Miracle-dz/UniFAR-FTUs huggingface dataset:
Method of difference potentials and its applications

I. Justification of Algorithms of the Method. - 1. Preliminaries. - 2. Differential and Difference Potentials. - 3. Reduction of Boundary-Value Problems for the Laplace Equation to Boundary Equations of Calderon-Seeley Type. - 4. Numerical Solution of Boundary-Value Problems. - II. General Constructions of Surface Potentials. - 1. Generalized Potentials and Boundary Equations with Projections for Differential Operators. - 2. General Constructions of Potentials and Boundary Equations for Difference Operators. - 3. Lazarev's Results on the Algebraic Structure of the Set of Surface Potentials of a Linear Operator. - III. A General Scheme of the Method of Difference. - 1. A General Scheme of the Method of Difference Potentials for Differential Problems. - 2. Illustrations of Constructions of the Method of Difference Potentials. - 3. General Scheine of the Method of Difference Potentials for Solving Numerically the Difference Analogs of Differential Boundary-Value Problems. - IV. Examples of MDP Algorithms for Solving. - 1. The Tricomi Problem. - 2. Constructions of the Method of Difference Potentials for the Computation of Stressed States of Elastic Compressible Materials. - 3. Problems of Internal Flows of Viscous Incompressible Fluids. - 4. An Example of the MDP Algorithm for Computing the Stationary Acoustic Wave Field outside a Solid of Revolution. - V. Artificial Boundary Conditions. - 1. An Efficient Algorithm for Constructing Artificial Boundary Conditions for a Model Problem. - 2. On the Results of the Application of the Method of Difference Potentials to the Construction of Artificial Boundary Conditions for External Flow Computations. - VI. General Constructions of Difference. - 1. Nonreflecting Difference Conditions on the Moving and Shape Varying Boundary of the Computational Domain. - 2. Spectral Approach to the Construction of Nonreflecting Boundary Conditions. - VII. Nonreflecting Artificial Boundary Conditions. - 1. Problem of Constructing NRABCs and the Corresponding Auxiliary Cauchy Problem. - 2. Algorithm for Solving the Cauchy Problem with the Help of Lacunas. - VIII. Problems of Active Shielding and Imitation. - 1. Active Shielding Control. - 2. Difference Imitation Problems. - References.
Collapse of the quantum correlation hierarchy links entropic uncertainty to entanglement creation

Quantum correlations have fundamental and technological interest, and hence many measures have been introduced to quantify them. Some hierarchical orderings of these measures have been established, for example, discord is bigger than entanglement, and we present a class of bipartite states, called premeasurement states, for which several of these hierarchies collapse to a single value. Because premeasurement states are the kind of states produced when a system interacts with a measurement device, the hierarchy collapse implies that the uncertainty of an observable is quantitatively connected to the quantum correlations (entanglement, discord, etc.) produced when that observable is measured. This fascinating connection between uncertainty and quantum correlations leads to a reinterpretation of entropic formulations of the uncertainty principle, so-called entropic uncertainty relations, including ones that allow for quantum memory. These relations can be thought of as lower bounds on the entanglement created when incompatible observables are measured. Hence, we find that entanglement creation exhibits complementarity, a concept that should encourage exploration into ``entanglement complementarity relations. ''
Hydrodynamical simulations and semi-analytic models of galaxy formation: two sides of the same coin

