Miracle-dz/UniFAR-FTUs huggingface dataset:
On the α-element gradients of the Galactic thin disk using Cepheids

We present new homogeneous measurements of Na, Al, and three α-elements (Mg, Si, Ca) for 75 Galactic Cepheids. The abundances are based on high spectral resolution (R~ 38 000) and high signal-to-noise ratio (S/N ~ 50−300) spectra collected with UVES at ESO VLT. The current measurements were complemented with Cepheid abundances provided by our group (75) or available in the literature, for a total of 439 Galactic Cepheids. Special attention was given to providing a homogeneous abundance scale for these five elements plus iron. In addition, accurate Galactocentric distances (RG) based on near-infrared photometry are also available for all the Cepheids in the sample. They cover a large section of the Galactic thin disk (4.1 ≤RG≤ 18.4 kpc). We found that these five elements display well-defined linear radial gradients and modest standard deviations over the entire range of RG. Moreover, the [element/Fe] abundance ratios are constant across the entire thin disk; only the Ca radial distribution shows marginal evidence of a positive slope. These results indicate that the chemical enrichment history of iron and of the quoted five elements has been quite similar across the four quadrants of the Galactic thin disk. The [element/Fe] ratios are also constant over the entire period range. This empirical evidence indicates that the chemical enrichment of Galactic Cepheids has also been very homogenous within the range in age that they cover (~10−300 Myr). Once again, [Ca/Fe] vs. log P shows a (negative) gradient, since it is underabundant among the youngest Cepheids. Finally, we also find that Cepheid abundances agree quite well with similar abundances for thin and thick disk dwarf stars, and they follow the typical Mg−Al and Na−O correlations.
X-ray imaging of 30 year old wine grape wood reveals cumulative impacts of rootstocks on scion secondary growth and Ravaz index

Summary Annual rings from 30 year old vines in a California rootstock trial were measured to determine the effects of 15 different rootstocks on Chardonnay and Cabernet Sauvignon scions. Viticultural traits measuring vegetative growth, yield, berry quality, and nutrient uptake were collected at the beginning (1995 to 1999) and end (2017 to 2020) of the lifetime of a vineyard initially planted in 1991 and removed in 2021. X-ray Computed Tomography (CT) was used to measure ring widths in 103 vines. Ring width was modeled as a function of ring number using a negative exponential model. Early and late wood ring widths, cambium width, and scion trunk radius were correlated with 27 traits. Modeling of annual ring width shows that scions alter the width of the first rings but that rootstocks alter the decay of later rings, consistently shortening ring width throughout the lifetime of the vine. Ravaz index, juice pH, photosynthetic assimilation and transpiration rates, and instantaneous water use efficiency are correlated with scion trunk radius. Ultimately, our research indicates that rootstocks modulate secondary growth over years, altering physiology and agronomic traits. Rootstocks act in similar but distinct ways from climate to modulate ring width, which borrowing techniques from dendrochronology, can be used to monitor both genetic and environmental effects in woody perennial crop species.
Quantum Mechanics as Classical Physics

Here I explore a novel no-collapse interpretation of quantum mechanics that combines aspects of two familiar and well-developed alternatives, Bohmian mechanics and the many-worlds interpretation. Despite reproducing the empirical predictions of quantum mechanics, the theory looks surprisingly classical. All there is at the fundamental level are particles interacting via Newtonian forces. There is no wave function. However, there are many worlds.
Modeling taxi professional attitudes towards regulatory change and electromobility: evidence from Athens, Greece

ABSTRACT Worldwide, taxis hold a prominent position in urban mobility, as they offer comfortable and convenient transportation services. Recent technological developments create both new opportunities and limitations in the taxi industry and therefore regulatory reforms are required for the taxi market to properly adjust to and benefit from technological innovations, with fleet electrification currently in the spotlight. This paper investigates the attitude of taxi professionals with respect to embracing fleet electrification and accepting necessary regulatory reforms for that purpose. Data was obtained from a questionnaire survey among taxi professionals in Athens, Greece, and logistic regression models are exploited to analyze the factors affecting taxi market opinions on those two topics. Study outcomes can be proven useful in the sense that through profiling taxi professionals who are willing to adopt technological and regulatory reforms, incentive policies could be more targeted and economically efficient.
Statistical model of exotic rotational correlations in emergent space-time

