35 research outputs found
Four layer bandage compared with short stretch bandage for venous leg ulcers: systematic review and meta-analysis of randomised controlled trials with data from individual patients
<p><b>Objective:</b> To compare the effectiveness of two types of compression treatment (four layer bandage and short stretch bandage) in people with venous leg ulceration.</p>
<p><b>Design:</b> Systematic review and meta-analysis of patient level data.</p>
<p><b>Data:</b> sources Electronic databases (the Cochrane Central Register of Controlled Trials, the Cochrane Wounds Group Specialised Register, Medline, Embase, CINAHL, and National Research Register) and reference lists of retrieved articles searched to identify relevant trials and primary investigators. Primary investigators of eligible trials were invited to contribute raw data for re-analysis.</p>
<p><b>Review:</b> methods Randomised controlled trials of four layer bandage compared with short stretch bandage in people with venous leg ulceration were eligible for inclusion. The primary outcome for the meta-analysis was time to healing. Cox proportional hazards models were run to compare the methods in terms of time to healing with adjustment for independent predictors of healing. Secondary outcomes included incidence and number of adverse events per patient.</p>
<p><b>Results:</b> Seven eligible trials were identified (887 patients), and patient level data were retrieved for five (797 patients, 90% of known randomised patients). The four layer bandage was associated with significantly shorter time to healing: hazard ratio (95% confidence interval) from multifactorial model based on five trials was 1.31 (1.09 to 1.58), P=0.005. Larger ulcer area at baseline, more chronic ulceration, and previous ulceration were all independent predictors of delayed healing. Data from two trials showed no evidence of a difference in adverse event profiles between the two bandage types.</p>
<p><b>Conclusions:</b> Venous leg ulcers in patients treated with four layer bandages heal faster, on average, than those of people treated with the short stretch bandage. Benefits were consistent across patients with differing prognostic profiles.</p>
Directly imaging damped Ly α galaxies at z > 2 – III. The star formation rates of neutral gas reservoirs at z ∼ 2.7
We present results from a survey designed to probe the star formation properties of 32 damped Lyman α systems (DLAs) at z ∼ 2.7. By using the ‘double-DLA’ technique that eliminates the glare of the bright background quasars, we directly measure the rest-frame far-ultraviolet flux from DLAs and their neighbouring galaxies. At the position of the absorbing gas, we place stringent constraints on the unobscured star formation rates (SFRs) of DLAs to 2σ limits of ψ˙<0.09-0.27M⊙ yr−1, corresponding to SFR surface densities Σsfr < 10−2.6–10−1.5M⊙ yr−1 kpc−2. The implications of these limits for the star formation law, metal enrichment, and cooling rates of DLAs are examined. By studying the distribution of impact parameters as a function of SFRs for all the galaxies detected around these DLAs, we place new direct constraints on the bright end of the UV luminosity function of DLA hosts. We find that ≤13 per cent of the hosts have ψ˙≥2M⊙ yr−1 at impact parameters bdla≤(ψ˙/M⊙yr−1)0.8+6kpc, differently from current samples of confirmed DLA galaxies. Our observations also disfavour a scenario in which the majority of DLAs arise from bright Lyman-break galaxies at distances 20 ≤ bdla < 100 kpc. These new findings corroborate a picture in which DLAs do not originate from highly star-forming systems that are coincident with the absorbers, and instead suggest that DLAs are associated with faint, possibly isolated, star-forming galaxies. Potential shortcomings of this scenario and future strategies for further investigation are discussed
Reconstructing the primordial power spectrum from the CMB
We propose a straightforward and model independent methodology for
characterizing the sensitivity of CMB and other experiments to wiggles,
irregularities, and features in the primordial power spectrum. Assuming that
the primordial cosmological perturbations are adiabatic, we present a function
space generalization of the usual Fisher matrix formalism, applied to a CMB
experiment resembling Planck with and without ancillary data. This work is
closely related to other work on recovering the inflationary potential and
exploring specific models of non-minimal, or perhaps baroque, primordial power
spectra. The approach adopted here, however, most directly expresses what the
data is really telling us. We explore in detail the structure of the available
information and quantify exactly what features can be reconstructed and at what
statistical significance.Comment: 43 pages Revtex, 23 figure
Constraints on neutrino masses from WMAP5 and BBN in the lepton asymmetric universe
In this paper, we put constraints on neutrino properties such as mass
and degeneracy parameters from WMAP5 data and light element
abundances by using a Markov chain Monte Carlo (MCMC) approach. In order to
take consistently into account the effects of the degeneracy parameters, we run
the Big Bang Nucleosynthesis code for each value of and the other
cosmological parameters to estimate the Helium abundance, which is then used to
calculate CMB anisotropy spectra instead of treating it as a free parameter. We
find that the constraint on is fairly robust and does not vary very
much even if the lepton asymmetry is allowed, and is given by ().Comment: 19 pages, 7 figures, 5 table
The neutral hydrogen cosmological mass density at z = 5
