Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 5461 - 5490 of 6139

Full-Text Articles in Entire DC Network

The Use Of Stable Isotopic Signatures Of Marine Biota To Map Sewage Effluent Disposed Into The Marine Environment, Adam Gartner Jan 2000

The Use Of Stable Isotopic Signatures Of Marine Biota To Map Sewage Effluent Disposed Into The Marine Environment, Adam Gartner

Theses : Honours

Recent work indicates that nitrogen stable isotopic signatures of aquatic biota can be used to link nutrient inputs in the marine environment to terrestrial sources. While this technique of tracing nutrients has been shown to be effective in environments that are not nutrient limited, it has not been proved that this method is effective in oligotrophic environments. This study examined whether nitrogen stable isotopic signatures of marine biota can be used to trace the distribution of sewage effluent in highly mixed, nitrogen limited waters, by examining the δ15N values of marine biota situated close to and distant from …


Geomorphometry – Diversity In Quantitative Surface Analysis, Richard J. Pike Jan 2000

Geomorphometry – Diversity In Quantitative Surface Analysis, Richard J. Pike

United States Geological Survey: Staff Publications

A widening variety of applications is diversifying geomorphometry (digital terrain modelling), the quantitative study of topography. An amalgam of earth science, mathematics, engineering and computer science, the discipline has been revolutionized by the computer manipulation of gridded terrain heights, or digital elevation models (DEMs). Its rapid expansion continues. This article reviews the remarkable diversity of recent morphometric work in 15 selected topics and discusses their significance and prospects. The quantitative analysis of industrial microsurface topography is introduced to the earth science community. The 14 other topics are Internet access to geomorphometry; global DEMs; DEM modelling of channel networks; …


The Growth And Distribution Of The Green Alga Cladophora At Presqu'ile Provincial Park: Implications For Management (Ontario), Dolf Craig Dejong Jan 2000

The Growth And Distribution Of The Green Alga Cladophora At Presqu'ile Provincial Park: Implications For Management (Ontario), Dolf Craig Dejong

Theses and Dissertations (Comprehensive)

The Green alga genus Caldophora is one of the most abundant kinds of algae worldwide, found in both freshwater and marine environments. It prefers nutrient-rich waters and requires a rocky substrate and water movement for growth. When water temperatures reach 22 to 26 C, the alga dies and washes into shore in large mats. Dead Cladophora produces a terrible odour, reduces property values and can alter the taste of drinking water. At Presqu’ile Provincial Park, maximum Cladophora sloughing occurred July 22 1999, the same time as peak summer park visitation begins. This results in the fouling of the Park’s beaches …


The Management Of Complex Sociobiophysical Systems: Ecosystem-Based Management And The Chesapeake Bay Program, Daniel Dennis Mccarthy Jan 2000

The Management Of Complex Sociobiophysical Systems: Ecosystem-Based Management And The Chesapeake Bay Program, Daniel Dennis Mccarthy

Theses and Dissertations (Comprehensive)

There are an entire class of entities for which conventional scientific understanding is necessary but not sufficient to comprehend. These entities are too complex for analysis and yet too organized for statistics. They exist in a dynamic balance between the ordered and the disordered. They are ecosystems and human institutions. They are complex systems. There is an emerging body of theory that is providing insight into the structures and dynamics that underlie such entities. Under the rubric of complex systems theory, catastrophe theory, chaos theory, hierarchy theory and the interrelated theories of self-organization have profound implications for the way understand …


Killbear Provincial Park: The Beach And Dunes, Their Use And The Implications For Management (Ontario), Kathryn Ann Parlee Jan 2000

Killbear Provincial Park: The Beach And Dunes, Their Use And The Implications For Management (Ontario), Kathryn Ann Parlee

Theses and Dissertations (Comprehensive)

Beaches, and in particular sand dunes, are extremely fragile environments, easily altered by human activities. Intensive use of the beach/dune complex at Killbear Provincial Park near Parry Sound, Ontario may have led to the severe degradation of its dune system within Kilcoursie Bay. At present the dunes have been degraded back to an embryonic state, and as a result it is necessary to consider the development of management strategies before the system is completely destroyed. In order to develop effective management strategies however, it is necessary to understand how the natural process of the system work and the specific effects …


Examination Of The Role Of Macropores And Subsurface Drainage In The Delivery Of Nitrogen Trioxide-Nitrogen To A Small First-Order Agricultural Stream In Southern Ontario, Abraham House Jan 2000

