Miracle-dz/UniFAR-FTUs huggingface dataset:
Magnetic order and interactions in ferrimagnetic Mn3Si2Te6

The magnetism in Mn$_3$Si$_2$Te$_6$ has been investigated using thermodynamic measurements, first principles calculations, neutron diffraction and diffuse neutron scattering on single crystals. These data confirm that Mn$_3$Si$_2$Te$_6$ is a ferrimagnet below a Curie temperature of $T_C$ approximately 78K. The magnetism is anisotropic, with magnetization and neutron diffraction demonstrating that the moments lie within the basal plane of the trigonal structure. The saturation magnetization of approximately 1.6$\mu_B$/Mn at 5K originates from the different multiplicities of the two antiferromagnetically-aligned Mn sites. First principles calculations reveal antiferromagnetic exchange for the three nearest Mn-Mn pairs, which leads to a competition between the ferrimagnetic ground state and three other magnetic configurations. The ferrimagnetic state results from the energy associated with the third-nearest neighbor interaction, and thus long-range interactions are essential for the observed behavior. Diffuse magnetic scattering is observed around the 002 Bragg reflection at 120K, which indicates the presence of strong spin correlations well above $T_C$. These are promoted by the competing ground states that result in a relative suppression of $T_C$, and may be associated with a small ferromagnetic component that produces anisotropic magnetism below $\approx$330K.
Mass density slope of elliptical galaxies from strong lensing and resolved stellar kinematics

We discuss constraints on the mass density distribution (parameterized as $\rho\propto r^{-\gamma}$) in early-type galaxies provided by strong lensing and stellar kinematics data. The constraints come from mass measurements at two `pinch' radii. One `pinch' radius $r_1=2.2 R_{Einst}$ is defined such that the Einstein (i.e. aperture) mass can be converted to the spherical mass almost independently of the mass-model. Another `pinch' radius $r_2=R_{opt}$ is chosen so that the dynamical mass, derived from the line-of-sight velocity dispersion, is least sensitive to the anisotropy of stellar orbits. We verified the performance of this approach on a sample of simulated elliptical galaxies and on a sample of 15 SLACS lens galaxies at $0.01 \leq z \leq 0.35$, which have already been analysed in Barnabe et al. (2011) by the self-consistent joint lensing and kinematic code. For massive simulated galaxies the density slope $\gamma$ is recovered with an accuracy of $\sim 13\%$, unless $r_1$ and $r_2$ happen to be close to each other. For SLACS galaxies, we found good overall agreement with the results of Barnabe et al. (2011) with a sample-averaged slope $\gamma=2.1\pm0.05$. While the two-pinch-radii approach has larger statistical uncertainties, it is much simpler and uses only few arithmetic operations with directly observable quantities.
Application of a full chain analysis using neutron monitor data for space weather studies

An important topic in the field of space weather is the precise assessment of the contribution of galactic cosmic rays and solar energetic particles on air crew exposure, specifically during eruptive events on the Sun. Here we present a model, a full chain analysis based on ground based measurements of cosmic rays with neutron monitors, subsequent derivation of particle spectral and angular characteristics and computation of dose rate. The model uses method for ground level enhancement analysis and newly numerically computed yield functions for conversion of secondary particle fluence to effective dose and/or the ambient dose equivalent. The precise an adequate information about the solar energetic particle spectra (SEPs) is the basis of the model. Since SEPs possess an essential isotropic part, specifically during the event onset, the angular characteristics should be also derived with good precision. This can be achieved using neutron monitor data during a special class of SEP events the ground level enhancements (GLEs). On the basis of the method representing a sequence of consecutive steps: computation of the NM asymptotic cones, NM rigidity cut-off and application of convenient optimization procedure, we derive the rigidity spectra and anisotropy characteristics of GLE particles. For the computation we use newly computed yield function of the standard sea-level 6NM64 neutron monitor for primary proton and alpha CR nuclei as well as 6NM64 yield function at altitudes ranging from the sea level up to 5000 m above the sea level. We derive the SEP spectra and pitch angle distributions in their dynamical development throughout the event. Subsequently on the basis of the derived spectra and angular characteristics and previously computed yield functions we calculate the effective dose and/or ambient dose equivalent during the GLE. Several examples are shown.
Physics of B_c mesons

