Miracle-dz/UniFAR-FTUs huggingface dataset:
A New Structural Phase Field Crystal Approach for Modelling Graphene

This paper introduces a new structural phase field crystal (PFC) type model that expands the PFC methodology to a wider class of structurally complex crystal structures than previously possible. Specifically, our new approach allows for stabilization of graphene, as well as its coexistence with a disordered phase. It also preserves the ability to model the usual triangular and square lattices previously reported in 2D PFC studies. Our approach is guided by the formalism of classical field theory, wherein the the free energy functional is expanded to third order in PFC density correlations. It differs from previous PFC approaches in two main features. First, it utilizes a hard-sphere repulsion to describe two-point correlations. Second, and more important, is that it uses a rotationally invariant three-point correlation function that provides a unified way to control the formation of crystalline structures that can be described by a specific bond angle, such as graphene, triangular or square symmetries. Our new approach retains much of the computational simplicity of previous PFC models and allows for efficient simulation of nucleation and growth of polycrystalline 2D materials. In preparation for future applications, this paper details the mathematical derivation of the model and its equilibrium properties, and uses dynamical simulations to demonstrate defect structures produced by the model.
Detection of the 128-day radial velocity variations in the supergiant α Persei - Rotational modulations, pulsations, or a planet?

Aims. In order to search for and study the nature of the low-amplitude and long-periodic radial velocity (RV) variations of massive stars, we have been carrying out a precise RV survey for supergiants that lie near or inside the Cepheid instability strip. Methods. We have obtained high-resolution spectra of α Per (F5 Ib) from November 2005 to September 2011 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory (BOAO). Results. Our measurements reveal that α Per shows a periodic RV variation of 128 days and a semi-amplitude of 70 m s −1 . We find no strong correlation between RV variations and bisector velocity span (BVS), but the 128-d peak is indeed present in the BVS variations among several other significant peaks in periodogram. Conclusions. α Per may have an exoplanet, but the combined data spanning over 20 years seem to suggest that the 128-d RV variations have not been stable on a long-term scale, which is somewhat difficult to reconcile with the exoplanet explanation. We do not exclude the pulsational nature of the 128-d variations in α Per. Although we do not find clear evidence for surface activity or rotational modulations by spots, coupled with the fact that the expected rotation period is ∼130 days the rotational modulation seems to be the most likely cause of the RV variations. More observational data and research are needed to clearly determine the origin of the RV variations in α Per.
SUPERMASSIVE POPULATION III SUPERNOVAE AND THE BIRTH OF THE FIRST QUASARS

The existence of supermassive black holes as early as z ∼ 7 is one of the great, unsolved problems in cosmological structure formation. One leading theory argues that they are born during catastrophic baryon collapse in z ∼ 15 protogalaxies that form in strong Lyman–Werner UV backgrounds. Atomic line cooling in such galaxies fragments baryons into massive clumps that are thought to directly collapse to 104–105 M☉ black holes. We have now discovered that some of these fragments can instead become supermassive stars that eventually explode as thermonuclear supernovae (SNe) with energies of ∼1055 erg, the most energetic explosions in the universe. We have calculated light curves and spectra for supermassive Pop III SNe with the Los Alamos RAGE and SPECTRUM codes. We find that they will be visible in near-infrared all-sky surveys by Euclid out to z ∼ 10–15 and by WFIRST and WISH out to z ∼ 15–20, perhaps revealing the birthplaces of the first quasars.
Reliability of Home Sleep Apnea Testing for Diagnosing Obstructive Sleep Apnea in Patients With Spontaneous Cerebrospinal Fluid Leaks

