Miracle-dz/UniFAR-FTUs huggingface dataset:
An analog simulation experiment to study free oscillations of a damped simple pendulum

The characteristics of drive-free oscillations of a damped simple pendulum under sinusoidal potential force field differ from those of the damped harmonic oscillations. The frequency of oscillation of a large amplitude simple pendulum decreases with increasing amplitude. Many prototype mechanical simple pendulum have been fabricated with precision and studied earlier in view of introducing them in undergraduate physics laboratories. However, fabrication and maintenance of such mechanical pendulum require special skill. In this work, we set up an analog electronic simulation experiment to serve the purpose of studying the force-free oscillations of a damped simple pendulum. We present the details of the setup and some typical results of our experiment. The experiment is simple enough to implement in undergraduate physics laboratories.
Size dependence of effective Young’s modulus of nanoporous gold

Nanoporous gold (NPG) is a brittle, three-dimensional, random structure of Au with nanometer scale open porosity that is made by dealloying Au∕Ag alloys in acid. In this work, Young’s modulus of NPG with controlled porosity variation between 3 and 40nm is determined by mechanical testing of ∼100nm thick, free standing, large-grained, stress-free films of NPG using a buckling-based method [C. Stafford et al., Nat. Mater. 3, 545 (2005)]. Results showing a dramatic rise in the effective Young’s modulus of NPG with decreasing ligament size, especially below 10nm are presented, and possible reasons for this behavior are discussed.
Quantum computing with antiferromagnetic spin clusters

We show that a wide range of spin clusters with antiferromagnetic intracluster exchange interaction allows one to define a qubit. For these spin cluster qubits, initialization, quantum gate operation, and readout are possible using the same techniques as for single spins. Quantum gate operation for the spin cluster qubit does not require control over the intracluster exchange interaction. Electric and magnetic fields necessary to effect quantum gates need only be controlled on the length scale of the spin cluster rather than the scale for a single spin. Here, we calculate the energy gap separating the logical qubit states from the next excited state and the matrix elements which determine quantum gate operation times. We discuss spin cluster qubits formed by one- and two-dimensional arrays of s=1/2 spins as well as clusters formed by spins s<1/2. We illustrate the advantages of spin cluster qubits for various suggested implementations of spin qubits and analyze the scaling of decoherence time with spin cluster size.
MODIFIED NGUYEN AND REVOL’S METHOD FOR SOLUTION SET OF LINEAR INTERVAL SYSTEM BASED ON ROHN’S METHOD WITHOUT INTERVAL DATA INPUTS

The paper is a modificationofNguyen and Revol’s method for the solution set to the linear interval system. The presented methoddoes not require solving Kahan’s arithmetic which may be a hindrance to that of Nguyen and Revol’s method as Nguyen and Revol’s method relies mainly on interval data inputs.Our method under consideration first advances solutionusing real floating point LU Factorization to the real point linear system and then solves a preconditioned residual linear interval system for the error term by incorporating Rohn’s method which does not make use of interval data inputs wherein, the use of united solution set in the sense of Shary comes in handy as a tool for bounding solution for the linear interval system. Special attention is paid to the regularity of the preconditioned interval matrix. Numerical exampleis used to illustrate the algorithm and remarks are made based on the strength of our findings.
Formation of ultra-diffuse galaxies in the field and in galaxy groups

We study ultra-diffuse galaxies (UDGs) in zoom in cosmological simulations, seeking the origin of UDGs in the field versus galaxy groups. We find that while field UDGs arise from dwarfs in a characteristic mass range by multiple episodes of supernova feedback (Di Cintio et al.), group UDGs may also form by tidal puffing up and they become quiescent by ram-pressure stripping. The field and group UDGs share similar properties, independent of distance from the group centre. Their dark-matter haloes have ordinary spin parameters and centrally dominant dark-matter cores. Their stellar components tend to have a prolate shape with a Sérsic index n ∼ 1 but no significant rotation. Ram pressure removes the gas from the group UDGs when they are at pericentre, quenching star formation in them and making them redder. This generates a colour/star-formation-rate gradient with distance from the centre of the dense environment, as observed in clusters. We find that ∼20 per cent of the field UDGs that fall into a massive halo survive as satellite UDGs. In addition, normal field dwarfs on highly eccentric orbits can become UDGs near pericentre due to tidal puffing up, contributing about half of the group-UDG population. We interpret our findings using simple toy models, showing that gas stripping is mostly due to ram pressure rather than tides. We estimate that the energy deposited by tides in the bound component of a satellite over one orbit can cause significant puffing up provided that the orbit is sufficiently eccentric. We caution that while the simulations produce UDGs that match the observations, they under-produce the more compact dwarfs in the same mass range, possibly because of the high threshold for star formation or the strong feedback.
Coronal Abundances in Orion Nebula Cluster Stars

