Testing the channel-based model of duration perception

The channel-based model of duration perception postulates the existence of neural mechanisms that respond selectively to a narrow range of stimulus durations centred on their preferred duration (Heron et al Proceedings of the Royal Society B 279 690–698). In principle the channel-based model could
explain recent reports of adaptation-induced, visual duration compression effects (Johnston et al Current Biology 16 472–479; Curran and Benton Cognition 122 252–257); from this perspective duration compression is a consequence of the adapting stimuli being presented for a longer duration than the test stimuli. In the current experiment observers adapted to a sequence of moving random dot patterns at the same retinal position, each 340ms in duration and separated by a variable (500–1000ms) interval. Following adaptation observers judged the duration of a 600ms test stimulus at the same location. The test stimulus moved in the same, or opposite, direction as the adaptor. Contrary to the channel-based
model’s prediction, test stimulus duration appeared compressed, rather than expanded, when it moved in the same direction as the adaptor. That test stimulus duration was not distorted when moving in the opposite direction further suggests that visual timing mechanisms are influenced by additional neural processing associated with the stimulus being timed.

Change in psychological distress in longer-term oesophageal cancer carers: are clusters of illness perception change a useful determinant?

Objective: This study provides a longitudinal assessment of distress in longer-term oesophageal cancer carers, while examining illness perception schema as a possible determinant of change in distress over time.
Methods: Oesophageal cancer carers (n=171), 48-months post-diagnosis, were assessed at baseline and 12-months later with the Illness Perception Questionnaire-Revised, Cancer Coping Questionnaire, Hospital Anxiety and Depression Scale and Concerns About Recurrence Scale.
Results: Findings report deterioration from normal to probable anxiety in 35.7% of carers and probable depression in 28.7% carers over time. Fear of recurrence remained stable. Changes in control, consequence and cause beliefs were identified as key determinants of a change in psychological morbidity.
Conclusions: Illness beliefs appear to be valuable targets for psychological intervention to improve wellbeing among carers of people with oesophageal cancer.

Health care professionals’ experience, understanding and perception of need of advanced cancer patients with cachexia and their families: The benefits of a dedicated clinic.

Background: Cachexia has been defined as an on-going loss of skeletal muscle mass that cannot be fully reversed by conventional nutritional support. It can be found in up to 80% of patients with advanced cancer and has profound psycho-social consequences for patients and their families. There is a paucity of studies examining the role and experience of healthcare professionals in relation to cachexia and existing studies suggest that professional staff have limited understanding and do not intervene effectively.
Aim: To identify barriers and facilitators to good practice in cachexia care in order to inform future developments in service provision.
Design: An exploratory qualitative study was conducted employing semi-structured interviews with a range of healthcare professionals recruited purposefully from an Australian hospital. Interviews were conducted in private rooms within the hospital.
Setting/participants: A range of healthcare professionals responsible for cancer care were recruited from a large Australian teaching hospital.
Results: Interviews were conducted with 8 healthcare professionals responsible for delivering cancer care. Four themes were identified: formal and informal education, knowledge and understanding, truth telling in cachexia and palliative care, and, a multi-disciplinary approach. Findings show how improved knowledge and understanding across a staff body can lead to improved staff confidence and a willingness to address cancer cachexia and its consequences with patients and their families.
Conclusion: Comparison with previous studies illustrates the importance of improving knowledge and understanding about cachexia and how this can contribute to staff having the skills and experience necessary to address cachexia and provide an improved care experience for patients and carers.

Adapting to time: duration channels do not mediate human time perception

Accurately encoding the duration and temporal order of events is essential for survival and important to everyday activities, from holding conversations to driving in fast flowing traffic. Although there is a growing body of evidence that the timing of brief events (< 1s) is encoded by modality-specific mechanisms, it is not clear how such mechanisms register event duration. One approach gaining traction is a channel-based model; this envisages narrowly-tuned, overlapping timing mechanisms that respond preferentially to different durations. The channel-based model predicts that adapting to a given event duration will result in overestimating and underestimating the duration of longer and shorter events, respectively. We tested the model by having observers judge the duration of a brief (600ms) visual test stimulus following adaptation to longer (860ms) and shorter (340ms) stimulus durations. The channel-based model predicts perceived duration compression of the test stimulus in the former condition and perceived duration expansion in the latter condition. Duration compression occurred in both conditions, suggesting that the channel-based model does not adequately account for perceived duration of visual events.

