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Inner Area (inner + area)
Selected AbstractsMorphometry and composition of aragonite and vaterite otoliths of deformed laboratory reared juvenile herring from two populationsJOURNAL OF FISH BIOLOGY, Issue 6 2003J. Tomás Vaterite otoliths were sampled from two reared populations (Celtic and Clyde Seas) of juvenile herring Clupea harengus. The crystallography, elemental composition and morphometry were analysed and compared with those of normal aragonite otoliths. The incidence of vaterite otoliths in the juveniles sampled (n = 601) ranged from 7·8% in the Clyde population to 13·9% in the Celtic Sea population, and was 5·5% in the small sample (n = 36) of wild adults examined. In all but one case fish had only one vaterite otolith; the corresponding otolith of the pair was completely aragonite. Although the majority of the juveniles sampled showed craniofacial deformities, there was no link between the skull or jaw malformation and the incidence of vaterite otoliths. All vaterite otoliths had an aragonite inner area, and vaterite deposition began sometime after the age of 90 days. The vaterite otoliths were larger and lighter than their corresponding aragonite partners, and were less dense as a consequence of the vaterite crystal structure. The vaterite areas of the otoliths were depleted in Sr, Na and K. Concentrations of Mn were higher in the vaterite areas. The transition between the aragonite inner areas and the vaterite areas was sharply delineated. Within a small spatial scale (20 ,m3) in the vaterite areas, however, there was co-precipitation of both vaterite and aragonite. The composition of the aragonite cores in the vaterite otoliths was the same as in the cores of the normal aragonite otoliths indicating that the composition of the aragonite cores did not seed the shift to vaterite. Vaterite is less dense than aragonite, yet the concentrations of Ca analysed with wavelength-dispersive spectrometry (WDS) were the same between the two polymorphs, indicating that Ca concentrations measured with WDS are not a good indicator of hypermineralized zones with high mineral density. The asymmetry in density and size of the otoliths may cause disruptions of hearing and pressure sensitivity for individual fish with one vaterite otolith, however, the presence of vaterite otoliths did not seem to affect the growth of these laboratory reared juvenile herring. [source] Surface-enhanced Raman scattering from analytes adsorbed on gold nanoparticles inside polymer beadsJOURNAL OF RAMAN SPECTROSCOPY, Issue 10 2004Mina Larsson Abstract Porous polymer beads with a large inner area were used as a stabilizing matrix for SERS-active gold particles. A commercially available ion exchanger (SOURCETM) was used together with HAuCl4. Absorbance measurements and an x-ray diffraction study confirmed that nanocrystalline gold was obtained in the polymer beads. Transmission electron microscope measurements were performed and showed that larger nanoparticles, 20,100 nm, were obtained on the surface, whereas in the interior smaller particles, approximately 2,10 nm, could be found. Three analytes, mercaptoethanesulfonate, mercaptopropionic acid and thiocyanate, were adsorbed on the gold particles inside the polymer beads. From all analytes enhanced Raman spectra could be obtained. The distribution of analytes adsorbed on gold nanoparticles was investigated by confocal Raman spectroscopy. SERS spectra from the analytes could be observed throughout the polymer bead, indicating a fairly uniform distribution of analytes adsorbed on gold nanoparticles. Copyright © 2004 John Wiley & Sons, Ltd. [source] Particulate Matter in the Ross Sea: a Spreading ModelMARINE ECOLOGY, Issue 2002Sergio Tucci Abstract. Within the framework of the C.L.I.M.A. Project, a part of the Italian Research Program in Antarctica, the Total Particulate Matter (TPM) was used as a natural marker to characterise the water masses. The dynamics of TPM was estimated by using a numerical model capable of following the evolution of the basin during the ice absence in summer. The first numerical simulation, with horizontally constant initial conditions and the absence of TPM source areas, merely reveals how TPM passive dispersion is strongly influenced by the Ross Ice Shelf and bathymetry. The second simulation, with TPM concentration horizontally variable and vertically decreasing layers, shows a dynamic evolution of TPM that is in agreement with experimental