Gershtein S.S. , Kiselev V.V. , Likhoded A.K. , Tkabladze A.V. Physics of Bc mesons: IHEP Preprint 94-81. – Protvino, 1994. – p. 82, figs. 23, tables 28. In the framework of potential models for heavy quarkonium the mass spectrum for the system (b̄c) is considered. Spin-dependent splittings, taking into account a change of a constant for effective coulomb interaction between the quarks, and widths of radiative transitions between the (b̄c) levels are calculated. In the framework of QCD sum rules, masses of the lightest vector B∗ c and pseudoscalar Bc states are estimated, scaling relation for leptonic constants of heavy quarkonia is derived, and the leptonic constant fBc is evaluated. The Bc decays are considered in the framework of both the potential models and the QCD sum rules, where the significance of Coulomb-like corrections is shown. The relations, following from the approximate spin symmetry for the heavy quarks in the heavy quarkonium, are analysed for the form factors of the semileptonic weak exclusive decays of Bc. The Bc lifetime is evaluated with the account of the corrections to the spectator mechanism of the decay, because of the quark binding into the meson. The total and differential cross sections of the Bc production in different interactions are calculated. The analytic expressions for the fragmentational production cross sections of Bc are derived. The possibility of the practical Bc search in the current and planning experiments at electron-positron and hadron colliders is analysed. c © Federal Science Centre Institute for High Energy Physics, 1994.
Which Are the Youngest Protostars? Determining Properties of Confirmed and Candidate Class 0 Sources by Broadband Photometry

We searched the literature to obtain a complete list of known Class 0 sources. A list of 95 confirmed or candidate objects was compiled. To the best of our knowledge, all published broadband observations from 1 μm to 3.5 mm have been collected and are assembled in a catalog. These data were used to determine physical properties (Tbol, Lbol, Lsmm/Lbol, Menv) and for a uniform classification. Fifty sources possess sufficient observational data and are classified as Class 0 or Class 0/1 objects. The source properties are compared with different evolutionary models to infer ages and masses, and their correlations are investigated. About 25% of the sources are found to be in a quiet accretion phase or possess a significantly different time evolution of the accretion rate than the average. In Taurus, with its isolated star formation mode, this seems especially to be the case.
The relationship between gender and academic performance in undergraduate physics students: the role of physics identity, perceived recognition, and self-efficacy

Studies focusing on physics undergraduate students have found that women tend not to identify as strongly with physics, compared to men. Recent research has examined potential factors that influence the experience of women in physics. Several of these factors, such as students’ beliefs in their ability to complete physics-based tasks (i.e., self-efficacy) and students’ belief that others perceive them as a physicist (i.e., perceived recognition), have been associated with physics identity in the context of introductory university physics courses in the United States (US). The current study extends this previous work, surveying students at all levels of the undergraduate degree at a research-intensive university in the UK. Students were asked about their physics identity, physics self-efficacy, and the extent to which they believed others perceived them as physicists. The survey responses were then matched with students’ grades. Using matched responses from the start and end of an academic year from 169 students (110 men, 59 women), two analyses were performed. The first analysis found that average scores for women for physics identity, and self-efficacy were lower than for men both at the start and end of the academic year. The second analysis found that after controlling for the start-of-year scores in physics identity, self-efficacy, and perceived recognition, students’ mid-year grades significantly predicted variance in their end-of-year scores for self-efficacy, perceived recognition, and (possibly also) physics identity. This study also found that the gap in perceived recognition between men and women increased over the academic year. The results contribute to understanding potential barriers for women in physics and have implications for instruction in terms of promoting students’ physics identity, self-efficacy, and perceived recognition.
Confirming the least massive members of the Pleiades star cluster

We present optical photometry (i- and Z-band) and low-resolution spectroscopy (640-1015 nm) of very faint candidate members (J = 20.2-21.2 mag) of the Pleiades star cluster (120 Myr). The main goal is to address their cluster membership via photometric, astrometric, and spectroscopic studies, and to determine the properties of the least massive population of the cluster through the comparison of the data with younger and older spectral counterparts and state-of-the art model atmospheres. We confirm three bona-fide Pleiades members that have extremely red optical and infrared colors, effective temperatures of ~1150 K and ~1350 K, and masses in the interval 11-20 Mjup, and one additional likely member that shares the same motion as the cluster but does not appear to be as red as the other members with similar brightness. This latter object requires further near-infrared spectroscopy to fully address its membership in the Pleiades. The optical spectra of two bona-fide members were classified as L6-L7 and show features of KI, a tentative detection of CsI, hydrides and water vapor with an intensity similar to high-gravity dwarfs of related classification despite their young age. The properties of the Pleiades L6-L7 members clearly indicate that very red colors of L dwarfs are not a direct evidence of ages younger than ~100 Myr. We also report on the determination of the bolometric corrections for the coolest Pleiades members. These data can be used to interpret the observations of the atmospheres of exoplanets orbiting stars.
CONSEQUENCES OF ELEVATED ATMOSPHERIC CO2 AND RELATED PHENOMENA ON PLANT LIFE