Examination Of The Role Of Macropores And Subsurface Drainage In The Delivery Of Nitrogen Trioxide-Nitrogen To A Small First-Order Agricultural Stream In Southern Ontario, Abraham House

Theses and Dissertations (Comprehensive)

Agricultural practices may result in nitrate losses, diminished surface water quality and widespread groundwater aquifer contamination. Many works have identified preferential flow through macropores as an important feature that may increase nitrate losses. Subsurface drainage collectors may intercept preferential flow and indicate changing unsaturated/saturated processes. Antecedent conditions are important in determining runoff response. It is unclear how tile drains modify the antecedent soil moisture regime and water tables in near stream areas. Vegetated riparian buffer zones found beetween agricultural fields and watercourses may attenuate nitrate in shallow groundwater pathways. However, little work recognizes the close proximity of buffer strips and …


Identifying Areas Of Concern For Regional Cumulative Effects Assessments In And Around Northern National Parks In Canada (Yukon), Jennifer L. Lenton Jan 2000

Identifying Areas Of Concern For Regional Cumulative Effects Assessments In And Around Northern National Parks In Canada (Yukon), Jennifer L. Lenton

Theses and Dissertations (Comprehensive)

This thesis uses a literature review of protected areas selection, park management, comprehensive regional land use planning, and cumulative environmental effects and assessment to develop a methodology that identifies areas with concentrations of social and/or ecological values in and around northern national parks. The proposed methodology involves two stages. First, a database of values is developed by taking an inventory of social and ecological values through exxtensive literature reviews, interviews, and consultation with the public. This database is then used in the second step to determine areas with concentrations of social and/or ecological values, or “value hotspots”, using a series …


Spatial And Temporal Patterns Of Fluvial Suspended Sediment Yield From Eastern North America, Catherine Treena Conrad Jan 2000

Spatial And Temporal Patterns Of Fluvial Suspended Sediment Yield From Eastern North America, Catherine Treena Conrad

Theses and Dissertations (Comprehensive)

A knowledge of spatial and temporal patterns of sediment yields and an understanding of the factors that determine those patterns have theoretical, environmental and socio-economic significance. To assess the change in sediment yields (in both space and time) a data base of 193 river gauging sites spanning the eastern provinces of Canada and eastern United States was compiled. The original source of the data was the United States Geological Survey data base (obtained from a Hydrosphere Data Inc. cd-rom) and Environment Canada (HYDAT) data base, which included stream discharge, sediment loads and basin areas, with record lengths of one year …


Intelligent Visualization And Automated Processing For Large Scale Geographic Information Systems, Yu Jiang Dec 1999

Intelligent Visualization And Automated Processing For Large Scale Geographic Information Systems, Yu Jiang

All-Inclusive List of Electronic Theses and Dissertations

This research focuses on developing a new output system that compacts maps in multiple projections into a single Geographic Information System (GIS) without visual errors, through constructing a discrete GIS database that is managed by a Relational Data Base Management System (RDBMS). Unlike in a traditional large GIS database, the data are "physically discrete but logically continuous." In a new discrete GIS database, every map keeps its individuality without a relationship to any other map, and the relationships among the maps are centrally managed by a RDBMS. A study site was chosen at the boundary of the state of Indiana …


The Effect Of Divalent Cations On The Prophenoloxidase Enzyme Cascade Activity In The Freshwater Crayfish Cambarus Latimanus, Hans Skailand Eikaas Dec 1999

The Effect Of Divalent Cations On The Prophenoloxidase Enzyme Cascade Activity In The Freshwater Crayfish Cambarus Latimanus, Hans Skailand Eikaas

Theses and Dissertations

The effect of divalent cations such as cadmium, calcium, copper, lead and magnesium upon the prophenoloxidase system (proPO) was studied in hemocytes of the crayfish Cambarus latimanus. It was demonstrated that cadmium, calcium, copper and lead increased proPO activity significantly, whereas magnesium had no statistically significant effect on the system. Also, the molecular weight of the proPO enzyme was estimated using SDS-PAGE and found to be approximately 76 kDa.


