We explore the structure of the element abundance-age-orbit distribution of the stars in the Milky Way's low- disk, by (re-)deriving precise Fe/H, X/Fe, and ages, along with orbits, for red clump ...stars from the apogee survey. There has been a long-standing theoretical expectation and observational evidence that metallicity (Fe/H) and age are informative about a star's orbit, e.g., about its angular momentum and the corresponding mean Galactocentric distance or its vertical motion. Indeed, our analysis of the apogee data confirms that Fe/H or age alone can predict the stars' orbits far less well than a combination of the two. Remarkably, we find and show explicitly that, for known Fe/H and age, the other abundances X/Fe of Galactic disk stars can be predicted well (on average to 0.02 dex) across a wide range of Galactocentric radii, and therefore provide little additional information, e.g., for predicting their orbit. While the age-abundance space for metal-poor stars and potentially for stars near the Galactic center is rich or complex, for the bulk of the Galaxy's low- disk it is simple: Fe/H and age contain most information, unless X/Fe can be measured to 0.02 or better. Consequently, we do not have the precision with current (and likely near-future) data to assign stars to their individual (coeval) birth clusters, from which the disk is presumably formed. We can, however, place strong constraints on future models of Galactic evolution, chemical enrichment, and mixing.
Abstract
The surroundings of massive protostars constitute an accretion disc which has numerically been shown to be subject to fragmentation and responsible for luminous accretion-driven outbursts. ...Moreover, it is suspected to produce close binary companions which will later strongly influence the star's future evolution in the Hertzsprung–Russel diagram. We present three-dimensional gravitation-radiation-hydrodynamic numerical simulations of 100 M⊙ pre-stellar cores. We find that accretion discs of young massive stars violently fragment without preventing the (highly variable) accretion of gaseous clumps on to the protostars. While acquiring the characteristics of a nascent low-mass companion, some disc fragments migrate on to the central massive protostar with dynamical properties showing that its final Keplerian orbit is close enough to constitute a close massive protobinary system, having a young high- and a low-mass components. We conclude on the viability of the disc fragmentation channel for the formation of such short-period binaries, and that both processes – close massive binary formation and accretion bursts – may happen at the same time. FU-Orionis-type bursts, such as observed in the young high-mass star S255IR−NIRS3, may not only indicate ongoing disc fragmentation, but also be considered as a tracer for the formation of close massive binaries – progenitors of the subsequent massive spectroscopic binaries – once the high-mass component of the system will enter the main-sequence phase of its evolution. Finally, we investigate the Atacama Large (sub-)Millimeter Array observability of the disc fragments.
Macrophages are key orchestrators of the inflammatory and repair responses in the lung, and the diversity of their function is indicated by their polarized states and distinct subpopulations and ...localization in the lung. Here, we characterized the pulmonary macrophage populations in the interstitial and alveolar compartments during the induction and resolution of acute lung injury induced by Pseudomonas aeruginosa infection. We identified macrophage subpopulations and polarity according to FACS analysis of cell surface protein markers, combined with cell sorting for gene expression using real-time PCR. With these techniques, we validated a novel, alternatively activated (M2) marker (transferrin receptor), and we described three interstitial and alveolar macrophage subpopulations in the lung whose distribution and functional state evolved from the induction to resolution phases of lung injury. Together, these findings indicate the presence and evolution of distinct macrophage subsets in the lung that serve specific niches in regulating the inflammatory response and its resolution. Alterations in the balance and function of these subpopulations could lead to nonresolving acute lung injury.
We use the Bullock & Johnston suite of simulations to study the density profiles of L*-type galaxy stellar halos. Observations of the Milky Way and M31 stellar halos show contrasting results: the ...Milky Way has a "broken" profile, where the density falls off more rapidly beyond ~25 kpc, while M31 has a smooth profile out to 100 kpc with no obvious break. Simulated stellar halos, built solely by the accretion of dwarf galaxies, also exhibit this behavior: some halos have breaks, while others do not. The presence or absence of a break in the stellar halo profile can be related to the accretion history of the galaxy. We find that a break radius is strongly related to the buildup of stars at apocenters. We relate these findings to observations, and find that the "break" in the Milky Way density profile is likely associated with a relatively early (~6-9 Gyr ago) and massive accretion event. In contrast, the absence of a break in the M31 stellar halo profile suggests that its accreted satellites have a wide range of apocenters. Hence, it is likely that M31 has had a much more prolonged accretion history than the Milky Way.
Diabet. Med. 27, 391–397 (2010)
Aims Diets rich in non‐viscous fibre are linked to a reduced risk of both diabetes and cardiovascular disease; however, the mechanism of action remains unclear. This ...study was undertaken to assess whether chronic consumption of this type of fibre in individuals with the metabolic syndrome would improve insulin sensitivity via changes in ectopic fat storage.
