Browsing by Author "Machado, A."
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- Ability of salt marsh plants for TBT remediation in sedimentsPublication . Carvalho, P. N.; Basto, M. C.; F. G. M. Silva, Manuela; Machado, A.; Bordalo, A.; Vasconcelos, M. T.The capability of Halimione portulacoides, Spartina maritima, and Sarcocornia fruticosa (halophytes very commonly found in salt marshes from Mediterranean areas) for enhancing remediation of tributyltin (TBT) from estuarine sediments was investigated, using different experimental conditions.
- Efficiency of triple emitter source (TES) for irrigation experiments of horticultural cropsPublication . Beltrão, José; Jesus, S. B.; Silva, V.; Sousa, P. B.; Carvalho, Isabel Saraiva de; Trindade, D.; Rodrigues, M. H.; Machado, A.Triple emitter source TES experimental irrigation was designed. Three trickle laterals were connected together in order to form a triple joint lateral. Two of them and their emitters are connected to two tanks of stock solutions. The third lateral contains only fresh water. The emitters of the two solution lines have different and varying discharges to obtain several mixings of the two stock solutions. The third line is necessary to obtain constant water application rates for each trickling point along the lateral. This method was tested for several experiments involving the study of the combined effects of salinity and fertilizers on the yield function of horticultural crops, namely lettuce and cabbage. As concluding remarks, it was shown the high uniformity of the factor to be evaluated, through the use of Christiansen coefficient of uniformity distribution CUC, which value was always larger than 90%. Main advantage of this experimental design is its smaller experimental plots (reducing pollution and research costs).
- Geochemical characterization of surficial sediments from the southwestern Iberian continental shelfPublication . Machado, A.; Rocha, F.; Araujo, M. F.; Vitali, F.; Gomes, C.; Dias, João A.The impact of trace elements (Ba, Nb, Zr, Y, Sr, Rb, Pb, As, Zn, Cu, Ni, Co, Cr, V, La, Ce, Nd, Sm, Eu, Th, Yb and Lu) transported by the Guadiana, Tinto-Odiel and Guadalquivir rivers on sediments from the southwestern Iberian continental shelf has been studied. Shelf surficial sediments from three transects established right in front of the river estuaries were characterized by specific signatures relative to those trace elements. The Guadiana transect shows high Zr concentration values; the Tinto-Odiel transect shows high heavy metal (Pb, As, Zn and Cu) concentration values; and the Guadalquivir transect shows high Sr concentration values. Data from the statistical analysis indicate three distinct sources for trace elements: lithogenic, biogenic and anthropogenic.