Faithful representation of similarities among three-dimensional shapes in human vision.

Efficient and reliable classification of visual stimuli requires that their representations reside a low-dimensional and, therefore, computationally manageable feature space. We investigated the ability of the human visual system to derive such representations from the sensory input-a highly nontrivial task, given the million or so dimensions of the visual signal at its entry point to the cortex. In a series of experiments, subjects were presented with sets of parametrically defined shapes; the points in the common high-dimensional parameter space corresponding to the individual shapes formed regular planar (two-dimensional) patterns such as a triangle, a square, etc. We then used multidimensional scaling to arrange the shapes in planar configurations, dictated by their experimentally determined perceived similarities. The resulting configurations closely resembled the original arrangements of the stimuli in the parameter space. This achievement of the human visual system was replicated by a computational model derived from a theory of object representation in the brain, according to which similarities between objects, and not the geometry of each object, need to be faithfully represented.

(Table 1, page 661) Average composition of fossil nodules from three localities studied in the Transdanubian Central Mountains of Hungary

Fossil manganese nodules and encrustations from seamount' and basin' localities in the Transdanubian Central Mountains of Hungary are lithologically, mineralogically and chemically similar to some modern marine ferromanganese oxide deposits, and show no evidence of postdepositional changes other than cementation. Five groups of deposits were encountered: Fe/Mn nodules, encrusted shells, pavements, stains, and Fe oxide encrusted intraclasts, the first three of which are specific to the 'seamount' environment and the last to the basins'. Optical and electron microprobe investigation of the samples shows them to exhibit many similarities with modern ferromanganese oxide deposits, and that many of the nodules are surrounded by a halo of dispersed ferromanganese oxides, strongly suggesting that they continued to accrete metals through the pore waters of unlithified sediments for a period after burial. By contrast, pavements which appear to have grown on hardgrounds at the sea floor show little or no evidence of derivation of metals from underlying sediments. Geochemical investigations on the deposits show the seamount' varieties to be closer in composition to most modern nodules and crusts than the basin' varieties, and that the latter are essentially manganese and trace-element-poor ferruginous deposits. Nevertheless, all can be more or less compositionally equated with modern ferromanganese oxide deposits forming in marginal Atlantic environments, which would be in accord with the proposed depositional environment of the Transdanubian Central Mountains based on other evidence.

Captains of the three student companies in 1861

Handwritten on verso: civil war volunteer. Printed sticker on verso: W. Nessler

The economics of reducing the county road system: three case studies in Iowa. Final report.

Transportation Department, Office of University Research, Washington, D.C.

The recreation benefits of water quality improvements : analysis of day trips in urban setting /

Mode of access: Internet.

Livestock health encyclopedia; the control of diseases and parasites in cattle, sheep and goats, swine, horses and mules. /

Bibliography: p. 605-613.

The Statutes of New Zealand : passed in the ... year of the reign of ... and the ... session of the ... Parliament of New Zealand begun and holden at Auckland on the ... day of ... in the year of Our Lord .

Vols. for <1870>- published in Wellington by the government printer.

Three particle effects in the pair distribution function for He [superscript 4] gas,

"Supported in part by the Atomic Energy Commission."