The Gulf of Mexico Grouper Fisheries: Heterogeneous Fleet and Expectations in Fishermen's Decision

This study focuses on Gulf of Mexico Fishermen's expectations about their revenues and risks when participating in the grouper fishery using handlines or longlines. Results indicated that expected revenues follow a seasonnal and a spatial pattern. Fishermen using longline are risk averse while handliners are risk takers.Resource /Energy Economics and Policy,

Disintegration of concrete construction induced by acid mine drainage attack

Abstract: In this paper, microanalytical investigation was conducted on disintegrated field concrete that had been used to construct a weir within a coal mine in South Africa. The concrete was in contact with polluted mine water, commonly referred to as acid mine drainage (AMD). Accordingly, the concrete weir had been exposed to dynamic conditions associated with flowing AMD. Investigations were conducted by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD). The field concrete samples examined consisted of soft broken concrete chunks and whitish powdery substance that had crystallized and formed a surface coating on the widely cracked locations of the deteriorated concrete. No evidence of sulphate attack or pyrite oxidation was found in the investigation; acid attack mechanism was diagnosed

Effet de deux types d’insecticides sur la mycorhization arbusculaire et le développement de deux variétés de pomme de terre (Solanum tuberosum)

Cette étude a été menée en serre pour évaluer l’effet de deux types d’insecticides sur la mycorhization et le développement de deux variétés de pomme de terre (Aïda et Atlas). Les insecticides carbofuran et chlorpyriphos-éthyl, respectivement systémiques et contacts, ont été appliqués au sol à différentes stades d’inoculation du champignon Glomus mosseae. Le pourcentage de mycorhization, la biomasse aérienne, lenombre et le calibre des minitubercules ont été évalués après 60 jours de culture. L’application du carbofuran ou du chlorpyriphos-éthyl 21 jours avant ou après l’inoculation du champignon induit une diminution significative du pourcentage de colonisation mycorhizienne chez toutes les deux variétés. Cependant, cette baisse est plus importante avec les  traitements de l’insecticide de contact après inoculation et de l’insecticidesystémique effectué avant inoculation. Cette tendance s’est répercutée sur la biomasse aérienne et le nombre des minitubercules. Le calibre des minitubercules présente une variabilité de réponse selon la variété de pomme de terre et le type d’insecticide. Ce travail a permis de déterminer le moment compatible de l’inoculation de Glomus mosseae avec  l’application des insecticides au sol chez les variétés Aïda et Atlas de la pomme de terre.© 2013 International Formulae Group. All rights reserved.Mots clés: Glomus mosseae, carbofuran, chlorpyriphos-éthyl, Aïda, Atlas

An Inverse Almost Ideal Demand System for Oysters in the United States: An Empirical Investigation of the Impacts of Mandatory Labels

In 1991, mandatory warning labels were imposed on the sale of oysters harvested from the Gulf of Mexico. Using an IAIDS model, this paper investigates the impact of these labels on the demand for Gulf product as well related oyster products (the Chesapeake, the Pacific, and imports).Demand and Price Analysis,

A concrete reactive barrier for acid mine drainage treatment

Abstract: Pervious concrete was investigated for potential use as a permeable reactive barrier (PRB) for treatment of acid mine drainage (AMD). Pervious concrete mixtures of varied water-cement ratios = 0.50, 0.40, 0.35, 0.30, 0.27 and cement contents = 300, 360, 380, 400 kg/m3 were prepared. Dolomite and granite aggregates types of 9.5 mm size were employed. Tests done were density, compressive strength, porosity. Water treatment was determined by analysis of the influent and effluent AMD after passage through the pervious concrete. It was found that a filter thickness of at least 500 mm was required to increase the pH of acidic mine water from 2.8 pH to 5 - 7 pH value, and corresponding reduction in electrical conductivity. When used in the filter mix design, the granite aggregate gave better treatment performance compared to the dolomite aggregate. The concrete PRB treatment led to effective removal of major metals from the AMD. The treatment reduced the metals in the AMD by 30% SO4, 99% Fe, 50-83% Mn, 85% Ca, 30% TDS. There was, however, a noticeable increase in magnesium concentration in the water effluent by 49-66% Mg. These results are short-term tests and further work is underway on the system’s life expectancy

Responses of potatoes plants inoculated with arbuscular mycorrhizal fungi and litter in greenhouse

A pot experiment was set to examine the impact of the foliar litter (Hardwickia binata and Azadirachta indica) and an arbuscular mycorrhizal (AM) fungus on the development of two varieties of potato plants (Aida, Atlas). Three litter doses (0, 25 and 50 g) were applied to the pots after bedding plantlets. The plants were inoculated with AM, Glomus aggregatum. Mycorrhizal colonization, shoot dry weight, size and number of minitubers were evaluated after 12 weeks on the potato growth. Results show that shoot dry weight of plants was improved by litter of the H. binata at 25 and 50 g. Thus, A. indica litter increased size of plants Aida at 50 g and the minitubers numbers Atlas at 25 g. On the other hand, root colonization decreased with increase in the dose of litter with both varieties of potato.Key words: Arbuscular mycorrhizal fungi, potato, litter, micropropagation

Shielding Calculations on Waste Packages – The Limits and Possibilities of different Calculation Methods by the example of homogeneous and inhomogeneous Waste Packages

For nuclear waste packages the expected dose rates and nuclide inventory are beforehand calculated. Depending on the package of the nuclear waste deterministic programs like MicroShield® provide a range of results for each type of packaging. Stochastic programs like “Monte-Carlo N-Particle Transport Code System” (MCNP®) on the other hand provide reliable results for complex geometries. However this type of program requires a fully trained operator and calculations are time consuming. The problem here is to choose an appropriate program for a specific geometry. Therefore we compared the results of deterministic programs like MicroShield® and stochastic programs like MCNP®. These comparisons enable us to make a statement about the applicability of the various programs for chosen types of containers. As a conclusion we found that for thin-walled geometries deterministic programs like MicroShield® are well suited to calculate the dose rate. For cylindrical containers with inner shielding however, deterministic programs hit their limits. Furthermore we investigate the effect of an inhomogeneous material and activity distribution on the results. The calculations are still ongoing. Results will be presented in the final abstract