20,301 research outputs found
Heterotrophic bacteria exhibit a wide range of rates of extracellular production and decay of hydrogen peroxide
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bond, R. J., Hansel, C. M., & Voelker, B. M. Heterotrophic bacteria exhibit a wide range of rates of extracellular production and decay of hydrogen peroxide. Frontiers in Marine Science, 7, (2020): 72, doi:10.3389/fmars.2020.00072.Bacteria have been implicated as both a source and sink of hydrogen peroxide (H2O2), a reactive oxygen species which can both impact microbial growth and participate in the geochemical cycling of trace metals and carbon in natural waters. In this study, simultaneous H2O2 production and decay by twelve species of heterotrophic bacteria were evaluated in both batch and flow-through incubations. While wide species-to-species variability of cell-normalized H2O2 decay rate coefficients [2 Ă 10â8 to 5 Ă 10â6 hrâ1 (cell mLâ1)â1] was observed, these rate coefficients were relatively consistent for a given bacterial species. By contrast, observed production rates (below detection limit to 3 Ă 102 amol cellâ1 hrâ1) were more variable even for the same species. Variations based on incubation conditions in some bacterial strains suggest that external conditions may impact extracellular H2O2 levels either through increased extracellular production or leakage of intracellular H2O2. Comparison of H2O2 production rates to previously determined superoxide (O2â) production rates suggests that O2â and H2O2 production are not necessarily linked. Rates measured in this study indicate that bacteria could account for a majority of H2O2 decay observed in aqueous systems but likely only make a modest contribution to dark H2O2 production.This research was supported by NSF grant OCE-1131734/1246174 to BV and CH
Views of healthcare professionals to linkage of routinely collected healthcare data : a systematic review
Peer reviewedPublisher PD
The power spectrum of galaxies in the 2dF 100k redshift survey
We compute the real-space power spectrum and the redshift-space distortions
of galaxies in the 2dF 100k galaxy redshift survey using pseudo-Karhunen-Loeve
eigenmodes and the stochastic bias formalism. Our results agree well with those
published by the 2dFGRS team, and have the added advantage of producing
easy-to-interpret uncorrelated minimum-variance measurements of the
galaxy-galaxy, galaxy-velocity and velocity-velocity power spectra in 27
k-bands, with narrow and well-behaved window functions in the range 0.01h/Mpc <
k < 0.8h/Mpc. We find no significant detection of baryonic wiggles, although
our results are consistent with a standard flat Omega_Lambda=0.7
``concordance'' model and previous tantalizing hints of baryonic oscillations.
We measure the galaxy-matter correlation coefficient r > 0.4 and the
redshift-distortion parameter beta=0.49+/-0.16 for r=1 (beta=0.47+/- 0.16
without finger-of-god compression). Since this is an apparent-magnitude limited
sample, luminosity-dependent bias may cause a slight red-tilt in the power
spectum. A battery of systematic error tests indicate that the survey is not
only impressive in size, but also unusually clean, free of systematic errors at
the level to which our tests are sensitive. Our measurements and window
functions are available at http://www.hep.upenn.edu/~max/2df.html together with
the survey mask, radial selection function and uniform subsample of the survey
that we have constructed.Comment: Replaced to match accepted MNRAS version, with new radial/angular
systematics plot and sigma8 typo corrected. High-res figures, power spectra,
windows and our uniform galaxy subsample with mask at
http://www.hep.upenn.edu/~max/2df.html or from [email protected]. 26
journal pages, 28 fig
Power Spectrum Estimators For Large CMB Datasets
Forthcoming high-resolution observations of the Cosmic Microwave Background
(CMB) radiation will generate datasets many orders of magnitude larger than
have been obtained to date. The size and complexity of such datasets presents a
very serious challenge to analysing them with existing or anticipated
computers. Here we present an investigation of the currently favored algorithm
for obtaining the power spectrum from a sky-temperature map --- the quadratic
estimator. We show that, whilst improving on direct evaluation of the
likelihood function, current implementations still inherently scale as the
equivalent of the cube of the number of pixels or worse, and demonstrate the
critical importance of choosing the right implementation for a particular
dataset.Comment: 8 pages LATEX, no figures, corrected misaligned columns in table
Inhomogeneous reionization and the polarization of the cosmic microwave background
In a universe with inhomogeneous reionization, the ionized patches create a
second order signal in the cosmic microwave background polarization anisotropy.
This signal originates in the coupling of the free electron fluctuation to the
quadruple moment of the temperature anisotropy. We examine the contribution
from a simple inhomogeneous reionization model and find that the signal from
such a process is below the detectable limits of the Planck Surveyor mission.
However t he signal is above the fundamental uncertainty limit from cosmic
variance, so th at a future detection with a high accuracy experiment on
sub-arcminute scales is possible.Comment: 10 pages, 2 eps figures, final version accepted for publication in
ApJ Letter
Smoking and intention to quit in deprived areas of Glasgow: is it related to housing improvements and neighbourhood regeneration because of improved mental health?
