Miracle-dz/UniFAR-FTUs huggingface dataset:
Statistical Properties Of Superflares On Solar-Type Stars With Kepler Data

Superflares are flares that release total energy 10$\sim$10$^{4}$ times greater than that of the biggest solar flares with energy of $\sim$10$^{32}$ erg. We searched superflares on solar-type stars (G-type main sequence stars) using the Kepler 30-min (long) and 1-min (short) cadence data. We found more than 1500 superflares on 279 stars from 30-min cadence data (Q0-6) and 187 superflares on 23 stars from 1-min cadence data (Q0-17). The bolometric energy of detected superflares ranges from the order of 10$^{32}$ erg to 10$^{36}$ erg. Using these data, we found that the occurrence frequency ($dN/dE$) of superflares is expressed as a power-law function of flare energy ($E$) with the index of -1.5 for $10^{33}<E<10^{36}$erg. Most of the superflare stars show quasi-periodic light variations with the amplitude of a few percent, which can be explained by the rotation of the star with large starspots. The bolometric energy released by flares is consistent with the magnetic energy stored around such large starspots. Furthermore, our analyses indicate that the occurrence frequency of superflares depends on the rotation period, and that the flare frequency increases as the rotation period decreases. However, the energy of the largest flares observed in a given period bin does not show any clear correlation with the rotation period. We also found that the duration of superflares increases with the flare energy as $E^{0.39+/-0.03}$. This can be explained if we assume the time-scale of flares is determined by the Alfv$\acute{\rm{e}}$n time.
The Role of Phosphate Fertilization on Physiological Responses of the Young Bertholletia excelsa Plants Grown in a P-Deficient Amazon Ferralsol

Phosphorus (P) reacts with soil minerals, which makes it less available to plants. Considering that Amazonian soils have a low pH and nutrient availability, both of these properties contribute to an increase in P limitation. Here, we investigate how the addition of P to the substrate affects morpho-physiological traits of Brazil nut trees (Bertholletia excelsa Bonpl.). The experiment was carried out in a greenhouse with 24-month-old saplings, and the P treatments consisted of a control (Ferrasol without P addition) and 100, 200, 400, and 500 mg P kg−1 of added to the soil. When B. excelsa saplings were fertilized with phosphate, the N:P leaf ratio reduced from 50 to 26. Addition of P favored the photochemical efficiency of PSII (FV/FM), and the application of 200 mg kg−1 increased photosynthesis (PN) by 50%. Furthermore, phosphorus enhanced light and nutrient use efficiency. An increase in B. excelsa dry biomass was observed when 200 mg P kg−1 was added, with maximum yield occurring at 306.2 mg P kg−1. Physiological parameters suggest robust responses by B. excelsa to P fertilization. In addition, our findings reveal the critical role of P on B. excelsa growth in Ferralsol, as well as the potential of P fertilization to improve functional traits of this important Amazonian tree.
THE BULK LORENTZ FACTOR OF OUTFLOW POWERING X-RAY FLARE IN GAMMA-RAY BURST AFTERGLOW

We develop two methods to estimate the bulk Lorentz factor of X-ray flare outflow. In the first method, the outflow is assumed to be baryonic and is accelerated by the thermal pressure, for which the final bulk Lorentz factor is limited by the outflow luminosity as well as the initial radius of the outflow getting accelerated. Such a method may be applied to a considerable fraction of flares. The second method, based on the curvature effect interpretation of the quick decline of the flare, can give a tightly constrained estimate of the bulk Lorentz factor but can only be applied to a few giant flares. The results obtained in these two different ways are consistent with each other. The obtained bulk Lorentz factor (or just upper limit) of the X-ray flare outflows, ranging from ten to a few hundreds, is generally smaller than that of the gamma-ray burst outflows.
Density anomalies and high-order jamming crossovers

Jamming crossovers occur at zero temperature in assemblies of particles interacting via finite range repulsive potentials, when on increasing the density particles make contacts with those of subsequent coordination shells. Density anomalies, including an increased diffusivity upon isothermal compression and a negative thermal expansion coefficient, are the finite temperature signatures of the jamming crossovers. In this manuscript we show that the jamming crossovers are correlated to an increase of the non affine response of the system to density changes, and clarify that jammed systems evolve upon compression through subsequent Eshlby-like plastic instabilities.
The GAPS programme with HARPS-N at TNG - IX. The multi-planet system KELT-6: Detection of the planet KELT-6 c and measurement of the Rossiter-McLaughlin effect for KELT-6 b