In this study, effects of elevated CO2 and associated phenomena such as increased atmospheric temperatures and nutrient deposition have been discussed in terms of plant growth and regeneration, population and biodiversity issues. Elevated CO2 may result in enhanced carbon sequestration to soil, though it is not clear if an increased soil carbon pool will contribute to higher plant productivity. However, there is evidence that an increased anthropogenic nitrogen deposition co-occurring with elevated CO2 may act as a missing sink for the excessive carbon in the ecosystem and thereby contribute to enhanced plant productivity. Although elevated CO2 may improve plant water use efficiency and reduce light compensation point for effective photosynthesis, associated effects of extreme temperatures may damage plant tissues, and consequently limit the survival of certain plant species in some regions. Rapid changes in climate may result in substantial tree mortality; as a consequence large expanses of forested regions may become increasingly dominated by early successional vegetation of small size which may suppress saplings of dominant canopy tree species. High resource availability associated with elevated CO2 may cause a smaller number of individuals to proportionately dominate biomass and reproductive output within a population that may act to reduce effective population size in genetic terms. Thus plant biodiversity will be affected due to rising CO2. However, speciation rates would be little affected due to shortness of the time scale.
Continuity of the percolation probability and chemical distances in inhomogeneous long-range percolation

Inhomogeneous long-range percolation on the lattice $\mathbb Z^d$ was introduced in Deijfen et al. (2013) as an extension of the homogeneous long-range percolation model. The inhomogeneous long-range percolation model assigns i.i. d. weights $W_x$ to each vertex $x\in \mathbb Z^d$. Conditionally on these weights, an edge between vertices $x$ and $y$ is occupied with probability $p_{xy}=1-\exp(-\lambda W_xW_y|x-y|^{-\alpha})$, independently of all other edges. Deijfen et al. (2013) provides the phase transition picture for the existence of an infinite component of occupied edges. In the present paper we complement this phase transition picture by proving that the percolation probability (as a function of $\lambda$)is continuous for $\alpha\in(d, 2d)$ and, therefore, there is no infinite component at criticality. Moreover, we complement the picture of Deijfen et al. (2013) about chemical distances in the infinite component.
The 10-meter Winter Wheat Mapping in Shandong Province Using Sentinel-2 Data and Coarse Resolution Maps

Timely and accurate large-scale mapping of the spread of winter wheat (Triticum aestivum) is crucial to guarantee food security, study climate change, and monitor operational agriculture. Traditional winter wheat mapping frameworks are constrained by insufficient spatial resolution and heavy dependence on field surveys, while traditional machine learning models excessively rely on subjective judgment. Furthermore, collecting sufficient field samples covering a large area is expensive and time-consuming. In this context, an automatic label update deep learning solution is developed to produce 10-m resolution winter wheat maps using Sentinel-2 data and existing coarse-resolution (30 m) winter wheat mapping products. In particular, a label update module considering the unique phenological (seasonal) characteristics of winter wheat is designed to update labels in the training phase. The results indicate that our method yields a satisfactory classification result with an overall accuracy exceeding 92% and an ${F}_{1}$ score greater than 0.85 for all validation samples, even when no field survey data were used for training. In addition, a 10-m spatial resolution winter wheat map for the entire Shandong province is generated, showing a significant correlation between the computed winter wheat map and the agricultural statistical land, with correlation coefficients of 0.95 and 0.78 at the municipal and county levels, respectively. The proposed methodology can serve as a viable and promising method for high-resolution, operational agricultural monitoring over large areas.
Hydrodynamic charge and heat transport on inhomogeneous curved spaces

We develop the theory of hydrodynamic charge and heat transport in strongly interacting quasi-relativistic systems on manifolds with inhomogeneous spatial curvature. In solid-state physics, this is analogous to strain disorder in the underlying lattice. In the hydrodynamic limit, we find that the thermal and electrical conductivities are dominated by viscous effects, and that the thermal conductivity is most sensitive to this disorder. We compare the effects of inhomogeneity in the spatial metric to inhomogeneity in the chemical potential, and discuss the extent to which our hydrodynamic theory is relevant for experimentally realizable condensed matter systems, including suspended graphene at the Dirac point.
Generalization of the separation principle beyond constant-gain state-feedback control

In the linear control community, the well-known separation principle states that, for a controller designed using an observer and a constant-gain state-feedback gain can be designed separately since the overall closed-loop system eigenvalues are the union of those due to the observer alone and those due to the state-feedback controller alone. In this note, we generalize the separation principle in two directions. First, we use eigenvalue calculations to show that the separation principle holds for dynamic controllers and not just constant-gain controllers; both dynamic state-feedback and dynamic output-feedback controllers are considered. Second, we use a simple linearity argument to argue that the separation principle holds, in fact, not just for the well-known observer structure, but for a whole class of asymptotic observers, including observers that are neither linear nor time-invariant. This paper includes radiotherapy control problem to illustrate the usefulness of these results.
Subjective Response to Foot-Fall Noise, Including Localization of the Source Position

