Miracle-dz/UniFAR-FTUs huggingface dataset:
Searching for Wolf-Rayet Stars in I Zw 18: the Origin of He II Emission

I Zw 18 is the most metal-poor star-forming galaxy known and is an ideal laboratory to probe stellar evolution theory at low metallicities. Using archival Hubble Space Telescope WFPC2 imaging and Faint Object Spectrograph spectroscopy, we were able to improve previous studies. We constructed a continuum-free He II λ4686 map, which was used to identify Wolf-Rayet (W-R) stars recently found by ground-based spectroscopy and to locate diffuse nebular emission. Most of the He II λ4686 emission is associated with the northwest stellar cluster clearly displaced from the surrounding shell-like [O III] and Hα emission. We found evidence for He II sources, compatible with five to nine WNL stars and/or compact nebular He II λ4686 emission, as well as residual diffuse emission. Only one of them is outside the northwest cluster. We have done an extensive comparison between our results and the recent ground-based data used by Izotov et al. and Legrand et al. to identify WN and WC stars in I Zw 18. The differences between the various data may be understood in terms of varying slit locations, continuum fits, and contamination by nebular lines. We have calculated evolutionary tracks for massive stars and synthesis models at the appropriate metallicity (Z ≈ 0.02 Z☉). These single-star models predict a mass limit MWR ≈ 90 M☉ for W-R stars to become WN and WC/WO. For an instantaneous burst model with a Salpeter initial mass function extending up to Mup ≈ 120-150 M☉, our model predictions are in reasonable agreement with the observed equivalent widths. Our model is also able to fully reproduce the observed equivalent widths of nebular He II λ4686 emission due to the presence of WC/WO stars. This quantitative agreement and the spatial correlation of nebular He II λ4686 with the stellar cluster and the position of W-R stars shown from the ground-based spectra further supports the hypothesis that W-R stars are responsible for nebular He II emission in extragalactic H II regions.
Feeding practices and micronutrient status of children aged 0–36 months in Thulamela Municipality, Limpopo province

Background Micronutrient deficiency continues to be a major public health problem affecting infants and young children under 5 years of age worldwide. Aim The study aims to investigate feeding practices and micronutrient status of children aged 0–36 months. Setting The study was conducted at government clinics located in Thulamela Municipality, which is one of the local municipalities in Vhembe District, Limpopo province. Methods A cross-sectional survey was conducted. A total of 250 mothers with children aged 0–36 months were enrolled. A structured questionnaire was used to interview the mothers. Biochemical measurements of children were assessed using standard procedures. Results Only 7.6% of children were exclusively breastfed for 6 months. Majority (87.5%) of the children were introduced to complementary foods before 6 months and 98.8% of the children had a low dietary diversity score of less than four, while 9.2% had a dietary diversity score of more than four. The prevalence of vitamin A deficiency, anaemia and iron deficiency was 21.7%, 53.6% and 13.1%, respectively. For mothers who initiated breastfeeding immediately after delivery, the odds of children having low ferritin were 0.11 times, as compared to children who were initiated breastfeeding a day after delivery (odds ratio = 0.11; 95% confidence interval = 0.015–0.812). Conclusion Most of the children were introduced to complementary foods earlier than 6 months of age. Infant feeding practices were associated with micronutrients status. Contribution The study contributes to the body of literature on feeding practices and the micronutrient status of children.
Systematic Design of Linear Feedback Amplifiers