Estratégias para a valorização do coberto vegetal da Ilha de Porto Santo

No presente trabalho desenvolveram-se estudos visando a valorização do coberto vegetal da Ilha de Porto Santo, através de duas metodologias de investigação complementares: a) preservação e reintrodução na Ilha de uma espécie endémica e em risco do Arquipélago da Madeira (Olea maderensis) e de uma espécie naturalizada (Olea europaea ssp. europaea var. sylvestris), recorrendo para o efeito a técnicas de biotecnologia (micropropagação); b) análise da percepção da comunidade local e visitante sobre o fenómeno da desertificação e a valorização do coberto vegetal bem como a sua aceitação relativamente à aplicação de técnicas de biotecnologia (para micropropagar e reintroduzir espécies de oliveira na Ilha) para minimização do processo de desertificação. A dissertação estrutura-se em quatro partes principais. A Parte I caracteriza a Ilha de Porto Santo em termos geográficos, geológicos, climáticos, sócio-economicos e do uso do solo. Enquadra, ainda, o problema da desertificação, através da caracterização/evolução do coberto vegetal ao longo dos anos. Finalmente apresentam-se os objectivos gerais deste estudo. A Parte II centra-se no desenvolvimento de metodologias no âmbito da biotecnologia vegetal para propagação de espécies de O. maderensis e O. europaea ssp. europaea var. sylvestris. em larga escala. Esta parte está dividida em seis capítulos. O Capítulo II.1 aborda a distribuição geográfica das espécies de oliveira e faz uma revisão bibliográfica dos aspectos mais importantes da micropropagação de oliveira (O. europaea L.), principalmente através da micropropagação por estimulação de gomos axilares. No final deste capítulo apresentam-se os objectivos específicos desta investigação. No Capítulo II.2 faz-se a caracterização genética de genótipos de O. maderensis do Arquipélago da Madeira através da análise da ploidia e do conteúdo em DNA por citometria de fluxo (FCM) e através da detecção de polimorfismos por análise de microssatélites (SSR). Nesta análise usaram-se ainda outros genótipos, nomeadamente: O. europaea ssp. europaea var. sylvestris, O. cerasiformes e O. europaea ssp. europaea var. europaea. Este estudo contribuiu para uma melhor caracterização desta espécie e permitiu a detecção de um nível de ploidia novo no género Olea (tetraploidia). O Capítulo II.3 descreve a optimização das condições de cultura in vitro (e.g. desinfecção, meio de cultura e enraizamento) para propagar e preservar a O. maderensis. Avalia-se ainda a “performance” dos rebentos in vitro (taxas de crescimento, avaliação da aparência das folhas e estudos fisiológicos), de modo a confirmar a optimização das condições de propagação. Neste capítulo define-se um meio novo (OMG) para propagação desta espécie endémica. O Capítulo II.4 descreve dois protocolos de micropropagação e aclimatização de ambas as espécies (O. maderensis e O. europaea ssp. europaea var. sylvestris) e a qualidade das plantas (“true-to-type”) é avaliada através da possível ocorrência de variabilidade genética através de FCM (ploidia) e SSRs. O Capítulo II.5 descreve um protocolo eficiente de aclimatização ao campo de O. maderensis e avalia a “performance” das plantas micropropagadas no campo através da análise de parâmetros fisiológicos durante o processo. O Capítulo II.6 apresenta os estudos em curso relativamente às plantas de O. maderensis em aclimatização no campo, bem como a introdução de plantas micropropagadas num outro local da Ilha com um maior grau de degradação dos solos. Estas estratégias estão a ser aplicadas juntamente com a DRFRAM, no âmbito de programas de florestação em curso. Finalmente é realçada a necessidade de estudos semelhantes com outras espécies nativas. Na Parte III, são apresentados os estudos sobre a percepção da comunidade local relativamente à valorização do coberto vegetal para a minimização dos processos de degradação dos solos/desertificação. A introdução faz o enquadramento teórico sobre o fenómeno da desertificação, particularmente na Ilha de Porto Santo e sobre a percepção social da desertificação. São ainda apresentados os objectivos específicos desta investigação. A metodologia adoptada recorreu à aplicação de inquéritos por questionário à população residente e aos visitantes da Ilha de Porto Santo e ainda a realização de inquéritos por entrevista a algumas entidades e especialistas. Estes estudos permitiram verificar que existe uma nítida consciência da situação de risco da ilha, das medidas tomadas e a tomar e da premência da resolução do problema. Face ao recurso de estratégias alternativas envolvendo biotecnologia, e apesar de existir algum desconhecimento, concluiu-se ainda que a população manifesta aceitação, desde que essas estratégias valorizem o coberto vegetal e, assim, ajudem a combater a degradação biofísica dos solos. Finalmente são apresentadas as conclusões e algumas recomendações. Na Parte IV apresentam-se as conclusões gerais e perspectivas futuras, onde o potencial ambiental destas oliveiras bravas micropropagadas é destacado, bem como é considerado o alargamento da aplicação destas estratégias a outras espécies indígenas em risco, nesta Ilha (e noutros locais). São ainda resumidas as principais visões da população e das entidades e dos especialistas que poderão contribuir para apoiar a elaboração de medidas de mitigação e prevenção no combate ao processo de degradação dos solos/desertificação em curso.