Aims. For more than 1.5 years we spectroscopically monitored the star KELT-6 (BD+31 2447), which is known to host the transiting hot-Saturn KELT-6 b, because a previously observed long-term trend in radial velocity time series suggested that there is an outer companion. Methods. We collected a total of 93 new spectra with the HARPS-N and TRES spectrographs. A spectroscopic transit of KELT-6 b was observed with HARPS-N, and simultaneous photometry was obtained with the IAC-80 telescope. Results. We proved the existence of an outer planet with a mininum mass M p sin i = 3.71 ± 0.21 M Jup and a moderately eccentric orbit ( e = 0.21 -0.036 +0.039 ) of period P ~ 3.5 years. We improved the orbital solution of KELT-6 b and obtained the first measurement of the Rossiter-McLaughlin effect, showing that the planet has a likely circular, prograde, and slightly misaligned orbit with a projected spin-orbit angle of λ = −36 ± 11 degrees. We improved the KELT-6 b transit ephemeris from photometry and provide new measurements of the stellar parameters. KELT-6 appears as an interesting case for studying the formation and evolution of multi-planet systems.
Learning successful implementation of Chatbots in businesses from B2B customer experience perspective

Artificial intelligence empowered Chatbots are altering the nature of service interfaces which has further resulted in raised expectations from Chatbots to understand customer's social interactions and respond them within the turnaround time. To close this research gap, we conduct an exploratory study in two phases‐industry's perspective and B2B customer's perspective and analyze results with the help of NVIVO 12 plus and Leximancer. The findings reveal perceived risk with respect to Chatbots is high, complex pricing structure along with nonavailability of testing options makes the pre purchase more complex. Moreover, interactive speed, customization especially with respect to language issues, integration with other platforms is some of the major themes which influence customer experience. Advancements in AI, natural language processing and more testing at all phases will bring efficiency, automation first strategies. Further, our findings suggest Chatbots must provide more personalization, scalability and omni channel engagement and focus on delivering more enhanced customer experience. Chatbots must offer a grievance management dashboard where the customer can see live queries, resolved queries, present queries status and so on to get transparency. Chatbots streamline the lead qualification process, greatly improve, and speed up the data collection therefore, enhancing customer experience.
Quantum phase transitions of the spin-boson model within multi-coherent-states

A variational approach based on the multi-coherent-state ansatz with asymmetric parameters is employed to study the ground state of the spin-boson model. Without any artificial approximations except for the finite number of the coherent states, we find the robust Gaussian critical behavior in the whole sub-Ohmic bath regime. The converged critical coupling strength can be estimated with the $1/N$ scaling, where $N $ is the number of the coherent states. It is strongly demonstrated the breakdown of the well-known quantum-to-classical mapping for $1/2<s<1$. In addition, the entanglement entropy displays more steep jump around the critical points for the Ohmic bath than the sub-Ohmic bath.
RawNet: Advanced end-to-end deep neural network using raw waveforms for text-independent speaker verification

Recently, direct modeling of raw waveforms using deep neural networks has been widely studied for a number of tasks in audio domains. In speaker verification, however, utilization of raw waveforms is in its preliminary phase, requiring further investigation. In this study, we explore end-to-end deep neural networks that input raw waveforms to improve various aspects: front-end speaker embedding extraction including model architecture, pre-training scheme, additional objective functions, and back-end classification. Adjustment of model architecture using a pre-training scheme can extract speaker embeddings, giving a significant improvement in performance. Additional objective functions simplify the process of extracting speaker embeddings by merging conventional two-phase processes: extracting utterance-level features such as i-vectors or x-vectors and the feature enhancement phase, e.g., linear discriminant analysis. Effective back-end classification models that suit the proposed speaker embedding are also explored. We propose an end-to-end system that comprises two deep neural networks, one front-end for utterance-level speaker embedding extraction and the other for back-end classification. Experiments conducted on the VoxCeleb1 dataset demonstrate that the proposed model achieves state-of-the-art performance among systems without data augmentation. The proposed system is also comparable to the state-of-the-art x-vector system that adopts data augmentation.
EXTENDED Lyα EMISSION FROM INTERACTING GALAXIES AT HIGH REDSHIFTS

