Have Niche, Will Travel. New Means of Linking Diet and Ecomorphology Reveals Niche Conservatism in Freshwater Cottoid Fishes.

Evolutionary transitions between habitats have been catalysts for some of the most stunning examples of adaptive diversification, with novel niches and new resources providing ecological opportunity for such radiations. In aquatic animals, transitions from saltwater to freshwater habitats are rare, but occur often enough that in the Neotropics for example, marine-derived fishes contribute noticeably to regional ichthyofaunal diversity. Here, we investigate how morphology has evolved in a group of temperate fishes that contain a marine to freshwater transition: the sculpins (Percomorpha; Cottoidea). We devised a novel method for classifying dietary niche and relating functional aspects of prey to their predators. Coupled with functional measurements of the jaw apparatus in cottoids, we explored whether freshwater sculpins have fundamentally changed their niche after invading freshwater (niche lability) or if they retain a niche similar to their marine cousins (niche conservatism). Freshwater sculpins exhibit both phylogeographical and ecological signals of phylogenetic niche conservatism, meaning that regardless of habitat, sculpins fill similar niche roles in either saltwater or freshwater. Rather than competition guiding niche conservatism in freshwater cottoids, we argue that strong intrinsic constraints on morphological and ecological evolution are at play, contra to other studies of diversification in marine-derived freshwater fishes. However, several intertidal and subtidal sculpins as well as several pelagic freshwater species from Lake Baikal show remarkable departures from the typical sculpin bauplan. Our method of prey categorization provides an explicit, quantitative means of classifying dietary niche for macroevolutionary studies, rather than relying on somewhat arbitrary means used in previous literature.

Tem Nicho, Viaja. Novos Meios de Associar Dieta e Ecomorfologia Revelam Conservadorismo de Nicho em Peixes Cotoides de Água Doce (Have Niche, Will Travel. New Means of Linking Diet and Ecomorphology Reveals Niche Conservatism in Freshwater Cottoid Fishes) Transições evolutivas entre habitats têm sido catalisadores de alguns dos mais impressionantes exemplos de diversificação adaptativa, com novos nichos e recursos proporcionando oportunidade ecológica para tais radiações. Em animais aquáticos, as transições de água salgada para habitats de água doce são raras, mas ocorrem com freqüência suficiente para que, nos Neotrópicos, por exemplo, os peixes marinhos contribuam notavelmente para a diversidade regional da ictiofauna. Aqui, nós investigamos como a morfologia evoluiu em um grupo de peixes temperados que contêm uma transição marinha para a água doce: os esculpentes (Percomorpha; Cottoidea). Nós concebemos um novo método para classificar o nicho alimentar e relacionar os aspectos funcionais das presas aos seus predadores. Juntamente com medidas funcionais do aparato de mandíbula em cotoides, exploramos se os esculpentes de água doce mudaram fundamentalmente seu nicho depois de invadi-la (labilidade de nicho) ou se eles mantêm um nicho semelhante aos seus primos marinhos (conservadorismo de nicho). Os esculpentes de água doce exibem sinais filogeográficos e ecológicos de conservadorismo filogenético de nicho, o que significa que, independente do habitat, os esculpentes preenchem papéis ecológicos semelhantes em água salgada ou doce. Mais do que a concorrência guiando o conservadorismo de nicho em cotoides de água doce, argumentamos que fortes restrições intrínsecas à evolução morfológica e ecológica estão em jogo, em contraste com outros estudos de diversificação em peixes de água doce derivados do mar. No entanto, vários esculpentes intertidais e subtidais, bem como várias espécies pelágicas de água doce do Lago Baikal, mostram notáveis desvios do típico bauplan dos esculpentes. Nosso método de categorização de presas fornece um modo explícito e quantitativo de classificar o nicho alimentar para estudos macroevolutivos ao invéz de depender de meios arbitrários usados na literatura anterior. Translated to Portuguese by G. Sobral (gabisobral@gmail.com).

An inventory of long-lived radionuclides residual from underground nuclear testing at the Nevada test site, 1951-1992.

An inventory of long-lived radionuclides produced by 828 underground nuclear tests conducted at the Nevada test site (NTS) from 1951 to 1992 includes residual tritium, fission products, actinides, and activation products. Recently, the US Department of Energy approved the declassification of the NTS radionuclide inventory by principal geographic test centers. This permits unclassified publication of radionuclide totals for the Yucca Flat, Pahute Mesa-Area 19, Pahute Mesa-Area 20, Frenchman Flat, and Rainier Mesa/Shoshone Mountain testing locations. Activities are reported as of September 23, 1992, the date of the last underground nuclear test conducted at the NTS, and September 23, 2492, after 500 years of radioactive decay. The availability of these data affords an opportunity for the analysis of the radiologic source term within the boundaries of local hydrogeologic units and provides insight to where radionuclides are sited relative to potential exposure pathways.

Psychological factors associated with maintenance of improved health behaviors in postcoronary patients.

Multiple regression analyses of interview data determined whether certain behavioral, personality, and social support variables were associated with maintenance of changes in exercise, weight loss, and smoking cessation for a group of postcoronary patients. The results indicate that the psychological reactions to success or failure at one health behavior change, especially smoking, may affect the ability to maintain changes in other health behaviors. Also, the affective psychological sequelae to heart attacks may disrupt attempts to change health habits or may themselves be alleviated once successful health changes are achieved.

El chichon: composition of plume gases and particles.

Aircraft measurements were made of trace gases, atmospheric particles, and condensed acid volatiles in the plume of El Chichón volcano, Chiapas, Mexico, in November 1982. Hydrogen sulfide was the primary gaseous sulfur species in the plume at the time of collection. Concentrations of 28 elements were determined by neutron activation analysis of particulate material from the plume. Rates of trace element emission to the atmosphere for each species were estimated by normlization to the simultaneously determined total sulfur emission rate. The volatile elements sulfur, chlorine, arsenic, selenium, bromine, antimony, iodine, tungsten, and mercury were enriched relative to bulk pyroclastic material by factors of 60 to 20,000. Arsenic, antimony, and selenium were associated predominantly with small (>/= 3 micrometer) particles. Calcium and sodium were present almost exclusively on larger particles and aluminum and manganese were bimodally distributed. Ashladen particulate material injected into the stratosphere during the early violent eruptions was enriched by factors of 10 to 30 relative to ash in some of the same elements observed in the quiescent plume.