1,161,740 research outputs found
Low- and intermediate-energy nucleon-nucleon interactions and the analysis of deuteron photodisintegration within the dispersion relation technique
The nucleon-nucleon interaction in the region of the nucleon kinetic energy
up to 1000 MeV is analysed together with the reaction in the
photon energy range MeV. Nine nucleon-nucleon -channel
partial amplitudes are reconstructed in the dispersion relation method:
, , , , , , ,
and . Correspondingly, the dispersive representation of partial
amplitudes , and is given. Basing
on that, we have performed parameter-free calculation of the amplitude , taking into account: pole diagram, nucleon-nucleon
final-state rescattering , and inelastic
final-state rescatterings , and . The
partial amplitudes for nine above-mentioned channels are found. It is shown
that the process is significant for the waves ,
, , at MeV, while for the waves , , dominates at MeV.
Meson exchange current contributions into the deuteron disintegration are
estimated: they are significant at MeV.Comment: 22 pages, LaTeX, epsfig.sty, tabl
Recommended from our members
Teleneurology clinics for polyneuropathy: a pilot study.
INTRODUCTION:Polyneuropathy (PN) is a common condition with significant morbidity. We developed tele-polyneuropathy (tele-PN) clinics to improve access to neurology and increase guideline-concordant PN care. This article describes the mixed-methods evaluation of pilot tele-PN clinics at three community sites within the Greater Los Angeles VA Healthcare System. METHODS:For the first 25 patients (48 scheduled visits), we recorded the duration of the tele-PN visit and exam; the performance on three guideline-concordant care indicators (PN screening labs, opiate reduction, physical therapy for falls); and patient-satisfaction scores. We elicited comments about the tele-PN clinic from patients and the clinical team. We combined descriptive statistics with qualitative themes to determine the feasibility and acceptability of the tele-PN clinics. RESULTS:The average tele-PN encounter and exam times were 28.5 and 9.1 min, respectively. PN screening lab completion increased from 80 to 100%. Opiate freedom improved from 68 to 88%. Physical therapy for patients with recent falls increased from 58 to 100%. The tele-PN clinic was preferred for follow-up over in-person clinics in 86% of cases. Convenience was paramount to the clinic's success, saving an average of 231 min per patient in round-trip travel. The medical team's caring and collaborative spirit received high praise. While the clinic's efficiency was equal or superior to in-person care, the limited treatment options for PN and the small clinical exam space are areas for improvement. CONCLUSION:In this pilot, we were able to efficiently see and examine patients remotely, promote guideline-concordant PN care, and provide a high-satisfaction encounter
Gluonic effects in eta and eta-prime physics
We review the theory and phenomenology of the axial U(1) problem with
emphasis on the role of gluonic degrees of freedom in eta and eta' production
processes, especially the low-energy pN -> pN eta and pN -> pN eta' reactions.Comment: 20 pages, 2 figures, Invited talk at the WASA Workshop on Eta
Physics, October 2001, Uppsala, Swede
Planetary Nebulae: Observational Properties, Mimics, and Diagnostics
The total number of true, likely and possible planetary nebulae (PN) now
known in the Milky Way is nearly 3000, double the number known a decade ago.
The new discoveries are a legacy of the recent availability of wide field,
narrowband imaging surveys, primarily in the light of H-alpha. In this paper,
we summarise the various PN discovery techniques, and give an overview of the
many types of objects which mimic PN and which appear as contaminants in both
Galactic and extragalactic samples. Much improved discrimination of classical
PN from their mimics is now possible based on the wide variety of high-quality
multiwavelength data sets that are now available. We offer improved taxonomic
and observational definitions for the PN phenomenon based on evaluation of
these better diagnostic capabilities. However, we note that evidence is
increasing that the PN phenomenon is heterogeneous, and PN are likely to be
formed from multiple evolutionary scenarios. In particular, the relationships
between some collimated symbiotic outflows and bipolar PN remain uncertain.Comment: 25 pages, 6 figures; presentation at the workshop on the Legacies of
the Macquarie/AAO/Strasbourg H-alpha Planetary Nebula project, accepted by
the Publications of the Astronomical Society of Australia (PASA
Planetary Nebula Surveys: Past, Present and Future
In this review we cover the detection, identification and astrophysical
importance of planetary nebulae (PN). The legacy of the historic Perek &
Kohoutek and Acker et al. catalogues is briefly covered before highlighting the
more recent but significant progress in PN discoveries in our Galaxy and the
Magellanic Clouds. We place particular emphasis on the major MASH and the IPHAS
catalogues, which, over the last decade alone, have essentially doubled
Galactic and LMC PN numbers. We then discuss the increasing role and importance
that multi-wavelength data is playing in both the detection of candidate PN and
the elimination of PN mimics that have seriously biased previous PN
compilations. The prospects for future surveys and current efforts and
prospects for PN detections in external galaxies are briefly discussed due to
their value both as cosmic distance indicators and as kinematical probes of
galaxies and dark matter properties.Comment: 8 pages, 1 figure, Proceedings of the Asymmetric Planetary Nebula V
Conference (Invited Review, Lake District, England, June 2010
Comparing Post-Newtonian and Numerical-Relativity Precession Dynamics
Binary black-hole systems are expected to be important sources of
gravitational waves for upcoming gravitational-wave detectors. If the spins are
not colinear with each other or with the orbital angular momentum, these
systems exhibit complicated precession dynamics that are imprinted on the
gravitational waveform. We develop a new procedure to match the precession
dynamics computed by post-Newtonian (PN) theory to those of numerical binary
black-hole simulations in full general relativity. For numerical relativity NR)
simulations lasting approximately two precession cycles, we find that the PN
and NR predictions for the directions of the orbital angular momentum and the
spins agree to better than with NR during the inspiral,
increasing to near merger. Nutation of the orbital plane on the
orbital time-scale agrees well between NR and PN, whereas nutation of the spin
direction shows qualitatively different behavior in PN and NR. We also examine
how the PN equations for precession and orbital-phase evolution converge with
PN order, and we quantify the impact of various choices for handling partially
known PN terms
- …