323,821 research outputs found
Insight into the early steps of root hair formation revealed by the procuste1 cellulose synthase mutant of Arabidopsis thaliana
No full textBackground: formation of plant root hairs originating from epidermal cells involves selection of a polar initiation site and production of an initial hair bulge which requires local cell wall loosening. In Arabidopsis the polar initiation site is located towards the basal end of epidermal cells. However little is currently understood about the mechanism for the selection of the hair initiation site or the mechanism by which localised hair outgrowth is achieved. The Arabidopsis procuste1 (prc1-1) cellulose synthase mutant was studied in order to investigate the role of the cell wall loosening during the early stages of hair formation. Results: the prc1-1 mutant exhibits uncontrolled, preferential bulging of trichoblast cells coupled with mislocalised hair positioning. Combining the prc1-1 mutant with root hair defective6-1 (rhd6-1), which on its own is almost completely devoid of root hairs results in a significant restoration of root hair formation. The pEXPANSIN7::GFP (pEXP7::GFP) marker which is specifically expressed in trichoblast cell files of wild-type roots, is absent in the rhd6-1 mutant. However, pEXP7::GFP expression in the rhd6-1/prc1-1 double mutant is restored in a subset of epidermal cells which have either formed a root hair or exhibit a bulged phenotype consistent with a function for EXP7 during the early stages of hair formation. Conclusion: these results show that RHD6 acts upstream of the normal cell wall loosening event which involves EXP7 expression and that in the absence of a functional RHD6 the loosening and accompanying EXP7 expression is blocked. In the prc1-1 mutant background, the requirement for RHD6 during hair initiation is reduced which may result from a weaker cell wall structure mimicking the cell wall loosening events during hair formation
Alltagspraxis, Lebensweltkonstruktion und politische Selbstwahrnehmung in Zeiten der konsolidierten Personalunion zwischen Großbritannien und Hannover (1774–1783)
No full textSoftcover, 17x24Als Vertreter der britischen Krone war der Aufgabenbereich für die britischen Reichsdiplomaten im Dienste Georges III klar abgesteckt: Sie hatten sich um die britischen Belange zu kümmern, nicht aber um „His Majesty’s German Dominions“, unterhielt Kurhannover doch nach wie vor eigene Gesandtschaften. Theorie und Alltagspraxis erwiesen sich jedoch als nicht deckungsgleich.
Innerhalb des politischen Rahmens der konsolidierten Personalunion werden hier die (in)offiziellen Berührungspunkte britischer und hannoverscher Reichsdiplomatie in den Jahren zwischen 1774 und 1783 beleuchtet. Im Zentrum stehen dabei Angehörige des britischen Corps Diplomatique, die mittels ihres Schriftverkehrs Einblicke sowohl in ihre eigene Alltags- und Gedankenwelt als auch in die politisch-strukturelle Realität des Kommunikations- und Handlungsraumes der Personalunion zwischen Großbritannien und Hannover erlauben.British diplomats stationed in the German Empire and serving under George III had one major objective: seeing to matters regarding the British crown and steering clear of “His Majesty’s German Dominions”. The Electorate of Hanover did have her own diplomatic missions after all. As ever so often, theory deviated from reality and did indeed in this point.
Zoning in on British-Hanoverian (un)official collaboration and cooperation, a selection of British diplomats serving on the European continent between 1774 and 1783 take centre stage. It is through their eyes and writing that the political and structural realities of the British-Hanoverian union are illuminated. Moreover do they offer a unique insight into the political ideas and perceptions of those, for whom the British-Hanoverian union was more than a mere political backdrop
A Nebraska Specimen Record of Clark’s Grebe, \u3ci\u3eAechmophorus clarkii\u3c/i\u3e (Lawrence)
No full textClark’s Grebe, formerly known as light-phase Western Grebe (Aechmophorus occidentalis clarkii), was elevated to full species status (A. clarkii) in 1985 (American Ornithologists’ Union (AOU) 1983, 1985). This paper presents the first recorded occurrence in Nebraska of Clark’s Grebe and is documented with a specimen. Identification of Clark’s Grebe in the field is discussed, and a comparison is made of the Nebraska specimen with specimen s reported in recent literature
DDT homologues and PCBs in eggs of great crested grebe (Podiceps cristatus) and mallard (Anas platyrhynchos) from Lake Maggiore (Italy)
No full textDDT homologues and PCBs were determined in eggs of two stationary species, great crested grebe (Podiceps cristatus) and mallard (Anas platyrhynchos), in three breeding areas of Lake Maggiore in 1998. As expected, much higher contamination levels of both DDTs and PCBs were found in the fish-eating great crested grebe than in the mallard. In many eggs these values exceeded the safety thresholds proposed for aquatic bird protection. However, no significant correlation could be found between the two classes of pollutants and shell thickness in great crested grebe eggs. While a DDT manufacturer was detected as the main source of DDT pollution in the Lake Maggiore environment, the reason for the surprisingly high PCB level remains unknown
