The value of rescheduling functionality within standard MRP packages

One of the basic functions of an MRP system is to issue rescheduling messages that urge the planner tospeed up or slow down open orders. It seems in practice that these messages are not used at all by planners. This is mostly due to the inaccuracy of MRP, that more or less ignores safety time, safety stocks and lotsize flexibility in the calculation of reschedule-in messages. Reschedule-out messages are usually ignored because planners do not see the value of the message. Other reasons for not adhering to rescheduling messages are a lack of maintenance of MRP parameters or simply the wrong use of the MRP function. In the future, MRP rescheduling functionality will be used even less than today, due to the changing role of MRP within the planning framework. With the uprise of finite capacity scheduling packages, MRP is being pushed one level upward in the planning hierarchy. This means that rescheduling functionalities for the short term will become completely obsolete in MRP systems.     

Allometric Scaling: Analysis of LD50 Data

The need to identify toxicologically equivalent doses across different species is a major issue in toxicology and risk assessment. In this article, we investigate interspecies scaling based on the allometric equation applied to the single, oral LD ₅₀ data previously analyzed by Rhomberg and Wolff.⁽ 1 ⁾ We focus on the statistical approach, namely, regression analysis of the mentioned data. In contrast to Rhomberg and Wolff's analysis of species pairs, we perform an overall analysis based on the whole data set. From our study it follows that if one assumes one single scaling rule for all species and substances in the data set, then β= 1 is the most natural choice among a set of candidates known in the literature. In fact, we obtain quite narrow confidence intervals for this parameter. However, the estimate of the variance in the model is relatively high, resulting in rather wide prediction intervals.     

A Model for Setting Performance Objectives for Salmonella in the Broiler Supply Chain

A stochastic model for setting performance objectives for Salmonella in the broiler supply chain was developed. The goal of this study was to develop a model by which performance objectives for Salmonella prevalence at various points in the production chain can be determined, based on a preset final performance objective at the end of the processing line. The transmission of Salmonella through the broiler production chain was modeled. The prevalence at flock level was calculated from the measured prevalence at sample level. The transmission model is based on data on the occurrence of Salmonella collected in the Dutch broiler production chain during several years. The developed model can be used by policymakers and industry to determine economically and politically acceptable performance objectives for various points of the production chain and to draw conclusions about which interventions are most appropriate.     

Comment se font les administrations : analyser des activités administratives constituantes

Between studies in historical sociology on changes in public administrations and microsociological analyses of the ordinary work done by civil servants, an intermediate perspective is advocated, one centered on “constituent administrative activities”. Following a panorama of the varied researches on public administrations, the proposal is made to focus on the arrangements that shape administrations and form their essential operations. Recruitment, personnel evaluation, the division of labor, the restructuring of hierarchies and the activities of keeping written records and statistics (writing and counting) should be the subjects of study. When placed in their historical and social contexts, they help us better understand how public administrations last and change. Discussing the scale of analysis and making comparisons over time and in space, this article presents the other contributions to this special issue. Less linear approaches are suggested for analyzing the historical processes of the “bureaucratization” and “managerialization” of administrative systems.     

SexEd.com: Values and norms in web‐based sexuality education

The sexual values and norms transmitted to adolescents through school‐based sexuality education programs have been noted and critiqued by an interdisciplinary pool of researchers. With the increasing availability of the Internet to many American adolescents, the opportunities it provides for discreet and independent exploration, and the virtual lack of regulation of information provided by web sites, the Internet is emerging as a unique and critical site of sexuality education. This work analyzes the values and norms transmitted to adolescents via 52 sexuality education web sites, drawing parallels to its school‐based counterpart and interrogating the reliance of all forms of sexuality education on a problem‐focused, gendered, and narrowly‐bounded discourse of adolescent sexuality.     

Ridge regression: A multivariate analysis of criminal activity

The objective of the paper is to apply the statistical procedure of ridge regression to a multivariate model of criminal activity. The explanatory variables are of an economic, apprehension, and seasonal nature. The Time Shared Reactive On Line Laboratory (TROLL) computer package was used in estimating all regression coefficients and other pertinent statistics. The economic variables, which included per capita personal income, hours worked, and plant closing dummy variable, were found to be statistically related to criminal activity. In addition, police expenditures as well as the three seasonal dummy variables were statistically associated with the dependent variable. A comparison is made between the results obtained from the ordinary least squares procedure and the ridge regression approach.