2,708 research outputs found
Prospects of Detecting Massive Charged Higgs from Hadronic Decay H -> tb in CMS
The possibility to detect the massive charged Higgs boson H using the
hadronic decay channel H -> tb in the associated production pp -> tH + X in the
CMS experiment at LHC is studied. There is a large background from ttbb events
which makes the observation difficult. Detection of a Higgs signal in this
channel requires an excellent b-tagging performance. Good calorimeter mass
resolution is also necessary for the full event reconstruction.Comment: 13 pages, 18 figure
Numerical Investigations of Oscillons in 2 Dimensions
Oscillons, extremely long-living localized oscillations of a scalar field,
are studied in theories with quartic and sine-Gordon potentials in two spatial
dimensions. We present qualitative results concentrating largely on a study in
frequency space via Fourier analysis of oscillations. Oscillations take place
at a fundamental frequency just below the threshold for the production of
radiation, with exponentially suppressed harmonics. The time evolution of the
oscillation frequency points indirectly to a life time of at least 10 million
oscillations. We study also elliptical perturbations of the oscillon, which are
shown to decay. We finish by presenting results for boosted and collided
oscillons, which point to a surprising persistence and soliton-like behaviour.Comment: Matches the published version (12 pages, 34 figures
Kinematic Constraints on Formation of Bound States of Cosmic Strings - Field Theoretical Approach
Superstring theory predicts the potential formation of string networks with
bound states ending in junctions. Kinematic constraints for junction formation
have been derived within the Nambu-Goto thin string approximation. Here we test
these constraints numerically in the framework of the Abelian-Higgs model in
the Type-I regime and report on good agreement with the analytical predictions.
We also demonstrate that strings can effectively pass through each other when
they meet at speeds slightly above the critical velocity permitting bound state
formation. This is due to reconnection effects that are beyond the scope of the
Nambu-Goto approximation.Comment: 6 pages, 12 eps figures - matches the published versio
Effects of external stream flow and afterbody variations on the performance of a plug nozzle
The off-design operation of an isentropic plug nozzle designed for a jet pressure ratio of 15 was investigated experimentally at subsonic Mach numbers up to 0.9 and jet pressure ratios up to 5. When installed in a cylindrical nacelle with a sharp turn at the nozzle lip, the interaction of the jet and the external stream produced low pressures on the base formed by the high lip angle. These low pressures increased the nacelle drag and caused an overexpansion of the jet, which resulted in lower pressures on the plug and, hence, reduced thrust. With a boattail ahead of the plug nozzle, the base pressures were increased and the jet overexpansion significantly reduced
Effect of External Boundary Layer on Performance of Axisymmetric Inlet at Mach Numbers of 3.0 and 2.5
The effect of an external boundary layer on the performance of an axisymmetric external-internal-compression inlet was evaluated at Mach numbers of 3.0 and 2.5 and Reynolds numbers from 2.2 to 0.5 x 10(exp 6) per foot. The inlet was tested at locations up to two-thirds of the way into the 1.7- and 9.0-inch boundary layers generated by a flat plate and the tunnel floor, respectively. The inlet could be readily started at all conditions tested, including those where the boundary layer was separated upstream of the inlet by the various shock systems during the restart cycle. Although the inlet performance decreased with increasing immersion into the boundary layer at both Mach numbers, the inlet was more sensitive to boundary-layer ingestion at the design Mach number of 3.0
SPh functionalized bridging-vinyliminium diiron and diruthenium complexes
The SPh functionalized vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(SPh)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] [R = Xyl, R′ = Me, 2a; R = Me, R′ = Me, 2b; R = 4-C6H4OMe, R′ = Me, 2c; R = Xyl, R′ = CH2OH, 2d; R = Me, R′ = CH2OH, 2e; Xyl = 2,6-Me2C6H3] are generated in high yields by treatment of the corresponding vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(H)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (1a–e) with NaH in the presence of PhSSPh. Likewise, the diruthenium complex [Ru2{μ-η1:η3-Cγ(Me)Cβ(SPh)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (2f) was obtained from the corresponding vinyliminium complex [Ru2{μ-η1:η3-Cγ(Me)Cβ(H)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (1f). The synthesis of 2c is accompanied by the formation, in comparable amounts, of the aminocarbyne complex [Fe2{μ-CN(Me)(4-C6H4OMe)}(SPh)(μ-CO)(CO)(Cp)2] (3). The molecular structures of 2d, 2e and 3 have been determined by X-ray diffraction studies
Post-Infarction Ventricular Septal Defect: A quarter century experience
Objectives: Post-infarction ventricular septal defect (VSD) is one of the known complications after acute myocardial infarction. This study investigated the clinical results after surgical repair of VSD. Methods: This retrospective study included all patients undergoing surgical repair of VSD from 1996 to 2020 in Oman. Results: Out of a total of 75 patients, 62.5% were men, with a mean age of 59 years. The mean follow-up was 17.2 (7.5) years. Of the 75 patients, 34 (45.3%) patients died within 30 days. Total survival was 41.3% at 5 years, while the 10-year survival rate was 33.3%. Outcomes and predictors for 30 days mortality were the number of concomitant coronary involvement and anastomoses performed, residual postoperative shunt and postoperative dialysis. Conclusion: Even with surgical repair, early mortality of post-infarction septal defect is still considerably high. Early repair and the anatomically posterior rupture are predictors of early mortality. In patients surviving the immediate postoperative period, long-term survival is limited by pre-existing coronary artery disease, postoperative renal failure and the presence of a residual postoperative shunt.
Keywords: Post Infarction Heart Rupture; Ventricular Septal Rupture; Coronary Artery Bypass Grafting; Mortality; Oman
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