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Entropic Forces in a Kerr Geometry: a Link with Rotational Properties

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Communications in Theoretical Physics 2011年第4期55卷 594-596页

作者： A.Curir inaf-Astronomical Observatory of Torino

The recent thermodynamical interpretation of the field equations of gravity is revisited and extended to the killing horizons linked to the rotation （Kerr black holes）. An entropic force can be defined also for these horizons which are not event horizons but show thermodynamical features that in previous works were used to explain the rotational properties of Kerr solutions. Such entropic force is needed to describe the energetic processes, which do not change the usual thermal entropy of the rotating black hole （reversible transformations, superradiance）.

关键词： quantum aspects of black holes evaporation thermodynamics

Quasi-Biennial Modulation of the Solar Neutrino Flux: A “Telescope” for the Solar Interior

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Journal of Modern Physics 2013年第4期4卷 49-56页

作者： Loris D’Alessi Antonio Vecchio Vincenzo Carbone Monica Laurenza Marisa Storini Dipartimento di Fisica Università della Calabria Cosenza Italy inaf/iaps-Roma Via del Fosso del Cavaliere Roma Italy

An oscillating magnetic field deep within the solar radiative region can significantly alter the helioseismic g-modes. The presence of density gradients along g-modes, can excite Alfvén waves resonantly, the resulting waveforms show sharp spikes in the density profile at radii comparable with the neutrino’s resonant oscillation length. This process should explain the observed quasi-biennial modulation of the solar neutrino flux. If confirmed, the coupling between solar neutrino flux and g-modes should be used as a “telescope” for the solar interior.

关键词： Solar Neutrinos Solar Cycle Solar Interior

Final results of the first phase of the PROTO-SPHERA experiment: obtainment of the full current stable screw pinch and first evidences of the jet + torus combined plasma configuration

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Plasma Science and Technology 2024年第2期26卷 31-43页

作者： Paolo MICOZZI Franco ALLADIO Alessandro MANCUSO Vincenzo ZANZA Gerarda APRUZZESE Francesca BOMBARDA Luca BONCAGNI Paolo BURATTI Francesco FILIPPI Giuseppe GALATOLA TEKA Francesco GIAMMANCO Edmondo GIOVANNOZZI Andrea GROSSO Matteo IAFRATI Alessandro LAMPASI Violeta LAZIC Simone MAGAGNINO Simone MANNORI Paolo MARSILI Valerio PIERGOTTI Giuliano ROCCHI Alessandro SIBIO Benedetto TILIA Onofrio TUDISCO FSN Dipartimento Fusione e tecnologie per la Sicurezza Nucleare ENEA Agenzia Nazionale per Le Nuove Tecnologie Energia e lo Sviluppo Economico SostenibileFrascati(Rome)00044Italy iaps Istituto di Astrofisica e Planetologia Spaziali INAF Istituto Nazionale di AstrofisicaRome O133Italy Physics Department University of Pisa Faculty of Natural Sciences Mathematics and PhysicsPisa 56127 Italy

In astrophysics, the boundary conditions for plasma phenomena are provided by nature and the astronomer faces the problem of understanding them from a variety of observations [Hester J J et al 1996 Astrophys. J. 456 225], on the other hand, in laboratory plasma experiments the electromagnetic boundary conditions become a major problem in the set-up of the machine that produces the plasma, an issue that has to be investigated step by step and to be modified and adapted with great patience, in particular in the case of an innovative plasma confinement experiment. The PROTO-SPHERA machine [Alladio F et al 2006 Nucl. Fusion 46 S613] is a magnetic confinement experiment, that emulates in the laboratory the jet + torus plasma configurations often observed in astrophysics: an inner magnetized jet of plasma centered on the(approximate) axis of symmetry and surrounded by a magnetized plasma torus orthogonal to this jet. The PROTO-SPHERA plasma is simply connected, i.e., no metal current conducting rod is linked to the plasma torus, while instead it is the inner magnetized plasma jet(in the following always called the plasma centerpost) that is linked to the torus. It is mandatory that no spurious plasma current path modifies the optimal shape of the plasma centerpost. Moreover, as the plasma torus is produced and sustained, in absence of any applied inductive electric field, by the inner plasma centerpost through magnetic reconnections [Taylor J B and Turner M F 1989 *** 29 219], it is required as well that spurious current paths do not surround the torus on its outboard, in order not to lower the efficiency of the magnetic reconnections that maintain the plasma torus at the expense of the plasma centerpost. Boundary conditions have been corrected,up to the point that the first sustainment in steady state has been achieved for the combined plasma.

