A strategic model of public–private partnerships in transportation: Effect of taxes and cost structure on investment viability

We formulate a game-theoretic model of a concession agreement between a government and a private party, a concessionaire, who has to engage a set of service providers as part of the operating responsibilities. We use the model to examine the importance of a government's tax policy to induce private investments in transportation infrastructure. Our analysis brings to fore insights that are useful in the design of partnership agreements, such as the importance of early and binding government commitments to ensure stable partnerships, and thus, successful projects. Our analysis shows that these strong commitments are even more critical in situations where the success of the partnership requires participation of additional, self-interested parties, such as specialized service providers. Finally, we consider variations of the model where government preferences are explicitly captured, and where the returns from the fixed cost portion of the concessionaire's investment are exempt from taxes. We show that both variations can lead to outcomes where the concessionaire's tax burden is shifted to the service providers. This flexibility can be critical in the design of partnership agreements for (high-risk or highly specialized transportation) projects where additional incentives may be needed to induce private party participation.     

“The Geography of Maritime Transport–Space as a Perspective in Maritime Research and Development”

Emissions from commercial shipping are currently the subject of intense scrutiny. Among the top fuel-consuming categories of ships and hence air polluters are container vessels. The main reason is their high service speed. Lately, speed reduction has become a very popular operational measure to reduce fuel consumption and can obviously be used to curb emissions. This paper examines such an operational scenario. Since time at sea increases with slow steaming, there is a parallel and strong interest to investigate possible ways to decrease time in port. One way to do so is to reduce port service time. Another possible way to minimize disruption and maximize efficiency is the prompt berthing of vessels upon arrival. To that effect, a related berthing policy is investigated as a measure to reduce waiting time. The objective of reducing emissions along the maritime intermodal container chain is investigated vis-à-vis reduction in operational costs and other service attributes. Some illustrative examples are presented.     

Estimation of air–sea CO2 fluxes in the Bay of Biscay based on empirical relationships and remotely sensed observations

An empirical algorithm has been developed to compute the sea surface CO₂ fugacity (fCO₂^sw) in the Bay of Biscay from remotely sensed sea surface temperature (SST_RS) and chlorophyll a (chl a_RS) retrieved from AVHRR and SeaWiFS sensors, respectively. Underway fCO₂^sw measurements recorded during 2003 were correlated with SST_RS and chl a_RS data yielding a regression error of 0.1 ± 7.5 µatm (mean ± standard deviation). The spatial and temporal variability of air–sea fCO₂ gradient (ΔfCO₂) and air–sea CO₂ flux (FCO₂) was analyzed using remotely sensed images from September 1997 to December 2004. An average FCO₂ of ? 1.9 ± 0.1 mol m^? 2 yr^? 1 characterized the Bay of Biscay as a CO₂ sink that is suffering a significant long-term decrease of 0.08 ± 0.05 mol m^? 2 yr^? 2 in its capacity to store atmospheric CO₂. The main parameter controlling the long-term variability of the CO₂ uptake from the atmosphere was the air–sea CO₂ transfer velocity (57%), followed by the SST_RS (10%) and the chl a_RS (2%).     

Strong bottom–up effects on phytoplankton community caused by a rainfall during spring and summer in Sagami Bay,Japan

To assess the consequences of bottom-up effects on phytoplankton community composition during the rainy season, phytoplankton levels and environmental factors were monitored daily from 12 April to 22 July 2003 in Sagami Bay, Japan. The relevant environmental factors were analyzed using cross-correlation analyses. Based on time-series analysis, low surface salinity conditions lasting 0 or 2 days after heavy rainfalls resulted in significant nutrient loading, such as dissolved inorganic nitrogen (DIN), into the coastal area. Also, Chlorophyll-a (Chl-a) concentration frequently increased 2 and 6 days after rainfall. Based on the high total Chl-a concentration, the time was divided into three periods, from 1 to 11 May (Period A), 26 May to 9 June (Period B) and 30 June to 22 July (Period C). The phytoplankton assemblages during Period A were dominated by two dinoflagellates, Ceratium furca and Ceratium fusus. Prior to these species blooming, the heterotrophic dinoflagellate Noctiluca scintillans was dominant. During Period B, the phytoplankton communities were dominated primarily by the diatoms Rhizosolenia delicatula, Hemiaulus sinensis and Navicula spp. Finally, Cerataulina dentata, Rhizosolenia spp., Lauderia borealis and Neodelphineis pelagica were dominant during Period C. After increases in phytoplankton abundance, available nitrogen (N) and phosphorous (P) were consumed and exhausted, which were considered a potential cause of the shift in the dominant organisms from large diatoms to pico- and nano-plankton in the low Chl-a environment. In particular, silicate (Si) was not a major limiting factor for phytoplankton production, since the Si:DIN and Si:P ratios clearly demonstrated that there were no any potential stoichiometric Si limitations, and almost all silicate concentrations were > 2.0 µM during this study. Our results reveal that nutrient sources supplied by river discharge are a main cue for strong bottom–up effects on algal bloom succession during the early summer season in Sagami Bay.     

DRAG-ALZ-1, a first model of monthly total road demand,accident frequency,severity and victims by category,and of mean speed on highways,Algeria 1970–2007

We construct a first country-wide model of demand for road use and of road safety outcomes for Algeria making use of the DRAG-type framework and of flexible regression estimation methods that make a demonstrable difference to the quality of our results. We imply that the availability of high quality Algerian data could make it worthwhile not only to consider updates of the model with longer data series but also to study variants of the model, notably with disaggregation of freight activities across industrial sectors.