9 resultados para aggregate size classes
em Universidade dos Açores - Portugal
Resumo:
Dissertação de Mestrado, Estudos Integrados dos Oceanos, 15 de Janeiro de 2009, Universidade dos Açores.
Resumo:
Fishing decreases the biomass of target species via reduction in the numbers and/or size of individuals. In natural systems, the strength of biological interactions, including predator-prey dynamics, are often density or size-dependent. Hence, changes in the numbers or size of key taxa may be expected to influence biological interactions but their effects do not need to be identical. Here we compare the effects of biomass reduction in populations of the exploited limpet Patella candei. Biomass removal was experimentally achieved by either removing individuals (density reduction) or by replacing large by small individuals (size reduction), while controlling for total limpet biomass in a laboratory-based experiment. At the experiment’s termination, biomass reduction led to proportional changes in area grazed. However, there was no difference whether this was achieved via changes in density or in size. Furthermore, no discernible effects of treatments were evident on different components of the algal assemblage. A field survey also revealed that P. candei biomass explained a greater proportion in variation in the area free of algae than density alone. Our results suggest that loss of biomass in populations of P. candei has quantitatively and qualitatively similar effects on algal cover regardless of whether it is caused by an equivalent (biomass) reduction in the numbers or size of individuals.
Resumo:
European Cetacean Society Conference Workshop, Galway, Ireland, 25th March 2012.
Resumo:
27th Annual Conference of the European Cetacean Society. Setúbal, Portugal, 8-10 April 2013.
Resumo:
XXI Jornadas de Classificação e Análise de Dados (JOCLAD 2014). 10-12 Abril, 2014, INE, Lisboa, Portugal (Comunicação).
Resumo:
Dissertação de Mestrado em Ciências Económicas e Empresariais.
Resumo:
Mestrado em Educação, especialidade de Administração e Organização Escolar.
Resumo:
The objective of this work is to present elements of the project Student engagement in Schools (SES). The team consists of 10 researchers from six Universities. Student engagement in schools is a multidimensional construct that unites affective, behavioural, and cognitive dimensions of student adaptation in the school and has influence on students’outcomes. The team of researchers conceptualized two major studies, a differential study to analyze the relations between SES and contextual factors, personal factors, student’s outcomes, and a quasi-experimental study to analyze the effects on SES of a specific intervention programmes. In study 1, the sample size is around 600 students (150 6th graders, 150 7th graders, 150 9th graders, and 150 10th graders). We shall focus on years of school transition, with rural and urban populations, on different regions of the country, and on students with different family background. We shall conduct questionnaires with national and international scales. The study 2 will involve students in 7th and 9th grade, from four classes, two of the experimental group and two of the control group. Patterns of verbal communication between a teacher and students can influence the classroom environment and SES. This model of communication would result in more effective student management and more time on-task for learning.
Resumo:
Dissertação de Mestrado, Ciências Económicas e Empresariais, 10 de Dezembro de 2015, Universidade dos Açores.