This work adds a quantitative description of distortion to the structured design method of negative-feedback amplifiers. It constitutes a power-series representation of the feedback amplifier, which may include dynamic (memory) effects, where the design parameters appear explicitly. These results have been incorporated into the systematic design method. It now includes design steps for calculating the required number of amplifying stages, and the optimal bias current allocation. The power-series representation of negative-feedback amplifiers models several properties of active devices. The effects of collector-base current tracking (current drive), high-level injection of BJTs, and the presence of base resistance influences on the nonlinear distortion performance are described. Furthermore, mobility reduction, and channel length modulation of FETs are modeled. Moreover, the power-series representation also allows the mismatch of balanced stages to be considered. This power-series representation explicitly states the conditions for achieving the desired nonlinear distortion performance of negative-feedback amplifiers. One of the main findings is that the current/voltage gain of an amplifying stage is more important than its intrinsic nonlinearity in this regard. The intrinsic nonlinearity of an amplifying stage is represented by nonlinearity coefficients. The coefficients are, in general, of the same order of magnitude for all technologies and configurations. Therefore, the ability of amplifying stages to contribute to the loop gain is more important. What is more, in contrast to common belief, applying local feedback does not improve the nonlinear distortion performance of negative-feedback amplifiers. The linearity loss can be slight, assuming that local feedback is applied to the amplifying stage that dominates the linearity performance. The least harmful place for local feedback is, therefore, often the output stage. (Less)
Income Insecurity and Mental Health in Pandemic Times

This paper provides novel evidence of the mental health effects of the Covid-19 outbreak. Between April 2020 and April 2022, we run four waves of a large representative survey in Spain, which we benchmark against a decade of prepandemic data. We document a large and sudden deterioration of mental health at the beginning of the pandemic, as the share of people reporting being depressed increased from 16% before the pandemic to 46% in April 2020. This effect is persistent over time, which translates into important and irreversible consequences, such as a surge in suicides. The effect is more pronounced for women, younger individuals and those with unstable incomes. Finally, using mediation analysis, event studies and machine learning techniques, we document the role of the labor market as an important driver of these effects, as women and the young are more exposed to unstable income sources. JEL Codes: I1, I14, H2, H12, E24
Critical dynamics and effective exponents of magnets with extended impurities

We investigate the asymptotic and effective static and dynamic critical behavior of (d=3)-dimensional magnets with quenched extended defects, correlated in $\epsilon_d$ dimensions (which can be considered as the dimensionality of the defects) and randomly distributed in the remaining $d-\epsilon_d$ dimensions. The field-theoretical renormalization group perturbative expansions being evaluated naively do not allow for the reliable numerical data. We apply the Chisholm-Borel resummation technique to restore convergence of the two-loop expansions and report the numerical values of the asymptotic critical exponents for the model A dynamics. We discuss different scenarios for static and dynamic effective critical behavior and give values for corresponding non-universal exponents.
Ab initio linear response and frozen phonons for the relaxor Pb Mg 1 ∕ 3 Nb 2 ∕ 3 O 3

We report first principles density functional studies using plane wave basis sets and pseudopotentials and all-electron linear augmented plane wave (LAPW) of the relative stability of various ferroelectric and antiferroelectric supercells of PMN $(\mathrm{Pb}{\mathrm{Mg}}_{1∕3}{\mathrm{Nb}}_{2∕3}{\mathrm{O}}_{3})$ for 1:2 chemical ordering along [111] and [001]. We used linear response with density functional perturbation theory as implemented in the code ABINIT to compute the Born effective charges, electronic dielectric tensors, long wavelength phonon frequencies and longitudinal optic-transverse optic (LO-TO) splittings. The polar response is different for supercells ordered along [111] and [001]. Several polar phonon modes show significant coupling with the macroscopic electric field giving giant LO-TO splittings. For [111] ordering, a polar transverse optic mode with $E$ symmetry is found to be unstable in the ferroelectric $P3m1$ structure and the ground state is found to be monoclinic. Multiple phonon instabilities of polar modes and their mode couplings provide the pathway for polarization rotation. The Born effective charges in PMN are highly anisotropic and this anisotropy contributes to the observed huge electromechanical coupling in PMN solid solutions.
W-ALGEBRAS FROM HEISENBERG CATEGORIES

The trace (or zeroth Hochschild homology) of Khovanov’s Heisenberg category is identified with a quotient of the algebra $W_{1+\infty }$ . This induces an action of $W_{1+\infty }$ on the center of the categorified Fock space representation, which can be identified with the action of $W_{1+\infty }$ on symmetric functions.
Dating App Facilitated Sexual Assault: A Retrospective Review of Sexual Assault Medical Forensic Examination Charts

