35 research outputs found

    Jeans modelling of the Milky Way's nuclear stellar disc

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    The nuclear stellar disc (NSD) is a flattened stellar structure that dominates the gravitational potential of the Milky Way at Galactocentric radii 30ā‰²Rā‰²300pcā . In this paper, we construct axisymmetric Jeans dynamical models of the NSD based on previous photometric studies and we fit them to line-of-sight kinematic data of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and silicon monoxide (SiO) maser stars. We find that (i) the NSD mass is lower but consistent with the mass independently determined from photometry by Launhardt et al. Our fiducial model has a mass contained within spherical radius r=100pc of M(r 1. Observations and theoretical models of the star-forming molecular gas in the central molecular zone suggest that large vertical oscillations may be already imprinted at stellar birth. However, the finding Ļƒz/ĻƒR > 1 depends on a drop in the velocity dispersion in the innermost few tens of parsecs, on our assumption that the NSD is axisymmetric, and that the available (extinction corrected) stellar samples broadly trace the underlying light and mass distributions, all of which need to be established by future observations and/or modelling. (iii) We provide the most accurate rotation curve to date for the innermost 500pc of our Galaxy

    ALMA Uncovers Highly Filamentary Structure toward the Sgr E Region

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    We report on the discovery of linear filaments observed in the CO(1-0) emission for a āˆ¼2ā€² field of view toward the Sgr E star-forming region, centered at (l, b) = (358.Ā°720, 0.Ā°011). The Sgr E region is thought to be at the turbulent intersection of the ā€œfar dust laneā€ associated with the Galactic bar and the Central Molecular Zone (CMZ). This region is subject to strong accelerations, which are generally thought to inhibit star formation, yet Sgr E contains a large number of H ii regions. We present 12CO(1-0), 13CO(1-0), and C18O(1-0) spectral line observations from the Atacama Large Millimeter/submillimeter Array and provide measurements of the physical and kinematic properties for two of the brightest filaments. These filaments have widths (FWHMs) of āˆ¼0.1 pc and are oriented nearly parallel to the Galactic plane, with angles from the Galactic plane of āˆ¼2Ā°. The filaments are elongated, with lower-limit aspect ratios of āˆ¼5:1. For both filaments, we detect two distinct velocity components that are separated by about 15 km sāˆ’1. In the C18O spectral line data, with āˆ¼0.09 pc spatial resolution, we find that these velocity components have relatively narrow (āˆ¼1-2 km sāˆ’1) FWHM line widths when compared to other sources toward the Galactic center. The properties of these filaments suggest that the gas in the Sgr E complex is being ā€œstretched,ā€ as it is rapidly accelerated by the gravitational field of the Galactic bar while falling toward the CMZ, a result that could provide insights into the extreme environment surrounding this region and the large-scale processes that fuel this environment

    Adjuvant mitotane versus surveillance in low-grade, localised adrenocortical carcinoma (ADIUVO): an international, multicentre, open-label, randomised, phase 3 trial and observational study

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    BACKGROUND: Adjuvant treatment with mitotane is commonly used after resection of adrenocortical carcinoma; however, treatment remains controversial, particularly if risk of recurrence is not high. We aimed to assess the efficacy and safety of adjuvant mitotane compared with surveillance alone following complete tumour resection in patients with adrenocortical carcinoma considered to be at low to intermediate risk of recurrence. METHODS: ADIUVO was a multicentre, open-label, parallel, randomised, phase 3 trial done in 23 centres across seven countries. Patients aged 18 years or older with adrenocortical carcinoma and low to intermediate risk of recurrence (R0, stage I-III, and Ki67 ā‰¤10%) were randomly assigned to adjuvant oral mitotane two or three times daily (the dose was adjusted by the local investigator with the target of reaching and maintaining plasma mitotane concentrations of 14-20 mg/L) for 2 years or surveillance alone. All consecutive patients at 14 study centres fulfilling the eligibility criteria of the ADIUVO trial who refused randomisation and agreed on data collection via the European Network for the Study of Adrenal Tumors adrenocortical carcinoma registry were included prospectively in the ADIUVO Observational study. The primary endpoint was recurrence-free survival, defined as the time from randomisation to the first radiological evidence of recurrence or death from any cause (whichever occurred first), assessed in all randomly assigned patients by intention to treat. Overall survival, defined as time from the date of randomisation to the date of death from any cause, was a secondary endpoint analysed by intention to treat in all randomly assigned patients. Safety was assessed in all patients who adhered to the assigned regimen, which was defined by taking at least one tablet of mitotane in the mitotane group and no mitotane at all in the surveillance group. The ADIUVO trial is registered with ClinicalTrials.gov, NCT00777244, and is now complete. FINDINGS: Between Oct 23, 2008, and Dec 27, 2018, 45 patients were randomly assigned to mitotane and 46 to surveillance alone. Because the study was discontinued prematurely, 5-year recurrence-free and overall survival are reported instead of recurrence-free and overall survival as defined in the protocol. 5-year recurrence-free survival was 79% (95% CI 67-94) in the mitotane group and 75% (63-90) in the surveillance group (hazard ratio 0Ā·74 [95% CI 0Ā·30-1Ā·85]). Two people in the mitotane group and five people in the surveillance group died, and 5-year overall survival was not significantly different (95% [95% CI 89-100] in the mitotane group and 86% [74-100] in the surveillance group). All 42 patients who received mitotane had adverse events, and eight (19%) discontinued treatment. There were no grade 4 adverse events or treatment-related deaths. INTERPRETATION: Adjuvant mitotane might not be indicated in patients with low-grade, localised adrenocortical carcinoma considering the relatively good prognosis of these patients, and no significant improvement in recurrence-free survival and treatment-associated toxicity in the mitotane group. However, the study was discontinued prematurely due to slow recruitment and cannot rule out an efficacy of treatment. FUNDING: AIFA, ENSAT Cancer Health F2-2010-259735 programme, Deutsche Forschungsgemeinschaft, Cancer Research UK, and the French Ministry of Health

