7,999 research outputs found
Decays into -Vector
A complete study of the angular distributions of the processes, , with and or is performed.
Emphasis is put on the initial polarization produced in the
proton-proton collisions. The polarization density-matrices as well as angular
distributions are derived and help to construct T-odd observables which allow
us to perform tests of both Time-Reversal and CP violation.Comment: 10 pages, 2 figure
Angular Analysis of Lambda_b Decays into Lambda v(1-) Applications to Time-Odd Observables and CP violation in Lambda_b Decays (I)
A complete study of teh angualr distributions of the process Lambda_b to
Lambda V(1-) with lambda to p pi- and V(J/Psi) to l+l- or V(rho0,omega, phi) to
pi+ pi-, K+K- is performed. Emphasis is put on the initial Lambda-b
polarization produced in the proton-proton collisions and, without any
dynamical assumption, polarized density-matrices of the vector-mesons V are
derived and help to construct T-odd observables which allow us to perform tests
of both Time-Reversal and CP violation.Comment: 12 pages, 2 figure
Improvement of Surface Accuracy and Shop Floor Feed Rate Smoothing Through Open CNC Monitoring System and Cutting Simulation
AbstractIn the milling process of complex workpiece shapes the feed rate normally becomes instable due to the high degree of surface curvature that requires high acceleration and deceleration of the interpolated axes. This condition impacts on process time and on the surface accuracy regarding the manufactured part form and texture. The challenge to simulate the real machine and control behavior requires accurate models with a set of experiments to tune and dimension the model to the respective machine tool. The aim is to improve the HSC milling process of complex surfaces before removing any material. In this paper experiments show that the surface form accuracy and texture can be optimized through an automatic feed rate smoothing of the finishing operation directly on the machine tool. The axis positions and spindle speeds monitored through the open CNC are used as input for a geometric cutting simulation, thus enabling to predict and optimize the surface quality
Construction of Special Solutions for Nonintegrable Systems
The Painleve test is very useful to construct not only the Laurent series
solutions of systems of nonlinear ordinary differential equations but also the
elliptic and trigonometric ones. The standard methods for constructing the
elliptic solutions consist of two independent steps: transformation of a
nonlinear polynomial differential equation into a nonlinear algebraic system
and a search for solutions of the obtained system. It has been demonstrated by
the example of the generalized Henon-Heiles system that the use of the Laurent
series solutions of the initial differential equation assists to solve the
obtained algebraic system. This procedure has been automatized and generalized
on some type of multivalued solutions. To find solutions of the initial
differential equation in the form of the Laurent or Puiseux series we use the
Painleve test. This test can also assist to solve the inverse problem: to find
the form of a polynomial potential, which corresponds to the required type of
solutions. We consider the five-dimensional gravitational model with a scalar
field to demonstrate this.Comment: LaTeX, 14 pages, the paper has been published in the Journal of
Nonlinear Mathematical Physics (http://www.sm.luth.se/math/JNMP/
Cyclic Mobility Effects on Soil-Pile Interaction in Dense Sand
A methodology to evaluate the effects of earthquake-induced cyclic mobility in dense sand on the soil-pile interaction parameters is presented. The soil behavior under cyclic loading is defined based on the interpretation of consolidated-undrained cyclic triaxial tests on samples reconstituted to the in situ relative density and shear wave velocity. The stress distribution around the pile is determined analytically, and the softened zone is modelled by an annulus of softer soil. The application of this methodology for the design of three submerged-floating tunnels in the Messina straits, Italy, indicated that even in dense sand the foundation stiffness reduction can be considerable during an earthquake. Comparisons with different approaches available from the literature are discussed
A reduction of the resonant three-wave interaction to the generic sixth Painleve' equation
Among the reductions of the resonant three-wave interaction system to
six-dimensional differential systems, one of them has been specifically
mentioned as being linked to the generic sixth Painleve' equation P6. We derive
this link explicitly, and we establish the connection to a three-degree of
freedom Hamiltonian previously considered for P6.Comment: 13 pages, 0 figure, J. Phys. A Special issue "One hundred years of
Painleve' VI
Symmetry reductions of a particular set of equations of associativity in twodimensional topological field theory
The WDVV equations of associativity arising in twodimensional topological
field theory can be represented, in the simplest nontrivial case, by a single
third order equation of the Monge-Ampe`re type. By investigating its Lie point
symmetries, we reduce it to various nonlinear ordinary differential equations,
and we obtain several new explicit solutions.Comment: 10 pages, Latex, to appear in J. Phys. A: Math. Gen. 200
Control of mucocutaneous leishmaniasis, a neglected disease: results of a control programme in Satipo Province, Peru.
Mucocutaneous leishmaniasis (MCL) is an important health problem in many rural areas of Latin America, but there are few data on the results of programmatic approaches to control the disease. We report the results of a control programme in San Martin de Pangoa District, which reports one of the highest prevalences of MCL in Peru. For 2 years (2001--2002), the technicians at the health post were trained in patient case management, received medical support and were supplied with antimonials. An evaluation after 2 years showed the following main achievements: better diagnosis of patients, who were confirmed by microscopy in 34% (82/240) of the cases in 2001 and 60% of the cases (153/254) in 2002; improved follow-up during treatment: 237 of 263 (90%) patients who initiated an antimonial therapy ended the full treatment course; improved follow-up after treatment: 143 of 237 (60%) patients who ended their full treatment were correctly monitored during the required period of 6 (cutaneous cases) or 12 (mucosal cases) months after the end of treatment. These achievements were largely due to the human and logistical resources made available, the constant availability of medications and the close collaboration between the Ministry of Health, a national research institute and an international non-governmental organization. At the end of this period, the health authorities decided to register a generic brand of sodium stibogluconate, which is now in use. This should allow the treatment of a significant number of additional patients, while saving money to invest in other facets of the case management
Hyper-complex four-manifolds from the Tzitz\'eica equation
It is shown how solutions to the Tzitz\'eica equation can be used to
construct a family of (pseudo) hyper-complex metrics in four dimensions.Comment: To be published in J.Math.Phy
Psi-series solutions of the cubic H\'{e}non-Heiles system and their convergence
The cubic H\'enon-Heiles system contains parameters, for most values of
which, the system is not integrable. In such parameter regimes, the general
solution is expressible in formal expansions about arbitrary movable branch
points, the so-called psi-series expansions. In this paper, the convergence of
known, as well as new, psi-series solutions on real time intervals is proved,
thereby establishing that the formal solutions are actual solutions
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