cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Hierarchically modelling Kepler dwarfs and subgiants to improve inference of stellar properties with asteroseismology
Creators: name: Lyttle, Alexander J.
name: Davies, Guy R.
name: Li, Tanda
name: Carboneau, Lindsey M.
name: Leung, Ho-Hin
name: Westwood, Harry
name: Chaplin, William J.
name: Hall, Oliver J.
name: Huber, Daniel
name: Nielsen, Martin B.
name: Basu, Sarbani
name: García, Rafael A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: With recent advances in modelling stars using high-precision asteroseismology, the systematic effects associated with our assumptions of stellar helium abundance ($Y$) and the mixing-length theory parameter ($α_\mathrm{MLT}$) are becoming more important. We apply a new method to improve the inference of stellar parameters for a sample of Kepler dwarfs and subgiants across a narrow mass range ($0.8 < M < 1.2\,\mathrm{M_\odot}$). In this method, we include a statistical treatment of $Y$ and the $α_\mathrm{MLT}$. We develop a hierarchical Bayesian model to encode information about the distribution of $Y$ and $α_\mathrm{MLT}$ in the population, fitting a linear helium enrichment law including an intrinsic spread around this relation and normal distribution in $α_\mathrm{MLT}$. We test various levels of pooling parameters, with and without solar data as a calibrator. When including the Sun as a star, we find the gradient for the enrichment law, $ΔY / ΔZ = 1.05^{+0.28}_{-0.25}$ and the mean $α_\mathrm{MLT}$ in the population, $μ_α= 1.90^{+0.10}_{-0.09}$. While accounting for the uncertainty in $Y$ and $α_\mathrm{MLT}$, we are still able to report statistical uncertainties of 2.5 per cent in mass, 1.2 per cent in radius, and 12 per cent in age. Our method can also be applied to larger samples which will lead to improved constraints on both the population level inference and the star-by-star fundamental parameters.
description: 21 pages, 15 figures, 12 tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society
Additional file 3: of Activation of LXRɑ/β by cholesterol in malignant ascites promotes chemoresistance in ovarian cancer
Creators: name: Kim, Soochi
name: Lee, Maria
name: Dhanasekaran, Danny
name: Song, Yong
Publisher: name: figshare
Year: 2018
Subjects: Molecular Biology
Chemical Sciences not elsewhere classified
Biological Sciences not elsewhere classified
Mathematical Sciences not elsewhere classified
Cancer
Hematology

description: Table S2. Description of patients with malignant ascites (DOCX 12 kb)
Phenology and biometeorology of pine false webworm (Hymenoptera: Pamphiliidae) and its parasitoids in southern Ontario
Creators: name: Lyons, Donald Barry
Publisher: name: University of British Columbia
Year: 2010

description: Models of phenology of the pine false webworm (PFW), Acantholyda erythrocephala and one of its parasitoids were developed from relationships between PFW spatial distribution and microweather. Development of subterranean stages of PFW was simulated from rate-summation models developed from nonlinear regression equations describing the relationship between temperature and rate of development of post-diapause prepupae and pupae. Defoliation caused by PFW increased the soil's exposure to solar radiation resulting in higher soil temperatures and a corresponding reduction in development time of subterranean stages. Predictability was enhanced slightly when the distribution of insects and temperature of the soil were incorporated into the model. Increasing the time increment used in the model from 1 to 4 h did not adversely affect its resolution. Mating and oviposition of PFW occur within a few hours of emerging from the soil and the majority of PFW eggs were mature and ready for deposition at female emergence. Potential fecundity of PFW was accurately predicted from adult wet and dry weights. The oviposition pattern of PFW was also described by a model based on temperature-dependent oviposition and ageing rate functions. The effect of larval web construction on the development of arboreal stages was investigated. When exposed to sunlight, the web traps heat and raises the body temperature of its inhabitants. A model was developed and used to examine the significance of the web microclimate for development of larvae. Relationships between web temperatures, canopy temperatures and standard meteorological methods were developed to permit using data from standard weather stations to drive the model. Larval development increased by 1.4 to 2.8 d when estimated web temperatures were incorporated into the model, while development was retarded by 2.6 to 4.0 d when canopy temperatures were used instead of meteorological screen temperatures. Two ichneumonid parasitoids, Sinophorus megalodontis and an undescribed species of Olesicampe were reared from eonymphs of PFW. Morphological methods for distinguishing the immature stages of the parasitoids were developed. A predictive model for subterranean development and adult longevity of Olesicampe sp. was used to describe and to compare phenological observations from emergence traps, Malaise traps and dissections of host larvae. The effectiveness of the parasitoids as natural control agents is discussed in relation to host synchrony, encapsulation, and multi- and superparasitism.
A generalized Haus master equation model for mode-locked class-B lasers
Creators: name: Nizette, Michel
name: Vladimirov, Andrei G.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences
subject: 37N20, 78M34, 78M35

