227 research outputs found
The LCOGT Network
Motivated by the increasing need for observational resources for the study of
time varying astronomy, the Las Cumbres Observatory Global Telescope (LCOGT) is
a private foundation, whose goal is to build a global network of robotic
telescopes for scientific research and education. Once completed, the network
will become a unique tool, capable of continuous monitoring from both the
Northern and Southern Hemispheres. The network currently includes 2 x 2.0 m
telescopes, already making an impact in the field of exoplanet research. In the
next few years they will be joined by at least 12 x 1.0 m and 20 x 0.4 m
telescopes. The increasing amount of LCOGT observational resources in the
coming years will be of great service to the astronomical community in general,
and the exoplanet community in particular.Comment: 2 pages, 1 figure, to appear in the proceedings of IAU Symposium 276
"The Astrophysics of Planetary Systems: Formation, Structure, and Dynamical
Evolution
Managing Contemporary UK Universities – Manager-academics and New Managerialism
A multi-disciplinary project entitled ‘New Managerialism and the Management of UK Universities’ was conducted by a team of researchers based at Lancaster University between October 1998 and November 2000. The study was funded by the UK Economic and Social Research Council (grant no R000237661). The project was designed to examine the extent to which ‘New Managerialism’, a set of reforms of the management of publicly-funded services popular with many western governments, was perceived to have permeated the management of UK universities. The study also explored the roles, practices, selection, learning and support of manager-academics. The first phase of the study comprised focus group discussions with learned societies from several disciplines where respondents considered what was currently happening to the management of universities. The second phase involved interviews with 135 manager-academics (from Head of Department to Vice Chancellor) and 29 senior administrators in 12 pre-1992 and post-1992 universities. The interviews explored the backgrounds, current management practices and perceptions of respondents. In phase 3, case studies of the cultures and management of four universities enabled comparison of the views of manager-academics with those of academics and support staff
Haldane limits via Lagrangian embeddings
In the present paper we revisit the so-called Haldane limit, i.e. a
particular continuum limit, which leads from a spin chain to a sigma model. We
use the coherent state formulation of the path integral to reduce the problem
to a semiclassical one, which leads us to the observation that the Haldane
limit is closely related to a Lagrangian embedding into the classical phase
space of the spin chain. Using this property, we find a spin chain whose limit
produces a relativistic sigma model with target space the manifold of complete
flags U(N)/U(1)^N. We discuss possible other future applications of
Lagrangian/isotropic embeddings in this context.Comment: 29 pages, 2 figure
Wide-Orbit Exoplanet Demographics
The Kepler, K2 and TESS transit surveys are revolutionizing our understanding of planets orbiting close to their host stars and our understanding of exoplanet systems in general, but there remains a gap in our understanding of wide-orbit planets. This gap in our understanding must be filled if we are to understand planet formation and how it affects exoplanet habitability. We summarize current and planned exoplanet detection programs using a variety of methods: microlensing (including WFIRST), radial velocities, Gaia astrometry, and direct imaging. Finally, we discuss the prospects for joint analyses using results from multiple methods and obstacles that could hinder such analyses.
We endorse the findings and recommendations published in the 2018 National Academy report on Exoplanet Science Strategy. This white paper extends and complements the material presented therein
PFD: a database for the investigation of protein folding kinetics and stability
We have developed a new database that collects all protein folding data into a single, easily accessible public resource. The Protein Folding Database (PFD) contains annotated structural, methodological, kinetic and thermodynamic data for more than 50 proteins, from 39 families. A user-friendly web interface has been developed that allows powerful searching, browsing and information retrieval, whilst providing links to other protein databases. The database structure allows visualization of folding data in a useful and novel way, with a long-term aim of facilitating data mining and bioinformatics approaches. PFD can be accessed freely at http://pfd.med.monash.edu.au
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A novel retinoblastoma therapy from genomic and epigenetic analyses.
