Two decades of research in L2 peer review

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Replenishment prioritization of highly perishable goods : a case study on nuclear medicine

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2007.Cataloged from PDF version of thesis.Includes bibliographical references (p. 74).Serving customers in a nuclear medicine supply chain requires frequent and responsive replenishments. Nuclear medicine is a special category of perishable goods that is subject to rapid, but predictable radioactive decay. This study examines the viability of differentiating service through segmenting customers in Tyco Healthcare's (THC's) nuclear medicine supply chain. More specifically, the network of pharmacies that THC serves is divided into two groups-THC-affiliate pharmacies and independent pharmacies-and their demand characteristics are examined. This study rejects the hypothesis that THC should differentiate service by pharmacy affiliation after comparing the demand characteristics of the THC and independent pharmacies. Alternatively, the study tests the hypothesis that product segmentation is a viable option by comparing the demand characteristics of THC's products. This study does not reject the alternative hypothesis and presents proposed policy for coordinated replenishment. To facilitate the comparative analyses, THC's nuclear medicine supply chain is first described. Finally, recommendations on how to improve supply chain performance follow the hypothesis testing.by Young-bai Michael Yea and Hui Zou.M.Eng.in Logistic

Generalized confidence intervals for the ratio or difference of two means for lognormal populations with zeros

We discuss in this article methods for analyzing lognormal data that may include zeros. Specifically, we are interested in interval estimation for the ratio or difference of the population means. We propose here two generalized pivotal (GP) approaches: a ``true\u27\u27 GP method and an ``approximate\u27\u27 GP method. Additionally, we propose two likelihood-based approaches: a signed log-likelihood ratio (SLLR) method and a modified SLLR method. Our simulation studies suggest that the approximate generalized pivotal approach outperforms all other known methods; it results in highly accurate coverage frequencies and fairly low bias, even in small sample settings

Interval Estimation for the Ratio and Difference of Two Lognormal Means

Health research often gives rise to data that follow lognormal distributions. In two sample situations, researchers are likely to be interested in estimating the difference or ratio of the population means. Several methods have been proposed for providing confidence intervals for these parameters. However, it is not clear which techniques are most appropriate, or how their performance might vary. Additionally, methods for the difference of means have not been adequately explored. We discuss in the present article five methods of analysis. These include two methods based on the log-likelihood ratio statistic and a generalized pivotal approach. Additionally, we provide and discuss the results of a series of computer simulations. Finally, the techniques are applied to a real example

Functional recovery of older people with hip fracture: does malnutrition make a difference?

Aim To report a study of the effects of protein‐energy malnutrition on the functional recovery of older people with hip fracture who participated in an interdisciplinary intervention. Background It is not clear whether protein‐energy malnutrition is associated with worse functional outcomes or it affects the interdisciplinary intervention program on the functional recovery of older people with hip fracture. Design A randomized experimental design. Methods Data were collected between 2002–2006 from older people with hip fracture ( N  = 162) in Taiwan. The generalized estimating equations approach was used to evaluate the effect of malnutrition on the functional recovery of older people with hip fracture. Results The majority of older patients with hip fracture were malnourished (48/80, 60% in the experimental group vs. 55/82, 67% in the control group) prior to hospital discharge. The results of the generalized estimating equations analysis demonstrated that subjects suffering from protein‐energy malnutrition prior to hospital discharge appeared to have significantly worse performance trajectories for their activities of daily living, instrumental activities of daily living, and recovery of walking ability compared with those without protein‐energy malnutrition. In addition, it was found that the intervention is more effective on the performance of activities of daily living and recovery of walking ability in malnourished patients than in non‐malnourished patients. Conclusion Healthcare providers should develop a nutritional assessment/management system in their interdisciplinary intervention program to improve the functional recovery of older people with hip fracture.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99041/1/jan12027.pd