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This paper considers three potentially important modifications to the theory of reasoned action (Fishbein, 1980). It was hypothesized that behavioural norms, or beliefs about the behaviours of others, are important influences above and beyond subjective norms; the effects of attitudes and normative beliefs on intentions and behaviours are interdependent and interactive rather than additive; and the beliefs underlying subjective and behavioural norms are multidimensional rather than unidimensional. These hypotheses were tested in two surveys of smoking intentions and behaviour. The respondents in the first study were primary school children and those in the second study were college students. In both cases behavioural norms and the attitude-normative belief interactions led to significant increases in the prediction of smoking intentions and behaviour. Exploratory factor analyses also suggested that the beliefs underlying subjective norms may be multidimensional rather than unidimensional. These results thus support the hypotheses and suggest that the theory of reasoned action should be modified accordingly.

Detritus from common seagrasses and other marine angiosperms may often be a less important basis for estuarine food webs than previously believed. In NW Gulf of Mexico seagrass meadows, epiphytic algae have high productivities, palatability, and a more important trophic role than common large plants have. Interdisciplinary field experiments show (1) intensive night-time ingestion of epiphytes by various invertebrate "detritivores", (2) very high productivity of epiphytic algae on seagrasses, and (3) assimilation of epiphytes rather than seagrasses, as measured by δC comparisons. These combined data show that many naturally concentrated and potentially competing invertebrates in Gulf of Mexico seagrass meadows feed largely on the algal overgrowth on seagrass blades, even when such algae appear to be sparse. Primary productivity of these epiphytic algae can equal that of the seagrasses, per blade or per unit biomass. Animal δC values tracked epiphytic values rather than seagrass values when comparisons were made over six sites. These measurements reinforce the view that epiphytic algae can be the primary basis of the food web in seagrass meadows.

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This paper seeks to provide a rationale for further researching the everyday events that keep teachers motivated or that discourage them. We put forward the idea that routine Affect Triggering Incidents (ATIs) are an important area for researchers to investigate in terms of how they impact teacher motivation and resilience. Two groups of participants in separate consecutive studies kept weekly diaries of incidents that made them feel good or bad about themselves in their work as teachers (Study 1) and added weekly inventories of their commitment to teaching as well as measures of self-efficacy and self-esteem (Study 2). An analysis of the ATIs in these diaries revealed that student engagement and student achievement are major factors in incidents triggering regular positive feelings while students' behaviour and perceived difficulties around home influences are major factors in regular dissatisfaction. These everyday ATIs are important in the sense that they correlate significantly with measures of commitment to teaching, especially in the case of positive ATIs.

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Introduced populations of the opossum shrimp Mysis relicta take 4 yr to reach reproductive age in Lake Tahoe, California—Nevada and 1—2 yr in Emerald Bay, an isolated (for Mysis) embayment of Lake Tahoe. Reproduction in both populations occurs in the winter and spring. The duration of embryonic stages in the Emerald Bay population based on field population statistics ranged from 50 d for the egg stage to 6 d for the last embryonic stage. The number of eggs per egg—bearing female in Emerald Bay increased significantly with the total length of the female. Over the entire brooding period, the average number of embryos per female decreased from 13.89 eggs per gravid female to 10.33 stage 5 embryos per female. This decline in brood size with age of the brood was not due to size—related mortality, but probably resulted from embryos falling out of the marsupium. A similar decline in brood size with age of the brood was not observed in Lake Tahoe. The average number of eggs per brood in Lake Tahoe was 10.73 which was significantly less than that observed in Emerald Bay. However, there was no difference in the number of stage 5 embryos per brood in both systems. Differences in generation time and total reproductive output in the Lake Tahoe and Emerald Bay populations were most closely related to differences in the overall production and mean depth of the two systems. In addition, these traits and whether reproduction is seasonal or continuous among other mysid populations are strongly correlated with the total production of the environment. These results suggest that differences in M. relicta life history traits among populations may represent a phenotypic and not an evolutionary life history adaptation.

This study hypothesized that closeness of peer group relationships would be a critical factor in determining peer influence on substance use. The hypothesis was examined in a panel study of the effects of peer approval and behaviour on cigarette smoking, drinking and other drug use among Irish adolescents. In support of the closeness hypothesis, the influences relating to peen identified by respondents as 'friends' were better predictors of drug use than were the corresponding k t o n relating tosame-aged peen, while the person identified as the 'best friend' seemed uniquely influential. Furthermore, there were important differences associated with maintenance of drug use as opposed to initiation. both as regards the type of friends and the mediating factors that were important. In particular, it emerged that several good friends were influential (by means of example and approval) in initiation, while the best friend had a critical role in the maintenance of drug use.