Miracle-dz/UniFAR-FTUs huggingface dataset:
SPIDER VIII - constraints on the stellar initial mass function of early-type galaxies from a variety of spectral features

We perform a spectroscopic study to constrain the stellar initial mass function (IMF) by using a large sample of 24 781 early-type galaxies from the Sloan Digital Sky Survey-based Spheroids Panchromatic Investigation in Different Environmental Regions survey. Clear evidence is found of a trend between IMF and central velocity dispersion (σ0), evolving from a standard Kroupa/Chabrier IMF at σ0 ~ 100 km s-1 towards a more bottom-heavy IMF with increasing σ0, becoming steeper than the Salpeter function at σ0 > 220 km s-1. We analyse a variety of spectral indices, combining gravity-sensitive features, with age- and metallicitysensitive indices, and we also consider the effect of non-solar abundance variations. The indices, corrected to solar scale by means of semi-empirical correlations, are fitted simultaneously with the (nearly solar-scaled) extended MILES (MIUSCAT) stellar population models. Similar conclusions are reached when analysing the spectra with a hybrid approach, combining constraints from direct spectral fitting in the optical with those from IMF-sensitive indices. Our analysis suggests that σ0, rather than [a/Fe], drives the variation of the IMF. Although our analysis cannot discriminate between a single power-law (unimodal) IMF and a low-mass (<0.5Mȯ) tapered (bimodal) IMF, robust constraints can be inferred for the fraction in lowmass stars at birth. This fraction (by mass) is found to increase from ~20 per cent at σ0 ~ 100 km s-1, up to ~80 per cent at σ0 ~ 300 km s-1. However, additional constraints can be provided with stellar mass-to-light (M/L) ratios: unimodal models predict M/L significantly larger than dynamical M/L, across the whole σ0 range, whereas a bimodal IMF is compatible. Our results are robust against individual abundance variations. No significant variation is found in Na and Ca in addition to the expected change from the correlation between [s-1/Fe] and σ0. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
The Herschel/PACS Point Source Catalogue Explanatory Supplement

The Herschel Space Observatory was the fourth cornerstone mission in the European Space Agency (ESA) science programme. It had excellent broad band imaging capabilities in the far-infrared (FIR) and sub-millimetre part of the electromagnetic spectrum. Although the spacecraft finished observing in 2013, it left a large legacy dataset that is far from having been fully explored and still has a great potential for new scientific discoveries. The PACS and SPIRE photometric cameras observed about 8% of the sky in six different wavebands. This document describes the Herschel/PACS Point Source Catalogue (HPPSC), a FIR catalogue based on the broad-band photometric observations of the PACS instrument with filters centred at 70, 100 and 160 microns. We analysed 14842 combined, Level 2.5/Level 3 Herschel/PACS photometric observations. The PACS photometer maps were generated by the JScanam task of the Herschel Interactive Processing Environment (HIPE) v13.0. 0. Sources were identified with the HIPE implementation of SUSSEXtractor, and the flux densities obtained by aperture photometry. We found a total of 108 319 point sources that are considered to be reliable in the 70 micron maps, 131 322 at 100 micron and 251 392 point sources in the 160 micron maps. In addition, our quality control algorithm identified 546 587 candidate sources that were found to be extended and 7 185 160 features which did not pass the signal-to-noise and other criteria to be considered reliable sources. These sources were included in the Extended Source List and Rejected Source List of the HPPSC, respectively. The calculated completeness and photometric accuracy values are based on simulations, where artificial sources were injected into the observational timeline with well controlled flux density values. The actual completeness is a complex function of the source flux, photometric band and the background complexity.
COVID-19: A Retrospective Cohort Study of Nosocomial Transmission in a District General Hospital