Following the Chandra Orion Ultradeep Project (COUP) observation, we have studied the chemical composition of the hot plasma in a sample of 146 X-ray-bright pre-main-sequence stars in the Orion Nebula Cluster (ONC). We report measurements of individual element abundances for a subsample of 86 slightly absorbed and bright X-ray sources, using low-resolution X-ray spectra obtained from the Chandra ACIS instrument. The X-ray emission originates from a plasma with temperatures and elemental abundances very similar to those of active coronae in older stars. A clear pattern of abundances versus first ionization potential (FIP) is evident if solar photospheric abundances are assumed as reference. The results are validated by extensive simulations. The observed abundance distributions are compatible with a single pattern of abundances for all stars, although a weak dependence on flare loop size may be present. The abundance of calcium is the only one which appears to vary substantially between stars, but this quantity is affected by relatively large uncertainties. The ensemble properties of the X-ray-bright COUP sources confirm that the iron in the emitting plasma is underabundant with respect to both the solar composition and the average stellar photospheric values. Comparison of the present plasma abundances with those of the stellar photospheres and those of the gaseous component of the nebula indicates a good agreement for all the other elements with available measurements, and in particular for the high-FIP elements (Ne, Ar, O, and S) and for the low-FIP element Si. We conclude that there is evidence of a significant chemical fractionation effect only for iron, which appears to be depleted by a factor 1.5-3 with respect to the stellar composition.
Deep Learning for Scientific Inference from Geophysical Data: The Madden-Julian Oscillation as a Test Case

Deep learning can recognize complex geophysical phenomena by inferring which variables are important for their identification and understanding their spatial characteristics. We use a particular mode of multi-scale tropical atmospheric variability, the Madden-Julian oscillation (MJO), to study the capabilities of deep learning, a form of artificial intelligence and machine learning, in identifying spatial geophysical phenomena. The MJO is characterized by its spatial and temporal evolution of cloud patterns, and an extensive body of literature has examined its defining characteristics. By applying a convolutional neural network (CNN), a type of deep learning model, to the task of identifying the state of the MJO, we show that deep learning can correctly identify geophysical phenomena by "learning" the variables and spatial patterns important to their evolution. In a broader sense, these findings suggest that deep learning models are interpretable and viable for scientific inference in geoscientific applications.
Anomalous lattice contraction and emergent electronic phases in Bi-doped 
Eu2Ir2O7

We study the pyrochlore series (${\mathrm{Eu}}_{1\ensuremath{-}x}{\mathrm{Bi}}_{x}{)}_{2}{\mathrm{Ir}}_{2}{\mathrm{O}}_{7}$ for $0\ensuremath{\le}x\ensuremath{\le}1$. We show that for small $x$, the lattice undergoes an anomalous contraction but the time reversal symmetry breaking all-in/all-out state remains robust and the resistivity approaches a $1/T$ dependence at low $T$, suggesting proximity to the Weyl semimetallic phase. At the boundary near 10% Bi doping, a qualitatively different ground state emerges, which is characterized by a metallic behavior and the absence of magnetic ordering at least down to $0.02\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. For higher Bi doping, the resistivity remains metallic, and evolves gradually from $T$ linear to ${T}^{2}$ to ${T}^{3/2}$, suggesting the possibilities of myriad different electronic phases between ${\mathrm{Eu}}_{2}{\mathrm{Ir}}_{2}{\mathrm{O}}_{7}$ and ${\mathrm{Bi}}_{2}{\mathrm{Ir}}_{2}{\mathrm{O}}_{7}$.
Dynamics of a Free-Clamped Cylinder in Confined Axial Flow

