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Food-Limited Growth And Condition Index In The Eastern Oyster, Crassostrea Virginica (Gmelin, 1791), And The Bay Scallop, Argopecten Irradians Irradians (Lamarck, 1819), Michael A. Rice, Robert B. Rheault Jr.

Michael A Rice

The growth response of the eastern oyster, Crassostrea virginica, and the bay scallop, Argopecten irradians irradians, to varying degrees of food limitation was evaluated. Under conditions of low current speed, dense assemblages of shellfish can rapidly deplete ambient food concentrations, resulting in measurable effects on growth and condition index. A flume study demonstrated significant growth and condition index responses to resource competition after reductions as small as 27% in relatively high ambient food concentrations (—4.6 u.g/1 chlorophyll). Growth rates and condition index are linearly correlated with the average chlorophyll ration consumed. A field study demonstrated similar growth responses when the …

Un Modelo De Equilibrio General Dinámico Del Impuesto Al Activo, Rodrigo Garcia-Verdu

Rodrigo Garcia-Verdu

Technological Specialization And Economic Performance In Oecd Countries, Mario Pianta, Valentina Meliciani

Mario Pianta

The paper investigates the growing sectoral specialization in technological activities of OECD countries (measured using patent data) and its impact on countries' innovative and economic performance in the 1975-1990 period. Aggregate indicators of sectoral specialization are introduced, showing the extent to which countries concentrate their innovations in few fields, or spread them across several sectors. A general positive relationship is found between the degree of specialization in technology and higher rates of growth, while specialization in electronics-related fields is not associated to better economic or technological performances. The position of individual countries in these patterns is also examined, showing that …