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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.
11

The Use of Community-Based Conservation in Natural Resource Management: Case Studies from The Nature Conservancy of Virginia

Babylon, Ruth G. 20 November 2003 (has links)
In March 2002, The Nature Conservancy purchased a 9,000-acre tract of land on and near Warm Springs Mountain in Bath County, Virginia. The purpose of this paper is to examine community-based conservation strategies utilized by The Nature Conservancy in two well-established Virginia reserves to determine the effectiveness of those strategies in the protection of Warm Springs Mountain. The Conservancy's previous work on Virginia's Eastern Shore and in the Clinch Valley of southwest Virginia reveals the organization's transition from a strategy of mere land acquisition to the use of community-based conservation in an effort to involve local citizens and promote a proper balance between economics and the environment. The community-based conservation model developed by TNC on the Eastern Shore and utilized further in the Clinch Valley works well for ecoregions that fit a particular typology. The paper discusses the differences between that typology and the factors affecting the protection of Warm Springs Mountain. In addition, the paper outlines the lessons TNC learned from both positive and negative experiences in the two earlier preserves and proposes how these lessons can be applied to the Warm Springs Mountain Preserve. / Master of Urban and Regional Planning
12

An Ecotoxicological Recovery Assessment of the Clinch River Following Coal Industry-related Disturbances in Carbo, Virginia (USA): 1967-2002

Hull, Matthew S. 06 January 2003 (has links)
American Electric Power's (AEP) coal-fired Clinch River Plant, a power-generating facility in Carbo, Russell County, Virginia (USA), has impaired Clinch River biota through toxic spills in 1967 and 1970, and effluent copper (Cu) concentrations that were reported to have exceeded water quality criteria from 1985-1989. These impacts have provided impetus for many research projects addressing the absence of bivalves, including federally protected species of native mussels (Unionoidea), from sites influenced by CRP effluent. Modifications in CRP effluent during 1987 and 1993 drastically reduced Cu levels and warranted the present study, which assessed long-term biological recovery in Clinch River biota near the CRP. In 2000-2001, surveys of benthic macroinvertebrate communities and instantaneous measures of effluent toxicity did not foretell significant reductions in survivorship and growth of field-caged Asian clams (Corbicula fluminea) at sites downstream of the CRP. More importantly, these results indicated renewed toxicity in CRP effluent. Additional transplant studies using two enclosure types were conducted to isolate effects attributable to CRP effluent from the potentially confounding effects of substrate variability among study sites. While it was found that mean growth of clams was greatest in the enclosure that minimized substrate variability (p=0.0157), both enclosure types clearly distinguished significant impairment of survivorship and growth at sites downstream of the CRP discharge, and strengthened the association between impairment and CRP effluent. An intensive field investigation was undertaken to determine whether impairment observed in transplant studies extended to resident bivalves. During 2001-2002, densities and age structures of C. fluminea and distributions of mussels suggested that impairment indeed extended to resident bivalves for a distance of 0.5 to 0.6 km downstream of the CRP discharge. Impairment of bivalves was less evident below (1) a fly ash landfill and (2) coal mining activities and low-volume leachate from a bottom ash settling pond. With respect to long-term recovery, modifications in CRP effluent treatment have reduced Cu concentrations from an average of 436 mg/L in 1985-1989 to 13 mg/L in 1991-2002. Subsequently, Cu body burdens of Asian clams (Corbicula fluminea) transplanted within CRP influence have decreased from 442% of levels accumulated at reference sites in 1986, to 163% of these levels in 2002. The reduction in effluent Cu largely explains recovery of most benthic macroinvertebrate community parameters (e.g., richness, diversity) at influenced sites from levels that were typically less than 70% of reference levels, to levels that frequently range from 80 to greater than 100% of reference levels. Nevertheless, bivalves remain impaired downstream of the CRP; survivorship and growth of C. fluminea transplanted to CRP-influenced sites have typically been less than 40 and 20% of reference values, respectively. Furthermore, C. fluminea has seldom been encountered within CRP influence for nearly two decades. Likewise, native mussels remain absent within CRP influence, but recent surveys suggest their downstream distributions are more proximate to the CRP discharge than has been reported previously. A preliminary assessment of factors potentially contributing to toxicity revealed that (1) water reclaimed from settling basins for discharge with CRP effluent significantly impaired fecundity of ceriodaphnids at concentrations of 50%, (2) LC50 values for industrial treatment chemicals were misrepresented on Material Safety Data Sheets and consequently, were subject to misapplication by operators, (3) Cu concentrations of 96 mg/L significantly impaired growth of Asian clams in artificial stream testing, and (4) effluent Al exceeded acute and chronic water quality criteria, suggesting this ion should receive further consideration in future studies. / Master of Science
13

A cost-effectiveness analysis of alternative regulatory approaches under the Endangered Species Act of 1973

