Miracle-dz/UniFAR-FTUs huggingface dataset:
Stochastic exclusion processes versus coherent transport

Stochastic exclusion processes play an integral role in the physics of non-equilibrium statistical mechanics. These models are Markovian processes, described by a classical master equation. In this paper, a quantum mechanical version of a stochastic hopping process in one dimension is formulated in terms of a quantum master equation. This allows the investigation of coherent and stochastic evolution in the same formal framework. The focus lies on the non-equilibrium steady state. Two stochastic model systems are considered: the totally asymmetric exclusion process and the fully symmetric exclusion process. The steady-state transport properties of these models are compared to the case with additional coherent evolution, generated by the XX Hamiltonian.
On the correlation between metallicity and the X-shaped morphology of the Milky Way bulge

We demonstrate that failure to properly account for stellar evolution can bias results in determinations of the spatial morphology of Galactic bulge stars, focusing on the question of whether or not the X-shape is more pronounced among the more metal-rich stars than among the metal-poor stars. We argue that this trend, a result recently claimed by three separate groups, may have been overestimated as it is relatively easier to detect a bimodality in the distance distribution function at higher metallicities. This is due to three factors. First, the intrinsic colour of red clump and red giant stars vary with metallicity, at the level d(V-I)_{RC}/d\[M/H] ~ 0.25 mag dex^{-1}, and thus the ratio of red clump to red giant stars within a spectroscopic sample will depend on the photometric selection of any investigation. Second, the duration of ascent of the red giant branch goes down and the red clump lifetime goes up as metallicity increases, which has the effect of increasing the ratio of red clump to red giant stars by as much as ~33% over the range of the bulge metallicity-distribution function. Finally, over the same metallicity interval, the effective number of red giant branch bump stars is predicted to increase by ~200%, and their presence becomes degenerate with the observational parameters of the two red clumps, creating an illusory increase in signal-to-noise for a second peak in the distance modulus distribution.
Dynamic pricing in the presence of strategic consumers with ‘experience-in-store-and-buy-online’

Experience-in-store-and-buy-online (ESBO) is a popular omni-channel strategy. This paper studies the effects of inspection service provision on the interactions of a dynamic-pricing retailer and strategic consumers, i.e., the effects of the ESBO initiative on store operations. Selling a seasonal product over two periods, the omni-channel retailer may allow consumers to inspect this product offline only in the first period (first-period inspection) or in both periods (two-period inspection). First, we find that allowing first-period inspection makes the retailer better off. The retailer will price the product higher in the first period but probably lower in the second period. Even so, more consumers will purchase in the first period: that is, allowing first-period inspection can somewhat deter strategic deferral. Meanwhile, the seemingly negative intertemporal showrooming behavior (i.e., inspect the product offline in the first period but defer online purchase to the second period) benefits the retailer. Compared to first-period inspection, allowing two-period inspection increases the retailer’s prices in both periods as well as profit, provided that inspection is definitely available in the second period. On the other hand, when inspection is possible in the second period, it may be profitable to allow inspection only in the first period.
The magnetorotational instability as a jet launching mechanism

Magnetorotational turbulence and magnetically driven disc winds are often considered as separate processes. However, realistic astrophysical discs are expected to be subject to both effects, although possibly at different times and locations. We investigate here the potential link between these two phenomena using a mixed numerical and analytical approach. We show in particular that largescale magnetorotational instability modes which dominate strongly magnetised discs (plasma β ∼ 10) naturally produce magnetically driven outflows in the nonlinear regime. We show that these outflows share many similarities with local and global disc wind solutions found in the literature. We also investigate the 3D stability of these outflows and show that they are unstable on dynamical timescales. The implications of these results for the transition between a jet-emitting disc and a standard “viscous” disc are discussed.
The SAMI Galaxy Survey: shocks and outflows in a normal star-forming galaxy

