847 research outputs found

    Conduite d'un Robot Mobile Opto-guidé Par Logiciels Temps-Réel Open-Source Démonstrateur du projet RNTL Cléopatre

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    National audienceLe travail présenté ici a été réalisé dans le cadre du projet Cléopatre1, projet national de R&D dans le domaine des technologies logicielles dédiées aux applications temps-réel, terminé en juin 2005. Ce projet avait pour finalité la conception d'un système d'exploitation temps réel baptisé « système Cléopatre » à code source ouvert, gratuit et téléchargeable à partir d'un site public de façon à en faciliter la diffusion. Ce système d'exploitation temps réel a la particularité de se présenter sous forme d'un assemblage de composants sélectionnables par l'utilisateur. Ces derniers peuvent être définis comme des briques logicielles disponibles sur les étagères d'une bibliothèque et implémentant des mécanismes novateurs principalement issus de la recherche en ordonnancement temps réel. Nous présentons le démonstrateur de ce projet, un AGV (Automated Guided Vehicle) conduit en temps-réel par l'O.S. Cléopatre. L'objectif était d'évaluer ses performances d'un point de vue temporel, le gain engendré par l'approche composant en termes d'empreinte mémoire et d'accessibilité mais aussi vérifier l'inter-opérabilité des composants logiciels développés. L'application mise en œuvre consiste à conduire cet AGV opto-guidé muni de son informatique embarquée, en exécutant en temps-réel des ordres de mission émis par une liaison sans fil à partir d'une station de supervision

    Long-Range Transformer Architectures for Document Understanding

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    Since their release, Transformers have revolutionized many fields from Natural Language Understanding to Computer Vision. Document Understanding (DU) was not left behind with first Transformer based models for DU dating from late 2019. However, the computational complexity of the self-attention operation limits their capabilities to small sequences. In this paper we explore multiple strategies to apply Transformer based models to long multi-page documents. We introduce 2 new multi-modal (text + layout) long-range models for DU. They are based on efficient implementations of Transformers for long sequences. Long-range models can process whole documents at once effectively and are less impaired by the document's length. We compare them to LayoutLM, a classical Transformer adapted for DU and pre-trained on millions of documents. We further propose 2D relative attention bias to guide self-attention towards relevant tokens without harming model efficiency. We observe improvements on multi-page business documents on Information Retrieval for a small performance cost on smaller sequences. Relative 2D attention revealed to be effective on dense text for both normal and long-range models.Comment: Conference: ICDAR 2023 Workshops on Document Analysis and Recognitio

    Primary structure of a high Mr form of rat atrial natriuretic factor

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    AbstractDuring the purification of rat atrial natriuretic factor (ANF), low, intermediate and high Mr forms were observed. In this report we describe the purification and amino acid sequence of a 73 residue peptide containing at its C-terminus the previously sequenced 33 amino acid ANF peptide. The cleabage necessary to produce the 33 amino acid ANF from the 73 amino acid precursor occurs at a Leuî—¸Leu bond. We also report the amino acid composition of an even longer form of ANF containing about 103 residues, in which the extension is amino terminal to the 73 peptide. A computer data bank search showed that the determined sequence is a novel one and is not homologous to any known proteins or segment thereof. The natriuretic activity of the 73 amino acid form when compared to that of a synthetic ANF peptide, comprising the sequence of the last 26 amino acids of ANF, was found to be slightly lower

    Purification of three rat atrial natriuretic factors and their amino acid composition

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    AbstractA natriuretic factor has been described in the specific granules of rat atria. We have purified three factors which seem to be low-Mr peptides. They have been purified by means of acid extraction, octadecyl Sep-Pak cartridges, and chromatography on Bio-Gel P-10, CM Bio-Gel A, Mono S and reverse-phase high-performance liquid chromatography columns. The factors contain 26, 31 and 33 amino acids and may have been partially degraded during isolation. They are all 3 biologically active and the shorter one is the most active with a specific activity of 450000 units/mg

    Evidence for intracellular generation of angiotensin II in rat juxtaglomerular cells

