Intussusception in Childhood: The Role of Plain Abdominal Radiographs

Symplectic Embedding and Hamilton–jacobi Analysis of Proca Model

“…Correspondingly they did not obtain the desired Wess-Zumino Lagrangian. On the other hand, our procedure treating π θ as an independent field, led in a natural way to the Stückelberg Lagrangian, in agreement with earlier calculations using the improved DQM [19]. Similar to the WZ term case, we introduced the additional ghost and antighost fields together with the auxiliary fields in the symplectic scheme to construct the BRST invariant gauge-fixed Lagrangian and its nilpotent BRST transformation rules.…”

“…That this approach is of particular advantage in the case of first-order Lagrangians such as Chern-Simons theories has been emphasized by Faddeev and Jackiw [16]. This symplectic scheme has been applied to a number of models [17,18] and has recently been used to implement the improved DQM embedding program in the context of the symplectic formalism [19,20].…”

Optical properties of Tm-doped GaSe single crystals

“…Optical studies have been made on photoluminescence [6][7][8] of Mn-and Cr-doped GaSe and on the excitonic emission [9] and thermodepolarization [10] of Co-doped GaSe. The miscibility gap of Cr 3þ in GaSe has been investigated [11]. To our knowledge, however, there are no reports concerning doping of rare-earth elements in GaSe.…”

Lagrange versus symplectic algorithm for constrained systems

“…Faddeev and Jackiw [2] have thus proposed an alternative method based on a first order Lagrangean (symplectic) formulation, avoiding the introduction of primariy constraints. Furthermore, the local symmetries of the Hamiltonian, as generated by the so called "first-class" constraints in Dirac's terminology, turn out to be larger than those of the Lagrangean This has led to a renewed interest in the problem of deducing the local symmetries of a Lagrangean from the Hamiltonian formalism [3], and in particular to a revival of the "Lagrangean approach", and the "symplectic approach" to constrained systems [4,5,6,7,8,9]. Of all three methods, the Lagrangean algorithm is actually the most pedestrian one, with a solid mathematical basis.…”