227 research outputs found
Evaluation of the discrete vortex wake cross flow model using vector computers. Part 2: User's manual for DIVORCE
The users manual for the Discrete Vortex Cross flow Evaluator (DIVORCE) computer program is presented. DIVORCE was developed in FORTRAN 4 for the DCD 6600 and CDC 7600 machines. Optimal calls to a NASA vector subroutine package are provided for use with the CDC 7600
PEN: a low energy test of lepton universality
Allowed charged meson decays are characterized by simple dynamics, few
available decay channels, mainly into leptons, and extremely well controlled
radiative and loop corrections. In that sense, pion decays represent a
veritable triumph of the standard model (SM) of elementary particles and
interactions. This relative theoretical simplicity makes charged pion decays a
sensitive means for testing the underlying symmetries and the universality of
weak fermion couplings, as well as for studying pion structure and chiral
dynamics. Even after considerable recent improvements, experimental precision
is lagging far behind that of the theoretical description for pion decays. We
review the current state of experimental study of the pion electronic decay
, or , where the
indicates inclusion and explicit treatment of radiative decay events. We
briefly review the limits on non-SM processes arising from the present level of
experimental precision in decays. Focusing on the PEN
experiment at the Paul Scherrer Institute (PSI), Switzerland, we examine the
prospects for further improvement in the near term.Comment: 11 pages, 5 figures; paper presented at the XIII International
Conference on Heavy Quarks and Leptons, 22-27 May 2016, Blacksburg, Virginia,
US
Global population and conservation status of the Great Black-backed Gull Larus marinus
The Great Black-backed Gull Larus marinus is a generalist species that inhabits temperate and arctic coasts of the north Atlantic Ocean. In recent years, there has been growing concern about population declines at local and regional scales; however, there has been no attempt to robustly assess Great Black-backed Gull population trends across its global range. We obtained the most recent population counts across the species’ range and analysed population trends at a global, continental, and national scale over the most recent three-generation period (1985–2021) following IUCN Red List criteria. We found that, globally, the species has declined by 43%–48% over this period (1.2–1.3% per annum, respectively), from an estimated 291,000 breeding pairs to 152,000–165,000 breeding pairs under two different scenarios. North American populations declined more steeply than European ones (68% and 28%, respectively). We recommend that Great Black-backed Gull should be uplisted from ‘Least Concern’ to ‘Vulnerable’ on the IUCN Red List of Threatened Species under criterion A2 (an estimated reduction in population size >30% over three generations). Larus gulls; gull populations; population assessment; population ecology; bird conservationpublishedVersio
A qualitative study of the learning processes in young physicians treating suicidal patients: from insecurity to personal pattern knowledge and self-confidence
<p>Abstract</p> <p>Background</p> <p>Little empirical work has been done in studying learning processes among newly educated physicians in the mental health field.</p> <p>The aim of the study was to shed light on the meaning of newly educated physicians' lived experiences of learning processes related to treating suicidal patients.</p> <p>Methods</p> <p>Thirteen newly educated physicians narrated their learning experiences while treating suicidal patients in their own practice. The interview texts were transcribed and interpreted using a phenomenological-hermeneutical method inspired by Ricoeur's philosophy.</p> <p>Results</p> <p>There was one main theme, four themes and eleven sub themes. The main theme was: Being in a transitional learning process. The themes and sub themes were: Preparing for practice (Getting tools and training skills, Becoming aware of one's own attitudes); Gaining experience from treating patients (Treating and following up patients over time, Storing memories and recognizing similarities and differences in patients); Participating in the professional community (Being an apprentice, Relating clinical stories and receiving feedback, Sharing emotions from clinical experiences, Receiving support from peers); and Developing personal competence (Having unarticulated awareness, Having emotional knowledge, Achieving self-confidence). The informants gave a detailed account of the learning process; from recognising similarities and differences in patients they have treated, to accumulating pattern knowledge, which then contributed to their personal feelings of competence and confidence. They described their personal competence with cognitive and emotional elements consisting of both articulated and less articulated knowledge. The findings are interpreted in relation to different learning theories that focus on both individual factors and the interaction with the learning environment.</p> <p>Conclusion</p> <p>This study provides additional information about learning experiences of young physicians during the critical transition phase from medical school to early professional life. Peers are used for both learning and support and might represent a more powerful resource in the learning process than previously recognized. Emotional experiences do not seem to be adequately focused upon in supervision, which obviously has relevance both for learning and for the well-being of young professionals. The study indicates some areas of the educational system that could profitably be expanded including stimulating more systematically to critical reflection on and in practice, attention to feelings in the reflective process and provision of more performance feedback to young physicians.</p
Spin decoherence and off-resonance behavior of radiofrequency-driven spin rotations in storage rings
Radiofrequency-driven resonant spin rotators are routinely used as standard
instruments in polarization experiments in particle and nuclear physics.
Maintaining the continuous exact parametric spin-resonance condition of the
equality of the spin rotator and the spin precession frequency during operation
constitutes one of the challenges. We present a detailed analytic description
of the impact of detuning the exact spin resonance on the vertical and the
in-plane precessing components of the polarization. An important part of the
formalism presented here is the consideration of experimentally relevant
spin-decoherence effects. We discuss applications of the developed formalism to
the interpretation of the experimental data on the novel pilot bunch approach
to control the spin-resonance condition during the operation of the
radiofrequency-driven Wien filter that is used as a spin rotator in the first
direct deuteron electric dipole moment measurement at COSY. We emphasize the
potential importance of the hitherto unexplored phase of the envelope of the
horizontal polarization as an indicator of the stability of the
radiofrequency-driven spin rotations in storage rings. The work presented here
serves as a satellite publication to the work published concurrently on the
proof of principle experiment about the so-called pilot bunch approach that was
developed to provide co-magnetometry for the deuteron electric dipole moment
experiment at COSY.Comment: 31 pages, 10 figures, 5 table
Pilot bunch and co-magnetometry of polarized particles stored in a ring
In polarization experiments at storage rings, one of the challenges is to
maintain the spin-resonance condition of a radio-frequency spin rotator with
the spin-precessions of the orbiting particles. Time-dependent variations of
the magnetic fields of ring elements lead to unwanted variations of the spin
precession frequency. We report here on a solution to this problem by shielding
(or masking) one of the bunches stored in the ring from the high-frequency
fields of the spin rotator, so that the masked pilot bunch acts as a
co-magnetometer for the other signal bunch, tracking fluctuations in the ring
on a time scale of about one second. While the new method was developed
primarily for searches of electric dipole moments of charged particles, it may
have far-reaching implications for future spin physics facilities, such as the
EIC and NICA.Comment: 5 pages, 3 figures + references + supplemental material (6 pages, 2
figures, 6 tables + references
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