Showing 1661 - 1670 of 2039 Items
Leonard Baskin's Speech of Acceptance on Receiving the Medal of the American Institute of Graphic Arts, New York, April 28, 1965
Date: 1965-01-01
Creator: Leonard Baskin
Access: Open access
- "This speech has been made into a booklet for the Bowdoin College Museum of Art, for the "Typophiles" (monograph no. 78) and for the friends of Leonard Baskin and the Spiral Press ..."Colophon
Waterborne cues from crabs induce thicker skeletons, smaller gonads and size-specific changes in growth rate in sea urchins
Date: 2009-04-01
Creator: Rebecca Selden
Amy S. Johnson
Olaf Ellers
Access: Open access
- Indirect predator-induced effects on growth, morphology and reproduction have been extensively studied in marine invertebrates but usually without consideration of size-specific effects and not at all in post-metamorphic echinoids. Urchins are an unusually good system, in which, to study size effects because individuals of various ages within one species span four orders of magnitude in weight while retaining a nearly isometric morphology. We tracked growth of urchins, Strongylocentrotus droebachiensis (0.013-161.385 g), in the presence or absence of waterborne cues from predatory Jonah crabs, Cancer borealis. We ran experiments at ambient temperatures, once for 4 weeks during summer and again, with a second set of urchins, for 22 weeks over winter. We used a scaled, cube-root transformation of weight for measuring size more precisely and for equalizing variance across sizes. Growth rate of the smallest urchins (summer: diameter; winter: diameter) decreased by 40-42% in response to crab cues. In contrast, growth rate of larger urchins was unaffected in the summer and increased in response to crab scent by 7% in the winter. At the end of the 22-week experiment, additional gonadal and skeletal variables were measured. Cue-exposed urchins developed heavier, thicker skeletons and smaller gonads, but no differences in spine length or jaw size. The differences depended on urchin size, suggesting that there are size-specific shifts in gonadal and somatic investment in urchins.
Peatlands as a model ecosystem of soil carbon dynamics: Reply to Comment on "peatlands and their role in the global carbon cycle"
Date: 2012-01-01
Creator: Zicheng Yu
D. W. Beilman
S. Frolking
G. M. MacDonald
N. T., Roulet
P. Camill
D. J. Charman
Access: Open access
SU(N) group-theory constraints on color-ordered five-point amplitudes at all loop orders
Date: 2012-05-21
Creator: Alexander C. Edison
Stephen G. Naculich
Access: Open access
- Color-ordered amplitudes for the scattering of n particles in the adjoint representation of SU(N) gauge theory satisfy constraints arising solely from group theory. We derive these constraints for n=.5 at all loop orders using an iterative approach. These constraints generalize well-known tree-level and one-loop group theory relations. © 2012 Elsevier B.V.