Recent observations have discovered a population of extended Lyα sources, dubbed Lyα blobs (LABs), at high redshift z ∼ 2–6.6. These LABs typically have a luminosity of L ∼ 1042–1044 erg s−1, and a size of tens of kiloparsecs, with some giant ones reaching up to D ∼ 100 kpc. However, the origin of these LABs is not well understood. In this paper, we investigate a merger model for the formation of LABs by studying Lyα emission from interacting galaxies at high redshifts by means of a combination of hydrodynamics simulations with three-dimensional radiative transfer calculations. Our galaxy simulations focus on a set of binary major mergers of galaxies with a mass range of 3–7 × 1012 M☉ in the redshift range z ∼ 3–7, and we use the newly improved ART2 code to perform the radiative transfer calculations, which couple multi-wavelength continuum, ionization of hydrogen, and Lyα line emission. We find that intense star formation and enhanced cooling induced by gravitational interaction produce strong Lyα emission from these merging galaxies. The Lyα emission appears to be extended due to the extended distribution of sources and gas. During the close encounter of galaxy progenitors when the star formation rate peaks at ∼103 M☉ yr−1, our model produces LABs with luminosity of L ∼ 1042–1044 erg s−1, and size of D ∼ 10–20 kpc at z > 6 and D ∼ 20–50 kpc at z ∼ 3, in broad agreement with observations in the same redshift range. Our results suggest that merging galaxies may produce some typical LABs as observed, but the giant ones may be produced by mergers more massive than those in our model, or a combination of mergers and cold accretion from filaments on a large scale.
Layered quantum Hall insulators with ultracold atoms

We consider a generalization of the two-dimensional (2D) quantum Hall insulator to a noncompact, non-Abelian gauge group, the Heisenberg-Weyl group. We show that this kind of insulator is actually a layered three-dimensional (3D) insulator with nontrivial topology. We further show that nontrivial combinations of quantized transverse conductivities can be engineered with the help of a staggered potential. We investigate the robustness and topological nature of this conductivity and connect it to the surface modes of the system. We also propose a simple experimental realization with ultracold atoms in 3D confined to a 2D square lattice with the third dimension being mapped to a gauge coordinate.
A disk-corona model for the low/hard state of black hole X-ray binaries

A disk-corona model for fitting the low/hard (LH) state of the associated steady jet in black hole X-ray binaries (BHXBs) is proposed based on the large-scale magnetic field configuration that arises from the coexistence of the Blandford-Znajek (BZ) and Blandford-Payne (BP) processes, where the magnetic field configuration for the BP process is determined by the requirement of energy conversion from Poynting energy flux into kinetic energy flux in the jet. It is found that corona current is crucial to guarantee the consistency of the jet launching from the accretion disk. The relative importance of the BZ and BP processes in powering jets from black hole accretion disks is discussed, and the LH state of several BHXBs is fitted based on our model. In addition, we suggest that magnetic field configuration can be regarded as the second parameter for governing the state transition of BHXBs.
Higgs boson production via gluon fusion: Soft-gluon resummation including mass effects

We analyze soft and collinear gluon resummation effects at the N$^3$LL level for Standard Model Higgs boson production via gluon fusion $gg\to H$ and the neutral scalar and pseudoscalar Higgs bosons of the minimal supersymmetric extension at the N$^3$LL and NNLL level, respectively. We introduce refinements in the treatment of quark mass effects and subleading collinear gluon effects within the resummation. Soft and collinear gluon resummation effects amount to up to about 5% beyond the fixed-order results for scalar and pseudoscalar Higgs boson production.
Constraints on mass loss and self-enrichment scenarios for the globular clusters of the Fornax dSph

