Hunter G. Close

Learn More
Throughout the Proterozoic δ(13)C values for preserved n-alkyl lipids are more positive than for syngenetic kerogen. This pattern is the inverse of biosynthetic expectations. It has been suggested that this isotopic inversion results from selective preservation of lipids from (13)C-enriched heterotrophic populations, while the bulk of kerogen derives from(More)
The nature of energy is not typically an explicit topic of physics instruction. Nonetheless, verbal and graphical representations of energy articulate models in which energy is conceptualized as a quasimaterial substance, a stimulus, or a vertical location. We argue that a substance ontology for energy is particularly productive in developing understanding(More)
The nature of energy is not typically an explicit topic of physics instruction. Nonetheless, verbal and graphical representations of energy articulate models in which energy is conceptualized as a quasi-material substance, a stimulus, or a vertical location. We argue that a substance ontology for energy is particularly productive in developing understanding(More)
  • 1