Charged Particle Dynamics in the Field of a Slowly Rotating Compact Star

We study the dynamics of a charged particle in the field of a slowly rotating compact star in the gravitoelectromagnetic approximation to the geodesic equation . The star is assumed to be surrounded by an ideal, highly conducting plasma (taken as a magnetohydrodynamic fluid) with a stationary, axially symmetric electromagnetic field. The general relativistic Maxwell equations are solved to obtain the effects of the background spacetime on the electromagnetic field in the linearized Kerr spacetime. The equations of motion are then set up and solved numerically to incorporate the gravitational as well as the electromagnetic effects. The analysis shows that in the slow rotation approximation the frame dragging effects on the electromagnetic field are absent. However the particle is directly effected by the rotating gravitational source such that close to the star the gravitational and electromagnetic field produce contrary effects on the particle's trajectory.Comment: 10 pages, 6 figures in B & W PostScript Forma

A post-Keplerian parameter to test gravito-magnetic effects in binary pulsar systems

We study the pulsar timing, focusing on the time delay induced by the gravitational field of the binary systems. In particular, we study the gravito-magnetic correction to the Shapiro time delay in terms of Keplerian and post-Keplerian parameters, and we introduce a new post-Keplerian parameter which is related to the intrinsic angular momentum of the stars. Furthermore, we evaluate the magnitude of these effects for the binary pulsar systems known so far. The expected magnitude is indeed small, but the effect is important per se.Comment: 6 pages, RevTeX, 1 eps figure, accepted for publication in Physical Review D; references adde

Doppler Effects from Bending of Light Rays in Curved Space-Times

We study Doppler effects in curved space-time, i.e. the frequency shifts induced on electromagnetic signals propagating in the gravitational field. In particular, we focus on the frequency shift due to the bending of light rays in weak gravitational fields. We consider, using the PPN formalism, the gravitational field of an axially symmetric distribution of mass. The zeroth order, i.e. the sphere, is studied then passing to the contribution of the quadrupole moment, and finally to the case of a rotating source. We give numerical estimates for situations of physical interest, and by a very preliminary analysis, we argue that analyzing the Doppler effect could lead, in principle, in the foreseeable future, to the measurement of the quadrupole moment of the giant planets of the Solar System.Comment: 16 pages, 2 EPS figures; to appear in the International Journal of Modern Physics

The Ground CO2 Mapper. An innovative tool for the rapid and precise mapping of CO2 leakage distribution

The recently developed Ground CO2 Mapper (“Mapper” for short) is an inexpensive, light, robust, and low power consuming tool for determining the distribution of CO2 at the soil-atmosphere contact as an indicator of CO2 leakage. The basic premise behind the Mapper is that the contact between the ground surface and the atmosphere represents an interval where CO2 leaking from the subsurface can accumulate in anomalous concentrations due to two mechanisms, the higher density of CO2 with respect to air and the tendency of wind speed (and thus mixing) to approach zero near the ground surface due to frictional drag. Because of its measurement target and the tool’s very rapid response time, Mapper surveys can be conducted very quickly at a high sampling density, yielding accurate maps of CO2 spot anomalies. The unit can be used by anyone and deployed within only 5-10 minutes after sensor and GPS signal warm-up. Here we describe the Mapper and present results from a site of natural diffuse CO2 degassing in central Italy

Gravitomagnetism and the Speed of Gravity

Experimental discovery of the gravitomagnetic fields generated by translational and/or rotational currents of matter is one of primary goals of modern gravitational physics. The rotational (intrinsic) gravitomagnetic field of the Earth is currently measured by the Gravity Probe B. The present paper makes use of a parametrized post-Newtonian (PN) expansion of the Einstein equations to demonstrate how the extrinsic gravitomagnetic field generated by the translational current of matter can be measured by observing the relativistic time delay caused by a moving gravitational lens. We prove that measuring the extrinsic gravitomagnetic field is equivalent to testing relativistic effect of the aberration of gravity caused by the Lorentz transformation of the gravitational field. We unfold that the recent Jovian deflection experiment is a null-type experiment testing the Lorentz invariance of the gravitational field (aberration of gravity), thus, confirming existence of the extrinsic gravitomagnetic field associated with orbital motion of Jupiter with accuracy 20%. We comment on erroneous interpretations of the Jovian deflection experiment given by a number of researchers who are not familiar with modern VLBI technique and subtleties of JPL ephemeris. We propose to measure the aberration of gravity effect more accurately by observing gravitational deflection of light by the Sun and processing VLBI observations in the geocentric frame with respect to which the Sun is moving with velocity 30 km/s.Comment: 16 pages, no figure

