140 research outputs found
The Impact of Business Ownership Change on Employee Relations: Buy-outs in the UK and the Netherlands
A buy-out is a fundamental change in the structure of ownership that may affect the way employee relations develop within an organisation. Little is known about the impact of buyouts upon employee relations. This paper aims to address this gap. We focus on two main questions. First, what are the effects of a buy-out on employee relations in an organisation? Second, does the national institutional context affect the impact of buy-outs on employee relations? The paper reports changes to employee relations in buy-outs in the contrasting institutional environments of the UK and the Netherlands. Overall, we find that buy-outs positively affect HR practices with increases in training, employee involvement, the number of employees and pay levels. The positive effects appear to be significantly stronger in a less institutionalised environment like the UK than the more institutionalised environment of the Netherlands. Buy-outs raised HRM practices in the UK to a level closer although still below that of Dutch buy-outs
Constraining the dark energy dynamics with the cosmic microwave background bispectrum
We consider the influence of the dark energy dynamics at the onset of cosmic
acceleration on the Cosmic Microwave Background (CMB) bispectrum, through the
weak lensing effect induced by structure formation. We study the line of sight
behavior of the contribution to the bispectrum signal at a given angular
multipole : we show that it is non-zero in a narrow interval centered at a
redshift satisfying the relation , where the
wavenumber corresponds to the scale entering the non-linear phase, and is
the cosmological comoving distance. The relevant redshift interval is in the
range 0.1\lsim z\lsim 2 for multipoles 1000\gsim\ell\gsim 100; the signal
amplitude, reflecting the perturbation dynamics, is a function of the
cosmological expansion rate at those epochs, probing the dark energy equation
of state redshift dependence independently on its present value. We provide a
worked example by considering tracking inverse power law and SUGRA Quintessence
scenarios, having sensibly different redshift dynamics and respecting all the
present observational constraints. For scenarios having the same present
equation of state, we find that the effect described above induces a projection
feature which makes the bispectra shifted by several tens of multipoles, about
10 times more than the corresponding effect on the ordinary CMB angular power
spectrum.Comment: 15 pages, 7 figures, matching version accepted by Physical Review D,
one figure improve
The role of the humoral immune response to Clostridium difficile toxins A and B in susceptibility to C. difficile infection: a case-control study
Antibody levels to Clostridium difficile toxin A (TcdA), but not toxin B (TcdB), have been found to determine risk of C. difficile infection (CDI). Historically, TcdA was thought to be the key virulence factor; however the importance of TcdB in disease is now established. We re-evaluated the role of antibodies to TcdA and TcdB in determining patient susceptibility to CDI in two separate patient cohorts. In contrast to earlier studies, we find that CDI patients have lower pre-existing IgA titres to TcdB, but not TcdA, when compared to control patients. Our findings suggest that mucosal immunity to TcdB may be important in the early stages of infection and identifies a possible target for preventing CDI progression
Repeated antibiotic exposure and risk of hospitalisation and death following COVID-19 infection (OpenSAFELY): a matched case–control study
Background
Identifying potential risk factors related to severe COVID-19 outcomes is important. Repeated intermittent antibiotic use is known be associated with adverse outcomes. This study aims to examine whether prior frequent antibiotic exposure is associated with severe COVID-19 outcomes.
Methods
With the approval of NHS England, we used the OpenSAFELY platform, which integrated primary and secondary care, COVID-19 test, and death registration data. This matched case–control study included 0.67 million patients (aged 18–110 years) from an eligible 2.47 million patients with incident COVID-19 by matching with replacement. Inclusion criteria included registration within one general practice for at least 3 years and infection with incident COVID-19. Cases were identified according to different severity of COVID-19 outcomes. Cases and eligible controls were 1:6 matched on age, sex, region of GP practice, and index year and month of COVID-19 infection. Five quintile groups, based on the number of previous 3-year antibiotic prescriptions, were created to indicate the frequency of prior antibiotic exposure. Conditional logistic regression used to compare the differences between case and control groups, adjusting for ethnicity, body mass index, comorbidities, vaccination history, deprivation, and care home status. Sensitivity analyses were done to explore potential confounding and the effects of missing data.
Findings
Based on our inclusion criteria, between February 1, 2020 and December 31, 2021, 98,420 patients were admitted to hospitals and 22,660 died. 55 unique antibiotics were prescribed. A dose–response relationship between number of antibiotic prescriptions and risk of severe COVID-19 outcome was observed. Patients in the highest quintile with history of prior antibiotic exposure had 1.80 times greater odds of hospitalisation compared to patients without antibiotic exposure (adjusted odds ratio [OR] 1.80, 95% Confidence Interval [CI] 1.75–1.84). Similarly, the adjusted OR for hospitalised patients with death outcomes was 1.34 (95% CI 1.28–1.41). Larger number of prior antibiotic type was also associated with more severe COVID-19 related hospital admission. The adjusted OR of quintile 5 exposure (the most frequent) with more than 3 antibiotic types was around 2 times larger than quintile 1 (only 1 type; OR 1.80, 95% CI 1.75–1.84 vs. OR 1.03, 95% CI 1.01–1.05).
Interpretation
Our observational study has provided evidence that antibiotic exposure frequency and diversity may be associated with COVID-19 severity, potentially suggesting adverse effects of repeated intermittent antibiotic use. Future work could work to elucidate causal links and potential mechanisms. Antibiotic stewardship should put more emphasis on long-term antibiotic exposure and its adverse outcome to increase the awareness of appropriate antibiotics use.
