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EYMERIC GOMES CHRISTOPHE DEGUEURCE YANNICK RUEL RUTH DENNIS DOMINIQUE BEGON 《Veterinary radiology & ultrasound》2009,50(4):398-403
Magnetic resonance (MR) images of the brain of four normal cats were reviewed retrospectively to assess the emergence and course of the cranial nerves (CNs). Two-millimeter-thick images were obtained in transverse, sagittal, and dorsal planes using a 1.5 T unit. CN skull foramina, as anatomic landmarks for MR imaging, were identified by computed tomography performed on an isolated cat skull using thin wire within each skull foramen. Thin slice (1 mm slice thickness) images were obtained with a high-resolution bone filter scan protocol. The origins of CNs II, V, VII, and VIII and the group of IX, X, XI, and XII could be identified. The pathway and proximal divisions of CNs V were described. CNs III, IV, and VI were not distinguished from each other but could be seen together in the orbital fissure. CN V was characterized by slight contrast enhancement. 相似文献
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Simulation and quantification of enrichment and retention processes in the southern Benguela upwelling ecosystem 总被引：2，自引：0，他引：2
CHRISTOPHE LETT CLAUDE ROY ANNE LEVASSEUR CARL D. VAN DER LINGEN CHRISTIAN MULLON 《Fisheries Oceanography》2006,15(5):363-372
Important environmental processes for the survival and recruitment of early life stages of pelagic fishes have been synthesized through Bakun's fundamental triad as enrichment, concentration and retention processes (A. Bakun, 1996, Patterns in the Ocean. Ocean Processes and Marine Population Dynamics. San Diego, CA, USA: University of California Sea Grant). This conceptual framework states that from favourable spawning habitats, eggs and larvae would be transported to and/or retained in places where food originating from enrichment areas would be concentrated. We propose a method for quantifying two of the triad processes, enrichment and retention, based on the Lagrangian tracking of particles transported within water velocity fields generated by a three‐dimensional hydrodynamic model. We apply this method to the southern Benguela upwelling ecosystem, constructing putative maps of enrichment and retention. We comment on these maps regarding main features of the circulation in the region, and investigate seasonal variability of the processes. We finally discuss the results in relation to available knowledge on the reproductive strategies of two pelagic clupeoid species abundant in the southern Benguela, anchovy (Engraulis encrasicolus) and sardine (Sardinops sagax). Our approach is intended to be sufficiently generic so as to allow its application to other upwelling systems. 相似文献
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Predicting skipjack tuna forage distributions in the equatorial Pacific using a coupled dynamical bio-geochemical model 总被引：7，自引：0，他引：7
PATRICK LEHODEY JEAN-MICHEL ANDRE MICHEL BERTIGNAC JOHN HAMPTON ANNE STOENS CHRISTOPHE MENKES LAURENT MEMERY & NICOLAS GRIMA 《Fisheries Oceanography》1998,7(3-4):317-325
Skipjack tuna ( Katsuwonus pelamis ) contributes ≈70% of the total tuna catch in the Pacific Ocean. This species occurs in the upper mixed-layer throughout the equatorial region, but the largest catches are taken from the warmpool in the western equatorial Pacific. Analysis of catch and effort data for US purse seine fisheries in the western Pacific has demonstrated that one of the most successful fishing grounds is located in the vicinity of a convergence zone between the warm (>28–29°C) low-salinity water of the warmpool and the cold saline water of equatorial upwelling in the central Pacific (Lehodey et al ., 1997). This zone of convergence, identified by a well-marked salinity front and approximated by the 28.5°C isotherm, oscillates zonally over several thousands of km in correlation with the El Niño–Southern Oscillation. The present study focuses on the prediction of skipjack tuna forage that is expected to be a major factor in explaining the basin-scale distribution of the stock. It could also explain the close relation between displacements of skipjack tuna and the convergence zone on the eastern edge of the warmpool. A simple bio-geochemical model was coupled with a general circulation model, allowing reasonable predictions of new primary production in the equatorial Pacific from mid-1992 to mid-1995. The biological transfer of this production toward tuna forage was simply parameterized according to the food chain length and redistributed by the currents using the circulation model. Tuna forage accumulated in the convergence zone of the horizontal currents, which corresponds to the warmpool/equatorial upwelling boundary. Predicted forage maxima corresponded well with high catch rates. 相似文献
