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Abstract: Twenty five rhizobial isolates were obtained from root nodules of Medicago sativa inoculated with soil samples collected from the Sapporo region and Ishigaki Island in Japan. To study their diversity and characterize them in relation to the climatic conditions of their soils of origin, a polyphasic approach analyzing stress tolerance, symbiotic and genetic properties was used. Stress tolerance assays revealed marked variations in salinity, pH and temperature tolerance. Isolates originating from a sub-tropical climate in alkaline soil (Ishigaki Island) tolerated high temperature, salinity and pH levels. Moreover, isolates recovered from a temperate climate in acidic soil (Sapporo) were sensitive to high temperature and salinity, and tolerated acidic pH. Phylogenetic analysis of conserved 16S rRNA and recA genes, and symbiotic nodA and nifDK revealed 25 isolates to be closely related to Ensifer meliloti. Furthermore, the branch patterns of phylogenetic trees constructed from different genes revealed the existence of at least two E. meliloti types in the soils studied. These results may be relevant to programs directed towards improving crop productivity through biofertilization with locally adapted and genetically defined strains. [Copyright &y& Elsevier]

• To assess the damage of concrete structure subjected to freeze-thawed effects. • A method to monitor AE energy activity of core samples under uniaxial compressive loading was investigated. • The degree of damage was visualized using X-ray CT images. • Quantification of concrete damage was analyzed relation between AE energy parameter and accumulation of cracks. As a detailed inspection of a concrete structure in service, core samples are usually drilled out and then mechanical properties are measured. In this study, damage estimation of freeze-thawed concrete from concrete-core samples is developed, applying acoustic emission (AE) method. By the authors, the quantitative damage evaluation of concrete has been proposed in RILEM TC −212ACD, by applying AE and damage mechanics in the compression test. In this study, characteristics evaluation of cracking damage effects in concrete mechanical properties by detected AE energy in core test. Prior to the compression test, distribution of micro-cracks in a concrete-core sample is inspected by helical X-ray computer tomography (CT). Then, freeze-thawed damaged samples are tested by the compression test with AE monitoring. Concrete-core samples were taken out of a channel structures in Hokkaido, Japan which is extremely developed cracking damage. Thus, it is demonstrated that the concentration of material damage could be evaluated by comparing geometrical characteristics of cracks with the "energy rate" of AE generation, which is analyzed by AE parameter analysis. A relation between AE energy rate, physical properties and geometrical properties of void is correlated, and thus the damage of concrete is qualitatively estimated by AE parameters. [ABSTRACT FROM AUTHOR]