Miracle-dz/UniFAR-FTUs huggingface dataset:
Faint high-redshift AGN in the Chandra deep field south: the evolution of the AGN luminosity function and black hole demography

Context. We present detection and analysis of faint X-ray sources in the Chandra deep field south (CDFS) using the 4 Ms Chandra observation. Aims. We place constraints on active galactic nuclei (AGN) luminosity functions at z = 3–7, its cosmological evolution, and highredshift black hole and AGN demography. Methods. We use a new detection algorithm, using the entire three-dimensional data-cube (position and energy), and searching for X-ray counts at the position of high-z galaxies in the GOODS-South survey. Results. This optimized technique results in the identification of 54 AGN at z > 3, 29 of which are new detections. Applying stringent completeness criteria, we derive AGN luminosity functions in the redshift bins 3–4, 4–5, and >5.8 and for 42.75 3( 18 +17 −10 %). Their optical counterparts do not show any reddening and we thus conclude that the size of the X-ray absorber is likely smaller than the dust sublimation radius. We finally report the discovery of a highly star-forming galaxy at z = 3.47, arguing that its X-ray luminosity is likely dominated by stellar sources. If confirmed, this would be one of the farthest objects in which stellar sources have been detected in X-rays.
Congruence lattices forcing nilpotency

Given a lattice $\mathbb{L}$ and a class $K$ of algebraic structures, we say that $\mathbb{L}$ \emph{forces nilpotency} in $K$ if every algebra $\mathbf{A} \in K$ whose congruence lattice $\mathrm{Con} (\mathbf{A})$ is isomorphic to $\mathbb{L}$ is nilpotent. We describe congruence lattices that force nilpotency, supernilpotency or solvability for some classes of algebras. For this purpose, we investigate which commutator operations can exist on a given congruence lattice.
Dimension Reduction for the Landau-de Gennes Model: The Vanishing Nematic Correlation Length Limit

We study nematic liquid crystalline films within the framework of the Landau-de Gennes theory in the limit when both the thickness of the film and the nematic correlation length are vanishingly small compared to the lateral extent of the film. We prove $\Gamma$-convergence for a sequence of singularly perturbed functionals with a potential vanishing on a high-dimensional set and a Dirichlet condition imposed on admissible functions. This then allows us to prove the existence of local minimizers of the Landau-de Gennes energy in the spirit of a theorem due to Kohn and Sternberg despite the lack of compactness arising from the high-dimensional structure of the wells. The limiting energy consists of leading order perimeter terms, similar to Allen-Cahn models, and lower order terms arising from vortex structures reminiscent of Ginzburg-Landau models.
Chiral phase transition and Schwinger mechanism in a pure electric field

We systematically study the chiral symmetry breaking and restoration in the presence of a pure electric field in the Nambu--Jona-Lasinio (NJL) model at finite temperature and baryon chemical potential. In addition, we also study the effect of the chiral phase transition on the charged pair production due to the Schwinger mechanism. For these purposes, a general formalism for parallel electric and magnetic fields is developed at finite temperature and chemical potential for the first time. In the pure electric field limit $B\rightarrow0$, we compute the order parameter, the transverse-to-longitudinal ratio of the Goldstone mode velocities, and the Schwinger pair production rate as functions of the electric field. The inverse catalysis effect of the electric field to chiral symmetry breaking is recovered. And the Goldstone mode is find to disperse anisotropically such that the transverse velocity is always smaller than the longitudinal one, especially at nonzero temperature and baryon chemical potential. As expected, the quark-pair production rate is greatly enhanced by the chiral symmetry restoration.
Identifying Student Research Project Impact Using the Buxton and Hanney Payback Framework

