Miracle-dz/UniFAR-FTUs huggingface dataset:
The Arctic Ocean Seasonal Cycles of Heat and Freshwater Fluxes: Observation-Based Inverse Estimates

This paper presents the first estimate of the seasonal cycle of ocean and sea ice heat and freshwater (FW) fluxes around the Arctic Ocean boundary. The ocean transports are estimated primarily using 138 moored instruments deployed in September 2005–August 2006 across the four main Arctic gateways: Davis, Fram, and Bering Straits, and the Barents Sea Opening (BSO). Sea ice transports are estimated from a sea ice assimilation product. Monthly velocity fields are calculated with a box inverse model that enforces mass and salt conservation. The volume transports in the four gateways in the period (annual mean ± 1 standard deviation) are −2.1 ± 0.7 Sv in Davis Strait, −1.1 ± 1.2 Sv in Fram Strait, 2.3 ± 1.2 Sv in the BSO, and 0.7 ± 0.7 Sv in Bering Strait (1 Sv ≡ 106 m3 s−1). The resulting ocean and sea ice heat and FW fluxes are 175 ± 48 TW and 204 ± 85 mSv, respectively. These boundary fluxes accurately represent the annual means of the relevant surface fluxes. The ocean heat transport variability derives from velocity variability in the Atlantic Water layer and temperature variability in the upper part of the water column. The ocean FW transport variability is dominated by Bering Strait velocity variability. The net water mass transformation in the Arctic entails a freshening and cooling of inflowing waters by 0.62 ± 0.23 in salinity and 3.74° ± 0.76°C in temperature, respectively, and a reduction in density by 0.23 ± 0.20 kg m−3. The boundary heat and FW fluxes provide a benchmark dataset for the validation of numerical models and atmospheric reanalysis products.
Improving the sensitivity of LISA

It has been shown in several recent papers that the six Doppler data streams obtained from a triangular LISA configuration can be combined by appropriately delaying the data streams for cancelling the laser frequency noise. Raw laser noise is several orders of magnitude above the other noises and thus it is essential to bring it down to the level of other noises such as shot, acceleration, etc. A rigorous and systematic formalism using the powerful techniques of computational commutative algebra was developed, which generates in principle all the data combinations cancelling the laser frequency noise. The relevant data combinations form a first module of syzygies. In this paper, we use this formalism to advantage for optimizing the sensitivity of LISA by analysing the noise and signal covariance matrices. The signal covariance matrix is calculated for binaries whose frequency changes at most adiabatically and the signal is averaged over polarizations and directions. We then present the extremal SNR curves for all the data combinations in the module. They correspond to the eigenvectors of the noise and signal covariance matrices. A LISA ‘network’ SNR is also computed by combining the outputs of the eigenvectors. We show that substantial gains in sensitivity can be obtained by employing these strategies. The maximum SNR curve can yield an improvement up to 70% over the Michelson, mainly at high frequencies, while the improvement using the network SNR ranges from 40% to over 100%. Finally, we describe a simple toy model, in which LISA rotates in a plane. In this analysis, we estimate the improvement in the LISA sensitivity, if one switches from one data combination to another as it rotates. Here the improvement in sensitivity, if one switches optimally over three cyclic data combinations of the eigenvector, is about 55% on average over the LISA bandwidth. The corresponding SNR improvement increases to 60%, if one maximizes over the module.
Electronic properties of disordered two-dimensional carbon

Two-dimensional carbon, or graphene, is a semimetal that presents unusual low-energy electronic excitations described in terms of Dirac fermions. We analyze in a self-consistent way the effects of localized (impurities or vacancies) and extended (edges or grain boundaries) defects on the electronic and transport properties of graphene. On the one hand, point defects induce a finite elastic lifetime at low energies with the enhancement of the electronic density of states close to the Fermi level. Localized disorder leads to a universal, disorder independent, electrical conductivity at low temperatures, of the order of the quantum of conductance. The static conductivity increases with temperature and shows oscillations in the presence of a magnetic field. The graphene magnetic susceptibility is temperature dependent (unlike an ordinary metal) and also increases with the amount of defects. Optical transport properties are also calculated in detail. On the other hand, extended defects induce localized states near the Fermi level. In the absence of electron-hole symmetry, these states lead to a transfer of charge between the defects and the bulk, the phenomenon we call self-doping. The role of electron-electron interactions in controlling self-doping is also analyzed. We also discuss the integer and fractional quantum Hall effect in graphene, the role played by the edge states induced by a magnetic field, and their relation to the almost field independent surface states induced at boundaries. The possibility of magnetism in graphene, in the presence of short-range electron-electron interactions and disorder is also analyzed.
Distances of Galactic Supernova Remnants Using Red Clump Stars

