Panic-based overfishing in transboundary fisheries

This paper analyses sustainability of bilateral harvesting agreements in transboundary fisheries. Harvesting countries obtain public and private assessments regarding their stock of fish, and the stock experiences ecological changes. In addition to biological uncertainty, countries may face strategic uncertainty. A country that receives negative assessments about the current level of fish stock, may become ‘pessimistic’ about the assessment of the other coastal state, and this can ignite ‘panic-based’ overfishing. The paper examines the likelihood of overfishing and suggests a unique prediction about the possibility of abiding by bilateral fishing agreements. Conditions under which the outcome of the asymmetric-information model reduces to the symmetric-information game are discussed, and optimal policy instruments for intergovernmental management of the stock are offered

Panic-based overfishing in transboundary fisheries

This paper analyses sustainability of bilateral harvesting agreements in transboundary fisheries. Harvesting countries obtain public and private assessments regarding their stock of fish, and the stock experiences ecological changes. In addition to biological uncertainty, countries may face strategic uncertainty. A country that receives negative assessments about the current level of fish stock, may become ‘pessimistic’ about the assessment of the other coastal state, and this can ignite ‘panic-based’ overfishing. The paper examines the likelihood of overfishing and suggests a unique prediction about the possibility of abiding by bilateral fishing agreements. Conditions under which the outcome of the asymmetric-information model reduces to the symmetric-information game are discussed, and optimal policy instruments for intergovernmental management of the stock are offered

Information design in coalition formation games

I examine a setting, where an information sender conducts research into a payoff-relevant state variable, and releases information to agents, who consider joining a coalition. The agents’ actions can cause harm by contributing to a public bad. The sender, who has commitment power, by designing an information mechanism (a set of signals and a probability distribution over them), maximises his payoff, which depends on the action taken by the agents, and the state variable. I show that the coalition size, as a function of beliefs of agents, is an endogenous variable, induced by the information sender. The optimal information mechanism from the general set of public information mechanisms, in coalition formation games is derived. I also apply the results to International Environmental Agreements (IEAs), where a central authority, as an information sender, attempts to reduce the global level of greenhouse gases (GHG) by communication of information on social cost of GHG

Information disclosure and dynamic climate agreements: shall the IPCC reveal it all?

This paper examines the role of public information communication in dynamic self-enforcing climate agreements. We consider a framework with implicit contracts but also a dynamic coalition formation context. In a stochastic game, where the social cost of Greenhouse Gasses (GHG) is an unknown random variable, an information sender, such as the Intergovernmental Panel on Climate Change (IPCC), controls the release of verifiable information about the unknown state variable to the countries. The equilibrium communication strategy of the IPCC takes a threshold form, above which the IPCC reveals all the information available, even if it hurts the prospect of approaching the socially optimum level of emissions. The case where the IPCC remains silent, below the threshold, vanishes as the sender gets perfectly informed about the underlying social cost

Post-Earthquake Evaluation and Emergency Repair of Damaged RC Bridge Columns Using CFRP Materials

Report No. CCEER-10-05The main objective of the study was to develop a rapid and effective repair method using carbon fiber reinforced polymer (CFRP) materials for earthquake-damaged reinforced concrete bridge columns. This study consisted of three main phases. In the first phase, a data base of 33 test columns was developed and analyzed and five distinct apparent seismic damage states were defined. The damage states were correlated to measured seismic response parameters in terms of drift, frequency, strains, and yield and ultimate displacements. Fragility curves were developed and applied for two case studies in performance-based design (PBD) and performance-based assessment (PBA) of bridge columns. Comprehensive experimental and analytical studies were conducted in the second phase of the study. Two standard single columns, one standard two-column bent, and two substandard columns were tested on a shake table, repaired using CFRP fabrics, and retested on the shake table to evaluate the proposed repair procedure. The measured data were extensively analyzed to investigate the performance of the repaired columns compared to the original column responses. It was concluded that the strength and ductility of the standard columns were successfully restored and those of sub-standard columns were upgraded to the current seismic standards after the repair. However, the stiffness was not restored due to material degradation during the original column tests. Even though the repair process was done rapidly and was treated as "emergency" repair with implication that it was a temporary measure, it can be treated as a permanent repair as long as the stiffness of repaired columns is sufficient for non-seismic loading. In the analytical studies, extensive static and dynamic nonlinear analyses were performed on the column models and a simple analytical method was developed for the repaired columns to account for stiffness degradation. Based on the results from the experimental and analytical studies, repair design recommendations were developed in the third phase to aid bridge engineers in quickly designing the number of layers of CFRP layers based on the apparent damage and basic information about the column fixity, size, and reinforcement

