48 research outputs found
On the dynamical evolution of a young planetary system
No full textThe dynamical evolution of planetary and protoplanetary structures represents one of the major challenges for the modern Computational Astrophysics. The focus of our investigation is to study the dynamical evolution of a young planetary system both in isolation as well as embedded in a typical stellar open cluster. We simulate the whole system using the code GASPH (Pinto, Capuzzo-Dolcetta & Magni, 2019), an optimized SPH (Smoothed Particle Hydrodynamics) code which deals with self-gravity by mean of a tree-based scheme. Our young planetary system is composed by a central, solar like, star surrounded by a gaseous disk containing a fully formed Jovian planet. The disk is assumed as a marginally self-gravitating, ideal, gas and, to study its evolutionary properties, it is parameterized as an ensemble of SPH particles with an initial mass of 0.01 solar masses, essentially the value of the so called minimum solar mass nebula. We set our young planetary system in a typical open star cluster in order to study the gravitational perturbations induced by stellar flybys at varying the mass of the stellar perturber from 0.5 to 8 solar masses. We change the perturber periastron in the range of 100 - 500 AU and ,in order to investigate prograde and retrograde configurations, we vary its orbital inclination from 0 to 180 degrees. We followed the evolution of orbital planetary parameters like the semi-major axis and eccentricity. In addition, we investigated the accretion mass rate of the planet inside the disk, both during the stellar flyby and in the case without any external perturbation. In this frame, the dynamical evolution of the disk is quantified by the analysis of its Lagrangian radii. We confirmed the relevant role of the disk to catalyze the gravitational perturbation from the stellar perturber to the Jovian planet, converting the impulsive action of the stellar flyby to a softer long-time planet-disk interaction. We show the different role of retrograde and prograde perturber orbits for the dynamical evolution of a young planetary system in a stellar environment. Finally, our theoretical, simulative, study could be a support for exploratory astrophysics surveys in stellar clusters, aiming to the search of new young exoplanetary systems in such environments
Dynamical evolution of a young planetary system: stellar flybys in co-planar orbital configuration
No full textStellar flybys in star clusters may perturb the evolution of young planetary systems in terms of disk truncation, planetary migration and planetary mass accretion. We
investigate the feedback of a young planetary system during a single close stellar encounter in a typical open young stellar cluster. We consider 5 masses for the stellar perturbers:
0.5, 0.8, 1, 3 and 8 M, in coplanar, prograde and retrograde orbits respect to the planetary disk, varying the perturberhost star orbital periastron from 100 au to 500 au. We have
made 3D modelizations with the smooth particle hydrodynamics code GaSPH of a system composed by a solar type star surrounded by a low density disk where a giant planet is
embedded in. We focus on the dynamical evolution of global parameters characterizing the disk and the planet, like the
Lagrangian radius containing the 63.2% of the mass of the disk, the distance of the planet to its host star, the planet orbital eccentricity and the planetary mass accretion. We find
that the most part of the simulated systems show a significant disk truncation after a single close encounter, a final orbital distance of the Jovian, from the central star, lower
than the unperturbed case and, finally, the perturbed systems show a final mass accretion of the Jovian planet larger than the non-perturbed case. Therefore, stellar flybys significantly perturb the dynamics of a young planetary system, regardless the orbital configuration of the stellar perturber.
In such experiments, the final disk radius and the orbital parameters of the Jovian planet are considerably affected by the stellar close encounter
Statistical analysis of the first results of the SPHERE GTO Survey
No full textThis dissertation reports about a statistical analysis of the first 88
targets observed by the science channel IFS (Integral-Field-Spectrograph)
during the SPHERE Guaranteed Time Survey (GTO). The final
goal of this work is to put some initial constraints on the frequency
of giant planets in wide orbits, on their mass distribution, on their
semi-major axis distribution and possibly on the formation mechanism.
In the first chapter we briefly present the two theories aimed at
explaining the planet formation mechanism: the “core accretion”
and the “disk instability”.
In the second chapter we introduce the direct-imaging technique
to discover young and self-luminous exoplanets and in the same
chapter we present a new instrument optimized to perform direct
imaging: SPHERE a Spectro-Polarimetric High-contrast-Exoplanet-
REsearch.
In the third chapter we describe the Guaranteed Time of Observation
(GTO) survey SHINE, which is currently ongoing on SPHERE,
the target selection and finally the results of the first two semesters
of the survey.
In the fourth outline we describe the statistical formalism used for
the analysis and in particular the Quick-MESS code (Quick Multipurpose
Exoplanet Simulation System): a fast alternative code to
the classic Monte-Carlo tools for the statistical analysis of exoplanet
direct imaging surveys.
The results of our analysis are given in the fifth chapter and
finally we compare our data with results from other surveys in sixth
chapter.
