Search Results - (Author, Cooperation:J. P. Roux)

2011-12-24

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Biomass ; Birds/*physiology ; Charadriiformes/*physiology ; *Ecosystem ; Female ; Fisheries ; *Fishes ; Food ; Food Chain ; Male ; Nonlinear Dynamics ; Population Density ; Population Dynamics ; Predatory Behavior ; *Reproduction ; Seawater ; Statistics, Nonparametric

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-3091

Blackwell Publishing Journal Backfiles 1879-2005

Geosciences

Electronic Resource

0040-4020

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0047-2670

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0040-4039

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0570-5398

Linguistics and Literary Studies

Ethnic Sciences

History

Theology and Religious Studies

Bulletin critique

1433-2965

Key words:High-resolution computed tomography – Histomorphometry – Human cancellous bone – Mechanical properties

Springer Online Journal Archives 1860-2000

Medicine

Abstract: The aim of the present study on human vertebral cancellous bone was to validate structural parameters measured with high-resolution (150 μm) computed tomography (HRCT) by referring to histomorphometry and to try to predict mechanical properties of bone using HRCT. Two adjacent vertical cores were removed from the central part of human L2 vertebral body taken after necropsy in 22 subjects aged 47–95 years (10 women, 12 men; mean age 79 ± 14 years). The right core was used for structural analysis performed by both HRCT and histomorphometry. Two cancellous bone specimens were extracted from the left core: a cube for HRCT and a compression test, and a cylinder for a shear test. Significant correlations were found between HRCT and histomorphometric measurements (BV/TV, trabecular thickness, separation and number, and node-strut analysis), but with higher values for most of the tomographic parameters (BV/TV and trabecular thickness determined by HRCT were overestimated by a factor 3.5 and 2.5 respectively, as compared with histomorphometry). The maximum compressive strength and Young’s modulus were highly correlated (ρ= 0.99, p〈0.0005). Significant correlation was obtained between bone mineral density (determined using dual-energy X-ray absorptiometry) and the maximum compressive strength (ρ= 0.64, p= 0.002). In addition the maximum compressive strength and architectural parameters determined by HRCT or histomorphometry showed significant correlations (e.g., for HRCT, BV/TV: ρ = 0.88, p〈0.0005, N.Nd/TV: ρ= 0.73, p〈0.001). The shear strength was significantly correlated with BV/TV (ρ= 0.62, p= 0.002), Tb.Sp (ρ=−0.58, p= 0.004) and TSL (ρ= 0.55, p= 0.006) measured by HRCT. In conclusion, an HRCT system with 150 μm resolution is not sufficient to predict the true values of the structural parameters measured by histomorphometry, although high correlations were found between the two methods. However, we showed that a resolution of 150 μm allowed us to predict the mechanical properties of human cancellous bone. In vivo peripheral systems with such a resolution should be of interest and would deliver an acceptable radiation dose to the patient.

Electronic Resource

1437-3262

Cape orogeny ; Karoo Basin ; Gondwanaland ; Paroxysm ; Sedimentation rates

Springer Online Journal Archives 1860-2000

Geosciences

Abstract Careful consideration of the effects of the Cape orogeny on sedimentation in the Carboniferous-Jurassic Karoo Basin provides an indirect tool for accurately dating these rocks. Fossil and radiometric data, especially when combined with sedimentological and structural information, yield partly overlapping age brackets which can be used to correlate the successive tectonic pulses with specific depositional events. Application of these principles to associated basins in Gondwanaland can provide a firm foundation for more dependable stratigraphic correlation on a global scale. The exercise also suggests that a number of widely held opinions on the age of certain stratigraphic units in the Karoo Supergroup may be incorrect.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] A NEW species of albatross has been discovered on Amsterdam Island, situated in the southern Indian Ocean midway between South Africa and Australia, and named Amsterdam Albatross, Diomedea amsterdamensis. Several 'great albatrosses', presumed to belong to the species Diomedea exulans (Wandering ...

Electronic Resource

0570-5398

Linguistics and Literary Studies

Ethnic Sciences

History

Theology and Religious Studies

Bulletin Critique

1432-0827

Key words: Fractal analysis—Os calcis—Radiographs—Histomorphometry—Microarchitecture.

