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63 pages ; Polititapes rhomboides is a commercially exploited species of infaunal clam, endemic in the Galician Rías Baixas. This species, which is not cultured or seeded in any way, has suffered occasional mass mortality episodes and significant fluctuations in captures. Previous studies on mortality events of the species in the Rías Baixas suggest that these were caused by propagation of rickettsia-like intracellular prokaryotes which caused disruption of gill function. Studies also suggested that proliferation of the prokaryote was induced by high temperatures and a weakened health status caused by prolonged adverse meteorological conditions with strong costal agitation which caused enhance bottom turbulence and sediment resuspension. In this context, this work aimed to observe the effect of increased temperature, disturbance of bottom sediment, and a combination of both stressors on several ecophysiological indicators. For this purpose, this study assessed two physiological rates (respiration and clearance rate), condition index, re-burrowing ability after disturbance and immune functional response. Results show that a combination of increased temperature and disturbance increased respiration in clams while clearance rates were increased with warmer temperatures but decreased with disturbance. No significant overall degradation of condition index, re-burrowing ability or immune functional response suggest that clams can tolerate these stressors and quickly recover from disturbance ; No

Nach welchen Kriterien sollte die Führung von Gruppen legitimiert sein? Sollte man eine demokratische Wahl durchführen, per Dekret bestimmen, wer die Führung einer Gruppe übernehmen soll, dies einem Rotationsprinzip überlassen oder gänzlich auf eine formal festgelegte Führerrolle verzichten? Gewiß lassen sich eine Vielzahl wohlbegründeter Argumente zu dieser grundlagentheoretisch wie anwendungsbezogen relevanten Thematik ins Felde führen - eine experimentelle Analyse steht jedoch bislang aus. -- Der Autor löst die Frage der optimalen Legitimation von Führung in diverse Facetten auf und verbindet diese zu einem kohärenten Modell des Gruppenprozesses. Ein umfangreiches Gruppenexperiment vergleicht dann die vier Legitimationsmodi unter verschiedenartigen Bedingungen: Problemlösungs-, Diskussions- und Produktionsaufgaben. Kriterien für Führungserfolg sind dabei neben psychologischen Prozeßvariablen wie Motivation oder empfundener Verunsicherung der Gruppenmitglieder vor allem die Gruppenleistung, die Teilnehmerzufriedenheit, der Zusammenhalt der Gruppe sowie die Akzeptanz der Führung. Unter Zugrundelegung der entsprechenden theoretischen Bezüge wird schließlich dargelegt, wie die gewonnenen Befunde in Überlegungen zur Gestaltung betrieblicher Arbeitsgruppen einfließen können

Investigates whether the pre-conditions for an economic and monetary union in the European Community have been created through the establishment of the European Monetary System in 1979. Summary in Italian.

Several major hypotheses have been proposed to explain and predict the effect of migration on fertility. This article conducts a highly disaggregated analysis of migrant and stayer fertility, using Brazilian data for 1976, to ascertain the extent to which the observed patterns of fertility variations are compatible with one or another hypothesis. The study controls for origin, destination, and recency of migration, as well as for age, education, and marital status of migrants and stayers. The regional breakdown consists of a cross-classification of rural/urban status with modern/traditional categories based on the level of economic development of the region.