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    AbstractThe formation of the vasoactive peptide angiotensin II (AII) is dependent on the sequential action of two enzymes, renin and angiotensin converting enzyme (ACE), on the substrate angiotensinogen. Although the renin-producing cells of the kidney do not express angiotensinogen, they contain large amounts of AII in the same storage granules that contain renin. When renin expression is suppressed in these cells, AII also disappears. In the current study, we have tested whether the renin-associated disappearance of AII in renal juxtaglomerular (JG) cells is due to a renin-dependent down-regulation of granule biosynthesis and whether receptor-mediated internalization of AII could account for its concentration in these cells. Our results support a model whereby AII peptides are generated within JG cells, presumably by a mechanism which involves the action of endogenous renin on internalized, exogenous angiotensinogen

    Lack of dietary polyunsaturated fatty acids causes synapse dysfunction in the drosophila visual system

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    Polyunsaturated fatty acids (PUFAs) are essential nutrients for animals and necessary for the normal functioning of the nervous system. A lack of PUFAs can result from the consumption of a deficient diet or genetic factors, which impact PUFA uptake and metabolism. Both can cause synaptic dysfunction, which is associated with numerous disorders. However, there is a knowledge gap linking these neuronal dysfunctions and their underlying molecular mechanisms. Because of its genetic manipulability and its easy, fast, and cheap breeding, Drosophila melanogaster has emerged as an excellent model organism for genetic screens, helping to identify the genetic bases of such events. As a first step towards the understanding of PUFA implications in Drosophila synaptic physiology we designed a breeding medium containing only very low amounts of PUFAs. We then used the fly’s visual system, a well-established model for studying signal transmission and neurological disorders, to measure the effects of a PUFA deficiency on synaptic function. Using both visual performance and eye electrophysiology, we found that PUFA deficiency strongly affected synaptic transmission in the fly’s visual system. These defects were rescued by diets containing omega-3 or omega-6 PUFAs alone or in combination. In summary, manipulating PUFA contents in the fly’s diet was powerful to investigate the role of these nutrients on the fly´s visual synaptic function. This study aims at showing how the first visual synapse of Drosophila can serve as a simple model to study the effects of PUFAs on synapse function. A similar approach could be further used to screen for genetic factors underlying the molecular mechanisms of synaptic dysfunctions associated with altered PUFA levels

    Purification of three rat atrial natriuretic factors and their amino acid composition

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    AbstractA natriuretic factor has been described in the specific granules of rat atria. We have purified three factors which seem to be low-Mr peptides. They have been purified by means of acid extraction, octadecyl Sep-Pak cartridges, and chromatography on Bio-Gel P-10, CM Bio-Gel A, Mono S and reverse-phase high-performance liquid chromatography columns. The factors contain 26, 31 and 33 amino acids and may have been partially degraded during isolation. They are all 3 biologically active and the shorter one is the most active with a specific activity of 450000 units/mg

    Altered density of glomerular binding sites for atrial natriuretic factor in bile duct-ligated rats with ascites

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    The renal response to atrial natriuretic factor is blunted in cirrhosis with ascites. This might be due to alterations of renal receptors for atrial natriuretic factor. Therefore density and affinity of glomerular atrial natriuretic factor binding sites of bile duct-ligated rats with ascites (n = 10) and of sham-operated controls (n = 10) were determined. Glomerular atrial natriuretic factor binding sites were identified to be of the B-(biologically active) and C-(clearance) receptor type. Discrimination and quantitative determination of B and C receptors for atrial natriuretic factor were achieved by displacement experiments with atrial natriuretic factor(99-126) or des(18-22)atrial natriuretic factor(4-23), an analogue binding to C receptors only. Density of total glomerular atrial natriuretic factor binding sites was significantly increased in bile duct-ligated rats (3,518 ± 864 vs. 1,648 ± 358 fmol/mg protein; p < 0.05). This was due to a significant increase of C-receptor density (3,460 ± 866 vs. 1,486 ± 363 fmol/mg protein; p < 0.05), whereas density of B receptors was not significantly different in bile duct-ligated rats (58 ± 11 vs. 162 ± 63 fmol/mg protein). Affinity of atrial natriuretic factor to its glomerular binding sites did not differ significantly between both groups. These data suggest that an altered glomerular atrial natriuretic factor receptor density could be involved in the renal resistance to atrial natriuretic factor in cirrhosis with ascites
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