Cognitive Control: beyond priming, in aging and across domains

This research project aimed to address many issues related to cognitive control, such as its relationship with repetition priming, its modification in older adults and whether it can be considered a general supra-modality mechanism or rather a set of domain specific ones. The cognitive control mechanism is a top-down modulation involved in conflict resolution processes that is supposed to facilitate the discrimination between signal and noise, or targets and distractors. In the present project cognitive control was investigated through the analysis of congruency (Stroop) and sequential congruency effects with a modification of verbal and spatial Stroop paradigms that exclude the priming confound in two consecutive trials. Results revealed that both congruency and sequential congruency effects are strongly modulated by repetition priming in a verbal Stroop task, whereas a spatial Stroop is only marginally influenced. The comparison of conflict measures and conflict-related ERPs showed that the mechanisms involved in the verbal and spatial tasks are only partially comparable. Both tasks showed congruency effects consistent with previous findings, while sequential congruency effects are apparent in the spatial Stroop performance but are reduced in the verbal task with respect to what is reported in previous studies. In the verbal task we pointed out that cognitive control is likely to detect not the actual conflict level but rather the conflict level change in the present trial with respect to the preceding one and consequently adjust attentional resources, exerting a direct influence on performance. On the other hand, some previous studies suggested that whenever a task presents a high conflict level a proactive inhibition state is activated in order to prevent automatic responses. The results from the spatial Stroop task suggested that the attentional regulatory mechanism for spatial conflict is likely to modulate this proactive inhibition default state on the basis of the preceding trial congruency. In this domain the modulations due to preceding trial congruency and the one due to current trial congruency do not interact in determining ERP components, and this probably generates the strong conflict sequential effects seen in the behavioural performance. Many cognitive aging theories assume a progressive decline in frontal brain areas and many authors reported an age-related deficit in conflict resolution abilities in varied conflict-related tasks, which goes beyond the general slowing showed by older adults. We investigated the effects of normal aging on cognitive control in the verbal and spatial domains, highlighting the fact that the age-related general slowing can account for most of the difference found between younger and older adults, and that the verbal congruency effect is the only measure that suffers from a specific decline. Moreover intelligence and cognitive reserve (CR) seemed to partially account for the inter-individual variability in conflict resolution performance, especially in cognitive aging. Finally, the hypothesis of a general, supra-domain cognitive control mechanism is discussed, since evidence reported in the present project rather supports the existence of more domain specific sub-mechanisms of cognitive control

Transient polarization dynamics in a CO2_2 laser

We study experimentally and theoretically the polarization alternation during the switch-on transient of a quasi-isotropic CO$_2$ laser emitting on the fundamental mode. The observed transient dynamics is well reproduced by means of a model which provides a quantitative discrimination between the intrinsic asymmetry due to the kinetic coupling of molecules with different angular momenta, and the extrinsic anisotropies, due to a tilted intracavity window. Furthermore, the experiment provides a numerical assignment for the decay rate of the coherence term for a CO$_2$ laser.Comment: 14 pages, 6 figures, submitted to Opt. Com

I BUY-SELL AGREEMENTS NEL TRASFERIMENTO DELLE PARTECIPAZIONI SOCIALI -Realtà statunitense e italiana a confronto-

I buy-sell agreements sono accordi utilizzati negli Stati Uniti per programmare il futuro trasferimento della partecipazione di un socio al verificarsi di determinati eventi che lo coinvolgono. Essi sono incentrati soprattutto sugli aspetti di valutazione della quota trasferita. Si va ad analizzare il contesto italiano in cui possono inserirsi: sia per quanto riguarda gli aspetti legati alla valutazione, in termini di logiche, configurazione di capitale e metodologie applicabili; che per quanto concerne l’ambito giuridico, ricollegandoli ai patti parasociali e in modo particolare ai patti di riscatto