Ontogeny of swimming capacity in plaice (Pleuronectes platessa) larvae

Little is known regarding the swimming ability of the larvae of European plaice (Pleuronectes platessa) in relation to changes in total length (TL), dry weight (DW) and developmental stage, which is surprising given the importance of transport processes to the recruitment dynamics of this species in the North Sea and elsewhere. We investigated ontogenetic changes in the critical swimming speed (Ucrit) of plaice from hatching to the onset of metamorphosis (50 days post-hatch, dph) at 8 ��C. The mean (��SD) TL and DW growth rates were 1.59 �� 0.81 and 7.7 �� 0.35 % d���1, respectively. Larvae were unable to swim at against a minimum current speed of <0.5 cm s���1 until 10 dph (7 mm TL), after which Ucrit significantly increased with increasing TL until the onset of metamorphosis and subsequent settlement. Mean (��SD) Ucrit was 0.38(0.35), 1.59(0.54), 2.27(0.49) and 2.99(0.37) cm s���1 for stage I (6.61 �� 2.64 mm TL), stage II (7.75 �� 0.60 mm TL), stage III (9.10 �� 1.00 mm TL) and stage IV (11.59 �� 0.85 mm TL) larvae, respectively. Larval TL, DW, DNA content, RNA content and Ucrit significantly increased, whereas sRD significantly declined as larvae developed from stage I to V. Although inter-individual differences in Ucrit (coefficient of variation, CV = 33 %) were as large as those in biochemical and morphological condition (CV���s of 21���42 %), differences in Ucrit were not significantly related to those in nutritional condition and larvae with lower DNA/DW had also better swimming abilities. These estimates should be useful to ongoing efforts to create individual- based models of the transport, foraging and growth of plaice larvae in the North Sea.

Invent��rio de Medos III : Avalia����o das qualidades psicom��tricas em uma amostra portuguesa

Este estudo teve como objetivo avaliar as qualidades psicom��tricas do Fear Survey Schedule-III, em uma amostra portuguesa. Participaram 1.980 sujeitos selecionados por conveni��ncia a partir de uma popula����o adulta normativa. As idades dos participantes estavam compreendidas entre os 18 e os 80 anos (M = 39,5, DP = 8,5), sendo 59% do sexo feminino. As qualidades psicom��tricas da escala foram avaliadas em suas facetas de sensibilidade psicom��trica, validade de construto e confi abilidade. A validade externa de construto foi avaliada com an��lise multigrupos em amostra aleat��ria e independente da amostra de valida����o inicial. O modelo fatorial original proposto apresentou um ajustamento inaceit��vel �� amostra de valida����o. Procedeu-se ao refi namento do modelo de medida em uma parte da amostra, selecionada aleatoriamente. Em conclus��o, o modelo de medida simplifi cado apresentou uma boa qualidade de ajustamento fatorial e foi invariante em uma segunda amostra independente da primeira. Prop��s-se uma nova estrutura hier��rquica, com fator de 2�� ordem designado por ���Medos���, que revelou boas qualidades psicom��tricas (sensibilidade, validade de construto e confi abilidade).