Miracle-dz/UniFAR-FTUs huggingface dataset:
Effect of spin fluctuations on the magnetic equation of state of ferromagnetic or nearly ferromagnetic metals

The authors present a quantitative model for the magnetic equation of state of nearly or weakly ferromagnetic metals at low temperatures which includes corrections to conventional Stoner theory arising from enhanced fluctuations in the local magnetisation. The model takes account of both longitudinal and transverse fluctuations in terms of four physically transparent parameters which may be determined independently from the equation of state in the T=0 limit and from inelastic neutron scattering, or calculated directly from a semi-empirical band structure model near the Fermi level fitted for example to experimental Fermi surface areas. For parameters of the same order of magnitude as those recently determined in the weakly spin-polarised metal Ni3Al, the model yields approximately a quadratic temperature dependence of the spontaneous magnetisation over a wide range well below the Curie temperature (Tc), a nearly linear inverse susceptibility well above Tc, and nearly linear magnetic isotherms (Arrott plots) at high magnetic fields. These results are qualitatively consistent with the behaviour observed in many magnetic metals near the ferromagnetic instability at low temperatures. For Ni3Al the model yields good quantitative agreement with experiment for the magnitude of the Curie temperature Tc, for the ratio peff/p0 of the high- to low-temperature effective magnetic moments, and for the coefficient of the quadratic (T2) variation of the magnetisation with temperature well below Tc, without the use of any free adjustable parameters. Finally the authors show that the model also provides a good quantitative description of the paramagnetic susceptibility and transition temperature of the more complex magnetic system MnSi, the only other unsaturated magnetic metal for which all of the microscopic parameters are well known.
Positron scattering from molecular hydrogen

We present results for total and partial cross sections for positron scattering from H2. The total scattering and positronium formation cross sections are reported between 0.5 and 200 eV. Total quasielastic and inelastic scattering cross sections are reported for energies between the positronium formation threshold and 50 eV, with quasielastic differential scattering cross sections reported at 1, 3, 5, 7, and 10 eV. Our results are compared with previous work, both experimental and theoretical, with particular attention paid to the region below the positronium formation threshold, where there are apparent discrepancies in previous work. A discussion of possible reasons for discrepancies between this and previous work is presented, including a focus on known systematic effects in the experimental results.
Ertel's vorticity theorem and new flux surfaces in multi-fluid plasmas

Dedicated to Professor Harold Weitzner on the occasion of his retirement“Say to wisdom ‘you are my sister,’ and to insight ‘you are my relative. ’”—Proverbs 7:4Based on an extension to plasmas of Ertel's classical vorticity theorem in fluid dynamics, it is shown that for each species in a multi-fluid plasma there can be constructed a set of nested surfaces that have this species' fluid particles confined within them. Variational formulations for the plasma evolution and its equilibrium states are developed, based on the new surfaces and all of the dynamical conservation laws associated with them. It is shown that in the general equilibrium case, the energy principle lacks a minimum and cannot be used as a stability criterion. A limit of the variational integral yields the two-fluid Hall-magnetohydrodynamic (MHD) model. A further special limit yields MHD equilibria and can be used to approximate the equilibrium state of a Hall-MHD plasma in a perturbative way.
Theory-based modeling of particle transport in ASDEX Upgrade H-mode plasmas, density peaking, anomalous pinch and collisionality

The theoretical prediction of density profiles in tokamak plasmas plays a major role for the prediction of the plasma performance in a fusion reactor. The density peaking measured in plasmas in high confinement mode of the ASDEX Upgrade tokamak [O. Gruber, H. -S. Bosch, S. Gunter et al., Nucl. Fusion 39, 1321 (1999)] is shown to decrease with increasing collisionality. This experimental behavior is explained with a theoretical fluid transport model for ion temperature gradient and trapped electron modes, GLF23, which includes a valid description of the effects of collisions on these instabilities. Collisionless reactive models, like the Weiland model, are in disagreement with the experimental observations. The difference between the predictions of the two models must be ascribed to collisionality. This has been ascertained by a detailed comparison of the physics content of the two models and by the implementation of modified, collisionless versions of the GLF23 model, which yield results analogous to those.
Preheating of the nonminimally coupled inflaton field

