Miracle-dz/UniFAR-FTUs huggingface dataset:
The 100 Brightest X-Ray Stars within 50 Parsecs of the Sun

Based on the Hipparcos and Tycho-2 astrometric catalogs and the ROSAT surveys, a sample of 100 stars most luminous in X-rays within or around a distance of 50 pc is culled. The smallest X-ray luminosity in the sample, in units of 1029 ergs s-1, is LX = 9.8; the strongest source in the solar neighborhood is II Peg, a RS CVn star, at LX = 175.8. With respect to the origin of X-ray emission, the sample is divided into partly overlapping classes of pre–main-sequence, post–T Tauri, and very young ZAMS objects (type XY), RS CVn–type binary stars (type RS), other active short-period binaries, including binary BY Dra–type objects (type XO), apparently single or long-period binary active evolved stars (type XG), contact binaries of WU UMa kind (type WU), apparently single or long-period binary variable stars of BY Dra kind (type BY), and objects of unknown nature (type X? ). Chromospherically active, short-period binaries (RS and XO) make up 40% of the brightest X-ray emitters, followed by young stars (XY) at 30% and unknown sources (X? ) at 15%. The fraction of spectroscopically single evolved X-ray emitters of spectral classes IV and III is quite large (10%). The sources identified as RS CVn–type stars (RS, 23 objects) are considerably stronger in X-ray than the XY-objects and the other active binaries (XO and WU, 20 objects). Seven objects have LX > 100, all RS except one XY, viz., BO Mic. Only five (22%) RS objects have LX < 25, while only three (10%) XY stars have LX > 25. Formally, the limit of LX = 25 could serve as a statistical criterion to differentiate RS and XY stars. However, the other short-period binaries (including eclipsing stars of Algol and β Lyr type) have a distribution of LX very similar to the XY objects. The contact binaries (WU) appear to be much weaker in X-rays than their detached counterparts of RS type, but the sample of the former is too small (three objects) to reach a firm conclusion. Sources matched with giants (either single or in binaries) are found to be significantly harder, with only 7% of hardness ratios below 0, than subgiants (66% of HR1 < 0) and dwarfs (59% of HR1 < 0). Almost all objects in the sample are binary or multiple stars; the fraction of components (FC), defined as the total number of components in all binary and multiple systems divided by the sum of the total number of components and single stars, is at least 0.90. The FC for the XY objects reaches 0.81, and for the unknown type 0.89. About 70% of RS objects have also visual or astrometric companions, which makes them hierarchical multiple systems. The RS objects (mostly old, evolved stars) and the XY stars have quite different kinematics. While the RS objects move at considerable velocities in apparently random directions with respect to the local standard of rest, the young stars have smaller and orderly velocities and tend to comprise expanding mini-associations such as the β Pic and the Tucana groups. The majority of the young X-ray active stars belong to the Pleiades stream with the mean heliocentric velocity (U, V, W) = (-9.6, -21.8, -7.7) km s-1.
Perturbing Supersymmetric Black Hole

An investigation of the perturbations of the Reissner-Nordstr¨om black hole in the N = 2 supergravity is presented. We prove in the extremal limit that the black hole responds to the perturbation of each ﬁeld in the same manner. We conjecture that we can match the modes of the graviton, gravitino and photon because of supersymmetry transformations.
Three-dimensional Kinetic Pulsar Magnetosphere Models: Connecting to Gamma-Ray Observations

