Attenuation of perceptual asymmetries in patients with early-onset schizophrenia: Evidence in favour of reduced hemispheric differentiation in schizophrenia?

Lateral biases in visual perception have been demonstrated in normal individuals and in patients with unilateral brain lesions. It has been suggested that the absence of structural and functional asymmetries in schizophrenia could be due to a failure in lateralisation that may be most pronounced in those patients whose illness onset is at an early age. Here we examined lateral biases in patients with schizophrenia of an early onset (N = 21) and a late onset.(N = 19), and their respective age-matched control groups, using the greyscales task, a sensitive measure of asymmetries in visual processing. The stimuli consisted of two rectangles, one above the other, shaded in opposite directions and matched overall for darkness. Participants judged which of the two rectangles looked darker overall. Previous studies using this task in healthy participants have reported a reliable bias, such that the rectangle with the darker end on the left is selected preferentially. Whereas the late-onset patients in this study exhibited a perceptual bias of similar direction and magnitude to that of controls, this was not the case for the early-onset patients, who exhibited significantly less bias than their control group. The reduced perceptual bias seen in the early-onset group, but not the late-onset group, suggests an attenuation of right hemisphere mechanisms dedicated to processing vistiospatial information. The attenuated perceptual asymmetry in the early-onset group only may be consistent with the view that (i) an earlier illness onset reflects a greater loss of hemispheric differentiation and (ii) reduced functional asymmetries in the early-onset group are a manifestation of a failure to allocate functions to one or the other hemisphere.

A New Family of Distance Functions for Perceptual Similarity Retrieval of Medical Images

A long-standing challenge of content-based image retrieval (CBIR) systems is the definition of a suitable distance function to measure the similarity between images in an application context which complies with the human perception of similarity. In this paper, we present a new family of distance functions, called attribute concurrence influence distances (AID), which serve to retrieve images by similarity. These distances address an important aspect of the psychophysical notion of similarity in comparisons of images: the effect of concurrent variations in the values of different image attributes. The AID functions allow for comparisons of feature vectors by choosing one of two parameterized expressions: one targeting weak attribute concurrence influence and the other for strong concurrence influence. This paper presents the mathematical definition and implementation of the AID family for a two-dimensional feature space and its extension to any dimension. The composition of the AID family with L (p) distance family is considered to propose a procedure to determine the best distance for a specific application. Experimental results involving several sets of medical images demonstrate that, taking as reference the perception of the specialist in the field (radiologist), the AID functions perform better than the general distance functions commonly used in CBIR.

Can anticipatory skills be learned through implicit video-based perceptual training?

The aim of this experiment was to determine the effectiveness of two video-based perceptual training approaches designed to improve the anticipatory skills of junior tennis players. Players were assigned equally to an explicit learning group, an implicit learning group, a placebo group or a control group. A progressive temporal occlusion paradigm was used to examine, before and after training, the ability of the players to predict the direction of an opponent's service in an in-vivo on-court setting. The players responded either through hitting a return stroke or making a verbal prediction of stroke direction. Results revealed that the implicit learning group, whose training required them to predict serve speed direction while viewing temporally occluded video footage of the return-of-serve scenario, significantly improved their prediction accuracy after the training intervention. However, this training effect dissipated after a 32 day unfilled retention interval. The explicit learning group, who received instructions about the specific aspects of the pre-contact service kinematics that are informative with respect to service direction, did not demonstrate any significant performance improvements after the intervention. This, together with the absence of any significant improvements for the placebo and control groups, demonstrated that the improvement observed for the implicit learning group was not a consequence of either expectancy or familiarity effects.

Acoustic analysis of speech through a hearing aid: perceptual effects of changes with two-channel compression

Compression amplification significantly alters the acoustic speech signal in comparison to linear amplification. The central hypothesis of the present study was that the compression settings of a two-channel aid that best preserved the acoustic properties of speech compared to linear amplification would yield the best perceptual results, and that the compression settings that most altered the acoustic properties of speech compared to linear would yield significantly poorer speech perception. On the basis of initial acoustic analysis of the test stimuli recorded through a hearing aid, two different compression amplification settings were chosen for the perceptual study. Participants were 74 adults with mild to moderate sensorineural hearing impairment. Overall, the speech perception results supported the hypothesis. A further aim of the study was to determine if variation in participants' speech perception with compression amplification (compared to linear amplification) could be explained by the individual characteristics of age, degree of loss, dynamic range, temporal resolution, and frequency selectivity; however, no significant relationships were found.

