1,750 research outputs found

    Prognostic Value of Coronary CT Angiography

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    Ongoing large randomized clinical trials on complex percutaneous coronary interventions:Intravascular imaging-guided trials

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    .tabletop{ vertical-align: top; } ABSTRACT Percutaneous coronary intervention of complex coronary artery disease remains challenging and is still associated with suboptimal cardiovascular outcomes. Over the years, different strategies and technologies have been developed to improve these results. Particularly, the development and evolution of intravascular imaging modalities to guide the procedure have improved lesion assessment and preparation, and stent optimization. However, whether these advantages are beneficial in this particular setting is still under discussion. In this article we intend to briefly summarize previous imaging-guided trials and give an outline on the ongoing large trials that are being conducted on imaging-guided interventions in complex coronary disease

    Amphioxus makes the cut Again

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    The cephalochordate amphioxus is now established as an important model system for understanding the evolution of vertebrate novelties from an invertebrate chordate ancestor. It is also emerging as a serious candidate for studies of organ regeneration. We extend here our previous observations on the European amphioxus´ extensive adult regenerative capacity. The expression of Wnt5 and the presence of β-catenin protein in the early bud-stage blastema support a role for Wnt signaling during tail regeneration in amphioxus. We also present data showing that Branchiostoma lanceolatum continues to regenerate well after repeated amputation of the post-anal tail. These results are discussed in relation to vertebrate regeneration and other stem cell systems, and in the context of regeneration decline with aging

    Virtual VMASC: A 3D Game Environment

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    The advantages of creating interactive 3D simulations that allow viewing, exploring, and interacting with land improvements, such as buildings, in digital form are manifold and range from allowing individuals from anywhere in the world to explore those virtual land improvements online, to training military personnel in dealing with war-time environments, and to making those land improvements available in virtual worlds such as Second Life. While we haven't fully explored the true potential of such simulations, we have identified a requirement within our organization to use simulations like those to replace our front-desk personnel and allow visitors to query, naVigate, and communicate virtually with various entities within the building. We implemented the Virtual VMASC 3D simulation of the Virginia Modeling Analysis and Simulation Center (VMASC) office building to not only meet our front-desk requirement but also to evaluate the effort required in designing such a simulation and, thereby, leverage the experience we gained in future projects of this kind. This paper describes the goals we set for our implementation, the software approach taken, the modeling contribution made, and the technologies used such as XNA Game Studio, .NET framework, Autodesk software packages, and, finally, the applicability of our implementation on a variety of architectures including Xbox 360 and PC. This paper also summarizes the result of our evaluation and the lessons learned from our effort

    Geodesic vulnerability approach for identification of critical buses in power systems

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    One of the most critical issues in the evaluation of power systems is the identification of critical buses. For this purpose, this paper proposes a new methodology that evaluates the substitution of the power flow technique by the geodesic vulnerability index to identify critical nodes in power grids. Both methods are applied comparatively to demonstrate the scope of the proposed approach. The applicability of the methodology is illustrated using the IEEE 118-bus test system as a case study. To identify the critical components, a node is initially disconnected, and the performance of the resulting topology is evaluated in the face of simulations for multiple cascading faults. Cascading events are simulated by randomly removing assets on a system that continually changes its structure with the elimination of each component. Thus, the classification of the critical nodes is determined by evaluating the resulting performance of 118 different topologies and calculating the damage area for each of the disintegration curves of cascading failures. In summary, the feasibility and suitability of complex network theory are justified to identify critical nodes in power systems

    JNK mediates differentiation, cell polarity and apoptosis during amphioxus development by regulating actin cytoskeleton dynamics and ERK signalling

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    c-Jun terminal kinase (JNK) is a multi-functional protein involved in a diverse array of context-dependent processes, including apoptosis, cell cycle regulation, adhesion and differentiation. It is integral to a number of signalling cascades, notably downstream of non-canonical Wnt and MAPK signalling pathways. As such, it is a key regulator of cellular behaviour and patterning during embryonic development across the animal kingdom. The cephalochordate amphioxus is an invertebrate chordate model system straddling the invertebrate to vertebrate transition and is thus ideally suited for comparative studies of morphogenesis. However, next to nothing is known about JNK signalling or cellular processes in this lineage. Pharmacological inhibition of JNK signalling using SP600125 during embryonic development arrests gastrula invagination and causes convergence extension-like defects in axial elongation, particularly of the notochord. Pharynx formation and anterior oral mesoderm derivatives like the preoral pit are also affected. This is accompanied by tissue-specific transcriptional changes, including reduced expression of six3/6 and wnt2 in the notochord, and ectopic wnt11 in neurulating embryos treated at late gastrula stages. Cellular delamination results in accumulation of cells in the gut cavity and a dorsal fin-like protrusion, followed by secondary Caspase3-mediated apoptosis of polarity-deficient cells, a phenotype only partly rescued by co-culture with the pan-caspase inhibitor Z-VAD-fmk. Ectopic activation of ERK signalling in the neighbours of extruded notochord and neural cells, possibly due to altered adhesive and tensile properties

    System Dynamics Modeling for Supporting Drought-Oriented Management of the Jucar River System, Spain