Calibration, Installation Techniques, And Initial Measurements For Vertical Resistivity Probes Used In Hydrogeologic Investigations, Jeffrey Mark Groncki Dec 1999

Calibration, Installation Techniques, And Initial Measurements For Vertical Resistivity Probes Used In Hydrogeologic Investigations, Jeffrey Mark Groncki

Masters Theses

Vertical Resistivity Probes (VRPs) are being increasingly used in a variety of applications where detailed vertical resistivity information in both the vadose and saturated zones is needed. All the different possible array types and spacings must be calibrated for the effect of the 2" (outer diameter) insulating PVC cylinder on which the electrodes are mounted. Apparent resistivities must be corrected by calibration factors. Varying the installation parameters greatly influences the measured apparent resistivity because of the disturbed annulus and the composition of the backfill materials. Bentonite slurry is necessary for the installations to keep the electrodes in good contact with …


Reciprocal Transplantation Of The Desert Soil Crust: Can It Be Done?, Christina D. Cole Dec 1999

Reciprocal Transplantation Of The Desert Soil Crust: Can It Be Done?, Christina D. Cole

UNLV Theses, Dissertations, Professional Papers, and Capstones

A 100 meter X 100 meter study site was chosen at White Rock Springs in Red Rock Canyon National Conservation Area, Nevada. To examine Syntrichia caninervis, a desert crustal moss, reciprocal transplantations (20 mm and 40 mm diameter cores) were performed between shaded to shaded, exposed to exposed, and shaded to exposed microsites to determine if it was possible to transplant the study organism with reasonable survivorship. Transplants were inspected following rain events for percent hydration, number of dead stems, and change in percent cover. Data indicated that there was a low mortality rate of S. caninervis stems, and few …


Systemic Environmental Analysis Of The Legal Mechanisms For Controlling Air Pollution In The Las Vegas Valley, Richard Little Dec 1999

Systemic Environmental Analysis Of The Legal Mechanisms For Controlling Air Pollution In The Las Vegas Valley, Richard Little

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study examines the air pollution control structure for the Las Vegas Valley. A System Dynamics computer model was created that represents the structure of the real world system for controlling air pollution, in order to examine how the current air pollution control system might behave in the future.


Resource Law Notes Newsletter, No. 47, Fall Issue, 1999, University Of Colorado Boulder. Natural Resources Law Center Oct 1999

Resource Law Notes Newsletter, No. 47, Fall Issue, 1999, University Of Colorado Boulder. Natural Resources Law Center

Resource Law Notes: The Newsletter of the Natural Resources Law Center (1984-2002)

No abstract provided.


Pollution Prevention: Factors Behind Toxic Release Reduction In The U.S. Paper Industry, John P. Tiefenbacher, William D. Solecki Sep 1999

Pollution Prevention: Factors Behind Toxic Release Reduction In The U.S. Paper Industry, John P. Tiefenbacher, William D. Solecki

RISK: Health, Safety & Environment (1990-2002)

Drs. Tiefenbacher and Solecki analyze the factors associated with, and influential in, the reduction of toxic releases in the U.S. paper industry.


The Effects Of Phosphorus Enrichment On The Dominant Phytoplankton Communities Of Chaney Lake, Kathy Tehrani Aug 1999

The Effects Of Phosphorus Enrichment On The Dominant Phytoplankton Communities Of Chaney Lake, Kathy Tehrani

Masters Theses & Specialist Projects

Chaney Lake is a temporary karst wetland located in southern Warren County, Kentucky. Because of an impermeable chert layer between the surface and the porous limestone, Chaney Lake fills with water over the winter and spring and then gradually drains over the summer. Three experiments were conducted over the course of the 1998 flooding season to assess the effects of phosphorus addition on the phytoplankton community in Chaney Lake. Ten plastic-sided mesocosms were constructed and placed in the marsh area of the wetland at three different periods: early spring, early summer, and late summer. Phosphorus in the form of K2HPO4 …


The Arab Republic Of Egypt: Initial National Communication On Climate Change, Egyptian Environmental Affairs Agency Jun 1999

The Arab Republic Of Egypt: Initial National Communication On Climate Change, Egyptian Environmental Affairs Agency

Egypt & Libya

Although Egypt’s contribution to Green House Gases is relatively minimal, yet given Egypt’s growing population, its limited fertile land, and its large area of desert, and the concentration of its economic activities in the coastal zones, the potential social and economic impact of climate change could be devastating for the country’s future.


Cadmium, Chromium And Lead In Environmental Samples : Speciation And Determination, Hsing-Hui Yu May 1999

Cadmium, Chromium And Lead In Environmental Samples : Speciation And Determination, Hsing-Hui Yu

Dissertations

Heavy metals are important contaminants in many environmental media. This work focuses on the improvement of current methods for water and sediment analysis for three metals, cadmium, chromium and lead. Batch ion exchange was used for water speciation and a microwave assisted sequential extraction scheme was developed for sediment characterization. The developed methods were applied to a group of environmental samples.

