Miracle-dz/UniFAR-FTUs huggingface dataset:
Variability of Fe II Emission Features in the Seyfert 1 Galaxy NGC 5548

We study the low-contrast Fe II emission blends in the ultraviolet (1250-2200 Å) and optical (4000-6000 Å) spectra of the Seyfert 1 galaxy NGC 5548 and show that these features vary in flux and that these variations are correlated with those of the optical continuum. The amplitude of variability of the optical Fe II emission is 50%-75% that of Hβ, and the ultraviolet Fe II emission varies with an even larger amplitude than Hβ. However, accurate measurement of the flux in these blends proves to be very difficult even using excellent Fe II templates to fit the spectra. We are able to constrain only weakly the optical Fe II emission-line response timescale to a value of less than several weeks; this upper limit exceeds all the reliably measured emission-line lags in this source so it is not particularly meaningful. Nevertheless, the fact that the optical Fe II and continuum flux variations are correlated indicates that line fluorescence in a photoionized plasma, rather than collisional excitation, is responsible for the Fe II emission. The iron emission templates are available upon request.
Angular Correlations of Galaxy Distribution

We study the angular correlations of various galaxy catalogs (the CfA1, SSRS1, Perseus-Pisces, APM Bright Galaxies, and Zwicky catalogs). We find that the angular correlation exponent is γa = 0.1 ± 0.1 rather than γa = 0.7, as usually found by the standard correlation function ω(θ). We identify the problem in the artificial decay of ω(θ). Moreover, we find that no characteristic angular scale is present in any of the analyzed catalogs. Finally, we show that all the available data are consistent with each other, and the angular distribution of galaxies is quite naturally compatible with a fractal structure with D ≈ 2.
Chemistry and Star Formation in the Host Galaxies of Type Ia Supernovae

We study the effect of environment on the properties of Type Ia supernovae by analyzing the integrated spectra of 57 local Type Ia supernova host galaxies. We deduce from the spectra the metallicity, current star formation rate, and star formation history of the host and compare these to the supernova decline rates. Additionally, we compare the host properties to the difference between the derived supernova distance and the distance determined from the best-fit Hubble law. From this we investigate possible uncorrected systematic effects inherent in the calibration of Type Ia supernova luminosities using light-curve fitting techniques. Our results indicate a statistically insignificant correlation in the direction of higher metallicity spiral galaxies hosting fainter Type Ia supernovae. However, we present qualitative evidence suggesting that progenitor age is more likely to be the source of variability in supernova peak luminosities than is metallicity. We do not find a correlation between the supernova decline rate and host galaxy absolute B magnitude, nor do we find evidence of a significant relationship between decline rate and current host galaxy star formation rate. A tenuous correlation is observed between the supernova Hubble residuals and host galaxy metallicities. Further host galaxy observations will be needed to refine the significance of this result. Finally, we characterize the environmental property distributions for Type Ia supernova host galaxies through a comparison with two larger, more general galaxy distributions using Kolmogorov-Smirnov tests. The results show the host galaxy metallicity distribution to be similar to the metallicity distributions of the galaxies of the NFGS and SDSS. Significant differences are observed between the SN Ia distributions of absolute B magnitude and star formation histories and the corresponding distributions of galaxies in the NFGS and SDSS. Among these is an abrupt upper limit observed in the distribution of star formation histories of the host galaxy sample, suggesting a Type Ia supernovae characteristic delay time lower limit of approximately 2.0 Gyr. Other distribution discrepancies are investigated and the effects on the supernova properties are discussed.
Histopathological characteristics of striped catfish (Pangasianodon hypophthalmus) in challenge with Edwardsiella ictaluri

