26 research outputs found

    The impact of land cover change on a simulated storm event in the Sydney Basin

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    The Regional Atmospheric Modeling System (RAMS) was run at a 1-km grid spacing over the Sydney basin in Australia to assess the impact of land cover change on a simulated storm event. The simulated storm used NCEP-NCAR reanalysis data, first with natural (i.e., pre-European settlement in 1788) land cover and then with satellite-derived land cover representing Sydney's current land use pattern. An intense convective storm develops in the model in close proximity to Sydney's dense urban central business district under current land cover. The storm is absent under natural land cover conditions. A detailed investigation of why the change in land cover generates a storm was performed using factorial analysis, which revealed the storm to be sensitive to the presence of agricultural land in the southwest of the domain. This area interacts with the sea breeze and affects the horizontal divergence and moisture convergence - the triggering mechanisms of the storm. The existence of the storm over the dense urban area of Sydney is therefore coincidental. The results herein support efforts to develop parameterization of urban surfaces in high-resolution simulations of Sydney's meteorological environment but also highlight the need to improve the parameterization of other types of land cover change at the periphery of the urban area, given that these types dominate the explanation of the results. © 2006 American Meteorological Society

    Are Metastases from Metastases Clinical Relevant? Computer Modelling of Cancer Spread in a Case of Hepatocellular Carcinoma

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    Background: Metastasis formation remains an enigmatic process and one of the main questions recently asked is whether metastases are able to generate further metastases. Different models have been proposed to answer this question; however, their clinical significance remains unclear. Therefore a computer model was developed that permits comparison of the different models quantitatively with clinical data and that additionally predicts the outcome of treatment interventions. Methods: The computer model is based on discrete events simulation approach. On the basis of a case from an untreated patient with hepatocellular carcinoma and its multiple metastases in the liver, it was evaluated whether metastases are able to metastasise and in particular if late disseminated tumour cells are still capable to form metastases. Additionally, the resection of the primary tumour was simulated. The simulation results were compared with clinical data. Results: The simulation results reveal that the number of metastases varies significantly between scenarios where metastases metastasise and scenarios where they do not. In contrast, the total tumour mass is nearly unaffected by the two different modes of metastasis formation. Furthermore, the results provide evidence that metastasis formation is an early event and that late disseminated tumour cells are still capable of forming metastases. Simulations also allow estimating how the resection of the primary tumour delays the patient’s death. Conclusion: The simulation results indicate that for this particular case of a hepatocellular carcinoma late metastases, i.e.

    Evaluating Metaphor Reification in Tangible Interfaces

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    International audienceMetaphors are a powerful conceptual device to reason about human actions. As such, they have been heavily used in designing and describing human computer interaction. Since they can address scripted text, verbal expression, imaging, sound, and gestures, they can also be considered in the design and analysis of multimodal interfaces. In this paper we discuss the description and evaluation of the relations between metaphors and their implementation in human computer interaction with a focus on tangible user interfaces (TUIs), a form of multimodal interface. The objective of this paper is to define how metaphors appear in a tangible context in order to support their evaluation. Relying on matching entities and operations between the domain of interaction and the domain of the digital application, we propose a conceptual framework based on three components: a structured representation of the mappings holding between the metaphor source, the metaphor target, the interface and the digital system; a conceptual model for describing metaphorical TUIs; three relevant properties, coherence, coverage and compliance, which define at what extent the implementation of a metaphorical tangible interface matches the metaphor. The conceptual framework is then validated and applied on a tangible prototype in an educational application

    Kansei information processes in early design : design cognition and computation

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    This chapter considers the Kansei information processes involved in the early design process. It emphasizes the necessity of formalizing the earliest phases of design, i. e. the information phase. After a longitudinal research led since 1997, a theoretical model of the information phase of design was proposed. This model was then refined through experiments that we led from various research projects that were developed during the last years thanks to national and European supports. In the framework of the research presented here, the objective was to refine the model especially by considering the cognitive implicit operations which occur in the early generative phases, i. e. between the inspirational phases and the sketching ones. The paper starts with the definition of the following terms: design process, design information, sectors of analogy, kansei information, kansei structures and kansei rules. Kansei information characterizes the whole corpus of information which the designers deal with in the early design process. Especially, from the information phase, the creative process based on metaphors and analogies is decrypted and formalized, with the extraction of generic rules that, after understanding, may be used more systematically in the generative phase of design through future computer aided design tools. Finally we discuss some advances related to cognition and computation of Kansei processes in design.AN