Study Objectives: To establish the prevalence of obstructive sleep apnea (OSA) in patients with spontaneous cerebrospinal fluid (sCSF) leaks and demonstrate the reliability of home sleep apnea testing (HSAT) to screen for OSA in this population. Methods: A literature review was performed to assess data on OSA prevalence in sCSF leaks. An institutional retrospective review was performed of 20 patients with sCSF leaks who met inclusion criteria. Patients without prior sleep studies were prospectively administered sleep studies, either HSAT or polysomnogram (PSG). Results: Twenty patients met the inclusion criteria. Two patients had prior sleep studies while 18 patients obtained prospective sleep studies following diagnosis and prior to management of sCSF leaks. Nineteen patients (95%) had evidence of mild or greater OSA. Conclusions: This study re-demonstrates the high prevalence of OSA in patients with sCSF leaks, consistent with current literature, and investigates the reliability of HSAT for diagnosis of OSA in this population.
Root resorption followed by orthodontic treatment in individuals with anterior open bite. A complete vision focused on different treatment alternatives: A review

ABSTRACT The aim of this review was to determine the incidence of different types of treatment and the prevalence of root resorption in incisors induced by orthodontic treatment in patients with open bite. Libraries and electronic databases were searched, with 322 articles being selected and 55 articles considered regarding PRISMA checklist. It has been shown that apical root resorption of the incisors is more frequent in patients with premolar extractions than in those treated without extractions, due to greater apical displacement during retraction of the anterior teeth in the space closure phase. On the other hand, it has been described that intrusion of posterior teeth is four times more likely to cause root resorption than extrusion movement, thereby increasing the risk of root resorption in posterior teeth compared to conventional orthodontic treatment not requiring molar intrusions. Finally, aligners, such as orthodontic treatments with fixed appliances, have not been shown to induce clinically significant root resorption in open bite individuals. Literature on root resorption in open bite treatments is scarce making difficult conclusions difficult. However, the amount of root loss in cases of open bite seems to be similar to that of individuals without open bite.
Composition and evolution of interstellar grain mantle under the effects of photodissociation

We studied the chemical evolution of interstellar grain mantle by varying the physical parameters of the interstellar medium (ISM). To mimic the actual interstellar condition, gas–grain interactions via accretion from the gas phase and desorption (thermal evaporation and photoevaporation) from the grain surface were considered. We found that the chemical composition of the interstellar grain mantle is highly dependent on the physical parameters associated with molecular cloud. Interstellar photons have been found to play an important role in the growth and structure of the interstellar grain mantle. We considered the effects of interstellar photons (photodissociation and photoevaporation) in our simulation under various interstellar conditions. We noticed that the effects of interstellar photons dominate around the region of lower visual extinction. These photons contribute significantly to the formation of the grain mantle. The energy of the incoming photon is attenuated by the absorption and scattering by the interstellar dust. The topmost layers are assumed to be affected mainly by the incoming radiation. We have studied the effects of photodissociation by varying the number of layers which could be affected by it. Model calculations were carried out for the static (extinction parameter is changing with the density of the cloud) as well as the time-dependent case (i.e. both extinction parameter and number density of the cloud are changing with time) and the results are discussed in detail. Different routes to the formation of water molecules have been studied and it has been noticed that production of water molecules via O3 and H2O2 contributes significantly around the dense region. At the end, various observational evidences for the condensed phase species are summarized with their physical conditions and are compared with our simulation results.
Phase-field-crystal study of grain boundary premelting and shearing in bcc iron

We use the phase-field-crystal (PFC) method to investigate the equilibrium premelting and nonequilibrium shearing behaviors of $[001]$ symmetric tilt grain boundaries (GBs) at high homologous temperature over the complete range of misorientation $0<\theta<90^\circ$ in classical models of bcc Fe. We characterize the dependence of the premelted layer width $W$ as a function of temperature and misorientation and compute the thermodynamic disjoining potential whose derivative with respect to $W$ represents the structural force between crystal-melt interfaces due to the spatial overlap of density waves. The disjoining potential is also computed by molecular dynamics (MD) simulations, for quantitative comparison with PFC simulations, and coarse-grained amplitude equations (AE) derived from PFC that provide additional analytical insights. We find that, for GBs over an intermediate range of misorientation ($\theta_{\rm min}<\theta<\theta_{\rm max}$), $W$ diverges as the melting temperature is approached from below, corresponding to a purely repulsive disjoining potential, while for GBs outside this range ($\theta<\theta_{\rm min}$ or $\theta_{\rm max}<\theta<90^\circ$), $W$ remains finite at the melting point, with its value corresponding to a shallow attractive minimum of the disjoining potential. In response to a shear stress parallel to the GB plane, GBs in PFC simulations exhibit coupled motion normal to this plane, with a discontinuous change of the coupling factor as a function of $\theta$ that reflects a transition between two coupling modes, and/or sliding (shearing of the two grains). The coupling factor for the two coupling modes is in excellent quantitative agreement with previous theoretical predictions [J. W. Cahn, Y. Mishin, and A. Suzuki, Acta Mater. 54, 4953 (2006)].
Slicing the Torus: Obscuring Structures in Quasars