description: Using an asymptotic technique we develop a generalized version of class-B Haus partial differential equation mode-locking model that accounts for both the slow gain response to the averaged value of the field intensity and the fast gain dynamics on the scale comparable to the pulse duration. We show that unlike the conventional class-B Haus mode-locked model, our model is able to describe not only Q-switched instability of the fundamental mode-locked regime, but also the leading edge instability leading to harmonic mode-locked regimes with the increase of the pump power.
description: 14 pages, 5 figures
Implications of Compressed Supersymmetry for Collider and Dark Matter Searches
Creators: name: Baer, Howard
name: Box, Andrew
name: Park, Eun-Kyung
name: Tata, Xerxes
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Martin has proposed a scenario dubbed ``compressed supersymmetry'' (SUSY) where the MSSM is the effective field theory between energy scales M_{\rm weak} and M_{\rm GUT}, but with the GUT scale SU(3) gaugino mass M_3<< M_1 or M_2. As a result, squark and gluino masses are suppressed relative to slepton, chargino and neutralino masses, leading to a compressed sparticle mass spectrum, and where the dark matter relic density in the early universe may be dominantly governed by neutralino annihilation into ttbar pairs via exchange of a light top squark. We explore the dark matter and collider signals expected from compressed SUSY for two distinct model lines with differing assumptions about GUT scale gaugino mass parameters. For dark matter signals, the compressed squark spectrum leads to an enhancement in direct detection rates compared to models with unified gaugino masses. Meanwhile, neutralino halo annihilation rates to gamma rays and anti-matter are also enhanced relative to related scenarios with unified gaugino masses but, depending on the halo dark matter distribution, may yet be below the sensitivity of indirect searches underway. In the case of collider signals, we compare the rates for the potentially dominant decay modes of the stop_1 which may be expected to be produced in cascade decay chains at the LHC: \tst_1\to c\tz_1 and \tst_1\to bW\tz_1. We examine the extent to which multilepton signal rates are reduced when the two-body decay mode dominates. For the model lines that we examine here, the multi-lepton signals, though reduced, still remain observable at the LHC.
description: 22 pages including 24 eps figures
Viaggiando a ritroso nel tempo di una supernova
Creators: Laura Leonardi
Publisher: name: Media Inaf
Year: 2021

Un nuovo studio condotto dai ricercatori della Purdue University di West Lafayette ha riavvolto l’orologio di una supernova per calcolare l’età e il luogo d’origine dell’esplosione stellare. Le analisi sono basate sulle osservazioni di Hubble in luce visibile registrate nell’arco di dieci anni, e potrebbero aver individuato anche una stella di neutroni espulsa a seguito della catastrofica esplosione
Oxia Planum scolpita dai venti marziani
Creators: Ufficio stampa Inaf
Publisher: name: Media Inaf
Year: 2021

Acqua, ma anche forti venti hanno modellato le rocce e le dune di sabbia presenti nella regione marziana Oxia Planum, scelta quale sito di atterraggio della prossima missione euro-russa per lo studio del Pianeta rosso. A guidare lo studio, pubblicato sulla rivista Geophyiscal Research Letter, Simone Silvestro, ricercatore Inaf
Ecco la più completa mappa 3D delle “stelle fallite”
Creators: Giuseppe Fiasconaro
Publisher: name: Media Inaf
Year: 2021

Un team di internazionale di astronomi, coadiuvati dai volontari della collaborazione “Backyard Worlds: Planet 9” e dagli insegnanti e studenti del progetto Summer Research Connection, ha prodotto la più completa mappa 3D delle nane brune presenti nelle vicinanze del Sole. Riporta distanze e posizione di 525 nane brune, di cui 38 scoperte per la prima volta, situate fino a 65 anni luce dal Sole
Il progettista capo
Creators: Roberto Della Ceca
Publisher: name: Media Inaf
Year: 2021

Esattamente 55 anni fa, il 14 gennaio 1966, moriva l’ingegnere ucraino Sergej Pavlovič Korolëv, padre e artefice del programma spaziale sovietico. Un gigante del secolo passato, scrive Roberto Della Ceca, ricordando oggi su Media Inaf il suo contributo immenso alla storia umana delle attività spaziali
Bulletin de la Société internationale des amis de Montaigne. 2011-2, n° 54
Creators: name: (:Unap)
Publisher: name: Classiques Garnier
Year: 2011
Subjects: subject: Renaissance
subject: Philosophie et littérature
subject: Tradition et invention
subject: Culture classique
subject: Guerres de religion
subject: Diplomatie de l'esprit
subject: Éveil de la réflexion

