102 research outputs found
Patient-reported conformity of informed consent procedures and participation in clinical research
Background: There is growing evidence that the quality of informed consent in clinical research is often sub-optimal. Aims: To explore the conformity of patient recruitment with recommended informed consent procedures among patients who were invited to participate in a clinical study at a general teaching hospital, and to examine the association between consent procedures and the patients' decision to participate. Design and Methods: All inpatients discharged during a 1-month period were invited to complete a mailed survey in which they reported whether they were invited to participate in a study and whether 13 recommended elements of informed consent actually occurred. Results: Among 1303 respondents, 265 (20.3%) reported that they had been invited to participate in a study, and 191 (72.1%) accepted. While the majority of potential participants were fully informed about practical issues related to the study (e.g. what their participation would consist in), <50% were informed of possible risks or benefits, and only 20% about the origin of the study funds. Only 60% reported satisfactory answers to items assessing the overall information process (e.g. explanations were easy to understand). Older and sicker patients reported lower levels of conformity with informed consent procedures, as did patients who refused to participate in a study. Conclusions: Our results confirm that informed consent procedures fail to meet standards for many patients. In particular, consent information should be adapted to the needs of older and sicker patients. Improving the quality of informed consent may increase patients' participation in clinical researc
Temperature-induced crossovers in the static roughness of a one-dimensional interface
At finite temperature and in presence of disorder, a one-dimensional elastic
interface displays different scaling regimes at small and large lengthscales.
Using a replica approach and a Gaussian Variational Method (GVM), we explore
the consequences of a finite interface width on the small-lengthscale
fluctuations. We compute analytically the static roughness of the
interface as a function of the distance between two points on the
interface. We focus on the case of short-range elasticity and random-bond
disorder. We show that for a finite width two temperature regimes exist.
At low temperature, the expected thermal and random-manifold regimes,
respectively for small and large scales, connect via an intermediate `modified'
Larkin regime, that we determine. This regime ends at a temperature-independent
characteristic `Larkin' length. Above a certain `critical' temperature that we
identify, this intermediate regime disappears. The thermal and random-manifold
regimes connect at a single crossover lengthscale, that we compute. This is
also the expected behavior for zero width. Using a directed polymer
description, we also study via a second GVM procedure and generic scaling
arguments, a modified toy model that provides further insights on this
crossover. We discuss the relevance of the two GVM procedures for the roughness
at large lengthscale in those regimes. In particular we analyze the scaling of
the temperature-dependent prefactor in the roughness B(r)\sim T^{2
\text{\thorn}} r^{2 \zeta} and its corresponding exponent \text{\thorn}. We
briefly discuss the consequences of those results for the quasistatic creep law
of a driven interface, in connection with previous experimental and numerical
studies
Finite-temperature and finite-time scaling of the directed polymer free-energy with respect to its geometrical fluctuations
We study the fluctuations of the directed polymer in 1+1 dimensions in a
Gaussian random environment with a finite correlation length {\xi} and at
finite temperature. We address the correspondence between the geometrical
transverse fluctuations of the directed polymer, described by its roughness,
and the fluctuations of its free-energy, characterized by its two-point
correlator. Analytical arguments are provided in favor of a generic scaling law
between those quantities, at finite time, non-vanishing {\xi} and explicit
temperature dependence. Numerical results are in good agreement both for
simulations on the discrete directed polymer and on a continuous directed
polymer (with short-range correlated disorder). Applications to recent
experiments on liquid crystals are discussed
Multiscaling analysis of ferroelectric domain wall roughness
Using multiscaling analysis, we compare the characteristic roughening of
ferroelectric domain walls in PZT thin films with numerical simulations of
weakly pinned one-dimensional interfaces. Although at length scales up to a
length scale greater or equal to 5 microns the ferroelectric domain walls
behave similarly to the numerical interfaces, showing a simple mono-affine
scaling (with a well-defined roughness exponent), we demonstrate more complex
scaling at higher length scales, making the walls globally multi-affine
(varying roughness exponent at different observation length scales). The
dominant contributions to this multi-affine scaling appear to be very localized
variations in the disorder potential, possibly related to dislocation defects
present in the substrate.Comment: 5 pages, 4 figure
Beam Test of a Segmented Foil SEM Grid
A prototype Secondary-electron Emission Monitor (SEM) was installed in the 8
GeV proton transport line for the MiniBooNE experiment at Fermilab. The SEM is
a segmented grid made with 5 um Ti foils, intended for use in the 120 GeV NuMI
beam at Fermilab. Similar to previous workers, we found that the full
collection of the secondary electron signal requires a bias voltage to draw the
ejected electrons cleanly off the foils, and this effect is more pronounced at
larger beam intensity. The beam centroid and width resolutions of the SEM were
measured at beam widths of 3, 7, and 8 mm, and compared to calculations.
