Usefulness of microsatellite markers developed from Pagellus bogaraveo to genetically study five different species of Sparidae     

Jorge A. Piñera  David Bernardo  Gloria Blanco  Emilia Vázquez  & José A. Sánchez 《Marine Ecology》2007,28(S1):184-187

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Species and size selectivity in a Portuguese multispecies artisanal long-line fishery   总被引：1，自引：0，他引：1  

Erzini  Karim; Goncalves  Jorge M. S.; Bentes  Luis; Lino  Pedro G.; Cruz  Joao 《ICES Journal of Marine Science》1996,53(5):811-819

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Feeding ecology of cod (Gadus morhua L.) in Balsfjord and Ullsfjord, northern Norway, 1982-1983     

Santos  Jorge dos; Falk-Petersen  Stig 《ICES Journal of Marine Science》1989,45(2):190-199

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The simultaneous analysis of total nitrogen and total phosphorus in natural waters   总被引：1，自引：0，他引：1  

Jorge C. Valderrama 《Marine Chemistry》1981,10(2):109-122

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Possibilities of discriminating tropical secondary succession in Amazônia using hyperspectral and multiangular CHRIS/PROBA data     

Lênio Soares Galvão  Flávio Jorge PonzoniVeraldo Liesenberg  João Roberto dos Santos 《International Journal of Applied Earth Observation and Geoinformation》2009

CHRIS/PROBA data collected in the Brazilian Amazônia in 4 view angles (−36°, nadir, +36°, +55°) and 62 bands (410–1000 nm range) were evaluated for the discrimination between primary forest and 3 stages of secondary succession after deforestation: initial (SS1; <5 years), intermediate (SS2; 5–15 years) and advanced (SS3; >15 years). Single view angle and multiangular approaches (nadir plus anisotropic information derived from reflectance ratios between view angles) were tested for discrimination. Both approaches used principal components analysis (PCA) applied to pixel spectra representative of each class in order to reduce data dimensionality at each dataset, to enhance separability between the classes, and to provide input variables for multiple discriminant analysis (MDA). The results showed that the off-nadir viewing improved discrimination between the successional stages. Discrimination between SS2 and SS3 was enhanced with PCA at +36° view angle. Primary forest and SS3 presented a more anisotropic behavior than SS2 and SS1, especially in the backward scattering direction (positive view angles) in which great amounts of sunlit canopy components were viewed by the sensor. MDA classification results showed that the multiangular approach produced an overall improvement in the discrimination. From the single (nadir) to the multiangular approach, classification accuracy using a separate set of pixels increased from 83.3% to 98.3% for SS1, 53.3% to 70.0% for SS2, and 58.3% to 76.7% for SS3. The nadir and multiangular classifications were statistically different at a 0.05% level of significance. Kappa statistics increased from 0.63 to 0.82. The results showed that multiangular data can improve the differentiation between primary forest and old stages of natural vegetation regrowth, which have been reported in the literature as the most difficult classes to be mapped in the Amazonian environment.  相似文献   

Continuation of normal doubly symmetric orbits in conservative reversible systems   总被引：1，自引：1，他引：0  

Francisco Javier Muñoz-Almaraz  Emilio Freire  Jorge Galan-Vioque  Andre Vanderbauwhede 《Celestial Mechanics and Dynamical Astronomy》2007,97(1):17-47

In this paper we introduce the concept of a quasi-submersive mapping between two finite-dimensional spaces, we obtain the main properties of such mappings, and we introduce “normality conditions” under which a particular class of so-called “constrained mappings” are quasi-submersive at their zeros. Our main application is concerned with the continuation properties of normal doubly symmetric orbits in time-reversible systems with one or more first integrals. As examples we study the continuation of the figure-eight and the supereight choreographies in the N-body problem.  相似文献   

Long-term changes in fish communities of the Ria Formosa coastal lagoon (southern Portugal) based on two studies made 20 years apart     

Joaquim Ribeiro  Carlos C. Monteiro  Pedro Monteiro  Luis Bentes  Rui Coelho  Jorge M.S. Gonçalves  Pedro G. Lino  Karim Erzini 《Estuarine, Coastal and Shelf Science》2008

Fish communities of the Ria Formosa coastal lagoon (south Portugal) were sampled on a monthly basis with a beach seine at 4 sites, during two different time periods: 1980–1986 and 2001–2002. Community indices, species ranking and multivariate analysis were used in order to identify changes in the fish community between the two time periods. A total of 153,511 fish representing 57 taxa were recorded. Although species composition was very similar for both sampling periods, multivariate analysis performed on annual species abundance in number and weight revealed differences in fish community structure between the two periods. Structural changes in fish community were related mostly to a sharp decrease in the abundance of Mugilidae from 1980–1986 to 2001–2002. These changes were probably associated to a decrease in organic matter contents and nutrients concentrations due to improvements in sewage treatment and better water circulation inside the lagoon. The changes in fish community structure are more evident in the inner areas of the lagoon than near the inlet. The association between changes in sewage patterns and changes in the ichthyofaunal community structure reinforces the importance of fish communities as a biological indicator of human induced changes in marine systems.  相似文献   

250 years of sardine and anchovy scale deposition record in Mejillones Bay, northern Chile   总被引：2，自引：1，他引：1  

Jorge Valds  Luc Ortlieb  Dimitri Gutierrez  Luis Marinovic  Gabriel Vargas  Abdel Sifeddine 《Progress in Oceanography》2008,79(2-4):198

