43 research outputs found

    Angular gyrus involvement at encoding and retrieval is associated with durable but less specific memories

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    After consolidation, information belonging to a mental schema is better remembered, but such memory can be less specific when it comes to details. A neuronal mechanism in line with this behavioral pattern could result from a dynamic interaction that entails mediation by a specific cortical network with associated hippocampal disengagement. We now report that in male and female adult human subjects, encoding and later consolidation of a series of objects embedded in a semantic schema was associated with a build-up of activity in the angular gyrus (AG) that predicted memory 24h later. In parallel, the posterior hippocampus became less involved as schema objects were successively encoded. Hippocampal disengagement was related to an increase in falsely remembering objects that were not presented at encoding. During both encoding and retrieval, the AG and lateral occipital complex (LOC) became functionally connected and this interaction was beneficial for successful retrieval. Thus, a network including the AG and LOC enhances the overnight retention of schema-related memories, and their simultaneous detachment from the hippocampus reduces the specificity of the memory

    Elucidation of density profile of self-assembled sitosterol plus oryzanol tubules with small-angle neutron scattering

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    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Small-angle neutron scattering (SANS) experiments have been performed on self-assembled tubules of sitosterol and oryzanol in triglyceride oils to investigate details of their structure. Alternative organic phases (deuterated and non-deuterated decane, limonene, castor oil and eugenol) were used to both vary the contrast with respect to the tubules and investigate the influence of solvent chemistry. The tubules were found to be composed of an inner and an outer shell containing the androsterol group of sitosterol or oryzanol and the ferulic acid moieties in the oryzanol molecule, respectively. While the inner shell has previously been detected in SAXS experiments, the outer shell was not discernible due to similar scattering length density with respect to the surrounding solvent for X-rays. By performing contrast variation SANS experiments, both for the solvent and structurant, a far more detailed description of the self-assembled system is obtainable. A model is introduced to fit the SANS data; we find that the dimensions of the inner shell agree quantitatively with the analysis performed in earlier SAXS data (radius of 39.4 ± 5.6 Å for core and inner shell together, wall thickness of 15.1 ± 5.5 Å). However, the newly revealed outer shell was found to be thinner than the inner shell (wall thickness 8.0 ± 6.5 Å). The changes in the scattering patterns may be explained in terms of the contrast between the structurant and the organic phase and does not require any subtle indirect effects caused by the presence of water, other than water promoting the formation of sitosterol monohydrate in emulsions with aqueous phases with high water activity

    Stakeholder-centric assessment of product family architecture : practical guidelines for information system interoperability and extensibility

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    This paper presents a method for software product family teams to assess their family architecture with respect to family-relevant system-qualities. The method extends current architecture assessment practice through its explicit orientation to family-issues; its emphasis on those family-stakeholders neglected by conventional development methods; and its focus on providing practical "how-to" guidelines and mechanisms to enable method-users to successfully complete the required activities. Initial design and implementation of the method addresses the important system-qualities of interoperability and extensibility. The paper has a practical orientation, and concentrates on illustrating research results using industry-based examples from case-studies where the method was applied in the ongoing architecture development of commercial medical information system product families

    Security of Supply in Gas and Hybrid Energy Networks

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    Reliable energy supply becomes increasingly complex in hybrid energy networks, due to increasing amounts of renewable electricity and more dynamic demand. Accurate modeling of integrated electricity and gas distribution networks is required to quantify operational bottlenecks in these networks and to increase security of supply. In this paper, we propose a hybrid network solver to model integrated electricity and gas distribution networks. A stochastic method is proposed to calculate the security of supply throughout the networks, taking into account the likelihood of events, operational constraints and dynamic supply and demand. The stochastic method is evaluated on a real gas network case study. The calculated security of supply parameters provide insight into the most critical parts of the network and can be used for future network planning. The capabilities of the coupled hybrid energy network simulation are demonstrated on the real gas network coupled to a simplified electricity network. Results demonstrate how combined simulation of electricity and gas networks facilitate the control design and performance evaluation of regional hybrid energy networks
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