3,251 research outputs found
Augmenting the Human Capital Earnings Equation with Measures of Where People Work
We augment standard log earnings equations for workers in US manufacturing with variables reflecting measured and unmeasured attributes of their employer. Using panel employee-establishment data, we find that establishment-level employment, education of coworkers, capital equipment per worker, and firm-level R&D intensity affects earnings substantially. Unobserved characteristics of employers captured by employer fixed effects also contribute to the variance of log earnings, although less than unobserved characteristics of individuals captured by individual fixed effects. The observed and unobserved measures of employers mediate the effects of individual characteristics on earnings and increase earnings inequality through sorting of workers among establishments
Searching for an Intermediate Mass Black Hole in the Blue Compact Dwarf galaxy MRK 996
The possibility is explored that accretion on an intermediate mass black hole
contributes to the ionisation of the interstellar medium of the Compact Blue
Dwarf galaxy MRK996. Chandra observations set tight upper limits (99.7 per cent
confidence level) in both the X-ray luminosity of the posited AGN,
Lx(2-10keV)<3e40erg/s, and the black hole mass, <1e4/\lambda Msolar, where
\lambda, is the Eddington ratio. The X-ray luminosity upper limit is
insufficient to explain the high ionisation line [OIV]25.89\mu m, which is
observed in the mid-infrared spectrum of the MRK996 and is proposed as evidence
for AGN activity. This indicates that shocks associated with supernovae
explosions and winds of young stars must be responsible for this line. It is
also found that the properties of the diffuse X-ray emission of MRK996 are
consistent with this scenario, thereby providing direct evidence for shocks
that heat the galaxy's interstellar medium and contribute to its ionisation.Comment: Submitted to MNRA
The Host Galaxy and Central Engine of the Dwarf AGN POX 52
We present new multi-wavelength observations of the dwarf Seyfert 1 galaxy
POX 52 in order to investigate the properties of the host galaxy and the active
nucleus, and to examine the mass of its black hole, previously estimated to be
~ 10^5 M_sun. Hubble Space Telescope ACS/HRC images show that the host galaxy
has a dwarf elliptical morphology (M_I = -18.4 mag, Sersic index n = 4.3) with
no detected disk component or spiral structure, confirming previous results
from ground-based imaging. X-ray observations from both Chandra and XMM show
strong (factor of 2) variability over timescales as short as 500 s, as well as
a dramatic decrease in the absorbing column density over a 9 month period. We
attribute this change to a partial covering absorber, with a 94% covering
fraction and N_H = 58^{+8.4}_{-9.2} * 10^21 cm^-2, that moved out of the line
of sight in between the XMM and Chandra observations. Combining these data with
observations from the VLA, Spitzer, and archival data from 2MASS and GALEX, we
examine the spectral energy distribution (SED) of the active nucleus. Its shape
is broadly similar to typical radio-quiet quasar SEDs, despite the very low
bolometric luminosity of L_bol = 1.3 * 10^43 ergs/s. Finally, we compare black
hole mass estimators including methods based on X-ray variability, and optical
scaling relations using the broad H-beta line width and AGN continuum
luminosity, finding a range of black hole mass from all methods to be M_bh =
(2.2-4.2) * 10^5 M_sun, with an Eddington ratio of L_bol/L_edd = 0.2-0.5.Comment: 19 pages, 16 figures, accepted for publication in Ap
Predicting Postfire Sediment Yields of Small Steep Catchments Using Airborne Lidar Differencing
Predicting sediment yield from recently burned areas remains a challenge but is important for hazard and resource management as wildfire impacts increase. Here we use lidar-based monitoring of two fires in southern California, USA to study the movement of sediment during pre-rainfall periods and postfire periods of flooding and debris flows over multiple storm events. Using a data-driven approach, we examine the relative importance of terrain, vegetation, burn severity, and rainfall amounts through time on sediment yield. We show that incipient fire-activated dry sediment loading and pre-fire colluvium were rapidly flushed out by debris flows and floods but continued erosion occurred later in the season from soil erosion and, in ∼9% of catchments, from shallow landslides. Based on these observations, we develop random forest regression models to predict dry ravel and incipient runoff-driven sediment yield applicable to small steep headwater catchments in southern California
Personalised anti-inflammatory therapy for bronchiectasis and cystic fibrosis:selecting patients for controlled trials of neutrophil elastase inhibition
Background
Neutrophil elastase (NE) has been linked to lung neutrophil dysfunction in bronchiectasis and cystic fibrosis (CF), making NE inhibition a potential therapeutic target. NE inhibitor trials have given mixed result perhaps because not all patients have elevated airway NE activity.