description: Le Bulletin paraît deux fois par an et propose alternativement des numéros spéciaux (actes de colloque, contributions sur un thème spécifique) et des livraisons « généralistes » qui accueillent les participations individuelles autour du texte des Essais. Toutes les participations sont les bienvenues.
description: The Bulletin is published twice a year and offers alternately special issues (conference proceedings, contributions on a specific topic) and ones aimed at the more general reader.
Multi-party Private Set Operations with an External Decider
Creators: name: Ramezanian, Sara
name: Meskanen, Tommi
name: Niemi, Valtteri
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: A Private Set Operation (PSO) protocol involves at least two parties with their private input sets. The goal of the protocol is for the parties to learn the output of a set operation, i.e. set intersection, on their input sets, without revealing any information about the items that are not in the output set. Commonly, the outcome of the set operation is revealed to parties and no-one else. However, in many application areas of PSO the result of the set operation should be learned by an external participant whom does not have an input set. We call this participant the decider. In this paper, we present new variants of multi-party PSO, where there is a decider who gets the result. All parties expect the decider have a private set. Other parties neither learn this result, nor anything else about this protocol. Moreover, we present a generic solution to the problem of PSO.
Markov evolutions and hierarchical equations in the continuum I. One-component systems
Creators: name: Finkelshtein, Dmitri L.
name: Kondratiev, Yuri G.
name: Oliveira, Maria Joao
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: General birth-and-death as well as hopping stochastic dynamics of infinite particle systems in the continuum are considered. We derive corresponding evolution equations for correlation functions and generating functionals. General considerations are illustrated in a number of concrete examples of Markov evolutions appearing in applications.
description: 47 pages
Dissipative backward stochastic differential equations with locally Lipschitz nonlinearity
Creators: name: Confortola, Fulvia
Publisher: name: arXiv
Year: 2007
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: In this paper we study a class of backward stochastic differential equations (BSDEs) of the form dY(t)= -AY(t)dt -f_0(t,Y(t))dt -f_1(t,Y(t),Z(t))dt + Z(t)dW(t) on the interval [0,T], with given final condition at time T, in an infinite dimensional Hilbert space H. The unbounded operator A is sectorial and dissipative and the nonlinearity f_0(t,y) is dissipative and defined for y only taking values in a subspace of H. A typical example is provided by the so-called polynomial nonlinearities. Applications are given to stochastic partial differential equations and spin systems.
description: 22 pages
On some aspects of dynamics, modelling, and attitude analysis of satellites
Creators: name: Marandi, Said Rashed
Publisher: name: University of British Columbia
Year: 2010

description: The thesis identifies several limitations in the modelling and attitude stability analysis of two classes of spacecraft: rigid and flexible satellites. Attractive methods are proposed which promise to have far reaching consequences in spacecraft dynamics. These alternatives, developed based on techniques of differential equations, classical mechanics, and differential topology, are indicated below. (a) An Alternate Transition from the Lagrangian of a Satellite to Equations of Motion The classical procedure requires the Lagrangian to be expressed in terms of the corresponding generalized coordinates of the problem. This requirement significantly complicates the derivation of the equations of motion through an introduction of a set of librational generalized coordinates, which is strictly not a part of the dynamical system. Using the Lagrangian in the natural variables (angular velocity, direction cosines, and vibrational coordinates), one develops a procedure for derivation of equations of motion without an a priori choice of rotational generalized coordinates. For the case of a satellite with two flexible plate-type appendages, for example, the approach reduced the formulation time to one-third. (b) Synthesis and Depiction of Rotational Motion of Satellites and Robots The rotational coordinates in use for numerical prediction of orientation of a satellite are either singular or redundant. Furthermore, they lack a convenient visual interpretation. A new set of coordinates is proposed and an associated representation is developed which avoids these limitations. The procedure is applied to represent and integrate numerically the librational response of the flexible satellite mentioned in (a). (c) Resolution of Attitude Stability of Delp Satellites The development here tackles a long outstanding problem in the area of attitude stability of satellites. The resolution of this problem through normalization of the Hamiltonian leads to a better appreciation of stability associated with the class of gravity gradient structures such as the proposed Space Station.
Diffractive Optics for Gravitational Wave Detectors
Creators: name: Bunkowski, A.
name: Burmeister, O.
name: Danzmann, K.
name: Schnabel, R.
name: Clausnitzer, T.
name: Kley, E. -B.
name: Tünnermann, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: All-reflective interferometry based on nano-structured diffraction gratings offers new possibilities for gravitational wave detection. We investigate an all-reflective Fabry-Perot interferometer concept in 2nd order Littrow mount. The input-output relations for such a resonator are derived treating the grating coupler by means of a scattering matrix formalism. A low loss dielectric reflection grating has been designed and manufactured to test the properties of such a grating cavity.
A caccia di emissioni radio da Proxima Centauri
Creators: Ufficio stampa Inaf
Publisher: name: Media Inaf
Year: 2021

