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In Mediterranean countries seawater might become a resource for the concrete production for sustainable construction industry. Nowadays its use, since it might induce the corrosion on ordinary carbon steel bars, is prohibited for the realization of reinforced concrete structures. Within the SeaCon Project, the use of seawater as mixing water has been studied in combination with corrosion-resistant reinforcement. This paper, firstly, discusses the influence of chlorides present in the seawater on the concrete properties related to the durability. Afterwards, the corrosion resistance of austenitic (304L and XM-28) and duplex (23-04 and 22-05) stainless steels reinforcing bars, and for comparison of carbon steel, embedded in alkaline and carbonated concretes made with seawater and subjected to different environmental conditions is evaluated. Results showed that seawater accelerated the early strength of concrete, whilst the carbonation penetration, the capillary suction and water absorption were slightly affected. Corrosion tests showed that corrosion did not initiate on 304L, 23-04 and 22-05 stainless steel bars, despite the presence of chlorides since the beginning even in the most aggressive exposure conditions and when concrete was carbonated; XM-28 reinforcement showed a slight change in corrosion behaviour in carbonated concrete exposed to the harshest conditions.

When reinforced concrete structures exposed to marine environments have both water-saturated and aerated parts, for instance, submerged tunnels or parking areas, a macrocell can develop. The electrochemical potential and the corrosion rate of reinforcing steel in the saturated part may increase because of this phenomenon. The goal of this paper was to study the effects of macrocells during corrosion initiation and propagation through numerical simulations of a wall separating a dry environment from seawater. When steel bars are passive, the potential of rebars in saturated concrete is increased by the macrocell and steel depassivation is promoted. After corrosion initiation, steel corrosion rate is increased by several orders of magnitude and the macrocell promotes also the localization of corrosion. A sensitivity analysis was carried out to investigate the influence of the main parameters: the models showed that some electrochemical parameters, such as the cathodic Tafel slope of the steel polarization curve, have a strong influence on the results.

The present study was designed to determine the effects of long-term antialdosterone treatment on cardiac structural and functional alterations, portal and systemic hemodynamic as well as adrenergic dysfunction characterizing Child A cirrhotic patients with F1 esophageal varices. Twenty-two Child A postviral preascitic cirrhotic patients were randomly allocated to 200 mg/day K-Canrenoate (13 patients, age 59.6 +/- 2.2 yr, mean + SEM) or no-drug treatment (9 patients, age 61.8 +/- 2.3) for a 6-month-period. Measurements, which included hepatic venous pressure gradient (HVPG), left ventricular wall thickness, left ventricular end-diastolic volume and diastolic function (LVWT, LVEDV, and E/A ratio, echocardiography), and muscle sympathetic nerve activity (MSNA, microneurography, peroneal nerve), were obtained at baseline and following 6 months of drug or no-drug treatment. Ten healthy age-matched subjects served as controls. Cirrhotic patients were characterized by increased HVPG, LVWT, and MSNA values and by a depressed E/A ratio. K-Canrenoate treatment significantly reduced HVPG (from 15.3 +/- 1.0 to 13.8 +/- 0.8 mmHg, p < 0.05), LVWT (from 21.8 +/- 0.5 to 20.7 +/- 0.6 mm, p < 0.02), and LVEDV (from 99.2 +/- 7 to 86.4 +/- 6 ml, p < 0.01), leaving E/A ratio and MSNA almost unaltered. No significant change was observed in the untreated group of cirrhotic patients followed for 6 months without intervention. These data provide evidence that aldosterone blockade by long-term K-Canrenoate administration improves hepatic hemodynamics by lowering HVPG and ameliorates cardiac structure and function by favoring a reduction in LVWT and LVEDV as well. They also show, however, that this therapeutic intervention neither improves left ventricular diastolic dysfunction nor exerts sympathoinhibitory effects.

Antibiotic-associated diarrhea (AAD) and Clostridium difficile-associated diarrhea (CDAD) are common complications of antibiotic use. Probiotics were effective in preventing AAD and CDAD in several randomized controlled trials. This study was aimed at testing the effect of Saccharomyces boulardii on the occurrence of AAD and CDAD in hospitalized patients. A single-center, randomized, double-blind, placebo-controlled, parallel-group trial was performed. Patients being prescribed antibiotics or on antibiotic therapy for <48 h were eligible. Exclusion criteria were ongoing diarrhea, recent assumption of probiotics, lack of informed consent, inability to ingest capsules, and severe pancreatitis. Patients received a capsule containing S. boulardii or an indistinguishable placebo twice daily within 48 h of beginning antibiotic therapy, continued treatment for 7 days after antibiotic withdrawal, and were followed for 12 weeks after ending antibiotic treatment. Of 562 consecutive eligible patients, 275 patients aged 79.2 ± 9.8 years (134 on placebo) were randomized and 204 aged 78.4 ± 10.0 years (98 on placebo) completed the follow-up. AAD developed in 13.3% (13/98) of the patients receiving placebo and in 15.1% (16/106) of those receiving S. boulardii (odds ratio for S. boulardii vs. placebo, 1.16; 95% confidence interval (CI), 0.53-2.56). Five cases of CDAD occurred, 2 in the placebo group (2.0%) and 3 in the probiotic group (2.8%; odds ratio for S. boulardii vs. placebo, 1.40; 95% CI, 0.23-8.55). There was no difference in mortality rates (12.7% vs. 15.6%, P=0.60). In elderly hospitalized patients, S. boulardii was not effective in preventing the development of AAD.