We investigate preheating of an inflaton field $\phi$ coupled nonminimally to a spacetime curvature. In the case of a self-coupling inflaton potential $V(\phi)=\lambda \phi^4/4$, the dynamics of preheating changes by the effect of the negative $\xi$. We find that the nonminimal coupling works in two ways. First, since the initial value of inflaton field for reheating becomes smaller with the increase of $|\xi|$, the evolution of the inflaton quanta is delayed for fixed $\lambda$. Second, the oscillation of the inflaton field is modified and the nonadiabatic change around $\phi=0$ occurs significantly. That makes the resonant band of the fluctuation field wider. Especially for strong coupling regimes $|\xi| \gg 1$, the growth of the inflaton flutuation is dominated by the resonance due to the nonminimal coupling, which leads to the significant enhancement of low momentum modes. Although the final variance of the inflaton fluctuation does notchange significantly compared with the minimally coupled case, we have found that the energy transfer from the homogeneous inflaton to created particles efficiently occurs for $\xi<-60$.
Comparison of Risk of Osteoporotic Fracture in Denosumab vs Alendronate Treatment Within 3 Years of Initiation

Key Points Question What is the real-world risk of fracture for patients treated with denosumab compared with those treated with alendronate? Findings In this Danish cohort study including 4624 individuals treated with denosumab and 87 731 individuals treated with alendronate, 3-year cumulative incidence of hip fracture was 3.7% and 3.1% among the denosumab and alendronate cohorts, respectively. The 3-year cumulative incidence of any fracture was 9.0% for both cohorts. Meaning In routine clinical practice, initiation of denosumab and alendronate treatments were associated with similar risks of hip and any fracture over a 3-year period.
Quasi‐thermal noise in a drifting plasma: Theory and application to solar wind diagnostic on Ulysses

The present paper provides the basic principles and analytic expressions of the quasi-thermal noise spectroscopy extended to measure the plasma bulk speed, as a tool for in situ space plasma diagnostics. This method is based on the analysis of the electrostatic field spectrum produced by the quasi-thermal fluctuations of the electrons and by the Doppler- shifted thermal fluctuations of the ions; it requires a sensitive radio receiver connected to an electric wire dipole antenna. Neglecting the plasma bulk speed, the technique has been routinely used in the low-speed solar wind, and it gives accurate measurements of the electron density and core temperature, in addition to estimates of parameters of the hot electron component. The present generalization of the method takes into account the plasma speed and thereby improves the thermal electron temperature diagnostic. The technique, which is relatively immune to spacecraft potential and photoelectron perturbations, is complementary to standard electrostatic analysers. Application to the radio receiver data from the Ulysses spacecraft yields an accurate plasma diagnostic. Comparisons of these results with those deduced from the particle analyser experiment on board Ulysses are presented and discussed.
High-pressure form of pyrite-type germanium dioxide

Structural phase transitions of germanium dioxide $({\mathrm{GeO}}_{2})$ have been investigated at pressures up to 120 GPa, which was heated to a temperature above 2000 K, using a laser-heated diamond anvil cell technique. A phase transition between ${\mathrm{CaCl}}_{2}$-type and $\ensuremath{\alpha}\ensuremath{-}{\mathrm{PbO}}_{2}$-type phases was observed at about 50 GPa. At pressures higher than 90 GPa, we also observed the occurrence of a new high-pressure phase of pyrite-type (modified-fluorite type) structure $(Pa3\ifmmode\bar\else\textasciimacron\fi{})$ that is denser than other known ${\mathrm{GeO}}_{2}$ phases. Our results were consistent with the high-pressure transition sequence of tin dioxide $({\mathrm{SnO}}_{2})$ as analog of ${\mathrm{GeO}}_{2}. $ The new structure of the ${\mathrm{GeO}}_{2}$ high-pressure phase may be that of high-pressure silica $({\mathrm{SiO}}_{2})$ phase predicted by the theoretical investigations.
Network Flow and Systems of Representatives