La recente campagna osservativa di Proxima Centauri, portata avanti dall’Istituto di astrofisica dell’Andalusia con la partecipazione dell’Inaf, apre una nuova strada per la caratterizzazione degli esopianeti e la ricerca delle condizioni per la vita extraterrestre. Dopo 17 giorni di osservazioni, i ricercatori hanno scoperto emissione aurorale radio dal sistema. I flussi radio osservati sono consistenti con emissione di maser di ciclotrone, e sono correlati alla posizione del pianeta Proxima b attorno alla stella
Axino warm dark matter and $Ω_b - Ω_{DM}$ coincidence
Creators: name: Seto, Osamu
name: Yamaguchi, Masahide
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We show that axinos, which are dominantly generated by the decay of the next-to-lightest supersymmetric particles produced from the leptonic $Q$-ball ($L$-ball), become warm dark matter suitable for the solution of the missing satellite problem and the cusp problem. In addition, $Ω_b - Ω_{DM}$ coincidence is naturally explained in this scenario.
description: 11 pages, no figure, typos corrected, references added, final version
On prospects for dark matter indirect detection in the Constrained MSSM
Creators: name: Roszkowski, Leszek
name: de Austri, Roberto Ruiz
name: Silk, Joe
name: Trotta, Roberto
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In the framework of the Constrained MSSM we derive the most probable ranges of the diffuse gamma radiation flux from the direction of the Galactic center and of the positron flux from the Galactic halo due to neutralino dark matter annihilation. We find that, for a given halo model, and assuming flat priors, the 68% probability range of the integrated gamma-ray flux spans about one order of magnitude, while the 95% probability range can be much larger and extend over four orders of magnitude (even exceeding five for a tiny region at small neutralino mass). The detectability of the signal by GLAST depending primarily on the cuspiness of the halo profile. The positron flux, on the other hand, appears to be too small to be detectable by PAMELA, unless the boost factor is at least of order ten and/or the halo profile is extremely cuspy. We also briefly discuss the sensitivity of our results to the choice of priors.
description: final PLB version, discussion of prior dependence added, paper based on a new software tool SuperBayeS (available from http://superbayes.org)
Decoherence in quantum cavities: Environmental erasure of carpet-type structures
Creators: name: Honrubia, E.
name: Sanz, A. S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Carpet-type structures constitute an ideal laboratory to study and analyze the robustness of the interference process that underlies this phenomenon against the harmful effects of decoherence. Here, without losing any generality, for simplicity, the case of a particle with a mass m is considered and described by a localized state corresponding to the ground state of a square box of width w, which is released inside a wider cavity (with a width L > w). The effects of decoherence are then numerically investigated by means of a simple dynamical model that captures the essential features of the phenomenon under Markovian conditions, leaving aside extra complications associated with a more detailed dynamical description of the system-environment interaction. As it is shown, this model takes into account and reproduces the fact that decoherence effects are stronger as energy levels become more separated (in energy), which translates into a progressive collapse of the energy density matrix to its main diagonal. However, because energy dissipation is not considered, an analogous behavior is not observed in the position representation, where a proper spatial localization of the probability density does not take place, but rather a delocalized distribution. This result emphasizes the fact that classicality is reached only if both decoherence and dissipation coexist; otherwise, non-classical traits might still persist. Actually, as it is also shown, in the position representation some off-diagonal correlations indeed survive unless an additional spatial-type factor is included in the model. This makes evident the rather complex nature of the decoherence phenomenon and hence the importance to have a familiarity with how it manifests in different representations, particularly with the purpose to determine and design reliable control mechanisms.
description: 18 pages, 11 figures
Svelata la doppia origine della polvere cosmica
Creators: Redazione Sissa
Publisher: name: Media Inaf
Year: 2021

Da un team internazionale di ricercatori guidato da Darko Donevski della Sissa arriva un nuovo metodo per lo studio delle grandi galassie massicce e polverose dell’universo lontano che fa luce sui processi fisici responsabili per la formazione di polvere in questi giganti
A unified approach to SIC-POVMs and MUBs
Creators: name: Albouy, O.
name: Kibler, M. R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: A unified approach to (symmetric informationally complete) positive operator valued measures and mutually unbiased bases is developed in this article. The approach is based on the use of operator equivalents expanded in the enveloping algebra of SU(2). Emphasis is put on similarities and differences between SIC-POVMs and MUBs.
description: 15 pages
Gli archi che disegnano il cielo del Nord
Creators: Eleonora Ferroni
Publisher: name: Media Inaf
Year: 2021

Giulio Cobianchi, da sempre appassionato di paesaggi e avventure, è riuscito ad affascinare la Nasa con una fotografia della Via Lattea e dell’aurora boreale. L'immagine è in realtà composta da 18 scatti acquisiti a metà dicembre 2020 in Norvegia, dove Cobianchi vive con la moglie. Lo abbiamo intervistato
Sbranata da un buco nero, un morso ogni 114 giorni
Creators: Marco Malaspina
Publisher: name: Media Inaf
Year: 2021

Un’esplosione d’energia che si ripete a intervalli regolari – circa tre volte all’anno, sotto l’occhio di telescopi a terra e nello spazio – ha convinto un team di astrofisici che all’origine del fenomeno chiamato Asassn-14ko, in una galassia a 570 milioni di anni luce da noi, vi sia un evento ripetuto di distruzione mareale
Visibilité Et Impact Scientifique Entre Réalité Et Illusion
Creators: name: Jaber, Jamila
Publisher: name: Zenodo
Year: 2019
Subjects: ,open access ,visibilité scientifique ,impact ,pays arabes ,système de communication scientifique ,edition scientifique ,hégémonie ,impérialisme ,facteur d'impact ,scientométrie ,libre accès ,plan s

