Miracle-dz/UniFAR-FTUs huggingface dataset:
Spiral eigenmodes triggered by grooves in the phase space of disc galaxies

We use linear perturbation theory to investigate how a groove in the phase space of a disc galaxy changes the stellar disc's stability properties. Such a groove is a narrow trough around a fixed angular momentum from which most stars have been removed, rendering part of the disc unresponsive to spiral waves. We find that a groove can dramatically alter a disc's eigenmode spectrum by giving rise to a set of vigorously growing eigenmodes. These eigenmodes are particular to the grooved disc and are absent from the original ungrooved disc'smode spectrum. We discuss the properties and possible origin of the different families of new modes. By the very nature of our technique, we prove that a narrow phase-space groove can be a source of rapidly growing spiral patterns that are true eigenmodes of the grooved disc and that no non-linear processes need to be invoked to explain their presence in N-body simulations of disc galaxies. Our results lend support to the idea that spiral structure can be a recurrent phenomenon, in which one generation of spiral modes alters a disc galaxy's phase space in such a way that a following generation of modes is destabilized.
HIGH SPECTRAL RESOLUTION MEASUREMENT OF THE SUNYAEV–ZEL'DOVICH EFFECT NULL WITH Z-Spec

The Sunyaev–Zel'dovich (SZ) effect spectrum crosses through a null where ΔTCMB = 0 near ν0 = 217 GHz. In a cluster of galaxies, ν0 can be shifted from the canonical thermal SZ effect value by corrections to the SZ effect scattering due to the properties of the inter-cluster medium. We have measured the SZ effect in the hot galaxy cluster RX J 1347.5 − 1145 with Z-Spec, an R ∼ 300 grating spectrometer sensitive between 185 and 305 GHz. These data comprise a high spectral resolution measurement around the null of the SZ effect and clearly exhibit the transition from negative to positive ΔTCMB over the Z-Spec band. The SZ null position is measured to be ν0 = 225.8 ± 2.5(stat.) ± 1.2(sys.) GHz, which differs from the canonical null frequency by 3. 0σ and is evidence for modifications to the canonical thermal SZ effect shape. Assuming the measured shift in ν0 is due only to relativistic corrections to the SZ spectrum, we place the limit kTe = 17.1 ± 5.3 keV from the zero-point measurement alone. By simulating the response of the instrument to the sky, we are able to generate likelihood functions in {y0, Te, vpec} space. For vpec = 0 km s−1, we measure the best-fitting SZ model to be y0 = 4.6+0.6 − 0.9 × 10−4, Te, 0 = 15.2+12 − 7.4 keV. When vpec is allowed to vary, a most probable value of vpec = + 450 ± 810 km s−1 is found.
Local temperatures and local terms in modular Hamiltonians

We show there are analogues to the Unruh temperature that can be defined for any quantum field theory and region of the space. These local temperatures are defined using relative entropy with localized excitations. We show important restrictions arise from relative entropy inequalities and causal propagation between Cauchy surfaces. These suggest a large amount of universality for local temperatures, specially the ones affecting null directions. For regions with any number of intervals in two space-time dimensions the local temperatures might arise from a term in the modular Hamiltonian proportional to the stress tensor. We argue this term might be universal, with a coefficient that is the same for any theory, and check analytically and numerically this is the case for free massive scalar and Dirac fields. In dimensions $d\ge 3$ the local terms in the modular Hamiltonian producing these local temperatures cannot be formed exclusively from the stress tensor. For a free scalar field we classify the structure of the local terms.
Chalcogen Bond as a Factor Stabilizing Ligand Conformation in the Binding Pocket of Carbonic Anhydrase IX Receptor Mimic