Taylor, Michael A. January 1993 (has links)
The rate of extinction of plant and animal species has accelerated at an alarming rate throughout the 20th century. This depletion has resulted in greater legislative control over wildlife within the United States, and the eventual passage, in 1973, of the Endangered Species Act (ESA). The ESA establishes regulations designed to protect species which are threatened with extinction. The ESA has evolved out of past legal statutes and jurisprudence concerning the management and protection of wildlife, but the ESA has created controversy since inception. The latest criticisms concern its lack of success in meeting stated policy goals of preserving species richness and recovering listed species. As a result, a new movement has developed which seeks to change the traditional species-by-species approach of the ESA to an approach which concentrates on entire ecosystems. Ecosystem approach proponents sight various advantages, one of which is cost-effectiveness. This thesis analyzes the development of wildlife protection within the United States, and the Endangered Species Act in particular. The purpose of this analysis is to examine both the legislative powers granted for wildlife protection, and the feasibility of the ESA to encompass ecosystem protection. Modifications to the ESA are proposed. The Clinch River Valley, in Southwest Virginia and Northeast Tennessee, is used as a case study for a cost-effectiveness analysis of an ecosystem approach and species-by-species approach. Costs generated through Fish and Wildlife Service recovery plans are used in conjunction with generated ecosystem plan recovery costs. The results of the cost-effectiveness analysis show that an ecosystem approach is more cost-effective in meeting the recovery goals within the 0inch River Valley. The ESA can be modified to incorporate an ecosystem approach. Such modification can protect species richness and allow for a priority ranking system for protection. / M.S.
14

Effects of sewage treatment plant effluents on mollusks and fish of the Clinch River in Tazewell County, Virginia

Goudreau, Stephanie E. 22 June 2010 (has links)
The Clinch River is renown for its rich mollusk and fish assemblages, including many endemic species. New sewage treatment plants (STP's) have recently been constructed along the Clinch River in Virginia, raising concern because of the disappearance of mollusks below existing STP's. Field and laboratory studies were conducted to determine mollusk and fish distribution in proximity to two STP's in Tazewell County, and the tolerance of two mollusk species to mono chloramine and unionized ammonia, the major toxicants in domestic STP effiuent. River reaches up to 3.75 km downstream of the STP outfalls at Tazewell and Richlands were depauperate of mussels. Tolerance to effluent seemed to vary among snails, sphaeriid clams, and the Asiatic clam <i>Corbicula flumineaK</i>. After an initial toxic zone below the Tazewell outfall, abundance of fish appeared to increase by 0.45 km below the outfall. The effluent at Richlands eliminated intolerant species, and more tolerant species were present as far as 0.45 km below the outfall. Laboratory bioassays with glochidia of <i>Villosa nebulosa</i> resulted in 24-h EC₅₀ and LC₅₀ values of 0.042 and 0.084 mg/L monochloramine, respectively, and 24-h EC₅₀ and LC₅₀values of 0.237 and 0.284 mg/L unionized ammonia, respectively. Glochidia rank among the most sensitive invertebrates in their tolerance to these toxicants. The snail <i>Pleurocera unciale unciale</i> was moderately sensitive, with 96-h LC₅₀ values of 0.252 mg/L mono chloramine and 0.742 mg/L unionized ammonia. Comparison of monochloramine and unionized ammonia concentrations monitored at 0.10 km below the outfalls indicated that mono chloramine was the major toxicant likely affecting fauna. / Master of Science
15

Assessment of Mussel Declines in the Clinch and North Fork Holston Rivers Using Histological Evaluations of Vital Organs