Background and objectives Since the outbreak of coronavirus disease 2019 (COVID-19) in the UK, there has been concern that a higher proportion of COVID-19 deaths among inpatients were a result of nosocomial infections. We sought to investigate the proportion of nosocomial COVID-19 infections within our hospital and patient outcomes within this category. Methods This was a retrospective cohort study of 616 patients admitted to the hospital and tested positive for SARS-CoV-2 through a polymerase chain reaction test with particular emphasis on 104 patients who were classed as probable or definite hospital-acquired COVID-19. Demographic and clinical data were extracted from the electronic records of patients, and the outcome of their stay was recorded. Results The median (interquartile range) age of inpatients testing positive for SARS-CoV-2 was 76 (62, 84) years, and the ethnic breakdown of patients was similar to that of the local population. Inpatient mortality was similar to other hospitals in the UK at 41%. Patients with a hospital-acquired infection were older, with a median age of 79 (69, 86) years, more likely to be of White ethnicity, and more likely to die in the hospital. Conclusion Older age was associated with a higher risk of healthcare-associated infection, and as a result, patients were more likely to die.
Spectral decomposition of black-hole perturbations on hyperboloidal slices

In this paper we present a spectral decomposition of solutions to relativistic wave equations described on horizon penetrating hyperboloidal slices within a given Schwarzschild-black-hole background. The wave equa- tion in question is Laplace-transformed which leads to a spatial differential equation with a complex parameter. For initial data which are analytic with respect to a compactified spatial coordinate, this equation is treated with the help of the Mathematica-package in terms of a sophisticated Taylor series analysis. Thereby, all ingredients of the desired spectral decomposition arise explicitly to arbitrarily prescribed accuracy, including quasi normal modes, quasi normal mode amplitudes as well as the jump of the Laplace-transform along the branch cut. Finally, all contributions are put together to obtain via the inverse Laplace transformation the spectral de- composition in question. The paper explains extensively this procedure and includes detailed discussions of relevant aspects, such as the definition of quasi normal modes and the question regarding the contribution of infinity frequencies modes to the early time response of the black hole.
Electroweak vacuum instability and renormalized Higgs field vacuum fluctuations in the inflationary universe

In this work, we investigated the electroweak vacuum instability during or after inflation. In the inflationary Universe, i.e., de Sitter space, the vacuum field fluctuations < δ ϕ 2 > enlarge in proportion to the Hubble scale H2. Therefore, the large inflationary vacuum fluctuations of the Higgs field < δ ϕ 2 > are potentially catastrophic to trigger the vacuum transition to the negative-energy Planck-scale vacuum state and cause an immediate collapse of the Universe. However, the vacuum field fluctuations < δ ϕ 2 >, i.e., the vacuum expectation values have an ultraviolet divergence, and therefore a renormalization is necessary to estimate the physical effects of the vacuum transition. Thus, in this paper, we revisit the electroweak vacuum instability from the perspective of quantum field theory (QFT) in curved space-time, and discuss the dynamical behavior of the homogeneous Higgs field ϕ determined by the effective potential V eff( ϕ ) in curved space-time and the renormalized vacuum fluctuations < δ ϕ 2 >ren via adiabatic regularization and point-splitting regularization. We simply suppose that the Higgs field only couples the gravity via the non-minimal Higgs-gravity coupling ξ(μ). In this scenario, the electroweak vacuum stability is inevitably threatened by the dynamical behavior of the homogeneous Higgs field ϕ, or the formations of AdS domains or bubbles unless the Hubble scale is small enough H< ΛI .
Interacting spins in a cavity: Finite-size effects and symmetry-breaking dynamics

We calculate the ground state and simulate the dynamics of a finite chain of spins with Ising nearest-neighbor interactions and a Dicke collective spin interaction with a single mode cavity field. We recover the signatures of first and second order phase transitions predicted by mean field theory, while for small chains, we find significant and non-trivial finite size effects. Below the first order phase transition, even quite large spin chains of 30-40 spins give rise to a mean photon number and number fluctuations significantly above the mean field vacuum result. Near the second order phase critical point, our calculations reveal photon number fluctuations that grow beyond Poisson statistics with the size of the spin chain. We simulate the stochastic evolution of the system when the cavity output field is subject to homodyne detection. For an initial state close to the first order phase-transition the random character of the measurement process causes a measurement-induced symmetry-breaking in the system. This symmetry-breaking occurs on the time-scale needed for an observer to gather sufficient information to distinguish between the two possible (mean-field) symmetry-broken states.
Mechanically-Exfoliated Stacks of Thin Films of Bi2Te3 Topological Insulators with Enhanced Thermoelectric Performance