It is postulated that the overexpression of Carbonic Anhydrase isozyme IX in some cancers contributes to the acidification of the extracellular matrix. It was proved that this promotes the growth and metastasis of the tumor. These observations have made Carbonic Anhydrase IX an attractive drug target. In the light of the findings and importance of the glycoprotein in the cancer treatment, we have employed quantum–chemical approaches to study non-covalent interactions in the binding pocket. As a ligand, the acetazolamide (AZM) molecule was chosen, being known as a potential inhibitor exhibiting anticancer properties. First-Principles Molecular Dynamics was performed to study the chalcogen and other non-covalent interactions in the AZM ligand and its complexes with amino acids forming the binding site. Based on Density Functional Theory (DFT) and post-Hartree–Fock methods, the metric and electronic structure parameters were described. The Non-Covalent Interaction (NCI) index and Atoms in Molecules (AIM) methods were applied for qualitative/quantitative analyses of the non-covalent interactions. Finally, the AZM–binding pocket interaction energy decomposition was carried out. Chalcogen bonding in the AZM molecule is an important factor stabilizing the preferred conformation. Free energy mapping via metadynamics and Path Integral molecular dynamics confirmed the significance of the chalcogen bond in structuring the conformational flexibility of the systems. The developed models are useful in the design of new inhibitors with desired pharmacological properties.
Hubble Space Telescope survey of the Perseus cluster – IV. Compact stellar systems in the Perseus cluster core and ultracompact dwarf formation in star-forming filaments

We present the results of the first search for ultracompact dwarfs (UCDs) in the Perseus cluster core, including the region of the cluster around the unusual brightest cluster galaxy NGC 1275. Utilizing Hubble Space Telescope Advanced Camera for Surveys imaging, we identify a sample of 84 UCD candidates with half-light radii 10 < re < 57 pc out to a distance of 250 kpc from the cluster centre, covering a total survey area of ∼70 arcmin2. All UCDs in Perseus lie in the same size–luminosity locus seen for confirmed UCDs in other regions of the local Universe. The majority of UCDs are brighter than MR=−10.5, and lie on an extrapolation of the red sequence followed by the Perseus cluster dwarf elliptical population to fainter magnitudes. However, three UCD candidates in the vicinity of NGC 1275 are very blue, with colours (B−R)0 < 0.6 implying a cessation of star formation within the past 100 Myr. Furthermore, large blue star clusters embedded in the star-forming filaments are highly indicative that both proto-globular clusters (GCs) and proto-UCDs are actively forming at the present day in Perseus. We therefore suggest star-forming filaments as a formation site for some UCDs, with searches necessary in other low-redshift analogues of NGC 1275 necessary to test this hypothesis. We also suggest that tidal disruption of dwarf galaxies is another formation channel for UCD formation in the core of Perseus as tidal disruption is ongoing in this region as evidenced by shells around NGC 1275. Finally, UCDs may simply be massive GCs based on strong similarities in the colour trends of the two populations.
Phase diagram description of the CaCu3Fe4O12 double perovskite

CaCu$_3$Fe$_4$O$_{12}$ exhibits a temperature-induced transition from a ferrimagnetic-insulating phase, in which Fe appears charge disproportionated, as Fe$^{3+}$ and Fe$^{5+}$, to a paramagnetic-metallic phase at temperatures above 210 K, with Fe$^{4+}$ present. To describe it, we propose a microscopic effective model with two interpenetrating sublattices of Fe$^{(4-\delta)+}$ and Fe$^{(4+\delta)+}$, respectively, being $\delta$ the Fe-charge disproportionation. We include all $3d$-Fe orbitals: $t_{2g}$ localized orbitals, with spin 3/2 and magnetically coupled, plus two degenerate itinerant $e_g$ orbitals with local and nearest-neighbor (NN) electron correlations, and hopping between NN $e_g$ orbitals of the same symmetry. Allub and Alascio previously proposed a model to describe the phase transition in LaCu$_3$Fe$_4$O$_{12}$ from a paramagnetic-metal to an antiferromagnetic-insulator, induced by temperature or pressure, involving charge transfer between Fe and Cu ions, in contrast to Fe-charge disproportionation. With the model proposed for CaCu$_3$Fe$_4$O$_{12}$, modified to account for this difference between the two compounds, the density of states of the itinerant Fe orbitals was obtained, using Green's functions methods. The phase diagram for CaCu$_3$Fe$_4$O$_{12}$ was calculated, including phases exhibiting Fe-charge disproportionation, where the two eg orbitals in each site are symmetrically occupied, as well as novel phases exhibiting local orbital selectivity/asymmetric occupation of $e_g$ orbitals. Both kinds of phases may exhibit paramagnetism and ferromagnetism. We determined the model parameters which best describe the phase transition observed in CaCu$_3$Fe$_4$O$_{12}$, and found other phases at different parameter ranges, which might be relevant for other compounds of the ACu$_3$Fe$_4$O$_{12}$ family, which present both types of transitions.
Electron-phonon coupling and the charge gap of spin-density wave iron-pnictide materials from quasiparticle relaxation dynamics

