Staphylococcus aureus and those staphylococci classified historically as being less or nonpathogenic. Due to patient- and procedure-related changes, CoNS now represent one of the major nosocomial pathogens, with S. epidermidis and S. haemolyticus being the most significant species. They account substantially for foreign body-related infections and infections in preterm newborns. While S. saprophyticus has been associated with acute urethritis, S. lugdunensis has a unique status, in some aspects resembling S. aureus in causing infectious endocarditis. In addition to CoNS found as food-associated saprophytes, many other CoNS species colonize the skin and mucous membranes of humans and animals and are less frequently involved in clinically manifested infections. This blurred gradation in terms of pathogenicity is reflected by species- and strain-specific virulence factors and the development of different host-defending strategies. Clearly, CoNS possess fewer virulence properties than S. aureus, with a respectively different disease spectrum. In this regard, host susceptibility is much more important. Therapeutically, CoNS are challenging due to the large proportion of methicillin-resistant strains and increasing numbers of isolates with less susceptibility to glycopeptides. PMID:25278577

  13. Microdosimetry of negative pions

    International Nuclear Information System (INIS)

    Amols, H.I.; Dicello, J.F.; Lane, T.F.

    1976-01-01

    The radiation quality of negative and positive pions of initial momentum 168MeV/c has been determined at eight different depths in a liquid phantom. The measurements were made with a 2.5cm diameter spherical proportional counter with Shonka A-150 neutron tissue equivalent plastic walls. The gas pressure in the sensitive volume was chosen to stimulate a diameter of 2μm in unit density material. Dose distributions as a function of lineal energy change slowly in the entrance and plateau regions with a dose mean lineal energy of 6-8keV/μm. Less than 3% of the dose is delivered in excess of 50keV/μm in this region. In the Bragg peak region the distributions change rapidly as a function of depth with the dose mean lineal energy increasing to 38keV/μm at the peak and to 57keV/μm just beyond the peak. On the basis of these microdosimetric data predictions of RBE and OER have been made with the use of both the theory of dual radiation action and also the delta ray theory of cell survival. The former has been used to predict biological response at low doses and the latter at high doses. A comparison is made between the two theories at intermediate doses. The results of these calculations are not inconsistant with recent biological data

  14. Análisis estadístico para datos de conteo: aplicaciones para el uso de los servicios de salud Statistical analysis for count data: use of healthcare services applications

    Directory of Open Access Journals (Sweden)

    Aarón Salinas-Rodríguez

    2009-10-01

    Full Text Available OBJETIVO: Describir algunos de los modelos estadísticos para el estudio de variables expresadas como un conteo en el contexto del uso de los servicios de salud. MATERIAL Y MÉTODOS: Con base en la Encuesta de Evaluación del Seguro Popular (2005-2006 se calculó el efecto del Seguro Popular sobre el número de consultas externas mediante el uso de los modelos de regresión Poisson, binomial negativo, binomial negativo cero-inflado y Hurdle binomial negativo. Se utilizó el criterio de información de Akaike (AIC para definir el mejor modelo. RESULTADOS: La mejor opción estadística para el análisis del uso de los servicios de salud resultó ser el modelo Hurdle, de acuerdo con sus presuposiciones y el valor del AIC. DISCUSIÓN: La modelación de variables de conteo requiere el empleo de modelos que incluyan una medición de la dispersión. Ante la presencia de exceso de ceros, el modelo Hurdle es una opción apropiada.OBJECTIVE: To describe some of the statistical models for the study of count variables in the context of the use of health services. MATERIAL AND METHODS: We used the Seguro Popular Evaluation Survey to estimate the effect of Seguro Popular on the frequency of use of outpatient health services, using Poisson regression models and negative binomial, zero-inflated negative binomial and the hurdle negative binomial models. We used the Akaike Information Criterion (AIC to define the best model. RESULTS: Results show that the best statistical approach to model the use of health services is the hurdle model, taking into account both the main theoretical assumptions and the statistical results of the AIC. DISCUSSION: The modelling of count data requires the application of statistical models to model data dispersion; in the presence of an excess of zeros, the hurdle model is an appropriate statistical option.

  15. INVESTIGATION OF E-MAIL TRAFFIC BY USING ZERO-INFLATED REGRESSION MODELS

    Directory of Open Access Journals (Sweden)

    Yılmaz KAYA

    2012-06-01

    Full Text Available Based on count data obtained with a value of zero may be greater than anticipated. These types of data sets should be used to analyze by regression methods taking into account zero values. Zero- Inflated Poisson (ZIP, Zero-Inflated negative binomial (ZINB, Poisson Hurdle (PH, negative binomial Hurdle (NBH are more common approaches in modeling more zero value possessing dependent variables than expected. In the present study, the e-mail traffic of Yüzüncü Yıl University in 2009 spring semester was investigated. ZIP and ZINB, PH and NBH regression methods were applied on the data set because more zeros counting (78.9% were found in data set than expected. ZINB and NBH regression considered zero dispersion and overdispersion were found to be more accurate results due to overdispersion and zero dispersion in sending e-mail. ZINB is determined to be best model accordingto Vuong statistics and information criteria.

  16. Meaning of the negative impedance

    Energy Technology Data Exchange (ETDEWEB)

    Conciauro, G.; Puglisi, M.

    1981-06-01

    It is shown that the negative real part of an input impedance does not mean instability of the related circuit. A negative real part of the input impedance means only that the concerned circuit is active.

  17. Meaning of the negative impedance

    International Nuclear Information System (INIS)

    Conciauro, G.; Puglisi, M.

    1981-06-01

    It is shown that the negative real part of an input impedance does not mean instability of the related circuit. A negative real part of the input impedance means only that the concerned circuit is active

  18. Negative index in chiral metamaterials

    OpenAIRE

    Singh, S.; Plum, E.; Menzel, C.; Rockstuhl, C.; Zheludev, N.; Zhang, W.

    2011-01-01

    We demonstrate that planar metamaterial lacking of mirror symmetry shows asymmetric transmission of terahertz waves and bands of positive, negative and zero phase and group velocities indicating a polarization sensitive negative index and slow-light media.

  19. Negative dimensional integrals. Pt. 1

    International Nuclear Information System (INIS)

    Halliday, I.G.; Ricotta, R.M.

    1987-01-01

    We propose a new method of evaluating integrals based on negative dimensional integration. We compute Feynman graphs by considering analytic extensions. Propagators are raised to negative integer powers and integrated over negative integer dimensions. We are left with the problem of computing polynomial integrals and summing finite series. (orig.)

  20. Thermodynamics of negative absolute pressures

    International Nuclear Information System (INIS)

    Lukacs, B.; Martinas, K.

    1984-03-01

    The authors show that the possibility of negative absolute pressure can be incorporated into the axiomatic thermodynamics, analogously to the negative absolute temperature. There are examples for such systems (GUT, QCD) processing negative absolute pressure in such domains where it can be expected from thermodynamical considerations. (author)

  1. Negative chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    Smit, A.L.C.

    1979-01-01

    This thesis describes some aspects of Negative Chemical Ionization (NCI) mass spectrometry. The reasons for the growing interest in NCI are: (i) to extend the basic knowledge of negative ions and their reactions in the gas phase; (ii) to investigate whether or not this knowledge of negative ions can be used successfully to elucidate the structure of molecules by mass spectrometry. (Auth.)

  2. MultiTest V.1.2, a program to binomially combine independent tests and performance comparison with other related methods on proportional data

    Directory of Open Access Journals (Sweden)

    Guégan Jean-François

    2009-12-01

    Full Text Available Abstract Background Combining multiple independent tests, when all test the same hypothesis and in the same direction, has been the subject of several approaches. Besides the inappropriate (in this case Bonferroni procedure, the Fisher's method has been widely used, in particular in population genetics. This last method has nevertheless been challenged by the SGM (symmetry around the geometric mean and Stouffer's Z-transformed methods that are less sensitive to asymmetry and deviations from uniformity of the distribution of the partial P-values. Performances of these different procedures were never compared on proportional data such as those currently used in population genetics. Results We present new software that implements a more recent method, the generalised binomial procedure, which tests for the deviation of the observed proportion of P-values lying under a chosen threshold from the expected proportion of such P-values under the null hypothesis. The respective performances of all available procedures were evaluated using simulated data under the null hypothesis with standard P-values distribution (differentiation tests. All procedures more or less behaved consistently with ~5% significant tests at α = 0.05. Then, linkage disequilibrium tests with increasing signal strength (rate of clonal reproduction, known to generate highly non-standard P-value distributions are undertaken and finally real population genetics data are analysed. In these cases, all procedures appear, more or less equally, very conservative, though SGM seems slightly more conservative. Conclusion Based on our results and those discussed in the literature we conclude that the generalised binomial and Stouffer's Z procedures should be preferred and Z when the number of tests is very small. The more conservative SGM might still be appropriate for meta-analyses when a strong publication bias in favour of significant results is expected to inflate type 2 error.

  3. Random protein association analyses of MALDI-TOF mass spectra of two- and three-component protein systems using binomial and multinomial distribution

    Science.gov (United States)

    Lee, Bao-Shiang; Krishnanchettiar, Sangeeth; Lateef, Syed Salman; Li, Chun-Ting; Gupta, Shalini

    2006-07-01

    The phenomenon of protein randomly associating among themselves during MALDI-TOF mass spectrometric measurements is manifest on all the proteins tested here. The magnitude of this random association seems to be protein-dependent. However, a detailed mathematical analysis of this process has not been reported so far. Here, binomial and multinomial equations are used to analyze the relative populations of multimer ions formed by random protein association during MALDI-TOF mass spectrometric measurements. Hemoglobin A (which consists of two [alpha]-globins and two [beta]-globins) and biotinylated insulin (which contains intact, singly biotinylated, and doubly biotinylated insulin) are used as the test cases for two- and three-component protein systems, respectively. MALDI-TOF spectra are acquired using standard MALDI-TOF techniques and equipment. The binomial distribution matches the relative populations of multimer ions of Hb A perfectly. For biotinylated insulin sample, taking lesser relative populations for doubly biotinylated insulin and intact insulin compared with singly biotinylated insulin into account, the relative populations of multimer ions of the biotinylated insulin confirms the prediction of multinomial equation. The pairs of unrelated proteins such as myoglobin, avidin, and lysozyme show lesser intensities for heteromultimers than for homomultimers, indicating weaker propensities to associate between different proteins during MALDI-TOF mass spectrometric measurements. Contrary to the suggestion that the multimer ions are formed in the solution phase prior to MALDI-TOF mass spectrometric measurement through multistage sequential reactions of the aggregation of protein molecules, we postulate that multimer ions of proteins are formed after the protein molecules have been vaporized into the gas phase through the assistance of the laser and matrix.

  4. The case for negative senescence

    DEFF Research Database (Denmark)

    Vaupel, James W; Baudisch, Annette; Dölling, Martin

    2004-01-01

    Negative senescence is characterized by a decline in mortality with age after reproductive maturity, generally accompanied by an increase in fecundity. Hamilton (1966) ruled out negative senescence: we adumbrate the deficiencies of his model. We review empirical studies of various plants and some...... kinds of animals that may experience negative senescence and conclude that negative senescence may be widespread, especially in indeterminate-growth species for which size and fertility increase with age. We develop optimization models of life-history strategies that demonstrate that negative senescence...

  5. Transmission dynamics of gram-negative bacterial pathogens in the anesthesia work area.

    Science.gov (United States)

    Loftus, Randy W; Brown, Jeremiah R; Patel, Hetal M; Koff, Matthew D; Jensen, Jens T; Reddy, Sundara; Ruoff, Kathryn L; Heard, Stephen O; Dodds, Thomas M; Beach, Michael L; Yeager, Mark P

    2015-04-01

    Gram-negative organisms are a major health care concern with increasing prevalence of infection and community spread. Our primary aim was to characterize the transmission dynamics of frequently encountered gram-negative bacteria in the anesthesia work area environment (AWE). Our secondary aim was to examine links between these transmission events and 30-day postoperative health care-associated infections (HCAIs). Gram-negative isolates obtained from the AWE (patient nasopharynx and axilla, anesthesia provider hands, and the adjustable pressure-limiting valve and agent dial of the anesthesia machine) at 3 major academic medical centers were identified as possible intraoperative bacterial transmission events by class of pathogen, temporal association, and phenotypic analysis (analytical profile indexing). The top 5 frequently encountered genera were subjected to antibiotic disk diffusion sensitivity to identify epidemiologically related transmission events. Complete multivariable logistic regression analysis and binomial tests of proportion were then used to examine the relative contributions of reservoirs of origin and within- and between-case modes of transmission, respectively, to epidemiologically related transmission events. Analyses were conducted with and without the inclusion of duplicate transmission events of the same genera occurring in a given study unit (first and second case of the day in each operating room observed) to examine the potential effect of statistical dependency. Transmitted isolates were compared by pulsed-field gel electrophoresis to disease-causing bacteria for 30-day postoperative HCAIs. The top 5 frequently encountered gram-negative genera included Acinetobacter, Pseudomonas, Brevundimonas, Enterobacter, and Moraxella that together accounted for 81% (767/945) of possible transmission events. For all isolates, 22% (167/767) of possible transmission events were identified by antibiotic susceptibility patterns as epidemiologically related

  6. Negative snakes in JET: evidence for negative shear

    International Nuclear Information System (INIS)

    Gill, R.D.; Alper, B.; Edwards, A.W.

