4,793 research outputs found

    Modeling and Testing a Family of Surgical Robots: An Experience Report

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    Safety-critical applications often use dependability cases to validate that specified properties are invariant, or to demonstrate a counter example showing how that property might be violated. However, most dependability cases are written with a single product in mind. At the same time, software product lines (families of related software products) have been studied with the goal of modeling variability and commonality, and building family based techniques for both analysis and testing. However, there has been little work on building an end to end dependability case for a software product line (where a property is modeled, a counter example is found and then validated as a true positive via testing), and none that we know of in an emerging safety-critical domain, that of robotic surgery. In this paper, we study a family of surgical robots, that combine hardware and software, and are highly configurable, representing over 1300 unique robots. At the same time, they are considered safety-critical and should have associated dependability cases. We perform a case study to understand how we can bring together lightweight formal analysis, feature modeling, and testing to provide an end to end pipeline to find potential violations of important safety properties. In the process, we learned that there are some interesting and open challenges for the research community, which if solved will lead towards more dependable safety-critical cyber-physical systems

    Neurogenesis-mediated forgetting minimizes proactive interference.

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    Established memories may interfere with the encoding of new memories, particularly when existing and new memories overlap in content. By manipulating levels of hippocampal neurogenesis, here we show that neurogenesis regulates this form of proactive interference. Increasing hippocampal neurogenesis weakens existing memories and, in doing so, facilitates the encoding of new, conflicting (but not non-conflicting) information in mice. Conversely, decreasing neurogenesis stabilizes existing memories, and impedes the encoding of new, conflicting information. These results suggest that reduced proactive interference is an adaptive benefit of neurogenesis-induced forgetting

    Diets high in n-3 fatty acids are associated with lower arterial stiffness in patients with rheumatoid arthritis: a latent profile analysis

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    Supplementation with n-3 fatty acids can influence inflammation and markers of arterial stiffness that are increased in patients with rheumatoid arthritis (RA). However, it is unknown whether specific patterns of dietary fatty acid intake are similarly associated. In a longitudinal study, eighty-six RA patients reported their dietary intake and had arterial stiffness measured using the augmentation index (AIx) at baseline and 8 months. Latent profile analysis (LPA) was performed to characterise patterns of fatty acid intake using sixteen major fatty acids. Models for two to six profiles were compared using the Akaike and Bayesian information criteria. Associations between AIx and the profiles were adjusted for age, sex, disease activity, fish oil supplementation, medications, physical activity and socio-economic status. LPA identified five distinct profiles. Profile 1 subjects (n 7) reported significantly higher intake of palmitoleic acid (16 : 1), arachidonic acid (20 : 4n-6), EPA (20 : 5n-3), DHA (22 : 6n-3) and docosapentaenoic acid (22 : 5n-3) (

    Deep Lesion Graphs in the Wild: Relationship Learning and Organization of Significant Radiology Image Findings in a Diverse Large-scale Lesion Database

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    Radiologists in their daily work routinely find and annotate significant abnormalities on a large number of radiology images. Such abnormalities, or lesions, have collected over years and stored in hospitals' picture archiving and communication systems. However, they are basically unsorted and lack semantic annotations like type and location. In this paper, we aim to organize and explore them by learning a deep feature representation for each lesion. A large-scale and comprehensive dataset, DeepLesion, is introduced for this task. DeepLesion contains bounding boxes and size measurements of over 32K lesions. To model their similarity relationship, we leverage multiple supervision information including types, self-supervised location coordinates and sizes. They require little manual annotation effort but describe useful attributes of the lesions. Then, a triplet network is utilized to learn lesion embeddings with a sequential sampling strategy to depict their hierarchical similarity structure. Experiments show promising qualitative and quantitative results on lesion retrieval, clustering, and classification. The learned embeddings can be further employed to build a lesion graph for various clinically useful applications. We propose algorithms for intra-patient lesion matching and missing annotation mining. Experimental results validate their effectiveness.Comment: Accepted by CVPR2018. DeepLesion url adde

    Hyperboloidal discontinuous time-symmetric numerical algorithm with higher order jumps for gravitational self-force computations in the time domain

