#### Filter Results:

- Full text PDF available (9)

#### Publication Year

2003

2011

- This year (0)
- Last five years (0)

#### Publication Type

#### Co-author

#### Publication Venue

#### Key Phrases

Learn More

We present analytic computational tools that permit us to identify, in an automatic way, conservation laws in optimal control. The central result we use is the famous Noether's theorem, a classical theory developed by Emmy Noether in 1918, in the context of the calculus of variations and mathematical physics, and which was extended recently to the more… (More)

A two-dimensional body moves through a rarefied medium; the collisions of the medium particles with the body are absolutely elastic. The body performs both translational and slow rotational motion. It is required to select the body, from a given class of bodies, such that the average force of resistance of the medium to its motion is maximal. There are… (More)

- Carlos Capela, Paulo Gouveia, Marco Sousa, Maria J Regadas
- Journal of medical case reports
- 2011

INTRODUCTION
Swyer-James-MacLeod syndrome or unilateral hyperlucent lung syndrome is a rare entity associated with postinfectious bronchiolitis obliterans occurring in childhood. It is characterized by hypoplasia and/or agenesis of the pulmonary arteries resulting in pulmonary parenchyma hypoperfusion.
CASE PRESENTATION
Here we report the case of a… (More)

We use a computer algebra system to compute, in an efficient way, optimal control variational symmetries up to a gauge term. The symmetries are then used to obtain families of Noether's first integrals, possibly in the presence of nonconservative external forces. As an application, we obtain eight independent first integrals for the sub-Riemannian nilpotent… (More)

- P Paixāo, S Almeida, P Gouveia, L Vilarinho, R Vaz Osório
- Euro surveillance : bulletin Européen sur les…
- 2009

Human cytomegalovirus (HCMV) is considered the most frequent cause of congenital infection, occurring in 0.2 to 2.2% of all live births. Since this is a wide range of prevalences observed in different studies, it would be desirable to investigate the prevalence of this infection at national level. The aim of this study was the evaluation of the national… (More)

We give a new computational method to obtain symmetries of ordinary differential equations. The proposed approach appears as an extension of a recent algorithm to compute variational symmetries of optimal control problems [Comput. and is based on the resolution of a first order linear PDE that arises as a necessary and sufficient condition of invariance for… (More)

We use a computer algebra system to compute, in an efficient way, optimal control variational symmetries up to a gauge term. The symmetries are then used to obtain families of Noether's first integrals, possibly in the presence of nonconservative external forces. As an application, we obtain eight independent first integrals for a sub-Riemannian nilpotent… (More)

We report a clinical case of severe malaria, where the rate of initial parasitaemia by Plasmodium falciparum was 43 %. Multiple organ dysfunction, including ARDS, forced admission in a close surveillance unit, with survival of the same. A brief review of the subject is made, focusing on severity and general conduct, alerting and awareness for this entity,… (More)

We study Smarandache sequences of numbers, and related problems, via a Computer Algebra System. Solutions are discovered, and some conjectures presented.

- Paulo D. F. Gouveia, Alexander Plakhov, Delfim F. M. Torres
- Applied Mathematics and Computation
- 2009

A two-dimensional body, exhibiting a slight rotational movement, moves in a rarefied medium of particles which collide with it in a perfectly elastic way. In previously realized investigations by the first two authors, Plakhov & Gouveia (2007, Nonlinearity, 20), shapes of nonconvex bodies were sought which would maximize the braking force of the medium on… (More)