1,359 research outputs found

    Influence of random roughness on cantilever curvature sensitivity

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    In this work we explore the influence of random surface roughness on the cantilever sensitivity to respond to curvature changes induced by changes in surface stress. The roughness is characterized by the out-of-plane roughness amplitude w, the lateral correlation length x, and the roughness or Hurst exponent H (0<H<1). The cantilever sensitivity is found to decrease with increasing roughness (decreasing H and/or increasing ratio w/x) or equivalently increasing local surface slope. Finally, analytic expressions of the cantilever sensitivity as a function of the parameters w, x, and H are derived in order to allow direct implementation in sensing systems.Comment: 10 pages, 3 figure

    The story of Oh: the aesthetics and rhetoric of a common vowel sound

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    Studies in Musical Theatre is the only peer-reviewed journal dedicated to musical theatre. It was launched in 2007 and is now in its seventh volume. It has an extensive international readership and is edited by Dominic Symonds and George Burrows. This article investigates the use of the ‘word’ ‘Oh’ in a variety of different performance idioms. Despite its lack of ‘meaning’, the sound is used in both conversation and poetic discourse, and I discuss how it operates communicatively and expressively through contextual resonances, aesthetic manipulation and rhetorical signification. The article first considers the aesthetically modernist work of Cathy Berberian in Bussotti’s La Passion Selon Sade; then it considers the rhetorically inflected use of ‘Oh’ to construct social resonance in popular song;finally, it discusses two important uses of the sound ‘Oh’ which bookend the Broadway musical Oklahoma!, serving to consolidate the allegorical and musico-dramatic narrative of the show

    Cluster evolution in a cold Ising ferromagnet:Disappearance of magic numbers with temperature rise

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    Decay and growth of clusters at low and intermediate temperatures based on the two-dimensional square-lattice Ising model has been studied with Monte Carlo simulations employing Glauber (or Metropolis) dynamics, exploiting a procedure where the starting configuration is a cluster (that tend to grow in the applied magnetic field) on a relatively small lattice. The behavior of such a cluster is stochastic and only when typical several thousands of identical clusters are analyzed will the underlying deterministic behavior become apparent. At 0.4Tc, the time-dependent cluster size distribution is relatively broad, but smooth, i.e., Gaussian, and the decay and growth behaviors of various relative compact clusters are compared. At lower temperatures, modulations in the size distribution occur with minima at magic sizes corresponding to n=m×m+1 and n=m×(m+1)+1 with m integer values. A quantitative analysis of the amplitude of the modulations as a function of temperature is performed. Also the relation between the distributions of size and of the number of internal cluster bonds (or cluster perimeter) is scrutinized.

    Arrow update logic

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    We present Arrow Update Logic, a theory of epistemic access elimination that can be used to reason about multi-agent belief change. While the belief-changing "arrow updates" of Arrow Update Logic can be transformed into equivalent belief-changing "action models" from the popular Dynamic Epistemic Logic approach, we prove that arrow updates are sometimes exponentially more succinct than action models. Further, since many examples of belief change are naturally thought of from Arrow Update Logic's perspective of eliminating access to epistemic possibilities, Arrow Update Logic is a valuable addition to the repertoire of logics of information change. In addition to proving basic results about Arrow Update Logic, we introduce a new notion of common knowledge that generalizes both ordinary common knowledge and the "relativized" common knowledge familiar from the Dynamic Epistemic Logic literature

    Copper cable theft: revisiting the price–theft hypothesis

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    Objectives: To test the commonly espoused but little examined hypothesis that fluctuations in the price of metal are associated with changes in the volume of metal theft. Specifically, we analyze the relationship between the price of copper and the number of police recorded 'live’ copper cable thefts from the British railway network (2006 to 2012)

