We measure the large-scale real-space power spectrum P(k) by using a sample of 205,443 galaxies from the Sloan Digital Sky Survey, covering 2417 effective square degrees with mean redshift z similar ...to 0.1. We employ a matrix- based method using pseudo-Karhunen-Loeve eigenmodes, producing uncorrelated minimum-variance measurements in 22 k-bands of both the clustering power and its anisotropy due to redshift-space distortions, with narrow and well-behaved window functions in the range 0.02 h Mpc super(-1) < k < 0.3 h Mpc super(- 1). We pay particular attention to modeling, quantifying, and correcting for potential systematic errors, nonlinear redshift distortions, and the artificial red-tilt caused by luminosity-dependent bias. Our results are robust to omitting angular and radial density fluctuations and are consistent between different parts of the sky. Our final result is a measurement of the real-space matter power spectrum P(k) up to an unknown overall multiplicative bias factor. Our calculations suggest that this bias factor is independent of scale to better than a few percent for k < 0.1 h Mpc super(-1), thereby making our results useful for precision measurements of cosmological parameters in conjunction with data from other experiments such as the Wilkinson Microwave Anisotropy Probe satellite. The power spectrum is not well-characterized by a single power law but unambiguously shows curvature. As a simple characterization of the data, our measurements are well fitted by a flat scale-invariant adiabatic cosmological model with h Omega sub(m) = 0.213 plus or minus 0.023 and capital sigma sub(8) = 0.89 plus or minus 0.02 for L sub(*) galaxies, when fixing the baryon fraction Omega sub(b)/Omega sub(m) = 0.17 and the Hubble parameter h = 0.72; cosmological interpretation is given in a companion paper.
Astrophys.J.657:645-663,2007 We present a Fourier analysis of the clustering of galaxies in the combined
Main galaxy and Luminous Red Galaxy (LRG) Sloan Digital Sky Survey (SDSS) Data
Release 5 (DR5) ...sample. The aim of our analysis is to consider how well we can
measure the cosmological matter density using the signature of the horizon at
matter-radiation equality embedded in the large-scale power spectrum. The new
data constrains the power spectrum on scales 100--600h^-1Mpc with significantly
higher precision than previous analyses of just the SDSS Main galaxies, due to
our larger sample and the inclusion of the LRGs. This improvement means that we
can now reveal a discrepancy between the shape of the measured power and linear
CDM models on scales 0.01<k<0.15hMpc^-1, with linear model fits favouring a
lower matter density (Omega_m=0.22+/-0.04) on scales 0.01<k<0.06hMpc^-1 and a
higher matter density (Omega_m=0.32+/-0.01) when smaller scales are included,
assuming a flat LCDM model with h=0.73 and n_s=0.96. This discrepancy could be
explained by scale-dependent bias and, by analysing subsamples of galaxies, we
find that the ratio of small-scale to large-scale power increases with galaxy
luminosity, so all of the SDSS galaxies cannot trace the same power spectrum
shape over 0.01<k<0.2hMpc^-1. However, the data are insufficient to clearly
show a luminosity-dependent change in the largest scale at which a significant
increase in clustering is observed, although they do not rule out such an
effect. Significant scale-dependent galaxy bias on large-scales, which changes
with the r-band luminosity of the galaxies, could potentially explain
differences in our Omega_m estimates and differences previously observed
between 2dFGRS and SDSS power spectra and the resulting parameter constraints.
Vasopressors are administered to critical care patients to avoid hypotension, which is associated with myocardial injury, kidney injury and death. However, they work by causing vasoconstriction, ...which may reduce blood flow and cause other adverse effects. A mean arterial pressure target typically guides administration. An individual patient data meta-analysis (Lamontagne F, Day AG, Meade MO, Cook DJ, Guyatt GH, Hylands M,
Pooled analysis of higher versus lower blood pressure targets for vasopressor therapy septic and vasodilatory shock.
2018;
:12-21) suggested that greater exposure, through higher mean arterial pressure targets, may increase risk of death in older patients.
To estimate the clinical effectiveness and cost-effectiveness of reduced vasopressor exposure through permissive hypotension (i.e. a lower mean arterial pressure target of 60-65 mmHg) in older critically ill patients.