Dating app facilitated sexual assault (DAppSA) is a concerning phenomenon with minimal published research. This retrospective study explored if DAppSAs were different than other sexual assaults (SAs) committed by acquaintances through a review of 3,413 sexual assault medical forensic examination (SAMFE) charts from 2017 to 2020 in a Mountain West state in the United States. Routine Activities Theory and Confluence Model of sexual aggression provided the theoretical framework for the study. Inclusion criteria for DAppSA cases included (1) victim was 14 years of age or older; (2) victim indicated meeting the perpetrator on a dating app; (3) SA occurred at initial in-person meeting; and (4) victim had a SAMFE with SA kit evidence collection. DAppSAs (n = 274) represented 8.02% of overall cases and 13.92% of acquaintance SAs (n = 1,968). DAppSA victims had unique characteristics including a higher percentage of male victims (7.5%), college students (22.2%), and victims with self-reported mental illness (MI) (59.6%). Victims were less likely to fight back during the assault with lower percentages of kicking (5.8%) and hitting (9%). DAppSA victims and perpetrators were less likely to use drugs or alcohol before or during the assault. DAppSAs were found to be more violent SAs with increased strangulation (32.4%); assaultive/penetrative acts; and victim injuries, especially anogenital and breast injuries. Unique and troubling differences were found in DAppSA cases than other SAs committed by acquaintances. Due to the increased violent nature of DAppSAs, the researchers propose that sexual predators use dating apps as hunting grounds for vulnerable victims. Recommendations to address dating app safety concerns, influence dating app usage policies, and improve care to survivors are discussed through systems-based and trauma-informed approaches.
Deflections of UHECRs in the Galactic magnetic field

We report results of the first comprehensive, high resolution study of the deflections of UHECRs using a realistic model of the Galactic magnetic field and extending to sufficiently low rigidities, R ≡ E/Z ⩾ 1018V, to describe Fe in the UHE energy range above ∼55 EeV, or the mixed composition reported by the Pierre Auger Collaboration at the energy of the observed dipole anisotropy. We use the Jansson-Farrar (JF12) model, which has both a large scale coherent and a structured random component, and determine deflections for fifteen rigidities from 1018.0 to 1020.0 V, for two different coherence length choices for the random component, Lcoh = 30 pc and 100 pc. We also check the sensitivity of UHECR deflections to the particular realization of the random field, for 3 rigidity values. For each rigidity and field model studied, the UHECR arrival direction distribution is determined for an arbitrary source direction, by inverting the trajectories of > 5×107 isotropically-distributed anti-CRs of the given rigidity, which we backtrack using the code CRT. We present skyplots and tables characterizing the arrival directions, for representative 1o sources. Except at high rigidity, the pattern of multiple images is very complex and depends strongly on the coherence length and source direction. For almost all sources, average deflections grow rapidly as the rigidity falls below 10 EV and deflections commonly are greater than 90̂. Magnification and demagnification can be strong at almost all rigidities, and varies significantly with source direction. Much of the extragalactic celestial sphere, behind and south of the Galactic Center, cannot be seen in UHECRs below 10 EV. One empirical regularity is that the average deflection of UHECRs from a given source, while growing with decreasing rigidity and depending on source direction and Lcoh, is about twice as large as the RMS angular spread about the mean arrival direction (centroid), independently of source direction, rigidity or Lcoh, albeit with outliers. The pattern of deflections obtained with the coherent field alone can be significantly different than with the complete field model, even as regards the position of the centroid, for some source directions and rigidities. Multiple images, sometimes very widely separated, are common for small coherence length, especially for low rigidity.
Can dark energy evolve to the Phantom

