Copies of full items can be used for personal research or study, educational, or not-forprofit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. AbstractThe dielectric and piezoelectric properties of ferroelectric polycrystalline materials have long been known to be strong functions of grain size and extrinsic effects such as domain wall motion. In BaTiO 3 , for example, it has been observed for several decades that the piezoelectric and dielectric properties are maximized at intermediate grain sizes (~1 μm) and different theoretical models have been introduced to describe the physical origin of this effect. Here, using in situ, high-energy X-ray diffraction during application of electric fields, we show that 90° domain wall motion during both strong (above coercive) and weak (below coercive) electric fields is greatest at these intermediate grain sizes, correlating with the enhanced permittivity and

The ferroelectric domain structure of pure Na 1/2 Bi 1/2 TiO 3 (NBT) and 1 at.% Mn-doped NBT (Mn-NBT) crystals was investigated by piezoresponse force microscopy. The correlation length of the polar regions was found to increase upon Mn substitution. High resolution transmission electron microscopy revealed that the coherency of the lattice across the domain boundaries between polar regions was also enhanced. Selected area electron diffraction showed that Mn favored coexisting 1/2 (ooo) and 1/2 (ooe) oxygen octahedral tiltings, over only 1/2 (ooo) for pure NBT. V C 2012 American Institute of Physics. [http://dx.

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Spoken language comprehension requires listeners map continuous features of the speech signal to discrete category labels. Categories are however malleable to surrounding context; listeners’ percept can dynamically shift depending on the sequencing of adjacent stimuli resulting in a warping of the heard phonetic category (i.e., hysteresis). Here, we investigated whether such perceptual nonlinearities—which amplify categorical hearing—might further aid speech processing in noise-degraded listening scenarios. We measured continuous dynamics in perception and category judgments of an acoustic-phonetic vowel gradient via mouse tracking. Tokens were presented in serial vs. random orders to induce more/less perceptual warping while listeners categorized continua in clean and noise conditions. Listeners’ responses were faster and their mouse trajectories closer to the ultimate behavioral selection (marked visually on the screen) in serial vs. random order, suggesting increased perceptual attraction to category exemplars. Interestingly, order effects emerged earlier and persisted later in the trial time course when categorizing speech in noise. These data describe a new functional benefit of perceptual nonlinearities to speech perception yet undocumented: warping strengthens the behavioral attraction to relevant speech categories while simultaneously assisting perception in degraded acoustic environments.