Funding
Health Data Research UK and National Institute for Health Research
Weak lensing, dark matter and dark energy
Weak gravitational lensing is rapidly becoming one of the principal probes of
dark matter and dark energy in the universe. In this brief review we outline
how weak lensing helps determine the structure of dark matter halos, measure
the expansion rate of the universe, and distinguish between modified gravity
and dark energy explanations for the acceleration of the universe. We also
discuss requirements on the control of systematic errors so that the
systematics do not appreciably degrade the power of weak lensing as a
cosmological probe.Comment: Invited review article for the GRG special issue on gravitational
lensing (P. Jetzer, Y. Mellier and V. Perlick Eds.). V3: subsection on
three-point function and some references added. Matches the published versio
Near-IR Atlas of S0-Sa galaxies (NIRS0S)
An atlas of Ks-band images of 206 early-type galaxies is presented, including
160 S0-S0/a galaxies, 12 ellipticals, and 33 Sa galaxies. A majority of the
Atlas galaxies belong to a magnitude-limited (mB<12.5 mag) sample of 185 NIRS0S
(Near-IR S0 galaxy Survey) galaxies. To assure that mis-classified S0s are not
omitted, 25 ellipticals from RC3 classified as S0s in the Carnegie Atlas were
included in the sample. The images are 2-3 mag deeper than 2MASS images. Both
visual and photometric classifications are made. Special attention is paid to
the classification of lenses, coded in a systematic manner. A new lens-type,
called a 'barlens', is introduced. Also, boxy/peanut/x-shaped structures are
identified in many barred galaxies, even-though the galaxies are not seen in
edge-on view, indicating that vertical thickening is not enough to explain
them. Multiple lenses appear in 25% of the Atlas galaxies, which is a challenge
to the hierarchical evolutionary picture of galaxies. Such models need to
explain how the lenses were formed and survived in multiple merger events that
galaxies may have suffered during their lifetimes. Following the early
suggestion by van den Bergh, candidates of S0c galaxies are shown, which
galaxies are expected to be former Sc-type spirals stripped out of gas.Comment: 67 pages (include 16 figures and 6 tables). Accepted to MNRAS 2011
June 1
Observation of hard scattering in photoproduction events with a large rapidity gap at HERA
Events with a large rapidity gap and total transverse energy greater than 5
GeV have been observed in quasi-real photoproduction at HERA with the ZEUS
detector. The distribution of these events as a function of the
centre of mass energy is consistent with diffractive scattering. For total
transverse energies above 12 GeV, the hadronic final states show predominantly
a two-jet structure with each jet having a transverse energy greater than 4
GeV. For the two-jet events, little energy flow is found outside the jets. This
observation is consistent with the hard scattering of a quasi-real photon with
a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil
Three-Dimensional Mapping of the Dark Matter
We study the prospects for three-dimensional mapping of the dark matter to
high redshift through the shearing of faint galaxies images at multiple
distances by gravitational lensing. Such maps could provide invaluable
information on the nature of the dark energy and dark matter. While in
principle well-posed, mapping by direct inversion introduces exceedingly large,
but usefully correlated noise into the reconstruction. By carefully propagating
the noise covariance, we show that lensing contains substantial information,
both direct and statistical, on the large-scale radial evolution of the density
field. This information can be efficiently distilled into low-order
signal-to-noise eigenmodes which may be used to compress the data by over an
order of magnitude. Such compression will be useful for the statistical
analysis of future large data sets. The reconstructed map also contains useful
information on the localization of individual massive dark matter halos, and
hence the dark energy from halo number counts, but its extraction depends
strongly on prior assumptions. We outline a procedure for maximum entropy and
point-source regularization of the maps that can identify alternate
reconstructions.Comment: 11 pages, 5 figures, submitted to PR
Weak Lensing and CMB: Parameter forecasts including a running spectral index
We use statistical inference theory to explore the constraints from future
galaxy weak lensing (cosmic shear) surveys combined with the current CMB
constraints on cosmological parameters, focusing particularly on the running of
the spectral index of the primordial scalar power spectrum, . Recent
papers have drawn attention to the possibility of measuring by
combining the CMB with galaxy clustering and/or the Lyman- forest. Weak
lensing combined with the CMB provides an alternative probe of the primordial
power spectrum. We run a series of simulations with variable runnings and
compare them to semi-analytic non-linear mappings to test their validity for
our calculations. We find that a ``Reference'' cosmic shear survey with
and galaxies per steradian can reduce the
uncertainty on and by roughly a factor of 2 relative to the
CMB alone. We investigate the effect of shear calibration biases on lensing by
including the calibration factor as a parameter, and show that for our
Reference Survey, the precision of cosmological parameter determination is only
slightly degraded even if the amplitude calibration is uncertain by as much as
5%. We conclude that in the near future weak lensing surveys can supplement the
CMB observations to constrain the primordial power spectrum.Comment: 12 pages, 10 figures, revtex4. Final form to appear in Phys Rev
Questioning ten common assumptions about peatlands
Peatlands have been widely studied in terms of their ecohydrology, carbon dynamics, ecosystem services and palaeoenvironmental archives. However, several assumptions are frequently made about peatlands in the academic literature, practitioner reports and the popular media which are either ambiguous or in some cases incorrect. Here we discuss the following ten common assumptions about peatlands:
1. the northern peatland carbon store will shrink under a warming climate;
2. peatlands are fragile ecosystems;
3. wet peatlands have greater rates of net carbon accumulation;
4. different rules apply to tropical peatlands;
5. peat is a single soil type;
6. peatlands behave like sponges;
7. Sphagnum is the main ‘ecosystem engineer’ in peatlands;
8. a single core provides a representative palaeo-archive from a peatland;
9. water-table reconstructions from peatlands provide direct records of past climate change; and
10. restoration of peatlands results in the re-establishment of their carbon sink function.
In each case we consider the evidence supporting the assumption and, where appropriate, identify its shortcomings or ways in which it may be misleading
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