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    Within the next decade the Laser Interferometer Space Antenna (LISA) is due to be launched, providing the opportunity to extract physics from stellar objects and systems, such as \textit{Extreme Mass Ratio Inspirals}, (EMRIs) otherwise undetectable to ground based interferometers and Pulsar Timing Arrays (PTA). Unlike previous sources detected by the currently available observational methods, these sources can \textit{only} be simulated using an accurate computation of the gravitational self-force. Whereas the field has seen outstanding progress in the frequency domain, metric reconstruction and self-force calculations are still an open challenge in the time domain. Such computations would not only further corroborate frequency domain calculations and models, but also allow for full self-consistent evolution of the orbit under the effect of the self-force. Given we have \textit{a priori} information about the local structure of the discontinuity at the particle, we will show how to construct discontinuous spatial and temporal discretisations by operating on discontinuous Lagrange and Hermite interpolation formulae and hence recover higher order accuracy. In this work we demonstrate how this technique in conjunction with well-suited gauge choice (hyperboloidal slicing) and numerical (discontinuous collocation with time symmetric) methods can provide a relatively simple method of lines numerical algorithm to the problem. This is the first of a series of papers studying the behaviour of a point-particle prescribing circular geodesic motion in Schwarzschild in the \textit{time domain}. In this work we describe the numerical machinery necessary for these computations and show not only our work is capable of highly accurate flux radiation measurements but it also shows suitability for evaluation of the necessary field and it's derivatives at the particle limit

    NIR jets from a clustered region of massive star formation: Morphology and composition in the IRAS 18264-1152 region

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    Context. Massive stars play crucial roles in determining the physical and chemical evolution of galaxies. However, they form deeply embedded in their parental clouds, making it challenging to directly observe these stars and their immediate environments. It is known that accretion and ejection processes are intrinsically related, thus observing the massive protostellar outflows can provide crucial information about the processes governing massive star formation very close to the central engine. Aims. We aim to probe the IRAS 18264-1152 (also known as G19.88-0.53) high-mass star-forming complex in the near infrared (NIR) through its molecular hydrogen (H2) jets to analyse the morphology and composition of the line emitting regions and to compare with other outflow tracers. Methods. We observed the H2 NIR jets via K-band (1.9 2.5 μm) observations obtained with the integral field units VLT/SINFONI and VLT/KMOS. VLT/SINFONI provides the highest NIR angular resolution achieved so far for the central region of IRAS 18264-1152 (∼0.2). We compared the geometry of the NIR outflows with that of the associated molecular outflow, probed by CO (2-1) emission mapped with the Submillimeter Array. Results. We identify nine point sources in the SINFONI and KMOS fields of view. Four of these display a rising continuum in the K-band and are Brγ emitters, revealing that they are young, potentially jet-driving sources. The spectro-imaging analysis focusses on the H2 jets, for which we derived visual extinction, temperature, column density, area, and mass. The intensity, velocity, and excitation maps based on H2 emission strongly support the existence of a protostellar cluster in this region, with at least two (and up to four) different large-scale outflows, found through the NIR and radio observations. We compare our results with those found in the literature and find good agreement in the outflow morphology. This multi-wavelength comparison also allows us to derive a stellar density of ∼4000 stars pc-3. Conclusions. Our study reveals the presence of several outflows driven by young sources from a forming cluster of young, massive stars, demonstrating the utility of such NIR observations for characterising massive star-forming regions. Moreover, the derived stellar number density together with the geometry of the outflows suggest that stars can form in a relatively ordered manner in this cluster

    Lagochilascariasis leading to severe involvement of ocular globes, ears and meninges

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    A case report of a 31 year-old woman from Paraíba State (North-Eastern Brazil) that presented severe involvement of ocular globes, ears and meninges. Diagnosis was established after enucleation of her left eye, when adult worms were seen in the midst of a granulomatous inflammatory process. Her response to the initial treatment with levamisole and cambendazole was good, but there was a relapse after the fifth month of treatment even with maintenance doses of both medications. She later received ivermectin and albendazol and responded well.Paciente do sexo feminino, com 31 anos, procedente da Paraíba, apresentava envolvimento severo de ambos os globos oculares, com perda da visão à esquerda, comprometimento da audição e das meninges. Após enucleação do olho esquerdo fragmento de helminto identificado como Lagochilascaris minor foi observado em processo inflamatório granulomatoso. Inicialmente a paciente foi tratada com levamisol e cambendazol, com bom resultado. Verificou-se, todavia, piora do quadro após cinco meses, com eliminação de larvas do ascarídeo em lesão presente na órbita esquerda, embora a medicação fosse mantida com administração periódica. Houve boa resposta terapêutica, com regressão do quadro, após substituição dos anti-helmínticos anteriores pela associação ivermectina e albendazol
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