Automatengesteuertes skalierbares Verfahren zum Lastausgleich
No full textBeerbohm D, Bresken S, Hofestädt R, Huang X. Automatengesteuertes skalierbares Verfahren zum Lastausgleich. In: Flieger R, Grebe R, eds. Parallele Datenverarbeitung aktuell. Amsterdam: IOS Press; 1994: 100-108
Rallidae and Grebe species illustrations for an unpublished book on Australian birds [picture] /
No full textTitle devised by cataloguer from inscriptions and identification by researcher.; Part of collection: Watercolours for plates for an unpublished book on Australian birds by Gregory M. Mathews.; Inscriptions: "Lilian Medland"--In ink lower right; "Plate M1"--In ink on verso; "1/3 nat size"--In ink on verso.; Condition: Yellowing.; Also available online at: http://nla.gov.au/nla.pic-vn6183674. Paintings on card covered by transparent paper with traced and numbered outline of each bird. Bird species are depicted on the sheet. 1. Porzana fluminea (Australian Spotted Crake) 2. Poliolimnas cinereus (current name: Amaurornis cinereus, White-browed Crake) 3. Zapornia pusilla (current name: Porzana pusilla, Baillon’s Crake) 4. Crex crex (Corncrake) 5. Rallus pectoralis (current name: Lewinia pectoralis, Lewin’s Rail) 6. Amaurornis ruficrissa (current name: Amaurornis moluccana, Pale-vented Bush-hen) 7. Porzanoidea plumbea (current name: Porzana tabuensis, Spotless Crake) 8. Tomirdus tricolor (current name: Rallina tricolor, Red-necked Crake) 9. Hypotaenidia philippensis (current name: Gallirallus philippensis, Buff-banded Rail) 10. Poliocephalus novaehollandiae (breeding plumage) (current name: Tachybaptus novaehollandiae, Australasian Grebe) 11. Poliocephalus poliocephalus (Hoary-headed Grebe) 12. Poliocephalus novaehollandiae (current name: Tachybaptus novaehollandiae, Australasian Grebe) 13. Poliocephalus poliocephalus (breeding plumage) (Hoary-headed Grebe)--Identification key on verso
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Administración colonial y cultura escrita. Reflexiones acerca de las prácticas de poder y del papel de los archivos bajo Felipe II
No full textGrebe M-A. Administración colonial y cultura escrita. Reflexiones acerca de las prácticas de poder y del papel de los archivos bajo Felipe II. In: Thies S, Job B, eds. Colonialism and the Culture of Writing - Language and Cultural Contact in Colonial Discourse Traditions. Guadalajara; Submitted
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
\u3ci\u3eDiving Birds of North America\u3c/i\u3e: Color Plates
No full text1. Arctic loon, adult in breeding plumage. Photo by author. 2. Red-throated loon, nesting adult. Photo by Kenneth W. Fink. 3. Yellow-billed loon, adult in breeding plumage. Photo by Kenneth W. Fink. 4. Common loon, nesting adult. Photo by Kenneth W. Fink. 5. Pied-billed grebe, adult in breeding plumage. Photo by author. 6. Least grebe, adult and young. Painting by Mark E. Marcuson. 7. Red-necked grebe, nesting adult. Photo by author. 8. Eared grebe, adults with young. Photo by Kenneth W. Fink. 9. Horned grebe, nesting adult. Photo by Kenneth W. Fink. 10. Western grebe, adult with young. Photo by Gary Nuechterlein. 11. Downy young of grebes, including light (top left) and dark phases (top right) of western, black-necked (upper left), horned (middle left), least (lower left), red-necked (middle right), and pied-billed (lower right). Painting by Jon Fjeldså. 12. Dovekie, adult in breeding plumage. Photo by Frank S. Todd. 13. Razorbill, adult in breeding plumage. Photo by author. 14. Common murre, adult in winter plumage. Photo by author. 15. Thick-billed murre, adult in breeding plumage. Photo by author. 16. Black guillemot, adult in breeding plumage. Photo by Frank S. Todd. 17. Pigeon guillemot, breeding colony. Photo by Frank S. Todd. 18. Pigeon guillemots, immature plumage (left), rhinoceros auklet (middle), and common murre, breeding plumage (right). Photo by author. 19. Marbled murrelet, incubating adult. Photo by Stuart Johnson. 20. Kittlitz murrelet, incubating adult. Photo by David G. Roseneau. 21. Cassin auklet, immature plumage. Photo by author. 22. Parakeet auklet, adults in breeding plumage. Photo by author. 23. Crested auklet, adults in breeding plumage. Photo by author. 24. Crested and least auklets, adults in breeding plumage. Photo by author. 25. Least auklet, juvenal plumage. Photo by Frank S. Todd. 26. Whiskered auklet, juvenal plumage. Photo by C. Fred Zeillemaker. 27. Whiskered, least, and crested auklets, breeding adults. Painting by Mark C. Marcuson. 28. Rhinoceros auklet, adult in breeding plumage. Photo by Frank S. Todd. 29. Tufted puffin, adults in breeding plumage. Photo by author. 30. Atlantic puffin, breeding colony. Photo by Frank S. Todd. 31. Atlantic puffin, adult in breeding plumage. Photo by Frank S. Todd. 32. Horned puffin adults in breeding plumage. Photo by author
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