Although still exploratory, because the candidates so far found
with SPHERE still require confirmation and only about 1=4 of the
targets have been observed, this analysis will provide a first test of
the methodology we plan to use once the survey is completed and
some very early results. We show that current data are compatible
with distributions, from the radial velocities, with only few planets
beyound 10 - 20 AU. The peak of the giant planet distribution
should then be at a separation not much larger than the snow-line,
in agreement with the very recent result obtained by Bryan et al.
(2016) from a combination of a radial velocity and the direct imaging
data. This is interesting because the selection criteria used in our
survey is very different, focusing on young objects and is not biased
versus system with closer planets. On the other hand, the number
of planets so far detected in our survey, while still compatible with
an extrapolation of the results by Bryan et al., is at the lower limit
of the acceptable range. Completion of the SPHERE survey will
roughly reduce at half the current error bar in the frequency of
planets at large separations (> 10 AU). This will be enough to show
if this frequency is as high as expected from Bryan et al. analysis,
or lower as suggested by our preliminary data.
Finally, we propose a distribution of the frequency of giant planets
versus the separations. The peak of distribution, in agreement
with RV and SHINE data, should be slightly out of the snow-line
as predicted by the core accretion scenario. Furthermore we note
that the positions of Jupiter and Saturn are compatible with the
peak of the overall distribution of giant planets, showing that on
this respect the Solar System does not represent an exception.ope
Correction to: Ultra-late response (> 24 weeks) to anti-CGRP monoclonal antibodies in migraine: a multicenter, prospective, observational study (Journal of Neurology, (2024), 271, 5, (2434-2443), 10.1007/s00415-023-12103-4)
No full textIn the original version of this article, degree “ERT” of author Bonassi Stefano was incorrectly written as author in author group. Author group which previously read: Piero Barbanti1,2 · Cinzia Aurilia1 · Gabriella Egeo1 · Stefania Proietti3 · Florindo D’Onofrio4 · Paola Torelli5 · Marco Aguggia6 · Davide Bertuzzo6 · Cinzia Finocchi7 · Michele Trimboli8 · Sabina Cevoli9 · Giulia Fiorentini1 · Bianca Orlando1 · Maurizio Zucco10 · Laura Di Clemente10 · Ilaria Cetta11 · Bruno Colombo11 · Monica Laura Bandettini di Poggio12 · Valentina Favoni9 · Licia Grazzi13 · Antonio Salerno14 · Antonio Carnevale15 · Micaela Robotti16 · Fabio Frediani16 · Claudia Altamura17 · Massimo Filippi11 · Fabrizio Vernieri17 · Stefano Bonassi2,4 · ERT; for the Italian Migraine Registry study group. Should have read: Piero Barbanti1,2 · Cinzia Aurilia1 · Gabriella Egeo1 · Stefania Proietti3 · Florindo D’Onofrio4 · Paola Torelli5 · Marco Aguggia6 · Davide Bertuzzo6 · Cinzia Finocchi7 · Michele Trimboli8 · Sabina Cevoli9 · Giulia Fiorentini1 · Bianca Orlando1 · Maurizio Zucco10 · Laura Di Clemente10 · Ilaria Cetta11 · Bruno Colombo11 · Monica Laura Bandettini di Poggio12 · Valentina Favoni9 · Licia Grazzi13 · Antonio Salerno14 · Antonio Carnevale15 · Micaela Robotti16 · Fabio Frediani16 · Claudia Altamura17 · Massimo Filippi11 · Fabrizio Vernieri17 · Stefano Bonassi2,3 · for the Italian Migraine Registry study group. And affiliation details for author Stefano Bonassi were incorrectly given as 2San Raffaele University, Rome, Italy 4Headache Center Neurology Unit, San Giuseppe Moscati Hospital, Avellino, Italy 2San Raffaele University, Rome, Italy 4Headache Center Neurology Unit, San Giuseppe Moscati Hospital, Avellino, Italy but should have been: 2San Raffaele University, Rome, Italy 3Clinical and Molecular Epidemiology, IRCCS San Raffaele (not 2 and 4) 2San Raffaele University, Rome, Italy 3Clinical and Molecular Epidemiology, IRCCS San Raffaele (not 2 and 4
Statistical analysis of the first results of the SPHERE GTO Survey
No full textThis dissertation reports about a statistical analysis of the first 88
targets observed by the science channel IFS (Integral-Field-Spectrograph)
during the SPHERE Guaranteed Time Survey (GTO). The final
goal of this work is to put some initial constraints on the frequency
of giant planets in wide orbits, on their mass distribution, on their
semi-major axis distribution and possibly on the formation mechanism.
In the first chapter we briefly present the two theories aimed at
explaining the planet formation mechanism: the “core accretion”
and the “disk instability”.
