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Full-Text Articles in Environmental Sciences
The Influence Of Streambed Heterogeneity On Hyporheic Exchange In Gravelly Rivers, Yaoquan Zhou
The Influence Of Streambed Heterogeneity On Hyporheic Exchange In Gravelly Rivers, Yaoquan Zhou
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Hyporheic exchange can be influenced by channel meanders, by streambed topography, and by the heterogeneity within subsurface sediments. Fluvial systems with streambed sediments composed of sandy gravel can be heterogeneous and contain open-framework gravel stratasets that comprise roughly one-third of the sedimentary deposit by volume. The open-framework gravel stratasets have an average lateral length scale on the order of 10 m, average thickness on the order of a decimeter, and an average dip on the order of 10 degrees downstream. The hydraulic conductivity of open-framework gravel stratasets is on the order of 10-1 m/s, and for the larger volume of …
Among-Locus Heterogeneity In Genetic Diversity And Divergence In Two Pairs Of Duck Species (Genus: Anas), Kirandeep K. Dhami
Among-Locus Heterogeneity In Genetic Diversity And Divergence In Two Pairs Of Duck Species (Genus: Anas), Kirandeep K. Dhami
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Genetic diversity and divergence at a locus are the result of interactions among the fundamental evolutionary forces of mutation, genetic drift, gene flow and natural selection. Variation in the strength of these forces can cause high heterogeneity in diversity and divergence across the genome. The overall objective of this thesis was to examine the role of population history vs. selection in generating heterogeneity in genetic diversity and differentiation. In Chapter 1, I examine the role of dispersal behavior in causing genetic differentiation and population structure within and between two morphologically distinct Australian duck species that differ in ecology and life …