Context. Recent observations suggest a double-branch behaviour of Li/H versus metallicity in the local thick and thin discs. This is reminiscent of the corresponding O/Fe versus Fe/H behaviour, which ...has been explained as resulting from radial migration in the Milky Way disc. Aims. We study here the role of radial migration in shaping these observations. Methods. We use a semi-analytical model of disc evolution with updated chemical yields and parameterised radial migration. We explore the cases of long-lived (red giants of a few Gy lifetime) and shorter-lived (asymptotic giant branch stars of several 108 yr) stellar sources of Li, as well as those of low and high primordial Li. We show that both factors play a key role in the overall Li evolution. Results. We find that the observed two-branch Li behaviour is only directly obtained in the case of long-lived stellar Li sources and low primordial Li. In all other cases, the data imply systematic Li depletion in stellar envelopes, thus no simple picture of the Li evolution can be obtained. This concerns also the reported Li/H decrease at supersolar metallicities.
The Shank3 gene encodes a scaffolding protein that anchors multiple elements of the postsynaptic density at the synapse. Previous attempts to delete the Shank3 gene have not resulted in a complete ...loss of the predominant naturally occurring Shank3 isoforms. We have now characterized a homozygous Shank3 mutation in mice that deletes exon 21, including the Homer binding domain. In the homozygous state, deletion of exon 21 results in loss of the major naturally occurring Shank3 protein bands detected by C-terminal and N-terminal antibodies, allowing us to more definitively examine the role of Shank3 in synaptic function and behavior. This loss of Shank3 leads to an increased localization of mGluR5 to both synaptosome and postsynaptic density-enriched fractions in the hippocampus. These mice exhibit a decrease in NMDA/AMPA excitatory postsynaptic current ratio in area CA1 of the hippocampus, reduced long-term potentiation in area CA1, and deficits in hippocampus-dependent spatial learning and memory. In addition, these mice also exhibit motor-coordination deficits, hypersensitivity to heat, novelty avoidance, altered locomotor response to novelty, and minimal social abnormalities. These data suggest that Shank3 isoforms are required for normal synaptic transmission/plasticity in the hippocampus, as well as hippocampus-dependent spatial learning and memory.
Context. There have been conflicting results with respect to the extent that radial migration has played in the evolution of the Galaxy. Additionally, observations of the solar neighborhood have ...shown evidence of a merger in the past history of the Milky Way that drives enhanced radial migration. Aims. We attempt to determine the relative fraction of stars that have undergone significant radial migration by studying the orbital properties of metal-rich (Fe/H > 0.1) stars within 2 kpc of the Sun. We also aim to investigate the kinematic properties, such as velocity dispersion and orbital parameters, of stellar populations near the Sun as a function of Mg/Fe and Fe/H, which could show evidence of a major merger in the past history of the Milky Way. Methods. We used a sample of more than 3000 stars selected from the fourth internal data release of the Gaia-ESO Survey. We used the stellar parameters from the Gaia-ESO Survey along with proper motions from PPMXL to determine distances, kinematics, and orbital properties for these stars to analyze the chemodynamic properties of stellar populations near the Sun. Results. Analyzing the kinematics of the most metal-rich stars (Fe/H > 0.1), we find that more than half have small eccentricities (e< 0.2) or are on nearly circular orbits. Slightly more than 20% of the metal-rich stars have perigalacticons Rp> 7 kpc. We find that the highest Mg/Fe, metal-poor populations have lower vertical and radial velocity dispersions compared to lower Mg/Fe populations of similar metallicity by ~10 km s-1. The median eccentricity increases linearly with Mg/Fe across all metallicities, while the perigalacticon decreases with increasing Mg/Fe for all metallicities. Finally, the most Mg/Fe-rich stars are found to have significant asymmetric drift and rotate more than 40 km s-1 slower than stars with lower Mg/Fe ratios. Conclusions. While our results cannot constrain how far stars have migrated, we propose that migration processes are likely to have played an important role in the evolution of the Milky Way, with metal-rich stars migrating from the inner disk toward to solar neighborhood and past mergers potentially driving enhanced migration of older stellar populations in the disk.
To determine the role of the CCL2/CCR2 axis and inflammatory monocytes (CCR2(+)/CD14(+)) as immunotherapeutic targets in the treatment of pancreatic cancer.
Survival analysis was conducted to ...determine if the prevalence of preoperative blood monocytes correlates with survival in patients with pancreatic cancer following tumor resection. Inflammatory monocyte prevalence in the blood and bone marrow of patients with pancreatic cancer and controls was compared. The immunosuppressive properties of inflammatory monocytes and macrophages in the blood and tumors, respectively, of patients with pancreatic cancer were assessed. CCL2 expression by human pancreatic cancer tumors was compared with normal pancreas. A novel CCR2 inhibitor (PF-04136309) was tested in an orthotopic model of murine pancreatic cancer.