description: L'Impact de l'Adoption de l’Open Access par la Communauté Scientifique Arabe par rapport à la visibilité et l'impact scientifique ainsi que les enjeux de l'edition scientifique
Coupling of a Single Tin-vacancy Center to a Photonic Crystal Cavity in Diamond
Creators: name: Kuruma, Kazuhiro
name: Pingault, Benjamin
name: Chia, Cleaven
name: Renaud, Dylan
name: Hoffmann, Patrick
name: Iwamoto, Satoshi
name: Ronning, Carsten
name: Lončar, Marko
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: We demonstrate optical coupling between a single tin-vacancy (SnV) center in diamond and a free-standing photonic crystal nanobeam cavity. The cavities are fabricated using quasi-isotropic etching and feature experimentally measured quality factors as high as ~11,000. We investigate the dependence of a single SnV center's emission by controlling the cavity wavelength using a laser-induced gas desorption technique. Under resonance conditions, we observe an intensity enhancement of the SnV emission by a factor of 12 and a 16-fold reduction of the SnV lifetime. Based on the large enhancement of the SnV emission rate inside the cavity, we estimate the Purcell factor for the SnV zero-phonon line to be 37 and the coupling efficiency of the SnV center to the cavity, the beta factor, to be 95%. Our work paves the way for the realization of quantum photonic devices and systems based on efficient photonic interfaces using the SnV color center in diamond.
Koi-5Ab, il pianeta con tre Soli
Creators: Maura Sandri
Publisher: name: Media Inaf
Year: 2021

Dopo una lunga caccia durata molti anni, che ha visto coinvolti due telescopi spaziali – Kepler e Tess – e diversi telescopi terrestri, finalmente è stata confermata l’esistenza di Koi-5Ab, un pianeta simile a uno dei nostri giganti gassosi, come Giove o Saturno, e appartenente a un sistema triplo piuttosto insolito
An analysis of the fluctuations of the geomagnetic dipole
Creators: name: Brendel, K.
name: Kuipers, J.
name: Barkema, G. T.
name: Hoyng, P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: The time evolution of the strength of the Earth's virtual axial dipole moment (VADM) is analyzed by relating it to the Fokker-Planck equation, which describes a random walk with VADM-dependent drift and diffusion coefficients. We demonstrate first that our method is able to retrieve the correct shape of the drift and diffusion coefficients from a time series generated by a test model. Analysis of the Sint-2000 data shows that the geomagnetic dipole mode has a linear growth time of 13 to 33 kyr, and that the nonlinear quenching of the growth rate follows a quadratic function of the type [1-(x/x0)^2]. On theoretical grounds, the diffusive motion of the VADM is expected to be driven by multiplicative noise, and the corresponding diffusion coefficient to scale quadratically with dipole strength. However, analysis of the Sint-2000 VADM data reveals a diffusion which depends only very weakly on the dipole strength. This may indicate that the magnetic field quenches the amplitude of the turbulent velocity in the Earth's outer core.
description: 11 pages, 6 figures
Lampo gamma svela i segreti delle magnetar
Creators: Ufficio stampa Inaf
Publisher: name: Media Inaf
Year: 2021

C’è una magnetar – una stella di neutroni dal campo magnetico estremamente intenso – all’origine di un breve ma brillantissimo lampo gamma osservato lo scorso aprile da diversi telescopi spaziali, tra cui Integral dell’Agenzia spaziale europea e Fermi della Nasa. Si tratta del terzo lampo gamma associato al brillamento gigante di una magnetar, e di quello meglio localizzato: nel cuore della galassia dello Scultore, a 11,5 milioni di anni luce da noi
Stable oscillations of a predator-prey probabilistic cellular automaton: a mean-field approach
Creators: name: Tomé, Tânia
name: de Carvalho, Kelly C
Publisher: name: arXiv
Year: 2007
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We analyze a probabilistic cellular automaton describing the dynamics of coexistence of a predator-prey system. The individuals of each species are localized over the sites of a lattice and the local stochastic updating rules are inspired on the processes of the Lotka-Volterra model. Two levels of mean-field approximations are set up. The simple approximation is equivalent to an extended patch model, a simple metapopulation model with patches colonized by prey, patches colonized by predators and empty patches. This approximation is capable of describing the limited available space for species occupancy. The pair approximation is moreover able to describe two types of coexistence of prey and predators: one where population densities are constant in time and another displaying self-sustained time-oscillations of the population densities. The oscillations are associated with limit cycles and arise through a Hopf bifurcation. They are stable against changes in the initial conditions and, in this sense, they differ from the Lotka-Volterra cycles which depend on initial conditions. In this respect, the present model is biologically more realistic than the Lotka-Volterra model.
description: 10 figures
Fondo d’onde gravitazionali nel polso delle pulsar
Creators: Giuseppe Fiasconaro
Publisher: name: Media Inaf
Year: 2021

