1,214 research outputs found

    Diffusion Process in a Flow

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    We establish circumstances under which the dispersion of passive contaminants in a forced, deterministic or random, flow can be consistently interpreted as a Markovian diffusion process. In case of conservative forcing the repulsive case only, F=V\vec{F}=\vec{\nabla }V with V(x,t)V(\vec{x},t) bounded from below, is unquestionably admitted by the compatibility conditions. A class of diffusion processes is exemplified, such that the attractive forcing is allowed as well, due to an appropriate compensation coming from the "pressure" term. The compressible Euler flows form their subclass, when regarded as stochastic processes. We establish circumstances under which the dispersion of passive contaminants in a forced, deterministic or random, flow can be consistently interpreted as a Markovian diffusion process. In case of conservative forcing the repulsive case only, F=V\vec{F}=\vec{\nabla }V with V(x,t)V(\vec{x},t) bounded from below, is unquestionably admitted by the compatibility conditions. A class of diffusion processes is exemplified, such that the attractive forcing is allowed as well, due to an appropriate compensation coming from the "pressure" term. The compressible Euler flows form their subclass, when regarded as stochastic processes.Comment: 10 pages, Late

    Synchronizing inventory and transport within supply chain management

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    The problem considers synchronized optimization of inventory and transport, and focuses on producer-distributor relations. Particular attention is paid to developing a mathematical model and an optimization problem that can be used to minimize the overall distribution cost by an appropriate placement of warehouses and cross-docking points. Solutions to this problem are explored using genetic algorithms and ideas from graph/network theory. Note: there are three separate reports contained within the uploaded .pdf file

    Perturbations of Noise: The origins of Isothermal Flows

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    We make a detailed analysis of both phenomenological and analytic background for the "Brownian recoil principle" hypothesis (Phys. Rev. A 46, (1992), 4634). A corresponding theory of the isothermal Brownian motion of particle ensembles (Smoluchowski diffusion process approximation), gives account of the environmental recoil effects due to locally induced tiny heat flows. By means of local expectation values we elevate the individually negligible phenomena to a non-negligible (accumulated) recoil effect on the ensemble average. The main technical input is a consequent exploitation of the Hamilton-Jacobi equation as a natural substitute for the local momentum conservation law. Together with the continuity equation (alternatively, Fokker-Planck), it forms a closed system of partial differential equations which uniquely determines an associated Markovian diffusion process. The third Newton law in the mean is utilised to generate diffusion-type processes which are either anomalous (enhanced), or generically non-dispersive.Comment: Latex fil

    Burgers' Flows as Markovian Diffusion Processes

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    We analyze the unforced and deterministically forced Burgers equation in the framework of the (diffusive) interpolating dynamics that solves the so-called Schr\"{o}dinger boundary data problem for the random matter transport. This entails an exploration of the consistency conditions that allow to interpret dispersion of passive contaminants in the Burgers flow as a Markovian diffusion process. In general, the usage of a continuity equation tρ=(vρ)\partial_t\rho =-\nabla (\vec{v}\rho), where v=v(x,t)\vec{v}=\vec{v}(\vec{x},t) stands for the Burgers field and ρ\rho is the density of transported matter, is at variance with the explicit diffusion scenario. Under these circumstances, we give a complete characterisation of the diffusive transport that is governed by Burgers velocity fields. The result extends both to the approximate description of the transport driven by an incompressible fluid and to motions in an infinitely compressible medium. Also, in conjunction with the Born statistical postulate in quantum theory, it pertains to the probabilistic (diffusive) counterpart of the Schr\"{o}dinger picture quantum dynamics.Comment: Latex fil

    Ideologies “ORDER – DISORDER” as an object of linguistic research

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     The paper deals with the problems of ideological language use. It also considers an ideologeme as a linguo-cognitive phenomenon. The definition of an ideologeme as a special cognitive unit which gives a specified ideological meaning and emotional content to a fact or an action and has an increased axiological degree, the characteristics of which depend on ideological positions, regulations and party instructions is given. On the basis of the research language material some language factors enabling transformation of usual lexical items into ideologemes are reported to be revealed. The authors also outline some specific features of lexical items “order – disorder” transformation into ideologemes. The conclusion drawn is that namely lexical and grammatical co-occurrence promotes their transformation into ideologemes

    High Bandwidth Synaptic Communication and Frequency Tracking in Human Neocortex

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    Neuronal firing, synaptic transmission, and its plasticity form the building blocks for processing and storage of information in the brain. It is unknown whether adult human synapses are more efficient in transferring information between neurons than rodent synapses. To test this, we recorded from connected pairs of pyramidal neurons in acute brain slices of adult human and mouse temporal cortex and probed the dynamical properties of use-dependent plasticity. We found that human synaptic connections were purely depressing and that they recovered three to four times more swiftly from depression than synapses in rodent neocortex. Thereby, during realistic spike trains, the temporal resolution of synaptic information exchange in human synapses substantially surpasses that in mice. Using information theory, we calculate that information transfer between human pyramidal neurons exceeds that of mouse pyramidal neurons by four to nine times, well into the beta and gamma frequency range. In addition, we found that human principal cells tracked fine temporal features, conveyed in received synaptic inputs, at a wider bandwidth than for rodents. Action potential firing probability was reliably phase-locked to input transients up to 1,000 cycles/s because of a steep onset of action potentials in human pyramidal neurons during spike trains, unlike in rodent neurons. Our data show that, in contrast to the widely held views of limited information transfer in rodent depressing synapses, fast recovering synapses of human neurons can actually transfer substantial amounts of information during spike trains. In addition, human pyramidal neurons are equipped to encode high synaptic information content. Thus, adult human cortical microcircuits relay information at a wider bandwidth than rodent microcircuits

