Low-mass pre--main-sequence stars in the Magellanic Clouds

[Abridged] The stellar Initial Mass Function (IMF) suggests that sub-solar stars form in very large numbers. Most attractive places for catching low-mass star formation in the act are young stellar clusters and associations, still (half-)embedded in star-forming regions. The low-mass stars in such regions are still in their pre--main-sequence (PMS) evolutionary phase. The peculiar nature of these objects and the contamination of their samples by the evolved populations of the Galactic disk impose demanding observational techniques for the detection of complete numbers of PMS stars in the Milky Way. The Magellanic Clouds, the companion galaxies to our own, demonstrate an exceptional star formation activity. The low extinction and stellar field contamination in star-forming regions of these galaxies imply a more efficient detection of low-mass PMS stars than in the Milky Way, but their distance from us make the application of special detection techniques unfeasible. Nonetheless, imaging with the Hubble Space Telescope yield the discovery of solar and sub-solar PMS stars in the Magellanic Clouds from photometry alone. Unprecedented numbers of such objects are identified as the low-mass stellar content of their star-forming regions, changing completely our picture of young stellar systems outside the Milky Way, and extending the extragalactic stellar IMF below the persisting threshold of a few solar masses. This review presents the recent developments in the investigation of PMS stars in the Magellanic Clouds, with special focus on the limitations by single-epoch photometry that can only be circumvented by the detailed study of the observable behavior of these stars in the color-magnitude diagram. The achieved characterization of the low-mass PMS stars in the Magellanic Clouds allowed thus a more comprehensive understanding of the star formation process in our neighboring galaxies.Comment: Review paper, 26 pages (in LaTeX style for Springer journals), 4 figures. Accepted for publication in Space Science Review

Bypassing the nearest emergency department for a more distant neurosurgical centre in traumatic brain injury patients

Background and objective Major trauma triage within regional trauma networks (RTN) select patients with suspected TBI for bypass to specialist neuroscience centres (SNC), expediting neurosurgical care but may delay resuscitation. This comparative effectiveness study assessed the impact of this strategy on the risk adjusted hospital survival rates of patients confirmed to have intracranial injury on brain computed tomography (CT) scan. Method A retrospective cohort study was conducted using Trauma Audit and Research Network trauma registry data. Adult patients with a TBI on CT scan were included if they presented between June 2015 to February 2016 to SNCs or non-specialist acute hospitals (NSAH) in the North of England (South Cumbria, Lancashire and the North East Region). Patients were identified as having bypassed a nearer NSAH emergency department (ED) to a SNC using google maps. Their standardised excess survival rate was compared to TBI patients who received primary treatment at a NSAH. A multivariate logistic regression model predicting 30-day survival after TBI (Ps14n) 1 was used to adjust for variation in casemix between cohorts. Study design and results 355 patients met the study inclusion criteria, with 89/355 (25%) of TBI patients bypassing a nearer NSAH to a SNC, and 266/355 (75%) receiving primary treatment at an NSAH. The median severity of intracranial injury was equivalent (median Head Abbreviated Injury Scale 4 (IQR 4–5) in each group. There was no statistically significant difference in the standardised excess survival rate between the two cohorts; +6.15% for bypass (95% CI −1.24% to +13.55%) versus −1.12% for non-bypass (95% CI −4.51% to +2.25%). Conclusion and future research No statistically significant survival benefit was identified for TBI patients who bypassed the nearest ED to attend a SNC compared to those receiving treatment at the nearest NSAH, however a clinically significant 7% excess survival rate merits a larger study

Enterovirus exposure uniquely discriminates type 1 diabetes patients with a homozygous from a heterozygous melanoma differentiation-associated protein 5/interferon induced with helicase C domain 1A946T genotype

In children at risk for type 1 diabetes, innate immune activity is detected before seroconversion. Enterovirus infections have been linked to diabetes development, and a polymorphism (A946T) in the innate immune sensor recognizing enterovirus RNA, interferon-induced with helicase C domain 1/melanoma differentiation-associated protein 5, predisposes to disease. We hypothesized that the strength of innate antienteroviral responses is affected in autoimmune type 1 diabetes patients and linked to the A946T polymorphism. We compared induction of interferon-stimulated genes (ISGs) in peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs) in healthy individuals and diabetes patients upon stimulation with enterovirus, enterovirus-antibody complexes, or ligands mimicking infection in relation to the A946T polymorphism. Overall, PBMCs of diabetes patients and healthy donors showed comparable ISG induction upon stimulation. No differences were observed in DCs. Interestingly, the data imply that the magnitude of responses to enterovirus and enterovirus-antibody complexes in PBMCs is critically influenced by the A946T polymorphism and elevated in heterozygotes compared to TT homozygous individuals in autoimmune diabetes patients, but not healthy controls. These data imply an intrinsic difference in the responses to enterovirus and enterovirus-antibody complexes in diabetes patients carrying a TT risk genotype compared to heterozygotes that may influence control of enterovirus clearanc