69 research outputs found
Nebular Line Emission During the Epoch of Reionization
Nebular emission lines associated with galactic HII regions carry information
about both physical properties of the ionised gas and the source of ionising
photons as well as providing the opportunity of measuring accurate redshifts
and thus distances once a cosmological model is assumed. While nebular line
emission has been extensively studied at lower redshift there are currently
only few constraints within the epoch of reionisation (EoR, ), chiefly due
to the lack of sensitive near-IR spectrographs. However, this will soon change
with the arrival of the Webb Telescope providing sensitive near-IR spectroscopy
covering the rest-frame UV and optical emission of galaxies in the EoR. In
anticipation of Webb we combine the large cosmological hydrodynamical
simulation Bluetides with photoionisation modelling to predict the nebular
emission line properties of galaxies at . We find good agreement
with the, albeit limited, existing direct and indirect observational
constraints on equivalent widths though poorer agreement with luminosity
function constraints.Comment: 17 pages, accepted to MNRAS, significant modification from v1.0 data
available at https://stephenmwilkins.github.io/BluetidesEmissionLines_Public
Toivoa tulevaisuudesta: Kaunokirjalliset tulevaisuusvisiot
Keväällä 2020 järjestettiin Turun yliopistolla kurssi ”Toivoa tulevaisuudesta – Kaunokirjalliset tulevaisuusvisiot utopian kultakaudesta ilmastofiktioon”. Puheenvuoromme esittelee kurssin keskusteluista kummunneita keskeisiä näkökulmia
Finnish multiple sclerosis patients treated with cladribine tablets : a nationwide registry study
Background: Cladribine tablets for adult patients with highly active relapsing multiple sclerosis (MS) have been available in Finland since 2018. Real-world data from different genetic and geographical backgrounds are needed to complement data from clinical trials.Methods: We investigated the use of cladribine tablets in Finland in a non-interventional cohort study, based on real-world data from the nationwide Finnish MS registry. All eligible patients who had initiated treatment with cladribine tablets in 2018-2020 were included. Descriptive analyses for outcomes were conducted using summary statistics. Time-dependent endpoints were analyzed using cumulated events analysis based on 1-Kaplan-Meier estimates and curves. Subgroups were analyzed separately according to the number of previous disease-modifying therapies (DMTs) and the most common last preceding therapies.Results: Data of 179 patients were analyzed. Median follow-up time was 19.0 months (interquartile range [IQR] 12.0-26.2). Of the 134 patients who were followed for at least 12 months, 112 patients (83.6%) remained relapse-free during follow-up. Mean annualized relapse rate (ARR) was 1.0 (standard deviation [SD] 0.89) at baseline, and 0.1 (SD 0.30) at follow-up. Patients with two or more previous DMTs had shorter time to first relapse (median 2.5 months, IQR 0.6-9.3) when compared to patients with 0-1 previous DMTs (median 11.4 months, IQR 8.7-13.1) (p=0.013). After excluding patients switching from fingolimod (n=33), a statistically significant difference in time to first relapse was no longer observed between the two groups (p=0.252). Adverse events (AEs) were reported in 30 patients (16.8%). The most frequent AE was headache (n=14, 7.8%). One patient (0.6%) died of cardiac arrest. Discontinuation of cladribine tablets was reported in nine patients (5.0%).Conclusion: The mean ARR observed in this cohort was similar to what has been reported in clinical trials. Approximately half of the patients had used two or more previous DMTs before cladribine tablets. These patients had a shorter time to first relapse when compared to patients with 0-1 previous DMTs, mostly driven by early relapses in patients switching from fingolimod.Peer reviewe
The host galaxies of z=7 quasars: predictions from the BlueTides simulation
We examine the properties of the host galaxies of quasars using the
large volume, cosmological hydrodynamical simulation BlueTides. We find that
the 10 most massive black holes and the 191 quasars in the simulation (with
) are hosted by massive galaxies with
stellar masses , and , which have
large star formation rates, of and
, respectively. The hosts of the
most massive black holes and quasars in BlueTides are generally
bulge-dominated, with bulge-to-total mass ratio , however
their morphologies are not biased relative to the overall galaxy sample.
