901 research outputs found

    Testing the robustness of optimal operating plans under various future hydro-climatic scenarios

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    A key challenge for water resources planning processes around the world is to develop operating plans that are optimal under a range of hydro-climatic conditions. The consequences of such long term planning decisions can vary in terms of the social, economic, and environmental impacts. Given these potential impacts, it is important that operating plans are tested under a range of hydro-climatic conditions to ensure that they are sufficiently robust to withstand future changes in climate. The aim of this study is to present a procedure for testing the robustness of optimal operating plans for complex water resources systems using a combined multi-objective optimisation and sustainability assessment approach. The approach embeds an optimisation-simulation (O-S) model which is applied to an 18-objective function multi-objective optimisation problem of the Wimmera-Mallee Water Supply System (WMWSS). The WMWSS is a multi-reservoir system located in Western Victoria (Australia) which is operated to meet a range of competing interests for water using complex operating rules. The O-S model is applied to the WMWSS to search for optimal operating plans over a 100-year period into the future assuming two plausible greenhouse gas (GHG) emission levels. The two GHG emission scenarios represent lower and higher ends of the estimated range of projected GHG emissions, providing a wide range of future hydro-climatic conditions. A robustness test is used to evaluate the validity of the most sustainable optimal operating plans under the two GHG emmission scenarios and also those found previously under a historic hydro-climatic sequence. The test results show that the status quo or base case operating plan is optimal but is neither the highest nor the lowest in terms of the level of sustainability that could be achieved in the WMWSS, under historic and the higher GHG emission scenario. Moreover, the results show that the most sustainable optimal operating plans found under the three hydro-climatic scenarios are sufficiently robust to withstand the full range of hydro-climatic conditions considered whereas the base case operating plan is not as robust. The risks involved in the implementation of operating plans which exhibit large deviations from the base case operating plan are discussed. These risks highlight the importance of problem formulation and sensitivity analysis of the optimal operating plans in order to find real world solutions to real world problems. © CURRAN-CONFERENCE. All rights reserved

    Walter Miles and His 1920 Grand Tour of European Physiology and Psychology Laboratories: A Reproduction of the Original Typescript

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    Walter R. Miles (1885-1978) was an American experimental psychologist very much interested in laboratory apparatus and procedures and their applications to human behavior. Early in his career, Miles received an appointment as a research scientist at the Carnegie Nutrition Laboratory in Boston, Massachusetts. When Miles arrived at the Carnegie Nutrition Laboratory in 1914, work was well underway on the physiological effects of various nutrients on the human body. Miles began studies on the effects of alcohol on physiological and psychological functioning. The First World War severed many of the relationships that the Carnegie Laboratory had with research counterparts in Europe. After the war, efforts were made to reestablish these ties. From April through August of 1920, Miles visited 57 laboratories and institutes in 9 different countries throughout Europe. A fastidious observer and note taker, Miles documented his journey in exquisite detail. At every stop, he observed, recorded, and interacted with key figures in European physiology and psychology. He gathered all this information together into a highly-detailed report of more than 300 pages. The report, part of the Walter Miles Papers available at the Archives of the History of American Psychology at the University of Akron, was never formally published. Now available in print, this title provides unique information about the workings of major centers of physiological and psychological research in early 20th century Europe. The book is introduced by C. James Goodwin, a renowned Miles\u27 scholar.https://ideaexchange.uakron.edu/uapress_publications/1137/thumbnail.jp

    Substrate Binding Regulates Redox Signaling in Human DNA Primase

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    Generation of daughter strands during DNA replication requires the action of DNA primase to synthesize an initial short RNA primer on the single-stranded DNA template. Primase is a heterodimeric enzyme containing two domains whose activity must be coordinated during primer synthesis: an RNA polymerase domain in the small subunit (p48) and a [4Fe4S] cluster-containing C-terminal domain of the large subunit (p58C). Here we examine the redox switching properties of the [4Fe4S] cluster in the full p48/p58 heterodimer using DNA electrochemistry. Unlike with isolated p58C, robust redox signaling in the primase heterodimer requires binding of both DNA and NTPs; NTP binding shifts the p48/p58 cluster redox potential into the physiological range, generating a signal near 160 mV vs NHE. Preloading of primase with NTPs enhances catalytic activity on primed DNA, suggesting that primase configurations promoting activity are more highly populated in the NTP-bound protein. We propose that p48/p58 binding of anionic DNA and NTPs affects the redox properties of the [4Fe4S] cluster; this electrostatic change is likely influenced by the alignment of primase subunits during activity because the configuration affects the [4Fe4S] cluster environment and coupling to DNA bases for redox signaling. Thus, both binding of polyanionic substrates and configurational dynamics appear to influence [4Fe4S] redox signaling properties. These results suggest that these factors should be considered generally in characterizing signaling networks of large, multisubunit DNA-processing [4Fe4S] enzymes

    Best practice in the use of peripheral venous catheters: A scoping review and expert consensus