Objectives. To determine whether evidence of the impact of student quality improvement projects and research projects on practice sites and the community can be identified using the Buxton and Hanney Payback Framework (BHPF). Methods. The BHPF was used to identify the broader impact of quality improvement projects and research projects conducted by the Doctor of Pharmacy (PharmD) class of 2020. The BHPF includes five domains of community impact: knowledge production, benefits to health or the health sector, benefits to future research, economic benefits, and policy and product development. Data were collected by having project preceptors complete a questionnaire and by reviewing student project posters. Data were analyzed by calculating frequencies and percentages for each domain. Results. Projects (N=73) were completed by 107 pharmacy students at health-system sites, community sites, academic sites, and other sites, and most often involved clinical care and pharmacy services (49%). Thirty-three preceptors (55%) responded to the questionnaire, and 73 project posters were reviewed. The most frequently identified impact types were knowledge production (n=43 for questionnaire, n=24 for posters) and health/health sector benefits (n=46 for questionnaire, n=8 for posters). Less frequently identified were economic benefits (total n=19), benefits to future research (total n=13), and policy and product development (total n=10). Conclusions. This study provides evidence that the impact of PharmD student quality improvement and research projects on practice sites and communities can be identified using the BHPF framework, and this impact extends beyond the usual academic outcomes of poster presentations and publications to include benefits related to improving quality of services, improving workflow, and providing opportunity for personal development.
Fertility numbers

A nonnegative integer is called a fertility number if it is equal to the number of preimages of a permutation under West's stack-sorting map. We prove structural results concerning permutations, allowing us to deduce information about the set of fertility numbers. In particular, the set of fertility numbers is closed under multiplication and contains every nonnegative integer that is not congruent to $3$ modulo $4$. We show that the lower asymptotic density of the set of fertility numbers is at least $1954/2565\approx 0.7618$. We also exhibit some positive integers that are not fertility numbers and conjecture that there are infinitely many such numbers.
An Analysis of Pre-Training on Object Detection

We provide a detailed analysis of convolutional neural networks which are pre-trained on the task of object detection. To this end, we train detectors on large datasets like OpenImagesV4, ImageNet Localization and COCO. We analyze how well their features generalize to tasks like image classification, semantic segmentation and object detection on small datasets like PASCAL-VOC, Caltech-256, SUN-397, Flowers-102 etc. Some important conclusions from our analysis are --- 1) Pre-training on large detection datasets is crucial for fine-tuning on small detection datasets, especially when precise localization is needed. For example, we obtain 81.1% mAP on the PASCAL-VOC dataset at 0.7 IoU after pre-training on OpenImagesV4, which is 7.6% better than the recently proposed DeformableConvNetsV2 which uses ImageNet pre-training. 2) Detection pre-training also benefits other localization tasks like semantic segmentation but adversely affects image classification. 3) Features for images (like avg. pooled Conv5) which are similar in the object detection feature space are likely to be similar in the image classification feature space but the converse is not true. 4) Visualization of features reveals that detection neurons have activations over an entire object, while activations for classification networks typically focus on parts. Therefore, detection networks are poor at classification when multiple instances are present in an image or when an instance only covers a small fraction of an image.
Short- and mid-term changes in CORVIS ST parameters in successful, adult orthokeratology patients

ABSTRACT Clinical relevance The changes in various biomechanical and tomographic characteristics of the cornea associated with orthokeratology may allow us to identify potential mid- and long-term structural alterations, resulting in a better understanding of the governing mechanisms of this procedure and in its optimisation. Background The study aimed at describing short and mid-term changes in CORVIS ST® parameters and indices in orthokeratology (ortho-k), and their diurnal variations. Methods A prospective observational study was designed in which several CORVIS ST® parameters of 75 new adult participants successfully fitted with overnight ortho-k Seefree® (Conóptica – Hecht Contactlinsen) contact lenses were explored. Measurements were conducted in baseline (BL) conditions and in the morning and evening at the one-night (1 NM/1NT), one-week (1WM/1 WT) and 3-month (3 MM/3MT) follow-up visits. Results Statistically significant differences were found in DARatio_2 mm, IntRad, ARTh, CBI and TBI following overnight ortho-k, when compared with BL values, with most values reaching stability at 1WM or reverting to BL values at 3 MM. The ARTh and CBI parameters showed some of the most significant temporal variations (both p < 0.001), probably reflecting the encountered differences in central corneal thickness between BL and 1WM (p = 0.010) and between BL and 3 MM (p = 0.016). In general, corneal rigidity was higher in the morning at all follow-up visits, and decreased during the day. No statistically significant changes in adjusted intraocular pressure values were found. Conclusion Ortho-k in adults may be considered a safe procedure in terms of short and mid-term changes in CORVIS ST® parameters. The observed alterations in most of the parameters provided by the Corvis ST® probably responded to the well-described changes in corneal pachymetry and tomography, rather than to actual alterations in corneal rigidity.
Molecular analysis of enteropathogenic Escherichia coli (EPEC) isolates from healthy food‐producing animals and humans with diarrhoea