Stakeholder participation in sustainable forest management in fire-prone areas

Os incêndios florestais, associados ao abandono do espaço rural, a pequena propriedade florestal e o desinteresse e o absentismo dos proprietários florestais têm sido apontados como fatores que têm afetado a sustentabilidade das florestas em Portugal. Apesar da formulação de políticas e de instrumentos de planeamento e de gestão florestal para lidar com estes constrangimentos, são ainda escassos os progressos para uma Gestão Florestal Sustentável. A nível internacional e europeu, a participação dos agentes já representa um aspeto-chave no processo de definição e de implementação de estratégias que promovam a multifuncionalidade da floresta, mas também se adeqúem às necessidades e aos interesses dos agentes locais. A temática da tese esteve focada nesta discussão, argumentando que existe uma escassa participação dos agentes nos processos de tomada de decisão relativos ao setor florestal. O principal objetivo da investigação foi o desenvolvimento de uma metodologia participativa para a discussão e negociação de estratégias locais para a Gestão Florestal Sustentável, que maximizem o potencial produtivo e o papel sócio-ambiental das florestas, diminuam o risco de incêndio e promovam o crescente interesse e participação dos agentes locais na gestão florestal. A tese está estruturada em três partes. A primeira parte apresenta uma avaliação do sector florestal nacional, com base numa revisão bibliográfica e numa comparação de indicadores, políticas e instrumentos de planeamento e gestão florestal (Capítulo 2) e com base num estudo de perceção social desenvolvido numa área de estudo localizada na região Centro de Portugal. Este estudo analisa as perceções técnicas (decisores políticos e técnicos) e sociais (proprietários florestais e outros membros da comunidade local) sobre as florestas, a gestão florestal e os incêndios florestais (Capítulo 4). As ‘Zonas de Intervenção Florestal’, enquanto ferramenta recente para a cooperação e organização dos proprietários e produtores florestais, foram também analisadas (Capítulo 3). A segunda parte da tese é dedicada à análise de processos de participação pública, com base numa revisão bibliográfica sobre os benefícios, níveis, abordagens e métodos de participação (Capítulo 5) e numa avaliação de processos de participação pública desenvolvidos em Portugal (Capítulo 6). A terceira parte da tese foca-se no desenho e no teste da metodologia participativa proposta no âmbito desta tese (Capítulo 7) e na formulação de algumas orientações para melhoria dos processos participativos na gestão florestal (Capítulo 8). Os resultados confirmaram a centralidade dos incêndios florestais e dos fatores associados ao contexto socioeconómico (e.g. despovoamento e envelhecimento populacional, absentismo, falta de gestão florestal, estrutura fundiária) como os principais problemas que afetam a floresta na região Centro de Portugal. A organização e cooperação dos proprietários florestais emergiu como solução possível para lidar com estas ameaças e promover a multifuncionalidade da floresta, sendo essencial aumentar o conhecimento e a participação dos agentes nas decisões associadas à floresta. É proposta uma ferramenta para esta participação, centrada no contexto local e facilmente utilizável por todos os agentes. A implementação da metodologia participativa revelou o seu potencial no desenvolvimento de uma participação equitativa e inclusiva dos múltiplos agentes.

