951 research outputs found
Local Swift-BAT active galactic nuclei prefer circumnuclear star formation
We use Herschel data to analyze the size of the far-infrared 70micron
emission for z<0.06 local samples of 277 hosts of Swift-BAT selected active
galactic nuclei (AGN), and 515 comparison galaxies that are not detected by
BAT. For modest far-infrared luminosities 8.5<log(LFIR)<10.5, we find large
scatter of half light radii Re70 for both populations, but a typical Re70 <~ 1
kpc for the BAT hosts that is only half that of comparison galaxies of same
far-infrared luminosity. The result mostly reflects a more compact distribution
of star formation (and hence gas) in the AGN hosts, but compact AGN heated dust
may contribute in some extremely AGN-dominated systems. Our findings are in
support of an AGN-host coevolution where accretion onto the central black hole
and star formation are fed from the same gas reservoir, with more efficient
black hole feeding if that reservoir is more concentrated. The significant
scatter in the far-infrared sizes emphasizes that we are mostly probing spatial
scales much larger than those of actual accretion, and that rapid accretion
variations can smear the distinction between the AGN and comparison categories.
Large samples are hence needed to detect structural differences that favour
feeding of the black hole. No size difference AGN host vs. comparison galaxies
is observed at higher far-infrared luminosities log(LFIR)>10.5 (star formation
rates >~ 6 Msun/yr), possibly because these are typically reached in more
compact regions in the first place.Comment: 7 pages, 3 figures, accepted for publication in Astronomy &
Astrophysic
The Ionized Gas in Nearby Galaxies as Traced by the [NII] 122 and 205 \mu m Transitions
The [NII] 122 and 205 \mu m transitions are powerful tracers of the ionized
gas in the interstellar medium. By combining data from 21 galaxies selected
from the Herschel KINGFISH and Beyond the Peak surveys, we have compiled 141
spatially resolved regions with a typical size of ~1 kiloparsec, with
observations of both [NII] far-infrared lines. We measure [NII] 122/205 line
ratios in the ~0.6-6 range, which corresponds to electron gas densities
~1-300 cm, with a median value of =30 cm. Variations in
the electron density within individual galaxies can be as a high as a factor of
~50, frequently with strong radial gradients. We find that increases as a
function of infrared color, dust-weighted mean starlight intensity, and star
formation rate surface density (). As the intensity of the [NII]
transitions is related to the ionizing photon flux, we investigate their
reliability as tracers of the star formation rate (SFR). We derive relations
between the [NII] emission and SFR in the low-density limit and in the case of
a log-normal distribution of densities. The scatter in the correlation between
[NII] surface brightness and can be understood as a property of
the distribution. For regions with close to or higher than the
[NII] line critical densities, the low-density limit [NII]-based SFR
calibration systematically underestimates the SFR since [NII] emission is
collisionally quenched. Finally, we investigate the relation between [NII]
emission, SFR, and by comparing our observations to predictions from the
MAPPINGS-III code.Comment: 18 pages, 9 figures, accepted for publication in The Astrophysical
Journa
Piroxicam fails to reduce myocellular enzyme leakage and delayed onset muscle soreness induced by isokinetic eccentric exercise
To test the hypothesis that delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of prostaglandin E2 (PGE2), ten healthy male subjects were studied. Using a double-blind randomized crossover design, each subject performed two isokinetic tests separated by a period of at least 6 weeks: once with placebo, and once with piroxicam (Feldene®). They were given one capsule containing either placebo or piroxicam (20 mg) per day for 6 days with initial doses given starting 3 days prior to isokinetic testing. Exercise consisted of eight stages of five maximal contractions of the knee extensor and flexor muscle groups of both legs separated by 1 min rest phases, on a Kin Trex device at 60°/s angular velocity. The subjective presence and intensity of DOMS were evaluated using a visual analogue scale immediately after, and 24 and 48 h after each test. The mean plasma concentration of PGE2 measured at rest and after exercise was significantly lower in the group treated with piroxicam (p < 0.05). However, statistical analysis (two-way ANOVA test) revealed that exercise did not cause any significant change of mean plasma PGE2 over time in either of the two groups. Eccentric work was followed by severe muscle pain in extensor and flexor muscle groups. Maximal soreness was noted 48 h postexercise. Serum creatine kinase activity and the serum concentration of myoglobin increased significantly, and reached peak values 48 h after exercise in both experimental conditions (p < 0.001). By paired t-test, it appeared that there were no significant differences in the serum levels of these two markers of muscle damage between the two groups at any time point. We conclude that: (1) oral administration of piroxicam fails to reduce muscle damage and DOMS caused by strenuous eccentric exercise; and (2) the hypothetical role of increased PGE2 production in eccentric exercise-induced muscle damage, DOMS, and reduced isokinetic performance is not substantiated by the present results
Dreaming of drams: Authenticity in Scottish whisky tourism as an expression of unresolved Habermasian rationalities
In this paper, the production of whisky tourism at both independently owned and corporately owned distilleries in Scotland is explored by focusing on four examples (Arran, Glengoyne, Glenturret and Bruichladdich). In particular, claims of authenticity and Scottishness of Scottish whiskies through commercial materials, case studies, website-forum discussions and 'independent' writing about such whisky are analysed. It is argued that the globalisation and commodification of whisky and whisky tourism, and the communicative backlash to these trends typified by the search for authenticity, is representative of a Habermasian struggle between two irreconcilable rationalities. This paper will demonstrate that the meaning and purpose of leisure can be understood through such explorations of the tension between the instrumentality of commodification and the freedom of individuals to locate their own leisure lives in the lifeworld that remains. © 2011 Taylor & Francis
Quality control of leather by terahertz time domain spectroscopy