A pragmatic, randomised clinical trial with integrated economic evaluation.
Sixty-five NHS adult general critical care units.
Critically ill patients aged ≥ 65 years receiving vasopressors for vasodilatory hypotension.
Intervention - permissive hypotension (i.e. a mean arterial pressure target of 60-65 mmHg). Control (usual care) - a mean arterial pressure target at the treating clinician's discretion.
The primary clinical outcome was 90-day all-cause mortality. The primary cost-effectiveness outcome was 90-day incremental net monetary benefit. Secondary outcomes included receipt and duration of advanced respiratory and renal support, mortality at critical care and acute hospital discharge, and questionnaire assessment of cognitive decline and health-related quality of life at 90 days and 1 year.
Of 2600 patients randomised, 2463 (permissive hypotension,
= 1221; usual care,
= 1242) were analysed for the primary clinical outcome. Permissive hypotension resulted in lower exposure to vasopressors than usual care mean duration 46.0 vs. 55.9 hours, difference -9.9 hours (95% confidence interval -14.3 to -5.5 hours); total noradrenaline-equivalent dose 31.5 mg vs. 44.3 mg, difference -12.8 mg (95% CI -18.0 mg to -17.6 mg). By 90 days, 500 (41.0%) patients in the permissive hypotension group and 544 (43.8%) patients in the usual-care group had died (absolute risk difference -2.85%, 95% confidence interval -6.75% to 1.05%;
= 0.154). Adjustment for prespecified baseline variables resulted in an odds ratio for 90-day mortality of 0.82 (95% confidence interval 0.68 to 0.98) favouring permissive hypotension. There were no significant differences in prespecified secondary outcomes or subgroups; however, patients with chronic hypertension showed a mortality difference favourable to permissive hypotension. At 90 days, permissive hypotension showed similar costs to usual care. However, with higher incremental life-years and quality-adjusted life-years in the permissive hypotension group, the incremental net monetary benefit was positive, but with high statistical uncertainty (£378, 95% confidence interval -£1347 to £2103).
The intervention was unblinded, with risk of bias minimised through central allocation concealment and a primary outcome not subject to observer bias. The control group event rate was higher than anticipated.
In critically ill patients aged ≥ 65 years receiving vasopressors for vasodilatory hypotension, permissive hypotension did not significantly reduce 90-day mortality compared with usual care. The absolute treatment effect on 90-day mortality, based on 95% confidence intervals, was between a 6.8-percentage reduction and a 1.1-percentage increase in mortality.
Future work should (1) update the individual patient data meta-analysis, (2) explore approaches for evaluating heterogeneity of treatment effect and (3) explore 65 trial conduct, including use of deferred consent, to inform future trials.
Current Controlled Trials ISRCTN10580502.
This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in
; Vol. 25, No. 14. See the NIHR Journals Library website for further project information.
We measure the cosmological matter density by observing the positions of baryon acoustic oscillations in the clustering of galaxies in the Sloan Digital Sky Survey (SDSS). We jointly analyse the main ...galaxies and LRGs in the SDSS DR5 sample, using over half a million galaxies in total. The oscillations are detected with 99.74% confidence (3.0sigma assuming Gaussianity) compared to a smooth power spectrum. When combined with the observed scale of the peaks within the CMB, we find a best-fit value of Omega_m=0.256+0.029-0.024 (68% confidence interval), for a flat Lambda cosmology when marginalising over the Hubble parameter and the baryon density. This value of the matter density is derived from the locations of the baryon oscillations in the galaxy power spectrum and in the CMB, and does not include any information from the overall shape of the power spectra. This is an extremely clean cosmological measurement as the physics of the baryon acoustic oscillation production is well understood, and the positions of the oscillations are expected to be independent of systematics such as galaxy bias.
