951 resultados para Expressió facial


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Participants who were unable to detect familiarity from masked 17 ms faces ([Stone and Valentine, 2004] and [Stone and Valentine, in press-b]) did report a vague, partial visual percept. Two experiments investigated the relative strength of the visual percept generated by famous and unfamiliar faces, using masked 17 ms exposure. Each trial presented simultaneously a famous and an unfamiliar face, one face in LVF and the other in RVF. In one task, participants responded according to which of the faces generated the stronger visual percept, and in the other task, they attempted an explicit familiarity decision. The relative strength of the visual percept of the famous face compared to the unfamiliar face was moderated by response latency and participants’ attitude towards the famous person. There was also an interaction of visual field with response latency, suggesting that the right hemisphere can generate a visual percept differentiating famous from unfamiliar faces more rapidly than the left hemisphere. Participants were at chance in the explicit familiarity decision, confirming the absence of awareness of facial familiarity.

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Diagnosis of developmental or congenital prosopagnosia (CP) involves self-report of everyday face recognition difficulties, which are corroborated with poor performance on behavioural tests. This approach requires accurate self-evaluation. We examine the extent to which typical adults have insight into their face recognition abilities across four studies involving nearly 300 participants. The studies used five tests of face recognition ability: two that tap into the ability to learn and recognise previously unfamiliar faces (the Cambridge Face Memory Test, CFMT, Duchaine & Nakayama, 2006 and a newly devised test based on the CFMT but where the study phases involve watching short movies rather than viewing static faces – the CFMT-Films) and three that tap face matching (Benton Facial Recognition Test, BFRT, Benton, Sivan, Hamsher, Varney, & Spreen, 1983; and two recently devised sequential face matching tests). Self-reported ability was measured with the 15-item Kennerknecht et al. (2008) questionnaire; two single-item questions assessing face recognition ability; and a new 77-item meta-cognition questionnaire). Overall, we find that adults with typical face recognition abilities have only modest insight into their ability to recognise faces on behavioural tests. In a fifth study, we assess self-reported face recognition ability in people with CP and find that some people who expect to perform poorly on behavioural tests of face recognition do indeed perform poorly. However, it is not yet clear whether individuals within this group of poor performers have greater levels of insight (i.e., into their degree of impairment) than those with more typical levels of performance.

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Developmental prosopagnosia (DP) is commonly referred to as ‘face blindness’, a term that implies a perceptual basis to the condition. However, DP presents as a deficit in face recognition and is diagnosed using memory-based tasks. Here, we test face identification ability in six people with DP, who are severely impaired on face memory tasks, using tasks that do not rely on memory. First, we compared DP to control participants on a standardised test of unfamiliar face matching using facial images taken on the same day and under standardised studio conditions (Glasgow Face Matching Test; GFMT). DP participants did not differ from normative accuracy scores on the GFMT. Second, we tested face matching performance on a test created using images that were sourced from the Internet and so vary substantially due to changes in viewing conditions and in a person’s appearance (Local Heroes Test; LHT). DP participants show significantly poorer matching accuracy on the LHT relative to control participants, for both unfamiliar and familiar face matching. Interestingly, this deficit is specific to ‘match’ trials, suggesting that people with DP may have particular difficulty in matching images of the same person that contain natural day-to-day variations in appearance. We discuss these results in the broader context of individual differences in face matching ability.

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Empirical studies concerning face recognition suggest that faces may be stored in memory by a few canonical representations. In cortical area V1 exist double-opponent colour blobs, also simple, complex and end-stopped cells which provide input for a multiscale line/edge representation, keypoints for dynamic routing and saliency maps for Focus-of-Attention. All these combined allow us to segregate faces. Events of different facial views are stored in memory and combined in order to identify the view and recognise the face including facial expression. In this paper we show that with five 2D views and their cortical representations it is possible to determine the left-right and frontal-lateral-profile views and to achieve view-invariant recognition of 3D faces.

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Sujeitos com traumatismo crânio-encefálico (TCE) apresentam frequentemente défices no reconhecimento de emoções, sendo estas dificuldades marcadas principalmente pela existência de uma incapacidade em interpretar pistas não-verbais da emoção. Apesar do reconhecimento de emoções em expressões faciais ser largamente estudado, o mesmo não acontece com o reconhecimento da prosódia emocional e em menor grau com o reconhecimento de emoções pela modalidade audiovisual. A presente investigação utilizou a Florida Affect Battery para examinar o reconhecimento emocional nas modalidades visual, auditiva e audiovisual de 17 sujeitos com TCE (quatro com lesão no hemisfério direito, sete no hemisfério esquerdo e seis com lesão bilateral) e 17 sujeitos sem historial de lesão neurológica. No geral, o grupo TCE apresenta desempenhos inferiores no reconhecimento emocional em comparação com o grupo sem lesão. Um efeito de lateralidade hemisférica no reconhecimento emocional emerge com o grupo esquerdo e bilateral a apresentarem mais dificuldades quando comparados com o grupo sem lesão cerebral. Quando analisado os desempenhos dos sujeitos com TCE, considerando a valência emocional (positiva e negativa), verifica-se que quando a modalidade de apresentação é visual as emoções positivas (i.e. a alegria) são mais facilmente reconhecidas e quando a modalidade de apresentação é auditiva as emoções negativas apresentam uma vantagem no reconhecimento emocional. Adicionalmente, o grupo com lesão á direita apresenta desempenhos inferiores no reconhecimento de emoções positivas, enquanto o grupo esquerdo e bilateral apresenta desempenhos inferiores no reconhecimento de emoções negativas. No global, os resultados não apoiam as teorias da superioridade do hemisfério direito no reconhecimento emocional e nas emoções negativas, sugerindo que o processamento emocional implica uma vasta rede de estruturas neuronais, com envolvimento de ambos os hemisférios.