We carry out a project to independently measure the distances of supernova remnants (SNRs) in the first quadrant of the Galaxy. In this project, red clump (RC) stars are used as standard candles and extinction probes to build the optical extinction (AV)–distance(D) relation in each direction of extinction-known SNRs. The distances of 15 SNRs are determined. Among them, the distances of G65.8–0.5, G66.0–0.0, and G67.6+0.9 are given for the first time. We also obtain 32 upper/lower limits of distances, and the distances to G5.7–0.1, G15.1–1.6, G28.8+1.5, and G78.2+2.1 are constrained. Most of the distances measured by the RC method are consistent with previous results. The RC method provides independent access to the distances of SNRs.
How do spiral arm contrasts relate to bars, disc breaks and other fundamental galaxy properties?

We investigate how the properties of spiral arms relate to other fundamental galaxy properties, including bars and disc breaks. We use previously published measurements of those properties, and our own measurements of arm and bar contrasts for a large sample of galaxies, using 3.6 mu m images from the Spitzer Survey of Stellar Structure in Galaxies. Flocculent galaxies are clearly distinguished from other spiral arm classes, especially by their lower stellar mass and surface density. Multi-armed and grand-design galaxies are similar in most of their fundamental parameters, excluding some bar properties and the bulge-to-total ratio. Based on these results, we revisit the sequence of spiral arm classes, and discuss classical bulges as a necessary condition for standing spiralwave modes in grand-design galaxies. We find a strong correlation between bulge-to-total ratio and bar contrast, and a weaker correlation between arm and bar contrasts. Barred and unbarred galaxies exhibit similar arm contrasts, but the highest arm contrasts are found exclusively in barred galaxies. Interestingly, the bar contrast, and its increase from flocculent to grand-design galaxies, is systematically more significant than that of the arm contrast. We corroborate previous findings concerning a connection between bars and disc breaks. In particular, in grand-design galaxies, the bar contrast correlates with the normalized disc break radius. This does not hold for other spiral arm classes or the arm contrast. Our measurements of arm and bar contrast and radial contrast profiles are publicly available.
On dual formulations of gravity

In this paper we consider a possibility to construct dual formulation of gravity where the main dynamical field is the connection and not that of tetrad eμa or metric gμν. Our approach is based on the usual dualization procedure which uses first order parent Lagrangians but in (Anti) de Sitter space and not in the flat Minkowski one. At first we consider dual formulation based on the usual terad formalism with Lorentz connection ωμab as new dynamical field. It turns out that in d = 3 dimensions such dual formulation is related with the so called exotic parity-violating interactions for massless spin-2 particles. Then we construct a dual formulation of gravity where the main dynamical object is affine connection starting with the well known first order Palatini formulation but in (Anti) de Sitter background. The final result obtained by solving equations for the metric is the Lagrangian written by Eddington in his book in 1924. Also there is an interesting connection with attempts to construct gravitational analog of Born-Infeld electrodynamics.
The mystery of the 'Kite' radio source in Abell 2626: insights from new Chandra observations