Grounding human vocabulary in robot perception through interaction

This thesis addresses the problem of word learning in computational agents. The motivation behind this work lies in the need to support language-based communication between service robots and their human users, as well as grounded reasoning using symbols relevant for the assigned tasks. The research focuses on the problem of grounding human vocabulary in robotic agent’s sensori-motor perception. Words have to be grounded in bodily experiences, which emphasizes the role of appropriate embodiments. On the other hand, language is a cultural product created and acquired through social interactions. This emphasizes the role of society as a source of linguistic input. Taking these aspects into account, an experimental scenario is set up where a human instructor teaches a robotic agent the names of the objects present in a visually shared environment. The agent grounds the names of these objects in visual perception. Word learning is an open-ended problem. Therefore, the learning architecture of the agent will have to be able to acquire words and categories in an openended manner. In this work, four learning architectures were designed that can be used by robotic agents for long-term and open-ended word and category acquisition. The learning methods used in these architectures are designed for incrementally scaling-up to larger sets of words and categories. A novel experimental evaluation methodology, that takes into account the openended nature of word learning, is proposed and applied. This methodology is based on the realization that a robot’s vocabulary will be limited by its discriminatory capacity which, in turn, depends on its sensors and perceptual capabilities. An extensive set of systematic experiments, in multiple experimental settings, was carried out to thoroughly evaluate the described learning approaches. The results indicate that all approaches were able to incrementally acquire new words and categories. Although some of the approaches could not scale-up to larger vocabularies, one approach was shown to learn up to 293 categories, with potential for learning many more.

Spatial hearing and sound perception in musical composition

This thesis explores the possibilities of spatial hearing in relation to sound perception, and presents three acousmatic compositions based on a musical aesthetic that emphasizes this relation in musical discourse. The first important characteristic of these compositions is the exclusive use of sine waves and other time invariant sound signals. Even though these types of sound signals present no variations in time, it is possible to perceive pitch, loudness, and tone color variations as soon as they move in space due to acoustic processes involved in spatial hearing. To emphasize the perception of such variations, this thesis proposes to divide a tone in multiple sound units and spread them in space using several loudspeakers arranged around the listener. In addition to the perception of sound attribute variations, it is also possible to create rhythm and texture variations that depend on how sound units are arranged in space. This strategy permits to overcome the so called "sound surrogacy" implicit in acousmatic music, as it is possible to establish cause-effect relations between sound movement and the perception of sound attribute, rhythm, and texture variations. Another important consequence of using sound fragmentation together with sound spatialization is the possibility to produce diffuse sound fields independently from the levels of reverberation of the room, and to create sound spaces with a certain spatial depth without using any kind of artificial sound delay or reverberation.

