Time consistent Pareto solutions in common access resource gameswith asymmetric players

In the analysis of equilibrium policies in a di erential game, if agents have different time preference rates, the cooperative (Pareto optimum) solution obtained by applying the Pontryagin's Maximum Principle becomes time inconsistent. In this work we derive a set of dynamic programming equations (in discrete and continuous time) whose solutions are time consistent equilibrium rules for N-player cooperative di erential games in which agents di er in their instantaneous utility functions and also in their discount rates of time preference. The results are applied to the study of a cake-eating problem describing the management of a common property exhaustible natural resource. The extension of the results to a simple common property renewable natural resource model in in nite horizon is also discussed.

Heterogeneous discounting in consumption-investment problems. Time consistent solutions

[cat] En aquest treball s'analitza un model estocàstic en temps continu en el que l'agent decisor descompta les utilitats instantànies i la funció final amb taxes de preferència temporal constants però diferents. En aquest context es poden modelitzar problemes en els quals, quan el temps s'acosta al moment final, la valoració de la funció final incrementa en comparació amb les utilitats instantànies. Aquest tipus d'asimetria no es pot descriure ni amb un descompte estàndard ni amb un variable. Per tal d'obtenir solucions consistents temporalment es deriva l'equació de programació dinàmica estocàstica, les solucions de la qual són equilibris Markovians. Per a aquest tipus de preferències temporals, s'estudia el model clàssic de consum i inversió (Merton, 1971) per a les funcions d'utilitat del tipus CRRA i CARA, comparant els equilibris Markovians amb les solucions inconsistents temporalment. Finalment es discuteix la introducció del temps final aleatori.

Aggregate monotonic stable single-valued solutions for cooperative games

[cat] En aquest treball caracteritzem les solucions puntuals de jocs cooperatius d'utilitat transferible que compleixen selecció del core i monotonia agregada. També mostrem que aquestes dues propietats són compatibles amb la individualitat racional, la propietat del jugador fals i la propietat de simetria. Finalment, caracteritzem les solucions puntuals que compleixen les cinc propietats a l'hora.

Coalitionally monotonic set-solutions for cooperative TU games

A static comparative study on set-solutions for cooperative TU games is carried out. The analysis focuses on studying the compatibility between two classical and reasonable properties introduced by Young (1985) in the context of single valued solutions, namely core-selection and coalitional monotonicity. As the main result, it is showed that coalitional monotonicity is not only incompatible with the core-selection property but also with the bargaining-selection property. This new impossibility result reinforces the tradeoff between these kinds of interesting and intuitive economic properties. Positive results about compatibility between desirable economic properties are given replacing the core selection requirement by the core-extension property.

Nucleation in supersaturated solutions 3He in 4He at negative pressure.

Depending on the 3He concentration, thermal nucleation in 3-4He supersaturated liquid mixtures at negative pressures may be originated either by bubble or by 3rich drop formation. We have investigated this phenomenon within a density-functional approach, determining the regions in the pressure¿3He-concentration plane where bubbles or drops likely drive the nucleation process. As an illustrative example, we also give the homogeneous nucleation pressure corresponding to 50 and 100 mK temperature.

Classical solutions of the leading-logarithm approximation with non-trivial topology

Exact solutions of the classical equations corresponding to the leading-logarithm approximation are obtained. They are classified by an (integer) topological number.

Annual Report of Iowa Highway Research Board Research and Development Activities FY 2011, December 2011

The Highway Division of the Iowa DOT engages in research and development for two reasons: first, to find workable solutions to the many problems that require more than ordinary, routine investigation; and second, to identify and implement improved engineering and management practices. This report, entitled ―Iowa Highway Research Board Research and Development Activities FY2011‖ is submitted in compliance with Sections 310.36 and 312.3A, Code of Iowa, which direct the submission of a report of the Secondary Road Research Fund and the Street Research Fund, respectively. It is a report of the status of research and development projects in progress on June 30, 2011. It is also a report on projects completed during the fiscal year beginning July 1, 2010 and ending June 30, 2011. Detailed information on each of the research and development projects mentioned in this report is available from the Research and Technology Bureau, Highway Division, Iowa Department of Transportation. All approved reports are also online for viewing at: www.iowadot.gov/operationsresearch/reports.aspx.