    1994-01-01

    The signature of the negative snakes from the soft X-ray cameras is very similar to the more usual snakes except that the localised region of the snake has, compared with its surroundings, decreased rather than increased emission. Circumstances where negative snakes have been seen are reviewed. The negative snake appears as a region of increased resistance and of increased impurity density. The relationship between the shear and the current perturbation is shown, and it seem probable that the magnetic shear is reversed at the point of the negative snake, i.e. that q is decreasing with radius. 6 refs., 6 figs

  7. Macro-level pedestrian and bicycle crash analysis: Incorporating spatial spillover effects in dual state count models.

    Science.gov (United States)

    Cai, Qing; Lee, Jaeyoung; Eluru, Naveen; Abdel-Aty, Mohamed

    2016-08-01

    This study attempts to explore the viability of dual-state models (i.e., zero-inflated and hurdle models) for traffic analysis zones (TAZs) based pedestrian and bicycle crash frequency analysis. Additionally, spatial spillover effects are explored in the models by employing exogenous variables from neighboring zones. The dual-state models such as zero-inflated negative binomial and hurdle negative binomial models (with and without spatial effects) are compared with the conventional single-state model (i.e., negative binomial). The model comparison for pedestrian and bicycle crashes revealed that the models that considered observed spatial effects perform better than the models that did not consider the observed spatial effects. Across the models with spatial spillover effects, the dual-state models especially zero-inflated negative binomial model offered better performance compared to single-state models. Moreover, the model results clearly highlighted the importance of various traffic, roadway, and sociodemographic characteristics of the TAZ as well as neighboring TAZs on pedestrian and bicycle crash frequency. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Negative Attitudes, Network and Education

    DEFF Research Database (Denmark)

    Bennett, Patrick; la Cour, Lisbeth; Larsen, Birthe

    use Danish register data to find a signficant positive correlation between negative attitudes towards immigrants and high school attendance and find a positive impact of networking on high school attendance. In both the macro and the micro-econometric analysis we run the same regressions for natives......We consider the impact of negative attitudes against immigrants and immigration on educational choice in a search and wage bargaining model including networking. We consider two cases in terms of the importance of negative attitudes againts immigrants for high and low educated individuals and find...... that more negative attitudes against immigrants has a positive impact on education in one case and a negative impact in the other and has no impact on natives. Immigration improves employment perspectives for immigrants and thereby increases immigrant education whereas endogenous negative attitudes lead...

  9. Wages, Amenities and Negative Attitudes

    DEFF Research Database (Denmark)

    Waisman, Gisela; Larsen, Birthe

    We exploit the regional variation in negative attitudes towards immigrants to Sweden in order to analyse the consequences of the attitudes on immigrants welfare. We find that attitudes towards immigrants are of importance: they both affect their labour market outcomes and their quality of life. We...... interpret the negative effect on wages as evidence of labour market discrimination. We estimate the welfare effects of negative attitudes, through their wage and local amenities, for immigrants with different levels of skills, origin, gender and age....

  10. On Negation as Mitigation: The Case of Negative Irony

    Science.gov (United States)

    Giora, Rachel; Fein, Ofer; Ganzi, Jonathan; Levi, Natalie Alkeslassy; Sabah, Hadas

    2005-01-01

    Four experiments support the view of negation as mitigation (Giora, Balaban, Fein, & Alkabets, 2004). They show that when irony involves some sizable gap between what is said and what is criticized (He is exceptionally bright said of an idiot), it is rated as highly ironic (Giora, 1995). A negated version of that overstatement (He is not…

  11. Intense negative heavy ion sources

    Science.gov (United States)

    Mori, Yoshiharu; Takagi, Akira; Ikegami, Kiyoshi; Ueno, Akira; Fukumoto, Sadayoshi

    1990-08-01

    Negative ion sources based on plasma-surface interactions (BLAKE ion source) have been developed at KEK for producing negative heavy ions. The first negative heavy ion source (BLAKE-II) was developed by modifying the ordinary negative hydrogen ion source with converter (BLAKE-I) placed into the plasma. It generates various species of negative heavy ions with intense beam currents. For example, a more than 10 mA Au- ion beam was obtained from the ion source. Recently, the large scaled negative heavy ion source (BLAKE-III) has been developed and in the preliminary test experiment, more than 100 mA Cu- ion beam has been stably obtained with a 10% duty factor in pulsed operation. The BLAKE-II ion source was attached to the BNL 15 MV and Tsukuba University TANDEM accelerators and large current negative heavy ion beams were successfully accelerated in pulsed mode operation. Also, it was found that the space charge effect should be carefully considered for such a large current acceleration in a tandem accelerator, especially at the injection beam line and low energy end. In order to examine the negative ion formation process fundamentally, negative ion production probability related on sputtered particle velocity was measured and the results showed exponential dependence of the production probability on particle velocity as Norskov and Lindquist's theory predicted.

  12. Prestarlike functions with negative coefficients

    Directory of Open Access Journals (Sweden)

    H. Silverman

    1979-01-01

    Full Text Available The extreme points for prestarlike functions having negative coefficients are determined. Coefficient, distortion and radii of univalence, starlikeness, and convexity theorems are also obtained.

  13. Negative ions of polyatomic molecules

    International Nuclear Information System (INIS)

    Christophorou, LG.

    1980-01-01

    In this paper general concepts relating to, and recent advances in, the study of negative ions of polyatomic molecules are discussed with emphasis on halocarbons. The topics dealt with in the paper are as follows: basic electron attachment processes, modes of electron capture by molecules, short-lived transient negative ions, dissociative electron attachment to ground-state molecules and to hot molecules (effects of temperature on electron attachment), parent negative ions, effect of density, nature, and state of the medium on electron attachment, electron attachment to electronically excited molecules, the binding of attached electrons to molecules (electron affinity), and the basic and the applied significance of negative-ion studies

  14. Double-Negative Mechanical Metamaterials Displaying Simultaneous Negative Stiffness and Negative Poisson’s Ratio Properties

    OpenAIRE

    Hewage, Trishan A.M.; Alderson, Kim L; Alderson, Andrew; Scarpa, Fabrizio

    2016-01-01

    Intuitively, materials become both shorter and wider when compressed along their length. Here we show how a composite material or structure can display a simultaneous reversal in the direction of deformation for both the axial and transverse dimensions, corresponding to negative values of effective stiffness and effective Poisson’s ratio, respectively. A negative Poisson’s ratio[1] (NPR or auxetic[2]) host assembly stabilising (otherwise unstable) embedded negative stiffness[3] (NS) elements ...

  15. Negative supervisionsoplevelser og deres konsekvenser

    DEFF Research Database (Denmark)

    Nielsen, Jan

    2011-01-01

    in evaluation. First part of the paper explores negative experience in supervision in general. The second part, focusing on negative experience in supervision caused by evaluation, is explored and discussed in relation to the key concept of supervisory alliance (Bordin, 1983), perceiving evaluation...

  16. Research priorities for negative emissions

    NARCIS (Netherlands)

    Fuss, S.; Jones, C. D.; Kraxner, F.; Peters, G. P.; Smith, P.; Tavoni, M.; van Vuuren, Detlef; Canadell, J. G.; Jackson, R. B.; Milne, J.; Moreira, J. R.; Nakicenovic, N.; Sharifi, A.; Yamagata, Y.

    2016-01-01

    Carbon dioxide removal from the atmosphere (CDR) - also known as 'negative emissions' - features prominently in most 2 °C scenarios and has been under increased scrutiny by scientists, citizens, and policymakers. Critics argue that 'negative emission technologies' (NETs) are insufficiently mature to

  17. Income, Amenities and Negative Attitudes

    DEFF Research Database (Denmark)

    Waisman, Gisela; Larsen, Birthe

    2016-01-01

    We exploit the regional variation in negative attitudes towards immigrants to Sweden in order to analyse the consequences of negative attitudes on refugees’ utility from labour income and amenities. We find that attitudes towards immigrants are important: while they affect mainly the refugees...

  18. Question tags and sentential negativity

    NARCIS (Netherlands)

    Brasoveanu, A.; De Clercq, K.; Farkas, D.; Roelofsen, F.

    2014-01-01

    This paper presents an experiment that is designed to quantify the negativity of sentences with different types of negative operators (n-words like never and downward entailing operators like rarely) in different syntactic positions (adverb, subject, and direct object). In the experiment,

  19. Quasi-Poisson versus negative binomial regression models in identifying factors affecting initial CD4 cell count change due to antiretroviral therapy administered to HIV-positive adults in North-West Ethiopia (Amhara region).

    Science.gov (United States)

    Seyoum, Awoke; Ndlovu, Principal; Zewotir, Temesgen

    2016-01-01

    CD4 cells are a type of white blood cells that plays a significant role in protecting humans from infectious diseases. Lack of information on associated factors on CD4 cell count reduction is an obstacle for improvement of cells in HIV positive adults. Therefore, the main objective of this study was to investigate baseline factors that could affect initial CD4 cell count change after highly active antiretroviral therapy had been given to adult patients in North West Ethiopia. A retrospective cross-sectional study was conducted among 792 HIV positive adult patients who already started antiretroviral therapy for 1 month of therapy. A Chi square test of association was used to assess of predictor covariates on the variable of interest. Data was secondary source and modeled using generalized linear models, especially Quasi-Poisson regression. The patients' CD4 cell count changed within a month ranged from 0 to 109 cells/mm 3 with a mean of 15.9 cells/mm 3 and standard deviation 18.44 cells/mm 3 . The first month CD4 cell count change was significantly affected by poor adherence to highly active antiretroviral therapy (aRR = 0.506, P value = 2e -16 ), fair adherence (aRR = 0.592, P value = 0.0120), initial CD4 cell count (aRR = 1.0212, P value = 1.54e -15 ), low household income (aRR = 0.63, P value = 0.671e -14 ), middle income (aRR = 0.74, P value = 0.629e -12 ), patients without cell phone (aRR = 0.67, P value = 0.615e -16 ), WHO stage 2 (aRR = 0.91, P value = 0.0078), WHO stage 3 (aRR = 0.91, P value = 0.0058), WHO stage 4 (0876, P value = 0.0214), age (aRR = 0.987, P value = 0.000) and weight (aRR = 1.0216, P value = 3.98e -14 ). Adherence to antiretroviral therapy, initial CD4 cell count, household income, WHO stages, age, weight and owner of cell phone played a major role for the variation of CD4 cell count in our data. Hence, we recommend a close follow-up of patients to adhere the prescribed medication for achievements of CD4 cell count change progression.

  20. Isotropic Negative Thermal Expansion Metamaterials.

    Science.gov (United States)

    Wu, Lingling; Li, Bo; Zhou, Ji

    2016-07-13

    Negative thermal expansion materials are important and desirable in science and engineering applications. However, natural materials with isotropic negative thermal expansion are rare and usually unsatisfied in performance. Here, we propose a novel method to achieve two- and three-dimensional negative thermal expansion metamaterials via antichiral structures. The two-dimensional metamaterial is constructed with unit cells that combine bimaterial strips and antichiral structures, while the three-dimensional metamaterial is fabricated by a multimaterial 3D printing process. Both experimental and simulation results display isotropic negative thermal expansion property of the samples. The effective coefficient of negative thermal expansion of the proposed models is demonstrated to be dependent on the difference between the thermal expansion coefficient of the component materials, as well as on the circular node radius and the ligament length in the antichiral structures. The measured value of the linear negative thermal expansion coefficient of the three-dimensional sample is among the largest achieved in experiments to date. Our findings provide an easy and practical approach to obtaining materials with tunable negative thermal expansion on any scale.