    Kinematics of Galactic Centre clouds shaped by shear-seeded solenoidal turbulence

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    The Central Molecular Zone (CMZ; the central āˆ¼500 pc of the Galaxy) is a kinematically unusual environment relative to the Galactic disc, with high velocity dispersions and a steep size-linewidth relation of the molecular clouds. In addition, the CMZ region has a significantly lower star formation rate (SFR) than expected by its large amount of dense gas. An important factor in explaining the low SFR is the turbulent state of the star-forming gas, which seems to be dominated by rotational modes. However, the turbulence driving mechanism remains unclear. In this work, we investigate how the Galactic gravitational potential affects the turbulence in CMZ clouds. We focus on the CMZ cloud G0.253+0.016 (ā€˜the Brickā€™), which is very quiescent and unlikely to be kinematically dominated by stellar feedback. We demonstrate that several kinematic properties of the Brick arise naturally in a cloud-scale hydrodynamics simulation that takes into account the Galactic gravitational potential. These properties include the line-of-sight velocity distribution, the steepened size-linewidth relation, and the predominantly solenoidal nature of the turbulence. Within the simulation, these properties result from the Galactic shear in combination with the cloudā€™s gravitational collapse. This is a strong indication that the Galactic gravitational potential plays a crucial role in shaping the CMZ gas kinematics, and is a major contributor to suppressing the SFR by inducing predominantly solenoidal turbulent modes

    Effect of personal exposure to black carbon on changes in allergic asthma gene methylation measured 5 days later in urban children: importance of allergic sensitization

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    Background Asthma gene DNA methylation may underlie the effects of air pollution on airway inflammation. However, the temporality and individual susceptibility to environmental epigenetic regulation of asthma has not been fully elucidated. Our objective was to determine the timeline of black carbon (BC) exposure, measured by personal sampling, on DNA methylation of allergic asthma genes 5 days later to capture usual weather variations and differences related to changes in behavior and activities. We also sought to determine how methylation may vary by seroatopy and cockroach sensitization and by elevated fractional exhaled nitric oxide (FeNO). Methods Personal BC levels were measured during two 24-h periods over a 6-day sampling period in 163 New York City children (age 9ā€“14 years), repeated 6 months later. During home visits, buccal cells were collected as noninvasive surrogates for lower airway epithelial cells and FeNO measured as an indicator of airway inflammation. CpG promoter loci of allergic asthma genes (e.g., interleukin 4 (IL4), interferon gamma (IFNĪ³), inducible nitric oxide synthase (NOS2A)), arginase 2 (ARG2)) were pyrosequenced at the start and end of each sampling period. Results Higher levels of BC were associated with lower methylation of IL4 promoter CpGāˆ’48 5 days later. The magnitude of association between BC exposure and demethylation of IL4 CpGāˆ’48 and NOS2A CpG+5099 measured 5 days later appeared to be greater among seroatopic children, especially those sensitized to cockroach allergens (RR [95% CI] 0.55 [0.37ā€“0.82] and 0.67 [0.45ā€“0.98] for IL4 CpGāˆ’48 and NOS2A CpG+5099, respectively), compared to non-sensitized children (RR [95% CI] 0.87 [0.65ā€“1.17] and 0.95 [0.69ā€“1.33] for IL4 CpGāˆ’48 and NOS2A CpG+5099, respectively); however, the difference was not statistically different. In multivariable linear regression models, lower DNA methylation of IL4 CpGāˆ’48 and NOS2A CpG+5099 were associated with increased FeNO. Conclusions Our results suggest that exposure to BC may exert asthma proinflammatory gene demethylation 5 days later that in turn may link to airway inflammation. Our results further suggest that seroatopic children, especially those sensitized to cockroach allergens, may be more susceptible to the effect of acute BC exposure on epigenetic changes

