Transportation theory and planning

The aim of this research is to analyze the transport system and its subcomponents in order to highlight which are the design tools for physical and/or organizational projects related to transport supply systems. A characteristic of the transport systems is that the change of their structures can recoil on several entities, groups of entities, which constitute the community. The construction of a new infrastructure can modify both the transport service characteristic for all the user of the entire network; for example, the construction of a transportation infrastructure can change not only the transport service characteristics for the users of the entire network in which it is part of, but also it produces economical, social, and environmental effects. Therefore, the interventions or the improvements choices must be performed using a rational decision making approach. This approach requires that these choices are taken through the quantitative evaluation of the different effects caused by the different intervention plans. This approach becomes even more necessary when the decisions are taken in behalf of the community. Then, in order to understand how to develop a planning process in Transportation I will firstly analyze the transport system and the mathematical models used to describe it: these models provide us significant indicators which can be used to evaluate the effects of possible interventions. In conclusion, I will move on the topics related to the transport planning, analyzing the planning process, and the variables that have to be considered to perform a feasibility analysis or to compare different alternatives. In conclusion I will perform a preliminary analysis of a new transit system which is planned to be developed in New York City.

Response of Microcystis aeruginosa PCC 7806 to different CO2 concentrations

Future climatic change scenarios predict rising of the atmospheric CO2 levels which could favor the proliferation of some harmful bloom-forming cyanobacteria as Microcystis aeruginosa. In the present study, the response of M. aeruginosa strain PCC 7806 to two different partial pressure of CO2 was tested. Sandrini et al. (2013) recently found that several, but not all, M. aeruginosa strains lack the SbtA or BicA HCO3- uptake system genes; the contribution of different Ci transporters to photosynthesis and the difference between low and high affinity activated Ci uptake state were investigated. M. aeruginosa PCC 7806 was cultured in four chemostats containing modified BG11 medium with 10 mM NaNO3 and no presence of NaCl, NaHCO3, Na2CO3 and additional buffers. A wide variety of analysis on samples collected from continuous cultures – such as A750, medium composition, cellular composition, cell counting, mini-PAM, measurements with the O2 optode, Aminco, 77K fluorescence emission spectra – was carried out. Data analysis results showed that the increased CO2 concentration has a big effect on M. aeruginosa PCC 7806. Experiments were performed using the Oxy-4 O2 optode apparatus in order to measure the photosynthetic O2 evolution of samples taken from both batch and chemostat cultures. At low bicarbonate concentration, an evident inhibition of Na+-dependent HCO3- transporter BicA by LiCl at 25 mM was observed. The consequent addition of 25 mM NaCl was able to counteract the Li+ effect at pH 8.0 but not at pH 10.0. In the latter case, only the addition of a higher amount of HCO3- led to photosynthetic O2 evolution suggesting the important role of the BicA transporter. However, further studies are needed to better explain the results obtained as high pH levels might have an influence on the transport systems, altering the mechanism of pH regulation and the functioning of Na+/H+ antiporter systems.

Micro-simulation models at neighbourhood scale: the interplay of agents, buildings, activities and transport.

Urban systems consist of several interlinked sub-systems - social, economic, institutional and environmental – each representing a complex system of its own and affecting all the others at various structural and functional levels. An urban system is represented by a number of “human” agents, such as individuals and households, and “non-human” agents, such as buildings, establishments, transports, vehicles and infrastructures. These two categories of agents interact among them and simultaneously produce impact on the system they interact with. Try to understand the type of interactions, their spatial and temporal localisation to allow a very detailed simulation trough models, turn out to be a great effort and is the topic this research deals with. An analysis of urban system complexity is here presented and a state of the art review about the field of urban models is provided. Finally, six international models - MATSim, MobiSim, ANTONIN, TRANSIMS, UrbanSim, ILUTE - are illustrated and then compared.