408 research outputs found

    Utilization of Blood and Its Products

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    At present time there are a number of blood components that are more suitable for transfusion purposes than is whole blood. In order to make maximum use of blood, it is necessary that there be close cooperation between the blood bank personnel and those responsible for patient care

    Face perception: an approach to the study of autism

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    The autistic child's ability to identify others' faces and their expressions was investigated in comparison with the ability of non-autistic children. A study of the children's ability to identify peers' from isolated facial areas revealed that the autistic children were abnormally good at this task. Reasons for these findings were investigated in a series of experiments which revealed that the autistic children were also abnormally good at recognising inverted faces and inverted text. The conclusion was drawn that the autistic children's performance was due to their possessing a perceptual integration deficit which prevents them seeing stimuli like faces and words as meaningful wholes. This was investigated further by tests of their ability to discern facial expression and the results of these studies supported the above conclusion. Tests of the children's ability to lip read revealed that the autistic children also had problems with between modality perceptual integration. Studies of their ability to produce facial expressions showed them to be poor at both spontaneous and elicited expressions. Further, whilst they were as good as controls at copying facial expression, they were less able to make use of visual feedback to improve their attempts. This was seen as further evidence for a perceptual integration deficit. Finally, a computerised study of autistic children's eye movements whilst viewing live facial expressions and other stimuli supported much of the previous findings, adding the finding that they had abnormally brief visual fixation times and that they engaged in very few feature-to-feature gaze shifts. The results were discussed and found to favour a theory in which the autistic child's problems with social and communicative competence are linked to his problems with perceptual integration. The possession versus the use of abilities was discussed, as was possible sites of neurological damage, and the possibility that autistic children lack some vital usually 'innate' abilities and propensities

    Correspondence

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    An empirical comparison between stochastic and deterministic centroid initialisation for K-Means variations

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    K-Means is one of the most used algorithms for data clustering and the usual clustering method for benchmarking. Despite its wide application it is well-known that it suffers from a series of disadvantages, such as the positions of the initial clustering centres (centroids), which can greatly affect the clustering solution. Over the years many K-Means variations and initialisations techniques have been proposed with different degrees of complexity. In this study we focus on common K-Means variations and deterministic initialisation techniques and we first show that more sophisticated initialisation methods reduce or alleviates the need of complex K-Means clustering, and secondly, that deterministic methods can achieve equivalent or better performance than stochastic methods. These conclusions are obtained through extensive benchmarking using different model data sets from various studies as well as clustering data sets

    Impaired perception of facial motion in autism spectrum disorder

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    Copyright: © 2014 O’Brien et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This article has been made available through the Brunel Open Access Publishing Fund.Facial motion is a special type of biological motion that transmits cues for socio-emotional communication and enables the discrimination of properties such as gender and identity. We used animated average faces to examine the ability of adults with autism spectrum disorders (ASD) to perceive facial motion. Participants completed increasingly difficult tasks involving the discrimination of (1) sequences of facial motion, (2) the identity of individuals based on their facial motion and (3) the gender of individuals. Stimuli were presented in both upright and upside-down orientations to test for the difference in inversion effects often found when comparing ASD with controls in face perception. The ASD group’s performance was impaired relative to the control group in all three tasks and unlike the control group, the individuals with ASD failed to show an inversion effect. These results point to a deficit in facial biological motion processing in people with autism, which we suggest is linked to deficits in lower level motion processing we have previously reported

    The effect of spatial frequency and face inversion on facial expression processing in children with autism spectrum disorder

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    To investigate whether facial expression processing in children with autism spectrum disorder (ASD) is based on local information of the stimuli, we prepared low spatial frequency (LSF) images with blurred facial features and high spatial frequency (HSF) images with rich facial features from broad (normal) spatial frequency (BSF) images. Eighteen children with ASD (mean age 11.9 years) and 19 typically developing (TD) children (mean age 11.4 years) matched on nonverbal IQ were presented these stimuli in upright and inverted orientations. The children with ASD had difficulty in processing facial expressions from the BSF and LSF images, but not from the HSF images. In addition, the BSF and HSF images elicited the inversion effect in the TD children, but not in the children with ASD. In contrast, the LSF images elicited the inversion effect in both groups of children. These results suggest that children with ASD are biased towards processing facial expression based on local information, even though their capacity to process facial expressions configurally is spared

    Clinical practice: The bleeding child. Part II: Disorders of secondary hemostasis and fibrinolysis

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    Bleeding complications in children may be caused by disorders of secondary hemostasis or fibrinolysis. Characteristic features in medical history and physical examination, especially of hemophilia, are palpable deep hematomas, bleeding in joints and muscles, and recurrent bleedings. A detailed medical and family history combined with a thorough physical examination is essential to distinguish abnormal from normal bleeding and to decide whether it is necessary to perform diagnostic laboratory evaluation. Initial laboratory tests include prothrombin time and activated partial thromboplastin time. Knowledge of the classical coagulation cascade with its intrinsic, extrinsic, and common pathways, is useful to identify potential defects in the coagulation in order to decide which additional coagulation tests should be performed

    Similar exemplar pooling processes underlie the learning of facial identity and handwriting style: Evidence from typical observers and individuals with Autism

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    Considerable research has addressed whether the cognitive and neural representations recruited by faces are similar to those engaged by other types of visual stimuli. For example, research has examined the extent to which objects of expertise recruit holistic representation and engage the fusiform face area. Little is known, however, about the domain-specificity of the exemplar pooling processes thought to underlie the acquisition of familiarity with particular facial identities. In the present study we sought to compare observers’ ability to learn facial identities and handwriting styles from exposure to multiple exemplars. Crucially, while handwritten words and faces differ considerably in their topographic form, both learning tasks share a common exemplar pooling component. In our first experiment, we find that typical observers’ ability to learn facial identities and handwriting styles from exposure to multiple exemplars correlates closely. In our second experiment, we show that observers with autism spectrum disorder (ASD) are impaired at both learning tasks. Our findings suggest that similar exemplar pooling processes are recruited when learning facial identities and handwriting styles. Models of exemplar pooling originally developed to explain face learning, may therefore offer valuable insights into exemplar pooling across a range of domains, extending beyond faces. Aberrant exemplar pooling, possibly resulting from structural differences in the inferior longitudinal fasciculus, may underlie difficulties recognising familiar faces often experienced by individuals with ASD, and leave observers overly reliant on local details present in particular exemplars

    Judging the Intensity of Emotional Expression in Faces: the Effects of Colored Tints on Individuals With Autism Spectrum Disorder

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    Individuals with autism spectrum disorder (ASD) often show atypical processing of facial expressions, which may result from visual stress. In the current study, children with ASD and matched controls judged which member of a pair of faces displayed the more intense emotion. Both faces showed anger, disgust, fear, happiness, sadness or surprise but to different degrees. Faces were presented on a monitor that was tinted either gray or with a color previously selected by the participant individually as improving the clarity of text. Judgments of emotional intensity improved significantly with the addition of the preferred colored tint in the ASD group but not in controls, a result consistent with a link between visual stress and impairments in processing facial expressions in individuals with ASD. Autism Res 2016, 9: 450-459. © 2015 International Society for Autism Research, Wiley Periodicals, Inc
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