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Biomedical subjects

J Sprey

Publications and source records attributed to J Sprey.

4 recordsLinked to original sources
PubMed1994

Relocation accuracy on HOME computerized microscopes.

A major practical advantage of the HOME (highly optimized microscope environment) computerized microscope is the facility for relocating cells or other microscopic objects. Features can be marked directly on the microscope image using a mouse-driven cursor, and an interactive finder can then be used to relocate the marked features. Tests on a prototype HOME microscope have shown that positions can be relocated with an accuracy of standard deviation (SD) < 7 microm. The marked features could also be relocated on a second HOME microscope, although with somewhat reduced accuracy (standard deviations of < 17 microm). The system provides a very user-friendly environment for tasks requiring relocation of microscopic objects.

Calibration↗
PubMed1992

Adaptive classifiers for dicentric chromosomes.

Classification of dicentric chromosomes in a practical automatic screening system comprises three stages. The first generates plausible centromere candidates from each chromosome in an automatically segmented metaphase, and uses contextual knowledge to generate distributions of "probably true" and "probably false" centromeres, thus adapting to the conditions within a particular metaphase. The second stage classifier uses these distributions to re-classify the candidates as centromeres or non-centromeres. From this classification, likely dicentrics are found by counting centromeres; a third classifier attempts to reject false positives among the likely dicentric chromosomes, by comparing the feature values of the proposed centromeres of a chromosome and rejecting chromosomes for which these values do not satisfy certain similarity criteria. The second stage classifier may be a simple box classifier, or may use a variety of parametric Bayesian methods. The performance of these alternatives has been tested both on reference data sets comprising about 600 metaphases, and on larger data sets when embedded in a practical fully automatic dicentric pre-screening system. When operating parameters were such that a similar number of true positives were found by both classifiers, the Bayesian classifier produced about half as many false positive errors as the box classifier, with the final false positive rate being in the region of one candidate dicentric chromosome in every four cells.

Chromosome Aberrations↗
PubMed1985

Adolescents' relationships with grandparents: an empirical contribution to conceptual clarification.

Findings from research in which a sample of 132 late adolescents completed questionnaires about their relationships with each of their living grandparents are reported. The grandchildren were most likely to describe their relationships with their maternal grandmothers as close and least likely to describe their bonds with the paternal grandparents in this way. Grandchildren's current evaluations of relationships with their grandparents were affected by access to the particular grandparent in childhood and their perceptions of each of their parents' relationships with the specific grandparent. The findings demonstrate empirically the importance for future research of conceptualizing the grandparent-grandchild tie as both particularistic and mediated through a biological and an in-law-child.

Adolescent↗