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Estudos anteriores sugerem que níveis elevados de ansiedade traço estão associados com uma maior capacidade de reconhecer a expressão facial de medo. No entanto a maioria dos estudos têm recorrido a paradigmas visuais de reconhecimento de emoções e permanece em aberto se esta associação entre ansiedade traço e reconhecimento da emoção medo se generaliza a outras modalidades sensoriais. Neste trabalho fomos analisar num grupo de participantes saudáveis a relação entre a ansiedade traço e o reconhecimento de emoções, incluindo o medo, em diferentes modalidades para além da visual. O grupo de participantes foi dividido em dois grupos consoante o nível de ansiedade traço (alta e baixa) e o seu desempenho analisado na realização da Florida Affect Batery (FAB). De acordo com as investigações anteriores, previu-se que os níveis de eficácia no reconhecimento das diferentes emoções difeririam entre os grupos de baixo nível de ansiedade e alto nível de ansiedade.

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Theories of embodied cognition argue that language processing arises not from amodal symbols that redescribe sensorimotor and affective experiences, but from partial simulations (reenactments) of modality-specific states. Recent findings on processing of words and sentences support such a stance emphasizing that the role of the body in the domain of language comprehension should not be overlooked or dismissed. The present research was conducted to extend prior work in two important ways. First, the role of simulation was tested with connected discourse rather than words or sentences presented in isolation. Second, both “online” and “offline” measures of discourse comprehension were taken. In Experiments 1 and 2 participants’ facial postures were manipulated to show that preparing the body for processing of emotion-congruent information improves discourse comprehension. In Experiment 3 the direction of body posture was manipulated to show that implicit properties of simulations, such as spatial dimension or location, are at least somewhat involved in processing of large language segments such as discourse. Finally, in Experiments 4 and 5 participants’ body movement and body posture were manipulated to show that even understanding of language describing metaphorical actions physically impossible to perform involves constructing a sensorimotor simulation of the described event. The major result was that compatibility between embodiment and language strongly modulated performance effectiveness in experiments on simulation of emotion and metaphorical action. The effect of simulation on comprehension of discourse implying spatial dimension was fragile. These findings support an embodied simulation account of cognition suggesting that sensorimotor and affective states are at least partially implicated in “online” and “offline” discourse comprehension.

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Background: Artemisia species pollen represents a major cause of allergy in Central Europe. Variations in the pollen season, the influence of climate variables and the prevalence of pollinosis to it were analyzed in Poznan, in western Poland between 1995 and 2004. Methods: A Hirst volumetric spore trap was used for atmospheric sampling. Pollination date trend analysis and Spearman correlation tests were performed. Skin prick tests (SPT) and allergen specific immunoglobulin (Ig)E antibody measurements were performed in 676 and 524 patients, respectively. Results: The Artemisia species pollen season grew longer due to a clear advance in the starting day and only a slightly earlier end point; the peak day also came slightly earlier. Rainfall in the fi rst fortnight of July highly influenced pollen season severity. Temperature was directly correlated with daily Artemisia species pollen levels; relative humidity was inversely correlated. Twelve percent of patients had a positive SPT reaction to Artemisia species. Their symptoms were rhinitis and conjunctivitis (15%), atopic dermatitis (15%), chronic urticaria (14.3%), bronchial asthma (2.4%), and facial and disseminated dermatitis (1.3%). Elevated specifi c IgE concentrations were detected in the sera of 10.1% of patients. Conclusions: Artemisia species pollen is an important cause of pollinosis in western Poland. Pollen season intensity is highly influenced by rainfall in the previous weeks. Trends towards earlier season starts and longer duration, possibly caused by climate change, may have an impact on the allergic population.

