Estimation of prediction error variances via Monte Carlo sampling methods using different formulations of the prediction error variance

Calculation of the exact prediction error variance covariance matrix is often computationally too demanding, which limits its application in REML algorithms, the calculation of accuracies of estimated breeding values and the control of variance of response to selection. Alternatively Monte Carlo sampling can be used to calculate approximations of the prediction error variance, which converge to the true values if enough samples are used. However, in practical situations the number of samples, which are computationally feasible, is limited. The objective of this study was to compare the convergence rate of different formulations of the prediction error variance calculated using Monte Carlo sampling. Four of these formulations were published, four were corresponding alternative versions, and two were derived as part of this study. The different formulations had different convergence rates and these were shown to depend on the number of samples and on the level of prediction error variance. Four formulations were competitive and these made use of information on either the variance of the estimated breeding value and on the variance of the true breeding value minus the estimated breeding value or on the covariance between the true and estimated breeding values

Customer experience, satisfaction and brand relevance : a South African grocery retail context perspective

Abstract: Retailers often compete in the market by focusing on achieving customer satisfaction by providing good in-store shopping experiences. South African shoppers are however argued to be very brand conscious, and therefore, the relevance of a retail brand may in addition influence this experience and satisfaction relationship. This study seeks to uncover the relationship between customer experience and customer satisfaction and explores the moderating role of brand relevance on the relationship between customer experience and satisfaction. Using a quantitative approach, a total of 395 responses were collected from South African grocery retail shoppers. An SEM analysis is conducted with the variables “Sense”, “Think” and “Feel” as the predictors of customer experience, and their resulting influence on customer satisfaction tested. The variable “Think” was the only experience variable that had a significant influence on customers’ satisfaction levels, whilst “Brand relevance” demonstrated potential as a predictor of customer satisfaction, rather than a moderator between experience and satisfaction

The interobserver and test-retest variability of the dysphonia severity index

Objective: The purpose of this study was to investigate the interobserver variability and the test-retest variability of the Dysphonia Severity Index (DSI), a multiparametric instrument to assess voice quality. Methods: The DSI was measured in 30 nonsmoking volunteers without voice complaints or voice disorders by two speech pathologists. The subjects were measured on 3 different days, with an interval of 1 week. Results: The difference in DSI between two observers (interobserver difference) was not significant. The intraclass correlation coefficient for the DSI was 0.79. The standard deviation of the difference between two duplicate measurements by different observers was 1.27. Conclusion: Differences in measurements between different observers were not significant. The intraclass correlation coefficient of the DSI was 0.79, which is to be considered good. Differences in DSI within one patient need to be larger than 2.49 to be significant. Copyrigh

A Case of Autoimmune Hepatitis and Bisphosphonate-Related Osteonecrosis of the Jaw

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease of unknown aetiology usually requiring long-term immunosuppressive therapy. We present the case of an AIH patient who received long-term corticosteroids and azathioprine. As treatment for concomitant osteoporosis she was also treated with potent intravenous bisphosphonate (BP). This treatment was complicated by the development of BP-related osteonecrosis of the jaw (BRONJ). BRONJ is an uncommon complication of BP treatment regimes that occurs at increased frequency in the presence of other risk factors, including chronic inflammatory conditions. Our patient suffered from a severe and complicated clinical course of BRONJ which, despite adequate therapy, resulted in death of the patient. Here we discuss the risk factors for the development and clinical course of BRONJ in AIH and the implications for management of these patients

N- and KRAS mutations in primary testicular germ cell tumors: Incidence and possible biological implications

Recently, conflicting results have been reported on the incidence of RAS mutations in primary testicular germ cell tumors of adults (TGCTs). In four studies a low incidence of mutations (less than 15%) in a variety of TGCTs or derived cell lines was found, whereas in two other studies a high incidence of N- or KRAS mutations (over 40%) was shown. A total of 62 testicular seminomas (SE) and 34 nonseminomatous TGCTs (NS) were studied thus far. The largest series consisted of 42 TGCTs, studied on paraffin embedded tissue. We present the results of analysis for the presence of N- and KRAS mutations, in codons 12, 13, and 61, in snap frozen samples of 100 primary TGCTs, comprising 40 SE and 60 NS. Using the polymerase chain reaction (PCR) and allele specific oligonucleotide hybridization (ASO), mutations were found in five SE (three in NRAS and two in KRAS, all codon 12), and in one NS (KRAS, codon 12). To exclude underestimation of the incidence of RAS mutations in TGCTs due to the presence of an excess of wild type alleles in the analyzed sample, a PCR technique preferentially ampli

Preoperative staging of perforated diverticulitis by computed tomography scanning

Background: Treatment of perforated diverticulitis depends on disease severity classified according to Hinchey's preoperative classification. This study assessed the accuracy of preoperative staging of perforated diverticulitis by computerized tomography (CT) scanning. Methods: All patients who presented with perforated diverticulitis between 1999 and 2009 in two teaching hospitals of Rotterdam, the Netherlands, and in addition had a preoperative CT scan with