Evidence of long-term changes in the distribution of key intertidal species

World Congress of Malacology, Ponta Delgada, July 22-28, 2013.

Habitat differentiation between groups of Risso's dolphins as evidence of coastal nursery areas

26th Annual Conference of the European Cetacean Society, Galway, Ireland 26-28 March 2012.

Climatic patterns and physical controls of chlorophyll-a in the Northeast Atlantic

Tese de Doutoramento, Física, 17 de Dezembro de 2013, Universidade dos Açores.

The gambin model provides a superior fit to species abundance distributions with a single free parameter : evidence, implementation and interpretation

The species abundance distribution (SAD) has been a central focus of community ecology for over fifty years, and is currently the subject of widespread renewed interest. The gambin model has recently been proposed as a model that provides a superior fit to commonly preferred SAD models. It has also been argued that the model's single parameter (α) presents a potentially informative ecological diversity metric, because it summarises the shape of the SAD in a single number. Despite this potential, few empirical tests of the model have been undertaken, perhaps because the necessary methods and software for fitting the model have not existed. Here, we derive a maximum likelihood method to fit the model, and use it to undertake a comprehensive comparative analysis of the fit of the gambin model. The functions and computational code to fit the model are incorporated in a newly developed free-to-download R package (gambin). We test the gambin model using a variety of datasets and compare the fit of the gambin model to fits obtained using the Poisson lognormal, logseries and zero-sum multinomial distributions. We found that gambin almost universally provided a better fit to the data and that the fit was consistent for a variety of sample grain sizes. We demonstrate how α can be used to differentiate intelligibly between community structures of Azorean arthropods sampled in different land use types. We conclude that gambin presents a flexible model capable of fitting a wide variety of observed SAD data, while providing a useful index of SAD form in its single fitted parameter. As such, gambin has wide potential applicability in the study of SADs, and ecology more generally.

The Month-of-the Year Effect nos mercados europeu, americano, australiano e asiático

Dissertação de Mestrado em Gestão/MBA

Cyberbullying and students' engagement in school : a literature review

Bullying is one of today’s biggest problems. Bullying is the intentional repeated aggression directed at a target individual. There is substantial evidence of the negative psychological and health outcomes associated with bullying. It occurs very frequently, especially in adolescence, and action is needed to lessen its causes and alleviate its consequences. Research has shown that behavior problems usually interact with other risk and protection factors, as well as with factors of etiological development. This book discusses the prevalence, psychological impacts and intervention strategies of bullying.