Marine oxygen-deficient environments with high sedimentation rates and high primary productivity can provide relevant information regarding variations of ocean–climatic conditions in the past. In the Humboldt current ecosystem, which now hosts huge populations of pelagic fishes (mainly anchovy and sardine), fish scale abundance in the sedimentary record may be useful indicators of environmental change. Here we assess such a proxy record in a 42 cm-long sedimentary core collected from 80 m in Mejillones Bay (23°S, northern Chile). We also analyse fish remains in surface sediment sampled along a bathymetric transect (from 10 to 110 m water depth) in the same bay. In the core-top record, the fluctuations of sardine and anchovy scale deposition rates (SDR) agreed with those of industrial catches for these two species in northern Chile, tending to validate the SDR as a proxy of local fish biomass when bottom anoxic conditions prevail. However, apparent SDR for records prior to 1820 have probably been influenced by dissolution processes linked to the oxygenation of the bottom environment of Mejillones Bay, as suggested by other proxy records. After 1820, the fluctuations in the relative abundance of sardine and anchovy scales point to alternating warm and cold conditions during about 30 years and then a progressively cooler period. Since ca. 1870, marked fluctuations of SDR of both species are observed, probably as a consequence of the onset of a different oceanographic regime characterized by intensified upwelling, stronger subsurface oxygen deficiency, higher primary productivity, and enhanced “ENSO-like” interdecadal variability. While anchovy SDR fluctuated in periods of 25–40 years, only two peak periods of sardine SDR occurred (late 19th century and late 20th century), suggesting that sardine abundance depends on other ocean–climatic factors.  相似文献   

Characterizing sources of groundwater to a tropical coastal lagoon in a karstic area using radium isotopes and water chemistry   总被引：2，自引：1，他引：1  

Megan B. Young  Meagan Eagle Gonneea  Derek A. Fong  Willard S. Moore  Jorge Herrera-Silveira  Adina Paytan   《Marine Chemistry》2008,109(3-4):377

Radium isotopes (²²³Ra, ²²⁴Ra, ²²⁶Ra, and ²²⁸Ra) and water chemistry were used to identify two chemically distinct sources of submarine groundwater discharge (SGD) in Celestún Lagoon, Yucatán, Mexico. Low salinity groundwater discharging from springs within the lagoon has previously been identified and extensively sampled for nutrient concentrations. However, a second type of groundwater discharging into the lagoon was detected during this study using radium isotope activity measurements. This second type of groundwater is characterized by moderate salinities (within the range of lagoon salinities) and very elevated radium activities in comparison to the low salinity groundwater, mixed lagoon water, and seawater. Further analysis showed that the two types of groundwater also have distinct chloride, strontium, and sulfate ratios, along with slightly different nutrient concentrations. Groundwater discharge occurs through large and small springs scattered throughout the lagoon, and both types of groundwater were detected discharging from one of the larger springs. The relative proportions of low salinity groundwater and brackish high radium groundwater varied over the tidal cycle. In order to better understand the relative contributions of each type of groundwater to the lagoon, a three end-member mixing model based on the distinct chemical and isotopic compositions of both types of groundwater and of seawater was used to estimate the distribution of each water type throughout the lagoon in different seasons. This study suggests that substantial groundwater discharge to the lagoon can occur during both dry and rainy seasons. The presence of two groundwater sources has implications for monitoring and protection of the Celestún Lagoon Biosphere Reserve, since the two sources may have different susceptibilities to anthropogenic contamination depending on their respective recharge area and recharge rates.  相似文献   

A comparison of the Iberian and Ebro Basins during the Permian and Triassic, eastern Spain: A quantitative subsidence modelling approach   总被引：2，自引：0，他引：2  

Henar Vargas  Jorge M. Gaspar-Escribano  Jos Lpez-Gmez  Jan-Diederik Van Wees  Sierd Cloetingh  Raúl de La Horra  Alfredo Arche 《Tectonophysics》2009,474(1-2):160

The Permian–Triassic sediments of the Iberian Plate are a well studied case of classical Buntsandstein–Muschelkalk–Keuper facies, with good sedimentological interpretations and precise datings based on pollen and spore assemblages, ammonoids and foraminifera. Synrift–postrift cycles are recorded in these facies, but there are only a few studies of quantitative subsidence analysis (backstripping method) and only a previous one using forward modelling for the quantification of synrift–postrift phases of this period.Here we present the results obtained by the quantitative analysis of fourteen field sections and oil-well electric log records in the Iberian and Ebro Basins, Spain. Backstripping analysis showed five synrift phases of 1 to 3 million years duration followed by postrift periods for the Permian–Triassic interval. The duration, however, shows lateral variations and some of them are absent in the Ebro Basin. The forward modelling analysis, assuming local isostatic compensation, has been applied to each observation point using one-layer and two-layer lithospheric configurations. The second one shows a better fit between observation and model prediction in a systematic way, so a two layer configuration is assumed for the sedimentary basin filling analysis. Lithospheric stretching factors β and δ obtained in the forward modelling analysis are never higher than 1.2, but sometimes β < 1 and simultaneously δ > 1 in the same section. If surficial extension is compensated by deep compression either at the roots of the rift basins or in far-away zones is not yet clear, but this anomaly can be explained using a simple shear extensional model for the Iberian and Ebro basins.  相似文献