153 research outputs found
Sedation and weaning from mechanical ventilation: time for âbest practiceâ to catch up with new realities?
Delivery of sedation in anticipation of weaning of adult patients from prolonged mechanical ventilation is an arena of critical care medicine where opinion-based practice is currently hard to avoid because robust evidence is lacking. We offer some views on this subject, hoping to stimulate debate among colleagues
Data capture by digital pen in clinical trials: A qualitative and quantitative study.
International audienceOBJECTIVES: To investigate the use of the digital pen (DP) system to collect data in a clinical trial. To assess the accuracy of the system in this setting. DESIGN: Qualitative study based on semistructured interviews and a focus group. Quantitative study comparing the DP system and a double manual data-entry system in accuracy of acquiring data by variable type (tick boxes, dates, numbers, letters). SETTING: An ongoing randomised multicentric clinical trial in tertiary care in France. PARTICIPANTS: 27 investigators involved in the trial (anaesthetists) who did or did not include patients, 4 study monitors and the study coordinator. RESULTS: Six key findings emerged: 1) the DP system was easy to use; its utilisation was intuitive, even for investigators inexperienced in informatics; 2) despite its portability, the DP was not always used in front of patients; 3) the DP system did not affect patient recruitment; 4) most of the technical problems of the system occurred during setup (compatibility, password access, antivirus software); 5) the main advantage was quickness of data availability for the study coordination staff and the main hindrance was the extra time required for online verification; and 6) all investigators were ready to use the system again. The investigators had to check 16% of data obtained by the DP system during the verification step. There is no relevant difference between the number of errors for the DP and the double manual data-entry systems: 8/5022 versus 6/5022 data entries. 5 out of 8 DP-system failures were due to the intelligent character recognition system. CONCLUSION: The DP system has a good acceptability among all investigators in a clinical setting, whether they are experienced with computers or not, and a good accuracy, as compared with double manual data entry
Dark Matter and Baryons in the Most X-ray Luminous and Merging Galaxy Cluster RX J1347.5-1145
The galaxy cluster RX J1347-1145 is one of the most X-ray luminous and most
massive clusters known. Its extreme mass makes it a prime target for studying
issues addressing cluster formation and cosmology. In this paper we present new
high-resolution HST/ACS and Chandra X-ray data. The high resolution and
sensitivity of ACS enabled us to detect and quantify several new multiply
imaged sources, we now use a total of eight for the strong lensing analysis.
Combining this information with shape measurements of weak lensing sources in
the central regions of the cluster, we derive a high-resolution,
absolutely-calibrated mass map. This map provides the best available
quantification of the total mass of the central part of the cluster to date. We
compare the reconstructed mass with that inferred from the new Chandra X-ray
data, and conclude that both mass estimates agree extremely well in the
observed region, namely within 400 / h_70 kpc of the cluster center. In
addition we study the major baryonic components (gas and stars) and hence
derive the dark matter distribution in the center of the cluster. We find that
the dark matter and baryons are both centered on the BCG within the
uncertainties (alignment is better than <10 kpc). We measure the corresponding
1-D profiles and find that dark matter distribution is consistent with both NFW
and cored profiles, indicating that a more extended radial analysis is needed
to pinpoint the concentration parameter, and hence the inner slope of the dark
matter profile.Comment: 12 pages, Accepted for publication in ApJ, full-res version
http://www.physics.ucsb.edu/~marusa/RXJ1347.pd
High Resolution XMM-Newton Spectroscopy of the Cooling Flow Cluster A3112
We examine high signal to noise XMM-Newton European Photon Imaging Camera
(EPIC) and Reflection Grating Spectrometer (RGS) observations to determine the
physical characteristics of the gas in the cool core and outskirts of the
nearby rich cluster A3112. The XMM-Newton Extended Source Analysis Software
