162 research outputs found
Atenolol versus losartan in children and young adults with Marfan's syndrome
BACKGROUND : Aortic-root dissection is the leading cause of death in Marfan's syndrome. Studies suggest that with regard to slowing aortic-root enlargement, losartan may be more effective than beta-blockers, the current standard therapy in most centers.
METHODS : We conducted a randomized trial comparing losartan with atenolol in children and young adults with Marfan's syndrome. The primary outcome was the rate of aortic-root enlargement, expressed as the change in the maximum aortic-root-diameter z score indexed to body-surface area (hereafter, aortic-root z score) over a 3-year period. Secondary outcomes included the rate of change in the absolute diameter of the aortic root; the rate of change in aortic regurgitation; the time to aortic dissection, aortic-root surgery, or death; somatic growth; and the incidence of adverse events.
RESULTS : From January 2007 through February 2011, a total of 21 clinical centers enrolled 608 participants, 6 months to 25 years of age (mean [+/- SD] age, 11.5 +/- 6.5 years in the atenolol group and 11.0 +/- 6.2 years in the losartan group), who had an aorticroot z score greater than 3.0. The baseline-adjusted rate of change (+/- SE) in the aortic-root z score did not differ significantly between the atenolol group and the losartan group (-0.139 +/- 0.013 and -0.107 +/- 0.013 standard-deviation units per year, respectively; P = 0.08). Both slopes were significantly less than zero, indicating a decrease in the degree of aortic-root dilatation relative to body-surface area with either treatment. The 3-year rates of aortic-root surgery, aortic dissection, death, and a composite of these events did not differ significantly between the two treatment groups.
CONCLUSIONS : Among children and young adults with Marfan's syndrome who were randomly assigned to losartan or atenolol, we found no significant difference in the rate of aorticroot dilatation between the two treatment groups over a 3-year period
Twenty important research questions in microbial exposure and social equity
Social and political policy, human activities, and environmental change affect the ways in which microbial communities assemble and interact with people. These factors determine how different social groups are exposed to beneficial and/or harmful microorganisms, meaning microbial exposure has an important socioecological justice context. Therefore, greater consideration of microbial exposure and social equity in research, planning, and policy is imperative. Here, we identify 20 research questions considered fundamentally important to promoting equitable exposure to beneficial microorganisms, along with safeguarding resilient societies and ecosystems. The 20 research questions we identified span seven broad themes, including the following: (i) sociocultural interactions; (ii) Indigenous community health and well-being; (iii) humans, urban ecosystems, and environmental processes; (iv) human psychology and mental health; (v) microbiomes and infectious diseases; (vi) human health and food security; and (vii) microbiome-related planning, policy, and outreach. Our goal was to summarize this growing field and to stimulate impactful research avenues while providing focus for funders and policymakers
Measurement of the 72Ge(n,γ) cross section over a wide neutron energy range at the CERN n_TOF facility
The Ge72(n,γ) cross section was measured for neutron energies up to 300keV at the neutron time-of-flight facility n_TOF (CERN), Geneva, for the first time covering energies relevant to heavy-element synthesis in stars. The measurement was performed at the high-resolution beamline EAR-1, using an isotopically enriched GeO272 sample. The prompt capture γ rays were detected with four liquid scintillation detectors, optimized for low neutron sensitivity. We determined resonance capture kernels up to a neutron energy of 43keV, and averaged cross sections from 43 to 300keV. Maxwellian-averaged cross section values were calculated from kT=5 to 100keV, with uncertainties between 3.2% and 7.1%. The new results significantly reduce uncertainties of abundances produced in the slow neutron capture process in massive stars
Neutron capture measurement at the n TOF facility of the 204Tl and 205Tl s-process branching points
Neutron capture cross sections are one of the fundamental nuclear data in
the study of the s (slow) process of nucleosynthesis. More interestingly, the competition
between the capture and the decay rates in some unstable nuclei determines the local
isotopic abundance pattern. Since decay rates are often sensible to temperature and
electron density, the study of the nuclear properties of these nuclei can provide valuable
constraints to the physical magnitudes of the nucleosynthesis stellar environment. Here
we report on the capture cross section measurement of two thallium isotopes, 204Tl
and 205Tl performed by the time-of-flight technique at the n TOF facility at CERN.
