ESTM - Artigos em revistas internacionais
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- The weathering ability of higher plants. The case of Ailanthus altissima (Miller) SwinglePublication . Almeida, M. T.; Mouga, T.; Barracosa, P.The growth of higher plants in monuments causes wheathering of the substrata and can be one of the biggest problems for conservators.
- Neutralisation of herbicides. Effects on wall vegetationPublication . Mouga, T. M.; Almeida, M. T.The chemical control of wall vegetation growing on monuments has been stated as a suitable instrument of conservative intervention. However, often the use of herbicides has not been the most suitable, endangering either the environment or the monument in question. In particular, when dealing with limestone monuments, the chemical control has to be made very carefully because all the carbonate rocks are particularly sensitive to the weathering action of acids. Thus. to prevent this damage, two acid herbicides were neutralised with potassium hydroxide. This neutralisation did. in fact, decrease the damage caused by their acidity on the limestone. This paper deals with the effects of these neutralised herbicides on higher plants. Several experiments were made to determine whether the efficiency of the herbicides was affected. Also. the neutralisation did not affect the ability of the herbicides to eliminate the wall vegetation.
- Existence of Verbascum levanticum I. K. Ferguson in PortugalPublication . Mouga, Teresa; Almeida, M. T.The species Verbascum levanticum I. K. Ferguson was introduced as an ornamental in the Botanical Garden of Coimbra, in the 19th century. It became naturalized over restricted areas in the centre of Portugal, colonizing walls, rock fissures and dry land. However, during during the past two years, we have found it growing quite vigorously on some walls in Coimbra. The existence of the species is discussed.
- Zinc and cadmium concentrations in soft tissues of the red swamp crayfish Procambarus clarkii (Girard, 1852) after exposure to zinc and cadmiumPublication . Maranhão, Paulo; Marques, João C.; Madeira, Victor M.C.Zinc and cadmium concentrations in crayfish (Procambarus clarkii) soft tissues (as edible portion) were measured after exposure to zinc and cadmium at 0, 25, 50, or 100 mg/L for 96 h at 10 or 208C, and compared to environmental standards for human consumption. Results demonstrated that no significant change occurred in the concentrations of zinc in soft tissues of crayfish under the given conditions. Net accumulation of cadmium was observed at all experimental exposures, and exceeded the maximum allowed for human consumption only for those crayfish exposed to 100 mg/L at 208C.
- Enzymatic upgrade of old paperboard containersPublication . Pala, Helena; Lemos, M. A.; Mota, Manuel; Gama, Francisco MiguelThe use of enzymes in secondary fiber (old paperboard containers) upgrading was investigated. The following aspects were analyzed: (i) the effect of several enzymes and (non-hydrolytic) cellulose-binding domains on the pulp and paper properties; (ii) factors influencing enzymatic treatment of secondary fiber: enzyme dosage and reaction time; and (iii) enzyme action on fractions with different fiber-length. In general, all the tested enzymatic preparations were able to improve the pulp drainability. In most cases this improvement was obtained at the expense of paper strength. The use of cellulose-binding domains allowed for the simultaneous increase in drainability and strength properties.
- La importancia de la gastronomía en el turismo: Un ejemplo de Mealhada-PortugalPublication . Oliveira, SimãoEl turismo gastronómico está adquiriendo cada vez mayor importancia en Portugal al igual que en muchos países del mundo. Sin embargo, a diferencia de otros destinos el fenómeno no está muy estudiado en Portugal y, en la mayoría de casos, se lo analiza sólo como un elemento asociado al negocio de la hotelería y la restauración. Este trabajo pretende mostrar la importancia de la gastronomía como atracción principal mediante el estudio de caso de la ciudad de Mealhada donde la culinaria es sin duda la razón que motiva el desplazamiento de personas y es la base de la economía local.