Perception and software architecture for mobile robotics

When developing software for autonomous mobile robots, one has to inevitably tackle some kind of perception. Moreover, when dealing with agents that possess some level of reasoning for executing their actions, there is the need to model the environment and the robot internal state in a way that it represents the scenario in which the robot operates. Inserted in the ATRI group, part of the IEETA research unit at Aveiro University, this work uses two of the projects of the group as test bed, particularly in the scenario of robotic soccer with real robots. With the main objective of developing algorithms for sensor and information fusion that could be used e ectively on these teams, several state of the art approaches were studied, implemented and adapted to each of the robot types. Within the MSL RoboCup team CAMBADA, the main focus was the perception of ball and obstacles, with the creation of models capable of providing extended information so that the reasoning of the robot can be ever more e ective. To achieve it, several methodologies were analyzed, implemented, compared and improved. Concerning the ball, an analysis of ltering methodologies for stabilization of its position and estimation of its velocity was performed. Also, with the goal keeper in mind, work has been done to provide it with information of aerial balls. As for obstacles, a new de nition of the way they are perceived by the vision and the type of information provided was created, as well as a methodology for identifying which of the obstacles are team mates. Also, a tracking algorithm was developed, which ultimately assigned each of the obstacles a unique identi er. Associated with the improvement of the obstacles perception, a new algorithm of estimating reactive obstacle avoidance was created. In the context of the SPL RoboCup team Portuguese Team, besides the inevitable adaptation of many of the algorithms already developed for sensor and information fusion and considering that it was recently created, the objective was to create a sustainable software architecture that could be the base for future modular development. The software architecture created is based on a series of di erent processes and the means of communication among them. All processes were created or adapted for the new architecture and a base set of roles and behaviors was de ned during this work to achieve a base functional framework. In terms of perception, the main focus was to de ne a projection model and camera pose extraction that could provide information in metric coordinates. The second main objective was to adapt the CAMBADA localization algorithm to work on the NAO robots, considering all the limitations it presents when comparing to the MSL team, especially in terms of computational resources. A set of support tools were developed or improved in order to support the test and development in both teams. In general, the work developed during this thesis improved the performance of the teams during play and also the e ectiveness of the developers team when in development and test phases.

Editorial: Facing the Other: Novel Theories and Methods in Face Perception Research

The Editorial on the Research Topic: Facing the Other: Novel Theories and Methods in Face Perception Research

More than just a problem with faces: Altered body perception in a group of congenital prosopagnosics

It has been estimated that one out of forty people in the general population suffer from congenital prosopagnosia (CP), a neurodevelopmental disorder characterized by difficulty identifying people by their faces. CP involves impairment in recognising faces, although the perception of non-face stimuli may also be impaired. Given that social interaction does not only depend on face processing, but also the processing of bodies, it is of theoretical importance to ascertain whether CP is also characterised by body perception impairments. Here, we tested eleven CPs and eleven matched control participants on the Body Identity Recognition Task (BIRT), a forced-choice match-to-sample task, using stimuli that require processing of body, not clothing, specific features. Results indicated that the group of CPs was as accurate as controls on the BIRT, which is in line with the lack of body perception complaints by CPs. However the CPs were slower than controls, and when accuracy and response times were combined into inverse efficiency scores (IES), the group of CPs were impaired, suggesting that the CPs could be using more effortful cognitive mechanisms to be as accurate as controls. In conclusion, our findings demonstrate CP may not generally be limited to face processing difficulties, but may also extend to body perception

Brightness perception: one simple model explaines most if not all effects

Few models can explain Mach bands (Pessoa, 1996 Vision Research 36 3205-3227) . Our own employs multiscale line and edge coding by simple and complex cells. Lines are interpreted by Gaussian functions, edges by bipolar, Gaussian-truncated errorfunctions. Widths of these functions are coupled to the scales of the underlying cells and the amplitudes are determined by their responses.

Looking through the eyes of the painter: from visual perception to non-photorealistic rendering

In this paper we present a brief overview of the processing in the primary visual cortex, the multi-scale line/edge and keypoint representations, and a model of brightness perception. This model, which is being extended from 1D to 2D, is based on a symbolic line and edge interpretation: lines are represented by scaled Gaussians and edges by scaled, Gaussian-windowed error functions. We show that this model, in combination with standard techniques from graphics, provides a very fertile basis for non-photorealistic image rendering.

Perception-based painterly rendering: funcionality and interface design

Painterly rendering (non-photorealistic rendering or NPR) aims at translating photographs into paintings with discrete brush strokes, simulating certain techniques (im- or expressionism) and media (oil or watercolour). Recently, our research into visual perception and models of processes in the visual cortex resulted in a new rendering scheme, in which detected lines and edges at different scales are translated into brush strokes of different sizes. In order to prepare a version which is suitable for many users, including children, the design of the interface in terms of window and menu system is very important. Discussions with artists and non-artists led to three design criteria: (1) the interface must reflect the procedures and possibilities that real painters follow and use, (2) it must be based on only one window, and (3) the menu system must be very simple, avoiding a jungle of menus and sub-menus. This paper explains the interface that has been developed.