The Simon effect and its time courses: an investigation

The objective of the current thesis is to investigate the temporal dynamics (i.e., time courses) of the Simon effect, both from a theoretical and experimental point of view, for a better understanding of whether a) one or more process are responsible for the Simon effect and b) how this/these mechanism/s differently influence performance. In the first theoretical (i.e., “Theoretical Overview”) part, I examined in detail the process and justification for analyzing the temporal dynamics of the Simon effect and the assumptions that underlie interpretation of the results which have been obtained in the existing literature so far. In the second part (“Experimental Investigations”), though, I experimentally investigated several issues which the existing literature left unsolved, in order to get further evidence in favor or in contrast with the mainstream models which are currently used to account for the different Simon effect time courses. Some points about the experiments are worth mentioning: First, all the experiments were conducted in the laboratory, facing participants with stimuli presented on a PC screen and then recording their responses. Both stimuli presentation and response collection was controlled by the E-Prime software. The dependent variables of interest were always behavioral measures of performance, such as velocity and accuracy. Second, the most part of my experiments had been conducted at the Communication Sciences Department (University of Bologna), under Prof. Nicoletti’s supervision. The remaining part, though, had been conducted at the Psychological Sciences Department of Purdue University (West Lafayette, Indiana, USA), where I collaborated for one year as a visiting student with Prof. Proctor and his team. Third, my experimental pool was entirely composed by healthy and young students, since the cognitive functioning of elderly people was not the target of my research.

Effect of different management intensities on natural and human-induced carbon fluxes in a golf course in northern Italy

Turfgrasses are ubiquitous in urban landscape and their role on carbon (C) cycle is increasing important also due to the considerable footprint related to their management practices. It is crucial to understand the mechanisms driving the C assimilation potential of these terrestrial ecosystems Several approaches have been proposed to assess C dynamics: micro-meteorological methods, small-chamber enclosure system (SC), chrono-sequence approach and various models. Natural and human-induced variables influence turfgrasses C fluxes. Species composition, environmental conditions, site characteristics, former land use and agronomic management are the most important factors considered in literature driving C sequestration potential. At the same time different approaches seem to influence C budget estimates. In order to study the effect of different management intensities on turfgrass, we estimated net ecosystem exchange (NEE) through a SC approach in a hole of a golf course in the province of Verona (Italy) for one year. The SC approach presented several advantages but also limits related to the measurement frequency, timing and duration overtime, and to the methodological errors connected to the measuring system. Daily CO2 fluxes changed according to the intensity of maintenance, likely due to different inputs and disturbances affecting biogeochemical cycles, combined also to the different leaf area index (LAI). The annual cumulative NEE decreased with the increase of the intensity of management. NEE was related to the seasonality of turfgrass, following temperatures and physiological activity. Generally on the growing season CO2 fluxes towards atmosphere exceeded C sequestered. The cumulative NEE showed a system near to a steady state for C dynamics. In the final part greenhouse gases (GHGs) emissions due to fossil fuel consumption for turfgrass upkeep were estimated, pinpointing that turfgrass may result a considerable C source. The C potential of trees and shrubs needs to be considered to obtain a complete budget.