Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 77 for “"gastropod"”.
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Variations in shell form in the gastropod genus Diodora
Recent specimens of the genus Diodora from the Smithsonian Institution Mollusc Collection were examined for the neontological portion of this study. Species included were D. cayenensis, D. listeri, D. sayi, and D. tanneri. Fifty eight measurements were made on each specimen and recorded with …
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Multiscale mechanical studies of nacre from gastropod mollusk Trochus Nilocitus
(cont.) revealed jagged and branched crack fronts at plate interface, tortuous crack paths, non-uniform angles of polygons (suggesting possible intrinsic deformability and displacement/sliding). The technique of nanoindentation was carried out on individual aragonite tablets using a diamond-coated …
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A study of variation in the shell of the marine gastropod, purpura lapillus
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Biology, 1900.
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Reproductive traits of pioneer gastropod species colonizing deep-sea hydrothermal vents after an eruption
… to study the reproductive traits of two pioneer gastropod species, Ctenopelta porifera and Lepetodrilus tevnianus, presented itself in 2006 after an eruption on the East Pacific Rise (EPR) eliminated vent communities near 9°50ʹ′N. Standard histological techniques were used to determine whether …
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Biodiversity and Biogeography of Deep-Sea Gastropod Mollusks from the Pacific Costa Rica Margin
… the diversity and biogeography of deep-sea gastropod mollusks from hydrocarbon seeps at the Pacific Costa Rica Margin to understand what factors lead to the generation and maintenance of novel biodiversity at chemosynthesis-based ecosystems in the ocean. The Pacific Costa Rica Margin was …
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Reproductive traits of pioneer gastropod species colonizing deep-see hydrothermal vents after an eruption
… to study the reproductive traits of two pioneer gastropod species, Ctenopelta porfera and Lepetodrilus tevnianus, presented itself in 2006 after an eruption on the East Pacific Rise (EPR) eliminated vent communities near 9°50'N. Standard histological techniques were used to determine whether …
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Biochemical and morphological systematics of the Southern African gastropod genera Burnupena (Buccinidae) and Oxystele (Trochidae)
Gastropods of the genus Burnupena are very common rocky-shore whelks endemic to the Southern African region. However, despite recent revisions of the genus, difficulties in identification persist, due mainly to the occurrence of phenotypic intermediates between sympatric species. Samples of …
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Fracture of the interlayer junction of the shell from a deep-sea hydrothermal vent gastropod
There is considerable amount of interest in the hierarchical nanomechanical processes that contribute to property amplification of biomaterials. An investigation of these processes and the quantification of the mechanical properties and structure of a biomaterial multilayer is determined. The …
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The effects of mass extinction on escalation of the naticid gastropod predator-prey system at the Eocene-Oligocene
<p> In 1987, Vermeij proposed the hypothesis of escalation, which states that biological hazards, such as predation, have increased through the Phanerozoic. This hypothesis has been extremely controversial due to the fact that it assumes that biotic factors, such as predation, have had an important …
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Population Biology and Landscape Ecology of Digenetic Trematode Parasites in their Gastropod Hosts, with Special Emphasis on Echinostoma spp.
… dynamics of trematode larval stages in their gastropod hosts. Allogenic parasites, particularly those cycling through waterfowl, have distinct seasonal trends in their infection patterns in gastropod first intermediate hosts due to their ephemeral nature, while autogenic species exhibit …
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Hitching a ride: A gastropod-associated microbiome community at a Hydrate Ride methane seep and impacts on local biogeochemical cycling
… microbial communities associated with provannid gastropods as characterized using 16S rRNA gene amplicon and clone libraries as well as Fluorescence In Situ Hybridization. The gastropod shells, collected from seeps at Hydrate Ridge and the Gulf of Mexico are covered with filamentous epibionts on …
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Direct Measurements of the Effects of Cyclic Adenosine Monophosphate, and Related Compounds, on Membrane Conductances, Intracellular Calcium and Ph in Gastropod Neurons (cyclic-Amp)
… related compounds were examined in identifiable gastropod neurons. Injecting cyclic AMP (or cyclic GMP) in amounts which should have elevated the internal concentration from 0.1-7.6 mM (mean = 3.3 mM) resulted in transient depolarizations of the cells lasting several minutes. These injections …
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Aromatic alcohol oxidase, aldehyde oxidase and mannitol oxidase in terrestrial gastropods
… in the alimentary tissues of terrestrial gastropod molluscs. A membrane-bound aromatic alcohol oxidase activity has been demonstrated in the digestive gland (hepatopancreas) of four families of gastropod (Arionidae, Limacidae, Helicidae and Achatinidae). Aromatic alcohol oxidase activity …
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Influence of hydrodynamics on the larval supply to hydrothermal vents on the East Pacific Rise
… genetic identifications for hydrothermal vent gastropod larvae along the northern East Pacific Rise. Daily and weekly variability in the supply of hydrothermal vent gastropod larvae to two hydrothermal vents, 1.6 km apart on the East Pacific Rise, were quantified concurrently with current …
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Biophysical coupling between turbulence, veliger behavior, and larval supply
… of this thesis were to quantify the behavior of gastropod larvae (mud snails Ryanassa obsoleta) in turbulence, and to investigate how that behavior affects larval supply in a turbulent coastal inlet. Gastropod larvae retract their velums and sink rapidly in strong turbulence. Turbulence-induced …
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Estudo da concha, rádula, mandíbula, câmara palial e sistema reprodutor de Thaumastus (Thaumastus) magnificus (Grateloup, 1839) (Mollusca, Gastropoda, Stylommatophora, Bulimulidade)
… geographical distribuition, of the terrestrial, gastropod Thaumastus (Thaumastus) magnificus (Grateloup, 1839). It is concluded that shell and body morphology characterize the species distinguishing it from Thaumastus (T.) taunaisii (Férussac, 1822).
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Biophysical coupling between turbulence, veliger behavior, and larval supply
… of this thesis were to quantify the behavior of gastropod larvae (mud snails Ilyanassa obsoleta) in turbulence, and to investigate how that behavior affects larval supply in a turbulent coastal inlet. Gastropod larvae retract their velums and sink rapidly in strong turbulence. Turbulence-induced …
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