We present a simulation of the cosmic evolution of the atomic and molecular phases of the cold hydrogen gas in about 3 X 107 galaxies, obtained by postprocessing the virtual galaxy catalog produced ...by De Lucia & Blaizot on the Millennium Simulation of cosmic structure. Our method uses a set of physical prescriptions to assign neutral atomic hydrogen (H I) and molecular hydrogen (H2) to galaxies, based on their total cold gas masses and a few additional galaxy properties. These prescriptions are specially designed for large cosmological simulations, where, given current computational limitations, individual galaxies can only be represented by simplistic model objects with a few global properties. Our recipes allow us to (1) split total cold gas masses between H I, H2, and helium, (2) assign realistic sizes to both the H I and H2 disks, and (3) evaluate the corresponding velocity profiles and shapes of the characteristic radio emission lines. The results presented in this paper include the local H I and H2 mass functions, the CO luminosity function, the cold gas mass-diameter relation, and the Tully-Fisher relation (TFR), which all match recent observational data from the local universe. We also present high-redshift predictions of cold gas diameters and the TFR, both of which appear to evolve markedly with redshift.
We investigate the galaxy population in simulated protocluster regions using a semi-analytic model of galaxy formation, coupled to merger-trees extracted from N-body simulations. We select the most ...massive clusters at redshift z = 0 from our set of simulations, and follow their main progenitors back in time. The analysis shows that protocluster regions are dominated by central galaxies and their number decreases with time as many become satellites, clustering around the central object. In agreement with observations, we find an increasing velocity dispersion with cosmic time, the increase being faster for satellites. The analysis shows that protoclusters are very extended regions, ≳20 Mpc at z ≳ 1. The fraction of galaxies in protocluster regions that are not progenitor of cluster galaxies varies with redshift, stellar mass and area considered. It is about 20–30 per cent for galaxies with stellar mass ∼109 M⊙, while negligible for the most massive galaxies considered. Nevertheless, these objects have properties similar to those of progenitors. We investigate the building-up of the passive sequence in clusters, and find that their progenitors are on average always active at any redshift of interest of protoclusters. The main mechanism which quenches their star formation is the removal of the hot gas reservoir at the time of accretion. The later galaxies are accreted (become satellite), and the more the cold gas available, the longer the time spent as active. Central galaxies are active over all redshift range considered, although a non-negligible fraction of them become passive at redshift z < 1, due to strong feedback from active galactic nuclei.
We present new constraints on the relationship between galaxies and their host dark matter haloes, measured from the location of the peak of the stellar-to-halo mass ratio (SHMR), up to the most ...massive galaxy clusters at redshift z ∼ 0.8 and over a volume of nearly 0.1 Gpc3. We use a unique combination of deep observations in the CFHTLenS/VIPERS field from the near-UV to the near-IR, supplemented by ∼60 000 secure spectroscopic redshifts, analysing galaxy clustering, galaxy–galaxy lensing and the stellar mass function. We interpret our measurements within the halo occupation distribution (HOD) framework, separating the contributions from central and satellite galaxies. We find that the SHMR for the central galaxies peaks at
$M_{\rm h, peak} = 1.9^{+0.2}_{-0.1}\times 10^{12}{\,{\rm M}_{{\odot }}}$
with an amplitude of 0.025, which decreases to ∼0.001 for massive haloes (
${{{M}_{\rm h}}}> 10^{14} {\,{\rm M}_{{\odot }}}$
). Compared to central galaxies only, the total SHMR (including satellites) is boosted by a factor of 10 in the high-mass regime (cluster-size haloes), a result consistent with cluster analyses from the literature based on fully independent methods. After properly accounting for differences in modelling, we have compared our results with a large number of results from the literature up to z = 1: we find good general agreement, independently of the method used, within the typical stellar-mass systematic errors at low to intermediate mass (
${{{M}_{\rm \star }}}<10^{11} {\,{\rm M}_{{\odot }}}$
) and the statistical errors above. We have also compared our SHMR results to semi-analytic simulations and found that the SHMR is tilted compared to our measurements in such a way that they over- (under-) predict star formation efficiency in central (satellite) galaxies.
