Behaviour of herring (Clupea harengus L.) towards an approaching autonomous underwater vehicle     

Patel  Ruben; Handegard  Nils Olav; Godo  Olav Rune 《ICES Journal of Marine Science》2004,61(7):1044-1049

  相似文献   

Short-term stock assessment of Loligo gahi at the Falkland Islands: sequential use of stochastic biomass projection and stock depletion models     

Roa-Ureta  Ruben; Arkhipkin  Alexander I. 《ICES Journal of Marine Science》2007,64(1):3-17

  相似文献   

Cosmic rotation and the inertial system     

G. Ruben 《Astrophysics and Space Science》1991,177(1-2):465-470

A second order aberration term is employed for a determination of cosmic rotation from extremely precise relative positions of pairs of quasars. The value derived ( o/Ho<10^–5) corresponds with values derived from fluctuations of cosmic background radiation.  相似文献   

A GIS-based approach to compare economic damages of fluvial flooding in the Neckar River basin under current conditions and future scenarios     

Prütz  Ruben  Månsson  Peter 《Natural Hazards》2021,108(2):1807-1834

Natural Hazards - Fluvial floods can cause significant damages and are expected to increase in magnitude and frequency throughout the twenty-first century due to global warming. Alongside hazard...  相似文献   

3D NIR spectroscopy at subarcsecond resolution     

Ruben J. Diaz  Horacio Dottori  Evencio Mediavilla  Maria Aguero  Damian Mast 《New Astronomy Reviews》2006,49(10-12):547

We present a scientific case approached through high quality 3D NIR spectroscopy performed with CIRPASS, attached to the Gemini South telescope. A binary mass concentration at the nucleus of the galaxy M 83 was suggested by Thatte et al. [A&A 364 (2000) L47] and Mast et al. [BAAA 45 (2002) 98. Astroph#0505264] determined the possible position of the hidden secondary mass concentration with 2D H-alpha kinematics. The preliminary results of the NIR study presented here are based in almost 1500 spectra centered in the wavelength 1.3 μm, with a spectral resolving power of 3200. They allow us to unveil, with 0.36″ (6.4 pc) sampling and subarcsecond resolution, the velocity field in a region of 13″ × 9″ around the optical nucleus. We confirm that the optical nucleus is not located at the most important center of symmetry of the ionized gas velocity field. The largest black hole that could fit to the circular motion in this kinematic center should have a mass not larger than 3 × 10⁶(sin i)⁻¹ M solar masses.  相似文献   

Short-term effects of the prestige oil spill on the peregrine falcon (Falco peregrinus)     

Zuberogoitia I  Martínez JA  Iraeta A  Azkona A  Zabala J  Jiménez B  Merino R  Gómez G 《Marine pollution bulletin》2006,52(10):1176-1181

We have monitored the distribution, population status, breeding success, turnover rate and diet of a Peregrine Falcon population in Bizkaia (North of Spain) since 1997. On the 13th November 2002, the tanker Prestige sunk off La Coruña (NW Spain) causing an oil spill that affected the whole of the Cantabrian Coast and the Southwest of France. The total number of birds affected by the Prestige oil spill was expected to be between 115,000 and 230,000, some of them raptors. The loss of clutches during the incubation period increased significantly and was correlated with the loss of females. Moreover, the turnover rate of the population increased from 21% to 30%. The polycyclic aromatic hydrocarbon concentrations in the eggs, collected from five nests after they were deserted, ranged from 21.20 ng/g to 461.08 ng/g, values which are high enough to cause the death of the embryos and poisoning of adult birds. The effects of pollution reached inland since some inland-breeding falcons prey on shorebirds that use rivers during their migratory flights. As the Prestige oil spill has clearly resulted in increased rates of adult mortality and reduced fertility, we suggest that the environmental authorities urgently undertake measures aimed at protecting the Peregrine Falcon in Bizkaia.  相似文献   

Feeding habits of age-0 striped bass,<Emphasis Type="Italic">Morone saxatilis</Emphasis>, in the mid-Hudson River estuary: Temporal,spatial, and ontogenetic variation     

Rebecca?C.?JordanEmail author  David?V.?Howe  Thomas?P.?Hurst  Francis?Juanes 《Estuaries and Coasts》2003,26(6):1486-1493

We quantified temporal and spatial variability in diets of 950 juvenile (age-0) striped bass in the Hudson River estuary. We used canonical correspondence analysis to assess the roles of temporal and spatial habitat variability in juvenile diet variation. We found that juvenile striped bass diets in the Hudson River were only modestly comparable to diets in other east coast estuaries. Among-year differences (51.4%) and spatial differences (41.9%) were substantially associated with juvenile striped bass diet. We found ontogeny (2.8%) and within-season variation (9.5%) to only weakly associate with diet variation. Our results indicate that an understanding of the temporal and spatial variation within the Hudson River estuary is vital in understanding variation in feeding by resident juvenile fish.  相似文献   

