3,371 research outputs found
SkyDOT (Sky Database for Objects in the Time Domain): A Virtual Observatory for Variability Studies at LANL
The mining of Virtual Observatories (VOs) is becoming a powerful new method
for discovery in astronomy. Here we report on the development of SkyDOT (Sky
Database for Objects in the Time domain), a new Virtual Observatory, which is
dedicated to the study of sky variability. The site will confederate a number
of massive variability surveys and enable exploration of the time domain in
astronomy. We discuss the architecture of the database and the functionality of
the user interface. An important aspect of SkyDOT is that it is continuously
updated in near real time so that users can access new observations in a timely
manner. The site will also utilize high level machine learning tools that will
allow sophisticated mining of the archive. Another key feature is the real time
data stream provided by RAPTOR (RAPid Telescopes for Optical Response), a new
sky monitoring experiment under construction at Los Alamos National Laboratory
(LANL).Comment: to appear in SPIE proceedings vol. 4846, 11 pages, 5 figure
Instantaneous Normal Mode Analysis of Supercooled Water
We use the instantaneous normal mode approach to provide a description of the
local curvature of the potential energy surface of a model for water. We focus
on the region of the phase diagram in which the dynamics may be described by
the mode-coupling theory. We find, surprisingly, that the diffusion constant
depends mainly on the fraction of directions in configuration space connecting
different local minima, supporting the conjecture that the dynamics are
controlled by the geometric properties of configuration space. Furthermore, we
find an unexpected relation between the number of basins accessed in
equilibrium and the connectivity between them.Comment: 5 pages, 4 figure
Integrating the Fermi Gamma-Ray Burst Monitor into the 3rd Interplanetary Network
We are integrating the Fermi Gamma-Ray Burst Monitor (GBM) into the
Interplanetary Network (IPN) of Gamma-Ray Burst (GRB) detectors. With the GBM,
the IPN will comprise 9 experiments. This will 1) assist the Fermi team in
understanding and reducing their systematic localization uncertainties, 2)
reduce the sizes of the GBM and Large Area Telescope (LAT) error circles by 1
to 4 orders of magnitude, 3) facilitate the identification of GRB sources with
objects found by ground- and space-based observatories at other wavelengths,
from the radio to very high energy gamma-rays, 4) reduce the uncertainties in
associating some LAT detections of high energy photons with GBM bursts, and 5)
facilitate searches for non-electromagnetic GRB counterparts, particularly
neutrinos and gravitational radiation. We present examples and demonstrate the
synergy between Fermi and the IPN. This is a Fermi Cycle 2 Guest Investigator
project.Comment: 5 pages, 11 figures. 2009 Fermi Symposium. eConf Proceedings C09112
Interplanetary Network Localization of GRB991208 and the Discovery of its Afterglow
The extremely energetic (~10^-4 erg/cm^2) gamma-ray burst (GRB) of 1999
December 8 was triangulated to a ~14 sq. arcmin. error box ~1.8 d after its
arrival at Earth with the 3rd interplanetary network (IPN), consisting of the
Ulysses, Near Earth Asteroid Rendezvous (NEAR), and WIND spacecraft. Radio
observations with the Very Large Array ~2.7 d after the burst revealed a bright
fading counterpart whose position is consistent with that of an optical
transient source whose redshift is z=0.707. We present the time history, peak
flux, fluence, and refined 1.3 sq. arcmin. error box of this event, and discuss
its energetics. This is the first time that a counterpart has been found for a
GRB localized only by the IPN.Comment: Revised version, accepted for publication in the Astrophysical
Journal Letter
Thermodynamic and structural aspects of the potential energy surface of simulated water
Relations between the thermodynamics and dynamics of supercooled liquids
approaching a glass transition have been proposed over many years. The
potential energy surface of model liquids has been increasingly studied since
it provides a connection between the configurational component of the partition
function on one hand, and the system dynamics on the other. This connection is
most obvious at low temperatures, where the motion of the system can be
partitioned into vibrations within a basin of attraction and infrequent
inter-basin transitions. In this work, we present a description of the
potential energy surface properties of supercooled liquid water. The dynamics
of this model has been studied in great details in the last years.
