Miracle-dz/UniFAR-FTUs huggingface dataset:
Melting artificial spin ice

Artificial spin ice arrays of micromagnetic islands are a means of engineering additional energy scales and frustration into magnetic materials. Here we demonstrate a magnetic phase transition in an artificial square spin ice and use the symmetry of the lattice to verify the presence of excitations far below the ordering temperature. We do this by measuring the temperature-dependent magnetization in different principal directions and comparing it with simulations of idealized statistical mechanical models. Our results confirm a dynamical pre-melting of the artificial spin ice structure at a temperature well below the intrinsic ordering temperature of the island material. We thus create a spin ice array that has the real thermal dynamics of artificial spins over an extended temperature range.
STELLAR ENCOUNTER RATE IN GALACTIC GLOBULAR CLUSTERS

The high stellar densities in the cores of globular clusters cause significant stellar interactions. These stellar interactions can produce close binary mass-transferring systems involving compact objects and their progeny, such as X-ray binaries and radio millisecond pulsars. Comparing the numbers of these systems and interaction rates in different clusters drives our understanding of how cluster parameters affect the production of close binaries. In this paper we estimate stellar encounter rates (Γ) for 124 Galactic globular clusters based on observational data as opposed to the methods previously employed, which assumed “King-model” profiles for all clusters. By deprojecting cluster surface brightness profiles to estimate luminosity density profiles, we treat “King-model” and “core-collapsed” clusters in the same way. In addition, we use Monte Carlo simulations to investigate the effects of uncertainties in various observational parameters (distance, reddening, surface brightness) on Γ, producing the first catalog of globular cluster stellar encounter rates with estimated errors. Comparing our results with published observations of likely products of stellar interactions (numbers of X-ray binaries, numbers of radio millisecond pulsars, and γ-ray luminosity) we find both clear correlations and some differences with published results.
Seeking Lorentz Violation from the Higgs

The recently discovered Higgs particle with a mass near 126 GeV presents new opportunities to explore Lorentz violation. Ultra-high-energy cosmic rays are one of the most sensitive testing grounds for Lorentz symmetry, and can be used to seek for and limit departures from Lorentz invariance in the Higgs sector. If the Higgs were to have a super- or sub-luminal maximal speed both Higgs and weak interaction physics would be modified. Consideration of such modifications allow us to constrain the Higgs maximal velocity to agree with that of other Standard Model particles to parts in 10 14 .
Trapping centers at the superfluid-Mott-insulator criticality: Transition between charge-quantized states

Under the conditions of superfluid-Mott-insulator criticality in two dimensions, the trapping centers--i.e., local potential wells and bumps--are generically characterized by an integer charge corresponding to the number of trapped particles (if positive) or holes (if negative). Varying the strength of the center leads to a transition between two competing ground states with charges differing by $\pm 1$. The hallmark of the transition scenario is a splitting of the number density distortion, $\delta n(r)$, into a half-integer core and a large halo carrying the complementary charge of $\pm 1/2$. The sign of the halo changes across the transition and the radius of the halo, $r_0$, diverges on the approach to the critical strength of the center, $V = V_c$, by the law $r_0 \propto |V-V_c|^{-\tilde{\nu}}$, with $\tilde{\nu} \approx 2.33(5)$.
Sepsis-Related Mortality Rates and Trends Based on Site of Infection

