1,857 research outputs found
Vacuum Stability of the wrong sign Scalar Field Theory
We apply the effective potential method to study the vacuum stability of the
bounded from above (unstable) quantum field potential. The
stability ( and the mass renormalization
( conditions force the effective
potential of this theory to be bounded from below (stable). Since bounded from
below potentials are always associated with localized wave functions, the
algorithm we use replaces the boundary condition applied to the wave functions
in the complex contour method by two stability conditions on the effective
potential obtained. To test the validity of our calculations, we show that our
variational predictions can reproduce exactly the results in the literature for
the -symmetric theory. We then extend the applications
of the algorithm to the unstudied stability problem of the bounded from above
scalar field theory where classical analysis prohibits the
existence of a stable spectrum. Concerning this, we calculated the effective
potential up to first order in the couplings in space-time dimensions. We
find that a Hermitian effective theory is instable while a non-Hermitian but
-symmetric effective theory characterized by a pure imaginary
vacuum condensate is stable (bounded from below) which is against the classical
predictions of the instability of the theory. We assert that the work presented
here represents the first calculations that advocates the stability of the
scalar potential.Comment: 21pages, 12 figures. In this version, we updated the text and added
some figure
Preterm with appendicular abscess and subcapsular liver haematoma: an unreported association
Neonatal appendicitis is a rare yet serious condition. Known reported associations are Hirschsprung’s disease, necrotising enterocolitis (NEC) and cystic fibrosis. The occurrence of subcapsular liver haematoma in preterm neonates can be life threatening. We present an unreported association of these two serious conditions in a preterm infant with appendicular abscess and subcapsular liver haematoma. She presented with sepsis, enlarged liver and tender right iliac fossa mass. Laparotomy was performed for possible complicated NEC. Intraoperatively, there was an appendicular abscess with a small subcapsular liver haematoma and no evidence of NEC. Appendectomy and peritoneal toilet were performed. She had a stormy postoperative period due to sepsis, thrombocytopaenia and expansion of her liver haematoma. The pathology of her appendix was in keeping with appendicitis, with no evidence of NEC. Her liver haematoma gradually resolved. Suction rectal biopsy showed normal ganglia. She was discharged after 7 weeks and remained well since then.Keywords: hematoma, liver, neonatal appendicitis, preterm, subcapsula
Prevalence of HCV Infections Among Hemodialysis Patients in Al Gharbiyah Governorate, Egypt
Introduction: Hepatitis C virus (HCV) is a significant problem for patients undergoing hemodialysis (HD) treatment. This medical problem has never been studied in Al Gharbiyah Governorate; this study was conductedaiming to estimate the prevalence of anti-HCV positive patients and the incidence of seroconversion in its different HD units.Methods: All 2351 patients maintained on HD in the eight towns of Al Gharbiyah Governorate were interviewed and their anti-HCV status was tested by a third-generation enzyme immunoassay. Patients whotested negative for anti-HCV at the start of the study were re-assessed monthly for HCV seroconversion and at the end of the study all patients were screened for HCV antibodies. Results: At the start of our study in March 2011, we found that 824 out of 2351 patients (35%) were anti-HCV reactive. At the end of study in November 2011, we found that HCV seroconversion occurred in 168 out of1527 patients (11%) who were HCV free at the start of the study. By the end of the study, a total of 42.2% were found to be anti-HCV reactive.Conclusion: The study demonstrated high prevalence of anti-HCV in HD units in Al Gharbiyah Governorate. Similar studies must be conducted in all Egyptian governorates’ HD units to evaluate this major health problem all over Egypt. We also encourage strict application of preventive strategies for HCV infection in all health institutes, especially HD units
Soliton stripes in two-dimensional nonlinear photonic lattices
We study experimentally the interaction of a soliton with a nonlinear
lattice. We observe the formation of a novel type of composite soliton created
by strong coupling of mutually incoherent periodic and localized beam
components. By imposing an initial transverse momentum on the soliton stripe,
we observe the effect of lattice compression and deformation.Comment: three pages, four figure
Association between aortic sclerosis and coronary artery disease
Background: Although there is a recognized link between cardiovascular hazards and coronary artery disease (CAD), it is still unknown whether aortic sclerosis and CAD are linked.Objective: This study aimed to check whether if there is a link between aortic sclerosis and the existence and severity of coronary artery disease .Patients and methods: 204 individuals were enrolled in the study, transthoracic echocardiographic, and coronary angiography were done. Aortic leaflets were tested for the amount of thickness in the short axis view. The involvement of coronary arteries represented by the gensini score and the association between aortic valve sclerosis score and the degree and severity of coronary affection was investigated using the Gensini score.Results: The individuals were divided into 2 groups grounded on the severity of aortic valve sclerosis. Group A (GP A) included patients with aortic valve sclerosis (AVS) ≥ 2 and group B (GP B) included patients with AVS < 2. In GP A, the right coronary cusp was the most afflicted one, whereas the LAD was the most affected in coronaries. The degree and severity of CAD were more significant in GP A, as evidenced by a higher Gensini score value of 39.27 versus 28.84 in GP B.Conclusion: AVS has been found to be correlated with the presence and severity of CAD and could be used as a potential surrogate marker for the illness
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