Although an impact noise level is objectively evaluated the same according to current standards, a lightweight floor structure is often subjectively judged more annoying than a heavy homogeneous structure. The hypothesis of the present investigation is that the subjective judgment of impact noise is more annoying if the source position can be localized; lightweight structures have a more localized radiation than heavy structures. For the heavy structures the reverberant vibration field is dominant, therefore having a distributed radiation. A listening test is used to assess the subjective annoyance, using simulated binaural room impulse responses, with sources being a moving point source or a nonmoving surface source, and rooms being a room with a reverberation time of 0.5 s or an anechoic room. The paper concludes that no strong effect of the source localization on the annoyance can be found.
The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda,and w from the First Year Data Set

We present distance measurements to 71 high redshift type Ia supernovae discovered during the first year of the 5-year Supernova Legacy Survey (SNLS). These events were detected and their multi-color light-curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands. Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshift. With this data set, we have built a Hubble diagram extending to z = 1, with all distance measurements involving at least two bands. Systematic uncertainties are evaluated making use of the multiband photometry obtained at CFHT. Cosmological fits to this first year SNLS Hubble diagram give the following results: {Omega}{sub M} = 0.263 {+-} 0.042 (stat) {+-} 0.032 (sys) for a flat {Lambda}CDM model; and w = -1.023 {+-} 0.090 (stat) {+-} 0.054 (sys) for a flat cosmology with constant equation of state w when combined with the constraint from the recent Sloan Digital Sky Survey measurement of baryon acoustic oscillations.
Archives and records management strategies to support academic service delivery at the Universities of Witwatersrand and Universities of Venda

The purpose of this study was to investigate the alignment of archives and records management processes with the overall university management strategy. The South African universities’ strategies are not aligned with records management processes. A qualitative method was used to collect data from the source points through purposeful sampling. At both universities of Venda and Witwatersrand, the study revealed that records management is not align aligned with the university's broad strategy. The findings have practical implications for academic service delivery, governance, compliance and risk exposure. Other related institutions can also use the findings as a reference point in planning the implementation of similar studies.
New bounds on axionlike particles from the Fermi Large Area Telescope observation of PKS 2155 -304

The axionlike particle (ALP)-photon mixing in the magnetic field around gamma-ray sources or along the line of sight could induce oscillation between photons and ALPs, which then causes irregularities in the gamma-ray spectra. In this work we search for such spectral irregularities in the spectrum of PKS 2155 - 304 using 8.6 years of data from the Fermi Large Area Telescope (Fermi-LAT). No significant evidence for the presence of ALP-photon oscillation is obtained, and the parameter space of ALPs is constrained. The exclusion region sensitively depends on the poorly known magnetic field of the host galaxy cluster of PKS 2155 - 304. If the magnetic field is as high as similar to 10 mu G, the "holelike" parameter region allowed in Ref. [1] can be ruled out.
Cubic interactions in the BMN limit of AdS(3) x S(3)

Abstract We study the pp limit of AdS3 × S3 at the interaction level. We find the interacting Hamiltonian for the bosonic fields of D = 6 SUGRA in the pp-wave background, and compare it to the cubic couplings of the full AdS3 × S3. We show how the pp-wave theory vertex arises in the large J limit. Our analysis also provides some insight into the origin of specific “prefactors” which appear in the pp-wave interaction.
Merging black hole binaries: the effects of progenitor's metallicity, mass-loss rate and Eddington factor

The first four gravitational wave events detected by LIGO were all interpreted as merging black hole binaries (BHBs), opening a new perspective on the study of such systems. Here we use our new population-synthesis code MOBSE, an upgraded version of BSE (Hurley et al. 2002), to investigate the demography of merging BHBs. MOBSE includes metallicity-dependent prescriptions for mass loss of massive hot stars. It also accounts for the impact of the electron-scattering Eddington factor on mass loss. We perform >10^8 simulations of isolated massive binaries, with 12 different metallicities, to study the impact of mass loss, core-collapse supernovae and common envelope on merging BHBs. Accounting for the dependence of stellar winds on the Eddington factor leads to the formation of black holes (BHs) with mass up to 65 Msun at metallicity Z~0.0002. However, most BHs in merging BHBs have masses 0.6 are more likely. We predict that systems like GW150914, GW170814 and GW170104 can form only from progenitors with metallicity Z<=0.006, Z<=0.008 and Z<=0.012, respectively. Most merging BHBs have gone through a common envelope phase, but up to ~17 per cent merging BHBs at low metallicity did not undergo any common envelope phase. We find a much higher number of mergers from metal-poor progenitors than from metal-rich ones: the number of BHB mergers per unit mass is ~10^-4 Msun^-1 at low metallicity (Z = 0.0002 - 0.002) and drops to ~10^-7 Msun^-1 at high metallicity (Z ~ 0.02).