• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 242
  • 143
  • 18
  • 9
  • 6
  • 4
  • 4
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 612
  • 612
  • 139
  • 119
  • 114
  • 98
  • 92
  • 78
  • 76
  • 76
  • 71
  • 62
  • 58
  • 54
  • 52
  • 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.
321

Biomarkers in perch (Perca fluviatilis) used in environmental monitoring of the Stockholm recipient and background areas in the Baltic Sea

Hansson, Tomas January 2008 (has links)
This thesis reports the results of biomarker measurements in three environmental monitoring projects. In the first project, which was part of the Swedish national environmental monitoring, biomarkers were measured annually in female perch (Perca fluviatilis) in two background areas in the Baltic Sea during 1988–2000, resulting in a unique 13-year series of measurements. The most important results were a strong decreasing temporal trend in the gonadosomatic index (GSI) and a strong increasing temporal trend in the hepatic ethoxyresorufin O-deethylase (EROD) activity in the Baltic Proper. In the second project, biomarkers and concentrations of classic pollutants were measured in female perch in the Stockholm recipient 1999–2001. This was the first time a large city was investigated as a point source of pollution, and the gradient was longer and included more stations than customary. Severe pollution conditions in central Stockholm were indicated by the poor health status of the perch: retarded growth, decreased frequency of sexually mature females, low GSI, disturbed visceral fat metabolism, increased hepatic EROD activity, decreased muscle acetylcholinesterase activity, increased frequency of hepatic DNA adducts, and a high concentration of biliary 1-pyrenol. Muscle ΣDDT and ΣPCB were measured as pollution indicators and were 10–28 respectively 12–35 times higher than the background levels in perch from the Baltic Proper. In the Stockholm archipelago two superimposed gradients were found. Whereas the response of several biomarkers consistently decreased with increasing distance from central Stockholm, the response of others first decreased from Stockholm to the middle archipelago and then increased to the open Baltic Sea. The latter biomarkers included the frequency of sexually mature females, GSI, hepatic EROD activity, and hepatic DNA adducts. In the third project, potential toxicity from munitions on the seafloor, at a dumpsite in the Stockholm archipelago, was analysed by the nanoinjection of sediment extracts into newly fertilised rainbow trout (Oncorhynchus mykiss) eggs, followed by the measurement of biomarkers in the developing larvae. No biological effects of the dumped munitions were found. The same stations in the Stockholm archipelago as in the second project were investigated as a positive control. The results of the three projects agreed well, which demonstrated the continuous pollution of the Baltic Sea and the severe pollution conditions and adverse biological effects in central Stockholm. Further investigations are urgently needed to identify which pollutants or other factors are causing the observed biological effects, both in the background areas in the Baltic Sea and in the Stockholm recipient.
322

Verification of dose limitation of the general public and determination of lead equivalence of x-ray rooms at Karolinska University Hospital Huddinge

Tamras, Dina January 2006 (has links)
A variety of radiation sources exist at the Department of Radiology and the Department of Nuclear Medicine at Karolinska University Hospital Huddinge. Radiation sources can also be found in areas outside of these departments due to the wide use of mobile xray machines and fluoroscopic c-arm equipment and also due to the movement of patients that have received diagnostic or therapeutic doses of radionuclides. In a proposal for a new legislation from the Swedish Radiation Protection Authority (SSI), which was later issued as legislation SSI FS 2005:6, the effective doses of the general public from a practice using ionising radiation need to be kept below stated limit of 0.1 mSv/year. This project was performed to verify the dose limit for individuals of the general public in the above mentioned practices. Long-term measurements with TL-dosimeters were utilised to carry out the environmental monitoring of the areas throughout the Departments of Radiology and Nuclear Medicine. To assess the contribution of ionising radiation from rooms housing mobile fluoroscopic c-arm equipment to surrounding areas, a tissue equivalent phantom of size (30×30×20 cm3) was employed to simulate a patient and the scattered radiation was monitored by using area monitors, such as portable proportional counters. The annual effective doses were calculated in terms of personal dose equivalent as well as ambient dose equivalent monitored using TL-dosimeters and area monitors, respectively. The stated limit of 0.1 mSv/year to the general public was verified by risk analysis. An attempt to create a method for determining the amount of radiation shielding in terms of lead equivalence in walls, doors, protective glasses of manoeuvre rooms and cupboards of diagnostic x-ray labs was also performed using a radiation point source of 99mTc and a NaI scintillation detector. Depending on the accuracy in the measurements the amount of lead deviated slightly from the expected 2 mm value based on the former legislation SSI FS 1991:1.
323

More Water, Less Grass? : An assessment of resource degradation and stakeholders’ perceptions of environmental change in Ombuga Grassland, Northern Namibia

Klintenberg, Patrik January 2007 (has links)
The objectives of this thesis are to assess: to what degree have natural resources deteriorated in a grazing area in northern Namibia, how do perceptions of environmental change held by local stakeholders there, correspond to scientific assessments, and how do these relate to national estimates? Analysis of the process of developing national indicators for monitoring of land degradation concluded that specific indicators should be developed on national level, and in some instances even on local level as there are no universal causes of land degradation. According to farmers overgrazing and low rainfall since the early 1990s cause negative environmental changes in the study area, partly confirming findings from national monitoring. Results also suggest that: less grazing outside the study area, improved access, permanent water supply, and fencing of large areas, also contributed. Results show that improved water supply was the most important factor. Investigation of the influence of permanent water points on grazing resources showed that perennial grasses are replaced by less palatable annual grasses as far as 6 km from water points along a water pipeline. No significant grazing induced changes in grass composition were observed around privately owned wells. Private ownership seems to be a key factor preventing over-utilization of grazing resources around the latter. A remote sensing study using Landsat TM imagery identified bare ground, saltpans and grassland with a fair accuracy. Separation of woodland from shrubland and shrubland from grassland was less accurate using supervised classification. The results show that the soil adjusted vegetation index provides valuable information about variations of green biomass over time in semi-arid environments. However, it is suggested that satellite based investigations should be supported by thorough ground based assessment due to the influence of underlying soil in this environment.
324