OBJECTIVES: Sepsis is defined as life-threatening organ dysfunction triggered by an underlying infection. A recent study noted that the overall sepsis-related mortality rate in the United States is stable. In this study, we evaluated the sepsis-related mortality rates and trends associated with the three most common sites of infection. DESIGN: Retrospective population-based study. SETTING: Multiple Cause of Death (MCOD) database available through the Centers for Disease Control and Prevention website. PATIENTS: Decedents with sepsis-related deaths and the source of sepsis were identified using previously validated International Classification of Diseases codes. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: From 2004 to 2018, using the MCOD, the age-adjusted mortality rate per 1,000,000 population from pulmonary sepsis was 111.8, from abdominal sepsis was 46.7, and from genitourinary sepsis was 52. Mortality rates from all three sites increased. Males had a higher mortality rate from pulmonary sepsis and abdominal sepsis and lower mortality rate from genitourinary sepsis. Black and Native American decedents had the highest mortality rates from all three sepsis sites. Compared with White decedents, Hispanic decedents had a higher mortality rate from pulmonary sepsis but lower rate from genitourinary sepsis. Asian decedents had the lowest mortality rates from abdominal and genitourinary sepsis but similar mortality rates from pulmonary sepsis as White decedents. The mortality rate increased in White and Native American decedents for all three sepsis sites, whereas in Hispanic decedents only abdominal and genitourinary sites increased, and in Black and Asian decedents only abdominal sepsis rates increased. CONCLUSIONS: Despite the overall stable sepsis-related mortality rates, the rates secondary to pulmonary, abdominal, and genitourinary sepsis are increasing in both sexes and all age groups. This is likely due to improved identification/documentation of a site of infection in patients with sepsis. We noted significant racial variation in mortality rates/trends, which should be considered in future studies.
Stable Exact Cosmological Solutions in Induced Gravity Models

We study dynamics of induced gravity cosmological models with the sixth degree polynomial potentials, that have found using the superpotential method. The important property of these models are existence of exact cosmological solutions that tend to fixed points. The stability of these cosmological solutions have been obtained. In particular, we find conditions under which solutions with a non-monotonic Hubble parameter that tend to a fixed point are attractors.
Statistical-analysis of Spectra From Electron-spectroscopy for Chemical-analysis

Electron spectroscopy for chemical analysis is a key technique in the study of modified material surfaces. Analysis of the resulting spectra consists in decomposing multiple peaks into subpeaks, whose functional form is known up to a few parameters. Statistical inference consists in estimating these parameters and derived quantities, such as peak area ratios, and in assessing the accuracies of these estimates. Purely likelihood-based peak decomposition is notorious for problems of identifiability. In practice, however, additional knowledge exists about some of the parameters and can, when incorporated in the model as an informative prior, produce unique decompositions. Modem tools for Bayesian statistics, such as profile diagnostics, Laplacian approximations of marginals and Markov chain algorithms for sampling from the posterior, can then be used to obtain inference reaching beyond point estimates and approximate standard errors.
Role of Omega-6 Fatty Acid Metabolism in Cardiac Surgery Postoperative Bleeding Risk

OBJECTIVES: Cardiac surgery is frequently associated with significant postoperative bleeding. Platelet-dysfunction is the main cardiopulmonary bypass (CPB)-induced hemostatic defect. Not only the number of platelets decreases, but also the remaining are functionally impaired. Although lipid metabolism is crucial for platelet function, little is known regarding platelet metabolic changes associated with CPB-dysfunction. Our aim is to explore possible contribution of metabolic perturbations for platelet dysfunction after cardiac surgery. DESIGN: Prospective cohort study. SETTING: Tertiary academic cardiothoracic-surgery ICU. PATIENTS: Thirty-three patients submitted to elective surgical aortic valve replacement. INTERVENTIONS: Samples from patients were collected at three time points (preoperative, 6- and 24-hr postoperative). Untargeted metabolic analysis using high-performance liquid chromatography-tandem mass spectrometry was performed to compare patients with significant postoperative bleeding with patients without hemorrhage. Principal component analyses, Wilcoxon matched-pairs signed-rank tests, adjusted to FDR, and pairwise comparison were used to identify pathways of interest. Enrichment and pathway metabolomic complemented the analyses. MEASUREMENTS AND MAIN RESULTS: We identified a platelet-related signature based on an overrepresentation of changes in known fatty acid metabolism pathways involved in platelet function. We observed that arachidonic acid (AA) levels and other metabolites from the pathway were reduced at 6 and 24 hours, independently from antiagreggation therapy and platelet count. Concentrations of preoperative AA were inversely correlated with postoperative chest tube blood loss but were not correlated with platelet count in the preoperative, at 6 or at 24 hours. Patients with significant postoperative blood-loss had considerably lower values of AA and higher transfusion rates. Values of postoperative interleukin-6 were strongly correlated with AA variability. CONCLUSIONS AND RELEVANCE: Our observations suggest that an inflammatory-related perturbation of AA metabolism is a signature of cardiac surgery with CPB and that preoperative levels of AA may be more relevant than platelet count to anticipate and prevent postoperative blood loss in patients submitted to cardiac surgery with CPB.
Nonperturbative enhancement of heavy quark-pair production in a strong SU(2) color field

