Miracle-dz/UniFAR-FTUs huggingface dataset:
Deep learning and density-functional theory

We show that deep neural networks can be integrated into, or fully replace, the Kohn-Sham density functional theory (DFT) scheme for multielectron systems in simple harmonic oscillator and random external potentials with no feature engineering. We first show that self-consistent charge densities calculated with different exchange-correlation functionals can be used as input to an extensive deep neural network to make predictions for correlation, exchange, external, kinetic, and total energies simultaneously. Additionally, we show that one can make all of the same predictions with the external potential rather than the self-consistent charge density, which allows one to circumvent the Kohn-Sham DFT scheme altogether. We then show that a self-consistent charge density found from a nonlocal exchange-correlation functional can be used to make energy predictions for a semilocal exchange-correlation functional. Lastly, we use a deep convolutional inverse graphics network to predict the charge density given an external potential for different exchange-correlation functionals and assess the viability of the predicted charge densities. This work shows that extensive deep neural networks are generalizable and transferable given the variability of the potentials (maximum total energy range $\ensuremath{\approx}100$ Ha) because they require no feature engineering and because they can scale to an arbitrary system size with an $O(N)$ computational cost.
Exotic solutions in General Relativity: Traversable wormholes and 'warp drive' spacetimes

The General Theory of Relativity has been an extremely successful theory, with a well established experimental footing, at least for weak gravitational fields. Its predictions range from the existence of black holes, gravitational radiation to the cosmological models, predicting a primordial beginning, namely the big-bang. All these solutions have been obtained by first considering a plausible distribution of matter, and through the Einstein field equation, the spacetime metric of the geometry is determined. However, one may solve the Einstein field equation in the reverse direction, namely, one first considers an interesting and exotic spacetime metric, then finds the matter source responsible for the respective geometry. In this manner, it was found that some of these solutions possess a peculiar property, namely 'exotic matter,' involving a stress-energy tensor that violates the null energy condition. These geometries also allow closed timelike curves, with the respective causality violations. These solutions are primarily useful as 'gedanken-experiments' and as a theoretician's probe of the foundations of general relativity, and include traversable wormholes and superluminal 'warp drive' spacetimes. Thus, one may be tempted to denote these geometries as 'exotic' solutions of the Einstein field equation, as they violate the energy conditions and generate closed timelike curves. In this article, in addition to extensively exploring interesting features, in particular, the physical properties and characteristics of these 'exotic spacetimes,' we also analyze other non-trivial general relativistic geometries which generate closed timelike curves.
Fungal bioconversion of brewery by-products

Waste management of brewery by-products is economically and environmentally problematic. In the frame of bio-recycling, this study aims to investigate the bioconversion of brewery by-products by filamentous fungi. Pleurotus ostreatus and Lentinula edodes were grown on different substrates based on brewer’s spent grains (fresh and dry). Afterwards, fatty acids and sterols were determined. Following the selection of the suitable substrate composition for fungal growth, results showed that fatty acids composition of fungal biomasses varied significantly as a function of substrate and fungal strain. Interestingly, fungal fat might be used for human nutrition due to low SFA/UFA ratios (~0.2–0.4) within the same range of vegetal oils. Sterols profile of fungi biomass revealed the predominance of ergosterol. Also, it was found that the fungi growing on by-products slightly reduced the cholesterol contents. As such, this approach focusing on the bioconversion of by-products using fungi can provide biomasses with a fat composition suitable for feed and human consumption.
Late-time spectral line formation in Type IIb supernovae, with application to SN 1993J, SN 2008ax, and SN 2011dh