We demonstrate the feasibility and potential of using large integral field spectroscopic surveys to investigate the prevalence of galactic-scale outflows in the local Universe. Using integral field data from SAMI and the Wide Field Spectrograph, we study the nature of an isolated disk galaxy, SDSS J090005.05+000446.7 (z = 0.05386). In the integral field datasets, the galaxy presents skewed line profiles changing with position in the galaxy. The skewed line profiles are caused by different kinematic components overlapping in the line-of-sight direction. We perform spectral decomposition to separate the line profiles in each spatial pixel as combinations of (1) a narrow kinematic component consistent with HII regions, (2) a broad kinematic component consistent with shock excitation, and (3) an intermediate component consistent with shock excitation and photoionisation mixing. The three kinematic components have distinctly different velocity fields, velocity dispersions, line ratios, and electron densities. We model the line ratios, velocity dispersions, and electron densities with our MAPPINGS IV shock and photoionisation models, and we reach remarkable agreement between the data and the models. The models demonstrate that the different emission line properties are caused by major galactic outflows that introduce shock excitation in addition to photoionisation by star-forming activities. Interstellar shocks embedded in the outflows shock-excite and compress the gas, causing the elevated line ratios, velocity dispersions, and electron densities observed in the broad kinematic component. We argue from energy considerations that, with the lack of a powerful active galactic nucleus, the outflows are likely to be driven by starburst activities. Our results set a benchmark of the type of analysis that can be achieved by the SAMI Galaxy Survey on large numbers of galaxies.
Field theory for zero sound and ion acoustic wave in astrophysical matter

We set up a field theory model to describe the longitudinal low energy modes in high density matter present in white dwarf stars. At the relevant scales, ions -- the nuclei of oxygen, carbon and helium -- are treated as heavy point-like spin-0 charged particles in an effective field theory approach, while the electron dynamics is described by the Dirac Lagrangian at the one-loop level. We show that there always exists a longitudinal gapless mode in the system irrespective whether the ions are in a plasma, crystal, or quantum liquid state. For certain values of the parameters, the gapless mode can be interpreted as a zero sound mode and, for other values, as an ion acoustic wave; we show that the zero sound and ion acoustic wave are complementary to each other. We discuss possible physical consequences of these modes for properties of white dwarfs.
Technology Advancements and Employees’ Qualitative Job Insecurity in the Republic of Korea: Does Training Help? Employer-Provided vs. Self-Paid Training

While technological advancements have proliferated in our daily lives, they also pose threats to the job security of employees. Despite these growing concerns about technology-related job insecurity, little research has been carried out on the antecedents and outcomes of tech-related job insecurity. Using a cross-sectional, nationally representative survey sample of 28,989 Korean workers drawn from the Korean Working Conditions Survey, we examined the impacts of technology advancements on employee perceptions of technology-related qualitative job insecurity (i.e., perceived technology-related threat to the continued existence of valued job features) and subsequent effects on employees’ work (i.e., work engagement, job satisfaction), health (i.e., sleep), and life (i.e., work-to-family conflict) outcomes. Furthermore, we investigated the extent to which employer-provided (versus self-funded) training buffers the adverse impacts of technology advancements and associated job insecurity. The path analysis results showed more technology changes were associated with higher job insecurity, which subsequently related to adverse outcomes. While employer-provided training helped workers to reduce the negative impacts of tech changes on job insecurity, workers who paid for their training reported more adverse outcomes in face of job insecurity. We discuss these results in light of the job demands–resources theory and practical implications to buffer the adverse impacts of technology advancements.
Orientation-dependent ionization yields from strong-field ionization of fixed-in-space linear and asymmetric top molecules

