Browsing by Issue Date, starting with "2013-01"
Now showing 1 - 10 of 17
Results Per Page
Sort Options
- Biomarkers in nereis diversicolor (Polychaeta: Nereididae) as management tools for environmental assessment on the southwest Iberian coastPublication . Gomes, Tânia; Gonzalez-Rey, Maria; Rodriguez-Romero, Araceli; Trombini, Chiara; Riba, Immaculada; Blasco, Julian; Bebianno, Maria JoãoThe environmental quality of the southwest Iberian coast was assessed in different areas (Ria Formosa Lagoon, Guadiana Estuary and Cadiz Bay) focusing on metal contamination (Cd, Cu, Ni, Pb and Zn) in Nereis diversicolor whole tissues. In addition, associated toxicological effects were assessed using a multibiomarker approach combining several conventional biomarkers. The set of biomarkers selected included antioxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase), metallothionein and lipid peroxidation. N. diversicolor from the Ria Formosa Lagoon, Guadiana River and Cadiz Bay responded differently to metal contamination with different biomarker responses showing a clear site trend, suggesting different sources and/or magnitudes of contamination. Cadmium was a source of oxidative stress in polychaetes, mainly in Cadiz Bay, with a significant influence on antioxidant enzymes and enhancement of lipid peroxidation. The highest MT concentrations were in the Ria Formosa Lagoon and in the Guadiana River, where there was a direct relationship with high nickel concentrations. Biomarker responses of N. diversicolor are useful tools for environmental quality assessment on the southwest Iberian coast, and more specific metal biomarkers should be included in future assessments.
- Implications of complexity and sustainability in civil engineeringPublication . Pires Rosa, ManuelaThere is an awareness in the western world that the synergetic effects of the economic and technological growth have caused important environmental, ecological and social problems, at a local, regional and global scale. This perception is raising the emergency of new perspectives – such as sustainability and resilience – which are expressed in new dynamics of social and political transformation. In these latter domains, social and academic movements have been proclaiming the need of a New Economy, of a New Urbanism and of a New Mobility. Simultaneously, deep epistemological changes are occurring which require new ways of thinking and new values which claim holistic and ecosystem approaches. The above mentioned realities will imply profound changes in the development of Civil Engineering, namely in the scientific areas of Land Use Planning, of Water Management and of Mobility Management, which demand “predict and prevent” approaches to reduce the search of natural resources. In processual terms, the Civil Engineer must adapt to the present process of change, needing to conjugate his activity to the activity of other professionals and to other communities, in terms of participated planning and adaptive management.
- Erratum - A remark on Rasmussen's Invariant of knots (vol 16, pg 333, 2007)Publication . Mackaay, Marco; Turner, P.; Vaz, P.
- Manuel da Fonseca. A escrita do fogo e das cinzas do humanoPublication . Carmo, Carina Infante doManuel da Fonseca é na primeira hora neo-realista um dos escritores que mais rapidamente chegou ao apuro da escrita, comprovada na poesia, com Rosa dos Ventos (1940) e Planície (1941), e na narrativa, com Aldeia Nova (1942) e Cerromaior (1943). A colaboração em jornais e revistas (em particular em O Diabo), nos anos de 1938 e 1939, impulsionou a afirmação dessa sua obra inicial que investiu desde logo numa geografia sentimental privilegiada, o Alentejo.
- Interspecific variability of endocrine disruption and oxidative stress in two bivalve species from the Ria Formosa Lagoon (south coast of Portugal)Publication . Pereira, Catarina; Gomes, Tânia; Cardoso, Catia; Almeida, Ana Catarina; Araújo, Olinda; Bebianno, Maria João; Cravo, AlexandraEstuaries are highly productive ecosystems that have been increasingly affected by anthropogenic activities. In this study, the presence of endocrine disrupting compounds (EDCs) and their relation to oxidative stress were assessed in two bivalve species (mussels Mytilus galloprovincialis and clams Ruditapes decussatus) from the Ria Formosa Lagoon (south Portugal). We applied the alkali-labile phosphate (ALP) assay to determine vitellogenin-like protein levels, and the lipid peroxidation (LPO) method to assess oxidative damage. Mussels and clams exhibited the same pattern of ALP concentrations, with no differences between genders and higher levels in winter. R. decussatus showed higher ALP values than M. galloprovincialis, possibly associated with a stronger responsiveness of clams to EDCs or due to the influence of the reproductive cycle. Mussels exhibited a more evident seasonal effect for LPO, indicating that these organisms are more influenced by seasonal fluctuations in the water column compared to the sediment-associated clams. Both species appear to be under the influence of EDC exposure (which could induce Vg-like protein synthesis) and oxidative stressors (leading to lipid peroxidation) in the Ria Formosa Lagoon, particularly in winter, reflecting the presence of different contaminants in Ria Formosa and environmental changes, as well as complex interactions between them.
