Area preserving nontwist maps, i.e. maps that violate the twist condition, are considered. A representative example, the standard nontwist map that violates the twist condition along a curve called the shearless curve, is studied in detail. Using symmetry lines and involutions, periodic orbits are computed and two bifurcations analyzed: periodic orbit collisions and separatrix reconnection. The...

with z=q+ip, H=| 2T |z| +;1 4T |z| + } } } +;n&1 2nT |z| +r(t, z, z ). The coefficients |, ;1 , ..., ;n&1 are real and r is a T-periodic remainder of order o( |z| ), see [[1], appendice 7]. This is the Birkhoff Normal Form and the numbers ;1 , ..., ;n&1 ,... are the so called twist coefficients. They depend on the derivatives of f (evaluated at % ) up to the order 2n&1 and, when some of them is...

we used qcd factorization for the hadronic matrix elements to show that the existing data, in particular the branching ratios br ( ?j/?k) and br ( ?j/??), can be accounted for this approach. we analyzed the decay within the framework of qcd factorization. we have complete calculation of the relevant hard-scattering kernels for twist-2 and twist-3. we calculated this decays in a special scale ( ...

A quantity, called the linking number, is defined, which specifies the total number of t,wists in a circular helix. The linking number is invariant under continuous deformations of the ring and therefore enables one to calculate the influence of superhelical structures on the secondary helix of a circular molecule. The linking number can be determined by projecting the helix into a plane and co...

In vacuum string field theory, the sliver state solution has been proposed as a candidate of a D-brane configuration. Physical observables associated with this solution, such as its energy density and the tachyon mass, are written in terms of the Neumann coefficients. These observables, though vanish naively due to twist symmetry, acquire non-vanishing values arising from their singular behavio...

A horospherical torus about a cusp of a hyperbolic manifold inherits a Euclidean similarity structure, called a cusp shape. We bound the change in cusp shape when the hyperbolic structure of the manifold is deformed via cone deformation preserving the cusp. The bounds are in terms of the change in structure in a neighborhood of the singular locus alone. We then apply this result to provide info...

We introduce a class of algebras, called twist-structures, whose members are built as special squares of an arbitrary residuated lattice. We show how our construction relates to and encompasses results obtained by several authors on the algebraic semantics of non-classical logics. We define a logic that corresponds to our twist-structures and show how to expand it with modal operators, obtainin...

The C. elegans intestine is a simple tube consisting of a monolayer of epithelial cells. During embryogenesis, cells in the anterior of the intestinal primordium undergo reproducible movements that lead to an invariant, asymmetrical 'twist' in the intestine. We have analyzed the development of twist to determine how left-right and anterior-posterior asymmetries are generated within the intestin...

BACKGROUND Regular training, in particular endurance exercise, induces structural myocardial adaptation, so-called "athlete's heart". In addition to the 2D standard echo parameters, assessment of myocardial function is currently possible by deformation parameters (strain, rotation and twist). Aim of study is to assess the role of rotation and twist parameters for better characterize the heart p...