    Environmental Enrichment Preceding Early Adulthood Methylphenidate Treatment Leads to Long Term Increase of Corticosterone and Testosterone in the Rat

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    Attention-deficit/hyperactivity disorder (ADD/ADHD) has been emerging as a world-wide psychiatric disorder. There appears to be an increasing rate of stimulant drug abuse, specifically methylphenidate (MPH) which is the most common treatment for ADHD, among individuals who do not meet the criteria for ADHD and particularly for cognitive enhancement among university students. However, the long term effects of exposure to MPH are unknown. Thus, in light of a developmental approach in humans, we aimed to test the effects of adolescence exposure to enriched environment (EE) followed by MPH administration during early adulthood, on reactions to stress in adulthood. Specifically, at approximate adolescence [post natal days (PND) 30–60] rats were reared in EE and were treated with MPH during early adulthood (PND 60–90). Adult (PND 90–92) rats were exposed to mild stress and starting at PND 110, the behavioral and endocrine effects of the combined drug and environmental conditions were assessed. Following adolescence EE, long term exposure to MPH led to decreased locomotor activity and increased sucrose preference. EE had a beneficial effect on PPI (attentive abilities), which was impaired by long term exposure to MPH. Finally, the interaction between EE and, exposure to MPH led to long-term elevated corticosterone and testosterone levels. In view of the marked increase in MPH consumption over the past decade, vigilance is crucial in order to prevent potential drug abuse and its long term detrimental consequences

    Measurement of D0D0D^0-\overline{D}^0 mixing and search for CPCP violation with D0K+πD^0\rightarrow K^+\pi^- decays

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    A measurement of the time-dependent ratio of the D0K+πD^0\rightarrow K^+\pi^- to D0K+π\overline{D}^0\rightarrow K^+\pi^- decay rates is reported. The analysis uses a sample of proton-proton collisions corresponding to an integrated luminosity of 6 fb1^-1 recorded by the LHCb experiment from 2015 through 2018 at a center-of-mass energy of 13 TeV. The D0D^0 meson is required to originate from a D+D0π+D^{*+}\rightarrow D^0\pi^+ decay, such that its flavor at production is inferred from the charge of the accompanying pion. The measurement is performed simultaneously for the K+πK^+\pi^- and Kπ+K^-\pi^+ final states, allowing both mixing and CPCP-violation parameters to be determined. The value of the ratio of the decay rates at production is determined to be RKπ=(343.1±2.0)×105R_{K\pi} = (343.1 \pm 2.0) \times 10^{-5}. The mixing parameters are measured to be cKπ=(51.4±3.5)×104c_{K\pi} = (51.4 \pm 3.5) \times 10^{-4} and cKπ=(13±4)×106c_{K\pi}^{\prime} = (13 \pm 4) \times 10^{-6}, where RKπcKπ\sqrt{R_{K\pi}}c_{K\pi} is the linear coefficient of the expansion of the ratio as a function of decay time in units of the D0D^0 lifetime, and cKπc_{K\pi}^{\prime} is the quadratic coefficient, both averaged between the K+πK^+\pi^- and Kπ+K^-\pi^+ final states. The precision is improved relative to the previous best measurement by approximately 60%. No evidence for CPCP violation is found.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/Publications/LHCbProjectPublic/LHCb-PAPER-2024-008.htm

    Measurements of the branching fraction ratio B(ϕμ+μ)/B(ϕe+e)\cal{B}(\phi \to \mu^+\mu^-)/\cal{B}(\phi \to e^+e^-) with charm meson decays

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    Measurements of the branching fraction ratio B(ϕμ+μ)/B(ϕe+e){\cal{B}(\phi \to \mu^+ \mu^-)/\cal{B}(\phi\to e^+e^-)} with Ds+π+ϕ{D_{s}^{+} \to \pi^{+} \phi} and D+π+ϕ{D^{+} \to \pi^{+} \phi} decays, denoted RϕπsR^{s}_{\phi \pi} and RϕπdR^{d}_{\phi \pi}, are presented. The analysis is performed using a dataset corresponding to an integrated luminosity of 5.4fb1\,\rm{fb}^{-1} of pppp collision data collected with the LHCb experiment. The branching fractions are normalised with respect to the B+K+J/ψ(e+e){B^{+} \to K^{+} J/\psi(\to e^+e^-)} and B+K+J/ψ(μ+μ){B^{+} \to K^{+} J/\psi(\to \mu^+\mu^-)} decay modes. The combination of the results yields Rϕπ=1.022±0.012(stat)±0.048(syst). R_{\phi \pi} = 1.022 \pm 0.012 \,({\rm stat}) \, \pm 0.048 \,({\rm syst}). The result is compatible with previous measurements of the ϕ+\phi \to \ell^{+}\ell^{-} branching fractions and predictions based on the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-038.html (LHCb public pages

    A measurement of ∆Γs

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    Using a dataset corresponding to 9 fb−1 of integrated luminosity collected with the LHCb detector between 2011 and 2018 in proton-proton collisions, the decay-time distributions of the decay modes Bs 0→J/ψη′ and Bs 0→J/ψπ+π− are studied. The decay-width difference between the light and heavy mass eigenstates of the Bs 0 meson is measured to be ∆Γs = 0.087 ± 0.012 ± 0.009 ps−1, where the first uncertainty is statistical and the second systematic
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