In this work we develop a new method to turn a state-of-the-art hydrodynamical cosmological simulation of galaxy formation (HYD) into a simple semi-analytic model (SAM). This is achieved by summarizing the efficiencies of accretion, cooling, star formation and feedback given by the HYD, as functions of the halo mass and redshift. The SAM then uses these functions to evolve galaxies within merger trees that are extracted from the same HYD. Surprisingly, by turning the HYD into a SAM, we conserve the mass of individual galaxies, with deviations at the level of 0.1 dex, on an object-by-object basis, with no significant systematics. This is true for all redshifts, and for the mass of stars and gas components, although the agreement reaches 0.2 dex for satellite galaxies at low redshift. We show that the same level of accuracy is obtained even in case the SAM uses only one phase of gas within each galaxy. Moreover, we demonstrate that the formation history of one massive galaxy provides sufficient information for the SAM to reproduce the population of galaxies within the entire cosmological box. The reasons for the small scatter between the HYD and SAM galaxies are as follows. (i) The efficiencies are matched as functions of the halo mass and redshift, meaning that the evolution within merger trees agrees on average. (ii) For a given galaxy, efficiencies fluctuate around the mean value on time-scales of 0.2–2 Gyr. (iii) The various mass components of galaxies are obtained by integrating the efficiencies over time, averaging out these fluctuations. We compare the efficiencies found here to standard SAM recipes and find that they often deviate significantly. For example, here the HYD shows smooth accretion that is less effective for low-mass haloes, and is always composed of hot or dilute gas; cooling is less effective at high redshift, and star formation changes only mildly with cosmic time. The method developed here can be applied in general to any HYD, and can thus serve as a common language for both HYDs and SAMs.
SNR 0104-72.3: A REMNANT OF A TYPE Ia SUPERNOVA IN A STAR-FORMING REGION?

We report our 110 ks Chandra observations of the supernova remnant (SNR) 0104-72.3 in the Small Magellanic Cloud (SMC). The X-ray morphology shows two prominent lobes along the northwest–southeast direction and a soft faint arc in the east. Previous low-resolution X-ray images attributed the unresolved emission from the southeastern lobe to a Be/X-ray star. Our high-resolution Chandra data clearly show that this emission is diffuse, shock-heated plasma, with negligible X-ray emission from the Be star. The eastern arc is positionally coincident with a filament seen in optical and infrared observations. Its X-ray spectrum is well fit by plasma of normal SMC abundances, suggesting that it is from shocked ambient gas. The X-ray spectra of the lobes show overabundant Fe, which is interpreted as emission from the reverse-shocked Fe-rich ejecta. The overall spectral characteristics of the lobes and the arc are similar to those of Type Ia SNRs, and we propose that SNR 0104-72.3 is the first case for a robust candidate Type Ia SNR in the SMC. On the other hand, the remnant appears to be interacting with dense clouds toward the east and to be associated with a nearby star-forming region. These features are unusual for a standard Type Ia SNR. Our results suggest an intriguing possibility that the progenitor of SNR 0104-72.3 might have been a white dwarf of a relatively young population.
LUMINOSITY FUNCTIONS OF SPITZER-IDENTIFIED PROTOSTARS IN NINE NEARBY MOLECULAR CLOUDS

We identify protostars in Spitzer surveys of nine star-forming (SF) molecular clouds within 1 kpc: Serpens, Perseus, Ophiuchus, Chamaeleon, Lupus, Taurus, Orion, Cep OB3, and Mon R2, which combined host over 700 protostar candidates. These clouds encompass a variety of SF environments, including both low-mass and high-mass SF regions, as well as dense clusters and regions of sparsely distributed star formation. Our diverse cloud sample allows us to compare protostar luminosity functions in these varied environments. We combine near- and mid-infrared photometry from the Two Micron All Sky Survey and Spitzer to create 1–24 μm spectral energy distributions (SEDs). Using protostars from the c2d survey with well-determined bolometric luminosities, we derive a relationship between bolometric luminosity, mid-IR luminosity (integrated from 1–24 μm), and SED slope. Estimations of the bolometric luminosities for protostar candidates are combined to create luminosity functions for each cloud. Contamination due to edge-on disks, reddened Class II sources, and galaxies is estimated and removed from the luminosity functions. We find that luminosity functions for high-mass SF clouds (Orion, Mon R2, and Cep OB3) peak near 1 L☉ and show a tail extending toward luminosities above 100 L☉. The luminosity functions of the low-mass SF clouds (Serpens, Perseus, Ophiuchus, Taurus, Lupus, and Chamaeleon) do not exhibit a common peak, however the combined luminosity function of these regions peaks below 1 L☉. Finally, we examine the luminosity functions as a function of the local surface density of young stellar objects. In the Orion molecular clouds, we find a significant difference between the luminosity functions of protostars in regions of high and low stellar density, the former of which is biased toward more luminous sources. This may be the result of primordial mass segregation, although this interpretation is not unique. We compare our luminosity functions to those predicted by models and find that our observed luminosity functions are best matched by models that invoke competitive accretion, although we do not find strong agreement between the high-mass SF clouds and any of the models.
Spacetime near isolated and dynamical trapping horizons