Specifically, we locate the minima sampled by the liquid by ``quenches'' from
equilibrium configurations generated via molecular dynamics simulations. We
calculate the temperature and density dependence of the basin energy,
degeneracy, and shape. The temperature dependence of the energy of the minima
is qualitatively similar to simple liquids, but has anomalous density
dependence. The unusual density dependence is also reflected in the
configurational entropy, the thermodynamic measure of degeneracy. Finally, we
study the structure of simulated water at the minima, which provides insight on
the progressive tetrahedral ordering of the liquid on cooling
The SARS-CoV-2 Delta variant induces an antibody response largely focused on class 1 and 2 antibody epitopes
Common polygenic risk for autism spectrum disorder (ASD) is associated with cognitive ability in the general population
Acknowledgements Generation Scotland has received core funding from the Chief Scientist Office of the Scottish Government Health Directorates CZD/16/6 and the Scottish Funding Council HR03006. We are grateful to all the families who took part, the general practitioners and the Scottish School of Primary Care for their help in recruiting them and the whole Generation Scotland team, which includes interviewers, computer and laboratory technicians, clerical workers, research scientists, volunteers, managers, receptionists, health-care assistants and nurses. We acknowledge with gratitude the financial support received for this work from the Dr Mortimer and Theresa Sackler Foundation. For the Lothian Birth Cohorts (LBC1921 and LBC1936), we thank Paul Redmond for database management assistance; Alan Gow, Martha Whiteman, Alison Pattie, Michelle Taylor, Janie Corley, Caroline Brett and Caroline Cameron for data collection and data entry; nurses and staff at the Wellcome Trust Clinical Research Facility, where blood extraction and genotyping was performed; staff at the Lothian Health Board; and the staff at the SCRE Centre, University of Glasgow. The research was supported by a program grant from Age UK (Disconnected Mind) and by grants from the Biotechnology and Biological Sciences Research Council (BBSRC). The work was undertaken by The University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology, part of the cross council Lifelong Health and Wellbeing Initiative (MR/K026992/1). Funding from the Medical Research Council (MRC) and BBSRC is gratefully acknowledged. DJM is an NRS Career Research Fellow funded by the CSO. BATS were funded by the Australian Research Council (A79600334, A79906588, A79801419, DP0212016, DP0664638, and DP1093900) and the National Health and Medical Research Council (389875) Australia. MKL is supported by a Perpetual Foundation Wilson Fellowship. SEM is supported by a Future Fellowship (FT110100548) from the Australian Research Council. GWM is supported by a National Health and Medical Research Council (NHMRC), Australia, Fellowship (619667). We thank the twins and siblings for their participation, Marlene Grace, Ann Eldridge and Natalie Garden for cognitive assessments, Kerrie McAloney, Daniel Park, David Smyth and Harry Beeby for research support, Anjali Henders and staff in the Molecular Epidemiology Laboratory for DNA sample processing and preparation and Scott Gordon for quality control and management of the genotypes. This work is supported by a Stragetic Award from the Wellcome Trust, reference 104036/Z/14/Z.Peer reviewedPublisher PD
The RAPTOR Experiment: A System for Monitoring the Optical Sky in Real Time
The Rapid Telescopes for Optical Response (RAPTOR) experiment is a spatially
distributed system of autonomous robotic telescopes that is designed to monitor
the sky for optical transients. The core of the system is composed of two
telescope arrays, separated by 38 kilometers, that stereoscopically view the
same 1500 square-degree field with a wide-field imaging array and a central 4
square-degree field with a more sensitive narrow-field "fovea" imager. Coupled
to each telescope array is a real-time data analysis pipeline that is designed
to identify interesting transients on timescales of seconds and, when a
celestial transient is identified, to command the rapidly slewing robotic
mounts to point the narrow-field ``fovea'' imagers at the transient. The two
narrow-field telescopes then image the transient with higher spatial resolution
and at a faster cadence to gather light curve information. Each "fovea" camera
also images the transient through a different filter to provide color
information. This stereoscopic monitoring array is supplemented by a rapidly
slewing telescope with a low resolution spectrograph for follow-up observations
of transients and a sky patrol telescope that nightly monitors about 10,000
square-degrees for variations, with timescales of a day or longer, to a depth
about 100 times fainter. In addition to searching for fast transients, we will
use the data stream from RAPTOR as a real-time sentinel for recognizing
important variations in known sources. Altogether, the RAPTOR project aims to
construct a new type of system for discovery in optical astronomy--one that
explores the time domain by "mining the sky in real time".Comment: 11 pages, To appear in the Proceedings of the SPIE, Volume 484
- …