2011 Road Use Tax Fund (RUTF) Study A report to the Iowa Legislature, per 2011 Iowa Code Section 307.31

The transportation system is in demand 24/7 and 365 days a year irrespective of neither the weather nor the conditions. Iowa’s transportation system is an integral and essential part of society serving commerce and daily functions of all Iowans across the state. A high quality transportation system serves as the artery for economic activity and, the condition of the infrastructure is a key element for our future growth opportunities. A key component of Iowa’s transportation system is the public roadway system owned and maintained by the state, cities and counties. In order to regularly re-evaluate the conditions of Iowa’s public roadway infrastructure and assess the ability of existing revenues to meet the needs of the system, the Iowa Department of Transportation’s 2006 Road Use Tax Fund (RUTF) report to the legislature included a recommendation that a study be conducted every five years. That recommendation was included in legislation adopted in 2007 and signed into law. The law specifically requires the following (2011 Iowa Code Section 307.31): •“The department shall periodically review the current revenue levels of the road use tax fund and the sufficiency of those revenues for the projected construction and maintenance needs of city, county, and state governments in the future. The department shall submit a written report to the general assembly regarding its findings by December 31 every five years, beginning in 2011. The report may include recommendations concerning funding levels needed to support the future mobility and accessibility for users of Iowa's public road system.” •“The department shall evaluate alternative funding sources for road maintenance and construction and report to the general assembly at least every five years on the advantages and disadvantages and the viability of alternative funding mechanisms.” Consistent with this requirement, the Iowa Department of Transportation (DOT) has prepared this study. Recognizing the importance of actively engaging with the public and transportation stakeholders in any discussion of public roadway conditions and needs, Governor Terry E. Branstad announced on March 8, 2011, the creation of, and appointments to, the Governor’s Transportation 2020 Citizen Advisory Commission (CAC). The CAC was tasked with assisting the Iowa DOT as they assess the condition of Iowa’s roadway system and evaluate current and future funding available to best address system needs. In particular the CAC was directed to gather input from the public and stakeholders regarding the condition of Iowa’s public roadway system, the impact of that system, whether additional funding is needed to maintain/improve the system, and, if so, what funding mechanisms ought to be considered. With this input, the CAC prepared a report and recommendations that were presented to Governor Branstad and the Iowa DOT in November 2011 for use in the development of this study. The CAC’s report is available at www.iowadot.gov/transportation2020/pdfs/CAC%20REPORT%20FINAL%20110211.pdf. The CAC’s report was developed utilizing analysis and information from the Iowa DOT. Therefore, the report forms the basis for this study and the two documents are very similar. Iowa is fortunate to have an extensive public roadway system that provides access to all areas of the state and facilitates the efficient movement of goods and people. However, it is also a tremendous challenge for the state, cities and counties to maintain and improve this system given flattening revenue, lost buying power, changing demands on the system, severe weather, and an aging system. This challenge didn’t appear overnight and for the last decade many studies have been completed to look into the situation and the legislature has taken significant action to begin addressing the situation. In addition, the Iowa DOT and Iowa’s cities and counties have worked jointly and independently to increase efficiency and streamline operations. All of these actions have been successful and resulted in significant changes; however, it is apparent much more needs to be done. A well-maintained, high-quality transportation system reduces transportation costs and provides consistent and reliable service. These are all factors that are critical in the evaluation companies undertake when deciding where to expand or locate new developments. The CAC and Iowa DOT heard from many Iowans that additional investment in Iowa’s roadway system is vital to support existing jobs and continued job creation in the state of Iowa. Beginning June 2011, the CAC met regularly to review material and discuss potential recommendations to address Iowa’s roadway funding challenges. This effort included extensive public outreach with meetings held in seven locations across Iowa and through a Transportation 2020 website hosted by the Iowa DOT (www.iowadot.gov/transportation2020). Over 500 people attended the public meetings held through the months of August and September, with 198 providing verbal or written comment at the meetings or through the website. Comments were received from a wide array of individuals. The public comments demonstrated overwhelming support for increased funding for Iowa’s roads. Through the public input process, several guiding principles were established to guide the development of recommendations. Those guiding principles are: • Additional revenues are restricted for road and bridge improvements only, like 95 percent of the current state road revenue is currently. This includes the fuel tax and registration fees. • State and local governments continue to streamline and become more efficient, both individually and by looking for ways to do things collectively. • User fee concept is preserved, where those who use the roads pay for them, including non¬residents. • Revenue-generating methods equitable across users. • Increase revenue generating mechanisms that are viable now but begin to implement and set the stage for longer-term solutions that bring equity and stability to road funding. • Continue Iowa’s long standing tradition of state roadway financing coming from pay-as-you-go financing. Iowa must not fall into the situation that other states are currently facing where the majority of their new program dollars are utilized to pay the debt service of past bonding. Based on the analysis of Iowa’s public roadway needs and revenue and the extensive work of the Governor’s Transportation 2020 Citizen Advisory Commission, the Iowa DOT has identified specific recommendations. The recommendations follow very closely the recommendations of the CAC (CAC recommendations from their report are repeated in Appendix B). Following is a summary of the recommendations which are fully documented beginning on page 21. 1. Through a combination of efficiency savings and increased revenue, a minimum of $215 million of revenue per year should be generated to meet Iowa’s critical roadway needs. 2. The Code of Iowa should be changed to require the study of the sufficiency of the state’s road funds to meet the road system’s needs every two years instead of every five years to coincide with the biennial legislative budget appropriation schedule. 3.Modify the current registration fee for electric vehicles to be based on weight and value using the same formula that applies to most passenger vehicles. 4.Consistent with existing Code of Iowa requirements, new funding should go to the TIME-21 Fund up to the cap ($225 million) and remaining new funding should be distributed consistent with the Road Use Tax Fund distribution formula. 5.The CAC recommended the Iowa DOT at least annually convene meetings with cities and counties to review the operation, maintenance and improvement of Iowa’s public roadway system to identify ways to jointly increase efficiency. In direct response to this recommendation, Governor Branstad directed the Iowa DOT to begin this effort immediately with a target of identifying $50 million of efficiency savings that can be captured from the over $1 billion of state revenue already provided to the Iowa DOT and Iowa’s cities and counties to administer, maintain and improve Iowa’s public roadway system. This would build upon past joint and individual actions that have reduced administrative costs and resulted in increased funding for improvement of Iowa’s public roadway system. Efficiency actions should be quantified, measured and reported to the public on a regular basis. 6.By June 30, 2012, Iowa DOT should complete a study of vehicles and equipment that use Iowa’s public roadway system but pay no user fees or substantially lower user fees than other vehicles and equipment.