We present three-dimensional (3D) global kinetic pulsar magnetosphere models, where the charged particle trajectories and the corresponding electromagnetic fields are treated self-consistently. For our study, we have developed a Cartesian 3D relativistic particle-in-cell code that incorporates radiation reaction forces. We describe our code and discuss the related technical issues, treatments, and assumptions. Injecting particles up to large distances in the magnetosphere, we apply arbitrarily low to high particle injection rates, and obtain an entire spectrum of solutions from close to the vacuum-retarded dipole to close to the force-free (FF) solution, respectively. For high particle injection rates (close to FF solutions), significant accelerating electric field components are confined only near the equatorial current sheet outside the light cylinder. A judicious interpretation of our models allows the particle emission to be calculated, and consequently, the corresponding realistic high-energy sky maps and spectra to be derived. Using model parameters that cover the entire range of spin-down powers of Fermi young and millisecond pulsars, we compare the corresponding model γ-ray light curves, cutoff energies, and total γ-ray luminosities with those observed by Fermi to discover a dependence of the particle injection rate, , on the spin-down power, , indicating an increase of with . Our models, guided by Fermi observations, provide field structures and particle distributions that are not only consistent with each other but also able to reproduce a broad range of the observed γ-ray phenomenologies of both young and millisecond pulsars.
On nonlocally interacting metrics, and a simple proposal for cosmic acceleration

We propose a simple, nonlocal modification to general relativity (GR) on large scales, which provides a model of late-time cosmic acceleration in the absence of the cosmological constant and with the same number of free parameters as in standard cosmology. The model is motivated by adding to the gravity sector an extra spin-2 field interacting nonlocally with the physical metric coupled to matter. The form of the nonlocal interaction is inspired by the simplest form of the Deser-Woodard (DW) model, α R1/□R, with one of the Ricci scalars being replaced by a constant m2, and gravity is therefore modified in the infrared by adding a simple term of the form m21/□R to the Einstein-Hilbert term. We study cosmic expansion histories, and demonstrate that the new model can provide background expansions consistent with observations if m is of the order of the Hubble expansion rate today, in contrast to the simple DW model with no viable cosmology. The model is best fit by w0∼−1.075 and wa∼0.045. We also compare the cosmology of the model to that of Maggiore and Mancarella (MM), m2R1/□2R, and demonstrate that the viable cosmic histories follow the standard-model evolution more closely compared to the MM model. We further demonstrate that the proposed model possesses the same number of physical degrees of freedom as in GR. Finally, we discuss the appearance of ghosts in the local formulation of the model, and argue that they are unphysical and harmless to the theory, keeping the physical degrees of freedom healthy.
Effect of vacuum assisted therapy in wound healing

Background: Vacuum assisted closure (VAC) is a new technique developed in the management of contaminated, acute, and chronic wounds. It refers to wound dressing system that continuously or intermittently apply sub-atmospheric pressure to the surface of a wound which accelerates debridement and promote healing. The optimum pressure for VAC is around 125 mmhg below ambient and this negative pressure helps in removing interstitial fluid, decreases localised edema and increases blood flow. This in turn decreases tissue bacterial levels and promotes wound healing.Methods: Hospital based prospective study.Results: Most common etiology for wounds is diabetes i.e., 50%, Most common organism cultured from wound is Staphylococcus aureus, and least is proteus. Surface area of wound is reduced to <40 cm2 in 76% cases and 7% cases had >60 cm2. After applying VAC dressing 91% of patients had bright red granulation tissue. Mean duration hospital stay was reduced to 10days in patients with VAC dressing.Conclusions: VAC or NPWT therapy is an excellent alternative modality of treatment of acute or chronic large non-healing wounds. It reduces the number of changes of dressing and reduces the time of hospital stay before definitive surgery for covering wound can be planned. Based on the data from the present study and other studies available, VAC appear to result in better and rapid healing and thus a better option of wound management technique.
Characterization of a potent plant growth promoting fungal strain Aspergillus fumigatus MCC 1721 with special reference to indole-3-acetic acid production