- Mantle dynamics and characteristics of the Azores plateauPublication . Adam, C.; Madureira, P.; Miranda, M; Lourenço, Nuno; Yoshida, M.; Fitzenz, D.Situated in the middle of the Atlantic Ocean, the Azores plateau is a region of elevated topography encompassing the triple junction between the Eurasian, Nubian and North American plates. The plateau is crossed by the Mid-Atlantic Ridge, and the Terceira Rift is generally thought of as its northern boundary. The origin of the plateau and of the Terceira Rift is still under debate. This region is associated with active volcanism. Geophysical data describe complex tectonic and seismic patterns. The mantle under this region is characterized by anomalously slow seismic velocities. However, this mantle structure has not yet been used to quantitatively assess the influence of the mantle dynamics on the surface tectonics. In this study, we use a highly resolved tomography model to model the convection occurring in the mantle beneath the Azores region. The convection pattern points out two distinct upwelling, thus proving that the volcanism emplacement is created by a buoyant mantle upwelling. The modeled dynamic topography recovers well the characteristics of the depth anomaly associated with the Azores plateau, except for the south-eastern most part, thus proving that most of the depth anomaly associated with the Azores plateau is created by the present-day mantle dynamics. The stresses induced by the mantle convection can account for the lifting regime observed over the Azores plateau and the Terceira Rift, and its consequences in terms of surface morphology and seismicity. (C) 2012 Elsevier B.V. All rights reserved.
- Specific absorption coefficient of phytoplankton off the Southwest coast of the Iberian Peninsula: a contribution to algorithm development for ocean colour remote sensingPublication . Goela, Priscila; Icely, John; Cristina, Sónia; Newton, Alice; Moore, Gerald; Cordeiro, ClaraThe variability in coefficients of absorption for phytoplankton was assessed for an area off the Southwest coast of Portugal. This area included three sites at 2, 10 and 18 km perpendicular to the coast, sampled at surface, mid-Secchi and Secchi depths at each site. Phytoplankton absorption coefficients were transformed into specific coefficients (a⁎ph(λ)) by normalizing them with respect to chlorophyll a (Chla) concentrations determined by High Performance Liquid Chromatography. The influence on the variability of the absorption coefficient of phytoplankton was assessed for physico-chemical and biological parameters such as nutrients or Chla levels, as well as size structure and abundance of the phytoplankton community. The results showed that the phytoplankton absorption coefficients decreased from inshore to offshore, but were relatively constant within the water column, revealing a well-mixed column. The a⁎ph(λ) varied inversely with Chla content, with minima in Autumn and Spring, matching phytoplankton blooms. The effects of the size structure of the community and pigment composition on the variability of phytoplankton absorption coefficient were studied and results showed that size structure had a greater influence on the variability of the phytoplankton absorption, although the pigment contribution was also important.
- Caderno de exercícios para Teoria da Ligação QuímicaPublication . Wang, WenliCaderno de Exercícios para a disciplina "Teoria da Ligação Química" ano lectivo 2012/2013
- Sebenta das aulas teóricas para 'Teoria da Ligação Química'Publication . Wang, WenliSebenta das Aulas Teóricas para disciplina de "Teoria da Ligação Química"
- New aspect in seagrass acclimation: leaf mechanical properties vary spatially and seasonally in the temperate species Cymodocea nodosa Ucria (Ascherson)Publication . de los Santos, Carmen B.; Brun, Fernando G.; Vergara, Juan J.; Pérez-Lloréns, J. LucasSeagrasses may acclimate to environmental heterogeneity through phenotypic plasticity. In contrast to leaf morphology, which has been a central point in seagrass acclimation studies, plasticity in leaf biomechanics and fibre content is poorly understood, despite being crucial in plant ecological performance, especially regarding physical forces. We hypothesised that mechanical traits (e.g. breaking force, strength, toughness, and stiffness) and fibre content of seagrass leaves vary as morphology does under differential environments. Cymodocea nodosa was seasonally monitored at three locations around Ca´diz Bay (southern Spain) with hydrodynamic regime as the most noticeable difference between them. Leaves showed plasticity in both morphology and mechanical traits, with wave-exposed individuals presenting short but extensible and tough leaves. Leaf fibre content was invariant along the year and with little spatial variability. Cross-sectional area rather than material properties or fibre content differentiates leaf mechanical resistance. Seagrass capacity to thrive under a range of mechanical forces may be dictated by their plasticity in morpho-biomechanical traits, a key element for the hydrodynamical performance and, hence, for species colonisation and distribution.