We use terahertz time-domain spectroscopy combined with effective-medium theory to measure moisture content and thickness of leather simultaneously. These results demonstrate that this method could become a standard quality control test for the industrial tanning process
GenoList: an integrated environment for comparative analysis of microbial genomes
The multitude of bacterial genome sequences being determined has generated new requirements regarding the development of databases and graphical interfaces: these are needed to organize and retrieve biological information from the comparison of large sets of genomes. GenoList (http://genolist.pasteur.fr/GenoList) is an integrated environment dedicated to querying and analyzing genome data from bacterial species. GenoList inherits from the SubtiList database and web server, the reference data resource for the Bacillus subtilis genome. The data model was extended to hold information about relationships between genomes (e.g. protein families). The web user interface was designed to primarily take into account biologists’ needs and modes of operation. Along with standard query and browsing capabilities, comparative genomics facilities are available, including subtractive proteome analysis. One key feature is the integration of the many tools accessible in the environment. As an example, it is straightforward to identify the genes that are specific to a group of bacteria, export them as a tab-separated list, get their protein sequences and run a multiple alignment on a subset of these sequences
Climate change-driven coastal erosion modelling in temperate sandy beaches: Methods and uncertainty treatment
Developing future projections of shoreline change requires a good understanding of the driving coastal processes. These processes result primarily from the combination of mean sea level, waves, storm surges and tides, which are affected by global and regional climate change, and whose uncertainty increases with time. This paper reviews the current state of the art of methods used to model climate change-induced coastal erosion focusing on how climate change-related drivers and the associated uncertainty are considered. We identify research gaps, describe and analyse the key components of a comprehensive framework to derive future estimates of shoreline change and make suggestions for good practice. Within the scope of the review, we find that although significant progress has been made over the last decade, most of the studies limit uncertainty sampling to considering ranges of variation of forcing variables and ensembles of emissions scenarios, and applications with high level of probabilistic development remain few. Further research is necessary to fully (a) incorporate projected time series of coastal drivers into the erosion models, including bias correction; (b) sufficiently sample the uncertainty associated with each step of the top-down approach, including the consideration of different emission scenarios, inter- and intra-model variability, and multiple runs of erosion models or model ensembles; and (c) reduce uncertainty in shoreline change estimates by developing better datasets and model parameterisations, and progressing in detection and attribution
Exploiting X-ray induced anisotropic lattice changes to improve intensity extraction in protein powder diffraction: Application to heavy atom detection
X-ray induced anisotropic variations of cell parameters in porcine pancreatic elastase (PPE) were used in a multi-Pawley refinement in order to improve the deconvolution of overlapping peaks occurring in the high-angle region of the powder pattern. The benefit of combining scans is demonstrated by an improvement in the quality of the isomorphous difference Patterson maps used to detect the positions of heavy atoms in a uranyl derivative of PPE
Genetic diversity of CHC22 clathrin impacts its function in glucose metabolism
CHC22 clathrin plays a key role in intracellular membrane traffic of the insulin-responsive glucose transporter GLUT4 in humans. We performed population genetic and phylogenetic analyses of the CHC22-encoding CLTCL1 gene, revealing independent gene loss in at least two vertebrate lineages, after arising from gene duplication. All vertebrates retained the paralogous CLTC gene encoding CHC17 clathrin, which mediates endocytosis. For vertebrates retaining CLTCL1, strong evidence for purifying selection supports CHC22 functionality. All human populations maintained two high frequency CLTCL1 allelic variants, encoding either methionine or valine at position 1316. Functional studies indicated that CHC22-V1316, which is more frequent in farming populations than in hunter-gatherers, has different cellular dynamics than M1316-CHC22 and is less effective at controlling GLUT4 membrane traffic, altering its insulin-regulated response. These analyses suggest that ancestral human dietary change influenced selection of allotypes that affect CHC22’s role in metabolism and have potential to differentially influence the human insulin response
NEOWISE Observations of Near-Earth Objects: Preliminary Results
With the NEOWISE portion of the \emph{Wide-field Infrared Survey Explorer}
(WISE) project, we have carried out a highly uniform survey of the near-Earth
object (NEO) population at thermal infrared wavelengths ranging from 3 to 22
m, allowing us to refine estimates of their numbers, sizes, and albedos.
The NEOWISE survey detected NEOs the same way whether they were previously
known or not, subject to the availability of ground-based follow-up
observations, resulting in the discovery of more than 130 new NEOs. The
survey's uniformity in sensitivity, observing cadence, and image quality have
permitted extrapolation of the 428 near-Earth asteroids (NEAs) detected by
NEOWISE during the fully cryogenic portion of the WISE mission to the larger
population. We find that there are 98119 NEAs larger than 1 km and
20,5003000 NEAs larger than 100 m. We show that the Spaceguard goal of
detecting 90% of all 1 km NEAs has been met, and that the cumulative size
distribution is best represented by a broken power law with a slope of
1.320.14 below 1.5 km. This power law slope produces 1,900
NEAs with 140 m. Although previous studies predict another break in the
cumulative size distribution below 50-100 m, resulting in an increase in
the number of NEOs in this size range and smaller, we did not detect enough
objects to comment on this increase. The overall number for the NEA population
between 100-1000 m are lower than previous estimates. The numbers of near-Earth
comets will be the subject of future work.Comment: Accepted to Ap
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