We present the largest homogeneous survey of z > 4.4 damped Lyα systems (DLAs) using the spectra of 163 QSOs that comprise the Giant Gemini GMOS (GGG) survey. With this survey we make the most precise high-redshift measurement of the cosmological mass density of neutral hydrogen, ΩHi. At such high redshift, important systematic uncertainties in the identification of DLAs are produced by strong intergalactic medium absorption and QSO continuum placement. These can cause spurious DLA detections, result in real DLAs being missed or bias the inferred DLA column density distribution. We correct for these effects using a combination of mock and higher resolution spectra, and show that for the GGG DLA sample the uncertainties introduced are smaller than the statistical errors on ΩHi. We find ΩHI=0.98+0.20−0.18×10−3 at 〈z〉 = 4.9, assuming a 20 per cent contribution from lower column density systems below the DLA threshold. By comparing to literature measurements at lower redshifts, we show that ΩHi can be described by the functional form ΩHI(z)∝(1+z)0.4. This gradual decrease from z = 5 to 0 is consistent with the bulk of H I gas being a transitory phase fuelling star formation, which is continually replenished by more highly ionized gas from the intergalactic medium and from recycled galactic winds
Nucleosynthesis Constraints on a Massive Gravitino in Neutralino Dark Matter Scenarios
The decays of massive gravitinos into neutralino dark matter particles and
Standard Model secondaries during or after Big-Bang nucleosynthesis (BBN) may
alter the primordial light-element abundances. We present here details of a new
suite of codes for evaluating such effects, including a new treatment based on
PYTHIA of the evolution of showers induced by hadronic decays of massive,
unstable particles such as a gravitino. We also develop an analytical treatment
of non-thermal hadron propagation in the early universe, and use this to derive
analytical estimates for light-element production and in turn on decaying
particle lifetimes and abundances. We then consider specifically the case of an
unstable massive gravitino within the constrained minimal supersymmetric
extension of the Standard Model (CMSSM). We present upper limits on its
possible primordial abundance before decay for different possible gravitino
masses, with CMSSM parameters along strips where the lightest neutralino
provides all the astrophysical cold dark matter density. We do not find any
CMSSM solution to the cosmological Li7 problem for small m_{3/2}. Discounting
this, for m_{1/2} ~ 500 GeV and tan beta = 10 the other light-element
abundances impose an upper limit m_{3/2} n_{3/2}/n_\gamma < 3 \times 10^{-12}
GeV to < 2 \times 10^{-13} GeV for m_{3/2} = 250 GeV to 1 TeV, which is similar
in both the coannihilation and focus-point strips and somewhat weaker for tan
beta = 50, particularly for larger m_{1/2}. The constraints also weaken in
general for larger m_{3/2}, and for m_{3/2} > 3 TeV we find a narrow range of
m_{3/2} n_{3/2}/n_\gamma, at values which increase with m_{3/2}, where the Li7
abundance is marginally compatible with the other light-element abundances.Comment: 74 pages, 40 Figure
On the kinematics of cold, metal-enriched galactic fountain flows in nearby star-forming falaxies
Galaxie
The bimodal absorption system imaging campaign (BASIC). I. A dual population of low-metallicity absorbers at z < 1
Instrumentatio
Development of an international standard set of patient-centred outcome measures for overall paediatric health: a consensus process
Objective: To develop an Overall Pediatric Health Standard Set (OPH-SS) of outcome measures that captures what matters to young people and their families and recognising the biopsychosocial aspects of health for all children and adolescents regardless of health condition. Design: A modified Delphi process. Setting: The International Consortium for Health Outcomes Measurement convened an international Working Group (WG) comprised of 23 international experts from 12 countries in the field of paediatrics, family medicine, psychometrics as well as patient advisors. The WG participated in 11 video-conferences, through a modified Delphi process and 9 surveys between March 2018 and January 2020 consensus was reached on a final recommended health outcome standard set. By a literature review conducted in March 2018, 1136 articles were screened for clinician and patient-reported or proxy-reported outcomes. Further, 4315 clinical trials and 12 paediatric health surveys were scanned. Between November 2019 and January 2020, the final standard set was endorsed by a patient validation (n=270
The physical properties of z > 2 Lyman limit systems: new constraints for feedback and accretion models
e study the physical properties of a homogeneous sample of 157 optically thick absorption line systems at redshifts ∼1.8–4.4, selected from a high-dispersion spectroscopic survey of Lyman limit systems (LLSs). By means of multiple ionization models and Bayesian techniques, we derive the posterior probability distribution functions for the density, metallicity, temperature and dust content of the absorbing gas. We find that z > 2 LLSs are highly ionized with ionization parameters between −3 ≲ log U ≲ −2, depending on the H I column density. LLSs are characterized by low temperatures (T 2 are characterized by a broad unimodal distribution over > 4 orders of magnitude, with a peak at log Z/Z⊙ ∼ −2. LLSs are metal poor, significantly less enriched than DLAs, with ∼70 per cent of the metallicity PDF below log Z/Z⊙ ≤ −1.5. The median metallicity of super LLSs with logNHI≥19 rapidly evolves with redshift, with a 10-fold increase between z ∼ 2.1–3.6 (∼1.5 Gyr). Based on this sample, we find that LLSs at z = 2.5–3.5 account for ∼15 per cent of all the metals produced by UV-selected galaxies. The implications for theories of cold gas accretion and metal ejection from galaxies are also discussed