Methods
We tested whether a single baseline sputum NE measurement or a combination of clinical parameters could enrich patient populations with elevated NE activity for “personalised medicine”. Intra- and interindividual variations of total and active NE levels in induced sputum from patients with CF or bronchiectasis were monitored over 14 days. Patients with established CF and bronchiectasis (n=5 per group) were recruited. NE was measured using three different methods: one total and two active NE assays. Subsequently, we analysed the association between clinical parameters and NE from a large bronchiectasis cohort study (n=381).
Results
All three assays showed a high degree of day-to-day variability (0–233% over 14 days). There were strong correlations found between all assays (p<0.0001). Despite high day-to-day variability, patients could be stratified into “high” or “low” groups based on moderate cut-off levels. In the bronchiectasis cohort study, factors most associated with high sputum NE levels were: Pseudomonas aeruginosa infection (β-estimate 11.5, 95% CI −6.0–29.0), sputum colour (β-estimate 10.4, 95% CI 4.3–16.6), Medical Research Council dyspnoea score (β-estimate 6.4, 95% CI 1.4–11.4) and exacerbation history (β-estimate 3.4, 95% CI 1.4–5.3). Collectively, P. aeruginosa infection, sputum colour and exacerbation frequency provided the greatest specificity for “high” NE (98.7%, 95% CI 7.0–99.6%).
Conclusion
These results show that patients with bronchiectasis and CF can be effectively divided into “high” or “low” groups, based on sputum NE assays or clinical inclusion criteria
Negotiating identities: ethnicity and social relations in a young offenders' institution
This article explores the situated nature of male prisoner identities in the late modern British context, using the contrasting theoretical frames of Sykes's (1958) indigenous model and Jacobs' (1979) importation model of prisoner subcultures and social relations. Drawing on eight months of ethnographic fieldwork in an ethnically, religiously and nationally diverse young offenders institution, consideration is given to how prisoners manage and negotiate difference, exploring the contours of racialization and racism which can operate in ambiguous and contradictory ways. Sociological understandings of identity, ethnicity, racialization and racism are used to inform a more empirically grounded theoretical criminology
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BRAIN Initiative: Cutting-Edge Tools and Resources for the Community.
The overarching goal of the NIH BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative is to advance the understanding of healthy and diseased brain circuit function through technological innovation. Core principles for this goal include the validation and dissemination of the myriad innovative technologies, tools, methods, and resources emerging from BRAIN-funded research. Innovators, BRAIN funding agencies, and non-Federal partners are working together to develop strategies for making these products usable, available, and accessible to the scientific community. Here, we describe several early strategies for supporting the dissemination of BRAIN technologies. We aim to invigorate a dialogue with the neuroscience research and funding community, interdisciplinary collaborators, and trainees about the existing and future opportunities for cultivating groundbreaking research products into mature, integrated, and adaptable research systems. Along with the accompanying Society for Neuroscience 2019 Mini-Symposium, "BRAIN Initiative: Cutting-Edge Tools and Resources for the Community," we spotlight the work of several BRAIN investigator teams who are making progress toward providing tools, technologies, and services for the neuroscience community. These tools access neural circuits at multiple levels of analysis, from subcellular composition to brain-wide network connectivity, including the following: integrated systems for EM- and florescence-based connectomics, advances in immunolabeling capabilities, and resources for recording and analyzing functional connectivity. Investigators describe how the resources they provide to the community will contribute to achieving the goals of the NIH BRAIN Initiative. Finally, in addition to celebrating the contributions of these BRAIN-funded investigators, the Mini-Symposium will illustrate the broader diversity of BRAIN Initiative investments in cutting-edge technologies and resources
The InfraRed Imaging Spectrograph (IRIS) for TMT: latest science cases and simulations
The Thirty Meter Telescope (TMT) first light instrument IRIS (Infrared
Imaging Spectrograph) will complete its preliminary design phase in 2016. The
IRIS instrument design includes a near-infrared (0.85 - 2.4 micron) integral
field spectrograph (IFS) and imager that are able to conduct simultaneous
diffraction-limited observations behind the advanced adaptive optics system
NFIRAOS. The IRIS science cases have continued to be developed and new science
studies have been investigated to aid in technical performance and design
requirements. In this development phase, the IRIS science team has paid
particular attention to the selection of filters, gratings, sensitivities of
the entire system, and science cases that will benefit from the parallel mode
of the IFS and imaging camera. We present new science cases for IRIS using the
latest end-to-end data simulator on the following topics: Solar System bodies,
the Galactic center, active galactic nuclei (AGN), and distant
gravitationally-lensed galaxies. We then briefly discuss the necessity of an
advanced data management system and data reduction pipeline.Comment: 15 pages, 7 figures, SPIE (2016) 9909-0
Derivation and internal validation of an equation for albumin-adjusted calcium
YesFunding provided by the Open Access Authors Fund
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