Nonperturbative charm and bottom quark-pair production is investigated in the early stage of heavy-ion collisions. The time-dependent study is based on a kinetic description of fermion-pair production in strong non-Abelian fields. We introduce a time-dependent chromo-electric external field with a pulselike time evolution to simulate the overlap of two colliding heavy ions. The calculations is performed in a SU(2) color model with finite current quark masses. Yields of heavy quark pairs are compared to the ones of light and strange quark pairs. We show that the small inverse duration time of the field pulse determines the efficiency of the quark-pair production. The expected suppression for heavy quark production, as follows from the Schwinger formula for a constant field, is not seen, but rather an enhanced heavy quark production appears at ultrarelativistic energies.
An analysis method for transmission measurements of superconducting resonators with applications to quantum-regime dielectric-loss measurements

Superconducting resonators provide a convenient way to measure loss tangents of various dielectrics at low temperature. For the purpose of examining the microscopic loss mechanisms in dielectrics, precise measurements of the internal quality factor at different values of energy stored in the resonators are required. Here, we present a consistent method to analyze a LC superconducting resonator coupled to a transmission line. We first derive an approximate expression for the transmission S-parameter S21(ω), with ω the excitation frequency, based on a complete circuit model. In the weak coupling limit, we show that the internal quality factor is reliably determined by fitting the approximate form of S21(ω). Since the voltage V of the capacitor of the LC circuit is required to determine the energy stored in the resonator, we next calculate the relation between V and the forward propagating wave voltage Vin+, with the latter being the parameter controlled in experiments. Due to the dependence of the quality f.
Stabilization of a spatially non‐causal reaction–diffusion equation by boundary control

Stabilization of a reaction–diffusion equation, in which the heat source depends on the temperature of the whole space, is considered by using boundary control. A new backstepping transformation is introduced, in which there are two kernels. Through a series of mathematical tricks, the exact solutions of kernels are obtained, and a control law is obtained specifically. The inverse transformation is derived, and stability of the closed loop system established. Simulation results show that the closed loop system is stable. Copyright © 2012 John Wiley & Sons, Ltd.
THE AFTERGLOW AND ENVIRONMENT OF THE SHORT GRB 111117A

We present multi-wavelength observations of the afterglow of the short GRB 111117A, and follow-up observations of its host galaxy. From rapid optical and radio observations, we place limits of r ≳ 25.5 mag at δt ≈ 0.55 days and Fν(5.8 GHz) ≲ 18 μJy at δt ≈ 0.50 days, respectively. However, using a Chandra observation at δt ≈ 3.0 days we locate the absolute position of the X-ray afterglow to an accuracy of 0. ″22 (1σ), a factor of about six times better than the Swift/XRT position. This allows us to robustly identify the host galaxy and to locate the burst at a projected offset of 1. ″25 ± 0. ″20 from the host centroid. Using optical and near-IR observations of the host galaxy we determine a photometric redshift of z = 1.3+0.3− 0.2, one of the highest for any short gamma-ray burst (GRB), leading to a projected physical offset for the burst of 10.5 ± 1.7 kpc, typical of previous short GRBs. At this redshift, the isotropic γ-ray energy is Eγ, iso ≈ 3.0 × 1051 erg (rest-frame 23–2300 keV) with a peak energy of Epk ≈ 850–2300 keV (rest-frame). In conjunction with the isotropic X-ray energy, GRB 111117A appears to follow our recently reported Ex, iso–Eγ, iso–Epk universal scaling. Using the X-ray data along with the optical and radio non-detections, we find that for a blastwave kinetic energy of EK, iso ≈ Eγ, iso erg, the circumburst density is n0 ≈ 3 × 10−4 − 1 cm−3 (for a range of ϵB = 0.001–0.1). Similarly, from the non-detection of a break in the X-ray light curve at δt ≲ 3 days, we infer a minimum opening angle for the outflow of θj ≳ 3–10° (depending on the circumburst density). We conclude that Chandra observations of short GRBs are effective at determining precise positions and robust host galaxy associations in the absence of optical and radio detections.
Ab-initio study of the effects induced by the electron-phonon scattering in carbon based nanostructures