The theory developed for the study of flows in networks (2; 3; 4; 5; 6; 7) sometimes provides a useful tool for dealing with certain kinds of combinatorial problems, as has been previously indicated in (3; 4; 6; 7). In particular, Hall-type theorems for the existence of systems of distinct representatives which contain a prescribed set of marginal elements (10; 11), or, more generally, whose intersection with each member of a given partition of the fundamental set has a cardinality between prescribed lower and upper bounds (9), can be obtained in this way (7).
Modulation of Venus ion densities associated with solar variations

The dayside ion concentrations in the Venus ionosphere obtained by the Pioneer Venus orbiter ion mass spectrometer exhibit a modulation corresponding to the 27-day solar variation. Comparisons were made of the amplitudes of modulation of CO2+, C+, and O2+, with the amplitudes of the 27-day variation in the 10.7 cm solar radio flux and the simultaneously measured EUV fluxes at He II (304A) and Lyman β (1026A), together with a theoretical analysis of the effects of solar variability on the ionosphere and neutral atmosphere of Venus. This analysis leads us to the conclusion that the observed modulation of dayside ion densities is primarily due to the variability in the ionizing EUV radiations and, to a much lesser extent, the result of the variability with solar activity of the neutral atmosphere via the variability in exospheric temperature. In this connection, we also show, theoretically, why the percentage variation of exospheric temperature on Venus (as observed in the ONMS data) for a given variation in F10.7, is only half of the exospheric temperature variation for Earth.
Precipitation from Space: Advancing Earth System Science

Advances to space-based observing systems and data processing techniques have made precipitation datasets quickly and easily available via various data portals and widely used in Earth sciences. The increasingly lengthy time span of space-based precipitation data records has enabled cross-discipline investigations and applications that would otherwise not be possible, revealing discoveries related to hydrological and land processes, climate, atmospheric composition, and ocean freshwater budget and proving a vital element in addressing societal issues. The purpose of this article is to demonstrate how the availability and continuity of precipitation data records from recent and upcoming space missions is transforming the ways that scientific and societal issues are addressed, in ways that would not be otherwise possible.
Symbols and the Bifurcation Between Procedural and Conceptual Thinking

Symbols occupy a pivotal position between processes to be carried out and concepts to be thought about. They allow us both to do mathematical problems and to think about mathematical relationships. In this article we consider the discontinuities that occur in the learning path taken by different students, leading to a divergence between conceptual and procedural thinking. Evidence will be given from several different contexts in the development of symbols through arithmetic, algebra, and calculus, then on to the formalism of axiomatic mathematics. This evidence is taken from a number of research studies recently conducted for doctoral dissertations at the University of Warwick by students from the United States, Malaysia, Cyprus, and Brazil, with data collected in the United States, Malaysia, and the United Kingdom. All the studies form part of a broad investigation into why some students succeed, while others fail. RésuméLes symboles jouent un rôle central entre les processus à accomplir et les concepts auxquels on doit penser. Ils nous permettent à la fois de résoudre des problèmes mathématiques et de réfléchir aux relations mathématiques. Dans cet article, nous examinons les discontinuités qui apparaissent le long du chemin d’apprentissage emprunté par différents élèves et qui entraînent une divergence entre la pensée conceptuelle et la pensée procédurale. Nous fournirons des exemples tirés de plusieurs contextes différents illustrant l’acquisition des symboles par l’intermédiaire de l’arithmétique, de l’algèbre et du calcul différentiel et intégral, pour ensuite passer au formalisme des mathématiques axiomatiques. Ces exemples proviennent d’un certain nombre d’études menées récemment à l’Université de Warwick par des doctorants américains, malaisiens, chypriotes et brésiliens, et qui portent sur des données recueillies aux États‐Unis, en Malaisie et au Royaume‐Uni. Toutes ces études s’inscrivent dans le cadre d’une vaste recherche visant à déterminer les raisons pour lesquelles certains élèves réussissent alors que d’autres échouent.
Boundary Structures and Changes in Long-lived Coronal Holes

