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2004

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Articles 481 - 496 of 496

Full-Text Articles in Physical Sciences and Mathematics

Seismic Stratigraphic Investigation Of The Ukpokiti Field Channel Complex, Oml 108, Offshore Nigeria, Northwestern Niger Delta, Toby Latwan Stewart Jan 2004

Seismic Stratigraphic Investigation Of The Ukpokiti Field Channel Complex, Oml 108, Offshore Nigeria, Northwestern Niger Delta, Toby Latwan Stewart

LSU Master's Theses

Detailed seismic stratigraphic analyses and mapping show that a well defined Ukpokiti Field Channel complex (late Miocene) found on the up-thrown side of a major back-to-back fault system in the West Niger delta inner-continental shelf probably formed during a single eustatic fall. The channel (>500 msec, 10 km wide) shows several tributaries entering the trunk axis from what was probably a surface of subaerial exposure. Slumping is prominent on the north flank of the trunk channel. No channel unconformity is evident in the down-thrown block. This investigation seeks to resolve the lack of down-dip correlative seismic expression across the …

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Wheatbelt Waterwise = Saltwise : Gardening Guide, John Colwill, Juana Roe Jan 2004

Wheatbelt Waterwise = Saltwise : Gardening Guide, John Colwill, Juana Roe

Bulletins 4000 -

As a result of agricultural clearing, many country towns are now feeling the effects of rising groundwater and the salt that it carries. Salinity has been identified as Australia’s number one environmental problem. While most people think that salinity means land lost to agriculture, it also poses a serious threat to many country towns. A report for the Department of Agriculture in 2001 highlighted the need for simple and cost-effective salinity management strategies to be adopted in wheatbelt towns. These included water recycling, revegetation and more efficient water use.

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Hydrologic Variations Within Created And Natural Wetlands In Southeastern Virginia, Aaron Dyer Despres Jan 2004

Hydrologic Variations Within Created And Natural Wetlands In Southeastern Virginia, Aaron Dyer Despres

OES Theses and Dissertations

The hydrology of wetlands, particularly how wetland soils collect, store, and redistribute water strongly affects how wetland systems function. In created wetlands, construction processes and materials influence the hydrology and consequently, the potential for successful reestablishment of target vegetation communities. During 2002–2004, the Virginia Department of Transportation constructed large mitigation wetlands on two different Quaternary aged surfaces with very similar hydrogeomorphic conditions. The Sandy Bottom Nature Park site (SBNP) located in Hampton, VA and rests on the sandy loam Tabb Formation while the Charles City Wetland site (CCW) lies on the older and clay-rich Shirley Formation. This study documents and …

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Estimation Of Primary Production And Carbon Flux In Antarctic Coastal Waters: A Modeling Study, Hae-Cheol Kim Jan 2004

Estimation Of Primary Production And Carbon Flux In Antarctic Coastal Waters: A Modeling Study, Hae-Cheol Kim

OES Theses and Dissertations

This study presents results from models that are designed to simulate the underwater light field, to simulate phytoplankton primary production, and to estimate the fate of phytoplankton carbon in continental shelf waters of the west Antarctic Peninsula (WAP) and Ross Sea. Simulation of the underwater light field required derivation of new coefficient sets for power function-type cloud cover correction algorithms, which were found to be influenced by multiple reflections between the bottom of clouds and the surface. The coefficient sets indicate that the spectral effect of clouds on the properties of the surface irradiance was spectrally-neutral for wavelengths greater than …

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An Investigation Of Dissolved Organic Matter In A Shallow Coastal Bay Subject To Aureococcus Anophagefferens Blooms, Jean-Paul Simjouw Jan 2004

An Investigation Of Dissolved Organic Matter In A Shallow Coastal Bay Subject To Aureococcus Anophagefferens Blooms, Jean-Paul Simjouw

