551 research outputs found

    The endocranial morphology and inner ear of the abelisaurid theropod Aucasaurus garridoi

    Get PDF
    A partial cranial endocast and right inner ear of the Cretaceous abelisaurid dinosaur Aucasaurus garridoi were digitally reconstructed from CT scans. The forebrain, midbrain, and hindbrain resemble the morphology described for the abelisaurids Majungasaurus and Indosaurus. However, Aucasaurus exhibits a floccular process that is relatively larger than that of Majungasaurus. In Aucasaurus the flocculus is enclosed in an 8-shaped floccular recess, similar in shape and size to that observed in Abelisaurus, suggesting that the two Patagonian taxa were capable of a slightly wider range of movements of the head. Here we describe the second inner ear known for the Abelisauridae. The labyrinth of the inner ear is similar in shape and size to the semicircular canals of Majungasaurus, although the lateral semicircular canal is shorter in Aucasaurus.Fil: Paulina Carabajal, Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Provincia del Neuquén. Municipalidad de Plaza Huincul. Museo ; ArgentinaFil: Succar, Cecilia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Provincia del Neuquén. Municipalidad de Plaza Huincul. Museo ; Argentin

    Using Wittgenstein’s family resemblance principle to learn exemplars

    Get PDF
    The introduction of the notion of family resemblance represented a major shift in Wittgenstein’s thoughts on the meaning of words, moving away from a belief that words were well defined, to a view that words denoted less well defined categories of meaning. This paper presents the use of the notion of family resemblance in the area of machine learning as an example of the benefits that can accrue from adopting the kind of paradigm shift taken by Wittgenstein. The paper presents a model capable of learning exemplars using the principle of family resemblance and adopting Bayesian networks for a representation of exemplars. An empirical evaluation is presented on three data sets and shows promising results that suggest that previous assumptions about the way we categories need reopening

    A review of tertiary BIM education for advanced engineering communication with visualization

    Get PDF
    SPECT with Tc-99m-labeled agents is better able to detect viability after nitrate administration. Nitrates induce vasoclilation and may increase blood flow to severely hypoperfused but viable myocardium, thereby enhancing tracer delivery and improving the detection of viability. Quantitative data on the changes in blood flow are lacking in SPECT but can be provided by PET. The aim of the present study was to use PET to evaluate whether nitrate administration increases blood flow to chronically dysfunctional but viable myocardium. Methods: N-13-Ammonia PET was used to quantitatively assess blood flow, and F-18-FDG PET was used as the gold standard to detect viable myocardium. Twenty-five patients with chronic ischemic left ventricular dysfunction underwent N-13-ammonia PET at rest and after nitrate administration. Results: A significant increase in nitrate-enhanced blood flow was observed in viable segments (from 0.55 +/- 0.15 to 0.68 +/- 0.24 mL/min/g, P <0.05). No statistically significant change in blood flow was observed in nonviable segments (0.60 +/- 0.20 vs. 0.55 +/- 0.18 mL/min/g). A ratio of at least 1.1 for nitrate-enhanced flow to resting flow allowed optimal detection of viable myocardium, yielding a sensitivity of 82% with a specificity of 100%. Conclusion: N-13-Ammonia PET showed a significant increase in nitrate-enhanced blood flow in viable myocardium, whereas blood flow remained unchanged after nitrate administration in nonviable myocardium. Nitrate use during myocardial perfusion imaging will lead to improved assessment of myocardial viability

    Building information modelling – A novel parametric modeling approach based on 3D surveys of historic architecture

    Get PDF
    Building Information Modelling (BIM) appears to be the best answer to simplify the traditional process of design, construction, management and maintenance. On the other hand, the intricate reality of the built heritage and the growing need to represent the actual geometry using 3D models collide with the new paradigms of complexity and accuracy, opening a novel operative perspective for restoration and conservation. The management of complexity through BIM requires a new management approach focused on the development of improve the environmental impact cost, reduction and increase in productivity and efficiency the Architecture, Engineering and Construction (AEC) Industry. This structure is quantifiable in morphological and typical terms by establishing levels of development and detail (LoDs) and changes of direction (ReversLoDs) to support the different stages of life cycle (LCM). Starting from different experiences in the field of HBIM, this research work proposes a dynamic parametric modeling approach that involves the use of laser scanning, photogrammetric data and advanced modelling for HBIM