The yield of strong-field ionization, by a linearly polarized probe pulse, is studied experimentally and theoretically as a function of the relative orientation between the laser field and the molecule. Experimentally, carbonyl sulphide (OCS), benzonitrile and naphthalene molecules are aligned in one or three dimensions before being singly ionized by a 30 fs laser pulse centred at 800 nm. Theoretically, we address the behaviour of these three molecules. We consider the degree of alignment and orientation and model the angular dependence of the total ionization yield by molecular tunnelling theory accounting for the Stark shift of the energy level of the ionizing orbital. For naphthalene and benzonitrile, the orientational dependence of the ionization yield agrees well with the calculated results, in particular, we observe that ionization is maximized when the probe laser is polarized along the most polarizable axis. For OCS the observation of the maximum ionization yield when the probe is perpendicular to the internuclear axis contrasts the theoretical results.
Torque Ripple Suppression for Standalone Brushless Doubly-Fed Induction Generator-DC System Based on Power Winding Harmonic Current Control

The brushless doubly-fed induction generator-dc (BDFIG-DC) system has received more and more attentions with the cost-effective and efficient topology in recent years. However, it suffers from the torque ripple due to the distorted flux and current caused by the diode rectifier, which reduces the mechanical reliability of the system. In order to address this issue, this article proposes a torque ripple suppression method based on the power winding (PW) harmonic current control. Compared with the traditional method, the proposed method takes the sixth and twelfth harmonic components of the torque generated by the fifth and seventh harmonic fluxes and currents into account, which can maximize the torque ripple suppression effect of all the controllable PW harmonic currents. Besides, it is with the simpler control algorithm and higher robustness. Comprehensive experimental results based on a 5-kVA BDFIG demonstrate the effectiveness of the proposed method.
Random walk of magnetic field-lines for different values of the energy range spectral index

An analytical nonlinear description of field-line wandering in partially statistically magnetic systems was proposed recently. In this article the influence of the wave spectrum in the energy range onto field-line random walk is investigated by applying this formulation. It is demonstrated that in all considered cases we clearly obtain a superdiffusive behavior of the field-lines. If the energy range spectral index exceeds unity a free-streaming behavior of the field-lines can be found for all relevant length-scales of turbulence. Since the superdiffusive results obtained for the slab model are exact, it seems that superdiffusion is the normal behavior of field-line wandering.
Systematic variation of the stellar initial mass function with velocity dispersion in early-type galaxies

An essential component of galaxy formation theory is the stellarinitial mass function (IMF) that describes the parent distribution ofstellar mass in star-forming regions. We present observational evidence in a sample of early-type galaxies (ETGs) of a tight correlation between central velocity dispersion and the strength of several absorption features sensitive to the presence of low-mass stars. Our samplecomprises ~40 000 ETGs from the Spheroids Panchromatic Investigation in Different Environmental Regions survey (z ∼ 0.1). The data-extracted from the Sloan Digital Sky Survey-are combined, rejecting both noisy data, and spectra with contamination from telluric lines, resulting in a set of 18 stacked spectra at high signal-to-noise ratio (S/N ≳ 400a-1). A combined analysis of IMF-sensitive line strengths and spectral fitting is performed with the latest state-of-the-art population synthesis models (an extended version of the MILES models). Asignificant trend is found between IMF slope and velocity dispersion, towards an excess of low-mass stars in the most massive galaxies. Although we emphasize that accurate values of the IMF slope will requirea detailed analysis of chemical composition (such as [α/Fe] or even individual element abundance ratios), the observed trends suggest thatlow-mass ETGs are better fitted by a Kroupa-like IMF, whereas massivegalaxies require bottom-heavy IMFs, exceeding the Salpeter slope at σ ≳ 200 km s-1. © 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.
Single-electron quantum dot in Si∕SiGe with integrated charge sensing

Single-electron occupation is an essential component to the measurement and manipulation of spin in quantum dots, capabilities that are important for quantum information processing. Si∕SiGe is of interest for semiconductor spin qubits, but single-electron quantum dots have not yet been achieved in this system. We report the fabrication and measurement of a top-gated quantum dot occupied by a single electron in a Si∕SiGe heterostructure. Transport through the quantum dot is directly correlated with charge sensing from an integrated quantum point contact, and this charge sensing is used to confirm single-electron occupancy in the quantum dot.
The Faintest Galaxies