The authors report on “graphene-like” mechanical exfoliation of single-crystal Bi2Te3 films and thermoelectric characterization of the stacks of such films. Thermal conductivity of the resulting “pseudosuperlattices” was measured by the “hot disk” and “laser flash” techniques. The room temperature in-plane (cross-plane) thermal conductivity of the stacks decreases by a factor of ∼2.4 (3.5) as compared to bulk. The thermal conductivity reduction with preserved electrical properties leads to strong increase in the thermoelectric figure of merit. It is suggested that the film thinning to few-quintuples and tuning of the Fermi level can help in achieving the topological-insulator surface transport regime with an extraordinary thermoelectric efficiency.
Infall near clusters of galaxies: comparing gas and dark matter velocity profiles

We consider the dynamics in and near galaxy clusters. Gas, dark matter and galaxies are presently falling into the clusters between approximately 1 and 5 virial radii. At very large distances, beyond 10 virial radii, all matter is following the Hubble flow, and inside the virial radius the matter particles have on average zero radial velocity. The cosmological parameters are imprinted on the infall profile of the gas, however, no method exists, which allows a measurement of it. We consider the results of two cosmological simulations (using the numerical codes RAMSES and Gadget) and find that the gas and dark matter radial velocities are very similar. We derive the relevant dynamical equations, in particular the generalized hydrostatic equilibrium equation, including both the expansion of the Universe and the cosmological background. This generalized gas equation is the main new contribution of this paper. We combine these generalized equations with the results of the numerical simulations to estimate the contribution to the measured cluster masses from the radial velocity: inside the virial radius it is negligible, and inside two virial radii the effect is below 40%, in agreement the earlier analyses for DM. We point out how the infall velocity in principle may be observable, by measuring the gas properties to distance of about two virial radii, however, this is practically not possible today.
Orthogonal-state-based and semi-quantum protocols for quantum private comparison in noisy environment

Private comparison is a primitive for many cryptographic tasks, and recently several schemes for the quantum private comparison (QPC) have been proposed, where two users can compare the equality of their secrets with the help of a semi-honest third party (TP) without knowing each other’s secret and without disclosing the same to the TP. In the existing schemes, secrecy is obtained by using conjugate coding, and considering all participants as quantum users who can perform measurement(s) and/or create states in basis other than computational basis. In contrast, here we propose two new protocols for QPC, first of which does not use conjugate coding (uses orthogonal states only) and the second one allows the users other than TP to be classical whose activities are restricted to either reflecting a quantum state or measuring it in computational basis. Further, the performance of the protocols is evaluated under various noise models.
Pressure in Lemaître–Tolman–Bondi solutions and cosmologies

Lemaître–Tolman–Bondi solutions have traditionally been confined to systems with no pressure in which the gravity is due to massive dust, but the solutions are little changed in form if, as in cosmology, the pressure is uniform in space at each comoving time. This allows the equations of cosmology to be deduced in a manner that more closely resembles classical mechanics. It also gives some inhomogeneous solutions with growing condensations and black holes. We give criteria by which the sizes of different closed models of the Universe can be compared and discuss conditions for self-closure of inhomogeneous cosmologies with a Λ ? > -term.
Using Formic Acid to Promote Bacterial Cellulose Production and Analysis of Its Material Properties for Food Packaging Applications

