Concessions of Infrastructure in Latin America: Government-led Renegotiation

This paper completes Guasch, Laffont and Straub (2003), extending the analysis to the case of government-led renegotiations. We first extend the theoretical framework to a multiple-period context in which both Pareto improving and rent shifting renegotiations at the initiative of the government can occur. We then perform an empirical analysis based on the same sample of 307 water and transport projects in 5 Latin American countries between 1989 and 2000. While some of the main insights, for example concerning the importance of having a regulator in place when awarding concessions and the fragility of price cap regulatory schemes, are unchanged, there are also significant differences, in particular with respect to the effect of investment and financing, as well as the corruption variables. We also provide additional evidence showing that a good regulatory framework is especially important in contexts with weak governance and political opportunism.

Renegotiation of concession contracts in Latin America

The authors construct a regulation model in which renegotiation occurs due to the imperfect enforcement of concession contracts. This enables the authors to provide theoretical predictions for the impact on the probability of renegotiation of a concession, regulatory institutions, institutional features, economic shocks, and the characteristics of the concession contracts. Then they use a data set of nearly 1,000 concessions awarded in Latin America and the Caribbean countries from 1989 to 2000 covering the sectors of telecommunications, energy, transport, and water to test these predictions. Finally, the authors derive some policy implications of their theoretical and empirical work.Environmental Economics&Policies,Health Economics&Finance,Administrative&Regulatory Law,Decentralization,Labor Policies,Health Economics&Finance,Environmental Economics&Policies,National Governance,Administrative&Regulatory Law,Public Sector Economics&Finance

Renegotiation of Concession Contracts in Latin America.

We construct a regulation model in which renegotiation occurs due to the imperfect enforcement of concession contracts. This enables us to provide theoretical predictions for the impact, on the probability of renegotiation of a concession, of regulatory institutions, institutional features, economic shocks and of the characteristics of the concession contracts themselves. Then we use a data set of nearly 1000 concessions awarded in Latin America and the Caribbean countries from 1989 to 2000, covering the sectors of telecommunications, energy, transport and water, to test these predictions. Finally, we derive some policy implications of our theoretical and empirical work.Renegotiation, Concession contracts, Regulation, LDCs.

Anatomy of ε′/ε\varepsilon'/\varepsilon beyond the Standard Model

We present for the first time a model-independent anatomy of the ratio $\varepsilon'/\varepsilon$ in the context of the $\Delta S = 1$ effective theory with operators invariant under QCD and QED and in the context of the Standard Model Effective Field Theory (SMEFT) with the operators invariant under the full SM gauge group. Our goal is to identify the new physics scenarios that are probed by this ratio and which could help to explain a possible deviation from the SM that is hinted by the data. To this end we derive a master formula for $\varepsilon'/\varepsilon$, which can be applied to any theory beyond the Standard Model (BSM) in which the Wilson coefficients of all contributing operators have been calculated at the electroweak scale. The relevant hadronic matrix elements of BSM operators are from the Dual QCD approach and the SM ones from lattice QCD. Within SMEFT, the constraints from $K^0$ and $D^0$ mixing as well as electric dipole moments limit significantly potential new physics contributions to $\varepsilon'/\varepsilon$. Correlations of $\varepsilon'/\varepsilon$ with $K\to\pi\nu\bar\nu$ decays are briefly discussed. Building on our EFT analysis and the model-independent constraints, we discuss implications of a possible deviation from the SM in $\varepsilon'/\varepsilon$ for model building, highlighting the role of the new scalar and tensor matrix elements in models with scalar mediators.Comment: 47 pages, 4 figures. v3: signs in tables 6-10 corrected, numerical results and conclusions unchange

Radiation Fog Chemical Composition and Its Temporal Trend Over an Eight Year Period

Radiation fog samples have been collected at a rural site in Central Pennsylvania from 2007 through 2015 in order to document chemical composition, assess concentration changes over time, and to provide insight into emission sources that influence the region. The collection of samples over multiple years makes this one of the few long duration radiation fog studies that have been completed. During the course of the campaign, 146 samples were obtained and analyzed for pH, major inorganic ions, low molecular weight organic acids, total organic carbon (TOC) and total nitrogen (TN). Ammonium (median concentration = 209 μN), sulfate (69 μN), calcium (51 μN), and nitrate (31 μN) were the most abundant inorganic ions, although these were present at much lower concentrations than for radiation fog studies conducted in other locations. Organic acids, of which formate (20 μM) and acetate (21 μM) were the most abundant, were closer in magnitude to measurements made during previous studies. Organic acids accounted for 15% of TOC, which had a median concentration of 6.6 mgC l-1. The median concentration of TN was 3.6 mgN l-1, 18% of which was determined to be organic nitrogen. Statistically significant decreasing trends from 2007 to 2015 were noted for sulfate, ammonium, chloride, and nitrate. For the same period, an increase in pH was observed. Seasonal trends were identified for a number of species as well. The partitioning of ammonia between the gas and aqueous phases was also investigated and found to deviate significantly from equilibrium

Probing the Mechanisms of Fibril Formation Using Lattice Models

Using exhaustive Monte Carlo simulations we study the kinetics and mechanism of fibril formation using lattice models as a function of temperature and the number of chains. While these models are, at best, caricatures of peptides, we show that a number of generic features thought to govern fibril assembly are present in the toy model. The monomer, which contains eight beads made from three letters (hydrophobic, polar, and charged), adopts a compact conformation in the native state. The kinetics of fibril assembly occurs in three distinct stages. In each stage there is a cascade of events that transforms the monomers and oligomers to ordered structures. In the first "burst" stage highly mobile oligomers of varying sizes form. The conversion to the aggregation-prone conformation occurs within the oligomers during the second stage. As time progresses, a dominant cluster emerges that contains a majority of the chains. In the final stage, the aggregation-prone conformation particles serve as a template onto which smaller oligomers or monomers can dock and undergo conversion to fibril structures. The overall time for growth in the latter stages is well described by the Lifshitz-Slyazov growth kinetics for crystallization from super-saturated solutions.Comment: 27 pages, 6 figure