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    [EN] The management of water in systems where the balance between resources and demands is already precarious can pose a challenge and it can be easily disrupted by drought episodes. Anticipated drought management has proved to be one of the main strategies to reduce their impact. Drought economic, environmental, and social impacts affect different sectors that are often interconnected. There is a need for water management models able to acknowledge the complex interactions between multiple sectors, activities, and variables to study the response of water resource systems to drought management strategies. System dynamics (SD) is a modeling methodology that facilitates the analysis of interactions and feedbacks within and between sectors. Although SD has been applied for water resource management, there is a lack of SD models able to regulate complex water resource systems on a monthly time scale and considering multiple reservoir operating rules, demands, and policies. In this paper, we present an SD model for the strategic planning of drought management in the Jucar River system, incorporating dynamic reservoir operating rules, policies, and drought management strategies triggered by a system state index. The DSS combines features from early warning and information systems, allowing for the simulation of drought strategies, evaluating their economic impact, and exploring new management options in the same environment. The results for the historical period show that drought early management can be beneficial for the performance of the system, monitoring the current state of the system, and activating drought management measures results in a substantial reduction of the economic impact of droughts.The data used in this study was obtained from the references included. We acknowledge the European Research Area for Climate Services consortium (ER4CS) and the Agencia Estatal de Investigacion for their financial support to this research under the INNOVA project (Grant Agreement: 690462; PCIN-2017-066). This study has also been partially funded by the ADAPTAMED project (RTI2018-101483-B-I00) from the Ministerio de Ciencia, Innovacion y Universidades (MICIU) of Spain.Rubio-Martin, A.; Pulido-Velazquez, M.; Macian-Sorribes, H.; Garcia-Prats, A. (2020). System Dynamics Modeling for Supporting Drought-Oriented Management of the Jucar River System, Spain. Water. 12(5):1-19. https://doi.org/10.3390/w12051407S119125Mishra, A. K., & Singh, V. P. (2010). A review of drought concepts. Journal of Hydrology, 391(1-2), 202-216. doi:10.1016/j.jhydrol.2010.07.012Momblanch, A., Paredes-Arquiola, J., Munné, A., Manzano, A., Arnau, J., & Andreu, J. (2015). Managing water quality under drought conditions in the Llobregat River Basin. 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Drought Management Plans in the European Union. The Case of Spain. Water Resources Management, 26(6), 1537-1553. doi:10.1007/s11269-011-9971-2Pedro-Monzonís, M., Solera, A., Ferrer, J., Estrela, T., & Paredes-Arquiola, J. (2015). A review of water scarcity and drought indexes in water resources planning and management. Journal of Hydrology, 527, 482-493. doi:10.1016/j.jhydrol.2015.05.003Zaniolo, M., Giuliani, M., Castelletti, A. F., & Pulido-Velazquez, M. (2018). Automatic design of basin-specific drought indexes for highly regulated water systems. Hydrology and Earth System Sciences, 22(4), 2409-2424. doi:10.5194/hess-22-2409-2018Carmona, M., Máñez Costa, M., Andreu, J., Pulido-Velazquez, M., Haro-Monteagudo, D., Lopez-Nicolas, A., & Cremades, R. (2017). Assessing the effectiveness of Multi-Sector Partnerships to manage droughts: The case of the Jucar river basin. Earth’s Future, 5(7), 750-770. doi:10.1002/2017ef000545PALLOTTINO, S., SECHI, G., & ZUDDAS, P. (2005). 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Agricultural Water Management, 155, 113-124. doi:10.1016/j.agwat.2015.03.014Lewandowski, J., Meinikmann, K., & Krause, S. (2020). Groundwater–Surface Water Interactions: Recent Advances and Interdisciplinary Challenges. Water, 12(1), 296. doi:10.3390/w12010296Forrester, J. W. (1968). Industrial Dynamics—After the First Decade. Management Science, 14(7), 398-415. doi:10.1287/mnsc.14.7.398Sušnik, J., Molina, J.-L., Vamvakeridou-Lyroudia, L. S., Savić, D. A., & Kapelan, Z. (2012). Comparative Analysis of System Dynamics and Object-Oriented Bayesian Networks Modelling for Water Systems Management. Water Resources Management, 27(3), 819-841. doi:10.1007/s11269-012-0217-8Mirchi, A., Madani, K., Watkins, D., & Ahmad, S. (2012). Synthesis of System Dynamics Tools for Holistic Conceptualization of Water Resources Problems. Water Resources Management, 26(9), 2421-2442. doi:10.1007/s11269-012-0024-2Simonovic, S. (2002). World water dynamics: global modeling of water resources. 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    Functional evaluation of coronary disease by CT angiography

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    Publisher Copyright: © 2015 American College of Cardiology Foundation.In recent years, several technical developments in the field of cardiac computed tomography (CT) have made possible the extraction of functional information from an anatomy-based examination. Several different lines have been explored and will be reviewed in the present paper, namely: 1) myocardial perfusion imaging; 2) transluminal attenuation gradients and corrected coronary opacification indexes; 3) fractional flow reserve computed from CT; and 4) extrapolation from atherosclerotic plaque characteristics. In view of these developments, cardiac CT has the potential to become in the near future a truly 2-in-1 noninvasive evaluation for coronary artery disease.publishersversionpublishe
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