1,721,078 research outputs found
Capitalisme sous-développé et aménagement de l'espace : le Pérou, 1920-1940
No full textSlater David. Capitalisme sous-développé et aménagement de l'espace : le Pérou, 1920-1940. In: Tiers-Monde, tome 16, n°64, 1975. pp. 707-734
Surface science studies of catalytic promotors on Cu(110)
No full textSurface science studies of both clean and modified Cu(110) surfaces utilising R.A.I.R.S., T.P.D., L.E.E.D., E.E.L.S. and Δφ measurements have been employed to assess the effects of pre-adsorbed alkali metal adatoms and surface defects on the adsorption of CO and H_3COH. CO adsorption on the clean surface exhibits an interesting coverage dependent behaviour of the R.A.I.R.S. absorption band in which the intensity of this band is observed to decrease with increasing CO coverage after the completion of a (2x1) CO adlayer. T.P.D. measurements show that this decrease is associated with the operation of strong lateral CO-CO repulsive interactions at high Co coverage and is ascribed to a tilting of the CO species away from the surface normal to minimise such interactions. For the adsorption of CO on Potassium pre-dosed surfaces a variety of perturbed CO species are observed. The nature of the species present is found to be strongly dependent on the precise coverage of Potassium present. At low alkali metal coverages the observed behaviour is interpreted in terms of the formation of ordered K/CO islands in which the CO is bound to Cu atoms and perturbed by the presence of nearby Potassium. R.A.I.R.S. measurements of Co adsorbed on relatively K free regions of the surface between such islands provides evidence for a similar though much weaker K/CO interaction at greater K-CO separation. At higher K coverages the extremely strongly perturbed CO species previously attributed to the formation of K/CO complexes are observed. In addition a more weakly bound species is observed. No vibrational features corresponding to the presence of this species have been identified by E.E.L.S. or R.A.I.R.S. which strongly implies a CO species either `lying down' at the surface or strongly screened by the presence of other surface species. Previous investigations regarding the oxidation of methanol on oxygen pre-covered Cu(110) surfaces have provided evidence for the existence of a minor reaction pathway for the formation of surface formate species. On a Cu(110) surface exhibiting regular monatomic steps this process dominates the observed behaviour and is interpreted in terms of an enhanced reactivity of the surface towards the oxidation of methoxy species at surface defect sites.</p
Using a bubble to alleviate post implantation hearing loss – a new model of the cochlea
No full textTitle: post-implantation reduction of residual acoustic hearing due to round window stiffening, and its alleviation with a bubble inside the cochlea implant.Aim: the aim is to improve the quality of life of patients with a cochlea implant, by explaining the cause of their impairment of acoustic hearing and proposing a remedy. Preservation of low frequency hearing allows access to low frequency speech cues, which have been found to enhance speech perception in noise, music perception and perception of supra-segmental features of speech. To achieve this, a suitable finite element model of the cochlea is to be developed, validated and made available to others to facilitate implementation of the proposed remedy.Method: a cochlear implant is normally inserted through the round window, which becomes stiffened because the flexible area is reduced. This stiffening is often exacerbated by the formation of callous tissue on the round window around the implant. The function of the round window is to release the pressure in the cochlear fluid that is caused by the action of the stapes and the oval window; the pressure release allows movement of the almost incompressible fluid from the stapes to the round window, via the basilar membrane where the auditory nerve is stimulated. To replicate this effect of the implant on the acoustic velocity of the basilar membrane, a new finite element model has been developed to accommodate significantly different physiology for the upper and lower chambers.The model has also simulated the effect of including a bubble within the implant, to act as a pressure-release, and hence a remedy.Results: the new model has been validated by comparing the simulation results with the average measured acoustic hearing loss in 105 patients; the simulated and measured results agree within 5 decibels. When a cochlea with normal hearing is modelled, the frequency dependent locations of maximum vibration of the basilar membrane agree, again within 5 dB of those measured and recorded in the literature. The new model shows that the ideal position for the bubble is as close as possible to the round window; however, precise proximity may not be achievable in practice. The length, stiffness and position of the bubble can be input easily to the model, and so the model can be used to predict the performance resulting from practically possible implantation, where the bubble needs to be a small distance from the round window.Conclusion: a two-chamber finite element model of the cochlea has been developed that can be used to predict acoustic hearing loss caused by implantation (other than by inadvertent damage of tissue). The model has been validated by comparison of its results with those of measurements of hearing loss. The model has also been used to show that such loss of hearing can be alleviated by manufacturing the implant so that it contains a small bubble, to be located about 1 mm from the round window. Preservation of low frequency acoustic hearing will be valuable to more patients, now that the NICE criteria have been relaxed in accordance with BCIG recommendations.</p
Modelling the effect of implants and intracochlear excitation on cochlear mechanics
No full textTo help with the design of remedies for the preservation of acoustic hearing for cochlear implant patients, a two chamber finite element model has been developed. The model has been used to quantify the hearing loss that would result from the mechanical stiffening of the round window that is expected to occur as a result of inserting an implant into the scala tympani. Each element or collection of elements of the model can contain an additional compliance to replace that lost from the round window. Each element can also contain an excitation source to emulate an intracochlear actuator for use as part of an electro-acoustic stimulation system. The results of the new model compare closely with those of two established models: one single chamber and one two chamber model, and it enables simulation of the effects of inserting an implant on the mechanics of the cochlea. It has been shown that an achievable bubble could compensate for virtually all of the hearing loss caused by the stiffening of the round window by implantation. It has also been shown that if an actuator could be manufactured that would fit in an implant, it would restore acoustic hearing for frequencies between 100 Hz and 1 kHz. Various actuator technologies have been explored to assess their fundamental capability to meet the required acoustic output when scaled down to an acceptable size to fit in an imp
Weep not for the roses [music] : song /
No full textL.1102a (Publisher number). Cover title.; "No. 1 in B-flat".; For voice and piano.; Pl. no.: L.1102a; Also available online http://nla.gov.au/nla.mus-an21399315
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Exploratory findings in virtual induced agency for phantom limb pain
No full textPurpose: Phantom limb pain is chronic and intractable. Recently, virtual reality (VR) and motion capture technology has replicated the mirror box device of Ramachandran (Ramachandran et al. Nature 1995, 377, 489-490; Ramachandran and Rogers-Ramachandran Proc R Soc Biol Sci 1996, 263, 377-386) and led to reductions in this pain. We present results from a novel variation on this method which captures motion data directly from a patient's stump (rather than using the opposite remaining limb) and then transforms it into goal directed, virtual action enacted by an avatar in a VR environment. Method: A sample of subjects with 'arm' (n = 7) and 'leg' (n = 7) amputations underwent trials of a virtual reality (VR) system, controlled by motion captured from their stump which was translated into movements of a virtual limb within the VR environment. Measures of pain in the phantom limb were elicited from patients before and during this exercise as they attempted to gain agency for the movement they saw, and feel embodied within the limb. After this each subject was interviewed about their experiences. Results: Five subjects in each group felt the virtual limb to be moved by them and felt sensations of movement within it. With this they also reported reductions in their phantom limb pain greater than expected from distraction alone. No carry over effect was seen. Conclusions: This technique, which has shown similar success rates to trials of a virtual mirror box, is relatively cheap and portable, and will allow further trials in a home environment
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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