We report a first systematic morphological study of the boundaries of coronal holes (CHs) as viewed in soft X-ray images from the Yohkoh Soft X-Ray Telescope. The special emphasis is on long-lived (several rotations) CHs that extend from the solar polar regions to midlatitudes. As shown earlier, such equatorward extensions tend to show rigid, rather than differential, rotation. Magnetic reconnection must occur at the "closing" boundary, in such a case, to maintain the CH integrity. We find three kinds of CH boundaries in the soft X-ray observations. The majority are generally ragged and not sharply defined; we also find smooth boundaries to occur near a matching-polarity active region (AR), and loopy boundaries to occur near an opposite-polarity AR. In this latter case the loops clearly do not extend far enough to reach another CH but instead end in normal corona. The CH boundaries evolve slowly, and neither large-scale transient X-ray events nor coronal bright points appeared significant factors in long-term CH boundary development. No direct evidence for magnetic reconnection is seen. We compare these results with those expected from current models, derived largely from considerations of heliospheric conditions rather than the detailed appearance of CHs in the low corona.
Modeling Acceleration Effects on Ram Accelerator Thrust at High Pressure

A = tube section a = acceleration cp = isobaric heat capacity F = thrust h = specific enthalpy I = nondimensional thrust, F/(p A) L = length M = Mach number m = mass P = pressure ratio p = pressure Q = nondimensional heat release, q/cpT R = gas constant T = temperature u = velocity v = specific volume α = intermediate calculation parameter, LCVap = adiabatic specific heat capacity ratio γ = specific heat capacity ratio q = heat release η = calorific imperfection, h/cpT σ = compressibility factor
High-mobility low-temperature ZnO transistors with low-voltage operation

Low voltage high mobility n-type thin film transistors (TFTs) based on sol-gel processed zinc oxide (ZnO) were fabricated using a high capacitance ion gel gate dielectric. The ion gel gated solution-processed ZnO TFTs were found to exhibit excellent electrical properties. TFT carrier mobilities were 13 cm2/V s, ON/OFF current ratios were 105, regardless of the sintering temperature used for the preparation of the ZnO thin films. Ion gel gated ZnO TFTs are successfully demonstrated on plastic substrates for the large area flexible electronics.
Ultraviolet and optical spectrophotometry of the Seyfert 1.8 galaxy Markarian 609

Ultraviolet and optical observations of the Seyfert 1.8 galaxy Mrk 609 were collected simultaneously. The observations reveal strong line and continuum emission in the UV, an increase in the flux of H-beta and He I 5876, and a decrease in the H-alpha/H-beta value since the measurements by Osterbrock (1978, 1981), as well as an extended population of early-type stars, which is considered to be the source powering the larger part of the far-IR emission. Special attention is given to the origin of steep broad-line Balmer decrement measured by Osterbrock, since the strong UV continuum and the emission lines of Mrk 609 observed rule out reddening as the cause of the Balmer decrement. It is suggested that smaller-than-normal optical depths are likely to be the cause of the decrement.
How Many Observations Fall in a Neighborhood of an Order Statistic?

Asymptotic behavior of the number of independent identically distributed observations in a left or right neighborhood of k n th order statistic from the sample of size n, for k n /n → α ∈ [0, 1], is studied. It appears that the limiting laws are of the Poisson type.
Exponentially improved asymptotic expansions for resonances of an elliptic cylinder

Scattering by an elliptic cylinder is considered. Asymptotic expansions for Regge poles and resonances are derived from the uniform asymptotic expansions of Mathieu functions and modified Mathieu functions constructed by applying the Langer-Olver method. In addition, asymptotic expansions for resonances are exponentially improved by emphasizing the role of the symmetries of the scatterer. The splitting up of resonances is then explained in terms of the symmetry breaking O(2)⟶𝒞2v.
On randomly weighted one-sided ergodic Hilbert transforms

In this paper we obtain (almost) optimal results concerning randomly weighted one-sided ergodic Hilbert transforms. Given an iid sequence of centered random variables (Xn) in L log L, we show that there exists a universal set $\Omega'$ of probability 1 such that for any $\omega\in \Omega'$ the realization $(X_n(\omega))$ is good for the almost everywhere convergence of the weighted one-sided ergodic Hilbert transform associated with any dynamical system and any $g\in L\log L$. The method applies to powers along subsequences with ‘small’ growth and when considering Dunford–Schwartz operators instead of pointwise transformation. If the (Xn) are symmetric, but only in L log log L, we obtain a slightly weaker result.
Experimental Philosophy of Consciousness

