227 research outputs found
Interactive Visualization: Video Walls for Collaborative Research and Discovery (Snapshot of CURVE)
Discusses large-scale video walls in libraries designed for collaboration that can change users’ perspective and reframe and amplify digital content in shared physical spaces. Georgia State University Library’s newly-opened CURVE: Collaborative University Research & Visualization Environment features a 24-by-4.5-foot, high-resolution CURVE interactWall that expands student and faculty access to digital resources, data visualization, and more
Spatial, Temporal and Spectral Properties of X-ray Emission from the Magnetar SGR~0501+4516
SGR~0501+4516 was discovered with the Swift satellite on 2008 August 22,
after it emitted a series of very energetic bursts. Since then, the source was
extensively monitored with Swift, the Rossi X-ray Timing Explorer (RXTE) and
observed with Chandra and XMM-Newton, providing a wealth of information about
its outburst behavior and burst induced changes of its persistent X-ray
emission. Here we report the most accurate location of SGR~0501+4516 (with an
accuracy of 0.11'') derived with Chandra. Using the combined RXTE, Swift/X-ray
Telescope, Chandra and XMM-Newton observations we construct a phase connected
timing solution with the longest time baseline (~240 days) to date for the
source. We find that the pulse profile of the source is energy dependent and
exhibits remarkable variations associated with the SGR~0501+4516 bursting
activity. We also find significant spectral evolution (hardening) of the source
persistent emission associated with bursts. Finally, we discuss the
consequences of the SGR~0501+4516 proximity to the supernova remnant, SNR
G160.9+2.6 (HB9).Comment: Accepted for publication in the Ap
Test-retest reliability of capability measurement in the UK general population
Although philosophically attractive, it may be difficult, in practice, to measure individuals' capabilities (what they are able to do in their lives) as opposed to their functionings (what they actually do). To examine whether capability information could be reliably self-reported, we administered a measure of self-reported capability (the Investigating Choice Experiments Capability Measure for Adults, ICECAP-A) on two occasions, 2 weeks apart, alongside a self-reported health measure (the EuroQol Five Dimensional Questionnaire with 3 levels, EQ-5D-3L). We found that respondents were able to report capabilities with a moderate level of consistency, although somewhat less reliably than their health status. The more socially orientated nature of some of the capability questions may account for the difference. © 2014 The Authors Health Economics Published by John Wiley & Sons Ltd
Validating First-Principles Phonon Lifetimes via Inelastic Neutron Scattering
Phonon lifetimes are a key component of quasiparticle theories of transport,
yet first-principles lifetimes are rarely directly compared to inelastic
neutron scattering (INS) results. Existing comparisons show discrepancies even
at temperatures where perturbation theory is expected to be reliable. In this
work, we demonstrate that the reciprocal space voxel (-voxel), which is the
finite region in reciprocal space required in INS data analysis, must be
explicitly accounted for within theory in order to draw a meaningful
comparison. We demonstrate accurate predictions of peak widths of the
scattering function when accounting for the -voxel in CaF and ThO.
Passing this test implies high fidelity of the phonon interactions and the
approximations used to compute the Green's function, serving as critical
benchmark of theory, and indicating that other material properties should be
accurately predicted; which we demonstrate for thermal conductivity
Anomalous X-ray pulsars and soft gamma-ray repeaters - the connection with supernova remnants
Many of the properties of anomalous X-ray pulsars (AXPs) and soft gamma-ray
repeaters (SGRs) are still a matter of much debate, as is the connection (if
any) between these two groups of sources. In cases where we can identify the
supernova remnant (SNR) associated with an AXP or SGR, the extra information
thus obtained can provide important constraints as to the nature of these
exotic objects. In this paper, I explain the criteria by which an association
between a SNR and an AXP/SGR should be judged, review the set of associations
which result, and discuss the implications provided by these associations for
the ages, environments and evolutionary pathways of the AXPs and SGRs. There
are several convincing associations between AXPs and SNRs, demonstrating that
AXPs are young neutron stars with moderate space velocities. The lack of
associations between SGRs and SNRs implies that the SGRs either represent an
older population of neutron stars than do the AXPs, or originate from more
massive progenitors.Comment: 10 pages, 3 embedded EPS figures, 3 JPG figures, uses cospar.sty.
Invited review to appear in "High Energy Studies of Supernova Remnants and
Neutron Stars" (COSPAR 2002), Advances in Space Research, in press. PS
version with all figures embedded available at
http://cfa-www.harvard.edu/~bgaensler/preprints/0212086.p
Continuous and Long-Term Volume Measurements with a Commercial Coulter Counter
We demonstrate a method to enhance the time resolution of a commercial Coulter counter and enable continuous and long-term cell size measurements for growth rate analyses essential to understanding basic cellular processes, such as cell size regulation and cell cycle progression. Our simple modifications to a commercial Coulter counter create controllable cell culture conditions within the sample compartment and combine temperature control with necessary adaptations to achieve measurement stability over several hours. We also wrote custom software, detailed here, to analyze instrument data files collected by either this continuous method or standard, periodic sampling. We use the continuous method to measure the growth rate of yeast in G1 during a prolonged arrest and, in different samples, the dependency of growth rate on cell size and cell cycle position in arrested and proliferating cells. We also quantify with high time resolution the response of mouse lymphoblast cell culture to drug treatment. This method provides a technique for continuous measurement of cell size that is applicable to a large variety of cell types and greatly expands the set of analysis tools available for the Coulter counter.National Institutes of Health (U.S.) (EUREKA Exceptional, Unconventional Research Enabling Knowledge Acceleration (R01GM085457))National Institutes of Health (U.S.) (contract R21CA137695)National Cancer Institute (U.S.). Physical Sciences-Oncology Center (U54CA143874
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The effect of horizontal resolution on Indian monsoon depressions in the Met Office NWP model
Monsoon depressions are synoptic scale features that are responsible for a significant fraction of the rain over northern India during the summer monsoon season, and, as such, it is important to quantify their structure and behaviour in numerical weather prediction models. It is known that increasing model resolution is strongly correlated with improved forecasts in the short term and global circulation in the longer term, as well as better representation of tropical cyclones; here, we explore the sensitivity of depressions to changes in resolution using the Met Office Unified Model. Seven NWP case studies of depressions from 2013-15 were run at eight resolutions corresponding to equatorial grid spacing of between 16 and 208 km, and compared with data for the same events from TRMM and ERA-Interim reanalysis. We found that at the low resolution end of the spectrum, increases in resolution led to improvements in the composite structure, but with diminishing returns. The model also persistently overestimated the depression intensity, in particular the wind speed and the warm core aloft -- with the source appearing to originate in the mid-troposphere. The sensitivity of the diurnal cycle to resolution was also explored: the stratiform component was found to be very well represented by the model, whereas the convective component was described quite poorly. Improvement in most components of structure with increasing model resolution were marginal beyond N320 (63 km) and N512 (39 km) for dynamic and thermodynamic fields respectively
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