The exchangeable species of these metals in water were preconcentrated on ion exchange resins. These include the bioavailable free ions and weakly complexed ions. Metals sorbed on particles and strongly complexed ions, less bioavailable, were eliminated. The method was …


An Examination Of The Self-Perceptions Of The Physical Environment And Psychological Health Of Latina Women Living In The St. Columbia Neighborhood Of Newark, New Jersey, Veronica Maria Maya May 1999

An Examination Of The Self-Perceptions Of The Physical Environment And Psychological Health Of Latina Women Living In The St. Columbia Neighborhood Of Newark, New Jersey, Veronica Maria Maya

Theses

A correlation between perceptions of environmental quality and psychological health has been established in a sample of Latina women. Three psychological scales exist to measure psychological constructs such as learned helplessness, hopelessness, and selfesteem. These three scales have been used in conjunction with an environmental survey designed to capture the perceptions of the sample to their physical environment.

The mean of scores for each psychological construct in the Latina sample were compared to the mean of scores for these constructs in independent samples of oncology, hemodialysis, and spinal cord injured patients being treated for depression. This comparison yields the following …


History Of Oxygenated Gasoline Use In New Jersey 1992-1998, Jean Niebuhr Borne May 1999

History Of Oxygenated Gasoline Use In New Jersey 1992-1998, Jean Niebuhr Borne

Theses

New Jersey has been required to use oxygenated gasoline from November 1 to March 30 since 1992 in order to reduce carbon monoxide from vehicles. This requirement was part of the Clean Air Act Amendments of 1990. For the past six winters, New Jersey has utilized gasoline with methyl butyl tertiary ether, MTBE, as the oxygenate. In New Jersey, and in many states across the country, health complaints were reported after oxygenated fuel started flowing from gas pumps.

Oxybusters is a grassroots organization dedicated to the removal of oxygenated gasoline off the market. The group has pressured Governor Whitman to …


Unlv Residence Hall Recycling & Reuse Program For Move-In And Move-Out, Angela Michelson May 1999

Unlv Residence Hall Recycling & Reuse Program For Move-In And Move-Out, Angela Michelson

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this thesis was to develop a program for the UNLV Residence Hall Recycling & Reuse Program for Move-In and Move-Out that would collect unwanted and unneeded materials from the residents and put them to use. Move-In collected cardboard boxes for recycling while Move-Out collected usable items such as shoes, clothes, food, bedding, and school supplies for resale. In order to have a good collection turnout, a combination of advertising and resident and staff education was conducted. Letters were sent to Resident Assistants (RA’s) and Complex Coordinators and posters and other advertisements were placed in high traffic areas …


Center For Sustainable Agricultural Systems Newsletter, May/June 1999 May 1999

Center For Sustainable Agricultural Systems Newsletter, May/June 1999

Center for Sustainable Agricultural Systems: Newsletter (1993–2000)

Contents:

The Farmer and the Dean

University Role in Biotechnology: Who Owns Genes and Diversity?

CSAS Volume 9 Discusses Watersheds

SARE Appoints Paula Ford North Central PDP

Coordinator Policy Project Identifies Retention of Farms and Farmland as Top Priorities

Olson Heads to Kentucky

Organic Grain Farming Workshops

Two Alternative Agriculture Conferences in Midwest


Molecular Characterization Of Soil Ammonia-Oxidizing Bacteria Based On The Genes Encoding Ammonia Monooxygenase, Jose Javier Alzerreca May 1999

Molecular Characterization Of Soil Ammonia-Oxidizing Bacteria Based On The Genes Encoding Ammonia Monooxygenase, Jose Javier Alzerreca

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ammonia-oxidizing bacteria (AOB) are chemolithotrophs that oxidize ammonia/ammonium to nitrite in a two-step process to obtain energy for survival. AOB are difficult to isolate from the environment and iso lated strains may not represent the diversity in soil. A genetic database and molecular tools were developed based on the ammonia monooxygenase (AMO) encoding genes that can be used to assess the diversity of AOB that exist in soil and aquatic environments without the isolation of pure cultures. The amo genes have excellent potential as molecular markers; since AMO is only found in the AOB and is essential for their metabolism, …


