16 research outputs found
The -3N problem with separable interactions
The -3N-interaction is studied within the four-body Faddeev-Yakubovsky
theory adopting purely separable forms for the two- and three-body
subamplitudes, limiting the basic two-body interactions to s-waves only. The
corresponding separable approximation for the integral kernels is obtained by
using the Hilbert-Schmidt procedure. Results are presented for the -H
scattering amplitude and for the total elastic cross section for energies below
the triton break-up threshold.Comment: revised version accepted for Phys. Rev. C, 16 pages revtex including
6 eps-figures, formal part shortene
Colour transparency: a novel test of QCD in nuclear interactions
Colour transparency is a cute and indispensable property of QCD as the gauge
theory of strong interaction. CT tests of QCD consist of production of the
perturbative small-sized hadronic state and measuring the strngth of its
non-perturbative diffraction nteraction in a nuclear matter. The energy
depenednce of the final- state interaction in a nuclear matter probes a
dynamical evolution from the perturbative small-sized state to the full-sized
nonperturbative hadron. QCD observables of CT experiments correspond to a novel
mechanism of scanning of hadronic wave functions from the large nonperturbative
to the small perturbative size. In these lectures, which are addressed to
experimentalists and theorists, I discuss the principle ideas of CT physics and
the physics potential of the hadron and electron facilities in the > 10 GeV
energy range. The special effort was made to present the material in the
pedagigical and self-consistent way, with an emphasis on the underlying rich
quantum-mechanical interference phenomena.Comment: 82 pages, 28 figures on request from the author., Landau Institute
rep. 9/93. (Lecture notes), [email protected]
Modern Ab Initio Approaches and Applications in Few-Nucleon Physics with A \ge 4
We present an overview of the evolution of ab initio methods for few-nucleon
systems with A \ge 4, tracing the progress made that today allows precision
calculations for these systems. First a succinct description of the diverse
approaches is given. In order to identify analogies and differences the methods
are grouped according to different formulations of the quantum mechanical
many-body problem. Various significant applications from the past and present
are described. We discuss the results with emphasis on the developments
following the original implementations of the approaches. In particular we
highlight benchmark results which represent important milestones towards
setting an ever growing standard for theoretical calculations. This is relevant
for meaningful comparisons with experimental data. Such comparisons may reveal
whether a specific force model is appropriate for the description of nuclear
dynamics.Comment: extension of the previous version from 70 to 78 pages, 24 figures, 17
tables, in press: Progress in Particle and Nuclear Physic
Feasibility and Safety of Evaluating Patients with Prior Coronary Artery Disease Using an Accelerated Diagnostic Algorithm in a Chest Pain Unit.
An accelerated diagnostic protocol for evaluating low-risk patients with acute chest pain in a cardiologist-based chest pain unit (CPU) is widely employed today. However, limited data exist regarding the feasibility of such an algorithm for patients with a history of prior coronary artery disease (CAD). The aim of the current study was to assess the feasibility and safety of evaluating patients with a history of prior CAD using an accelerated diagnostic protocol. We evaluated 1,220 consecutive patients presenting with acute chest pain and hospitalized in our CPU. Patients were stratified according to whether they had a history of prior CAD or not. The primary composite outcome was defined as a composite of readmission due to chest pain, acute coronary syndrome, coronary revascularization, or death during a 60-day follow-up period. Overall, 268 (22%) patients had a history of prior CAD. Non-invasive evaluation was performed in 1,112 (91%) patients. While patients with a history of prior CAD had more comorbidities, the two study groups were similar regarding hospitalization rates (9% vs. 13%, p = 0.08), coronary angiography (13% vs. 11%, p = 0.41), and revascularization (6.5% vs. 5.7%, p = 0.8) performed during CPU evaluation. At 60-days the primary endpoint was observed in 12 (1.6%) and 6 (3.2%) patients without and with a history of prior CAD, respectively (p = 0.836). No mortalities were recorded. To conclude, Patients with a history of prior CAD can be expeditiously and safely evaluated using an accelerated diagnostic protocol in a CPU with outcomes not differing from patients without such a history
Patient evaluation flow chart.
<p>* Patients with a negative evaluation were discharged. <sup>#</sup> Positive evaluation includes: hospitalization during the observation period in the chest pain unit and patients with a positive non-invasive tests who were hospitalized for further investigation. CAD, Coronary artery disease; CPU, Chest pain unit</p
Outcomes of patients during the observation period in the chest pain unit.
<p>Outcomes of patients during the observation period in the chest pain unit.</p
Distribution of imaging tests between the study groups.
<p>MPS, Myocardial perfusion scintigraphy; MDCT, Multidetector computed tomography; Echo, Stress echocardiography; CAD, Coronary artery disease.</p