156 resultados para Perceptual Rivalry


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Purpose: To assess the effects of pre-cooling volume on neuromuscular function and performance in free-paced intermittent-sprint exercise in the heat. Methods: Ten male, teamsport athletes completed four randomized trials involving an 85-min free-paced intermittentsprint exercise protocol in 33°C±33% relative humidity. Pre-cooling sessions included whole body (WB), head+hand (HH), head (H) and no cooling (CONT), applied for 20-min pre-exercise and 5-min mid exercise. Maximal voluntary contractions (MVC) were assessed pre- and postintervention and mid- and post-exercise. Exercise performance was assessed with sprint times, % decline and distances covered during free-paced bouts. Measures of core(Tc) and skin (Tsk) temperatures, heart rate, perceptual exertion and thermal stress were monitored throughout. Venous and capillary blood was analyzed for metabolite, muscle damage and inflammatory markers. Results: WB pre-cooling facilitated the maintenance of sprint times during the exercise protocol with reduced % decline (P=0.04). Mean and total hard running distances increased with pre cooling 12% compared to CONT (P<0.05), specifically, WB was 6-7% greater than HH (P=0.02) and H (P=0.001) respectively. No change was evident in mean voluntary or evoked force pre- to post-exercise with WB and HH cooling (P>0.05). WB and HH cooling reduced Tc by 0.1-0.3°C compared to other conditions (P<0.05). WB Tsk was suppressed for the entire session(P=0.001). HR responses following WB cooling were reduced(P=0.05; d=1.07) compared to CONT conditions during exercise. Conclusion: A relationship between pre-cooling volume and exercise performance seems apparent, as larger surface area coverage augmented subsequent free-paced exercise capacity, in conjunction with greater suppression of physiological load. Maintenance of MVC with pre-cooling, despite increased work output suggests the role of centrally-mediated mechanisms in exercise pacing regulation and subsequent performance.

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This study examined the effects of pre-cooling duration on performance and neuromuscular function for self-paced intermittent-sprint shuttle running in the heat. Eight male, team-sport athletes completed two 35-min bouts of intermittent-sprint shuttle running separated by a 15-min recovery on three separate occasions (33°C, 34% relative humidity). Mixed-method pre-cooling was completed for 20 min (COOL20), 10-min (COOL10) or no cooling (CONT) and reapplied for 5-min mid-exercise. Performance was assessed via sprint times, percentage decline and shuttle-running distance covered. Maximal voluntary contractions (MVC), voluntary activation (VA) and evoked twitch properties were recorded pre- and post-intervention and mid- and post-exercise. Core temperature (T c), skin temperature, heart rate, capillary blood metabolites, sweat losses, perceptual exertion and thermal stress were monitored throughout. Venous blood draws pre- and post-exercise were analyzed for muscle damage and inflammation markers. Shuttle-running distances covered were increased 5.2 ± 3.3% following COOL20 (P < 0.05), with no differences observed between COOL10 and CONT (P > 0.05). COOL20 aided in the maintenance of mid- and post-exercise MVC (P < 0.05; d > 0.80), despite no conditional differences in VA (P > 0.05). Pre-exercise T c was reduced by 0.15 ± 0.13°C with COOL20 (P < 0.05; d > 1.10), and remained lower throughout both COOL20 and COOL10 compared to CONT (P < 0.05; d > 0.80). Pre-cooling reduced sweat losses by 0.4 ± 0.3 kg (P < 0.02; d > 1.15), with COOL20 0.2 ± 0.4 kg less than COOL10 (P = 0.19; d = 1.01). Increased pre-cooling duration lowered physiological demands during exercise heat stress and facilitated the maintenance of self-paced intermittent-sprint performance in the heat. Importantly, the dose-response interaction of pre-cooling and sustained neuromuscular responses may explain the improved exercise performance in hot conditions.