We investigate line formation processes in Type IIb supernovae (SNe) from 100 to 500 days post-explosion using spectral synthesis calculations. The modeling identifies the nuclear burning layers and physical mechanisms that produce the major emission lines, and the diagnostic potential of these. We compare the model calculations with data on the three best observed Type IIb SNe to-date - SN 1993J, SN 2008ax, and SN 2011dh. Oxygen nucleosynthesis depends sensitively on the main-sequence mass of the star and modeling of the [O I] 6300, 6364 lines constrains the progenitors of these three SNe to the M_ZAMS=12-16 M_sun range (ejected oxygen masses 0.3-0.9 M_sun), with SN 2011dh towards the lower end and SN 1993J towards the upper end of the range. The high ejecta masses from M_ZAMS >= 17 M_sun progenitors give rise to brighter nebular phase emission lines than observed. Nucleosynthesis analysis thus supports a scenario of low/moderate mass progenitors for Type IIb SNe, and by implication an origin in binary systems. We demonstrate how oxygen and magnesium recombination lines may be combined to diagnose the magnesium mass in the SN ejecta. For SN 2011dh, a magnesium mass of of 0.02-0.14 M_sun is derived, which gives a Mg/O production ratio consistent with the solar value. Nitrogen left in the He envelope from CNO-burning gives strong [N II] 6548, 6583 emission lines that dominate over H-alpha emission in our models. The hydrogen envelopes of Type IIb SNe are too small and dilute to produce any noticeable H-alpha emission or absorption after ~150 days, and nebular phase emission seen around 6550 A is in many cases likely caused by [N II] 6548, 6583. Finally, the influence of radiative transport on the emergent line profiles is investigated. (abridged)
Constraints on supermassive black hole spins from observations of active galaxy jets

We discuss the origin of the low-energy cutoff, or LEC, seen in the radio spectra of many extragalactic jets and relate this to the spin of the supermassive black holes that presumably power them. Pion decay via proton-proton collisions is a possible mechanism to supply a secondary positron population with a low energy limit. We expect that pion production would occur in advection dominated accretion flows or ADAFs. In radiatively inefficient ADAFs the heat energy of the accreting gas is unable to radiate in less than the accretion time and the particle temperature could be high enough so that thermal protons can yield such pion production. Strong starbursts are another option for the injection of a truncated particle population into the jet. The role of both mechanisms is discussed with respect to the black hole spin estimate. The energy demanded to produce the pion decay process involves a minimum threshold for kinetic energy of the interacting protons. Therefore the mean proton speed in the flow can determine whether a LEC is generated. In ADAFs the random velocity of the protons can exceed the minimum speed limit of pion production around the jet launching region in the innermost part of the flow. Finally we summarize the additional work needed to put the model assumptions on a more rigorous basis.
An X-ray view of 82 LINERs with Chandra and XMM-Newton data

We present the results of a homogeneous X-ray analysis for 82 nearby low-ionisation, narrow emission-line regions (LINERs) selected from the catalogue of Carrillo et al. (1999, Rev. Mex. Astron. Astrofis., 35, 187). All sources have available Chandra (68 sources) and/or XMM-Newton (55 sources) observations. This is the largest sample of LINERs with X-ray spectral data (60 out of the 82 objects), and it significantly improves our previous analysis based on Chandra data for 51 LINERs (Gonzalez-Martin et al. 2006b, A&A, 460, 45). It both increases the sample size and adds XMM-Newton data . New models permit the inclusion of double absorbers in the spectral fits. Nuclear X-ray morphology is inferred from the compactness of detected nuclear sources in the hard band (4.5–8.0 keV). Sixty per cent of the sample shows a compact nuclear source and are classified as active galactic nucleus (AGN) candidates. The spectral analysis indicates that best fits involve a composite model: 1) absorbed primary continuum and 2) soft spectrum below 2 keV described by an absorbed scatterer and/or a thermal component. The resulting median spectral parameters and their standard deviations are $\langle\Gamma\rangle$ = 2.11 ± 0.52, $\langle kT\rangle$ = 0.54 ± 0.30 keV, ${\langle \log({\rm NH1}) \rangle }$ = 21.32 ${\pm}$ 0.71 and ${\langle \log({\rm NH2})\rangle }$ = 21.93 ${\pm}$ 1.36. We complement our X-ray results with an analysis of HST optical images and literature data on emission lines, radio compactness, and stellar population. After adding all these multiwavelength data, we conclude that evidence supports the AGN nature of their nuclear engine for 80% of the sample (66 out of 82 objects).
Post-Asymptotic Giant Branch Evolution of Low- and Intermediate-Mass Stars. Preliminary Results