High-mass star formation theories make distinct predictions on the properties of the prestellar seeds of high-mass stars. Observations of the early stages of high-mass star formation can provide crucial constraints, but they are challenging and scarce. We investigate the properties of the prestellar core population embedded in the high-mass clump AGAL014.492-00.139, and we study the kinematics at the clump and the clump-to-core scales. We have analysed an extensive dataset acquired with the ALMA interferometer. Applying a dendrogram analysis to the Band o-\\( H_2D^+\\) data, we identified 22 cores. We have fitted their average spectra in local-thermodinamic-equilibrium conditions, and we analysed their continuum emission at \\(0.8 \\, mm\\). The cores have transonic to mildly supersonic turbulence levels and appear mostly low-mass, with \\(M_core< 30 \\, M_\\). Furthermore, we have analysed Band 3 observations of the \\( N_2H^+\\) (1-0) transition, which traces the large scale gas kinematics. Using a friend-of-friend algorithm, we identify four main velocity coherent structures, all of which are associated with prestellar and protostellar cores. One of them presents a filament-like structure, and our observations could be consistent with mass accretion towards one of the protostars. In this case, we estimate a mass accretion rate of \\( M_acc 2 10^-4 \\, M_ \\, yr^-1\\). Our results support a clump-fed accretion scenario in the targeted source. The cores in prestellar stage are essentially low-mass, and they appear subvirial and gravitationally bound, unless further support is available for instance due to magnetic fields.

Copyright © 2023 by the authors. The increase in concrete structures’ durability is a milestone to improve the sustainability of buildings and infrastructures. In order to ensure a prolonged service life, it is necessary to detect the deterioration of materials by means of monitoring systems aimed at evaluating not only the penetration of aggressive substances into concrete but also the corrosion of carbon-steel reinforcement. Therefore, proper data collection makes it possible to plan suitable restoration works which can be carried out with traditional or innovative techniques and materials. This work focuses on building heritage and it highlights the most recent findings for the conservation and restoration of reinforced concrete structures and masonry buildings.

ESPRESSO is the new high-resolution spectrograph of ESO's Very-Large Telescope (VLT). It was designed for ultra-high radial-velocity precision and extreme spectral fidelity with the aim of performing exoplanet research and fundamental astrophysical experiments with unprecedented precision and accuracy. It is able to observe with any of the four Unit Telescopes (UT) of the VLT at a spectral resolving power of 140,000 or 190,000 over the 378.2 to 788.7 nm wavelength range, or with all UTs together, turning the VLT into a 16-m diameter equivalent telescope in terms of collecting area, while still providing a resolving power of 70,000. We provide a general description of the ESPRESSO instrument, report on the actual on-sky performance, and present our Guaranteed-Time Observation (GTO) program with its first results. ESPRESSO was installed on the Paranal Observatory in fall 2017. Commissioning (on-sky testing) was conducted between December 2017 and September 2018. The instrument saw its official start of operations on October 1st, 2018, but improvements to the instrument and re-commissioning runs were conducted until July 2019. The measured overall optical throughput of ESPRESSO at 550 nm and a seeing of 0.65 arcsec exceeds the 10% mark under nominal astro-climatic conditions. We demonstrate a radial-velocity precision of better than 25 cm/s during one night and 50 cm/s over several months. These values being limited by photon noise and stellar jitter show that the performanceis compatible with an instrumental precision of 10 cm/s. No difference has been measured across the UTs neither in throughput nor RV precision. The combination of the large collecting telescope area with the efficiency and the exquisite spectral fidelity of ESPRESSO opens a new parameter space in RV measurements, the study of planetary atmospheres, fundamental constants, stellar characterisation and many other fields.