OES Theses and Dissertations

Aureococcus anophagefferens, the pelagophyte responsible for brown tide blooms, was identified in Chincoteague Bay in 1997 and has “bloomed” there since at least 1998. Aureococcus anophagefferens is capable of using dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) substrates to support growth, and this utilization is hypothesized to give the organism a competitive advantage relative to other phytoplankton when inorganic nutrient concentrations are low or depleted. Because previous studies suggest dissolved organic matter (DOM) is important in initiating and sustaining brown tide blooms, a field study of the variations in DOC concentration and DOM composition was performed at …

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Rugose Corals Of The Livingston Limestone Member, Bond Formation, Coles And Edgar County, Illinois, John Tobias Burke Jan 2004

Rugose Corals Of The Livingston Limestone Member, Bond Formation, Coles And Edgar County, Illinois, John Tobias Burke

Masters Theses

No abstract provided.

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Arsenic In Nebraska's Groundwater And Public Water Supplies, David Gosselin, Lynne Klawer, Angela Noe Jan 2004

Arsenic In Nebraska's Groundwater And Public Water Supplies, David Gosselin, Lynne Klawer, Angela Noe

Department of Earth and Atmospheric Sciences: Faculty Publications

Because arsenic (As) in drinking water is considered a primary contributor to cancer in humans, the U.S. Environmental Protection Agency (EPA) recently lowered the maximum contaminant level (MCL) for arsenic from 50 micrograms per liter (μg/L) to 10 μg/L (1 μg/L ~ I part per billion: ppb). This MCL will become effective in 2006. On a national scale, EPA has estimated that of the 74,000 public water supply systems regulated by this MCL, approximately 4,000 systems will have to make changes to comply with it. Of the affected systems, 97 percent are small systems that serve fewer than 10,000 people …

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Temporal Variability In Nutrient Transport In A First-Order Agricultural Basin In Southern Ontario, Merrin L. Macrae Jan 2004

Temporal Variability In Nutrient Transport In A First-Order Agricultural Basin In Southern Ontario, Merrin L. Macrae

Theses and Dissertations (Comprehensive)

This thesis examines phosphorus and nitrate transport in a first-order agricultural catchment in Southern Ontario. Specific areas of concern relate to (1) long- and short-term temporal variability in nutrient export patterns, (2) the role of drainage tiles in annual nutrient export, (3) the effects of antecedent hydrologic conditions (AHC) on nutrient export patterns and (4) temporal variability in the nutrient retention in riparian buffer strips and streams. Temporal variability in hydrochemical export from the study basin over a two-year period is described and quantified and the importance of high magnitude events is highlighted. This is the first comprehensive study to …

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Nature And Dynamics Of Late Miocene/Early Pliocene Ice-Sheet Grounding Events On The Pacific Margin Of The Antarctic Pennisula Outer Continental Shelf, David C. Egan Jan 2004

Nature And Dynamics Of Late Miocene/Early Pliocene Ice-Sheet Grounding Events On The Pacific Margin Of The Antarctic Pennisula Outer Continental Shelf, David C. Egan

LSU Master's Theses

Package-3 unconformities identified by Bart and Anderson (1995) were mapped to evaluate their glacial unconformity interpretation using a regional grid of single channel seismic data from the Antarctic Peninsula outer continental shelf. Detailed correlations show many crosscutting relationships within Package 3 such that the unconformities and units they bound are not regionally continuous across the margin. Comparison of Package-3 unconformities with the modern bathymetry reveals that cross-shelf trough and bank morphology is absent, which indicates that ice streams probably did not exist on the shelf during Package-3 time. On the continental shelf, only the middle part of Package 3 is …

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Migmatization Of Archean Aluminous Metasediments From The Eastern Beartooth Mountains, Montana, U.S.A., Andrew T. Maas Jan 2004

Migmatization Of Archean Aluminous Metasediments From The Eastern Beartooth Mountains, Montana, U.S.A., Andrew T. Maas

