Declining Volatility, a General Property of Disparate Systems: From Fossils, to Stocks, to the Stars

There may be structural principles pertaining to the general behavior of systems that lead to similarities in a variety of different contexts. Classic examples include the descriptive power of fractals, the importance of surface area to volume constraints, the universality of entropy in systems, and mathematical rules of growth and form. Documenting such overarching principles may represent a rejoinder to the Neodarwinian synthesis that emphasizes adaptation and competition. Instead, these principles could indicate the importance of constraint and structure on form and evolution. Here we document a potential example of a phenomenon suggesting congruent behavior of very different systems. We focus on the notion that universally there has been a tendency for more volatile entities to disappear from systems such that the net volatility in these systems tends to decline. We specifically focus on origination and extinction rates in the marine animal fossil record, the performance of stocks in the stock market, and the characters of stars and stellar systems. We consider the evidence that each is experiencing declining volatility, and also consider the broader significance of this.Comment: Accepted for publication in Palaeontology. 13 pages, 3 figure

Shifts between gelatinous and crustacean plankton in a coastal upwellin region

proyectos RADIALES (IEO) y EURO-BASIN (Ref. 264933, 7FP)Variability in the dominance of copepods vs. gelatinous plankton was analysed using monthly time-series covering the last 55 years and related to changes in climatic, oceanographic, and fishery conditions in the upwelling region of Galicia (NW Spain). Seasonality was generally the main component of variability in all groups, both along the coast and in the nearby ocean, but no common long-term trend was found. Coastal copepods increased since the early 1990s, and gelatinous plankton increased in the ocean during the 1980s. Different trends were found for gelatinous plankton in two coastal sites, characterized by increases in either medusae or tunicates. In all series, multiyear periods of relative dominance of gelatinous vs. copepod plankton were evident. In general, copepod periods were observed in positive phases of the main modes of regional climatic variability. Conversely, gelatinous periods occurred during negative climatic phases. However, the low correlations between gelatinous plankton and climatic, oceanographic, or fishery variables suggest that local factors play a major role in their proliferations.7FP, IEOPreprin

Fast, Multiphase Volume Adaptation to Hyperosmotic Shock by Escherichia coli

All living cells employ an array of different mechanisms to help them survive changes in extra cellular osmotic pressure. The difference in the concentration of chemicals in a bacterium's cytoplasm and the external environment generates an osmotic pressure that inflates the cell. It is thought that the bacterium Escherichia coli use a number of interconnected systems to adapt to changes in external pressure, allowing them to maintain turgor and live in surroundings that range more than two-hundred-fold in external osmolality. Here, we use fluorescence imaging to make the first measurements of cell volume changes over time during hyperosmotic shock and subsequent adaptation on a single cell level in vivo with a time resolution on the order of seconds. We directly observe two previously unseen phases of the cytoplasmic water efflux upon hyperosmotic shock. Furthermore, we monitor cell volume changes during the post-shock recovery and observe a two-phase response that depends on the shock magnitude. The initial phase of recovery is fast, on the order of 15–20 min and shows little cell-to-cell variation. For large sucrose shocks, a secondary phase that lasts several hours adds to the recovery. We find that cells are able to recover fully from shocks as high as 1 Osmol/kg using existing systems, but that for larger shocks, protein synthesis is required for full recovery

Qualidade das águas residuárias do processo de armazenagem prévia, por imersão, de frutos do cafeeiro

O armazenamento prévio consiste na manutenção dos frutos do cafeeiro recém-colhidos imersos em água, possibilitando o ajuste entre o volume de frutos colhidos e a capacidade de processamento disponível, sem prejuízo à qualidade final dos grãos. Neste trabalho, objetivou-se avaliar algumas características químicas e bioquímicas das águas residuárias geradas no processo, visando avaliar a necessidade de seu tratamento para lançamento em corpos hídricos ou as possibilidades de aproveitamento como fertilizante agrícola.Na geração da água residuária, foram utilizados lotes de frutos de diferentes características e origens, sendo que os períodos de armazenagem avaliados variaram de 1 a 5 dias. As variáveis quantificadas nas águas residuárias foram DBO, DQO e as concentrações de P, N, K e Na. Com base nos resultados obtidos e nas condições estabelecidas para o experimento, pôde-se concluir que a concentração dos nutrientes na água residuária de imersão varia com o estágio de maturação dos frutos e, no geral, com o grau de deterioração do produto, indicando uso potencial para fertirrigação de culturas agrícolas.To maintain the final grain quality, the harvested coffee cherry are stored immersed in water, to adjust harvested volume and the processing capacity. This study reports some chemical and biochemical characteristics of the water left after storage, to assist decision making for its treatment for river discharge or for agricultural use such as fertilizing. Coffee cherries of different characteristics and origins were used, and BOD, COD and concentration of P, N, K and Na was determined after the storage period of 1 to 5 days. The data showed that the concentration of the nutrients in the immersion water is related to fruit maturation and, in general, also to the degree of cherry deterioration, and this water has potential for fertirrigatio