    Cheryl's Birthday

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    We present four logic puzzles and after that their solutions. Joseph Yeo designed 'Cheryl's Birthday'. Mike Hartley came up with a novel solution for 'One Hundred Prisoners and a Light Bulb'. Jonathan Welton designed 'A Blind Guess' and 'Abby's Birthday'. Hans van Ditmarsch and Barteld Kooi authored the puzzlebook 'One Hundred Prisoners and a Light Bulb' that contains other knowledge puzzles, and that can also be found on the webpage http://personal.us.es/hvd/lightbulb.html dedicated to the book.Comment: In Proceedings TARK 2017, arXiv:1707.0825

    Modelling Holling type II functional response in deterministic and stochastic food chain models with mass conservation

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    The Rosenzweig-MacArthur predator-prey model is the building block in modeling food chain, food webs and ecosystems. There are a number of hidden assumptions involved in the derivation. For instance the prey population growth is logistic without predation but also with predation. In order to reveal these we will start with modelling a resource-predator-prey system in a closed spatially homogeneous environment. This allows us to keep track of the nutrient flow. With an instantaneous remineralisation of the products excreted in the environment by the populations and dead body mass there is conservation of mass. This allows for a model dimension reduction and yields the mass balance predator-prey model. When furthermore the searching and handling processes are much faster that the population changing rates, the trophic interaction is described by a Holling type II functional response, also assumed in the Rosenzweig-MacArthur model. The derivation uses an extended deterministic model with number of searching and handling predators as model variables where the ratio of the predator/prey body masses is used as a mechanistic time-scale parameter. This extended model is also used as a starting point for the derivation of a stochastic model. We will investigate the stochastic effects of random switching between searching and handling of the predators and predator dying. Prey growth by consumption of ambient resources is still deterministic and therefore the stochastic model is hybrid. The transient dynamics is studied by numerical Monte Carlo simulations and also the quasi-equilibrium distribution for the population quantities is calculated. The body mass of the prey individual is the scaling parameter in the stochastic model formulation. This allows for a quantification of the mean-field approximation criterion for the justification of replacement of the stochastic by a deterministic model.Marie Skłodowska-Curie grant agreement No. 79249

    Polarization retention loss in PbTiO3 ferroelectric films due to leakage currents

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    The relationship between retention loss in single crystal PbTiO3 ferroelectric thin films and leakage currents is demonstrated by piezoresponse and conductive atomic force microscopy measurements. It was found that the polarization reversal in the absence of an electric field followed a stretched exponential behavior 1−exp[−(t/k)^d] with exponent d>1, which is distinct from a dispersive random walk process with d<1. The latter has been observed in polycrystalline films for which retention loss was associated with grain boundaries. The leakage current indicates power law scaling at short length scales, which strongly depends on the applied electric field. Additional information of the microstructure, which contributes to an explanation of the presence of leakage currents, is presented with high resolution transmission electron microscopy analysis.

    Mitochondrial Function and Diabetes: Consequences for Skeletal and Cardiac Muscle Metabolism

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    SIGNIFICANCE: An early hallmark in the development of type 2 diabetes is the resistance to the effect of insulin in skeletal muscle and in the heart. Since mitochondrial function was found to be diminished in patients with type 2 diabetes, it was suggested that this defect might be involved in the etiology of insulin resistance. Although several hypotheses were suggested, yet unclear is the mechanistic link between these two phenomena. Recent advances: Herein, we review the evidence for disturbances in mitochondrial function in skeletal muscle and the heart in the diabetic state. Also the mechanisms involved in improving mitochondrial function are considered and, whenever possible, human data is cited. Reported evidence shows that interventions that improve skeletal muscle mitochondrial function also improve insulin sensitivity in humans. In the heart, available data from animal studies suggests that enhancement of mitochondrial function can reverse aging-induced changes in heart function, and can be protective against cardiomyopathy and heart failure. FUTURE DIRECTIONS: Mitochondria and their functions can be targeted with the aim of improving skeletal muscle insulin sensitivity and cardiac function. However, human clinical intervention studies are needed to fully substantiate the potential of mitochondria as a target to prevent cardiometabolic disease
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