In this paper we investigate from first principles the effect of the electron-phonon interaction in two paradigmatic nanostructures: trans-polyacetylene and polyethylene. We found that the strong electron-phonon interaction leads to the appearance of complex structures in the frequency dependent electronic self-energy. Those structures rule out any quasi-particle picture, and make the adiabatic and static approximations commonly used in the well-established Heine Allen Cardona (HAC) approach inadequate. We propose, instead, a fully ab-initio dynamical formulation of the problem within the Many Body Perturbation Theory framework. The present dynamical theory reveals that the structures appearing in the electronic self-energy are connected to the existence of packets of correlated electron/phonon states. These states appear in the spectral functions even at $T=0\,K$, revealing the key role played by the zero point motion effect. We give a physical interpretation of these states by disclosing their internal composition by mapping the Many Body problem to the solution of an eigenvalue problem.
Decontaminating Swift UVOT Grism Observations of Transient Sources

We present a new technique of decontaminating Swift Ultraviolet/Optical Telescope grism spectra for transient objects. We describe the template image requirements and image processing steps necessary to successfully implement the empirical decontamination technique. We demonstrate the accuracy of the flux and wavelength calibrations for decontaminated spectra by comparing a spectrum of SN 2011fe with a well-calibrated, long-slit ultraviolet spectrum from the Hubble Space Telescope’s Space Telescope Imaging Spectrograph. We also show how the decontamination removes spurious emission lines from spectra of iPTF14bdn that otherwise could be misinterpreted as coming from the supernova. The software that implements this technique is briefly discussed and is made available to the community.
Running title: IRON STRESS ON C. hololeuca AND C. papaya Academy Section: ECOSYSTEMS

Iron is essential to plant development. However, its excess can provoke an increase in reactive oxygen species and oxidative stress in plants. The objective of this work was to verify the effects of high concentrations of iron on the oxidative stress of seeds and young plants of Cecropia hololeuca and Carica papaya. The species were submitted to concentrations of 0.045, 4 and 8mM of iron in the form of ferrous sulfate and FeEDTA. The experiments of germination and initial growth took place in a growth chamber, with temperature of 25oC and 12h photoperiod. We performed the lipid peroxidation test by extraction and quantification of malonaldehyde and hydrogen peroxide. The application of iron did not cause a significant elevation in the contents of malonaldehyde and hydrogen peroxide in the germination of C. hololeuca and C. papaya. In the young plants, the hydrogen peroxide did not change in any of the treatments. However, it was possible to observe an expressive increase in malonaldehyde concentration in both species when exposed to FeEDTA 4 to 8mM. The results indicate a sensibility of C. hololeuca and C. papaya to high iron levels, amplifying the oxidative stress process that can harm their growth and initial development.
Ozone episodes in Catalonia during the summer of 2019. A meteorological and photochemical modeling analysis.

: During the summer of 2019 unusual exceedances of ozone concentration aﬀected Catalan territory. In the present work, a deep study of two ozone episodes is performed, focusing on the ﬂow circulation and potential sources. Episode A occurred on June 28 and June 29 and Episode B on July 23. Both episodes are characterized by synoptic anticyclonic conditions, surface temperatures over the 95th percentile and high ozone values recorded inland due to precursors advection (NO x and VOCs) mainly from Barcelona Metropolitan Area (AMB). The analysis of measured time series and the comparison with ARAMIS modeled concentrations showed that advection on June 28 and July 23 made its way through the eastern Barcelona valley and through the western one on June 29. Modeled-observation comparison maps reﬂect the general tendency of the model to overestimate modeled peak areas, to slightly underestimate in the rest of the territory and to rise ozone values few hours before they are measured. Moreover, a trajectory analysis conﬁrmed recirculation between June 28 and June 29 and concentration weighted trajectory maps determined the pathways linking the receptors with the AMB as the main potential sources for the cities of Vic and Manresa. Finally, NO 2 measured in Barcelona was found to have inﬂuence in urban and rural ozone concentrations.
THROUGH THE LOOKING GLASS: BRIGHT, HIGHLY MAGNIFIED GALAXY CANDIDATES AT z ∼ 7 BEHIND A1703

