Magnetic testing probe

A cylindrical eddy current tube testing probe is disclosed. Current flow in dual electromagnetic coils separated by an eddy current sensing coil is so directed that magnetic fields of the electromagnet coils have components extending in opposite directions axially of the tested tube and components extending radially of the tube which add in the region of the eddy current sensing coil

Heritability of the structures and¹³C fractionation in tomato leaf wax alkanes: a genetic model system to inform paleoenvironmental reconstructions

AbstractLeaf waxn-alkanes are broadly used to reconstruct paleoenvironmental information. However, the utility of then-alkane paleoclimate proxy is modulated by the extent to which genetic as well as environmental factors influence the structural and isotopic variability of leaf waxes. In paleoclimate applications, there is an implicit assumption that most variation of leaf wax traits through a time series can be attributed to environmental change and that biological sources of variability within plant communities are small. For example, changes in hydrology affect the δ2H of waxes though rainwater and the δ13C of leaf waxes by changing plant communities (i.e., C3versus C4input). Here we test the assumption of little genetic control over 5 C variation of leaf wax by presenting the results of an experimental greenhouse growth study in which we estimate the role of genetic variability on structural and isotopic leaf wax traits in a set of 76 introgression lines (ILs) between two interfertileSolanum(tomato) species:S. lycopersicumcv M82 (hereafter cv M82) andS. pennellii.We found that the leaves ofS. pennellii,a wild desert tomato relative, produces significantly moreiso-alkanes than cv M82, a domesticated tomato cultivar adapted to water-replete conditions; we introduce a methylation index to summarize the ratio of branched (iso- andanteiso-) to total alkanes. BetweenS. pennelliiand cv M82, theiso-alkanes were found to be enriched in13C by 1.2–1.4%o overn-alkanes. By modeling our results from the ILs, we report the broad-sense heritability values (H2) of leaf wax traits to describe the degree to which genetic variation contributes to variation of these traits. Individual carbon isotope values of alkanes are of low heritability (H2= 0.13–0.19), suggesting that δ13C of leaf waxes from this study are strongly influenced by environmental variance, which supports the interpretation that variation in the 5 C of wax compounds recorded in sediments reflects paleohydrological changes. Average chain length (ACL) values ofn-alkanes are of intermediate heritability (H2= 0.30), suggesting that ACL values are strongly influenced by genetic cues.</jats:p