Better Understanding Of Possible Effects Research Articles

The International Association of Geomorphologists (IAG) Working Group on Denudation and Environmental Changes in Different Morphoclimatic Zones (DENUCHANGE): Scientific need, research objective, key activities and products

Denudation, including both chemical and mechanical processes, is of high relevance for Earth surface and landscape development and the transfer of solutes and sediments from headwater systems through main stem of drainage basin systems to the world oceans. The better understanding of possible effects of ongoing and accelerated environmental changes on present-day denudation requires systematic and quantitative studies on the actual drivers of denudational processes in differentiated landscape controls. Only if we have an improved knowledge of drivers, mechanisms and rates of contemporary denudational processes across a range of different selected climatic environments, possible effects of global environmental changes on denudation can be better assessed. However, a systematic geomorphologic comparison of present-day denudation rates in different defined climatic zones combined with a coordinated analysis and compilation of the respective key controls of denudation that is presently occurring in clearly defined drainage basin systems in the different selected morphoclimatic settings is still largely missing. The International Association of Geomorphologists (IAG) Working Group on Denudation and Environmental Changes in Different Morphoclimatic Zones (DENUCHANGE) is since 2017 helping to close this still existing knowledge gap and contributes to a better understanding of the possible effects of global environmental changes on contemporary Earth surface systems.

Degree and Distribution of Mineralization in the Human Mandibular Condyle

The degree of mineralization of bone (DMB) in the mandibular condyle reflects the age and remodeling rate of the bone tissue. Quantification of DMB facilitates a better understanding of possible effects of adaptive remodeling on mineralization of the condyle and its possible consequences for its mechanical quality. We hypothesized differences in the degree and distribution of mineralization between trabecular and cortical bone and between various cortical regions. Microcomputed tomography was used to measure mineralization in 10 human mandibular condyles. Mean DMB was higher in cortical (1,045 mg hydroxyapatite/cm(3)) than in trabecular bone (857 mg/cm(3)) and differed significantly between cortical regions (anterior 987 mg/cm(3), posterior 1,028 mg/cm(3), subchondral 1,120 mg/cm(3)). The variation of DMB distribution was significantly larger in the anterior cortex than in the posterior and subchondral cortex, indicating a larger amount of heterogeneity of mineralization anteriorly. Within the cortical bone, DMB increased with the distance from the cortical canals to the periphery. Similarly, the DMB of trabecular bone increased with the distance from the surface of the trabeculae to their cores. It was concluded that the rate of remodeling differs between condylar trabecular and cortical bone and between cortical regions and that DMB is not randomly distributed across the bone. The difference in DMB between condylar cortical and trabecular bone suggests a large difference in Young's modulus.