We find that the hosts of the most massive black holes and quasars are
significantly more compact, with half-mass radii kpc and kpc respectively; galaxies
with similar masses and luminosities have a wider range of sizes with a larger
median value, kpc. We make mock James
Webb Space Telescope (JWST) images of these quasars and their host galaxies. We
find that distinguishing the host from the quasar emission will be possible but
still challenging with JWST, due to the small sizes of quasar hosts. We find
that quasar samples are biased tracers of the intrinsic black hole--stellar
mass relation, following a relation that is 0.2 dex higher than that of the
full galaxy sample. Finally, we find that the most massive black holes and
quasars are more likely to be found in denser environments than the typical
black hole, indicating that minor mergers
play at least some role in growing black holes in the early Universe.Comment: 19 pages, 20 figures. Accepted for publication in MNRA
First Light And Reionisation Epoch Simulations (FLARES) : IV. The size evolution of galaxies at z ≥ 5
We present the intrinsic and observed sizes of galaxies at z >= 5 in the First Light And Reionisation Epoch Simulations (flares). We employ the large effective volume of flares to produce a sizeable sample of high-redshift galaxies with intrinsic and observed luminosities and half-light radii in a range of rest-frame ultraviolet (UV) and visual photometric bands. This sample contains a significant number of intrinsically ultracompact galaxies in the far-UV (1500 angstrom), leading to a negative intrinsic far-UV size-luminosity relation. However, after the inclusion of the effects of dust these same compact galaxies exhibit observed sizes that are as much as 50 times larger than those measured from the intrinsic emission, and broadly agree with a range of observational samples. This increase in size is driven by the concentration of dust in the core of galaxies, heavily attenuating the intrinsically brightest regions. At fixed luminosity we find a galaxy size redshift evolution with a slope of m = 1.21-1.87 depending on the luminosity sample in question, and we demonstrate the wavelength dependence of the size-luminosity relation that will soon be probed by the James Webb Space Telescope.Peer reviewe
First Light and Reionisation Epoch Simulations (FLARES) - VI. The colour evolution of galaxies z=5-15
With its exquisite sensitivity, wavelength coverage, and spatial and spectral resolution, the James Webb Space Telescope (JWST) is poised to revolutionize our view of the distant, high-redshift (z > 5) Universe. While Webb's spectroscopic observations will be transformative for the field, photometric observations play a key role in identifying distant objects and providing more comprehensive samples than accessible to spectroscopy alone. In addition to identifying objects, photometric observations can also be used to infer physical properties and thus be used to constrain galaxy formation models. However, inferred physical properties from broad-band photometric observations, particularly in the absence of spectroscopic redshifts, often have large uncertainties. With the development of new tools for forward modelling simulations, it is now routinely possible to predict observational quantities, enabling a direct comparison with observations. With this in mind, in this work, we make predictions for the colour evolution of galaxies at z = 5-15 using the First Light And Reionisation Epoch Simulations (flares) cosmological hydrodynamical simulation suite. We predict a complex evolution with time, driven predominantly by strong nebular line emission passing through individual bands. These predictions are in good agreement with existing constraints from Hubble and Spitzer as well as some of the first results from Webb. We also contrast our predictions with other models in the literature: While the general trends are similar, we find key differences, particularly in the strength of features associated with strong nebular line emission. This suggests photometric observations alone should provide useful discriminating power between different models and physical states of galaxies.Peer reviewe
Non-Cholesterol Sterol Levels Predict Hyperglycemia and Conversion to Type 2 Diabetes in Finnish Men
Peer reviewe
Indolepropionic acid and novel lipid metabolites are associated with a lower risk of type 2 diabetes in the Finnish Diabetes Prevention Study
