At least 13 genes control the establishment of dorsoventral polarity in the Drosophila embryo and more than 30 genes control the anteroposterior pattern of body segments. Each group of genes is thought to control pattern formation along one body axis, independently of the other group. We have used the expression of the fushi tarazu (ftz) segmentation gene as a positional marker to investigate t...

Thalamic innervation of each neocortical area is vital to cortical function, but the developmental strategies that guide axons to specific areas remain unclear. We took a new approach to determine the contribution of intracortical cues. The cortical patterning molecule fibroblast growth factor 8 (FGF8) was misexpressed in the cortical primordium to rearrange the area map. Thalamic axons faithfu...

In a recent paper of ours [Hess & Field (1993). Vision Research, 33, 2663-2670], we claim that there was a predictable relationship between position errors and contrast errors for an undersampled system. In this paper we re-state our main points. We feel that the response to that paper by Levi and Klein in the accompanying article does not require us to produce changes in our original position....

We carried out online choice experiments (CE) to investigate what value Japanese individuals assign to rare vs. familiar species in forest ecosystems, and to determine how preference heterogeneity arises. CE attributes comprised a forestry charge as the price attribute and rare vs. familiar species of animals or plants as the good to be valued. Species numbers in a 5 km mesh forest area were ev...

Human observers are able to localize the relative position of objects defined by Gaussian variations in either luminance (1st order) or contrast (2nd order). However, positional sensitivity is significantly poorer for 2nd- than for 1st-order stimuli. These judgments require the visual system to construct a representation of pertinent variation from a number of individual retinal samples-a proce...