Phylogenetic analysis reveals an ancient gene duplication as the origin of the MdtABC efflux pump.

The efflux pumps from the Resistance-Nodulation-Division family, RND, are main contributors to intrinsic antibiotic resistance in Gram-negative bacteria. Among this family, the MdtABC pump is unusual by having two inner membrane components. The two components, MdtB and MdtC are homologs, therefore it is evident that the two components arose by gene duplication. In this paper, we describe the results obtained from a phylogenetic analysis of the MdtBC pumps in the context of other RNDs. We show that the individual inner membrane components (MdtB and MdtC) are conserved throughout the Proteobacterial species and that their existence is a result of a single gene duplication. We argue that this gene duplication was an ancient event which occurred before the split of Proteobacteria into Alpha-, Beta- and Gamma- classes. Moreover, we find that the MdtABC pumps and the MexMN pump from Pseudomonas aeruginosa share a close common ancestor, suggesting the MexMN pump arose by another gene duplication event of the original Mdt ancestor. Taken together, these results shed light on the evolution of the RND efflux pumps and demonstrate the ancient origin of the Mdt pumps and suggest that the core bacterial efflux pump repertoires have been generally stable throughout the course of evolution

Enforcing ‘Self-Enforcing’ International Environmental Agreements

Theoretical analyses of international environmental agreements (IEAs) have typically employed the concept of self-enforcing agreements to predict the number of parties to such an agreement. The term self-enforcing, however, is a bit misleading. The concept refers to the stability of cooperative agreements, not to enforcing these agreements once they are in place. Most analyses of IEAs simply ignore the issue of enforcing compliance by parties to the terms of an agreement. In this paper we analyze an IEA game in which parties to an agreement finance an independent enforcement body with the power to monitor the parties’ compliance to the terms of the IEA and impose penalties in cases of noncompliance. This approach is broadly consistent with the enforcement mechanism of the Kyoto Protocol under the Marrakesh Accords. We find that costly enforcement limits the circumstances under which international cooperation to protect the environment is worthwhile, but when IEAs do form they will involve greater participation than IEAs that do not require costly enforcement. Consequently, costly enforcement of IEAs is associated with higher international environmental quality. Moreover, under certain conditions, aggregate welfare is higher when IEAs require costly enforcement. These conclusions are accentuated when monitoring for compliance to IEAs is inaccurate.International environmental agreements, self-enforcing agreements, compliance, enforcement

Costly Enforcement of Voluntary Environmental Agreements with Industries

Although the theoretical literature on the performance of voluntary approaches to environmental protection has progressed quite far in the last decade, no one has rigorously addressed the obvious point that even voluntary emissions control policies must be enforced. This paper examines the consequences of the need for costly enforcement of voluntary environmental agreements with industries on the ability of these agreements to meet regulatory objectives, the levels of industry participation with these agreements, and the relative efficiency of voluntary and regulatory approaches. We find that enforcement costs that are borne by the members of a voluntary emissions control agreement limit the circumstances under which an agreement can form in place of an emissions tax. However, if an agreement does form, member-financed enforcement induces greater participation than if compliance with the agreement could be enforced without cost to its members. Moreover, a voluntary emission control agreement with an industry can be a more efficient way to achieve an environmental quality objective than an emission tax, but only if: (1) the members of an agreement bear the costs of enforcing compliance with the agreement; (2) there exists member-financed agreements that reach the government’s environmental quality target while leaving the members of the agreement at least as well off as they would be under an emissions tax, and (3) the enforcer of the agreement has a significantly better monitoring technology or a higher sanction available to it than the government.Voluntary agreements, self-enforcing agreements, emissions tax, enforcement

The Endogenous Formation of Coalitions to Provide Public Goods: Theory and Experimental Evidence

This paper examines the endogenous formation of coalitions that provide public goods in which players implement a minimum participation requirement before deciding whether to join. We demonstrate theoretically that payoff-maximizing players will vote to implement efficient participation requirements and these coalitions will form. However, we also demonstrate that if some players are averse to inequality they can cause inefficient outcomes. Inequality-averse players can limit free riding by implementing larger than efficient coalitions or by blocking efficient coalitions from forming. We test the theory with experimental methods and observe individual behavior and coalition formation consistent with a model of inequality-averse players. Key Words:

The Effects of ITQ Management on Fishermen’s Welfare When the Processing Sector is Imperfectly Competitive

In this paper we use a general model of imperfect competition to predict welfare changes within an open-access fishery transitioning to individual transferable quota (ITQ) management. Although related research has explored the effects of market power in the harvesting sector on ITQ performance, none have considered the implications of an imperfectly competitive processing sector. This study addresses this question specifically in the context of the Atlantic herring fishery, although its implications are relevant to all fisheries with similar industry structure. Our results show that ITQs could have a negative impact on fishermen’s welfare when processors have market power and the cap on aggregate harvest is binding or becomes binding with the implementation of ITQs.ITQ, imperfect competition, welfare analysis, fisheries

The Problem of Maintaining Compliance within Stable Coalitions: Experimental Evidence

This study examines the performance of stable cooperative coalitions that form to provide a public good when coalition members have the opportunity to not comply with their commitments. A stable coalition is one in which no member wishes to leave and no non-member wishes to join. To counteract the incentive to violate their commitments, coalition members fund a third-party enforcer. This leads to the theoretical conclusion that stable coalitions are larger (and provide more of a public good) when their members must finance enforcement relative to when compliance is ensured without the need for costly enforcement. However, our experiments reveal that giving coalition members the opportunity to violate their commitments while requiring them to finance enforcement to maintain compliance reduces the overall provision of the public good. The decrease in the provision of the public good is attributed to an increase in the participation threshold for a theoretically stable coalition to form and to significant levels of noncompliance. When we abandon the strict stability conditions and require all subjects to join a coalition for it to form, the average provision of the public good increases significantly. Key Words: stable coalitions, self-enforcing agreements, compliance, enforcement, public goods

Caring for Transgender patients in the ICU: Current insights for equitable care

There is ever more focus on issues surrounding Transgender/Trans people and their healthcare needs, and while there is a dearth of evidence related to Intensive Care, this paper aims to address considerations for ICU nurses when caring for Trans patients. These include both the overall approach to person-centred care for Trans patients as well as the physiological considerations that necessitate nursing interventions