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► The
n-butanol one-step synthesis requires adjacent acid and medium basic sites. ► These pairs are generated by Al in the MgO lattice and also Mg in the γ-Al
2O
3. ► The C4 synthesis ...from ethanol does not require strong basic sites. ► High Mg concentration promotes the hydrogenation of C4 compounds to
n-butanol.
n-Butanol is used in a wide range of applications, especially for the production of paint, solvents and plasticizers. Recently, some companies have proposed the use of
n-butanol as a fuel, which can be employed pure or blended with gasoline or diesel. At present, there is great interest in developing a one-step process that generates
n-butanol from ethanol. Some works showed that Mg–Al mixed oxides are very promising catalysts for this matter. Analyzing the physical–chemical properties of these catalysts, this work aims at further studying this reaction. The Mg–Al mixed oxides were obtained by thermal decomposition of hydrotalcites employing two Mg/Al different ratios. Magnesium oxide (MgO) and alumina (Al
2O
3) were also prepared following the same synthetic route used for the Mg–Al mixed oxides. The synthesized samples were characterized by the following techniques: XRD, NMR, BET and XRF. The acid and basic properties of the samples were also analyzed employing probe molecules. The catalytic tests were performed using a fixed bed reactor at atmospheric pressure. It was verified that the Mg and Al mixed oxides are able to promote the synthesis of C4 compounds from ethanol. Adjacent acid and medium basic sites are needed in order to generate the intermediate compounds. These pairs of acid and medium basic sites are obtained by the insertion of Al in the MgO lattice or in consequence of the presence of Mg in the γ-Al
2O
3 lattice. It was observed that the higher the concentration of Mg is, the higher the hydrogenation capacity of the catalyst, since a greater selectivity to
n-butanol was observed. Strong basic sites and a specific superficial atomic arrangement seem not to be essential for the synthesis of C4 from ethanol.
Abstract
Gravitational lensing by clusters of galaxies offers a powerful probe of their structure and mass distribution. Several research groups have developed techniques independently to achieve ...this goal. While these methods have all provided remarkably high-precision mass maps, particularly with exquisite imaging data from the Hubble Space Telescope (HST), the reconstructions themselves have never been directly compared. In this paper, we present for the first time a detailed comparison of methodologies for fidelity, accuracy and precision. For this collaborative exercise, the lens modelling community was provided simulated cluster images that mimic the depth and resolution of the ongoing HST Frontier Fields. The results of the submitted reconstructions with the un-blinded true mass profile of these two clusters are presented here. Parametric, free-form and hybrid techniques have been deployed by the participating groups and we detail the strengths and trade-offs in accuracy and systematics that arise for each methodology. We note in conclusion that several properties of the lensing clusters are recovered equally well by most of the lensing techniques compared in this study. For example, the reconstruction of azimuthally averaged density and mass profiles by both parametric and free-form methods matches the input models at the level of ∼10 per cent. Parametric techniques are generally better at recovering the 2D maps of the convergence and of the magnification. For the best-performing algorithms, the accuracy in the magnification estimate is ∼10 per cent at μtrue = 3 and it degrades to ∼30 per cent at μtrue ∼ 10.