Retinoblastoma is an aggressive childhood cancer of the developing retina that is initiated by the biallelic loss of RB1. Tumours progress very quickly following RB1 inactivation but the underlying mechanism is not known. Here we show that the retinoblastoma genome is stable, but that multiple cancer pathways can be epigenetically deregulated. To identify the mutations that cooperate with RB1 loss, we performed whole-genome sequencing of retinoblastomas. The overall mutational rate was very low; RB1 was the only known cancer gene mutated. We then evaluated the role of RB1 in genome stability and considered non-genetic mechanisms of cancer pathway deregulation. For example, the proto-oncogene SYK is upregulated in retinoblastoma and is required for tumour cell survival. Targeting SYK with a small-molecule inhibitor induced retinoblastoma tumour cell death in vitro and in vivo. Thus, retinoblastomas may develop quickly as a result of the epigenetic deregulation of key cancer pathways as a direct or indirect result of RB1 loss
KELT-7b: A hot Jupiter transiting a bright V=8.54 rapidly rotating F-star
We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of
MJ, radius of RJ, and an orbital
period of days. The bright host star (HD33643;
KELT-7) is an F-star with , Teff K, [Fe/H]
, and . It has a mass of
Msun, a radius of Rsun, and
is the fifth most massive, fifth hottest, and the ninth brightest star known to
host a transiting planet. It is also the brightest star around which KELT has
discovered a transiting planet. Thus, KELT-7b is an ideal target for detailed
characterization given its relatively low surface gravity, high equilibrium
temperature, and bright host star. The rapid rotation of the star (
km/s) results in a Rossiter-McLaughlin effect with an unusually large amplitude
of several hundred m/s. We find that the orbit normal of the planet is likely
to be well-aligned with the stellar spin axis, with a projected spin-orbit
alignment of degrees. This is currently the second most
rapidly rotating star to have a reflex signal (and thus mass determination) due
to a planetary companion measured.Comment: Accepted to The Astronomical Journa
Wide-Orbit Exoplanet Demographics
The Kepler, K2 and TESS transit surveys are revolutionizing our understanding of planets orbiting close to their host stars and our understanding of exoplanet systems in general, but there remains a gap in our understanding of wide-orbit planets. This gap in our understanding must be filled if we are to understand planet formation and how it affects exoplanet habitability. We summarize current and planned exoplanet detection programs using a variety of methods: microlensing (including WFIRST), radial velocities, Gaia astrometry, and direct imaging. Finally, we discuss the prospects for joint analyses using results from multiple methods and obstacles that could hinder such analyses.
We endorse the findings and recommendations published in the 2018 National Academy report on Exoplanet Science Strategy. This white paper extends and complements the material presented therein
KELT-1b: A Strongly Irradiated, Highly Inflated, Short Period, 27 Jupiter-mass Companion Transiting a mid-F Star
We present the discovery of KELT-1b, the first transiting low-mass companion
from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North)
survey. The V=10.7 primary is a mildly evolved, solar-metallicity, mid-F star.
The companion is a low-mass brown dwarf or super-massive planet with mass of
27.23+/-0.50 MJ and radius of 1.110+0.037-0.024 RJ, on a very short period
(P=1.21750007) circular orbit. KELT-1b receives a large amount of stellar
insolation, with an equilibrium temperature assuming zero albedo and perfect
redistribution of 2422 K. Upper limits on the secondary eclipse depth indicate
that either the companion must have a non-zero albedo, or it must experience
some energy redistribution. Comparison with standard evolutionary models for
brown dwarfs suggests that the radius of KELT-1b is significantly inflated.
Adaptive optics imaging reveals a candidate stellar companion to KELT-1, which
is consistent with an M dwarf if bound. The projected spin-orbit alignment
angle is consistent with zero stellar obliquity, and the vsini of the primary
is consistent with tidal synchronization. Given the extreme parameters of the
KELT-1 system, we expect it to provide an important testbed for theories of the
emplacement and evolution of short-period companions, and theories of tidal
dissipation and irradiated brown dwarf atmospheres.Comment: 30 pages, 19 figures. Submitted to Ap
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