423 research outputs found

    Managing design variety, process variety and engineering change: a case study of two capital good firms

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    Many capital good firms deliver products that are not strictly one-off, but instead share a certain degree of similarity with other deliveries. In the delivery of the product, they aim to balance stability and variety in their product design and processes. The issue of engineering change plays an important in how they manage to do so. Our aim is to gain more understanding into how capital good firms manage engineering change, design variety and process variety, and into the role of the product delivery strategies they thereby use. Product delivery strategies are defined as the type of engineering work that is done independent of an order and the specification freedom the customer has in the remaining part of the design. Based on the within-case and cross-case analysis of two capital good firms several mechanisms for managing engineering change, design variety and process variety are distilled. It was found that there exist different ways of (1) managing generic design information, (2) isolating large engineering changes, (3) managing process variety, (4) designing and executing engineering change processes. Together with different product delivery strategies these mechanisms can be placed within an archetypes framework of engineering change management. On one side of the spectrum capital good firms operate according to open product delivery strategies, have some practices in place to investigate design reuse potential, isolate discontinuous engineering changes into the first deliveries of the product, employ ‘probe and learn’ process management principles in order to allow evolving insights to be accurately executed and have informal engineering change processes. On the other side of the spectrum capital good firms operate according to a closed product delivery strategy, focus on prevention of engineering changes based on design standards, need no isolation mechanisms for discontinuous engineering changes, have formal process management practices in place and make use of closed and formal engineering change procedures. The framework should help managers to (1) analyze existing configurations of product delivery strategies, product and process designs and engineering change management and (2) reconfigure any of these elements according to a ‘misfit’ derived from the framework. Since this is one of the few in-depth empirical studies into engineering change management in the capital good sector, our work adds to the understanding on the various ways in which engineering change can be dealt with

    Activation of RhoA and ROCK Are Essential for Detachment of Migrating Leukocytesh

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    Detachment of the rear of the cell from its substratum is an important aspect of locomotion. The signaling routes involved in this adhesive release are largely unknown. One of the few candidate proteins to play a role is RhoA, because activation of RhoA in many cell types leads to contraction, a mechanism probably involved in detachment. To study the role of RhoA in detachment regulation, we analyzed several subsets of expert migratory leukocytes by video microscopy. In contrast to fast-migrating neutrophils, eosinophils do not detach the rear of the cell unless stimulated with serum. When measuring the amount of active RhoA, with the use of a GSTRhotekin pulldown assay, we found that serum is an excellent activator of RhoA in granulocytes. Inhibition of RhoA or one of Rhos target proteins, the kinase ROCK, in neutrophils leads to the phenotype seen in eosinophils: the rear of the cell is firmly attached to the substratum, whereas the cell body is highly motile. ROCK-inhibition leads to impaired migration of granulocytes in filters, on glass, and through endothelial monolayers. Also, the ROCK signaling pathway is involved in changes of integrin-mediated adhesion. Eosinophil transduction by a tat-fusion construct containing active RhoA resulted in detachment stimulation in the presence of chemoattractant. From these results we conclude that activation of the RhoA-ROCK pathway is essential for detachment of migratory leukocytes

    Later zaaien kost opbrengst

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    Onderzoek naar de gevolgen van het uitstellen van het zaaitijdstip op de gewasproductie en op opbrengstderving, bijvoorbeeld doordat de grond later bewerkt kan worden door een hogere grondwaterstand als gevolg van peilverhogin

    Interactive learning objects as a solution to challenges in basic medical science teaching

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    Background. As a core component of any health professions curriculum, basic medical science modules facilitate learning of biology, anatomy, histology and physiology content. To redress the challenges of class size and poor tertiary education readiness, interactive learning objects could facilitate learning and enhance engagement between lecturers and students. Objective. To determine whether the use of learning objects in a basic medical science first-year module is an effective tool for enhancing the student learning experience. Methods. A case study research design with mixed methods of data collection was used. Participants provided informed consent for this study. Learning objects were incorporated into a basic medical sciences first-year module in the Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa. A correlation analysis between usage statistics and assessment results was used to determine the academic effectiveness of this intervention. A thematic network analysis identified the barriers and enablers of the intervention. Results. Student attempts at learning objects correlated with a higher assessment outcome for two of the three tutorials. Technical difficulties, timing and assessment format were barriers to learning with the use of learning objects. Enablers to learning included student enjoyment, facilitating understanding of core concepts, adaptation to new ways of learning and formative assessment. The module team received valuable feedback on the constructed learning environment through the qualitative data collected from students within this study. Conclusion. Interactive learning objects are useful and effective tools for facilitating learning in the context of large, diverse first-year health professions education classes

    Invloed verdichting zandondergrond op snijmaisopbrengst

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    De effecten van verdichting van de ondergronden in zandgronden zijn in een vier jaar durend onderzoek nagegaan
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