Ultraviolet-B Radiation: Effects On Pollen Of 34 Taxa, And Inheritance Patterns And Carryover Of Radiation Response In Arabidopsis, Javad Torabinejad May 1999

Ultraviolet-B Radiation: Effects On Pollen Of 34 Taxa, And Inheritance Patterns And Carryover Of Radiation Response In Arabidopsis, Javad Torabinejad

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Although considerable research has addressed effects of elevated ultraviolet-B (UV-8) radiation on vegetative plant structures and processes, the reproductive biology and patterns of inheritance of UV-B tolerance have received much less attention. I examined the effects of UV-B radiation on pollen of 34 taxa. I also addressed questions concerning the patterns of inheritance of UV-B tolerance in Arabidopsis thaliana and examined potential cumulative carryover effects of UV-B exposure through multiple generations of this species.

In the first study, a significant reduction in pollen germination occurred in only five species, but pollen tube growth in more than half of the species …


Spring 1999, Nsu Oceanographic Center Apr 1999

Spring 1999, Nsu Oceanographic Center

Currents

No abstract provided.


Golf Courses In Southern Nevada Will Significantly Impact The Water Management Efforts By Using Recycled Water Rather Than Potable Water To Irrigate Their Turf, Sean D. Ainsworth Apr 1999

Golf Courses In Southern Nevada Will Significantly Impact The Water Management Efforts By Using Recycled Water Rather Than Potable Water To Irrigate Their Turf, Sean D. Ainsworth

UNLV Theses, Dissertations, Professional Papers, and Capstones

As the number of people continually move to the Las Vegas Valley and take up residence, the possibility of "running out of water" can become a reality. Having large water users (i.e. golf courses) irrigate their turf with recycled water, they will significantly impact the water management efforts in the Las Vegas Valley. When each course is irrigating their turf with recycled water, this will help ease the drinking water demand in the valley, especially during the peak demand season (summer).


Rio Natural Gas, The Alternative Fuel Of The Future, Peter Garner Apr 1999

Rio Natural Gas, The Alternative Fuel Of The Future, Peter Garner

UNLV Theses, Dissertations, Professional Papers, and Capstones

Automobile exhaust is a major contributor of harmful air pollutants. Exhaust emissions include water (H2O), carbon dioxide (CO2), carbon monoxide (CO), nitrous oxides (NOX), sulfur oxides (SOX), hydrocarbons (HC), and particulate matter (PM), and of these the four major air pollutants are CO, HC, NOX, and PM. Particulate matter is predominantly emitted from diesel fuel burning vehicles. In order to aid in reduction of air pollution, and reduce dependence on foreign oil imports, federal legislation has been enacted. The two prominent acts are the National Energy Security Act in 1992, which mandates use of alternative fuels, and the Clean Air …


Environmental Risk And The Traditional Sector Approach: Market Efficiency At The Core Of Environmental Law, John Martin Gillroy Mar 1999

Environmental Risk And The Traditional Sector Approach: Market Efficiency At The Core Of Environmental Law, John Martin Gillroy

RISK: Health, Safety & Environment (1990-2002)

Professor Gillroy provides an in-depth discussion on the evolution of environmental law and the proposition that market efficiency has been, and still is, at its core.


Santa Clara Magazine, Volume 40 Number 4, March 1999, Santa Clara University Mar 1999

Santa Clara Magazine, Volume 40 Number 4, March 1999, Santa Clara University

Santa Clara Magazine

8 - ENGAGING HEARTS AND MINDS By President Paul L. Locatelli, S.J. '60. Does an SCU education help students become more humane, more able to engage with life? Do students work to transform the world? Does a Santa Clara education fire both their hearts and minds?

12 - TREASURE ISLANDS By Sam Scott '96. The Women Broncos soccer team soars to the 1998 NCAA Finals. With a roster packed with talent, players and coach hold high hopes for 1999·

16 - SOCKING IT TO THEM By Connie Hinckley. Six SCU faculty emeriti apply intellectual curiosity and passion to their retirement …


Field Station Under Threat, Paul Faulstich Mar 1999

Field Station Under Threat, Paul Faulstich

Pitzer Faculty Publications and Research

As reported in the last issue of The Other Side, The Bernard Biological Field Station of the Colleges is slated to be the site of the Keck Graduate Institute, the newest (but yet unbuilt) addition to the Claremont Consortium. With Pitzer casting the sole dissenting vote, the Claremont Colleges approved construction of the Keck Institute on eleven acres of the 85 acre Field Station.