109,249 research outputs found

    Toward an ecological aesthetics: music as emergence

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    In this article we intend to suggest some ecological based principles to support the possibility of develop an ecological aesthetics. We consider that an ecological aesthetics is founded in concepts as “direct perception”, “acquisition of affordances and invariants”, “embodied embedded perception” and so on. Here we will purpose that can be possible explain especially soundscape music perception in terms of direct perception, working with perception of first hand (in a Gibsonian sense). We will present notions as embedded sound, detection of sonic affordances and invariants, and at the end we purpose an experience with perception/action paradigm to make soundscape music as emergence of a self-organized system

    The lattice Landau gauge gluon propagator: lattice spacing and volume dependence

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    The interplay between the finite volume and finite lattice spacing is investigated using lattice QCD simulations to compute the Landau gauge gluon propagator. Comparing several ensembles with different lattice spacings and physical volumes, we conclude that the dominant effects, in the infrared region, are associated with the use of a finite lattice spacing. The simulations show that decreasing the lattice spacing, while keeping the same physical volume, leads to an enhancement of the infrared gluon propagator. In this sense, the data from ÎČ=5.7\beta=5.7 simulations, which uses an a≈0.18a \approx 0.18 fm, provides a lower bound for the infinite volume propagator.Comment: Final version to appear in Phys Rev

    2013 REU Poster: Purification and Characterization of a Ferredoxin from Mycobacterium tuberculosis

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    Poster presentation at REU Summer's End Research Symposium, 2013, by REU participant Jonas A, de Oliveira, MassBay Community College - Sean Elliott group, Evan Judd lab mentorM. tuberculosis possesses a sulfite reductase (MtsirA) that is over-expressed when the bacteria is in its dormant stage of infection. MtSirA catalyzes the six-electron reduction of sulfite to sulfide. Previous kinetic studies of MtsirA have used methyl viologen (MV), a chemical reductant, as an electron donor. The goal of this work is to purify and characterize a ferredoxin from M. tuberculosis (MtFd) and determine if MtFd can act as an electron donor to mtSirA, with the ultimate goal of using it as a more physiologically relevant electron donor in kinetic studies of mtSirA. We have found that that MtFd purifies without a cluster and must be chemically reconstituted. MtFd likely contains a [4Fe-4S] cluster, and may be able to donate electrons to mtSirA.NSF-RE