415 resultados para visual pathways


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Professor Nathan Efron recounts his experience in ‘visual no-man’s land’ – a particularly stressful phase of his ophthalmic journey of retinopexy, cryopexy, vitrectomy and IOL surgery attributed to extreme surgically-induced anisometropia.

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Purpose To explore the effect of small-aperture optics, designed to aid presbyopes by increasing ocular depth-of-focus, on measurements of the visual field. Methods Simple theoretical and ray-tracing models were used to predict the impact of different designs of small-aperture contact lenses or corneal inlays on the proportion of light passing through natural pupils of various diameters as a function of the direction in the visual field. The left eyes of five healthy volunteers were tested using three afocal, hand-painted opaque soft contact lenses (www.davidthomas.com). Two were opaque over a 10 mm diameter but had central clear circular apertures of 1.5 and 3.0 mm in diameter. The third had an annular opaque zone with inner and outer diameters of 1.5 and 4.0 mm, approximately simulating the geometry of the KAMRA inlay (www.acufocus.com). A fourth, clear lens was used for comparison purposes. Visual fields along the horizontal meridian were evaluated up to 50° eccentricity with static automated perimetry (Medmont M700, stimulus Goldmann-size III; www.medmont.com). Results According to ray-tracing, the two lenses with the circular apertures were expected to reduce the relative transmittance of the pupil to zero at specific field angles (around 60° for the conditions of the experimental measurements). In contrast, the annular stop had no effect on the absolute field but relative transmittance was reduced over the central area of the field, the exact effects depending upon the natural pupil diameter. Experimental results broadly agreed with these theoretical expectations. With the 1.5 and 3.0 mm pupils, only minor losses in sensitivity (around 2 dB) in comparison with the clear-lens case occurred across the central 10° radius of field. Beyond this angle, sensitivity losses increased, to reach about 7 dB at the edge of the measured field (50°). The field results with the annular stop showed at most only a slight loss in sensitivity (≤3 dB) across the measured field. Conclusion The present theoretical and experimental results support earlier clinical findings that KAMRA-type annular stops, unlike circular artificial pupils, have only minor effects on measurements of the visual field.

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There is an increased interest in the use of Unmanned Aerial Vehicles for load transportation from environmental remote sensing to construction and parcel delivery. One of the main challenges is accurate control of the load position and trajectory. This paper presents an assessment of real flight trials for the control of an autonomous multi-rotor with a suspended slung load using only visual feedback to determine the load position. This method uses an onboard camera to take advantage of a common visual marker detection algorithm to robustly detect the load location. The load position is calculated using an onboard processor, and transmitted over a wireless network to a ground station integrating MATLAB/SIMULINK and Robotic Operating System (ROS) and a Model Predictive Controller (MPC) to control both the load and the UAV. To evaluate the system performance, the position of the load determined by the visual detection system in real flight is compared with data received by a motion tracking system. The multi-rotor position tracking performance is also analyzed by conducting flight trials using perfect load position data and data obtained only from the visual system. Results show very accurate estimation of the load position (~5% Offset) using only the visual system and demonstrate that the need for an external motion tracking system is not needed for this task.

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AIM To examine the prevalence of dyslexia and Meares–Irlen syndrome (MIS) among female students and determine their level of visual stress in comparison with normal subjects. METHODS A random sample of 450 female medical students of King Saud University Riyadh (age range, 18 - 30 years) responded to a wide range of questions designed to accomplish the aims of this study. The detailed questionnaire consisted of 54 questions with twelve questions enquiring on ocular history and demography of participants while 42 questions were on visual symptoms. Items were categorized into; critical and non-critical questions (CQ and NCQ) and were rated on four point Likert scale. Based on the responses obtained, the subjects were grouped into normal (control), dyslexic with or without MIS (Group 1) and subjects with MIS only (Group 2). Responses were analysed as averages and mean scores were calculated and compared between-groups using one way analysis of variance to evaluate total (TVSS = NCQ + CQ), critical and non-critical visual stress scores. The relationship between categorical variables such as age, handedness and condition were assessed with Chi- Square test. RESULTS The completion rate was 96.8% and majority of the respondents (92%) were normal readers, 2% dyslexic and 6% had MIS. They were age-matched. More than half of the participants had visited an eye care practitioner in the last 2yrs. About 13% were recommended eye exercises and one participant experienced pattern glare. Hand preference was not associated with any condition but Group 1 subjects (3/9, 33%) were significantly more likely to be diagnosed of lazy eye than Group 2 (2/27, 7%) and control (27/414, 5%) subjects. The mean ± SD of TVSS responses were 63 ± 14 but it was 44 ± 9 for CQ and 19 ± 5 for NCQ. Responses from all three variables were normally distributed but the CQ responses were on the average more positive (82%) in Group 2 and less positive (46%) in Group 1 than control. With NCQ, the responses were equally less positive in Group 1 and 2 than control. Group 2 subjects showed significantly higher TVSS (P = 0.002), NCQ (P = 0.006) and CQ (P = 0.008) visual stress scores than control but no difference between Group 1 and control subjects, was observed for all scores (P > 0.05, for all comparisons). CONCLUSION The prevalence of dyslexia and MIS among Saudi female students was 2 and 6%, respectively. Critical questions performed best for assessing visual stress symptoms in dyslexic and MIS subjects. Generally, students with MIS were more sensitive to visual stress than normal students but dyslexics were more likely to present with a lazy eye than MIS and normal readers.