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This study examined physiological and performance effects of pre-cooling on medium-fast bowling in the heat. Ten, medium-fast bowlers completed two randomised trials involving either cooling (mixed-methods) or control (no cooling) interventions before a 6-over bowling spell in 31.9±2.1°C and 63.5±9.3% relative humidity. Measures included bowling performance (ball speed, accuracy and run-up speeds), physical characteristics (global positioning system monitoring and counter-movement jump height), physiological (heart rate, core temperature, skin temperature and sweat loss), biochemical (serum concentrations of damage, stress and inflammation) and perceptual variables (perceived exertion and thermal sensation). Mean ball speed (114.5±7.1 vs. 114.1±7.2 km · h−1; P = 0.63; d = 0.09), accuracy (43.1±10.6 vs. 44.2±12.5 AU; P = 0.76; d = 0.14) and total run-up speed (19.1±4.1 vs. 19.3±3.8 km · h−1; P = 0.66; d = 0.06) did not differ between pre-cooling and control respectively; however 20-m sprint speed between overs was 5.9±7.3% greater at Over 4 after pre-cooling (P = 0.03; d = 0.75). Pre-cooling reduced skin temperature after the intervention period (P = 0.006; d = 2.28), core temperature and pre-over heart rates throughout (P = 0.01−0.04; d = 0.96−1.74) and sweat loss by 0.4±0.3 kg (P = 0.01; d = 0.34). Mean rating of perceived exertion and thermal sensation were lower during pre-cooling trials (P = 0.004−0.03; d = 0.77−3.13). Despite no observed improvement in bowling performance, pre-cooling maintained between-over sprint speeds and blunted physiological and perceptual demands to ease the thermoregulatory demands of medium-fast bowling in hot conditions.

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This investigation examined physiological and performance effects of cooling on recovery of medium-fast bowlers in the heat. Eight, medium-fast bowlers completed two randomised trials, involving two sessions completed on consecutive days (Session 1: 10-overs and Session 2: 4-overs) in 31 ± 3°C and 55 ± 17% relative humidity. Recovery interventions were administered for 20 min (mixed-method cooling vs. control) after Session 1. Measures included bowling performance (ball speed, accuracy, run-up speeds), physical demands (global positioning system, counter-movement jump), physiological (heart rate, core temperature, skin temperature, sweat loss), biochemical (creatine kinase, C-reactive protein) and perceptual variables (perceived exertion, thermal sensation, muscle soreness). Mean ball speed was higher after cooling in Session 2 (118.9 ± 8.1 vs. 115.5 ± 8.6 km · h−1; P = 0.001; d = 0.67), reducing declines in ball speed between sessions (0.24 vs. −3.18 km · h−1; P = 0.03; d = 1.80). Large effects indicated higher accuracy in Session 2 after cooling (46.0 ± 11.2 vs. 39.4 ± 8.6 arbitrary units [AU]; P = 0.13; d = 0.93) without affecting total run-up speed (19.0 ± 3.1 vs. 19.0 ± 2.5 km · h−1; P = 0.97; d = 0.01). Cooling reduced core temperature, skin temperature and thermal sensation throughout the intervention (P = 0.001–0.05; d = 1.31–5.78) and attenuated creatine kinase (P = 0.04; d = 0.56) and muscle soreness at 24-h (P = 0.03; d = 2.05). Accordingly, mixed-method cooling can reduce thermal strain after a 10-over spell and improve markers of muscular damage and discomfort alongside maintained medium-fast bowling performance on consecutive days in hot conditions.

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Process modeling grammars are used to create models of business processes. In this paper, we discuss how different routing symbol designs affect an individual's ability to comprehend process models. We conduct an experiment with 154 students to ascertain which visual design principles influence process model comprehension. Our findings suggest that design principles related to perceptual discriminability and pop out improve comprehension accuracy. Furthermore, semantic transparency and aesthetic design of symbols lower the perceived difficulty of comprehension. Our results inform important principles about notational design of process modeling grammars and the effective use of process modeling in practice.