Quasars and Active Galactic Nuclei (AGNs) are often obscured by dust and gas. It is normally assumed that the obscuration occurs in an oblate "obscuring torus", that begins at the radius at which the most refractive dust can remain solid. The most famous form of this torus is a donut-shaped region of molecular gas with a large scale-height. While this model is elegant and accounts for many phenomena at once, it does not hold up to detailed tests. Instead the obscuration in AGNs must occur on a wide range of scales and be due to a minimum of three physically distinct absorbers. Slicing the "torus" into these three regions will allow interesting physics of the AGN to be extracted.
Mental Health and Substance Use in NCAA Athletes in the Context of the COVID-19 Pandemic and Lockdown

Background Although the coronavirus disease 2019 (COVID-19) pandemic had pervasive effects on the lives of individuals, its influence on the mental health of collegiate athletes remains unknown. This study aimed to assess changes in mental health and substance use in National Collegiate Athlete Association (NCAA) Division I athletes in Southern California during the COVID-19 pandemic. Methodology An online survey was created using the Qualtrics software (Qualtrics, Provo, Utah). NCAA Division I athletes in Southern California completed preseason surveys querying indices of mental health, substance use, and injury in the year before the COVID-19 pandemic (March 2019 to March 2020) and during the pandemic (March 2020 to March 2021). The athletes filled out the survey from June 2021 to September 2021. Participants were asked how likely they were to agree with the following statements: I have felt physically prepared for athletic competitions, I have been satisfied with my mental health, and I have had adequate sleep. Participants were also asked to compare their substance use between the two time periods. Sociodemographic information regarding participants’ age, gender, sports team, as well as year in sport and school was also collected. Group comparison analyses were performed using Fisher’s exact test. Correlations between mental health measures and other variables were examined using Spearman’s correlation coefficients. Results A total of 189 athletes completed the survey (out of the 259 surveys that were started). Females were significantly less likely to feel satisfied with mental health (p < 0.01) and physically prepared for sport (p < 0.01). Across all respondents, satisfaction with mental health was positively correlated with adequate sleep (p < 0.01) and physical preparedness for sport (p < 0.01) and negatively correlated with injury (p < 0.05). There was no significant correlation between mental health status and history of COVID-19 infection (p = 0.84). The vast majority of athletes reported no significant change in substance use pre- to post-pandemic, with no differences according to sex. Conclusions The COVID-19 pandemic had a differential impact on the mental health of female versus male NCAA athletes. Mental health was correlated with sleep, physical preparedness, and being injury-free but not with a history of COVID-19 infection. Despite reports indicating increased substance use in the general population, athletes in this group reported no change in licit and illicit substance use.
A FIRST APPLICATION OF THE ALCOCK–PACZYNSKI TEST TO STACKED COSMIC VOIDS

