A stochastic model for the analysis of bivariate longitudinal AIDS data.

abstract：:We introduce a nearly automatic procedure to locate and count the quantum dots in images of kinesin motor assays. Our procedure employs an approximate likelihood estimator based on a two-component mixture model for the image data; the first component has a normal distribution, and the other component is distributed as...

journal_title：Biometrics

authors： Hughes J,Fricks J

更新日期：2011-06-01 00:00:00

abstract：:In a period starting around 2007, the Hand, Foot, and Mouth Disease (HFMD) became wide-spreading in China, and the Chinese public health was seriously threatened. To prevent the outbreak of infectious diseases like HFMD, effective disease surveillance systems would be especially helpful to give signals of disease outb...

journal_title：Biometrics

authors： Zhang J,Kang Y,Yang Y,Qiu P

更新日期：2015-09-01 00:00:00

abstract：:We consider a semiparametric regression model that relates a normal outcome to covariates and a genetic pathway, where the covariate effects are modeled parametrically and the pathway effect of multiple gene expressions is modeled parametrically or nonparametrically using least-squares kernel machines (LSKMs). This un...

journal_title：Biometrics

authors： Liu D,Lin X,Ghosh D

更新日期：2007-12-01 00:00:00

abstract：:Five procedures are considered for the comparison of two or more multivariate samples. These procedures include a newly proposed nonparametric rank-sum test and a generalized least squares test. Also considered are the following tests: ordinary least squares, Hotelling's T2, and a Bonferroni per-experiment error-rate ...

journal_title：Biometrics

authors： O'Brien PC

更新日期：1984-12-01 00:00:00

abstract：:We derive a likelihood score method for interval estimation of the intraclass version of the kappa coefficient of agreement with binary classification using a general theory of Bartlett (1953, Biometrika 40, 306-317). By exact evaluation, we investigate statistical properties of the score method, the chi-square goodne...

journal_title：Biometrics

authors： Nam JM

更新日期：2000-06-01 00:00:00

abstract：:Traditional paradigms for clinical translation are challenged in settings where multiple contemporaneous therapeutic strategies have been identified as potentially beneficial. Platform trials have emerged as an approach for sequentially comparing multiple trials using a single protocol. The Ebola virus disease outbrea...

journal_title：Biometrics

authors： Kaizer AM,Hobbs BP,Koopmeiners JS

更新日期：2018-09-01 00:00:00

abstract：:We consider a two-sample problem where data come from symmetric distributions. Usual two-sample data with only magnitudes recorded, arising from case-control studies or logistic discriminant analyses, may constitute a symmetric two-sample problem. We propose a semiparametric model such that, in addition to symmetry, t...

journal_title：Biometrics

authors： Li M,Diao G,Qin J

更新日期：2020-12-01 00:00:00

abstract：:In this note we propose a frailty model called piecewise gamma frailty for correlated survival data with random effects having a nested structure. In frailty models, a dependence function defined as a hazard ratio of one member given the failure time of another member in a unit is determined by the distributional assu...

journal_title：Biometrics

authors： Paik MC,Tsai WY,Ottman R

更新日期：1994-12-01 00:00:00

abstract：:Mixed latent Markov (MLM) models represent an important tool of analysis of longitudinal data when response variables are affected by time-fixed and time-varying unobserved heterogeneity, in which the latter is accounted for by a hidden Markov chain. In order to avoid bias when using a model of this type in the presen...

journal_title：Biometrics

authors： Bartolucci F,Farcomeni A

更新日期：2015-03-01 00:00:00

abstract：:Advances in sequencing technologies and bioinformatics tools have vastly improved our ability to collect and analyze data from complex microbial communities. A major goal of microbiome studies is to correlate the overall microbiome composition with clinical or environmental variables. La Rosa et al. recently proposed ...

journal_title：Biometrics

authors： Song Y,Zhao H,Wang T

更新日期：2020-06-01 00:00:00

abstract：:Logistic regression is a popular tool for risk analysis in medical and population health science. With continuous response data, it is common to create a dichotomous outcome for logistic regression analysis by specifying a threshold for positivity. Fitting a linear regression to the nondichotomized response variable a...

journal_title：Biometrics

authors： Schörgendorfer A,Branscum AJ,Hanson TE

更新日期：2013-06-01 00:00:00

abstract：:Multiple outcomes are often used to properly characterize an effect of interest. This paper proposes a latent variable model for the situation where repeated measures over time are obtained on each outcome. These outcomes are assumed to measure an underlying quantity of main interest from different perspectives. We re...

journal_title：Biometrics

authors： Roy J,Lin X

更新日期：2000-12-01 00:00:00

abstract：:The paper here presented was motivated by a case study involving high-dimensional and high-frequency tidal volume traces measured during induced panic attacks. The focus was to develop a procedure to determine the significance of whether a mean curve dominates another one. The key idea of the suggested method relies o...

journal_title：Biometrics

authors： Lee SH,Lim J,Vannucci M,Petkova E,Preter M,Klein DF

更新日期：2008-09-01 00:00:00

abstract：:This article develops a variety of influence measures for carrying out perturbation (or sensitivity) analysis to joint models of longitudinal and survival data (JMLS) in Bayesian analysis. A perturbation model is introduced to characterize individual and global perturbations to the three components of a Bayesian model...

journal_title：Biometrics

authors： Zhu H,Ibrahim JG,Chi YY,Tang N

更新日期：2012-09-01 00:00:00

abstract：:Alterations in DNA methylation have been linked to the development and progression of many diseases. The bisulfite sequencing technique presents methylation profiles at base resolution. Count data on methylated and unmethylated reads provide information on the methylation level at each CpG site. As more bisulfite sequ...

