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Biomedical subjects

S Bíró

Publications and source records attributed to S Bíró.

6 recordsLinked to original sources
PubMed2001

The execution of arbitrary procedures by children with autism.

Executive tasks typically contain a prepotent lure. In addition, they require individuals either to (a) follow arbitrary procedures or (b) update their model of the physical world. Recent research suggests that children with autism may be challenged only by executive tasks of the former kind (containing arbitrary rules). We asked whether this continues to be true when there is no prepotent lure, comparing performance on (a) a task with arbitrariness but without prepotency with (b) a task with both features and (c) a task with neither. The participants with autism performed at a lower level than comparison groups on the first and second task but not on the third task. This outcome is consistent with the view that autism is associated with difficulties in following arbitrary procedures per se. We try to locate difficulties with acting on the basis arbitrary rules in relation to more mainstream ideas about autistic executive dysfunction.

Adolescent↗
PubMed1999

Goal attribution without agency cues: the perception of 'pure reason' in infancy.

The proper domain of naive psychological reasoning is human action and human mental states but such reasoning is frequently applied to non-human phenomena as well. The studies reported in this paper test the validity of the currently widespread belief that this tendency is rooted in the fact that naive psychological reasoning is initially restricted to, and triggered by, the perception of self-initiated movement of agents. We report three habituation experiments which examine the necessary conditions under which infants invoke a psychological principle, namely the principle of rational action, to interpret behaviour as goal directed action. Experiment 1 revealed that the principle of rational action already operates at 9 (but not yet at 6) months of age. Experiment 2 demonstrated that perceptual cues indicating agency, such as self-propulsion, are not necessary prerequisites for interpreting behaviour in terms of the principle of rational action. Experiment 3 confirmed that this effect cannot be attributed to generalisation of agentive properties from one object to another. These results suggest that the domain of naive psychology is initially defined only by the applicability of its core principles and its ontology is not restricted to (featurally identified) object kinds such as persons, animates, or agents. We argue that in its initial state naive psychological reasoning is not a cue-based but a principle-based theory.

Age Factors↗
PubMed1999

Identification of factor C protein from Streptomyces griseus by microelectrospray mass spectrometry.

Factor C, an extracellular signal protein of cellular differentiation, was studied and significant homology was found to several zinc finger-type regulatory proteins. The complete amino acid sequence, deduced from the gene, that encodes the protein, did not support the hypothesis that this protein might be a zinc finger-type regulatory protein. However, a theoretical single nucleotide insertion in the gene can result in another similarly sized protein containing about 20 His residues, which would be responsible for the high zinc affinity of factor C. The protein sample was reduced, alkylated and then in-gel digested with trypsin. The peptide fragments were then separated by capillary chromatography and identified by microelectrospray mass spectrometry. Peaks of higher intensity were sequenced by tandem mass spectrometry. The identified peptide fragments and the measured molecular mass of factor C protein also confirmed the original sequence of protein, as there was no shift in the open reading frame.

Amino Acid Sequence↗
PubMed1997

Phenotypic heterogeneity of the progeny of Streptomyces griseus conidia.

In order to understand the complex ontogenetical processes, the development of Streptomyces (S.) griseus was applied as a model. The developmental cycle of S. griseus starts and ends as a conidium. In between, coenocytic mycelium develops which, if studied by cytomorphological or biochemical methods, exhibits conspicious heterogeneity. The hyphae develop into young, transient and old vegetative hyphae and different stages of reproductive forms. In developmentally blocked mutants these sequences of events appear mixed in all possible associations. It seems as if the program of development could be divided into several subprograms. The quantitative evaluation of the results show that the individual morphological markers exhibit certain independence from each other realized with a given probability. The conidia of S. griseus are also heterogeneous concerning all morphological and physiological traits examined so far (shape, size, light refraction, staining and shape of nucleoids with Feulgen, methyl green--pyronine, intensity and form of polysaccharide distribution, heat resistance, etc.). Kinetics of the survival curves of two S. griseus strains--a well-sporulating and its developmentally blocked mutant /24/--are different from each other, one has many more heat resistant conidia than the other but the kinetics of the survival curves of the two S. griseus strains indicate that spore populations of both react differently to heat treatment and heat resistance can be modeled by assuming the presence of two independent subpopulations of spores with different heat sensitivity. The emergence of two distinct subpopulations with (possibly) the same genetic make-up is designated: phenotypic segregation. Heat resistance is first of all species specific (genetically determined) but the epigenetic segregation seems to be characteristic of the developmental process. This process can in certain mutants be affected by environmental conditions and more importantly by the so-called autoregulators (A-factor and factor C). Factor C and A-factor are needed to normal development, if their quantity or the time of addition to the culture was not optimal, the quantity of spores decreased.

4-Butyrolactone↗
PubMed1995

Taking the intentional stance at 12 months of age.

This paper reports a habituation study indicating that 12-month-old infants can take the "intentional stance" in interpreting the goal-directed spatial behavior of a rational agent. First, we examine previous empirical claims suggesting that the ability to attribute intentions to others emerges during the second half of the first year. It is argued that neither the perceptual evidence (concerning the early ability to discriminate agents), nor the behavioral data (indicating the use of communicative gestures for instrumental purposes) are sufficient to support such claims about the early appearance of a theory of mind, as there are alternative explanations for these phenomena in terms of simpler psychological processes. It is then suggested that to show that an infant indeed attributes an intention to interpret the goal-directed behavior of a rational agent, one needs to demonstrate that the baby can generate an expectation about the most rational future means action that the agent will perform in a new situation to achieve its goal. We then describe a visual habituation study that meets this requirement. The results demonstrate that based on the equifinal structure of an agent's spatial behavior, 12-month-old infants can identify the agent's goal and interpret its actions causally in relation to it. Furthermore, our study indicates that infants of this age are able to evaluate the rationality of the agent's goal-directed actions, which is a necessary requirement for applying the intentional stance. In closing, we discuss some of the theoretical and methodological implications of our study.

Analysis of Variance↗