At some particular stellar s-process environments, the decay of both nuclei is strongly
enhanced, and determines decisively the abundance of two s-only isotopes of lead,
204Pb and 205Pb. The latter, as a long-lived radioactive nucleus, has potential use
as a chronometer of the last s-process events that contributed to final solar isotopic
abundances
Radiative Neutron Capture Cross-Section Measurement of Ge Isotopes at n_TOF CERN Facility and Its Importance for Stellar Nucleosynthesis
This work was supported by the Austrian Science Fund FWF (J3503), the Adolf Messer Foundation (Germany), the UK Science and Facilities Council (ST/M006085/1), and the European Research Council ERC-2015-StG No. 677497. We also acknowledge the support of the National Science Centre, Poland, under the grant UMO-2016/22/M/ST2/00183, the MSMT of the Czech Republic and the Croatian Science Foundation under the project IP-2018-01-8570.This manuscript summarizes the results of radiative neutron capture cross-section measurements on two stable germanium isotopes, Ge-70 and Ge-73. Experiments were performed at the n_TOF facility at CERN via the time-of-flight technique, over a wide neutron energy range, for all stable germanium isotopes (70,72,73,74, and 76). Results for Ge-70 [Phys. Rev. C 100, 045804 (2019)] and Ge-73 [Phys. Lett. B 790, 458 (2019)] are already published. In the field of nuclear structure, such measurements allow to study excited levels close to the neutron binding energy and to obtain information on nuclear properties. In stellar nucleosynthesis research, neutron induced reactions on germanium are of importance for nucleosynthesis in the weak component of the slow neutron capture processes.Austrian Science Fund (FWF)
J3503Adolf Messer Foundation (Germany)UK Science and Facilities Council
ST/M006085/1European Research Council (ERC)European Commission
677497National Science Centre, Poland
UMO-2016/22/M/ST2/00183Ministry of Education, Youth & Sports - Czech RepublicCroatian Science Foundation
IP-2018-01-857
Search for Gravitational Waves from Intermediate Mass Binary Black Holes
We present the results of a weakly modeled burst search for gravitational
waves from mergers of non-spinning intermediate mass black holes (IMBH) in the
total mass range 100--450 solar masses and with the component mass ratios
between 1:1 and 4:1. The search was conducted on data collected by the LIGO and
Virgo detectors between November of 2005 and October of 2007. No plausible
signals were observed by the search which constrains the astrophysical rates of
the IMBH mergers as a function of the component masses. In the most efficiently
detected bin centered on 88+88 solar masses, for non-spinning sources, the rate
density upper limit is 0.13 per Mpc^3 per Myr at the 90% confidence level.Comment: 13 pages, 4 figures: data for plots and archived public version at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=62326, see also the
public announcement at http://www.ligo.org/science/Publication-S5IMBH
80Se(n,γ) cross-section measurement at CERN n TOF
Radiative neutron capture cross section measurements are of fundamental importance for the study of the slow neutron capture (s-) process of nucleosynthesis. This mechanism is responsible for the formation of most elements heavier than iron in the Universe. Particularly relevant are branching nuclei along the s-process path, which are sensitive to the physical conditions of the stellar environment. One such example is the branching at 79Se (3.27 × 105 y), which shows a thermally dependent ß-decay rate. However, an astrophysically consistent interpretation requires also the knowledge of the closest neighbour isotopes involved. In particular, the 80Se(n,?) cross section directly affects the stellar yield of the "cold"branch leading to the formation of the s-only 82Kr. Experimentally, there exists only one previous measurement on 80Se using the time of flight (TOF) technique. However, the latter suffers from some limitations that are described in this presentation. These drawbacks have been significantly improved in a recent measurement at CERN n TOF. This contribution presents a summary of the latter measurement and the status of the data analysis
Measurement of ⁷³Ge(n,γ) cross sections and implications for stellar nucleosynthesis
73Ge(n,γ) cross sections were measured at the neutron time-of-flight facility n_TOF at CERN up to neutron energies of 300 keV, providing for the first time experimental data above 8 keV. Results indicate that the stellar cross section at kT=30 keV is 1.5 to 1.7 times higher than most theoretical predictions. The new cross sections result in a substantial decrease of 73Ge produced in stars, which would explain the low isotopic abundance of 73Ge in the solar system
Charged-particle nuclear modification factors in PbPb and pPb collisions at √=sNN=5.02 TeV
The spectra of charged particles produced within the pseudorapidity window
|η| < 1 at √
sNN = 5.02 TeV are measured using 404 µb
−1 of PbPb and 27.4 pb−1 of pp data
collected by the CMS detector at the LHC in 2015. The spectra are presented over the
transverse momentum ranges spanning 0.5 < pT < 400 GeV in pp and 0.7 < pT < 400 GeV
in PbPb collisions. The corresponding nuclear modification factor, RAA, is measured in
bins of collision centrality. The RAA in the 5% most central collisions shows a maximal
suppression by a factor of 7–8 in the pT region of 6–9 GeV. This dip is followed by an increase,
which continues up to the highest pT measured, and approaches unity in the vicinity
of pT = 200 GeV. The RAA is compared to theoretical predictions and earlier experimental
results at lower collision energies. The newly measured pp spectrum is combined with the
pPb spectrum previously published by the CMS collaboration to construct the pPb nuclear
modification factor, RpA, up to 120 GeV. For pT > 20 GeV, RpA exhibits weak momentum
dependence and shows a moderate enhancement above unity
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