journal_title：Biometrics

authors： Ji T

更新日期：2019-06-01 00:00:00

abstract：:The risks of conception, due to sexual intercourse at various times before and after the periovulatory rise in the woman's basal body temperature, are evaluated. In general, the risk is small nine or more days before, and two or more days after, the first day of elevated temperature. The model for the conception proba...

journal_title：Biometrics

authors： Royston JP

更新日期：1982-06-01 00:00:00

abstract：:Dynamic treatment regimes (DTRs) aim to formalize personalized medicine by tailoring treatment decisions to individual patient characteristics. G-estimation for DTR identification targets the parameters of a structural nested mean model, known as the blip function, from which the optimal DTR is derived. Despite its po...

journal_title：Biometrics

authors： Wallace MP,Moodie EEM,Stephens DA

更新日期：2019-12-01 00:00:00

abstract：:Estimating the number of clusters in a data set is a crucial step in cluster analysis. In this article, motivated by the gap method (Tibshirani, Walther, and Hastie, 2001, Journal of the Royal Statistical Society B63, 411-423), we propose the weighted gap and the difference of difference-weighted (DD-weighted) gap met...

journal_title：Biometrics

authors： Yan M,Ye K

更新日期：2007-12-01 00:00:00

abstract：:The fitting of finite mixture models via the EM algorithm is considered for data which are available only in grouped form and which may also be truncated. A practical example is presented where a mixture of two doubly truncated log-normal distributions is adopted to model the distribution of the volume of red blood ce...

journal_title：Biometrics

authors： McLachlan GJ,Jones PN

更新日期：1988-06-01 00:00:00

abstract：SUMMARY:Nonparametric regression models are proposed in the framework of ecological inference for exploratory modeling of disease prevalence rates adjusted for variables, such as age, ethnicity/race, and socio-economic status. Ecological inference is needed when a response variable and covariate are not available at th...

journal_title：Biometrics

authors： Staniswalis JG

更新日期：2008-12-01 00:00:00

abstract：:A common measure in clinical trials and epidemiologic studies is the number of events such as seizures, hospitalizations, or bouts of disease. Frequently, a binary measure of severity for each event is available but is not incorporated in the analysis. This paper proposes methodology for jointly modeling the number of...

journal_title：Biometrics

authors： Albert PS,Follmann DA,Barnhart HX

更新日期：1997-09-01 00:00:00

abstract：:Normality of random effects is a routine assumption for the linear mixed model, but it may be unrealistic, obscuring important features of among-individual variation. We relax this assumption by approximating the random effects density by the seminonparameteric (SNP) representation of Gallant and Nychka (1987, Econome...

journal_title：Biometrics

authors： Zhang D,Davidian M

更新日期：2001-09-01 00:00:00

abstract：:We develop a parameterization of the beta-binomial mixture that provides sensible inferences about the size of a closed population when probabilities of capture or detection vary among individuals. Three classes of mixture models (beta-binomial, logistic-normal, and latent-class) are fitted to recaptures of snowshoe h...

journal_title：Biometrics

authors： Dorazio RM,Royle JA

更新日期：2003-06-01 00:00:00

abstract：:This article considers sieve estimation in the Cox model with an unknown regression structure based on right-censored data. We propose a semiparametric pursuit method to simultaneously identify and estimate linear and nonparametric covariate effects based on B-spline expansions through a penalized group selection meth...

journal_title：Biometrics

authors： Cao Y,Huang J,Liu Y,Zhao X

更新日期：2016-12-01 00:00:00

abstract：:In practice, when analyzing data from a capture-recapture experiment it is tempting to apply modern advanced statistical methods to the observed capture histories. However, unless the analysis takes into account that the data have only been collected from individuals who have been captured at least once, the results m...

journal_title：Biometrics

authors： Stoklosa J,Hwang WH,Wu SH,Huggins R

更新日期：2011-12-01 00:00:00

abstract：:Given data from bilateral visual assessments on N subjects at k occasions, we consider inference for contralateral correlations (C) between fellow eyes and lateral correlations (L) among p different assessments of the same eye. Under permutation symmetric dependence structure between observations from fellow eyes and ...

journal_title：Biometrics

authors： Viana M,Olkin I

更新日期：2000-12-01 00:00:00

abstract：:Treatments are frequently evaluated in terms of their effect on patient survival. In settings where randomization of treatment is not feasible, observational data are employed, necessitating correction for covariate imbalances. Treatments are usually compared using a hazard ratio. Most existing methods which quantify ...

journal_title：Biometrics

authors： Gong Q,Schaubel DE

更新日期：2017-03-01 00:00:00

abstract：:Assuming a model of proportional failure rates, Cox (1972) presents a systematic study of the use of covariates in the analysis of life time. The treatment of tied observations is a particularly troublesome point in both theory and application. It appears that grouping rather than discrete time is the right way to han...

journal_title：Biometrics

authors： Thompson WA Jr

更新日期：1977-09-01 00:00:00

abstract：:Statistical models that include random effects are commonly used to analyze longitudinal and correlated data, often with the assumption that the random effects follow a Gaussian distribution. Via theoretical and numerical calculations and simulation, we investigate the impact of misspecification of this distribution o...

journal_title：Biometrics

authors： McCulloch CE,Neuhaus JM

更新日期：2011-03-01 00:00:00

abstract：:It has become increasingly common in epidemiological studies to pool specimens across subjects to achieve accurate quantitation of biomarkers and certain environmental chemicals. In this article, we consider the problem of fitting a binary regression model when an important exposure is subject to pooling. We take a re...

journal_title：Biometrics

authors： Zhang Z,Albert PS

更新日期：2011-06-01 00:00:00