Recently, high-dispersion spectroscopy has demonstrated conclusively that four of the five globular clusters (GCs) in the Fornax dwarf spheroidal galaxy are very metal-poor with [Fe/H]<−2. The remaining cluster, Fornax 4, has [Fe/H] =−1.4. This is in stark contrast to the field star metallicity distribution which sh ows a broad peak around [Fe/H]≈ −1 with only a few percent of the stars having [Fe/H]<−2. If we only consider stars and clusters with [Fe/H]<−2 we thus find an extremely high GC specific frequency, SN ≈ 400, implying by far the highest ratio of GCs to field stars kno wn anywhere. We estimate that about 1/5‐1/4 of all stars in the Fornax dSph with [Fe/H]<−2 belong to the four most metal-poor GCs. These GCs could, therefore, at most have been a factor of 4‐5 more massive initially. Yet, the Fornax GCs appear to share the same anomalous chemical abundance patterns known from Milky Way GCs, commonly attributed to the presence of multiple stellar generations within the clusters. The extreme ratio of metal-poor GC- versus field stars in the Fornax dSph is di ffi cult to reconcile with scenarios for self-enrichment and ea rly evolution of GCs in which a large fraction (90%‐95%) of the first-generation sta rs have been lost. It also suggests that the GCs may not have formed as part of a larger population of now disrupted clusters with an initial power-law mass distribution. The Fornax dSph may be a rosetta stone for constraining theories of the formation, self-enr ichment and early dynamical evolution of star clusters.
Generating shortcuts to adiabaticity in quantum and classical dynamics

Transitionless quantum driving achieves adiabatic evolution in a hurry, using a counterdiabatic Hamiltonian to stifle nonadiabatic transitions. Here this shortcut to adiabaticity is cast in terms of a generator of adiabatic transport. This yields a classical analog of transitionless driving, and provides a strategy for constructing quantal counterdiabatic Hamiltonians. As an application of this framework, exact classical and quantal counterdiabatic terms are obtained for a particle in a box and for even-power-law potentials in one degree of freedom.
A GENERALIZED POWER-LAW DIAGNOSTIC FOR INFRARED GALAXIES AT z > 1: ACTIVE GALACTIC NUCLEI AND HOT INTERSTELLAR DUST

I present a generalized power-law (PL) diagnostic which allows one to identify the presence of active galactic nuclei (AGNs) in infrared (IR) galaxies at z > 1, down to flux densities at which the extragalactic IR background is mostly resolved. I derive this diagnostic from the analysis of 174 galaxies with Sν(24 μm)>80 μJy and spectroscopic redshifts zspec > 1 in the Chandra Deep Field South, for which I study the rest-frame UV/optical/near-IR spectral energy distributions (SEDs), after subtracting a hot-dust, PL component with three possible spectral indices α = 1.3, 2.0, and 3.0. I obtain that 35% of these 24 μm sources are power-law composite galaxies (PLCGs), which I define as those galaxies for which the SED fitting with stellar templates, without any previous PL subtraction, can be rejected with >2σ confidence. Subtracting the PL component from the PLCG SEDs produces stellar mass correction factors <1.5 in >80% of cases. The PLCG incidence is especially high (47%) at 1.0 < z < 1.5. To unveil which PLCGs host AGNs, I conduct a combined analysis of 4 Ms X-ray data, galaxy morphologies, and a graybody modeling of the hot dust. I find that (1) 77% of all the X-ray AGNs in my 24 μm sample at 1.0 < z < 1.5 are recognized by the PLCG criterion; (2) PLCGs with α = 1.3 or 2.0 have regular morphologies and Tdust ≳ 1000 K, indicating nuclear activity. Instead, PLCGs with α = 3.0 are characterized by disturbed galaxy dynamics, and a hot interstellar medium can explain their dust temperatures Tdust ∼ 700–800 K. Overall, my results indicate that the fraction of AGNs among 24 μm sources is between ∼30% and 52% at 1.0 < z < 1.5.
Modeling the physical properties in the ISM of the low-metallicity galaxy NGC4214

We present a model for the interstellar medium of NGC4214 with the objective to probe the physical conditions in the two main star-forming regions and their connection with the star formation activity of the galaxy. We used the spectral synthesis code Cloudy to model an HII region and the associated photodissociation region (PDR) to reproduce the emission of mid- and far-infrared fine-structure cooling lines from the Spitzer and Herschel space telescopes for these two regions. Input parameters of the model, such as elemental abundances and star formation history, are guided by earlier studies of the galaxy, and we investigated the effect of the mode in which star formation takes place (bursty or continuous) on the line emission. Furthermore, we tested the effect of adding pressure support with magnetic fields and turbulence on the line predictions. We find that this model can satisfactorily predict (within a factor of ~2) all observed lines that originate from the ionized medium ([SIV] 10.5um, [NeIII] 15.6um, [SIII] 18.7um, [SIII] 33.5um, and [OIII] 88um), with the exception of [NeII] 12.8um and [NII] 122um, which may arise from a lower ionization medium. In the PDR, the [OI] 63um, [OI] 145um, and [CII] 157um lines are matched within a factor of ~5 and work better when weak pressure support is added to the thermal pressure or when the PDR clouds are placed farther away from the HII regions and have covering factors lower than unity. Our models of the HII region agree with different evolutionary stages found in previous studies, with a more evolved, diffuse central region, and a younger, more compact southern region. However, the local PDR conditions are averaged out on the 175 pc scales that we probe and do not reflect differences observed in the star formation properties of the two regions.
A holographic model for large N thermal QCD