We report on the first application of the Alcock–Paczynski test to stacked voids in spectroscopic galaxy redshift surveys. We use voids from the Sutter et al. void catalog, which was derived from the Sloan Digital Sky Survey Data Release 7 main sample and luminous red galaxy catalogs. The construction of that void catalog removes potential shape measurement bias by using a modified version of the ZOBOV algorithm and by removing voids near survey boundaries and masks. We apply the shape-fitting procedure presented in Lavaux & Wandelt to 10 void stacks out to redshift z = 0.36. Combining these measurements, we determine the mean cosmologically induced “stretch” of voids in three redshift bins, with 1σ errors of 5%–15%. The mean stretch is consistent with unity, providing no indication of a distortion induced by peculiar velocities. While the statistical errors are too large to detect the Alcock–Paczynski effect over our limited redshift range, this proof-of-concept analysis defines procedures that can be applied to larger spectroscopic galaxy surveys at higher redshifts to constrain dark energy using the expected statistical isotropy of structures that are minimally affected by uncertainties in galaxy velocity bias.
Superconducting Antenna Concept for Gravitational Wave Radiation

We present an idea for detecting gravitational waves (GWs) by measuring the current induced in a superconducting loop by the rotation of a frame to which it is attached. The frame experiences a torque caused by a GW propagating perpendicular to it because it is made of materials of different density in adjacent quadrants. Superconducting Cooper pair system responds symmetrically to the wave and stays at rest, while the ions of the superconductor are being accelerated by the moving frame. This generates an electric current in the loop which can be measured precisely by sensitive electronics. For that task the antenna consists of two superconducting loops parallel to each other. One of them, the primary loop, rotationally oscillates because of the described reasons, while the second stays at rest. In the oscillating loop the current creates an oscillating magnetic flux. This flux should be compensated due to fluxoid quantization, by the oppositely directed current in the non-moving, secondary loop, in which the ions are at rest, and the Cooper pairs move. We estimate the resulting signal/noise ratio and discuss the signal detectability. Several designs are envisioned, both for terrestrial and for orbital arrangements of the antenna.
Constraints on low-mass WIMPs from the EDELWEISS-III dark matter search

We present the results of a search for elastic scattering from galactic dark matter in the form of Weakly Interacting Massive Particles (WIMPs) in the 4–30 GeV/c2 mass range. We make use of a 582 kg-day fiducial exposure from an array of 800 g Germanium bolometers equipped with a set of interleaved electrodes with full surface coverage. We searched specifically for ∼ 2.5–20 keV nuclear recoils inside the detector fiducial volume. As an illustration the number of observed events in the search for 5 (resp. 20) GeV/c2 WIMPs are 9 (resp. 4), compared to an expected background of 6.1 (resp. 1.4). A 90% CL limit of 4.3 × 10−40 cm2 (resp. 9.4 × 10−44 cm2) is set on the spin-independent WIMP-nucleon scattering cross-section for 5 (resp. 20) GeV/c2 WIMPs. This result represents a 41-fold improvement with respect to the previous EDELWEISS-II low-mass WIMP search for 7 GeV/c2 WIMPs. The derived constraint is in tension with hints of WIMP signals from some recent experiments, thus confirming results obtained with different detection techniques.
Nb nano superconducting quantum interference devices with high spin sensitivity for operation in magnetic fields up to 0.5 T

We investigate electric transport and noise properties of microstrip-type submicron direct current superconducting quantum interference devices (dc SQUIDs) based on Nb thin films and overdamped Josephson junctions with a HfTi barrier. The SQUIDs were designed for optimal spin sensitivity Sμ1/2 upon operation in intermediate magnetic fields B (tens of mT), applied perpendicular to the substrate plane. Our, so far, best SQUID can be continuously operated in fields up to B≈±50 mT with rms flux noise SΦ,w1/2≤250 nΦ0/Hz1/2 in the white noise regime and spin sensitivity Sμ1/2≤29 μB/Hz1/2. Furthermore, we demonstrate operation in B = 0.5 T with high sensitivity in flux SΦ,w1/2≈680 nΦ0/Hz1/2 and in electron spin Sμ1/2≈79 μB/Hz1/2. We discuss strategies to further improve the nanoSQUID performance.
Statistical mechanics of unbound two-dimensional self-gravitating systems