Preliminary results from an ongoing project to compute a grid of post-AGB models is presented. Our preliminary results show that stellar evolution computations that include an updated treatment of the microphysics predict post-AGB timescales that are several times shorter that predicted by older models. Also the mass-luminosity relation of post-AGB models deviates from that of older grids. In addition, our results suggest only a slight metallicity dependence of the post-AGB timescales. We expect these results to have significant consequences for models of the formation of planetary nebulae and their luminosity function.
Difficulties experienced by South African adolescents during COVID-19 lockdown: implications for early mental health interventions

Adolescence is characterized as a period of great physical, psychological, social, and behavioral challenges which often impacts on the mental health of adolescents. Prior research has demonstrated the mental health of adolescents to be further complicated by the COVID-19 pandemic which resulted in isolation during the strictest lockdown period. As such, the primary purpose of this study was to identify the difficulties of South African adolescents during the COVID-19 pandemic. Data were collected through a questionnaire completed by 4230 grade 4 to 12 learners from two provinces in South Africa (Mpumalanga, North-West) and analyzed with chi-square, Cramer’s V, Bayesian, and the odds ratio tests. Participants self-reported on the difficulties they experienced during the strictest part of the COVID-19 lockdown period which could possibly impact on their mental health. The results indicate that fear was the most prominent difficulty experienced, but it must be viewed as a comorbidity with anxiety, stress, and depression. A significant finding was that the difficulties experienced were gender, age, and school level specific. The results indicate that mental health practitioners working with adolescents who experienced such difficulties should adopt a multilevel systems approach in supporting the mental health of adolescents during crisis situations like the lockdown during the COVID-19 pandemic. More importantly, early mental health interventions should take gender, age, and primary and secondary school levels into consideration for effectiveness since the difficulties highlighted in this study are likely to impact on the mental health of learners.
Phase-space representations of SIC-POVM fiducial states

Marcos Saraceno, 2 Leonardo Ermann, 3 and Cecilia Cormick Departamento de F́ısica Teórica, Comisión Nacional de Enerǵıa Atómica, Buenos Aires, Argentina Escuela de Ciencia y Tecnoloǵıa, Universidad Nacional de San Martin, San Martin, Argentina CONICET, Godoy Cruz 2290 (C1425FQB) CABA, Argentina IFEG, CONICET and Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina (Dated: December 8, 2016)
Ultrastrong adhesion in the contact with thin elastic layers on a rigid foundation

In the present short note, we generalize simple approximate Johnson-Jaffar-Barber solutions for the indentation by a rigid punch of a thin elastic layer on a rigid foundation to the case of adhesion. This could be an interesting geometry for an adhesive system, a limit case of the more general class of layered systems, or FGMs (Functionally Graded Materials). We show that ultrastrong adhesion (up to theoretical strength) can be reached both in line contact or in axisymmetric contact for thin layers (typically of nanoscale size), which suggests a new possible strategy for "optimal adhesion". In particular, in line contact adhesion enhancement occurs as an increase of the actual pull-off force, while in axisymmetric case the latter is apparently very close to the classical JKR case. However, it appears in closer examination that also for axisymmetric case, the enhancement occurs by reducing the size of contact needed to sustain the pull-off force. These effects are further enhanced by Poisson's ratio effects in the case of nearly incompressible layer.
Bang’s problem and symplectic invariants

We consider the Tarski--Bang problem about covering of convex bodies by planks. The results of this kind give a lower bound on the sum of widths of planks (regions between a pair of parallel hyperplanes) covering a given convex body. Previously we have applied some notions of symplectic geometry to study convex bodies, and here we show that the symplectic techniques may be useful in this problem as well. We are able to handle some particular cases with the symplectic techniques, and show that the general cases would follow from a certain ``subadditivity conjecture'' in symplectic geometry, motivated by the results of K. ~Ball. We also prove several related results by more elementary methods.
Subconvexity for symmetric square $L$-functions