The dynamics of a flexible cantilevered cylinder in confined axial flow is studied theoretically and experimentally, in the case where the flow is directed from the free end towards the clamped end. First, the dynamics is described, as observed in specially conducted experiments with air flow; the system developed small-amplitude first-mode vibrations at low flow velocities, which could be flutter, and at higher flows the oscillatory behaviour was succeeded by a static divergence. A simple, linear theoretical model is also developed, and the theoretically predicted behaviour is compared to the experimental one. The model captures the essentials of the observed behaviour, but requires improvement before quantitative prediction can be considered to be adequate.Copyright © 2011 by ASME
Molecular Gas in the Inner 3.2 Kiloparsecs of NGC 2403: Star Formation at Subcritical Gas Surface Densities

We present a fully sampled map of the inner 3.2 kpc of the nearby spiral galaxy NGC 2403 in the CO J=1-0 line. These data emphasize the relatively small contribution of molecular hydrogen to the cold gas content of this galaxy, and confirm that the gas surface densities in the inner 2.8 kpc of NGC 2403 lie below the critical surface density for star formation under the theory proposed by Kennicutt (1989). Since star formation is occurring throughout the inner disk, the simple dynamical model used by Kennicutt cannot be the only important process regulating star formation in galaxies. We suggest that stochastic star formation processes are responsible for the star formation seen in these regions, and thus that supercritical gas densities may not be a necessary condition for star formation in the inner regions of galactic disks.
Accurate measurement and evaluation of dynamic characteristics of flying head slider for large-capacity fast-access magnetic disk storage

For large-capacity fast-access magnetic disk storage, a flying head slider with less than 0.2 μm spacing has been developed to achieve a high recording density of 62 kbit/mm2. In attaining higher recording density, it is exceedingly important to minimize spacing and suppress fluctuation. Consequently, accurate spacing measurement and evaluation of slider dynamic characteristics become the most important preconditions for achieving high performance equipment. This paper presents a highly accurate method of measuring spacing over a wide frequency range using visible laser interferometry. Methods for evaluating slider dynamic response due to three types of excitation are presented. Good agreement is obtained between experimental and numerical results. It is clarified that this slider system has a highly dynamic performance. Additionally, it is also confirmed that the modified Reynolds equation is quite suitable for predicting slider dynamic response accurately even at very low 0.1 μm spacing.
The clustering of typical Ly α emitters from z ∼ 2.5–6: host halo masses depend on Ly α and UV luminosities

We investigate the clustering and halo properties of ∼5000 Ly α-selected emission-line galaxies (LAEs) from the Slicing COSMOS 4K (SC4K) and from archival NB497 imaging of SA22 split in 15 discrete redshift slices between z ∼ 2.5 and 6. We measure clustering lengths of r0 ∼ 3–6 h−1 Mpc and typical halo masses of ∼1011 M⊙ for our narrowband-selected LAEs with typical LLy α ∼ 1042–43 erg s−1. The intermediate-band-selected LAEs are observed to have r0 ∼ 3.5–15 h−1 Mpc with typical halo masses of ∼1011–12 M⊙ and typical LLy α ∼ 1043–43.6 erg s−1. We find a strong, redshift-independent correlation between halo mass and Ly α luminosity normalized by the characteristic Ly α luminosity, L⋆(z). The faintest LAEs (L ∼ 0.1 L⋆(z)) typically identified by deep narrowband surveys are found in 1010 M⊙ haloes and the brightest LAEs (L ∼ 7 L⋆(z)) are found in ∼5 × 1012 M⊙ haloes. A dependency on the rest-frame 1500 Å UV luminosity, MUV, is also observed where the halo masses increase from 1011 to 1013 M⊙ for MUV ∼ −19 to −23.5 mag. Halo mass is also observed to increase from 109.8 to 1012 M⊙ for dust-corrected UV star formation rates from ∼0.6 to 10 M⊙ yr−1 and continues to increase up to 1013 M⊙ in halo mass, where the majority of those sources are active galactic nuclei. All the trends we observe are found to be redshift independent. Our results reveal that LAEs are the likely progenitors of a wide range of galaxies depending on their luminosity, from dwarf-like, to Milky Way-type, to bright cluster galaxies. LAEs therefore provide unique insight into the early formation and evolution of the galaxies we observe in the local Universe.
Thermonuclear fusion rates for tritium + deuterium using Bayesian methods

