1,708 research outputs found

    Comment on "Freezing by heating in a driven mesoscopic system"

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    We point out that the phenomenon ``heating by freezing'' discovered in nonequilibrium simulations by Helbing, et al. (PRL 84, 1240 (2000)) extends to equilibrium systems as well. We argue that such reentrant fluctuation-driven freezing can, for example, be realized in two-dimensional colloidal systems subjected to a one-dimensional periodic potential.Comment: 4 RevTeX pg

    An Empirical Investigation of a General System Development Model

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    Experimental demonstration of a light-ray-direction-flipping METATOY based on confocal lenticular arrays

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    We show, theoretically and experimentally, that a sheet formed by two confocal lenticular arrays can flip one component of the local light-ray direction. Ray-optically, such a sheet is equivalent to a Dove-prism sheet, an example of a METATOY (metamaterial for light rays), a structure that changes the direction of transmitted light rays in a way that cannot be performed perfectly wave-optically.Comment: 5 pages, 6 figure

    Theoretical Behavior of XAI Methods in the Presence of Suppressor Variables

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    In recent years, the community of 'explainable artificial intelligence' (XAI) has created a vast body of methods to bridge a perceived gap between model 'complexity' and 'interpretability'. However, a concrete problem to be solved by XAI methods has not yet been formally stated. As a result, XAI methods are lacking theoretical and empirical evidence for the 'correctness' of their explanations, limiting their potential use for quality-control and transparency purposes. At the same time, Haufe et al. (2014) showed, using simple toy examples, that even standard interpretations of linear models can be highly misleading. Specifically, high importance may be attributed to so-called suppressor variables lacking any statistical relation to the prediction target. This behavior has been confirmed empirically for a large array of XAI methods in Wilming et al. (2022). Here, we go one step further by deriving analytical expressions for the behavior of a variety of popular XAI methods on a simple two-dimensional binary classification problem involving Gaussian class-conditional distributions. We show that the majority of the studied approaches will attribute non-zero importance to a non-class-related suppressor feature in the presence of correlated noise. This poses important limitations on the interpretations and conclusions that the outputs of these XAI methods can afford.Comment: Accepted at ICML 202

    Swanee River Moon / words by H Pitman Clark

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    Cover: moon trees and the river; Publisher: Leo Feist Inc. (New York)https://egrove.olemiss.edu/sharris_d/1029/thumbnail.jp

    Method of producing ceramic distribution members for solid state electrolyte cells

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    A solid state electrolyte cells apparatus and method of producing is disclosed. The apparatus can be used for separating oxygen from an oxygen-containing feedstock or as a fuel cell for reacting fluids. Cells can be stacked so that fluids can be introduced and removed from the apparatus through ceramic distribution members having ports designed for distributing the fluids in parallel flow to and from each cell. The distribution members can also serve as electrodes to membranes or as membrane members between electrodes, The distribution member design does not contain any horizontal internal ports which allows the member to be thin. A method of tape casting in combination with an embossing method allows intricate radial ribs and bosses to be formed on each distribution member. The bosses serve as seals for the ports and allow the distribution members to be made without any horizontal internal ports

    Ceramic distribution members for solid state electrolyte cells and method of producing

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    A solid state electrolyte cells apparatus and method of producing is disclosed. The apparatus can be used for separating oxygen from an oxygen-containing feedstock or as a fuel cell for reacting fluids. Cells can be stacked so that fluids can be introduced and removed from the apparatus through ceramic distribution members having ports designed for distributing the fluids in parallel flow to and from each cell. The distribution members can also serve as electrodes to membranes or as membrane members between electrodes. The distribution member design does not contain any horizontal internal ports which allows the member to be thin. A method of tape casting in combination with an embossing method allows intricate radial ribs and bosses to be formed on each distribution member. The bosses serve as seals for the ports and allow the distribution members to be made without any horizontal internal ports

    Phonon resonances in atomic currents through Bose-Fermi mixtures in optical lattices

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    We present an analysis of Bose-Fermi mixtures in optical lattices for the case where the lattice potential of the fermions is tilted and the bosons (in the superfluid phase) are described by Bogoliubov phonons. It is shown that the Bogoliubov phonons enable hopping transitions between fermionic Wannier-Stark states; these transitions are accompanied by energy dissipation into the superfluid and result in a net atomic current along the lattice. We derive a general expression for the drift velocity of the fermions and find that the dependence of the atomic current on the lattice tilt exhibits negative differential conductance and phonon resonances. Numerical simulations of the full dynamics of the system based on the time-evolving block decimation algorithm reveal that the phonon resonances should be observable under the conditions of a realistic measuring procedure.Comment: 8 pages, 5 figure

    Endoscopic ultrasound-guided celiac plexus neurolysis (EUS-CPN) technique and analgesic efficacy in patients with pancreatic cancer: A systematic review and meta-analysis

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    Background: Endoscopic Ultrasound-guided Celiac Plexus Neurolysis (EUS-CPN) for the treatment of abdominal pain in pancreatic cancer can be administered in three different ways, depending on the site of needle insertion: central injection (CI), bilateral injection (BI) and celiac ganglia neurolysis (CGN). This meta-analysis aimed to (1) estimate the overall efficacy of the EUS-CPN; (2) compare the efficacy of each of the three techniques; and (3) investigate demographic and disease characteristics as potential predictors of treatment response. Methods: We searched MEDLINE and EMBASE for studies that reported the proportion of treatment responders to EUS-CPN overall, and according to the technique used. We performed a random effects meta-analysis of proportions, and meta-regression was used to estimate the association between technique and clinical characteristics on treatment response. The safety profile was reviewed through narrative synthesis. Results: Overall response rate to EUS-CPN was 68% (95% CI 61%–74%) at week two and 53% (95% CI 45%–62%) at week four. There was no evidence of a significant difference in the response rates between the three techniques. Demographics and disease characteristics were not associated with treatment response. Serious complications have been reported for BI and CGN but not for CI. Moderate to high risk of bias was observed. Discussion: EUS-CPN is a useful adjunct to opioids in the management of pain. There is no evidence of a difference in the efficacy among the three techniques, however, CI is the only one for which serious complications have not been reported. Future research should focus on the appropriate timing of EUS-CPN (early versus on demand) and randomised comparison to establish the comparative efficacy of each technique
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