1,057 research outputs found
Polygenic transcriptome risk scores (PTRS) can improve portability of polygenic risk scores across ancestries
Background: Polygenic risk scores (PRS) are valuable to translate the results of genome-wide association studies (GWAS) into clinical practice. To date, most GWAS have been based on individuals of European-ancestry leading to poor performance in populations of non-European ancestry. Results: We introduce the polygenic transcriptome risk score (PTRS), which is based on predicted transcript levels (rather than SNPs), and explore the portability of PTRS across populations using UK Biobank data. Conclusions: We show that PTRS has a significantly higher portability (Wilcoxon p=0.013) in the African-descent samples where the loss of performance is most acute with better performance than PRS when used in combination
The nature of the SDSS galaxies in various classes based on morphology, colour and spectral features -- I. Optical properties
We present a comprehensive study of the nature of the SDSS galaxies divided
into various classes based on their morphology, colour, and spectral features.
The SDSS galaxies are classified into early-type and late-type; red and blue;
passive, HII, Seyfert, and LINER, returning a total of 16 fine classes of
galaxies. We examine the luminosity dependence of seven physical parameters of
galaxies in each class. We find that more than half of red early-type galaxies
(REGs) have star formation or AGN activity, and that these active REGs have
smaller axis ratio and bluer outside compared to the passive REGs. Blue
early-type galaxies (BEGs) show structural features similar to those of REGs,
but their centres are bluer than REGs. HII BEGs are found to have bluer centres
than passive BEGs, but HII REGs have bluer outside than passive REGs.
Bulge-dominated late-type galaxies have red colours. Passive red late-types are
similar to REGs in several aspects. Most blue late-type galaxies (BLGs) have
forming stars, but a small fraction of BLGs do not show evidence for current
star formation activity. Differences of other physical parameters among
different classes are inspected, and their implication on galaxy evolution is
discussed.Comment: 16 pages, 10 tables, 16 figures; accepted for publication in MNRA
Epigenetic regulation of cyclooxygenase-2 by methylation of c8orf4 in pulmonary fibrosis
Fibroblasts derived from the lungs of patients with idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc) produce low levels of prostaglandin (PG) E(2), due to a limited capacity to up-regulate cyclooxygenase-2 (COX-2). This deficiency contributes functionally to the fibroproliferative state, however the mechanisms responsible are incompletely understood. In the present study, we examined whether the reduced level of COX-2 mRNA expression observed in fibrotic lung fibroblasts is regulated epigenetically. The DNA methylation inhibitor, 5-aza-2′-deoxycytidine (5AZA) restored COX-2 mRNA expression by fibrotic lung fibroblasts dose dependently. Functionally, this resulted in normalization of fibroblast phenotype in terms of PGE(2) production, collagen mRNA expression and sensitivity to apoptosis. COX-2 methylation assessed by bisulfite sequencing and methylation microarrays was not different in fibrotic fibroblasts compared with controls. However, further analysis of the methylation array data identified a transcriptional regulator, chromosome 8 open reading frame 4 (thyroid cancer protein 1, TC-1) (c8orf4), which is hypermethylated and down-regulated in fibrotic fibroblasts compared with controls. siRNA knockdown of c8orf4 in control fibroblasts down-regulated COX-2 and PGE(2) production generating a phenotype similar to that observed in fibrotic lung fibroblasts. Chromatin immunoprecipitation demonstrated that c8orf4 regulates COX-2 expression in lung fibroblasts through binding of the proximal promoter. We conclude that the decreased capacity of fibrotic lung fibroblasts to up-regulate COX-2 expression and COX-2-derived PGE(2) synthesis is due to an indirect epigenetic mechanism involving hypermethylation of the transcriptional regulator, c8orf4
A pilot telephone intervention to increase uptake of breast cancer screening in socially deprived areas in Scotland (TELBRECS):study protocol for a randomised controlled trial
BACKGROUND Breast cancer accounts for almost 30% of all cancers and is the second leading cause of cancer deaths in women in Scotland. Screening is key to early detection. The Scottish Breast Screening Programme is a nationwide, free at point of delivery screening service, to which all women aged between 50 and 70 years are invited to attend every 3 years. Currently over three-quarters of invited women regularly attend screening. However, women from more deprived areas are much less likely to attend: for example in the 3 years from 2010-2012 only 63% of women in the most deprived area attended the East of Scotland Breast Screening programme versus 81% in the least deprived. Research has suggested that reminders (telephone or letter) and brief, personalised interventions addressing barriers to attendance may be helpful in increasing uptake in low-income women. METHODS/DESIGN We will employ a brief telephone reminder and support intervention, whose purpose is to elicit and address any mistaken beliefs women have about breast screening, with the aim that the perceived benefits of screening come to outweigh any perceived barriers for individuals. We will test whether this intervention, plus a simple anticipated regret manipulation, will lead to an increase in the uptake of breast cancer screening amongst low-income women who have failed to attend a first appointment, in a randomised controlled trial with 600 women. Participants will be randomly allocated to one of four treatment arms i.e. 1) Letter reminder (i.e. Treatment as usual: CONTROL); 2) Telephone reminder (TEL), 3) Telephone reminder plus telephone support (TEL-SUPP) and 4) Telephone reminder plus support plus AR (TEL-SUPP-AR). The primary outcome will be attendance at breast screening within 3 months of the reminder letter. DISCUSSION If this simple telephone support intervention (with or without AR intervention) leads to a significant increase in breast screening attendance, this would represent a rare example of a theoretically-driven, relatively simple psychological intervention that could result in earlier detection of breast cancer amongst an under-served group of lower socio-economic women. TRIAL REGISTRATION Current Controlled trials: ISRCTN06039270. Registered 16th January 2014