We aim to quantify the effect of chemistry on the infall velocity in the prestellar core L1544. Previous observational studies have found evidence for double-peaked line profiles for the rotational transitions of several molecules, which cannot be accounted for with the models presently available for the physical structure of the source, without ad hoc up-scaling of the infall velocity. We ran one-dimensional hydrodynamical simulations of the collapse of a core with L1544-like properties (in terms of mass and outer radius), using a state-of-the-art chemical model with a very large chemical network combined with an extensive description of molecular line cooling, determined via radiative transfer simulations, with the aim of determining whether these expansions of the simulation setup (as compared to previous models) can lead to a higher infall velocity. After running a series of simulations where the simulation was sequentially simplified, we found that the infall velocity is almost independent of the size of the chemical network or the approach to line cooling. We conclude that chemical evolution does not have a large impact on the infall velocity, and that the higher infall velocities that are implied by observations may be the result of the core being more dynamically evolved than what is now thought, or alternatively the average density in the simulated core is too low. However, chemistry does have a large influence on the lifetime of the core, which varies by about a factor of two across the simulations and grows longer when the chemical network is simplified. Therefore, although the model is subject to several sources of uncertainties, the present results clearly indicate that the use of a small chemical network leads to an incorrect estimate of the core lifetime, which is naturally a critical parameter for the development of chemical complexity in the precollapse phase.

Context. Pre-stellar cores are the birthplaces of Sun-like stars and represent the initial conditions for the assembly of protoplanetary systems. Due to their short lifespans, they are rare. In recent efforts to increase the number of such sources identified in the Solar neighbourhood, we have selected a sample of 40 starless cores from the publicly available core catalogs of the Herschel Gould Belt survey. In this work, we focus on one of the sources that stands out for its high central density: Corona Australis 151. Aims. We use molecular lines that trace dense gas (n>=10^6 cm-3) to confirm the exceptionally high density of this object, to study its physical structure, and to understand its evolutionary stage. Methods. We detected the N2H+ 3-2 and 5-4 transitions, and the N2D+ 3-2, 4-3, and 6-5 lines with the APEX telescope. We use the Herschel continuum data to infer a spherically symmetric model of the core's density and temperature. This is used as input to perform non-local-thermodynamic-equilibrium radiative transfer to fit the observed five lines. Results. Our analysis confirms that this core is characterised by very high densities (a few x 10^7 cm-3 at the centre) and cold temperatures. We infer a high deuteration level of N2D+/N2H+=0.50, indicative of an advanced evolutionary stage. In the large bandwidth covered by the APEX data, we detect several other deuterated species, including CHD2OH, D2CO, and ND3. We also detect multiple sulphurated species that present broader lines with signs of high-velocity wings. Conclusions. The observation of high-velocity wings and the fact that the linewidths of N2H+ and N2D+ become larger with increasing frequency can be interpreted either as an indication of supersonic infall motions developing in the central parts of a very evolved pre-stellar core or as the signature of outflows from a very low luminosity object (VeLLO). *SHORTENED*

Pre-stellar cores are the first steps in the process of star and planet formation. However, the dynamical and chemical evolution of pre-stellar cores is still not well understood. We aim at estimating the central density of the pre-stellar core IRAS16293E and at carrying out an inventory of molecular species towards the density peak of the core. We observed high-\\(J\\) rotational transitions of N\\(_2\\)H\\(^+\\) and N\\(_2\\)D\\(^+\\), and several other molecular lines towards the dust emission peak using the Atacama Pathfinder EXperiment (APEX) telescope, and derived the density and temperature profiles of the core using far-infrared surface brightness maps from \\(Herschel\\). The N\\(_2\\)H\\(^+\\) and N\\(_2\\)D\\(^+\\) lines were analysed by non-LTE radiative transfer modelling. Our best-fit core model consists in a static inner region, embedded in an infalling envelope with an inner radius of approximately 3000 au (21\" at 141 pc). The observed high-J lines of N\\(_2\\)H\\(^+\\) and N\\(_2\\)D\\(^+\\) (with critical densities greater than 10\\(^6\\) cm\\(^-3\\)) turn out to be very sensitive to depletion; the present single-dish observations are best explained with no depletion of N\\(_2\\)H\\(^+\\) and N\\(_2\\)D\\(^+\\) in the inner core. The N\\(_2\\)D\\(^+\\)/N\\(_2\\)H\\(^+\\) ratio that best reproduces our observations is 0.44, one of the largest observed to date in pre-stellar cores. Additionally, half of the molecules that we observed are deuterated isotopologues, confirming the high-level of deuteration towards this source. Non-LTE radiative transfer modelling of N\\(_2\\)H\\(^+\\) and N\\(_2\\)D\\(^+\\) lines proved to be an excellent diagnostic of the chemical structure and dynamics of a pre-stellar core. Probing the physical conditions immediately before the protostellar collapse is a necessary reference for theoretical studies and simulations with the aim of understanding the earliest stages of star and planet formation and the time scale of this process.