Experimental philosophy of consciousness seeks to investigate and explain our thinking about phenomenally conscious states. Based on empirical studies, researchers have argued (a) that there is no folk concept of consciousness, (b) that we do not think Microsoft feels regret, (c) that unfelt pains are widely accepted, and (d) that people do not believe that duplicated hamsters have phenomenally conscious states. In this paper, I review these and other fascinating claims about people’s understanding of phenomenal consciousness. In doing so, I also show why experimental philosophy of consciousness is hard, although perhaps not quite as hard as studying phenomenal consciousness itself.
The Giant Branches of ω Centauri: Multiwavelength Observations of Evolved Stars

We have obtained photometric observations in a 182 arcmin2 area, 25′ to the north of the center of the globular cluster ω Centauri. The Strömgren vby and broadband BI filters were used to obtain measurements for some 2500 stars. Preliminary examinations of parts of the data have been presented previously (Hughes &Wallerstein, published in 2000; Hughes, Wallerstein, &van Leeuwen, published in 2002). Here we present the complete data set, study the giant branches, and use the B-I color index as a tool for assessing the ages of the populations within ω Cen. Our results confirm previous results for the main-sequence turnoff stars: there appears to be an age spread of about 3–5 Gyr among the stars of ω Cen. We use the proper-motion study by van Leeuwen et al. (published in 2000) to confirm cluster membership above B ∼ 16.5 and calibrate our photometry to that of Hilker and Hilker &Richtler (both published in 2000) in order to use the improved methods described by these authors for deriving metallicity estimates from the Strömgren photometry. We use data on 25 ROA stars in our field and 40 stars from Hilker to look at the enrichment history of ω Cen. We support previous findings that there is another red giant branch, redder (Lee et al., published in 1999, and Pancino et al., published in 2000), and younger than the main giant branch but containing few stars. Even though this so-called RGB-a population appears to be younger than the bulk of the stellar population, it does not seem to be younger than the most metal-rich tail of the bulk population. This last property suggests that the RGB-a may not have been the last burst of star formation in ω Cen and could support the idea, presented by Ferraro et al. and Pancino et al. (both in 2002), that it represents an accreted stellar system.
A Diagnostic Study of Three Heavy Precipitation Episodes in the Western Mediterranean Region

Abstract A diagnostic evaluation of three project ANOMALIA case studies involving heavy precipitation in the western Mediterranean region has been carried out. The evaluation shows the unique characteristics of each event, as well as some limited similarities. Heavy precipitation events in the western Mediterranean region typically occur downstream of a significant cyclone aloft (often, but not always, exhibiting “cutoff” cyclone characteristics), but important structural and evolutionary differences are found among these cases. At low levels, a long fetch of flow over the Mediterranean Sea frequently interacts with terrain features to produce persistent heavy precipitation. Although most heavy precipitation events occur during the fall season, they can develop at other times. In the first case, the synoptic-scale environment produced low static stability and substantial storm-relative environmental helicity, thereby supporting both heavy rain in the vicinity of Valencia on mainland Spain and on Ibiza in .
Entanglement complexity of graphs in Z3

Abstract In this paper we are concerned with questions about the knottedness of a closed curve of given length embedded in Z3. What is the probability that such a randomly chosen embedding is knotted? What is the probability that the embedding contains a particular knot? What is the expected complexity of the knot? To what extent can these questions also be answered for a graph of a given homeomorphism type? We use a pattern theorem due to Kesten 12 to prove that almost all embeddings in Z3 of a sufficiently long closed curve contain any given knot. We introduce the idea of a good measure of knot complexity. This is a function F which maps the set of equivalence classes of embeddings into 0, ). The F measure of the unknot is zero, and, generally speaking, the more complex the prime knot decomposition of a given knot type, the greater its F measure. We prove that the average value of F diverges to infinity as the length (n) of the embedding goes to infinity, at least linearly in n. One example of a good measure of knot complexity is crossing number. Finally we consider similar questions for embeddings of graphs. We show that for a fixed homeomorphism type, as the number of edges n goes to infinity, almost all embeddings are knotted if the homeomorphism type does not contain a cut edge. We prove a weaker result in the case that the homeomorphism type contains at least one cut edge and at least one cycle.