An Agent‐Based Model for Pathogen Persistence and Cross‐Contamination Dynamics in a Food Facility

We used an agent‐based modeling (ABM) framework and developed a mathematical model to explain the complex dynamics of microbial persistence and spread within a food facility and to aid risk managers in identifying effective mitigation options. The model explicitly considered personal hygiene practices by food handlers as well as their activities and simulated a spatially explicit dynamic system representing complex interaction patterns among food handlers, facility environment, and foods. To demonstrate the utility of the model in a decision‐making context, we created a hypothetical case study and used it to compare different risk mitigation strategies for reducing contamination and spread of Listeria monocytogenes in a food facility. Model results indicated that areas with no direct contact with foods (e.g., loading dock and restroom) can serve as contamination niches and recontaminate areas that have direct contact with food products. Furthermore, food handlers’ behaviors, including, for example, hygiene and sanitation practices, can impact the persistence of microbial contamination in the facility environment and the spread of contamination to prepared foods. Using this case study, we also demonstrated benefits of an ABM framework for addressing food safety in a complex system in which emergent system‐level responses are predicted using a bottom‐up approach that observes individual agents (e.g., food handlers) and their behaviors. Our model can be applied to a wide variety of pathogens, food commodities, and activity patterns to evaluate efficacy of food‐safety management practices and quantify contamination reductions associated with proposed mitigation strategies in food facilities.     

Substance Use,Distress, and Adolescent School Networks

This study examined the associations of substance use, psychological distress, and mental health services receipt with the structure and content of adolescent school‐based networks. Using data from the National Longitudinal Study of Adolescent Health, we found that substance use was associated with receiving more, but making fewer, peer nominations. It also was associated with less favorable network characteristics, such as low GPA. Services receipt was associated with receiving and making fewer nominations, less favorable network characteristics, and a lower likelihood of reciprocated best friendships. Psychological distress had fewer significant associations. All associations were modest in magnitude. Our results suggest the importance of considering multiple indicators of socioemotional problems and multiple dimensions of social networks in research on adolescent peer relations.     

Technische Softwaredokumentation unter ?konomischen Gesichtspunkten – Ein formal-deduktiver Ansatz

Only a very low priority seems to be given to software documentation. For example, about 80% of the software systems in production worldwide are badly documented. In contrast empirical studies confirm that an adequate technical documentation reduces the error rate of subsequent changes during software maintenance. This leads to the question about the optimal scale of investment in technical documentation in any software project. In research, this decision problem has been largely neglected. Since underlying cause-effect relationships may be empirically hard to detect, this paper proposes a new deductive approach, which compares the present value of payments for the documentation and bug fixing. The basis of this model is the phenomenon of error propagation from one component to adjacent components through its dependencies. As a result the following hypothesis can be inferred: It is always beneficial to document too much rather than comparatively too little even for an arbitrarily low quality of documentation and for any required rate of interest. This hypothesis shows robustness even against some changes in assumptions.     

The effects of state-dependent human behavior on the design of a serial line

Most research on line design assumes that human operators perform independently from the status of the line. Recent empirical evidence is contradictory. Humans are likely to change their working speed if they might otherwise cause idle time (Schultz et al., Manage Sci 44(12):1595–1607, 1998). This peculiarity of worker behavior is observed in a variety of settings but little is still known about optimal line design that accounts for this more realistic modeling of worker behavior. Therefore, we analyze work allocation in a serial line with limited buffer capacity and adaptive human behavior. An extensive simulation study reveals that optimal work allocation in state-dependent models is different from classical state-independent models. A bowl-shaped work allocation might be suboptimal and design guidelines are more complicated. Depending on the extent of human reactions, a bowl-shaped, balanced, or reversed-bowl work allocation can be preferable.     

Open Government: Theoretische Bezüge und konzeptionelle Grundlagen einer neuen Entwicklung in Staat und ?ffentlichen Verwaltungen

New models of innovation have suggested that the innovation process of product and service development is becoming more open, emphasizing the importance of external knowledge and systematically involving external actors and sources in innovation endeavours. The growing success of open innovation practices in many firms raises the question whether these principles can be transferred for reinventing public sector organisations. Beyond technocratic eGovernment and digitalization effort, but with support of web 2.0 technology, we present first examples of how external collaboration and innovation with citizens for public administrations can offer new ways of citizen integration, enhancing public value creation and the political decision making process. In the following, theoretical references and conceptual foundations of this development are identified. By intensive use of internet technologies the aim of Open Government is to achieve more transparency, more participation and a closer collaboration with the various stakeholders in the public sector.