The present study attempted to understand the histopathological index of striped catfish (Pangasianodon hypophthalmus) in challenge with Edwardsiella ictaluri, the causative agent of bacillary necrosis of Pangasius. Total of 355 healthy striped catfish juveniles was challenged with E. ictaluri (25 control; 330 infected). After the challenge, a total of 355 samples of the trunk kidney, liver, and spleen were collected at five different time points including just prior to infection, 24, 48, 264 and 312 hours post-infection (hpi) to measure the represented tissue damage of the fish. Results showed that many areas of the diseased liver, kidney, and fish organ tissues have been congested and hemorrhaged early at 24 hpi. The number of macrophage centers in the kidney and spleen increased at 24 - 48 hpi. Tissue damage (multifocal hemorrhages; necrosis) increased sharply from the period 48 - 256 hpi. The increased number of dead fish throughout infection, particularly the period from 48 to 200 hpi. At 312 hpi, the histopathological index was the highest, so the mortality rate was the highest during the experimental period.
A new twist on dS/CFT

We stress that the dS/CFT correspondence should be formulated using unitary principal series representations of the de Sitter isometry group/conformal group, rather than highest-weight representations as originally proposed. These representations, however, are inﬁnite-dimensional, and so do not account for the ﬁnite gravitational entropy of de Sitter space in a natural way. We then propose to replace the classical isometry group by a q -deformed version. This is carried out in detail for two-dimensional de Sitter and we ﬁnd that the unitary principal series representations deform to ﬁnite-dimensional unitary representations of the quantum group. We believe this provides a promising microscopic framework to account for the Bekenstein-Hawking entropy of de Sitter space.
Strings in flat space and pp waves from ${\cal N}=4$ Super Yang Mills

We explain how the string spectrum in flat space and pp-waves arises from the large $N$ limit, at fixed $g^2_{YM}$, of U(N) ${\cal N} =4$ super Yang Mills. We reproduce the spectrum by summing a subset of the planar Feynman diagrams. We give a heuristic argument for why we can neglect other diagrams. We also discuss some other aspects of pp-waves and we present a matrix model associated to the DLCQ description of the maximally supersymmetric eleven dimensional pp-waves.
Individual Differences and Paired Learning in Virtual Environments

 Abstract — In this research study, postsecondary students completed an information learning task in an avatar-based 3D virtual learning environment. Three factors were of interest in relation to learning; 1) the influence of collaborative vs. independent conditions, 2) the influence of the spatial arrangement of the virtual environment (linear, random and clustered), and 3) the relationship of individual differences such as spatial skill, general computer experience and video game experience to learning. Students completed pretest measures of prior computer experience and prior spatial skill. Following the premeasure administration, students were given instruction to move through the virtual environment and study all the material within 10 information stations. In the collaborative condition, students proceeded in randomly assigned pairs, while in the independent condition they proceeded alone. After this learning phase, all students individually completed a multiple choice test to determine information retention. The overall results indicated that students in pairs did not perform any better or worse than independent students. As far as individual differences, only spatial ability predicted the performance of students. General computer experience and video game experience did not. Taking a closer look at the pairs and spatial ability, comparisons were made on pairs high/matched spatial ability, pairs low/matched spatial ability and pairs that were mismatched on spatial ability. The results showed that both high/matched pairs and mismatched pairs outperformed low/matched pairs. That is, if a pair had even one individual with strong spatial ability they would perform better than pairs with only low spatial ability individuals. This suggests that, in virtual environments, the specific individuals that are paired together are important for performance outcomes. The paper also includes a discussion of trends within the data that have implications for virtual environment education.
Cosmological Results from High-z Supernovae

