The contribution of visual information to human brake behaviour

In this study the contribution of visual information to the onset and control of braking in front of a stationary target vehicle was investigated. In a first experiment, participants drove a go-cart along a linear track towards a stationary vehicle, in monocular and binocular conditions. They could start braking from a distance of 4, 7, or 10 metres from the vehicle. In a second experiment, the same braking task was executed under three visual conditions: normal vision, central vision and central vision with restricted peripheral vision. No significant differences between monocular and binocular vision were reported, whereas the restriction of peripheral vision was associated with more reserved brake behaviour. The results are discussed with respect to the functional significance of visual information during braking and related to the theoretical discussion on the exact nature of the information used

A Holistic Vision of the Socio-Legal Terrain

Tamanaha discusses Marc Galanter\u27s holistic vision of the socio-legal terrain. Galanter\u27s socio-legal vision has two central overlapping foci, and he always keeps an eye on each and on their interaction. The first focus is the official state legal system, which he examines from every conceivable angle: who becomes lawyers, how are they trained, how many lawyers are there, what are the circumstances of their work environment, who pays for their services. Galanter also focuses on what they are not doing (intentionally or otherwise), inquiring into the implications and consequences of their inaction. These inquiries extend from the official legal system to engage, encompass, and interact with Galanter\u27s second central focus: the social realm of intercourse and regulation. This social realm, in Galanter\u27s vision, is chock full of a plurality of interacting, overlapping, active regulatory systems of every kind-from religious systems, to corporations, to sports leagues, to the family

Leading From the Middle: Mid-Level District Staff and Instructional Improvement

This three-year research project demonstrates that mid-level central office staff can make or break critical reform initiatives. It also provides strong recommendations for a new vision of leadership in which central office and school staff become equal partners

Orientation Information in Encoding Facial Expressions for People With Central Vision Loss.

Purpose:Patients with central vision loss face daily challenges on performing various visual tasks. Categorizing facial expressions is one of the essential daily activities. The knowledge of what visual information is crucial for facial expression categorization is important to the understanding of the functional performance of these patients. Here we asked how the performance for categorizing facial expressions depends on the spatial information along different orientations for patients with central vision loss. Methods:Eight observers with central vision loss and five age-matched normally sighted observers categorized face images into four expressions: angry, fearful, happy, and sad. An orientation filter (bandwidth = 23°) was applied to restrict the spatial information within the face images, with the center of the filter ranged from horizontal (0°) to 150° in steps of 30°. Face images without filtering were also tested. Results:When the stimulus visibility was matched, observers with central vision loss categorized facial expressions just as well as their normally sighted counterparts, and showed similar confusion and bias patterns. For all four expressions, performance (normalized d'), uncorrelated with any of the observers' visual characteristics, peaked between -30° and 30° filter orientations and declined systematically as the filter orientation approached vertical (90°). Like normally sighted observers, observers with central vision loss also relied mainly on mouth and eye regions to categorize facial expressions. Conclusions:Similar to people with normal vision, people with central vision loss rely primarily on the spatial information around the horizontal orientation, in particular the regions around the mouth and eyes, for recognizing facial expressions

Estimating Sensor Motion from Wide-Field Optical Flow on a Log-Dipolar Sensor

Log-polar image architectures, motivated by the structure of the human visual field, have long been investigated in computer vision for use in estimating motion parameters from an optical flow vector field. Practical problems with this approach have been: (i) dependence on assumed alignment of the visual and motion axes; (ii) sensitivity to occlusion form moving and stationary objects in the central visual field, where much of the numerical sensitivity is concentrated; and (iii) inaccuracy of the log-polar architecture (which is an approximation to the central 20°) for wide-field biological vision. In the present paper, we show that an algorithm based on generalization of the log-polar architecture; termed the log-dipolar sensor, provides a large improvement in performance relative to the usual log-polar sampling. Specifically, our algorithm: (i) is tolerant of large misalignmnet of the optical and motion axes; (ii) is insensitive to significant occlusion by objects of unknown motion; and (iii) represents a more correct analogy to the wide-field structure of human vision. Using the Helmholtz-Hodge decomposition to estimate the optical flow vector field on a log-dipolar sensor, we demonstrate these advantages, using synthetic optical flow maps as well as natural image sequences

Medical management of hereditary optic neuropathies.

Hereditary optic neuropathies are diseases affecting the optic nerve. The most common are mitochondrial hereditary optic neuropathies, i.e., the maternally inherited Leber's hereditary optic neuropathy (LHON) and dominant optic atrophy (DOA). They both share a mitochondrial pathogenesis that leads to the selective loss of retinal ganglion cells and axons, in particular of the papillo-macular bundle. Typically, LHON is characterized by an acute/subacute loss of central vision associated with impairment of color vision and swelling of retinal nerve fibers followed by optic atrophy. DOA, instead, is characterized by a childhood-onset and slowly progressive loss of central vision, worsening over the years, leading to optic atrophy. The diagnostic workup includes neuro-ophthalmologic evaluation and genetic testing of the three most common mitochondrial DNA mutations affecting complex I (11778/ND4, 3460/ND1, and 14484/ND6) for LHON and sequencing of the nuclear gene OPA1 for DOA. Therapeutic strategies are still limited including agents that bypass the complex I defect and exert an antioxidant effect (idebenone). Further strategies are aimed at stimulating compensatory mitochondrial biogenesis. Gene therapy is also a promising avenue that still needs to be validated

Focusing and orienting spatial attention differently modulate crowding in central and peripheral vision

The allocation of attentional resources to a particular location or object in space involves two distinct processes: an orienting process and a focusing process. Indeed, it has been demonstrated that performance of different visual tasks can be improved when a cue, such as a dot, anticipates the position of the target (orienting), or when its dimensions (as in the case of a small square) inform about the size of the attentional window (focusing). Here, we examine the role of these two components of visuo-spatial attention (orienting and focusing) in modulating crowding in peripheral (Experiment 1 and Experiment 3a) and foveal (Experiment 2 and Experiment 3b) vision. The task required to discriminate the orientation of a target letter "T,'' close to acuity threshold, presented with left and right "H'' flankers, as a function of target-flanker distance. Three cue types have been used: a red dot, a small square, and a big square. In peripheral vision (Experiment 1 and Experiment 3a), we found a significant improvement with the red dot and no advantage when a small square was used as a cue. In central vision (Experiment 2 and Experiment 3b), only the small square significantly improved participants' performance, reducing the critical distance needed to recover target identification. Taken together, the results indicate a behavioral dissociation of orienting and focusing attention in their capability of modulating crowding. In particular, we confirmed that orientation of attention can modulate crowding in visual periphery, while we found that focal attention can modulate foveal crowdin

Investigating design issues of context-aware mobile guides for people with visual impairments

While mobile wayfinding systems for visually impaired people offer huge potential, most insufficiently address the differences between visual impairments and contextual environments, and offer very little context-awareness - usability issues of which are vital in supporting independent mobility. Participants experiencing a loss of central vision, loss of peripheral vision, and total vision loss made up three groups. Our multidisciplinary model of context was used to design a user study, which involved asking participants to walk to pre-determined outdoor and indoor landmarks. Significant differences were found between groups relating to information requirements, and the environmental cues encoded and used to orientate and navigate. The study also found differences between indoor and outdoor contexts. It was concluded that what is meaningful to one form of visual impairment is incidental to another. These issues need to be captured and accounted for if wayfinding systems are to be usable