Showing 2041 - 2050 of 5708 Items
500 Years of Printmaking: Prints and Illustrated Books at Bowdoin College
Date: 1978-01-01
Creator: David P. Becker
Access: Open access
- Exhibition held Oct. 13-Dec. 31, 1978. Preface by Katherine J. Watson.
Evolution of the interaction between Hox genes and a downstream target
Date: 1998-05-07
Creator: Michael F. Palopoli, Nipam H. Patel
Access: Open access
- Segmental identifies along the insect body depend on the activities of Hox genes [1,2]. In Drosophila melanogaster, one well-studied Hox regulatory target is Distal-less (DII), which Is required for the development of distel limb structures [3]. In abdominal segments, DII transcription is prevented when Hox proteins of the Bithorax Complex (BX-C) bind to cis-regulatory elements upstream of the DII transcription start site [4,5]. Previous evolutionary comparisons of gene expression patterns suggest that this direct repression is conserved between Diptera and Lepidoptera, but is absent in the Crustacea [6,7]. We examined gene expression patterns in three orders of hexapods, all of which develop abdominal appendages, in order to determine when the strong repressive interaction between BX-C proteins and DII appeared during evolution. In each of the species examined, DII expression was initiated in abdominal cells despite the presence of high levels of BX-C proteins. It appears that the strong repressive effects of BX-C proteins on DII expression arose relatively late in insect evolution. We suggest that the regulatory interaction between the BX-C genes and DII has evolved within the hexapods in a complex, segment-specific manner.
The Politics of Land Rights in the Transition to Democratic South Africa: The Rise and Fall of the Constitutional Property Clause
Date: 2019-05-01
Creator: Anna Louisa Roosevelt Lennon
Access: Open access
Lipschitzian multifunctions and a Lipschitzian inverse mapping theorem
Date: 2001-01-01
Creator: A.B. Levy
Access: Open access
Interest groups in electoral politics: 2012 in context
Date: 2012-12-01
Creator: Michael M. Franz
Access: Open access
- This paper compares the levels of ad spending from outside groups and traditional party organizations across seven federal election cycles. The data show clearly that outside groups advertised at historic levels in 2012. Such intense efforts send two important signals to students of American campaign finance. The first involves a crisis in the system of limited donations to candidates and party committees moving forward. The second resurrects an old debate in political science about whether parties or candidates should be the center of our electoral process. The paper concludes with a consideration of possible reforms that might help restore parties and candidates to the center of issue debates in competitive federal elections.
Collecting Privately
Date: 1965-01-01
Access: Open access
- Exhibition catalogue from Bowdoin College Museum of Art.
Peatlands and their role in the global carbon cycle
Date: 2011-04-20
Creator: Zicheng Yu, D. W. Beilman, S. Frolking, G. M. MacDonald, N. T., Roulet, P. Camill, D. J. Charman
Access: Open access
- Global peatlands store a very large carbon (C) pool located within a few meters of the atmosphere. Thus, peatland-atmosphere C exchange should be a major concern to global change scientists: Will large amounts of respired belowground C be released in a warmer climate, causing the climate to further warm (a positive climate feedback)? Will more C be sequestered due to increased plant growth in a warmer climate? How will land use change, fires, and permafrost thaw affect the magnitude and direction of carbon dioxide (CO ) and methane (CH ) exchange with the atmosphere? These questions remain challenging, but some significant progress has been made recently. 2 4