Giuseppe Magnifico - Academia.edu (original) (raw)

Giuseppe Magnifico

Uploads

Papers by Giuseppe Magnifico

Research paper thumbnail of Lévy processes and stochastic von Bertalanffy models of growth, with application to fish population analysis

Journal of Theoretical Biology, 2009

The study of animal growth is a longstanding crucial topic of theoretical biology.

Research paper thumbnail of Progress in modelling herring populations: an individual-based model of growth

Ices Journal of Marine Science, 2009

Stock assessment may gain from taking into account individual variations in growth, because size ... more Stock assessment may gain from taking into account individual variations in growth, because size is a key predictor of survival and reproduction. In trying to understand patterns in empirical observations, a major challenge is to model the changes in the size distribution of a ...

Research paper thumbnail of Evidences on the transient disruption of Sabella spallanzanii (Polychaeta, Sabellidae) fan activity rhythm in laboratory constant darkness

Italian Journal of Zoology, 2008

Circadian and ultradian rhythms were analyzed in Sabella spallanzanii tested in laboratory consta... more Circadian and ultradian rhythms were analyzed in Sabella spallanzanii tested in laboratory constant darkness conditions. A video camera took images per 30 s during a week. The number of times animals opened the fan per 30 min was counted by an observer. Resulting time series were subdivided into 24‐h segments in order to assess the change of the activity rhythm over consecutive days. Periodogram and waveform analyses measured the periodicity and the pattern of fluctuation, at each cycle. Results indicate that animals express a major circadian peak in the first day of test, and this progressively spits into subcomponents from days 2 to 4. At days 5 and 6 the circadian peak is reconstituted. The activity phase of a rhythm (α) and its amplitude of oscillation were also computed per 24‐h segments. The values of different time series were averaged at corresponding 24‐h stages. A significant increment of mean α was observed from days 1 to 4, while conversely the amplitude decreased. From days 5 to day 6, an opposite trend in both variables was observed. These results are descriptive but can be interpreted in the context of models accounting for the generation of ultradian rhythms when controlling oscillators became transiently uncoupled.

Research paper thumbnail of Preliminary evidences of circadian fan activity rhythm in Sabella spallanzanii (Gmelin, 1791) (Polychaeta: Sabellidae

Research paper thumbnail of Lévy processes and stochastic von Bertalanffy models of growth, with application to fish population analysis

Journal of Theoretical Biology, 2009

The study of animal growth is a longstanding crucial topic of theoretical biology.

Research paper thumbnail of Progress in modelling herring populations: an individual-based model of growth

Ices Journal of Marine Science, 2009

Stock assessment may gain from taking into account individual variations in growth, because size ... more Stock assessment may gain from taking into account individual variations in growth, because size is a key predictor of survival and reproduction. In trying to understand patterns in empirical observations, a major challenge is to model the changes in the size distribution of a ...

Research paper thumbnail of Evidences on the transient disruption of Sabella spallanzanii (Polychaeta, Sabellidae) fan activity rhythm in laboratory constant darkness

Italian Journal of Zoology, 2008

Circadian and ultradian rhythms were analyzed in Sabella spallanzanii tested in laboratory consta... more Circadian and ultradian rhythms were analyzed in Sabella spallanzanii tested in laboratory constant darkness conditions. A video camera took images per 30 s during a week. The number of times animals opened the fan per 30 min was counted by an observer. Resulting time series were subdivided into 24‐h segments in order to assess the change of the activity rhythm over consecutive days. Periodogram and waveform analyses measured the periodicity and the pattern of fluctuation, at each cycle. Results indicate that animals express a major circadian peak in the first day of test, and this progressively spits into subcomponents from days 2 to 4. At days 5 and 6 the circadian peak is reconstituted. The activity phase of a rhythm (α) and its amplitude of oscillation were also computed per 24‐h segments. The values of different time series were averaged at corresponding 24‐h stages. A significant increment of mean α was observed from days 1 to 4, while conversely the amplitude decreased. From days 5 to day 6, an opposite trend in both variables was observed. These results are descriptive but can be interpreted in the context of models accounting for the generation of ultradian rhythms when controlling oscillators became transiently uncoupled.

Research paper thumbnail of Preliminary evidences of circadian fan activity rhythm in Sabella spallanzanii (Gmelin, 1791) (Polychaeta: Sabellidae

Log In