Bacterial cellulose (BC) is a microbial cellulose that presents various characteristics such as high mechanical strength, high water content, and great biocompatibility and biodegradability. Therefore, it provides great potential to be applied in functional packaging applications. In this study, formic acid (80 µg/mL) was found to promote BC production (a 23% increase in yield from 5.18 to 6.38 g/L) utilizing quorum sensing-related gene (ginI) induction within 5 days of cultivation. The enhancement in BC relied on the addition of FA in static culture, and there was no need to shift to another production system, thus providing an economical approach for industrial production. The characteristic analysis showed that the induced BC still retained its high water-holding capacity (98.4%) with no other structure, morphology, or property changes including chemical groups, crystallinity (80.4%), and thermostability (with Tmax at 360 °C). Analysis of the produced BC showed that it is a suitable, ecofriendly biomaterial for food packaging, and its further evaluation will be accomplished in future studies.
MODELING THE RED SEQUENCE: HIERARCHICAL GROWTH YET SLOW LUMINOSITY EVOLUTION

We explore the effects of mergers on the evolution of massive early-type galaxies by modeling the evolution of their stellar populations in a hierarchical context. We investigate how a realistic red sequence population set up by z ∼ 1 evolves under different assumptions for the merger and star formation histories, comparing changes in color, luminosity, and mass. The purely passive fading of existing red sequence galaxies, with no further mergers or star formation, results in dramatic changes at the bright end of the luminosity function and color–magnitude relation. Without mergers there is too much evolution in luminosity at a fixed space density compared to observations. The change in color and magnitude at a fixed mass resembles that of a passively evolving population that formed relatively recently, at z ∼ 2. Mergers among the red sequence population (“dry mergers”) occurring after z = 1 build up mass, counteracting the fading of the existing stellar populations to give smaller changes in both color and luminosity for massive galaxies. By allowing some galaxies to migrate from the blue cloud onto the red sequence after z = 1 through gas-rich mergers, younger stellar populations are added to the red sequence. This manifestation of the progenitor bias increases the scatter in age and results in even smaller changes in color and luminosity between z = 1 and z = 0 at a fixed mass. The resultant evolution appears much slower, resembling the passive evolution of a population that formed at high redshift (z ∼ 3–5), and is in closer agreement with observations. We conclude that measurements of the luminosity and color evolution alone are not sufficient to distinguish between the purely passive evolution of an old population and cosmologically motivated hierarchical growth, although these scenarios have very different implications for the mass growth of early-type galaxies over the last half of cosmic history.
A two-point correlation function for Galactic halo stars

We describe a correlation function statistic that quantifies the amount of spatial and kinematic substructure in the stellar halo. We test this statistic using model stellar halo realizations constructed from the Aquarius suite of six high-resolution cosmological N-body simulations, in combination with the GALFORM semi-analytic galaxy formation model. The stellar haloes in the these simulations, which form from disrupted satellites accreted between redshifts 1 and 7, show considerable scatter in the nature of their substructure. We find that our statistic can distinguish between these different realizations of plausible models for the global structure of the Milky Way stellar halo. We apply our statistic to a catalogue of blue horizontal branch stars identified in the Sloan Digital Sky Survey. In our Λ cold dark matter simulations, we find examples of haloes with spatial and kinematic substructure consistent with the available Milky Way data in the outer halo. For the inner halo, the models predict stronger clustering than observed, suggesting the existence of a smooth component, not currently included in our simulations.
Factors Associated with Anxiety, Depression, and Stress in Peruvian University Students during the COVID-19 Pandemic

During the COVID-19 pandemic, university students have adopted measures that completely transformed their educational environment, and this has generated an increase in psychological stress. The present study aimed to identify the factors associated with anxiety, depression, and stress in students at a university in Peru during the COVID-19 pandemic in 2020. We conducted a cross-sectional analytical study in students in Lima, Peru. The DASS-21 scale was used to measure levels of depression, anxiety, and stress and associate it with socio-educational and COVID-19-related variables using generalized linear models with Poisson distribution, log link, and robust variance. Of 400 students surveyed, 19.2%, 23.2% and 17.2% of students presented depression, anxiety, and stress, respectively. The frequency of depression (PR = 0.91, 95%CI: 0.84–0.99), anxiety (PR = 0.90, 95%CI: 0.83–0.99) and stress (PR = 0.92, 95%CI: 0.86–0.99) was lower in women. The students of the engineering and business faculty presented a higher frequency of anxiety (PR = 1.11, 95%CI: 1.00–1.22). There was a greater frequency of presenting anxiety, depression and stress in students who worked in a different area of health or did not work. Our results suggest the importance of promoting mental health awareness campaigns in university students due to the constant academic load they have.
The «materialization» of forces: Why confounding mathematical concept and physical entity makes the design of metamaterials arduous