Enteropathogenic Escherichia coli (EPEC) is a pathogen associated with acute diarrhoea in humans. To determine whether EPEC isolated from healthy food‐producing animals possesses the same virulence gene repertoire as EPEC isolated from human with diarrhoea, we compared six typical EPEC (tEPEC) and 20 atypical EPEC (aEPEC) from humans with diarrhoea and 42 aEPEC from healthy animals (swine, sheep and buffaloes), using pulsed‐field gel electrophoresis (PFGE), virulence markers, serotyping and subtyping of eae and tir genes. We found that human and animal isolates shared virulence genes, including nleB, nleE and nleF, which were associated with human diarrhoea. Serogroups and serotypes identified in isolates of food‐producing animals such as O26:H11, O128:H2, O76:H7, O103, O108, O111 and O145, have previously been implicated in human disease. The subtypes eae and tir were also shared between human and animal isolates, being eae‐γ1 and eae‐β1 the most prevalent in both groups, while the most common tir subtypes were α and β. Despite PFGE analysis demonstrating that EPEC strains are heterogeneous and there was no prevalent clone identified, EPEC isolated from humans and food‐producing animals shared some characteristics, such as virulence genes associated with human diarrhoea, indicating that food‐producing animals could play a role as reservoirs for those genes.
Ramanujan's $_1\psi_1$ summation theorem --- perspective, announcement of bilateral $q$-Dixon--Anderson and $q$-Selberg integral extensions, and context

The Ramanujan $_1\psi_1$ summation theorem in studied from the perspective of $q$-Jackson integrals, $q$-difference equations and connection formulas. This is an approach which has previously been shown to yield Bailey's very-well-poised $_6\psi_6$ summation. Bilateral Jackson integral generalizations of the Dixon--Anderson and Selberg integrals relating to the type $A$ root system are identified as natural candidates for multidimensional generalizations of the Ramanujan $_1\psi_1$ summation theorem. New results of this type are announced, and furthermore they are put into context by reviewing from previous literature explicit product formulas for Jackson integrals relating to other roots systems obtained from the same perspective.
Facing the wind of the pre-FUor V1331 Cyg ?

The mass outows in T Tauri stars (TTS) are thought to be an eective mechanism to remove angular momentum during the pre-main sequence contraction of a low mass star. The most powerful winds are observed at the FUor stage of stellar evolution. V1331 Cyg has been considered as a TTS at the pre-FUor stage. We analyze highresolution spectra of V1331 Cyg collected in 1998{2007 and 20-days series of spectra taken in 2012. For the rst time the photospheric spectrum of the star is detected and stellar parameters are derived: spectral type G7{K0 IV, mass 2.8 M , radius 5 R , v sini < 6 km s 1 . The photospheric spectrum is highly veiled, but the amount of veiling is not the same in dierent spectral lines, being lower in weak transitions and much higher in strong transitions. The Feii 5018, Mgi 5183, Ki 7699 and some other lines of metals are accompanied by a ‘shell’ absorption at radial velocity of about -240 km s 1 . We show that these absorptions form in the post-shock gas in the jet, i.e. the star is seen though its jet. The P Cyg proles of H and H indicate the terminal wind velocity of about 500 km s 1 , which vary on time-scales from several days to years. A model of the stellar wind is developed to interpret the observations. The model is based on calculation of hydrogen spectral lines using the radiative transfer code torus. The observed H and H line proles and their variability can be well reproduced with a stellar wind model, where the mass-loss rate and collimation (opening angle) of the wind are variable. The changes of the opening angle may be induced by small variability in magetization of the inner disc wind. The mass-loss rate is found to vary within (6 11) 10 8 M yr 1 , with the accretion rate of 2.0 10 6 M yr 1 .
Stable capillary hypersurfaces in a half-space or a slab

