63 documents found, page 1 of 7
A pegada do “Ouro Líquido” Mediterrânico nos ecossistemas aquáticos: estudo dos...
Costa, Silvana Teixeira; Miranda, Fernando; Teixeira, Fernando; Zidouh, Aya; Fernandes, Conceição; Dias, Luís; Hernandez, Zulimar; Teixeira, AmílcarAtualmente, 80.000 t de bagaço de azeitona são processadas numa única unidade extratora localizada na região de Trás-os-Montes e Alto Douro, produzindo águas-ruças (OMWW) que são altamente fitotóxicas. A falta de medidas de gestão para este resíduo em específico, levanta a importância de compreender como este pode impactar a integridade ecológica dos ecossistemas aquáticos. Assim, oito locais espalhados pelo Ri...
Girl, what do you want to become when you grow up? Audio-visual creation at school
Miranda, Fernando; Acerbi, GracielaGirl, what do you want to become when you grow up? Filmmaking at school. When does the possibility of the dream of filmmaking appear in women's horizons? If contemporary school is regarded as that time and place suitable for inviting new generations to get involved in the world, it is fair to wonder: what place is given to cinema at school for the new generation of women to imagine themselves being part of the ...
The silent extinction of freshwater mussels in Portugal
Lopes-Lima, Manuel; Reis, Joaquim; Alvarez, Maria G.; Anastácio, Pedro M.; Banha, Filipe; Beja, Pedro; Castro, Paulo; Gama, Mafalda; Gil, Maria G.Freshwater mussels are one of the most threatened animal groups in the world. In the European Union, threatened and protected mussel species are not adequately monitored, while species considered to be common and widespread receive even less attention. This is particularly worrying in the Mediterranean region, where species endemism is high and freshwater habitats are severely affected by water scarcity. In the...
The stability of complex dynamics for two families of coquaternionic quadratic ...
Falcão, M. I.; Miranda, Fernando; Severino, Ricardo; Soares, M. J.In this work, we begin by demonstrating that attractors, both periodic and aperiodic, of the one-parameter family of complex quadratic maps x2+ c, where c is a complex number, maintain their stability when we transition from the complex plane C to the coquaternions Hcoq as the map’s phase space. Next, we investigate the same question for a different family of quadratic maps, x2+ bx, and find that this is not th...
Remarks on the Vietoris sequence and corresponding convolution formulas
Cação, Isabel; Falcão, M. I.; Malonek, Helmuth R.; Miranda, Fernando; Tomaz, GraçaIn this paper we consider the so-called Vietoris sequence, a sequence of rational numbers of the form ck=12k(k⌊k2⌋), k= 0, 1, ⋯. This sequence plays an important role in many applications and has received a lot of attention over the years. In this work we present the main properties of the Vietoris sequence, having in mind its role in the context of hypercomplex function theory. Properties and patterns of the c...
Dynamics of the coquaternionic maps x^2 + bx
Falcão, M. I.; Miranda, Fernando; Severino, Ricardo; Soares, M. J.This paper deals with the dynamics of the one-parameter family of coquaternionic quadratic maps x2+ bx. By making use of recent results for the zeros of one-sided coquaternionic polynomials, the fixed points are analytically determined. The stability of these fixed points is also addressed, where, in some cases, due to the appearance of sets of non-isolated points, a suitably adapted notion of stability is used...
A Two-step Quaternionic Root-finding Method
Falcão, M. I.; Miranda, Fernando; Severino, Ricardo; Soares, M. J.In this paper we present a new method for determining simultaneously all the simple roots of a quaternionic polynomial. The proposed algorithm is a two-step iterative Weierstrass-like method and has cubic order of convergence. We also illustrate a variation of the method which combines the new scheme with a recently proposed deflation procedure for the case of polynomials with spherical roots.
Remarks on the Vietoris sequence and corresponding convolution formulas
Cação, Isabel; Falcão, M. Irene; Malonek, Helmuth R.; Miranda, Fernando; Tomaz, GraçaIn this paper we consider the so-called Vietoris sequence, a sequence of rational numbers of the form ck=12k(k⌊k2⌋), k= 0, 1, ⋯. This sequence plays an important role in many applications and has received a lot of attention over the years. In this work we present the main properties of the Vietoris sequence, having in mind its role in the context of hypercomplex function theory. Properties and patterns of the c...
The silent extinction of freshwater mussels in Portugal
Lopes-Lima, Manuel; Reis, Joaquim; Alvarez, Maria G.; Anastácio, Pedro M.; Banha, Filipe; Beja, Pedro; Castro, Paulo; Gama, Mafalda; Gil, Maria G.Freshwater mussels are one of the most threatened animal groups in the world. In the European Union, threatened and protected mussel species are not adequately monitored, while species considered to be common and widespread receive even less attention. This is particularly worrying in the Mediterranean region, where species endemism is high and freshwater habitats are severely affected by water scarcity. In the...
Monitorização Quadrienal de Nitratos nos Recursos Hídricos Subterrâneos da Zona...
Leitão, Bruno; Nogueira, Abel; Silva, Afonso; Brás, Alda; Duarte, António; Vicente, Ana; Peixoto, André; Matos, António; Miranda, FernandoO Conselho das Comunidades Europeias em 1991, através da Diretiva 91/676/CEE de 12 de dezembro de 1991, reconheceu a importância de proteger as áreas de elevada suscetibilidade para a poluição das águas, causada ou induzida por nitratos (NO3-) de origem agrícola. Uma dessas áreas é a Zona Vulnerável a Nitratos (ZVN) de Esposende -Vila do Conde, criada em 1997 pela Portaria n.º 1037/1997 de 1 de outubro, à data ...