Do Littoral Macrophytes Influence Crustacean Zooplankton Distribution?

In a meso-eutrophic reservoir, cladoceran and copepod assemblages were characterised in two sampling sites: One located in the pelagic zone (site 1) and the other in the shallow littoral zone (site 2), the latter colonised by emergent macrophytes. Samples were collected biweekly from June to July 2001 and from May to July 2002 at the two sites. At site 1, crustacean zooplankton samples were obtained by vertical hauls using a Wisconsin type net of 64 mm mesh size. At site 2 several random samples were obtained using a van Dorn bottle. Those samples were pooled together and the total sample was sieved through a 64 mm mesh size. Macrophyte relative abundance for each species was visually estimated. Macrophyte community was composed of Glyceria declinata, Eleocharis palustris and Carex sp. A Mann-Whitney U-test was carried out to test for statistically significant differences between sites, for environmental parameters and crustacean zooplankton species densities. Alona rectangula, Alona costata, Alona quadrangularis and Chydorus sphaericus were only found in littoral samples. Daphnia longispina, Daphnia pulex, Ceriodaphnia pulchella, Bosmina longirostris, Diaphanosoma brachyurum, Copidodiaptomus numidicus, and Acanthocyclops robustus were found at both sites. However, Daphnia and Bosmina densities did not differ significantly between the pelagic and littoral sites. Ceriodaphnia, Diaphanosoma, and C. numidicus densities were significantly higher in the pelagic site, whereas A. robustus densities showed the opposite pattern.En un embalse meso-eutrofico las comunidades de cladóceros y copépodos fueron caracterizadas en dos estaciones de muestreo. Una localizada en la zona pelágica (estación 1) y la otra en la zona litoral (estación 2). Esta última está colonizada por macrofitos emergidos. Los muestreos fueron efectuados quincenalmente de Junio a Julio de 2001 y de Mayo a Julio de 2002 en las dos estaciones. En la estación 1 los muestreos de crustáceos del zooplancton se obtuvieron mediante arrastre vertical utilizando una red tipo Wisconsin de 64 mm de poro. En la estación 2 se realizaron varias muestras aleatorias con una botella tipo van Dorn. Las muestras obtenidas en la estación 2 se juntaron y la muestra total resultante fue filtrada por una red de 64 mm de poro. La abundancia relativa de cada una de las especies de macrófitos fue estimada visualmente. La comunidad de macrófitos está constituida por Glyceria declinata, Eleocharis palustris y Carex sp. Fue realizado el test de U de Mann-Whitney para detectar las diferencias estadísticamente significativas entre las dos estaciones, para los parámetros ambientales y para las densidades de los crustáceos del zooplancton. Alona rectangula, Alona costata, Alona quadrangularis y Chydorus sphaericus se han observado únicamente en los muestreos obtenidos en el litoral. Daphnia longispina, Daphnia pulex, Ceriodaphnia pulchella, Bosmina longirostris, Diaphanosoma brachyurum, Copidodiaptomus numidicus y Acanthocyclops robustus se han encontrado en ambas estaciones, no obstante las densidades de Daphnia y Bosmina no presentan diferencias estadísticamente significativas entre la zona pelágica y la litoral. Las densidades de Ceriodaphnia, Diaphanosoma y C. numidicus fueran significativamente más elevadas en la zona pelágica, mientras que la densidad de A. robustus presentó un patrón opuesto

Structural Optimisation: Biomechanics of the Femur

A preliminary iterative 3D meso-scale structural model of the femur was developed, in which bar and shell elements were used to represent trabecular and cortical bone respectively. The cross-sectional areas of the bar elements and the thickness values of the shell elements were adjusted over successive iterations of the model based on a target strain stimulus, resulting in an optimised construct. The predicted trabecular architecture, and cortical thickness distribution showed good agreement with clinical observations, based on the application of a single leg stance load case during gait. The benefit of using a meso-scale structural approach in comparison to micro or macro-scale continuum approaches to predictive bone modelling was achievement of the symbiotic goals of computational efficiency and structural description of the femur.Comment: Accepted by Engineering and Computational Mechanics (Proceedings of the ICE