A Lorentz invariant statistical model is presented for rotational fluctuations in the local inertial frame that arise from new quantum degrees of freedom of space-time. The model assumes invariant classical causal structure, and a Planck information density in invariant proper time determined by the world line of an observer. It describes macroscopic spacelike correlations that appear as observable timelike correlations in phase differences of light propagating on paths that begin and end on the same world line. The model allows an exact prediction for the autocorrelation of any interferometer time signal from the shape of the light paths. Specific examples computed for configurations that approximate realistic experiments show that the model can be rigorously tested, allowing a direct experimental probe of Planck scale degrees of freedom.
Deformed Lorentz symmetry and relative locality in a curved/expanding spacetime

The interest of part of the quantum-gravity community in the possibility of Planck-scale-deformed Lorentz symmetry is also fueled by the opportunities for testing the relevant scenarios with analyses, from a signal-propagation perspective, of observations of bursts of particles from cosmological distances. In this respect the fact that so far the implications of deformed Lorentz symmetry have been investigated only for flat (Minkowskian) spacetimes represents a very significant limitation, since for propagation over cosmological distances the curvature/expansion of spacetime is evidently tangible. We here provide a significant step toward filling this gap by exhibiting an explicit example of Planck-scale-deformed relativistic symmetries of a spacetime with constant rate of expansion (deSitterian). Technically we obtain the first ever example of a relativistic theory of worldlines of particles with 3 nontrivial relativistic invariants: a large speed scale ("speed-of-light scale"), a large distance scale (inverse of the "expansion-rate scale"), and a large momentum scale ("Planck scale"). We address some of the challenges that had obstructed success for previous attempts by exploiting the recent understanding of the connection between deformed Lorentz symmetry and relativity of spacetime locality. We also offer a preliminary analysis of the differences between the scenario we here propose and the most studied scenario for broken (rather than deformed) Lorentz symmetry in expanding spacetimes.
Convergence Analysis of a Modified Forward-Backward Splitting Algorithm for Minimization and Application to Image Recovery

Many applications in applied sciences and engineering can be considered as the convex minimization problem with the sum of two functions. One of the most popular techniques to solve this problem is the forward-backward algorithm. In this work, we aim to present a new version of splitting algorithms by adapting with Tseng’s extragradient method and using the linesearch technique with inertial conditions. We obtain its convergence result under mild assumptions. Moreover, as applications, we provide numerical experiments to solve image recovery problem. We also compare our algorithm and demonstrate the efficiency to some known algorithms.
From travelling waves to mild chaos: a supercritical bifurcation cascade in pipe flow

Abstract We study numerically a succession of transitions in pipe Poiseuille flow that lead from simple travelling waves to waves with chaotic time-dependence. The waves at the origin of the bifurcation cascade are twofold azimuthally periodic, shift–reflect symmetric, and have a non-dimensional axial wavelength of $1. 927$ diameters. As the Reynolds number is increased, successive transitions result in a wide range of time-dependent solutions that include spiralling, modulated travelling, modulated spiralling, doubly modulated spiralling and mildly chaotic waves. Numerical evidence suggests that the latter spring from heteroclinic tangles of the stable and unstable invariant manifolds of two shift–reflect symmetric, modulated travelling waves. The chaotic set thus produced is confined to a limited range of Reynolds numbers, bounded by the occurrence of manifold tangencies. The subspace of discrete symmetry to which the states studied here belong makes many of the bifurcation and path-following investigations presented readily accessible. However, we expect that most of the phenomenology carries over to the full state space, thus suggesting a mechanism for the formation and break-up of invariant states that can give rise to chaotic dynamics.
A Fair SINR Performance Comparison of FBMC/OQAM and FBMC/QAM Multicarrier Communication Systems in the Discrete-Time Framework