We investigate the quasiparticle relaxation and low-energy electronic structure in undoped SrFe_2As_2 exhibiting spin-density wave (SDW) ordering using optical pump-probe femtosecond spectroscopy. A remarkable critical slowing down of the quasiparticle relaxation dynamics at the SDW transition temperature T_SDW = 200K is observed. From temperature dependence of the transient reflectivity amplitude we determine the SDW-state charge gap magnitude, 2Delta_SDW/k_BT_SDW=7.2+-1. The second moment of the Eliashberg function, lambda =110+-10meV^2, determined from the relaxation time above T_SDW, is similar to SmFeAsO and BaFe_2As_2 indicating a rather small electron phonon coupling constant unless the electron-phonon spectral function (alpha^2F(omega) is strongly enhanced in the low-energy phonon region.
The GTC exoplanet transit spectroscopy survey - I. OSIRIS transmission spectroscopy of the short period planet WASP-43b

Aims. In this work, we use long-slit spectroscopy observations of a transit event of the close-in orbiting planet WASP-43b (Mp = 2:034 MJup, Rp = 1:036 RJup) in an e ort to detect its atmosphere. Methods. We used the Gran Telescopio Canarias (GTC) instrument OSIRIS to obtain long-slit spectra in the optical range 520‐1040 nm of the planetary host star WASP-43 and of a reference star during a full primary transit event and four partial transit observations. We integrated the stellar flux of both stars in di erent wavelength regions producing several light curves. We fitted transit models to these curves to measure the star-to-planet radius ratio, Rp=Rs, across wavelength among other physical parameters. Results. We measure a mean planet-to-star radius ratio in the white light curve of 0:15988 +0:00133 0:00145. Using broadband filters, we detect the color signature of WASP-43. We present a tentative detection in the planet-to-star radius ratio around the Nai doublet ( 588.9, 589.5 nm) when compared to the nearby continuum at the 2.9 level. We find no significant excess of the measured planet-to-star radius ratio around the Ki doublet ( 766.5 nm, 769.9 nm) when compared to the nearby continuum. Combining our observations with previously published epochs, we refine the estimation of the orbital period. Using a linear ephemeris, we obtained a period of P = 0:81347385 1:5 10 7 days. Using a quadratic ephemeris, we obtained an orbital period of 0:81347688 8:6 10 7 days, and a change in this parameter of ˙ P = 0:15 0:06 s/year. As previous results, this hints to the orbital decay of this planet although a timing analysis over several years needs to be made to confirm this.
Gravitational redshift, equivalence principle, and matter waves

We review matter wave and clock comparison tests of the gravitational redshift. To elucidate their relationship to tests of the universality of free fall (UFF), we define scenarios wherein redshift violations are coupled to ("type II"), or independent of ("type III"), violations of UFF, respectively. Clock comparisons and atom interferometers are sensitive to similar effects in both scenarios.
Quasinormal modes and van der Waals-like phase transition of charged AdS black holes in Lorentz symmetry breaking massive gravity

Using the quasinormal modes of a massless scalar perturbation, we investigate the small/large black hole phase transition in the Lorentz symmetry breaking massive gravity. We mainly focus on two issues: (i) the sign change of slope of the quasinormal mode frequencies in the complex-[Formula: see text] diagram; (ii) the behaviors of the imaginary part of the quasinormal mode frequencies along the isobaric or isothermal processes. For the first issue, our result shows that, at low fixed temperature or pressure, the phase transition can be probed by the sign change of slope. While increasing the temperature or pressure to certain values near the critical point, there will appear the deflection point, which indicates that such method may not be appropriate to test the phase transition. In particular, the behavior of the quasinormal mode frequencies for the small and large black holes tend to be the same at the critical point. For the second issue, it is shown that the nonmonotonic behavior is observed only when the small/large black hole phase transition occurs. Therefore, this property can provide us with an additional method to probe the phase transition through the quasinormal modes.
EQUIVALENCE BETWEEN PALATINI AND METRIC FORMALISMS OF f(R)-GRAVITY BY DIVERGENCE-FREE CURRENT

