252 research outputs found
A narrow quasi-bound state
The energies and widths of quasi-bound states with isospin I=1/2 are
evaluated in two methods, the fixed center approximation to the Faddeev
equation and the variational method approach to the effective one-channel
Hamiltonian. The interactions are constructed so that they dynamically
generate the (I=0, ) resonance state. We find
that the system is bound by about 250 MeV from the threshold, MeV. Its width including both the mesonic decay and the
absorption, is estimated to be about 20-40 MeV. The I=0 pair in the
system is found to form a cluster that is similar to the .Comment: 17 pages, 18 figures, 3 table
Electromagnetic mean squared radii of Lambda(1405) in chiral dynamics
The electromagnetic mean squared radii, _E and _M, of Lambda(1405)
are calculated in the chiral unitary model. We describe the excited baryons as
dynamically generated resonances in the octet meson and octet baryon
scattering. We evaluate values of _E and _M for the Lambda(1405) on
the resonance pole and obtain their complex values. We also consider
Lambda(1405) obtained by neglecting decay channels. For the latter case, we
obtain negative and larger absolute electric mean squared radius than that of
typical ground state baryons. This implies that Lambda(1405) has structure that
K^- is widely spread around p.Comment: 7 pages, 4 figures, use elsart3p.cl
Signature of strange dibaryon in kaon-induced reaction
We examine how the signature of the strange-dibaryon resonances in the
barKNN-piSigmaN system shows up in the scattering amplitude on the physical
real energy axis within the framework of Alt-Grassberger-Sandhas (AGS)
equations. The so-called point method is applied to handle the three-body
unitarity cut in the amplitudes. We also discuss the possibility that the
strange-dibaryon production reactions can be used for discriminating between
existing models of the two-body barKN-piSigma system with Lambda(1405).Comment: 4 pages, 6 figures, talk given at The Fifth Asia-Pacific Conference
on Few-Body Problems in Physics 2011 (APFB2011), held in Seoul, Korea, August
22-26, 201
The nature of Lambda(1405) hyperon resonance in chiral dynamics
The nature of the Lambda(1405) is discussed based on the unitarised
coupled-channels approach with chiral dynamics (chiral unitary model). This
approach describes the Kbar N scattering cross sections and the Lambda(1405)
spectra phenomenologically very well. With this successful description of
Lambda(1405), it is found that the Lambda(1405) is composed by two resonance
states having different coupling nature to the meson-baryon states. As a
consequence, the resonance position in the pi Sigma invariant mass spectrum
depends on the initial channel of the Lambda(1405) production. To observe the
Lambda(1405) initiated by the Kbar N channel, K^- d to Lambda(1405) n is one of
the most favorable reactions. Hadronic molecule states with kaons are also
discussed by emphasizing an important role of Lambda(1405) as a quasibound
state of Kbar N.Comment: 8 pages, three figures. Talk given at 10th International Conference
on Hypernuclear and Strange Particle Physics (HYP-X), Tokai, Ibaraki, Japan,
14-18 Sep 2009
Tako-tsubo cardiomyopathy after administration of ergometrine following elective caesarean delivery: a case report
<p>Abstract</p> <p>Introduction</p> <p>Tako-tsubo cardiomyopathy (stress-induced cardiomyopathy or transient left ventricular ballooning) is characterized by clinical suspicion of an acute myocardial infarction with transient apical or midventricular dyskinesia of the left ventricle without significant coronary stenosis on angiography. The etiology of this disease remains obscure. One of the possible causes is myocardial ischemia induced by coronary vasospasm due to sympathetic activation. It has been hypothesized that the application of ergometrine could induce tako-tsubo cardiomyopathy.</p> <p>Case presentation</p> <p>We report the case of a 28-year-old Turkish woman who developed tako-tsubo cardiomyopathy after administration of ergometrine for release of placenta and prevention of bleeding during the post-partum phase in the course of an elective caesarean delivery. Tako-tsubo cardiomyopathy was diagnosed by echocardiography and urgent cardiac magnetic resonance imaging. A coronary angiography was not performed because of the absence of myocardial necrosis or ischemia and signs of myocarditis on cardiac magnetic resonance imaging.</p> <p>Conclusion</p> <p>This life-threatening disease should be excluded in the differential diagnosis by comparing the symptoms with those of typical heart failure, particularly after use of ergometrine.</p
International Expert Consensus Document on Takotsubo Syndrome (Part I): Clinical Characteristics, Diagnostic Criteria, and Pathophysiology
Takotsubo syndrome (TTS) is a poorly recognized heart disease that was initially regarded as a benign condition. Recently, it has been shown that TTS may be associated with severe clinical complications including death and that its prevalence is probably underestimated. Since current guidelines on TTS are lacking, it appears timely and important to provide an expert consensus statement on TTS. The clinical expert consensus document part I summarizes the current state of knowledge on clinical presentation and characteristics of TTS and agrees on controversies surrounding TTS such as nomenclature, different TTS types, role of coronary artery disease, and etiology. This consensus also proposes new diagnostic criteria based on current knowledge to improve diagnostic accuracy
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