data. On the surface, in correspondence with the shelf-break, an out-flowing flux with particulate matter contribution coming from Ross Ice Shelf is recognised. The TPM concentration may be linked to the ice melting due to the Antarctic Surface Water, with production of Shallow Ice Shelf Water. The numerical model produces, near the Drygalski area, two cells with high concentration. This numerical evolution is confirmed by the 1990 data (Spezie et al, 1993) that clearly show these two areas and their correlations with the Drygalski contributions (the inner area) and with the thermo-haline front (the external one). This condition is evident in the 1994-1995 data too (Bu-dillon et al, 1999). In this case the authors observed that the Circumpolar Deep Water penetrates onto the shelf at about 174°E; then, modifying its properties, it follows a southward path for about 200 km. The Antarctic Shelf Front (ASF) separates CDW from the colder shelf water with a high concentration of suspended matter. At the 300-meter level, the diffusion of the particulate matter directed under the RIS, towards the continental shelf, seems to be an important feature. Very high TPM values are also present in the deep water in the area off the Drygalski Glacier; this evolution agrees with the ,400 m data collected during the 1990,1991 cruise (Spezie et al., 1993). [source] 2113: AO imaging in AMDACTA OPHTHALMOLOGICA, Issue 2010N MASSAMBA Purpose Two different systems, adaptive optics scanning laser ophthalmoscope (AOSLO), and Spectral Domain Ophtalmoloscopy (SD-OCT) were used to visualize cones in the outer neurosensory retina overlying soft macular drusen and the surrounding retinal areas. Methods High resolution images were obtained with Adaptive Optics (AO) in addition to complete ophthalmic examination including BCVA on ETDRS chart, biomicroscopic examination, autofluorescence imaging, fluorescein and indocyanine angiographies (HRA2 Heidelberg ,Germany) and SD-OCT. The AO image are then compared with conventional infrared and SD-OCT. Soft macular drusen from 50 patients (age between 65 and 85) visible on the scanning laser ophthalmoscope(SLO) examination were evaluated included in the study Results The soft drusen were visible in AO images as generally round areas delimited by a peripheral low-reflectance line. The highly reflective photoreceptor inner/outer segment junction (IS/OS) can be used as a pattern of photoreceptors integrity in SD-OCT images. In areas where the IS/OS junction is absent on SD-OCT, no cones are visualized in registered AOSLO images. In the inner area of many drusen, hyper reflective spots of a size between 2 and 15 µm were sometimes isolated, sometimes grouped into tight aggregates of 2 to 40 components. Cone photoreceptors were visible in areas between drusen in most AO images, however the mosaic image sharpness was significantly less uniform in these elderly patients than previously observed in younger, healthy retinas. Conclusion This study shows the synergistic nature of these two high-resolution retinal imaging systems The microscopic characteristics of soft drusen on AO imaging suggest some analogy with the anatomopathologic characteristics. AO technology will be a powerful tool to refine their clinical classification [source] Morphometry and composition of aragonite and vaterite otoliths of deformed laboratory reared juvenile herring from two populationsJOURNAL OF FISH BIOLOGY, Issue 6 2003J. Tomás Vaterite otoliths were sampled from two reared populations (Celtic and Clyde Seas) of juvenile herring Clupea harengus. The crystallography, elemental composition and morphometry were analysed and compared with those of normal aragonite otoliths. The incidence of vaterite otoliths in the juveniles sampled (n = 601) ranged from 7·8% in the Clyde population to 13·9% in the Celtic Sea population, and was 5·5% in the small sample (n = 36) of wild adults examined. In all but one case fish had only one vaterite otolith; the corresponding otolith of the pair was completely aragonite. Although the majority of the juveniles sampled showed craniofacial deformities, there was no link between the skull or jaw malformation and the incidence of vaterite otoliths. All vaterite otoliths had an aragonite inner area, and vaterite deposition began sometime after the age of 90 days. The vaterite otoliths were larger and lighter than their corresponding aragonite partners, and were less dense as a consequence of the vaterite crystal structure. The vaterite