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- Sabino Jos, E Ferreira, Alan D Sokal
- 1994

We study the antiferromagnetic q-state Potts model on the square lattice for q = 3 and q = 4, using the Wang-Swendsen-Koteck y Monte Carlo algorithm and a new nite-size-scaling extrapolation method. For q = 3 we obtain good control up to correlation length 5000; the data are consistent with () = Ae 2 (1 + a 1 e +. . .) as ! 1. For q = 4 the model is… (More)

Many problems in adaptive control can be divided into two parts; the first part is the control of plant dynamics, and the second is the control of plant disturbance. Very often, a single system is utilized to achieve both of these control objectives. The approach of this paper treats each problem separately. Control of plant dynamics can be achieved by… (More)

- E Gotsman, E Ferreira, +4 authors Beverly Sackler
- 2000

We expect that s-channel unitarity should materialize in hard DIS reactions through screening corrections (SC) indicating that the gluon distribution function is approaching saturation, it is not as yet clear what the kinematical scales are at which these effects become important. While the global DIS γ * p total cross section, or F 2 (x, Q 2), data are… (More)

- H. G. Dosch, E. Ferreira
- 2009

We discuss various aspects of vector meson production, first analysing the interplay between perturbative and nonperturbative aspects of the QCD calculation. Using a general method adapted to incorporate both perturbative and nonpertubative aspects, we show that nonperturbative effects are important for all experimentally available values of the photon… (More)

- R S Marques De Carvalho, F S Navarra, M Nielsen, E Ferreira, H G Dosch
- 1999

QCD sum rules for the determination of form factors of Λ b and Λ c semilep-tonic decays are investigated. With a form for the baryonic current appropriate for the limits of the heavy quark symmetries, the different tensor structures occurring in the two-and three-point functions are separately studied, and in each case general relations are written for the… (More)

- H G Dosch, E Ferreira, M Nielsen, R Rosenfeld
- 1997

We set up sum rules for heavy lambda decays in a full QCD calculation which in the heavy quark mass limit incorporates the symmetries of heavy quark effective theory. For the semileptonic decay of the Λ b we find at the zero recoil point a violation of the heavy quark symmetry of more than 20%. We test the method by calculating the decay width of the… (More)

- S Nogueira, E Ferreira, D Geisinger, C San Román, H Suarez
- Conference proceedings : ... Annual International…
- 2010

In this study a simple model of the postural control system is implemented and its parameters are adjusted to explain the differences between Parkinson's disease patient's measures and healthy young adult's measures by performing simulations of spontaneous sway with center-of-pressure traces. An optimization procedure was performed varying four parameters… (More)

- Ricardo Vieira Botelho, Edson Denner Zandonadi Ferreira, Helton Portela Santos, Rodolfo de Moura Carneiro, Emilio Afonso França Fontoura
- 2011

The role of transfacetary screw in cervical spine surgery: technical note Since the rst description of cervical spine screw xation, techniques using sublaminar wire xation are intended to the rare cases with non-vertebral bone anchorage. Screw xation systems has gained widespread use in recent times. The techniques of lateral mass xation, cervical pedicle… (More)

- E. Ferreira
- 2013

Presently, the characterization of metal materials is becoming increasingly important due to the development of new materials, which is often performed numerically. Therefore, the accuracy of software simulation totally depends on the quality of the constitutive models and of their parameters. Hence, in this work, it is performed a loading path which allows… (More)

- E Gotsman, E Ferreira, +4 authors Beverly Sackler
- 2008

We examine the latest HERA experimental measurements of the Q 2 logarithmic derivative of the proton structure function. We analyze the characteristics of DGLAP with and without screening, as well as a Regge type model, and compare their predictions to all available data on ∂F 2 ∂ ln Q 2 including those for fixed W. Our results show that the present data… (More)

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