16 research outputs found

    Two Ideas of the Redox Reaction: Misconceptions and their Challenge in Chemistry Education

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    In interpretations of chemical phenomena students like to mix the macro level of substances with the sub-micro level of atoms, ions and molecules: “water boils at 100 oC and has an angle” – instead of separating properties of substances (water has a special density, freezing and boiling point) and properties of particles (the H2O molecule has an angle, H and O atoms are linked by electron-pair bond). For redox reactions students are doing this too: “one Cu2+ ion takes two electrons and is reduced to copper” – instead of “to one Cu atom”! Another difficulty seems to be the historical redox definition with the “oxygen transfer”: this idea is so attractive that students argue mostly with oxygen participation instead of the transfer of electrons. This article reflects those misconceptions and proposes ways of instruction to prevent from “schoolmade misconceptions”

    Microbiomes of ant castes implicate new microbial roles in the fungus-growing ant Trachymyrmex septentrionalis

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    Fungus-growing ants employ several defenses against diseases, including disease-suppressing microbial biofilms on their integument and in fungal gardens. Here, we compare the phenology of microbiomes in natural nests of the temperate fungus-growing ant Trachymyrmex septentrionalis using culture-dependent isolations and culture-independent 16S-amplicon 454-sequencing. 454-sequencing revealed diverse actinobacteria associated with ants, including most prominently Solirubrobacter (12.2–30.9% of sequence reads), Pseudonocardia (3.5–42.0%), and Microlunatus (0.4–10.8%). Bacterial abundances remained relatively constant in monthly surveys throughout the annual active period (late winter to late summer), except Pseudonocardia abundance declined in females during the reproductive phase. Pseudonocardia species found on ants are phylogenetically different from those in gardens and soil, indicating ecological separation of these Pseudonocardia types. Because the pathogen Escovopsis is not known to infect gardens of T. septentrionalis, the ant-associated microbes do not seem to function in Escovopsis suppression, but could protect against ant diseases, help in nest sanitation, or serve unknown functions
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