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PURPOSE: To explore the experience of couples who continued pregnancy following a diagnosis of serious or lethal fetal anomaly. STUDY DESIGN: Thirty-one male and female participants were recruited from a high-risk maternal–fetal medicine clinic in Washington State. Data were collected using in-depth interviews during pregnancy and after the birth of their baby. Transcribed interviews were thematically analyzed through the phenomenological lens of Merleau-Ponty. FINDINGS: Participants described how time became reconfigured and reconstituted as they tried to compress a lifetime of love for their future child into a limited period. Participants’ concepts of time became distorted and were related to their perceptual lived experience rather than the schedule-filled,regimented, linear clock time that governed the health professionals. CONCLUSION: Living in distorted time may be a mechanism parents use to cope with overwhelming and disorienting feelings when their unborn baby is diagnosed with a fetal anomaly.

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Design and Anthropology challenges conventional thinking regarding the nature of design and creativity, in a way that acknowledges the improvisatory skills and perceptual acuity of people. Combining theoretical investigations and documentation of practice based experiments, it addresses methodological questions concerning the re-conceptualisation of the relation between design and use from both theoretical and practice-based positions. Concerned with what it means to draw 'users' into processes of designing and producing this book emphasises the creativity of design and the emergence of objects in social situations and collaborative endeavours. Organised around the themes of perception and the user-producer, skilled practices of designing and using, and the relation between people and things, the book contains the latest work of researchers from academia and industry, to enhance our understanding of ethnographic practice and develop a research agenda for the emergent field of design anthropology. Drawing together work from anthropologists, philosophers, designers, engineers, scholars of innovation and theatre practitioners, Design and Anthropology will appeal to anthropologists and to those working in the fields of design and innovation, and the philosophy of technology and engineering.

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“Slow Horizon” is comprised of six lenticular panels hung in an even, horizontal sequence. As the viewer moves in front of the work, each panel alternates subtly between two vertical colour gradients. From left to right, the panels move through yellow, orange, magenta and violet to ‘midnight blue’. Together, the coloured panels comprise an abstract horizon line that references the changing nature of light at sunset. The scale, movement and chromatic qualities of the panels also allude to the formal characteristics of the screen technologies that pervade contemporary visual culture. “Slow Horizon” contributes to studies in the field of contemporary art. It is particularly concerned with the relationships between abstraction, colour, signification and perception. Since early Modernity, debates concerning representation and the formal qualities of the picture plane have been fundamental to art practice and theory. These debates have often dovetailed with questions of art’s capacity to generate shifts in thought and perception. Practitioners such as Ellsworth Kelly, James Turrell and Ed Ruscha have variously used block and blended colour to engage in these formal, symbolic and perceptual potentials of colour. Using a practice-led research methodology, “Slow Horizon” furthers this creative inquiry. By conflating the reductive visual logics of abstraction and minimalism with the iconic, romantic evocations of sunset imagery, it questions not only the contemporary relationship between abstraction and image-making, but also art’s ability to create moments of stillness and contemplation in a context significantly shaped by screen technologies. “Slow Horizon” has been exhibited internationally as part of “Supermassive” at LA Louver Gallery, Venice, California in 2013. The exhibition was reviewed in The Los Angeles Times.

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Changing environments present a number of challenges to mobile robots, one of the most significant being mapping and localisation. This problem is particularly significant in vision-based systems where illumination and weather changes can cause feature-based techniques to fail. In many applications only sections of an environment undergo extreme perceptual change. Some range-based sensor mapping approaches exploit this property by combining occasional place recognition with the assumption that odometry is accurate over short periods of time. In this paper, we develop this idea in the visual domain, by using occasional vision-driven loop closures to infer loop closures in nearby locations where visual recognition is difficult due to extreme change. We demonstrate successful map creation in an environment in which change is significant but constrained to one area, where both the vanilla CAT-Graph and a Sum of Absolute Differences matcher fails, use the described techniques to link dissimilar images from matching locations, and test the robustness of the system against false inferences.

