Component redundancy vs system redundancy in the hazard rateordering

Design engineers are well aware of the stochastic result which says that (under the appropriate assumptions) redundancy at the component level is superior to redundancy at the system level. Given the importance of the hazard rate in reliability and life testing, we investigate to what extent this principle holds for the stronger stochastic ordering, viz, hazard rate ordering. Surprisingly, this does not hold for even series systems if the spares do not match the original components in distribution. It is true for series systems however for matching spares, and we conjecture that this is the case in general for k-out-of-n:G systems. We also investigate this principle for cold-standby redundancy (as opposed to active or parallel redundancy)     

Imaging of acute right lower abdominal quadrant pain

This article reviews the clinical diagnosis of appendicitis, indications and options for appendiceal imaging, compares appendiceal CT techniques, and describes the imaging findings with appendicitis and alternative conditions that can clinically mimic appendicitis.     

The Delphi outer detector decision module: Lucifer

Lucifer, a fastbus module functioning as part of the Delphi track trigger hardware in the first- and second-level trigger sequences, is described. This module is designed for flexibility, ease of testing, and usage. These aims are achieved in limited area by extensive use of application-specific IC devices. Hardware implementation, control requirements, and data bus architecture are described     

Does nominal lineup size matter?

The minimum number of distractors required in a lineup varies across jurisdictions. However, available data do not support the importance of nominal lineup size as a criterion of lineup fairness. Two staged-crime experiments were conducted in which the central manipulation was lineup size. In the 1st experiment (N?=?192), lineup structure was varied by adding 0, 3, or 6 poor foils (persons not resembling the suspect) to a relatively good lineup containing the suspect (guilty or innocent) and 3 good foils (persons resembling the suspect). This manipulation did not significantly influence the rates of either correct or false identification. A 2nd experiment (N?=?270) was conducted in which 4, 8, 12, or 16 and 20 people were presented with all good foils. Once again, nominal size was found to have no significant effect on the rates of correct and false identification. The importance of nominal lineup size relative to other aspects of lineup procedure is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Type A behavior pattern and the self-evaluation of abilities: Empirical tests of the self-appraisal model.

The self-appraisal model proposes that Type A behavior reflects active attempts to generate diagnostic information about abilities, particularly in situations that evoke high uncertainty. In Study 1, subjects were provided feedback indicating high or low uncertainty about underlying abilities in two domains. When subjects were more uncertain of their ability in one domain than in the other, Jenkins-Activity-Survey-defined Type As (but not Type Bs) subsequently constructed tests that were biased to assess the more uncertain domain. Study 2 examined postfailure performance. The model holds that Type As perform poorly because they suspend information gathering when faced with evidence that requisite abilities are absent. Results indicated that deficits emerged only if Type As believed that a second task assessed the same abilities as the initial task on which they failed. A final study examined social comparison among Type As and Bs. Results indicated that Type As engaged in social comparison to obtain diagnostic information, primarily when they were uncertain of their ability levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adolescent pregnancy and parenthood: Recent evidence and future directions.

An overview of recent research on adolescent sexual activity, pregnancy, and parenthood is presented, with a focus on the dearth of knowledge concerning psychological precursors and consequences. Although the rate of teenage childbearing has decreased substantially this century, increasing rates of sexual activity, illegitimacy, and welfare receipt raise public concerns. New research is discussed that suggests that many negative outcomes previously ascribed to mothers' age are as much causes or correlates of teenage pregnancy as effects of it, although this claim is less substantiated regarding effects on children of teenage mothers. Literature on fathers and grandmothers is summarized, and suggestions are made for furthering this research. An overview is given of recent successes among intervention programs, and policy implications of the new federal welfare law are considered for teenage mothers and their children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subject Choice and Occupational Aspirations among Pupils at Girls' Schools

Various studies have found that British girls' curriculum subject preferences and future aspirations have changed and diversified in recent years. Other work has suggested that girls educated in single-sex schools might have a different (perhaps less gender-stereotypical) experience of education in comparison with their contemporaries at co-educational schools. This article draws on a study of the preferences of girls in English single-sex schools to explore these issues of subject choice and occupational aspiration further. It is argued that, like girls in mixed-sex secondary schools, single-sex schoolgirls' subject preferences have become more diverse and less gender-stereotypical than was the case twenty years ago. But where single-sex schoolgirls might have been expected to rate maths and science more highly than their counterparts in mixed-sex schools, the reverse was the case. Our findings support the argument that girls are now significantly more academically focused and ambitious for their future occupations than they were twenty years ago. However, we argue that a gender dichotomy remains evident in the types of future occupation chosen by girls.     

Detection of postoperative myocardial ischemia by bedside ST-segment analysis in coronary artery bypass graft patients

INTRODUCTION: Inherited long QT syndrome (LQTS) recently has been associated with mutations in genes coding for potassium (KVLQT1, KCNE1, and HERG) or sodium (SCN5A) ion channels involved in regulating either sodium inward or potassium outward currents of heart cells, resulting in prolongation of the repolarization period. We describe a new mutation, a -1 donor splice site mutation in a kindred with two affected members (QTc = 0.61 and 0.54 sec). METHODS AND RESULTS: Single stranded conformation polymorphism (SSCP) analyses were performed on DNA fragments amplified by polymerase chain reaction from DNA extracted from whole blood. Aberrant conformers were analyzed by DNA sequencing. SSCP analysis of the KVLQT1 gene revealed an aberrant conformer in the affected family members. DNA sequencing confirmed the presence of a G-->A change in the last nucleotide of codon 344. This mutation does not cause an amino acid change, but a change of the splice site characteristics at the 3' end of exon 6. The mutation may affect, through deficient splicing, the putative sixth transmembrane segment of the K+ channel, and this type of mutation has not previously been described in KVLQT1. CONCLUSION: The clinical course of LQTS in the affected family members, in whom no deaths occurred despite 20 to 30 syncopes, can be explained by the ability of the cellular machinery to perform partial correct splicing in the mutant allele. This type of mutation may be misinterpreted as a normal variant, since it is a point mutation causing neither an amino acid change nor the introduction of a stop codon.