Rogers, Jennifer J. 31 August 2015 (has links)
The Clinch River (CR) and North Fork Holston River (NFHR) contain some of the most diverse freshwater mussel assemblages in the United States; however, both rivers are experiencing declines in mussel populations. The first component of this study used histological evaluations and water quality data to determine whether mussels were negatively impacted in the CR zone of decline (ZD) and to inform future management of freshwater mussels in the river. In the 91 kilometer (km) section from Carbo, Virginia (CRKM 431) downstream to Speers Ferry, Virginia (CRKM 340), referred to as the ZD, mussel density decreased >90% from 1979 to 2014 at key sites such as Semones Island (CRKM 378.3) and Pendleton Island (CRKM 364.2). Laboratory propagated mussels were placed in cages in the river for one year from June 2012 to May 2013 at four sites within the ZD and four sites in reaches where mussel populations remain stable or are increasing, a zone of stability (ZS). The survival, growth and histological results indicated that there are continuing impacts to mussels in the ZD. Research investigating impacts to the ZD and methods to improve water quality in this zone are needed. The laboratory component of this study examined sublethal effects of potassium (K⁺), chloride (Cl⁻), and un-ionized ammonia (NH₃-N) on mussel tissues at concentrations relevant to those found in the NFHR. Historical industrial activities at Saltville, Virginia, as well as continued pollution of the NFHR from chemical waste ponds at this location, are believed to be significant contributors to mussel declines. Contaminant seepages from the waste ponds that include Cl⁻, K⁺, and NH₃-N have been shown to be toxic to adult and juvenile mussels. A three-month laboratory study was conducted to assess impacts to organ tissues (gills, digestive glands, kidneys, and gonads) of adult Villosa iris exposed to environmentally relevant concentrations of K⁻ (4 and 8 mg/L), Cl⁻ (230 and 705 mg/L), and NH₃-N (0.014 and 0.15 mg/L) using histological evaluations. No detectable differences were observed among the histological endpoints from mussels held in treatments and control (p>0.05). The study design was modified and repeated using increased concentrations of K⁺ (8, 16, and 32 mg/L) and Cl⁻ (705, 1410, and 2820 mg/L) for a two-month exposure period. Due to issues with maintaining NH3-N in mussel holding chambers, the second study did not the second study did not include NH₃-N exposures. Control mussels in both studies had a higher abundance of lipofuscin in kidneys and degraded cytoplasm in the digestive gland diverticula compared to baseline mussels, indicating that captivity influenced mussel tissues. Future studies are needed to more thoroughly address these captivity effects. Both survival and histological data in the second test showed a significant negative effect of the increased concentrations of Cl⁻ and K⁻, which were representative of those found at some sites in the NFHR downstream of Saltville, Virginia. / Master of Science
16

Propagation of Juvenile Freshwater Mussels (Bivalvia: Unionidae) and Assessment of Habitat Suitability for Restoration of Mussels in the Clinch River, Virginia

Zimmerman, Lora Leigh 07 April 2003 (has links)
Freshwater mussel propagation techniques were tested at the Virginia Department of Game and Inland Fisheries Aquatic Wildlife Conservation Center through a series of three experiments. Experiment 1 tested the suitability of a pond and raceway for rearing juvenile oystermussels (Epioblasma capsaeformis) and wavyrayed lampmussel (Lampsilis fasciola). This experiment was prematurely terminated due to predation on mussels by fathead minnows (Pimephales promelas). Experiment 2 evaluated growth and survival of juvenile rainbow mussels in outdoor troughs and indoor aquaria. There was no significant difference in survival or growth between the two systems. Experiment 3 used troughs similar to those in Experiment 2 to rear E. capsaeformis and L. fasciola under two silt regimes. Survival for Experiment 3 was significantly greater for L. fasciola. The comparison between silt regimes indicated that individuals in the high-silt treatment had better survival than those in the low-silt treatment. The difference between these 2 treatments may be a reflection of increased escapement in the low-silt treatment, which may have resulted from more frequent disturbance during sampling. Growth of L. fasciola was significantly greater than E. capsaeformis, and was greater in the low-silt treatment. A habitat survey of the Clinch River, Virginia was conducted from Blackford, Clinch River Kilometer (CRK) 478 to the Tennessee border, CRK 325. Physical characteristics identified in the survey were combined with water quality and impact source data to develop a habitat suitability index for freshwater mussels within this study reach. Model parameters were indexed and weighted to give a final suitability ranking. Habitat units having the highest overall ranking included: Nash Ford (CRK 449), Artrip (CRK 442), several riffles and runs below Carterton (CRK 417), upstream of Mill Island (CRK 389.5), and Pendleton Island (CRK 365), and Speers Ferry (CRK 333-325). Potential locations for habitat restoration projects and additional monitoring were also identified. / Master of Science
17