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Evidence currently supports the view that intentional interpersonal coordination (IIC) is a self-organizing phenomenon facilitated by visual perception of co-actors in a coordinative coupling (Schmidt, Richardson, Arsenault, & Galantucci, 2007). The present study examines how apparent IIC is achieved in situations where visual information is limited for co-actors in a rowing boat. In paired rowing boats only one of the actors, [bow seat] gets to see the actions of the other [stroke seat]. Thus IIC appears to be facilitated despite the lack of important visual information for the control of the dyad. Adopting a mimetic approach to expert coordination, the present study qualitatively examined the experiences of expert performers (N=9) and coaches (N=4) with respect to how IIC was achieved in paired rowing boats. Themes were explored using inductive content analysis, which led to layered model of control. Rowers and coaches reported the use of multiple perceptual sources in order to achieve IIC. As expected(Kelso, 1995; Schmidt & O’Brien, 1997; Turvey, 1990), rowers in the bow of a pair boat make use of visual information provided by the partner in front of them [stroke]. However, this perceptual information is subordinate to perception Motor Learning and Control S111 of the relationship between the boat hull and water passing beside it. Stroke seat, in the absence of visual information about his/her partner, achieves coordination by picking up information about the lifting or looming of the boat’s stern along with water passage past the hull. In this case it appears that apparent or desired IIC is supported by the perception of extra-personal variables, in this case boat behavior; as this perceptual information source is used by both actors. To conclude, co-actors in two person rowing boats use multiple sources of perceptual information for apparent IIC that changes according to task constraints. Where visual information is restricted IIC is facilitated via extra-personal perceptual information and apparent IIC switches to intentional extra-personal coordination.

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This paper will compare and evaluate the effectiveness of commercial media lobbying and advocacy against public service media in two countries, the United Kingdom and Australia. The paper will focus empirically on the commercial media coverage of public service media issues in these countries (relating to the BBC and ABC respectively) over the period since the election of the Conservative-led Coalition in Britain in June 2010, and the election of the Gillard government in Australia in August 2010. Reference will be made to preceding periods as relevant to an understanding of the current environment. In both countries the main commercial media rival to public service media is News Corp and its associated organisations – News Ltd and Sky News in Australia, and News International and BSkyB in the UK. The paper will examine with analysis of print and online news and commentary content how News Corp outlets have reported and commented on the activities and plans of public service media as the latter have developed and extended their presence on digital TV and online platforms. It will also consider the responses of the ABC and BBC to these interventions. It will consider, thirdly, the responses of Australian and British governments to these debates, and the policy outcomes. This section of the paper will seek to evaluate the trajectory of the policy-public-private dynamic in recent years, and to draw conclusions as to the future direction of policy. Particular attention will be devoted to recent key moments in this unfolding dialogue. In Britain, debates around the efforts of News Corp to take over 100% of BSkyB, both before and after the breaking of the phone-hacking scandal in July 2011; in Australia, the debate around the National Broadband Network and the competitive tender process for ABC World, that country’s public service transnational broadcaster; and other key moments where rivalry between News Corp companies and public service media became mainstream news stories provoking wider public debate. The paper will conclude with recommendations as to how public service media organisations might engage constructively with commercial organisations in the future, including News Corp, and taking into account emerging technological and financial challenges to traditional rationales for public service provision.

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Process modeling grammars are used to create scripts of a business domain that a process-aware information system is intended to support. A key grammatical construct of such grammars is known as a Gateway. A Gateway construct is used to describe scenarios in which the workflow of a process diverges or converges according to relevant conditions. Gateway constructs have been subjected to much academic discussion about their meaning, role and usefulness, and have been linked to both process-modeling errors and process-model understandability. This paper examines perceptual discriminability effects of Gateway constructs on an individual's abilities to interpret process models. We compare two ways of expressing two convergence and divergence patterns – Parallel Split and Simple Merge – implemented in a process modeling grammar. On the basis of an experiment with 98 students, we provide empirical evidence that Gateway constructs aid the interpretation of process models due to a perceptual discriminability effect, especially when models are complex. We discuss the emerging implications for research and practice, in terms of revisions to grammar specifications, guideline development and design choices in process modeling.