Ocular scanning and perceptual size distortion in hemispatial neglect: effects of prism adaptation and sequential stimulus presentation

When asked to compare two lateralized shapes for horizontal size, neglect patients often indicate the left stimulus to be smaller. Gainotti and Tiacci (1971) hypothesized that this phenomenon might be related to a rightward bias in the patients' gaze. This study aimed to assess the relation between this size underestimation and oculomotor asymmetries. Eye movements were recorded while three neglect patients judged the horizontal extent of two rectangles. Two experimental manipulations were performed to increase the likelihood of symmetrical scanning of the stimulus display. The first manipulation entailed a sequential, rather than simultaneous presentation of the two rectangles. The second required adaptation to rightward displacing prisms, which is known to reduce many manifestations of neglect. All patients consistently underestimated the left rectangle, but the pattern of verbal responses and eye movements suggested different underlying causes. These include a distortion of space perception without ocular asymmetry, a failure to view the full leftward extent of the left stimulus, and a high-level response bias. Sequential presentation of the rectangles and prism adaptation reduced ocular asymmetries without affecting size underestimation. Overall, the results suggest that leftward size underestimation in neglect can arise for a number of different reasons. Incomplete leftward scanning may perhaps be sufficient to induce perceptual size distortion, but it is not a necessary prerequisite.

A normalização contabilística das microentidades: análise comparativa face à norma aplicável ás pequenas entidades

Em resultado do processo harmonizador da contabilidade ao nível da União Europeia, Portugal e os demais Estados-membros, viram necessidade de adaptar a sua normalização contabilística às Normas Internacionais de Contabilidade adotadas pela União Europeia, de forma a garantir uma maior comparabilidade da informação financeira das empresas dos diversos países. Consequentemente, foi aprovado, em Portugal, no ano 2009, o Sistema de Normalização Contabilística (SNC), que atende às diferentes necessidades de relato financeiro, incluindo um regime composto por 28 Normas Contabilísticas e de Relato Financeiro, aplicáveis à generalidade das empresas, um regime aplicável às designadas pequenas entidades, composto por uma Norma Contabilística e de Relato Financeiro para as Pequenas Entidades, e também como parte integrante do SNC, no ano 2011, foi aprovado um regime aplicável às entidades do setor não lucrativo. Todavia, e perante as características do tecido empresarial português, foi aprovado, em 2011, um regime simplificado aplicável às microentidades. Este trabalho tem por objetivo analisar este processo normalizador da contabilidade em Portugal, com especial referência à análise comparativa das normas aplicáveis às pequenas entidades e às microentidades. Com este trabalho concluímos que existem diferenças entre os dois normativos, não apenas no âmbito da dimensão e conteúdo das demonstrações financeiras, como também em termos de mensuração de alguns elementos das demonstrações financeiras, como por exemplo, dos ativos fixos tangíveis e intangíveis; destacam-se também, entre outras, diferenças ao nível de alguns conceitos, como de ativos e passivos contingentes, não mencionados no normativo das microentidades.

Contributos para a revisão da Norma ISO 9001:2008 na perspetiva de uma aproximação à realidade organizacional

Este trabalho de investigação pretende dar o seu contributo para a renovação da norma ISO 9001:2008, na perspetiva de uma maior aproximação à realidade organizacional, através da análise da perceção dos especialistas/profissionais da qualidade. Numa primeira fase foi realizada uma abordagem ao estado da arte, relativamente ao conceito qualidade, à organização International Organization for Standardization (ISO), ao processo de alteração da norma, ao referencial normativo ISO 9001:2008, ao comportamento ao nível mundial da certificação segundo a norma ISO 9001:2008 e finalmente ao processo de preparação da revisão da norma ISO 9001:2008 a ser divulgada em 2015, cuja publicação na versão final, está prevista para novembro de 2015. Com a finalidade de apurar as opiniões/sugestões dos especialistas da área realizou-se um questionário que foi colocado online nas principais redes sociais e também enviado para alguns auditores, consultores, gestores/técnicos da qualidade e gestores de topo. Participaram 60 profissionais. Após da recolha dos dados, estes foram tratados através da utilização do software statistical package for the social sciences (SPSS). Os resultados obtidos demonstraram que a perceção dos profissionais vai de encontro às alterações que já estão propostas para a nova norma ISO 9001:2015. Das alterações sugeridas é de realçar, uma maior adequação da norma às diversas áreas de negócio, maior exigência nos aspetos ligados às organizações, adequação de conceitos e objetivos, compatibilidade com outros referenciais, complementar áreas como segurança, finanças e/ou responsabilidade social e maior envolvimento das organizações no processo de renovação da norma. No que concerne às expetativas, os profissionais esperam que a nova norma ISO 9001:2015 venha facilitar a integração e compreensão dos vários sistemas, maior adequação e credibilização junto das organizações e uma melhoria generalizada. Desta forma com o presente trabalho, espera-se ter contribuído para a clarificação das dificuldades sentidas na adequação do atual referencial à realidade organizacional. Assim como dar um contributo para futura apresentação aos responsáveis pelo acompanhamento da atividade normativa em Portugal (comité técnico CT80).