2,608 research outputs found
Sonophilia / Sonophobia: Sonic Others in the Poetry of Edward Sapir
One of the key findings in early visual culture studies is a profound ambivalence toward images, which is intricately tied up with hegemonic conceptions of cultural, racial, and sexual Others. Starting from W. J. T. Mitchell’s diagnosis of iconophilia and iconophobia for visual culture, Iargue that recent sound studies yield parallel conclusions with regard to sonic culture, as scholars such as Jonathan Sterne point to a long tradition of writing on sound that is also characterized by attraction to and repulsion of media and sign systems other than written language. On the basis of a theoretical conception of what I term sonophilia and sonophobia, then, this essay asserts that it is precisely the ambivalence toward sound that is at the center of the poetry of anthropologist and linguist Edward Sapir. In their treatment of auditory sense perceptions as the Other of written language, Sapir’s poems “Music” and “Zuni” attest to the fact that not only images but notions of sound, too, are shaped by ideological associations embedded in semiotic and sensory oppositions
Increasing the coherence time of Bose-Einstein-condensate interferometers with optical control of dynamics
Atom interferometers using Bose-Einstein condensate that is confined in a
waveguide and manipulated by optical pulses have been limited by their short
coherence times. We present a theoretical model that offers a physically simple
explanation for the loss of contrast and propose the method for increasing the
fringe contrast by recombining the atoms at a different time. A simple,
quantitatively accurate, analytical expression for the optimized recombination
time is presented and used to place limits on the physical parameters for which
the contrast may be recovered.Comment: 34 Pages, 8 Figure
Generalized cross validation for â„“ p-â„“ q minimization
Discrete ill-posed inverse problems arise in various areas of science and engineering. The presence of noise in the data often makes it difficult to compute an accurate approximate solution. To reduce the sensitivity of the computed solution to the noise, one replaces the original problem by a nearby well-posed minimization problem, whose solution is less sensitive to the noise in the data than the solution of the original problem. This replacement is known as regularization. We consider the situation when the minimization problem consists of a fidelity term, that is defined in terms of a p-norm, and a regularization term, that is defined in terms of a q-norm. We allow 0 < p,q ≤ 2. The relative importance of the fidelity and regularization terms is determined by a regularization parameter. This paper develops an automatic strategy for determining the regularization parameter for these minimization problems. The proposed approach is based on a new application of generalized cross validation. Computed examples illustrate the performance of the method proposed
Limited memory restarted l(p)-l(q) minimization methods using generalized Krylov subspaces
Regularization of certain linear discrete ill-posed problems, as well as of certain regression problems, can be formulated as large-scale, possibly nonconvex, minimization problems, whose objective function is the sum of the p(th) power of the l(p)-norm of a fidelity term and the qth power of the lq-norm of a regularization term, with 0 < p,q = 2. We describe new restarted iterative solution methods that require less computer storage and execution time than the methods described by Huang et al. (BIT Numer. Math. 57,351-378, 14). The reduction in computer storage and execution time is achieved by periodic restarts of the method. Computed examples illustrate that restarting does not reduce the quality of the computed solutions
One-spin quantum logic gates from exchange interactions and a global magnetic field
It has been widely assumed that one-qubit gates in spin-based quantum
computers suffer from severe technical difficulties. We show that one-qubit
gates can in fact be generated using only modest and presently feasible
technological requirements. Our solution uses only global magnetic fields and
controllable Heisenberg exchange interactions, thus circumventing the need for
single-spin addressing.Comment: 4 pages, incl. 1 figure. This significantly modified version accepted
for publication in Phys. Rev. Let
Specificity of plant microRNA target MIMICs: cross-targeting of miR159 and miR319
Plant microRNA (miRNA) target MIMICs (MIMs) are non-coding RNA transcripts that can inhibit endogenous miRNAs, as they contain a miRNA binding site that forms a three nucleotide (nt) mismatch loop opposite the miRNA cleavage site upon miRNA binding. This loop renders the MIMs non-cleavable, presumably leading to sequestration of the miRNA and thus enabling the endogenous targets to be deregulated. Arabidopsis miR319 and miR159 are two closely related but distinct miRNA families, as they are functionally specific for two different sets of targets, TCP and MYB genes, respectively. Being offset by one nt, MIM319 and MIM159 should have specificity to their respective miRNA families. However, MIM319 and MIM159 plants appear indistinguishable, having highly similar developmental defects reminiscent of a loss-of-function mir159 mutant. In both MIM319 and MIM159 plants, miR159 and miR319 levels are reduced, and correspondingly, both MYB and TCP mRNA levels are elevated, implying that these MIMs are inhibiting both miR159 and miR319. These data demonstrate that MIMs are able to inhibit closely related miRNAs, including those with cleavage sites not opposite the three nt loop. This highlights that MIMs can have unintended off-target effects and that their use should include corresponding molecular analysis to investigate their impact on closely related miRNAs.This research was supported by an Australian Research Council grant DP130103697 and an International ANU PhD scholarship to M.R
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