Un team internazionale di ricercatori ha rilevato un segnale, nel set di dati ottenuti dalle osservazioni decennali di diverse pulsar, indicativo del cambiamento del timing di pulsazione di questi oggetti. Una perturbazione che potrebbe essere dovuta al fondo di onde gravitazionali.  Tutti i dettagli su The Astrophysical Journal Letters
Estesa al 2025 la missione della Nasa Juno
Creators: Ufficio stampa Inaf
Publisher: name: Media Inaf
Year: 2021

La sonda ci farà scoprire ulteriori segreti di Giove per altri cinque anni, grazie anche ai contributi italiani di Jiram, capace di raccogliere sia immagini che spettrogrammi, e KaT, che permette la misura della gravità del pianeta tramite l’effetto Doppler di un segnale a microonde
Kinematical Studies of the Low Mass X-Ray Binary GR Mus (XB1254-690)
Creators: name: Barnes, A. D.
name: Casares, J.
name: Cornelisse, R.
name: Charles, P. A.
name: Steeghs, D.
name: Hynes, R. I.
name: O'Brien, K.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present simultaneous high-resolution optical spectroscopy and X-ray data of the X-ray binary system GR Mus (XB1254-690), obtained over a full range of orbital phases. The X-ray observations are used to re-establish the orbital ephemeris for this source. The optical data includes the first spectroscopic detection of the donor star in this system, through the use of the Doppler Tomography technique on the Bowen fluorescence blend (~4630-4650 A). In combination with an estimate for the orbital parameters of the compact object using the wings of the He II 4686 emission line, dynamical mass constraints of 1.20 < M_X/M_{sun} < 2.64 for the neutron star and 0.45 < M_2/M_{sun} < 0.85 for the companion are derived.
description: 10 pages, 14 figures, accepted for publication in MNRAS
Il lato oscuro della Galassia svelato dalle pulsar
Creators: Maura Sandri
Publisher: name: Media Inaf
Year: 2021

Grazie ai dati sulle pulsar forniti da collaborazioni internazionali tra cui NanoGrav, è stato possibile determinare le accelerazioni radiali e verticali delle stelle all’interno della Via Lattea. Da queste, conoscendo anche la quantità di materia visibile nella nostra galassia, i ricercatori sono poi stati in grado di calcolare la densità della materia oscura nella Via Lattea senza assumere che essa si trovi in uno stato stazionario. Lo studio verrà pubblicato su ApJ Letters
A oltre 13 miliardi di anni luce il quasar più lontano
Creators: Valentina Guglielmo
Publisher: name: Media Inaf
Year: 2021

Ecco il nuovo quasar più antico dell’universo, il più distante. Un mostro cosmico alimentato da un buco nero supermassiccio – oltre 1.6 miliardi di volte più massiccio del Sole e oltre mille volte più luminoso della nostra intera galassia – che sta inghiottendo l’equivalente in massa di 25 Soli ogni anno. Tutti i dettagli su ApJ Letters
Là dove Cerere è più blu
Creators: Marco Galliani
Publisher: name: Media Inaf
Year: 2021

Perché alcune regioni in corrispondenza dei crateri di recente formazione su Cerere presentano un’anomala colorazione bluastra? Una possibile risposta a questa domanda che tempo arrovella i planetologi la fornisce lo studio pubblicato su Nature Communications e realizzato da un team che vede la partecipazione di ricercatrici e ricercatori dell’Inaf
Fusioni stellari. Episodi I, II e III
Creators: Marco Malaspina
Publisher: name: Media Inaf
Year: 2021

Cosa succede quando due stelle di neutroni – o un buco nero e una stella di neutroni – si fondono? Per ricostruire il processo in dettaglio, un team internazionale fondato da Stefano Covino dell’Inaf di Brera ha studiato l’emissione di luce polarizzata dalle kilonove prodotte durante questi eventi. I risultati sono pubblicati in tre articoli, l’ultimo dei quali uscito ora su Monthly Notices of the Royal Astronomical Society
Un innocuo asteroide
Creators: Albino Carbognani
Publisher: name: Media Inaf
Year: 2021

L’asteroide near-Earth 2009 JF1, un oggetto con diametro compreso fra i 7 e i 24 metri, ha una remota probabilità di colpire la Terra il 6 maggio 2022. Anche nello scenario peggiore, però, non costituisce un pericolo per il nostro pianeta. Vediamo perché
Galassie: chi si fonde, si spegne
Creators: Ufficio stampa Inaf
Publisher: name: Media Inaf
Year: 2021