The High-z Supernova Search Team has discovered and observed eight new supernovae in the redshift interval z = 0.3-1.2. These independent observations, analyzed by similar but distinct methods, confirm the results of Riess and Perlmutter and coworkers that supernova luminosity distances imply an accelerating universe. More importantly, they extend the redshift range of consistently observed Type Ia supernovae (SNe Ia) to z ≈ 1, where the signature of cosmological effects has the opposite sign of some plausible systematic effects. Consequently, these measurements not only provide another quantitative confirmation of the importance of dark energy, but also constitute a powerful qualitative test for the cosmological origin of cosmic acceleration. We find a rate for SN Ia of (1.4 ± 0.5) × 10-4 h3 Mpc-3 yr-1 at a mean redshift of 0.5. We present distances and host extinctions for 230 SN Ia. These place the following constraints on cosmological quantities: if the equation of state parameter of the dark energy is w = -1, then H0t0 = 0.96 ± 0.04, and ΩΛ - 1.4ΩM = 0.35 ± 0.14. Including the constraint of a flat universe, we find ΩM = 0.28 ± 0.05, independent of any large-scale structure measurements. Adopting a prior based on the Two Degree Field (2dF) Redshift Survey constraint on ΩM and assuming a flat universe, we find that the equation of state parameter of the dark energy lies in the range -1.48 < w < -0.72 at 95% confidence. If we further assume that w > -1, we obtain w < -0.73 at 95% confidence. These constraints are similar in precision and in value to recent results reported using the WMAP satellite, also in combination with the 2dF Redshift Survey.
H2, C I, Metallicity, and Dust Depletion in the z = 2.34 Damped Lyα Absorption System toward QSO 1232+0815

We report the detection of strong molecular hydrogen (H2) absorption lines in the z = 2.34 damped Lyα absorber (DLA) toward QSO 1232+0815. This is the second detection in our survey for high-redshift molecules. The new ultraviolet spectrum of the QSO 1232+0815 at 0.9 Å resolution, taken with the Multiple Mirror Telescope Blue Channel Spectrograph, shows the υ = 0-0 up to 10-0 Lyman bands and also the Werner υ = 0-0 band of H2 associated with the z = 2.34 DLA. We have estimated the total H2 column density in this system. It ranges from ≈3 × 1019 cm-2 to ≈3 × 1017 cm-2 depending on the Doppler parameters, b = 6 or 10 km s-1. Based on the best fit with b = 6 km s-1, the estimated kinetic temperature is TK ≈ 80 K. The measurements of the abundance of zinc and iron in the same DLA show that the metallicity measured by the relatively undepleted element zinc is [Zn/H] = -0.86, while the relative abundance ratio [Fe/Zn] is -1.04, indicating dust depletion. Combining our work with previous results on H2 and relative heavy-element depletion, we find that there is a correlation between them, which suggests that the formation of H2 on dust grains is perhaps the dominant formation process in high-redshift DLAs. Detections of strong absorption from the ground and excited states of neutral carbon (C I) in the z = 2.34 DLA are also presented. The excitation temperature between the two fine-structure levels of C I is 15.7 ± 3.5 K, an upper limit for the cosmic microwave background radiation temperature at z = 2.34. This value is consistent with the prediction by the standard big bang cosmology.
Role of a triangle singularity in the $\pi \Delta$ decay of the $N(1700)(3/2^-)$

We show the important role played by the πΔ(1232) channel in the build up of the N(1700)(3/2−) resonance due to the nontrivial enhancement produced by a singularity of a triangular loop. The N(1700) is one of the dynamically generated resonances produced by the coupled-channel vector-baryon interaction. The πΔ channel was neglected in previous works but we show that it has to be incorporated into the coupled-channel formalism due to an enhancement produced by a singularity in the triangular loop with ρ, nucleon, and π as internal loop lines and π and Δ as external ones. The enhancement is of nonresonant origin but it contributes to the dynamical generation of the N(1700) resonance due to the nonlinear dynamics involved in the coupled-channel mechanisms. We obtain an important increase of the total width of the N(1700) resonance when the πΔ channel is included and provide predictions for the partial widths of the N(1700) decays into VB and πΔ.
Neutrino in magnetic fields: from the first studies to the new effects in neutrino oscillations

In this paper I should like to present {\bf {{the four new effects}}} in neutrino oscillations that have been recently investigated in my research group at the Department of Theoretical Physics of the Moscow State University. Due to the fact that these studies were stimulated by our previous research of neutrino interactions in the presence of magnetic fields, and also because the year 2004 commemorates the 40th years jubilee since the the first paper on the neutrino interaction in a magnetic field was published, a short review on the first papers dedicated to the problem of neutrinos in magnetic fields, and also on the recent results in this field, prefaces (Section 1) the discussion on {\bf the new effects} in neutrino oscillations. Section 2 is devoted to our recent studies of the electromagnetic properties of a {\it massive} neutrino, including the neutrino magnetic moment for different values of neutrino mass. In Section 3 we discuss {\it \bf the four new effects} in neutrino spin and flavour oscillations in different background environments.
Subwavelength atom localization via coherent population trapping

