Ulna impaction syndrome therapy: decompressive surgical procedures of the head of the ulna]

The ulnar impaction syndrome can be defined as the impaction of the ulnar head against the triangular fibrocartilage complex and ulnar carpus. As a result of this pattern, painful degeneration of the TFCC occurs. Wrist arthroscopy offers a certain diagnostic tool. In addition, arthroscopic debridement of the TFCC shows a high success rate of 70 to 80 percent. After failed arthroscopic debridement, ulnar shortening osteotomy reduces ulnar load significantly. Malunion of the radius resulting in posttraumatic ulna-plus variance should be treated by correction osteotomy with lengthening of the radius. If arthrosis of the distal radioulnar joint is combined with ulnar impaction syndrome, the hemiresection procedure of Bowers or the method of Kapandji-Sauvé are the methods of choice.     

Design schemes for the X̄ control chart

This paper studies several issues regarding the design of the X? control chart under normality. Different estimators of the standard deviation are considered and the effect of the estimator on the performance of the control chart is investigated. Furthermore, the choice of the factor used to get accurate control limits for moderate sample sizes is addressed. The paper gives an overview on the performance of the charts by studying different characteristics of the run length distribution, both in the in‐control and in the out‐of‐control situation. Copyright © 2008 John Wiley & Sons, Ltd.     

Development of Sitophilus zeamais Motschulsky,in maize kernels and pellets made from maize kernel fractions

As a means of studying certain aspects of resistance of maize varieties to Sitophilus zeamais, various types of pellets were prepared using ground maize and compared with whole, pericarpless, and germless kernels. Numbers of weevil progeny (from six females and three males, and usually a 7-day oviposition period) were greatest in pellets made of flour moistened with water containing agar. More progeny was produced in pellets than in whole kernels. Damaged kernels (hot-water treated, pericarpless, germless) were more susceptible than undamaged kernels and fewer weevil progeny were produced in pellets made of germless kernels than from pellets of whole kernels. Additions of small amounts of extra germ tissue to whole maize flour enhanced the susceptibility of pellets to the weevil, but adding larger amounts of germ of pericarp reduced progeny number, weight and developmental speed.     

On the Use of the Expected ARL Metric for Control Charts Based on Estimated Parameters

At the origination of the Shewhart control chart, it was assumed that the process parameters were known. The in‐control Average Run Length (ARL) and the probability of having a false alarm (P) were introduced as metrics to indicate the in‐control performance. These two metrics are related when the process data are i.i.d. normally distributed: the ARL equals 1/P. When the process parameters are unknown and have to be estimated, a similar relation holds for each estimated control chart, but the relation between the expected ARL (the average of the ARLs of all possible estimated charts) and the expectedP is different. Control charts based on estimates are often designed such that the in‐control ARL equals a predefined value. This paper shows that the expected in‐control ARL is a less suitable design criterion. Copyright © 2016 John Wiley & Sons, Ltd.     

The performance of control charts for large non‐normally distributed datasets

Because of digitalization, many organizations possess large datasets. Furthermore, measurement data are often not normally distributed. However, when samples are sufficiently large, the central limit theorem may be used for the sample means. In this article, we evaluate the use of the central limit theorem for various distributions and sample sizes, as well as its effects on the performance of a Shewhart control chart for these large non‐normally distributed datasets. To this end, we use the sample means as individual observations and a Shewhart control chart for individual observations to monitor processes. We study the unconditional performance, expressed as the expectation of the in‐control average run length (ARL), as well as the conditional performance, expressed as the probability that the control chart based on estimated parameters will have a lower in‐control ARL than a specified desired in‐control ARL. We use recently developed factors to correct the control limits to obtain a specified conditional or unconditional in‐control performance. The results in this paper indicate that the control chart should be applied with caution, even with large sample sizes.