We study stable immersed capillary hypersurfaces in a domain $\mathcal B$ which is either a half-space or a slab in the Euclidean space $\Bbb R^{n+1}. $ We prove that such a hypersurface $\Sigma$ is rotationally symmetric in the following cases: (1) $n=2$, $\mathcal B$ is a slab and $\Sigma$ has genus zero, (2) $n\geq 2$, $\mathcal B$ is a slab, the angle of contact is $\pi/2$ and each component of $\partial\Sigma$ is embedded, (3) $n\geq 2,$ $\mathcal B$ is a half-space, the angle of contact is $<\pi/2$ and each component of $\partial\Sigma$ is embedded. Moreover, in case (2), if not a right circular cylinder, the hypersurface has to be graphical over a domain in $\partial\mathcal B. $ In case (3), the hypersurface is a spherical cap.
Inhomogeneity effects in cosmology

This paper looks at how inhomogeneous spacetime models may be significant for cosmology. First it addresses how the averaging process may affect large-scale dynamics, with backreaction effects leading to effective contributions to the averaged energy–momentum tensor. Second, it considers how local inhomogeneities may affect cosmological observations in cosmology, possibly significantly affecting the concordance model parameters. Third, it presents the possibility that the universe is spatially inhomogeneous on Hubble scales, with a violation of the Copernican principle leading to an apparent acceleration of the universe. This could perhaps even remove the need for the postulate of dark energy.
BULGELESS GIANT GALAXIES CHALLENGE OUR PICTURE OF GALAXY FORMATION BY HIERARCHICAL CLUSTERING,

To better understand the prevalence of bulgeless galaxies in the nearby field, we dissect giant Sc–Scd galaxies with Hubble Space Telescope (HST) photometry and Hobby–Eberly Telescope (HET) spectroscopy. We use the HET High Resolution Spectrograph (resolution R ≡ λ/FWHM ≃ 15, 000) to measure stellar velocity dispersions in the nuclear star clusters and (pseudo)bulges of the pure-disk galaxies M 33, M 101, NGC 3338, NGC 3810, NGC 6503, and NGC 6946. The dispersions range from 20 ± 1 km s−1 in the nucleus of M 33 to 78 ± 2 km s−1 in the pseudobulge of NGC 3338. We use HST archive images to measure the brightness profiles of the nuclei and (pseudo)bulges in M 101, NGC 6503, and NGC 6946 and hence to estimate their masses. The results imply small mass-to-light ratios consistent with young stellar populations. These observations lead to two conclusions. (1) Upper limits on the masses of any supermassive black holes are M• ≲ (2.6 ± 0.5) × 106 M☉ in M 101 and M• ≲ (2.0 ± 0.6) × 106 M☉ in NGC 6503. (2) We show that the above galaxies contain only tiny pseudobulges that make up ≲3% of the stellar mass. This provides the strongest constraints to date on the lack of classical bulges in the biggest pure-disk galaxies. We inventory the galaxies in a sphere of radius 8 Mpc centered on our Galaxy to see whether giant, pure-disk galaxies are common or rare. We find that at least 11 of 19 galaxies with Vcirc > 150 km s−1, including M 101, NGC 6946, IC 342, and our Galaxy, show no evidence for a classical bulge. Four may contain small classical bulges that contribute 5%–12% of the light of the galaxy. Only four of the 19 giant galaxies are ellipticals or have classical bulges that contribute ∼1/3 of the galaxy light. We conclude that pure-disk galaxies are far from rare. It is hard to understand how bulgeless galaxies could form as the quiescent tail of a distribution of merger histories. Recognition of pseudobulges makes the biggest problem with cold dark matter galaxy formation more acute: How can hierarchical clustering make so many giant, pure-disk galaxies with no evidence for merger-built bulges? Finally, we emphasize that this problem is a strong function of environment: the Virgo cluster is not a puzzle, because more than 2/3 of its stellar mass is in merger remnants.
High resolution optical spectroscopy of the N2-rich comet C/2016 R2 (PanSTARRS)

