Object recognition in primates is mediated by the ventral visual pathway and is classically described as a feedforward hierarchy of increasingly sophisticated representations. Neurons in macaque monkey area V4, an intermediate stage along the ventral pathway, have been shown to exhibit selectivity to complex boundary conformation and invariance to spatial translation. How could such a represent...

A minimal model is exactly solved for electron spin transport on a helix. Electron transport is assumed to be supported by well oriented p(z) type orbitals on base molecules forming a staircase of definite chirality. In a tight binding interpretation, the spin-orbit coupling (SOC) opens up an effective π(z) - π(z) coupling via interbase p(x,y) - p(z) hopping, introducing spin coupled transport....

Using a combination of anion photoelectron spectroscopy and density functional theory calculations, we explored the influence of the shell model on H atom site selectivity in Al(13)H(-). Photoelectron spectra revealed that Al(13)H(-) has two anionic isomers and for both of them provided vertical detachment energies (VDEs). Theoretical calculations found that the structures of these anionic isom...

We demonstrate a cortical circuit based on known anatomical details and cellular properties which achieves sharp orientation tuning despite poorly tuned thalamo-cortical input. Sharp tuning arises emergently from excitatory interactions between similarly tuned neurons, which also receive broadly tuned inhibition. This model accounts for data obtained from intracellular recording and pharmacolog...

in a novel dual bed reactor fischer-tropsch synthesis was studied by using two diffrent cobalt catalysts. an alkali-promoted cobalt catalyst was used in the first bed of a fixed-bed reactor followed by a rutenuim promoted cobalt catalyst in the second bed. the activity, product selectivity and accelerated deactivation of the system were assessed and compared with a conventional single bed react...

an extensive study of fischer-tropsch synthesis (fts) on alumina-supported cobalt catalysts with different amounts of cobalt is reported. up to 40 wt % of cobalt, is added to the catalysts by impregnation method. the effect of the cobalt loading on the reducibility of the cobalt oxide species, dispersion of the cobalt, average clusters size, water-gas shift (wgs) activity and activity and selec...

We report the results of psychophysical experiments on color contrast induction. In earlier work [Vision Res. 34, 3111 (1994)], we showed that modulating the spatial contrast of an annulus in time induces an apparent modulation of the contrast of a central disk, at isoluminance. Here we vary the chromatic properties of disk and annulus systematically in a study of the interactions among the lum...

Neurons in the primate extrastriate cortex are highly selective for complex stimulus features such as faces, objects, and motion patterns. One explanation for this selectivity is that neurons in these areas carry out sophisticated computations on the outputs of lower-level areas such as primary visual cortex (V1), where neuronal selectivity is often modeled in terms of linear spatiotemporal fil...

In this paper we present a class of algorithms for similarity learningon spaces of images. The general framework that we introduce is mo-tivated by some well-known hierarchical pre-processing architectures forobject recognition which have been developed during the last decade, andwhich have been in some cases inspired by functional models of the ven-tral stream of the vi...