Manufacturing flow line systems: a review of models and analytical results

The most important models and results of the manufacturing flow line literature are described. These include the major classes of models (asynchronous, synchronous, and continuous); the major features (blocking, processing times, failures and repairs); the major properties (conservation of flow, flow rate-idle time, reversibility, and others); and the relationships among different models. Exact and approximate methods for obtaining quantitative measures of performance are also reviewed. The exact methods are appropriate for small systems. The approximate methods, which are the only means available for large systems, are generally based on decomposition, and make use of the exact methods for small systems. Extensions are briefly discussed. Directions for future research are suggested.National Science Foundation (U.S.) (Grant DDM-8914277

Uniform or Sex-Specific Cardiac Troponin Thresholds to Rule-out Myocardial Infarction at Presentation

Background: Myocardial infarction can be ruled out in patients with a single cardiac troponin measurement. Whether use of a uniform rule-out threshold has resulted in sex-differences in care remains unclear.Objectives: To evaluate implementation of a uniform rule-out threshold in females and males with possible myocardial infarction, and to derive and validate sex-specific thresholds. Methods: The implementation of a uniform rule-out threshold (&lt;5 ng/L) with a high-sensitivity cardiac troponin I assay was evaluated in consecutive patients presenting with possible myocardial infarction. The proportion of low-risk patients discharged from Emergency Department (ED) and incidence of myocardial infarction or cardiac death at 30 days were determined. Sex-specific thresholds were derived and validated, and proportion of female and male patients stratified as low-risk compared with uniform threshold.Results: In 16,792 patients (58±17 years, 46% female) care was guided using a uniform threshold. This identified more female than male patients as low-risk (73% versus 62%), but a similar proportion of low-risk patients were discharged from ED (81% for both) with fewer than 5 (&lt;0.1%) patients having a subsequent myocardial infarction or cardiac death at 30 days. Compared to uniform threshold of &lt;5 ng/L, use of sex-specific thresholds would increase the proportion of female (61.8% versus 65.9%) and reduce the proportion of male (54.8% versus 47.8%) patients identified as low-risk.Conclusions: Implementation of a uniform rule-out threshold for myocardial infarction was safe and effective in both sexes. Sex-specific rule-out thresholds should be considered, but their impact on effectiveness and safety may be limited.Keywords: Cardiac troponin, sex, myocardial infarction<br/

Eustomias eximius Jordan & Gilbert, 1925 (Pisces): arequest for suppression of a neotype following rediscovery of holotype. Z.N. (S.) 1964

Volume: 28Start Page: 164End Page: 16

Feeding Ecology of the Dark-Rumped Petrel in the Galápagos Islands

During a study of Dark-romped Petrel (Pterodroma phaeopygia) breeding biology in the Galapagos Islands, we collected over 80 samples of food regurgitated by petrel chicks. We identified the prey to the lowest possible taxonomic level and determined the relative importance of each food class in the petrel's diet. We also monitored the daily changes in mass of 14 chicks on Floreana Island to determine the quantity of food delivered as well as the food delivery rate. Dark-romped Petrel hatchlings were fed a mixture of stomach oils, semi-digested fish, cephalopods and crustaceans. On the basis of mass composition, about 46% of the diet was cephalopods, about 37% fish, and about 17% crustaceans. Cephalopods, of at least 16 families, occurred with the greatest regularity. Fish were present in the samples more frequently than Crustacea: seven and five families, respectively. Feeding rates were highest in the month after hatching and lowest before fledging. Estimated food loads averaged 68 g and did not increase in size over the growth period. Dark-romped Petrels fed on mainly mesopelagic prey, taken presumably at night, while ranging up to 2,000 km from the colonies, largely southwards