In the last couple of decades, multicarrier modulations have witnessed a considerable interest in wireless communication networks due to their ability to fight against multipath fading and offer multiple access with flexible resource sharing. One of the well known multicarrier modulation systems is filter-bank multi-carrier with an offset quadrature amplitude modulation (FBMC/OQAM), which was proposed as a powerful solution during the standardization of 5G. In this paper, we derive a closed-form expression of the signal to interference plus noise ratio (SINR) for FBMC/OQAM systems in the discrete-time context, for arbitrary wide sense stationary uncorrelated scattering (WSSUS) channels as well as transmitter (Tx) and receiver (Rx) waveforms. We quantify the potential gains in SINR brought by FBMC/OQAM, which exclusively operates on critical lattice density, with respect to FBMC/QAM, which have the flexibility to operate on critical or non-critical lattice densities. For completeness, we compare the performance of FBMC/OQAM in the discrete-time context, sweeping the discrete space of waveforms supports, with that of FBMC/OQAM in the continuous-time context, using the Hermite functions, and show how they perform similarly. Simulation results prove that FBMC/OQAM optimization algorithm, performing with the ping-pong optimized pulse shaping (POPS) paradigm, converges rapidly to excellent SINR values, even with small supports durations, in discrete-time context, which is equivalent to a reduced number of Hermite functions, in the continuous-time context.
HFPK 334: AN UNUSUAL SUPERNOVA REMNANT IN THE SMALL MAGELLANIC CLOUD

We present new Australia Telescope Compact Array radio-continuum and XMM-Newton/Chandra X-ray Observatory observations of the unusual supernova remnant (SNR) HFPK 334 in the Small Magellanic Cloud (SMC). The remnant follows a shell-type morphology in the radio continuum and has a size of ∼20 pc at the SMC distance. The X-ray morphology is similar; however, we detect a prominent point source close to the center of the SNR exhibiting a spectrum with a best-fit power law with a photon index of Γ = 2.7 ± 0.5. This central point source is most likely a background object and cannot be directly associated with the remnant. The high temperature, nonequilibrium conditions in the diffuse region suggest that this gas has been recently shocked and points toward a younger SNR with an age of ≲ 1800 yr. With an average radio spectral index of α = −0.59 ± 0.09, we find that an equipartition magnetic field for the remnant is ∼90 μG, a value typical of younger SNRs in low-density environments. Also, we report the detection of scattered radio polarization across the remnant at 20 cm, with a peak fractional polarization level of 25% ± 5%.
THE BLACK HOLE MASS–GALAXY LUMINOSITY RELATIONSHIP FOR SLOAN DIGITAL SKY SURVEY QUASARS

We investigate the relationship between the mass of the central supermassive black hole, MBH, and the host galaxy luminosity, Lgal, in a sample of quasars from the Sloan Digital Sky Survey Data Release 7. We use composite quasar spectra binned by black hole mass and redshift to assess galaxy features that would otherwise be overwhelmed by noise in individual spectra. The black hole mass is calculated using the photoionization method, and the host galaxy luminosity is inferred from the depth of the Ca ii H+K features in the composite spectra. We evaluate the evolution in the MBH–Lgal relationship by examining the redshift dependence of Δ log MBH, the offset in MBH from the local MBH–Lgal relationship. There is little systematic trend in Δ log MBH out to z = 0.8. Using the width of the [O iii] emission line as a proxy for the stellar velocity dispersion, σ*, we find agreement of our derived host luminosities with the locally observed Faber–Jackson relation. This supports the utility of the width of the [O iii] line as a proxy for σ* in statistical studies.
Topologically slice knots of smooth concordance order two

The existence of topologically slice knots that are of infinite order in the knot concordance group followed from Freedman's work on topological surgery and Donaldson's gauge theoretic approach to 4-manifolds. Here, as an application of Ozsvath and Szabo's Heegaard-Floer theory, we show the existence of an infinite subgroup of the smooth concordance group generated by topologically slice knots of concordance order two. In addition, no nontrivial element in this subgroup can be represented by a knot with Alexander polynomial one.
Manipulation of single-photon states encoded in transverse spatial modes: possible and impossible tasks