Evolution in the Disks and Bulges of Group Galaxies since z=0.4
We present quantitative morphology measurements of a sample of optically
selected group galaxies at 0.3 < z < 0.55 using the Hubble Space Telescope
(HST) Advanced Camera for Surveys (ACS) and the GIM2D surface
brightness--fitting software package. The group sample is derived from the
Canadian Network for Observational Cosmology Field Redshift survey (CNOC2) and
follow-up Magellan spectroscopy. We compare these measurements to a similarly
selected group sample from the Millennium Galaxy Catalogue (MGC) at 0.05 < z <
0.12. We find that, at both epochs, the group and field fractional bulge
luminosity (B/T) distributions differ significantly, with the dominant
difference being a deficit of disk--dominated (B/T < 0.2) galaxies in the group
samples. At fixed luminosity, z=0.4 groups have ~ 5.5 +/- 2 % fewer
disk--dominated galaxies than the field, while by z=0.1 this difference has
increased to ~ 19 +/- 6 %. Despite the morphological evolution we see no
evidence that the group environment is actively perturbing or otherwise
affecting the entire existing disk population. At both redshifts, the disks of
group galaxies have similar scaling relations and show similar median
asymmetries as the disks of field galaxies. We do find evidence that the
fraction of highly asymmetric, bulge--dominated galaxies is 6 +/- 3 % higher in
groups than in the field, suggesting there may be enhanced merging in group
environments. We replicate our group samples at z=0.4 and z=0 using the
semi-analytic galaxy catalogues of Bower et al (2006). This model accurately
reproduces the B/T distributions of the group and field at z=0.1. However, the
model does not reproduce our finding that the deficit of disks in groups has
increased significantly since z=0.4.Comment: Accepted for publication in MNRAS. 20 pages, 17 figure
Hubble Space Telescope Imaging of the CFRS and LDSS Redshift Surveys---III. Field elliptical galaxies at 0.2 < z < 1.0
Surface photometry has been performed on a sample of 46 field elliptical
galaxies. These galaxies are described well by a deVaucouleurs R^{1/4} profile.
The sample was selected from the combined Canada-France and LDSS redshift
surveys and spans the range 0.20 < z < 1.00. The relationship between galaxy
half-light radius and luminosity evolves such that a galaxy of a given size is
more luminous by Delta M_B=-0.97 \pm 0.14 mag at z=0.92 and the mean rest-frame
color shifts blueward by Delta (U-V) =-0.68 \pm 0.11 at z=0.92 relative to the
local cluster relations. Approximately 1/3 of these elliptical galaxies exhibit
[OII] 3727 emission lines with equivalent widths > 15 angstroms indicating
ongoing star formation. Estimated star-formation rates imply that \le 5% of the
stellar mass in the elliptical galaxy population has been formed since z=1. We
see no evidence for a decline in the space density of early-type galaxies with
look-back time. The statistics and a comparison with local
luminosity functions are both consistent with the view that the population of
massive early-type galaxies was largely in place by z~1. This implies that
merging is not required since that time to produce the present-day space
density of elliptical galaxies.Comment: 21 pages plus 8 figures plus 5 tables. Accepted by Astrophysical
Journa
Network model of immune responses reveals key effectors to single and co-infection dynamics by a respiratory bacterium and a gastrointestinal helminth
Co-infections alter the host immune response but how the systemic and local processes at the site of infection interact is still unclear. The majority of studies on co-infections concentrate on one of the infecting species, an immune function or group of cells and often focus on the initial phase of the infection. Here, we used a combination of experiments and mathematical modelling to investigate the network of immune responses against single and co-infections with the respiratory bacterium Bordetella bronchiseptica and the gastrointestinal helminth Trichostrongylus retortaeformis. Our goal was to identify representative mediators and functions that could capture the essence of the host immune response as a whole, and to assess how their relative contribution dynamically changed over time and between single and co-infected individuals. Network-based discrete dynamic models of single infections were built using current knowledge of bacterial and helminth immunology; the two single infection models were combined into a co-infection model that was then verified by our empirical findings. Simulations showed that a T helper cell mediated antibody and neutrophil response led to phagocytosis and clearance of B. bronchiseptica from the lungs. This was consistent in single and co-infection with no significant delay induced by the helminth. In contrast, T. retortaeformis intensity decreased faster when co-infected with the bacterium. Simulations suggested that the robust recruitment of neutrophils in the co-infection, added to the activation of IgG and eosinophil driven reduction of larvae, which also played an important role in single infection, contributed to this fast clearance. Perturbation analysis of the models, through the knockout of individual nodes (immune cells), identified the cells critical to parasite persistence and clearance both in single and co-infections. Our integrated approach captured the within-host immuno-dynamics of bacteria-helminth infection and identified key components that can be crucial for explaining individual variability between single and co-infections in natural populations
