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Feeding Ecology and Territorial Behavior of the Yellow WarblerFrydendall, Merrill J. 01 May 1967 (has links)
A controversy dating from the appearance of Altum's book, Der Vogel und sein Leben, 1868 (Mayr, 1935) is that of the biological function or functions of the territorial behavior in birds. However, attention was not focused upon this problem until the advent of Howard's book, Territory in Bird Life, published in 1920. In a general review of the problem Hinde (1956) discussed several functions of the territory and presented evidence both for and against their importance. The more important of these presumed functions are; (1) limitation of population density; (2) facilitation of pair formation and maintenance of the pair bond; (3) reduction in interference with reproductive activities by other members of the species; (4) provision of an adequate food supply for rearing the young; (5) reduction of loss to predators; (6) reduction of time spent in aggression; and (7) prevention of epidemics.
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Two new roles for the TYMV tRNA-like structure : translation enhancement and repression of minus strand synthesisMatsuda, Daiki 27 January 2004 (has links)
Some positive-strand RNA plant viruses possess a transfer RNA-like structure
(TLS) at the 3'-terminus of their genomic RNAs. The closest mimicry to tRNA is
exhibited by the valylatable TLSs from tymoviruses and furo-like viruses, which are able
to interact with key cellular tRNA enzymes: [CTP, ATP]:tRNA nucleotidyltransferase
(CCA NTase), valyl-tRNA synthetase (ValRS), and translation elongation factor 1A
(eEF1A). In this thesis, I report the discovery of two new roles of the Turnip yellow
mosaic tymovirus TLS, in translation enhancement (Chapter 2) and repression of minus
strand initiation (Chapter 4).
Placement of the 3'-terminal 109 nts of TYMV RNA in a luciferase reporter RNA
with a generic 5'-UTR enhanced translation by about 20-fold in cowpea protoplasts.
Exhibiting a synergistic relationship with the 5'-cap, the 3'-translation enhancement was
largely dependent on the aminoacylatability of the TLS and apparently on eEF1A
interaction. In the presence of the 5'-UTR from genomic TYMV RNA, translation of
both the overlapping proteins p69 and p206 was strongly dependent on a 5'-cap structure,
and was enhanced by the 3'-enhancer. These in vivo results contradict the proposed
model in which translation initiation of p206, but not p69, is cap-independent and TLS-dependent (Barends et al. Cell 112(2003):123-9).
In vitro experiments with a partially purified preparation of TYMV replicase have
investigated the phenomenon of minus strand repression. Interaction of purified
eEF1A���GTP specifically with the valylated TLS decreased the template activity for
minus strand to near-background levels. eEF1A���GTP acts by making the 3'-CCA minus
strand initiation site unavailable to the replicase. The influence of eEF1A in
simultaneously enhancing translation and repressing minus strand synthesis can be
considered a regulation that ensures robust translation early in the infection and that
offers a coordinated transition from translation to replication.
Previously shown to be critical for TYMV infectivity, a valylatable TLS was
investigated for its role in the replication and infectivity of the bipartite Peanut clump
pecluvirus. A valylatable TLS provided a small competitive advantage in protoplasts and
whole plants. The advantage was more apparent in protoplasts than in whole plants, and
more so in the replication protein-encoding RNA1 than in the trans-replicating RNA2. / Graduation date: 2004
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The Philadelphia pestilence of 1793Quebbeman, Frances E. January 1961 (has links)
No description available.
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The effect of nitrogen and phosphorus on the early development of Pinus ponderosa Laws, seedlings in soil and sand cultures under greenhouse conditionsPotter, John Richard, 1939- January 1964 (has links)
No description available.
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The effects of shading and planting depth treatments on the germination and survival of ponderosa pineBerglund, Erwin R. January 1967 (has links)
No description available.
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Life history responses of yellow perch (Perca flavescens) to mass removalNg, Rebecca Yuen Wah, 1977- January 2005 (has links)
This study evaluates the life history responses of yellow perch to mass removal and the potential for population recovery. We removed approximately 94% of a perch population from Nepawin Lake, a 35 hectare oligotrophic lake in Algonquin Provincial Park, Ontario, as part of a study designed to enhance the recruitment success of brook trout. Several response variables were examined both before and after mass removal: (1) condition, which includes growth, diet and overall condition responses, and (2) reproduction, which includes size at maturity and fecundity. We examine the question of whether compensatory life history responses in the yellow perch will overcome brook trout predation leading to a reestablishment of a high density perch population. Results showed that prior to the manipulation, perch exhibited a narrow size distribution, high dietary overlap, and low condition, typifying a stunted population. After mass removal, the perch population remained in a narrow size distribution, exhibited decreased growth rates for older age classes, showed increased mean condition and increased consumption of zooplankton in all size classes. Perch also exhibited increased size at maturity and decreased fecundity immediately following the mass removal. A time lag is expected before compensatory recruitment is possible in the population, but it is likely that the perch will recover from the mass removal because of strong age 0+ and 1+ cohorts. However, stunting and bottlenecking may still occur in the population. Continued monitoring and management is necessary to observe further changes to the perch population dynamics in Nepawin Lake.
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Studies on the molecular biology of wild-type and attenuated strains of Japanese encephalitis virusNi, Haolin January 1994 (has links)
No description available.
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Food habits and prey size-selection of yellow perch in extreme southern Lake Michigan, with emphasis on the prey : round gobyTruemper, Holly A. January 2003 (has links)
Food habits for yellow perch Perca flavescens were compared using current and previous diet studies from southern Lake Michigan index sites. Yellow perch were not gape limited but size-selective in consumption of the newly established round goby Neogobius melanostomus. Ingested fish ranged from 7 to 47% of the yellow perch's total length and 2 to 53% of their gape. Currently, yellow perch diets are dominated in volume by fish/fish products (85%), which is double from previous studies. Utilization of zooplankton and insect prey items in the yellow perch diet has decreased to <1% by volume in 2002, contrasting with previous consumption of 4 to 20% and 5 to 17%, respectively, from previous studies during 1971-1993. Yellow perch are exhibiting opportunistic, generalist feeding strategy that incorporates both exotic and native prey items, allowing the population to use multiple prey items with the changing prey base in Lake Michigan. / Department of Biology
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Nucleotide sequence homology within two subgroups of the potyviruses / by Norani Abu SamahAbu Samah, Norani Binti January 1982 (has links)
Typescript (photocopy) / xii, 107 leaves, [11] leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Dept. of Agricultural Science, University of Adelaide, 1982
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The ecology of the aphid Hyperomyzus lactucae (L) and the epidemiology of lettuce necrotic yellows virus / David K. MartinMartin, David Keith January 1979 (has links)
Typescript (photocopy) / iv, 206 leaves, [4] leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Entomology, 1980
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