The purpose of this study was to investigate and analyse the fracture toughness of yttria stabilized tetragonal zirconia polycrystal (Y-TZP) dental ceramics by means of the Vickers indentation technique. Fracture toughness was analysed under the following loads: 29.42 N, 49.03 N, 196.13 N, and 294.20 N. Cracks that had developed from the vertices of a Vickers indentation were measured and used ...

Biomarker data is often subject to limits of quantification and/or limits of detection. Statistically, this corresponds to leftor interval-censoring. To be able to associate a censored time-to-event endpoint to a biomarker covariate, the R package SurvRegCensCov provides software for Weibull regression for a right-censored endpoint, one intervalcensored, and an arbitrary number of non-censored ...

Standard lifetime distributions usually very place strong restrictions on the data as is well illustrated by their inability to produce bathtub curves, and thus to adequately interpret data with this character. Mudholkar et al. (1995) introduced the exponentiated-Weibull distribution and Xie et al. (2002) proposed the new Weibull extension distribution. The new Weibull extension distribution wi...

Interval censored outcomes arise when a silent event of interest is known to have occurred within a specific time period determined by the times of the last negative and first positive diagnostic tests. There is a rich literature on parametric and non-parametric approaches for the analysis of interval-censored outcomes. A commonly used strategy is to use a proportional hazards (PH) model with t...

In this paper, we present a Weibull link (skewed) model for categorical response data arising from binomial as well as multinomial model. We show that, for such types of categorical data, the most commonly used models (logit, probit and complementary log–log) can be obtained as limiting cases. We further compare the proposed model with some other asymmetrical models. The Bayesian as well as fre...

Diagnostic methods have been an important tool in regression analysis to detect anomalies, such as departures from the error assumptions and the presence of outliers and influential observations with the fitted models. The literature provides plenty of approaches for detecting outlying or influential observations in data sets. In this paper, we follow the local influence approach (Cook 1986) in...

purpose: to evaluate the effect of age, sex, type of surgery, extent of retinal detachment (rd), vitreous incarceration in wound, and myopic degeneration on the rate of retinal redetachment following rd surgery using eternal weibull regression analysis. methods: we performed a survival analysis on a multi-center randomized controlled trial conducted on patients with pseudophakic or aphakic rd t...

Standard quantitative trait loci (QTL) mapping techniques commonly assume that the trait is both fully observed and normally distributed. When considering survival or age-at-onset traits these assumptions are often incorrect. Methods have been developed to map QTL for survival traits; however, they are both computationally intensive and not available in standard genome analysis software package...