Lorentz breaking Effective Field Theory and observational tests

Analogue models of gravity have provided an experimentally realizable test field for our ideas on quantum field theory in curved spacetimes but they have also inspired the investigation of possible departures from exact Lorentz invariance at microscopic scales. In this role they have joined, and sometime anticipated, several quantum gravity models characterized by Lorentz breaking phenomenology. A crucial difference between these speculations and other ones associated to quantum gravity scenarios, is the possibility to carry out observational and experimental tests which have nowadays led to a broad range of constraints on departures from Lorentz invariance. We shall review here the effective field theory approach to Lorentz breaking in the matter sector, present the constraints provided by the available observations and finally discuss the implications of the persisting uncertainty on the composition of the ultra high energy cosmic rays for the constraints on the higher order, analogue gravity inspired, Lorentz violations.Comment: 47 pages, 4 figures. Lecture Notes for the IX SIGRAV School on "Analogue Gravity", Como (Italy), May 2011. V.3. Typo corrected, references adde

Phonetic Activity in Reading: an Experiment With Kanji

Reading seems to require phonetic short-term storage even if the writing system is logographic. A short-term memory probe paradigm was used to test the ability of Japanese subjects to recall kanji characters. When pairs of characters in a silently read list were homophonous, recall was significantly poorer than when the silently read list included no such pairs, presumably because of confusion in phonetic short-term storage. Since the kanji have no overt phonetic structure, it would seem that this kind of storage is involved in the reading of kanji not because of the particular structure of the writing system but because of the essentially linguistic nature of the task. Evidently the linguistic process cannot readily disperse with phonetic short-term storage. It is suggested, however, that the design of a writing system does not depend directly on linguistic process but rather on the partial and uneven awareness that users of the system have of certain aspects of this process. </jats:p

Spelling–stress regularity effects are intact in developmental dyslexia

The current experiment investigated conflicting predictions regarding the effects of spelling–stress regularity on the lexical decision performance of skilled adult readers and adults with developmental dyslexia. In both reading groups, lexical decision responses were significantly faster and significantly more accurate when the orthographic structure of a word ending was a reliable as opposed to an unreliable predictor of lexical stress assignment. Furthermore, the magnitude of this spelling–stress regularity effect was found to be equivalent across reading groups. These findings are consistent with intact phoneme-level regularity effects also observed in dyslexia. The paper discusses how findings of intact spelling–sound regularity effects at both prosodic and phonemic levels, as well as other similar results, can be reconciled with the obvious difficulties that people with dyslexia experience in other domains of phonological processing