We investigate the nature of ultra faint dwarf spheroidal galaxies (UF dSphs) in a general cosmological context, simultaneously accounting for various ``classical'' dSphs and Milky Way (MW) properties, including their metallicity distribution function (MDF). Our model successfully reproduces both the observed [Fe/H]-luminosity relation and the mean MDF of UFs. According to our results, UFs are the living fossils of H2-cooling minihalos formed at z>8.5, i.e. before the end of reionization. They are the oldest and the most dark matter-dominated (M/L>100) dSphs in the MW system, with total masses of M = 107-8 Msolar. The model allows us to interpret the different shapes of UF and classical dSph MDFs along with the frequency of extremely metal-poor stars in these objects. We discuss the ``missing satellites problem'' by comparing UF star formation efficiencies with those derived for minihalos in the Via Lactea simulation.
Dynamic panel investigation of the determinants of South African commercial banks’ operational efficiency

Like any other business, commercial banks are greatly affected by the micro and macro-environment that operate in, no matter how large they are. Capital adequacy ratio, credit risk, money supply, inflation, the exchange rate, and the national gross domestic product have been noted to be the key determinants of bank operational efficiency. This research study looked at the operational efficiency of four large South African banks, namely, Standard Bank, Absa, Nedbank, and First National Bank. A quantitative, descriptive, correlation design was employed, and the System-Generalized Method of Moments (SYS-GMM) techniques were used and revealed that operational efficiency was positively correlated with capital adequacy ratio, credit risk, inflation, and exchange rate, and negatively correlated with profitability, money supply and GDP. SYS-GMM estimates show that capital adequacy ratio, credit risk, inflation and exchange rate positively influenced operational efficiency, while profitability, money supply (M3) and GDP had a negative influence. Thus, it is concluded that bank management should decrease administrative costs, evaluate customers’ creditworthiness before issuing loans, raise bank size as operational conditions require, boost intermediation, and anticipate inflation to operate more efficiently.
The stellar accretion origin of stellar population gradients in massive galaxies at large radii

We investigate the evolution of stellar population gradients from z = 2 to z = 0 in massive galaxies at large radii (r > 2Reff) using ten cosmological zoom simulations of halos with 6 × 10 12 M⊙ < Mhalo < 2 × 10 13 M⊙. The simulations follow metal cooling and enrichment from SNII, SNIa and AGB winds. We explore the differential impact of an empirical model for galactic winds that reproduces the mass-metallicity relation and its evolution with redshift. At larger radii the galaxies, for both models, become more dominated by stars accreted from satellite galaxies in major and minor mergers. In the wind model, fewer stars are accreted, but they are significantly more metal poor resulting in steep global metallicity (h∇Zstarsi = −0.35 dex/dex) and color (e.g. h∇g − ri = −0.13 dex/dex) gradients in agreement with observations. In contrast, colour and metallicity gradients of the models without winds are inconsistent with observations. Age gradients are in general mildly positive at z = 0 (h∇Agestarsi= 0.04 dex/dex) with significant differences between the models at higher redshift. We demonstrate that for the wind model, stellar accretion is steepening existing in-situ metallicity gradients by about 0.2 dex by the present day and helps to match observed gradients of massive early-type galaxies at large radii. Colour and metallicity gradients are significantly steeper for systems which have accreted stars in minor mergers, while galaxies with major mergers have relatively flat gradients, confirming previous results. This study highlights the importance of stellar accretion for stellar population properties of massive galaxies at large radii, which can provide important constraints for formation models.
Photometric metallicity calibration with SDSS and SCUSS and its application to distant stars in the south Galactic cap

