The effect of economies-of-scale on the performance of lot-sizing heuristics in rolling horizon basis

In this article, we consider the production planning problem in the presence of (dis)economies-of-scale in production costs on a rolling horizon basis with a fixed forecast horizon. We propose variants of three well-known and commonly used heuristics (Wagner–Whitin, Silver–Meal and Least Unit Cost) adapted for this particular setting. In an extensive numerical study with demands exhibiting stationary, increasing and decreasing trends and seasonality, we demonstrate that having longer forecast horizon is less effective in obtaining more cost effective production plans when the production cost function is convex and also when fixed setup cost is lower, which both are proxy to lack of economies-of-scale

Estimating time-to-onset of adverse drug reactions from spontaneous reporting databases.

International audienceBACKGROUND: Analyzing time-to-onset of adverse drug reactions from treatment exposure contributes to meeting pharmacovigilance objectives, i.e. identification and prevention. Post-marketing data are available from reporting systems. Times-to-onset from such databases are right-truncated because some patients who were exposed to the drug and who will eventually develop the adverse drug reaction may do it after the time of analysis and thus are not included in the data. Acknowledgment of the developments adapted to right-truncated data is not widespread and these methods have never been used in pharmacovigilance. We assess the use of appropriate methods as well as the consequences of not taking right truncation into account (naïve approach) on parametric maximum likelihood estimation of time-to-onset distribution. METHODS: Both approaches, naïve or taking right truncation into account, were compared with a simulation study. We used twelve scenarios for the exponential distribution and twenty-four for the Weibull and log-logistic distributions. These scenarios are defined by a set of parameters: the parameters of the time-to-onset distribution, the probability of this distribution falling within an observable values interval and the sample size. An application to reported lymphoma after anti TNF-¿ treatment from the French pharmacovigilance is presented. RESULTS: The simulation study shows that the bias and the mean squared error might in some instances be unacceptably large when right truncation is not considered while the truncation-based estimator shows always better and often satisfactory performances and the gap may be large. For the real dataset, the estimated expected time-to-onset leads to a minimum difference of 58 weeks between both approaches, which is not negligible. This difference is obtained for the Weibull model, under which the estimated probability of this distribution falling within an observable values interval is not far from 1. CONCLUSIONS: It is necessary to take right truncation into account for estimating time-to-onset of adverse drug reactions from spontaneous reporting databases

Effect of sex steroids on bone formation in an orthopedically expanded suture in rats : An immunohistochemical and computed tomography study.

OBJECTIVE: The purpose of this work was to evaluate the effects of sex steroids on bone formation in response to midpalatal suture expansion by means of histological and immunohistochemical examinations and computed tomography (CT). MATERIALS AND METHODS: A total of 32 male and 32 female 12-week-old Wistar rats were divided into four groups per gender. Testosterone was administered to the castrated experimental male rats, estrogen to castrated experimental female rats. Saline solution was given subcutaneously to the male and female control, sham, and castration groups during expansion and retention periods, which lasted 7 and 5 days, respectively. The expansion amount was measured with a digital caliper. The density of the new bone in the expansion area was measured via CT. RESULTS: Histological and CT evaluation revealed that the number of osteoblasts and density of the new bone was higher in male and female experimental groups than in all the other groups. When scores of staining intensity were compared, the experimental groups demonstrated statistically significant greater immunoreactivity in the osteoblasts compared to castrated-only groups. Bone density was higher in the female experimental group than in the others, and higher in the male experimental group than in the others. Expansion amounts in the castrated groups were higher than in the others (p < 0.05). CONCLUSION: Raising the levels of sex steroids in rats revealed positive effects on bone formation in the midpalatal suture in response to expansion. Increased sex steroid levels can reduce the time needed for retention

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Geoepidemiology and clinical characteristics of neonatal lupus erythematosus: A systematic literature review of individual patients’ data

Background/aim: Neonatal lupus erythematosus (NLE) is an autoimmune syndrome caused by transplacental transmission of maternal autoantibodies, often with devastating consequences. The objective of this systematic literature review was to analyze the demographic data, geoepidemiology, clinical, and serological characteristics associated with NLE. Materials and methods: We performed a systematic literature search of the Pubmed database covering the period from 1976 to August 2015, using the MeSH terms &quot; neonatal lupus” or “congenital heart block”. To be included in the study, articles of any type (original articles, case series, and case reports) had to report on infants with NLE on an individualized (i.e. patient-by-patient) basis. Results: A total of 198 studies were included in the review, reporting on a total of 755 NLE patients. The most frequently reported clinical manifestations of NLE were congenital heart block (CHB, 65.2%), cutaneous lupus (33.1%), and cytopenias (15.5%). We found differences in NLE characteristics based on study geographical origin, with CHB being much more frequent in patients of European or American descent (49.4% and 35%, respectively), while reports originating from Asia reported a higher prevalence of skin involvement (45.2%). Most CHB cases (72.9%) were diagnosed between the 18th and 26th week of gestation. Conclusions: Phenotypic differences of NLE depending on race and country may reflect true pathophysiologic differences or methodologic discrepancies. While maternal autoimmune disease is not a prerequisite for the development of NLE, the existence of a truly &quot; immunonegative” CHB is questionable. © 2020, Turkiye Klinikleri. All rights reserved