367 research outputs found

    Integrated Infrastructure Modelling — Managing Interdependencies with a Generic Approach

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    Infrastructure provision is a highly challenging task, especially when accounting for climate change mitigation and adaptation needs. Efforts of making infrastructure more efficient and flexible result in an increasing number of sensitive infrastructure interdependencies. This enforces an integrated infrastructure assessment for planning purposes, in contrast to the traditional independent infrastructure-sector modelling. For the unification of the existing infrastructure-sector models, we propose the implementation of a generic communication interface, which allows the separate sector-models to communicate at the necessarily disaggregate level in order to account for interdependencies appropriately. This approach allows for infrastructure provision modelling under one unified umbrella in a minimally invasive way, while conserving crucial individualities of the separate models. This is achieved through a generic network description, in which we solve the resource allocation through a pragmatic network-flow algorithm that resembles market and consumer behaviour. The developed framework establishes the basis for fully integrated infrastructure evaluation and hence cross-sectorial infrastructure investment decision making — a crucial tool in times of tight governmental budgets

    The monoid of queue actions

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    We investigate the monoid of transformations that are induced by sequences of writing to and reading from a queue storage. We describe this monoid by means of a confluent and terminating semi-Thue system and study some of its basic algebraic properties, e.g., conjugacy. Moreover, we show that while several properties concerning its rational subsets are undecidable, their uniform membership problem is NL-complete. Furthermore, we present an algebraic characterization of this monoid's recognizable subsets. Finally, we prove that it is not Thurston-automatic

    Critical current degradation in HTS wires due to cyclic mechanical strain

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    HTS wires, which may be used in many devices such as magnets and rotating machines, may be subjected to mechanical strains from electromagnetic, thermal and centripetal forces. In some applications these strains will be repeated several thousand times during the lifetime of the device. We have measured critical current degradation due to repeated strain cycles for both compressive and tensile strains. Results for BSCCO-2223 HTS conductor samples are presented for strain values up to 0.5% and cycle numbers up to and beyond 10/sup 4/

    Quasivariational solutions for first order quasilinear equations with gradient constraint

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    We prove the existence of solutions for an evolution quasi-variational inequality with a first order quasilinear operator and a variable convex set, which is characterized by a constraint on the absolute value of the gradient that depends on the solution itself. The only required assumption on the nonlinearity of this constraint is its continuity and positivity. The method relies on an appropriate parabolic regularization and suitable {\em a priori} estimates. We obtain also the existence of stationary solutions, by studying the asymptotic behaviour in time. In the variational case, corresponding to a constraint independent of the solution, we also give uniqueness results

    Effect of Sarcopenia on the Increase in Liver Volume and Function After Portal Vein Embolization

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    Purpose: Sarcopenia is associated with a decreased kinetic growth rate (KGR) of the future liver remnant (FLR) after portal vein embolization (PVE). However, little is known on the increase in FLR function (FLRF) after PVE. This study evaluated the effect of sarcopenia on the functional growth rate (FGR) after PVE measured with hepatobiliary scintigraphy (HBS). Methods: All patients who underwent PVE at the Amsterdam UMC between January 2005 and August 2017 were analyzed. Functional imaging by HBS was used to determine FGR. Liver volumetry was performed using multiphase contrast computed tomography (CT). Muscle area measurement to determine sarcopenia was taken at the third lumbar level (L3). Results: Out of the 95 included patients, 9 were excluded due to unavailable data. 70/86 (81%) patients were sarcopenic. In the multivariate logistic regression analysis, sarcopenia (p = 0.009) and FLR volume (FRLV) before PVE (p = 0.021) were the only factors correlated with KGR, while no correlation was found with FGR. 90-day mortality was similar across the sarcopenic and non-sarcopenic group (4/53 [8%] versus 1/11 [9%]; p = 1.000). The resection rates were also comparable (53/70 [75%] versus 11/16 [69%]; p = 0.542). Conclusion: FGR after PVE as measured by HBS appears to be preserved in sarcopenic patients. This is in contrast to KGR after PVE as measured by liver volumetry which is decreased in sarcopenic patients. Level of Evidence: Level 3b, cohort and case control studies.</p

    Effect of Sarcopenia on the Increase in Liver Volume and Function After Portal Vein Embolization

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    Purpose: Sarcopenia is associated with a decreased kinetic growth rate (KGR) of the future liver remnant (FLR) after portal vein embolization (PVE). However, little is known on the increase in FLR function (FLRF) after PVE. This study evaluated the effect of sarcopenia on the functional growth rate (FGR) after PVE measured with hepatobiliary scintigraphy (HBS). Methods: All patients who underwent PVE at the Amsterdam UMC between January 2005 and August 2017 were analyzed. Functional imaging by HBS was used to determine FGR. Liver volumetry was performed using multiphase contrast computed tomography (CT). Muscle area measurement to determine sarcopenia was taken at the third lumbar level (L3). Results: Out of the 95 included patients, 9 were excluded due to unavailable data. 70/86 (81%) patients were sarcopenic. In the multivariate logistic regression analysis, sarcopenia (p = 0.009) and FLR volume (FRLV) before PVE (p = 0.021) were the only factors correlated with KGR, while no correlation was found with FGR. 90-day mortality was similar across the sarcopenic and non-sarcopenic group (4/53 [8%] versus 1/11 [9%]; p = 1.000). The resection rates were also comparable (53/70 [75%] versus 11/16 [69%]; p = 0.542). Conclusion: FGR after PVE as measured by HBS appears to be preserved in sarcopenic patients. This is in contrast to KGR after PVE as measured by liver volumetry which is decreased in sarcopenic patients. Level of Evidence: Level 3b, cohort and case control studies.</p

    The Relationship between Antimicrobial Use and Antimicrobial Resistance in Europe

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    In Europe, antimicrobial resistance has been monitored since 1998 by the European Antimicrobial Resistance Surveillance System (EARSS). We examined the relationship between penicillin nonsusceptibility of invasive isolates of Streptococcus pneumoniae (an indicator organism) and antibiotic sales. Information was collected on 1998-99 resistance data for invasive isolates of S. pneumoniae to penicillin, based on surveillance data from EARSS and on outpatient sales during 1997 for beta-lactam antibiotics and macrolides. Our results show that in Europe antimicrobial resistance is correlated with use of beta-lactam antibiotics and macrolides

    High density lipoproteins mediate in vivo protection against staphylococcal phenol-soluble modulins

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    Staphylococcus aureus virulence has been associated with the production of phenol-soluble modulins (PSMs). These PSMs have distinct virulence functions and are known to activate, attract and lyse neutrophils. These PSM-associated biological functions are inhibited by lipoproteins in vitro. We set out to address whether lipoproteins neutralize staphylococcal PSM-associated virulence in experimental animal models. Serum from both LCAT an ABCA1 knockout mice strains which are characterised by near absence of high-density lipoprotein (HDL) levels, was shown to fail to protect against PSM-induced neutrophil activation and lysis in vitro. Importantly, PSM-induced peritonitis in LCAT-/- mice resulted in increased lysis of resident peritoneal macrophages and enhanced neutrophil recruitment into the peritoneal cavity. Notably, LCAT-/- mice were more likely to succumb to staphylococcal bloodstream infections in a PSM-dependent manner. Plasma from homozygous carriers of ABCA1 variants characterized by very low HDL-cholesterol levels, was found to be less protective against PSM-mediated biological functions compared to healthy humans. Therefore, we conclude that lipoproteins present in blood can protect against staphylococcal PSMs, the key virulence factor of community-associated methicillin resistant S. aureus.Biopharmaceutic
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