Seasonal and ontogenetic changes of mycosporine-like amino acids in planktonic organisms from an alpine lake     

Tartarotti B  Sommaruga R 《Limnology and oceanography》2006,51(3):1530-1541

We studied the quantitative and qualitative mycosporine-like amino acid (MAA) composition in phytoplankton and the copepod Cyclops abyssorum tatricus from an alpine lake over a 15-month period. Up to eight MAAs were identified in the samples, with shinorine being predominant. The MAAs occurred year round and showed a strong seasonal pattern. Compared with ice-cover periods, concentrations during the summer were on average 3.6 and 3.0 times higher in phytoplankton and C. abyssorum tatricus, respectively. During the summer, the contents of MAAs in phytoplankton decreased with depth, suggesting their photoprotective role. Chlorophyll a-specific concentrations of MAAs in phytoplankton correlated significantly with the incident solar radiation and ultraviolet (UV) water transparency (r(2) ≤ 0.36), however, the strongest relationship was found with water temperature (r(2) = 0.67). In zooplankton, highest contents of MAAs were found in eggs, nauplii, and young copepodids, presumably providing a high level of photoprotection for progeny. Proportions of the dominant MAAs in the copepod showed seasonal and ontogenetic variations, which were consistent with relative changes in the predominant MAA, but not other abundant MAAs, in phytoplankton. Considering a time lag of approximately 1 month between the synthesis and subsequent accumulation of these compounds, MAA concentrations in late copepodid to adult life stages were significantly correlated to those in phytoplankton. Annual patterns in MAAs with high concentrations during periods of elevated environmental stress are consistent with the idea that these compounds play an important role in protecting aquatic organisms against UV damage.  相似文献   

Numerical modeling of the transient hydrogeological response produced by tunnel construction in fractured bedrocks   总被引：10，自引：0，他引：10  

Jorge Molinero  Javier Samper  Rubn Juanes 《Engineering Geology》2002,64(4):369-386

Groundwater inflows into tunnels constructed in fractured bedrocks not only constitute an important factor controlling the rate of advancement in driving the tunnel but may pose potential hazards. Drawdowns caused by tunnel construction may also induce geotechnical and environmental impacts. Here we present a numerical methodology for the dynamic simulation of the hydrogeological transient conditions induced by the tunnel front advance. The methodology is based on the use of a Cauchy boundary condition at the points lying along the tunnel according to which water discharge, Q, is computed as the product of a leakage coefficient, , and the head difference, (H−h), where H is the prescribed head at the tunnel wall and h is the hydraulic head in the fractured rock in the close vicinity of the tunnel. At a given position of the tunnel, is zero until the tunnel reaches such position when it is assigned a positive value. The use of step-wise time functions for allows an efficient and accurate simulation of the transient hydrogeological conditions at and around the tunnel during the excavation process. The methodology has been implemented in TRANMEF-3, a finite element computer code for groundwater flow in 3D fractured media developed at the University of A Coruña, Spain, and has been used to simulate the impact of a tunnel on the groundwater system at the Äspö island (Sweden). This tunnel was constructed to access an underground laboratory for research on radioactive waste disposal. The large amount of available data at this site provides a unique opportunity to test the performance of the numerical model and the proposed methodology for tunnel advance. With just minor calibration, the numerical model is able to reproduce accurately the measurements of inflows into the tunnel at several reaches and hydraulic heads at surface-drilled boreholes. These results obtained at the Äspö site lead us to conclude that accurate predictions of the transient hydrogeological responses induced by tunneling works in fractured bedrocks, can be achieved provided that a sound hydrogeological characterization of large-scale fracture zones is available.  相似文献   

Long term variation in rainfall erosivity in Uruguay: a preliminary Fournier approach     

Carolina Munka  Gabriela Cruz  Ruben Mario Caffera 《GeoJournal》2007,70(4):257-262

In order to explore the consequences of precipitation increase on soil erosion in Uruguay, the monthly Fournier Index (FI) and the annual Modified Fournier Index (MFI) were developed as a preliminary approach, covering consecutive decadal periods from 1931 to 2000. Rainfall data were used from 13 stations distributed all over the country. MFI shows a decrease in the 1940s, an increase during the 1950s, then a little decrease during the 1960s and 1970s and an increase in the 1980s, remaining near these last values during the 1990s. FI behavior in July and October in the last two decades shows a decrease in the Northeast region of the country—the region with highest annual precipitation—and a slight increase over the Southeast—the region with the lowest annual precipitation and the only region with a winter rainfall maximum. For the core months of winter and early spring there is a decline in erosivity in the Northeast, but an increase in the Southeast. January shows erosivity decreasing in the South during the last two decades. In April there is a peak in precipitation variability all across the country. FI shows an early increase during the 1940s in the Northwest, and generally very low values during the 1970s, with the return of high values in the 1990s, especially in the Northern corner. Results pose a challenge in order to improve research on the erosion problem, since the main source of freshwater nationwide remains surface river flow, which is prone to higher turbidity problems in areas of high soil erosion.  相似文献