We describe gauge-fixing at the level of virtual paths in the path integral as a non-symplectic BRST-type of flow on the path phase space. As a consequence a gauge-fixed, non-local sym-plectic structure arises. Restoring of locality is discussed. A pertinent anti-Lie-bracket and an infinite dimensional group of gauge fermions are introduced. Generalizations to Sp(2)-symmetric BLT-theories are m...

We demonstrate that in a certain gauge the Lax matrices of the rational and hyperbolic Ruijsenaars–Schneider models have a quadratic r-matrix Poisson bracket which is an exact quadratization of the linear r–matrix Poisson bracket of the Calogero–Moser models. This phenomenon is explained by a geometric derivation of Lax equations for arbitrary flows of both hierarchies, which turn out to be gov...

introduced in 1991 to save the clinician the time spent in preparing the adhesive for direct bonding and applying it to the bracket.1 The APC brackets, which are packaged in individual capsules for ease of identification and infection control, are applied with finger pressure.2 A uniform factory precoating purportedly ensures an even amount and consistency of composite beneath each bracket. Any...

BACKGROUND The aim of this study is to calculate and compare the play and torque expression of 0.018 and 0.022 bracket slots when engaged with archwires of different size, cross section and material. METHODS Eight orthodontic brackets, two of slot height 0.018 and six of slot height 0.022, from different manufacturers, were measured and fixed to a vertical support. Twenty-four archwires of di...

Starting from the Kac–Moody structure of the WZNW model for SL(2, R) and using the general canonical formalism, we formulate a gauge theory invariant under local SL(2, R)× SL(2, R) and diffeomorphisms. This theory represents a gauge extension of the WZNW system, defined by a difference of two simple WZNW actions. By performing a partial gauge fixing and integrating out some dynamical variables,...

Appearance does count at any age. Esthetic compromise repels adult patients from accepting traditional metallic look orthodontic treatment. Tooth colored brackets and wires gained popularity for a few decades but gradually declined owing to its own disadvantages. Lingual orthodontic appliances brought paradigm shift, but could not got prevalent because of tedious bracket positioning, insufficie...

It is difficult to visualize the lingual surfaces of the all tooth, in order to assess the exact Facial axis of the clinical crown (FACC point) . So no matter how accurately brackets are positioned on set-up models, it would be meaningless if these positions were lost during intraoral bracket placement. It is no exaggeration to say that incorrect bracket positioning leads to treatment failure. ...

one of the most important problems in geodesy is the unification of height datum. generally in geodesy; there are two types of height systems, the geometrical height based on ellipsoid and the physical height based on gravity-defined surface (zhang et al, 2009).local height datum is determined according to mean sea level (msl). in regarding to mismatch of mean sea level and geoid, on the one ha...

We express the difference between Poisson bracket and deformed bracket for Kontsevich deformation quantization on any Poisson manifold by means of second derivative of the formality quasiisomorphism. The counterpart on star products of the action of formal diffeomorphisms on Poisson formal bivector fields is also investigated. Mathematics Subject Classification (2000) : 16S80, 53D17, 53D55, 58A50.

We consider (2+1)-gravity with vanishing cosmological constant as a constrained dynamical system. By applying Dirac’s gauge fixing procedure, we implement the constraints and determine the Dirac bracket on the gauge-invariant phase space. The chosen gauge fixing conditions have a natural physical interpretation and specify an observer in the spacetime. We derive explicit expressions for the res...