20 research outputs found
Local Admissibility and Local Unbiasedness in Hypothesis Testing Problems
In this paper we give necessary conditions and sufficient conditions for a test to be locally unbiased, we define local admissibility and we characterize local admissibility in hypothesis testing problems with simple null hypotheses. Applications are presented involving same-sign alternatives, ordered alternatives and independence testing of several variables
Complete Class Results for Hypothesis Testing Problems With Simple Null Hypotheses
Hypothesis testing problems in which the null hypothesis is simple, the parameter space is finite dimensional and the supports of the probability measures are independent of the parameter are considered. Essentially complete class results are obtained for characterizing the limits of Bayes tests. Conditions for tests to be admissible and the class to be complete are given. Results are then specialized to exponential families, along with some illustrative examples
Characterizations, Sub and Resampling, and Goodness of Fit
We present a general proposal for testing for goodness of fit, based on resampling and subsampling methods, and illustrate it with graphical and analytical tests for the problems of testing for univariate or multivariate normality. The proposal shows promising, and in some cases dramatic, success in detecting nonnormality. Compared to common competitors, such as a Q-Q plot or a likelihood ratio test against a specified alternative, our proposal seems to be the most useful when the sample size is small, such as 10 or 12, or even very small, such as 6! We also show how our proposal provides tangible information about the nature of the true cdf from which one is sampling. Thus, our proposal also has data analytic value. Although only the normality problem is addressed here, the scope of application of the general proposal should be much broader
Relationships between Water Quality and Corrosion of Plumbing Materials in Buildings
published or submitted for publicationis peer reviewedOpe
Glomerulocystic kidney disease
Glomerulocystic disease is a rare renal cystic disease with a long descriptive history. Findings from recent studies have significantly advanced the pathophysiological understanding of the disease processes leading to this peculiar phenotype. Many genetic syndromes associated with glomerulocystic disease have had their respective proteins localized to primary cilia or centrosomes. Transcriptional control of renal developmental pathways is dysregulated in obstructive diseases that also lead to glomerulocystic disease, emphasizing the importance of transcriptional choreography between renal development and renal cystic disease
The significance of genome-wide transcriptional regulation in the evolution of stress tolerance.
It is widely recognized that stress plays an important role in directing the adaptive adjustment of an organism to changing environments. However, very little is known about the evolution of mechanisms that promote stress-induced variation. Adaptive transcriptional responses have been implicated in the evolution of tolerance to natural and anthropogenic stressors in the environment. Recent technological advances in transcriptomics provide a mechanistic understanding of biological pathways or processes involved in stress-induced phenotypic change. Furthermore, these studies are (semi) quantitative and provide insight into the reaction norms of identified target genes in response to specific stressors. We argue that plasticity in gene expression reaction norms may be important in the evolution of stress tolerance and adaptation to environmental stress. This review highlights the consequences of transcriptional plasticity of stress responses within a single generation and concludes that gene promoters containing a TATA box are more capable of rapid and variable responses than TATA-less genes. In addition, the consequences of plastic transcriptional responses to stress over multiple generations are discussed. Based on examples from the literature, we show that constitutive over expression of specific stress response genes results in stress adapted phenotypes. However, organisms with an innate capacity to buffer stress display plastic transcriptional responses. Finally, we call for an improved integration of the concept of phenotypic plasticity with studies that focus on the regulation of transcription. © Springer Science+Business Media B.V. 2010
Some robust estimates of principal components
Robust estimates of principal components are developed using appropriate definitions of multivariate signs and ranks. Simulations and a data example are used to compare these methods to the regular method and one based on the minimum-volume-ellipsoid estimate of the covariance matrix. The sign and rank procedures are quite robust unless there is severe contamination, in which case the minimum-volume-ellipsoid estimate is preferable.Principal components Multivariate analysis Multivariate ranks Multivariate signs Robust estimation Minimum-volume-ellipsoid estimator