In the second chapter we introduce the direct-imaging technique
to discover young and self-luminous exoplanets and in the same
chapter we present a new instrument optimized to perform direct
imaging: SPHERE a Spectro-Polarimetric High-contrast-Exoplanet-
REsearch.
In the third chapter we describe the Guaranteed Time of Observation
(GTO) survey SHINE, which is currently ongoing on SPHERE,
the target selection and finally the results of the first two semesters
of the survey.
In the fourth outline we describe the statistical formalism used for
the analysis and in particular the Quick-MESS code (Quick Multipurpose
Exoplanet Simulation System): a fast alternative code to
the classic Monte-Carlo tools for the statistical analysis of exoplanet
direct imaging surveys.
The results of our analysis are given in the fifth chapter and
finally we compare our data with results from other surveys in sixth
chapter.
Although still exploratory, because the candidates so far found
with SPHERE still require confirmation and only about 1=4 of the
targets have been observed, this analysis will provide a first test of
the methodology we plan to use once the survey is completed and
some very early results. We show that current data are compatible
with distributions, from the radial velocities, with only few planets
beyound 10 - 20 AU. The peak of the giant planet distribution
should then be at a separation not much larger than the snow-line,
in agreement with the very recent result obtained by Bryan et al.
(2016) from a combination of a radial velocity and the direct imaging
data. This is interesting because the selection criteria used in our
survey is very different, focusing on young objects and is not biased
versus system with closer planets. On the other hand, the number
of planets so far detected in our survey, while still compatible with
an extrapolation of the results by Bryan et al., is at the lower limit
of the acceptable range. Completion of the SPHERE survey will
roughly reduce at half the current error bar in the frequency of
planets at large separations (> 10 AU). This will be enough to show
if this frequency is as high as expected from Bryan et al. analysis,
or lower as suggested by our preliminary data.
Finally, we propose a distribution of the frequency of giant planets
versus the separations. The peak of distribution, in agreement
with RV and SHINE data, should be slightly out of the snow-line
as predicted by the core accretion scenario. Furthermore we note
that the positions of Jupiter and Saturn are compatible with the
peak of the overall distribution of giant planets, showing that on
this respect the Solar System does not represent an exception
Modelling noise propagation generated by forest operations: a case study in Southern Italy
No full textNoise is defined as an undesired sound that constitutes an unwarranted disturbance potentiality modifying animal behaviour or normal functioning. Forest operations commonly involve the use of equipment and machines that can produce noise and be a potential permanent or temporary disturbance for the wildlife. This study simulates noise propagation in a natural area generated during coppice stand harvesting by direct field noise measurements and the application of a specific GIS model. Two working phases were investigated: felling and yarding operations. Two potential systems were analyzed for the yarding operations: a) yarding by mobile cable yarder and b) skidding by tractor with a three point log grapple. The results are reported in terms of excess noise area for the third-octave bandwidths with the centre in 500 Hz, 1000 Hz and 2000 Hz. Felling by chainsaws presented the largest area where noise exceeds the ambient natural noise, while in the case of yarding, mobile cable yarding operations presented a smaller area of excess noise than skidding by tractor
Correction to: Diffusion, outcomes and implementation of minimally invasive liver surgery: a snapshot from the I Go MILS (Italian Group of Minimally Invasive Liver Surgery) Registry (Updates in Surgery, (2017), 69, 3, (271-283), 10.1007/s13304-017-0489-x)
