1,023 research outputs found
Plasmas and Controlled Nuclear Fusion
Contains reports on three research projects.U. S. Atomic Energy Commission (Contract AT(30-1)-3980
Plasma Dynamics
Contains research objectives and summary of research.U.S. Atomic Energy Commission (Contract AT(11-1)-3070)National Science Foundation (Grant GK-37979X)National Science Foundation (Grant GK-28282X1
Do Gamma-Ray Bursts Originate from an Extended Galactic Halo of High-Velocity Neutron Stars?
The Îł-ray burst brightness distribution in inhomogeneous and the distribution on the sky is nearly isotropic. These features argue against an association with Îł-ray bursts with those Galactic objects that are known to exhibit a strong concentration toward the Galactic center or plane. The observed statistical properties indicate a cosmological origin. Circumstantial evidence suggests that neutron stars are involved in the burst phenomenon. HEre we consdier Population II neutron stars in an extended Galatic Halo (EGH) as an alternative to cosmological scenaries. The BATSE data indicate a small deviation from isotropy near the 2 Ï level of statistical significance. If confirmed for an increasing number of bursts, these anisotropies could rule out cosmological scenarios. On the other hand, EGH models require small anisotropies like those observed by BATSE. We consdier simple distribution models to determine the generic properties such halos must have to be consistent with the observations and discuss the implications of the corresponding distance scale on burst models
Plasmas and Controlled Nuclear Fusion
Contains reports on five research projects.U. S. Atomic Energy Commission (Contract AT(30-1)-3980
Observation of the Askaryan Effect: Coherent Microwave Cherenkov Emission from Charge Asymmetry in High Energy Particle Cascades
We present the first direct experimental evidence for the charge excess in
high energy particle showers predicted nearly 40 years ago by Askaryan. We
directed bremsstrahlung photons from picosecond pulses of 28.5 GeV electrons at
the SLAC Final Focus Test Beam facility into a 3.5 ton silica sand target,
producing electromagnetic showers several meters long. A series of antennas
spanning 0.3 to 6 GHz were used to detect strong, sub-nanosecond radio
frequency pulses produced whenever a shower was present. The measured electric
field strengths are consistent with a completely coherent radiation process.
The pulses show 100% linear polarization, consistent with the expectations of
Cherenkov radiation. The field strength versus depth closely follows the
expected particle number density profile of the cascade, consistent with
emission from excess charge distributed along the shower. These measurements
therefore provide strong support for experiments designed to detect high energy
cosmic rays and neutrinos via coherent radio emission from their cascades.Comment: 10 pages, 4 figures. Submitted to Phys. Rev. Let
2019 EULAR recommendations for the generic core competences of health professionals in rheumatology
© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ. Background/objectives: To maintain and optimise the quality of care provided by health professionals in rheumatology (HPRs), adequate educational offerings are needed. This task force (TF) aimed to develop evidence-based recommendations for the generic core competences of HPRs, with specific reference to nurses, physical therapists (PTs) and occupational therapists (OTs) to serve as a basis for their postgraduate education. Methods: The EULAR standardised operating procedures for the development of recommendations were followed. A TF including rheumatologists, nurses, PTs, OTs, patient-representatives, an educationalist, methodologists and researchers from 12 countries met twice. In the first TF meeting, 13 research questions were defined to support a systematic literature review (SLR). In the second meeting, the SLR evidence was discussed and recommendations formulated. Subsequently, level of evidence and strength of recommendation were assigned and level of agreement (LoA) determined (0-10 rating scale). Results: Three overarching principles were identified and 10 recommendations were developed for the generic core competences of HPRs. The SLR included 79 full-text papers, 20 of which addressed the competences, knowledge, skills, attitudes and/or educational needs of HPRs from multiple professions. The average LoA for each recommendation ranged from 9.42 to 9.79. Consensus was reached both on a research and educational agenda. Conclusion: Evidence and expert opinion informed a set of recommendations providing guidance on the generic core competences of HPRs. Implementation of these recommendations in the postgraduate education of HPRs at the international and national level is advised, considering variation in healthcare systems and professional roles
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