The equivalence between metric and Palatini formalisms in f(R)-gravity can be achieved in the general context of theories with divergence-free current. This equivalence is a necessary result of a symmetry which is included in a particular conservation equation of the current. In fact the conservation equation, by an appropriate redefinition of the introduced auxiliary field, may be encoded in a massless scalar field equation.
Comment on "An arbitrated quantum signature scheme with fast signing and verifying"

Recently, Liu et al. (Quantum Inf Process (2014) 13:491-502) proposed an arbitrated quantum signature (AQS) scheme, where a signature receiver (Bob) can verify the signer's signature through the help of a trusted arbitrator. However, this paper shows that a malicious Bob can perform the existential forgery of the signature under the chosen message attack without being detected.
SOFIA INFRARED SPECTROPHOTOMETRY OF COMET C/2012 K1 (PAN-STARRS)

We present pre-perihelion infrared 8–31 μm spectrophotometric and imaging observations of comet C/2012 K1 (Pan-STARRS), a dynamically new Oort Cloud comet, conducted with NASA's Stratospheric Observatory for Infrared Astronomy facility (+FORCAST) in 2014 June. As a “new” comet (first inner solar system passage), the coma grain population may be extremely pristine, unencumbered by a rime and insufficiently irradiated by the Sun to carbonize its surface organics. The comet exhibited a weak 10 μm silicate feature ≃1.18 ± 0.03 above the underlying best-fit 215.32 ± 0.95 K continuum blackbody. Thermal modeling of the observed spectral energy distribution indicates that the coma grains are fractally solid with a porosity factor D = 3 and the peak in the grain size distribution, apeak = 0.6 μm, large. The sub-micron coma grains are dominated by amorphous carbon, with a silicate-to-carbon ratio of 0.80 − 0.20 + 0.25 ? > . The silicate crystalline mass fraction is 0.20 − 0.10 + 0.30 ? > , similar to with other dynamically new comets exhibiting weak 10 μm silicate features. The bolometric dust albedo of the coma dust is 0.14 ± 0.01 at a phase angle of 34. °76, and the average dust production rate, corrected to zero phase, at the epoch of our observations was Afρ ≃ 5340 cm.
Energy decomposition within Einstein-Born-Infeld black holes

We analyze the consequences of the recently found generalization of the Christodoulou-Ruffini black hole mass decomposition for Einstein-Born-Infeld black holes [characterized by the parameters $(Q,M,b)$, where $M = M(M_{irr},Q,b)$, $b$ scale field, $Q$ charge, $M_{irr}$ "irreducible mass", physically meaning the energy of a black hole when its charge is null] and their interactions. We show in this context that their description is largely simplified and can basically be split into two families depending upon the parameter $b|Q|$. If $b|Q|\leq 1/2$, then black holes could have even zero irreducible masses and they always exhibit single, non degenerated, horizons. If $b|Q|>1/2$, then an associated black hole must have a minimum irreducible mass (related to its minimum energy) and has two horizons up to a transitional irreducible mass. For larger irreducible masses, single horizon structures raise again. By assuming that black holes emit thermal uncharged scalar particles, we further show in light of the black hole mass decomposition that one satisfying $b|Q|>1/2$ takes an infinite amount of time to reach the zero temperature, settling down exactly at its minimum energy. Finally, we argue that depending on the fundamental parameter $b$, the radiation (electromagnetic and gravitational) coming from Einstein-Born-Infeld black holes could differ significantly from Einstein-Maxwell ones. Hence, it could be used to assess such a parameter.
The masculine bias in fully gendered languages and ways to avoid it: A study on gender neutral forms in Québec and Swiss French – CORRIGENDUM

The extent to which gender neutral and gendered nouns impact differently upon native French speakers ’ gender representations was examined through a yes-no forced choice task. Swiss (Experiment 1) and Québec (Experiment 2) French-speaking participants were presented with word pairs composed of a gendered first name (e.g., Thomas) and a role (e.g., doctor), and tasked to indicate whether they believed that [first name] could be one of the [role]. Roles varied according to gender stereotypicality (feminine, masculine, non-stereotyped), and were either in a plural masculine (interpretable as generic) or gender neutral (epicenes and group nouns) form. The results indicated that the use of gender neutral forms of roles avoided a strong male bias found for the masculine forms, and that both gender neutral and masculine forms used equal cognitive resources. Further, stereotype effects associated with both gender-neutral and grammatically masculine forms were quite small ( < 1%). These results were highly reliable across both Swiss French and Québec speakers. Our study suggests that gender neutral forms are strong alternatives to the use of the masculine form as default value.
OBSERVATION OF DIFFUSE COSMIC AND ATMOSPHERIC GAMMA RAYS AT BALLOON ALTITUDES WITH AN ELECTRON-TRACKING COMPTON CAMERA