The H3(d,n)He4 reaction has a large low-energy cross section and will likely be utilized in future commercial fusion reactors. This reaction also takes place during Big Bang nucleosynthesis. Studies of both scenarios require accurate and precise fusion rates. To this end, we implement a one-level, two-channel R-matrix approximation into a Bayesian model. Our main goals are to predict reliable astrophysical S-factors and to estimate R-matrix parameters using the Bayesian approach. All relevant parameters are sampled in our study, including the channel radii, boundary condition parameters, and data set normalization factors. In addition, we take uncertainties in both measured bombarding energies and S-factors rigorously into account. Thermonuclear rates and reactivities of the H3(d,n)He4 reaction are derived by numerically integrating the Bayesian S-factor samples. The present reaction rate uncertainties at temperatures between 1.0 MK and 1.0 GK are in the range of 0.2% to 0.6%. Our reaction rates differ from previous results by 2.9% near 1.0 GK. Our reactivities are smaller than previous results, with a maximum deviation of 2.9% near a thermal energy of 4 keV. The present rate or reactivity uncertainties are more reliable compared to previous studies that did not include the channel radii, boundary condition parameters, and data set normalization factors in the fitting. Finally, we investigate previous claims of electron screening effects in the published H3(d,n)He4 data. No such effects are evident and only an upper limit for the electron screening potential can be obtained.
The XMM-Newton/2dF survey - II. The nature of X-ray - faint optically bright X-ray sources

In this paper we investigate the properties of low X-ray-to-optical flux ratio sources detected in a wide-area (2.5 deg 2 ) shallow [f X (0.5-8 keV) 10 -14 erg s -1 cm -2 ] XMM-Newton survey. We find a total of 26 sources (5 per cent of the total X-ray-selected population) with log f X /f opt < -0.9 to the above flux limit. Optical spectroscopy is available for 20 of these low X-ray-to-optical flux ratio objects. Most of them are found to be associated with Galactic stars (a total of eight) and broad-line active galactic nuclei (AGNs; a total of eight). We also find two sources with optical spectra showing absorption and/or narrow emission lines and X-ray/optical properties suggesting AGN activity. Another two sources are found to be associated with low-redshift galaxies with narrow emission-line optical spectra, X-ray luminosities L X (0.5-8 keV) 10 41 erg s -1 and log f X /f opt -2 suggesting 'normal' star-forming galaxies. Despite the small-number statistics the sky density of 'normal' X-ray-selected star-forming galaxies at the flux limit of the present sample is low, consistent with previous ROSAT High-Resolution Imager (HRI) deep surveys. Also, the number density estimated here is in good agreement with both the log N-log S of 'normal' galaxies in the Chandra Deep Field North (extrapolated to bright fluxes) and model predictions based on the X-ray luminosity function of local star-forming galaxies.
Combination of apatinib mesylate and second-line chemotherapy for treating gastroesophageal junction adenocarcinoma

Objective To investigate the safety and efficacy of acitinib mesylate combined with chemotherapy in the treatment of patients with gastroesophageal junction adenocarcinoma. Methods A total of 119 patients with gastroesophageal junction adenocarcinoma were enrolled and randomized into an experimental group (n = 60) and a control group (n = 59). Both groups were treated with a combination of taxane, irinotecan and fluorouracil, while the experimental group also received acitinib mesylate. The clinical efficacy, survival time and adverse reactions of patients in two groups were recorded and analyzed. Results The total remission rate in the experimental group and the control group was 15.79% and 3.23%, respectively; the disease control rate was 73.68% and 54.84%, respectively; and progression-free survival was 3.72 months (1–13.5 months) and 3.04 months (1–6 months), respectively. Overall survival was 13.66 months (5–24 months) and 10.08 months (6.5–19.5 months), in the experimental group and the control group, respectively. In addition, the incidence of adverse events in the experimental group was significantly lower than that in the control group. Conclusion Apatinib mesylate combined with chemotherapy for the treatment of patients with gastroesophageal junction adenocarcinoma was safe and effective, with improved survival benefit compared with control.
Dynamics of vortex core switching in ferromagnetic nanodisks

