Energy feedback, either from active galactic nuclei (AGNs) or from supernovae, is required to understand galaxy formation within a Λ-cold dark matter cosmology. We study a sample of 127 low-mass ...galaxies, comparing their stellar population properties to the mass of the central supermassive black hole, in order to investigate the effect of AGN feedback. We find a loose coupling between star formation history and black hole mass, which seems to suggest that AGN activity does not dominate baryonic cooling in low-mass galaxies. We also find that a break in the - relation marks a transitional stellar mass, Mtrans = (3.4 2.1) × 1010 , remarkably similar to . Our results are in agreement with a bi-modal star formation process where the AGN-dominated feedback of high-mass galaxies transitions toward a supernovae-driven regime in low-mass systems, as suggested by numerical simulations.
Background
The SCORTEN score is a specific predictor of mortality for patients with Stevens–Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN). There is little evidence in support of the common ...immunomodulating therapies for SJS/TEN.
Objectives
To systematically assess the effectiveness of several therapies for SJS/TEN through the SCORTEN score.
Methods
Databases were searched for original studies on the use of SCORTEN. Six meta‐analyses were carried out on patients with SJS/TEN who received supportive care only or in combination with immunomodulating drugs: corticosteroids, cyclosporine, etanercept, immunoglobulins or a combination of corticosteroids with immunoglobulins. A multivariate meta‐regression and a network meta‐analysis were also performed.
Results
Of 3893 studies identified, fifty‐two involving 2466 patients with SJS/TEN were preselected. Data from thirty‐eight of these studies (1827 patients) were finally pooled, and results log(SMR) from meta‐analyses were as follows: −0.13 (95% CI, −0.42,0.16) for corticosteroids, −0.39 (95% CI, −0.87,0.09) for immunoglobulins, 0.13 (95% CI, −0.15,0.40) for supportive treatment, −0.88 (95% CI, −1.47, −0.29) for cyclosporine, −0.95 (95% CI, −1.82, −0.07) for etanercept and − 0.56 (95% CI, −0.94, −0.19) for immunoglobulins plus corticosteroids. The meta‐regression analysis confirmed that cyclosporine and immunoglobulins plus corticosteroids were associated with less deaths than predicted by SCORTEN. In the network meta‐analysis, no treatment achieved a significant reduction in the SMR.
Limitations
Heterogeneity and quality of the included studies.
Conclusions
Some treatments for SJS/TEN show a better performance, but there is not sufficient evidence to recommend its widespread use in all patients.
ABSTRACT
Using new long-slit spectroscopy obtained with X-Shooter at ESO-VLT, we study, for the first time, radial gradients of optical and near-infrared initial mass function (IMF)-sensitive ...features in a representative sample of galaxies at the very high mass end of the galaxy population. The sample consists of seven early-type galaxies (ETGs) at z ∼ 0.05, with central velocity dispersion in the range 300 ≲ σ ≲ 350 km s−1. Using state-of-the-art stellar population synthesis models, we fit a number of spectral indices, from different chemical species (including TiO and Na indices), to constrain the IMF slope (i.e. the fraction of low-mass stars), as a function of galactocentric distance, over a radial range out to ∼4 kpc. ETGs in our sample show a significant correlation of IMF slope and surface mass density. The bottom-heavy population (i.e. an excess of low-mass stars in the IMF) is confined to central galaxy regions with surface mass density above $\rm \sim 10^{10}\, M_\odot \, kpc^{-2}$, or, alternatively, within a characteristic radius of ∼2 kpc. Radial distance, in physical units, and surface mass density are the best correlators to IMF variations, with respect to other dynamical (e.g. velocity dispersion) and stellar population (e.g. metallicity) properties. Our results for the most massive galaxies suggest that there is no single parameter that fully explains variations in the stellar IMF, but IMF radial profiles at z ∼ 0 rather result from the complex formation and mass accretion history of galaxy inner and outer regions.
Summary
Background
The cutaneous manifestations of COVID‐19 disease are poorly characterized.
Objectives
To describe the cutaneous manifestations of COVID‐19 disease and to relate them to other ...clinical findings.
