191 research outputs found
Multi-level processing of phonetic variants in speech production and visual word processing: evidence from Mandarin lexical tones
Theoretical and Experimental Linguistic
Pupil responses associated with coloured afterimages are mediated by the magno-cellular pathway
Sustained fixation of a bright coloured stimulus will, on extinction of the stimulus and continued steady fixation, induce an afterimage whose colour is complementary to that of the initial stimulus; an effect thought to be caused by fatigue of cones and/or of cone-opponent processes to different colours. However, to date, very little is known about the specific pathway that causes the coloured afterimage. Using isoluminant coloured stimuli recent studies have shown that pupil constriction is induced by onset and offset of the stimulus, the latter being attributed specifically to the subsequent emergence of the coloured afterimage. The aim of the study was to investigate how the offset pupillary constriction is generated in terms of input signals from discrete functional elements of the magno- and/or parvo-cellular pathways, which are known principally to convey, respectively, luminance and colour signals. Changes in pupil size were monitored continuously by digital analysis of an infra-red image of the pupil while observers viewed isoluminant green pulsed, ramped or luminance masked stimuli presented on a computer monitor. It was found that the amplitude of the offset pupillary constriction decreases when a pulsed stimulus is replaced by a temporally ramped stimulus and is eliminated by a luminance mask. These findings indicate for the first time that pupillary constriction associated with a coloured afterimage is mediated by the magno-cellular pathway. © 2003 Elsevier Science Ltd. All rights reserved
Evidence for covert attention switching from eye-movements. Reply to commentaries on Liechty et al., 2003
We argue that our research objectives in Liechty, Pieters, and Wedel (2003) are to provide generalizable insights into covert visual attention to complex, multimodal stimuli in their natural context, through inverse inference from eye-movement data. We discuss the most important issues raised by Feng (2003) and Reichle and Nelson (2003), in particular the task definition, inclusion of ad features, object-based versus space-based attention and the evidence for the where and what streams.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45760/1/11336_2005_Article_BF02295611.pd
Chelation in Metal Intoxication
Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents) or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications
Voting on sustainable transport: communication and governance challenges in Greater Manchester's ‘congestion charge’ referendum
In December 2008, the Greater Manchester electorate voted to reject a £3 billion package of transport measures that would have included investment in the conurbation's bus, tram and rail networks and walking and cycling infrastructure, together with, and partially funded by, the introduction of a congestion charge. The proposals followed a successful bid to the UK Government Transport Innovation Fund (TIF). High levels of car use present challenges to cities, and the TIF bid can be seen as an attempt to address these by promoting and facilitating a modal shift. The paper reflects on the debates surrounding the proposals, which led to a referendum. In particular, it explores the challenges of communicating complex, controversial plans in a fragmented and contested political arena
Polarised quark distributions in the nucleon from semi-inclusive spin asymmetries
We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1~GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10~GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1 GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1 GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1 GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1 GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0031 GeV 2 . Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q 2 =10 GeV 2 . The polarised u valence quark distribution, Δu v ( x ), is positive and the polarisation increases with x . The polarised d valence quark distribution, Δd v ( x ), is negative and the non-strange sea distribution, Δ q ̄ (x) , is consistent with zero over the measured range of x . We find for the first moments ∫ 0 1 Δu v (x) d x=0.77±0.10±0.08 , ∫ 0 1 Δd v (x) d x=−0.52±0.14±0.09 and ∫ 0 1 Δ q ̄ (x) d x=0.01±0.04±0.03 , where we assumed Δ u ̄ (x)=Δ d ̄ (x) . We also determine for the first time the second moments of the valence distributions ∫ 0 1 xΔq v (x) d x
Ocorrência e caracterização da tuberculose em caprinos leiteiros criados no estado de Pernambuco
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