International Evidence on Stochastic and Deterministic Monetary Neutrality.

We analyze the issue of the impact of multiple breaks on monetary neutrality results, using a long annual international data set. We empirically verify whether neutrality propositions remain addressable (and if so, whether they hold or not), when unit root tests are carried out allowing for multiple structural breaks in the long-run trend function of the variables. It is found that conclusions on neutrality are sensitive to the number and location of breaks. In order to interpret the evidence for structural breaks, we introduce a notion of deterministic monetary neutrality, which naturally arises in the absence of permanent stochastic shocks to the variables.Deterministic and Stochastic Neutrality and Superneutrality of Money, Unit Roots, Structural Breaks, Resampling Methods

Polydispersity Effects in the Dynamics and Stability of Bubbling Flows

The occurrence of swarms of small bubbles in a variety of industrial systems enhances their performance. However, the effects that size polydispersity may produce on the stability of kinematic waves, the gain factor, mean bubble velocity, kinematic and dynamic wave velocities is, to our knowledge, not yet well established. We found that size polydispersity enhances the stability of a bubble column by a factor of about 23% as a function of frequency and for a particular type of bubble column. In this way our model predicts effects that might be verified experimentally but this, however, remain to be assessed. Our results reinforce the point of view advocated in this work in the sense that a description of a bubble column based on the concept of randomness of a bubble cloud and average properties of the fluid motion, may be a useful approach that has not been exploited in engineering systems.Comment: 11 pages, 2 figures, presented at the 3rd NEXT-SigmaPhi International Conference, 13-18 August, 2005, Kolymbari, Cret

H. S. Churchill, La ciudad es su población, Buenos Aires, Ed. Infinito, 1958, 243 p.

Fil: Herrera de Soria, María E.. Universidad Nacional de Cuyo. Facultad de Filosofía y Letra

Deslizamiento de cobertura en el Sinclinorio Mesocenozoico de Sevaruyo-Rio Mulato (Altiplano central de Bolivia)

Una cuenca cenozoica muy subsidente caracteriza al sector septentrional del Altiplano de Bolivia, mientras que otras con menor subsidencia, ocupan el sector meridional. En la region central del Altiplano, un potente conjunto de capas meso-cenozoicas era considerado como el relleno de la "Cuenca de Sevaruyo-Rio Mulato", deformado en un amplio sinclinorio al oeste de la Cordillera Oriental. Interpretamos este conjunt plegado como el resultado de un deslizamiento plurikilometrico de la cobertura de Cretacico superior-Paleogeno, la cual resbala desde el margen occidental de la Cordillera Oriental (collapse). El deslizamiento y el plegamiento de esta cobertura se realizan mediante un despegue en la capas saliferas de Turoniano (Fm. Aroifilla). El transporte, hacia el oeste, es sincronico de la sedimentacion de las capas continentales del Paleogeno y pp Mioceno. A fines del Oligoceno, las discordancias angulares y las intercalaciones de conglomerados con clastos de Cretacico y de Palezoico marcan una etapa dentro de un proceso continuo de deformacion, erosion y sedimentacion durante el cual un hundimiento progresivo, al oeste, esta acompa¤ado de un levantamiento al este. El basculamiento de un bloque plurikilometrico de la corteza puede explicar, a la vez: 1) el deslizamiento hacia el oeste de la cobertura de un dominio positovo oriental, 2) la fuerte disimetria de la "Cuenca" cenozoica occidental, y 3) el relleno progresivo de dicho dominio subsidente porlos productos de la erosion de los sectores elevados. El proceso esta marcado por la sucesiva erosion y resedimentacion de las capas rojas del Paleoceno-Eoceno, luego del Cretacico y, despues, del Paleozoico. La deformacion gravitacional, la erosion y la subsidencia disimetrica resultarian de la evolucion geodinamica del antepais de un importante cabalgamiento del "Macizo Precambrico de Arequipa". Progresando del oeste hacia el este durante el Paleogeno, el bloque Precambrico de Arequipa se superpone y sobrecarga al margen occidental de un bloque de Precambrico y Hercinico mas oriental, el cual esta, a su vez, empujado, flexurado y basculado. Dicho bloque oriental, en relevo (piggyback sequence), forma otro gran cabalgamiento cortical hacia el este. El basculamiento de este bloque constituye el origen del despegue y del deslizamiento de la cobertura de Cretacico terminal-Paleogeno, que preceden la erosion del sustrato Paleozoico-Cretacico inferior en el sector oriental elevado, fuente principal de los aportes en la potente sedimentacion observada en el dominio occidental en proceso de hundimiento. (Résumé d'auteur)

The use of zooplankton metrics to determine the trophic status and ecological potential: An approach in a large Mediterranean watershed.

In the European Water Framework Directive, zooplankton was not included as a Biological Quality Element despite its important place in the aquatic trophic web. In the present study on zooplankton abundances and biomasses, we used several metrics to test their ability to detect differences among trophic statuses and ecological potential levels, and collected a large sum of data in more than 60 reservoirs at Ebro watershed, on more than 300 sampling occasions over 10 years. Our results indicate that most zooplankton metrics are correlated to environmental variables that determine reservoirs' trophic states, especially chlorophyll a and total phosphorus. The metrics with better sensitivity to differentiate trophic states and ecological potential levels were ZOO (total zooplankton), LZOO (large zooplankton), CLAD (cladocerans), and ZOO:CHLA (zooplankton:chlorophyll a ratio). Microcrustacean metrics such as DAPHN (Daphnia), COP (copepods), CYCLO (cyclopoids), and CALA (calanoids) were good at differentiating between high and low water quality in trophic status (oligotrophic-eutrophic) and ecological potential (good or superior-moderate). Thus, zooplankton can be used as a valuable tool to determine water quality; we believe that zooplankton should be considered a Biological Quality Element withinWater Framework Directive monitoring programs for inland waters