Complex-Distance Potential Theory and Hyperbolic Equations
An extension of potential theory in R^n is obtained by continuing the
Euclidean distance function holomorphically to C^n. The resulting Newtonian
potential is generated by an extended source distribution D(z) in C^n whose
restriction to R^n is the delta function. This provides a natural model for
extended particles in physics. In C^n, interpreted as complex spacetime, D(z)
acts as a propagator generating solutions of the wave equation from their
initial values. This gives a new connection between elliptic and hyperbolic
equations that does not assume analyticity of the Cauchy data. Generalized to
Clifford analysis, it induces a similar connection between solutions of
elliptic and hyperbolic Dirac equations. There is a natural application to the
time-dependent, inhomogeneous Dirac and Maxwell equations, and the
`electromagnetic wavelets' introduced previously are an example.Comment: 25 pages, submited to Proceedings of 5th Intern. Conf. on Clifford
Algebras, Ixtapa, June 24 - July 4, 199
The morphologies and masses of extremely red galaxies in the Groth Strip survey
We present a new cataloge of EROs from the Groth strip and study the relation
between their morphology and mass. We find 102 EROs (F814W-K=>4, K<=21.0), over
a survey area of 155 arcmin^2. The photometric data include U,B,F606W,F814W,J,K
bands. Morphologies are based on a by eye classification and we distinguish
between 3 basic classes: compact objects, targets with a disc and/or a bulge
component and irregular or merger candidates. The majority of our targets has
either a very compact morphology (33+-6%), or show more or less distinct disc
components (41+-6%). 14+-4% are merger or irregulars and 7 objects could not be
classified. We also study the dependence of structural parameters on
morphological appearance. EROs that are either compact or show a distinct bulge
component have smaller median effective radii (1.22+-0.14 kpc and 3.31+-0.53
kpc) than disc dominated (5.50+-0.51 kpc) or possible irregular galaxies or
merger candidates (4.92+-0.14 kpc). The Sersic index changes from 2.30+-0.34
and 3.24+-0.55, to 1.03+-0.24 and 1.54+-0.40 respectively.
Most the EROs in our sample have redshifts between z=1 and z=2; however,
compact EROs in our sample are found at redshifts as low as z=0.4 and as high
as z=2.8; the latter qualify as well as DRGs. Disc-like EROs are also found up
to z=2.8; however those with a bulge-disc structure are only seen at z<1.5. For
each of these EROs we determined the stellar mass and mean population age by
fitting synthetic Bruzual (2007) spectra to the SED. Mass estimates were
obtained by assuming an exponentially declining star formation rate. Total
stellar masses are in the range 9.1<log(M/M_sun)<11.6. We cannot detect
significant differences between the stellar mass distribution of the
morphological classes. EROs with masses of log(M/M_sun)>11.0 dominantly show
compact morphologies, but also include a significant number of sources with a
disc morphology.Comment: 21 pages, 17 figures, accepted for publication in MNRA
Automated Morphological Classification of SDSS Red Sequence Galaxies
(abridged) In the last decade, the advent of enormous galaxy surveys has
motivated the development of automated morphological classification schemes to
deal with large data volumes. Existing automated schemes can successfully
distinguish between early and late type galaxies and identify merger
candidates, but are inadequate for studying detailed morphologies of red
sequence galaxies. To fill this need, we present a new automated classification
scheme that focuses on making finer distinctions between early types roughly
corresponding to Hubble types E, S0, and Sa. We visually classify a sample of
984 non-starforming SDSS galaxies with apparent sizes >14". We then develop an
automated method to closely reproduce the visual classifications, which both
provides a check on the visual results and makes it possible to extend
morphological analysis to much larger samples. We visually classify the
galaxies into three bulge classes (BC) by the shape of the light profile in the
outer regions: discs have sharp edges and bulges do not, while some galaxies
are intermediate. We separately identify galaxies with features: spiral arms,
bars, clumps, rings, and dust. We find general agreement between BC and the
bulge fraction B/T measured by the galaxy modeling package GIM2D, but many
visual discs have B/T>0.5. Three additional automated parameters -- smoothness,
axis ratio, and concentration -- can identify many of these high-B/T discs to
yield automated classifications that agree ~70% with the visual classifications
(>90% within one BC). Both methods are used to study the bulge vs. disc
frequency as a function of four measures of galaxy 'size': luminosity, stellar
mass, velocity dispersion, and radius. All size indicators show a fall in disc
fraction and a rise in bulge fraction among larger galaxies.Comment: 24 pages, 20 figures, MNRAS accepte
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