17,157 research outputs found

    Graviton production through photon-quark scattering at the LHC

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    We have investigated real graviton emission in the ADD and RS model of extra dimensions through the photoproduction process pp-> p gamma p-> pGqX at the LHC. We have considered all contributions from the subprocesses gamma q -> G q, where q=u,d,c,s,b,anti-u,anti-d, anti-c, anti-s, anti-b quark. The constraints on model parameters of the ADD and RS model of extra dimensions have been calculated. During numerical calculations we have taken account of 3, 4, 5 and 6 large extra dimensional scenarios. The constraints on RS model parameters have been calculated by considering G -> gamma gamma, e^- e^+, mu^- mu^+ decay channels of the graviton.Comment: 27 pages, 12 figures; final version to appear in PR

    A space-fractional cable equation for the propagation of action potentials in myelinated neurons

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    Myelinated neurons are characterized by the presence of myelin, a multilaminated wrapping around the axons formed by specialized neuroglial cells. Myelin acts as an electrical insulator and therefore, in myelinated neurons, the action potentials do not propagate within the axons but happen only at the nodes of Ranvier which are gaps in the axonal myelination. Recent advancements in brain science have shown that the shapes, timings, and propagation speeds of these so-called saltatory action potentials are controlled by various biochemical interactions among neurons, glial cells, and the extracellular space. Given the complexity of brain's structure and processes, the work hypothesis made in this paper is that non-local effects are involved in the optimal propagation of action potentials. A space-fractional cable equation for the action potentials propagation in myelinated neurons is proposed that involves spatial derivatives of fractional order. The effects of non-locality on the distribution of the membrane potential are investigated using numerical simulations.Comment: 20 pages, 14 figures; added reference, updated formulas, added new formulas, corrected typos, added 4 figure

    A Search for pair production of the LSP ντ~\tilde{\nu_{\tau}} at the CLIC via RPV Decays

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    In this work we consider pair production of LSP tau-sneutrinos at the Compact Lineer Collider. We assume that tau-sneutrinos decays in to e\textmu pair via RPV interactions. Backgroundless subprocess ee+ν~ν~ˉμ+μ+ee(μμe+e+)e{}^{-}e^{+}\rightarrow\tilde{\nu}\bar{\tilde{\nu}}\rightarrow\mu^{+}\mu^{+}e^{-}e^{-}(\mu^{-}\mu^{-}e^{+}e^{+}) is analyzed in details. Achievable limits on Br(ν~τμe)Br\,(\tilde{\nu}_{\tau}\rightarrow\mu e) at 3σ3\sigma and 5σ5\sigma CL are obtained depending on ντ~\tilde{\nu_{\tau}} mass.Comment: 8 pages, 5 figure

    Directional Recurrence for Infinite Measure Preserving Z^d Actions

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    We define directional recurrence for infinite measure preserving Z^d actions both intrinsically and via the unit suspension flow and prove that the two definitions are equivalent. We study the structure of the set of recurrent directions and show it is always a G_delta set. We construct an example of a recurrent action with no recurrent directions, answering a question posed in a 2007 paper of Daniel J. Rudolph. We also show by example that it is possible for a recurrent action to not be recurrent in an irrational direction even if all its sub-actions are recurrent.Comment: Corrections to proof of Proposition 3.3 and other minor edits to assist with readibility. Version to appear in ETD

    The relative effects of crude oil price and exchange rate on petroleum product prices: Evidence from a set of Northern Meditteranean countries

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    Cataloged from PDF version of article.This paper provides a set of empirical evidence from five Northern Mediterranean countries that are subject to similar refinery reference prices regarding the relative sensitivity of crude oil prices and exchange rate on (pre-tax) petroleum product prices. The empirical evidence reveals that a one percent increase in exchange rate (depreciation) increases petroleum product prices less than a one percent increase in crude oil prices does in the long run. In the short run, however, a one percent increase in exchange rate increases petroleum product prices more than a one percent increase in crude oil prices does. © 2014 Elsevier B.V. All rights reserved

    The effect of vascular graft and human umbilical cord blood-derived CD34+ stem cell on peripheral nerve healing

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    AIM: There are many trials concerning peripheral nerve damage causes and treatment options. Unfortunately, nerve damage is still a major problem regarding health, social and economic issues. On this study, we used vascular graft and human cord blood derived stem cells to find an alternative treatment solution to this problem. MATERIAL AND METHODS: We used 21 female Wistar rats on our study. They were anesthetized with ketamine and we studied right hind limbs. On Group 1, we did a full layer cut on the right sciatic nerve. On Group 2, we did a full layer cut on the right sciatic nerve, and we covered synthetic vascular graft on cut area. On Group 3, we did a full layer cut on right sciatic nerve, and we covered the area with stem cell applied vascular graft. RESULTS: At the end of postoperative 8. weeks, we performed EMG on the rats. When we compared healthy and degenerated areas as a result of EMG, we found significant amplitude differences between the groups on healthy areas whereas there was no significant difference on degenerated areas between the groups. Then we re-opened the operated area again to reveal the sciatic nerve cut area, and we performed electron microscope evaluation. On the stem cell group, we observed that both the axon and the myelin sheet prevented degeneration. CONCLUSION: This study is a first on using synthetic vascular graft and cord blood derived CD34+ cells in peripheral nerve degeneration. On the tissues that were examined with electron microscope, we observed that CD34+ cells prevented both axonal and myelin sheath degeneration. Nerve tissue showed similar results to the control group, and the damage was minimal. © 2018 Ali Yilmaz, Abdullah Topcu, Cagdas Erdogan, Levent Sinan Bir, Barbaros Sahin, Gulcin Abban, Erdal Coskun, Ayca Ozkul
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