In this paper we show why the postulation scheme based on forces and couples is detrimental when designing novel metamaterials. Instead, the most effective postulation scheme for mechanics is that based on the Principle of Virtual Work formulated by, for example, d'Alembert, Lagrange, Piola, and Paul Germain. In fact, generalized continuum mechanics can be formulated in a coherent way only by basing its foundations on the Principle of Virtual Work while the problem of synthesis of novel metamaterials can be efficiently confronted only when introducing generalized continua as their model at macroscopic level. Once work functionals are postulated, the set of involved generalized forces are identified using the representation theorem for distributions by Laurent Schwartz, forces in particular being zeroth order distributions. Actually, only when limiting the class of considered internal work functionals to first order distributions is the Principle of Virtual Work equivalent to the balances of forces and couples. The predominant Role of the Principle of Virtual Work has been denied by those inductivist scholars who claim that balance laws can be induced by experimentation. The Principle of Virtual Work postulation more truly fits in a falsificationist approach to epistemology.
The chemical composition of red giants in 47 Tucanae. II. Magnesium isotopes and pollution scenarios

The phenomenon of multiple populations in globular clusters is still far from understood, with several proposed mechanisms to explain the observed behaviour. The study of elemental and isotopic abundance patterns are crucial for investigating the differences among candidate pollution mechanisms. We derive magnesium isotopic ratios for 13 stars in the globular cluster 47 Tucanae (NGC 104) to provide new, detailed information about the nucleosynthesis that has occurred within the cluster. For the first time, the impact of 3D model stellar atmospheres on the derived Mg isotopic ratios is investigated. Using both tailored 1D atmospheric models and 3D hydrodynamical models, we derive magnesium isotopic ratios from four features of MgH near 5135{\AA} in 13 giants near the tip of the RGB, using high signal-to-noise, high-resolution spectra. We derive the magnesium isotopic ratios for all stars and find no significant offset of the isotopic distribution between the pristine and the polluted populations. Furthermore, we do not detect any statistically significant differences in the spread in the Mg isotopes in either population. No trends were found between the Mg isotopes and [Al/Fe]. The inclusion of 3D atmospheres has a significant impact on the derived 25Mg/24Mg ratio, increasing it by a factor of up to 2.5, compared to 1D. The 26Mg/24Mg ratio, on the other hand, essentially remains unchanged. We confirm the results seen from other globular clusters, where no strong variation in the isotopic ratios is observed between stellar populations, for observed ranges in [Al/Fe]. We see no evidence for any significant activation of the Mg-Al burning chain. The use of 3D atmospheres causes an increase of a factor of up to 2.5 in the fraction of 25Mg, resolving part of the discrepancy between the observed isotopic fraction and the predictions from pollution models.
Zodiacal Exoplanets in Time (ZEIT). VI. A Three-planet System in the Hyades Cluster Including an Earth-sized Planet

Planets in young clusters are powerful probes of the evolution of planetary systems. Here we report the discovery of three planets transiting EPIC 247589423, a late-K dwarf in the Hyades (≃800 Myr) cluster, and robust detection limits for additional planets in the system. The planets were identified from their K2 light curves as part of our survey of young clusters and star-forming regions. The smallest planet has a radius comparable to Earth ( ), making it one of the few Earth-sized planets with a known, young age. The two larger planets are likely a mini-Neptune and a super-Earth, with radii of and , respectively. The predicted radial velocity signals from these planets are between 0.4 and 2 m s−1, achievable with modern precision RV spectrographs. Because the target star is bright (V = 11.2) and has relatively low-amplitude stellar variability for a young star (2–6 mmag), EPIC 247589423 hosts the best known planets in a young open cluster for precise radial velocity follow-up, enabling a robust test of earlier claims that young planets are less dense than their older counterparts.