The handshake : why do governments and firms sign private sector participation deals ? Evidence from the water and sanitation sector in developing countries

This paper uses a new dataset,"WATSAN,"of private sector participation(PSP) projects for water and sanitation in developing countries to examine the determinants of the number of projects signed for each country between 1990 and 2004. The new dataset improves on existing sources, in particular in its coverage of projects with local investors, and provides adequate data for cross-country regression analysis. The authors use a negative binomial regression model to investigate the factors influencing the number of PSP projects in a sample of 60 developing countries with 460 PSP projects. The regression results provide support for the hypotheses that PSP is greater in larger markets where the ability to pay is higher and where governments are fiscally constrained. The authors test several indicators of institutional quality and find that these are generally significant in determining the number of projects signed for each country. Measures of the protection of property rights and the quality of the bureaucracy emerge as the most important institutions that encourage PSP. Rule of law and the control of corruption are significant, albeit at a lower level, while the quality of contract law and political stability are not robustly significant.Private Participation in Infrastructure,Town Water Supply and Sanitation,Investment and Investment Climate,Infrastructure Regulation,Water Supply and Sanitation Governance and Institutions

Some variance reduction methods for numerical stochastic homogenization

We overview a series of recent works devoted to variance reduction techniques for numerical stochastic homogenization. Numerical homogenization requires solving a set of problems at the micro scale, the so-called corrector problems. In a random environment, these problems are stochastic and therefore need to be repeatedly solved, for several configurations of the medium considered. An empirical average over all configurations is then performed using the Monte-Carlo approach, so as to approximate the effective coefficients necessary to determine the macroscopic behavior. Variance severely affects the accuracy and the cost of such computations. Variance reduction approaches, borrowed from other contexts of the engineering sciences, can be useful. Some of these variance reduction techniques are presented, studied and tested here

EX ANTE CONSTRUCTION COSTS IN THE EUROPEAN ROAD SECTOR: A COMPARISON OF PUBLIC-PRIVATE PARTNERSHIPS AND TRADITIONAL PUBLIC PROCUREMENT

Theoretical literature suggests a variety of reasons why a public-private partnership (PPP)should exhibit higher costs of construction than traditionally procured public infrastructure projects. The bundling of construction and operation contracts in a PPP give the private partner greater incentives to make investments in the construction phase to lower subsequent operation and maintenance costs. Also, the transfer of the construction risk to the private partner should be explicitly priced in a PPP. We use data on ex ante construction costs of road projects in Europe to test the existence and the magnitude of any such difference between PPPs and traditional procurement. We estimate the ex ante cost of a PPP road to be, on average, 24% more expensive than a traditionally procured road, all other things equal. This estimate corresponds by and large to reported ex post cost overruns in traditionally procured public roads. To the extent that the two measures are representative, this suggests that the largest part of the ex ante construction cost difference originates from the transfer of construction risk. This, in turn, implies that other possible sources of higher PPP construction costs, including bundling, seem to be of second-order importance in the road sector. The analysis does not allow drawing normative conclusions about the desirability of PPP as a procurement method as it focuses only on one cost component in isolation, without being able to quantify its impact on life-cycle costs and benefits.Construction costs; Road sector; public-private partnership; public procurement; infrastructure projects; Europe

PUBLIC-PRIVATE PARTNERSHIPS IN EUROPE: AN UPDATE

This paper offers an updated description of the macroeconomic and sectoral significance of PPPs in Europe, without assessing PPPs from a normative perspective. It shows that, over the past fifteen years, more than one thousand PPP contracts have been signed in the EU, representing a capital value of almost 200 billion euro. While PPPs have in recent years become increasingly popular in a growing number of European countries, they are of macroeconomic and systemic significance only in the UK, Portugal, and Spain. In all other European countries, the importance of investment through PPPs remains small in comparison to traditional public procurement of investment projects. However, PPP procurement is used extensively for major projects and this is spreading out from transport into other sectors.public-private partnership; Europe

IZI: Inferring the gas phase metallicity (Z) and ionization parameter (q) of ionized nebulae using bayesian statistics

We present a new method for inferring the metallicity (Z) and ionization parameter (q) of H ii regions and star-forming galaxies using strong nebular emission lines (SELs). We use Bayesian inference to derive the joint and marginalized posterior probability density functions for Z and q given a set of observed line fluxes and an input photoionization model. Our approach allows the use of arbitrary sets of SELs and the inclusion of flux upper limits. The method provides a self-consistent way of determining the physical conditions of ionized nebulae that is not tied to the arbitrary choice of a particular SEL diagnostic and uses all the available information. Unlike theoretically calibrated SEL diagnostics, the method is flexible and not tied to a particular photoionization model. We describe our algorithm, validate it against other methods, and present a tool that implements it called IZI. Using a sample of nearby extragalactic H ii regions, we assess the performance of commonly used SEL abundance diagnostics. We also use a sample of 22 local H ii regions having both direct and recombination line (RL) oxygen abundance measurements in the literature to study discrepancies in the abundance scale between different methods. We find that oxygen abundances derived through Bayesian inference using currently available photoionization models in the literature can be in good (∼30%) agreement with RL abundances, although some models perform significantly better than others. We also confirm that abundances measured using the direct method are typically ∼0.2 dex lower than both RL and photoionization-model-based abundances

Direct structural identification of carbenium ions and investigation of host-guest interaction in the methanol to olefins reaction obtained by multinuclear NMR correlations

Probing and determining the intermediates formed during catalytic reactions in heterogeneous catalysis are strong challenges. Using C-13 labelling and two dimensional C-13-C-13 through-bond NMR correlations, we directly reveal the structures of a range of carbenium ion species formed during the conversion of methanol to olefins on acidic H-ZSM-5 zeolite by mapping the carbon-carbon bond connectivities. Additionally, we use C-13-Al-27 and Si-29-C-13 through-space NMR experiments to probe the interactions between the confined carbon species (including carbenium ions) and the framework of the zeolite, which quantitatively provide an estimate for the carbon-aluminium and carbon-silicon distances, respectively

Influence of Functionalization of Nanocontainers on Self-Healing Anticorrosive Coatings

Feedback coating based on pH-induced release of inhibitor from organosilyl-functionalized containers is considered as a compelling candidate to achieve smart self-healing corrosion protection. Four key factors that determine the overall coating performance include 1) the uptake and release capacity of containers, 2) prevention of the premature leakage, 3) compatibility of containers in coating matrix and 4) cost and procedure simplicity consideration. The critical influence introduced by organosilyl-functionalization of containers is systematically demonstrated by investigating MCM-41 silica nanoparticles modified with ethylenediamine (en), en-4-oxobutanoic acid salt (en-COO-) and en-triacetate (en-(COO-)3) with higher and lower organic contents. The properties of the modified silica nanoparticles as containers were mainly characterized by solid-state 13C nuclear magnetic resonance, scanning and transmission electron microscopy, N2 sorption, thermogravimetric analysis, small-angle X-ray scattering, dynamic light scattering and UV-vis spectroscopy. Finally, the self-healing ability and anticorrosive performances of hybrid coatings were examined through scanning vibrating electrode technique (SVET) and electrochemical impedance spectroscopy (EIS). en-(COO-)3- type functionalization with content of only 0.23 mmol/g was found to perform the best as a candidate for establishing pH-induced release system. It is because the resulting capped and loaded (C-L) functionalized silica nanocontainers (FSNs) exhibit a high loading (26 wt%) and release capacity (80%) for inhibitor, prevention of premature leakage (less than 2%), good dispersibility in coating matrix and cost effectiveness