    Macro-BIM adoption: Conceptual structures

    Get PDF
    Building Information Modelling (BIM) concepts and workflows continue to proliferate within organisations, through project teams, and across the whole construction industry. However, both BIM implementation and BIM diffusion are yet to be reliably assessed at market scale. Insufficient research has been conducted to date towards identifying the conceptual structures that would explain and encourage large-scale BIM adoption. This paper introduces a number of macro-adoption models, matrices and charts (Fig. 1). These models can be used to systematically assess BIM adoption across markets, and inform the structured development of country-specific BIM adoption policies. This research is published in two complementary papers combining conceptual structures with data collected from experts across a number of countries. The first paper “Macro-BIM adoption: conceptual structures” delimits the terms used, reviews applicable diffusion models, and clarifies the research methodology. It then introduces five new conceptual constructs for assessing macro-BIM adoption and informing the development of market-scale BIM diffusion policies. The second paper “Macro-BIM adoption: comparative market analysis” employs these concepts and tools to evaluate BIM adoption and analyse BIM diffusion policies across a number of countries. Using online questionnaires and structured interviews, it applies the models, refines the conceptual tools and develops additional assessment metrics. The two papers are complementary and primarily intended to assist policy makers and domain researchers to analyse, develop and improve BIM diffusion policies

    Spin wave excitations in a nanowire spin-torque oscillator with perpendicular magnetic anisotropy

    Full text link
    Spin torque oscillators (STOs) are emerging microwave devices that can potentially be used in spin-logic devices and the next-generation high-speed computing architecture. Thanks to their non-linear nature, STOs are easily tunable by the magnetic field and the dc current. Spin Hall nano-oscillators (SHNOs) are promising types of STOs and most of the current studies focus on localized modes that can be easily excited. Here, we study using micromagnetic simulations, the nature of the spin-torque-induced excitations in nanowire devices made of perpendicular magnetic anisotropy (PMA) material. Our results showed that upon including PMA the excitation of localized and propagating spin wave modes is feasible. We study the nature of the mode excitations as a function of the PMA strength (\text{K}u_u), and the current. Indeed, we estimate a critical value of \text{K}u_u to allow for the excitation of the propagating spin wave. We attribute this mode selectivity between localized and propagating modes to a switch in the sign of the nonlinearity of the system from negative to positive at a non-zero \text{K}u_u which is supported by analytical calculations. Our results provide deep insight into engineering reconfigurable microwave devices for future magnonic and computational applications

    A Semiotic Approach for Guiding the Visualizing of Time and Space in Enterprise Models

    Get PDF
    Part 2: Organizational Semiotics and ApplicationsInternational audienceEven if geographical aspects such as location are included already in the Zachman framework (as the where-perspective), it is not common to have detailed geographical aspects included in enterprise models. Cartography is the science of visualizing geographical information in maps. Traditionally the field has not included conceptual relationships that you find in enterprise models. Both cartography and enterprise modelling have developed guidelines for obtaining high quality visualizations. SEQUAL is a quality framework developed for understanding quality of models and modelling languages based on semiotic theory. In cartography such frameworks are not common. An adaptation of SEQUAL in the context of cartographic maps called MAPQUAL has been presented earlier. Differences between quality of maps and quality of conceptual models, pointing to guidelines for combined representations have been performed, and we try in this paper to investigate the utility of these guidelines in a simple trial. The result of the trial is presented, indicating that it is possible to represent conceptual, temporal, and spatial aspects in the same models in many ways, but that the choice of main perspective should depend on participant appropriateness

    Maturity matrix assessment : evaluation of energy efficiency strategies in Brussels historic residential stock

    Get PDF
    Energy retrofitting of historic or existing buildings is a challenge that it has not yet been properly solved. Multiple projects and methodologies are published every day but neither of them with the holistic approach that will assure success since the design phase. Nevertheless, these buildings play a key role in the achievement of the ambitious energy saving and greenhouse gas reduction targets that Europe has fixed for 2020 and 2050. Research has demonstrated that the impact in terms of decrease of energy use and CO2 will be strong, considering that, in Europe, 80% of the 2030 building stock already exists and 30% are historical buildings. To achieve these goals, reliable data about energy consumption, building components and systems performance of the existing building stock is needed. With the residential stock occupying a 75% of Europe’s floor space, this becomes a difficult task as this stock is never considered as a whole. Its components are installed, serviced and maintained by different companies and in different stages without a holistic approach to the overall building operation. The result is a lack of energy efficiency and feedback of the solutions implemented once the buildings are refurbished. This paper presents a pre-assessment methodology to tackle the energy retrofitting of historic and existing residential buildings based in the Maturity Matrix Assessment. The maturity of the implementation of energy efficiency measures in Brussels historic residential stock is evaluated to measure the gap between the “as is” and “to be” and define future appropriate strategies. The matrix synthetizes appropriate strategies for this specific stock that provides a global map of the problematic, requirements and solutions
    corecore