No full textA technical error led to incorrect rendering of the author group in this article. The correct authorship is as follows: Luca Aldrighetti, Francesca Ratti, Umberto Cillo, Alessandro Ferrero, Giuseppe Maria Ettorre, Alfredo Guglielmi, Felice Giuliante, Fulvio Calise on behalf of the Italian Group of Minimally Invasive Liver Surgery (I GO MILS) The collaborators are: Raffaele Dalla Valle, AOU Parma, Parma; Vincenzo Mazzaferro, Istituto Nazionale Tumori, Milano; Elio Jovine, Ospedale Maggiore, Bologna; Luciano Gregorio De Carlis, Ospedale Niguarda Ca’ Granda, Milano; Ugo Boggi, AOU Pisana, Pisa; Salvatore Gruttadauria, ISMETT, Palermo; Fabrizio Di Benedetto, AOU Policlinico di Modena, Modena; Paolo Reggiani, Ospedale Maggiore Policlinico, Milano; Stefano Berti, Ospedale Civile S.Andrea, La Spezia; Graziano Ceccarelli, Ospedale San Donato, Arezzo; Leonardo Vincenti, AOU Consorziale Policlinico, Bari; Giulio Belli, Ospedale SM Loreto Nuovo, Napoli; Guido Torzilli, Istituto Clinico Humanitas, Rozzano; Fausto Zamboni, Ospedale Brotzu, Cagliari; Andrea Coratti, AOU Careggi, Firenze; Pietro Mezzatesta, Casa di Cura La Maddalena, Palermo; Roberto Santambrogio, AO San Paolo, Milano; Giuseppe Navarra, AOU Policlinico G. Martino, Messina; Antonio Giuliani, AO R.N. Cardarelli, Napoli; Antonio Daniele Pinna, Policlinico Sant’Orsola Malpighi, Bologna; Amilcare Parisi, AO Santa Maria di Terni, Terni; Michele Colledan, AO Papa Giovanni XXIII, Bergamo; Abdallah Slim, AO Desio e Vimercate, Vimercate; Adelmo Antonucci, Policlinico di Monza, Monza; Gian Luca Grazi, Istituto Nazionale Tumori Regina Elena, Roma; Antonio Frena, Ospedale Centrale, Bolzano; Giovanni Sgroi, AO Treviglio-Caravaggio, Treviglio; Alberto Brolese, Ospedale S.Chiara, Trento; Luca Morelli, AOU Pisana, Pisa; Antonio Floridi, AO Ospedale Maggiore, Crema; Alberto Patriti, Ospedale San Matteo degli Infermi, Spoleto; Luigi Veneroni, Ospedale Infermi AUSL Romagna, Rimini; Giorgio Ercolani, Ospedale Morgagni Pierantoni, Forlì; Luigi Boni, AOU Fondazione Macchi, Varese; Pietro Maida, Ospedale Villa Betania, Napoli; Guido Griseri, Ospedale San Paolo, Savona; Andrea Percivale, Ospedale Santa Corona, Pietraligure; Marco Filauro, AO Galliera, Genova; Silvio Guerriero, Ospedale San Martino, Belluno; Giuseppe Tisone, Policlinico Tor Vergata, Roma; Raffaele Romito, AOU Maggiore della Carità, Novara; Umberto Tedeschi, AOU Integrata Verona, Verona; Giuseppe Zimmitti, Fondazione Poliambulanza, Brescia. © 2017, Italian Society of Surgery (SIC)
Hypnerotomachia Poliphili e Roma. Metodologie euristiche per lo studio del Rinascimento
No full textFino ad ora sottovalutati perché difficilmente dimostrabili, in realtà gli scambi culturali tra gli artisti e i letterati hanno contribuito a caratterizzare l’originalità del Rinascimento italiano. Pinturicchio lavora al pavimento del Duomo di Siena e nella
Libreria Piccolomini appaiono evidenti citazioni del Polifilo. Andrea Mantegna e Pomponio Leto, fondatore dell’Accademia Romana, sono compresenti nell’Accademia dei Vertunni di Brescia mentre Giovanni Bellini, che aveva una vigna a Roma dove venne ritrovato uno specchio antico, dipingeva il ritratto di Raffaele Zovenzoni autore dei celebri versi in onore di Francesco Colonna antiquario. Tra gli estimatori del Polifilo anche Jacopo Galli, il banchiere che comprò il Bacco, prima opera romana del giovane
Michelangelo Buonarroti. Baldassarre Peruzzi riuscì a rifondare Carpi secondo l’immagine di una novella Roma usando i consigli e le direttive del colto Alberto III Pio allievo di Aldo Manuzio il vecchio, editore dell’Hypnerotomachia. Il pittore Amico Aspertini, come anche l’antiquario carmelitano Fabrizio Ferrarini, si ispirarono ai fregî antichi della città di Roma che furono valorizzati in modo esemplare dalle xilografie in stile egizio del Polifilo di Francesco Colonna romano signore di Palestrina.Neglected as difficult to prove until now, the cultural exchanges among artists and men of letters chiefly contributed to shape the originality of the Italian Renaissance. Pinturicchio worked for the pavement decoration of the Sienese Duomo and the Libreria Piccolomini hosts overt references to the Hypnerotomachia. Andrea Mantegna and Pomponio Leto, who was the founder of the Accademia Romana, are both attested in the Accademia dei Vertunni in Brescia, while Giovanni Bellini, who owned a land in Rome in which an ancient mirror was found, painted the portrait of Raffaele Zovenzoni, the author of renowned versed dedicated to the antiquarian Francesco Colonna. Among the appraisers of the Hypnerotomachia, Jacopo Galli was the banker who purchased the Bacchus, the first Roman work of the young Michelangelo Buonarroti. Baldassarre Peruzzi succeeded in reshaping Carpi according to the model of a novel Rome, profiting from the suggestions and guidelines of the erudite Alberto III Pio, a pupil of Aldo Manuzio the Elder, who published the Hypnerotomachia. The painter Amico Aspertini, as well as the Carmelite antiquarian Fabrizio Ferrarini, took inspiration from the antique friezes of Rome, which were remarkably enhanced by the Egyptian-like woodcuts in the Hypnerotomachia, written by the Roman Francesco Colonna nobleman of Palestrina
