71 research outputs found
A New Seismic-Geotechnical Strong Motion Approach
We have developed a new approach to estimate site-specific strong motion due to earthquakes on specific faults or source zones. It combines seismologic and geotechnical studies. It entails obtaining records of small earthquakes at the site, both at the surface and downhole in bedrock, as well as performing geotechnical dynamic site characterization. This new approach has the dual result of providing an optimized definition of the dynamic geotechnical site properties and providing calculated free-field, strong motion estimates. The procedure is demonstrated at the Painter Street Bridge site in Rio Dell, CA, for which we provide a range of surface motions corresponding to an earthquake of magnitude 7 on the subducting plate underlying this region. These calculated motions bracket the records of the Petrolia event (M = 7) measured near the site
A Hubble Space Telescope Survey of Extended [OIII]5007A Emission in a Far-Infrared Selected Sample of Seyfert Galaxies: Results
We present the results of a Hubble Space Telescope (HST) survey of extended
[OIII] emission in a sample of 60 nearby Seyfert galaxies (22 Seyfert 1's and
38 Seyfert 2's), selected by mostly isotropic properties. The comparison
between the semi major axis size of their [OIII] emitting regions (R_Maj) shows
that Seyfert 1's and Seyfert 2's have similar distributions, which seems to
contradict Unified Model predictions. We discuss possible ways to explain this
result, which could be due either to observational limitations or the models
used for the comparison with our data. We show that Seyfert 1 Narrow Line
Regions (NLR's) are more circular and concentrated than Seyfert 2's, which can
be attributed to foreshortening in the former. We find a good correlation
between the NLR size and luminosity, following the relation R_Maj propto
L([OIII])^0.33, which is flatter than a previous one found for QSO's and
Seyfert 2's. We discuss possible reasons for the different results, and their
implications to photoionization models. We confirm previous results which show
that the [OIII] and radio emission are well aligned, and also find no
correlation between the orientation of the extended [OIII] emission and the
host galaxy major axis. This agrees with results showing that the torus axis
and radio jet are not aligned with the host galaxy rotation axis, indicating
that the orientation of the gas in the torus, and not the spin of the black
hole, determine the orientation of the accretion disk, and consequently the
orientation of the radio jet.Comment: 17 pages including 12 figures, to appear in Ap
The ethical challenge of Touraine's 'living together'
In Can We Live Together? Alain Touraine combines a consummate analysis of crucial social tensions in contemporary societies with a strong normative appeal for a new emancipatory 'Subject' capable of overcoming the twin threats of atomisation or authoritarianism. He calls for a move from 'politics to ethics' and then from ethics back to politics to enable the new Subject to make a reality out of the goals of democracy and solidarity. However, he has little to say about the nature of such an ethics. This article argues that this lacuna could usefully be filled by adopting a form of radical humanism found in the work of Erich Fromm. It defies convention in the social sciences by operating from an explicit view of the 'is' and the 'ought' of common human nature, specifying reason, love and productive work as the qualities to be realised if we are to move closer to human solidarity. Although there remain significant philosophical and political differences between the two positions, particularly on the role to be played by 'the nation', their juxtaposition opens new lines of inquiry in the field of cosmopolitan ethics
Role of Imaging in the Staging and Response Assessment of Lymphoma:Consensus of the International Conference on Malignant Lymphomas Imaging Working Group
This article comprises the consensus reached to update guidance on the use of PET-CT for staging and response assessment for 18F FDG-avid lymphomas in clinical practice and late-phase trials
Eddington-limited accretion and the black hole mass function at redshift 6
We present discovery observations of a quasar in the Canada-France High-z
Quasar Survey (CFHQS) at redshift z=6.44. We also use near-IR spectroscopy of
nine CFHQS quasars at z~6 to determine black hole masses. These are compared
with similar estimates for more luminous Sloan Digital Sky Survey (SDSS)
quasars to investigate the relationship between black hole mass and quasar
luminosity. We find a strong correlation between MgII FWHM and UV luminosity