Let $f$ be a holomorphic modular form of prime level $p$ and trivial nebentypus. We show that there exists a computable $\delta>0$, such that $$ L\left(\tfrac{1}{2},\mathrm{Sym}^2 f\right)\ll p^{\tfrac{1}{2}-\delta}, $$ with the implied constant depending only on $\delta$ and the weight of $f$.
The Systemic Immune-Inflammation Index and Predicting Cardiac Implantable Electronic Device Infections

This study aimed to evaluate the utility of the systemic immune-inflammation index (SII) in predicting the development of Cardiac Implantable Electronic Device (CIED) infections. A retrospective analysis was performed using the medical records of 2185 patients who underwent CIED (including de novo, revision, or upgrade) implantation at our institution from January 2012 to December 2019. We recorded CIED infections and risk factors according to the patient, device, and procedural characteristics during the median 28.7 months (6.2–56.8) follow-up. CIED infections were identified in 52 patients. Diabetes, chronic renal disease, SII before implantation, new cardiac resynchronization therapy (CRT) implantation, CRT-battery replacement, revision or upgrade, and the number of previous procedures were independent predictors of CIED infections. The area under the curve (AUC) of SII to predict CIED infection was . 733 (95% CI: .654-.811). A raised SII may be a useful predictor of CIED infection.
Computation of the chiral condensate using $N_f=2$ and $N_f=2+1+1$ dynamical flavors of twisted mass fermions

We apply the spectral projector method, recently introduced by Giusti and L\"uscher, to compute the chiral condensate using $N_f=2$ and $N_f=2+1+1$ dynamical flavors of maximally twisted mass fermions. We present our results for several quark masses at three different lattice spacings which allows us to perform the chiral and continuum extrapolations. In addition we report our analysis on the $O(a)$ improvement of the chiral condensate for twisted mass fermions. We also study the effect of the dynamical strange and charm quarks by comparing our results for $N_f=2$ and $N_f=2+1+1$ dynamical flavors.
The complete chloroplast genome sequence of Michelia macclurei (Dandy, 1928) (Magnoliaceae), an important fire-resistant tree species

Abstract Michelia macclurei (Dandy, 1928) is an evergreen broad-leaved tree species native to South China. This species has great ecological and economic importance. However, the genomic study of M. macclurei has lagged far behind. Here, we reported the complete chloroplast genome sequence of M. macclurei. The chloroplast genome size of M. macclurei was 160,139 bp, consisting of a pair of inverted repeat (IR) regions (26,575 bp), which was separated by a large single copy (LSC) region (88,167 bp) and a small single copy (SSC) region (18,822 bp). A total of 113 unique genes were annotated, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. The overall GC content was 39.2%. Phylogenetic analysis based on 16 whole chloroplast genome sequences of Michelia species suggested that M. macclurei and M. maudiae are sister to each other, and jointly sister to M. chapensis.
Gluino polarization at the LHC

Gluinos are produced pairwise at the LHC in quark-antiquark and gluon-gluon collisions: qq, gg{yields}g-tildeg-tilde. While the individual polarization of gluinos vanishes in the limit in which the small mass difference between L and R squarks of the first two generations is neglected, nonzero spin-spin correlations are predicted within gluino pairs. If the squark/quark charges in Majorana gluino decays are tagged, the spin correlations have an impact on the energy and angular distributions in reconstructed final states. On the other hand, the gluino polarization in single gluino production in the supersymmetric Compton process gq{yields}g-tildeq-tilde{sub R,L} is predicted to be nonzero, and the polarization affects the final-state distributions in super-Compton events.
Velocity spectra of quantum turbulence: experiments, numerics and models

