25 research outputs found
Surgery for complications of trans-catheter closure of atrial septal defects: a multi-institutional study from the European Congenital Heart Surgeons Association
Objective: This study aims to analyse the collective experience of participating European Congenital Heart Surgeons Association centres in the surgical management of complications resulting from trans-catheter closure of atrial septal defects (ASDs). Methods: The records of all (n=56) patients, aged 3-70 years (median 18 years), who underwent surgery for complications of trans-catheter ASD closure in 19 participating institutions over a 10-year period (1997-2007) were retrospectively reviewed. Risk factors for surgical complications were sought. Surgical outcomes were compared with those reported for primary surgical ASD closure in the European Association of Cardio-thoracic Surgery Congenital Database. Results: A wide range of ASD sizes (5-34mm) and devices of various types and sizes (range 12-60mm) were involved, including 13 devices less than 20mm. Complications leading to surgery included embolisation (n=29), thrombosis/thrombo-embolism/cerebral ischaemia or stroke (n=12), significant residual shunt (n=12), aortic or atrial perforation or erosion (n=9), haemopericardium with tamponade (n=5), aortic or mitral valve injury (n=2) and endocarditis (n=1). Surgery (39 early emergent and 17 late operations) involved device removal, repair of damaged structures and ASD closure. Late operations were needed 12 days to 8 years (median 3 years) after device implantation. There were three hospital deaths (mortality 5.4%). During the same time period, mortality for all 4453 surgical ASD closures reported in the European Association of Cardio-Thoracic Surgery Congenital Database was 0.36% (p=0.001). Conclusions: Trans-catheter device closure of ASDs, even in cases when small devices are used, can lead to significant complications requiring surgical intervention. Once a complication leading to surgery occurs, mortality is significantly greater than that of primary surgical ASD closure. Major complications can occur late after device placement. Therefore, lifelong follow-up of patients in whom ASDs have been closed by devices is mandator
Max Wertheimer productive thinking
Max Wertheimer (1880-1943), a pioneer of 20th-century psychology, had a major influence on the development of cognitive psychology, especially the psychology of perception and of productive thinking. His work “Productive Thinking” (1945), written in New York, is regarded as a milestone in creativity research. Consisting of many examples of creative thought processes - from geometric tasks to socio-psychologically relevant conflict resolutions to the development of Einstein’s theory of relativity - the book leads the reader through a multi-faceted body of thought in the psychology of thinking. Detailed historical commentary by Viktor Sarris. Only a few texts in psychology have remained significant even after a period of three quarters of a century - Max Wertheimer’s Productive Thinking is such an exception. This book, which also presents an exposition of Gestalt psychology, highlights the “productive” (insightful) versus automatic (unreflected) thought processes for many areas of life. In addition to examples from school teaching, the chapter on the emergence of Albert Einstein's theory of relativity is of lasting interest to today's generation of psychologists, pedagogues, brain researchers, neuroinformatics scientists/researchers and philosophers. Wertheimer had the unique opportunity to analyze Einstein’s thinking in direct conversation. An introductory commentary by Viktor Sarris for this new edition of the first publication of Productive Thinking in 1945 offers a detailed account of the genesis and reception of Wertheimer’s work
Memory and assimilation to context in delayed matching-to-sample
This paper reports effects of short-term memory and context stimuli on recognition of visual stimuli. After presentation of a square as the target stimulus, participants had to store the target during a variable delay, until they had to identify the target within a sample of seven squares that differed systematically in size (context variation). Marked context effects (“shifts”) that occurred as responses to the test series were obtained when sets of comparison stimuli were arranged asymmetrically with respect to targets. Participants overestimated the size of the target in a set of larger comparison stimuli by choosing a larger stimulus to match the target, and vice versa (Experiment 1). This assimilation effect increased with longer delays between target offset and the onset of comparison stimuli (Experiment 2). Briefer target exposure also induced stronger assimilation (Experiment 3). The results indicated that visual short-term memory modulates (contextual) stimulus integration in delayed matching to sample. A working model of memory and contextual effects in matching is discussed
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Psychophysical Context Effects in Chickens Gallus Gallus Domesticus ( Hubbards )
A quantitative frame-of-reference ( FR ) model that has been successfully tested in humans was examined in generalization experiments with chickens. In Experiment 1, three groups of two chickens each were trained to discriminate between cubes different in volume and tested with a series of cubes with volumes either below, surrounding, or above the training stimuli. The obtained psychometric functions support the assumption that asymmetrical testing after two stimulus-two response training leads to the changes predicted by the FR model. In Experiment 2 shifts in the context defining the test series were administered by gradually enlarging the distance between training and test stimuli. While context effects were found in both experiments these were more pronounced in Experiment 2. The results support the general hypothesis that perception in animals undergoes context effects similar to those obtained in human subjects
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Comparative Psychophysics: Some Contextual Effects in Birds and Humans
Three different types of psychophysical context effects have been studied in comparative experiments with animals and humans. The main context variables investigated were: (1) range of the test series; (2) asymmetry of training to test stimuli (anchor effects); and (3) frequency distribution of the test stimuli. A two-stimulus, two response training procedure, followed by various generalization tests, was used. All subjects (19 chickens and 128 humans) were trained and tested with cubes of different sizes. The psychometric functions support the general assumption that perception in birds undergoes psychophysical context effects similar to that observed in humans. However, while all three variables affected the judgments of human subjects, the choices of chickens and human infants were not strongly affected by the frequency distribution of the test stimuli. These data suggest that two factors are responsible for the three contextual effects investigated: a basic perceptual factor invariant across species and age groups and a cognitive component