Uno studio condotto con Alma suggerisce che la causa fondamentale dello spegnimento della formazione stellare in galassie massicce nell’universo lontano sarebbe la fusione tra galassie. L’evento di fusione innescherebbe una fuga di gas molecolare – il combustibile insostituibile per la formazione di nuove stelle – nello spazio circostante e, qualora accompagnato da un evento di massiccia formazione stellare al centro della galassia fusa, darebbe vita alle enormi galassie che non producono più stelle, dal tipico colore rosso, la cui origine è tuttora dibattuta fra gli esperti
SDSS J233325.92+152222.1 and the evolution of intermediate polars
Creators: name: Southworth, John
name: Gaensicke, B. T.
name: Marsh, T. R.
name: de Martino, D.
name: Aungwerojwit, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Intermediate polars (IPs) are cataclysmic variables which contain magnetic white dwarfs with a rotational period shorter than the binary orbital period. Evolutionary theory predicts that IPs with long orbital periods evolve through the 2-3 hour period gap, but it is very uncertain what the properties of the resulting objects are. Whilst a relatively large number of long-period IPs are known, very few of these have short orbital periods. We present phase-resolved spectroscopy and photometry of SDSS J233325.92+152222.1 and classify it as the IP with the shortest known orbital period (83.12 +/- 0.09 min), which contains a white dwarf with a relatively long spin period (41.66 +/- 0.13 min). We estimate the white dwarf's magnetic moment to be mu(WD) \approx 2 x 10^33 G cm^3, which is not only similar to three of the other four confirmed short-period IPs but also to those of many of the long-period IPs. We suggest that long-period IPs conserve their magnetic moment as they evolve towards shorter orbital periods. Therefore the dominant population of long-period IPs, which have white dwarf spin periods roughly ten times shorter than their orbital periods, will likely end up as short-period IPs like SDSS J2333, with spin periods a large fraction of their orbital periods.
description: 6 pages with 5 figures, accepted for publication in MNRAS
Physicochemical and cytotoxicity analysis of green synthesis carbon dots for cell imaging
Creators: name: Fatahi, Zahra
name: Esfandiari, Neda
name: Ehtesabi, Hamide
name: Bagheri, Zeinab
name: Tavana, Hossein
name: Ranjbar, Zahra
name: Latifi, Hamid
Publisher: name: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund
Year: 2019
Subjects: carbon dots
bitter orange
imaging
cytotoxicity

description: Carbon dots (CDs) have outstanding optical properties, biocompatibility, and photostability, making them attractive for imaging applications. A facile and green one-step hydrothermal synthesis method is proposed, which can be safely used in a wide range of applications such as chemical sensing, bioimaging, and optoelectronics. In this study, we report green synthesis of carbon dots from bitter orange juice (Citrus Aurantium) by hydrothermal treatment for the first time. We studied effects of time, temperature, and pH on fluorescence of CDs, characterized them using various spectroscopic and microscopic methods, and evaluated their toxicity to different cell lines. Identifying an optimum reaction condition of 180 ºC for 7 h heating gave CDs that showed pH-dependent fluorescence, with the largest fluorescence at a pH of 7.0. The CDs were 1-2 nm in size with a spherical morphology and negative surface charge. The CDs showed a high quantum yield of 19.9 %, reasonable photostability, excellent water solubility, and long fluorescence lifetime. A one step hydrothermal rout led to various hydrophilic functional groups on the surface of the CDs. Our results showed that the CDs were non-toxic over a large concentration range and effective for imaging of cells, indicating their potential as imaging probes in medical diagnostics and biosensor applications.
description: EXCLI Journal; 18:Doc454; ISSN 1611-2156
Parasite common envelope evolution by triple-star systems
Creators: name: Soker, Noam
name: Bear, Ealeal
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We study a scenario by which a giant wide tertiary star engulfs and forces a tight binary system of a white dwarf (WD) and a main sequence (MS) star to enter a common envelope evolution (CEE) with each other, and then unbinds the WD-MS common envelope. The WD-MS binary system, now with the WD inside the MS envelope, does not have sufficient orbital energy to unbind their common envelope. However, as they approach the center of the giant star Roche lobe overflow to the core of the giant star and/or merger of the WD with the core remove a large fraction of the WD-MS common envelope or all of it. Namely, the energy source for unbinding the WD-MS tight common envelope is the triple-star CEE. For that we term this scenario a parasite CEE. Overall, the destruction of the MS star absorbs energy from the triple-star system, a process that might lead to WD-core merger during the triple-star CEE. The parasite CEE leaves behind either one massive WD that in some cases might explode as a peculiar type Ia supernova or two close WDs that at later time might explode as a type Ia supernova. We very crudely estimate the rate of the parasite CEE to be a fraction of ~0.001 out of all evolved triple stars.
description: Accepted for publication in MNRAS
Input-output relations for a 3-port grating coupled Fabry-Perot cavity
Creators: name: Bunkowski, A.
name: Burmeister, O.
name: Danzmann, K.
name: Schnabel, R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We analyze an optical 3-port reflection grating by means of a scattering matrix formalism. Amplitude and phase relations between the 3 ports, i.e. the 3 orders of diffraction are derived. Such a grating can be used as an all-reflective, low-loss coupler to Fabry-Perot cavities. We derive the input output relations of a 3-port grating coupled cavity and find distinct properties not present in 2-port coupled cavities. The cavity relations further reveal that the 3-port coupler can be designed such that the additional cavity port interferes destructively. In this case the all-reflective, low-loss, single-ended Fabry-Perot cavity becomes equivalent to a standard transmissive, 2-port coupled cavity.
All local conserved quantities of the XXZ model
Creators: name: Nienhuis, Bernard
name: Huijgen, Onno E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mathematical Physics (math-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Integrability of the XXZ model induces an extensive number of conserved quantities. In this paper we give a closed form expression for the series of local conserved charges of the XXZ model on a closed chain with or without a twist. We prove that each element of the series commutes with the Hamiltonian.
description: 26 pages, 4 figures, submitted to J. Phys. A: Math. Theor
Complexity Considerations, cSAT Lower Bound
Creators: name: Hofman, Radoslaw
Publisher: name: arXiv
Year: 2007
Subjects: subject: Logic (math.LO)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 68Q15, 68Q17, 03D15, 68Q19

