PREMIUMS/DISCOUNTS AND PREDICTIVE ABILITY OF THE SHRIMP FUTURES MARKET

Seafood futures contracts are a novelty in the derivative markets, having shrimp as their only exponent. Unfortunately, shrimp futures contracts have suffered a disappointing start. The analyses focus on testing whether premiums/discounts for non-par deliverable shrimp size categories can eliminate cash price differentials, and whether the shrimp futures market can predict cash prices without bias. Results indicate ineffective premiums/discounts and predictive bias. These results and the momentous changes taking place in the seafood industry are contrasted to discuss the viability of seafood futures contracts.Agribusiness,

Approximation of proximities by aggregating T-indistinguishability operators

For a continuous Archimedean t-norm T a method to approximate a proximity relation R (i.e. a reflexive and symmetric fuzzy relation) by a T-transitive one is provided. It consists of aggregating the transitive closure R of R with a (maximal) T-transitive relation B contained in R using a suitable weighted quasi-arithmetic mean to maximize the similarity or minimize the distance to R.Peer Reviewe

Zr-metal adhesion on graphenic nanostructures

3 pages, 3 figures.-- PACS nrs.: 68.35.Np, 61.46.Fg, 61.46.Df.Our high resolution transmission electronic microscopy studies of multiwall carbon nanotubes show, after the growth of zirconia nanoparticles by a hydrothermal route, the presence of surface Zr, forming an atomically thin layer. Using first-principles calculations we investigate the nature of the Zr–C interaction, which is neither ionic nor covalent, and the optimal coverage for the Zr metal in a graphene flake. This preferred coverage is in agreement with that deduced from electron energy loss spectra experiments. We show also that the amount of charge transferred to the C layer saturates as the Zr coverage increases and the Zr–C bond becomes weaker.We want to acknowledge the support by the ETORTEK (NANOMAT) program of the Basque government, the Intramural Special Project (Reference No. 2006601242), the Spanish Ministerio de Ciencia y Tecnología (MCyT) of Spain (Grant No. Fis 2007-66711-C02-C01), and the European Network of Excellence NANOQUANTA (NM4-CT-2004-500198). Y.S.P. gratefully acknowledges his DIPC grant.Peer reviewe

An Examination of the Shrimp Futures Market

The only two seafood commodities traded in futures markets are frozen white and black tiger shrimps on the Minneapolis Grain Exchange (MGE). These two contracts, however, have failed to attract the expected trade volume based on the underlying shrimp cash market flow. First, we investigate the hedging effectiveness of these contracts. Then we also try to determine the adequacy of the premiums/discounts for non-par deliveries associated with the various shrimp size categories traded in each contract. Finally, we attempt to determine whether these contracts are unbiased predictors of cash market prices. The analyses indicate that the hedging effectiveness of both contracts is relatively modest. It is concluded that part of the explanation for the performance of the contracts resides in high deliverable category exchange option values, which stem from volatility in the price differentials between size categories. Results indicate ineffective premiums/discounts and poor predic tive ability of both contracts

Impact of the disappearance of urban waste water on a reduced community of Macoma around the islands of the Bidasoa estuary (Bay of Biscay)

In 1993, a study was carried out (Sola et al., unpublished) to evaluate the impact of the urban wastes dumped by the cities of Irun, Hondarribia and Hendaia on the macrobenthic communities around the islands in the Bidasoa estuary (southeast of the Bay of Biscay). Starting in September 2000, these effluents were piped out to sea. To evaluate the extent of this change´s effects, in April 2002, another study was conducted similar to that of the decade before. Its results, as well as the biotic indices used, indicate a clear and rapid recovery of the macrobenthic communities. The stations characterised in 1993 by a complete absence of adult Scrobicularia plana (Da Costa, 1778) now present stable S. plana populations, featuring several age classes.En 1993 se realizó un estudio (Sola et al., inédito) cuyo objetivo era evaluar el impacto del vertido de las aguas residuales urbanas de Irún, Hondarribia y Hendaia sobre las comunidades macrobentónicas de las islas del estuario del Bidasoa (sureste del golfo de Vizcaya). En el año 2000 estos vertidos fueron desviados al mar, lejos del estuario y, para evaluar el efecto de esta reconducción, se repitió en 2002 el trabajo realizado en 1993. Los resultados obtenidos, así como los índices bióticos utilizados, muestran una clara y rápida recuperación de las comunidades bentónicas. Las estaciones que en 1993 se caracterizaban principalmente por la ausencia total o carencia de ejemplares adultos de Scrobicularia plana (Da Costa, 1778) presentan en la actualidad una población estable de S. plana, con varias clases de edad.Instituto Español de Oceanografí

Mortar-based systems for externally bonded strengthening of masonry

Mortar-based composite materials appear particularly promising for use as externally bonded reinforcement (EBR) systems for masonry structures. Nevertheless, their mechanical performance, which may significantly differ from that of Fibre Reinforced Polymers, is still far from being fully investigated. Furthermore, standardized and reliable testing procedures have not been defined yet. The present paper provides an insight on experimental-related issues arising from campaigns on mortar-based EBRs carried out by laboratories in Italy, Portugal and Spain. The performance of three reinforcement systems made out of steel, carbon and basalt textiles embedded in inorganic matrices has been investigated by means of uniaxial tensile coupon testing and bond tests on brick and stone substrates. The experimental results contribute to the existing knowledge regarding the structural behaviour of mortar-based EBRs against tension and shear bond stress, and to the development of reliable test procedures aiming at their homogenization/standardization

Establishing a governance threshold in small-scale fisheries to achieve sustainability

The lack of effective governance is a major concern in small-scale fisheries. The implementation of governance that encompasses the three pillars of sustainability (social, economic, and ecological) is still a worldwide challenge. We examined nine stalked barnacle fisheries (Pollicipes pollicipes) across Southwest Europe to better understand the relationship between governance elements and sustainability. Our results show that nested spatial scales of management, the access structure, co- management, and fisher’s participation in monitoring and surveillance promote sustainability. However, it is not the mere presence of these elements but their level of implementation that drives sustainability. Efforts should be placed in the accomplishment of a minimum combination of local scales of management, access rights through individual quotas, instructive-consultative co- management and functional participation. Surpassing this threshold in future governance structures will start to adequately promote social, economic and ecologically sustainability in small-scale fisheries