关键词： laboratory plasmas magnetic confinement astrophysical plasmas

Probe lifetime around natural satellites with obliquity

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Astrodynamics 2022年第4期6卷 429-439页

作者： Marco Cinelli Hanlun Lei Emiliano Ortore Christian Circi Istituto di Astrofisica e Planetologia Spaziali(iaps) Istituto Nazionale di Astrofisica(INAF)Roma 00133Italy School of Astronomy and Space Science and Key Laboratory of Modern Astronomy and Astrophysics Ministry of EducationNanjing UniversityNanjing 210046China School of Aerospace Engineering Sapienza University of RomeRome 00138Italy Department of Astronautical Electricaland Energy EngineeringSapienza University of RomeRome 00138Italy

The dynamics of a probe orbiting a moon can be significantly influenced by the non-coincidence between the moon's equatorial and orbital ***,we performed a general analysis about the effects of the angle(obliquity)between the above-mentioned planes and of the angle(nodal phasing)between the nodal lines of the mother planet's apparent orbit and the probe orbit on the lifetime of the *** lifetime,strictly correlated to the variations in eccentricity of the probe orbit,was evaluated starting from low values of the semi-major axis,moderate eccentricity,and high inclination to offer high ground spatial resolution and extend latitudinal coverage of the natural *** investigation,carried out through numerical simulations,may be useful for identifying the optimal initial conditions of the probe's orbit elements,leading to an important increase in the probe lifetime in missions devoted to the exploration of natural satellites.

关键词： third-body effect natural satellite probe lifetime

Weighing Neutrinos in f(R) Gravity in Light of BICEP2

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Communications in Theoretical Physics 2014年第7期61卷 102-108页

作者：周晓颖何建华 Department of Physics Fudan University inaf-Observatorio Astronomico di Brera Via Emilio Bianchi

We constrain the neutrino mass in f(R) gravity using the latest observations from the Planck, BAO and BICEP2 data. We find that the measurement on the B-modes can break the degeneracy between the massive neutrinos and the f(R) gravity. We find a non-zero value of the Compton wavelengths B0 at a 68% confidence level for the f(R) model in the presence of massive neutrinos when the BICEP2 data is used. Furthermore, the tension on the tensor-to-scalar ratios between the measured values from Plank and BICEP2 is significantly reconciled in our model.

关键词： f(R) neutrinos BICEP2

Additive neurorestorative effects of exercise and docosahexaenoic acid intake in a mouse model of Parkinson’s disease

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Neural Regeneration Research 2025年第2期20卷 574-586页

作者： Olivier Kerdiles Méryl-Farelle Oye Mintsa Mi-mba Katherine Coulombe Cyntia Tremblay VincentÉmond Martine Saint-Pierre Clémence Rouxel Line Berthiaume Pierre Julien Francesca Cicchetti Frédéric Calon Facultéde pharmacie UniversitéLaval1050 Avenue de la MédecineQuebecQCCanada Axe Neuroscience Centre de recherche du CHU de Québec-UniversitéLaval(Pavillon CHUL)2705 Boulevard LaurierQuebecQCCanada Institute of Nutrition and Functional Foods QuebecQCCanada Optinutribrain International Associated Laboratory(NutriNeuro FranceINAFCanada)QuebecQCCanada Axe Endocrinologie et Néphrologie Centre de recherche du CHU de Québec-UniversitéLavalQuebecQCCanada Département de Médecine Facultéde MédecineUniversitéLavalQuebecQCCanada Département de Psychiatrie et Neurosciences Facultéde MédecineQuebecQCCanada

There is a need to develop interventions to slow or reverse the degeneration of dopamine neurons in Parkinson’s disease after *** that preclinical and clinical studies suggest benefits of dietary n-3 polyunsaturated fatty acids,such as docosahexaenoic acid,and exercise in Parkinson’s disease,we investigated whether both could synergistically interact to induce recovery of the dopaminergic ***,mice received a unilateral stereotactic injection of 6-hydroxydopamine into the striatum to establish an animal model of nigrostriatal *** weeks after lesion,animals were fed a docosahexaenoic acid-enriched or a control diet for the next 8 *** this period,the animals had access to a running wheel,which they could use or *** acid treatment,voluntary exercise,or the combination of both had no effect on(i)distance traveled in the open field test,(ii)the percentage of contraversive rotations in the apomorphine-induction test or(iii)the number of tyrosine-hydroxylase-positive cells in the substantia nigra pars ***,the docosahexaenoic acid diet increased the number of tyrosine-hydroxylase-positive terminals and induced a rise in dopamine concentrations in the lesioned *** to docosahexaenoic acid treatment or exercise alone,the combination of docosahexaenoic acid and exercise(i)improved forelimb balance in the stepping test,(ii)decreased the striatal DOPAC/dopamine ratio and(iii)led to increased dopamine transporter levels in the lesioned *** present results suggest that the combination of exercise and docosahexaenoic acid may act synergistically in the striatum of mice with a unilateral lesion of the dopaminergic system and provide support for clinical trials combining nutrition and physical exercise in the treatment of Parkinson’s disease.