description: This article discusses completeness of Boolean Algebra as First Order Theory in Goedel's meaning. If Theory is complete then any possible transformation is equivalent to some transformation using axioms, predicates etc. defined for this theory. If formula is to be proved (or disproved) then it has to be reduced to axioms. If every transformation is deducible then also optimal transformation is deducible. If every transformation is exponential then optimal one is too, what allows to define lower bound for discussed problem to be exponential (outside P). Then we show algorithm for NDTM solving the same problem in O(n^c) (so problem is in NP), what proves that P \neq NP. Article proves also that result of relativisation of P=NP question and oracle shown by Baker-Gill-Solovay distinguish between deterministic and non-deterministic calculation models. If there exists oracle A for which P^A=NP^A then A consists of infinite number of algorithms, DTMs, axioms and predicates, or like NDTM infinite number of simultaneous states.
description: Presented at IMECS2007, presentation is avaliable here: http://www.teycom.pl/docs/ICCS_160_prez.pdf Awarded with Certificate of Merit for International Conference on Computer Science 2007 (ICCS2007)
The C$^{18}$O core mass function toward Orion A: Single-dish observations
Creators: name: Takemura, Hideaki
name: Nakamura, Fumitaka
name: Ishii, Shun
name: Shimajiri, Yoshito
name: Sanhueza, Patricio
name: Tsukagoshi, Takashi
name: Kawabe, Ryohei
name: Hirota, Tomoya
name: Kataoka, Akimasa
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We have performed an unbiased dense core survey toward the Orion A Giant Molecular Cloud in the C$^{18}$O ($J$=1--0) emission line taken with the Nobeyama Radio Observatory (NRO) 45-m telescope. The effective angular resolution of the map is 26", which corresponds to $\sim$ 0.05 pc at a distance of 414 pc. By using the Herschel-Planck H$_2$ column density map, we calculate the C$^{18}$O fractional abundance and find that it is roughly constant over the column density range of $\lesssim$ 5 $\times$ 10$^{22}$ cm$^{-3}$, although a trend of C$^{18}$O depletion is determined toward higher column density. Therefore, C$^{18}$O intensity can follow the cloud structure reasonably well. The mean C$^{18}$O abundance in Orion A is estimated to be 5.7$\times$10$^{-7}$, which is about 3 times larger than the fiducial value. We identified 746 C$^{18}$O cores with astrodendro and classified 709 cores as starless cores. We compute the core masses by decomposing the Herschel-Planck dust column density using the relative proportions of the C$^{18}$O integrated intensities of line-of-sight components. Applying this procedure, we attempt to remove the contribution of the background emission, i.e., the ambient gas outside the cores. Then, we derived mass function for starless cores and found that it resembles the stellar initial mass function (IMF). The CMF for starless cores, $dN/dM$, is fitted with a power-law relation of $M^α$ with a power index of $α= -$2.25$\pm$ 0.16 at the high-mass slope ($\gtrsim$ 0.44 $M_\odot$). We also found that the ratio of each core mass to the total mass integrated along the line of sight is significantly large. Therefore, in the previous studies, the core masses derived from the dust image are likely to be overestimated at least by a factor of a few. Accordingly, such previous studies may underestimate the star formation efficiency of individual cores.
description: 66 pages, 15 figures, accepted by PASJ
$O(d,d)$ symmetry in teleparallel dark energy
Creators: name: Paliathanasis, Andronikos
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: An important characteristic of the Dilaton cosmological model is the Gasperini-Veneziano duality transformation which follows from the existence of the $O\left( d,d\right) $ symmetry. In this study, we consider the equivalent Dilaton theory in teleparallel dark energy with the $O\left( d,d\right) $ symmetry, while the equivalent teleparallel-duality transformation is presented. The classical solution of the field equations is derived. Finally the Wheeler-DeWitt equation of quantum cosmology is discussed.
description: 10 pages, no figures, version accepted for publication in the European Physical Journal Plus
The importance of thermal disorder and electronic occupation for the T-dependence of the optical conductivity in FeSi and MnSi
Creators: name: Jarlborg, T.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The spectral weight (SW) for optical transitions in FeSi and MnSi are calculated as function of temperature by means of LMTO-LDA band calculations. The main effects, caused by structural disorder and electronic Fermi-Dirac distribution, act oppositely on the T-dependence of the SW, while the variation of the magnetic moment in MnSi has only a minor effect. The calculations agree with the experimental findings of an increasing SW in FeSi and a decreasing SW in MnSi as function of T. The results can be understood from the change of the bandstructure with disorder.
description: (5 pages, 4 figures)