Ecological dynamics of decision-making in the sport of sailing exemplifies emergent, conditionally coupled, co-adaptive behaviours. In this study, observation of the coupling dynamics of paired boats during competitive sailing showed that decision-making can be modelled as a self-sustained, co-adapting system of informationally coupled oscillators (boats). Bytracing the spatial-temporal displacements of the boats, time series analyses (autocorrelations, periodograms and running correlations) revealed that trajectories of match racing boats are coupled more than 88% of the time during a pre-start race, via continuous, competing co-adaptions between boats. Results showed that both the continuously selected trajectories of the sailors (12 years of age) and their categorical starting point locations were examples of emergent decisions. In this dynamical conception of decision-making behaviours, strategic positioning (categorical) and continuous displacement of a boat over the course in match-race sailing emerged as a function of interacting task, personal and environmental constraints. Results suggest how key interacting constraints could be manipulated in practice to enhance sailors' perceptual attunement to them in competition.

O objetivo deste trabalho foi processar e avaliar a estabilidade da farinha de banana verde durante noventa dias de armazenamento a temperatura ambiente (±26ºC) como opção no aproveitamento do excedente de produção contribuindo com a minimização do desperdício. As amostras foram armazenadas em embalagens de polietileno tereftalato (PET), com capacidade 300g. Foram realizados dois tipos de avaliações: determinações físico-químicas (umidade, atividade de água, pH, acidez, proteína, lipídios, cinzas, carboidratos) e análises microbiológicas, no dia do processamento e durante todo o período de armazenamento, com intervalo de 30 dias. De acordo com os resultados obtidos, ocorreram alterações pouco significativas durante o armazenamento, sendo os teores acidez, atividade de água e umidade os parâmetros afetados significativamente.

Recebido em 23/3/05; aceito em 13/9/05; publicado na web em 14/3/06 THE EVALUATION OF POLYOLEFIN PHOTODEGRADATION WITH NATURAL AND ARTIFICIAL EXPOSURE. Samples of polypropylene (PP) and low-density polyethylene (LDPE) were submitted to ultraviolet radiation, in the natural environment and also in the laboratory. Chemical modifications were quantified by the carbonyl index (CI), mechanical properties and melt flow index. The degradation in the laboratory was comparatively faster than in the environment for both types of polymers. The accelerating factor was determined for the various properties investigated. This parameter, however, showed a large variation with the degradation criteria and the type of polymer. The existence of a "universal accelerating factor", therefore, was not observed in the current study.Keywords: polypropylene; low-density polyethylene; photodegradation. INTRODUÇÃOTodos os polímeros orgânicos não estabilizados são degradados sob exposição à luz solar na presença de oxigênio. Entretanto, as taxas de degradação fotooxidativa dependem fortemente da natureza química do polímero, com a vida útil variando desde poucos meses para o polipropileno, até alguns anos para o politereftalato de etileno (PET), poli(metacrilato de metila) (PMMA) e o politetrafluoretileno 1,2 . Os problemas da fotodegradação têm aumentado com o crescente uso de polímeros em aplicações exteriores aliado à necessidade da redução de custos com aditivos fotoestabilizantes. Durante o processo degradativo ocorrem mudanças físicas e químicas no polímero que levam à descoloração, fissuramento, perda de brilho e queda de resistência mecânica. Tais fenômenos estão quase sempre associados a processos de cisão de cadeia e, em alguns casos, ocorrem também reticulações 2 . A investigação da degradação foto-oxidativa de polímeros é um dos principais elementos que subsidiam o desenvolvimento do produto e sua expectativa de vida útil. Ao se expor o material às intempéries e avaliar os efeitos nas suas propriedades busca-se obter uma fotografia do que aconteceria durante a aplicação desse produto. Nesse tipo de investigação utilizam-se a exposição no ambiente natural e a exposição simulada, realizada em laboratório. Nas exposições em laboratório, as variáveis mais importantes são tipo de fonte geradora de radiação ultravioleta, intensidade de radiação, temperatura, umidade e ciclos térmicos [3][4][5][6][7][8] . A resposta do material à exposição depende, portanto, da intensidade dessas variá-veis. É comum a intensificação desses fatores para aceleração da fotodegradação e, assim, se obter resultados mais rápidos. Outra maneira de se investigar a resistência fotoquímica dos polímeros é a exposição ambiental, onde os diversos constituintes do ambiente, como radiação ultravioleta, luz visível, temperatura, intempé-ries, umidade, etc, afetam a estrutura química do polímero provocando degradação. A intensidade desses elementos do ambiente natural varia significativamente com o local de exposição, a época do ano e o período do dia, de tal modo qu...

Several bacterial isolates, with an optimum growth temperature of about 50°C, were recovered from the marine hot spring at Ferraria on the island of São Miguel in the Azores. The geothermal water emerged from a porous lava flow and rapidly cooled in contact with seawater except at low tide. The bacterial species represented by strains FRR-10 T and FRR-11 was nonpigmented, strictly aerobic, and organotrophic. Several genes, bchZ, pufB, pufA, pufL, or pufM, encoding the photosynthetic reaction center proteins and the core light-harvesting complexes were not detected in these strains. The organism oxidized thiosulfate to sulfate with enhancement of growth. The organism did not require additional NaCl in the culture medium for growth, but NaCl at 1.0% enhanced growth. Phylogenetic analyses using the 16S rRNA gene sequence of strain FRR-10 T indicated that the new organism represented a new species of the ␣-3 subclass of the Proteobacteria and that it branches within the species of the genus Rhodovulum. The contradiction of classifying an organism which branches within the radiation of the genus Rhodovulum but does not possess the hallmark characteristics of this genus is discussed. However, the absence of several of these characteristics, namely, the lack of photosynthesis and pigmentation, which could be related to colonization of dark environments, and growth at high temperatures, leads to our proposal that strains FRR-10 T and FRR-11 should be classified as a new species of a novel genus, Albidovulum inexpectatum, representing, at present, the most thermophilic organism within the ␣-3 subclass of the Proteobacteria.A large number of thermophilic organisms have been isolated from continental hydrothermal areas where the levels of sodium are very low, as well as from shallow or abyssal marine hydrothermal vents where NaCl can reach the levels of seawater. Most of the organisms isolated and described from marine hydrothermal sites are slightly halophilic and have optimum growth temperatures above 70°C and some, namely Methanopyrus kandleri and Pyrolobus fumarii, have optimum temperatures for growth above 100°C (2, 20). However, many marine hot springs have lower vent temperatures and the organisms isolated from these are slightly or moderately thermophilic. These organisms do not elicit as much interest as those that grow at temperatures around 100°C, although new, slightly or moderately thermophilic species increase our perception of microbial biodiversity and may have characteristics and phylogenetic affiliations that are sometimes unexpected.We recently isolated several slightly thermophilic nonpigmented organisms from the marine hot spring at Ferraria on the island of São Miguel in the Azores that did not produce carotenoids, bacteriochlorophyll a (Bchl a), or puf genes that encode the photosynthetic reaction center proteins and the core light-harvesting complexes. These organisms were not phototrophic but they are, based on 16S rRNA gene sequence analysis, members of the genus Rhodovulum, which comprises the sp...

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