- A convergência contabilística nos países lusófonosPublication . Santos, Luís Lima
- Predicting zooplankton response to environmental changes in a temperate estuarine ecosystemPublication . Marques, Sónia Cotrim; Azeiteiro, Ulisses Miranda; Leandro, Sérgio Miguel; Queiroga, Henrique; Primo, Ana Ligia; Martinho, Filipe; Viegas, Ivan; Pardal, Miguel ÂngeloA novel strategy that allows to predict the responses of zooplanktonic species to environmental conditions in an estuarine temperate ecosystem (Mondego estuary) is presented. It uses 12 indicator species from the zooplanktonic Mondego database (102 species) that are common members of the different habitats, characterized by their specific hydrological conditions. Indicator-species analysis (ISA) was used to define and describe which species were typical of each of the five sampling stations in a 4-year study (2003–2006). First, a canonical correspondence analysis (CCA) was carried out to objectively identify the species-habitat affinity based on the relationship between species, stations and environmental data. Response curves for each of the zooplanktonic species, generated by univariate logistic regression on each of the independent variables temperature and salinity, were generally in agreement with the descriptive statistics concerning the occurrence of those species in this particular estuarine ecosystem. Species-specific models that predict probability of occurrence relative to environmental parameters like salinity, water temperature, turbidity, chlorophyll a, total suspended solids and dissolved oxygen were then developed for the zooplanktonic species. The multiple logistic models used contained between 1 and 3 significant parameters and the percentage correctly predicted was moderate to high, ranging from 62 to 95%. The predictive accuracy of the model was assured by direct comparison of model predictions with the observed occurrence of species obtained in 2006 (validation) and from data collected in the early 2000s in another Portuguese estuary - Ria de Aveiro (Canal de Mira), a complex mesotidal shallow coastal lagoon. The regression logistic model here defined, correctly suggested that the distribution of zooplankton species was mainly dependent on salinity and water temperature. The logistic regression proved to be a useful approach for predicting the occurrence of species under varying environmental conditions at a local scale. Therefore, this model can be considered of reasonable application (and should be tested in other estuarine systems) due to its ability to predict the occurrence of individual zooplanktonic species associated with habitat changes.
- The study of bacterioplankton dynamics in the Berlengas Archipelago (West coast of Portugal) using the HJ-biplot methodPublication . Maranhão P.; Mendes, Susana; Fernández-Goméz, M. J.; Galindo-Villardón, M. P.; Azeiteiro, Ulisses; Bacelar-Nicolau, PaulaThe relationship between bacterioplankton and environmental forcing in the Berlengas Archipelago (Western Coast of Portugal) were studied between February 2006 and February 2007 in two sampling stations: Berlenga and Canal, using an HJ-biplot. The HJ-biplot showed a simultaneous display of the three main metabolic groups of bacteria involved in carbon cycling (aerobic heterotrophic bacteria, sulphate-reducing bacteria and nitrate-reducing bacteria) and environmental parameters, in low dimensions. Our results indicated that bacterial dynamics are mainly affected by temporal gradients (seasonal gradients with a clear winter versus summer opposition), and less by the spatial structure (Berlenga and Canal). The yearly variation in the abundance of aerobic heterotrophic bacteria were positively correlated with those in chlorophyll a concentration, whereas ammonium concentration and temperature decreased with increasing phosphates and nitrites concentration. The relationship between aerobic heterotrophic bacteria, chlorophyll a and ammonium reveals that phytoplankton is an important source of organic substrates for bacteria.
- The effect of sewage discharge on Melarhaphe neritoides (Gastropoda: Littorinidae) population dynamicsPublication . Cabral-Oliveira, J.; Maranhão, Paulo; Pardal, M. Â.The discharges of sewage effluent treatment plants has a major impact on coastal communities. In our study area (western coast of Portugal) Melarhaphe neritoides (L. 1758) is the dominant high-shore gastropod. Two populations of M. neritoides were studied in order to understand the impact of sewage discharges on intertidal communities: one popula tion in an impacted area and the other in a similar but unimpacted area (reference site). Environmental data and abundance, biomass, population structure and annual growth production of M. neritoides were estimated in the two areas. The results showed that M. neritoides density is higher in the impacted area as a result of massive settlement. The sewage discharge increases the nutrient concentrations in the water, which causes more microalgae to grow on the rocky surfaces. This higher availability of food may promote recruitment. However, we found high mortality in the juveniles in the impacted area, which affected density values on the upper shore levels (where we found the adults) of both areas. Moreover, the adults were bigger in the unimpacted area, which suggests that individuals grow more or live longer in this area.