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Evidence has accumulated that rod activation under mesopic and scotopic light levels alters visual perception and performance. Here we review the most recent developments in the measurement of rod and cone contributions to mesopic color perception and temporal processing, with a focus on data measured using the four-primary photostimulator method that independently controls rod and cone excitations. We discuss the findings in the context of rod inputs to the three primary retinogeniculate pathways to understand rod contributions to mesopic vision. Additionally, we present evidence that hue perception is possible under scotopic, pure rod-mediated conditions that involves cortical mechanisms.

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This article argues that an indigenous approach to communication research allows us to re-think academic approaches of engaging in and evaluating participatory communication research. It takes as its case study the Komuniti Tok Piksa project undertaken in the Highlands of Papua New Guinea. The project explores ways in which visual methods when paired with a community action approach embedded within an indigenous framework can be used to facilitate social change through meaningful participation. It involves communities to narrate their experiences in regard to HIV and AIDS and assists them in designing and recording their own messages. Local researchers are trained in using visual tools to facilitate this engagement with the communities.

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This is an updated version of a Cochrane review published in Issue 11, 2013 in the Cochrane Library. In many clinical areas, integrated care pathways are utilised as structured multidisciplinary care plans that detail essential steps in caring for patients with specific clinical problems. In particular, care pathways for the dying have been developed as a model to improve care of patients who are in the last days of life. The care pathways were designed with an aim of ensuring that the most appropriate management occurs at the most appropriate time, and that it is provided by the most appropriate health professional. Since the last update, there have been sustained concerns about the safety of implementing end-of-life care pathways, particularly in the United Kingdom (UK). Therefore, there is a significant need for clinicians and policy makers to be informed about the effects of end-of-life care pathways via a systematic review.

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Background Project archives are becoming increasingly large and complex. On construction projects in particular, the increasing amount of information and the increasing complexity of its structure make searching and exploring information in the project archive challenging and time-consuming. Methods This research investigates a query-driven approach that represents new forms of contextual information to help users understand the set of documents resulting from queries of construction project archives. Specifically, this research extends query-driven interface research by representing three types of contextual information: (1) the temporal context is represented in the form of a timeline to show when each document was created; (2) the search-relevance context shows exactly which of the entered keywords matched each document; and (3) the usage context shows which project participants have accessed or modified a file. Results We implemented and tested these ideas within a prototype query-driven interface we call VisArchive. VisArchive employs a combination of multi-scale and multi-dimensional timelines, color-coded stacked bar charts, additional supporting visual cues and filters to support searching and exploring historical project archives. The timeline-based interface integrates three interactive timelines as focus + context visualizations. Conclusions The feasibility of using these visual design principles is tested in two types of project archives: searching construction project archives of an educational building project and tracking of software defects in the Mozilla Thunderbird project. These case studies demonstrate the applicability, usefulness and generality of the design principles implemented.

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This paper describes a practice-led methodology that combines contemporary art theory and processes, as well as concepts of fan studies to construct a space for the critical and creative exploration of screen culture. The research promotes new possibilities for purposeful creative engagements with the screen, framed through the lens of what I term the digital-bricoleur. This performative, link-making approach documents the complicit tendencies that arise out of my affective relationship with screen culture, mapping out a cultural terrain in which I can creatively and critically ‘play’. The creative exploitation of this improvisational and aleatory activity then forms the creative research outputs. It appropriates and reconfigures content from screen culture, creating digital video installations aimed at engendering new experiences and critical interpretations of screen culture.