Unterraum-CG-Techniken zur Bearbeitung von Kontaktproblemen

Unger, Roman 28 February 2007 (has links) (PDF)
Der Gegenstand dieser Arbeit ist die Untersuchung spezieller Lösungsmethoden zum Problem des Kontaktes eines elastischen Körpers mit einem festen Hindernis sowie des Kontaktes zweier elastischer Körper miteinander. Grundlage der Betrachtungen ist dabei ein Lösungsverfahren, das auf Unterraum-CG-Techniken beruht. Die zu Grunde liegende partielle Differentialgleichung zur Modellierung der Verformung eines elastischen Körpers ist die Lame-Gleichung. Aufbauend auf dieser Gleichung wird das Problem des Kontaktes in einer neuen Formulierung, die auch große Verformungen zuläßt, betrachtet. Um diese Probleme mit Hilfe der Finiten-Elemente-Methode numerisch lösen zu können, erfolgt die Betrachtung der üblichen Variationsformulierung mit Hilfe von Variationsungleichungen sowie die Angabe einer alternativen Formulierung, die auf einer Variationsgleichung beruht. Zur Konstruktion eines effektiven Lösungsalgorithmus werden die Problematiken der a-posteriori Fehlerschätzung, Voraussetzungen an Vernetzungen sowie moderner Lösungsmethoden zum Auflösen des Finiten-Elemente-Gleichungssystems betrachtet. Um die aus dem Kontaktproblem resultierenden Restriktionen zu erfüllen, wird die Klasse der Unterraum-CG-Verfahren einführend betrachtet und es wird die Anpassung dieser Verfahren auf die betrachteten Probleme vorgestellt. Die für derartige Lösungsmethoden verwendeten Projektoren werden formuliert und es werden verschiedene Formulierungen dieser Projektoren in Bezug auf Effektivität der Implementierung sowie Speicheraufwand miteinander verglichen. Es wird auf einige verschiedene Möglichkeiten der Beschreibung von Hindernissen sowie des Kontaktproblems zweier elastischer Körper miteinander eingegangen und es werden Referenzimplementierungen zu diesen Problemen angegeben. Zu den implementierten Projektoren werden Beispielrechnungen am Ende der jeweiligen Abschnitte vorgestellt sowie die Rechenzeiten und Konvergenzverhalten restringierter und unrestringierter Elastizitätsprobleme verglichen. Es zeigt sich dabei der Vorteil der entwickelten Verfahren in einem vergleichbaren numerischen Aufwand zwischen restringierten und unrestringierten Problemen bei einer übersichtlichen Implementierbarkeit und guter Stabilität. Die Problemklasse von Restriktionen im Inneren des betrachteten Gebietes wird anhand des Clinch-Problems formuliert, und die zur Lösung derartiger Probleme verwendeten Projektoren betrachtet. Die Referenzimplementierung aller vorgestellen Algorithmen und Projektoren erfolgt dabei in einem adaptiven 2D-FEM-Programm, welches innerhalb des DFG-Sonderforschungsbereichs 393 "Parallele Numerische Simulation für Physik und Kontinuumsmechanik" entstanden ist.
18

Habitat models for predicting the occurrence of blotchside logperch (Percina burtoni) and tangerine darters (P. aurantiaca) in the North Fork Holston River and Little River, Virginia

Leftwich, Kevin Ned 23 June 2009 (has links)
Basin-wide visual estimation techniques developed in the Pacific Northwest for small streams were modified to survey about 180 river kilometers (rkm) of the North Fork Holston River and about 16 rkm of lower Little River (Clinch River tributary) in southwestern Virginia during the summer of 1992 and 1993, respectively. Presence-absence models were developed, using stepwise logistic regressions, from habitat characteristics measured on a scale ranging from large-scale (geographic location) to local-scale (habitat-unit characteristics) for blotchside logperch (<i>Percina burtoni</i>) and tangerine darter (<i>P. aurantiaca</i>) in the North Fork Holston River. Transferability of models, developed for both species in the North Fork Holston River, to Little River were tested by comparing the models' predictions with the data collected during the Little River survey. / Master of Science
19

”Båtnitar” : Analys och konservering av järnnitar från Birkas garnison

Johansson, Harald January 2006 (has links)
<p>The purpose of this paper is to analyse and discuss clinch-nails found at an excavation at terrace II in the Garrison of Birka, on the island of Björkö in Sweden. This type of clinch-nails is common in Viking age Sweden and is usually interpreted as coming from boats. The study will try to show that these types of nails could have been used in several kinds of wooden constructions. It will also show how the nails were made and what kinds of tools were used by the Viking smiths. The study has shown that this type of nails were used in several different types of wooden constructions such as boats, sleds, cart bodies, coffins, Birka's ramparts and buildings. Nothing confirms the use of rivets in Viking age buildings but the material from terrace II probably contains clinch-nails from the other categories. The largest portion of the clinch-nails comes from disused boats and from the ramparts surrounding Birka's hill fort Borg. The tools for making nails have not been found in the Birka Garrison.</p>
20

”Båtnitar” : Analys och konservering av järnnitar från Birkas garnison

Johansson, Harald January 2006 (has links)
The purpose of this paper is to analyse and discuss clinch-nails found at an excavation at terrace II in the Garrison of Birka, on the island of Björkö in Sweden. This type of clinch-nails is common in Viking age Sweden and is usually interpreted as coming from boats. The study will try to show that these types of nails could have been used in several kinds of wooden constructions. It will also show how the nails were made and what kinds of tools were used by the Viking smiths. The study has shown that this type of nails were used in several different types of wooden constructions such as boats, sleds, cart bodies, coffins, Birka's ramparts and buildings. Nothing confirms the use of rivets in Viking age buildings but the material from terrace II probably contains clinch-nails from the other categories. The largest portion of the clinch-nails comes from disused boats and from the ramparts surrounding Birka's hill fort Borg. The tools for making nails have not been found in the Birka Garrison.

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