Monocyte prevalence in the peripheral blood correlates inversely with survival, and low monocyte prevalence is an independent predictor of increased survival in patients with pancreatic cancer with resected tumors. Inflammatory monocytes are increased in the blood and decreased in the bone marrow of patients with pancreatic cancer compared with controls. An increased ratio of inflammatory monocytes in the blood versus the bone marrow is a novel predictor of decreased patient survival following tumor resection. Human pancreatic cancer produces CCL2, and immunosuppressive CCR2(+) macrophages infiltrate these tumors. Patients with tumors that exhibit high CCL2 expression/low CD8 T-cell infiltrate have significantly decreased survival. In mice, CCR2 blockade depletes inflammatory monocytes and macrophages from the primary tumor and premetastatic liver resulting in enhanced antitumor immunity, decreased tumor growth, and reduced metastasis.
Inflammatory monocyte recruitment is critical to pancreatic cancer progression, and targeting CCR2 may be an effective immunotherapeutic strategy in this disease.
Fusion edge plasmas can be far from thermal equilibrium and require the use of a non-linear collision operator for accurate numerical simulations. In this article, the non-linear single-species ...Fokker–Planck–Landau collision operator developed by Yoon and Chang (2014) 9 is generalized to include multiple particle species. The finite volume discretization used in this work naturally yields exact conservation of mass, momentum, and energy. The implementation of this new non-linear Fokker–Planck–Landau operator in the gyrokinetic particle-in-cell codes XGC1 and XGCa is described and results of a verification study are discussed. Finally, the numerical techniques that make our non-linear collision operator viable on high-performance computing systems are described, including specialized load balancing algorithms and nested OpenMP parallelization. The collision operator's good weak and strong scaling behavior are shown.
A substantial body of evidence supports the use of integrated treatments for posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD). Integrated trauma-focused exposure therapies reduce ...PTSD symptoms more than comparison treatments, including integrated coping skills therapies, but demonstrate lower attendance, raising questions regarding the relationships between attendance, outcomes, and treatment type. We aimed to examine these relationships in a RCT comparing integrated prolonged exposure (Concurrent Treatment for PTSD and Substance Use Disorders Using Prolonged Exposure, COPE; n = 58), to integrated coping skills therapy (Seeking Safety, SS; n = 52) offered in 12 sessions, with an option to extend up to four additional sessions. Participants were categorized based on number of sessions attended (0–4; 5–8; 9–12; 13–16). Multilevel modeling revealed that only when examining therapy attendance segments individually, clinical outcomes were comparable across treatments except in the 9–12 group, with COPE resulting in greater reductions in PTSD symptoms (p < 0.001), but not in alcohol use. Extending past 12 sessions was not associated with additional clinically meaningful symptom improvement for either treatment. These results suggest that attending a complete or near complete course of exposure therapy may enhance PTSD outcomes relative to non-trauma-focused therapies.
•Relationship between attendance and outcomes in integrated treatment is complicated.•Exposure outperformed coping therapy for PTSD for those who completed 9–12 sessions.•Extending beyond 12 sessions was not associated with further meaningful improvement.
Context. The pattern of chemical abundance ratios in stellar populations of the Milky Way is a fingerprint of the Galactic chemical history. In order to interpret such chemical fossils of Galactic ...archaeology, chemical evolution models have to be developed. However, despite the complex physics included in the most recent models, significant discrepancies between models and observations are widely encountered. Aims. The aim of this paper is to characterise the abundance patterns of five iron-peak elements (Mn, Fe, Ni, Cu, and Zn) for which the stellar origin and chemical evolution are still debated. Methods. We automatically derived iron peak (Mn, Fe, Ni, Cu, and Zn) and α element (Mg) chemical abundances for 4666 stars, adopting classical LTE spectral synthesis and 1D atmospheric models. Our observational data collection is composed of high-resolution, high signal-to-noise ratios HARPS and FEROS spectra, which were previously parametrised by the AMBRE project. Results. We used the bimodal distribution of the magnesium-to-iron abundance ratios to chemically classify our sample stars into different Galactic substructures: thin disc, metal-poor and high-α metal rich, high-α, and low-α metal-poor populations. Both high-α and low-α metal-poor populations are fully distinct in Mg, Cu, and Zn, but these substructures are statistically indistinguishable in Mn and Ni. Thin disc trends of Ni/Fe and Cu/Fe are very similar and show a small increase at supersolar metallicities. Also, both thin and thick disc trends of Ni and Cu are very similar and indistinguishable. Yet, Mn looks very different from Ni and Cu. Mn/Fe trends of thin and thick discs actually have noticeable differences: the thin disc is slightly Mn richer than the thick disc. The Zn/Fe trends look very similar to those of α/Fe trends. The typical dispersion of results in both discs is low (≈0.05 dex for Mg, Mn, and Cu/Fe) and is even much lower for Ni/Fe (≈0.035 dex). Conclusions. It is clearly demonstrated that Zn is an α-like element and could be used to separate thin and thick disc stars. Moreover, we show that the Mn/Mg ratio could also be a very good tool for tagging Galactic substructures. From the comparison with Galactic chemical evolutionary models, we conclude that some recent models can partially reproduce the observed Mg, Zn, and, Cu behaviours in thin and thick discs and metal-poor sequences. Models mostly fail to reproduce Mn and Ni in all metallicity domains, however, models adopting yields normalised from solar chemical properties reproduce Mn and Ni better, suggesting that there is still a lack of realistic theoretical yields of some iron-peak elements. The very low scatter (≈0.05 dex) in thin and thick disc sequences could provide an observational constrain for Galactic evolutionary models that study the efficiency of stellar radial migration.
