Automated Analyte Separation by Ion Chromatography Using a Cobot Applied to Geological Reference Materials for Li Isotope Composition     

Marie L. Kuessner  Alkiviadis Gourgiotis  Gerard Manhs  Julien Bouchez  Xu Zhang  Jrme Gaillardet 《Geostandards and Geoanalytical Research》2020,44(1):57-67

The demand for large and reliable data sets on isotopic composition has increased in geochemistry and environmental sciences over recent years. We present an automated ion chromatographic separation method using a robotic pipetting arm, termed ‘ChemCobOne’, to reduce sample separation time. Its performance was tested for lithium isotope separation in geological reference materials using a single‐step separation with HCl (0.2 mol l^?1) and a 2 ml resin volume. This refined lithium purification method does not forfeit precision, accuracy or purity compared with manual sample processing. In addition, a δ⁷Li value for NASS‐6 of 30.99 ± 0.50‰ (2s) (95% CI = 0.14‰, n = 44) was determined and the first δ⁷Li values for the granite rock reference material GS‐N (?0.57 ± 0.25‰ (2s), 95% CI = 0.15‰, n = 15), and for the soil reference material NIST SRM 2709a (?0.37 ± 0.67‰ (2s), 95% CI = 0.15‰, n = 63) are proposed.  相似文献   

Home range,residency and movements of Diplodus sargus and Diplodus vulgaris in a coastal lagoon: Connectivity between nursery and adult habitats     

David Abecasis  Luís BentesKarim Erzini 《Estuarine, Coastal and Shelf Science》2009

Acoustic telemetry and standard tag-recapture were used to determine the home range and residency of juveniles and sub-adults of Diplodus sargus and Diplodus vulgaris in the Ria Formosa (Portugal) coastal lagoon. Maximum time between recaptures for the standard tag-recapture method was 128 days for D. sargus and 30 days for D. vulgaris. The majority of the fish were recaptured in the vicinity of the tagging location. Fish tagged with acoustic transmitters had a maximum period of time between first and last detections of 62 days for D. sargus and 260 days for D. vulgaris. Minimum convex polygons areas ranged between 148?024 m² and 525?930 m² for D. sargus and between 23?786 m² and 42?134 m² for D. vulgaris. Both species presented a high residency index between first and last detections. Two D. sargus tagged with acoustic tags were recaptured by fishermen outside the coastal lagoon at distances of 12 km and 90 km from the tagging position, providing evidence that this species leaves the Ria Formosa during the winter time for the adjacent coastal waters. The results of this study reinforce the importance of Ria Formosa as a nursery for D. sargus and D. vulgaris in the south coast of Portugal.  相似文献   

Accuracy assessment of the National Geodetic Survey’s OPUS-RS utility   总被引：1，自引：1，他引：0  

Charles R. Schwarz  Richard A. Snay  Tomás Soler 《GPS Solutions》2009,13(2):119-132

OPUS-RS is a rapid static form of the National Geodetic Survey’s On-line Positioning User Service (OPUS). Like OPUS, OPUS-RS accepts a user’s GPS tracking data and uses corresponding data from the U.S. Continuously Operating Reference Station (CORS) network to compute the 3-D positional coordinates of the user’s data-collection point called the rover. OPUS-RS uses a new processing engine, called RSGPS, which can generate coordinates with an accuracy of a few centimeters for data sets spanning as little as 15 min of time. OPUS-RS achieves such results by interpolating (or extrapolating) the atmospheric delays, measured at several CORS located within 250 km of the rover, to predict the atmospheric delays experienced at the rover. Consequently, standard errors of computed coordinates depend highly on the local geometry of the CORS network and on the distances between the rover and the local CORS. We introduce a unitless parameter called the interpolative dilution of precision (IDOP) to quantify the local geometry of the CORS network relative to the rover, and we quantify the standard errors of the coordinates, obtained via OPUS-RS, by using functions of the form here α and β are empirically determined constants, and RMSD is the root-mean-square distance between the rover and the individual CORS involved in the OPUS-RS computations. We found that α = 6.7 ± 0.7 cm and β = 0.15 ± 0.03 ppm in the vertical dimension and α = 1.8 ± 0.2 cm and β = 0.05 ± 0.01 ppm in either the east–west or north–south dimension.  相似文献   

Efficient multivariable submarine depth-control system design     

Eduardo Licaga-Castro  Jesús Licaga-Castro  Carlos E. Ugalde-Loo  Eva M. Navarro-Lpez 《Ocean Engineering》2008,35(17-18):1747-1758