data reduction and background modeling methods were used to analyze the XMM-
Newton EPIC data. From the EPIC data we find that the iron and silicon
abundance gradients show significant increase towards the center of the cluster
while the oxygen abundance profile is centrally peaked but has a shallower
distribution than that of iron. The X-ray mass modeling is based on the
temperature and deprojected density distributions of the intra-cluster medium
determined from EPIC observations. The total mass of A3112 obeys the M-T
scaling relations found using XMM-Newton and Chandra observations of massive
clusters at R500. The gas mass fraction f_gas= 0.149^{+0.036}_{-0.032} at R500,
is consistent with the seven-year WMAP results. The comparisons of line fluxes
and flux limits on the Fe XVII and Fe XVIII lines obtained from high resolution
RGS spectra indicate that there is no spectral evidence for cooler gas
associated with the cluster with temperature below 1.0 keV in the central <38"
(\sim 52 kpc) region of A3112. High resolution RGS spectra also yield an upper
limit to the turbulent motions in compact core of A3112 (206 km/s). We find
that the energy contribution of turbulence to total energy is less than 6 per
cent. This upper limit is consistent with the amount of energy contribution
measured in recent high resolution simulations of relaxed galaxy clusters.Comment: Accepted for publication. 14 pages, 12 Figures and 9 Table
Delphi-Consensus Weights for Ischemic and Bleeding Events to Be Included in a Composite Outcome for RCTs in Thrombosis Prevention
To weight ischemic and bleeding events according to their severity to be used in a composite outcome in RCTs in the field of thrombosis prevention.Using a Delphi consensus method, a panel of anaesthesiology and cardiology experts rated the severity of thrombotic and bleeding clinical events. The ratings were expressed on a 10-point scale. The median and quartiles of the ratings of each item were returned to the experts. Then, the panel members evaluated the events a second time with knowledge of the group responses from the first round. Cronbach's a was used as a measure of homogeneity for the ratings. The final rating for each event corresponded to the median rating obtained at the last Delphi round.Of 70 experts invited, 32 (46%) accepted to participate. Consensus was reached at the second round as indicated by Cronbach's a value (0.99 (95% CI 0.98-1.00)) so the Delphi was stopped. Severity ranged from under-popliteal venous thrombosis (medianâ=â3, Q1â=â2; Q3â=â3) to ischemic stroke or intracerebral hemorrhage with severe disability at 7 days and massive pulmonary embolism (medianâ=â9, Q1â=â9; Q3â=â9). Ratings did not differ according to the medical specialty of experts.These ratings could be used to weight ischemic and bleeding events of various severity comprising a composite outcome in the field of thrombosis prevention
The Atacama Cosmology Telescope: Cosmology from Galaxy Clusters Detected via the Sunyaev-Zel'dovich Effect
We present constraints on cosmological parameters based on a sample of
Sunyaev-Zel'dovich-selected galaxy clusters detected in a millimeter-wave
survey by the Atacama Cosmology Telescope. The cluster sample used in this
analysis consists of 9 optically-confirmed high-mass clusters comprising the
high-significance end of the total cluster sample identified in 455 square
degrees of sky surveyed during 2008 at 148 GHz. We focus on the most massive
systems to reduce the degeneracy between unknown cluster astrophysics and
cosmology derived from SZ surveys. We describe the scaling relation between
cluster mass and SZ signal with a 4-parameter fit. Marginalizing over the
values of the parameters in this fit with conservative priors gives sigma_8 =
0.851 +/- 0.115 and w = -1.14 +/- 0.35 for a spatially-flat wCDM cosmological
model with WMAP 7-year priors on cosmological parameters. This gives a modest
improvement in statistical uncertainty over WMAP 7-year constraints alone.
Fixing the scaling relation between cluster mass and SZ signal to a fiducial
relation obtained from numerical simulations and calibrated by X-ray
observations, we find sigma_8 = 0.821 +/- 0.044 and w = -1.05 +/- 0.20. These
results are consistent with constraints from WMAP 7 plus baryon acoustic
oscillations plus type Ia supernoava which give sigma_8 = 0.802 +/- 0.038 and w
= -0.98 +/- 0.053. A stacking analysis of the clusters in this sample compared
to clusters simulated assuming the fiducial model also shows good agreement.
