6,170 research outputs found

    The Relative Space: Space Measurements on a Rotating Platform

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    We introduce here the concept of relative space, an extended 3-space which is recognized as the only space having an operational meaning in the study of the space geometry of a rotating disk. Accordingly, we illustrate how space measurements are performed in the relative space, and we show that an old-aged puzzling problem, that is the Ehrenfest's paradox, is explained in this purely relativistic context. Furthermore, we illustrate the kinematical origin of the tangential dilation which is responsible for the solution of the Ehrenfest's paradox.Comment: 14 pages, 2 EPS figures, LaTeX, to appear in the European Journal of Physic

    Violation of the phase space general covariance as a diffeomorphism anomaly in quantum mechanics

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    We consider a topological quantum mechanics described by a phase space path integral and study the 1-dimensional analog for the path integral representation of the Kontsevich formula. We see that the naive bosonic integral possesses divergences, that it is even naively non-invariant and thus is ill-defined. We then consider a super-extension of the theory which eliminates the divergences and makes the theory naively invariant. This super-extension is equivalent to the correct choice of measure and was discussed in the literature. We then investigate the behavior of this extended theory under diffeomorphisms of the extended phase space and despite of its naive invariance find out that the theory possesses anomaly under nonlinear diffeomorphisms. We localize the origin of the anomaly and calculate the lowest nontrivial anomalous contribution.Comment: 36 page

    Hydrogeochemistry of Magra Valley (Italy) Aquifers: Geochemical Background of an Area Investigated for Seismic Precursors

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    AbstractWe present the results of a hydrogeochemical survey of 111 springs and wells from Magra Valley, a seismic area located in northern Tuscany, Italy. This survey was aimed at defining the geochemical background and the underground fluid circulation scheme of an area currently investigated for earthquake precursory phenomena, with the final goal of identifying a suitable location for installation of a continuous automatic monitoring station for the remote control of hydrogeochemical parameters. Six springs of the project were identified suitable for the purpose, and the Equi Na-Cl-type spring emerged as the best candidate for the installation of a monitoring station

    Bulk Cr tips for scanning tunneling microscopy and spin-polarized scanning tunneling microscopy

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    A simple, reliable method for preparation of bulk Cr tips for Scanning Tunneling Microscopy (STM) is proposed and its potentialities in performing high-quality and high-resolution STM and Spin Polarized-STM (SP-STM) are investigated. Cr tips show atomic resolution on ordered surfaces. Contrary to what happens with conventional W tips, rest atoms of the Si(111)-7x7 reconstruction can be routinely observed, probably due to a different electronic structure of the tip apex. SP-STM measurements of the Cr(001) surface showing magnetic contrast are reported. Our results reveal that the peculiar properties of these tips can be suited in a number of STM experimental situations

    The real-time earthquake monitoring system in Italy

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    As regards the transmission vectors – one of the most critical points of a seismic network – we adopted a mixed strategy: half of the stations are connected through satellite links, and half through cable links. The use of satellite transmission presents several advantages: the link is very robust, the constraints for site selection are weak, and the cost is lower than telephone lines. As regards the terrestrial cable links, we use INGV digitizers (named GAIA), protected IP connections of the Italian Public Administration Network (RUPA): site selection is more delicate, and a compromise must be found between low environmental noise and availability of network infrastructures

    Improvement in the removal of micropollutants at Porto Marghera industrial wastewaters treatment plant by MBR technology.

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    This paper deals with the case of one of the most important industrial application of membrane technology in the world: the upgrading of the main industrial wastewater treatment plant (WWTP) of the petrochemical site of Porto Marghera, Northern Italy, completed on December 2005 and tested on September 2006. It describes the principal interventions of the plant upgrading and it discusses the removal obtained during the test periods for conventional pollutants as well as for micropollutants. The plant upgrading consisted of a series of improvements of the existing industrial WWTP, in order to increase the removal efficiency of the total suspended solids and the associate removal of ten micropollutant compounds, the so called forbidden substances. The most important intervention was the conversion of the existing activated sludge section into a membrane biological reactor, in order to guarantee adherence to the severe limits imposed by the special law issued to protect the Venice Lagoon, with particular reference to the mentioned 10 forbidden compounds. The experimental results and the numerous test-runs conducted confirmed the respect of the legal limits for the pollutants in the final effluent as well of the required removal rates for the different parameters. Therefore, the upgraded treatment plant was declared agreeing with the approved design

    Semi-Teleparallel Theories of Gravitation

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    A class of theories of gravitation that naturally incorporates preferred frames of reference is presented. The underlying space-time geometry consists of a partial parallelization of space-time and has properties of Riemann-Cartan as well as teleparallel geometry. Within this geometry, the kinematic quantities of preferred frames are associated with torsion fields. Using a variational method, it is shown in which way action functionals for this geometry can be constructed. For a special action the field equations are derived and the coupling to spinor fields is discussed.Comment: 14 pages, LaTe

    Dysregulation of the Autonomous Nervous System in Patients with Temporomandibular Disorder: A Pupillometric Study

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    The role of the autonomic nervous system (ANS) was recently investigated in Temporomandibular disorders (TMD). Several authors argue that in subjects with TMD there is a dysregulation of ANS. Recent literature support that Pupillometry is a simple non-invasive tool to study ANS. The aim of this study was to investigate the relationship between TMD and ANS activity using pupillometry recording in Infrared light at rest Mandible Position (RP); Infrared light at Forced Habitual Occlusion (FHO); Yellow-green light at RP; Yellow-green light at FHO. Forty female subjects were enrolled: 20 case patients showed TMD based on the Research Diagnostic Criteria for TMD, and 20 control patients, aged matched, had no signs or symptoms of TMD. Statistical analysis was performed on average pupil size. Ratio between pupil size in FHO and RP (FHO/RP ratio) and yellow-green and infrared (light/darkness ratio) lighting were carried out. Within group differences of pupil size and of "ratio" were analyzed using a paired t test, while differences of pupil size between groups were tested using an unpaired t test. Statistical comparisons between groups showed no significant differences of absolute values of pupil dimension in RP and FHO, both in yellow-green and in infrared lighting. In addition, there were no significant differences within groups comparing RP and FHO in yellow-green light. In within group comparison of pupil size, differences between RP and FHO were significant in infrared conditions. Control subjects increased, whereas TMD patients decreased pupil size at FHO in infrared lightening. FHO/RP ratio in darkness and light/darkness ratio in RP were significantly different between groups. Taken together, these data suggest that TMD subjects have an impairment of the sympathetic-adrenergic component of the ANS to be activated under stress. The present study provides preliminary pupillometric data confirming that adrenergic function is dysregulated in patients with TMD

    Photon deflection and precession of the periastron in terms of spatial gravitational fields

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    We show that a Maxwell-like system of equations for spatial gravitational fields g\bf g and B\bf B (latter being the analogy of a magnetic field), modified to include an extra term for the B\bf B field in the expression for force, leads to the correct values for the photon deflection angle and for the precession of the periastron
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