Controlled generation and manipulation of photon states encoded in their spatial degrees of freedom is a crucial ingredient in many quantum-information tasks exploiting higher-than-two dimensional encoding. Here, we prove the impossibility to arbitrarily modify $d$-level state superpositions (qudits) for $dg2$, encoded in the transverse modes of light, with optical components associated to the group of symplectic transforms (Gaussian operations). Surprisingly, we also provide an explicit construction of how non-Gaussian operations acting on mode subspaces do enable one to overcome the limit $d=2$. In addition, this set of operations realizes the full SU(3) algebra.
Radiative decay and level shift on an atom in an optical resonator

This thesis describes a theoretical and experimental investigation of the intensities, linewidths, and frequencies of radiation by an atom in an optical resonator. It is found that the atom's spontaneous emission rate may be enhanced or inhibited, depending on the tuning of the resonator, and its transition frequencies shifted. A simple classical description of these effects is given in which the atom is modelled as a dipole oscillator whose radiated field is reflected back onto itself by the resonator's mirrors. A more rigorous and detailed quantum mechanical description is also given, and it is found that for the case of a weakly excited two-level atom, the quantum and classical calculations agree. Two separate experiments are carried out. In the first, an atomic beam of ytterbium passes between the mirrors of a confocal resonator and is excited by a single mode cw dye laser on the 1S0 P1 transition, and the intensity of radiation by the atoms into the cavity modes is recorded as a function of cavity tuning. The spontaneous emission rate of the atoms into the cavity modes is enhanced or inhibited by a factor of the order of the resonator's finesse when the resonator is tuned or detuned from the atomic resonance, respectively. This is the first observation of cavity-modified spontaneous emission by atoms in a resonator at visible wavelengths. The total spontaneous emission rate is modified by only about 2%, because the solid angle: subtended by the cavity mirrors is small. This change in total spontaneous emission rate is indirectly verified by a measurement of the intensity of fluorescence out the sides of the resonator. In the second experiment, barium atoms are excited near the center of a concentric optical resonator, and the center frequency and linewidth of the 1So P1 transition is studied as a function of resonator tuning. Shifts in the transition center frequency, due to radiative level shifts, and changes in linewidth, due to enhanced and suppressed spontaneous emission, are observed. The total spontaneous emission linewidth is increased by 20% and decreased by 8%. This is the first demonstration of both line narrowing and broadening and frequency shifts arising from vacuum radiative effects in a spectroscopic experiment. The experimental conditions are very precise: two-level atoms are excited by a single cw dye laser, and competing decay channels and nonradiative effects are absent. Therefore a direct comparison between theory and experiment can be made, and it is found that good agreement is obtained. Thesis Supervisor: Michael S. Feld Title: Professor of Physics
POSSIBLE SIGNATURES OF EJECTA–COMPANION INTERACTION IN iPTF 13bvn

We investigate the possible effects of the supernova (SN) ejecta hitting the companion star in iPTF 13bvn, focusing on the observable features when it becomes visible. iPTF 13bvn is a type Ib SN that may become the first case in which its progenitor is identified as a binary (by observations in the near future). According to calculations by Bersten et al. the progenitor should have a mass ≈ 3.5 M ⊙ ? > to reproduce the SN light curve, and such compact stars can only be produced via binary evolution. This is one of the reasons that we expect the progenitor to be a binary, but this should be confirmed by observing the remaining companion after the SN. Bersten et al.’s evolutionary calculations suggest that the companion star will be an overluminous OB star at the moment of SN. With a combination of hydrodynamical and evolutionary simulations, we find that the secondary star will be heated by the SN ejecta and expand to have larger luminosities and lower surface effective temperatures. The star will look like a red supergiant and this should be taken into account when searching for the companion star in the SN ejecta in future observations.
On the dark matter profile in Sculptor: breaking the β degeneracy with Virial shape parameters