Context. Large grids of synthetic spectra covering a wide range of stellar parameters are essential tools for different stellar and (extra-) Galactic physical applications. They can be used for the ...automatic parametrisation of stellar spectra such as that performed by the AMBRE project whose main goal is to determine the stellar atmospheric parameters of a few hundred thousands of archived spectra of four ESO spectrographs. Aims. To fulfil the needs of AMBRE and similar future projects, we computed a grid of synthetic spectra over the whole optical domain for cool to very cool stars of any luminosity (from dwarfs to supergiants) with metallicities varying from 10-5 to 10 times the solar metallicity, and considering large variations in the chemical composition of the α-elements. Methods. In these spectrum computations, we used new generation MARCS model atmospheres and the Turbospectrum code for radiative transfer. We also took into account atomic and molecular linelists that were as complete as possible and adopted, in the spectral synthesis, the same physical assumptions and input data as in the MARCS models. This allowed us to present a grid in which there is a high consistency between the atmosphere models and the synthetic spectra. Results. We present a new grid of 16 783 high resolution spectra over the wavelength range 3000 Å to 12 000 Å computed at a spectral resolution higher than 150 000. Normalised and absolute flux versions are available over a wide range of stellar atmospheric parameters for stars of FGKM spectral types. The parameters covered are 2500 K ≤ Teff ≤ 8000 K, −0.5 ≤ log(g) ≤ 5.5 dex, and −5.0 ≤ M/H ≤ + 1.0 dex. Moreover, for each combination of these stellar parameters, five different values of the enrichment in α-elements were considered (0.0, ± 0.2 dex and ± 0.4 dex around the standard values). This library is thus relevant to any stellar type and luminosity class, present in old and intermediate-age stellar populations with chemical composition varying from extremely metal-poor to metal-rich. This grid is made publicly available through the POLLUX database (about 50% of the spectra have been included in this database) and in FITS format upon request to the authors.
According to our current cosmological model, galaxies like the Milky Way are expected to experience many mergers over their lifetimes. The most massive of the merging galaxies will be dragged towards ...the disc plane, depositing stars and dark matter into an accreted disc structure. In this work, we utilize the chemodynamical template developed in Ruchti et al. to hunt for accreted stars. We apply the template to a sample of 4675 stars in the third internal data release from the Gaia-ESO Spectroscopic Survey. We find a significant component of accreted halo stars, but find no evidence of an accreted disc component. This suggests that the Milky Way has had a rather quiescent merger history since its disc formed some 8–10 billion years ago and therefore possesses no significant dark matter disc.
Gaia and its complementary spectroscopic surveys combined will yield the most comprehensive database of kinematic and chemical information of stars in the Milky Way. The Gaia FGK benchmark stars play ...a central role in this matter as they are calibration pillars for the atmospheric parameters and chemical abundances for various surveys. The spectroscopic analyses of the benchmark stars are done by combining different methods, and the results will be affected by the systematic uncertainties inherent in each method. In this paper, we explore some of these systematic uncertainties. We determined line abundances of Ca, Cr, Mn and Co for four benchmark stars using six different methods. We changed the default input parameters of the different codes in a systematic way and found, in some cases, significant differences between the results. Since there is no consensus on the correct values for many of these default parameters, we urge the community to raise discussions towards standard input parameters that could alleviate the difference in abundances obtained by different methods. In this work, we provide quantitative estimates of uncertainties in elemental abundances due to the effect of differing technical assumptions in spectrum modelling.
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