Extrapolating the data from this beam test, we expect a centroid and width
resolutions of 20um and 25 um, respectively, in the NuMI beam which has 1 mm
spot size.Comment: submitted to Nucl. Instr. Meth.
Meta-analysis of antibiotics versus appendicectomy for non-perforated acute appendicitis
Background: For more than a century, appendicectomy has been the treatment of choice for appendicitis. Recent trials have challenged this view. This study assessed the benefits and harms of antibiotic therapy compared with appendicectomy in patients with non-perforated appendicitis. Methods: A comprehensive search was conducted for randomized trials comparing antibiotic therapy with appendicectomy in patients with non-perforated appendicitis. Key outcomes were analysed using random-effects meta-analysis, and the quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results: Five studies including 1116 patients reported major complications in 25 (4.9 per cent) of 510 patients in the antibiotic and 41 (8.4 per cent) of 489 in the appendicectomy group: risk difference -2.6 (95 per cent c.i. -6.3 to 1.1) per cent (low-quality evidence). Minor complications occurred in 11 (2.2 per cent) of 510 and 61 (12.5 per cent) of 489 patients respectively: risk difference -7.2 (-18.1 to 3.8) per cent (very low-quality evidence). Of 550 patients in the antibiotic group, 47 underwent appendicectomy within 1 month: pooled estimate 8.2 (95 per cent c.i. 5.2 to 11.8) per cent (high-quality evidence). Within 1 year, appendicitis recurred in 114 of 510 patients in the antibiotic group: pooled estimate 22.6 (15.6 to 30.4) per cent (high-quality evidence). For every 100 patients with non-perforated appendicitis, initial antibiotic therapy compared with prompt appendicectomy may result in 92 fewer patients receiving surgery within the first month, and 23 more experiencing recurrent appendicitis within the first year. Conclusion: The choice of medical versus surgical management in patients with clearly uncomplicated appendicitis is value-and preference-dependent, suggesting a change in practice towards shared decision-making is necessary.Peer reviewe
Disordered Elastic Systems and One-Dimensional Interfaces
We briefly introduce the generic framework of Disordered Elastic Systems
(DES), giving a short `recipe' of a DES modeling and presenting the quantities
of interest in order to probe the static and dynamical disorder-induced
properties of such systems. We then focus on a particular low-dimensional DES,
namely the one-dimensional interface in short-ranged elasticity and
short-ranged quenched disorder. Illustrating different elements given in the
introductory sections, we discuss specifically the consequences of the
interplay between a finite temperature T>0 and a finite interface width \xi>0
on the static geometrical fluctuations at different lengthscales, and the
implications on the quasistatic dynamics.Comment: Proceedings of the International Workshop on Electronic Crystals
(ECRYS), Cargese (2011
Low intensity pulsed ultrasound (LIPUS) for bone healing: A clinical practice guideline
Does low intensity pulsed ultrasound (LIPUS) accelerate recovery in adults and children who have experienced bone fractures or osteotomy (cutting of a bone)? An expert panel rapidly produced these recommendations based on a linked systematic review triggered by a large multi-centre randomised trial in adults with tibial fracture
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