33 research outputs found
Overcoming High Energy Backgrounds at Pulsed Spallation Sources
Instrument backgrounds at neutron scattering facilities directly affect the
quality and the efficiency of the scientific measurements that users perform.
Part of the background at pulsed spallation neutron sources is caused by, and
time-correlated with, the emission of high energy particles when the proton
beam strikes the spallation target. This prompt pulse ultimately produces a
signal, which can be highly problematic for a subset of instruments and
measurements due to the time-correlated properties, and different to that from
reactor sources. Measurements of this background have been made at both SNS
(ORNL, Oak Ridge, TN, USA) and SINQ (PSI, Villigen, Switzerland). The
background levels were generally found to be low compared to natural
background. However, very low intensities of high-energy particles have been
found to be detrimental to instrument performance in some conditions. Given
that instrument performance is typically characterised by S/N, improvements in
backgrounds can both improve instrument performance whilst at the same time
delivering significant cost savings. A systematic holistic approach is
suggested in this contribution to increase the effectiveness of this.
Instrument performance should subsequently benefit.Comment: 12 pages, 8 figures. Proceedings of ICANS XXI (International
Collaboration on Advanced Neutron Sources), Mito, Japan. 201
Irbesartan in patients with heart failure and preserved ejection fraction
Background: Approximately 50% of patients with heart failure have a left ventricular ejection fraction of at least 45%, but no therapies have been shown to improve the outcome of these patients. Therefore, we studied the effects of irbesartan in patients with this syndrome.
Methods: We enrolled 4128 patients who were at least 60 years of age and had New York Heart Association class II, III, or IV heart failure and an ejection fraction of at least 45% and randomly assigned them to receive 300 mg of irbesartan or placebo per day. The primary composite outcome was death from any cause or hospitalization for a cardiovascular cause (heart failure, myocardial infarction, unstable angina, arrhythmia, or stroke). Secondary outcomes included death from heart failure or hospitalization for heart failure, death from any cause and from cardiovascular causes, and quality of life.
Results: During a mean follow-up of 49.5 months, the primary outcome occurred in 742 patients in the irbesartan group and 763 in the placebo group. Primary event rates in the irbesartan and placebo groups were 100.4 and 105.4 per 1000 patient-years, respectively (hazard ratio, 0.95; 95% confidence interval [CI], 0.86 to 1.05; P=0.35). Overall rates of death were 52.6 and 52.3 per 1000 patient-years, respectively (hazard ratio, 1.00; 95% CI, 0.88 to 1.14; P=0.98). Rates of hospitalization for cardiovascular causes that contributed to the primary outcome were 70.6 and 74.3 per 1000 patient-years, respectively (hazard ratio, 0.95; 95% CI, 0.85 to 1.08; P=0.44). There were no significant differences in the other prespecified outcomes.
Conclusions: Irbesartan did not improve the outcomes of patients with heart failure and a preserved left ventricular ejection fraction. (ClinicalTrials.gov number, NCT00095238.)
The SPARC Toroidal Field Model Coil Program
The SPARC Toroidal Field Model Coil (TFMC) Program was a three-year effort
between 2018 and 2021 that developed novel Rare Earth Yttrium Barium Copper
Oxide (REBCO) superconductor technologies and then successfully utilized these
technologies to design, build, and test a first-in-class, high-field (~20 T),
representative-scale (~3 m) superconducting toroidal field coil. With the
principal objective of demonstrating mature, large-scale, REBCO magnets, the
project was executed jointly by the MIT Plasma Science and Fusion Center (PSFC)
and Commonwealth Fusion Systems (CFS). The TFMC achieved its programmatic goal
of experimentally demonstrating a large-scale high-field REBCO magnet,
achieving 20.1 T peak field-on-conductor with 40.5 kA of terminal current, 815
kN/m of Lorentz loading on the REBCO stacks, and almost 1 GPa of mechanical
stress accommodated by the structural case. Fifteen internal demountable
pancake-to-pancake joints operated in the 0.5 to 2.0 nOhm range at 20 K and in
magnetic fields up to 12 T. The DC and AC electromagnetic performance of the
magnet, predicted by new advances in high-fidelity computational models, was
confirmed in two test campaigns while the massively parallel, single-pass,
pressure-vessel style coolant scheme capable of large heat removal was
validated. The REBCO current lead and feeder system was experimentally
qualified up to 50 kA, and the crycooler based cryogenic system provided 600 W
of cooling power at 20 K with mass flow rates up to 70 g/s at a maximum design
pressure of 20 bar-a for the test campaigns. Finally, the feasibility of using
passive, self-protection against a quench in a fusion-scale NI TF coil was
experimentally assessed with an intentional open-circuit quench at 31.5 kA
terminal current.Comment: 17 pages 9 figures, overview paper and the first of a six-part series
of papers covering the TFMC Progra
Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences
The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & NemĂ©sio 2007; Donegan 2008, 2009; NemĂ©sio 2009aâb; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported
by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on
18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based
researchers who signed it in the short time span from 20 September to 6 October 2016