LSU Master's Theses

Geothermobarometry, mineral compositions and textures, and thermodynamic models suggest biotite dehydration melting occurred in the peraluminous rocks of the eastern Beartooth Mountains. These Archean metapelitic migmatites are metatexites and diatexites, and have typical metamorphic assemblages of Qtz + Pl + Kfs + Bt + Sil +/- Grt +/- Crd. The subsequent in situ crystallization of the magma derived from the biotite dehydration created migmatitic leucosomes in the rocks. These leucosomes are primarily composed of quartz, plagioclase and potassium feldspar. Water derived from the dehydration of biotite was dissolved in the melted phase. Crystallization of the magma reintroduced this water to …

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Long-Range Downstream Effects Of Urban Runoff And Acid Mine Drainage In The Debed River, Armenia: Insights From Lead Isotope Modeling, Robert Kurkjian, Charles Dunlap, A. Flegal Dec 2003

Long-Range Downstream Effects Of Urban Runoff And Acid Mine Drainage In The Debed River, Armenia: Insights From Lead Isotope Modeling, Robert Kurkjian, Charles Dunlap, A. Flegal

Charles Dunlap

Lead concentrations and isotopic compositions measured along 80 km of the Debed River in the Republic of Armenia provide new insights into the geochemical and physical controls on riparian Pb transport by allowing comparison of the long-range, downstream impacts of acid mine drainage with runoff from an industrialized city. The modern background Pb concentration in Armenian surface waters is estimated to be ~0.01 lg/L, based on analyses of remote alpine rivers in Armenia. The lead concentration in the Debed River is 8 µg/L (800 times background) after passing through Vanadzor, the second largest industrial city in Armenia; it then decreases …

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Numerical Investigation Of Saturated Source Area Behavior At The Small Catchment Scale, Fred L. Ogden Dec 2003

Numerical Investigation Of Saturated Source Area Behavior At The Small Catchment Scale, Fred L. Ogden

Fred L. Ogden

The objective of this research is to explore the relationship between small catchment properties and the temporal growth and decay of saturated source areas (SSA). A simple physics-based hydrologic model, which we call the Sandbox model, is developed for this purpose. A thorough sensitivity analysis is undertaken to evaluate model response to variations in model parameters. Sandbox model output is compared to that from the semi-distributed conceptual model, TOPMODEL, a model with a wide spread acceptance. Plotting the temporal evolution of the extent of saturated source area versus catchment average soil water content dur- ing a number of wetting and …

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Toward A Climate Change Strategy For Pennsylvania, John C. Dernbach Dec 2003

Toward A Climate Change Strategy For Pennsylvania, John C. Dernbach

John C. Dernbach

No abstract provided.

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Lead In Residential Soil And Dust In A Mining And Smelting District In Northern Armenia: A Pilot Study, Varduhi Petrosyan, Anna Orlova, Charles E. Dunlap, Emil Babayan, Mark Farfel, Margrit Von Braun Dec 2003

Lead In Residential Soil And Dust In A Mining And Smelting District In Northern Armenia: A Pilot Study, Varduhi Petrosyan, Anna Orlova, Charles E. Dunlap, Emil Babayan, Mark Farfel, Margrit Von Braun

Charles Dunlap

This pilot study of sources of lead exposure in residential settings was conducted in a mining and smelting district in northern Armenia. Samples of exterior soil and dust and interior house dust were collected in and around apartment buildings in Alaverdi where the country’s largest polymetallic smelter is located, and in nearby mining towns of Aghtala and Shamlugh. The NITON XL- 723 Multi-Element XRF analyzer was used for lead testing. Lead levels in samples from Alaverdi were higher than those in Shamlugh and Aghtala. In all three towns, the highest lead levels were found in loose exterior dust samples, and …

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Introduction, Symposium Facing Climate Change: Opportunity And Tool For States, John C. Dernbach Dec 2003

Introduction, Symposium Facing Climate Change: Opportunity And Tool For States, John C. Dernbach

John C. Dernbach

No abstract provided.

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Making Sustainable Development Happen: From Johannesburg To Albany, John C. Dernbach Dec 2003

Making Sustainable Development Happen: From Johannesburg To Albany, John C. Dernbach

John C. Dernbach

No abstract provided.

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