Search Results - (Author, Cooperation:J. T. Stevens)

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  1. 1
    S. A. Sievers ; J. Karanicolas ; H. W. Chang ; A. Zhao ; L. Jiang ; O. Zirafi ; J. T. Stevens ; J. Munch ; D. Baker ; D. Eisenberg
    Nature Publishing Group (NPG)
    Published 2011
    Staff View
    Publication Date:
    2011-06-17
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Amino Acid Sequence ; Amino Acids/*chemistry/*pharmacology ; Amyloid/*antagonists & inhibitors/*chemistry/metabolism ; Amyloid beta-Peptides/antagonists & inhibitors/chemistry/metabolism ; Computer-Aided Design ; *Drug Design ; HIV Infections/virology ; Hydrogen Bonding ; Kinetics ; Models, Molecular ; Peptides/*chemistry/*pharmacology ; Polylysine/pharmacology ; Protein Conformation ; tau Proteins/antagonists & inhibitors
    Published by:
    http://www.nature.com/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    T. Nagano ; Y. Lubling ; T. J. Stevens ; S. Schoenfelder ; E. Yaffe ; W. Dean ; E. D. Laue ; A. Tanay ; P. Fraser
    Nature Publishing Group (NPG)
    Published 2013
    Staff View
    Publication Date:
    2013-09-27
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Animals ; Cell Nucleus/genetics ; Chromatin/chemistry ; Chromosomes/*chemistry/genetics ; *Genetic Techniques ; Male ; Mice ; *Models, Molecular ; Molecular Conformation ; Single-Cell Analysis ; X Chromosome/chemistry/genetics
    Published by:
    http://www.nature.com/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Stevens, J. T. ; Greene, F. E.
    Springer
    Published 1974
    Staff View
    ISSN:
    1432-0800
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Energy, Environment Protection, Nuclear Power Engineering
    Medicine
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01685011

    Articles: DFG German National Licenses
  4. 4
    Staff View
    ISSN:
    1432-1939
    Keywords:
    Pollination ; Archilochus colubris ; Monarda ; Feeding ; Nectar guides
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Notes:
    Abstract Nectar guides are common among insect-pollinated plants, yet are thought to be rare or absent among hummingbird-pollinated plants. We hypothesize that the lower lips and trumpet-shaped orifices of many hummingbird flowers act as nectar guides to direct hummingbirds to the flowers' nectar and orient the birds for pollination. To test this hypothesis we conducted laboratory experiments using flowers of Monarda didyma (bee balm) and M. fistulosa (wild bergamot), which have orifice widths of about 4 mm and 2 mm, respectively, and latex flowers with orifice widths of 4 mm and 2 mm and three orifice shapes (trumpet, lipped, and lipless). Rubythroated hummingbirds (Archilochus colubris) made fewer errors during bill insertion and spent a smaller proportion of their feeding visit in error at M. didyma flowers than at M. fistulosa flowers, and at unaltered flowers of both species than at flowers with lower lips removed. Handling times were longer at both lipped and lipless flowers of M. didyma than at those of M. fistulosa, and at lipped than at lipless flowers of M. didyma. The average duration of contact between a hummingbird and a flower's anthers and stigma was longer at M. didyma than at M. fistulosa for both lipped and lipless flowers, and at lipped than at lipless M. didyma flowers. Hummingbirds missed the openings of latex flowers with their bills more frequently and spent a greater percentage of their total feeding visit in error at (i) 2-mm than at 4-mm flowers of all three shapes, (ii) lipless flowers than at trumpet or lipped flowers, and (iii) lipped flowers than at trumpet flowers of both widths. The duration of hummingbird/anther contact was longer at (i) 2-mm than at 4-mm flowers of all shapes, (ii) lipped than at trumpet or lipless flowers, and (iii) lipless than at trumpet flowers for both widths. No significant differences in handling times of hummingbirds were observed among any of the latex flower shapes or widths. Our results demonstrate that orifice shapes can act as guides by reducing the frequency of feeding errors by visiting hummingbirds, and that effects of orifice shape on pollination must be considered in conjunction with flower widths and locations of anthers and stigmas.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00329706

    Articles: DFG German National Licenses