    Autologous haematopoietic stem cell transplantation for treatment of multiple sclerosis

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    Autologous haematopoietic stem cell transplantation (AHSCT) is a multistep procedure that enables destruction of the immune system and its reconstitution from haematopoietic stem cells. Originally developed for the treatment of haematological malignancies, the procedure has been adapted for the treatment of severe immune-mediated disorders. Results from ~20 years of research make a compelling case for selective use of AHSCT in patients with highly active multiple sclerosis (MS), and for controlled trials. Immunological studies support the notion that AHSCT causes qualitative immune resetting, and have provided insight into the mechanisms that might underlie the powerful treatment effects that last well beyond recovery of immune cell numbers. Indeed, studies have demonstrated that AHSCT can entirely suppress MS disease activity for 4ā€“5 years in 70ā€“80% of patients, a rate that is higher than those achieved with any other therapies for MS. Treatment-related mortality, which was 3.6% in studies before 2005, has decreased to 0.3% in studies since 2005. Current evidence indicates that the patients who are most likely to benefit from and tolerate AHSCT are young, ambulatory and have inflammatory MS activity. Clinical trials are required to rigorously test the efficacy, safety and cost-effectiveness of AHSCT against highly active MS drugs

    PHANGS-JWST First Results: Stellar-feedback-driven Excitation and Dissociation of Molecular Gas in the Starburst Ring of NGC 1365?

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    We compare embedded young massive star clusters (YMCs) to (sub-)millimeter line observations tracing the excitation and dissociation of molecular gas in the starburst ring of NGC 1365. This galaxy hosts one of the strongest nuclear starbursts and richest populations of YMCs within 20 Mpc. Here we combine near-/mid-IR PHANGS-JWST imaging with new Atacama Large Millimeter/submillimeter Array multi-J CO (1-0, 2-1 and 4-3) and [C i] (1-0) mapping, which we use to trace CO excitation via R 42 = I CO(4āˆ’3)/I CO(2āˆ’1) and R 21 = I CO(2āˆ’1)/I CO(1āˆ’0) and dissociation via R CICO = I [CI](1āˆ’0)/I CO(2āˆ’1) at 330 pc resolution. We find that the gas flowing into the starburst ring from northeast to southwest appears strongly affected by stellar feedback, showing decreased excitation (lower R 42) and increased signatures of dissociation (higher R CICO) in the downstream regions. There, radiative-transfer modeling suggests that the molecular gas density decreases and temperature and [CI/CO] abundance ratio increase. We compare R 42 and R CICO with local conditions across the regions and find that both correlate with near-IR 2 Ī¼m emission tracing the YMCs and with both polycyclic aromatic hydrocarbon (11.3 Ī¼m) and dust continuum (21 Ī¼m) emission. In general, R CICO exhibits āˆ¼0.1 dex tighter correlations than R 42, suggesting C i to be a more sensitive tracer of changing physical conditions in the NGC 1365 starburst than CO (4-3). Our results are consistent with a scenario where gas flows into the two arm regions along the bar, becomes condensed/shocked, forms YMCs, and then these YMCs heat and dissociate the gas

    PHANGS-JWST First Results: Multiwavelength View of Feedback-driven Bubbles (the Phantom Voids) across NGC 628

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    We present a high-resolution view of bubbles within the Phantom Galaxy (NGC 628), a nearby (āˆ¼10 Mpc), star-forming (āˆ¼2 M āŠ™ yrāˆ’1), face-on (i āˆ¼ 9Ā°) grand-design spiral galaxy. With new data obtained as part of the Physics at High Angular resolution in Nearby GalaxieS (PHANGS)-JWST treasury program, we perform a detailed case study of two regions of interest, one of which contains the largest and most prominent bubble in the galaxy (the Phantom Void, over 1 kpc in diameter), and the other being a smaller region that may be the precursor to such a large bubble (the Precursor Phantom Void). When comparing to matched-resolution HĪ± observations from the Hubble Space Telescope, we see that the ionized gas is brightest in the shells of both bubbles, and is coincident with the youngest (āˆ¼1 Myr) and most massive (āˆ¼105 M āŠ™) stellar associations. We also find an older generation (āˆ¼20 Myr) of stellar associations is present within the bubble of the Phantom Void. From our kinematic analysis of the H I, H2 (CO), and H ii gas across the Phantom Void, we infer a high expansion speed of around 15 to 50 km sāˆ’1. The large size and high expansion speed of the Phantom Void suggest that the driving mechanism is sustained stellar feedback due to multiple mechanisms, where early feedback first cleared a bubble (as we observe now in the Precursor Phantom Void), and since then supernovae have been exploding within the cavity and have accelerated the shell. Finally, comparison to simulations shows a striking resemblance to our JWST observations, and suggests that such large-scale, stellar-feedback-driven bubbles should be common within other galaxies
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