[The role of endoscopy in gastroenteropancreatic neuroendocrine tumors].

[The role of endoscopy in gastroenteropancreatic neuroendocrine tumors]. [Article in Italian] Magno L, Sivero L, Napolitano V, Ruggiero S, Fontanarosa G, Massa S. Source Dipartmento di Chirurgia Generale, Geriatrica ed Endoscopia Diagnostica ed Geriatrica, Universitá degli Studi, Federico II di Napoli. Abstract Versione italiana Riassunto: Il ruolo dell'endoscopia nei tumori neuroendocrini gastroenteropancreatici. L. Magno, L. Sivero, V. Napolitano, S. Ruggiero, G. Fontanarosa, S. Massa I tumori neuroendocrini (NET) gastro-entero-pancreatici (GEP) sono neoplasie rare che originano dalle cellule neuroendocrine del tubo digerente e del pancreas. L'endoscopia digestiva e l'ecoendoscopia rivestono un ruolo importante nella diagnosi, stadiazione e sorveglianza dei pazienti con NET. Inoltre, in casi selezionati, le tecniche endoscopiche operative consentono il trattamento di queste neoplasie in fase precoce. English version Summary: The role of endoscopy in gastroenteropancreatic neuroendocrine tumors. L. Magno, L. Sivero, V. Napolitano, S. Ruggiero, G. Fontanarosa, S. Massa Gastroenteropancreatic (GEP) neuroendocrine tumors (NET) are rare neoplasia arisen from neuroendocrine cells present in the gut mucosa and pancreas. Digestive endoscopy and endoscopic ultrasonography play a relevant role in NET diagnosis, stadiation and surveillance. Moreover, in selected patients, surgical endoscopy allows the tratment of these cancers at an early stage

Non-volcanic CO2 and CH4 degassing in an actively extending orogen, southern Apennines, Italy

The southern Apennines fold and thrust belt has been undergoing post-orogenic extension since ca. 700 kyr. Crustal extension controls active tectonics and seismogenesis in the mountain chain [1], with seismicity being characterized by low to moderate magnitude events punctuated by strong earthquakes [2]. Effective decoupling between deep and shallow structural levels is related to the strong rheological contrast produced by a fluid-saturated, clay-rich mélange zone interposed between buried autochthonous carbonates – continuous with those exposed in the Apulian foreland – and the allochthonous units. This mélange zone also acts as a seal preventing the migration of deep-seated aqueous fluids – as well as oil in the Basilicata region, which hosts the largest Europe’s onshore oil fields – towards the surface. On the other hand, the mountain belt is characterized by substantial gas flow, recorded as both distributed soil gas emissions and vigorous gas vents, associated with active faults at the surface. We measured a CO2 flux up to 34000 g/m-2 per day at a gas vent, as well as large amounts of He (up to 52 ppm), Rn (up to 228 kBq/m3) and CH4 (up to 5000 ppm). Overpressured CO2, which has been proposed as triggering normal fault earthquakes in the Apennines, has been interpreted as mostly of mantle origin. However, our new results from isotope analyses carried out on the carbon contained in both CO2 and CH4 indicate a dominant thermogenic origin for these gases, probably associated with the emplacement of magmatic sills within the lower section of the thick carbonate platform succession occurring at the base of the sedimentary cover in the southern Apennines. Our results bear major implication concerning the postulated occurrence of crustal faults allowing fluids to migrate directly from mantle depths to the surface