2,003 research outputs found

    Communications of the median nerve in foetuses

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    Background: Communications between the median, ulnar and musculocutaneous nerves in the arm, forearm and hand were reported in adult cadaveric and electrophysiological studies. These communicant branches may lead conflicting clinical and electrodiagnostic outcomes. While there are many studies on adult patients or cadavers, there is poor regarding foetuses. The present study was conducted to examine the frequencies of these communications and their coexistences in human foetuses.Materials and methods: Anterior aspect of the forearms of 50 foetuses (29 females, 20 males, and 1 unknown) were dissected bilaterally (totally 100 sides) for this purpose.Results: Communications between the median and the musculocutaneous nerves in the arm were found unilaterally in 4%. Communications from the median to the ulnar nerve in the forearm were encountered unilaterally in 22%, and bilaterally in 12%; from the ulnar to the median nerve in the hand unilaterally in 28%, and bilaterally in 12%. Coexistence of all these variations was not encountered in any foetus. But coexistence of two different types of communicant branch was encountered in 4%.Conclusions: Precise knowledge of nerve communications, variations and rate of coexistences in foetuses may have significance for clinicians and researchers dealing with subjects in foetal period

    Common fixed point results for four mappings on partial metric spaces

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    We give fixed point results for four mappings which satisfy almost generalized contractive condition on partial metric space and we support the results with an example

    Corrosion behaviour of coatings on 304 steel

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    The aim of this study is to determine the corrosion characteristics of 304 steel by the methods of Tafel extrapolation, linear polarization and electrochemical impedance spectroscopy (EIS). The steel surface is covered with nickel as electrochemical Watt's bath. Additionally, polyaniline (PANI) is synthesized on the steel electrode covered with nickel by the method of electrochemical cyclic voltammetry method. The effect of single and double coats of steel on corrosion resistance is examined in 3.5 % NaCl, 1N NaOH and 1N HCl solutions for the waiting time of 1, 48, 120 and 168 h. The surface morphology of steel, which is uncovered, is examined by SEM-EDX and the polyaniline is also examined in the same way. As well as the one covered with Ni + polyaniline is examined in the same way too. The synthesized polyaniline on the surface is analyzed by FTIR spectrum. Double coatings (Ni + polyaniline) has showed better corrosion resistance than single coating (polyaniline). Ni + polyaniline coatings in 1 N NaOH and 1 N HCl solutions has showed better corrosion resistance than polyaniline coating. The corrosion current of the steel covered with Ni + polyaniline in 1 N HCl and 1 N NaOH solutions is lower than the corrosion current of polyaniline coating. SEM-EDX analyses have showed that the surface covered with Ni + polyaniline is more homogenous and compact. This result is also convenient with the electrochemical experiment results

    Bifurcation of drift shells near the dayside magnetopause

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    Close to the dayside magnetopause, there is a region of space where each field line has two magnetic field minima, one near each cusp. That region is located around local noon, and extends about 1-2 R-e from the magnetopause. Particles that enter this region with equatorial pitch angles sufficiently close to 90 degrees will cross the dayside not along an equatorial path, but along one of the two branches on either side of the equatorial plane. The two branches are joined again past local noon. This process of drift-shell bifurcation (DSB) is nonadiabatic even under static conditions. Two physical mechanisms can cause this nonadiabaticity: one that is operative for nearly all magnetospheric magnetic field configurations and another that depends on a particular combination of north-south and east-west asymmetry in the magnetic field. This paper deals only with the first mechanism. For configurations with north-south and east-west symmetry, DSB changes the second invariant I of the motion by a small amount that is of the order of the gyroradius (the first invariant is intact). For near-equatorial particles (I approximate to 0) the change can be significantly larger. Assuming north-south and dawn-dusk symmetry, we present general theoretical expressions for the second-invariant jump Delta I, which can be applied to a variety of magnetic field models. The results show that Delta I is sensitively dependent on the bounce phase of the particle at the bifurcation line. The RMS value of Delta I over a bounce-phase ensemble increases with decreasing mirror field and with increasing kinetic energy. We verify these results with test-particle simulations using model magnetic fields.Publisher's Versio

    Trajectories of charged particles trapped in Earth's magnetic field

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    I outline the theory of relativistic charged-particle motion in the magnetosphere in a way suitable for undergraduate courses. I discuss particle and guiding center motion, derive the three adiabatic invariants associated with them, and present particle trajectories in a dipolar field. I provide twelve computational exercises that can be used as classroom assignments or for self-study. Two of the exercises, drift-shell bifurcation and Speiser orbits, are adapted from active magnetospheric research. The Python code provided in the supplement can be used to replicate the trajectories and can be easily extended for different field geometries.Comment: 10 pages, 7 figures. Submitted to American Journal of Physic

    Evaluating Current Logistics Facilities with Analytical Hyepapchy Process (AHP) and Geographical Information Systems (GIS)

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    Abstract. Logistics facilities which have important position within logistics supply chain are established in order for the demanded goods to be supplied on time, with the minimum cost and in the shortest duration. Given the cost and time factors, the location of such facilities should be selected very carefully and effectively. Especially, a quick settlement in logistics manner is experienced depending on transportation network, work force, proximity to market and raw materials of the times following the industrialization period after establishing the Republic. Nowadays, with the development of transportation and the communication systems as well as technology transportation costs decreased and the facilities and possibilities transport from one place to another increased. For this reason, like the private sector the public institutions and organizations began to shrink, shut down or merge their facilities. This situation was brought to reconsider the existing facilities. The purpose of this study is to evaluate and analyze current six logistics facilities with Analytical Hierarchy Process (AHP) and Geographical Information Systems (GIS). Analyses results will contribute the decision of revising logistics facilities for which are planned to be restructured. Moreover, suggestions are presented for proper ones to continue operating, for improper ones to get closed or transferred to another place.Keywords. Analytic Hierarchy Process, (AHP), Geographic Information Systems, (GIS), Facility Site Selection.JEL. J61, L86, Q55
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