  1. Negative Attitudes, Network and Education

    DEFF Research Database (Denmark)

    Bennett, Patrick; la Cour, Lisbeth; Larsen, Birthe

    This paper explores potential explanations behind the educational gap between young natives and immigrants using two measures, negative attitudes towards immigrants and networking, which may influence natives and immigrants differently. The paper considers, both theoretically and empirically......, the impact of negative attitudes and networking taking into account that these parameters may influence high and uneducated workers as well as immigrants and natives differently, creating different incentives to acquire education for the two ethnic groups. Using rich Danish administrative data, this paper...... finds evidence that greater negative attitudes increase incentives for males to acquire education and that networking also increases immigrant education....

  2. Mazindol treatment of negative symptoms.

    Science.gov (United States)

    Carpenter, W T; Breier, A; Buchanan, R W; Kirkpatrick, B; Shepard, P; Weiner, E

    2000-10-01

    Hypodopaminergic and hyponoradrenergic pathophysiology may be a basis for primary and/or secondary negative symptoms in schizophrenia. The hypothesis that enhanced neurotransmission in these systems would be therapeutic for negative symptoms was tested by comparing mazindol and placebo in a double-blind, cross-over design trial. Outcome following mazindol supplementation was comparable to placebo supplementation (F(1,30) = 0.9; p = .57). Results for deficit and non-deficit schizophrenia subjects were similar, and were not affected by whether concurrent the antipsychotic drug treatment was clozapine, fluphenazine, or haloperidol. The efficacy hypothesis was not supported for either primary or secondary negative symptoms.

  3. [APPLICATION OF NEGATIVE PRESSURE THERAPY].

    Science.gov (United States)

    Laginja, S; Marinović, M

    2016-01-01

    Negative pressure therapy is gradually taking an increasingly important role in the treatment of chronic wound healing because of its simple application in hospital or outpatient setting and good comfort with no pain for the patient. Chronic wound healing is accelerated in comparison with other conservative treatments. The level of negative pressure is between 40 and 125 mm Hg below ambient. Direct and indirect effect of the negative pressure therapy helps in wound healing and provides good preparation for definitive surgical management of wounds.

  4. Adjective metaphors evoke negative meanings.

    Directory of Open Access Journals (Sweden)

    Maki Sakamoto

    Full Text Available Previous metaphor studies have paid much attention to nominal metaphors and predicative metaphors, but little attention has been given to adjective metaphors. Although some studies have focused on adjective metaphors, they only examined differences in the acceptability of various types of adjective metaphors. This paper explores the cognitive effects evoked by adjective metaphors. Three psychological experiments revealed that (1 adjective metaphors, especially those modified by color adjectives, tend to evoke negative effect; (2 although the meanings of metaphors are basically affected by the meanings of their vehicles, when a vehicle has a neutral meaning, negative meanings are evoked most frequently for adjective metaphors compared to nominal and predicative metaphors; (3 negative meanings evoked by adjective metaphors are related to poeticness, and poetic metaphors evoke negative meanings more easily than less poetic metaphors. Our research sheds new light on studies of the use of metaphor, which is one of the most basic human cognitive abilities.

  5. Ferroelectric Negative Capacitance Domain Dynamics

    OpenAIRE

    Hoffmann, Michael; Khan, Asif Islam; Serrao, Claudy; Lu, Zhongyuan; Salahuddin, Sayeef; Pešić, Milan; Slesazeck, Stefan; Schroeder, Uwe; Mikolajick, Thomas

    2017-01-01

    Transient negative capacitance effects in epitaxial ferroelectric Pb(Zr$_{0.2}$Ti$_{0.8}$)O$_3$ capacitors are investigated with a focus on the dynamical switching behavior governed by domain nucleation and growth. Voltage pulses are applied to a series connection of the ferroelectric capacitor and a resistor to directly measure the ferroelectric negative capacitance during switching. A time-dependent Ginzburg-Landau approach is used to investigate the underlying domain dynamics. The transien...

  6. Negative magnetic relaxation in superconductors

    Directory of Open Access Journals (Sweden)

    Krasnoperov E.P.

    2013-01-01

    Full Text Available It was observed that the trapped magnetic moment of HTS tablets or annuli increases in time (negative relaxation if they are not completely magnetized by a pulsed magnetic field. It is shown, in the framework of the Bean critical-state model, that the radial temperature gradient appearing in tablets or annuli during a pulsed field magnetization can explain the negative magnetic relaxation in the superconductor.

  7. Use of Negation in Search

    Science.gov (United States)

    2010-06-01

    as of May 2010, produced a large number of images of Volkswagen Beetles as shown in Figure 8. After indicating they were ready to proceed... Volkswagen 1 beetle -VW -car 1 beetle –car - Volkswagen 1 beetle -VW - Volkswagen 1 beetle -VW -car - Volkswagen 1 black beetle Not within first 30...that had many Volkswagen Beetles in the results, why did you choose not to use negation?] 9. [Do you think that negation would have been useful in

  8. Engineered Endolysin-Based “Artilysins” To Combat Multidrug-Resistant Gram-Negative Pathogens

    Science.gov (United States)

    Briers, Yves; Walmagh, Maarten; Van Puyenbroeck, Victor; Cornelissen, Anneleen; Cenens, William; Aertsen, Abram; Oliveira, Hugo; Azeredo, Joana; Verween, Gunther; Pirnay, Jean-Paul; Miller, Stefan; Volckaert, Guido

    2014-01-01

    ABSTRACT The global threat to public health posed by emerging multidrug-resistant bacteria in the past few years necessitates the development of novel approaches to combat bacterial infections. Endolysins encoded by bacterial viruses (or phages) represent one promising avenue of investigation. These enzyme-based antibacterials efficiently kill Gram-positive bacteria upon contact by specific cell wall hydrolysis. However, a major hurdle in their exploitation as antibacterials against Gram-negative pathogens is the impermeable lipopolysaccharide layer surrounding their cell wall. Therefore, we developed and optimized an approach to engineer these enzymes as outer membrane-penetrating endolysins (Artilysins), rendering them highly bactericidal against Gram-negative pathogens, including Pseudomonas aeruginosa and Acinetobacter baumannii. Artilysins combining a polycationic nonapeptide and a modular endolysin are able to kill these (multidrug-resistant) strains in vitro with a 4 to 5 log reduction within 30 min. We show that the activity of Artilysins can be further enhanced by the presence of a linker of increasing length between the peptide and endolysin or by a combination of both polycationic and hydrophobic/amphipathic peptides. Time-lapse microscopy confirmed the mode of action of polycationic Artilysins, showing that they pass the outer membrane to degrade the peptidoglycan with subsequent cell lysis. Artilysins are effective in vitro (human keratinocytes) and in vivo (Caenorhabditis elegans). PMID:24987094

  9. [Negative symptoms and cerebral imaging].

    Science.gov (United States)

    Kaladjian, A; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    A number of neuroanatomical and neurofonctional abnormalities have been evidenced by cerebral imaging studies in patients suffering from schizophrenia. Nevertheless, those specifically associated with the negative symptoms of this disease are still insufficiently known. This work is a review of selected studies that have assessed the brain correlates of negative symptoms in schizophrenia. Approaches using structural imaging have highlighted reduction of gray matter density or cortical thickness associated with negative symptoms, which is rather sparsely distributed within the frontal and temporal regions, localized nevertheless more particularly in the frontal medial and orbitofrontal areas, as well as the amygdalo-hippocampic complex. These deficits are concurrent with a loss of integrity of the principal paths of white matter tracts between frontal and limbic regions. On the other hand, neurofonctional abnormalities associated with negative symptoms involve especially the frontal areas and limbic striatum. A disturbed functioning within the fronto-striatal loops, related to a striatal dopaminergic deficit, may represent a potential explanatory hypothesis of the negative symptoms of schizophrenia, as suggested by studies using Positron Emission Tomography on this topic or neuroimaging studies on the effects of antipsychotics. A better identification of the cerebral abnormalities associated with the negative dimension of schizophrenia, with regard to the lateralization of these abnormalities or to their changes during the course of the disease, could offer new therapeutic modalities for the treatment of this dimension which, until now, remains few responsive to conventional pharmacological treatments. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  10. SM-1 negative ion source

    International Nuclear Information System (INIS)

    Huang Zhenjun; Wang Jianzhen

    1987-01-01

    The working principle and characteristics of SM-1 Negative Ion Source is mainly introduced. In the instrument, there is a device to remove O 3 . This instrument can keep high density of negative ions which is generated by the electrical coronas setting out electricity at negative high voltage and can remove the O 3 component which is harmful to the human body. The density of negative ions is higher than 2.5 x 10 6 p./cm 3 while that of O 3 components is less than 1 ppb at the distance of 50 cm from the panel of the instrument. The instrument sprays negative ions automatically without the help of electric fan, so it works noiselessly. It is widely used in national defence, industry, agriculture, forestry, stock raising, sidelines and in the places with an equipment of low density of negative ion or high concentration of O 3 components. Besides, the instrument may also be used to treat diseases, to prevent against rot, to arrest bacteria, to purify air and so on

  11. Incisional Negative Pressure Wound Therapy

    DEFF Research Database (Denmark)

    Hyldig, Nana; Birke-Sorensen, Hanne; Kruse, Marie

    Aim: Postoperative wound complications make many surgical procedures unnecessarily complex, particularly in high-risk patients. Negative Pressure Wound Therapy is well recognized in the management of open wounds. In recent years, it has been introduced as well in the management of closed surgical...... incisions to reduce postoperative wound complications, though the evidence base to support this intervention is limited. The aim of this study was to assess if Negative Pressure Wound Therapy (NPWT) reduces postoperative complications when applied on closed surgical incisions. Method: A systematic review...

  12. Negative Attitudes, Networks and Education

    DEFF Research Database (Denmark)

    Bennett, Patrick; la Cour, Lisbeth; Larsen, Birthe

    This paper theoretically and empirically assesses the potential explanations behind the educational gap between young natives and immigrants using two measures, negative attitudes towards immigrants and networking. The paper considers that two these parameters may influence high and uneducated...... workers as well as immigrants and natives differently, creating different incentives to acquire education for the two groups. Using rich Danish administrative data, this paper finds suggestive evidence rejecting the theoretical case where negative attitudes decrease 1st generation immigrant education...... and indications that quality of networks seems to matter more for immigrants than the quantity of individuals in a potential network....

  13. Ecological effects of the invasive giant madagascar day gecko on endemic mauritian geckos: applications of binomial-mixture and species distribution models.

    Directory of Open Access Journals (Sweden)

    Steeves Buckland

    Full Text Available The invasion of the giant Madagascar day gecko Phelsuma grandis has increased the threats to the four endemic Mauritian day geckos (Phelsuma spp. that have survived on mainland Mauritius. We had two main aims: (i to predict the spatial distribution and overlap of P. grandis and the endemic geckos at a landscape level; and (ii to investigate the effects of P. grandis on the abundance and risks of extinction of the endemic geckos at a local scale. An ensemble forecasting approach was used to predict the spatial distribution and overlap of P. grandis and the endemic geckos. We used hierarchical binomial mixture models and repeated visual estimate surveys to calculate the abundance of the endemic geckos in sites with and without P. grandis. The predicted range of each species varied from 85 km2 to 376 km2. Sixty percent of the predicted range of P. grandis overlapped with the combined predicted ranges of the four endemic geckos; 15% of the combined predicted ranges of the four endemic geckos overlapped with P. grandis. Levin's niche breadth varied from 0.140 to 0.652 between P. grandis and the four endemic geckos. The abundance of endemic geckos was 89% lower in sites with P. grandis compared to sites without P. grandis, and the endemic geckos had been extirpated at four of ten sites we surveyed with P. grandis. Species Distribution Modelling, together with the breadth metrics, predicted that P. grandis can partly share the equivalent niche with endemic species and survive in a range of environmental conditions. We provide strong evidence that smaller endemic geckos are unlikely to survive in sympatry with P. grandis. This is a cause of concern in both Mauritius and other countries with endemic species of Phelsuma.

