Detection of purkinje images for automatic positioning of fixation target and interferometric measurements of anterior eye chamber

In cataract surgery, the eye���s natural lens is removed because it has gone opaque and doesn���t allow clear vision any longer. To maintain the eye���s optical power, a new artificial lens must be inserted. Called Intraocular Lens (IOL), it needs to be modelled in order to have the correct refractive power to substitute the natural lens. Calculating the refractive power of this substitution lens requires precise anterior eye chamber measurements. An interferometry equipment, the AC Master from Zeiss Meditec, AG, was in use for half a year to perform these measurements. A Low Coherence Interferometry (LCI) measurement beam is aligned with the eye���s optical axis, for precise measurements of anterior eye chamber distances. The eye follows a fixation target in order to make the visual axis align with the optical axis. Performance problems occurred, however, at this step. Therefore, there was a necessity to develop a new procedure that ensures better alignment between the eye���s visual and optical axes, allowing a more user friendly and versatile procedure, and eventually automatizing the whole process. With this instrument, the alignment between the eye���s optical and visual axes is detected when Purkinje reflections I and III are overlapped, as the eye follows a fixation target. In this project, image analysis is used to detect these Purkinje reflections��� positions, eventually automatically detecting when they overlap. Automatic detection of the third Purkinje reflection of an eye following a fixation target is possible with some restrictions. Each pair of detected third Purkinje reflections is used in automatically calculating an acceptable starting position for the fixation target, required for precise measurements of anterior eye chamber distances.

Evaluation of air lime and clayish earth mortars for earthen wall renders

CIAV2013 ��� International Conference on Vernacular Architecture, 7�� ATP, VerSus, 16-20 october 2013

On and off air: an ethnographic exploration of minority radio in Portugal

Taking a Media Anthropology���s approach to dynamics of mediated selfrepresentation in migratory contexts, this thesis starts by mapping radio initiatives produced by, for and/or with migrants in Portugal. To further explore dynamics of support of initial settlement in the country, community-making, cultural reproduction, and transnational connectivity - found both in the mapping stage and the minority media literature (e.g. Kosnick, 2007; Rigoni & Saitta, 2012; Silverstone & Georgiou, 2005) - a case study was selected: the station awarded with the first bilingual license in Portugal. The station in question caters largely to the British population presenting themselves as ���expats��� and residing in the Algarve. The ethnographic strategy to research it consisted of ���following the radio��� (Marcus, 1995) beyond the station and into the events and establishments it announces on air, so as to relate production and consumption realms. The leading research question asks how does locally produced radio play into ���expats��� processes of management of cultural identity ��� and what are the specificities of its role? Drawing on conceptualizations of lifestyle migration (Benson & O���Reilly, 2009), production of locality (Appadurai 1996) and the public sphere (Butsch, 2007; Calhoun & et al, 1992; Dahlgren, 2006), this thesis contributes to valuing radio as a productive gateway to research migrants��� construction of belonging, to inscribe a counterpoint in the field of minority media, and to debate conceptualizations of migratory categories and flows. Specifically, this thesis argues that the station fulfills similar roles to other minority radio initiatives but in ways that are specific to the population being catered to. Namely, unlike other minority stations, radio facilitates the process of transitioning between categories along on a continuum linking tourists and migrants. It also reflects and participates in strategies of reterritorialization that rest on functional and partial modes of incorporation. While contributing to sustain a translocality (Appadurai, 1996) it indexes and fosters a stance of connection that is symbolically and materially connected to the UK and other ���neighborhoods��� but is, simultaneously, oriented to engaging with the Algarve as ���home���. Yet, besides reifying a British cultural identity, radio���s oral, repetitive and ephemeral discourse particularly trivializes the reproduction of an ambivalent stance of connection with place that is shared by other ���expats���. This dynamic is related to migratory projects driven by social imaginaries fostered by international media that stimulate the search for idealized ways of living, which the radio associates with the Algarve. While recurrently localizing and validating the narrative projecting an idealized ���good life���, radio amplifies dynamics among migrants that seem to reaffirm the migratory move as a good choice.