Browsing by Author "Lopes, Isabel"
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- Development and validation of an experimental life support system for assessing the effects of global climate change and environmental contamination on estuarine and coastal marine benthic communitiesPublication . Coelho, Francisco J. R. C.; Rocha, Rui J. M.; Pires, Ana C. C.; Ladeiro, Bruno; Castanheira, Jose M.; Costa, Rodrigo; Almeida, Adelaide; Cunha, Angela; Lillebo, Ana Isabel; Ribeiro, Rui; Pereira, Ruth; Lopes, Isabel; Marques, Catarina; Moreira-Santos, Matilde; Calado, Ricardo; Cleary, Daniel F. R.; Gomes, Newton C. M.An experimental life support system (ELSS) was constructed to study the interactive effects of multiple stressors on coastal and estuarine benthic communities, specifically perturbations driven by global climate change and anthropogenic environmental contamination. The ELSS allows researchers to control salinity, pH, temperature, ultraviolet radiation (UVR), tidal rhythms and exposure to selected contaminants. Unlike most microcosms previously described, our system enables true independent replication (including randomization). In addition to this, it can be assembled using commercially available materials and equipment, thereby facilitating the replication of identical experimental setups in different geographical locations. Here, we validate the reproducibility and environmental quality of the system by comparing chemical and biological parameters recorded in our ELSS with those prevalent in the natural environment. Water, sediment microbial community and ragworm (the polychaete Hediste diversicolor) samples were obtained from four microcosms after 57days of operation. In general, average concentrations of dissolved inorganic nutrients (NO3-; NH4+ and PO4-3) in the water column of the ELSS experimental control units were within the range of concentrations recorded in the natural environment. While some shifts in bacterial community composition were observed between in situ and ELSS sediment samples, the relative abundance of most metabolically active bacterial taxa appeared to be stable. In addition, ELSS operation did not significantly affect survival, oxidative stress and neurological biomarkers of the model organism Hediste diversicolor. The validation data indicate that this system can be used to assess independent or interactive effects of climate change and environmental contamination on benthic communities. Researchers will be able to simulate the effects of these stressors on processes driven by microbial communities, sediment and seawater chemistry and to evaluate potential consequences to sediment toxicity using model organisms such as Hediste diversicolor.
- A influência das práticas parentais no sucesso escolar de adolescentes imigrantes e portuguesesPublication . Lopes, Isabel; Nunes, CristinaEste trabalho teve como objetivo observar e analisar as relações entre as práticas educativas parentais e o sucesso académico dos adolescentes. Participaram neste estudo 155 adolescentes divididos em dois grupos: portugueses e imigrantes. Os instrumentos utilizados foram Dados sociodemográficos (Nunes, Lemos, & Guimarães, 2011), e Técnicas Parentais Positivas: foram usados seis itens do Alabama Parenting Questionnaire (Shelton, Frick, & Wootton, 1996), sendo recolhidos dados sobre o adolescente e o seu contexto familiar, bem como indicadores de sucesso académico. Neste estudo fez-se ainda uma breve referência à populaçao em estudo: adolescentes imigrantes e respetivo sucesso escolar em Portugal. Concluimos que o reforço positivo, o apoio parental e o acompanhamento dos educandos revelou uma forte correlação com o sucesso académico do adolescente. Para esta investigação foram fundamentais os autores citados, bem como a estreita colaboração dos pais com os seus adolescentes, independentemente de estes serem ou não imigrantes.
- Potential protective role of amphibian skin bacteria against water mold saprolegnia spp.Publication . Costa, Sara; Proença, Diogo Neves; Alves, Artur; Morais, Paula V.; Lopes, IsabelAmphibian populations have experienced a severe decline over the past 40 years, driven primarily by environmental pollution, habitat destruction, climate change, and disease. This work reports, for the first time, saprolegniosis in Pelophylax perezi egg masses and saprolegniosis in amphibians in Portugal. After isolation and phylogenetic analysis, the pathogen was identified as Saprolegnia australis. Following this, the present work intended to screen a collection of P. perezi skin bacteria for the existence of bacterial strains with inhibitory action against the newly identified S. australis SC1 and two other species, Saprolegnia diclina SAP 1010 UE and Saprolegnia australis SAP 1581 UE. The results showed that various bacterial species could inhibit the growth of these three species of oomycetes. Bacteria with the most significant antagonistic action against Saprolegnia spp. predominantly belonged to the genus Bacillus, followed by Serratia, Pseudomonas, and Aeromonas. Despite variations in bacterial diversity among frog populations, the present study also demonstrated the presence of bacteria on frogs’ skin that were capable of inhibiting Saprolegnia spp., as evidenced by in vitro challenge assays. These findings highlight the protective function of bacteria present in amphibian skin. The observed bacterial diversity may contribute to the metabolic redundancy of the frog skin microbiome, helping to maintain its functional capacity despite shifts in the community composition. Additionally, the study found that, when providing a more advantageous environment for pathogen growth—in this case a peptone–glucose (PG) medium instead of R2A—the percentage of bacteria with moderate-to-strong antagonistic activity dropped by 13% to 4%. In conclusion, the presence of bacteria capable of inhibiting Saprolegnia spp. in adult individuals and across different environmental conditions may contribute to lowering the susceptibility of frog adults towards Saprolegnia spp., compared with that in the early stages of development, like the tadpole or egg stages.
- Prediction of low frequency sound fields in buildings near railway linesPublication . Neves e Sousa, Albano; Lopes, Isabel; Carreira, A. S.The design of new buildings in the vicinity of railway lines must consider protection against noise and vibrations induced by railway traffic. However, the prediction methods available involve heavy numerical models which have frequency limitations. In this paper a prediction method combining finite elements (FEM) with natural mode analysis is presented for use in reinforced concrete buildings with heavy walls. The method considers 2D FEM models of the railway, ground and buildings to identify the transfer function of vibration from the railway to building foundations. Also 3D models of the buildings are considered to identify the transfer functions of vibration from foundations to walls and floors. Finally, as the impedance of heavy walls and floors is much higher than the acoustic impedance of air, the numerically assessed vibration fields of walls and floors are used to calculate sound fields in rooms by means of natural mode analysis. A set of in situ measurements were made in two different situations in order to calibrate the prediction method and also to identify the factors which most affect vibration and sound transmission.