  14. Assessing outcomes of large-scale public health interventions in the absence of baseline data using a mixture of Cox and binomial regressions

    Science.gov (United States)

    2014-01-01

    Background Large-scale public health interventions with rapid scale-up are increasingly being implemented worldwide. Such implementation allows for a large target population to be reached in a short period of time. But when the time comes to investigate the effectiveness of these interventions, the rapid scale-up creates several methodological challenges, such as the lack of baseline data and the absence of control groups. One example of such an intervention is Avahan, the India HIV/AIDS initiative of the Bill & Melinda Gates Foundation. One question of interest is the effect of Avahan on condom use by female sex workers with their clients. By retrospectively reconstructing condom use and sex work history from survey data, it is possible to estimate how condom use rates evolve over time. However formal inference about how this rate changes at a given point in calendar time remains challenging. Methods We propose a new statistical procedure based on a mixture of binomial regression and Cox regression. We compare this new method to an existing approach based on generalized estimating equations through simulations and application to Indian data. Results Both methods are unbiased, but the proposed method is more powerful than the existing method, especially when initial condom use is high. When applied to the Indian data, the new method mostly agrees with the existing method, but seems to have corrected some implausible results of the latter in a few districts. We also show how the new method can be used to analyze the data of all districts combined. Conclusions The use of both methods can be recommended for exploratory data analysis. However for formal statistical inference, the new method has better power. PMID:24397563

  15. Ecological effects of the invasive giant madagascar day gecko on endemic mauritian geckos: applications of binomial-mixture and species distribution models.

    Science.gov (United States)

    Buckland, Steeves; Cole, Nik C; Aguirre-Gutiérrez, Jesús; Gallagher, Laura E; Henshaw, Sion M; Besnard, Aurélien; Tucker, Rachel M; Bachraz, Vishnu; Ruhomaun, Kevin; Harris, Stephen

    2014-01-01

    The invasion of the giant Madagascar day gecko Phelsuma grandis has increased the threats to the four endemic Mauritian day geckos (Phelsuma spp.) that have survived on mainland Mauritius. We had two main aims: (i) to predict the spatial distribution and overlap of P. grandis and the endemic geckos at a landscape level; and (ii) to investigate the effects of P. grandis on the abundance and risks of extinction of the endemic geckos at a local scale. An ensemble forecasting approach was used to predict the spatial distribution and overlap of P. grandis and the endemic geckos. We used hierarchical binomial mixture models and repeated visual estimate surveys to calculate the abundance of the endemic geckos in sites with and without P. grandis. The predicted range of each species varied from 85 km2 to 376 km2. Sixty percent of the predicted range of P. grandis overlapped with the combined predicted ranges of the four endemic geckos; 15% of the combined predicted ranges of the four endemic geckos overlapped with P. grandis. Levin's niche breadth varied from 0.140 to 0.652 between P. grandis and the four endemic geckos. The abundance of endemic geckos was 89% lower in sites with P. grandis compared to sites without P. grandis, and the endemic geckos had been extirpated at four of ten sites we surveyed with P. grandis. Species Distribution Modelling, together with the breadth metrics, predicted that P. grandis can partly share the equivalent niche with endemic species and survive in a range of environmental conditions. We provide strong evidence that smaller endemic geckos are unlikely to survive in sympatry with P. grandis. This is a cause of concern in both Mauritius and other countries with endemic species of Phelsuma.

  16. Production of negative helium ions

    International Nuclear Information System (INIS)

    Toledo, A.S. de; Sala, O.

    1977-01-01

    A negative helium ion source using potassium charge exchange vapor has been developed to be used as an injector for the Pelletron accelerator. 3 He and α beam currents of up to 2μA have been extracted with 75% particle transmission through the machine [pt

  17. Unimode metamaterials exhibiting negative linear compressibility and negative thermal expansion

    International Nuclear Information System (INIS)

    Dudek, Krzysztof K; Attard, Daphne; Caruana-Gauci, Roberto; Grima, Joseph N; Wojciechowski, Krzysztof W

    2016-01-01

    Unimode metamaterials made from rotating rigid triangles are analysed mathematically for their mechanical and thermal expansion properties. It is shown that these unimode systems exhibit positive Poisson’s ratios irrespective of size, shape and angle of aperture, with the Poisson’s ratio exhibiting giant values for certain conformations. When the Poisson’s ratio in one loading direction is larger than +1, the systems were found to exhibit the anomalous property of negative linear compressibility along this direction, that is, the systems expand in this direction when hydrostatically compressed. Also discussed are the thermal expansion properties of these systems under the assumption that the units exhibit increased rotational agitation once subjected to an increase in temperature. The effect of the geometric parameters on the aforementioned thermo-mechanical properties of the system, are discussed, with the aim of identifying negative behaviour. (paper)

  18. Proclus’ View about Negative Theology

    Directory of Open Access Journals (Sweden)

    S Rahimiyan

    2012-09-01

    Full Text Available Negative theology is a modern theological approach that idiomatically implies those theological doctrines which are based on the negative premises and concepts for describing God. Among Greeks, this approach was on its climax in Neo-Platonism. Proclus is one of the Neo-Platonists who lived in fifth century (A.D and was in charge of Athena academy for years. He was the most important Neo-Platonist after Plotinus. In his philosophical system, on the one hand, it is impossible to recognize the first source and, on the other hand, the existence of some principles like the relationship between the creator and the universe, reversion and the way of emanation receiving, requires the knowledge of the first source. It seems that such paradox can be resolved by separating the stages of existence order.

  19. Negation switching invariant signed graphs

    Directory of Open Access Journals (Sweden)

    Deepa Sinha

    2014-04-01

    Full Text Available A signed graph (or, $sigraph$ in short is a graph G in which each edge x carries a value $\\sigma(x \\in \\{-, +\\}$ called its sign. Given a sigraph S, the negation $\\eta(S$ of the sigraph S is a sigraph obtained from S by reversing the sign of every edge of S. Two sigraphs $S_{1}$ and $S_{2}$ on the same underlying graph are switching equivalent if it is possible to assign signs `+' (`plus' or `-' (`minus' to vertices of $S_{1}$ such that by reversing the sign of each of its edges that has received opposite signs at its ends, one obtains $S_{2}$. In this paper, we characterize sigraphs which are negation switching invariant and also see for what sigraphs, S and $\\eta (S$ are signed isomorphic.

  20. Negative ion detachment cross sections

    International Nuclear Information System (INIS)

    Champion, R.L.; Doverspike, L.D.

    1992-10-01

    The authors have measured absolute cross sections for electron detachment and charge exchange for collision of O and S with atomic hydrogen, have investigated the sputtering and photodesorption of negative ions from gas covered surfaces, and have begun an investigation of photon-induced field emission of electrons from exotic structures. Brief descriptions of these activities as well as future plans for these projects are given below

  1. Weak negation in inquisitive semantics

    Czech Academy of Sciences Publication Activity Database

    Punčochář, Vít

    2015-01-01

    Roč. 24, č. 3 (2015), s. 323-355 ISSN 0925-8531 R&D Projects: GA ČR(CZ) GA13-21076S Institutional support: RVO:67985955 Keywords : inquisitive semantics * negation * possible worlds * Fitch-style natural deduction * denial Subject RIV: AA - Philosophy ; Religion Impact factor: 0.450, year: 2015 http://link.springer.com/article/10.1007%2Fs10849-015-9219-2

  2. A Semantic Analysis of Negative Concord

    NARCIS (Netherlands)

    Wouden van der, Ton; Zwarts, Frans

    1993-01-01

    It is not uncommon in natural languages that negation seems to behave in an illogical manner. The general term for the many cases where multiple occurrences of morphologically negative constituents express a single semantic negation is negative concord (Labov 1979). Negative concord may take either

  3. Research priorities for negative emissions

    Science.gov (United States)

    Fuss, S.; Jones, C. D.; Kraxner, F.; Peters, G. P.; Smith, P.; Tavoni, M.; van Vuuren, D. P.; Canadell, J. G.; Jackson, R. B.; Milne, J.; Moreira, J. R.; Nakicenovic, N.; Sharifi, A.; Yamagata, Y.

    2016-11-01

    Carbon dioxide removal from the atmosphere (CDR)—also known as ‘negative emissions’—features prominently in most 2 °C scenarios and has been under increased scrutiny by scientists, citizens, and policymakers. Critics argue that ‘negative emission technologies’ (NETs) are insufficiently mature to rely on them for climate stabilization. Some even argue that 2 °C is no longer feasible or might have unacceptable social and environmental costs. Nonetheless, the Paris Agreement endorsed an aspirational goal of limiting global warming to even lower levels, arguing that climate impacts—especially for vulnerable nations such as small island states—will be unacceptably severe in a 2 °C world. While there are few pathways to 2 °C that do not rely on negative emissions, 1.5 °C scenarios are barely conceivable without them. Building on previous assessments of NETs, we identify some urgent research needs to provide a more complete picture for reaching ambitious climate targets, and the role that NETs can play in reaching them.

  4. Negative Reflecting Meta-Mirrors.

    Science.gov (United States)

    Yang, Rui; Li, Dong; Gao, Dongxing; Zhang, Aofang; Hu, Bowei; Yang, Pei; Lei, Zhenya; Li, Jiacheng

    2017-07-18

    Using the gradient phase discontinuities that meta-mirrors provide, we show that the incident wave can be reflected anomalously with a broad angle range of negative reflections. Such reversed behaviors promote the immediate applications for the planar meta-mirrors to steer the signals more arbitrarily and the convex meta-mirrors to focus and collimate electromagnetic fields. We practically implement these negative reflecting meta-mirrors through an arrangement of subwavelength ring patches and generate the desired phase distribution by also considering the incident angle. Finally, the experiments are carried out to verify the functionality of the convex meta-mirror firstly, and the performances of the planar meta-mirror are also tested by further building up a dual reflector system with the demonstration of obtaining the plane wave from the convex meta-mirror and then having the well collimated beam negative reflected by the planar meta-mirror. The proposed design should be readily applicable to a wide range of electromagnetic problems, especially for devising smart planar illusion devices, and highly directive antennas mounting on convex surfaces of various platforms.

  5. Negative-Pressure Pulmonary Edema.

    Science.gov (United States)

    Bhattacharya, Mallar; Kallet, Richard H; Ware, Lorraine B; Matthay, Michael A

    2016-10-01

    Negative-pressure pulmonary edema (NPPE) or postobstructive pulmonary edema is a well-described cause of acute respiratory failure that occurs after intense inspiratory effort against an obstructed airway, usually from upper airway infection, tumor, or laryngospasm. Patients with NPPE generate very negative airway pressures, which augment transvascular fluid filtration and precipitate interstitial and alveolar edema. Pulmonary edema fluid collected from most patients with NPPE has a low protein concentration, suggesting hydrostatic forces as the primary mechanism for the pathogenesis of NPPE. Supportive care should be directed at relieving the upper airway obstruction by endotracheal intubation or cricothyroidotomy, institution of lung-protective positive-pressure ventilation, and diuresis unless the patient is in shock. Resolution of the pulmonary edema is usually rapid, in part because alveolar fluid clearance mechanisms are intact. In this review, we discuss the clinical presentation, pathophysiology, and management of negative-pressure or postobstructive pulmonary edema. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  6. Two negations for the price of one

    Directory of Open Access Journals (Sweden)

    Rosalind Thornton

    2016-11-01

    Full Text Available Standard English is typically described as a double negation language. In double negation ­languages, each negative marker contributes independent semantic force. Two negations in the same clause usually cancel each other out, resulting in an affirmative sentence. Other dialects of English permit negative concord. In negative concord sentences, the two negative markers yield a single semantic negation. This paper explores how English-speaking children interpret sentences with more than one negative element, in order to assess whether their early grammar allows negative concord. According to Zeijlstra’s (2004 typological generalization, if a language has a negative syntactic head, it will be a negative concord language. Since Standard English is often analysed as having a negative head, it represents an apparent exception to Zeijlstra’s ­generalization. This raises the intriguing possibility that initially, children recognize that English has a negative head (i.e., 'n’t' and, therefore, assign negative concord interpretations to sentences with two negations, despite the absence of evidence for this interpretation in the adult input. The present study investigated this possibility in a comprehension study with 20 3- to 5-year-old ­children and a control group of 15 adults. The test sentences were presented in contexts that made them amenable to either a double negation or a negative concord interpretation. As expected, the adult participants assigned the double negation interpretation of the test sentences the majority of the time. In contrast, the child participants assigned the alternative, negative concord interpretation the majority of the time. Children must jettison the negative concord interpretation of sentences with two negative markers, and acquire a double negation interpretation. We propose that the requisite positive evidence is the appearance of negative expressions like 'nothing 'in object position. Because such

  7. [Alexithymia in negative symptom and non-negative symptom schizophrenia].