We present a new method for studying tracers in gravitational systems where higher moments of the line-of-sight velocity distribution are introduced via Virial equations rather than the Jeans equations. Unlike the fourth order Jeans equations, the fourth order Virial equations can simply be added to the standard second order Jeans equation without introducing a new anisotropy parameter $\beta^{\prime}$. We introduce two new global shape parameters $\zeta_A$ and $\zeta_B$ which replace the kurtosis as a more statistically robust measure of the shape of the line of sight velocity distribution. We show that in the case of stars in dwarf spheroidal galaxies these new parameters can significantly reduce the range of density profiles that are otherwise consistent with the observed stellar kinematics (a problem sometimes known as the $\beta$ degeneracy). Specifically, we find that $\zeta_A$ focuses tightly on a subset of solutions where cusped density profiles are degenerate with more concentrated cored dark matter halos. If the number density of stars $\nu(r)$ is fixed, then introducing $\zeta_B$ can further reduce the space of solutions by constraining the outer slope of the dark matter density profile. Assuming a Plummer profile for $\nu(r)$ we recover the surprising result that the dark matter in Sculptor may be cuspy after all, in contrast to the conclusions of other approaches.
Mediating Role of Cultural Identity in the Relationship between Social Media Use Intensity and Social Media Use Purpose among Chinese International Students in Malaysia

Social media has become essential for international students adjusting to a new environment. Previous research has shown that social media use purposes influence international students' cognition, psychology, and behavior. Limited studies have explored whether social media use purposes could be modified. This study investigated whether and how social media use intensity could influence use purpose by focusing on the mediating role of cultural identity among 213 Chinese international students studying in Malaysia. Data were analyzed using both SPSS and PROCESS macro. The findings revealed that social media use intensity positively predicted social media use purpose. Cultural identity (both Chinese and Malaysian cultural identity) partially mediated the relationship between social media use intensity and social media use purpose. Therefore, part of the impact of social media use intensity on social use purpose is achieved through cultural identity. By comparing the proportion of the mediating effect to the total effect, Malaysian cultural identity had a larger mediating effect than Chinese cultural identity. The results of this study could help improve the cross-cultural experience of Chinese students in Malaysia.
Enhanced current quantization in high-frequency electron pumps in a perpendicular magnetic field

We present experimental results of high-frequency quantized charge pumping through a quantum dot formed by the electric field arising from applied voltages in a GaAs/AlGaAs system in the presence of a perpendicular magnetic field B. Clear changes are observed in the quantized current plateaus as a function of applied magnetic field. We report on the robustness in the length of the quantized plateaus and improvements in the quantization as a result of the applied B field.
Josephson tunnel junctions with a strong ferromagnetic interlayer

The dependence of the critical current density ${j}_{c}$ on the ferromagnetic interlayer thickness ${d}_{F}$ was determined for $\text{Nb}/{\text{Al}}_{2}{\text{O}}_{3}/\text{Cu}/\text{Ni}/\text{Nb}$ Josephson tunnel junctions with ferromagnetic Ni interlayer thicknesses from very thin films $(\ensuremath{\sim}1\text{ }\text{nm})$ upward and classified into $F$-layer thickness regimes showing a dead magnetic layer, exchange, $\text{exchange}+\text{anisotropy}$ and total suppression of ${j}_{c}$. The Josephson coupling changes from 0 to $\ensuremath{\pi}$ as function of ${d}_{F}$, and\char22{}very close to the crossover thickness\char22{}as function of temperature. The strong suppression of the supercurrent in comparison to nonmagnetic $\text{Nb}/{\text{Al}}_{2}{\text{O}}_{3}/\text{Cu}/\text{Nb}$ junctions indicated that the insertion of a $F$ layer leads to additional interface scattering. The transport inside the dead magnetic layer was in dirty limit. For the magnetically active regime fitting with both the clean and the dirty limit theories was carried out, indicating dirty limit condition, too. The results were discussed in the framework of literature.