MUSE observations of M87: radial gradients for the stellar initial-mass function and the abundance of Sodium

Based on MUSE integral-field data we present evidence for a radial variation at the low-mass end of the stellar initial-mass function (IMF) in the central regions of the giant early-type galaxy NGC4486 (M87). We used state-of-the-art stellar population models and the observed strength of various IMF-sensitive absorption-line features to solve for the best low-mass tapered "bimodal" form of the IMF, while accounting also for radial variations in stellar metallicity, the overall $\alpha$-elements abundance, and the abundance of individual elements such as Ti, O, Na and Ca. Our analysis reveals a strong IMF gradient in M87, corresponding to an exceeding fraction of low-mass stars compared to the case of the Milky Way toward the center of M87 that drops to nearly Milky-way levels by 0.4 $R_e$. This IMF gradient is found to correlate well with both the radial profile for stellar metallicity and for $\alpha$-elements abundance but not with stellar velocity dispersion. Such IMF variations correspond to over a factor two increase in stellar mass-to-light M/L ratio compared to the case of a Milky-way like IMF, consistent with other investigations into IMF gradients in early-type galaxies, including recent dynamical constraints on M/L radial variations in M87 by Oldham & Auger. In addition to constraining the IMF in M87 we also looked into the abundance of Sodium, which turned up to be super-Solar over the entire radial range of our MUSE observations and to exhibit a considerable negative gradient. These findings suggest an additional role of metallicity in boosting the Na-yields in the central, metal-rich regions of M87 during its early and brief star-formation history. Our work adds the case of M87 to the few objects that as of today have radial constraints on their IMF or [Na/Fe] abundance, while also illustrating the accuracy that MUSE could bring to this kind of investigations.Comment: 17 pages, 13 figures, re-submitted for publication on MNRAS following the referee's comment

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Shortcut-to-Adiabatic Controlled-Phase Gate in Rydberg Atoms

A shortcut-to-adiabatic protocol for the realization of a fast and high-fidelity controlled-phase gate in Rydberg atoms is developed. The adiabatic state transfer, driven in the high-blockade limit, is sped up by compensating nonadiabatic transitions via oscillating fields that mimic a counterdiabatic Hamiltonian. High fidelities are obtained in wide parameter regions. The implementation of the bare effective counterdiabatic field, without original adiabatic pulses, enables to bypass gate errors produced by the accumulation of blockade-dependent dynamical phases, making the protocol efficient also at low blockade values. As an application toward quantum algorithms, how the fidelity of the gate impacts the efficiency of a minimal quantum-error correction circuit is analyzed.Comment: Cover story of Annalen der Physik, Volume 535, Issue 1

Elastography, spleen size, and platelet count identify portal hypertension in patients with compensated cirrhosis

BACKGROUND & AIMS: Noninvasive methods are needed to identify clinically significant portal hypertension (CSPH) and esophageal varices (EVs) in patients with compensated cirrhosis. We looked for markers of the presence of CSPH and EVs in patients with cirrhosis. METHODS: We performed a cross-sectional study that included a training set of 117 patients with compensated cirrhosis, confirmed by histology, from a tertiary referral center. Spleen diameter was measured by ultrasound, and liver stiffness (LS) was measured by transient elastography; endoscopy was used as the standard for detection of EVs, and measurements of hepatic venous pressure gradient were used as the standard for identifying CSPH. We assessed the ability of platelet count, spleen diameter, LS, and combinations of these factors (ie, ratio of platelet count to spleen size, and LS × spleen size/platelet count [LSPS]) to identify patients with CSPH and EV. The analysis included 2 new statistical models: the PH risk score and the varices risk score. Results were validated using an independent series of 56 patients with compensated patients from another center. RESULTS: LS was the best single noninvasive variable for identifying patients with CSPH (area under the receiver operating characteristic, 0.883; 95% confidence interval [CI], 0.824-0.943; P < .0001). The area under the receiver operating characteristic value increased when LS was combined with platelet count and spleen size, either as LSPS (0.918; 95% CI, 0.872-0.965; P < .0001) or PH risk score (0.935; 95% CI, 0.893-0.977; P < .0001). More than 80% of patients were accurately classified using LSPS and PH risk score. Analyses of the varices risk score and LSPS were superior to all other noninvasive tests for identifying patients with EVs (area under the receiver operating characteristic, 0.909; 95% CI, 0.841-0.954 and 0.882; 95% CI, 0.810-0.935, respectively); they correctly classified 85% of patients in the training set and 75% in the validation set. CONCLUSIONS: Combined data on LS, spleen diameter, and platelet count can be used to identify patients with compensated cirrhosis most likely to have CSPH and EV