In the present study, indole-3-acetic acid (IAA) producing plant growth promoting fungus was isolated from rice field of Purba Bardhaman district, West Bengal, India. Among the isolated 6 strains, AP2 (Aspergillus fumigatus) was selected as best-performing plant growth promoting fungal strain as it was an efficient indole-3-acetic acid producer as well as exhibits different plant growth promoting ability viz, phosphate solubilization, siderophore production, ammonia and hydrogen cyanide production etc. Media and different growth conditions (pH, temperature, concentration of sodium chloride) were optimized for augmentation of the indole-3-acetic acid production. The genus of the selected isolate AP2 was identified as Aspergillus fumigatus both by 18S rDNA sequence-based homology and MALDI-TOF analyses of ribosomal protein. Plant growth promoting ability of Aspergillus fumigatus has been confirmed by measuring different morphological and biochemical growth parameters in Trigonella foenum-graecum L. So, AP2 (Aspergillus fumigatus) can be considered as novel plant growth promoting fungal strain that can be applied as bio-inoculants on agricultural field.
The Living Network of Schools Owned by Teachers and Students

This paper describes a network of teachers and students who form a living system of education at all levels and achieve high standards. The key process of the network is the process of effective learning by inquiry. Physics is distinguished among sciences as the most transparent source of understanding what it means to learn effectively by inquiry. We suggest that teachers and others who are interested in building the network start from learning about the contexts of productive learning by inquiry using specially designed and well tested materials from education of physics. We provide an outline of the process of creating the network.
Correlation-consistency cartography of the double-inflation landscape

We show explicitly some exciting features of double inflation: (i) it can often lead to strongly correlated adiabatic and entropy (isocurvature) power spectra; (ii) the two-field slow-roll consistency relations can be violated when the correlation is large at the Hubble crossing; (iii) the spectra of adiabatic and entropy perturbations can be strongly scale dependent and tilted toward either the red or blue. These effects are typically due to a light or time-dependent entropy mass and a non-negligible angular velocity in field space during inflation. They are illustrated via a multiparameter numerical search for correlations in two concrete models. The correlation is found to be particularly strong in a supersymmetric scenario due to the rapid growth of entropy perturbations in the tachyonic region separating the two inflationary stages. Our analysis suggests that realistic double-inflation models will provide a rich and fruitful arena for the application of future cosmic data sets and new approximation schemes which go beyond slow roll.
Universal ratio of magnetization moments in two-dimensional Ising models

The authors calculate the universal critical-point ratios of the square of the second and the fourth moment of the magnetization for ferromagnetic Ising models on the square and on the triangular lattices. Periodic boundary conditions are used in accordance with the four-fold and six-fold rotational symmetries of the respective lattices. These results, which are obtained by means of an analysis of finite-size data computed with a transfer-matrix technique, have an accuracy of the order of one millionth. This analysis is also applied to rectangular systems with arbitrary aspect ratios.
Black Holes-Hedgehogs and Strings as Defects of the Universal Vacua

In the present paper, assuming the Multiple Point Principle (MPP) as a new law of Nature, we considered the existence of the two degenerate vacua of the Universe: a) the first Electroweak (EW) vacuum at $v_1\approx 246$ GeV -- "true vacuum", and b) the second Planck scale "false vacuum" at $v_2 \sim 10^{18}$ GeV. In these vacua we investigated different topological defects. The main aim of this paper is an investigation of the black-hole-hedgehogs configurations as defects of the false vacuum. In the framework of the $f(R)$ gravity, described by the Gravi-Weak unification model, we considered a black-hole solution, which corresponds to a "hedgehog" -- global monopole, that has been "swallowed" by the black-hole with mass core $M_{BH}\sim 10^{18}$ GeV and radius $\delta\sim 10^{-21}$ GeV$^{-1}$. Considering the results of the hedgehog lattice theory in the framework of the $SU(2)$ Yang-Mills gauge-invariant theory with hedgehogs in the Wilson loops, we have used the critical value of temperature for the hedgehogs confinement phase ($T_c\sim 10^{18}$ GeV). This result gave us the possibility to conclude that the SM shows a new physics (with contributions of the $SU(2)$-triplet Higgs bosons) at the scale $\sim 10$ TeV. Theory predicts the stability of the EW-vacuum and the accuracy of the MPP.
Two-variable anharmonic model for spin-crossover solids : A like-spin domains interpretation

