Elektrofunkenerosive Bearbeitbarkeit von vergütbaren Warmarbeitsstählen und ledeburitischen Chromstählen

Entwicklung des Elektrofunkenerodierens. Abtragmechanismus und Kenngrößen beim Senkerodieren. Strukturparameter und Abtragvorgang. Oberflächenbeeinflussung durch den Funkenübergang. Bearbeitung von weichgeglühten und gehärteten Werkzeugstählen. Einflüsse der Oberflächenveränderungen auf die Werkzeugstandzeiten.     

Modeling the effects of hypoglycemia on a two-choice task in adult humans.

Objective: Previous research has demonstrated that hypoglycemia causes reaction times to be slower and more variable. Reaction time tests, however, use multiple cognitive and noncognitive processes. This study is the first to use a validated sequential sampling model (diffusion model) applied to results obtained from a simple 2-choice task in adult humans to assess the effects of hypoglycemia on the basic parameters of decision making. Method: Fourteen adult volunteers were tested on a numerosity discrimination task with and without reduced blood glucose concentrations. The results were analyzed with a model that dissects the components of processing that underlie decisions: the quality of the information on which a decision is based (drift rate), the critical amount of evidence that must be accumulated before a decision is made (boundary separation), and the time taken by nondecision processes. Results: Hypoglycemia resulted in a reduction of mean drift rate from 0.290 to 0.211, t(13) = 4.10, p     

Psychological Contract and Turnover Intention in the Information Technology Profession

The recruitment and retention of Information Technology (IT) professionals continue to concern organizations and researchers. We employ psychological contract theory to examine how unmet expectations may influence psychological contract breach and turnover intention. The results of a survey of IT professionals indicate four factors contributing to IT workers’ perceptions of psychological contract breach including perceived supervisor support, emotional dissonance, work exhaustion, and salary. Further, autonomy moderates the relationship between psychological contract breach and turnover intention.     

Diagnosis of herpetic uveitis and keratouveitis

The use of seven benzoyl-L-amino acids for the detection of carboxypeptidase activities in strains of Gram-negative aerobic and facultatively anaerobic bacteria is reported. A simple overnight assay was designed using ninhydrin for the demonstration of the amino acid released by hydrolysis. Detection of carboxypeptidase activity was shown to have some taxonomic relevance within the Enterobacteriaceae; it was also useful for differentiation within the genus Acinetobacter and for distinction between Pseudomonas aeruginosa and Pseudomonas fluorescens.     

Histone underacetylation is an ancient component of mammalian X chromosome inactivation

Underacetylation of histone H4 is thought to be involved in the molecular mechanism of mammalian X chromosome inactivation, which is an important model system for large-scale genetic control in eukaryotes. However, it has not been established whether histone underacetylation plays a critical role in the multistep inactivation pathway. Here we demonstrate differential histone H4 acetylation between the X chromosomes of a female marsupial, Macropus eugenii. Histone underacetylation is the only molecular aspect of X inactivation known to be shared by marsupial and eutherian mammals. Its strong evolutionary conservation implies that, unlike DNA methylation, histone underacetylation was a feature of dosage compensation in a common mammalian ancestor, and is therefore likely to play a central role in X chromosome inactivation in all mammals.     

Asthma prevalence, morbidity and management practices in South Australia, 1992-1995

BACKGROUND: The Spring South Australian Health Omnibus Survey (SSAHOS) has been used to monitor trends in asthma prevalence, asthma morbidity and asthma management practices between 1992 and 1995. AIMS: To determine if self-reported asthma prevalence and availability of asthma action plans were increasing. To identify deficiencies in asthma management and opportunities for intervention. METHODS: Representative population survey by trained interviewers using a multistage, systematic, clustered area sample of 4200 households in South Australia where people aged 15 years or more are living. RESULTS: Over 3000 interviews were conducted each year. Between 1992 and 1995 the self-reported prevalence of asthma in those aged 15 years or more increased significantly from 15.7% to 20.3% (p < 0.0005), and the prevalence of current asthma increased from 9.3% to 11.4% (p < 0.05). The self-reported availability of individual asthma action plans increased from 21.9% in 1992 to 42.2% in 1995 (p < 0.0005). In 1992, 21% had a nebuliser at home, and 10.5% had a peak flow meter. In 1993, 61.4% were using preventive medications, and 35% thought bronchodilators were 'preventer' medications. In 1994 and 1995, between 12.5% and 15.6% had nocturnal awakening weekly or more often, and 31.4% had morning asthma symptoms weekly or more often. Between 20.1% and 20.8% had lost days from usual activities during the last year. Those on incomes below $20,000 had more symptoms, had more admissions to hospital, and required more medication than those on higher incomes. CONCLUSIONS: Self-reported asthma prevalence has increased. There remains a gap between current asthma management and that recommended by the National Asthma Campaign.     

Dynamic computational geometry on meshes and hypercubes

Parallel algorithms are given for determining geometric properties of systems of moving point-objects. The objects are assumed to be moving in a Euclidean space such that each coordinate of a point's motion is a polynomial of bounded degree in the time variable. The properties investigated include nearest (farthest) neighbor, closest (farthest) pair, collision, convex hull, diameter, and containment. Several of these properties are investigated from both the dynamic and steady-state points of view. Efficient, and often optimal, implementations of these algorithms are given for the mesh and hypercube.Research partially supported by a grant from the Niagara University Research Council.Research partially supported by National Science Foundation grants DCR-8608640 and IRI-8800514.