A Cooperative Management Solution to a Fishery Commons

A common property resource with open access, such as a fishery, will be used to excess when faced with sufficient demand. This will lead to an excessive amount of effort on the part of the fishery, resulting in a depletion of the stock. This paper discusses the development of a property rights regime for the Atlantic calico scallop, Argopecten gibbus, fishery of Florida. The management solution of the Calico Scallop Conservation Association (CSCA) provides an example of the assignment of property rights to a common property resource without resorting to governmental intervention. In this particular fishery, self-regulation limited early harvesting which would be uneconomic; there may be other fisheries in which self-regulation could be economically efficient and biologically appropriate. While this solution may not be applicable to all common property resources, for those cases which may be similar; the example of the CSCA provides valuable information that may be helpful in establishing a more efficient use of the resource. Some types of government facilitation may also be useful

Real Exchange Rate Effects of Fiscal Policy

This paper develops a framework for analyzing the effects of fiscal policy on the real exchange rate. The short-run impact of various types of fiscal measures are considered as well as the dynamics of adjustment to long-run steady states. The analysis and related simulations suggest that the effect of fiscal policy changes on the real exchange rate can vary widely and will depend closely on a number of structural features, including the degree of asset substitutability,the composition of government spending, and the initial size of the public debt and net external position.

Do Asset-Demand Functions Optimize over the Mean and Variance of Real Returns? A Six-Currency Test

International asset demands are functions of expected returns.Optimal portfolio theory tells us that the coefficients in this relationship depend on the variance-covariance matrix of real returns.But previous estimates of the optimal portfolio (1) assume expected returns constant and (2) are not set up to test the hypothesis of mean-variance optimization. We use maximum likelihood estimation to impose a constraint between the coefficients and the error variance-covariance matrix. For a portfolio of six currencies, we are able statistically to reject the constraint. Evidently investors are either not sophisticated enough to maximize a function of the mean and variance of end-of-period wealth, or else are too sophisticated to do so.

Why Money Announcements Move Interest Rates: An Answer from the Foreign Exchange Market

On a Friday that the Fed announces a money supply greater than had been anticipated, interest rates move up in response. Why? One explanation is that the market perceives the fluctuation in the moneystock as an unintended deviation from the Fed's target growth rate that will be reversed in subsequent periods. The anticipation of this future tightening drives up interest rates today. A second explanation is that the market perceives the increase in the money supply as signalling a higher target growth rate. The expected future inflation rate rises,which is reflected in a higher nominal Interest rate.This paper offers grounds for choosing between the two possible explanations: evidence from the exchange market. Under the first explanation, anticipated future tightening, one would expect the dollar to appreciate against foreign currencies. Under the second explanation,expected inflation, one would expect it to depreciate. We render these claims more concrete by a formal model, a generalization of the Dornbusch overshooting model. Then we use the mark/dollar rate toanswer the question. We find a statistically significant tendency for the dollar to appreciate following positive money supply surprises.This supports the first explanation.

The Functions of the Multiproduct and Rapidly Evolving \u3cem\u3edec-1\u3c/em\u3e Eggshell Gene Are Conserved Between Evolutionarily Distant Species of Drosophila

The Drosophila dec-1 gene encodes multiple proteins that are required for female fertility and proper eggshell morphogenesis. Genetic and immunolocalization data suggest that the different DEC-1 proteins are functionally distinct. To identify regions within the proteins with potential biological significance, we cloned and sequenced the D. yakuba and D. virilis dec-1 homologs. Interspecies comparisons of the predicted translation products revealed rapidly evolving sequences punctuated by blocks of conserved amino acids. Despite extensive amino acid variability, the proteins produced by the different dec-1 homologs were functionally interchangeable. The introduction of transgenes containing either the D. yakuba or the D. virilis dec-1 open reading frames into a D. melanogaster DEC-1 protein null mutant was sufficient to restore female fertility and wild-type eggshell morphology. Normal expression and extracellular processing of the DEC-1 proteins was correlated with the phenotypic rescue. The nature of the conserved features highlighted by the evolutionary comparison and the molecular resemblance of some of these features to those found in other extracellular proteins suggests functional correlates for some of the multiple DEC-1 derivatives

Aortic Coarctation: Recent Developments in Experimental and Computational Methods to Assess Treatments for this Simple Condition

Coarctation of the aorta (CoA) is often considered a relatively simple disease, but long-term outcomes suggest otherwise as life expectancies are decades less than in the average population and substantial morbidity often exists. What follows is an expanded version of collective work conducted by the authors\u27 and numerous collaborators that was presented at the 1st International Conference on Computational Simulation in Congenital Heart Disease pertaining to recent advances for CoA. The work begins by focusing on what is known about blood flow, pressure and indices of wall shear stress (WSS) in patients with normal vascular anatomy from both clinical imaging and the use of computational fluid dynamics (CFD) techniques. Hemodynamic alterations observed in CFD studies from untreated CoA patients and those undergoing surgical or interventional treatment are subsequently discussed. The impact of surgical approach, stent design and valve morphology are also presented for these patient populations. Finally, recent work from a representative experimental animal model of CoA that may offer insight into proposed mechanisms of long-term morbidity in CoA is presented