192,242 research outputs found
The effect of high- and low-frequency previews and sentential fit on word skipping during reading
No full textIn a previous gaze-contingent boundary experiment, Angele and Rayner (2013) found that readers are likely to skip a word that appears to be the definite article the even when syntactic constraints do not allow for articles to occur in that position. In the present study, we investigated whether the word frequency of the preview of a 3-letter target word influences a reader’s decision to fixate or skip that word. We found that the word frequency rather than the felicitousness (syntactic fit) of the preview affected how often the upcoming word was skipped. These results indicate that visual information about the upcoming word trumps information from the sentence context when it comes to making a skipping decision. Skipping parafoveal instances of the therefore may simply be an extreme case of skipping high-frequency words
Verdazyl radicals as mediators in living radical polymerisation and dopamine end-functionalised polymers for application as friction modifiers
No full textVerdazyl Radicals as Mediators in Living Radical Polymerisation:
The aim of this work was to investigate verdazyl radicals as an alternative to
nitroxides as mediators in stable free radical polymerisation. Verdazyl radicals and
their unimolecular initiators were synthesised and utilised in the polymerisation of
styrene and n-butyl acrylate. Varying degrees of success was observed in the
polymerisations depending on the structure of the verdazyl radical. The
polymerisation of methyl methacrylate and the copolymerisation of styrene and
methyl methacrylate were also investigated. Correlations between observed
molecular weight and theoretical molecular weight were poor but may be improved
by optimisation of the reaction conditions. Electron paramagnetic resonance was
used to elucidate the radical structure as well as to confirm the living nature of the
polymerisation technique. Electron paramagnetic resonance was also utilised to
provide an insight into radical stability and reactivity in the various reactions
undertaken.
Dopamine End-Functionalised Polymers for Application as Friction
Modifiers:
The aim of this work was to synthesise oil soluble dopamine end-functionalised
polymers for mechanical testing to determine if the polymers can reduce friction by
film formation at a surface. A dopamine based initiator was synthesised and used in Cu(I) and Cu(0) mediated polymerisations with little success and the dopamine
catecholic end-group could not be identified as the polymer end-group. To enable a
successful living polymerisation, the catechol groups on dopamine required
protection. Complete deprotection of the catechol group can be achieved post
polymerisation. The polymerisation of lauryl methacrylate was achieved using a
polymerisation method designed for the long chain, non-polar molecule which
utilised Cu(I)Cl. The polymerisations were scaled up to obtain a baseline, protected
dopamine and deprotected dopamine polymers for mechanical testing. A reduction
in friction and wear observed for the deprotected dopamine polymer, however,
corrosion was also observed and may have affected the results
Binocular coordination: Reading stereoscopic sentences in depth
No full textThe present study employs a stereoscopic manipulation to present sentences in three dimensions to subjects as they read for comprehension. Subjects read sentences with (a) no depth cues, (b) a monocular depth cue that implied the sentence loomed out of the screen (i.e., increasing retinal size), (c) congruent monocular and binocular (retinal disparity) depth cues (i.e., both implied the sentence loomed out of the screen) and (d) incongruent monocular and binocular depth cues (i.e., the monocular cue implied the sentence loomed out of the screen and the binocular cue implied it receded behind the screen). Reading efficiency was mostly unaffected, suggesting that reading in three dimensions is similar to reading in two dimensions. Importantly, fixation disparity was driven by retinal disparity; fixations were significantly more crossed as readers progressed through the sentence in the congruent condition and significantly more uncrossed in the incongruent condition. We conclude that disparity depth cues are used on-line to drive binocular coordination during reading.<br/
Eye movements and the use of parafoveal word length information in reading