We report the discovery of seven strongly lensed Lyman-break galaxy (LBG) candidates at z ∼ 7 detected in Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging of A1703. The brightest candidate, called A1703-zD1, has an observed (lensed) magnitude of 24.0 AB (26σ) in the WFC3/IR F160W band, making it 0.2 mag brighter than the z850-dropout candidate recently reported behind the Bullet Cluster and 0.7 mag brighter than the previously brightest known z ∼ 7.6 galaxy, A1689-zD1. With a cluster magnification of ∼9, this source has an intrinsic magnitude of H160 = 26.4 AB, a strong z850 − J125 break of 1.7 mag, and a photometric redshift of z ∼ 6.7. Additionally, we find six other bright LBG candidates with H160-band magnitudes of 24.9–26.4, photometric redshifts z ∼ 6.4 − 8.8, and magnifications μ ∼ 3–40. Stellar population fits to the Advanced Camera for Surveys, WFC3/IR, and Spitzer/Infrared Array Camera data for A1703-zD1 and A1703-zD4 yield stellar masses (0.7 − 3.0) × 109 M☉, stellar ages 5–180 Myr, and star formation rates ∼7.8 M☉ yr−1, and low reddening with AV ⩽ 0.7. The source-plane reconstruction of the exceptionally bright candidate A1703-zD1 exhibits an extended structure, spanning ∼4 kpc in the z ∼ 6.7 source plane, and shows three resolved star-forming knots of radius r ∼ 0.4 kpc.
SOLAR FLARE COMPOSITION AND THERMODYNAMICS FROM RESIK X-RAY SPECTRA

Previous estimates of the solar flare abundances of Si, S, Cl, Ar, and K from the RESIK X-ray crystal spectrometer on board the CORONAS-F spacecraft were made on the assumption of isothermal X-ray emission. We investigate the effect on these estimates by relaxing this assumption and instead determining the differential emission measure (DEM) or thermal structure of the emitting plasma by re-analyzing RESIK data for a GOES class M1.0 flare on 2002 November 14 (SOL2002-11-14T22:26) for which there was good data coverage. The analysis method uses a maximum-likelihood (Withbroe–Sylwester) routine for evaluating the DEM. In a first step, called here AbuOpt, an optimized set of abundances of Si, S, Ar, and K is found that is consistent with the observed spectra. With these abundances, the DEM evolution during the flare is found. The abundance optimization leads to revised abundances of silicon and sulfur in the flare plasma: A(S) = 6.94 ± 0.06 and A(Si) = 7.56 ± 0.08 (on a logarithmic scale with A(H) = 12). Previously determined abundances of Ar, K, and Cl from an isothermal assumption are still the preferred values. During the flare's maximum phase, the X-ray-emitting plasma has a basically two-temperature structure, with the cooler plasma with approximately constant temperature (3–6 MK) and a hotter plasma with temperature 16–21 MK. Using imaging data from the RHESSI hard X-ray spacecraft, the emission volume of the hot plasma is deduced from which lower limits of the electron density Ne and the thermal content of the plasma are given.
Two-loop renormalization of vector, axial-vector and tensor fermion bilinears on the lattice

We compute the two-loop renormalization functions, in the RI{sup '} scheme, of local bilinear quark operators {psi}{gamma}{psi}, where {gamma} corresponds to the vector, axial-vector, and tensor Dirac operators, in the lattice formulation of QCD. We consider both the flavor nonsinglet and singlet operators. We use the clover action for fermions and the Wilson action for gluons. Our results are given as a polynomial in c{sub SW}, in terms of both the renormalized and bare coupling constant, in the renormalized Feynman gauge. Finally, we present our results in the MS scheme, for easier comparison with calculations in the continuum. The corresponding results, for fermions in an arbitrary representation, together with some special features of superficially divergent integrals, are included in the appendices.
Nearby, Thermally Emitting Neutron Stars

We describe a sample of thermally emitting neutron stars discovered in the ROSAT All‐Sky Survey. We discuss the basic observational properties of these objects and conclude that they are nearby, middle‐aged pulsars with moderate magnetic fields that we see through their cooling radiation. While these objects are potentially very useful as probes of matter at very high densities and magnetic fields, our lack of understanding of their surface emission limits their current utility. We discuss this and other outstanding problems: the spectral evolution of one sources and the relation of this population to the overall pulsar population.