We study the bilipschitz equivalence type of tree-graded spaces, showing that asymptotic cones of relatively hyperbolic groups (resp. asymptotic cones of groups containing a cut-point) only depend on the bilipschitz equivalence types of the pieces in the standard (resp. minimal) tree-graded structure. In particular, the asymptotic cones of many relatively hyperbolic groups do not depend on the ...

We describe a detailed analysis of the spatial arrangement of L, M and S cones in the living eyes of two humans and one monkey. We analyze the cone mosaics near 1 degrees eccentricity using statistical methods that characterize the arrangement of each type of cone in the mosaic of photoreceptors. In all eyes, the M and L cones are arranged randomly. This gives rise to patches containing cones o...

Spatial and temporal variability in cone production may influence post-disturbance succession, yet it is not well understood. We sampled 15year old lodgepole pine (Pinus contorta var. latifolia) stands (n = 16) that regenerated naturally after the 1988 Yellowstone fires and varied in stand density (566–545,200 stems ha ) and elevation to quantify and explain variation in cone production. Among ...

The fluorescent lipophilic dye 3,3'-dihexyloxacarbocyanine iodide [DiOC6(3)] was used to examine the distribution of membrane-bound organelles in growth cones of cultured rat sympathetic neurons. Within chemically fixed growth cones, intense DiOC6(3) fluorescence was localized predominately to the base or central region of growth cones. However, in most growth cones several thin DiOC6(3)-fluore...

The role of specific axonal tracts for the guidance of growth cones was investigated by examining axonal outgrowth within the abnormal brain tracts of zebrafish cyclops mutants. Normally, the earliest differentiating neurons in the zebrafish brain establish a simple scaffold of axonal tracts. Later-developing axons follow cell-specific pathways within this axonal scaffold. In cyclops embryos, t...

During nervous system development, neurons form synaptic contacts with distant target cells. These connections are formed by the extension of axonal processes along predetermined pathways. Axon outgrowth is directed by growth cones located at the tips of these neuronal processes. Although the behavior of growth cones has been well-characterized in vitro, it is difficult to observe growth cones ...

Efficient points are obtained for cone-ordered maximizations in n R using the method of scalarization. Various scalarizations are presented for ordering cones in general and then for the important special case of polyhedral cones. For polyhedral cones, it is shown how to find vectors in the positive dual cone that are needed for a scalarized objective function. Instructive examples are presented.

A systematic electron microscopic study was made of the structure of foveal cones of Macaca spp. Transverse sections of inner (IS) and outer segments (OS) were made in sequence, from the pigment epithelial zone (PEZ) to the outer limiting membrane (OLM). The smallest diameters of hundreds of cone sections were measured from electron micrographs with a Zeiss particle-size analyzer, and analyzed ...

The organization of the renal medulla of the Gambel's quail, Callipepla gambelii, kidney was examined to determine the number of loops of Henle and collecting ducts and the surface area occupied by the different nephron segments as a function of distance down the medullary cones. Eleven medullary cones were dissected from the kidneys of four birds, and the tissue was processed and sectioned for...

The interactions between many species are structured in a geographic mosaic of populations among which selection is divergent. Here we tested the hypothesis that such a geographic selection mosaic arises for common crossbills (Loxia curvirostra) feeding on seeds in the cones of Aleppo pine (Pinus halepensis) because of geographic variation in the occurrence of European red squirrels (Sciurus vu...