Thesis (Ph.D.) - University of Glasgow, 2002. / Ph.D. thesis submitted to the Department of Psychology, University of Glasgow, 2002. Includes bibliographical references. Print version also available.

Thesis (Ph.D.)--University of Western Australia, 2007.

Thesis (M. S.)--Psychology, Georgia Institute of Technology, 2006. / Corballis, Paul, Committee Member ; Engle, Randall, Committee Chair ; Spieler, Daniel, Committee Member.

Thesis (Ph. D.) -- McMaster University, 1997. / Includes bibliographical references (leaves 91-102). Also available via World Wide Web.

The aim of this thesis was to investigate how visual information is organised in perceptual short term memory, with special interest in colour, spatial frequency and velocity. Previous studies of VSTM have indicated the existence of specific memory mechanisms for visual attributes such as orientation, spatial frequency, velocity, contrast and colour. The retention of information in visual short term memory for these basic visual attributes can be disrupted by the presentation of masking stimuli during inter-stimulus intervals (ISIs), which are outside the range of traditional sensory masking. We exploited this memory masking effect in order to examine the organisation of visual information in VSTM. Four groups of experiments were conducted in which participants carried out a delayed discrimination paradigm that employed a two-alternative forced choice (2-AFC) procedure in conjunction with a method of constant stimuli. The fidelity of VSTM was measured by performance markers such as discrimination thresholds and point of subjective equalities. We have found selective memory masking effects, which serve as further evidence in favour of the modular organisation in VSTM, namely, that human visual perceptual memory is based upon multiple, tuned channels in case of colour, spatial frequency and speed, similar to those found in the earliest stages of visual processing for spatial frequency. Moreover, each of these storage mechanisms are tuned to a relatively narrow range of stimulus parameters that are closely linked to visual discrimination mechanisms. These findings add further support to the view that low-level sensory processing mechanisms form the basis for the retention of colour, spatial frequency and velocity information in perceptual memory. We also found evidence for the broad range of transfer of memory masking effects across spatial location, which indicates more long range, long duration interactions between channels that are likely to rely upon contributions from neural processes located in higher visual areas. In conclusion, the experiments presented in this thesis provide significant insight into the organization of visual information in perceptual short term memory.

Thesis (Ph.D.)--University of Arizona, 2002. / Includes bibliographical references (leaves 187-190).

Esta dissertação é um estudo exploratório sobre o processo de mediação e apropriação cultural de informação em um contexto social, marcado historicamente pela expropriação cultural - Cambury - uma comunidade rural formada por pescadores e quilombolas que vivem na Mata Atlântica. A análise de campo e as reflexões teóricas se debruçaram sobre o papel do mediador e dos dispositivos informacionais, tendo como referência metodológica a pedagogia dialógica das Oficinas de Memória, espaço privilegiado para experimentação de saberes, trocas culturais e simbólicas. Como resultado, formulamos categorias significativas de análise do mediador cultural, cujo amálgama de saberes (informacionais; procedimentais e atitudinais) julgamos indispensável aos processos de significação em territórios simbólicos diferenciados. Como produto de conhecimento no campo da pesquisa social aplicada, criamos o dispositivo infoeducativo - Estação Memória Cambury - conjugado à interface de comunicação digital; e desenvolvemos referenciais teóricos e metodológicos que podem contribuir em futuras práticas infoeducativas que favoreçam a produção, circulação e apropriação social de saberes com os sujeitos do saber, confrontando-os com a questão do sentido da vida, do mundo e de si mesmos. / This dissertation is an exploratory study about the mediation process and cultural appropriation of information in a social context which is historically marked by the cultural expropriation - Cambury - a rural community formed by fishermen and other native citizens living nowadays in the Atlantic Forest. The field analysis and the theoretical reflections are based on the role of the mediator and on informational devices. As methodological reference we have the dialogical pedagogy collected from Oficinas de Memória (Workshops of Memory), a privileged space for experimentation of knowledge, cultural and symbolic trading. As a result, we have elaborated important analytical categories for the cultural mediator whose amalgam of knowledge (informational, procedural and attitudinal) is indispensable to the processes of meaningfulness in differentiated symbolic territories. The output in the field of practical social research, is nevertheless the creation of an info-educative device - Estação Memória Cambury - (Cambury Memory Station) - linked to digital communication interface. Finally, methodological and theoretical references have also been developed to possibly contribute in further info-educative practices to enable social production, circulation and knowledge basis together with the subjects of the referred basis, confronting people with life; the meaning of life and of the world and themselves amongst it all.