An efficient solution for the multivariable submarine control design at low-depth conditions under the influence of wave disturbances is presented. The analysis and control design process is carried out under the framework of individual channel analysis and design (ICAD), which is based on the multivariable structure function (MSF). Classical frequency-domain control techniques based on Bode and Nyquist plots are used. Robustness is stated in terms of gain and phase margins. The closed-loop system includes low-order diagonal controllers facilitating its implementation, assessment, and tuning. ICAD discloses new physical insights of the submarine dynamical behaviour. Previous designs based on diagonal controllers consider the input–output channels defined by pairing the bow hydroplane angle with the depth and the stern hydroplane angle with the pitch angle. The alternative input–output pairing leads to unstable closed-loop systems. This phenomenon is associated with hydroplane reverse control. Here it is shown that MSF-based diagonal controllers can be applied effectively for both sets of channel configurations. Emphasis is placed on satisfying design specifications aiming at maintaining the depth low. The solution presented is more feasible and clearer to apply in practice than those so far reported in the literature.  相似文献   

Schooling behaviour and environmental forcing in relation to anchoveta distribution: An analysis across multiple spatial scales   总被引：7，自引：4，他引：3  

Arnaud Bertrand  Franois Gerlotto  Sophie Bertrand  Mariano Gutirrez  Luis Alza  Andres Chipollini  Erich Díaz  Pepe Espinoza  Jesús Ledesma  Roberto Quesqun  Salvador Peraltilla  Francisco Chavez 《Progress in Oceanography》2008,79(2-4):264

The Peruvian anchovy or anchoveta (Engraulis ringens) supports the highest worldwide fishery landings and varies in space and time over many scales. Here we present the first comprehensive sub-mesocale study of anchoveta distribution in relation to the environment. During November 2004, we conducted a behavioural ecology survey off central Peru and used a series of observational and sampling tools including SST and CO₂ sensors, Niskin bottles, CTD probes, zooplankton sampling, stomach content analysis, echo-sounder, multibeam sonar, and bird observations. The sub-mesoscale survey areas were chosen from mesoscale acoustic surveys. A routine coast-wide (2000 km) acoustic survey performed just after the sub-mesoscale surveys, provided information at an even larger population scale. The availability of nearly concurrent sub-mesoscale, mesoscale and coast-wide information on anchoveta distribution allowed for a unique multi-scale synthesis. At the sub-mesoscale (100s m to km) physical processes (internal waves and frontogenesis) concentrated plankton into patches and determined anchoveta spatial distribution. At the mesoscale (10s km) location relative to the zone of active upwelling (and age of the upwelled water) and the depth of the oxycline had strong impacts on the anchoveta. Finally, over 100s km the size of the productive area, as defined by the upwelled cold coastal waters, was the determining factor. We propose a conceptual view of the relative importance of social behaviour and environmental (biotic and abiotic) processes on the spatial distribution of anchoveta. Our ecological space has two y-axis; one based on self-organization (social behaviour), and the other based on the environmental processes. At scales from the individual (10s cm), to the nucleus (m), social behaviour (e.g. the need to school) drives spatial organization. At scales larger than the school, environmental forces are the main driver of fish distribution. The conceptual ecosystem models presented in this paper may provide the final links needed to develop accurate forecasts of the spatial distribution of anchoveta over multiple scales.  相似文献   

Laminated sediments from the central Peruvian continental slope: A 500 year record of upwelling system productivity, terrestrial runoff and redox conditions   总被引：1，自引：1，他引：0  

A. Sifeddine  D. Gutirrez  L. Ortlieb  H. Boucher  F. Velazco  D. Field  G. Vargas  M. Boussafir  R. Salvatteci  V. Ferreira  M. García  J. Valds  S. Caquineau  M. Mandeng Yogo  F. Cetin  J. Solis  P. Soler  T. Baumgartner 《Progress in Oceanography》2008,79(2-4):190

Sedimentological studies including X-ray digital analyses, mineralogy, inorganic contents, and organic geochemistry on cores of laminated sediments accumulated in the oxygen minimum zone of the central Peruvian margin reveal variable oceanographic and climate conditions during the last 500 yr. Coherent upcore variations in sedimentological and geochemical markers in box cores taken off Pisco (B0405-6) and Callao (B0405-13) indicate that variability in the climate proxies examined has regional significance. Most noteworthy is a large shift in proxies at 1820 AD, as determined by ²¹⁰Pb and ¹⁴C radiometric dating. This shift is characterized by an increase in total organic carbon (TOC) in parallel with an abrupt increase in the enrichment factor for molybdenum Mo indicating a regional intensification of redox conditions, at least at the sediment water interface. In addition there was lower terrestrial input of quartz, feldspar and clays to the margin. Based on these results, we interpret that during several centuries prior to 1820, which corresponds to the little ice age (LIA), the northern Humboldt current region was less productive and experienced higher terrestrial input related to more humid conditions on the continent. These conditions were probably caused by a southward displacement of the inter-tropical convergence zone and the subtropical high pressure cell during the LIA. Since 1870, increases in TOC and terrigenous mineral fluxes suggest an increase of wind-driven upwelling and higher productivity. These conditions continued to intensify during the late 20th century, as shown by instrumental records of wind forcing.  相似文献   

Ubiquitination and carbonylation as markers of oxidative-stress in Ruditapes decussatus.     