In this paper, we carry out a detailed analysis of the performance of two different methods to identify the diffuse stellar light in cosmological hydrodynamical simulations of galaxy clusters. One ...method is based on a dynamical analysis of the stellar component, which separates the brightest central galaxy (BCG) from the stellar component not gravitationally bound to any galaxy, what we call 'diffuse stellar component' (DSC). The second method is closer to techniques commonly employed in observational studies. We generate mock images from simulations, and assume a standard surface brightness limit (SBL) to disentangle the BCG from the intra-cluster light (ICL). Both the dynamical method and the method based on the SBL criterion are applied to the same set of hydrodynamical simulations for a large sample of about 80 galaxy clusters. We analyse two sets of radiative simulations: a first set includes the effect of cooling, star formation, chemical enrichment and galactic outflows triggered by supernova feedback (CSF set); a second one also includes the effect of thermal feedback from active galactic nuclei triggered by gas accretion on to supermassive black holes (AGN set). We find significant differences between the ICL and DSC fractions computed with the two corresponding methods, which amounts to about a factor of 2 for the AGN simulations, and a factor of 4 for the CSF set. We also find that the inclusion of AGN feedback boosts the DSC and ICL fractions by a factor of 1.5-2, respectively, while leaving the BCG+ICL and BCG+DSC mass fraction almost unchanged. The sum of the BCG and DSC mass stellar mass fraction is found to decrease from ∼80 per cent in galaxy groups to ∼60 per cent in rich clusters, thus in excess of that found from observational analysis. We identify the average SBLs that yield the ICL fraction from the SBL method close to the DSC fraction from the dynamical method. These SBLs turn out to be brighter in the CSF than in the AGN simulations. This is consistent with the finding that AGN feedback makes BCGs to be less massive and with shallower density profiles than in the CSF simulations. The BCG stellar components, as identified by both methods, are slightly older and more metal-rich than the stars in the diffuse component. Relaxed clusters have somewhat higher stellar mass fractions in the diffuse component. The metallicity and age of both the BCG and diffuse components in relaxed clusters are also richer in metals and older.
Human impacts outpace natural processes in the Amazon Albert, James S; Carnaval, Ana C; Flantua, Suzette G A ...
Science (American Association for the Advancement of Science),
01/2023, Volume:
379, Issue:
6630
Journal Article
Peer reviewed
Amazonian environments are being degraded by modern industrial and agricultural activities at a pace far above anything previously known, imperiling its vast biodiversity reserves and globally ...important ecosystem services. The most substantial threats come from regional deforestation, because of export market demands, and global climate change. The Amazon is currently perched to transition rapidly from a largely forested to a nonforested landscape. These changes are happening much too rapidly for Amazonian species, peoples, and ecosystems to respond adaptively. Policies to prevent the worst outcomes are known and must be enacted immediately. We now need political will and leadership to act on this information. To fail the Amazon is to fail the biosphere, and we fail to act at our peril.
Between 2017 and 2021, the Brazilian Unified Health System (BUHS) administered a total of 527,903,302 doses of immunizations. Each immunization results in the presence of a residual volume (RV) due ...to syringe dead space (DS). The International Organization for Standardization 7886-1 allows a DS of up to 0.07mL in sterile single-use hypodermic syringes with volumes less than 5mL. This study aims to quantify the DS of immunization devices used in Brazil, study the best combinations of needles and syringes to minimize RV, estimate the number of wasted doses from 2017 to 2021, and evaluate the impact on the BUHS. Pneumococcal 10 vaccine with a 25x6mm needle and a regular 1mL syringe exhibited a significantly higher average RV (0.0826mL) and waste rate (14.42%). It was observed that for some intramuscular vaccines, there is less waste when using a 20x5.5mm needle compared to a 25x6mm needle. The use of syringes with plunger stoppers that penetrate the syringe barrel, denoted as low dead space syringes, results in less RV and an estimated difference in the waste rate of approximately 10% compared to the regular syringe. The estimated number of wasted doses from 2017 to 2021 by BUHS is approximately 32 million doses.Between 2017 and 2021, the Brazilian Unified Health System (BUHS) administered a total of 527,903,302 doses of immunizations. Each immunization results in the presence of a residual volume (RV) due to syringe dead space (DS). The International Organization for Standardization 7886-1 allows a DS of up to 0.07mL in sterile single-use hypodermic syringes with volumes less than 5mL. This study aims to quantify the DS of immunization devices used in Brazil, study the best combinations of needles and syringes to minimize RV, estimate the number of wasted doses from 2017 to 2021, and evaluate the impact on the BUHS. Pneumococcal 10 vaccine with a 25x6mm needle and a regular 1mL syringe exhibited a significantly higher average RV (0.0826mL) and waste rate (14.42%). It was observed that for some intramuscular vaccines, there is less waste when using a 20x5.5mm needle compared to a 25x6mm needle. The use of syringes with plunger stoppers that penetrate the syringe barrel, denoted as low dead space syringes, results in less RV and an estimated difference in the waste rate of approximately 10% compared to the regular syringe. The estimated number of wasted doses from 2017 to 2021 by BUHS is approximately 32 million doses.
