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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Transport of zooplankton in South Slough, Oregon

Puls, Amy L. January 2002 (has links)
Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 90-96). Description: xii, 96 leaves : ill. ; 29 cm.
82

Gametogênese e desenvolvimento embrionário de Nausithoe aurea (Scyphozoa, Coronatae) do canal de São Sebastião - SP. / Gametogenesis and embryonic development of Nausithoe aurea (Scyphozoa, Coronatae) from the São Sebastião Channel - SP.

André Carrara Morandini 13 September 1999 (has links)
Nausithoe aurea Silveira & Morandini, 1997 é uma espécie metagenética e dióica com fecundação externa. Os oócitos são liberados continuamente (55 dias em laboratório), porém com grandes variações no número a cada dia. No desenvolvimento embrionário a clivagem, após o estágio de 8 células, passa de holoblástica e igual para pseudoespiral. A gastrulação ocorre por ingressão multipolar e inicia-se aproximadamente 24 horas após a fecundação. A estrutura histológica geral das gônadas assemelha-se a outros Scyphozoa, onde os gonócitos proliferam a partir da gastroderme, migram e diferenciam-se na mesogléia. Na gônada masculina as células germinativas formam camadas razoavelmente distintas e constituem folículos testiculares. Na gônada feminina os oócitos surgem da zona germinativa na gastroderme e apresentam um gradiente de maturação a partir deste ponto (cortes no sentido oral-aboral). Os oócitos encontram-se livres na mesogléia da gônada, sem associação com outras células. A relação espacial entre a musculatura circular, as gônadas e o sulco coronal, é uma característica a ser usada na sistemática do gênero Nausithoe Kölliker, 1853. / Nausithoe aurea Silveira & Morandini, 1997 is a metagenetic and dioecious species with external fertilization. The oocytes are released continuously (55 days in laboratory), but with great variations in the daily number. In the embryonic development the cleavage, after the 8 cells stage, changes from holoblastic and adequal to pseudospiral. The gastrulation occurs through multipolar ingression and begin 24 hours after fertilization. The general histological structure of the gonads resembles other Scyphozoa, in which the gonocytes proliferate from the gastrodermis, migrate and differentiate in the mesoglea. In the male gonad the germ cells are arranged in distinctive layers and form follicles (cysts). In the female gonad the oocytes develop from the germinative zone in the gastrodermis and present a maturing gradient from this point on (oral-aboral sections). The oocytes are free in the gonad mesoglea, without association to any cell. The spatial relation of the coronal musculature, gonads and coronal groove, is a character to be used in the systematics of the genus Nausithoe Kölliker, 1853.
83

Osteologische Untersuchungen an rezenten Tierknochen aus der Küstensiedlung Caletones auf Kuba: Ein Beitrag zur Ethnoarchäologie

Frisch, Hans-Jörg, Teegen, Wolf-Rüdiger 29 May 2019 (has links)
In diesem Beitrag wird über osteologische Untersuchungen an rezenten Knochenfunden aus der kubanischen Strandsiedlung Caletones berichtet. Außer den Haustierarten Rind, Schaf/Ziege, Schwein und Huhn wurden Knochen von mindestens zwei Meeresschildkrötenarten und von zwei bislang unbestimmten Fischarten gefunden. Marine Tiere spielen in der Ernährung der Küstenbewohner eine wichtige Rolle. Spuren krankhafter Veränderungen wurden ausschließlich an den Schweineschädeln festgestellt und betreffen hauptsächlich Kiefer und Zähne. / This paper describes the recent bone finds from the Cuban coastal village Caletones. Bones of domestic animals (cattle, sheep/goat, pig, chicken) as well as sea turtles were present. Furthermore, bones of two, not yet determined, fish species were found. Marine animals provide an important part of animal protein for the coastal population in Cuba. Pathological changes were only found in the skulls of pigs and are mainly related to the teeth and jaws.
84

CCAAT/Enhancer-Binding Protein Delta (C/EBP-delta) Expression in Antarctic Fishes: Implications for Cell Cycle and Apoptosis

Sleadd, Isaac Martin 13 August 2013 (has links)
Chapter 1: Antarctic fishes are extremely cold adapted. Despite their inability to upregulate heat shock proteins, recent studies have demonstrated a capacity for heat response in these animals. A cDNA microarray study looked at the Notothenioid fish Trematomus bernacchii and revealed heat sensitivities for hundreds of genes, two of which code for members of the CCAAT/Enhancer-binding protein (C/EBP) family of transcription factors. These molecular switches are best known for their roles in apoptosis, inflammation and cell cycle arrest. This dissertation further elucidates the role of C/EBP-delta in the Antarctic fishes T. bernacchii and Pagothenia borchgrevinki. Chapter 2: C/EBP-delta is constitutively expressed in unstressed, field-acclimated (ca. -1.86°C) animals in a highly tissue-specific manner. White muscle tissue contains the highest C/EBP-delta concentration, which is further increased in response to sublethal heat stress at 2.0 or 4.0°C. This response is mostly acute and transitory, but a lesser upregulation was observed in fishes held for one month at 4.0°C. Chapter 3: The heat-induced nuclear translocation of C/EBP-delta--as determined by immunohistochemistry--appears to be time, tissue and species specific with spleen, heart and retinae being particularly responsive in certain situations. Chapter 4: Protein concentrations of proliferating cell nuclear antigen are tissue specific and variably heat responsive. Surprisingly, levels appear to be positively correlated with C/EBP-delta. Chapter 5: Flow cytometry revealed increasingly high temperatures reduce the proportion of G1 cells while increasing the abundance of apoptotic cells. Chapter 6: These findings are discussed in the context of global climate change and the cellular stress response.
85