Based on Sloan Digital Sky Survey (SDSS) g, r and South Galactic Cap of u-band Sky Survey (SCUSS) u photometry, we develop a photometric calibration for estimating the stellar metallicity from u - g and g - r colours by using the SDSS spectra of 32 542 F-and G-type main-sequence stars, which cover almost 3700 deg(2) in the south Galactic cap. The rms scatter of the photometric metallicity residuals relative to spectrum-based metallicity is 0.14 dex when g - r 0.4. Because of the deeper and more accurate magnitude of SCUSS u band, the estimate can be used up to the faint magnitude of g = 21. This application range of photometric metallicity calibration is wide enough so that it can be used to study metallicity distribution of distant stars. In this study, we select the Sagittarius (Sgr) stream and its neighbouring field halo stars in south Galactic cap to study their metallicity distribution. We find that the Sgr stream at the cylindrical Galactocentric coordinate of R similar to 19 kpc, vertical bar z vertical bar similar to 14 kpc exhibits a relative rich metallicity distribution, and the neighbouring field halo stars in our studied fields can be modelled by two-Gaussian model, with peaks, respectively, at [Fe/H] = -1.9 and -1.5.
Optimal Quantum Estimation for Gravitation

Here we describe the quantum limit to measurement of the classical gravitational field. Specifically, we write down the optimal quantum Cramer-Rao lower bound, for any single parameter describing a metric for spacetime. The standard time-energy and Heisenberg uncertainty relations are shown to be special cases of the uncertainty relation for the spacetime metric. Four key examples are given, describing quantum limited estimation for: acceleration, black holes, gravitational waves and cosmology. We employ the locally covariant formulation of quantum field theory in curved spacetime, which allows for a manifestly spacetime independent derivation. The result is an uncertainty relation applicable to all causal spacetime manifolds.
Peer Grading Eliciting Truthfulness Based on Autograder

Peer grading has diverse applications in many fields, including the peer grading of open assignments in online courses. The major challenge in peer grading is improving the seriousness (reviewing carefully) of reviewers. Previous studies have proposed several incentive reward mechanisms intended to reward or punish reviewers. Although these mechanisms are effective in massive open online courses environments with a large number of students, they are not suitable for small private online courses (SPOCs) environments with a small number of students. This article analyzes the characteristics of reviewers in a small private online course environment and designs an incentive and reward mechanism based on a hybrid human–machine peer grading framework, including an autograder (reviewed by the machine). The main component of the proposed mechanism is the autograder whose function is to evaluate the reviewers’ reports (reviewers refer to students) and provide feedback information on reports to reviewers. The framework can incentivize reviewers to review carefully and give their reports truthfully when the reports between reviewers’ and the autograder’ are consistent. The proposed framework is verified experimentally. The experimental results demonstrate that the hybrid human–machine peer grading framework can effectively incentivize reviewers to review submissions carefully and improve the overall effect of peer grading.
Predictors of Death in Patients with Neonatal Sepsis in a Peruvian Hospital

Reducing neonatal mortality is a global challenge. This study’s objective was to determine the predictors of mortality in patients with neonatal sepsis. The study was a retrospective cohort study in a Peruvian hospital from January 2014 to April 2022. Neonates diagnosed with sepsis were included. To find predictors of mortality, we used Cox proportional regression models. We evaluated 288 neonates with sepsis; the median birth weight and hospitalization time were 3270 g and seven days, respectively. During follow-up, 18.4% did not survive, and the most common complications were jaundice (35.42%), respiratory distress syndrome (29.51%), and septic shock (12.5%). The most isolated bacteria were Klebsiella pneumoniae. The risk factors associated with higher mortality were prematurity (aHR = 13.92; 95% CI: 1.71–113.51), platelets <150,000 (aHR = 3.64; 1.22–10.88), creatinine greater than 1.10 (aHR = 3.03; 1.09–8.45), septic shock (aHR = 4.41; 2.23–8.74), and admission to IMV (aHR = 5.61; 1.86–16.88), On the other hand, breastfeeding was associated with a lower risk of death (aHR = 0.25; 0.13–0.48). In conclusion, we report a high incidence of death and identify clinical (prematurity, septic shock, admission to IMV) and laboratory characteristics (elevated creatinine and thrombocytopenia) associated with higher mortality in patients with neonatal sepsis. Breastfeeding was a factor associated with survival in these patients.