Background: People living in areas of multiple deprivation are more likely to smoke and less likely to quit smoking. This study examines the effect on smoking and intention to quit smoking for those who have experienced housing improvements (HI) in deprived areas of Glasgow, UK, and investigates whether such effects can be explained by improved mental health.
Methods: Quasi-experimental, 2-year longitudinal study, comparing residentsâ smoking and intention to quit smoking for HI group (n=545) with non-HI group (n=517), adjusting for baseline (2006) sociodemographic factors and smoking status. SF-12 mental health scores were used to assess mental health, along with self-reported experience of, and General Practitioner (GP) consultations for, anxiety and depression in the last 12 months.
Results: There was no relationship between smoking and HI, adjusting for baseline rates (OR=0.97, 95% CI 0.57 to 1.67, p=0.918). We found an association between intention to quit and HI, which remained significant after adjusting for sociodemographics and previous intention to quit (OR 2.16, 95% CI 1.12 to 4.16, p=0.022). We found no consistent evidence that this association was attenuated by improvement in our three mental health measures.
Conclusions: Providing residents in disadvantaged areas with better housing may prompt them to consider quitting smoking. However, few people actually quit, indicating that residential improvements or changes to the physical environment may not be sufficient drivers of personal behavioural change. It would make sense to link health services to housing regeneration projects to support changes in health behaviours at a time when environmental change appears to make behavioural change more likely
Application of XFaster power spectrum and likelihood estimator to Planck
We develop the XFaster Cosmic Microwave Background (CMB) temperature and
polarization anisotropy power spectrum and likelihood technique for the Planck
CMB satellite mission. We give an overview of this estimator and its current
implementation and present the results of applying this algorithm to simulated
Planck data. We show that it can accurately extract the power spectrum of
Planck data for the high-l multipoles range. We compare the XFaster
approximation for the likelihood to other high-l likelihood approximations such
as Gaussian and Offset Lognormal and a low-l pixel-based likelihood. We show
that the XFaster likelihood is not only accurate at high-l, but also performs
well at moderately low multipoles. We also present results for cosmological
parameter Markov Chain Monte Carlo estimation with the XFaster likelihood. As
long as the low-l polarization and temperature power are properly accounted
for, e.g., by adding an adequate low-l likelihood ingredient, the input
parameters are recovered to a high level of accuracy.Comment: 25 pages, 20 figures, updated to reflect published version: slightly
extended account of XFaster technique, added improved plots and minor
corrections. Accepted for publication in MNRA
Cosmic Microwave Background Anisotropy Window Functions Revisited
The primary results of most observations of cosmic microwave background (CMB)
anisotropy are estimates of the angular power spectrum averaged through some
broad band, called band-powers. These estimates are in turn what are used to
produce constraints on cosmological parameters due to all CMB observations.
Essential to this estimation of cosmological parameters is the calculation of
the expected band-power for a given experiment, given a theoretical power
spectrum. Here we derive the "band power" window function which should be used
for this calculation, and point out that it is not equivalent to the window
function used to calculate the variance. This important distinction has been
absent from much of the literature: the variance window function is often used
as the band-power window function. We discuss the validity of this assumed
equivalence, the role of window functions for experiments that constrain the
power in {\it multiple} bands, and summarize a prescription for reporting
experimental results. The analysis methods detailed here are applied in a
companion paper to three years of data from the Medium Scale Anisotropy
Measurement.Comment: 5 pages, 1 included .eps figure, PRD in press---final published
versio
The effect of an internet option and single-sided printing format to increase the response rate to a population-based study : a randomized controlled trial
Acknowledgements We would like to thank the Institute of Applied Health Sciences (IAHS) at the University of Aberdeen for funding the PhD studentship of EF. Furthermore, we would like to thank everyone who was involved in the study, including Professor Sir Lewis Ritchie (Director of Public Health, NHS Grampian), John Lemon (University of Aberdeen), Dr. Fiona Garton (University of Aberdeen) and the Aberdeen Service User Group. Lastly, we would like to acknowledge all data entry clerks (Maxx Livingstone, Rory Macfarlane, Georgia Mannion-Krase and Hazel Reilly) and participants of the study.Peer reviewedPublisher PD
The Cosmic Microwave Background and Inflation Parameters
We review the currrent cosmic parameter determinations of relevance to
inflation using the WMAP-1year, Boomerang, CBI, Acbar and other CMB data. The
basic steps in the pipelines which determine the bandpowers from the raw data
from which these estimations are made are summarized. We forecast how the
precision is likely to improve with more years of WMAP in combination with
future ground-based experiments and with Planck. We address whether the current
data indicates strong breaking from uniform acceleration through the relatively
small region of the inflaton potential that the CMB probes, manifest in the
much-discussed running spectral index or in even more radical braking/breaking
scenarios. Although some weak ``anomalies'' appear in the current data, the
statistical case is not there. However increased precision, at the high
multipole end and with polarization measurements, will significantly curtail
current freedom.Comment: 24 pages, 10 figures, 2 tables, Int. J. Theor. Phys. 2004, ed. E.
Verdaguer, "Peyresq Physics 8", "The Early Universe: Confronting theory with
observations" (June 21-27, 2003
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