49 research outputs found

    The role of electrostriction on the stability of dielectric elastomer actuators

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    In the field of soft dielectric elastomers, the notion electrostriction indicates the dependency of the permittivity on strain. The present paper is aimed at investigating the effects of electrostriction onto the stability behaviour of homogeneous electrically activated dielectric elastomer actuators. In particular, three objectives are pursued and achieved: i) the description of the phenomenon within the general nonlinear theory of electroelasticity; ii) the application of the recently proposed theory of bifurcation for electroelastic bodies in order to determine its role on the onset of electromechanical and diffuse-mode instabilities in prestressed or prestretched dielectric layers; iii) the analysis of band-localization instability in homogeneous dielectric elastomers. Results for a typical soft acrylic elastomer show that electrostriction is responsible for an enhancement towards diffuse-mode instability, while it represents a crucial property - necessarily to be taken into account - in order to provide a solution to the problem of electromechanical band-localization, that can be interpreted as a possible reason of electric breakdown. A comparison between the buckling stresses of a mechanical compressed slab and the electrically activated counterpart concludes the paper

    Distributed workflows with Jupyter

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    The designers of a new coordination interface enacting complex workflows have to tackle a dichotomy: choosing a language-independent or language-dependent approach. Language-independent approaches decouple workflow models from the host code's business logic and advocate portability. Language-dependent approaches foster flexibility and performance by adopting the same host language for business and coordination code. Jupyter Notebooks, with their capability to describe both imperative and declarative code in a unique format, allow taking the best of the two approaches, maintaining a clear separation between application and coordination layers but still providing a unified interface to both aspects. We advocate the Jupyter Notebooks’ potential to express complex distributed workflows, identifying the general requirements for a Jupyter-based Workflow Management System (WMS) and introducing a proof-of-concept portable implementation working on hybrid Cloud-HPC infrastructures. As a byproduct, we extended the vanilla IPython kernel with workflow-based parallel and distributed execution capabilities. The proposed Jupyter-workflow (Jw) system is evaluated on common scenarios for High Performance Computing (HPC) and Cloud, showing its potential in lowering the barriers between prototypical Notebooks and production-ready implementations

    Analysis of HIV quasispecies and virological outcome of an HIV D+/R+ kidney–liver transplantation

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    Introduction: Transplantation among HIV positive patients may be a valuable therapeutic intervention. This study involves an HIV D+/R+ kidney–liver transplantation, where PBMC-associated HIV quasispecies were analyzed in donor and transplant recipients (TR) prior to transplantation and thereafter, together with standard viral monitoring. Methods: The donor was a 54 year of age HIV infected woman: kidney and liver recipients were two HIV infected men, aged 49 and 61. HIV quasispecies in PBMC was analyzed by ultra-deep sequencing of V3 env region. During TR follow-up, plasma HIV-1 RNA, HIV-1 DNA in PBMC, analysis of proviral integration sites and drug-resistance genotyping were performed. Other virological and immunological monitoring included CMV and EBV DNA quantification in blood and CD4 T cell counts. Results: Donor and TR were all ART-HIV suppressed at transplantation. Thereafter, TR maintained a nearly suppressed HIV-1 viremia, but HIV-1 RNA blips and the increase of proviral integration sites in PBMC attested some residual HIV replication. A transient peak in HIV-1 DNA occurred in the liver recipient. No major changes of drug-resistance genotype were detected after transplantation. CMV and EBV transient reactivations were observed only in the kidney recipient, but did not require specific treatment. CD4 counts remained stable. No intermixed quasispecies between donor and TR was observed at transplantation or thereafter. Despite signs of viral evolution in TR, HIV genetic heterogeneity did not increase over the course of the months of follow up. Conclusions: No evidence of HIV superinfection was observed in the donor nor in the recipients. The immunosuppressive treatment administrated to TR did not result in clinical relevant viral reactivations

    Recording provenance of workflow runs with RO-Crate

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    Recording the provenance of scientific computation results is key to the support of traceability, reproducibility and quality assessment of data products.Several data models have been explored to address this need, providing representations of workflow plans and their executions as well as means of packaging the resulting information for archiving and sharing.However, existing approaches tend to lack interoperable adoption across workflow management systems.In this work we present Workflow Run RO-Crate, an extension of RO-Crate (Research Object Crate) and Schema.org to capture the provenance of the execution of computational workflows at different levels of granularity and bundle together all their associated objects (inputs, outputs, code, etc.).The model is supported by a diverse, open community that runs regular meetings, discussing development, maintenance and adoption aspects.Workflow Run RO-Crate is already implemented by several workflow management systems, allowing interoperable comparisons between workflow runs from heterogeneous systems.We describe the model, its alignment to standards such as W3C PROV, and its implementation in six workflow systems.Finally, we illustrate the application of Workflow Run RO-Crate in two use cases of machine learning in the digital image analysis domain.A corresponding RO-Crate for this article is at https://w3id.org/ro/doi/10.5281/zenodo.1036898

    Epilessie del lobo occipitale

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    Vengono presentate le diverse forme di epilessie occipitali dell'infanzia e dell'adolescenza, con le specifiche caratterizzazioni cliniche, elettroencefalografiche. Viene discussa la terapia e la prognosi delle singole forme

    ANORESSIA NERVOSA E NUTRIZIONE

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    Nell'ambito dei disturbi del comportamento alimentare in et\ue0 evolutiva spesso \ue8 necessario ricorrere ad interventi forzati di rialimentazione tramite sondino naso-gastrico o via parenterale. Si discutono dunque i vantaggi e gli svantaggi di tali intervent

    CAPIO: a Middleware for Transparent I/O Streaming in Data-Intensive Workflows

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    With the increasing amount of digital data available for analysis and simulation, the class of I/O-intensive HPC workflows is fated to quickly expand, further exacerbating the performance gap between computing, memory, and storage technologies. This paper introduces CAPIO (Cross-Application Programmable I/O), a middleware capable of injecting I/O streaming capabilities into file-based workflows, improving the computation-I/O overlap without the need to change the application code. The contribution is twofold: 1) at design time, a new I/O coordination language allows users to annotate workflow data dependencies with synchronization semantics; 2) at run time, a user-space middleware automatically and transparently to the user turns a workflow batch execution into a streaming execution according to the semantics expressed in the configuration file. CAPIO has been tested on synthetic benchmarks simulating typical workflow I/O patterns and two real-world workflows. Experiments show that CAPIO reduces the execution time by 10% to 66% for data-intensive workflows that use the file system as a communication medium

    [Neuromuscular assessment and postural examination in patients with TMJ condylo-meniscal incoordination].

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    The neuromuscular system plays a primary role in the development of a myofascial syndrome of the temporomandibular joint. Patients suffering from this disease very often show changes in muscular functions. In biomechanical clinical pictures of temporomandibular myofascial syndrome the motor apparatus is involved only in the second stage. In order to determine the efficiency of the motor apparatus and to schedule a physiotherapeutic treatment program to improve condylar-meniscus coordination of the joint, an analysis of muscular function associated with postural examination has been performed, and this with a view to evidence possible skeletal changes, with particular regard to the spine. The study has been carried out in a group of healthy individuals in front of an other group of patients affected by the pathology mentioned
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