Pt(II) and Pd(II) coordinating N‐donor ligands have been extensively studied as anticancer agents after the success of cisplatin. In this work, a novel bidentate N‐donor ligand, the ...N‐4‐(phenylmethoxy)phenylmethyl‐2‐pyridinemethanamine, was designed to explore the antiparasitic, antiviral and antitumor activity of its Pt(II) and Pd(II) complexes. Chemical and spectroscopic characterization confirm the formation of MLCl2 complexes, where M=Pt(II) and Pd(II). Single crystal X‐ray diffraction confirmed a square‐planar geometry for the Pd(II) complex. Spectroscopic characterization of the Pt(II) complex suggests a similar structure. 1H NMR, 195Pt NMR and HR‐ESI‐MS(+) analysis of DMSO solution of complexes indicated that both compounds exchange the chloride trans to the pyridine for a solvent molecule with different reaction rates. The ligand and the two complexes were tested for in vitro antitumoral, antileishmanial, and antiviral activity. The Pt(II) complex resulted in a GI50 of 10.5 μM against the NCI/ADR‐RES (multidrug‐resistant ovarian carcinoma) cell line. The ligand and the Pd(II) complex showed good anti‐SARS‐CoV‐2 activity with around 65 % reduction in viral replication at a concentration of 50 μM.
The novel N‐4‐(phenylmethoxy)phenylmethyl‐2‐pyridinemethanamine (L) coordinates Pt(II) and Pd(II) giving two complexes of formula MLCl2. The ligand and Pd(II) complex impaired 65 % and 59 %, respectively, of SARS‐CoV‐2 replication at the viable concentrations of 50 μM. In the in vitro antitumor evaluation, Pt(II) complex showed significant cytotoxicity with a GI50 of 10 μM, and no selectivity in the panel of tumor cells evaluated.
•Optimisation of enzymatic activity for the production of quercetin-3-glucoside.•Hesperidinase allowed higher conversion rates than naringinase.•Quercetin-3-glucoside has higher antiproliferative ...activity than rutin or quercetin.•Quercetin-3-glucoside shows high antioxidant activity evaluated by the DPPH method.
Bioavailability and biological properties of flavonoid glycosides can be improved after the enzymatic hydrolysis of specific glycosyl groups. In this study, we evaluate the antioxidant and antiproliferative potential of rutin after enzymatic hydrolysis performed by α-l-rhamnosidases (hesperidinase from Penicillium sp. and naringinase from Penicillium decumbens) previously heated at 70°C for 30min to inactivate the undesirable β-d-glucosidase activity. The highest in vitro antioxidant activity determined by DPPH radical scavenging was achieved with rutin hydrolyzed by hesperidinase. Rutin was predominantly bioconverted into quercetin-3-glucoside. There was no statistical difference between xanthine oxidase inhibition by rutin before and after hydrolysis. However, in vitro inhibitory activity against ten human tumor cell lines showed that hydrolyzed rutin exerted a more potent antiproliferative effect than quercetin and rutin on various cancer cell lines, specially glioma, and ovarian and breast adenocarcinomas. These results indicate that quercetin-3-glucoside could be a promising functional derivative obtained by rutin hydrolysis.
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