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 38 for “"seasonal distribution"”.
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A study of the seasonal distribution of Anopheles in Houston, Texas
… made, after the plotting of fluctuations in the seasonal abundance of the one common Anopheles of the region, Anopheles quadrimaculatus Say, to evaluate the various ecological factors involved in producing these fluctuations. It will be shown that the influence of some of these factors is of very …
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Temperature impact on reproduction and development of congener marine copepods: a key to distribution patterns?
… which differentiate in their geographical and/or seasonal distribution patterns, were investigated particularly with regard to temperature effects on population dynamics and distribution. In the field, reproduction was determined at two stations in the North Sea and the Mediterranean over several …
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The influence of hydraulics, hydrology and temperature on the distribution, habitat use and recruitment of threatened cyprinids in a Western Cape river, South Africa
… model of river ecosystems by examining the seasonal distribution of two endangered fish species, i.e. the Clanwilliam yellowfish and Clanwilliam sawfin, in relation to their physical (structural) and hydraulic habitat requirements at several scales, and to assess the importance temporal …
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Hydrologic sensitivities of western U.S. rivers to climate change
… will lead to fundamental changes in the seasonal distribution of streamflow, especially in the western United States where snowmelt plays a key role. These changes will inevitably lead to challenges for water resource managers. There is, however, considerable uncertainty as to the …
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The Ecology of Cuvier’s beaked whale, Ziphius cavirostris (Cetacea: Ziphiidae), in the Bay of Biscay
… introduces the habitat use and spatial-temporal distribution of Cuvier’s beaked whale (Ziphius cavirostris, Cuvier, 1823) in the Bay of Biscay, from surveys carried out by the Biscay Dolphin Research Programme between 1995 and 2007. I have analysed the spatio-temporal distribution of Cuvier’s …
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Analysis of the Benthic Macroinvertebrate Community Structure for Assessment of Water Quality of the Des Moines River
… was 2.19. Macroinvertebrate samples demonstrated seasonal distribution. Conclusions. Current velocity appeared to be a major factor controlling colonization of macroinvertebrates in this study. The mean species diversity value indicated the Des Moines River is mildly polluted. Standardized …
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ΒΙΟΣΤΑΤΙΣΤΙΚΗ ΔΙΕΡΕΥΝΗΣΗ ΤΗΣ ΘΝΗΣΙΜΟΤΗΤΑΣ ΣΤΗΝ ΕΛΛΑΔΑ, 1956-1982
… AGE AND SEX ANALYSIS, AND GEOGRAPHIC, URBAN AND SEASONAL DISTRIBUTION OF THE MORTALITY OF GREEK POPULATION WERE THE MAIN TASKS OF THE WORK. INFANT AND MATERNAL MORTALITY RECEIVED SPECIAL ATTENTION. THE STUDY WAS COMPLETED BY AN ANALYSIS OF CAUSES OF DEATH ACCORDING TO 9TH ICD IN CONNECTION ALSO …
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Hierarchical Variation in Cellulose Decomposition Across Southern Ontario Reference Streams
… ANOVAs, and comparisons of regional, habitat and seasonal differences were studied using a linear mixed effects model (LMEM). A partial least squares (PLS) regression analysis was performed to identify environmental variables associated with decomposition patterns. I found that variance associated …
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Investigations into some important fish larvae in the south east Atlantic in relation to the hydrological environment
… covered in the study: (i) the description of the seasonal hydrological changes in the survey area and a comparison between years. (ii) an examination of the seasonal distribution and abundance of the larval stages in relation to hydrological conditions. (iii) the determination of the preferential …
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Lake Sturgeon (Acipenser fulvescens) Population Attributes, Reproductive Structure, and Distribution in Namakan Reservoir, Minnesota and Ontario
… of gender and reproductive condition on seasonal distribution and movement patterns of lake sturgeon in the Namakan Reservoir. I evaluated year class strength and reproductive structure of lake sturgeon collected in the U.S. and Canadian waters of Namakan Reservoir. Reproductive structure …
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Distribution of Rotifera and Cladocera in a regulated river system
The purpose of this study was to determine distributions of Rotifera and Cladocera in the Kanawha River in West Virginia. Rotifera were sampled monthly for twelve months with a Juday trap in the more lotic upstream end of Winfield pool (UW), and the more lentic downstream end of Winfield pool (LW) …
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Characteristics of deep moist convection and rainfall in cut-off lows over South Africa
… surface circulation patterns at 850 hPa. The seasonal distribution and duration of the systems over northern (10°E-33°E //22°-32°S) and southern (10°E-33°E //32°-35°S) regions of the study area were also analyzed. Results show COL systems shifting with season towards the north eastern parts of …
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A comparative study of the syrphidae (diptera) from different habitats within Bernwood Forest
… between 1 April and 30 September 1980 - 1982. 2. Seasonal distribution is bimodal, with abundance peaks in May and late July through August. This contrasts with unimodal distribution in other habitats. Seasonal variation in aphid quality is proposed as the explanation. 3. Hoverfly species show …
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Control of Vibrio vulnificus and Vibrio parahaemolyticus in oysters
… and translucent, and V. parahaemolyticus have seasonal distribution, occurring mainly in the summer months when both V. vulnificus and V. parahaemolyticus are at elevated number in oysters. Transmission electron microscopy showed that the predominant morphology of bacteriophages against V. …
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Distribuição sazonal e espacial de uma comunidade de anfíbios anuros associada a uma lagoa temporária do Distrito da Lapinha, Lagoa Santa (MG)
… six (50,0%) represented the Hylidae family. The seasonal distribution revealed a successional process of reproductive activity among the species inhabiting the lake. It was possible to discriminate four pattems of temporal distribution: H. minuta and H. faber call during the wet and the dry …
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Simulation of the radiative flux at the martian surface between 180 and 1100 nm
… vapour are incorporated. Alternative aerosol distributions are also used corresponding to observations made by the Thermal Emission Spectrometer onboard Mars Global Surveyor.<br></br><br></br> Studies of the variation in surface flux in response to increasing dust optical depth predict reduced …
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Spatial and temporal variation in precipitation pattern
… in global water cycle and the corresponding redistribution of precipitation is a threat to food availability, stability, access and utilization. The droughts as well as floods have increased in number and scale. The effect of climate change can be seen by understanding the changes in trends of …
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Oceanic control of the sea ice edge and multiple equilibria in the climate system
… state. Multiple states persist despite a seasonal cycle and vigorous internal variability. Simulations with slowly-evolving thermal forcing show that some transitions between the ice-free and large ice cap states are abrupt. Multiple equilibria are explored in uncoupled simulations with …
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Particle-Water Interactions of Ni and Zn in Coastal Waters
… from the Humber coastal zone during six seasonal and inter-annual surveys (November 1993 - July 1995) on board RRS Challenger as part of the NERC Land Ocean Interaction Study (LOIS) initiative. Concentrations of Ni, Zn, Fe and Mn, extracted using a 1M HCl digest, were determined by atomic …
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China's food production under water and land limitations
… model predictions and represent diverse seasonal and regional patterns. Regionally, land is a limiting factor in the south, while water is a limiting factor in the north. Our results suggest that irrigation and multiple-cropping are keys in enhancing China's food production capacity to …
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