Ammonium Ion Complexes of Tetraethyl Resorcarene: An Ab Initio Study

The complexation of various ammonium ions with a resorcarene host was evaluated by ab initio calculations. The approximations of the binding locations and the interaction energies for each guest are reported. The supramolecular complex formation also affects the conformation of the resorcarene host.     

COALITIONS IN INTERNATIONAL FISHERIES MANAGEMENT

Abstract We show that with symmetric agents, noncooperation is the only stable coalition structure in a fishery with more than two countries. In the case of asymmetric fishing nations, partial or full cooperation may be stable even if the number of countries exceeds two. These are important results for recent fisheries economics papers that have not allowed for coalition formation. As an example how of one can use the model, we study the problem of new entrants into Regional Fisheries Management Organizations (RFMOs). We show that depending on the economic structure of the fishery, new entrants may make cooperation more difficult or easier.     

Quantum transport in one-dimensional systems via a master equation approach: Numerics and an exact solution

We discuss recent findings about properties of quantum nonequilibrium steady states. In particular we focus on transport properties. It is shown that the time-dependent density matrix renormalization method can be used successfully to find a stationary solution of Lindblad master equation. Furthermore, for a specific model an exact solution is presented.     

Application of the Floquet theory to multiple quantum NMR of dipolar-coupled multi-spin systems under magic angle spinning

A new analytical Liouville-space representation of the time-propagator under magic angle spinning (MAS) is introduced using the formalized quantum Floquet theory. This approach has the advantage that it is applicable to the analysis of any type of NMR experiment where MAS is combined with multiple-pulse excitation. General relationships describing the spectral parameters in multiple-quantum (MQ) MAS spectra are derived in this representation. Their use is illustrated with an application to double-quantum (DQ) NMR spectra of dipolar-coupled multi-spin systems. Corresponding to the separation of the MAS time-propagator into a rotor modulated and a dephasing component, two distinct mechanisms for DQ excitation are identified. One of them exploits the rotor-modulated component to excite DQ coherences through dipolar-recoupling techniques, which are familiar for spin pairs. Analytical expressions of the integral intensities and linewidths in the resulting DQ sideband pattern are derived in the form of power series expansions of the inverse rotor frequency, of which coefficients depend on structural parameters. In a multi-spin system they can most reliably be extracted in the fast spinning regime. The other mechanism exploits the dephasing component, which is characteristic to multi-spin systems only. This is shown to give rise to DQ coherences by free evolution at full rotor periods. The possibility to exploit it for selective excitation of higher order MQ coherences is discussed. In either case, the dephasing component also leads to residual broadening. The main results of the theoretical developments are demonstrated experimentally on adamantane.     

THE ECONOMICS OF CONFLICTING INTERESTS: NORTHERN BALTIC SALMON FISHERY ADAPTION TO GRAY SEAL ABUNDANCE

The successful conservation of gray seals has led to increased seal‐induced damage to the Atlantic salmon fisheries of the Baltic Sea. This paper addresses the conflict between the conservation of a formerly endangered species, the gray seal, and professional fishermen, whose livelihoods are affected by both seal‐induced damage and salmon fisheries management. We develop a bioeconomic model that incorporates the age structure of Atlantic salmon and gray seal populations. To determine the social optimum, we maximize the discounted net present value of the trap net fishery, taking into account the presence of seals in the form of seal‐induced losses, which we describe using a damage function. By choosing the optimal combination of fishing gear over time, we obtain the socially optimal fishing efforts, salmon stock size, and salmon catch. In addition, we study the private effects of introducing a technology subsidy aimed at mitigating the seal‐salmon conflict. The results suggest that technological adaptation would effectively reduce the cause of the conflict, while a technology subsidy encouraging such adaptation would shift the economic responsibility from individual fishermen to the broader public.     

NONCOOPERATIVE MANAGEMENT OF THE NORTHEAST ATLANTIC COD FISHERY: A FIRST MOVER ADVANTAGE

The point of departure for this analysis is Bjørndal and Lindroos [2012], who developed an empirical bioeconomic model to analyze cooperative and noncooperative management of Northeast Atlantic cod. In their analysis, only constant strategies were analyzed for noncooperative games. In this paper, nonconstant strategies are considered. Moreover, the fishery in question is characterized by cooperative management. What may happen in the real world is that one nation breaks the cooperative agreement by fishing in excess of its quota. Often, it takes time for the other agent to detect this and respond. In this paper, we allow this kind of delayed response into a two‐agent noncooperative game so that, if country 2 exceeds its quota, there will be a time lag before this is detected by country 1; moreover, there may also be a delay until country 1 is able to respond. Results show that the outcome critically depends on the length of these two lags as well as initial conditions.     

RESTRICTED COALITIONS IN THE MANAGEMENT OF REGIONAL FISHERIES ORGANIZATIONS

ABSTRACT. In this paper, we examine a game theoretic setting in which four countries have established a regional organization for the conservation and management of straddling and highly migratory fish stocks as recommended by the United Nations Agreement. These countries consist of two coastal states and two distant water fishing nations (DWFNs). A characteristic function game approach is applied to describe the sharing of the surplus benefits from cooperation. We are specifically interested in the effect of possible coalition restrictions on these shares. According to our results the distant water fishing nations, by individually refusing to join with the coastal states, can considerably improve their negotiation position if their harvesting costs are relatively high and similar. The results show that the DWFNs may have economic reasons for negotiating as a group against coastal states. However, if the coastal states are clearly more efficient than the DWFNs then coalition restrictions may be prevented by coastal states.     

Photo-CIDNP evidence for charge-transfer interaction between synthetic water-soluble porphyrins and guanine

Abstract Photoreactions of aqueous solutions of synthetic water-soluble porphyrins were studied by the ¹H and ¹³C CIDNP technique. Strong polarizations, which were very sensitive to the presence of added acid, were observed on the cationic porphyrins (TMePyPH₂-TAPPH₂) when irradiated through continuous UV-visible light. They resulted from the reverse electron transfer between the semi-oxidized and the semi-reduced species of the derivative. When the experiments were carried out in the presence of nucleobases, guanine (and its derivatives) was the only residue that was polarized. This is thoroughly interpreted in terms of a reversible electron transfer reaction leading to guanine photooxidation by the porphyrin excited triplet state. It was shown to be drastically pH-dependent and was correlated to the redox potential of the porphyrin. It was not affected by the incident wavelength. The reaction proceeded through the intermediate formation of the correlated radical-ion pair: porphyrin radical anion-guanine radical cation. This study suggested that a Type I (free radical) reaction could be one of the primary processes in DNA photosensitization by porphyrins.