We study the near-horizon spacetime for isolated and dynamical trapping horizons (equivalently marginally outer trapped tubes). The metric is expanded relative to an ingoing Gaussian null coordinate and the terms of that expansion are explicitly calculated to second order. For the spacelike case, knowledge of the intrinsic and extrinsic geometry of the (dynamical) horizon is sufficient to determine the near-horizon spacetime, while for the null case (an isolated horizon) more information is needed. In both cases spacetime is allowed to be of arbitrary dimension and the formalism accommodates both general relativity as well as more general field equations. The formalism is demonstrated for two applications. First, spacetime is considered near an isolated horizon and the construction is both checked against the Kerr-Newman solution and compared to the well-known near-horizon limit for stationary extremal black hole spacetimes. Second, spacetime is examined in the vicinity of a slowly evolving horizon and it is demonstrated that there is always an event horizon candidate in this region. The geometry and other properties of this null surface match those of the slowly evolving horizon to leading order and in this approximation the candidate evolves in a locally determined way. This generalizes known results for Vaidya as well as certain spacetimes known from studies of the fluid-gravity correspondence.
Effect of crystallographic anisotropy on the resistance switching phenomenon in perovskites

Resistance switching effects in metal/perovskite contacts based on epitaxial c-axis oriented YBa2Cu3O6+c (YBCO) thin films with different crystallographic orientation have been studied. Three types of Ag/YBCO junctions with the contact restricted to (i) c-axis direction, (ii) ab-plane direction, and (iii) both were designed and fabricated, and their current-voltage characteristics have been measured. The type (i) junctions exhibited conventional bipolar resistance switching behavior, whereas in other two types the low-resistance state was unsteady and their resistance quickly relaxed to the initial high-resistance state. Physical mechanism based on the oxygen diffusion scenario, explaining such behavior, is discussed.
Microscopic mechanism for the (1)/(8) magnetization plateau in SrCu 2 (BO 3 ) 2

The frustrated quantum magnet SrCu_2(BO_3)_2 shows a remarkably rich phase diagram in an external magnetic field including a sequence of magnetization plateaux. The by far experimentally most studied and most prominent magnetization plateau is the 1/8 plateau. Theoretically, one expects that this material is well described by the Shastry-Sutherland model. But recent microscopic calculations indicate that the 1/8 plateau is energetically not favored. Here we report on a very simple microscopic mechanism which naturally leads to a 1/8 plateau for realistic values of the magnetic exchange constants. We show that the 1/8 plateau with a diamond unit cell benefits most compared to other plateau structures from quantum fluctuations which to a large part are induced by Dzyaloshinskii-Moriya interactions. Physically, such couplings result in kinetic terms in an effective hardcore boson description leading to a renormalization of the energy of the different plateaux structures which we treat in this work on the mean-field level. The stability of the resulting plateaux are discussed. Furthermore, our results indicate a series of stripe structures above 1/8 and a stable magnetization plateau at 1/6. Most qualitative aspects of our microscopic theory agree well with a recently formulated phenomenological theory for the experimental data of SrCu_2(BO_3)_2. Interestingly, our calculations point to a rather large ratio of the magnetic couplings in the Shastry-Sutherland model such that non-perturbative effects become essential for the understanding of the frustrated quantum magnet SrCu_2(BO_3)_2.
Rosen's gradient projection method for solving a constrained convex programming problem

