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Biomedical subjects

F Bonadonna

Publications and source records attributed to F Bonadonna.

8 recordsLinked to original sources
PubMed1998

Homing pigeons use olfactory cues for navigation in england

Although the use of olfactory cues in pigeon navigation is well established, the generality of olfactory navigation remains uncertain because of apparent variability in results gained by different researchers in different regions. We report the results of the first experiments investigating the effect of anosmia on homing pigeons reared in a previously uninvestigated region, southern England. In series 1, experienced birds showed little effect of anosmia induced with zinc sulphate at unfamiliar sites 30 km and 39 km from the loft, but treated birds were significantly poorer than controls at homing from an unfamiliar site 66 km distant (and in pooled results). In series 2, naive (untrained) birds, both control and zinc-sulphate-treated, showed poor homing abilities and initial orientation from sites 25 km, 36 km and 39 km from the loft. Nevertheless, in pooled results, controls showed significantly better homeward orientation than anosmic birds and were significantly more likely to home on the day of release. The most likely explanation for our results is that pigeons are able to use olfactory navigation in southern England, but that for some reason the olfactory map is relatively weak.

Journal Article↗
PubMed1996

Behavioural effects of ablations of the presumed 'prefrontal cortex' or the corticoid in pigeons.

This study further explored functional similarities of mammalian prefrontal cortex and its presumed equivalent in pigeons. Our results show that the performance of delayed alternation of pigeons in an Y-maze is impaired following ablations of the prefrontal equivalent together with the corticoid but not of the corticoid alone. In the same maze, discrimination between vertical and horizontal stripes was unimpaired regardless of the lesion. Our results added the following new information. (1) Corticoid is not essentially involved in mediation of delayed responding. (2) Like monkeys, pigeons take much fewer trials to learn delayed alternation in a maze than in an operant chamber. (3) Lesions of the pigeon equivalent of the prefrontal cortex impair delayed responding also in the new apparatus. (4) These lesions do not impair visual pattern discrimination. Our results do not contradict the hypothesis that the postero-dorso-lateral neostriatum in pigeons is comparable to the prefrontal cortex in mammals.

Animals↗
PubMed1995

The homing behaviour of Cory's shearwaters (Calonectris diomedea) studied by means of a direction recorder

A direction recorder, which can be carried by a flying bird on its back, has been used for the first time on a wild species. The device can detect and record the direction in which a bird is heading during flight. Cory's shearwaters (Calonectris diomedea) were moved from their nesting colony to five different sites and fitted with direction recorders, and four homing flight paths were obtained. Our data show that the displaced birds were able to assume and maintain a homeward course soon after release over large areas of open sea, completely devoid of guiding features; topographical elements are, therefore, not necessary for correct orientation.

Journal Article↗
PubMed1986

[Quantitative evaluation of the phase image in radionuclide ventriculography ].

A functional image is a representation that enhances a particular characteristic of organ behaviour (feature enhancement) with a concomitant reduction or elimination of other informations. The functional image of phase (PI), obtained by Fourier analysis, may be interpreted to represent the onset of counts reduction or contraction in each region of the heart. Phase Spreading (PS), is a parameter derived from PI and represents ventricular temporal behaviour including some spatial information. Phase analysis and PS are very sensitive tools in the diagnosis and characterization of cardiac pathology. PS is a specific indicator of CAD, allows the introduction of normal ranges and is an example of quantitative evaluation of functional images.

Coronary Disease↗
PubMedDate not supplied

Artificial intelligence techniques for cancer treatment planning.

An artificial intelligence system, NEWCHEM, for the development of new oncology therapies is described. This system takes into account the most recent advances in molecular and cellular biology and in cell-drug interaction, and aims to guide experimentation in the design of new optimal protocols. Further work is being carried out, aimed to embody in the system all the basic knowledge of biology, physiopathology and pharmacology, to reason qualitatively from first principles so as to be able to suggest cancer therapies.

Animals↗
PubMedDate not supplied

HyperShell: an expert system shell in a hypermedia environment--application in medical audiology.

HyperShell is an expert system shell developed in a hypermedia environment. Several artificial intelligence techniques such as frames and semantic networks are used in an original interpretation to enhance the interaction between the user and the program. The typical navigation tools of hypermedia such as clickable buttons and text search are extended to the semantic structure of HyperShell, creating a set of new tools. Examples from a medical expert system (Audex HM) developed in HyperShell are described.

Audiology↗
PubMedDate not supplied

Visual knowledge processing in computer-assisted radiology: a consultation system.

This paper presents Visual Heuristics, a consultation system for diagnosis based on thorax radiograph recording. Visual Heuristics uses both prototypical representations of physiological and pathological states and reasoning aimed to infer conclusions from pathological or physiological conditions, establishing correspondences between pathological or physiological states and semantic descriptions of images. Images are assembled with groups of descriptors that guide the recognition process, achieving the possibility of comparisons with real images on the basis of 'expected' images. The system may be employed to generate a dynamic atlas that does not contain proper images, but generates them.

Artificial Intelligence↗