Dark energy with the equation of state $w(z)$ rapidly evolving from the dustlike ($w\ensuremath{\simeq}0$ at $z\ensuremath{\sim}1$) to the phantomlike ($\ensuremath{-}1.2\ensuremath{\lesssim}w\ensuremath{\lesssim}\ensuremath{-}1$ at $z\ensuremath{\simeq}0$) has been recently proposed as the best fit for the supernovae Ia data. Assuming that a dark energy component with an arbitrary scalar-field Lagrangian $p(\ensuremath{\varphi},{\ensuremath{\nabla}}_{\ensuremath{\mu}}\ensuremath{\varphi})$ dominates in the flat Friedmann universe, we analyze the possibility of a dynamical transition from the states $(\ensuremath{\varphi},\stackrel{\ifmmode \dot{}\else \textperiodcentered \fi{}}{\ensuremath{\varphi}})$ with $w\ensuremath{\ge}\ensuremath{-}1$ to those with $wl\ensuremath{-}1$ or vice versa. We have found that generally such transitions are physically implausible because they are either realized by a discrete set of trajectories in the phase space or are unstable with respect to the cosmological perturbations. This conclusion is confirmed by a comparison of the analytic results with numerical solutions obtained for simple models. Without the assumption of the dark energy domination, this result still holds for a certain class of dark energy Lagrangians, in particular, for Lagrangians quadratic in ${\ensuremath{\nabla}}_{\ensuremath{\mu}}\ensuremath{\varphi}$. The result is insensitive to topology of the Friedmann universe as well.
Communication in interfaith and multiethnic-racial families: Navigating identity and difference in family relationships

The current manuscript provides a critical review of family communication in multiethnic-racial and interfaith families. The review specifically focuses on differences related to religious and ethnic-racial identity, given that both are salient aspects of self-concept tied to psychosocial well-being, exist in a sociocultural environment characterized by racialized structures and systems of privilege, have been problematized through a deficit approach, and have implications for how to constructively address religious and ethnic-racial differences outside of the family. We begin by defining the three core concepts: (a) interfaith, (b) multiethnic-racial, and (c) family. We then discuss our methodology for selecting and reviewing empirical research and provide a synthesis of findings for each family type. We specifically address how interfaith then multiethnic-racial families communicate to address socialization and identity development, integrate differences, and combat bias. We conclude with a critical summary, arguing that interfaith and multiethnic-racial families are more accurately characterized through their strengths rather than difficulties. We point to limitations of current work, namely that research is largely based on Western perspectives on race/ethnicity and Ibrahimic religious traditions, that children and adolescent perspectives are relatively absent, and that the research tends to primarily focus on communication between couples or in parent-child relationships rather than extended family networks. Trajectories for future research include a focus on the manner in which communication surrounding identity and difference impacts self-concept and psychosocial well-being as well as contextualizing experiences of multiethnic-racial and interfaith families within the sociocultural environment. Our articulated conceptual landscape and synthesis of the research shed light on these complex relationships and encourage ongoing scholarship on these relatively understudied family forms.
MALS–NOT: Identifying Radio-bright Quasars for the MeerKAT Absorption Line Survey

We present a preparatory spectroscopic survey to identify radio-bright, high-redshift quasars for the MeerKAT Absorption Line Survey. The candidates have been selected on the basis of a single flux density limit at 1.4 GHz (>200 mJy), together with mid-infrared color criteria from the Wide-field Infrared Survey Explorer. Through spectroscopic observations using the Nordic Optical Telescope, we identify 72 quasars out of 99 candidates targeted. We measure the spectroscopic redshifts based on characteristic, broad emission lines present in the spectra. Of these 72 quasars, 64 and 48 objects are at sufficiently high redshift (z > 0.6 and z > 1.4) to be used for the L-band and UHF-band spectroscopic follow-up with the Square Kilometre Array precursor in South Africa: the MeerKAT.
A new collective mode in YBCO observed by time-domain reflectometry

We report the observation of coherent oscillations associated with charge density wave (CDW) order in the underdoped cuprate superconductor YBa2Cu3O6+x by time-resolved optical reflectivity. Oscillations with frequency 1.87 THz onset at approximately 105 K and 130 K for dopings of x = 0.67 (ortho-VIII) and x = 0.75 (ortho-III), respectively. Upon cooling below the superconducting critical temperature (T_c), the oscillation amplitude is enhanced, the phase shifts by \pi, and the frequency softens by \delta \nu / \nu~7%. A bi-quadratically coupled Landau-Ginzburg model qualitatively describes this behavior as arising from competition between superconducting and CDW orders.
Finite temperature induced fermion number in the nonlinear σ model in 2+1 dimensions