When the classical Rosen’s method is applied to solving the dual of a convex programming problem, calculating the projection gradient direction at each iteration involves solving a minimization problem of Lagrangian function. By employing any parallel algorithms, an approximate solution can be obtained, which can approach any accuracy of the optimal solution. It is illustrated that, if the sequence of accuracies are properly chosen, the value of the dual variable at the -th iterate, generated by the modified Rosen’s method, converges to the optimal solution to the dual problem and the generated sequence also converges to the optimal solution to the original convex programming problem.
Targeting local orogenic gold mineralisation zones using data-driven evidential belief functions: the Godarsorkh area, Central Iran

ABSTRACT Using GIS-based multi-criteria decision-making techniques, i.e. mineral prospectivity mapping (MPM), specific spatial problems can be solved by combining information from different sources. Orogenic gold mineralisation shows weak exploration signals on the surface that can challenge exploration geologists. This study investigates the ability of a MPM method called evidential belief functions (EBFs) to identify a local orogenic gold mineralisation in the Godaesorkh gold deposit, north of Sanandaj-Sirjan Zone (Central Iran). Several evidential layers such as geological, structural, geophysical, remote sensing, and geochemical layers were generated by applying various processing methods. These layers are integrated to attain a MPM by applying the EBFs based on Dempster-Shafer’s rules. Precise selection of evidential layers and higher number of known mineral occurrences may lead to a higher degree of belief in the mineral prospectivity map. Accordingly, high probability values were correlated with the gold mineralisation in the study area, and three separate areas were identified as promising with N40E and N15W trends. It is concluded that the orogenic gold mineralisation occurred in shear zones, which is mainly controlled by tectonic structures. Consequently, analysing these structures can be considered as a key feature for identifying potential orogenic gold mineralisation zones in the study area.
Euclid Definition Study Report

Euclid is a space-based survey mission from the European Space Agency designed to understand the origin of the Universe's accelerating expansion. It will use cosmological probes to investigate the nature of dark energy, dark matter and gravity by tracking their observational signatures on the geometry of the universe and on the cosmic history of structure formation. The mission is optimised for two independent primary cosmological probes: Weak gravitational Lensing (WL) and Baryonic Acoustic Oscillations (BAO). The Euclid payload consists of a 1.2 m Korsch telescope designed to provide a large field of view. It carries two instruments with a common field-of-view of ~0.54 deg2: the visual imager (VIS) and the near infrared instrument (NISP) which contains a slitless spectrometer and a three bands photometer. The Euclid wide survey will cover 15,000 deg2 of the extragalactic sky and is complemented by two 20 deg2 deep fields. For WL, Euclid measures the shapes of 30-40 resolved galaxies per arcmin2 in one broad visible R+I+Z band (550-920 nm). The photometric redshifts for these galaxies reach a precision of dz/(1+z) < 0.05. They are derived from three additional Euclid NIR bands (Y, J, H in the range 0.92-2.0 micron), complemented by ground based photometry in visible bands derived from public data or through engaged collaborations. The BAO are determined from a spectroscopic survey with a redshift accuracy dz/(1+z) =0.001. The slitless spectrometer, with spectral resolution ~250, predominantly detects Ha emission line galaxies. Euclid is a Medium Class mission of the ESA Cosmic Vision 2015-2025 programme, with a foreseen launch date in 2019. This report (also known as the Euclid Red Book) describes the outcome of the Phase A study.
High Order Local Divergence Preservation for MHD Finite Volume Methods

Violation of the divergence constraint on the magnetic flux density in magnetohydrodynamical (MHD) simulations leads to stability problems and it is therefore of great importance to numerically respect this intrinsic constraint. Especially in shock computations with discontinous fields, divergence errors tend to accumulate and introduce strong oscillations. In [1] it has been shown that an intrinsic differential constraint can be incorporated into the flux of a finite volume method by respecting special shape functions as flux distribution. This leads to a seamless and local divergence preservation. The second order scheme for MHD has been investigated in [2].
Integrative Functional Genomic Analysis in Multiplex Autism Families from Kazakhstan