    Science.gov (United States)

    Nkam, I; Langlois-Thery, S; Dollfus, S; Petit, M

    1997-01-01

    Coined by Sifneos in 1972, alexithymia refers to a relative narrowing in emotional functioning, an inability to find appropriate words to describe their emotions and, a poverty of fantasy life. Although initially described in the context of psychosomatic illness, alexithymic characteristics may be observed in patients with a wide range of medical and psychiatric disorders: Parkinson disease, depression, anxiety, substance abuse and eating disorders. Flattening of affect and poverty of speech, major negative symptoms, referred to chronic schizophrenia: there is a lack of outward display of emotion. Accordingly, some disturbances of alexithymia's scores would be expected in schizophrenic patients. The purpose of this study was to estimate and compare the prevalence of alexithymia in deficit and non-deficit schizophrenia. The term "deficit symptoms" may be used as Carpenter, to refer specifically to those negative symptoms that are not considered secondary. The influence of patients' symptoms has also been studied on alexithymia scores: negative and positive symptoms of schizophrenia, depression, anxiety, anhedonia and effects of neuroleptics. Twenty-five patients, meeting DSM III-R criteria for schizophrenia have been studied. All of them treated by neuroleptics, were in a stable clinical status for at least one month. The patients have been categorized into deficit (n = 12) and non-deficit (n = 13) subgroups by one trained psychiatrist (SD), using the Schedule for the Deficit Syndrome. The subjects have been assessed by the same rater (IN), blind to deficit status, using six rating scales: Beth Israel Questionnaire (BIQ) and Toronto Alexithymia Scale (TAS) for alexithymia, Positive and Negative Syndrome Scale (PANSS), Montgomery and Asberg Depression Rating Scale (MADRS), revised Physical Anhedonia Scale (PAS), and finally, Extrapyramidal Symptom Rating Scale (ESRS). Using TAS, alexithymic characteristics were more prevalent in the deficit subgroup as compared to

  8. Humans in space the psychological hurdles

    CERN Document Server

    Kanas, Nick

    2015-01-01

    Using anecdotal reports from astronauts and cosmonauts, and the results from studies conducted in space analog environments on Earth and in the actual space environment, this book broadly reviews the various psychosocial issues that affect space travelers.  Unlike other books that are more technical in format, this text is targeted for the general public.  With the advent of space tourism and the increasing involvement of private enterprise in space, there is now a need to explore the impact of space missions on the human psyche and on the interpersonal relationships of the crewmembers. Separate chapters of the book deal with psychosocial stressors in space and in space analog environments; psychological, psychiatric, interpersonal, and cultural issues pertaining to space missions; positive growth-enhancing aspects of space travel; the crew-ground interaction; space tourism; countermeasures for dealing with space; and unique aspects of a trip to Mars, the outer solar system, and interstellar travel. .

  9. Defining the Critical Hurdles in Cancer Immunotherapy

    NARCIS (Netherlands)

    Fox, BA; Schendel, D.J.; Butterfield, L.H.; Aamdal, S.; Allison, J.P.; Ascierto, P.A.; Atkins, M.B.; Bartunkova, J.; Bergmann, L.; Berinstein, N.; Bonorino, C.C.; Borden, E.; Bramson, J.L.; Britten, C.M.; Cao, X.; Carson, W.E.; Chang, A.E.; Characiejus, D.; Choudhury, A.R.; Coukos, G.; de Gruijl, T.D.; Dillman, R.O.; Dolstra, H.; Dranoff, G.; Durrant, L.G.; Finke, J.H.; Galon, J.; Gollob, J.A.; Gouttefangeas, C.; Grizzi, F.; Guida, M.; Hakansson, L.; Hege, K.; Herberman, R.B.; Hodi, F.S.; Hoos, A.; Huber, C.; Hwu, P.; Imai, K.; Jaffee, E.M.; Janetzki, S.; June, C.H.; Kalinski, P.; Kaufmann, H.L.; Kawakami, K.; Kawakami, Y.; Keilholtz, U.; Khleif, S.N.; Kiessling, R.; Kotlan, B.; Kroemer, G.; Lapointe, R.; Levitsky, H.I.; Lotze, M.T.; Di Maio, M.; Marschner, J.P.; Mastrangelo, M.J.; Masucci, G.; Melero, I.; Nelief, C.; Murphy, W.J.; Nelson, B.; Nicolini, A.; Nishimura, M.I.; Odunsi, K.; Ohashi, P.S.; O'Donnell-Tormey, J.; Old, L.J.; Ottensmeier, C.; Papamichail, M.; Parmiani, G.; Pawelec, G.; Proietti, E.; Qin, S.; Rees, R.; Ribas, A.; Ridolfi, R.; Ritter, G.; Rivoltini, L.; Romero, P.J.; Salem, M.L.; Scheper, R.J.; Seliger, B.; Sharma, P.; Shiku, H.; Singh-Jasuja, H.; Song, W.; Straten, P.T.; Tahara, H.; Tian, Z.; van der Burg, S.H.; von Hoegen, P.; Wang, E.; Welters, M.J.; Winter, H.; Withington, T.; Wolchok, J.D.; Xiao, W.; Zitvogel, L.; Zwierzina, H.; Marincola, F.M.; Gajewski, T.F.; Wigginton, J.M.; Disis, M.L.A.

    2011-01-01

    Scientific discoveries that provide strong evidence of antitumor effects in preclinical models often encounter significant delays before being tested in patients with cancer. While some of these delays have a scientific basis, others do not. We need to do better. Innovative strategies need to move

  10. Artificial insemination history: hurdles and milestones

    OpenAIRE

    Ombelet, W.; Van Robays, J.

    2015-01-01

    Artificial insemination with homologous (AIH) or donor semen (AID) is nowadays a very popular treatment procedure used for many subfertile women worldwide. The rationale behind artificial insemination is to increase gamete density at the site of fertilisation. The sequence of events leading to today's common use of artificial insemination traces back to scientific studies and experimentation many centuries ago. Modern techniques used in human artificial insemination programmes are mostly adap...

  11. Oil and gas supply : hurdles and opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Giusti, L. [Centre for Strategic and International Studies, Washington, DC (United States)

    2006-07-01

    The socioeconomic development in Latin America was discussed with reference to its abundant and diverse resources. Despite its large population, Latin America represents only 6 per cent of the world gross domestic product (GDP) and a less than 6 per cent of the total world trading. This presentation described the problems of large deficits, poor economic policies, large debt and corruption that provoked inflation, economic slowdown, and foreign debt in Latin America. Policy makers agreed that reforms were needed if Latin American economies were to grow more than 6 per cent a year, and to lower the number of people living in poverty in the region. The second-generation reform for Latin America was meant to promote economic development without inflation. It is based on quality public sector governance; fiscal strengthening; an enhanced legal and regulatory framework; efficient financial markets; and, labour and market reform. This presentation also discussed the oil and gas industry's contention with the perceptions that the economic crisis in Latin America was caused by globalization, international trade and acquisitive industrialized countries. An initiative was launched in 1994 to build an integrated energy data bank, evaluate existing interconnections among Latin American countries, and identify barriers for a larger integration to facilitate and improve commercial activities. It was emphasized that while the United States has a large deficit of oil, Canada and Latin America have large surpluses of energy resources, which if developed efficiently and effectively, can be a leading engine of regional development and an important contributor to global competitiveness. Canada is the largest supplier of energy, including oil, natural gas and electricity to the United States, the world's largest energy consumer and largest oil and gas market. Mexico and Brazil were identified as the other 2 large economies in the region's energy chain, but Mexico is self sufficient and Brazil has a modest dependency. The important players on the supply side include Mexico, Brazil, Venezuela and Trinidad/Tobago. Also, Colombia is a player with its excellent exploration and production model, its stability and institutional strength. It was suggested that Bolivia could become an important player if changes take place to promote the development of its huge natural gas resources.

  12. Hovercraft transportation in Alaska : CZM & NEPA hurdles.

    Science.gov (United States)

    2001-05-31

    The United States Postal Service (USPS) received an unsolicited proposal from Alaska Hovercraft Joint Venture for a two-year demonstration program for the transport of : bypass and non-priority mail by Hovercraft on a year-round basis from the city o...

  13. Gender is another hurdle for S. Africa.

    Science.gov (United States)

    Hill, M

    1993-11-05

    Gender equality remains an unacceptable concept to traditional tribal leaders in the new South Africa. Representative of this opposition to an equality for women provision in the new Constitution is Mwelo Nonkonyana, chief of the Amabhala clan of the Xhosa tribe in South Africa's Transkei region. Chief Nonkonyana has insisted, "Women are not inferior. It's just that they perform a special function." A ban on sex discrimination in South Africa would enable daughters to sue the eldest son for the right to assume power and pose many challenges to the institution of polygamy. Traditional leaders have proposed a separate parliamentary body composed of kings and chiefs to examine instances where proposed laws conflict with tribal practices, a step that could delay action on the gender equality plank for 5 years. They are being opposed by the African National Congress, which insists on the inclusion of human rights for all in the new Constitution. The Congress is committed to accommodating the tribal rulers, many of whom received financial support from the apartheid government, but is determined to avoid the existence of two parallel ruling structures in the new South Africa.

  14. Hurdles in Acquiring the Number Word Sequence

    Science.gov (United States)

    Gould, Peter

    2016-01-01

    Learning the sequence of number words in English up to 30 is not a simple process. In NSW government schools taking part in "Early Action for Success," over 800 students in each of the first 3 years of school were assessed every 5 weeks over the school year to determine the highest correct oral count they could produce. Rather than…

  15. Oil and gas supply : hurdles and opportunities

    International Nuclear Information System (INIS)

    Giusti, L.

    2006-01-01

    The socioeconomic development in Latin America was discussed with reference to its abundant and diverse resources. Despite its large population, Latin America represents only 6 per cent of the world gross domestic product (GDP) and a less than 6 per cent of the total world trading. This presentation described the problems of large deficits, poor economic policies, large debt and corruption that provoked inflation, economic slowdown, and foreign debt in Latin America. Policy makers agreed that reforms were needed if Latin American economies were to grow more than 6 per cent a year, and to lower the number of people living in poverty in the region. The second-generation reform for Latin America was meant to promote economic development without inflation. It is based on quality public sector governance; fiscal strengthening; an enhanced legal and regulatory framework; efficient financial markets; and, labour and market reform. This presentation also discussed the oil and gas industry's contention with the perceptions that the economic crisis in Latin America was caused by globalization, international trade and acquisitive industrialized countries. An initiative was launched in 1994 to build an integrated energy data bank, evaluate existing interconnections among Latin American countries, and identify barriers for a larger integration to facilitate and improve commercial activities. It was emphasized that while the United States has a large deficit of oil, Canada and Latin America have large surpluses of energy resources, which if developed efficiently and effectively, can be a leading engine of regional development and an important contributor to global competitiveness. Canada is the largest supplier of energy, including oil, natural gas and electricity to the United States, the world's largest energy consumer and largest oil and gas market. Mexico and Brazil were identified as the other 2 large economies in the region's energy chain, but Mexico is self sufficient and Brazil has a modest dependency. The important players on the supply side include Mexico, Brazil, Venezuela and Trinidad/Tobago. Also, Colombia is a player with its excellent exploration and production model, its stability and institutional strength. It was suggested that Bolivia could become an important player if changes take place to promote the development of its huge natural gas resources

  16. Modelling marine protected areas: insights and hurdles

    Science.gov (United States)

    Fulton, Elizabeth A.; Bax, Nicholas J.; Bustamante, Rodrigo H.; Dambacher, Jeffrey M.; Dichmont, Catherine; Dunstan, Piers K.; Hayes, Keith R.; Hobday, Alistair J.; Pitcher, Roland; Plagányi, Éva E.; Punt, André E.; Savina-Rolland, Marie; Smith, Anthony D. M.; Smith, David C.