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SABINE C. RIESEN MARCUS G. DOHERR CHRISTOPHE W. LOMBARD 《Veterinary radiology & ultrasound》2007,48(6):570-573
In normal dogs and dogs with subaortic stenosis, it is known that the subcostal transducer site provides higher left ventricular ejection velocities than does the left apical site. We hypothesized that aortic flow velocities could also be obtained from the right parasternal long-axis view, optimized for the placement of the Doppler cursor as parallel as possible into the aortic root. In 15 healthy dogs and 13 healthy cats, high-pulsed repetition frequency Doppler flow velocity measurements in the proximal aorta were performed using two-dimensional echocardiographic guidance. The mean [ +/- standard error of the mean (SEM)] peak aortic flow velocities in healthy dogs were as follows: subcostal site 1.46 +/- 0.05 m/s; apical site 1.12 +/- 0.06 m/s; right parasternal long-axis site 1.09 +/- 0.05 m/s. In healthy cats, the following peak aortic flow velocities were observed: apical site 0.87 +/- 0.03m/s; right parasternal long-axis site 0.87 +/- 0.03 m/s. Aortic flow velocities obtained from the subcostal site were significantly higher in healthy dogs than those obtained from the left apical and right parasternal long-axis site (P< 0.001). There was no statistical difference between the peak aortic flow velocities obtained from right parasternal long-axis and left apical transducer position in all groups. We conclude therefore that right parasternal long-axis and left apical-derived aortic flow velocities are similar and may be used interchangeably in healthy dogs and cats. 相似文献
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CHRISTOPHE LOOTS SANDRINE VAZ BENJAMIN PLANQUE PHILIPPE KOUBBI 《Fisheries Oceanography》2011,20(1):18-31
The processes that control the spatial distribution of North Sea whiting (Merlangius merlangus) spawning adults are investigated using a statistical multi‐model approach. Models of external and internal controls on the population, such as environmental conditions, spatial constraints, present or past spatial distribution, and demographic state of the population, are evaluated, compared and ranked to select those that are the best able to predict the observed distribution of spawning adults. Model selection is greatly influenced by the selection method, either based on data fitting or prediction, as well as by the threshold value used to stop the selection. Model selection based on prediction tends to select simpler models than selection based on data fitting. The hypotheses underlying the selected models are inferred to play a significant role in controlling North Sea whiting spatial distribution. The multi‐model inference approach developed in this study enables comparison of several theoretical concepts and hypotheses and the results provide important clues on the processes involved in the control of the spatial distribution of whiting. We conclude that whiting has a high spatial fidelity to spawning site which can be linked to either geographical attachment or year‐to‐year persistence of the spatial distribution of the population. Environmental factors – temperature and salinity – appear to influence the geographical extent of spawning whiting distribution, whereas local abundance levels are primarily controlled by internal factors, i.e., population size and spatial segregation between ages. 相似文献
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CHRISTOPHE W. LOMBARD 《The Journal of small animal practice》1984,25(2):59-70
The clinical signs, electrocardiograms and echocardiograms of 12 dogs with dilated cardiomyopathy of large breeds and congestive heart failure were reviewed. There was a high prevalence of males (11 dogs) and of the Doberman breed (7 dogs). Seven dogs had atrial fibrillation. The echocardiograms revealed significant increases in left ventricular and left atrial dimensions. The shortening fraction (%ΔD), aortic root excursion and left ventricular wall excursion were all significantly decreased, documenting a decrease in contractile function of the left ventricle that, together with the cardiac enlargement characterize this disease. The advantages of obtaining these functional parameters non-invasively are emphasized. 相似文献
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