We observed diffuse cosmic and atmospheric gamma rays at balloon altitudes with the Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I (SMILE-I) as the first step toward a future all-sky survey with a high sensitivity. SMILE-I employed an electron-tracking Compton camera comprised of a gaseous electron tracker as a Compton-scattering target and a scintillation camera as an absorber. The balloon carrying the SMILE-I detector was launched from the Sanriku Balloon Center of the Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency on 2006 September 1, and the flight lasted for 6.8 hr, including level flight for 4.1 hr at an altitude of 32–35 km. During the level flight, we successfully detected 420 downward gamma rays between 100 keV and 1 MeV at zenith angles below 60°. To obtain the flux of diffuse cosmic gamma rays, we first simulated their scattering in the atmosphere using Geant4, and for gamma rays detected at an atmospheric depth of 7.0 g cm−2 we found that 50% and 21% of the gamma rays at energies of 150 keV and 1 MeV, respectively, were scattered in the atmosphere prior to reaching the detector. Moreover, by using Geant4 simulations and the QinetiQ atmospheric radiation model, we estimated that the detected events consisted of diffuse cosmic and atmospheric gamma rays (79%), secondary photons produced in the instrument through the interaction between cosmic rays and materials surrounding the detector (19%), and other particles (2%). The obtained growth curve was comparable to Ling's model, and the fluxes of diffuse cosmic and atmospheric gamma rays were consistent with the results of previous experiments. The expected detection sensitivity of a future SMILE experiment measuring gamma rays between 150 keV and 20 MeV was estimated from our SMILE-I results and was found to be 10 times better than that of other experiments at around 1 MeV.
VoxCeleb-PT – a dataset for a speech processing course

This paper introduces VoxCeleb-PT, a small dataset of voices of Portuguese celebrities that can be used as a language-specific extension of the widely used VoxCeleb corpus. Besides introducing the corpus, we also describe three lab assignments where it was used in a one-semester speech processing course: age regression, speaker verification and speech recognition, hoping to highlight the relevance of this dataset as a pedagogical tool. Additionally, this paper confirms the overall limitations of current systems when evaluated in different languages and acoustic conditions: we found an overall degradation of performance on all of the proposed tasks.
Continuous spectra in high-harmonic generation driven by multicycle laser pulses

We present observations of the emission of XUV continua in the 20-37-eV region by high-harmonic generation with 4-7-fs pulses focused onto a Kr gas jet. The underlying mechanism relies on coherent control of the relative delays and phases between individually generated attosecond pulses, achievable by adjusting the chirp of the driving pulses and the interaction geometry. Under adequate negative chirp and phase-matching conditions, the resulting interpulse interference yields a continuum XUV spectrum, which is due to both microscopic and macroscopic (propagation) contributions. This technique opens the route for modifying the phase of individual attosecond pulses and for the coherent synthesis of XUV continua from multicycle driving laser pulses without the need of an isolated attosecond burst. (Less)
Attosecond delays in laser-assisted photodetachment from closed-shell negative ions

We study laser-assisted photodetachment time delays by attosecond pulse trains from the closed-shell negative ions F− and Cl−. We investigate the separability of the delay into two contributions: (i) the Wigner-like delay associated with one-photon ionization by the attosecond pulse train and (ii) the delay associated with the exchange of an additional laser photon in the presence of the potential of the remaining target. Based on the asymptotic form of the wave packet, the latter term is expected to be negligible because the ion is neutralized, leading to a vanishing laser-ion interaction with increasing electron-atom separation. While this asymptotic behavior is verified at high photoelectron energies, we also quantify sharp deviations at low photoelectron energies. Further, these low-energy delays are clearly different for the two studied anions, indicating a breakdown of the universality of laser-ion-induced delays. The fact that the short-range potential can induce a delay of as much as 50 as can have implications for the interpretation of delay measurements also in other systems that lack long-range potential. (Less)