We summarize the dual gravity description for a thermal gauge theory, reviewing the key features of our holographic model of large N QCD (Mia et al 2010 Nucl. Phys. B 839 187, Mia et al 2010 Phys. Rev. D 82 026004) and elaborating on some new results. The theory has matter in the fundamental representation and the gauge coupling runs logarithmically with energy scale at low energies. At the highest energies, the theory becomes approximately scale invariant, much like what we would expect for large N QCD although not with asymptotic freedom. In this limit, the theory has a gravity dual captured by an almost classical supergravity description with a controlled quantum behavior, such that by renormalizing the supergravity action, we can compute the stress tensor of the dual gauge theory. From the stress tensor, we obtain the shear viscosity and the entropy of the medium at a temperature T, and the violation of the bound for the viscosity to the entropy ratio is then investigated. By considering dynamics of open strings in curved spacetime described by the supergravity limit, we compute the drag and diffusion coefficients for a heavy parton traversing the thermal medium. It is shown that both coefficients have a logarithmic dependence on momentum, consistent with pQCD expectations. Finally, we study the confinement/deconfinement mechanism for quarks by analyzing open strings in the presence of the flavor seven branes. We find linear confinement of quarks at low temperatures, while at high temperatures the quarkonium states melt, a behavior consistent with the existence of a deconfined phase.
THE INTERACTION OF THE FERMI BUBBLES WITH THE MILKY WAY’S HOT GAS HALO

The Fermi bubbles are two lobes filled with non-thermal particles that emit gamma rays, extend vertically from the Galactic center, and formed from either nuclear star formation or accretion activity on Sgr A*. Simulations predict a range of shock strengths as the bubbles expand into the surrounding hot gas halo ( K), but with significant uncertainties in the energetics, age, and thermal gas structure. The bubbles should contain thermal gas with temperatures between 106 and 108 K, with potential X-ray signatures. In this work, we constrain the bubbles’ thermal gas structure by modeling O vii and O viii emission line strengths from archival XMM-Newton and Suzaku data. Our emission model includes a hot thermal volume-filled bubble component cospatial with the gamma-ray region, and a shell of compressed material. We find that a bubble/shell model with cm−3 and with log(T) ≈ 6.60–6.70 is consistent with the observed line intensities. In the framework of a continuous Galactic outflow, we infer a bubble expansion rate, age, and energy injection rate of km s−1, Myr, and erg s−1. These estimates are consistent with the bubbles forming from a Sgr A* accretion event rather than from nuclear star formation.
Detailed AGB evolutionary models and near infrared colours of intermediate-age stellar populations: Tests on star clusters

We investigate the influence of asymptotic giant branch (AGB) stars on integrated colours of star clusters of ages between ∼100 Myr and a few gigayears, and composition typical for the Magellanic Clouds. We use state-of-the-art stellar evolution models that cover the full thermal pulse phase, and take the influence of dusty envelopes on the emerging spectra into account. We present an alternative approach to the usual isochrone method, and compute integrated fluxes and colours using a Monte Carlo technique that enables us to take into account statistical fluctuations due to the typical small number of cluster stars. We demonstrate how the statistical variations in the number of AGB stars and the temperature and luminosity variations during thermal pulses fundamentally limit the accuracy of the comparison (and calibration, for population synthesis models that require a calibration of the AGB contribution to the total luminosity) with star cluster integrated photometries. When compared to observed integrated colours of individual and stacked clusters in the Magellanic Clouds, our predictions match most of the observations well, when statistical fluctuations are taken into account, although there are discrepancies in narrow age ranges with some (but not all) sets of observations.