Methods The study was a single‐blind, randomized, parallel nutritional intervention where 20 insulin resistant subjects consumed either the fibre supplement (resistant starch) (40 g/day) or placebo supplement (0 g/day) for 12 weeks. Insulin sensitivity was measured by euglycaemic–hyperinsulinaemic clamp and ectopic fat storage measured by whole‐body magnetic resonance spectroscopy.
Results Resistant starch consumption did not significantly affect body weight, fat storage in muscle, liver or visceral depots. There was also no change with resistant starch feeding on vascular function or markers of inflammation. However, in subjects randomized to consume the resistant starch, insulin sensitivity improved compared with the placebo group (P = 0.023). Insulin sensitivity correlated significantly with changes in waist circumference and fat storage in tibialis muscle and to a lesser extent to visceral‐to‐subcutaneous abdominal adipose tissue ratio.
Conclusion Consumption of resistant starch improves insulin sensitivity in subjects with the metabolic syndrome. Unlike in animal models, diabetes prevention does not appear to be directly related to changes in body adiposity, blood lipids or inflammatory markers. Further research to elucidate the mechanisms behind this change in insulin sensitivity in human subjects is required.
We study the fragmentation of the nearest high line-mass filament, the integral shaped filament (ISF, line-mass ~400 M⊙ pc-1) in the Orion A molecular cloud. We have observed a 1.6 pc long section of ...the ISF with the Atacama Large Millimetre/submillimeter Array (ALMA) at 3 mm continuum emission, at a resolution of ~3″ (1200 AU). We identify from the region 43 dense cores with masses about a solar mass. 60% of the ALMA cores are protostellar and 40% are starless. The nearest neighbour separations of the cores do not show a preferred fragmentation scale; the frequency of short separations increases down to 1200 AU. We apply a two-point correlation analysis on the dense core separations and show that the ALMA cores are significantly grouped at separations below ~17 000 AU and strongly grouped below ~6000 AU. The protostellar and starless cores are grouped differently: only the starless cores group strongly below ~6000 AU. In addition, the spatial distribution of the cores indicates periodic grouping of the cores into groups of ~30 000 AU in size, separated by ~50 000 AU. The groups coincide with dust column density peaks detected by Herschel. These results show hierarchical, two-mode fragmentation in which the maternal filament periodically fragments into groups of dense cores. Critically, our results indicate that the fragmentation models for lower line-mass filaments (~16 M⊙ pc-1) fail to capture the observed properties of the ISF. We also find that the protostars identified with Spitzer and Herschel in the ISF are grouped at separations below ~17 000 AU. In contrast, young stars with disks do not show significant grouping. This suggests that the grouping of dense cores is partially retained over the protostar lifetime, but not over the lifetime of stars with disks. This is in agreement with a scenario where protostars are ejected from the maternal filament by the slingshot mechanism, a model recently proposed for the ISF. The separation distributions of the dense cores and protostars may also provide an evolutionary tracer of filament fragmentation.
For managing overactive bladder (OAB), mirabegron, a β3 adrenergic receptor agonist, is typically used as second-line pharmacotherapy after antimuscarinics. Therefore, patients initiating treatment ...with mirabegron and antimuscarinics may differ, potentially impacting associated clinical outcomes. When using observational data to evaluate real-world safety and effectiveness of OAB treatments, residual bias due to unmeasured confounding and/or confounding by indication are important considerations. Falsification analysis, in which clinically irrelevant endpoints are tested as a reference, can be used to assess residual bias. The objective in this study was to compare baseline cardiovascular risk among OAB patients by treatment, and assess the presence of residual bias via falsification analysis of OAB patients treated with mirabegron or antimuscarinics, to determine whether clinically relevant comparisons across groups would be feasible. Linked electronic health record and claims data (Optum/Humedica) for OAB patients in the United States from 2011-2015 were available, with index defined as first date of OAB treatment during this period. Unadjusted characteristics were compared across groups at index and propensity-matching conducted. Falsification endpoints (hepatitis C, shingles, community-acquired pneumonia) were compared between groups using odds ratios (ORs) and 95% confidence intervals (CI). The study identified 10,311 antimuscarinic- and 408 mirabegron-treated patients. Mirabegron patients were predominantly older males, with more comorbidities. The analytic sample included 1,188 antimuscarinic patients propensity-matched to 396 mirabegron patients; after matching, no significant baseline differences remained. Estimates of falsification ORs were 0.7 (CI:0.3-1.7) for shingles, 1.5 (CI:0.3-8.2) for hepatitis C, 0.8 (CI:0.4-1.8) and 0.9 (CI:0.6-1.4) for pneumonia. While propensity matching successfully balanced observed covariates, wide CIs prevented definitive conclusions regarding residual bias. Accordingly, further observational comparisons by treatment group were not pursued. In real-world analysis, bias-detection methods could not confirm that differences in cardiovascular risk in patients receiving mirabegron versus antimuscarinics were fully adjusted for, precluding clinically relevant comparisons across treatment groups.
