Parameterizing probabilities for estimating age-composition distributions for mixture models

When estimating parameters that constitute a discrete probability distribution {pj}, it is difficult to determine how constraints should be made to guarantee that the estimated parameters { pˆj} constitute a probability distribution (i.e., pˆj>0, Σ pˆj =1). For age distributions estimated from mixtures of length-at-age distributions, the EM (expectationmaximization) algorithm (Hasselblad, 1966; Hoenig and Heisey, 1987; Kimura and Chikuni, 1987), restricted least squares (Clark, 1981), and weak quasisolutions (Troynikov, 2004) have all been used. Each of these methods appears to guarantee that the estimated distribution will be a true probability distribution with all categories greater than or equal to zero and with individual probabilities that sum to one. In addition, all these methods appear to provide a theoretical basis for solutions that will be either maximum-likelihood estimates or at least convergent to a probability distribut

The 'Baird Memorial"

In mid 1903, during the annual meeting of the American Fisheries Society, AFS members, U.S. Fish Commission (USFC) staff, and other interested persons gathered at Woods Hole, Mass., to dedicate a permanent memorial to Spencer F. Baird, founder of the U.S. Fish Commission. President of the AFS that year was the USFC Commissioner George M. Bowers. Speakers were Chicago attorney E. W. Blatchford; W. K. Brooks, a professor at Johns Hopkins University, Baltimore, Md., who had conducted research at the Commission's Beaufort Laboratory; and, very briefly, the noted fish culturists Frank N. Clark of Michigan and Livingston Stone of Vermont. The following record of the dedication ceremony appeared as a twopart article in The Fishing Gazette, 22 and 29 August 1903.

An Economic Analysis of Texas Shrimp Season Closures

Management of the Texas penaeid shrimp fishery is aimed at increasing revenue from brown shrimp, Penaeus aztecus, landings and decreasing the level of discards. Since 1960 Texas has closed its territorial sea for 45-60 days during peak migration of brown shrimp to the Gulf of Mexico. In 1981 the closure was extended to 200 miles to include the U.S. Exclusive Economic Zone. Simulation modeling is used in this paper to estimate the changes in landings, revenue, costs, and economic rent attributable to the Texas closure. Four additional analyses were conducted to estimate the effects of closing the Gulf 1- to 4-fathom zone for 45 and 60 days, with and without effort redirected to inshore waters. Distributional impacts are analyzed in terms of costs, revenues, and rents, by vessel class, shrimp species, vessel owner, and crew.

Effects of the Santa Barbara, Calif., Oil Spill on the Apparent Abundance of Pelagic Fishery Resources

Many studies have been made of the effects of oil on marine invertebrates, plants (marine algae and phytoplankton), and vertebrates such as seabirds and marine mammals. An excellent review of these findings, which includes some references to fish and pathological effects of aromatic hydrocarbons, has been published by the Royal Society, London (Clark, 1982). That review dealt with the environmental effects of such major oil spills or releases such as those by the tankers Torry Canyon (119,000 t) on the south coast of England, Metula (50-56,000 t) in the Straits of Magellan, Argo Merchant (26,000 t) off Cape Cod, and the super tanker Amoco Cadiz (223,000 t) on the coast of northern Brittany. Those spills were studied to determine their effect on living resources. In contrast there are few references on the impact of oil spills on pelagic fishery resources.

Simulated Economic Impact of TED Regulations on Selected Vessels in the Texas Shrimp Fishery

Shrimp fishermen trawling in the Gulf of Mexico and south Atlantic inadvertently capture and kill sea turtles which are classified as endangered species. Recent legislation requires the use of a Turtle Excluder Device(TED) which, when in place in the shrimp trawl, reduces sea turtle mortality. The impact of the TED on shrimp production is not known. This intermediate analysis of the TED regulations using an annual firm level simulation model indicated that the average Texas shrimp vessel had a low probability of being an economic success before regulations were enacted. An assumption that the TED regulations resulted in decreased production aggravated this condition and the change in Ending Net Worth and Net Present Value of Ending Net Worth before and after a TED was placed in the net was significant at the 5 percent level. However, the difference in the Internal Rate of Return for the TED and non-TED simulations was not significant unless the TED caused a substantial change in catch. This analysis did not allow for interactions between the fishermen in the shrimp industry, an assumption which could significantly alter the impact of TED use on the catch and earnings of the individual shrimp vessel.

Quase imperceptível: arte participativa e ficção

Esta dissertação levantou um conjunto de questões relacionadas à reflexão do meu processo artístico, tendo como ponto de partida as imagens poéticas da casa, do dormir, do desabrigo, da invisibilidade e da visibilidade que culminaram em trabalhos acerca dos moradores de rua, da acessibilidade e do uso da cidade. Para analisar as experiências artísticas participativas realizadas em âmbito urbano, foi apresentado um estudo da produção de artistas como Flávio de Carvalho, Lygia Clark e Hélio Oiticica, assim como os conceitos de site specific e site oriented (KWON 1998). Acerca dos trabalhos que envolvem relações e propostas de convivência, foi acessado o livro Estética Relacional (BOURRIAUD 2009) e o texto Antagonismos e Estética Relacional (BISHOP 2004). O ato de ouvir e as histórias narradas durante as propostas participativas aproximaram o estudo da ideia de autoficção (DOUBROVSKY 1977) e da escrita de si (FOULCAULT 2002). A relação com o desenho foi observada como produção de sentido, assim como foi problematizado o papel do artista a partir da observação do papel do mediador, revelando possibilidades outras de definição com base nos conceitos de participação total (OITICICA 1967), e artista-etc. (BASBAUM 2013).