Spin-crossover (SC) complexes are one of the most fascinating examples of molecular bistability, whose solid-state properties are tightly connected to cooperative interactions within the crystal lattice. A variety of macroscopic and microscopic models have been developed to explore the cooperative nature of the SC phenomenon. We present here a two-variable microscopic Ising-like model for SC solids, accounting for the elastic origin of the cooperativity using coupled spin and translational (lattice) degrees of freedom. Within our model, the interaction between a pair of neighboring molecules in the crystal is dependent not only on their spin states but also on their separation distance, modeled by spin-dependent Lennard-Jones (LJ) potentials. This scheme leads explicitly to local variations in the interactions, associated to the local strain induced by the molecules changing their spin state. In essence, the LJ potentials provide the anharmonicity of the crystal lattice. The equilibrium (quasistatic) properties of the proposed Hamiltonian are analyzed by Monte Carlo simulations on a regular deformable square lattice. We show that the spin dependence of the LJ potentials breaks the spin-state symmetry in the free energy. The interplay between spin and lattice degrees of freedom shows itself in the temperature evolution of the fraction of high-spin molecules and the mean lattice spacing, as a function of the intersite coupling. For strong coupling, like-spin domains nucleate and develop, evidenced by a double structure in the distribution of lattice spacings; structural relaxation occurs at the domain walls. In the weakly cooperative situation, the mean lattice constant scales directly with the fraction of high-spin species; structural relaxation spans the entire system.
GD358: Three Decades of Observations for the In-depth Asteroseismology of a DBV Star

We report on the analysis of 34 years of photometric observations of the pulsating helium atmosphere white dwarf GD358. The complete data set includes archival data from 1982 to 2006, and 1195.2 hr of new observations from 2007 to 2016. From this data set, we extract 15 frequencies representing g-mode pulsation modes, adding 4 modes to the 11 modes known previously. We present evidence that these 15 modes are ℓ = 1 modes, 13 of which belong to a consecutive sequence in radial overtone k. We perform a detailed asteroseismic analysis using models that include parameterized, complex, carbon and oxygen core composition profiles to fit the periods. Recent spectroscopic analyses place GD358 near the red edge of the DBV instability strip, at 24,000 ± 500 K and a of 7.8 ± 0.08 dex. The surface gravity translates to a mass range of 0.455–0.540 . Our best-fit model has a temperature of 23,650 K and a mass of 0.5706 . That is slightly more massive than what is suggested by the most recent spectroscopy. We find a pure helium layer mass of 10−5.50, consistent with the result of previous studies and the outward diffusion of helium over time.
Einstein and Jordan frames reconciled: A frame-invariant approach to scalar-tensor cosmology

Scalar-tensor theories of gravity can be formulated in different frames, most notably, the Einstein and the Jordan one. While some debate still persists in the literature on the physical status of the different frames, a frame transformation in scalar-tensor theories amounts to a local redefinition of the metric, and then should not affect physical results. We analyze the issue in a cosmological context. In particular, we define all the relevant observables (redshift, distances, cross sections, .) in terms of frame-independent quantities. Then, we give a frame-independent formulation of the Boltzmann equation, and outline its use in relevant examples such as particle freeze-out and the evolution of the cosmic microwave background photon distribution function. Finally, we derive the gravitational equations for the frame-independent quantities at first order in perturbation theory. From a practical point of view, the present approach allows the simultaneous implementation of the good aspects of the two frames in a clear and straightforward way.
Accuracy of geostatistical prediction of yearly precipitation in Lower Saxony

Geostatistical methods allow the interpolation of spatially referenced data. They allow the prediction of values for arbitrary points in the area of interest. From these point predictions, maps are created which display areas of low or high predicted values. Apart from three dimensional and raster plots, contour line maps are frequently used. Contours are lines with constant process values. The article describes two accuracy concepts of geostatistical predictions. Local errors describe the accuracy of individual point predictions as mean squared prediction errors. They do not describe adequately the precision of contour lines extracted from an interpolated surface. A method is proposed to construct horizontal confidence intervals for arbitrary contours. This method is based on the theory of conditional simulations and is applicable whenever a suitable simulation algorithm is found. In a case study, two geostatistical models are compared regarding both accuracy concepts. Results show that higher local precision need not induce higher contour line accuracy. It is concluded that the local error concept is not sufficient to evaluate the precision of a contour line map. Copyright © 2003 John Wiley & Sons, Ltd.
On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: III. Galactic far-infrared radiation