We present an atom localization scheme based on coherent population trapping. We consider atomic transitions in a Lambda configuration where the control field is a standing-wave field. The probe field and the control field produce coherence between the two ground states and prepare the atom in a pure state. We show that the population in one of the ground states has the same fringe pattern as produced by a Fabry–Perot interferometer and thus measurement of this population would localize the atom. Interestingly enough the role of the cavity finesse is played by the ratio of the intensities of the pump and probe. This is in fact the reason for obtaining extreme subwavelength localization.
The afterglow of GRB 021211: Another case of reverse shock emission

GRB 021211 was first detected by HETE II and its early afterglow has been observed. There is a break in its afterglow light curve at about 12 min after the bursts, before the break the optical flux decays with a power-law index of about -1.6, while at late time the power-law slope is about -1 (Chornock et al. 2002). Here we will show that the afterglow light curve of GRB 021211 can be explained within the framework of the standard fireball model. We show that the afterglow emission before the break time is the contribution of the emission from both the reverse shock and the forward shock, while the afterglow emission after the break time is mainly due to the forward shock emission. From the fitting we can give constraints on the parameters: the initial Lorentz factor 250less than or equal togamma(0)less than or equal to900, and the surrounding medium density ngreater than or equal to1.6x10(-3) atoms cm(-3). We propose that since the values of epsilon(B) and epsilon(e) are somewhat smaller for GRB 021211, so the peak energy of the reverse shock emission is well below the optical band, and thus it is substantially fainter than 990123 at similar epochs. Also we suggest that such a break might be a common feature in early optical afterglows.
The Meaning of the Wave Function: In Search of the Ontology of Quantum Mechanics

The meaning of the wave function has been a hot topic of debate since the early days of quantum mechanics. Recent years have witnessed a growing interest in this long-standing question. Is the wave function ontic, directly representing a state of reality, or epistemic, merely representing a state of (incomplete) knowledge, or something else? If the wave function is not ontic, then what, if any, is the underlying state of reality? If the wave function is indeed ontic, then exactly what physical state does it represent? In this book, I aim to make sense of the wave function in quantum mechanics and find the ontological content of the theory. The book can be divided into three parts. The first part addresses the question of the nature of the wave function (Chapters 1-5). After giving a comprehensive and critical review of the competing views of the wave function, I present a new argument for the ontic view in terms of protective measurements. In addition, I also analyze the origin of the wave function by deriving the free Schroedinger equation. The second part analyzes the ontological meaning of the wave function (Chapters 6, 7). I propose a new ontological interpretation of the wave function in terms of random discontinuous motion of particles, and give two main arguments supporting this interpretation. The third part investigates whether the suggested quantum ontology is complete in accounting for our definite experience and whether it needs to be revised in the relativistic domain (Chapters 8, 9).
B-mode auto-bispectrum due to matter bounce

Primordial Gravitational waves leave polarization imprints on the Cosmic Microwave Background (CMB) . In this article, we investigate polarization bispectrum, which is also referred to as the B-mode auto bispectrum, due to a matter bounce Universe. For simplicity, we consider a minimally coupled Einstein frame and obtain an analytical integral expression for the bispectrum and numerically perform the integration. We find that the signal-to-noise ratio is small, when compared with the same in the inflationary paradigm and hence quite difficult to detect in the future experiments. Thus a detection of tensor mode bispectrum in future will be helpful in ruling out matter bounce model. Also, to ease the numerical evaluation of the bispectrum, we develop and use various techniques. We believe that these techniques can be used in various other contexts.
Transient dynamics in interacting nanojunctions within self-consistent perturbation theory