    Intra-abdominal hypertension due to heparin - induced retroperitoneal hematoma in patients with ventricle assist devices: report of four cases and review of the literature

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    <p>Abstract</p> <p>Introduction</p> <p>Elevated intra-abdominal pressure (IAP) has been identified as a cascade of pathophysiologic changes leading in end-organ failure due to decreasing compliance of the abdomen and the development of abdomen compartment syndrome (ACS). Spontaneous retroperitoneal hematoma (SRH) is a rare clinical entity seen almost exclusively in association with anticoagulation states, coagulopathies and hemodialysis; that may cause ACS among patients in the intensive care unit (ICU) and if treated inappropriately represents a high mortality rate.</p> <p>Case Presentation</p> <p>We report four patients (a 36-year-old Caucasian female, a 59-year-old White-Asian male, a 64-year-old Caucasian female and a 61-year-old Caucasian female) that developed an intra-abdominal hypertension due to heparin-induced retroperitoneal hematomas after implantation of ventricular assist devices because of heart failure. Three of the patients presented with dyspnea at rest, fatigue, pleura effusions in chest XR and increased heart rate although b-blocker therapy. A 36-year old female (the forth patient) presented with sudden, severe shortness of breath at rest, 10 days after an "acute bronchitis". At the time of the event in all cases international normalized ratio (INR) was <3.5 and partial thromboplastin time <65 sec. The patients were treated surgically, the large hematomas were evacuated and the systemic manifestations of the syndrome were reversed.</p> <p>Conclusion</p> <p>Identifying patients in the ICU at risk for developing ACS with constant surveillance can lead to prevention. ACS is the natural progression of pressure-induced end-organ changes and develops if IAP is not recognized and treated in a timely manner. Failure to recognize and appropriately treat ACS is fatal while timely intervention - if indicated - is associated with improvements in organ function and patient survival. Means for surgical decision making are based on clinical indicators of adverse physiology, rather than on a single measured parameter.</p

    Strength of Social Tie Predicts Cooperative Investment in a Human Social Network

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    Social networks – diagrams which reflect the social structure of animal groups – are increasingly viewed as useful tools in behavioural ecology and evolutionary biology. Network structure may be especially relevant to the study of cooperation, because the action of mechanisms which affect the cost:benefit ratio of cooperating (e.g. reciprocity, punishment, image scoring) is likely to be mediated by the relative position of actor and recipient in the network. Social proximity could thus affect cooperation in a similar manner to biological relatedness. To test this hypothesis, we recruited members of a real-world social group and used a questionnaire to reveal their network. Participants were asked to endure physical discomfort in order to earn money for themselves and other group members, allowing us to explore relationships between willingness to suffer a cost on another's behalf and the relative social position of donor and recipient. Cost endured was positively correlated with the strength of the social tie between donor and recipient. Further, donors suffered greater costs when a relationship was reciprocated. Interestingly, participants regularly suffered greater discomfort for very close peers than for themselves. Our results provide new insight into the effect of social structure on the direct benefits of cooperation

    The importance of the altricial – precocial spectrum for social complexity in mammals and birds:A review

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    Various types of long-term stable relationships that individuals uphold, including cooperation and competition between group members, define social complexity in vertebrates. Numerous life history, physiological and cognitive traits have been shown to affect, or to be affected by, such social relationships. As such, differences in developmental modes, i.e. the ‘altricial-precocial’ spectrum, may play an important role in understanding the interspecific variation in occurrence of social interactions, but to what extent this is the case is unclear because the role of the developmental mode has not been studied directly in across-species studies of sociality. In other words, although there are studies on the effects of developmental mode on brain size, on the effects of brain size on cognition, and on the effects of cognition on social complexity, there are no studies directly investigating the link between developmental mode and social complexity. This is surprising because developmental differences play a significant role in the evolution of, for example, brain size, which is in turn considered an essential building block with respect to social complexity. Here, we compiled an overview of studies on various aspects of the complexity of social systems in altricial and precocial mammals and birds. Although systematic studies are scarce and do not allow for a quantitative comparison, we show that several forms of social relationships and cognitive abilities occur in species along the entire developmental spectrum. Based on the existing evidence it seems that differences in developmental modes play a minor role in whether or not individuals or species are able to meet the cognitive capabilities and requirements for maintaining complex social relationships. Given the scarcity of comparative studies and potential subtle differences, however, we suggest that future studies should consider developmental differences to determine whether our finding is general or whether some of the vast variation in social complexity across species can be explained by developmental mode. This would allow a more detailed assessment of the relative importance of developmental mode in the evolution of vertebrate social systems
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