Using the three-component spectral model describing the FIRAS average continuum spectra, the exact analytical expressions for thermodynamic and radiative functions of Galactic far-infrared radiation are obtained. The COBE FIRAS instrument data in the 0.15–2.88 THz frequency interval at the mean temperatures of T1 = 17.72 K, T2 = 14 K and T3 = 6.73 K are used for calculating the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, total emissivity, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume and pressure for the warm, intermediate-temperature and very cold components of the Galactic continuum spectra. The generalized Stefan-Boltzmann law for warm, intermediate-temperature and very cold components is constructed. The temperature dependence of each component is determined by the formula IS–B(T) = σ′T6. This result is important when we construct the cosmological models of radiative transfer that can be applied inside the Galaxy. Within the framework of the three-component spectral model, the total number of photons in our Galaxy and the total radiation power (total luminosity) emitted from a surface of the Galaxy are calculated. Their values are NGtotal = 1.3780 × 1068 and IGtotal(T) = 1.0482 × 1036 W. Other radiative and thermodynamic properties of the Galactic far-infrared radiation (photon gas) of the Galaxy are calculated. The expressions for astrophysical parameters, such as the entropy density/Boltzmann constant and number density of the Galactic far-infrared photons are obtained. We assume that the obtained analytical expressions for thermodynamic and radiative functions may be useful for describing the continuum spectra of the far-infrared radiation for other galaxies.
Effects of a uniform magnetic field on a growing or collapsing bubble in a weakly viscous conducting fluid

The effects of a uniform magnetic field on a growing or collapsing bubble are investigated. The governing equations for the volume and shape modes of oscillation are derived. To obtain the pressure correction due to the electromagnetic field, the perturbed flow by the electromagnetic force is analyzed with the aid of the domain perturbation method. The viscous effect is assumed to be confined to a thin layer adjacent to the bubble surface. It is shown that the electromagnetic field exerts a damping force on the volume mode so that both the growing and collapsing speeds of a bubble are reduced. The magnetic field also affects the shape mode by contributing to a forcing term. Due to the forcing term, the shape of a growing–collapsing bubble becomes unstable even in the case of no initial disturbance.
String Field Theory Vertices, Integrability and Boundary States

We study Neumann coeﬃcients of the various vertices in the Witten’s open string ﬁeld theory (SFT). We show that they are not independent, but satisfy an inﬁnite set of algebraic relations. These relations are identiﬁed as so-called Hirota identities. Therefore, Neumann coeﬃcients are equal to the second derivatives of tau-function of dispersionless Toda Lattice hierarchy (this tau-function is just a partition sum of normal matrix model). As a result, certain two-vertices of SFT are identiﬁed with the Neumann boundary states on an arbitrary curve. We further analyze a class of SFT surface states, which can be re-written in the closed string language in terms of boundary states. This oﬀers a new correspondence between open string states and closed string states (boundary states) in SFT. We conjecture that these special states can be considered as describing D-branes and other extended objects as ”solitons” in SFT. We consider some explicit examples, one of them is a surface states corresponding to orientifold.
A direct transfer of layer-area graphene

A facile method is reported for the direct (polymer-free) transfer of layer-area graphene from metal growth substrates to selected target substrates. The direct route, by avoiding several wet chemical steps and accompanying mechanical stresses and contamination common to all presently reported layer-area graphene transfer methods, enables fabrication of layer-area graphene devices with unprecedented quality. To demonstrate, we directly transfer layer-area graphene from Cu growth substrates to holey amorphous carbon transmission electron microscopy (TEM) grids, resulting in robust, clean, full-coverage graphene grids ideal for high resolution TEM.