Astrophys.J.607:655-660,2004 We present estimates of cosmological parameters from the application of the
Karhunen-Loeve transform to the analysis of the 3D power spectrum of density
fluctuations ...using Sloan Digital Sky Survey galaxy redshifts. We use Omega_m*h
and f_b = Omega_b/Omega_m to describe the shape of the power spectrum, sigma8
for the (linearly extrapolated) normalization, and beta to parametrize linear
theory redshift space distortions. On scales k < 0.16 h/Mpc, our maximum
likelihood values are Omega_m*h = 0.264 +/-0.043, f_b = 0.286 +/- 0.065, sigma8
= 0.966 +/- 0.048, and beta = 0.45 +/- 0.12. When we take a prior on Omega_b
from WMAP, we find Omega_m*h = 0.207 +/- 0.030, which is in excellent agreement
with WMAP and 2dF. This indicates that we have reasonably measured the gross
shape of the power spectrum but we have difficulty breaking the degeneracy
between Omega_m*h and f_b because the baryon oscillations are not resolved in
the current spectroscopic survey window function.
Objective
Fear of negative evaluation is a common concern among individuals with visible differences but has received limited attention in systemic sclerosis (SSc), which can involve substantial ...changes to appearance. The Brief Fear of Negative Evaluation Scale (BFNE) was specifically designed to evaluate fear of negative evaluation. There are currently 3 versions of the BFNE with strong demonstrated measurement properties: two 8‐item versions (BFNE‐S, BFNE‐8) and one 12‐item version (BFNE‐II). The present study evaluated these versions in SSc, and identified the most appropriate version for use among SSc patients.
Methods
Participants were 1,010 patients with SSc enrolled in the Scleroderma Patient‐Centered Intervention Network cohort. Multiple group confirmatory factor analysis, Cronbach's alpha, and Pearson's product‐moment correlations were used to evaluate structural validity, internal consistency reliability, and convergent and divergent validity, respectively.
Results
Confirmatory factor analysis demonstrated that 1‐factor models fit acceptably well for the 12‐item BFNE‐II, the 8‐item BFNE‐S, and the 8‐item BFNE‐8. Additionally, all Cronbach's alphas demonstrated excellent internal consistency reliability (BFNE‐II = 0.98, BFNE‐S = 0.97, BFNE‐8 = 0.96), and all versions had comparable associations with measures of social anxiety, body‐related attitudes, depression, age, and education.
Conclusion
Psychometric support was found for all 3 versions of the BFNE, although the longer 12‐item BFNE‐II did not improve measurement compared to the shorter 8‐item versions (BFNE‐S and BFNE‐8). Of these 2, the BFNE‐S has been more widely studied, with strong validity data in a greater number of populations. Therefore, the BFNE‐S is recommended to assess fear of negative evaluation among patients with SSc.
We present a Fourier analysis of the clustering of galaxies in the combined Main galaxy and Luminous Red Galaxy (LRG) Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) sample. The aim of our ...analysis is to consider how well we can measure the cosmological matter density using the signature of the horizon at matter-radiation equality embedded in the large-scale power spectrum. The new data constrains the power spectrum on scales 100--600h^-1Mpc with significantly higher precision than previous analyses of just the SDSS Main galaxies, due to our larger sample and the inclusion of the LRGs. This improvement means that we can now reveal a discrepancy between the shape of the measured power and linear CDM models on scales 0.01<k<0.15hMpc^-1, with linear model fits favouring a lower matter density (Omega_m=0.22+/-0.04) on scales 0.01<k<0.06hMpc^-1 and a higher matter density (Omega_m=0.32+/-0.01) when smaller scales are included, assuming a flat LCDM model with h=0.73 and n_s=0.96. This discrepancy could be explained by scale-dependent bias and, by analysing subsamples of galaxies, we find that the ratio of small-scale to large-scale power increases with galaxy luminosity, so all of the SDSS galaxies cannot trace the same power spectrum shape over 0.01<k<0.2hMpc^-1. However, the data are insufficient to clearly show a luminosity-dependent change in the largest scale at which a significant increase in clustering is observed, although they do not rule out such an effect. Significant scale-dependent galaxy bias on large-scales, which changes with the r-band luminosity of the galaxies, could potentially explain differences in our Omega_m estimates and differences previously observed between 2dFGRS and SDSS power spectra and the resulting parameter constraints.
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