319 research outputs found
Recommended from our members
MTR-Viewer: Identifying regions within genes under purifying selection
Advances in genomic sequencing have enormous potential to revolutionise personalised medicine, however distinguishing disease-causing from benign variants remains a challenge. The increasing number of human genome and exome sequences available has revealed areas where unfavourable variation is removed through purifying selection. Here we present the MTR-Viewer, a web-server enabling easy visualisation at the gene or variant level of the Missense Tolerance Ratio (MTR), a measure of regional intolerance to missense variation calculated using variation from 220,000 exome and genome sequences. The MTR-Viewer enables exploration of MTR calculations, using different sliding windows, for over 18,000 human protein-coding genes and 85,000 alternative transcripts. Users can also view MTR scores calculated for specific ethnicities, to enable easy exploration of regions that may be under different selective pressure. The spatial distribution of population and known disease variants is also displayed on the proteinâs domain structure. Intolerant regions were found to be highly enriched for ClinVar pathogenic and COSMIC somatic missense variants (Mann-Whitney U test p < 2.2x10-16). As the MTR is not biased by known domains and protein features, it can highlight functionally important regions within genes overlooked or inaccessible by traditional methods. MTR-Viewer is freely available via a user friendly web-server at http://biosig.unimelb.edu.au/mtr-viewer/.M.S. was supported by the Australian Government Research Training Program. S.P. was supported by an NHMRC R.D. Wright Career Development Fellowship (1126877). S.P. is an employee of AstraZeneca. D.B.A. was supported by the Jack Brockhoff Foundation [JBF 4186, 2016], a Newton Fund RCUK-CONFAP Grant awarded by The Medical Research Council (MRC) [MR/M026302/1]; the National Health and Medical Research Council of Australia [APP1072476]; and the Department of Biochemistry and Molecular Biology, University of Melbourne
A Theoretical Model for the Relation for Supermassive Black Holes in Galaxies
We construct a model for the formation of black holes within galactic bulges.
The initial state is a slowly rotating isothermal sphere, characterized by
effective transport speed \aeff and rotation rate . The black hole
mass is determined when the centrifugal radius of the collapse flow exceeds the
capture radius of the central black hole. This model reproduces the observed
correlation between black hole masses and galactic velocity dispersions, \mbh
\approx 10^8 M_\odot (\sigma/200 \kms)^4, where \sigma = \sqrt{2} \aeff.
This model also predicts the ratio \mrat of black hole mass to host mass:
\mrat 0.004 (\sigma/200 \kms).Comment: 9 pages, 2 figures, submitted to Astrophysical Journal Letter
Supermassive Black Holes in Active Galactic Nuclei. I. The Consistency of Black Hole Masses in Quiescent and Active Galaxies
We report the first results of a program to measure accurate stellar velocity
dispersions in the bulges of the host galaxies of active galactic nuclei (AGNs)
for which accurate black hole (BH) masses have been determined via
reverberation mapping. We find good agreement between BH masses obtained from
reverberation mapping, and from the M(BH) - sigma relation as defined by
quiescent galaxies, indicating a common relationship between active and
quiescent black holes and their large-scale environments.Comment: Submitted to ApJ
Dominant Nuclear Outflow Driving Mechanisms in Powerful Radio Galaxies
In order to identify the dominant nuclear outflow mechanisms in Active
Galactic Nuclei, we have undertaken deep, high resolution observations of two
compact radio sources (PKS 1549-79 and PKS 1345+12) with the Advanced Camera
for Surveys (ACS) aboard the Hubble Space Telescope. Not only are these targets
known to have powerful emission line outflows, but they also contain all the
potential drivers for the outflows: relativistic jets, quasar nuclei and
starbursts. ACS allows the compact nature (<0.15") of these radio sources to be
optically resolved for the first time. Through comparison with existing radio
maps we have seen consistency in the nuclear position angles of both the
optical emission line and radio data. There is no evidence for bi-conical
emission line features on the large-scale and there is a divergance in the
relative position angles of the optical and radio structure. This enables us to
exclude starburst driven outflows. However, we are unable to clearly
distinguish between radiative AGN wind driven outflows and outflows powered by
relativistic radio jets. The small scale bi-conical features, indicative of
such mechanisms could be below the resolution limit of ACS, especially if
aligned close to the line of sight. In addition, there may be offsets between
the radio and optical nuclei induced by heavy dust obscuration, nebular
continuum or scattered light from the AGN.Comment: 9 pages, 8 figures, emulateapj, ApJ Accepte
Cosmic Microwave Background Dipole induced by double inflation
The observed CMBR dipole is generally interpreted as the consequence of the
peculiar motion of the Sun with respect to the reference frame of the CMBR.
This article proposes an alternative interpretation in which the observed
dipole is the result of isocurvature perturbations on scales larger than the
present Hubble radius. These perturbations are produced in the simplest model
of double inflation, depending on three parameters. The observed dipole and
quadrupole can be explained in this model, while severely constraining its
parameters.Comment: Latex, 9 pages, no figure, to appear in Phys. Rev.
Correlated adiabatic and isocurvature perturbations from double inflation
It is shown that double inflation (two minimally coupled massive scalar
fields) can produce correlated adiabatic and isocurvature primordial
perturbations. Depending on the two relevant parameters of the model, the
contributions to the primordial perturbations are computed, with special
emphasis on the correlation, which can be quantitatively represented by a
correlation spectrum. Finally the primordial spectra are evolved numerically to
obtain the CMBR anisotropy multipole expectation values. It turns out that the
existence of mixing and correlation can alter very significantly the
temperature fluctuation predictions.Comment: 23 pages, 7 figures, RevTex. To appear in Phys. Rev.
Inelastic Dark Matter
Many observations suggest that much of the matter of the universe is
non-baryonic. Recently, the DAMA NaI dark matter direct detection experiment
reported an annual modulation in their event rate consistent with a WIMP relic.
However, the Cryogenic Dark Matter Search (CDMS) Ge experiment excludes most of
the region preferred by DAMA. We demonstrate that if the dark matter can only
scatter by making a transition to a slightly heavier state (Delta m ~ 100kev),
the experiments are no longer in conflict. Moreover, differences in the energy
spectrum of nuclear recoil events could distinguish such a scenario from the
standard WIMP scenario. Finally, we discuss the sneutrino as a candidate for
inelastic dark matter in supersymmetric theories.Comment: 20 pages, 6 figure
- âŠ