Urinary concentrations of GHB and its novel amino acid and carnitine conjugates following controlled GHB administration to humans

Gamma-hydroxybutyrate (GHB) remains a challenging clinical/forensic toxicology drug. Its rapid elimination to endogenous levels mainly causes this. Especially in drug-facilitated sexual assaults, sample collection often occurs later than the detection window for GHB. We aimed to investigate new GHB conjugates with amino acids (AA), fatty acids, and its organic acid metabolites for their suitability as ingestion/application markers in urine following controlled GHB administration to humans. We used LC–MS/MS for validated quantification of human urine samples collected within two randomized, double-blinded, placebo-controlled crossover studies (GHB 50 mg/kg, 79 participants) at approximately 4.5, 8, 11, and 28 h after intake. We found significant differences (placebo vs. GHB) for all but two analytes at 4.5 h. Eleven hours post GHB administration, GHB, GHB-AAs, 3,4-dihydroxybutyric acid, and glycolic acid still showed significantly higher concentrations; at 28 h only GHB-glycine. Three different discrimination strategies were evaluated: (a) GHB-glycine cut-off concentration (1 µg/mL), (b) metabolite ratios of GHB-glycine/GHB (2.5), and (c) elevation threshold between two urine samples (> 5). Sensitivities were 0.1, 0.3, or 0.5, respectively. Only GHB-glycine showed prolonged detection over GHB, mainly when compared to a second time- and subject-matched urine sample (strategy c)

COVID-19 pandemic experiences, ethical conflict and decision-making process in critical care professionals (Quali-Ethics-COVID-19 Research Part 1): An international qualitative study

Aim and Objectives: The aim of this study was to explore the sources of ethical conflict and the decision-making processes of ICU nurses and physicians during the first and subsequent waves of the COVID-19 pandemic. Background: Depside several studies exploring ethical conflicts during COVID-19 pandemic, few studies have explored in depth the perceptions and experiences of critical care professionals regarding these conflicts, the decision-making process or which have analysed the complexity of actually implementing the recommendations of scientific societies and professional/healthcare institutions in interdisciplinary samples. Design: A descriptive phenomenological study. Methods: Thirty-eight in-depth interviews were conducted with critical care nurses and physicians from five hospitals in Spain and Italy between December 2020 and May 2021. A thematic content analysis of the interview transcripts was conducted by two researchers. Consolidated criteria for reporting qualitative research (COREQ) were employed to ensure the quality and transparency of this study. Results: Two main themes emerged as sources of ethical conflict: the approach to end of life in exceptional circumstances and the lack of humanisation and care resources. The former comprised two subthemes: end-of-life care and withholding and withdrawal of life-sustaining treatment; the latter comprised three subthemes: the impossibility of guaranteeing the same opportunities to all, fear of contagion as a barrier to taking decisions and the need to humanise care. Conclusions: Professionals sought to take their decisions in line with professional ethics and bioethical principles, but, nevertheless, they experienced moral dilemmas and moral distress when not being able to care for, or to treat, their patients as they believed fit. Relevance to Clinical Practice: Further education and training are recommended on the provision of end-of-life and post mortem care, effective communication techniques via video calls, disclosure of bad news and bioethical models for decision-making in highly demanding situations of uncertainty, such as those experienced during the COVID-19 pandemic

SDSS-IV MaNGA: the spatial distribution of star formation and its dependence on mass, structure, and environment

We study the spatially resolved star formation of 1494 galaxies in the SDSS-IV MaNGA Survey. Star formation rates (SFRs) are calculated using a two-step process, using H α in star-forming regions and Dn4000 in regions identified as active galactic nucleus/low-ionization (nuclear) emission region [AGN/LI(N)ER] or lineless. The roles of secular and environmental quenching processes are investigated by studying the dependence of the radial profiles of specific star formation rate on stellar mass, galaxy structure, and environment. We report on the existence of ‘centrally suppressed’ galaxies, which have suppressed Specific Star Formation Rate (SSFR) in their cores compared to their discs. The profiles of centrally suppressed and unsuppressed galaxies are distributed in a bimodal way. Galaxies with high stellar mass and core velocity dispersion are found to be much more likely to be centrally suppressed than low-mass galaxies, and we show that this is related to morphology and the presence of AGN/LI(N)ER like emission. Centrally suppressed galaxies also display lower star formation at all radii compared to unsuppressed galaxies. The profiles of central and satellite galaxies are also compared, and we find that satellite galaxies experience lower specific star formation rates at all radii than central galaxies. This uniform suppression could be a signal of the stripping of hot halo gas in the process known as strangulation. We find that satellites are not more likely to be suppressed in their cores than centrals, indicating that the core suppression is an entirely internal process. We find no correlation between the local environment density and the profiles of star formation rate surface density