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    Background: Peripheral intravenous catheters (PIVCs) are the most commonly used invasive medical device in health care with an overall failure rate of 35e50%. Most complications are non-infectious, but local site and bloodstream infections can also occur. Even if PIVC-related infections are rare, the total number of affected patients and the preponderance of Staphylococcus aureus as related pathogen due to the frequent use of these devices are relevant arguments to implement preventive strategies. The aim of this document is to raise awareness that infections caused by PIVCs are a relevant problem that can be reduced by practice change. Methods: A panel of experts discussed this topic based on evidence and proposed practice points by consensus.Discussion: Despite published evidence-based guidelines, current practice concerning aseptic techniques during insertion and care of PIVCs often are substandard. These devices have become commonplace and tend to be perceived as safe. An overall lack of awareness about the true risks associated with the use of PIVCs results in limited surveillance and prevention efforts.Conclusion: Successful insertion and maintenance bundles in central venous lines are a blueprint to the implementation of adapted bundle strategies in the prevention of PIVCassociated infections. There is a need for studies to specifically investigate infection prevention in PIVCs and to agree on effective and implementable bundles.& COPY; 2023 The Authors. Published by Elsevier Ltd on behalf of The Healthcare Infection Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

    Best practice in the use of peripheral venous catheters: A scoping review and expert consensus

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    BACKGROUND Peripheral intravenous catheters (PIVCs) are the most commonly used invasive medical device in health care with an overall failure rate of 35-50%. Most complications are non-infectious, but local site and bloodstream infections can also occur. Even if PIVC-related infections are rare, the total number of affected patients and the preponderance of Staphylococcus aureus as related pathogen due to the frequent use of these devices are relevant arguments to implement preventive strategies. The aim of this document is to raise awareness that infections caused by PIVCs are a relevant problem that can be reduced by practice change. METHODS A panel of experts discussed this topic based on evidence and proposed practice points by consensus. DISCUSSION Despite published evidence-based guidelines, current practice concerning aseptic techniques during insertion and care of PIVCs often are substandard. These devices have become commonplace and tend to be perceived as safe. An overall lack of awareness about the true risks associated with the use of PIVCs results in limited surveillance and prevention efforts. CONCLUSION Successful insertion and maintenance bundles in central venous lines are a blueprint to the implementation of adapted bundle strategies in the prevention of PIVC-associated infections. There is a need for studies to specifically investigate infection prevention in PIVCs and to agree on effective and implementable bundles

    A unified hyperbolic formulation for viscous fluids and elastoplastic solids

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    We discuss a unified flow theory which in a single system of hyperbolic partial differential equations (PDEs) can describe the two main branches of continuum mechanics, fluid dynamics, and solid dynamics. The fundamental difference from the classical continuum models, such as the Navier-Stokes for example, is that the finite length scale of the continuum particles is not ignored but kept in the model in order to semi-explicitly describe the essence of any flows, that is the process of continuum particles rearrangements. To allow the continuum particle rearrangements, we admit the deformability of particle which is described by the distortion field. The ability of media to flow is characterized by the strain dissipation time which is a characteristic time necessary for a continuum particle to rearrange with one of its neighboring particles. It is shown that the continuum particle length scale is intimately connected with the dissipation time. The governing equations are represented by a system of first order hyperbolic PDEs with source terms modeling the dissipation due to particle rearrangements. Numerical examples justifying the reliability of the proposed approach are demonstrated.Comment: 6 figure

    Probing the Coevolution of Supermassive Black Holes and Quasar Host Galaxies

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    At low redshift, there are fundamental correlations between the mass of supermassive black holes (MBH) and the mass (Mbulge) and luminosity of the host galaxy bulge. We investigate the same relation at z>=1. Using virial mass estimates for 11 quasars at z >~2 to measure their black hole mass, we find that black holes at high z fall nearly on the same MBH versus R-band magnitude (MR) relation (to ~0.3 mag) as low-redshift active and inactive galaxies, without making any correction for luminosity evolution. Using a set of conservative assumptions about the host galaxy stellar population, we show that at z>~2 (10 Gyrs ago) the ratio of MBH/Mbulge was 3--6 times larger than today. Barring unknown systematic errors on the measurement of MBH, we also rule out scenarios in which moderately luminous quasar hosts at z>~2 were fully formed bulges that passively fade to the present epoch. On the other hand, 5 quasar hosts at z~1 are consistent with current day MBH-MR relationship after taking into account evolution, appropriate for that of E/S0 galaxies. Therefore, z~1 host galaxies appear to fit the hypothesis they are fully formed early-type galaxies. We also find that most quasar hosts with absolute magnitudes brighter than MR = -23 cannot fade below L* galaxies today, regardless of their stellar population makeup, because their black hole masses are too high and they must arrive at the local MBH-MR relationship by z=0.Comment: 16 pages, 3 figures, 2 tables. ApJ in press. Corrected for minor typographical error

    Light propagation in non-trivial QED vacua

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    Within the framework of effective action QED, we derive the light cone condition for homogeneous non-trivial QED vacua in the geometric optics approximation. Our result generalizes the ``unified formula'' suggested by Latorre, Pascual and Tarrach and allows for the calculation of velocity shifts and refractive indices for soft photons travelling through these vacua. Furthermore, we clarify the connection between the light velocity shift and the scale anomaly. This study motivates the introduction of a so-called effective action charge that characterizes the velocity modifying properties of the vacuum. Several applications are given concerning vacuum modifications caused by, e.g., strong fields, Casimir systems and high temperature.Comment: 13 pages, REVTeX, 3 figures, to appear in Phys. Rev.
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