Suze Chora  Brian McDonagh  David Sheehan  Mireille Starita-Geribaldi  Michèle Roméo  Maria J Bebianno 《Marine environmental research》2008,66(1):95-97

Environmental pollutants, such as metals, are widespread in aquatic environments and can lead to the formation of reactive oxygen species (ROS). ROS are highly toxic in marine species since they can cause serious reversible and irreversible changes in proteins including ubiquitination and modifications such as carbonylation. This study aimed to confirm the potential of ubiquitination and carbonylation as markers of oxidative stress in the clam Ruditapes decussatus (Veneroida, Veneridae) exposed to cadmium (40 microg/L). After 21 days of exposure clams were dissected into gills and digestive gland. Cytosolic proteins of both tissues were separated by two-dimensional electrophoresis (2-D SDS-PAGE) and analysed by immunobloting. Higher ubiquitination and carbonylation levels were in digestive gland of contaminated organisms. These results confirm the potential of ubiquitination and carbonylation as a sensitive and specific marker of oxidative stress in marine bivalves. In this approach, changes in protein structure provide options for affinity selection of sub-proteomes for 2D SDS-PAGE, simplifying the detection of protein biomarkers using proteomic approach.  相似文献   

Environmental niche of the smut lizard population on a sandy coastal ecosystem of Southeastern Tenerife (Canary Islands)     

Antonio de los Santos  & Juan Pedro de Nicolás 《Marine Ecology》2008,29(S1):2-11

Relationships among environmental patterns and population size of the smut lizard Gallotia galloti galloti Oudart, 1839 (Sauria Lacertidae) were examined in the context of longer time-scale variability on a sandy beach and adjacent environments of Southeastern Tenerife. Seasonal and yearly patterns in the population size were likewise analyzed in relation to climatic and anthropic variables. Six sampling plots (coastal, sweet tabaiba, tuff, lava, sandy lava and crater) were selected following a perpendicular transect to the sandy fringe that extends from the beach toward the volcanic interior. Pitfall trapping was conducted from 1984 to 2005, and capture–mark–recapture technique and the Jolly–Seber method were used to estimate population sizes. The highest population size estimates were shown on the sandy lava plot and the neighboring lava plot, reaching values of about 3500 individuals ha⁻¹ during the spring. The population was active almost the whole year, with seasonal patterns of activity from March to October. Seasonal temperature and population size patterns were correlated but the 'calima' episodes produced some disturbance. Gallotia galloti galloti was one of the most abundant lizards of all the species studied and its population size has not remained stable over the study period, probably because of the absence of predation and competition, and because of human interference and environmental instability.  相似文献   

From platform to basin to swell: orbital control on sedimentary sequences in the Oxfordian, Spain     

André Strasser  Marc Aurell  Beatriz Bádenas  Guillermo Meléndez  Sara Tomás 《地学学报》2005,17(5):407-413

Climatic, oceanographic and ecological changes that control the formation and deposition of sediment in shallow and deep depositional environments commonly occur with periodicities of a few 10 000 years. Consequently, in order to interpret sedimentary sequences in the geological past, high time resolution is required. This is best obtained by cyclostratigraphy. Three sections have been studied in the Oxfordian of north-eastern Spain: one represents a shallow, siliciclastic-carbonate platform with repetitive subaerial exposures, one an intraplatform basin with sponge bioherms, and one a swell where iron ooids and glauconite formed. The platform section displays a well-defined stacking pattern of depositional sequences; the deeper-water sections are well dated by ammonites. The correlation between the three sections is a best-fit solution integrating biostratigraphy, sequence stratigraphy and cyclostratigraphy. It is concluded that the small-scale depositional sequences formed in tune with the 100-ka orbital eccentricity cycle. An additional factor was differential subsidence that ruled basin morphology.  相似文献   

Dynamics of perfect fluid unified dark energy models     

Luís M. G. Beça  Pedro P. Avelino 《Monthly notices of the Royal Astronomical Society》2007,376(3):1169-1172

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