We study, using both theory and molecular dynamics simulations, the relaxation dynamics of a microcanonical two-dimensional self-gravitating system. After a sufficiently large time, a gravitational cluster of N particles relaxes to the Maxwell–Boltzmann distribution. The time taken to reach the thermodynamic equilibrium, however, scales with the number of particles. In the thermodynamic limit, at fixed total mass, an equilibrium state is never reached and the system becomes trapped in a non-ergodic stationary state. An analytical theory is presented which allows us to quantitatively describe this final stationary state, without any adjustable parameters.
String field theory solution corresponding to constant background magnetic field

Following the method recently proposed by Erler and Maccaferri, we construct solutions to the equation of motion of Witten's cubic string field theory, which describe constant magnetic field background. We study the boundary condition changing operators relevant to such background and calculate the operator product expansions of them. We obtain solutions whose classical action coincide with the Born-Infeld action.
SELF-SIMILAR DYNAMICAL RELAXATION OF DARK MATTER HALOS IN AN EXPANDING UNIVERSE

We investigate the structure of cold dark matter halos using advanced models of spherical collapse and accretion in an expanding universe. These are based on solving time-dependent equations for the moments of the phase-space distribution function in the fluid approximation; our approach includes non-radial random motions and, most importantly, an advanced treatment of both dynamical relaxation effects that take place in the infalling matter: phase-mixing associated with shell crossing and collective collisions related to physical clumpiness. We find self-similar solutions for the spherically averaged profiles of mass density ρ(r), pseudo phase-space density Q(r), and anisotropy parameter β(r). These profiles agree with the outcomes of state-of-the-art N-body simulations in the radial range currently probed by the latter; at smaller radii, we provide specific predictions. In the perspective provided by our self-similar solutions, we link the halo structure to its two-stage growth history and propose the following picture. During the early fast collapse of the inner region dominated by a few merging clumps, efficient dynamical relaxation plays a key role in producing closely universal mass density and pseudo phase-space density profiles; in particular, these are found to depend only weakly on the detailed shape of the initial perturbation and the related collapse times. The subsequent inside-out growth of the outer regions feeds on the slow accretion of many small clumps and diffuse matter; thus the outskirts are only mildly affected by dynamical relaxation but are more sensitive to asymmetries and cosmological variance.
Phase transitions and connectivity in three-dimensional vortex equilibria

The statistical mechanics of collections of closed self avoiding vortex loops on a lattice are studied. The system is related to the vortex form of the three dimensional XY model and to lattice vortex equilibrium models of turbulence. The system exhibits vortex connectivity and screening effects, and models in vorticity variables the superfluid transition. The equilibrium states of the system are simulated by a grand canonical Monte Carlo method. A set of geometric transformations for self-avoiding loops is developed. The numerical method employs histogram sampling techniques and utilizes a modification to the Metropolis flow which enhances efficiency. Results are given for a region in the temperature-chemical potential plane, where the chemical potential is related to the vortex fugacity. A line of second order transitions is identified at low temperature. The transition is shown to be a percolation threshold at which connected vortex loops of infinite size appear in the system. The nature of the transition supports the assumption that the lambda transition in bulk superfluid helium is driven by vortices. An asymptotic analysis is performed for the energy and entropy scaling of the system as functions of the system size and the lattice spacing. These estimates indicate that the infinite more » temperature line is a phase boundary between small scale fractal vortices and large scale smooth vortices. A suggestion is made that quantum vortices have uniform structure on the scale of the lattice spacing and lie in the positive temperature regime, while classical vortices have uniform structure on the scale of the domain and lie in the negative temperature regime. « less
Novel mechanism for vorticity generation in black-hole accretion disks

Vorticity generation in accretion disks around Schwarzschild and Kerr black holes is investigated in the context of magnetofluid dynamics derived for both General Relativity (GR), and modified gravity formulations. In both cases, the Kerr geometry leads to a "stronger" generation of vorticity than its Schwarzschild counterpart. Of the two principal sources, the relativistic drive peaks near the innermost stable circular orbit (isco), whereas the baroclinic drive dominates at larger distances. Consequences of this new relativistic vorticity source are discussed in several astrophysical settings.