957 research outputs found
Unbiased Cluster Lens Reconstruction
Weak lensing observations measure the shear field and hence the gradient of
the dimensionless surface density . We present several new algorithms
to recover {}from shear estimates on a finite region and compare how
they perform with realistically noisy data. The reconstruction methods studied
here are divided into 2 classes: direct reconstruction and regularized
inversion. Direct reconstruction techniques express as a 2D integral
of the shear field. This yields an estimator for as a discrete sum
over background galaxy ellipticities which is straightforward to implement, and
allows a simple estimate of the noise. We study 3 types of direct
reconstruction methods: 1) -estimators that measure the surface density
at any given target point relative to the mean value in a reference region 2) a
method that explicitly attempts to minimize the rotational part of that is due to noise and 3) a novel, exact Fourier-space inverse
gradient operator. We also develop two `regularized maximum likelihood'
methods, one of which employs the conventional discrete Laplacian operator as a
regularizer and the other uses regularization of all components in Fourier
space. We compare the performance of all the estimators by means of simulations
and noise power analysis. A general feature of these unbiased methods is an
enhancement of the low frequency power which, for some of the methods, can be
quite severe. We find the best performance is provided by the maximum
likelihood method with Fourier space regularization although some of the other
methods perform almost as well.Comment: 37 pages, latex, figures include
Mainstreaming the Disability Equality Duty and the impact on public authorities' working practices
Implemented as part of the 2005 amendments to the Disability Equality Act, the Disability Equality Duty (DED) placed new and important demands on public sector bodies. All such organisations are required to develop policies and working practices which actively promote the equality of disabled people as employees, consumers or visitors. The promotion of equality has to be proactive as opposed to reactive and must be mainstreamed into the normal day to day activities of organisational working practices. Whilst the DED follows on from the framework of previous anti-discrimination legislation set in place over the last fifteen years, it represents a significant change in equality legislation, demands that public sector bodies instigate fundamental changes in their approach towards disability. This article reports on the initial stages of the implementation process of the DED across a range of public sector organisations in England, focussing in particular on how this policy has impacted on mainstreaming. Discussion shows that although organisations show awareness of mainstreaming and its implications for disability equality, there is limited evidence to suggest that the public sector has fully embraced this agenda
The Evolution and Environments of X-ray Emitting Active Galactic Nuclei in High-Redshift Large-Scale Structures
We use deep Chandra imaging and an extensive optical spectroscopy campaign on
the Keck 10-m telescopes to study the properties of X-ray point sources in five
large-scale structures at redshifts of z ~ 0.7-0.9. We first study X-ray point
sources using the statistical measure of cumulative source counts, finding that
the measured overdensities are consistent with previous results, but we
recommend caution in overestimating the precision of the technique. Optical
spectroscopy of objects matched to X-ray point sources confirms a total of 27
AGN within the five structures, and we find that their host galaxies tend to be
located away from dense cluster cores. More than 36% of host galaxies are
located in the `green valley', which suggests they are a transitional
population. Based on analysis of OII and Hd line strengths, the average
spectral properties of the AGN host galaxies in all structures indicate either
on-going star formation or a starburst within ~ 1 Gyr, and the host galaxies
are younger than the average galaxy in the parent population. These results
indicate a clear connection between starburst and nuclear activity. We use
composite spectra of the spectroscopically confirmed members in each structure
to separate them based on a measure of the overall evolutionary state of their
constituent galaxies. We define structures as having more evolved populations
if their average galaxy has lower EW(OII) and EW(Hd). The AGN in the more
evolved structures have lower rest-frame 0.5-8 keV X-ray luminosities (all
below 10^43.3 erg s^-1) and longer times since a starburst than those in the
less evolved structures, suggesting that the peak of both star formation and
AGN activity has occurred at earlier times. With the wide range of evolutionary
states and timeframes in the structures, we use our results to analyze the
evolution of X-ray AGN and evaluate potential triggering mechanisms.Comment: 29 pages, 13 figure
Enhancing the reporting of implementation research
In the 10 years since the inception of Implementation Science, we have witnessed a continued rise in the number of submissions received, reflecting the continued global interest in methods to enhance the uptake of research findings into healthcare practice and policy. We receive over 750 submissions annually, and there is now a large gap between what is submitted and what gets published. In this editorial, we restate the journal scope and current boundaries. We also identify some specific reporting issues that if addressed will help enhance the scientific reporting quality and transparency of the manuscripts we receive. We hope that this editorial acts as a further guide to researchers seeking to publish their work in Implementation Science
Volatile organic compound mixing ratios above Beijing in November and December 2016
Volatile organic compounds (VOCs) are emitted into the atmosphere from vegetation and anthropogenic
sources such as fossil fuel combustion, biomass burning and the evaporation of petroleum products. These
compounds play an important role in the chemistry of the lower atmosphere through secondary organic aerosol
(SOA) formation and facilitating the formation of tropospheric ozone. As well as their indirect impact on human
health via the formation of ozone and SOA, some VOCs, including benzene, directly affect human health adversely.
