Landscape characterization and biodiversity research

Rapid deforestation often produces landscape-level changes in forest characteristics and structure, including area, distribution, and forest habitat types. Changes in landscape pattern through fragmentation or aggregation of natural habitats can alter patterns of abundance for single species and entire communities. Examples of single-species effects include increased predation along the forest edge, the decline in the number of species with poor dispersal mechanisms, and the spread of exotic species that have deleterious effects (e.g., gypsy moth). A decrease in the size and number of natural habitat patches increases the probability of local extirpation and loss of diversity of native species, whereas a decline in connectivity between habitat patches can negatively affect species persistence. Thus, there is empirical justification for managing entire landscapes, not just individual habitat types, in order to insure that native plant and animal diversity is maintained. A landscape is defined as an area composed of a mosaic of interacting ecosystems, or patches, with the heterogeneity among the patches significantly affecting biotic and abiotic processes in the landscape. Patches comprising a landscape are usually composed of discrete areas of relatively homogeneous environmental conditions and must be defined in terms of the organisms of interest. A large body of theoretical work in landscape ecology has provided a wealth of methods for quantifying spatial characteristics of landscapes. Recent advances in remote sensing and geographic information systems allow these methods to be applied over large areas. The objectives of this paper are to present a brief overview of common measures of landscape characteristics, to explore the new technology available for their calculation, to provide examples of their application, and to call attention to the need for collection of spatially-explicit field data

Martensitic transformation of individual grains in low-alloyed TRIP steels

We have performed in situ synchrotron X-ray diffraction experiments on low-alloyed multiphase TRIP steels during cooling, to monitor the martensitic transformation of individual austenite grains within the bulk material. Direct experimental evidence is presented that the stability of the austenite grains is controlled not only by the local carbon level but also by the grain size. This new quantitative information on the martensitic transformation in complex microstructures is of great importance for the design of martensite-based metallic materials.</p

Characterization of individual retained austenite grains and their stability in low-alloyed TRIP steels

In situ three-dimensional (3-D) X-ray diffraction experiments have been performed at a synchrotron source on low-alloyed multiphase TRIP steels containing 0.25 wt.% Si and 0.44 wt.% Al and produced with different bainitic holding times, in order to assess the influence of the bainitic transformation on the thermal stability of individual austenite grains with respect to their martensitic transformation. A detailed characterization of the austenite grain volume distribution at room temperature was performed as a function of the prior bainitic holding time. In addition, the martensitic transformation behaviour of individual metastable grains was studied in situ during cooling to a temperature of 100 K. Both the carbon content and the grain volume play a key role in the stability of the austenite grains below 15 μm3, while the carbon content exerts the dominant effect in the stability of the bigger grains. Measurements also suggest that the tetragonality of the thermally formed martensite is suppressed.</p

Competition for vs. on the rails: a laboratory experiment

Abstract Several European countries and Japan are in various stage

Mouse models of cystic fibrosis: Phenotypic analysis and research applications

AbstractGenetically modified mice have been studied for more than fifteen years as models of cystic fibrosis (CF). The large amount of experimental data generated illuminates the complex multi-organ pathology of CF and raises new questions relevant to human disease. CF mice have also been used to test experimental therapies prior to clinical trials. This review recapitulates the major phenotypic traits of CF mice and highlights important new findings including aberrant alveolar macrophages, bone and cartilage abnormalities and abnormal bioactive lipid metabolism. Novel data are presented on the intestinal and nasal physiology of F508del-CFTR CF mice backcrossed onto different genetic backgrounds. Caveats, and sources of variability including age, gender and animal husbandry, are discussed. Interspecies differences limit comparison of lung pathology in CF mice to the human disease. The recent development of genetically modified pigs and ferrets heralds the application of more advanced animal models to CF research and drug development

Microstructure, precipitate and property evolution in cold-rolled Ti-V high strength low alloy steel

A cold-rolled Ti-V high strength low alloy (HSLA) steel was isothermally annealed at 650 °C and 700 °C for different times. A unique combination of techniques including visible light microscopy (VLM), transmission electron microscopy (TEM), matrix dissolution, small angle neutron scattering (SANS) and hardness measurement has been employed to investigate the evolution of microstructure, hardness and precipitate composition, size and volume fraction. Results show that recrystallization is completed after annealing 8 h at 650 °C and 30 min at 700 °C. Three types of precipitates were identified: large Ti(C,N), medium-size (Ti,V)(C,N) and small (Ti,V)C. The Ti/(Ti+V) atomic ratio in the (Ti,V)C precipitates decreases with increasing radius in the 1–15 nm range, which can be explained by the initial nucleation of a TiC-rich core. The average size of the (Ti,V)C precipitates increases, whereas the number density decreases during annealing. The volume fractions of the three types of precipitates were separately determined by the matrix dissolution method. The volume fractions of (Ti,V)C precipitates obtained by matrix dissolution are comparable even slightly more accurate than those obtained by SANS. The hardness first increases and then decreases when annealing at both temperatures, which can be correlated well with the observed microstructural and precipitate evolution.</p

Consequences of testing for mismatch repair deficiency of colorectal cancer in clinical practice

Molecular tumour pathology - and tumour geneticsMTG2 - Moleculaire genetica van gastrointestinale tumore