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This paper presents a novel crop detection system applied to the challenging task of field sweet pepper (capsicum) detection. The field-grown sweet pepper crop presents several challenges for robotic systems such as the high degree of occlusion and the fact that the crop can have a similar colour to the background (green on green). To overcome these issues, we propose a two-stage system that performs per-pixel segmentation followed by region detection. The output of the segmentation is used to search for highly probable regions and declares these to be sweet pepper. We propose the novel use of the local binary pattern (LBP) to perform crop segmentation. This feature improves the accuracy of crop segmentation from an AUC of 0.10, for previously proposed features, to 0.56. Using the LBP feature as the basis for our two-stage algorithm, we are able to detect 69.2% of field grown sweet peppers in three sites. This is an impressive result given that the average detection accuracy of people viewing the same colour imagery is 66.8%.

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In design studio, sketching or visual thinking is part of processes that assist students to achieve final design solutions. At QUT’s First and Third Year industrial design studio classes we engage in a variety of teaching pedagogies from which we identify ‘Concept Bombs’ as instrumental in the development of students’ visual thinking and reflective design process, and also as a vehicle to foster positive student engagement. In First year studios our Concept Bombs’ consist of 20 minute individual design tasks focusing on rapid development of initial concept designs and free-hand sketching. In Third Year studios we adopt a variety of formats and different timing, combining individual and team based tasks. Our experience and surveys tell us that students value intensive studio activities especially when combined with timely assessment and feedback. While conventional longer-duration design projects are essential for allowing students to engage with the full depth and complexity of the design process, short and intensive design activities introduce variety to the learning experience and enhance student engagement. This paper presents a comparative analysis of First and Third Year students’ Concept Bomb sketches to describe the types of design knowledge embedded in them, a discussion of limitations and opportunities of this pedagogical technique, as well as considerations for future development of studio based tasks of this kind as design pedagogies in the midst of current university education trends.

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The exhibition THIS IS NOT THE WORK surveyed a selection of community-engaged artist projects from different locations around the world, and followed the pathways of women-centred social networks in order to initiate further collaboration and conversation. The projects documented in this exhibition were examples of artists working with women and community in challenging and unpredictable ways, demonstrating feminist sensibilities and a commitment to non-hierarchical and collective structures. Co-curated by the feminist art collective LEVEL, this exhibition project uses the gallery as a conceptual base-camp or frontline rather than a just site of display. The exhibition was developed and presented at The Block, Creative Industries Precinct, Queensland University of Technology in 2014. A co-authored paper about the project 'THIS IS NOT THE WORK – Feminist Collectives, Collaboration and Curating‘ was presented by members of LEVEL at the 'Feminist Curating: Contemporary Art and Feminism Symposium', Sydney College of the Arts, Sydney in October 2014.

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Stone Baby: An Exploration of Affect and Trauma in Visual Art was held at the Block, QUT Creative Industries Precinct on August 27-28, 2014. At the conclusion of my Masters project, this exhibition was a showcase of the outcomes of my material and digital explorations in the form of installation, sculpture and film. My primary motivation can be described as a relational and ethical attempt to find a balance between the erotic and the aggressive. This is experienced in the self as feelings of attraction and repulsion in response to the new and unknown "other". Consequently creative practice is necessarily a complex affair that is experienced as a completely immersive and self-contained psychological space. It is within this space that both physical sensation and raw emotion are able to tangibly and conceptually interact with psychoanalytic theory, and concrete materials video and sound.

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There are emerging data to suggest that microRNAs (miRNAs) have significant roles in regulating the function of normal cells and cancer stem cells (CSCs). This review aims to analyse the roles of miRNAs in the regulation of colon CSCs through their interaction with various signalling pathways. Studies showed a large number of miRNAs that are reported to be deregulated in colon CSCs. However, few of the studies available were able to outline the function of miRNAs in colon CSCs and uncover their signalling pathways. From those miRNAs, which are better described, miR-21 followed by miR-34, miR-200 and miR-215 are the most reported miRNAs to have roles in colon CSC regulation. In particular, miRNAs have been reported to regulate the stemness features of colon CSCs mainly via Wnt/B-catenin and Notch signalling pathways. Additionally, miRNAs have been reported to act on processes involving CSCs through cell cycle regulation genes and epithelial-mesenchymal transition. The relative paucity of data available on the significance of miRNAs in CSCs means that new studies will be of great importance to determine their roles and to identify the signalling pathways through which they operate. Such studies may in future guide further research to target these genes for more effective cancer treatment. miRNAs were shown to regulate the function of cancer stem cells in large bowel cancer by targeting a few key signalling pathways in cells.