Here we report VOC mixing ratios measured in Beijing during a 5 week intensive field campaign from the
7th November to the 10th December 2016. This work was carried out as part of the Sources and Emissions
of Air Pollutants in Beijing (AIRPOLL-Beijing) work project within the Air Pollution and Human Health in
a Developing Megacity (APHH-Beijing) research programme. APHH is a large multi-institutional study which
aims to record the concentrations and identify the sources of urban air pollutants in Beijing, determine exposure,
understand their effects on human health, and to identify solutions.
VOC mixing ratios were recorded using a Proton Transfer Reaction-Time of Flight-Mass Spectrometer
(PTR-ToF-MS, Ionicon Analytik) and a Selected Ion Flow Tube-Mass Spectrometer (SIFT-MS, SYFT Technologies).
During the measurement period Beijing was subject to multiple pollution events that alternated with periods
of relatively good air quality, allowing the VOCs within the polluted air masses to be identified and quantified.
VOCs were sampled at 102 m with additional gradient measurements made at 3, 15, 32 and 64 m providing a
vertical profile of VOC mixing ratios. Mixing ratios of methanol, acetonitrile, acetaldehyde, acetone, isoprene and
aromatics species will be reported together with a discussion of potential sources. Comparisons will then be drawn
with other large cities
PB1-F2 Proteins from H5N1 and 20th Century Pandemic Influenza Viruses Cause Immunopathology
With the recent emergence of a novel pandemic strain, there is presently intense interest in understanding the molecular signatures of virulence of influenza viruses. PB1-F2 proteins from epidemiologically important influenza A virus strains were studied to determine their function and contribution to virulence. Using 27-mer peptides derived from the C-terminal sequence of PB1-F2 and chimeric viruses engineered on a common background, we demonstrated that induction of cell death through PB1-F2 is dependent upon BAK/BAX mediated cytochrome c release from mitochondria. This function was specific for the PB1-F2 protein of A/Puerto Rico/8/34 and was not seen using PB1-F2 peptides derived from past pandemic strains. However, PB1-F2 proteins from the three pandemic strains of the 20th century and a highly pathogenic strain of the H5N1 subtype were shown to enhance the lung inflammatory response resulting in increased pathology. Recently circulating seasonal influenza A strains were not capable of this pro-inflammatory function, having lost the PB1-F2 protein's immunostimulatory activity through truncation or mutation during adaptation in humans. These data suggest that the PB1-F2 protein contributes to the virulence of pandemic strains when the PB1 gene segment is recently derived from the avian reservoir
Moving prison health promotion along: Towards an integrative framework for action to develop health promotion and tackle the social determinants of health
The majority of prisoners are drawn from deprived circumstances with a range of health and social needs. The current focus within ‘prison health’ does not, and cannot, given its predominant medical model, adequately address the current health and well-being needs of offenders. Adopting a social model of health is more likely to address the wide range of health issues faced by offenders and thus lead to better rehabilitation outcomes. At the same time, broader action at governmental level is required to address the social determinants of health (poverty, unemployment and educational attainment) that marginalise populations and increase the likelihood of criminal activities. Within prison, there is more that can be done to promote prisoners’ health if a move away from a solely curative, medical model is facilitated, towards a preventive perspective designed to promote positive health. Here, we use the Ottawa Charter for health promotion to frame public health and health promotion within prisons and to set out a challenging agenda that would make health a priority for everyone, not just ‘health’ staff, within the prison setting. A series of outcomes under each of the five action areas of the Charter offers a plan of action, showing how each can improve health. We also go further than the Ottawa Charter, to comment on how the values of emancipatory health promotion need to permeate prison health discourse, along with the concept of salutogenesis
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