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Biomedical subjects

Robert J Peters

Publications and source records attributed to Robert J Peters.

3 recordsLinked to original sources

Human visual object categorization can be described by models with low memory capacity.

Studies of high-level models of visual object categorization have left unresolved issues of neurobiological relevance, including how features are extracted from the image and the role played by memory capacity in categorization performance. We compared the ability of a comprehensive set of models to match the categorization performance of human observers while explicitly accounting for the models' numbers of free parameters. The most successful models did not require a large memory capacity, suggesting that a sparse, abstracted representation of category properties may underlie categorization performance. This type of representation--different from classical prototype abstraction--could also be extracted directly from two-dimensional images via a biologically plausible early-vision model, rather than relying on experimenter-imposed features.

Adolescent↗

Nearpoint of convergence: test procedure, target selection, and normative data.

BACKGROUND: The purpose of this study was to help determine the most appropriate target to be used for the assessment of the nearpoint of convergence, normative data for the break and recovery in adults, and the diagnostic value of the red-glass modification and repetition of the nearpoint of convergence. METHODS: A total of 175 subjects with normal binocular vision and 38 subjects with convergence insufficiency were evaluated. The nearpoint of convergence was measured three ways, with an accommodative target, a penlight, and a penlight with red and green glasses. The nearpoint of convergence was also measured using a penlight for 10 repetitions. RESULTS: Results suggest a clinical cutoff value of 5 cm for the nearpoint of convergence break and 7 cm for the nearpoint of convergence recovery with either an accommodative target or a penlight with red and green glasses. CONCLUSION: This study establishes normative data for the nearpoint of convergence break and recovery in the adult population and supports the value of various test modifications when other testing is equivocal.

Accommodation, Ocular↗

Navy Dental Corps: ninety years ... and forward.

The Navy Dental Corps is responsible for ensuring the readiness of America's sailors and marines and optimizing their oral health. This article traces the history from the 1912 Act of Congress authorizing thirty "assistant dental surgeons" as the first Navy Dental Corps through service around the world. Navy dentists have seen service in every war and action in the past ninety years, reaching a peak of seven thousand officers and eleven thousand technicians in World War II. The Navy Dental Corps has served in the Korean and Vietnam Wars, Beirut, Somalia, Haiti, 9/11, Desert Storm, Desert Shield, and Operation Iraqi Freedom.

History, 19th Century↗