Theranostic Fibers for Simultaneous Imaging and Drug Delivery

New methods for creating theranostic systems with simultaneous encapsulation of therapeutic, diagnostic, and targeting agents are much sought after. This work reports for the first time the use of coaxial electrospinning to prepare such systems in the form of core–shell fibers. Eudragit S100 was used to form the shell of the fibers, while the core comprised poly(ethylene oxide) loaded with the magnetic resonance contrast agent Gd(DTPA) (Gd(III) diethylenetriaminepentaacetate hydrate) and indomethacin as a model therapeutic agent. The fibers had linear cylindrical morphologies with clear core–shell structures, as demonstrated by electron microscopy. X-ray diffraction and differential scanning calorimetry proved that both indomethacin and Gd(DTPA) were present in the fibers in the amorphous physical form. This is thought to be a result of intermolecular interactions between the different components, the presence of which was suggested by infrared spectroscopy. In vitro dissolution tests indicated that the fibers could provide targeted release of the active ingredients through a combined mechanism of erosion and diffusion. The proton relaxivities for Gd(DTPA) released from the fibers into tris buffer increased (r1 = 4.79–9.75 s–1 mM–1; r2 = 7.98–14.22 s–1 mM–1) compared with fresh Gd(DTPA) (r1 = 4.13 s–1 mM–1 and r2 = 4.40 s–1 mM–1), which proved that electrospinning has not diminished the contrast properties of the complex. The new systems reported herein thus offer a new platform for delivering therapeutic and imaging agents simultaneously to the colon

Qualidade da água na área urbana do Rio Fervença

A qualidade ecológica do rio Fervença na área urbana de Bragança foi avaliada através do recurso a análises físicas, químicas e microbiológicas da água, complementadas com a caracterização do habitat aquático e ribeirinho e das comunidades de macroinvertebrados presentes ao longo do segmento de rio amostrado. Durante um período de dois anos recolheu-se informação em cinco locais de amostragem situados respectivamente a montante, no interior e a jusante da cidade, que permitiu detectar a existência de perturbações ambientais decorrentes do impacto provocado por fenómenos maioritariamente de origem antrópica. O input de substâncias no curso de água, nomeadamente no seu trajecto urbano, reflectiu-se no aumento substancial do teor em sais dissolvidos e em nutrientes, especialmente compostos azotados e fosfatados. Por outro lado, registou-se uma degradação da galeria ripícola e alteração da morfologia do canal que contribuíram para modificar o funcionamento do sistema aquático. A diminuição da integridade ecológica aparece explícita nos índices determinados para o biota (IBMWP), galeria ripícola (QBR) e qualidade do canal (GQC). A renaturalização dos troços mais artificializados do rio poderá contribuir para evitar o crescimento massivo de algas, actualmente observados durante o período estival, nas zonas lênticas do “corredor verde” do Rio Fervença que afectam negativamente a paisagem urbana e que são directamente influenciados pela menor integridade ecológica do ecossistema aquático e ribeirinho

Trace elements and Pb isotope variations in galena from the onça gold deposit, Mato Grosso, Brazil: fluid mixing from hydrothermal and crustal sources

