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Full-Text Articles in Physical Sciences and Mathematics

Variation Of Clonal, Mesquite-Associated Rhizobial And Bradyrhizobial Populations From Surface And Deep Soils By Symbiotic Gene Region Restriction Fragment Length Polymorphism And Plasmid Profile Analysis, P. M. Thomas, K.F. Golly, J. W. Zyskind, R. A. Virginia Jan 1994

Variation Of Clonal, Mesquite-Associated Rhizobial And Bradyrhizobial Populations From Surface And Deep Soils By Symbiotic Gene Region Restriction Fragment Length Polymorphism And Plasmid Profile Analysis, P. M. Thomas, K.F. Golly, J. W. Zyskind, R. A. Virginia

Dartmouth Scholarship

Genetic characteristics of 14 Rhizobium and 9 Bradyrhizobium mesquite (Prosopis glandulosa)-nodulating strains isolated from surface (0- to 0.5-rn) and deep (4- to 6-m) rooting zones were determined in order to examine the hypothesis that surface- and deep-soil symbiont populations were related but had become genetically distinct during adaptation to contrasting soil conditions. To examine genetic diversity, Southern blots of PstI-digested genomic DNA were sequentially hybridized with the nodDABC region of Rhizobium meliloti, the Klebsiella pneumoniae nifHDK region encoding nitrogenase structural genes, and the chromosome- localized ndvB region ofR. meliloti. Plasmid profile and host plant nodulation assays were also made. Isolates …


Ductile Saline Ice, G. A. Kuehn, E. M. Schulson Jan 1994

Ductile Saline Ice, G. A. Kuehn, E. M. Schulson

Dartmouth Scholarship

Experiments have shown that tensile ductility of about 5% or more can be imparted to columnar, saline ice by pre-compressing the material by about 3.5%. This effect is similar to that observed in granular, fresh-water ice and is attributed to the operation of both dislocation creep and diffusion creep within that part of the matrix which recrystallized during the pre-compressive deformation.