Spatial and temporal dynamics of suspended load at-a-cross-section: The lowermost Ebro River (Catalonia, Spain)

AbstractSuspended load dynamics were analyzed for the period 2007–2009 in a semi-meandering cross-section under different hydrological conditions. Samples were collected at four different points of the cross-section. During “low discharges” (≤600 m3/s) suspended load samples were collected at-a-monthly basis, whereas at “high discharges” (>600 m3/s) sampling was conducted intensively (at-a-daily basis during the first stages of the flood event). Results indicated that during low discharges, both organic and inorganic suspended load concentrations tended to be uniformly distributed across the fluvial section; but during high discharges, two distinct areas were found: an area extending from the “Inner-bank” to the “Channel centre” (Area-I) with higher suspended concentrations (organic and inorganic) than those recorded in the “Outer bank” (Area-II). This phenomenon was likely related to the formation of secondary flow velocity cells and the activation of new sources of sediment. In addition, a non-significant relationship between organic suspended load and water flow was observed in the outer-bank. At-a-monthly basis, the analysis of the suspended load showed the existence of an intra-annual cycle of the inorganic concentrations, with a progressive increase from October to March followed by a decrease from March to September. Nevertheless, the organic suspended load did not show any trend, being equally distributed along the year, suggesting that other sources of organic matter besides phytoplankton are predominant

Density functional theory in transition-metal chemistry: a self-consistent Hubbard U approach

Transition-metal centers are the active sites for many biological and inorganic chemical reactions. Notwithstanding this central importance, density-functional theory calculations based on generalized-gradient approximations often fail to describe energetics, multiplet structures, reaction barriers, and geometries around the active sites. We suggest here an alternative approach, derived from the Hubbard U correction to solid-state problems, that provides an excellent agreement with correlated-electron quantum chemistry calculations in test cases that range from the ground state of Fe$_2$ and Fe$_2^-$ to the addition-elimination of molecular hydrogen on FeO$^+$. The Hubbard U is determined with a novel self-consistent procedure based on a linear-response approach.Comment: 5 pages, 3 figures, Phys. Rev. Lett., in pres

Right-Wing Moderation, Left-Wing Inertia and Political Cartelisation in Post-Transition Chile

By examining the Manifesto Project data for post-transition Chile, we show growing convergence in the electoral competition strategies between the centre-left and centre-right coalitions. While the former is characterised by inertia, the latter is marked by gradual yet relentless programmatic moderation. To interpret these results, we rely not only on theories of salience and party adaptation, but also on the cartel party thesis. This contribution reinforces the findings of increasing literature on post-transition Chile that reveals growing collusion between the mainstream left-wing and right-wing coalitions, which have increasing difficulties channelling demands emanating from below and therefore providing adequate political representation.A través de un análisis de los datos del Proyecto Manifiesto sobre Chile en la post-transición, mostramos que hay una creciente convergencia en las estrategias electorales entre las coaliciones de centro-izquierda y de centro-derecha. Mientras que la primera se caracteriza por tener cierta inercia, la otra está marcada por una gradual, aunque persistente, moderación programática. Para interpretar estos resultados, nos apoyamos no sólo en teorías sobre la relevancia y adaptación partidarias, sino también en las tesis del partido-cartel. Nuestra contribución refuerza los hallazgos de una creciente literatura sobre la post-transición en Chile que revela una mayor colusión entre las coaliciones de izquierda y de derecha, las que han tenido cada vez más dificultades en canalizar las demandas emanadas desde abajo y por lo tanto en proveer una adecuada representación política.Ao examinar os dados do Projeto Manifesto no Chile pós-transicional, mostramos uma crescente convergência nas estratégias de competição eleitoral entre as alianças da centro-esquerda e da centro-direita. Enquanto a primeira se caracterizou pela inércia, a segunda foi marcada por uma gradual e ao mesmo tempo incansável moderação programática. Para interpretar estes resultados, contamos não somente com teorias de saliência e adaptação partidária, mas também na tese de partido-cartel. Este artigo reforça as descobertas das emergentes publicações sobre o Chile pós-transicional que revela um gradativo embate entre as alianças tradicionais de esquerda e de direita, sendo que essas têm encontrado crescente dificuldade em canalizar as demandas oriundas de baixo, providenciando representação política adequada.Introduction Theoretical Framework The MARPOR Project and its Application to Chile The Evolution of Political Competition in Post-Transition Chile The Dimensions of Electoral Convergence in Post-Transition Chile Cartelisation and Issue Competition in Post-Transition Chile Concluding Remarks Reference

Medición continua del transporte e fondo en un río de gravas: La Tordera

[Resumen] Se ha instalado una estación automática para el control del transporte de fondo en un río de gravas. La estación está compuesta por dos trampas con un sistema de presión sobre un cojín (tipo Birbeck) que permite la obtención de un registro continuo de carga de fondo. En el artículo se muestra el funcionamiento del sistema, su calibración y los primeros resultados obtenidos. Es la primera vez que se obtiene un registro continuo del transporte de fondo en un río de la Península Ibérica.[Abstract] An automatic station for monitoring bedload transport has been installed in a gravel-bed river. The station has two slot samplers with the pressure-pillow system (Birbeck-type) that allow a continuous measurement of bedload transport. The paper shows the bedload sampler operation, the load tests and the first results obtained. It is the first time that bedload transport is registered continuously in a river of the Iberian Peninsula

Ionization states of metallic elements in a quiescent prominence

Inthe frame of the Joint Observing Program 133, which was run during the 6th MEDOC Campaign, a quiet prominence was observed on the 1st of November 2000, between17:30-20:00 UT. From the data we obtained, we want to characterize the emission line profiles and to study the different ionization states of many chemical elements present in the cool plasma of the observed prominence. We also intend to analyze the macroscopic velocities of the material and compare the results with theoretical calculations