关键词： 6-hydroxydopamine dopamine dopamine transporter exercise neurorestoration Parkinson’s disease polyunsaturated fatty acids omega-3

Lunar orbits for telecommunication and navigation services

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Astrodynamics 2024年第1期8卷 209-220页

作者： Marco Cinelli Emiliano Ortore Giovanni Mengali Alessandro A.Quarta Christian Circi Istituto di Astrofisica e Planetologia Spaziali(iaps) Istituto Nazionale di Astrofisica(INAF)Via del Fosso del Cavaliere 100Roma00133Italy School of Aerospace Engineering Sapienza University of RomeVia Salaria 881Rome00138Italy Department of Civil and Industrial Engineering University of PisaPisa56122Italy Department of Astronautical Electricaland Energy EngineeringSapienza University of RomeVia Salaria 851Rome00138Italy

Orbits that are frozen in an averaged model,including the effect of a disturbing body laying on the equatorial plane of the primary body and the influence of the oblateness of the primary body,have been applied to probes orbiting the *** this scenario,the main disturbing body is represented by the Earth,which is characterized by a certain obliquity with respect to the equatorial plane of the *** a consequence of this,and of the perturbing effects that are not included in the averaged model,such solutions are not perfectly ***,the orbit eccentricity,inclination,and argument of pericenter present limited variations and can be set to guarantee the fulfillment of requirements useful for lunar telecommunication missions and navigation *** advantage of this,a practical case of a Moon-based mission was investigated to propose useful solutions for potential near-future applications.

关键词： lunar orbits frozen orbits lunar telecommunications lunarnavigation services

Accretion and jet power in active galactic nuclei

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Research in Astronomy and Astrophysics 2011年第11期11卷 1266-1278页

作者： Luigi Foschini inaf-Osservatorio Astronomico di Brera Via E. Bianchi 46 23807 Merate (LC) Italy

The classical diagrams of radio loudness and jet power as a function of mass and accretion rate of the central spacetime singularity in active galactic nuclei are reanalyzed by including the data of the recently discovered powerful relativistic jets in Narrow-Line Seyfert 1 Galaxies. The results are studied in the light of the known theories of relativistic jets, indicating that, although the Blandford-Znajek mechanism is sufficient to explain the power radiated by BL Lac Objects, it falls to completely account for the power from quasars and Narrow-Line Seyfert 1 Galaxies. This favors the scenario outlined by Cavaliere ＆ D＇Elia of a composite jet, with a magnetospheric core plus a hydromagnetic component emerging when the accretion power increases and the disk becomes radiation-pressure dominated. A comparison with Galactic compact objects is also made, finding some striking similarities, indicating that since neutron stars are low-mass jet systems analogous to black holes, Narrow-Line Seyfert 1 Galaxies are low-mass counterparts of blazars.

关键词： galaxies jets-BL Lacertae objects general-quasars general-galaxies Seyfert

On the emission lines in active galactic nuclei with relativistic jets

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Research in Astronomy and Astrophysics 2012年第4期12卷 359-368页

作者： Luigi Foschini inaf-Osservatorio Astronomico di Brera Via E. Bianchi 46 23807 Merate (LC) Italy

The effect of the observed continuum emitted from a relativistic jet on the measurement of the full width at half maximum （FWHM） of an emission line is analyzed. If the jet contribution is not properly subtracted, the FWHM of the line could seem narrower than it should. The cases of an emission line detected in BL Lac objects and γ-ray Narrow-Line Seyfert 1 galaxies （γ-NLS1s） are addressed. It is shown that the smallness of the observed FWHM of the Lyα lines detected in three well-known BL Lacs is an effect due to the combined action of both the relativistic jet and a weak accretion disk. Once the Doppler boosting effect of the jet continuum is removed, the intrinsic FWHM values of the lines are found to be in the usual range. By contrast, the narrow permitted lines in γ-NLS1s are really narrow, since the disk and the lines are much more powerful. This also confirms that γ-NLS1 is really a new class of γ-ray emitting AGN, different from blazars and radio galaxies.

关键词： line: profiles—galaxies: jets—BL Lacertae Objects: general—galaxies: Seyfert