An analytical study on electronic transport of typical nanotubes with square structure network

In this study, we investigated the electronic conductance of two typical single-wall nanotubes with square lattice by using Green’s function method in tight-binding approximation. Then the effect of various factors such as presence of symmetrical bond defects, the distance between two defects and the nanotube hopping energies was studied on the system electronic conductance. The square and rhombic nanotubes showed metallic and insulator/semiconductor behaviors, respectively

Self-enforcing climate coalitions for farsighted countries: integrated analysis of heterogeneous countries

This paper studies the formation of international climate coalitions by heterogeneous countries. Countries rationally predict the consequences of their membership decisions in climate negotiations. We offer an approach to characterise the equilibrium number of coalitions and their number of signatories independent of their heterogeneity, and we suggest a tractable algorithm to fully characterise the equilibrium. In a dynamic game analysis of a general equilibrium model of the economy integrated with climate dynamics, a grand climate coalition or multiple climate coalitions may form in equilibrium, but if the policymakers are patient, the number of signatories in all climate treaties is a Tribonacci number. Our results are robust to the possibility of renegotiation and investment in green technologies besides fossil fuels

Synthesis and In Vitro Cytotoxic Activity of 2-Amino-7-(dimethylamino)-4-[(trifluoromethyl)phenyl]-4H-chromenes

Three 2-amino-4-(trifluoromethylphenyl)-3-cyano-7-(dimethylamino) -4H-chromene derivatives were synthesized and their cytotoxic activities were determined against six human tumor cell lines using MTT assay. Condensation of 3-(dimethylamino)phenol, trifluoromethybenzaldehydes and malonitrile in ethanol containing piperidine afforded corresponding chromenes (4a-c). The structure of the synthesized compound was confirmed by 1H NMR, IR and Mass spectral data. Among compounds tested, 3-trifluoromethyl analogue (3b) was the most active against all human tumor cell lines (IC50=12-45 nM)

Discordance in categorization of acute-on-chronic liver failure in the United Network for Organ Sharing database

Studies regarding acute-on-chronic liver failure (ACLF) among liver transplant (LT) candidates from the United Network for Organ Sharing (UNOS) database are being used to inform LT policy changes worldwide. We assessed the validity of identifying ACLF in UNOS. We performed stratified random sampling among 3 US LT centers between 2013-2019 to obtain a representative patient sample across ACLF grades. We compared the concordance of ACLF classification by UNOS vs. blinded manual chart review, according to EASL-CLIF. Among 481 sampled LT registrants, 250 (52%) had no ACLF, 75 (16%) had ACLF grade 1, 79 (16%) had ACLF grade 2, and 77 (16%) had ACLF grade 3 per UNOS categorization. Concordance of ACLF grade by UNOS vs. chart review was: 72%, 64%, 56%, and 64% for no ACLF, grade 1, grade 2, and grade 3, respectively, with an overall Cohen’s kappa coefficient of 0.48 (95% CI 0.42–0.54). Absence of acute decompensation was the most common reason for overestimation, and discordant brain and respiratory failure categorization were the most common reasons for underestimation of ACLF by UNOS. In this retrospective multi-center study, ACLF categorization by UNOS showed weak agreement with manual chart review. These findings are informative for ongoing allocation policy discussions, highlight the importance of prospective studies regarding ACLF in LT, and should encourage UNOS reform. Acute-on-chronic-liver-failure (ACLF) is a specific and common form of liver failure associated with high death rates. Studies have been published using the United States transplant registry (UNOS) to identify and describe outcomes of transplant candidates and recipients with ACLF, and these data are driving policy changes for transplant allocation around the world, but nobody has shown whether these data are reliable. We found that UNOS was not categorizing ACLF in concordance or accurately when compared to chart review, which shows the need for UNOS reform and non-UNOS studies to appropriately inform policies regarding the transplantation of patients with ACLF. [Display omitted] •UNOS studies on ACLF are informing global transplant allocation policies, but the validity of these data is unknown.•We found that ACLF identified by UNOS is only weakly concordant with chart review.•Classification of acute decompensation and brain/respiratory failures are common sources of discordance.•These data highlight the importance of prospective studies regarding ACLF in LT and should encourage UNOS reform