We compute the finite temperature induced fermion number for fermions coupled to a static nonlinear sigma model background in (2+1) dimensions, in the derivative expansion limit. While the zero temperature induced fermion number is well known to be topological (it is the winding number of the background), at finite temperature there is a temperature dependent correction that is nontopological -- this finite T correction is sensitive to the detailed shape of the background. At low temperature we resum the derivative expansion to all orders, and we consider explicit forms of the background as a CP^1 instanton or as a baby skyrmion.
Factors affecting satisfaction and intention to repurchase retail banking services in Vietnam

Abstract Retail banking services of Vietnamese commercial banks are developing along with economic growth, improving the repurchase behavior of customers helps banks maintain a competitive edge in the market. Therefore, the research was conducted on factors affecting satisfaction and intention to repurchase retail banking (RB) services. This study builds and validates the Structured Equation Model (SEM) to assess the causal effect of factors such as service quality, brand reputation and customer trust on customer satisfaction and repurchase intention RB services of commercial banks in Vietnam. Survey results of 605 customers have shown that 6 factors affect positively the intention of individual customers to repurchase banking services. In the transition from satisfaction to intention to repurchase the services, there are two moderating variables included in the study, which are switching costs and commitment from the relationship. The research results can be suggestions to help customers improve their intention to use the services again at Vietnamese commercial banks.
Hubble Space Telescope Emission-line Images of Nearby 3CR Radio Galaxies: Two Photoionization, Accretion, and Feedback Modes

We present HST/ACS narrowband images of a low-z sample of 19 3C radio galaxies to study the Hα and [O iii] emissions from the narrow-line region. Based on nuclear emission-line ratios, we divide the sample into high- and low-excitation galaxies (HEGs and LEGs). We observe different line morphologies, extended [O iii] emission, large [O iii]/Hα scatter across the galaxies, and a radio-line alignment. In general, HEGs show more prominent emission-line properties than LEGs: larger, more disturbed, more luminous, and more massive regions of ionized gas with slightly larger covering factors. We find evidence of correlations between line luminosities and (radio and X-ray) nuclear luminosities. All of these results point to a main common origin, the active nucleus, which ionizes the surrounding gas. However, the contribution of additional photoionization mechanisms (jet shocks and star formation) is needed to account for the different line properties of the two classes. A relationship between the accretion, photoionization, and feedback modes emerges from this study. For LEGs (hot-gas accretors), the synchrotron emission from the jet represents the main source of ionizing photons. The lack of cold gas and star formation in their hosts accounts for the moderate ionized-gas masses and sizes. For HEGs (cold-gas accretors), an ionizing continuum from a standard disk and shocks from the powerful jets are the main sources of photoionization, with a contribution from star formation. These components, combined with the large reservoir of cold/dust gas brought from a recent merger, account for the properties of their extended emission-line regions.
Rational Interpolation Methods for Symmetric Sylvester Equations

We discuss low-rank approximation methods for large-scale symmetric Sylvester equations. Follow- ing similar discussions for the Lyapunov case, we introduce an energy norm by the symmetric Sylvester operator. Given a rank nr, we derive necessary conditions for an approximation being optimal with respect to this norm. We show that the norm minimization problem is related to an objective function based on the H2-inner product for sym- metric state space systems. This objective function leads to first-order optimality conditions that are equivalent to the ones for the norm minimization problem. We further propose an iterative procedure and demonstrate its efficiency by means of some numerical examples.
Are High-Redshift Quasars Blurry?

It has been suggested that the fuzzy nature of spacetime at the Planck scale may cause light waves to lose phase coherence, and if severe enough this could blur images of distant pointlike sources sufficiently that they do not form an Airy pattern at the focal plane of a telescope. Blurring this dramatic has already been observationally ruled out by images from Hubble Space Telescope (HST), but I show that the underlying phenomenon could still be stronger than previously considered. It is harder to detect, which may explain why it has gone unseen. A systematic search is made in archival HST images of among the quasars with the highest known redshifts . Planck-scale-induced blurring may be evident, but this could be confused with partially resolved sources.