areas of the otoliths were depleted in Sr, Na and K. Concentrations of Mn were higher in the vaterite areas. The transition between the aragonite inner areas and the vaterite areas was sharply delineated. Within a small spatial scale (20 ,m3) in the vaterite areas, however, there was co-precipitation of both vaterite and aragonite. The composition of the aragonite cores in the vaterite otoliths was the same as in the cores of the normal aragonite otoliths indicating that the composition of the aragonite cores did not seed the shift to vaterite. Vaterite is less dense than aragonite, yet the concentrations of Ca analysed with wavelength-dispersive spectrometry (WDS) were the same between the two polymorphs, indicating that Ca concentrations measured with WDS are not a good indicator of hypermineralized zones with high mineral density. The asymmetry in density and size of the otoliths may cause disruptions of hearing and pressure sensitivity for individual fish with one vaterite otolith, however, the presence of vaterite otoliths did not seem to affect the growth of these laboratory reared juvenile herring. [source] Nucleation and facilitation in salt pans in Mediterranean salt marshesJOURNAL OF VEGETATION SCIENCE, Issue 6 2001A.E. Rubio-Casal Tutin et al. (1992) Abstract. Arthrocnemum macrostachyum is a perennial species acting as a primary colonizer of salt pans in Mediterranean high salt marshes. Salicornia ramosissima, an annual, occurs in salt pans under Arthrocnemum canopies and in open areas. The aim of this study was to analyse, in wild populations and a transplant experiment, how S. ramosissima population dynamics and growth are affected by A. macrostachyum. The environmental conditions within the patches of Arthrocnemum were less stressful than in the open areas, with lower radiation levels and salinity concentrations. In the inner areas of A. macrostachyum patches, density-dependent mortality processes of S. ramosissima seedlings led to low densities of adult individuals with greater morphological development and reproductive success than in open areas. However, at the edges of Arthrocnemum patches facilitation of seedling survival favoured high densities. Environmental stress hindered development, decreased reproduction and premature death. These results are in agreement with the general theory of factors controlling vegetation distribution that biotic interactions dominate in low stress environments, while abiotic interactions dominate under harsher environmental conditions. A. macrostachyum plays an essential role in the succession in these salt pans, facilitating seed production and stimulating nucleation processes in S. ramosissima. [source] Drusen in adaptive optics and SD-OCTACTA OPHTHALMOLOGICA, Issue 2009N MASSAMBA Purpose The study objective was to explore the microscopic structure of soft macular drusen and surrounding retinal areas using an adaptive optics (AO) camera and to compare the findings to those from standard clinical examinations. Methods 18 patients of age between 65 and 85 and presenting soft macular drusen were recruited after aninitial scanning laser ophthalmoscope (SLO) examination. We used an AO flood-illumination system to acquire high-resolution images of selected drusen areas. Every acquisition provided a series of 20 consecutive reflectance images, out of which 10 were numerically averaged to produce an enhanced final image. The resulting AO images were analyzed in comparison with conventional infrared and autofluorescence fundus images and spectral optical coherence tomography scans. Results The soft drusen were visible in AO images as generally round areas delimited by a peripheral low-reflectance line. Hyper reflective spots of size comprised between 2 and 15 ,m were observed in many drusen inner areas. These bright spots were sometimes isolated, sometimes grouped into tight aggregates of 2 to 40 components. Cone photoreceptors were visible in areas between drusen in most AO images. Conclusion The microscopic structures observed in the AO images of soft drusen presents analogies with their described anatomopathologic characteristics, which could not be identified using other in vivo imaging techniques. AO technology could help to refine the clinical classification of macular drusen and obtain deeper insight in their link with the development of different types of advanced AMD. Author Disclosure Information: N. Massamba, None; B. Lamory, Imagine Eyes, G. Soubrane, None. [source] | ||||||||||