    2015-01-01

    Models provide useful insights into conservation and resource management issues and solutions. Their use to date has highlighted conditions under which no-take marine protected areas (MPAs) may help us to achieve the goals of ecosystem-based management by reducing pressures, and where they might fail to achieve desired goals. For example, static reserve designs are unlikely to achieve desired objectives when applied to mobile species or when compromised by climate-related ecosystem restructuring and range shifts. Modelling tools allow planners to explore a range of options, such as basing MPAs on the presence of dynamic oceanic features, and to evaluate the potential future impacts of alternative interventions compared with ‘no-action’ counterfactuals, under a range of environmental and development scenarios. The modelling environment allows the analyst to test if indicators and management strategies are robust to uncertainties in how the ecosystem (and the broader human–ecosystem combination) operates, including the direct and indirect ecological effects of protection. Moreover, modelling results can be presented at multiple spatial and temporal scales, and relative to ecological, economic and social objectives. This helps to reveal potential ‘surprises', such as regime shifts, trophic cascades and bottlenecks in human responses. Using illustrative examples, this paper briefly covers the history of the use of simulation models for evaluating MPA options, and discusses their utility and limitations for informing protected area management in the marine realm. PMID:26460131

  17. GIS in oceanography: Status, hurdles and prospects

    Digital Repository Service at National Institute of Oceanography (India)

    Kunte, P.D.

    stream_size 5 stream_content_type text/plain stream_name Remote_Sens_GIS_Environ_Plan_1995_575.pdf.txt stream_source_info Remote_Sens_GIS_Environ_Plan_1995_575.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  18. Hurdles on the road to personalized medicine

    NARCIS (Netherlands)

    Tursz, Thomas; Bernards, Rene

    2015-01-01

    Cancer treatment is slowly shifting from an approach in which the tissue of origin and the histology were the guiding principles for the choice of chemotherapy towards a genotype-centric approach in which the changes in the cancer genome are used to select patients for treatment with highly

  19. Estudo por simulação Monte Carlo de um estimador robusto utilizado na inferência de um modelo binomial contaminado = A Monte Carlo simulation study of a robust estimator used in the inference of a contaminated binomial model

    Directory of Open Access Journals (Sweden)

    Marcelo Angelo Cirillo

    2010-07-01

    Full Text Available A inferencia estatistica em populacoes binomiais contaminadas esta sujeita a erros grosseiros de estimacao, uma vez que as amostras nao sao identicamente distribuidas. Por esse problema, este trabalho tem por objetivo determinar qual a melhor constante de afinidade (c1 que proporcione melhor desempenho em um estimador pertencente a classedos estimadores-E. Com esse proposito, neste trabalho, foi utilizada a metodologia, considerando-se o metodo de simulacao Monte Carlo, no qual diferentes configuracoes descritas pela combinacao de valores parametricos, niveis de contaminacao e tamanhos de amostra foram avaliados. Concluiu-se que, para alta probabilidade de mistura (ƒÁ = 0,40, recomenda-se assumir c1 = 0,1 nas situacoes de grandes amostras (n = 50 e n = 80. The statistical inference in binomial population is subject to gross errors of estimate, as the samples are not identically distributed. Due to this problem, this work aims to determine which is the best affinity constant (c1 that provides the best performance in the estimator, belonging to the class of E-estimators. With that purpose, the methodology used in this work was applied considering the Monte Carlo simulation method, in which different configurations described by combination of parametric values, levels of contamination and sample sizes were appraised. It was concluded that for the high probability of contamination (ƒÁ = 0.40, c1 = 0.1 is recommended in cases with large samples (n = 50 and n = 80.

  20. Superluminal travel requires negative energies

    OpenAIRE

    Olum, Ken D.

    1998-01-01

    I investigate the relationship between faster-than-light travel and weak-energy-condition violation, i.e., negative energy densities. In a general spacetime it is difficult to define faster-than-light travel, and I give an example of a metric which appears to allow superluminal travel, but in fact is just flat space. To avoid such difficulties, I propose a definition of superluminal travel which requires that the path to be traveled reach a destination surface at an earlier time than any neig...

  1. Imagery mismatch negativity in musicians.

    Science.gov (United States)

    Herholz, Sibylle C; Lappe, Claudia; Knief, Arne; Pantev, Christo

    2009-07-01

    The present study investigated musical imagery in musicians and nonmusicians by means of magnetoencephalography (MEG). We used a new paradigm in which subjects had to continue familiar melodies in their mind and then judged if a further presented tone was a correct continuation of the melody. Incorrect tones elicited an imagery mismatch negativity (iMMN) in musicians but not in nonmusicians. This finding suggests that the MMN component can be based on an imagined instead of a sensory memory trace and that imagery of music is modulated by musical expertise.

  2. The negation phenomenon. Aquiring French negation by Romanian native speakers

    Directory of Open Access Journals (Sweden)

    Liliana-Sonia IONESCU

    2011-01-01

    Full Text Available The present paper sets out some guidelines for a strategy based on the comparison ofRomanian and French and outlines some ways of learning the French negation by the nativespeakers of Romanian; the paper also points out a number of difficulties they face in assimilatingnegation in French. By highlighting some difficulties in assimilating the new language, based on thecontrastive analysis, these must be taken into consideration and ameliorated, to prevent theoccurrence of the default errors.The process of mastering a language is highly conditioned by the practicing of the studiedlanguage, i.e. a system of applications / structural exercises based on similarity and oppositionwithin a language, to allow the formation of spontaneous speech and understanding skills.

  3. Optimization of negative ion accelerators

    International Nuclear Information System (INIS)

    Pamela, J.

    1991-01-01

    We have started to study negative ion extraction and acceleration systems in view of designing a 1 MeV D - accelerator. This study is being made with a two-Dimensional code that has been specifically developed in our laboratory and validated by comparison to three sets of experimental data. We believe that the criteria for negative ion accelerator design optimization should be: (i) to provide the best optics; (ii) to reduce the power load on the extraction grid; (iii) to allow operation with low electric fields in order to reduce the problem of breakdowns. We show some results of optics calculations performed for two systems that will be operational in the next months: the CEA-JAERI collaboration at Cadarache and the european DRAGON experiment at Culham. Extrapolations to higher energies of 500 to 1100 keV have also been conducted. All results indicate that the overall accelerator length, whatever be the number of gaps, is constrained by space charge effects (Child-Langmuir). We have combined this constraint with high-voltage hold-off empirical laws. As a result, it appears that accelerating 10 mA/cm 2 of D - at 1 MeV with good optics, as required for NET or ITER, is close to the expected limit of high-voltage hold-off

  4. Negative regulators of cell proliferation

    Science.gov (United States)

    Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    Cell proliferation is governed by the influence of both mitogens and inhibitors. Although cell contact has long been thought to play a fundamental role in cell cycling regulation, and negative regulators have long been suspected to exist, their isolation and purification has been complicated by a variety of technical difficulties. Nevertheless, over recent years an ever-expanding list of putative negative regulators have emerged. In many cases, their biological inhibitory activities are consistent with density-dependent growth inhibition. Most likely their interactions with mitogenic agents, at an intracellular level, are responsible for either mitotic arrest or continued cell cycling. A review of naturally occurring cell growth inhibitors is presented with an emphasis on those factors shown to be residents of the cell surface membrane. Particular attention is focused on a cell surface sialoglycopeptide, isolated from intact bovine cerebral cortex cells, which has been shown to inhibit the proliferation of an unusually wide range of target cells. The glycopeptide arrest cells obtained from diverse species, both fibroblasts and epithelial cells, and a broad variety of transformed cells. Signal transduction events and a limited spectrum of cells that are refractory to the sialoglycopeptide have provided insight into the molecular events mediated by this cell surface inhibitor.

  5. Serotonin, inhibition, and negative mood.

    Directory of Open Access Journals (Sweden)

    Peter Dayan

    2008-02-01

    Full Text Available Pavlovian predictions of future aversive outcomes lead to behavioral inhibition, suppression, and withdrawal. There is considerable evidence for the involvement of serotonin in both the learning of these predictions and the inhibitory consequences that ensue, although less for a causal relationship between the two. In the context of a highly simplified model of chains of affectively charged thoughts, we interpret the combined effects of serotonin in terms of pruning a tree of possible decisions, (i.e., eliminating those choices that have low or negative expected outcomes. We show how a drop in behavioral inhibition, putatively resulting from an experimentally or psychiatrically influenced drop in serotonin, could result in unexpectedly large negative prediction errors and a significant aversive shift in reinforcement statistics. We suggest an interpretation of this finding that helps dissolve the apparent contradiction between the fact that inhibition of serotonin reuptake is the first-line treatment of depression, although serotonin itself is most strongly linked with aversive rather than appetitive outcomes and predictions.

  6. Entanglement negativity in the multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, Sugumi [Department of Theoretical Physics and History of Science, University of the Basque Country UPV/EHU, 48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013, Bilbao (Spain); Laboratory for Quantum Gravity & Strings and Astrophysics, Cosmology & Gravity Center, Department of Mathematics & Applied Mathematics, University of Cape Town, Private Bag, Rondebosch 7701 (South Africa); Shock, Jonathan P. [Laboratory for Quantum Gravity & Strings and Astrophysics, Cosmology & Gravity Center, Department of Mathematics & Applied Mathematics, University of Cape Town, Private Bag, Rondebosch 7701 (South Africa); National Institute for Theoretical Physics, Private Bag X1, Matieland, 7602 (South Africa); Soda, Jiro [Department of Physics, Kobe University, Kobe 657-8501 (Japan)

    2015-03-10

    We explore quantum entanglement between two causally disconnected regions in the multiverse. We first consider a free massive scalar field, and compute the entanglement negativity between two causally separated open charts in de Sitter space. The qualitative feature of it turns out to be in agreement with that of the entanglement entropy. We then introduce two observers who determine the entanglement between two causally disconnected de Sitter spaces. When one of the observers remains constrained to a region of the open chart in a de Sitter space, we find that the scale dependence enters into the entanglement. We show that a state which is initially maximally entangled becomes more entangled or less entangled on large scales depending on the mass of the scalar field and recovers the initial entanglement in the small scale limit. We argue that quantum entanglement may provide some evidence for the existence of the multiverse.

  7. Entanglement negativity in the multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, Sugumi [Department of Theoretical Physics and History of Science, University of the Basque Country UPV/EHU, 48080 Bilbao (Spain); Shock, Jonathan P. [Laboratory for Quantum Gravity and Strings and Astrophysics, Cosmology and Gravity Center, Department of Mathematics and Applied Mathematics, University of Cape Town, Private Bag, Rondebosch 7701 (South Africa); Soda, Jiro, E-mail: sugumi.kanno@ehu.es, E-mail: jonathan.shock@uct.ac.za, E-mail: jiro@phys.sci.kobe-u.ac.jp [Department of Physics, Kobe University, Kobe 657-8501 (Japan)

    2015-03-01

    We explore quantum entanglement between two causally disconnected regions in the multiverse. We first consider a free massive scalar field, and compute the entanglement negativity between two causally separated open charts in de Sitter space. The qualitative feature of it turns out to be in agreement with that of the entanglement entropy. We then introduce two observers who determine the entanglement between two causally disconnected de Sitter spaces. When one of the observers remains constrained to a region of the open chart in a de Sitter space, we find that the scale dependence enters into the entanglement. We show that a state which is initially maximally entangled becomes more entangled or less entangled on large scales depending on the mass of the scalar field and recovers the initial entanglement in the small scale limit. We argue that quantum entanglement may provide some evidence for the existence of the multiverse.

  8. Congenital nystagmus and negative electroretinography

    Directory of Open Access Journals (Sweden)

    Roussi M

    2011-04-01

    Full Text Available Mirella Roussi, Hélène Dalens, Jean Jacques Marcellier, Franck BacinDepartment of Ophthalmology, Clermont-Ferrand University, Clermont-Ferrand, FranceAbstract: Congenital nystagmus is a pathologic oculomotor state appearing at about three to four months of age. The precise diagnosis requires detailed clinical examination and electrophysiological findings. This case report presents two male patients with congenital nystagmus examined longitudinally from the age of six months until 17-18 years of age. Clinical and electrophysiological protocols were detailed. The first results showed electronegative electroretinography in the two cases and examination combined with electroretinographic findings helped us to make the diagnosis of Congenital Night Stationary Blindness (CSNB. This diagnosis was confirmed by genetic studies. CSNB is interesting to study because through electrophysiological findings, it enables a better understanding of the physiology of neural transmission in the outer part of the retina.Keywords: Congenital nystagmus, negative electroretinography, congenital night stationary blindness

  9. Incisional Negative Pressure Wound Therapy

    DEFF Research Database (Denmark)

    Hyldig, Nana

    a randomised controlled trial in two tertiary and three teaching hospitals in three regions of Denmark, the Happy Belly Study, investigating the effectiveness of iNPWT in a population of obese women after caesarean section. The Happy Belly Study has demonstrated that prophylactic iNPWT significantly reduced......-risk population of obese women giving birth by caesarean section. The Happy Belly Study is ongoing and thus this thesis presents preliminary results based on data from the first two-thirds of the scheduled study participants. Nonetheless, the results in this thesis are convincing. Accordingly, i......Women with a pre-gestational body mass index (BMI) above 30 kg/m2 giving birth by caesarean section are at high risk of surgical wound infection compared with women with a BMI below 30 kg/m2. Incisional Negative Pressure Wound Therapy (iNPWT) is one strategy to reduce the rate of surgical wound...