This study deals with the petrography of sulfídes and quartz veins, Pb isotopes, major and trace elements in galena, microthermometry and Raman spectrometry of fluid inclusions, with the objective of delineating temporal and spatial aspects of the fluid circulation patterns during the origin of the Onça gold deposit, Mato Grosso State, Brazil. The Pb isotope and mineral chemistry data indicate variable sources for the Pb isotopes, major (S and Pb) and trace elements (Sb, Ag, Zn and Se), with increases or decreases of the contents during the growth of the galena crystals. The results suggest that the variation may be due to the contamination of the hydrothermal solution by mixing with components derived from supracrustal host rocks of Pontes e Lacerda metavolcanic-sedimentary sequence. The mineral chemistry and fluids inclusion studies suggest two possible sources for the hydrothermal solutions: (1) deep solutions that originated during the regional metamorphism represented by the Aguapeí metamorphic event where the solutions present aqueous-carbonic composition and Iow salinity. Geologic control of the mineralization is in agreement with this hypothesis because the ore bodies are syntectonic with foliation formed during the Aguapeí event; (2) high contents of base metais indicates a plutonic influence in the origin of the fluids. Geologic controls also are in agreement with this hypothesis because pegmatitic intrusion was synchronous with the mineralizations. The Pb isotope and fluid inclusion relations allows the conclusions that the compositions of the hydrothermal solutes were variable during the emplacement of the quartz veins and the growth of galena crystals. The earlier solutes had hydrocarbons and were more radiogenic, whereas the later solutes had base metais and were less radiogenic. The Onça deposit originated during a metamorphic event by the effect of hydrothermal solutions related to plutonism, and with an important contribution from the host rocks as recorded by the influence of isotope, major and trace element compositions on the growth of ore-forming minerais.Este estudo compreende petrografia de sulfetos e veios de quartzo, elementos traços, maiores e isótopos de Pb em galena, microtermometria e espectrometria Raman em inclusões fluidas com o objetivo de delinear aspectos temporais e espaciais da circulação de fluídos durante a origem do depósito aurífero do Onça, Estado do Mato Grosso. Os resultados de isótopos de Pb e a química mineral indicam uma fonte variável para os isótopos de Pb e para elementos maiores (S e Pb) e elementos traços (Sb, Ag, Zn e Se) com aumentos e diminuições nos seus conteúdos durante o crescimento dos cristais de galena de forma que esta variação pode ser resultado da contaminação da solução hidrotermal pelas rochas supracrustais encaixantes da Seqüência Metavulcano-sedimentar Pontes e Lacerda. A química mineral e o estudo das inclusões fluídas sugerem dois tipos de fontes para as soluções hidrotermais: (1) soluções originadas em profundidade durante o metamorfismo regional representado pelo evento Aguapeí, com soluções aquocarbônicas e de baixa salinidade, hipótese corroborada pela concordância dos corpos de minério com a foliação regional gerada por este evento; (2) altos valores de metais básicos indicam uma influência plutônica na origem dos fluídos. Os isótopos de Pb e os estudos de inclusões fluídas analisadas conjuntamente permitem concluir que a composição das soluções hidrotermais foram variáveis durante o emplacement dos veios de quartzo e o crescimento dos cristais de galena. As soluções iniciais apresentam CR, na sua composição e são mais radiogênicas. As soluções finais apresentam metais básicos em sua composição e são menos radiogênicos. Como conclusão é possível sugerir que o depósito do Onça foi originado durante um evento metamórfico por soluções hidrotermais com influência de plutonismo, com uma importante contribuição das rochas encaixantes na composição isotópica do Pb, nos elementos maiores e traços durante o crescimento dos minerais de minério

NMR conformational study of diamagnetic complexes of some triazatriacetate macrocycles