No full textEye movements were monitored in 4 experiments that explored the role of parafoveal word length in reading. The experiments employed a type of compound word where the deletion of a letter results in 2 short words (e.g., backhand, back and). The boundary technique (K. Rayner, 1975) was employed to manipulate word length information in the parafovea. Accuracy of the parafoveal word length preview significantly affected landing positions and fixation durations. This disruption was larger for 2-word targets, but the results demonstrated that this interaction was not due to the morphological status of the target words. Manipulation of sentence context also demonstrated that parafoveal word length information can be used in combination with sentence context to narrow down lexical candidates. The 4 experiments converge in demonstrating that an important role of parafoveal word length information is to direct the eyes to the center of the parafoveal word
Recommended from our members
Using E-Z Reader to examine the concurrent development of eye-movement control and reading skill
No full textCompared to skilled adult readers, children typically make more fixations that are longer in duration, shorter saccades, and more regressions, thus reading more slowly (Blythe & Joseph, 2011). Recent attempts to understand the reasons for these differences have discovered some similarities (e.g., children and adults target their saccades similarly; Joseph, Liversedge, Blythe, White, & Rayner, 2009) and some differences (e.g., children’s fixation durations are more affected by lexical variables; Blythe, Liversedge, Joseph, White, & Rayner, 2009) that have yet to be explained. In this article, the E-Z Reader model of eye-movement control in reading (Reichle, 2011; Reichle, Pollatsek, Fisher, & Rayner, 1998) is used to simulate various eye-movement phenomena in adults versus children in order to evaluate hypotheses about the concurrent development of reading skill and eye-movement behavior. These simulations suggest that the primary difference between children and adults is their rate of lexical processing, and that different rates of (post-lexical) language processing may also contribute to some phenomena (e.g., children’s slower detection of semantic anomalies; Joseph et al., 2008). The theoretical implications of this hypothesis are discussed, including possible alternative accounts of these developmental changes, how reading skill and eye movements change across the entire lifespan (e.g., college-aged vs. older readers), and individual differences in reading ability
Author reply to Hettiarachchi et al. (re Helicobacter pylori resistance in Australia…)
No full textLetter to the EditorJonathon P. Schubert, Paul R. Ingram, Morgyn S. Warner, Christopher K. Rayner, Ian C. Roberts-Thomson, Samuel P. Costello and Robert V. Bryan
Rayner Heppenstall : Tales from the «Newgate Calendar », 1981
No full textDuval Gilles. Rayner Heppenstall : Tales from the «Newgate Calendar », 1981. In: Dix-huitième Siècle, n°16, 1984. D'Alembert. p. 467
Investigation of the Heck reaction and the associated catalytic systems using XAFS and Phosphorus NMR techniques
No full textThe main body of work was conducted on the Heck reaction between 2-methylprop-22-en-1-01 and PhX (X = C1, Br and I) to form 1-phenyl-2-methyl-propanal catalysed by the systems already examined in this thesis (the systems were also extended to include other phosphine ligands (tri(1-napthyl)phosphine and tris(o-methoxyphenyl)phosphine) and 3b as catalyst). The results showed a variety of catalytic properties, from tricyclohexylphosphine which prevents any catalysis, to tri(t-butyl)phosphine which promotes catalysis in all reactions. Reactions catalysed by palladium acetate and tri-o-tolylphosphine, showed that the main phosphorus species present in solution were different, compared with using 1 as catalyst. As the reactions which were catalysed proceeded, the extent of halogenation to the palladium increased. Halogenated species present for reactions catalysed by palladacycles were of the form: (P-C)PdX(solv), ([P-C)PdX2-] and [(P-C)P(m-X)] (where (P-C) is the palladated ring) and Pd(PR3)2(Ph)X, [Pd(Ph)(PR3)(m-X)]2 and [PdX(PR3)(m-X)]2 for reactions catalysed by palladium acetate and phosphine ligand. It was noted for uncatalysed reactions that there was negligible or no coordination of halogen to the metal, which suggests that this is an important early step in the catalytic cycle. Enforced, since heating the catalytic species (1) with PhI led to a stable mixture of species, whilst heating with alcohol led to decomposition of the metal precatalytic complex and liberation of free phosphine. Also, Pd(PtBu3)2 was isolated from the PhBr reaction catalysed by Pd(OAc)2 / PtBu3 and characterised by X-ray crystallography.</p
- …