Dynamics of magnetic vortex core switching in nanometer-scale Permalloy disk, having a single vortex ground state, was investigated by micromagnetic modeling. When an in-plane magnetic field pulse with an appropriate strength and duration is applied to the vortex structure, additional two vortices, i.e., a circular and an antivortex, are created near the original vortex core. Sequentially, the vortex-antivortex pair annihilates. A spin wave is created at the annihilation point and propagated through the entire element; the relaxed state for the system is the single vortex state with a switched vortex core.
Supernova Nucleosynthesis in Population III 13-50 M☉ Stars and Abundance Patterns of Extremely Metal-poor Stars

We perform hydrodynamic and nucleosynthesis calculations of core-collapse supernovae (SNe) and hypernovae (HNe) of Population (Pop) III stars. We provide new yields for the main-sequence mass of MMS = 13-50 M☉ and the explosion energy of E = (1–40) × 1051 ergs to apply to chemical evolution studies. Our HN yields based on the mixing-fallback model of explosions reproduce the observed abundance patterns of extremely metal-poor (EMP) stars (-4 < [Fe/H] < -3), while those of very metal-poor (VMP) stars (-3 < [Fe/H] < -2) are reproduced by the normal SN yields integrated over the Salpeter initial mass function. Moreover, the observed trends of abundance ratios [X/Fe] against [Fe/H] with small dispersions for the EMP stars can be reproduced as a sequence resulting from the various combination of MMS and E. This is because we adopt the empirical relation that a larger amount of Fe is ejected by more massive HNe. Our results imply that the observed trends with small dispersions do not necessarily mean the rapid homogeneous mixing in the early Galactic halo at [Fe/H] < -3 but can be reproduced by the "inhomogeneous" chemical evolution model. In addition, we examine how the modifications of the distributions of the electron mole fraction Ye and the density in the presupernova models improve the agreement with observations. In this connection, we discuss possible contributions of nucleosynthesis in the neutrino-driven wind and the accretion disk.
Asymptomatic Cerebral Small Vessel Disease: Insights from Population-Based Studies

Cerebral small vessel disease (CSVD) is a common group of neurological conditions that confer a significant burden of morbidity and mortality worldwide. In most cases, CSVD is only recognized in its advanced stages once its symptomatic sequelae develop. However, its significance in asymptomatic healthy populations remains poorly defined. In population-based studies of presumed healthy elderly individuals, CSVD neuroimaging markers including white matter hyperintensities, lacunes, cerebral microbleeds, enlarged perivascular spaces, cortical superficial siderosis, and cerebral microinfarcts are frequently detected. While the presence of these imaging markers may reflect unique mechanisms at play, there are likely shared pathways underlying CSVD. Herein, we aim to assess the etiology and significance of these individual biomarkers by focusing in asymptomatic populations at an epidemiological level. By primarily examining population-based studies, we explore the risk factors that are involved in the formation and progression of these biomarkers. Through a critical semi-systematic review, we aim to characterize “asymptomatic” CSVD, review screening modalities, and draw associations from observational studies in clinical populations. Lastly, we highlight areas of research (including therapeutic approaches) in which further investigation is needed to better understand asymptomatic CSVD.
Wrapping Current versus Bulk Integer Quantum Hall Effect in Three Dimensions

Surface electron currents are studied for the integer quantum Hall effect in three dimensions (3D) proposed previously by Kohmoto et al. [Phys. Rev. B 45, 13 488 (1992)] and by Koshino et al. [Phys. Rev. Lett. 86, 1062 (2001)]. We predict that the current wraps the facets of the sample with its intensity and direction dictated by 3D Chern numbers that are just the quantized Hall conductivities in 3D (σ x y ,σ z x ), so a natural connection exists between the surface and bulk currents just as in 2D. An experiment to detect the 3D integer quantum Hall effect through the wrapping current is proposed.