Software Programs To Increase The Utility Of Predictive Microbiology Information*

Author(s):  
Mark Tamplin ◽  
J√≥zsef Baranyi ◽  
Greg Paoli
2020 ◽  
Vol 15 (6) ◽  
pp. 1900343 ◽  
Author(s):  
Woo Dae Jang ◽  
Sang Mi Lee ◽  
Hyun Uk Kim ◽  
Sang Yup Lee

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Julia Mang ◽  
Helmut Küchenhoff ◽  
Sabine Meinck ◽  
Manfred Prenzel

Abstract Background Standard methods for analysing data from large-scale assessments (LSA) cannot merely be adopted if hierarchical (or multilevel) regression modelling should be applied. Currently various approaches exist; they all follow generally a design-based model of estimation using the pseudo maximum likelihood method and adjusted weights for the corresponding hierarchies. Specifically, several different approaches to using and scaling sampling weights in hierarchical models are promoted, yet no study has compared them to provide evidence of which method performs best and therefore should be preferred. Furthermore, different software programs implement different estimation algorithms, leading to different results. Objective and method In this study, we determine based on a simulation, the estimation procedure showing the smallest distortion to the actual population features. We consider different estimation, optimization and acceleration methods, and different approaches on using sampling weights. Three scenarios have been simulated using the statistical program R. The analyses have been performed with two software packages for hierarchical modelling of LSA data, namely Mplus and SAS. Results and conclusions The simulation results revealed three weighting approaches performing best in retrieving the true population parameters. One of them implies using only level two weights (here: final school weights) and is because of its simple implementation the most favourable one. This finding should provide a clear recommendation to researchers for using weights in multilevel modelling (MLM) when analysing LSA data, or data with a similar structure. Further, we found only little differences in the performance and default settings of the software programs used, with the software package Mplus providing slightly more precise estimates. Different algorithm starting settings or different accelerating methods for optimization could cause these distinctions. However, it should be emphasized that with the recommended weighting approach, both software packages perform equally well. Finally, two scaling techniques for student weights have been investigated. They provide both nearly identical results. We use data from the Programme for International Student Assessment (PISA) 2015 to illustrate the practical importance and relevance of weighting in analysing large-scale assessment data with hierarchical models.


1993 ◽  
Vol 19 (3) ◽  
pp. 637-660 ◽  
Author(s):  
Richard A. Wolfe ◽  
Robert P. Gephart ◽  
Thomas E. Johnson

The development of software programs designed to facilitate qualitative data analysis has proltferated recently. Despite their potential to contribute much to management research, very little concerning the use of such programs has appeared in the management literature. The purpose of this paper is to review the current state of computer-facilitated qualitative data analysis [CQDA] in order to contribute to its effective use by management researchers. In an effort to achieve this purpose we discuss why CQDA programs are proliferating, describe the potential of such programs to contribute to management research, address program capabilities and features, describe CQDA applications in management research, and review issues researchers should be aware of in considering the use of C&DA.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 355
Author(s):  
Arícia Possas ◽  
Olga María Bonilla-Luque ◽  
Antonio Valero

Cheeses are traditional products widely consumed throughout the world that have been frequently implicated in foodborne outbreaks. Predictive microbiology models are relevant tools to estimate microbial behavior in these products. The objective of this study was to conduct a review on the available modeling approaches developed in cheeses, and to identify the main microbial targets of concern and the factors affecting microbial behavior in these products. Listeria monocytogenes has been identified as the main hazard evaluated in modelling studies. The pH, aw, lactic acid concentration and temperature have been the main factors contemplated as independent variables in models. Other aspects such as the use of raw or pasteurized milk, starter cultures, and factors inherent to the contaminating pathogen have also been evaluated. In general, depending on the production process, storage conditions, and physicochemical characteristics, microorganisms can grow or die-off in cheeses. The classical two-step modeling has been the most common approach performed to develop predictive models. Other modeling approaches, including microbial interaction, growth boundary, response surface methodology, and neural networks, have also been performed. Validated models have been integrated into user-friendly software tools to be used to obtain estimates of microbial behavior in a quick and easy manner. Future studies should investigate the fate of other target bacterial pathogens, such as spore-forming bacteria, and the dynamic character of the production process of cheeses, among other aspects. The information compiled in this study helps to deepen the knowledge on the predictive microbiology field in the context of cheese production and storage.


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