  10. Negative screenings in Liouville theory

    CERN Document Server

    Schnittger, Jens

    1996-01-01

    We demonstrate how negative powers of screenings arise as a nonperturbative effect within the operator approach to Liouville theory. This explains the origin of the corresponding poles in the exact Liouville three point function proposed by Dorn/Otto and (\\hbox{Zamolodchikov })^2 (DOZZ) and leads to a consistent extension of the operator approach to arbitrary integer numbers of screenings of both types. The general Liouville three point function in this setting is computed without any analytic continuation procedure, and found to support the DOZZ conjecture. We point out the importance of the concept of free field expansions with adjustable monodromies - recently advocated by Petersen, Rasmussen and Yu - in the present context, and show that it provides a unifying interpretation for two types of previously constructed local observables.

  11. Mondialization: The negation of territory

    Directory of Open Access Journals (Sweden)

    Đorđević Dejan

    2007-01-01

    Full Text Available The main objective of this paper is to present some weaknesses and inconsistence of the mondialization/globalization concept, especially regarding obvious negation of territoriality as a principle and a crude reality of uneven spatial distribution of resources, wealth and population on global scale. The domination of the globalism and neo-liberalism in the spheres of economy, society, culture and even language leads toward greater differences, in such intensity that some authors describe it as a "clash of civilizations". Loosing territoriality means loosing "raison d’etre" of spatial planning. Some efforts to introduce participation as a planning solution for the beginning of the new century is actually a Trojan horse and a step in the wrong direction.

  12. Hyperbolic spaces are of strictly negative type

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Kokkendorff, Simon L.; Markvorsen, Steen

    2002-01-01

    We study finite metric spaces with elements picked from, and distances consistent with, ambient Riemannian manifolds. The concepts of negative type and strictly negative type are reviewed, and the conjecture that hyperbolic spaces are of strictly negative type is settled, in the affirmative....... The technique of the proof is subsequently applied to show that every compact manifold of negative type must have trivial fundamental group, and to obtain a necessary criterion for product manifolds to be of negative type....

  13. In vivo neutralization of naturally existing antibodies against linear alpha(1,3)-galactosidic carbohydrate epitopes by multivalent antigen presentation: a solution for the first hurdle of pig-to-human xenotransplantation.

    Science.gov (United States)

    Duthaler, Rudolf O; Ernst, Beat; Fischer, Reto; Katopodis, Andreas G; Kinzy, Willy; Marterer, Wolfgang; Oehrlein, Reinhold; Streiff, Markus B; Thoma, Gebhard

    2010-01-01

    Pig-to-human xenotransplantation of islet cells or of vascularized organs would offer a welcome treatment alternative for the ever-increasing number of patients with end-stage organ failure who are waiting for a suitable allograph. The main hurdle are preexisting antibodies, most of which are specific for 'Linear-B', carbohydrate epitopes terminated by the unbranched Gal-alpha(1,3)Gal disaccharide. These antibodies are responsible for the 'hyper-acute rejection' of the xenograft by complement mediated hemorrhage. For depletion of such antibodies we have developed an artificial injectable antigen, a glycopolymer (GAS914) with a charge neutral poly-lysine backbone (degree of polymerization n = 1000) and 25% of its side chains coupled to Linear-B-trisaccharide. With an average molecular weight of 400 to 500 kD, presenting 250 trisaccharide epitopes per molecule, this multivalent array binds anti-alphaGal antibodies with at least three orders of magnitude higher avidity on a per-saccharide basis than the monomeric epitope. In vivo experiments with non-human primates documented that rather low doses--1 to 5 mg/kg of GAS914 injected i.v.--efficiently reduce the load of anti-Linear-B antibodies quickly by at least 80%. This treatment can be repeated without any sensitization to GAS914. Interestingly, although the antibody levels start raising 12 h after injection, they do not reach pretreatment levels. The polymer is degraded and excreted within hours, with a minute fraction remaining in lymphoid tissue of anti-alphaGal producing animals only, probably binding to and inhibiting antibody-producing B-cells. The results of pig-to-non-human primate xenotransplantations established GAS914 as a relevant therapeutic option for pig-to-human transplantations as well. The synthesis of GAS914 was successfully scaled up to kg amounts needed for first clinical studies. Key was the use of galactosyl transferases and UDP-galactose for the synthesis of the trisaccharide.

  14. Hurdle technology to preserve the 'Golden' papaya post harvest quality;Metodos combinados para preservar a qualidade pos-colheita do mamao 'Golden' tipo exportacao

    Energy Technology Data Exchange (ETDEWEB)

    Molinari, Andrea Cristina Fialho, E-mail: molinari_af@yahoo.co

    2007-07-01

    significant differences among papayas submitted to different treatments. A synergism was verified on the techniques combination, with the best results obtained from the association of CP + PEabs + gamma-irradiation at 0.4 kGy, which reached a total storage period of 35 days. Thus, that is the post harvest hurdle technology recommend for exporting 'Golden' papayas to markets with quarantine restrictions to fruit-flies (author)

  15. The doubly negative matrix completion problem

    OpenAIRE

    Araújo, C. Mendes; Torregrosa, Juan R.; Urbano, Ana M.

    2005-01-01

    An $n\\times n$ matrix over the field of real numbers is a doubly negative matrix if it is symmetric, negative definite and entry-wise negative. In this paper, we are interested in the doubly negative matrix completion problem, that is when does a partial matrix have a doubly negative matrix completion. In general, we cannot guarantee the existence of such a completion. In this paper, we prove that every partial doubly negative matrix whose associated graph is a $p$-chorda...

  16. Negative ion sources for tandem accelerator

    International Nuclear Information System (INIS)

    Minehara, Eisuke

    1980-08-01

    Four kinds of negative ion sources (direct extraction Duoplasmatron ion source, radial extraction Penniing ion source, lithium charge exchange ion source and Middleton-type sputter ion source) have been installed in the JAERI tandem accelerator. The ion sources can generate many negative ions ranging from Hydrogen to Uranium with the exception of Ne, Ar, Kr, Xe and Rn. Discussions presented in this report include mechanisms of negative ion formation, electron affinity and stability of negative ions, performance of the ion sources and materials used for negative ion production. Finally, the author will discuss difficult problems to be overcome in order to get any negative ion sufficiently. (author)

  17. 14 CFR 23.943 - Negative acceleration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Negative acceleration. 23.943 Section 23... Negative acceleration. No hazardous malfunction of an engine, an auxiliary power unit approved for use in... the airplane is operated at the negative accelerations within the flight envelopes prescribed in § 23...

  18. 14 CFR 25.943 - Negative acceleration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Negative acceleration. 25.943 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.943 Negative acceleration. No... the negative accelerations within the flight envelopes prescribed in § 25.333. This must be shown for...

  19. On multiphase negative flash for ideal solutions

    DEFF Research Database (Denmark)

    Yan, Wei; Stenby, Erling Halfdan

    2012-01-01

    There is a recent interest to solve multiphase negative flash problems where the phase amounts can be negative for normal positive feed composition. Solving such a negative flash problem using successive substitution needs an inner loop for phase distribution calculation at constant fugacity...

  20. Hyperbolic spaces are of strictly negative type

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Kokkendorff, Simon L.; Markvorsen, Steen

    2002-01-01

    We study finite metric spaces with elements picked from, and distances consistent with, ambient Riemannian manifolds. The concepts of negative type and strictly negative type are reviewed, and the conjecture that hyperbolic spaces are of strictly negative type is settled, in the affirmative...

  1. Emphatic multiple negative expressions in Dutch

    NARCIS (Netherlands)

    Zeijlstra, H.

    2010-01-01

    Double Negation languages like Dutch and German still exhibit constructions, such as Dutch 'niemand niet' ‘nobody not’ or 'nooit geen' ‘nothing no’, that seem to have a Negative Concord reading. Since these constructions normally have an emphatic reading, they are called Emphatic Multiple Negative

  2. Negative creep in nickel base superalloys

    DEFF Research Database (Denmark)

    Dahl, Kristian Vinter; Hald, John

    2004-01-01

    Negative creep describes the time dependent contraction of a material as opposed to the elongation seen for a material experiencing normal creep behavior. Negative creep occurs because of solid state transformations that results in lattice contractions. For most applications negative creep will h...

  3. AMBIGUITY, NEGATION, AND C-COMMAND

    Directory of Open Access Journals (Sweden)

    Rerisson Cavalcante de Araújo

    2016-12-01

    Full Text Available In this paper, I analyze negative scope ambiguity in sentences with cause, temporal and purpose adjuncts, in which negation can take scope either over the predicate or over the adjunct. I discuss Huang (1982, Takubo (1985 and Johnston’s (1994 analyses, which propose that the ambiguity is derived from different c-command relations between negation and adjunct, due to an optionality of adjunction to VP or IP. Against this view, I show a set of facts which are problematic for any analysis based only in c-command, i.e., several syntactic contexts where negation should c-command the adjunct, but where the ambiguity surprisingly still holds. Based on this, I argue that c-command is a necessary, but not sufficient condition to establish negative scope. And I suggest that the availability of predicate negation and adjunct negation results from an optionality of the operation of Labeling in adjunction, according Hornstein and Nunes (2008.

  4. Factores determinantes de la utilización de instrumentos públicos para la gestión del riesgo en la industria vitivinícola chilena: un modelo logit binomial

    Directory of Open Access Journals (Sweden)

    Germán Lobos

    2008-12-01

    Full Text Available The main objective of this research was to identify the determining factors of the use of public instruments to manage risk in the Chilean wine industry. A binomial logistic regression model was proposed. Based on a survey of 104 viticulture and winemaking companies, a database was constructed between January and October 2007. The model was fitted using maximum likelihood estimation. The variables that turned out to be statistically significant were: risk of the wine price, availability of external consultancy and number of permanent workers. From the Public Management point of view, the main conclusion suggests that the use of public instruments could be increased if viticulturists and winemakers had more external counseling.

  5. Aplicação do modelo binomial na formação de preço de títulos de dívida corporativa no Brasil.

    Directory of Open Access Journals (Sweden)

    José Roberto Securato

    2008-05-01

    components such as call options, convertibility options, seniority and subordination to a Brazilian company. The major results consist of debt securities valuation and its comparison to secondary market prices in order to identify investments opportunities. The paper evaluated six debt securities which have secondary market prices and three of them presented prices above market, two of them were bellow market price and one of them had the same price of the market. The presented model and its adjustments to Brazilian market allow evaluating corporate debt securities and its components, evaluating the impact of new debt issues in the existing ones and comparing debt model and book values. Keywords: binomial model; corporate debt; debt components.

  6. Analysis of False-Negative Human Immunodeficiency Virus Rapid Tests Performed on Oral Fluid in 3 International Clinical Research Studies.

    Science.gov (United States)

    Curlin, Marcel E; Gvetadze, Roman; Leelawiwat, Wanna; Martin, Michael; Rose, Charles; Niska, Richard W; Segolodi, Tebogo M; Choopanya, Kachit; Tongtoyai, Jaray; Holtz, Timothy H; Samandari, Taraz; McNicholl, Janet M

    2017-06-15

    The OraQuick Advance Rapid HIV-1/2 Test is a point-of-care test capable of detecting human immunodeficiency virus (HIV)-specific antibodies in blood and oral fluid. To understand test performance and factors contributing to false-negative results in longitudinal studies, we examined results of participants enrolled in the Botswana TDF/FTC Oral HIV Prophylaxis Trial, the Bangkok Tenofovir Study, and the Bangkok MSM Cohort Study, 3 separate clinical studies of high-risk, HIV-negative persons conducted in Botswana and Thailand. In a retrospective observational analysis, we compared oral fluid OraQuick (OFOQ) results among participants becoming HIV infected to results obtained retrospectively using enzyme immunoassay and nucleic acid amplification tests on stored specimens. We categorized negative OFOQ results as true-negative or false-negative relative to nucleic acid amplification test and/or enzyme immunoassay, and determined the delay in OFOQ conversion relative to the estimated time of infection. We used log-binomial regression and generalized estimating equations to examine the association between false-negative results and participant, clinical, and testing-site factors. Two-hundred thirty-three false-negative OFOQ results occurred in 80 of 287 seroconverting individuals. Estimated OFOQ conversion delay ranged from 14.5 to 547.5 (median, 98.5) days. Delayed OFOQ conversion was associated with clinical site and test operator (P < .05), preexposure prophylaxis (P = .01), low plasma viral load (P < .02), and time to kit expiration (P < .01). Participant age, sex, and HIV subtype were not associated with false-negative results. Long OFOQ conversion delay time was associated with antiretroviral exposure and low plasma viral load. Failure of OFOQ to detect HIV-1 infection was frequent and multifactorial in origin. In longitudinal trials, negative oral fluid results should be confirmed via testing of blood samples. Published by Oxford University Press for the

  7. A non-linear beta-binomial regression model for mapping EORTC QLQ- C30 to the EQ-5D-3L in lung cancer patients: a comparison with existing approaches.

