15 resultados para Eyes

em CentAUR: Central Archive University of Reading - UK


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With both climate change and air quality on political and social agendas from local to global scale, the links between these hitherto separate fields are becoming more apparent. Black carbon, largely from combustion processes, scatters and absorbs incoming solar radiation, contributes to poor air quality and induces respiratory and cardiovascular problems. Uncertainties in the amount, location, size and shape of atmospheric black carbon cause large uncertainty in both climate change estimates and toxicology studies alike. Increased research has led to new effects and areas of uncertainty being uncovered. Here we draw together recent results and explore the increasing opportunities for synergistic research that will lead to improved confidence in the impact of black carbon on climate change, air quality and human health. Topics of mutual interest include better information on spatial distribution, size, mixing state and measuring and monitoring. (c) 2006 Elsevier Ltd. All rights reserved.

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The structure and size of the eyes generated in numerically simulated tropical cyclones and polar lows have been studied. A primitive-equation numerical model simulated systems in which the structures of the eyes formed were consistent with available observations. Whilst the tropical cyclone eyes generated were usually rapidly rotating, it appeared impossible for an eye formed in a system with a polar environment to develop this type of structure. The polar low eyes were found to be unable to warm through the subsidence of air with high values of potential temperature, as the environment was approximately statically neutral. Factors affecting the size of the eye were investigated through a series of controlled experiments. In mature tropical cyclone systems the size of the eye was insensitive to small changes in initial conditions, surface friction and latent and sensible heating from the ocean. In contrast, the eye size was strongly dependent on these parameters in the mature polar lows. Consistent with the findings, a mechanism is proposed in which the size of the eye in simulated polar lows is controlled by the strength of subsidence within it.

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Molecular phylogenetic hypotheses of species-rich lineages in regions where geological history can be reliably inferred may provide insights into the scale of processes driving diversification. Here we sample all extant or recently extinct white-eye (Zosterops) taxa of the southwest Indian Ocean, combined with samples from all principal continental lineages. Results support a high dispersal capability, with at least two independent continental sources for white-eyes of the region. An early (within 1.8 million years ago) expansion into the Indian Ocean may have originated either from Asia or Africa; the three resulting lineages show a disparate distribution consistent with considerable extinction following their arrival. Africa is supported as the origin of a later expansion into the region (within 1.2 million years ago). On two islands, a pair of Zosterops species derived from independent immigrations into the Indian Ocean co-occur or may have formerly co-occurred, providing strong support for their origin by double-island colonization rather than within-island (sympatric or microallopatric) speciation. On Mauritius and La Reunion, phylogenetic placement of sympatric white-eyes allow us to rule out a scenario in which independent within-island speciation occurred on both islands; one of the species pairs must have arisen by double colonization, while the other pair is likely to have arisen by the same mechanism. Long-distance immigration therefore appears to be responsible for much of the region's white-eye diversity. Independent immigrations into the region have resulted in lineages with mutually exclusive distributions and it seems likely that competition with congeneric species, rather than arrival frequency, may limit present-day diversity.

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Saccadic eye movements and fixations are the behavioral means by which we visually sample text during reading. Human oculomotor control is governed by a complex neurophysiological system involving the brain stem, superior colliculus, and several cortical areas [1, 2]. A very widely held belief among researchers investigating primate vision is that the oculomotor system serves to orient the visual axes of both eyes to fixate the same target point in space. It is argued that such precise positioning of the eyes is necessary to place images on corresponding retinal locations, such that on each fixation a single, nondiplopic, visual representation is perceived [3]. Vision works actively through a continual sampling process involving saccades and fixations [4]. Here we report that during normal reading, the eyes do not always fixate the same letter within a word. We also demonstrate that saccadic targeting is yoked and based on a unified cyclopean percept of a whole word since it is unaffected if different word parts are delivered exclusively to each eye via a dichoptic presentation technique. These two findings together suggest that the visual signal from each eye is fused at a very early stage in the visual pathway, even when the fixation disparity is greater than one character (0.29 deg), and that saccade metrics for each eye are computed on the basis of that fused signal.

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This commentary raises general questions about the parsimony and generalizability of the SIMS model, before interrogating the specific roles that the amygdala and eye contact play in it. Additionally, this situates the SIMS model alongside another model of facial expression processing, with a view to incorporating individual differences in emotion perception.

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This article is a close analysis of The Cry of the Owl (Thraves, 2009). It is also part of larger project to bring together traditions of detailed criticism with those of production history, which culminates in second article on the film due to be published in 2011. The detail of the argument concerns analysing a range of the film’s key signifying systems, with a particular interest in the way the film explores the gap between images / impressions and characters’ realities; engages in a complex way with generic traditions and modes of address; establishes complex patterns of connection and contrast through blocking, camera strategies and narrative structure.

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Perceptual multimedia quality is of paramount importance to the continued take-up and proliferation of multimedia applications: users will not use and pay for applications if they are perceived to be of low quality. Whilst traditionally distributed multimedia quality has been characterised by Quality of Service (QoS) parameters, these neglect the user perspective of the issue of quality. In order to redress this shortcoming, we characterise the user multimedia perspective using the Quality of Perception (QoP) metric, which encompasses not only a user’s satisfaction with the quality of a multimedia presentation, but also his/her ability to analyse, synthesise and assimilate informational content of multimedia. In recognition of the fact that monitoring eye movements offers insights into visual perception, as well as the associated attention mechanisms and cognitive processes, this paper reports on the results of a study investigating the impact of differing multimedia presentation frame rates on user QoP and eye path data. Our results show that provision of higher frame rates, usually assumed to provide better multimedia presentation quality, do not significantly impact upon the median coordinate value of eye path data. Moreover, higher frame rates do not significantly increase level of participant information assimilation, although they do significantly improve overall user enjoyment and quality perception of the multimedia content being shown.

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Although the medieval papacy's stance towards the Jews is a well-established area of research, Jewish ideas about the papacy remain a surprisingly underdeveloped historical topic. This article explores such ideas through the genre of polemic and disputational literature. Jewish writers were keen to ensure the safety of their communities in western Europe and grateful for statements of papal protection. They fully acknowledged that popes had always played and would continue to play an important role in safeguarding their well-being and determining their future. Yet although contemporary and later writers often valued papal protection more highly than that of monarchs, emperors or clergy, they also knew that it had its carefully circumscribed limits. Furthermore, although they were respectful of the papacy's power, both spiritual and temporal, they were dismissive of the scriptural and theological formulations on which Christian claims for apostolic authority rested and highly critical of Christian beliefs about the papacy, in particular that of apostolic succession. Jewish ideas about both individual popes and the medieval papacy as an institution are therefore nuanced and complex; they deserve rigorous and wide-ranging investigation and it is hoped that this article will contribute to their better understanding.

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