875 resultados para Reflexive vasodilation


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PURPOSE. To investigate the effect of age on optokinetic nystagmus (OKN) in response to stimuli designed to preferentially stimulate the M-pathway. METHOD. OKN was recorded in 10 younger (32.3 +/- 5.98 years) and 10 older (65.6 +/- 6.53) subjects with normal vision. Vertical gratings of 0.43 or 1.08 cpd drifting at 5 degrees/s or 20 degrees/s and presented at either 8% or 80% contrast were displayed on a large screen as full-field stimulation, central stimulation within a central Gaussian-blurred window of 15 diameter, or peripheral stimulation outside this window. All conditions apart from the high-contrast condition were presented in a random order at two light levels, mesopic (1.8 cdm(-2)) and photopic (71.5 cdm(-2)). RESULTS. Partial-field data indicated that central stimulation, mesopic light levels, and lower temporal frequency each significantly increased slow-phase velocity (SPV). Although there was no overall difference between groups for partial-field stimulation, full-field stimulation, or low-contrast stimulation, a change in illumination revealed a significant interaction with age: there was a larger decrease in SPV going from photopic to mesopic conditions for the older group than the younger group, especially for higher temporal frequency stimulation. CONCLUSIONS. OKN becomes reflexive in conditions conducive to M-pathway stimulation, and this rOKN response is significantly diminished in older healthy adults than in younger healthy adults, indicative of decreased M-pathway sensitivity.

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We recorded reflexive OKN in ten younger (32.3±5.98 years) and older (65.6±6.53) visually normal subjects under viewing conditions designed to differentiate M-pathway functioning from other pathways. Subjects were required to gaze straight ahead while viewing vertical gratings of either 0.43 or 1.08 cpd, drifting at either 5 or 20°/sec and presented at either 8 or 80% contrast. Gratings were presented as full field stimulation, central stimulation or peripheral (>15°) stimulation. The order of presentation of conditions was pseudo-randomised at two blocked light levels: ‘mesopic’ or twilight conditions (1.8 cdm-2) and ‘photopic’ or full light conditions (71.5 cdm-2). For the partial fields, central stimulation, mesopic light level, lower temporal frequencies (i.e. number of stripes passing per second) each contributed to greater OKN strength as measured by slow-phase velocity (SPV). For full field stimulation, and especially for higher temporal frequencies and low contrast, there was a significant interaction between age group × light level (p = 0.017): SPV diminished much more among the older than the younger group for the twilight condition compared to full light. Such a clear diminution in M-pathway sensitivity revealed by OKN response has important implications for everyday situations like crash avoidance under twilight driving conditions.

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Continuing Professional Development (CPD) is seen as a vital part of a professional engineer’s career, by professional engineering institutions as well as individual engineers. Factors such as ever-changing workforce requirements and rapid technological change have resulted in engineers no longer being able to rely just on the skills they learnt at university or can pick up on the job; they must undergo a structured professional development with clear objectives to develop further professional knowledge, values and skills. This paper presents a course developed for students undertaking a Master of Engineering or Master of Project Management at the University of Queensland. This course was specifically designed to help students plan their continuing professional development, while developing professional skills such as communication, ethical reasoning, critical judgement and the need for sustainable development. The course utilised a work integrated learning pedagogy applied within a formal learning environment, and followed the competency based chartered membership program of Engineers Australia, the peak professional body of engineers in Australia. The course was developed and analysed using an action learning approach. The main research question was “Can extra teaching and learning activities be developed that will simulate workplace learning?” The students continually assessed and reflected upon their current competencies, skills and abilities, and planed for the future attainment of specific competencies which they identified as important to their future careers. Various evaluation methods, including surveys before and after the course, were used to evaluate the action learning intervention. It was found that the assessment developed for the course was one of the most important factors, not only in driving student learning, as is widely accepted, but also in changing the students’ understandings and acceptance of the need for continuous professional development. The students also felt that the knowledge, values and skills they developed would be beneficial for their future careers, as they were developed within the context of their own professional development, rather than to just get through the course. © 2005, American Society for Engineering Education

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* This paper was supported in part by the Bulgarian Ministry of Education, Science and Technologies under contract MM-506/95.

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Urban ethnographic studies in social science usually proceed from within a pre-figured research framework that guides field activity and filters what is considered see-worthy and study-worthy to those phenomena which are in some way necessary for the fulfillment of specific research agendas. Reliance on formalized ethnographic research methods to explore the city, and the reflex to intellectualize that which is observed by using them, frequently leads to the neglect of much of what comprises the ethnographic richness of city-life through an overly-contemplative intellectuocentrism. ^ Flânerie, an avocational, proto-sociological ethnographic mode of urban exploration and observation originating in early-nineteenth-century Paris, is representative of an alternate approach to exploration and study of the city—one less subject to a compressed horizon of ethnographic experience. It affords insight into a broad range of phenomena taking place in interstitial urban space and time which often escape the instrumentally overly-determined gaze of professionalist research inquiry. ^ The present work addressed the fact that the concept of flânerie , though occasionally invoked in discussions of methodology in urban sociology and cultural studies, had not been subjected to a systematic attempt to relate it to the research methods of these disciplines. Though as a typological figure the flâneur is thought to have disappeared long ago, practices represented by the concept continue to be engaged in by persons inside and outside of academia who approach city life and social science with a perspective somewhat transcending the reified dichotomies of private-professional and art-and-science. This study transferred aspects of the experience of the city embodied in the flâneur to the realm of ethnographic urban studies and the building of grounded social theory, finding flânerie to be crucial to the development of a refined knowledge of urban life, and an important means by which previously overlooked social phenomena and silenced avenues of research inquiry might be exposed. ^ The conclusions reached found a “flâneuristic” approach to the city as being beneficial to research practice and the vitalization of urban ethnographic inquiry, by affording opportunities for exposure to, and immersion within, an expanded range of quotidian social phenomena that have frequently escaped the academicist gaze. ^

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In this article we analyse the emergence of Internet activity addressing the experiences of young people in two British communities: South Asian and Chinese.We focus on two web sites: www.barficulture.com and www.britishbornchinese.org.uk, drawing on interviews with site editors, content analysis of the discussion forums, and E-mail exchanges with site users. Our analysis of these two web sites shows how collective identities still matter, being redefined rather than erased by online interaction. We understand the site content through the notion of reflexive racialisation. We use this term to modify the stress given to individualisation in accounts of reflexive modernisation. In addition we question the allocation of racialised meaning from above implied by the concept of racialisation. Internet discussion forums can act as witnesses to social inequalities and through sharing experiences of racism and marginalisation, an oppositional social perspective may develop. The online exchanges have had offline consequences: social gatherings, charitable donations and campaigns against adverse media representations. These web sites have begun to change the terms of engagement between these ethnic groups and the wider society,and they have considerable potential to develop new forms of social action.

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The purpose of this paper is to explore a number of tensions arising in the presentation of autoethnographical research. The paper provides a reflexive autoethnographical account of undertaking and publically presenting autoethnographical research. The paper problematises the extent and form of disclosure; the voice and representation of the researcher; the difficulties in dealing with sensitive subjects; conflicts between public and private domains; questions of validity; the extent and form of theorisation of autoethnographical narratives; and emotion and performativity in presenting autoethnographical research. The paper provides an analysis of the potential of autoethnography, while exploring the presentational and performative context of academia. © 2011, Emerald Group Publishing Limited.