17 research outputs found

    Vortex formation and instability in the left ventricle

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    We study the formation of the mitral vortex ring during early diastolic filling in a patient-specific left ventricle (LV) using direct numerical simulation. The geometry of the left ventricle is reconstructed from Magnetic Resonance Imaging (MRI) data of a healthy human subject. The left ventricular kinematics is modeled via a cell-based activation methodology, which is inspired by cardiac electro-physiology and yields physiologic LV wall motion. In the fluid dynamics videos, we describe in detail the three-dimensional structure of the mitral vortex ring, which is formed during early diastolic filling. The ring starts to deform as it propagates toward the apex of the heart and becomes inclined. The trailing secondary vortex tubes are formed as the result of interaction between the vortex ring and the LV wall. These vortex tubes wrap around the circumference and begin to interact with and destabilize the mitral vortex ring. At the end of diastole, the vortex ring impinges on the LV wall and the large-scale intraventricular flow rotates in clockwise direction. We show for the first time that the mitral vortex ring evolution is dominated by a number of vortex-vortex and vortex-wall interactions, including lateral straining and deformation of vortex ring, the interaction of two vortex tubes with unequal strengths, helicity polarization of vortex tubes and twisting instabilities of the vortex cores

    The East Asian Journal of British History, vol. 3

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    The East Asian Journal of British History is produced by the East Asian Society of British History, and supported by the Institute for Historical Research. The Institute of Historical Research is pleased and proud to be supporting this recent addition to British history scholarship. Developing out of the IHR’s long-standing collaborative partnership with Japanese universities, and now in its fourth year, the East Asian Journal of British History features some of the best emergent scholarship from Anglophone historians working in China, Japan, and South Korea. Divided between an articles section and one devoted to reviews, the journal’s remit wide-ranging covering all fields and periods of British history. It complements the triennial Anglo-Japanese Conference organised by the IHR and Japanese historians based at the universities of Tokyo, Kyoto and Osaka, and the conference of the East Asian Society of British history, in which we are joined by our colleagues from South Korea. In future, we hope that more contributions will be featured in the journal from the Chinese mainland and from Taiwan

    Corporate philanthropy through the lens of ethical subjectivity

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    The dynamic organisational processes in businesses dilute the boundaries between the individual, organisational, and societal drivers of corporate philanthropy. This creates a complex framework in which charitable project selection occurs. Using the example of European tour operators, this study investigates the mechanisms through which companies invest in charitable projects in overseas destinations. Inextricably linked to this is the increasing contestation by local communities as to how they are able to engage effectively with tourism in order to realise the benefits tourism development can bring. This research furthers such debates by exploring the processes through which tour operators facilitate community development through charitable giving. Findings show, with no formal frameworks in existence, project selection depends upon emergent strategies that connect the professional with the personal, with trust being positioned as a central driver of these informal processes. Discretionary responsibilities are reworked through business leaders’ commitment to responsible business practises and the ethical subjectivity guiding these processes

    BioWIM: A MultiSurface, MultiTouch Interface for Exploratory Visualization of Biomedical Data

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    This paper presents the BioWIM, a multi-surface, multi-touch interface for exploring visualizations of complex biomedical environments using a semi-immersive virtual reality (VR) display. The BioWIM reinterprets the traditional world-in-miniature (WIM) VR metaphor within the context of navigating visualizations based on medical imaging data and using the unique capabilities provided by coupling a multi-touch table with a stereoscopic display wall. A "Window to the World" metaphor is used to navigate a detailed 3D scene displayed on the vertical surface by manipulating widgets and making touch gestures on top of medical imaging data displayed on the table. The technique supports navigation through complex environments while maintaining context. The results of a controlled user study comparing the BioWIM to a more traditional touch interface demonstrate improvements in accuracy in a compound search and size judgment task when using the BioWIM. An interpretation of these results and discussion of design principles and lessons learned is presented
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