and that most quasars at this early epoch are accreting close to the Eddington
limit. Thus these quasars appear to be in an early stage of their life cycle
where they are building up their black hole mass exponentially. Combining these
results with the quasar luminosity function, we derive the black hole mass
function at z=6. Our black hole mass function is ~10^4 times lower than at z=0
and substantially below estimates from previous studies. The main uncertainties
which could increase the black hole mass function are a larger population of
obscured quasars at high-redshift than is observed at low-redshift and/or a low
quasar duty cycle at z=6. In comparison, the global stellar mass function is
only ~10^2 times lower at z=6 than at z=0. The difference between the black
hole and stellar mass function evolution is due to either rapid early star
formation which is not limited by radiation pressure as is the case for black
hole growth or inefficient black hole seeding. Our work predicts that the black
hole mass - stellar mass relation for a volume-limited sample of galaxies
declines rapidly at very high redshift. This is in contrast to the observed
increase at 4<z<6 from the local relation if one just studies the most massive
black holes.Comment: 16 pages, 10 figures, AJ in pres
Hydrolysis of ibuprofenoyl-CoA and other 2-APA-CoA esters by human acyl-CoA thioesterases-1 and -2 and their possible role in the chiral inversion of profens
TeV gamma-rays and neutrinos from photo-disintegration of nuclei in Cygnus OB2
TeV gamma-rays may provide significant information about high energy
astrophysical accelerators. Such gamma-rays can result from the
photo-de-excitation of PeV nuclei after their parents have undergone
photo-disintegration in an environment of ultraviolet photons. This process is
proposed as a candidate explanation of the recently discovered HEGRA source at
the edge of the Cygnus OB2 association. The Lyman-alpha background is provided
by the rich O and B stellar environment. It is found that (1) the HEGRA flux
can be obtained if there is efficient acceleration at the source of lower
energy nuclei; (2) the requirement that the Lorentz-boosted ultraviolet photons
can excite the Giant Dipole resonance implies a strong suppression of the
gamma-ray spectrum compared to an E_\gamma^{-2} behavior at energies \alt 1 TeV
(some of these energies will be probed by the upcoming GLAST mission); (3) a
TeV neutrino counterpart from neutron decay following helium
photo-disintegration will be observed at IceCube only if a major proportion of
the kinetic energy budget of the Cygnus OB2 association is expended in
accelerating nuclei.Comment: To be published in Phys. Rev.
Evaluating the health and economic impact of osteoarthritis pain in the workforce: results from the National Health and Wellness Survey
<p>Abstract</p> <p>Background</p> <p>There has been increasing recognition that osteoarthritis (OA) affects younger individuals who are still participants in the workforce, but there are only limited data on the contribution of OA pain to work productivity and other outcomes in an employed population. This study evaluated the impact of OA pain on healthcare resource utilization, productivity and costs in employed individuals.</p> <p>Methods</p> <p>Data were derived from the 2009 National Health and Wellness Survey. Univariable and multivariable analyses were used to characterize employed individuals (full-time, part-time, or self-employed) ≥20 years of age who were diagnosed with OA and had arthritis pain in the past month relative to employed individuals not diagnosed with OA or not experiencing arthritis pain in the past month. Work productivity was assessed using the Work Productivity and Activity Impairment (WPAI) questionnaire; health status was assessed using the physical (PCS) and mental component summary (MCS) scores from the SF-12v2 Health Survey and SF-6D health utilities; and healthcare utilization was evaluated by type and number of resources within the past 6 months. Direct and indirect costs were estimated and compared between the two cohorts.</p> <p>Results</p> <p>Individuals with OA pain were less likely to be employed. Relative to workers without OA pain (n = 37,599), the OA pain cohort (n = 2,173) was significantly older (mean age 52.1 ± 11.5 years vs 41.4 ± 13.2 years; <it>P </it>< 0.0001) and with a greater proportion of females (58.2% vs 45.9%; <it>P </it>< 0.0001). OA pain resulted in greater work impairment than among workers without OA pain (34.4% versus 17.8%; <it>P </it>< 0.0001), and was primarily due to presenteeism (impaired activity while at work). Health status, assessed both by the SF-12v2 and the SF-6D was significantly poorer among workers with OA pain (<it>P </it>< 0.0001), and healthcare resource utilization was significantly higher (<it>P </it>< 0.0001) than workers without OA pain. Total costs were higher in the OA pain cohort (8,175; <it>P </it>< 0.0001), driven by indirect costs that accounted for approximately 75% of total costs.</p> <p>Conclusions</p> <p>A substantial proportion of workers suffer from OA pain. After controlling for confounders, the impact of OA pain was significant, resulting in lower productivity and higher costs.</p