    Science.gov (United States)

    Khan, Iftekhar; Morris, Stephen

    2014-11-12

    The performance of the Beta Binomial (BB) model is compared with several existing models for mapping the EORTC QLQ-C30 (QLQ-C30) on to the EQ-5D-3L using data from lung cancer trials. Data from 2 separate non small cell lung cancer clinical trials (TOPICAL and SOCCAR) are used to develop and validate the BB model. Comparisons with Linear, TOBIT, Quantile, Quadratic and CLAD models are carried out. The mean prediction error, R(2), proportion predicted outside the valid range, clinical interpretation of coefficients, model fit and estimation of Quality Adjusted Life Years (QALY) are reported and compared. Monte-Carlo simulation is also used. The Beta-Binomial regression model performed 'best' among all models. For TOPICAL and SOCCAR trials, respectively, residual mean square error (RMSE) was 0.09 and 0.11; R(2) was 0.75 and 0.71; observed vs. predicted means were 0.612 vs. 0.608 and 0.750 vs. 0.749. Mean difference in QALY's (observed vs. predicted) were 0.051 vs. 0.053 and 0.164 vs. 0.162 for TOPICAL and SOCCAR respectively. Models tested on independent data show simulated 95% confidence from the BB model containing the observed mean more often (77% and 59% for TOPICAL and SOCCAR respectively) compared to the other models. All algorithms over-predict at poorer health states but the BB model was relatively better, particularly for the SOCCAR data. The BB model may offer superior predictive properties amongst mapping algorithms considered and may be more useful when predicting EQ-5D-3L at poorer health states. We recommend the algorithm derived from the TOPICAL data due to better predictive properties and less uncertainty.

  8. Binomial outcomes in dataset with some clusters of size two: can the dependence of twins be accounted for? A simulation study comparing the reliability of statistical methods based on a dataset of preterm infants.

    Science.gov (United States)

    Sauzet, Odile; Peacock, Janet L

    2017-07-20

    The analysis of perinatal outcomes often involves datasets with some multiple births. These are datasets mostly formed of independent observations and a limited number of clusters of size two (twins) and maybe of size three or more. This non-independence needs to be accounted for in the statistical analysis. Using simulated data based on a dataset of preterm infants we have previously investigated the performance of several approaches to the analysis of continuous outcomes in the presence of some clusters of size two. Mixed models have been developed for binomial outcomes but very little is known about their reliability when only a limited number of small clusters are present. Using simulated data based on a dataset of preterm infants we investigated the performance of several approaches to the analysis of binomial outcomes in the presence of some clusters of size two. Logistic models, several methods of estimation for the logistic random intercept models and generalised estimating equations were compared. The presence of even a small percentage of twins means that a logistic regression model will underestimate all parameters but a logistic random intercept model fails to estimate the correlation between siblings if the percentage of twins is too small and will provide similar estimates to logistic regression. The method which seems to provide the best balance between estimation of the standard error and the parameter for any percentage of twins is the generalised estimating equations. This study has shown that the number of covariates or the level two variance do not necessarily affect the performance of the various methods used to analyse datasets containing twins but when the percentage of small clusters is too small, mixed models cannot capture the dependence between siblings.

  9. Binomial outcomes in dataset with some clusters of size two: can the dependence of twins be accounted for? A simulation study comparing the reliability of statistical methods based on a dataset of preterm infants

    Directory of Open Access Journals (Sweden)

    Odile Sauzet

    2017-07-01

    Full Text Available Abstract Background The analysis of perinatal outcomes often involves datasets with some multiple births. These are datasets mostly formed of independent observations and a limited number of clusters of size two (twins and maybe of size three or more. This non-independence needs to be accounted for in the statistical analysis. Using simulated data based on a dataset of preterm infants we have previously investigated the performance of several approaches to the analysis of continuous outcomes in the presence of some clusters of size two. Mixed models have been developed for binomial outcomes but very little is known about their reliability when only a limited number of small clusters are present. Methods Using simulated data based on a dataset of preterm infants we investigated the performance of several approaches to the analysis of binomial outcomes in the presence of some clusters of size two. Logistic models, several methods of estimation for the logistic random intercept models and generalised estimating equations were compared. Results The presence of even a small percentage of twins means that a logistic regression model will underestimate all parameters but a logistic random intercept model fails to estimate the correlation between siblings if the percentage of twins is too small and will provide similar estimates to logistic regression. The method which seems to provide the best balance between estimation of the standard error and the parameter for any percentage of twins is the generalised estimating equations. Conclusions This study has shown that the number of covariates or the level two variance do not necessarily affect the performance of the various methods used to analyse datasets containing twins but when the percentage of small clusters is too small, mixed models cannot capture the dependence between siblings.

  10. Negative Pressure Wound Therapy in Maxillofacial Applications

    Directory of Open Access Journals (Sweden)

    Adam J. Mellott

    2016-09-01

    Full Text Available Negative pressure wound therapy has greatly advanced the field of wound healing for nearly two decades, by providing a robust surgical adjunct technique for accelerating wound closure in acute and chronic wounds. However, the application of negative pressure wound therapy in maxillofacial applications has been relatively under utilized as a result of the physical articulations and contours of the head and neck that make it challenging to obtain an airtight seal for different negative pressure wound therapy systems. Adapting negative pressure wound therapies for maxillofacial applications could yield significant enhancement of wound closure in maxillofacial applications. The current review summarizes the basic science underlying negative pressure wound therapy, as well as specific maxillofacial procedures that could benefit from negative pressure wound therapy.

  11. Analyzing negative ties in social networks

    Directory of Open Access Journals (Sweden)

    Mankirat Kaur

    2016-03-01

    Full Text Available Online social networks are a source of sharing information and maintaining personal contacts with other people through social interactions and thus forming virtual communities online. Social networks are crowded with positive and negative relations. Positive relations are formed by support, endorsement and friendship and thus, create a network of well-connected users whereas negative relations are a result of opposition, distrust and avoidance creating disconnected networks. Due to increase in illegal activities such as masquerading, conspiring and creating fake profiles on online social networks, exploring and analyzing these negative activities becomes the need of hour. Usually negative ties are treated in same way as positive ties in many theories such as balance theory and blockmodeling analysis. But the standard concepts of social network analysis do not yield same results in respect of each tie. This paper presents a survey on analyzing negative ties in social networks through various types of network analysis techniques that are used for examining ties such as status, centrality and power measures. Due to the difference in characteristics of flow in positive and negative tie networks some of these measures are not applicable on negative ties. This paper also discusses new methods that have been developed specifically for analyzing negative ties such as negative degree, and h∗ measure along with the measures based on mixture of positive and negative ties. The different types of social network analysis approaches have been reviewed and compared to determine the best approach that can appropriately identify the negative ties in online networks. It has been analyzed that only few measures such as Degree and PN centrality are applicable for identifying outsiders in network. For applicability in online networks, the performance of PN measure needs to be verified and further, new measures should be developed based upon negative clique concept.

  12. Art, Terrorism and the Negative Sublime

    Directory of Open Access Journals (Sweden)

    Arnold Berleant

    2009-01-01

    Full Text Available The range of the aesthetic has expanded to cover not only a wider range of objects and situations of daily life but also to encompass the negative. This includes terrorism, whose aesthetic impact is central to its use as a political tactic. The complex of positive and negative aesthetic values in terrorism are explored, introducing the concept of the sublime as a negative category to illuminate the analysis and the distinctive aesthetic of terrorism.

  13. Engineered endolysin-based "Artilysins" to combat multidrug-resistant gram-negative pathogens.

    Science.gov (United States)

    Briers, Yves; Walmagh, Maarten; Van Puyenbroeck, Victor; Cornelissen, Anneleen; Cenens, William; Aertsen, Abram; Oliveira, Hugo; Azeredo, Joana; Verween, Gunther; Pirnay, Jean-Paul; Miller, Stefan; Volckaert, Guido; Lavigne, Rob

    2014-07-01

    The global threat to public health posed by emerging multidrug-resistant bacteria in the past few years necessitates the development of novel approaches to combat bacterial infections. Endolysins encoded by bacterial viruses (or phages) represent one promising avenue of investigation. These enzyme-based antibacterials efficiently kill Gram-positive bacteria upon contact by specific cell wall hydrolysis. However, a major hurdle in their exploitation as antibacterials against Gram-negative pathogens is the impermeable lipopolysaccharide layer surrounding their cell wall. Therefore, we developed and optimized an approach to engineer these enzymes as outer membrane-penetrating endolysins (Artilysins), rendering them highly bactericidal against Gram-negative pathogens, including Pseudomonas aeruginosa and Acinetobacter baumannii. Artilysins combining a polycationic nonapeptide and a modular endolysin are able to kill these (multidrug-resistant) strains in vitro with a 4 to 5 log reduction within 30 min. We show that the activity of Artilysins can be further enhanced by the presence of a linker of increasing length between the peptide and endolysin or by a combination of both polycationic and hydrophobic/amphipathic peptides. Time-lapse microscopy confirmed the mode of action of polycationic Artilysins, showing that they pass the outer membrane to degrade the peptidoglycan with subsequent cell lysis. Artilysins are effective in vitro (human keratinocytes) and in vivo (Caenorhabditis elegans). Importance: Bacterial resistance to most commonly used antibiotics is a major challenge of the 21st century. Infections that cannot be treated by first-line antibiotics lead to increasing morbidity and mortality, while millions of dollars are spent each year by health care systems in trying to control antibiotic-resistant bacteria and to prevent cross-transmission of resistance. Endolysins--enzymes derived from bacterial viruses--represent a completely novel, promising class of

  14. Negative creep in nickel base superalloys

    DEFF Research Database (Denmark)

    Dahl, Kristian Vinter; Hald, John

    2004-01-01

    Negative creep describes the time dependent contraction of a material as opposed to the elongation seen for a material experiencing normal creep behavior. Negative creep occurs because of solid state transformations that results in lattice contractions. For most applications negative creep...... will have no practical implications but under certain conditions it may become critical. For bolts and fasteners, which are highly constrained during service, negative creep may lead to dramatically increased stresses and eventually to failure. The article was inspired by a recent failure of Nimonic 80A...

  15. Brilliant but Cruel: Perceptions of Negative Evaluators.

    Science.gov (United States)

    Amabile, Teresa M.

    Two studies examined the hypothesis that negative evaluators will be perceived as more intelligent than positive evalutors. Two types of stimuli were used: excerpts from actual negative and positive book reviews, and versions of those excerpts that were edited so that the balance of the reviews varied but the content did not. The results strongly…

  16. Bootstrapping Visual Categorization with Relevant Negatives

    NARCIS (Netherlands)

    Li, X.; Snoek, C.G.M.; Worring, M.; Koelma, D.; Smeulders, A.W.M.

    Learning classifiers for many visual concepts are important for image categorization and retrieval. As a classifier tends to misclassify negative examples which are visually similar to positive ones, inclusion of such misclassified and thus relevant negatives should be stressed during learning.

  17. A Negative Permeability Material at Red Light

    DEFF Research Database (Denmark)

    Yuan, Hsiao-Kuan; Chettiar, Uday K.; Cai, Wenshan

    2007-01-01

    A negative permeability in a periodic array of pairs of thin silver strips is demonstrated experimentally for two distinct samples. The effect of the strip surface roughness on negative permeability is evaluated. The first sample, Sample A, is fabricated of thinner strips with a root mean square ...

  18. Negative Automaintenance Omission Training Is Effective

    Science.gov (United States)

    Sanabria, Federico; Sitomer, Matthew T.; Killeen, Peter R.

    2006-01-01

    Twelve pigeons were exposed to negative automaintenance contingencies for 17-27 sessions immediately after brief (14-16 sessions) or extended (168-237 sessions) exposure to positive automaintenance contingencies, or after 4-10 sessions of instrumental training. In all conditions, negative automaintenance contingencies virtually eliminated…

  19. Aspects of Negation in Classical Greek.

    Science.gov (United States)

    Taylor, Daniel J.

    1972-01-01

    Traditional grammars are criticized as having obscured or omitted many significant features of negation patterns in classical Greek. The author demonstrates that negation in Greek extensively involves semantic and syntactic factors. Certain of the factors are thoroughly embedded in the traditional approach to grammar, while others are derived from…

  20. Negative social effects of global business

    Directory of Open Access Journals (Sweden)

    Milanović-Golubović Vesna

    2008-01-01

    Full Text Available This paper wants to prove that negative social effects of global business are reasons for growing social welfare. Negative social effects of global business are reflected through the rise of unemployment, fall of life standard and decrease of life quality and culture, particularly in less developed societies.