Springer Online Journal Archives 1860-2000

Biology

Medicine

Physics

Abstract. Microarchitecture of trabecular bone is an important determinant of bone fragility; to date, its evaluation requires bone biopsy with histomorphometry analysis. Methods of noninvasive characterization of trabecular bone microarchitecture are in development and we have developed and validated a bone texture analysis applied to bone radiographs and based on fractal geometry. The aim of our study was to compare this fractal analysis of trabecular bone texture on radiographs to the trabecular microarchitecture analyzed by bone histomorphometry on os calcis biopsies. Thirty eight ossa calcis from 19 human cadavers were studied. Fractal analysis of the trabecular bone of os calcis radiographs was performed by the maximum likelihood estimator following the fractional brownian motion model. The ossa calcis were dissected, then transcortical biopsy cores focused on the fractal analysis region of interest were obtained. Structural and connectivity parameters were measured with both automatic and semiautomatic analyzers. We have found a significant relationship between the fractal Hmean parameter and structural histomorphometric indices; the best correlation was found with trabecular separation (r =−0.55; P= 0.0004). Based on a stepwise regression analysis, trabecular spacing and trabeculae number together would explain 38% of the variance of the fractal parameter. Although the relationship with connectivity indices was poor, our fractal analysis of os calcis trabecular bone texture on radiographs seemed to partially reflect the trabecular bone microarchitecture.

Electronic Resource

1618-2650

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Summary The initial stages of oxidation of clean (110), (100), and (111) oriented β-NiAl single crystals, with and without Pt doping (50 nm), were followed at 973 K using LEED and AES. Upon oxidation, Al2O3 is selectively formed. On NiAl (110) a complex surface structure is observed which according to Jäger et al. [13] is a duplex oxide structure similar to α- or γ-Al2O3. On the (100) face, submicroscopic facetting occurs during oxidation. For the (111) oriented sample the hexagonal structure remains and only an increased background intensity for the LEED pattern is observed for the oxidized surface. After Pt doping, the phenomena observed for the Pt-free sample are not significantly changed. However the following differences exist: 1. the formation of the Al2O3 oxide is more difficult for the (110) and (111) samples but Pt doping facilitates facetting and oxide formation on the (100) oriented sample; 2. sputtering of the oxide layers on Pt-doped samples is retarded in all cases, a very stable and dense oxide seems to be formed which adheres well; 3. Pt seems to hinder the Al diffusion to the unoxidized surface of the samples.

Electronic Resource

0016-7835

Key words Cape orogeny ; Karoo Basin ; Gondwanaland ; Paroxysm ; Sedimentation rates

Springer Online Journal Archives 1860-2000

Geosciences

Abstract  Careful consideration of the effects of the Cape orogeny on sedimentation in the Carboniferous–Jurassic Karoo Basin provides an indirect tool for accurately dating these rocks. Fossil and radiometric data, especially when combined with sedimentological and structural information, yield partly overlapping age brackets which can be used to correlate the successive tectonic pulses with specific depositional events. Application of these principles to associated basins in Gondwanaland can provide a firm foundation for more dependable stratigraphic correlation on a global scale. The exercise also suggests that a number of widely held opinions on the age of certain stratigraphic units in the Karoo Supergroup may be incorrect.

Electronic Resource

0006-3592

Chemistry ; Biochemistry and Biotechnology

Wiley InterScience Backfile Collection 1832-2000

Biology

Process Engineering, Biotechnology, Nutrition Technology

One important economical method for producing singlecell protein is to spray dry the cultured cells. This study presents some preliminary data on the effects of spray drying on cell viability. Under conditions similar to those for the production of spray-dried milk, 4-5 log cycles destruction occurred. The results indicate that, the activation energy for thermal destruction of yeast was reduced from the normal heat treatment value of 84 kcal/°K mole to about 38 kcal/°K mole.

1 Ill.

Electronic Resource

1618-2650

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Summary The oxidation of NiAl at 950°C was studied for samples having the three different orientations (111), (100), and (110) both undoped and superficially doped with Pt. Differences in oxidation rates and scale morphology were observed during the first 100 h of scale growth depending on orientation and Pt doping; these are caused by differences in nucleation and the Θ- to α-Al2O3 transformation. No distinct, positive ‘precious element’ effect was exerted by the presence of Pt; a retardation of the Θ - to α-transformation and a decrease of metal-oxide coherence were noted however.

Electronic Resource