These results suggest that, given the sample of clusters used here, both the
astrophysics of massive clusters and the cosmological parameters derived from
them are broadly consistent with current models.Comment: 12 pages, 7 figures. Submitted to Ap
Recommended from our members
Dark Matter and Baryons in the Most X-ray Luminous and Merging Galaxy Cluster RX
CorrespondĂȘncias entre Joachim Le Breton e a corte portuguesa na Europa: o nascimento da MissĂŁo ArtĂstica de 1816
A series of documents kept at the National Archive of Tombo Tower in Lisbon offers us important tools to understand the origin of the 1 81 6 Artistic Mission. Although some Brazilian historians have already explored this field extensively - including Afonso d'Escragnolle Taunay, MĂĄrio Barata and MĂĄrio Pedrosa in their invaluable publications, not to mention Jean-Baptiste Debret in his writings - it is important to shed new light on this subject so that we may understand how the project of art and industrial education was conceived in Europe byJoachim Le Breton. How did the Mission's project come about? This paper proposes to review certain letters kept at the Tombo Tower and exchanged between Portuguese diplomats and Le Breton in 1815, while the latter was still in Paris, for the ultimate purpose of retracing the first steps of this story.Uma sĂ©rie de documentos conservados no Arquivo Nacional da Torre do Tombo, em Lisboa, oferece-nos ainda instrumentos significativos para a compreensĂŁo da origem da MissĂŁo ArtĂstica de 1816. Embora alguns historiadores brasileiros tenham jĂĄ explorado intensamente este campo, dentre os quais as preciosas publicaçÔes de Afonso d'Escragnolle Taunay, MĂĄrio Barata e MĂĄrio Pedrosa - destacando-se tambĂ©m os escritos deJean-Baptiste Debret -, convĂ©m buscar novas luzes para entender a concepção do projeto de ensino artĂstico e industrial, ainda na Europa, pelas mĂŁos de Joachim Le Breton. Como surgiu o projeto da MissĂŁo? Este artigo tem como objetivo a anĂĄlise de algumas correspondĂȘncias conservadas na Torre do Tombo, trocadas entre Le Breton e os diplomatas portugueses em 1815, ainda em Paris, visando Ă recuperação dos primeiros passos desta histĂłria
CMB-S4: Forecasting Constraints on Primordial Gravitational Waves
CMB-S4---the next-generation ground-based cosmic microwave background (CMB)
experiment---is set to significantly advance the sensitivity of CMB
measurements and enhance our understanding of the origin and evolution of the
Universe, from the highest energies at the dawn of time through the growth of
structure to the present day. Among the science cases pursued with CMB-S4, the
quest for detecting primordial gravitational waves is a central driver of the
experimental design. This work details the development of a forecasting
framework that includes a power-spectrum-based semi-analytic projection tool,
targeted explicitly towards optimizing constraints on the tensor-to-scalar
ratio, , in the presence of Galactic foregrounds and gravitational lensing
of the CMB. This framework is unique in its direct use of information from the
achieved performance of current Stage 2--3 CMB experiments to robustly forecast
the science reach of upcoming CMB-polarization endeavors. The methodology
allows for rapid iteration over experimental configurations and offers a
flexible way to optimize the design of future experiments given a desired
scientific goal. To form a closed-loop process, we couple this semi-analytic
tool with map-based validation studies, which allow for the injection of
additional complexity and verification of our forecasts with several
independent analysis methods. We document multiple rounds of forecasts for
CMB-S4 using this process and the resulting establishment of the current
reference design of the primordial gravitational-wave component of the Stage-4
experiment, optimized to achieve our science goals of detecting primordial
gravitational waves for at greater than , or, in the
absence of a detection, of reaching an upper limit of at CL.Comment: 24 pages, 8 figures, 9 tables, submitted to ApJ. arXiv admin note:
text overlap with arXiv:1907.0447
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