The Case of two Self-Enforcing International Agreements for Environmental Protection with Asymmetric Countries

Non-cooperative game theoretical models of self-enforcing international environmental agreements (IEAs) that employ the cartel stability concept of D’Aspremont et al. (Can J Econ 16:17–25, 1983) frequently assume that countries are identical, and they can sign a single agreement only. We modify the assumption by considering two self-enforcing IEAs and also two types of asymmetric countries. Extending a model of Barrett (Oxford Econ Pap 46:878–894, 1994), we demonstrate that there are similarities between one and two self-enforcing IEAs. But in the case of few countries and high environmental damage we show that two self-enforcing IEA work far better than one self-enforcing IEA in terms of both welfare and environmental quality. Our simulation shows that only if all countries that have fewer benefits and higher cost from pollution abatement must build one coalition, there is hope that two myopic stable coalition can be formed. Moreover, if the cost-benefit functions of pollution abatement impose that the first myopic coalition is formed by countries, which have higher benefits and lower cost from pollution abatement, then two IEA’s worsen abatement and welfare in comparison to one IEA. But, if the first myopic coalition is formed by countries, which have smaller benefits and higher cost from pollution abatement, then two IEA’s improve abatement and welfare in comparison to one IEA.     

Predetermination of potential plastic hinges on reinforced concrete frames using GFRP reinforcement

In the past, glass fiber-reinforced polymer (GFRP)-reinforcement has been successfully applied in reinforced concrete (RC) structures where corrosion resistance, electromagnetic neutrality, or cuttability were required. Previous investigations suggest that the application of GFRP in RC structures could be advantageous in areas with seismic activity due to their high deformability and strength. However, especially the low modulus of elasticity of GFRP limited its wide application as GFRP-reinforced members usually exhibit considerably larger deformations under service loads than comparable steel-reinforced elements. To overcome the aforementioned issues, the combination of steel and GFRP reinforcement in hybrid RC sections has been investigated in the past. Based on this idea, this paper presents a novel concept for the predetermination of potential plastic hinges in RC frames using GFRP reinforcement. To analyze the efficiency of the concept, nonlinear finite element simulations were performed. The results underscore the high efficiency of hybrid steel-GFRP RC sections for predetermining potential plastic hinges on RC frames. The results also indicate that the overall seismic behavior of RC structures could be improved by means of GFRP as both the column base shear force during the seismic activity as well as the plastic deformations after the earthquake were considerably less pronounced than in the steel-reinforced reference structure.     

Max–min fairness in multi-commodity flows

In this paper, we provide a study of Max–Min Fair (MMF) multi-commodity flows and focus on some of their applications to multi-commodity networks. We first present the theoretical background for the problem of MMF and recall its relations with lexicographic optimization as well as a polynomial approach for achieving leximin maximization. We next describe two applications to telecommunication networks, one on routing and the second on load-balancing. We provide some deeper theoretical analysis of MMF multi-commodity flows, show how to solve the lexicographically minimum load network problem for the link load functions most frequently used in telecommunication networks. Some computational results illustrate the behavior of the obtained solutions and the required CPU time for a range of random and well-dimensioned networks.     

A hybrid rerouting scheme

In this work we study a routing scheme combined with an end-to-end rerouting procedure. We focus in particular on a new rerouting strategy called Shared Robust Rerouting (ShRR). This strategy combines three other restoration techniques, namely path diversity, end-to-end rerouting with stub release and global rerouting, in order to achieve cost-effectiveness. Computational results on the bandwidth overhead required by the proposed scheme are provided, as well as a comparison with some conventional restoration schemes.     

X-ray Characterization of Conformational Changes of Human Apo- and Holo-Transferrin

Human serum transferrin (Tf) is a bilobed glycoprotein whose function is to transport iron through receptor-mediated endocytosis. The mechanism for iron release is pH-dependent and involves conformational changes in the protein, thus making it an attractive system for possible biomedical applications. In this contribution, two powerful X-ray techniques, namely Macromolecular X-ray Crystallography (MX) and Small Angle X-ray Scattering (SAXS), were used to study the conformational changes of iron-free (apo) and iron-loaded (holo) transferrin in crystal and solution states, respectively, at three different pH values of physiological relevance. A crystallographic model of glycosylated apo-Tf was obtained at 3.0 Å resolution, which did not resolve further despite many efforts to improve crystal quality. In the solution, apo-Tf remained mostly globular in all the pH conditions tested; however, the co-existence of closed, partially open, and open conformations was observed for holo-Tf, which showed a more elongated and flexible shape overall.     

A Comparative Molecular Dynamics Study of Selected Point Mutations in the Shwachman–Bodian–Diamond Syndrome Protein SBDS

The Shwachman–Diamond Syndrome (SDS) is an autosomal recessive disease whose majority of patients display mutations in a ribosome assembly protein named Shwachman–Bodian–Diamond Syndrome protein (SBDS). A specific therapy for treating this rare disease is missing, due to the lack of knowledge of the molecular mechanisms responsible for its pathogenesis. Starting from the observation that SBDS single-point mutations, localized in different domains of the proteins, are responsible for an SDS phenotype, we carried out the first comparative Molecular Dynamics simulations on three SBDS mutants, namely R19Q, R126T and I212T. The obtained 450-ns long trajectories were compared with those returned by both the open and closed forms of wild type SBDS and strongly indicated that two distinct conformations (open and closed) are both necessary for the proper SBDS function, in full agreement with recent experimental observations. Our study supports the hypothesis that the SBDS function is governed by an allosteric mechanism involving domains I and III and provides new insights into SDS pathogenesis, thus offering a possible starting point for a specific therapeutic option.     

Assigning spare capacities in mesh survivable networks

This paper analyses one key issue of designing reliable networks: assignment of spare capacities in transmission networks. The spare capacities are optimized to facilitate the restoration of single failures. This problem can be formulated as an integer linear program and approximated by its continuous relaxation. This model is based on arc-path formulation especially efficient for dealing with end-to-end rerouting and providing appreciable economies in comparison with local rerouting. The main idea of our method resides in a linear programming decomposition, which permits us to solve problems for medium and large networks. Our approach could be applicable to both STM and ATM-based networks. This method was tested successfully on medium and large DCS-meshed networks and some numerical examples are given to illustrate its performances in terms of CPU time and ratio of optimality. This revised version was published online in June 2006 with corrections to the Cover Date.