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Abstract We evaluate the efficacy of the stable isotope composition of precipitation and plant waxes as proxies for paleoaltimetry and paleohydrology in the northern tropical Andes. We report monthly hydrogen (δ2Hp) and oxygen (δ18Op) isotope values of precipitation for an annual cycle, and hydrogen isotope values of plant waxes (δ2Hwax) obtained from modern soils along the eastern and western flanks of the Eastern Cordillera of Colombia. δ2Hp, δ18Op, as well as the unweighted mean δ2Hwaxvalues ofn‐C29,n‐C31, andn‐C33n‐alkanes in the eastern flank show a dependence on elevation (R2 = 0.90, 0.82, and 0.65, respectively). In stark contrast, the stable isotope compositions of neither precipitation nor plant waxes from the western flank correlate with elevation (R2 < 0.23), on top of a negligible (p‐value >0.05) correlation between δ2Hwaxand δ2Hp. In general, δ2Hwaxvalues along the eastern flank of the Eastern Cordillera seem to follow the trend of a simple Rayleigh distillation process that is consistent with studies elsewhere on the eastern side of the Andes in South America. Neither δ2Hpnor δ18Op, and therefore δ2Hwax, offer reliable estimates of past elevations in the western flank, due perhaps to water vapor source mixing, evaporation overprint, contrasting plant communities, and/or differences in evapotranspiration. Thus, δ2Hwaxis only reliable for paleohydrology and paleoaltimetry reconstructions on the eastern flank of the Andes, whereas interpretations based on δ2Hpand/or δ18Opwest of the highest point of the Eastern Cordillera need to consider mixing of moisture sources in addition to precipitation amount.
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Duplex-forming oligocarbamates with tunable nonbonding sites
Sequence-defined oligocarbamates with thymine and diaminotriazine pendant groups assemble into duplexes. The binding strength (Ka), enthalpy (ΔH), and entropy (ΔS) of hybridization depend on the valency and sequence of the interacting ligands.
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- Award ID(s):
- 2105834
- PAR ID:
- 10557993
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Chemical Science
- Volume:
- 15
- Issue:
- 24
- ISSN:
- 2041-6520
- Page Range / eLocation ID:
- 9138 to 9146
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D4SC00242C