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This exhibition showcases the work of Postgraduate Landscape Architecture and final year Undergraduate Civil and Environmental Engineering students in response to issues of sustainability in the Port of Bundaberg. The Port of Bundaberg project site, just north of Bargara, is a complex mix of port facilities, urban development, coastal conservation and agriculture. The project brief was to prepare a range of strategic planning and environmental management options for future urban and infrastructure development in the Port area. Postgraduate Landscape Architecture and final year Undergraduate Civil and Environmental Engineering students worked over one teaching semester with guidance from QUT academics and partner organisations to produce strategic planning, environmental management planning and design options for managing future growth in the area. Specifically, these make recommendations regarding: • Interface between Port lands and residential settlement; • Future residential/urban development; • Transport accessibility and mobility – road, rail, tramway and maritime for personal and freight movement; • Local and regional connectivity - both physical and perceptual- between urban settlements of Port of Bundaberg – Burnett Heads and the surrounding area; • Recreational and tourism development; • Public/private space mix and access; • Ecological conservation assets; • Natural and cultural heritage assets The project process involved three visits to the site by QUT students and staff. The first visit at the project’s commencement included a formal briefing session with project partners the Burnett Mary Regional Group, Port of Brisbane Corporation, and Queensland Department of Local Government and Planning. Formal and informal community engagement facilitated by the Burnett Heads Progress Association also allowed students to gain some understanding of local values. A second visit mid-project involved a ‘Futures Workshop’ with students and community. This enabled the students to gain the benefit of local knowledge and experience in response to their work-in-progress, and to establish priorities for project completion. It strengthened the relationship between the community and the students. A final exhibition, ‘Port of Bundaberg Futures' was held at the Port TAFE Campus upon the completion of the project. The student work exhibited offers a diverse number of alternative options for the future urban development, infrastructure and environmental planning that the partner organisations have used for ongoing consultation.

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The overarching aim of this thesis was to investigate how processes of perception and action emerge under changing informational constraints during performance of multi-articular interceptive actions. Interceptive actions provide unique opportunities to study processes of perception and action in dynamic performance environments. The movement model used to exemplify the functionally coupled relationship between perception and action, from an ecological dynamics perspective, was cricket batting. Ecological dynamics conceptualises the human body as a complex system composed of many interacting sub-systems, and perceptual and motor system degrees of freedom, which leads to the emergence of patterns of behaviour under changing task constraints during performance. The series of studies reported in the Chapters of this doctoral thesis contributed to understanding of human behaviour by providing evidence of key properties of complex systems in human movement systems including self-organisation under constraints and meta-stability. Specifically, the studies: i) demonstrated how movement organisation (action) and visual strategies (perception) of dynamic human behaviour are constrained by changing ecological (especially informational) task constraints; (ii) provided evidence for the importance of representative design in experiments on perception and action; and iii), provided a principled theoretical framework to guide learning design in acquisition of skill in interceptive actions like cricket batting.

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Vision-based SLAM is mostly a solved problem providing clear, sharp images can be obtained. However, in outdoor environments a number of factors such as rough terrain, high speeds and hardware limitations can result in these conditions not being met. High speed transit on rough terrain can lead to image blur and under/over exposure, problems that cannot easily be dealt with using low cost hardware. Furthermore, recently there has been a growth in interest in lifelong autonomy for robots, which brings with it the challenge in outdoor environments of dealing with a moving sun and lack of constant artificial lighting. In this paper, we present a lightweight approach to visual localization and visual odometry that addresses the challenges posed by perceptual change and low cost cameras. The approach combines low resolution imagery with the SLAM algorithm, RatSLAM. We test the system using a cheap consumer camera mounted on a small vehicle in a mixed urban and vegetated environment, at times ranging from dawn to dusk and in conditions ranging from sunny weather to rain. We first show that the system is able to provide reliable mapping and recall over the course of the day and incrementally incorporate new visual scenes from different times into an existing map. We then restrict the system to only learning visual scenes at one time of day, and show that the system is still able to localize and map at other times of day. The results demonstrate the viability of the approach in situations where image quality is poor and environmental or hardware factors preclude the use of visual features.