Browsing by Subject "nature"

Now showing 1 - 3 of 3
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    A Dilemma for Mathematical Constructivism
    (Springer, 2021) Kahn, Samuel; Philosophy, School of Liberal Arts
    In this paper I argue that constructivism in mathematics faces a dilemma. In particular, I maintain that constructivism is unable to explain (1) the application of mathematics to nature and (2) the intersubjectivity of mathematics unless (3) it is conjoined with two theses that reduce it to a form of mathematical Platonism. The paper is divided into five sections. In the first section of the paper, I explain the difference between mathematical constructivism and mathematical Platonism and I outline my argument. In the second, I argue that the best explanation of how mathematics applies to nature for a constructivist is a thesis I call Copernicanism. In the third, I argue that the best explanation of how mathematics can be intersubjective for a constructivist is a thesis I call Ideality. In the fourth, I argue that once constructivism is conjoined with these two theses, it collapses into a form of mathematical Platonism. In the fifth, I confront some objections.
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    Diversity and abundance of phosphonate biosynthetic genes in nature
    (2013-12) Yu, Xiaomin; Doroghazi, James R.; Janga, Sarath Chandra; Zhang, Jun Kai; Circello, Benjamin; Griffin, Benjamin M.; Labeda, David P.; Metcalf, William W.
    Phosphonates, molecules containing direct carbon–phosphorus bonds, compose a structurally diverse class of natural products with interesting and useful biological properties. Although their synthesis in protozoa was discovered more than 50 y ago, the extent and diversity of phosphonate production in nature remains poorly characterized. The rearrangement of phosphoenolpyruvate (PEP) to phosphonopyruvate, catalyzed by the enzyme PEP mutase (PepM), is shared by the vast majority of known phosphonate biosynthetic pathways. Thus, the pepM gene can be used as a molecular marker to examine the occurrence and abundance of phosphonate-producing organisms. Based on the presence of this gene, phosphonate biosynthesis is common in microbes, with ∼5% of sequenced bacterial genomes and 7% of genome equivalents in metagenomic datasets carrying pepM homologs. Similarly, we detected the pepM gene in ∼5% of random actinomycete isolates. The pepM-containing gene neighborhoods from 25 of these isolates were cloned, sequenced, and compared with those found in sequenced genomes. PEP mutase sequence conservation is strongly correlated with conservation of other nearby genes, suggesting that the diversity of phosphonate biosynthetic pathways can be predicted by examining PEP mutase diversity. We used this approach to estimate the range of phosphonate biosynthetic pathways in nature, revealing dozens of discrete groups in pepM amplicons from local soils, whereas hundreds were observed in metagenomic datasets. Collectively, our analyses show that phosphonate biosynthesis is both diverse and relatively common in nature, suggesting that the role of phosphonate molecules in the biosphere may be more important than is often recognized.
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    Nature in 19th Century German Literature
    (Office of the Vice Chancellor for Research, 2014-04-11) Jones, Chad L
    Author will be presenting the research from capstone course on nature’s thematic role in 19th Century German literature. Author will present and analyze three texts; Elective Affinities by Johann Wolfgang von Goethe, Lenz by Georg Büchner, and Rock Crystal by Adalbert Stifter. The ‘landscape’ of Elective Affinities by Johann Wolfgang von Goethe presents the subdued aspect of nature and society’s ability to control the environment following the scientific revolution. In Georg Büchner’s Lenz, nature’s unpredictability and chaotic state is observed overwhelming Lenz’s schizophrenic mind. Finally, the limits that nature sets for modernity and the borders it constructs for society in Rock Crystal by Adalbert Stifter. Mentor: Thorsten Carstensen, Department of World Languages and Cultures, IU School of Liberal Arts