Context. Early observations of comet C/2016 R2 (PanSTARRS) have shown that the composition of this comet is very peculiar. Radio observations have revealed a CO-rich and HCN-poor comet and an optical coma dominated by strong emission bands of CO+ and, more surprisingly, N2+. Aims. The strong detection of N2+ in the coma of C/2016 R2 provided an ideal opportunity to measure the 14N∕15N isotopic ratio directly from N2+ for the first time, and to estimate the N2∕CO ratio, which is an important diagnostic to constrain formation models of planetesimals, in addition to the more general study of coma composition. Methods. We obtained high resolution spectra of the comet in February 2018 when it was at 2.8 au from the Sun. We used the UVES spectrograph of the European Southern Observatory Very Large Telescope, complemented with narrowband images obtained with the TRAPPIST telescopes. Results. We detect strong emissions from the N2+ and CO+ ions, but also CO2+, emission lines from the CH radical, and much fainter emissions of the CN, C2, and C3 radicals that were not detected in previous observations of this comet. We do not detect OH or H2O+, and we derive an upper limit of the H2O+∕CO+ ratio of 0.4, implying that the comet has a low water abundance. We measure a N2+/CO+ ratio of 0.06 ± 0.01. The non-detection of NH2 indicates that most of the nitrogen content of the comet is in N2. Together with the high N2+/CO+ ratio, this could indicate a low formation temperature of the comet or that the comet is a fragment of a large differentiated Kuiper Belt object. The CO2+/CO+ ratio is 1.1 ± 0.3. We do not detect 14N15N+ lines and can only put a lower limit on the 14N∕15N ratio (measured from N2+) of about 100, which is compatible with measurements of the same isotopic ratio for NH2 and CN in other comets. Finally, in addition to the [OI] and [CI] forbidden lines, we detect for the first time the forbidden nitrogen lines [NI] doublet at 519.79 and 520.03 nm in the coma of a comet.
Modelling the broad-band spectra of MCG-6-30-15 with a relativistic reflection model

The spectrum of the bright Seyfert I galaxy MCG-6-30-15 shows a broad Fe Kα emission line, generally interpreted to originate very close to the central black hole which must then have a high spin. The observed X-ray variability is driven by a power-law component, with little variability found in the iron line energy band. The disconnection of continuum and line variability may be a consequence of strong gravitational light bending. The X-ray spectrum of MCG-6-30-15 is however complex, strongly modified at soft X-ray energies by warm absorbers, which some workers have extended to build an absorption-dominated model of the whole source behaviour. The absorption model interprets the whole X-ray spectrum without a relativistic reflection component and attributes most variability to the warm absorbers. We re-examine the XMM–Newton, Chandra and Suzaku data taken in 2001, 2004 and 2006, respectively, and construct a model consisting of several warm absorbers confirmed by spectral analysis, together with a relativistically blurred reflection component that explains both the soft and hard excesses as well. The model works well on data from all epochs, demonstrating that the reflection model provides a consistent interpretation of the broad-band spectrum of MCG-6-30-15.
XMM-NEWTON DETECTS A HOT GASEOUS HALO IN THE FASTEST ROTATING SPIRAL GALAXY UGC 12591

We present our XMM-Newton observation of the fastest rotating spiral galaxy UGC 12591. We detect hot gas halo emission out to 80 kpc from the galaxy center, and constrain the halo gas mass to be smaller than 4.5 × 1011 M☉. We also measure the temperature of the hot gas as T = 0.64 ± 0.03 keV. Combining our x-ray constraints and the near-infrared and radio measurements in the literature, we find a baryon mass fraction of 0.03–0.05 in UGC 12591, suggesting a missing baryon mass of 70% compared with the cosmological mean value. Combined with another recent measurement in NGC 1961, the result strongly argues that the majority of missing baryons in spiral galaxies do not reside in their hot halos. We also find that UGC 12591 lies significantly below the baryonic Tully–Fisher relationship. Finally, we find that the baryon fractions of massive spiral galaxies are similar to those of galaxy groups with similar masses, indicating that the baryon loss is ultimately controlled by the gravitational potential well. The cooling radius of this gas halo is small, similar to NGC 1961, which argues that the majority of the stellar mass of this galaxy is not assembled as a result of cooling of this gas halo.
Smash products of Calabi–Yau algebras by Hopf algebras

Let H be a Hopf algebra and A be an H-module algebra. This article investigates when the smash product A#H is (skew) Calabi-Yau, has Van den Bergh duality or is Artin-Schelter regular or Gorenstein. In particular, if A and H are skew Calabi-Yau, then so is A#H and its Nakayama automorphism is expressed using the ones of A and H. This is based on a description of the inverse dualising complex of A#H when A is a homologically smooth dg algebra and H is homologically smooth and with invertible antipode. This description is also used to explain the compatibility of standard constructions of Calabi-Yau dg algebras with taking smash products.