Wide-scale profiling technologies including metabolomics broaden the possibility of novel discoveries related to the pathogenesis of type 2 diabetes (T2D). By applying non-targeted metabolomics approach, we investigated here whether serum metabolite profile predicts T2D in a well-characterized study population with impaired glucose tolerance by examining two groups of individuals who took part in the Finnish Diabetes Prevention Study (DPS); those who either early developed T2D (n = 96) or did not convert to T2D within the 15-year follow-up (n = 104). Several novel metabolites were associated with lower likelihood of developing T2D, including indole and lipid related metabolites. Higher indolepropionic acid was associated with reduced likelihood of T2D in the DPS. Interestingly, in those who remained free of T2D, indolepropionic acid and various lipid species were associated with better insulin secretion and sensitivity, respectively. Furthermore, these metabolites were negatively correlated with low-grade inflammation. We replicated the association between indolepropionic acid and T2D risk in one Finnish and one Swedish population. We suggest that indolepropionic acid, a gut microbiota-produced metabolite, is a potential biomarker for the development of T2D that may mediate its protective effect by preservation of alpha-cell function. Novel lipid metabolites associated with T2D may exert their effects partly through enhancing insulin sensitivity.Peer reviewe
First Light And Reionisation Epoch Simulations (FLARES) VIII. The Emergence of Passive Galaxies at
Passive galaxies are ubiquitous in the local universe, and various physical
channels have been proposed that lead to this passivity. To date, robust
passive galaxy candidates have been detected up to , but it is
still unknown if they exist at higher redshifts, what their relative abundances
are, and what causes them to stop forming stars. We present predictions from
the First Light And Reionisation Epoch Simulations (FLARES), a series of zoom
simulations of a range of overdensities using the EAGLE code. Passive galaxies
occur naturally in the EAGLE model at high redshift, and are in good agreement
with number density estimates from HST and early JWST results at . Due to the unique FLARES approach, we extend these predictions to
higher redshifts, finding passive galaxy populations up to . Feedback
from supermassive black holes is the main driver of passivity, leading to
reduced gas fractions and star forming gas reservoirs. We find that passive
galaxies at are not identified in the typical UVJ selection
space due to their still relatively young stellar populations, and present new
rest--frame selection regions. We also present NIRCam and MIRI fluxes, and find
that significant numbers of passive galaxies at should be
detectable in upcoming wide surveys with JWST. Finally, we present JWST colour
distributions, with new selection regions in the observer--frame for
identifying these early passive populations.Comment: 21 pages, 20 figures. Accepted to MNRA
Identification of the UBP1 Locus as a Critical Blood Pressure Determinant Using a Combination of Mouse and Human Genetics
Hypertension is a major health problem of largely unknown genetic origins. To identify new genes responsible for hypertension, genetic analysis of recombinant inbred strains of mice followed by human association studies might prove powerful and was exploited in our current study. Using a set of 27 recombinant BXD strains of mice we identified a quantitative trait locus (QTL) for blood pressure (BP) on distal chromosome 9. The association analysis of markers encompassing the syntenic region on human chromosome 3 gave in an additive genetic model the strongest association for rs17030583 C/T and rs2291897 G/A, located within the UBP1 locus, with systolic and diastolic BP (rs17030583: 1.3±0.4 mmHg p<0.001, 0.8±0.3 mmHg p = 0.006, respectively and rs2291897: 1.5±0.4 mmHg p<0.001, 0.8±0.3 mmHg p = 0.003, respectively) in three separate studies. Our study, which underscores the marked complementarities of mouse and human genetic approaches, identifies the UBP1 locus as a critical blood pressure determinant. UBP1 plays a role in cholesterol and steroid metabolism via the transcriptional activation of CYP11A, the rate-limiting enzyme in pregnenolone and aldosterone biosynthesis. We suggest that UBP1 and its functional partners are components of a network controlling blood pressure
- …