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Face recognition from images or video footage requires a certain level of recorded image quality. This paper derives acceptable bitrates (relating to levels of compression and consequently quality) of footage with human faces, using an industry implementation of the standard H.264/MPEG-4 AVC and the Closed-Circuit Television (CCTV) recording systems on London buses. The London buses application is utilized as a case study for setting up a methodology and implementing suitable data analysis for face recognition from recorded footage, which has been degraded by compression. The majority of CCTV recorders on buses use a proprietary format based on the H.264/MPEG-4 AVC video coding standard, exploiting both spatial and temporal redundancy. Low bitrates are favored in the CCTV industry for saving storage and transmission bandwidth, but they compromise the image usefulness of the recorded imagery. In this context, usefulness is determined by the presence of enough facial information remaining in the compressed image to allow a specialist to recognize a person. The investigation includes four steps: (1) Development of a video dataset representative of typical CCTV bus scenarios. (2) Selection and grouping of video scenes based on local (facial) and global (entire scene) content properties. (3) Psychophysical investigations to identify the key scenes, which are most affected by compression, using an industry implementation of H.264/MPEG-4 AVC. (4) Testing of CCTV recording systems on buses with the key scenes and further psychophysical investigations. The results showed a dependency upon scene content properties. Very dark scenes and scenes with high levels of spatial–temporal busyness were the most challenging to compress, requiring higher bitrates to maintain useful information.

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We present a method for recovering facial shape using an image of a face and a reference model. The zenith angle of the surface normal is recovered directly from the intensities of the image. The azimuth angle of the reference model is then combined with the calculated zenith angle in order to get a new field of surface normals. After integration of the needle map, the recovered surface has the effect of mapped facial features over the reference model. Experiments demonstrate that for the lambertian case, surface recovery is achieved with high accuracy. For non-Lambertian cases, experiments suggest potential for face recognition applications.

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A animação 3D de expressões faciais é uma tarefa complexa, o que aliado ao alto consumo de recursos do próprio hardware, torna o processo extremamente longo. Adicionando duas outras condicionantes, nomeadamente os cada vez mais baixos orçamentos praticados e a rapidez exigida pelos clientes, podem por em causa a sustentabilidade de um projeto de animação. Nesse sentido é necessário reunir esforços e investigar profundamente para tornar a animação 3D acessível a qualquer animador. É importante começar precisamente com softwares grátis, para salvaguardar uma despesa logo à partida, e open source, para qualquer programador poder igualmente dar asas à sua imaginação e qualquer tipo de extensão ou melhoria processual poder ser livremente adicionada. O atual paradigma dos softwares grátis e de código aberto na área de modelação e animação 3D é o Blender 3D e foi tomado como referência para qualquer especificação técnica.

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Thesis submitted in the fulfilment of the requirements for the Degree of Master in Electronic and Telecomunications Engineering

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Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção do grau de Mestre em Ciências da Educação Especialidade Intervenção Precoce

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Introdução: A eficácia e segurança da ciclosporina têm sido demonstradas em patologias inflamatórias dermatológicas, nomeadamente psoríase e eczema, em adultos e crianças. Na idade pediátrica o seu uso é no entanto ainda limitado. Apresentamos três casos clínicos em que a ciclosporina, foi interrompida por aparecimento de complicações. Este trabalho visa alertar para potenciais efeitos secundários da ciclosporina, a fim de evitar utilizações abusivas. Casos clínicos: Foram submetidas a terapêutica com ciclosporina oral duas crianças de quatro e 13 anos de idade com eczema e uma criança de dois anos, com psoríase eritrodérmica. No primeiro caso interrompeu-se terapêutica pelo aparecimento de impétigo ao sexto dia de ciclosporina. Iniciou corticóides e inibidores tópicos da calcineurina com boa resposta. No segundo caso, a ciclosporina foi interrompida pelo aparecimento de herpes facial exuberante e toxicidade hepática e renal no quarto dia de tratamento. No último caso, de psoríase generalizada e impétigo, medicado com flucloxacilina e gentamicina,a terapêutica foi interrompida ao sexto dia por angioedema e urticária generalizados por quadro de angioedema e urticária generalizados, interpretado como reacção de hipersensibilidade a beta-lactâmicos, não sendo contudo possível excluir papel da ciclosporina. Discussão: Os dados sobre a utilização da ciclosporina em crianças são ainda escassos. A utilização deve ser limitada a casos com indicações precisas, após considerar riscos e benefícios.

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Recent advances in psychosocial treatments for schizophrenia have targeted social cognitive deficits. A critical literature review and effect-size (ES) analysis was conducted to investigate the efficacy of comprehensive programs of social cognitive training in schizophrenia. Results revealed 16 controlled studies consisting of seven models of comprehensive treatment with only three of these treatment models investigated in more than one study. The effects of social cognitive training were reported in 11/15 studies that included facial affect recognition skills (ES=.84) and 10/13 studies that included theory-of-mind (ES=.70) as outcomes. Less than half (4/9) of studies that measured attributional style as an outcome reported effects of treatment, but effect sizes across studies were significant (ESs=.30-.52). The effect sizes for symptoms were modest, but, with the exception of positive symptoms, significant (ESs=.32-.40). The majority of trials were randomized (13/16), selected active control conditions (11/16) and included at least 30 participants (12/16). Concerns for this area of research include the absence of blinded outcome raters in more than 50% of trials and low rates of utilization of procedures for maintaining treatment fidelity. These findings provide preliminary support for the broader use of comprehensive social cognitive training procedures as a psychosocial intervention for schizophrenia.