Methods
We carried out a nationwide case collection survey of images and clinical data. Using a consensus we described five clinical patterns. We later described the association of these patterns with patient demographics, the timing in relation to symptoms of the disease, the severity and the prognosis.
Results
The lesions may be classified as acral areas of erythema with vesicles or pustules (pseudo‐chilblain) (19%), other vesicular eruptions (9%), urticarial lesions (19%), maculopapular eruptions (47%) and livedo or necrosis (6%). Vesicular eruptions appear early in the course of the disease (15% before other symptoms). The pseudo‐chilblain pattern frequently appears late in the evolution of the COVID‐19 disease (59% after other symptoms), while the rest tend to appear with other symptoms of COVID‐19. The severity of COVID‐19 shows a gradient from less severe disease in acral lesions to more severe in the latter groups. The results are similar for confirmed and suspected cases, in terms of both clinical and epidemiological findings. Alternative diagnoses are discussed but seem unlikely for the most specific patterns (pseudo‐chilblain and vesicular).
Conclusions
We provide a description of the cutaneous manifestations associated with COVID‐19 infection. These may help clinicians approach patients with the disease and recognize cases presenting with few symptoms.
What is already known about this topic?
Previous descriptions of cutaneous manifestations of COVID‐19 were case reports and mostly lacked illustrations.
What does this study add?
We describe a large, representative sample of patients with unexplained skin manifestations and a diagnosis of COVID‐19, using a consensus method to define morphological patterns associated with COVID‐19.
We describe five clinical patterns associated with different patient demographics, timing and prognosis, and provide illustrations of these patterns to allow for easy recognition.
Linked Editorial: Hay et al. Br J Dermatol 2020; 183:3–4.
Plain language summary available online
In this Paper, we describe how we use stellar dynamics information to constrain the shape of the stellar initial mass function (IMF) in a sample of 27 early-type galaxies from the CALIFA survey. We ...obtain dynamical and stellar mass-to-light ratios, ... and ..., over a homogenous aperture of 0.5 R sub( e). We use the constraint ... to test two IMF shapes within the framework of the extended MILES stellar population models. We rule out a single power-law IMF shape for 75 per cent of the galaxies in our sample. Conversely, we find that a double power-law IMF shape with a varying high-mass end slope is compatible (within ...) with 95 per cent of the galaxies. We also show that dynamical and stellar IMF mismatch factors give consistent results for the systematic variation of the IMF in these galaxies. (ProQuest: ... denotes formulae/symbols omitted.)
Nuclear star clusters (NSCs) are the densest stellar systems in the Universe and are found in the centres of all types of galaxies. They are thought to form via mergers of star clusters such as ...ancient globular clusters (GCs) that spiral to the centre as a result of dynamical friction or through in situ star formation directly at the galaxy centre. There is evidence that both paths occur, but the relative contribution of either channel and their correlation with galaxy properties are not yet constrained observationally. Our aim was to derive the dominant NSC formation channel for a sample of 25 nucleated galaxies, mostly in the Fornax galaxy cluster, with stellar masses between
M
gal
∼ 10
8
and 10
10.5
M
⊙
and NSC masses between
M
NSC
∼ 10
5
and 10
8.5
M
⊙
. Using Multi-Unit Spectroscopic Explorer data from the Fornax 3D survey and the ESO archive, we derived star formation histories, mean ages, and metallicities of NSCs, and compared them to the host galaxies. In many low-mass galaxies, the NSCs are significantly more metal poor than their hosts, with properties similar to GCs. In contrast, in the massive galaxies we find diverse star formation histories and cases of ongoing or recent in situ star formation. Massive NSCs (> 10
7
M
⊙
) occupy a different region in the mass–metallicity diagram than lower-mass NSCs and GCs, indicating a different enrichment history. We find a clear transition of the dominant NSC formation channel with both galaxy and NSC mass. We hypothesise that while GC accretion forms the NSCs of the dwarf galaxies, central star formation is responsible for the efficient mass build up in the most massive NSCs in our sample. At intermediate masses both channels can contribute. The transition between these formation channels seems to occur at galaxy masses
M
gal
∼ 10
9
M
⊙
and NSC masses
M
NSC
∼ 10
7
M
⊙
.
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