Superfluid Turbulence is unusual and presents a challenge to fluid dynamicists because it consists of two coupled, inter penetrating turbulent fluids: the first is inviscid with quantised vorticity, the second is viscous with continuous vorticity. Despite this double nature, the observed spectra of the superfluid turbulent velocity at sufficiently large length scales are similar to those o ordinary turbulence. We present experimental, numerical and theoretical results which explain these similarities, and illustrate the limits of our present understanding of superfluid turbulence at smaller scales.
Photon Spheres and Sonic Horizons in Black Holes from Supergravity and Other Theories

We study closed photon orbits in spherically symmetric static solutions of supergravity theories, a Horndeski theory, and a theory of quintessence. These orbits lie in what we shall call a photon sphere (antiphoton sphere) if the orbit is unstable (stable). We show that in all the asymptotically flat solutions we examine that admit a regular event horizon, and whose energy-momentum tensor satisfies the strong energy condition, there is one and only one photon sphere outside the event horizon. We give an example of a Horndeski theory black hole (whose energy-momentum tensor violates the strong energy condition) whose metric admits both a photon sphere and an antiphoton sphere. The uniqueness and nonexistence also holds for asymptotically anti\char21{}de Sitter solutions in gauged supergravity. The latter also exhibits the projective symmetry that was first discovered for the Schwarzschild\char21{}de Sitter metrics: the unparametrized null geodesics are the same as when the cosmological or gauge coupling constant vanishes. We also study the closely related problem of accretion flows by perfect fluids in these metrics. For a radiation fluid, Bondi's sonic horizon coincides with the photon sphere. For a general polytropic equation of state this is not the case. Finally we exhibit counterexamples to a conjecture of Hod's.
EXTREMELY LARGE AND HOT MULTILAYER KEPLERIAN DISK AROUND THE O-TYPE PROTOSTAR W51N: THE PRECURSORS OF THE HCH ii REGIONS?

We present sensitive high angular resolution (0.″57–0.″78) SO, SO2, CO, C2H5OH, HC3N, and HCOCH2OH line observations at millimeter and submillimeter wavelengths of the young O-type protostar W51 North made with the Submillimeter Array. We report the presence of a large (about 8000 AU) and hot molecular circumstellar disk around this object, which connects the inner dusty disk with the molecular ring or toroid reported recently and confirms the existence of a single bipolar outflow emanating from this object. The molecular emission from the large disk is observed in layers with the transitions characterized by high excitation temperatures in their lower energy states (up to 1512 K) being concentrated closer to the central massive protostar. The molecular emission from those transitions with low or moderate excitation temperatures is found in the outermost parts of the disk and exhibits an inner cavity with an angular size of around 0. ″7. We modeled all lines with a local thermodynamic equilibrium (LTE) synthetic spectrum. A detailed study of the kinematics of the molecular gas together with an LTE model of a circumstellar disk shows that the innermost parts of the disk are also Keplerian plus a contracting velocity. The emission of the HCOCH2OH reveals the possible presence of a warm “companion” located to the northeast of the disk, however its nature is unclear. The emission of the SO and SO2 is observed in the circumstellar disk as well as in the outflow. We suggest that the massive protostar W51 North appears to be in a phase before the presence of a hypercompact or an ultracompact H ii (HC/UCH ii) region and propose a possible sequence on the formation of the massive stars.
Dependence of a quantum-mechanical system on its own initial state and the initial state of the environment it interacts with

We present a unifying framework to the understanding of when and how quantum-mechanical systems become independent of their initial conditions and adapt macroscopic properties (like temperature) of the environment. By viewing this problem from a quantum information theory perspective, we are able to simplify it in a very natural and easy way. We first show that for any interaction between the system and the environment, and almost all initial states of the system, the question of how long the system retains memory of its initial conditions can be answered by studying the temporal evolution of just one special initial state. This special state thereby depends only on our knowledge of macroscopic parameters of the system. We provide a simple entropic inequality for this state that can be used to determine whether most states of the system have or have not become independent of their initial conditions after time $t$. We discuss applications of our entropic criterion to thermalization times in systems with an effective light cone and to quantum memories suffering depolarizing noise. We make a similar statement for almost all initial states of the environment and finally provide a sufficient condition for which a system never thermalizes but remains close to its initial state for all times.