Esta dissertação é um estudo exploratório sobre o processo de mediação e apropriação cultural de informação em um contexto social, marcado historicamente pela expropriação cultural - Cambury - uma comunidade rural formada por pescadores e quilombolas que vivem na Mata Atlântica. A análise de campo e as reflexões teóricas se debruçaram sobre o papel do mediador e dos dispositivos informacionais, tendo como referência metodológica a pedagogia dialógica das Oficinas de Memória, espaço privilegiado para experimentação de saberes, trocas culturais e simbólicas. Como resultado, formulamos categorias significativas de análise do mediador cultural, cujo amálgama de saberes (informacionais; procedimentais e atitudinais) julgamos indispensável aos processos de significação em territórios simbólicos diferenciados. Como produto de conhecimento no campo da pesquisa social aplicada, criamos o dispositivo infoeducativo - Estação Memória Cambury - conjugado à interface de comunicação digital; e desenvolvemos referenciais teóricos e metodológicos que podem contribuir em futuras práticas infoeducativas que favoreçam a produção, circulação e apropriação social de saberes com os sujeitos do saber, confrontando-os com a questão do sentido da vida, do mundo e de si mesmos. / This dissertation is an exploratory study about the mediation process and cultural appropriation of information in a social context which is historically marked by the cultural expropriation - Cambury - a rural community formed by fishermen and other native citizens living nowadays in the Atlantic Forest. The field analysis and the theoretical reflections are based on the role of the mediator and on informational devices. As methodological reference we have the dialogical pedagogy collected from Oficinas de Memória (Workshops of Memory), a privileged space for experimentation of knowledge, cultural and symbolic trading. As a result, we have elaborated important analytical categories for the cultural mediator whose amalgam of knowledge (informational, procedural and attitudinal) is indispensable to the processes of meaningfulness in differentiated symbolic territories. The output in the field of practical social research, is nevertheless the creation of an info-educative device - Estação Memória Cambury - (Cambury Memory Station) - linked to digital communication interface. Finally, methodological and theoretical references have also been developed to possibly contribute in further info-educative practices to enable social production, circulation and knowledge basis together with the subjects of the referred basis, confronting people with life; the meaning of life and of the world and themselves amongst it all.

Quantum memories are key components in photonics-based quantum information processing networks. Their ability to store and retrieve information on demand makes repeat-until-success strategies scalable. Warm alkali-metal vapours are interesting candidates for the implementation of such memories, thanks to their very long storage times as well as their experimental simplicity and versatility. Operation with the Raman memory protocol enables high time-bandwidth products, which denote the number of possible storage trials within the memory lifetime. Since large time-bandwidth products enable multiple synchronisation trials of probabilistically operating quantum gates via memory-based temporal multiplexing, the Raman memory is a promising tool for such tasks. Particularly, the broad spectral bandwidth allows for direct and technologically simple interfacing with other photonic primitives, such as heralded single photon sources. Here, this kind of light-matter interface is implemented using a warm caesium vapour Raman memory. Firstly, we study the storage of polarisation-encoded quantum information, a common standard in quantum information processing. High quality polarisation preservation for bright coherent state input signals can be achieved, when operating the Raman memory in a dual-rail configuration inside a polarisation interferometer. Secondly, heralded single photons are stored in the memory. To this end, the memory is operated on-demand by feed-forward of source heralding events, which constitutes a key technological capability for applications in temporal multiplexing. Prior to storage, single photons are produced in a waveguide-based spontaneous parametric down conversion source, whose bespoke design spectrally tailors the heralded photons to the memory acceptance bandwidth. The faithful retrieval of stored single photons is found to be currently limited by noise in the memory, with a signal-to-noise ratio of approximately 0.3 in the memory output. Nevertheless, a clear influence of the quantum nature of an input photon is observed in the retrieved light by measuring the read-out signal's photon statistics via the g⁽²⁾-autocorrelation function. Here, we find a drop in g⁽²⁾ by more than three standard deviations, from g⁽²⁾ ~ 1.69 to g⁽²⁾ ~ 1.59 upon changing the input signal from coherent states to heralded single photons. Finally, the memory noise processes and their scalings with the experimental parameters are examined in detail. Four-wave-mixing noise is determined as the sole important noise source for the Raman memory. These experimental results and their theoretical description point towards practical solutions for noise-free operation.