An improved method for measuring soil microbial activity by gas phase flow injection analysis

The rate of carbon dioxide production is commonly used as a measure of microbial activity in the soil. The traditional method of CO2 determination involves trapping CO2 in an alkali solution and then determining CO2 concentration indirectly by titration of the remaining alkali in the solution. This method is still commonly employed in laboratories throughout the world due to its relative simplicity and the fact that it does not require expensive, specific equipment. However, there are several drawbacks: the method is time-consuming, requires large amounts of chemicals and the consistency of results depends on the operator's skills. With this in mind, an improved method was developed to analyze CO2 captured in alkali traps, which is cheap and relatively simple, with a substantially shorter sample handling time and reproducibility equivalent to the traditional titration method. A comparison of the concentration values determined by gas phase flow injection analysis (GPFIA) and titration showed no significant difference (p > 0.05), but GPFIA has the advantage that only a tenth of the sample volume of the titration method is required. The GPFIA system does not require the purchase of new, costly equipment but the device was constructed from items commonly found in laboratories, with suggestions for alternative configurations for other detection units. Furthermore, GPFIA for CO2 analysis can be equally applied to samples obtained from either the headspace of microcosms or from a sampling chamber that allows CO2 to be released from alkali trapping solutions. The optimised GPFIA method was applied to analyse CO2 released from degrading hydrocarbons from a site contaminated by diesel spillage.

Guide to Cement-Based Integrated Pavement Solutions, August 2011

This guide provides a clear, concise, and cohesive presentation of cement-bound materials options for 10 specific engineering pavement applications: new concrete pavements, concrete overlays, previous concrete, precast pavements, roller-compacted concrete, cement-treated base, full-depth reclamation with cement, cement-modified soils, recycled concrete aggregates, and repair and restoration. Each application is presented as a method for meeting specific design and construction objectives that today’s pavement practitioners must accomplish. The benefits, considerations, brief description, and summary of materials, design, and construction requirements, as well as a list of sustainable attributes, are provided for every solution. This guide is intended to be short, simple, and easy to understand. It was designed so that the most up-to-date and relevant information is easily extractable. It is not intended to be used as a design guide for any of the applications identified herein. Recommendations for additional information that can provide such details are given at the end of each solution discussion. The intended audience is practitioners, including engineers and managers who face decisions regarding what materials to specify in the pavement systems they design or manage. The audience also includes city and county engineers, along with the A/E firms that often represent them, and state DOT engineers at all levels who are seeking alternatives in this era of changing markets.