A Parabolic Equation Analysis of the Underwater Noise Radiated by Impact Pile Driving

Laws, Nathan 05 July 2013 (has links)
Impact pile driving can produce extremely high underwater sound levels, which are of increasing environmental concern due to their deleterious effects on marine wildlife. Prediction of underwater sound levels is important to the assessment and mitigation of the environmental impacts caused by pile driving. Current prediction methods are limited and do not account for the dynamic pile driving source, inhomogeneities in bathymetry and sediment, or physics-based sound wave propagation. In this thesis, a computational model is presented that analyzes and predicts the underwater noise radiated by pile driving and is suitable for shallow, inhomogeneous environments and long propagation ranges. The computational model uses dynamic source models from recent developments in the technical literature. Pile source models are coupled to a broadband application of the range-dependent acoustic model (RAMPE), a standard parabolic equation (PE) propagation code capable of modeling wave propagation through complex, range dependent environments. Simulation results are shown to be in good agreement with several observations of pile driving operations in the Columbia River between Portland, Oregon and Vancouver, Washington. The model is further applied to extend sound level predictions over the entire river and study the effects of sediment and bathymetry on the underwater sound levels present in the environment.
86

Dietary responses of marine predators to variable oceanographic conditions in the Northern California Current

Gladics, Amanda J. 16 April 2012 (has links)
Variable ocean conditions can greatly impact lower trophic level prey assemblages in marine ecosystems, with effects propagating up to higher trophic levels. Our goal was to better understand how varying ocean conditions influence diets and niche overlap among a suite of low- to mid trophic level predators. We studied the diets of common murres (Uria aalge) over 10 contrasting years between 1998 and 2011, a period in which the Northern California Current experienced dramatic interannual variability in ocean conditions. Likewise, murre diets off Oregon varied considerably. Interannual variation in murre chick diets appears to be influenced by environmental drivers occurring before and during the breeding season, at both basin and local spatial scales. While clupeids were an important diet component throughout the study period, in some years murre diets were dominated by Pacific sand lance (Ammodytes hexapterus) and other years by osmerids (likely Allosmerus elongatus and Hypomesus pretiosus). Years in which the Pacific Decadal Oscillation and local sea surface temperatures were above average during summer months also showed elevated levels of clupeids in murre diets, while years with higher winter ichthyoplankton biomass and summer northern copepod biomass anomalies had fewer clupeids and more sand lance and smelts. Years with higher Northern Oscillation Index values during summer months also showed more smelts in the murre diets. Nesting phenology and reproductive success were correlated with diet as well, reflecting demographic consequences of environmental variability mediated through bottom-up food web dynamics. To examine niche overlap between murres and other marine predators we employed collaborative fisheries research with synoptic observations of a major seabird colony to determine the diets of four predator species on the central Oregon coast during two years of contrasting El Niño (2010) vs. La Niña (2011) conditions. The greatest degree of dietary overlap was observed between Chinook salmon (Oncorhynchus tshawytscha) and common murres, with both smelts (Osmeridae) and clupeids (primarily Clupea pallasii) observed as the dominant prey types. Diets differed between El Niño and La Niña conditions for two predators, murres and black rockfish (Sebastes melanops). During La Niña, smelts decreased, while sand lance increased in common murre diets. Black rockfish had fewer larval Dungeness crabs (Cancer magister) and a greater proportion of crab species associated with the later spring transition. Chinook salmon and Pacific halibut (Hippoglossus stenolepis) diets were similar during El Niño and La Niña conditions. These findings underscore that the diets of common murres during chick rearing reflect local- and basin-scale biophysical processes in the Northern California Current, and are valuable for understanding the response of upper trophic level organisms to changing oceanographic conditions. Additionally, using multiple predators across several diverse taxa to track changes in prey communities provided a way to detect seemingly subtle changes in prey communities and contributes to a more comprehensive understanding of food web dynamics and ecosystem indicators. / Graduation date: 2012
87

Kretische Tongefässe mit Meeresdekor Entwicklung und Stellung innerhalb der Feinen Keramik von Spätminoisch I B auf Kreta /

Müller, Walter. January 1900 (has links)
Revision of the author's Thesis (doctoral)--Universität Mannheim, 1985. / At head of title: Deutsches Archäologisches Institut. Includes bibliographical references (p. 13-16) and index.
88

Kretische Tongefässe mit Meeresdekor Entwicklung und Stellung innerhalb der Feinen Keramik von Spätminoisch I B auf Kreta /

Müller, Walter. January 1900 (has links)
Revision of the author's Thesis (doctoral)--Universität Mannheim, 1985. / At head of title: Deutsches Archäologisches Institut. Includes bibliographical references (p. 13-16) and index.

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