236 research outputs found

    Multitask Learning on Graph Neural Networks: Learning Multiple Graph Centrality Measures with a Unified Network

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    The application of deep learning to symbolic domains remains an active research endeavour. Graph neural networks (GNN), consisting of trained neural modules which can be arranged in different topologies at run time, are sound alternatives to tackle relational problems which lend themselves to graph representations. In this paper, we show that GNNs are capable of multitask learning, which can be naturally enforced by training the model to refine a single set of multidimensional embeddings Rd\in \mathbb{R}^d and decode them into multiple outputs by connecting MLPs at the end of the pipeline. We demonstrate the multitask learning capability of the model in the relevant relational problem of estimating network centrality measures, focusing primarily on producing rankings based on these measures, i.e. is vertex v1v_1 more central than vertex v2v_2 given centrality cc?. We then show that a GNN can be trained to develop a \emph{lingua franca} of vertex embeddings from which all relevant information about any of the trained centrality measures can be decoded. The proposed model achieves 89%89\% accuracy on a test dataset of random instances with up to 128 vertices and is shown to generalise to larger problem sizes. The model is also shown to obtain reasonable accuracy on a dataset of real world instances with up to 4k vertices, vastly surpassing the sizes of the largest instances with which the model was trained (n=128n=128). Finally, we believe that our contributions attest to the potential of GNNs in symbolic domains in general and in relational learning in particular.Comment: Published at ICANN2019. 10 pages, 3 Figure

    Ergodicity and digital texts

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    Na passagem do texto físico para o texto digital ocorre uma quebra da linearidade da página impressa, que afecta a forma como a recepção se alia à produção através da performatividade característica das novas narrativas. A ruptura do limite material do texto, permitida pela hipertextualidade, obriga a uma construção de sentidos diferente, que assenta na exploração de um texto maior. A introdução do hipermedia vem depois ampliar e complexificar a ideia de hipertextualidade, ao fazer convergir linguagens diversas, num processo interactivo que se assemelha ao processo da própria criação. A partir de estímulos e aberturas do trabalho digital, os textos ergódicos constroem a imaterialidade da significação em espaços singularizados de materialidade algorítmica. Perante um texto destituído de corpo próprio ou único, pretende-se discutir a forma como a textualidade electrónica assiste a esta desmaterialização e a conduz, e como o discurso hipermedia se desloca entre linguagens e suportes multimédia diferentes.ABSTRACT: Whilst breaking the linearity of the printed page, the passage from the physical text to a digital one has blurred the limits between reception and production and has shaped different narrative performances. Hypertextuality has shattered the limits of the text and has simultaneously required the construction of meaning by exploring a major text. Eventually, hypermedia has amplified and complexified that hypertextuality by being able to converge diverse languages, in an interactive process that resembles the actual creation activity. In response to the nodes and stimuli of the digital work, ergodic texts coexist within a customized space of algorithmic materiality and signification immateriality. In this paper we want to discuss how the bodiless but crowded electronic textuality leads this dematerialization as the hypermedia discourse flickers among different languages and multimedia devices.info:eu-repo/semantics/publishedVersio

    Soybean plant metabolism under water deficit and xenobiotic and antioxidant agent application.

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    The aim was to evaluate the interactive eects on biochemistry and physiology of soybean plants exposed to simultaneous xenobiotic and water deficit stresses, and the possible attenuation of plant damage by an antioxidant agent. Soybean plants were submitted to eight different soil water potentials, in two experiments (first experiment: 􀀀0.96, 􀀀0.38, 􀀀0.07, 􀀀0.02MPa, and second experiment: 􀀀3.09, 􀀀1.38, 􀀀0.69, 􀀀0.14 MPa), xenobiotic, and antioxidant agent applications. Was observed a reduction in water status, gas exchange, photosynthetic pigments, photosystem II quantum yield, and increased leaf temperature in plants under low water availability. Water deficit also induced oxidative stress by the increased production of reactive oxygen species, cellular and molecular damage, and induction of the antioxidant defense metabolism, reduction of gas exchange, water status, and photosynthetic eciency. The xenobiotic application also caused changes, with deleterious eects more pronounced in low soil water availability, mainly the reactive oxygen species production, consequently the antioxidant activity, and the oxidative damages. This indicates dierent responses to the combination of stresses. Antioxidant enzyme activity was reduced by the application of the antioxidant agent. Principal Component Analysis showed a relation with the antioxidant agent and reactive oxygen species, which is probably due to signaling function, and with defense antioxidant system, mainly glutathione, represented by thiols. Keywords: oxidative stress; oxidative damages; physiology; biochemistry; antioxidant defense; soil water potential; biostimulan

    Pemphigus autoimmunity: Hypotheses and realities

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    The goal of contemporary research in pemphigus vulgaris and pemphigus foliaceus is to achieve and maintain clinical remission without corticosteroids. Recent advances of knowledge on pemphigus autoimmunity scrutinize old dogmas, resolve controversies, and open novel perspectives for treatment. Elucidation of intimate mechanisms of keratinocyte detachment and death in pemphigus has challenged the monopathogenic explanation of disease immunopathology. Over 50 organ-specific and non-organ-specific antigens can be targeted by pemphigus autoimmunity, including desmosomal cadherins and other adhesion molecules, PERP cholinergic and other cell membrane (CM) receptors, and mitochondrial proteins. The initial insult is sustained by the autoantibodies to the cell membrane receptor antigens triggering the intracellular signaling by Src, epidermal growth factor receptor kinase, protein kinases A and C, phospholipase C, mTOR, p38 MAPK, JNK, other tyrosine kinases, and calmodulin that cause basal cell shrinkage and ripping desmosomes off the CM. Autoantibodies synergize with effectors of apoptotic and oncotic pathways, serine proteases, and inflammatory cytokines to overcome the natural resistance and activate the cell death program in keratinocytes. The process of keratinocyte shrinkage/detachment and death via apoptosis/oncosis has been termed apoptolysis to emphasize that it is triggered by the same signal effectors and mediated by the same cell death enzymes. The natural course of pemphigus has improved due to a substantial progress in developing of the steroid-sparing therapies combining the immunosuppressive and direct anti-acantholytic effects. Further elucidation of the molecular mechanisms mediating immune dysregulation and apoptolysis in pemphigus should improve our understanding of disease pathogenesis and facilitate development of steroid-free treatment of patients

    Position Statement on Atopic Dermatitis in Sub-Saharan Africa:current status and roadmap

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    The first International Society of Atopic Dermatitis (ISAD) global meeting dedicated to atopic dermatitis (AD) in Sub-Saharan Africa (SSA) was held in Geneva, Switzerland in April 2019. A total of 30 participants were present at the meeting, including those from 17 SSA countries, representatives of the World Health Organization (WHO), the International Foundation for Dermatology (IFD) (a committee of the International League of Dermatological Societies, ILDS www.ilds.org), the Fondation pour la Dermatite Atopique, as well as specialists in telemedicine, artificial intelligence and therapeutic patient education (TPE)
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