We present the results of a new Chandra study of the galaxy cluster A2626. The radio emission of the cluster shows a complex system of four symmetric arcs without known correlations with the X-ray emission. The mirror symmetry of the radio arcs toward the center and the presence of two optical cores in the central galaxy suggested that they may be created by pairs of precessing radio jets powered by dual AGNs inside the cD galaxy. However, previous observations failed to observe the second jetted AGN and the spectral trend due to radiative age along the radio arcs, thus challenging this interpretation. The new Chandra observation had several scientific objectives, including the search for the second AGN that would support the jet precession model. We focus here on the detailed study of the local properties of the thermal and non-thermal emission in the proximity of the radio arcs, in order to get more insights into their origin. We performed a standard data reduction of the Chandra dataset deriving the radial profiles of temperature, density, pressure and cooling time of the intra-cluster medium. We further analyzed the 2D distribution of the gas temperature, discovering that the south-western junction of the radio arcs surrounds the cool core of the cluster. We studied the X-ray SB and spectral profiles across the junction, finding a cold front spatially coincident with the radio arcs. This may suggest a connection between the sloshing of the thermal gas and the nature of the radio filaments, raising new scenarios for their origin. A possibility is that the radio arcs trace the projection of a complex surface connecting the sites where electrons are most efficiently reaccelerated by the turbulence that is generated by the gas sloshing. In this case, diffuse emission embedded by the arcs and with extremely steep spectrum should be most visible at very low radio frequencies.
Failure of the Mann-Whitney Test: A Note on the Simulation Study of Gibbons and Chakraborti (1991)

Abstract Gibbons and Chakraborti's (1991) interpretation of recent simulation results and their recommendations to researchers are misleading in some respects. The present note emphasizes that the Mann-Whitney test is not a suitable replacement of the Student t test when variances and sample sizes are unequal, irrespective of whether the assumption of normality is satisfied or violated. When both normality and homogeneity of variance are violated together, an effective procedure, not widely known to researchers in education and psychology, is the Fligner-Policello test or, alternatively, the Welch t' test in conjunction with transformation of the original scores to ranks.
A Third Class of Gamma-Ray Bursts?

Two classes of gamma-ray bursts have been identified so far, characterized by T90 durations shorter and longer than approximately 2 s. We show here that the BATSE 3B data allow a good fit with three Gaussian distributions in log T90. The χ2 statistic indicates a 40% probability for two-Gaussian fits, whereas the three-Gaussian fit probability is 98%. Using another statistical method, it is argued that the probability that the third class is a random fluctuation is less than 0.02%.
Particle Acceleration and Fractional Transport in Turbulent Reconnection

We consider a large-scale environment of turbulent reconnection that is fragmented into a number of randomly distributed unstable current sheets (UCSs), and we statistically analyze the acceleration of particles within this environment. We address two important cases of acceleration mechanisms when particles interact with the UCS: (a) electric field acceleration and (b) acceleration by reflection at contracting islands. Electrons and ions are accelerated very efficiently, attaining an energy distribution of power-law shape with an index 1–2, depending on the acceleration mechanism. The transport coefficients in energy space are estimated from test-particle simulation data, and we show that the classical Fokker–Planck (FP) equation fails to reproduce the simulation results when the transport coefficients are inserted into it and it is solved numerically. The cause for this failure is that the particles perform Levy flights in energy space, while the distributions of the energy increments exhibit power-law tails. We then use the fractional transport equation (FTE) derived by Isliker et al., whose parameters and the order of the fractional derivatives are inferred from the simulation data, and solving the FTE numerically, we show that the FTE successfully reproduces the kinetic energy distribution of the test particles. We discuss in detail the analysis of the simulation data and the criteria that allow one to judge the appropriateness of either an FTE or a classical FP equation as a transport model.
Hofstadter-Hubbard model with opposite magnetic fields: Bardeen-Cooper-Schrieffer pairing and superfluidity in the nearly flat butterfly bands

Despite the multi-band spectrum of the widely-known Hofstadter butterfly, it turns out that the pairing correlations of the time-reversal-symmetric Hofstadter-Hubbard model are well-described by a single order parameter that is uniform in real space. By exploiting a BCS mean-field theory for the nearly-flat butterfly-bands regime of low magnetic-flux limit, here we reveal a number of unusual superfluid properties both in the ground state and at finite temperatures. Our thorough analysis includes but is not limited to the order parameter, condensate and superfluid fractions, and the critical BCS and BKT transition temperatures.
A survey of dual active galactic nuclei in simulations of galaxy mergers: frequency and properties

