4,190 research outputs found

    Comments on the Entanglement Entropy on Fuzzy Spaces

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    We locate the relevant degrees of freedom for the entanglement entropy on some 2+1 fuzzy models. It is found that the entropy is stored in the near boundary degrees of freedom. We give a simple analytical derivation for the area law using 1/N1/N like expansion when only the near boundary degrees of freedom are incorporated. Numerical and qualitative evidences for the validity of near boundary approximation are finally given .Comment: 14 pages, 2 figure

    Breathers and kinks in a simulated crystal experiment

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    We develop a simple 1D model for the scattering of an incoming particle hitting the surface of mica crystal, the transmission of energy through the crystal by a localized mode, and the ejection of atom(s) at the incident or distant face. This is the first attempt to model the experiment described in Russell and Eilbeck in 2007 (EPL, v. 78, 10004). Although very basic, the model shows many interesting features, for example a complicated energy dependent transition between breather modes and a kink mode, and multiple ejections at both incoming and distant surfaces. In addition, the effect of a heavier surface layer is modelled, which can lead to internal reflections of breathers or kinks at the crystal surface.Comment: 15 pages, 12 figures, based on a talk given at the conference "Localized Excitations in Nonlinear Complex Systems (LENCOS)", Sevilla (Spain) July 14-17, 200

    Large-time Behavior of Solutions to the Inflow Problem of Full Compressible Navier-Stokes Equations

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    Large-time behavior of solutions to the inflow problem of full compressible Navier-Stokes equations is investigated on the half line R+=(0,+)R^+ =(0,+\infty). The wave structure which contains four waves: the transonic(or degenerate) boundary layer solution, 1-rarefaction wave, viscous 2-contact wave and 3-rarefaction wave to the inflow problem is described and the asymptotic stability of the superposition of the above four wave patterns to the inflow problem of full compressible Navier-Stokes equations is proven under some smallness conditions. The proof is given by the elementary energy analysis based on the underlying wave structure. The main points in the proof are the degeneracies of the transonic boundary layer solution and the wave interactions in the superposition wave.Comment: 27 page

    Some comments on the universal constant in DSR

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    Deformed Special Relativity is usually presented as a deformation of Special Relativity accommodating a new universal constant, the Planck mass, while respecting the relativity principle. In order to avoid some fundamental problems (e.g. soccer ball problem), we argue that we should switch point of view and consider instead the Newton constant GG as the universal constant.Comment: 12 pages, Proceedings of DICE2006 (Piombino, Italy

    A Conditional Flow Variational Autoencoder for Controllable Synthesis of Virtual Populations of Anatomy

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    The generation of virtual populations (VPs) of anatomy is essential for conducting in silico trials of medical devices. Typically, the generated VP should capture sufficient variability while remaining plausible and should reflect the specific characteristics and demographics of the patients observed in real populations. In several applications, it is desirable to synthesise virtual populations in a \textit{controlled} manner, where relevant covariates are used to conditionally synthesise virtual populations that fit a specific target population/characteristics. We propose to equip a conditional variational autoencoder (cVAE) with normalising flows to boost the flexibility and complexity of the approximate posterior learnt, leading to enhanced flexibility for controllable synthesis of VPs of anatomical structures. We demonstrate the performance of our conditional flow VAE using a data set of cardiac left ventricles acquired from 2360 patients, with associated demographic information and clinical measurements (used as covariates/conditional information). The results obtained indicate the superiority of the proposed method for conditional synthesis of virtual populations of cardiac left ventricles relative to a cVAE. Conditional synthesis performance was evaluated in terms of generalisation and specificity errors and in terms of the ability to preserve clinically relevant biomarkers in synthesised VPs, that is, the left ventricular blood pool and myocardial volume, relative to the real observed population.Comment: Accepted at MICCAI 202

    More Frequent, Intense, and Extensive Rainfall Events in a Strongly Warming Arctic

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    The changes in the Arctic precipitation profoundly impact the surface mass balance of ice sheet and sea ice, the extent of snow cover, as well as the land/ice surface runoff in the Arctic, particularly when it occurs in liquid form. Here, we use state-of-the-art models from the Coupled Model Intercomparison Project Phase 5 to project the number of days with rainfall, the intensities and onset dates of rainfall events in the Arctic under the strong emission scenario (RCP8.5). The multi-model mean shows that rainfall will occur more frequently in the Arctic at the end of this century (2091-2100), with larger increase in the rainy days over the Pacific and Atlantic sectors (up to 12 days/month) during the cold seasons (October-May) and over the Arctic Ocean (up to 14 days/month) during the warm seasons (June-September) as compared with the present day (2006-2015). Greater uncertainty is found in the cold seasons, which mainly comes from the high variability among different models in the Norwegian Sea. Sixty-seven to ninety-three percentage of the increases in rainy days is contributed by the local warming and the remainder by the increase in total precipitation. Moreover, at the end of this century, the rainfall in spring will occur much earlier than the present day by more than 1 month, and the extent of rainfall will further expand toward the center of the Arctic Ocean and the inland Greenland in the future. The changes of rainfall intensity on the Arctic land area to the climate warming are more sensitive than that on the Arctic Ocean in warm seasons (May-September). The rainfall will be further strengthened in most of the Arctic continents in summer, with the largest increase in the intensity of similar to 2 mm/day along the southwest coast of Greenland. The above results are confirmed by the latest projections from CMIP6 models

    An Assessment of Ammonia Emissions from Dairy Facilities in Pennsylvania

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    A survey of 715 Holstein dairy farms in Pennsylvania was used to construct demographics for the average Holstein dairy farm. The average Holstein dairy farm was composed of 69 lactating cows; 11 nonlactating, pregnant cows; 44 heifers; and 18 calves. Milk production averaged 27.3 kg (60.0 lb). Crop area averaged 73.6 ha. Milk production, crop area and type, average county yields, and herd animal groups were used to construct a typical feeding program for these farms. Typical rations were constructed for six feeding groups (three milk production groups, one nonlactating group, two heifer groups) to meet milk production, pregnancy, and growth requirements. Rations were constructed based on three forage qualities (excellent, average, and poor) typically observed on Pennsylvania dairy farms. Data for animal description (milk production, body weight, growth, and pregnancy status) and ration components and amounts consumed for each animal group were input into the excretion model of the Dairy Nutrient Planner computer program (DNP). Excretion of fecal N and dry matter (DM), urinary N, and total P and K were produced for each animal group and used to assess potential volatile losses of N. Work at the Marshak Dairy, New Bolton Center, indicates the majority of urinary N is rapidly lost as ammonia from dairy facilities. Based on this observation, the losses of N as ammonia were estimated to be 4.63, 4.62, and 4.28 tonne/year for the farm with excellent, average, and poor quality forages, respectively. Volatile losses of N may be reduced most by controlling levels of urea in urine. Urinary N may be reduced through dietary manipulation of protein and carbohydrate sources. Conversion of urea to ammonia may be reduced by altering the pH of barn floors and gutters. Entrapment of ammonia may be accomplished by acidification of manure slurry. Atmospheric ammonia contributes to acid rain, eutrophication of estuaries and lakes, and particulate air pollution. Reduction of ammonia emissions from dairy barns can significantly reduce atmospheric pollution and improve air and water quality
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