Activity pacing for osteoarthritis symptom management: study design and methodology of a randomized trial testing a tailored clinical approach using accelerometers for veterans and non-veterans
<p>Abstract</p> <p>Background</p> <p>Osteoarthritis (OA) is a prevalent chronic disease and a leading cause of disability in adults. For people with knee and hip OA, symptoms (e.g., pain and fatigue) can interfere with mobility and physical activity. Whereas symptom management is a cornerstone of treatment for knee and hip OA, limited evidence exists for behavioral interventions delivered by rehabilitation professionals within the context of clinical care that address how symptoms affect participation in daily activities. Activity pacing, a strategy in which people learn to preplan rest breaks to avoid symptom exacerbations, has been effective as part of multi-component interventions, but hasn't been tested as a stand-alone intervention in OA or as a tailored treatment using accelerometers. In a pilot study, we found that participants who underwent a tailored activity pacing intervention had reduced fatigue interference with daily activities. We are now conducting a full-scale trial.</p> <p>Methods/Design</p> <p>This paper provides a description of our methods and rationale for a trial that evaluates a tailored activity pacing intervention led by occupational therapists for adults with knee and hip OA. The intervention uses a wrist accelerometer worn during the baseline home monitoring period to glean recent symptom and physical activity patterns and to tailor activity pacing instruction based on how symptoms relate to physical activity. At 10 weeks and 6 months post baseline, we will examine the effectiveness of a tailored activity pacing intervention on fatigue, pain, and physical function compared to general activity pacing and usual care groups. We will also evaluate the effect of tailored activity pacing on physical activity (PA).</p> <p>Discussion</p> <p>Managing OA symptoms during daily life activity performance can be challenging to people with knee and hip OA, yet few clinical interventions address this issue. The activity pacing intervention tested in this trial is designed to help people modulate their activity levels and reduce symptom flares caused by too much or too little activity. As a result of this trial, we will be able to determine if activity pacing is more effective than usual care, and among the intervention groups, if an individually tailored approach improves fatigue and pain more than a general activity pacing approach.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01192516">NCT01192516</a></p
Ultraluminous Infrared Galaxies
Ever since their discovery in the 1970's, UltraLuminous InfraRed Galaxies
(ULIRGs; classically Lir>10^12Lsun) have fascinated astronomers with their
immense luminosities, and frustrated them due to their singularly opaque
nature, almost in equal measure. Over the last decade, however, comprehensive
observations from the X-ray through to the radio have produced a consensus
picture of local ULIRGs, showing that they are mergers between gas rich
galaxies, where the interaction triggers some combination of dust-enshrouded
starburst and AGN activity, with the starburst usually dominating. Very recent
results have thrown ULIRGs even further to the fore. Originally they were
thought of as little more than a local oddity, but the latest IR surveys have
shown that ULIRGs are vastly more numerous at high redshift, and tantalizing
suggestions of physical differences between high and low redshift ULIRGs hint
at differences in their formation modes and local environment. In this review
we look at recent progress on understanding the physics and evolution of local
ULIRGs, the contribution of high redshift ULIRGs to the cosmic infrared
background and the global history of star formation, and the role of ULIRGs as
diagnostics of the formation of massive galaxies and large-scale structures.Comment: Review article, published in "Astrophysics Update 2 - topical and
timely reviews on astronomy and astrophysics". Ed. John W. Mason.
Springer/Praxis books. ISBN: 3-540-30312-X. 53 pages, 5 figures. Higher
quality figures available on reques
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