We investigate the simultaneous triggering of active galactic nuclei (AGN) in merging galaxies, using a large suite of high-resolution hydrodynamical simulations. We compute dual-AGN observability time-scales using bolometric, X-ray and Eddington-ratio thresholds, confirming that dual activity from supermassive black holes (BHs) is generally higher at late pericentric passages, before a merger remnant has formed, especially at high luminosities. For typical minor and major mergers, dual activity lasts ∼20–70 and ∼100–160 Myr, respectively. We also explore the effects of X-ray obscuration from gas, finding that the dual-AGN time decreases at most by a factor of ∼2, and of contamination from star formation. Using projected separations and velocity differences rather than three-dimensional quantities can decrease the dual-AGN time-scales by up to ∼4, and we apply filters that mimic current observational-resolution limitations. In agreement with observations, we find that for a sample of major and minor mergers hosting at least one AGN, the fraction harbouring dual AGN is ∼20–30 and ∼1–10 per cent, respectively. We quantify the effects of merger mass ratio (0.1 to 1), geometry (coplanar, prograde and retrograde, and inclined), disc gas fraction and BH properties, finding that the mass ratio is the most important factor, with the difference between minor and major mergers varying between factors of a few to orders of magnitude, depending on the luminosity and filter used. We also find that a shallow imaging survey will require very high angular resolution whereas a deep imaging survey will be less resolution-dependent.
Observation of the March maximum in the daemon flux from near-Earth orbits in the year 2005: new efforts and new effects

The experiments in 2005 aimed at detection of low-velocity (about 10–15 km s− 1) daemons falling on to the Earth's surface from near-Earth, almost circular heliocentric orbits have corroborated once more the existence of the March maximum in their flux by raising the confidence level to 99.99%. In addition, these experiments permitted us to identify several FEU-167-1-type photomultiplier tubes, with an inner aluminium coating a few times thicker, which appear to be capable of detecting, without any scintillator, the crossing of negatively charged daemons. As a result, the detection efficiency increases tens of times, thus raising the measured level of the March daemon flux to f ⊕ ≥ 0.5 × 10− 7 cm− 2 s− 1.
Local asymptotic normality for qubit states

We consider $n$ identically prepared qubits and study the asymptotic properties of the joint state ${\ensuremath{\rho}}^{\ensuremath{\bigotimes}n}$. We show that for all individual states, $\ensuremath{\rho}$ situated in a local neighborhood of size $1∕\sqrt{n}$ of a fixed state ${\ensuremath{\rho}}^{\mathbf{0}}$, the joint state converges to a displaced thermal equilibrium state of a quantum harmonic oscillator. The precise meaning of the convergence is that there exists physical transformations ${T}_{n}$ (trace preserving quantum channels) which map the qubits states asymptotically close to their corresponding oscillator state, uniformly over all states in the local neighborhood. A few consequences of the main result are derived. We show that the optimal joint measurement in the Bayesian setup is also optimal within the point-wise approach. Moreover, this measurement converges to the heterodyne measurement which is the optimal joint measurement of position and momentum for the quantum oscillator. A problem of local state discrimination is solved using local asymptotic normality.
Effect of a magnetic field on the long-range magnetic order in insulating Nd 2 CuO 4 and nonsuperconducting and superconducting Nd 1.85 Ce 0.15 CuO 4

We have measured the effect of a c-axis-aligned magnetic field on the long-range magnetic order of insulating Nd2CuO4, as-grown nonsuperconducting and superconducting Nd1.85Ce0. 15CuO4. On cooling from room temperature, Nd2CuO4 goes through a series of antiferromagnetic (AF) phase transitions with different noncollinear spin structures. In all phases of Nd2CuO4, we find that the applied c-axis field induces a canting of the AF order but does not alter the basic zero-field noncollinear spin structures. A similar behavior is also found in as-grown nonsuperconducting Nd1.85Ce0. 15CuO4. These results contrast dramatically with those of superconducting Nd1.85Ce0. 15CuO4, where the c-axis-aligned magnetic field induces a static, anomalously conducting, long-range ordered AF state. We confirm that the annealing process necessary to make superconducting Nd1.85Ce0. 15CuO4 also induces epitaxial, three-dimensional long-range-ordered cubic (Nd,Ce)(2)O-3 as a small impurity phase. In addition, the annealing process makes a series of quasi-two-dimensional superlattice reflections associated with lattice distortions of Nd1.85Ce0. 15CuO4 in the CuO2 plane. While the application of a magnetic field will induce a net moment in the impurity phase, we determine its magnitude and eliminate this as a possibility for the observed magnetic-field-induced effect in superconducting Nd1.85Ce0. 15CuO4. This is confirmed by measurements of the (1/2,1/2,3) peak, which is not lattice matched to the impurity phase.
Seasonality of Deaths Due to Heart Diseases among Cancer Patients