The study of extended pedigrees containing autism spectrum disorder- (ASD-) related broader autism phenotypes (BAP) offers a promising approach to the search for ASD candidate variants. Here, a total of 650,000 genetic markers were tested in four Kazakhstani multiplex families with ASD and BAP to obtain data on de novo mutations (DNMs), common, and rare inherited variants that may contribute to the genetic risk for developing autistic traits. The variants were analyzed in the context of gene networks and pathways. Several previously well-described enriched pathways were identified, including ion channel activity, regulation of synaptic function, and membrane depolarization. Perhaps these pathways are crucial not only for the development of ASD but also for ВАР. The results also point to several additional biological pathways (circadian entrainment, NCAM and BTN family interactions, and interaction between L1 and Ankyrins) and hub genes (CFTR, NOD2, PPP2R2B, and TTR). The obtained results suggest that further exploration of PPI networks combining ASD and BAP risk genes can be used to identify novel or overlooked ASD molecular mechanisms.
Clustering of variables in regression analysis: a comparative study between different algorithms

We have recently suggested using clustering of variables (CLoVA) based on unsupervised pattern recognition for partitioning variables into informative and redundant ones. Because data clustering plays a central role in CLoVA, in the present study, we compared the efficiency of different clustering methods including the Kohonen self‐organizing map (SOM), principal component analysis, fuzzy c‐means clustering, K‐means clustering, and hierarchical cluster analysis for clustering spectroscopic data and molecular descriptors to build multivariate calibration and quantitative structure–activity (QSAR) models. To investigate which clustering methods are more efficient for CLoVA, four data sets (three spectroscopic and one QSAR) were analyzed. Most of the CLoVA‐based models obtained by SOM resulted in the least root mean square errors of cross‐validation and prediction, suggesting a higher efficiency of SOM for clustering variables. In all cases, the results obtained by the CLoVA‐based method were compared with those obtained by conventional principal component regression as well as genetic algorithm and successive projection algorithm partial least square regression. Interestingly, models produced by the CLoVA‐based method were more predictive with respect to that of the other methods, as indicated by the lowest root mean square error of prediction. Copyright © 2013 John Wiley & Sons, Ltd.
Implementing molecular hydrogen in hydrodynamic simulations of galaxy formation

Motivated by the observed connection between molecular hydrogen (H2) and star formation, we present a method for tracking the non-equilibrium abundance and cooling processes of H2 and H2-based star formation in smoothed particle hydrodynamic simulations. The local abundances of H2 are calculated by integrating over the hydrogen chemical network. This calculation includes the gas phase and dust grain formation of H2, shielding of H2 and photodissociation of H2 by Lyman–Werner radiation from nearby stellar populations. Because this model does not assume equilibrium abundances, it is particularly well suited for simulations that model low-metallicity environments, such as dwarf galaxies and the early Universe. We further introduce an explicit link between star formation and local H2 abundance. This link limits star formation to ‘star-forming regions’, represented by areas with abundant H2. We use simulations of isolated disc galaxies to verify that the transition from atomic to molecular hydrogen occurs at realistic densities and surface densities. Using these same isolated galaxies, we establish that gas particles of 104 M⊙ or less are necessary to follow the molecular gas in this implementation. With this implementation, we determine the effect of H2 on star formation in a cosmological simulation of a dwarf galaxy. This simulation is the first cosmological simulation with non-equilibrium H2 abundances to be integrated to a redshift of zero or to include efficient supernova feedback. We analyse the amount and distribution of star formation in the galaxy using simulated observations of the H i gas and in various optical bands. From these simulated observations, we find that our simulations are consistent with the observed Tully–Fisher, global Kennicutt–Schmidt and resolved Kennicutt–Schmidt relations. We find that the inclusion of shielding of both the atomic and molecular hydrogen and, to a lesser extent, the additional cooling from H2 at temperatures between 200 and 5000 K increases the amount of cold gas in the galaxies. The changes to the interstellar medium (ISM) result in an increased amount of cold, dense gas in the disc of the galaxy and the formation of a clumpier ISM. The explicit link between star formation and H2 and the clumpier ISM results in a bluer galaxy with a greater spatial distribution of star formation at a redshift of zero.