The conformational properties of the diamagnetic complexes formed by five triazatriacetic macrocyclic ligands with monovalent (alkaline) and divalent (alkaline-earth, Zn2+ and Cd2+) cations have been studied by proton nuclear magnetic resonance spectroscopy (1H NMR) in aqueous solution as a function of pH and temperature. These structurally related triazatriacetic ligands, 1,4,7-triazacyclononane-N,N',N''-triacetic acid (NOTA), 1,4,7-triazacyclodecane-N,N',N''-triacetic acid (DETA), 1,4,8-triazacycloundecane-N,N',N''-triacetic acid (UNTA), 1,5,9-triazacyclododecane-N,N',N''-triacetic acid (DOTRA), and 9,10-benzylidene-1,4,7-triazacyclotridecane-N,N',N''-triacetic acid, (BUNTA) have triazamacrocyclic rings with different sizes and flexibilities, bearing three pendant acetate arms. In the case of the alkaline-earth, Zn2+ and Cd2+ cations, only one complex form (1:1) has been detected for all the ligands studied. In most cases the metal ion is coordinated to all the ligand ring nitrogens and to all or some of the carboxylate groups of the pendant arms, except when a poor fit of the cations into the macrocyclic hole occurs, such as for the Ba2+ complexes of DETA, UNTA and DOTRA and the Ca2+ and Sr2+ complexes of BUNTA. The resonance patterns of the ring proton resonances, determined by the long lifetime of the metal-nitrogen bonds, indicate that the six-membered rings formed upon chelation are conformationally rigid and the five-membered rings are conformationally flexible. The multiplicity of the acetate proton resonances shows that the metal-oxygen bonds are long-lived or short lived depending whether the acetates are bound to nitrogens involved in two ring bridges of equal or unequal sizes.http://www.sciencedirect.com/science/article/B6TG5-3T829PD-1D/1/7651a74d4d83a8b051a5d0b9286244e

An annotated checklist of freshwater copepoda (crustacea, hexanauplia) from continental Ecuador and the Galapagos archipelago

An annotated checklist of the free-living freshwater Copepoda recorded in different regions in Ecuador (including the Amazon, the Andes, the coastal region, and the Galapagos Islands) is here provided. We revised all published records, critically evaluated the validity of each taxon and provided short taxonomic and biogeographical remarks for each one. A total of 27 taxa have been reported, including species and records at the generic level only. The species and taxa identified only up to the generic level belong to five families and 14 genera. The Cyclopoida is the most diverse group with 16 records belonging to species (or identified to the generic level only) and eight genera, followed by the Harpacticoida with six species, one identification to the generic level only, and four genera, and Calanoida with four species belonging to two genera. A total of 18 taxa are recorded for the Andes. Six have been recorded in the Amazon, two are recorded for the coastal region, and six for the Galapagos. One species is shared between the Amazon and the Andes. One species is shared between the coastal region and the Amazon. Seventeen are only reported from the Andes and four are only reported from the Amazon. At the current status of the knowledge, any attempt to analyze and generalize distributional patterns of copepods in Ecuador is premature due to the scarcity of available information, and evidently there is an urgent need for more extensive field collections. A few working hypothesis for future studies are identified

Estudio sobre las propiedades del árido reciclado mixto para la fabricación de hormigón no estructural

El objetivo principal de este trabajo de investigación es estudiar las posibilidades de utilización del árido reciclado mixto para la fabricación de hormigón reciclado en aplicaciones no estructurales. Para llevar a cabo esta tarea, se ha realizado primero un estudio bibliográfico extenso para conocer el estado actual del conocimiento sobre las propiedades del árido reciclado mixto y la normativa internacional asociada. En una segunda parte, se ha realizado la caracterización completa de ocho áridos reciclados mixtos gruesos de distinta calidad, procedentes de tres plantas de tratamiento diferentes, comparándose con las tendencias obtenidas en el estudio bibliográfico. En particular, se ha analizado la composición, la densidad y absorción, la granulometría, el coeficiente de Los Ángeles, el índice de lajas, el contenido de finos, las partículas ligeras y el contenido de sulfatos. Se estudian también las correlaciones que existen entre las diferentes propiedades, con el fin de encontrar criterios de calidad de un árido reciclado mixto para un hormigón reciclado no estructural. A raíz de este estudio experimental, se han determinado las propiedades más restrictivas en el empleo de un árido reciclado mixto, siendo éstas el elevado contenido de sulfatos y la elevada absorción