Background and Objectives: Cancer patients are at increased short- and long-term risk of cardiac toxicity and mortality. It is well-known that cardiac morbidity and mortality follows a seasonal pattern. Here we address the question of whether heart disease-related fatalities among cancer patients also follow a seasonal pattern. Materials and Methods: We performed a retrospective analysis of seasonality of deaths due to heart diseases (n = 503,243) in patients with newly diagnosed cancer reported during the period from 1975 to 2016 in the US’s largest cancer registry—the Surveillance, Epidemiology, and End Results (SEER) database. Seasonality was assessed through a classical cosinor model assuming a single annual peak. Results: We identified a significant seasonal peak in the first half of November. A peak with identical features was for all subgroups of patients defined based on demographic characteristics. This was also the case when analysis was performed on subgroups defined by the type of malignancy. Only patients with acute leukemias, pancreatic cancer and nervous system malignancies did not have a seasonal pattern in heart disease-related fatalities. Conclusion: the rate of heart disease-related fatalities after cancer diagnosis follows a seasonal pattern similar to that observed for the general population, albeit with an earlier peak in November. This suggests that close monitoring of the cardiovascular system in cancer survivors must be particularly active from late autumn and during the entire winter period.
Epstein-Barr Virus-Induced Genes and Endogenous Retroviruses in Immortalized B Cells from Patients with Multiple Sclerosis

The immune pathogenesis of multiple sclerosis (MS) is thought to be triggered by environmental factors in individuals with an unfavorable genetic predisposition. Epstein–Barr virus (EBV) infection is a major risk factor for subsequent development of MS. Human endogenous retroviruses (HERVs) can be activated by EBV, and might be a missing link between an initial EBV infection and the later onset of MS. In this study, we investigated differential gene expression patterns in EBV-immortalized lymphoblastoid B cell lines (LCL) from MS-affected individuals (MSLCL) and controls by using RNAseq and qRT-PCR. RNAseq data from LCL mapped to the human genome and a virtual virus metagenome were used to identify possible biomarkers for MS or disease-relevant risk factors, e.g., the relapse rate. We observed that lytic EBNA-1 transcripts seemed to be negatively correlated with age leading to an increased expression in LCL from younger PBMC donors. Further, HERV-K (HML-2) GAG was increased upon EBV-triggered immortalization. Besides the well-known transactivation of HERV-K18, our results suggest that another six HERV loci are up-regulated upon stimulation with EBV. We identified differentially expressed genes in MSLCL, e.g., several HERV-K loci, ERVMER61-1 and ERV3-1, as well as genes associated with relapses. In summary, EBV induces genes and HERV in LCL that might be suitable as biomarkers for MS or the relapse risk.
Solar Overshoot Region and Small-scale Dynamo with Realistic Energy Flux

We carry out high-resolution calculations of the solar overshoot region with unprecedentedly realistic parameters, especially the small energy flux compared with , where ρ and cs are density and speed of sound. Our main purpose is to investigate the behavior of the overshoot and the small-scale dynamo with parameters as close as possible to those of the Sun. Our calculations show that the bottom part of the convection zone (CZ) becomes subadiabatic, which efficiently suppresses downflows. As a result, we see a steep transition from the CZ to the radiative zone, whose width is estimated to be 0.4% of the local pressure scale height. This result is consistent with a semianalytic convection/overshoot model. We also find that the small-scale dynamo becomes efficient with a smaller energy flux. The sudden suppression of the downflows around the base of the CZ increases the efficiency of the small-scale dynamo.