861 research outputs found

    A survey of adaptive control technology in robotics

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    Previous work on the adaptive control of robotic systems is reviewed. Although the field is relatively new and does not yet represent a mature discipline, considerable attention has been given to the design of sophisticated robot controllers. Here, adaptive control methods are divided into model reference adaptive systems and self-tuning regulators with further definition of various approaches given in each class. The similarity and distinct features of the designed controllers are delineated and tabulated to enhance comparative review

    Towards a Robuster Interpretive Parsing

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    The input data to grammar learning algorithms often consist of overt forms that do not contain full structural descriptions. This lack of information may contribute to the failure of learning. Past work on Optimality Theory introduced Robust Interpretive Parsing (RIP) as a partial solution to this problem. We generalize RIP and suggest replacing the winner candidate with a weighted mean violation of the potential winner candidates. A Boltzmann distribution is introduced on the winner set, and the distribution’s parameter TT is gradually decreased. Finally, we show that GRIP, the Generalized Robust Interpretive Parsing Algorithm significantly improves the learning success rate in a model with standard constraints for metrical stress assignment

    PDB51 DRUG USE FOR DIABETES MELLITUSTYPE 2 AND ITS COMPLICATIONS IN SLOVAKIA

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    Locally Constrained Homomorphisms on Graphs of Bounded Treewidth and Bounded Degree

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    A homomorphism from a graph G to a graph H is locally bijective, surjective, or injective if its restriction to the neighborhood of every vertex of G is bijective, surjective, or injective, respectively. We prove that the problems of testing whether a given graph G allows a homomorphism to a given graph H that is locally bijective, surjective, or injective, respectively, are NP-complete, even when G has pathwidth at most 5, 4 or 2, respectively, or when both G and H have maximum degree 3. We complement these hardness results by showing that the three problems are polynomial-time solvable if G has bounded treewidth and in addition G or H has bounded maximum degree

    Intracellular neutralization of viral infection in polarized epithelial cells by neonatal Fc receptor (FcRn)-mediated IgG transport

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    IgG was traditionally thought to neutralize virions by blocking their attachment to or penetration into mucosal epithelial cells, a common site of exposure to viruses. However, we describe an intracellular neutralizing action for an influenza hemagglutinin-specific monoclonal antibody, Y8-10C2 (Y8), which has neutralizing activity only at an acidic pH. When Y8 was applied to the basolateral surface of Madin–Darby canine kidney cells expressing the rat neonatal Fc receptor for IgG (FcRn), it significantly reduced viral replication following apical exposure of the cell monolayer to influenza virus. Virus neutralization by Y8 mAb was dependent on FcRn expression and its transport of IgG. As both FcRn and Y8 mAb bind their partners only at acidic pH, the Y8 mAb is proposed to carry out its antiviral activity intracellularly. Furthermore, the virus, Y8 mAb, and FcRn colocalized within endosomes, possibly inhibiting the fusion of viral envelopes with endosomal membranes during primary uncoating, and preventing the accumulation of the neutralized viral nucleoprotein antigen in the nucleus. Prophylactic administration of Y8 mAb before viral challenge in WT mice, but not FcRn-KO mice, conferred protection from lethality, prevented weight loss, resulted in a significant reduction in pulmonary virus titers, and largely reduced virus-induced lung pathology. Thus, this study reveals an intracellular mechanism for viral neutralization in polarized epithelial cells that is dependent on FcRn-mediated transport of neutralizing IgG

    Advanced development for space robotics with emphasis on fault tolerance

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    This paper describes the ongoing work in fault tolerance at the University of Texas at Austin. The paper describes the technical goals the group is striving to achieve and includes a brief description of the individual projects focusing on fault tolerance. The ultimate goal is to develop and test technology applicable to all future missions of NASA (lunar base, Mars exploration, planetary surveillance, space station, etc.)

    Design of an airlift loop bioreactor and pilot scales studies with fluidic oscillator induced microbubbles for growth of a microalgae Dunaliella salina

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    This study was conducted to test the feasibility of growing microalgae on steel plant exhaust gas, generated from the combustion of offgases from steel processing, which has a high CO content. Two field trials of batch algal biomass growth, mediated by microbubble transfer processes in an airlift loop bioreactor showed only steady growth of biomass with 100% survival rate. The gas analysis of CO uptake in the 2200L bioreactor showed a specific uptake rate of 0.1g/L/h, an average 14% of the CO available in the exhaust gas with a 23% composition of CO. This uptake led to a steady production of chlorophyll and total lipid constituency in the bioreactor, and an accelerating exponential growth rate of biomass, with a top doubling time of 1.8days. The gas analysis also showed anti-correlation of CO uptake and O production, which along with the apparent stripping of the O to the equilibrium level by the microbubbles, strongly suggests that the bioreactor is not mass transfer limited, nor O inhibited. Removing O inhibition results in high growth rates and high density of biomass. © 2011 Elsevier Ltd

    The Chicken Yolk Sac IgY Receptor, a Mammalian Mannose Receptor Family Member, Transcytoses IgY across Polarized Epithelial Cells

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    In mammals the transfer of passive immunity from mother to young is mediated by the MHC-related receptor FcRn, which transports maternal IgG across epithelial cell barriers. In birds, maternal IgY in egg yolk is transferred across the yolk sac to passively immunize chicks during gestation and early independent life. The chicken yolk sac IgY receptor (FcRY) is the ortholog of the mammalian phospholipase A2 receptor, a mannose receptor family member, rather than an FcRn or MHC homolog. FcRn and FcRY both exhibit ligand binding at the acidic pH of endosomes and ligand release at the slightly basic pH of blood. Here we show that FcRY expressed in polarized mammalian epithelial cells functioned in endocytosis, bidirectional transcytosis, and recycling of chicken FcY/IgY. Confocal immunofluorescence studies demonstrated that IgY binding and endocytosis occurred at acidic but not basic pH, mimicking pH-dependent uptake of IgG by FcRn. Colocalization studies showed FcRY-mediated internalization via clathrin-coated pits and transport involving early and recycling endosomes. Disruption of microtubules partially inhibited apical-to-basolateral and basolateral-to-apical transcytosis, but not recycling, suggesting the use of different trafficking machinery. Our results represent the first cell biological evidence of functional equivalence between FcRY and FcRn and provide an intriguing example of how evolution can give rise to systems in which similar biological requirements in different species are satisfied utilizing distinct protein folds
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