Context. Filamentary structures in the interstellar medium are crucial ingredients of the star formation process. They fragment to form individual star-forming cores, and at the same time they may ...also funnel gas toward the central gas cores, providing an additional gas reservoir. Aims. We want to resolve the length scales for filament formation and fragmentation (resolution ≤0.1 pc), in particular the Jeans length and cylinder fragmentation scale. Methods. We have observed the prototypical high-mass star-forming filament IRDC 18223 with the Plateau de Bure Interferometer (PdBI) in the 3.2 mm continuum and N2H+(1–0) line emission in a ten-field mosaic at a spatial resolution of ~ 4′′ (~14 000 au). Results. The dust continuum emission resolves the filament into a chain of at least 12 relatively regularly spaced cores. The mean separation between cores is ~0.40(± 0.18) pc. While this is approximately consistent with the fragmentation of an infinite, isothermal, and gravitationally bound gas cylinder, a high mass-to-length ratio of M/l ≈ 1000 M⊙ pc-1 requires additional turbulent and/or magnetic support against radial collapse of the filament. The N2H+(1−0) data reveal a velocity gradient perpendicular to the main filament. Although rotation of the filament cannot be excluded, the data are also consistent with the main filament being comprised of several velocity-coherent subfilaments. Furthermore, this velocity gradient perpendicular to the filament resembles results toward Serpens south that are interpreted as signatures of filament formation within magnetized and turbulent sheet-like structures. Lower-density gas tracers (CI and C18O) reveal a similar red- and blueshifted velocity structure on scales around 60′′ east and west of the filament. This may tentatively be interpreted as a signature of the large-scale cloud and the smaller scale filament being kinematically coupled. We do not identify a velocity gradient along the axis of the filament. This may be due to no significant gas flows along the filamentary axis, but it may also be partly caused by a low inclination angle of the filament with respect to the plane of the sky minimizing such a signature. Conclusions. The IRDC 18223 3.2 mm continuum data are consistent with thermal fragmentation of a gravitationally bound and compressible gas cylinder. However, the high mass-to-length ratio requires additional support – most likely turbulence and/or magnetic fields – against collapse. The N2H+ spectral line data indicate a kinematic origin of the filament, but we cannot conclusively differentiate whether it has formed out of (pre-existing) velocity-coherent subfilaments, whether magnetized converging gas flows, a larger-scale collapsing cloud, or even whether rotation played a significant role during filament formation.
The immunology of food allergy Johnston, Laura K; Chien, Karen B; Bryce, Paul J
The Journal of immunology (1950),
2014-Mar-15, 2014-03-15, 20140315, Letnik:
192, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Food allergies represent an increasingly prevalent human health problem, and therapeutic options remain limited, with avoidance being mainstay, despite its adverse effects on quality of life. A ...better understanding of the key immunological mechanisms involved in such responses likely will be vital for development of new therapies. This review outlines the current understanding of how the immune system is thought to contribute to prevention or development of food allergies. Drawing from animal studies, as well as clinical data when available, the importance of oral tolerance in sustaining immunological nonresponsiveness to food Ags, our current understanding of why oral tolerance may fail and sensitization may occur, and the knowledge of pathways that may lead to anaphylaxis and food allergy-associated responses are addressed.
ABSTRACT
Interactions between galaxies leave distinguishable imprints in the form of tidal features, which hold important clues about their mass assembly. Unfortunately, these structures are ...difficult to detect because they are low surface brightness features, so deep observations are needed. Upcoming surveys promise several orders of magnitude increase in depth and sky coverage, for which automated methods for tidal feature detection will become mandatory. We test the ability of a convolutional neural network to reproduce human visual classifications for tidal detections. We use as training ∼6000 simulated images classified by professional astronomers. The mock Hyper Suprime Cam Subaru (HSC) images include variations with redshift, projection angle, and surface brightness (μlim = 26–35 mag arcsec−2). We obtain satisfactory results with accuracy, precision, and recall values of Acc = 0.84, P = 0.72, and R = 0.85 for the test sample. While the accuracy and precision values are roughly constant for all surface brightness, the recall (completeness) is significantly affected by image depth. The recovery rate shows strong dependence on the type of tidal features: we recover all the images showing shell features and 87 per cent of the tidal streams; these fractions are below 75 per cent for mergers, tidal tails, and bridges. When applied to real HSC images, the performance of the model worsens significantly. We speculate that this is due to the lack of realism of the simulations, and take it as a warning on applying deep learning models to different data domains without prior testing on the actual data.
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