289 research outputs found

    A System Dynamics based Perspective to Help to Understand the Managerial Big Picture in Respect of Urban Event Dynamics

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    AbstractIn the PED-community, a lot of conducted work focuses on a detailed aspect of the big picture in respect of pedestrian dynamics and disaster avoidance. Surprisingly, the field of research does not offer a lot of models including a managerial macro perspective to explain – for example – why there are mass gatherings that result in high density pedestrian conditions. To improve the mental models of researchers, managers and policy makers, this paper tries to tackle this research gap, by using the methodology of System Dynamics to explain with causal loop diagrams occurring dynamics of urban events to avoid critical situations beforehand

    A Series of 15 Patients with Extracranial Carotid Artery Aneurysms: Surgical and Endovascular Treatment

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    AbstractObjectivesThis is a retrospective review of 15 patients with primary and secondary aneurysms of extracranial carotid arteries treated surgically and endoluminally over 20 years in one centre.Patients and methodsFifteen aneurysms of extracranial carotid arteries were noticed in the same number of patients: five atherosclerotic, two after previous carotid surgery, six post-traumatic, one inflammatory, one of unknown etiology. All of them were symptomatic.ResultsIn the group treated surgically some complications occurred in the perioperative time: one haematoma, two transient neurological deficits, one fatal stroke. In the endovascular group of patients no complications occurred after the treatment. One fatal stroke occurred during operation—the patient died on the 43rd postoperative day due to respiratory insufficiency. Two other deaths occurred during the follow-up: one caused by myocardial infarction 10 years after the aneurysm resection, and the second due to a fatal stroke 3 years after aneurysmorraphy. One patient refused treatment and died 9 months after being diagnosed.ConclusionNeurological deficits in patients after neck injuries should arouse the suspicion of the presence of a carotid artery aneurysm. Open repair remains the method of choice in treating carotid artery aneurysms but endovascular procedures create the possibility of treating extracranial aneurysms in selected cases when open surgery is not recommended

    Liver imaging reporting and data system: An expert consensus statement

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    The increasing incidence and high morbidity and mortality of hepatocellular carcinoma (HCC) have inspired the creation of the Liver Imaging Reporting and Data System (LI-RADS). LI-RADS aims to reduce variability in exam interpretation, improve communication, facilitate clinical therapeutic decisions, reduce omission of pertinent information, and facilitate the monitoring of outcomes. LI-RADS is a dynamic process, which is updated frequently. In this article, we describe the LI-RADS 2014 version (v2014), which marks the second update since the initial version in 2011

    Evaluation of Mixing Efficiency and How it Affects the Properties of the New Green Sand Mixtures

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    The current trend in the preparation of green sand mixtures emphasizes the acceleration of the mixing process while maintaining the quality of the mixture. This requirement results in the necessity of determining the optimal conditions for mixing the mixture with a given mixer. This work aims to determine the optimal mixing conditions for the newly introduced eddy mixer LM-3e from the company Multiserw-Morek in the sand laboratory at the Department of Metallurgical Technologies, Faculty of Materials and Technology, VŠB - Technical University of Ostrava. The main monitored properties of mixtures will be green compressive strength and moisture of the mixture. The measured properties of the mixture mixed on the eddy mixer will be compared with the properties of the mixture mixed on the existing LM-2e wheel mixer. The result of the experiment confirmed that the eddy mixer is suitable for the preparation of a mixture of the same quality as the wheel mixer but with a significantly reduced mixing time

    Oppilatio+ - A data and cognitive science based approach to analyze pedestrian flows in networks

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    Public transport services are a widespread and environmentally friendly option for mobility. In the majority of cases, passengers of public transport services will have to walk from a subway, train, or bus station to their desired travel destination. In an urban environment with a network of narrow streets, this can lead to crowd congestions during rush hour, due to the fact that passengers tend to arrive in waves. In order to monitor and analyze such crowding behavior, city planners, crowd managers, and organizers of public events must ascertain which routes these pedestrians will take from the respective station to their destination. The Oppilatio+ approach is suitable for solving this problem. It is an easy-to-apply approach to predict way-finding behavior with a minimal set of information. The necessary data includes the schedule of incoming transport vehicles at the stations and the time-stamped count of pedestrians at the respective destinations. Under these conditions, the Oppilatio+ approach is suitable for estimating the distribution of pedestrians on all possible walkways between stations and destinations. This information helps crowd control experts to recognize weak spots in the infrastructure and help event organizers to ensure an undisturbed arrival at their event. We validated our approach using two field experiments. The first one was a field study on a public event, and the second one was a case study for a large Swiss train station

    Characterization of the HeCo mutant mouse: a new model of subcortical band heterotopia associated with seizures and behavioral deficits.

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    In human, neuronal migration disorders are commonly associated with developmental delay, mental retardation, and epilepsy. We describe here a new mouse mutant that develops a heterotopic cortex (HeCo) lying in the dorsolateral hemispheric region, between the homotopic cortex (HoCo) and subcortical white matter. Cross-breeding demonstrated an autosomal recessive transmission. Birthdating studies and immunochemistry for layer-specific markers revealed that HeCo formation was due to a transit problem in the intermediate zone affecting both radially and tangentially migrating neurons. The scaffold of radial glial fibers, as well as the expression of doublecortin is not altered in the mutant. Neurons within the HeCo are generated at a late embryonic age (E18) and the superficial layers of the HoCo have a correspondingly lower cell density and layer thickness. Parvalbumin immunohistochemistry showed the presence of gamma-aminobutyric acidergic cells in the HeCo and the mutant mice have a lowered threshold for the induction of epileptic seizures. The mutant showed a developmental delay but, in contrast, memory function was relatively spared. Therefore, this unique mouse model resembles subcortical band heterotopia observed in human. This model represents a new and rare tool to better understand cortical development and to investigate future therapeutic strategies for refractory epilepsy
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