We present an analysis of the transient electronic and transport properties of a nanojunction in the presence of electron–electron and electron–phonon interactions. We introduce a novel numerical approach which allows for an efficient evaluation of the non-equilibrium Green functions in the time domain. Within this approach we implement different self-consistent diagrammatic approximations in order to analyze the system evolution after a sudden connection to the leads and its convergence to the steady state. These approximations are tested by comparison with available numerically exact results, showing good agreement even for the case of large interaction strength. In addition to its methodological advantages, this approach allows us to study several issues of broad current interest like the build up in time of Kondo correlations and the presence or absence of bistability associated with electron–phonon interactions. We find that, in general, correlation effects tend to remove the possible appearance of charge bistability.
Strong three-meson couplings ofJ/ψandηc

We discuss the strong couplings $g_{PPV}$ and $g_{VVP}$ for vector ($V$) and pseudoscalar ($P$) mesons, at least one of which is a charmonium state $J/\psi$ or $\eta_c$. The strong couplings are obtained as residues at the poles of suitable form factors, calculated in a broad range of momentum transfers using a dispersion formulation of the relativistic constituent quark model. The form factors obtained in this approach satisfy all constraints known for these quantities in the heavy-quark limit. Our results suggest sizably higher values for the strong meson couplings than those reported in the literature from QCD sum rules.
Board Structure and Stock Market Liquidity: Evidence from Saudi's Banking Industry

This paper aims to explore the impact of corporate governance on banks’ stock market liquidity. Specifically, we examine the influence of one of the most important corporate governance mechanisms, board structure, on the stock market liquidity of listed banks in Saudi Arabia. We mainly concentrate on four characteristics of board structure: board size, board independence, board meetings and board busyness, and their impact on bid–ask spread, trading volume, turnover ratio and number of trades (employed as proxies of stock liquidity). This study employs a pooled ordinary least squares (OLS) model to investigate this relationship. Furthermore, we use a lag approach and the generalized method of moments (GMM) estimation to test for endogeneity issues. The findings of the two models are the same as the main estimation model of the OLS. Using a sample of 108 observations representing all banks listed on the Saudi Stock Market (TASI) from 2010 to 2020, we find a positive and significant association between board size and board independence with stock liquidity. However, board busyness is negatively associated with stock liquidity. Furthermore, we examine the relationship between board structure and agency problems. The results show that board size and board independence reduce agency problems, whereas board busyness increases agency problems. The findings of this paper provide implications for Saudi regulators, banks’ board of directors and banks’ shareholders.
A Gauge Field Theory for Continuous Spin Tachyons

We present a gauge field theory for unitary infinite dimensional tachyonic representations of the Poincar\'e group. It was obtained by a dimensional reduction from the gauge field theory for continuous spin particles in a cotangent bundle over Minkowski space-time. We discuss its BRST formulation and compute the partition function. Some cubic vertices are also presented and their properties discussed. In the massless limit the gauge theory for continuous spin tachyons reduces to the gauge theory for continuous spin particles.
Excursion set peaks: the role of shear

Recent analytical work on the modelling of dark halo abundances and clustering has demonstrated the advantages of combining the excursion set approach with peaks theory. We extend these ideas and introduce a model of excursion set peaks that incorporates the role of initial tidal effects or shear in determining the gravitational collapse of dark haloes. The model -- in which the critical density threshold for collapse depends on the tidal influences acting on protohaloes -- is well motivated from ellipsoidal collapse arguments and is also simple enough to be analytically tractable. We show that the predictions of this model are in very good agreement with measurements of the halo mass function and traditional scale dependent halo bias in N-body simulations across a wide range of masses and redshift. The presence of shear in the collapse threshold means that halo bias is naturally predicted to be nonlocal, and that protohalo densities at fixed mass are naturally predicted to have Lognormal-like distributions. We present the first direct estimate of Lagrangian nonlocal bias in N-body simulations, finding broad agreement with the model prediction. Finally, the simplicity of the model (which has essentially a single free parameter) opens the door to building efficient and accurate non-universal fitting functions of halo abundances and bias for use in precision cosmology.