Making Music Sustainable: The Case of Marketing Summer Jamband Festivals in the U.S., 2010

Cary, Melissa A. 01 August 2012 (has links)
Commercial music festivals in the United States have been growing in popularity since the 1960s. Today, many weekend-long music festivals are annual events spanning a variety of genres and often occur at the same locations each year. My research compares and contrasts how jamband music festivals are marketed as sustainable events and attempts to determine how the advertised sustainable practices are implemented and utilized at selected jamband music venues. The jamband genre of music emphasizes musical improvisation and borrows from other styles of music: rock, electronic, jazz, blues, folk, and bluegrass. In addition, any impacts these festivals have upon the local environment are evaluated. Sustainability is a topic often used as a marketing strategy when promoting summer jamband music festivals. Fans of this genre are identified with a culture that is similar to the environmentally conscious hippie culture of the 1960s and 1970s. The data for this research were obtained through field observations, interviews, surveys, and content analyses of promotional materials. It is my hypothesis that the festivals’ sustainable practices will be adopted by local communities as the festivals leave both a physical and cultural imprint upon the local landscapes, which is determined through attendee surveys and interviews with local decision makers and festival promoters. I also hypothesize that the geographic location of each will have an influence on the participation in such practices by the festival attendees, as I believe those in attendance at the High Sierra Music Festival in California will be more likely to have green lifestyles as California has been a leader in environmentally conscious innovations and attitudes, whereas other states, Illinois and Tennessee, lag behind. The data collected were mapped and analyzed to determine the effectiveness of environmental sustainability promotions and practices at the fan level as well as the local level. This research fills a gap within the geographic literature as no research exists examining the spatial relationship between music festivals and sustainability. Additionally, my research highlights that popular cultural events can be opportunities to engage in meaningful environmental education on issues such as recycling, and environmental sustainability.
325

Near-surface Atmospheric Response to Simulated Changes in Land-cover Vegetation Fraction, and Soil Moisture over Western Kentucky

Leeper, Ronnie 01 August 2009 (has links)
A series of land-use-land-cover-change (LULCC) based sensitivity experiments, including changes in vegetation type, fractional vegetation (FV), and soil moisture (SM), over Western Kentucky were conducted to investigate atmospheric response to land-use. The choice of land-use for this study was chosen in the context of Western Kentucky’s historical LULCC. For this study, vegetation types considered were grassland, forest, and bare soil with further variations in FV for grassland and forest at 25, 50, 75, and 100 % and systematic increases and decreases in volumetric SM of 0.05, 0.10, and 0.15 m3 m-3. To the author’s knowledge, this is the first assessment of its kind that incorporates these types of LULCC in a single study. In addition, typical anthropogenic land-use change often incorporates several types of LULCC. Moreover, this assessment provides a robust analysis of the impacts LULCC has on atmospheric processes over Western Kentucky. To simulate the importance of land-use on atmospheric processes, a well known meso-scale model developed by the National Center for Atmospheric Research (NCAR) and the Pennsylvania State University (PSU) MM5 coupled with an intermediately complex land surface model (LSM) Noah was used. The purpose of this research is to investigate the impact of multiple types of LULCC on planetary boundary layer (PBL) evolution, PBL stability, near surface 3D-wind fields, temperature, and moisture. Furthermore, it is anticipated that multiple types of LULCC will provide more insight into the complex nonlinear land-atmosphere interactions from atmospheric, air quality, and climatology perspectives. Modeling analysis revealed the importance of land-use on atmospheric processes. Changes in all three types of LULCC (land-cover, FV, and SM) altered the distribution of surface energy and moisture, PBL structure, 3D-wind fields, and PBL stability. In general, it was found that LULCC that enhanced (diminished) ET rates reduced (increased) sensible heat flux, atmospheric temperature and, and PBL heights below (above) control (CTRL). For instance, the conversion of land-cover from CTRL to grassland reduced 2 m temperature and PBL heights by 0.60 °C and 228 m respectively compared to CTRL due to an evaporative advantage (lower stomata resistance). Multiple types of land-use change were found to either offset or enhance overall modeled response to LULCC. A reduction in FV to 25 % over grassland diminished ET despite the evaporation advantage of grassland and increased 2 m temperature and PBL heights with respect to CTRL by 3.3 °C and 504 m. These results significantly altered horizontal and vertical wind fields, affecting moisture advection and the development of meso-scale circulations. Compared to CTRL, these differences were enhanced over drier soils, but muted over moist soils. Moreover, the impact of LULCC on atmosphere evolution was not only dependent on the type of LULCC, but also on the current state of other unaltered land surface features such as vegetation type, FV, and SM. Alterations to modeled PBL development, as a result of LULCC, can have important impacts on a region’s climatology and air quality. Simulated changes in typical PBL moisture and temperature through time can affect local and regional climatology. Depending on the type of LULCC, these alterations in climate may lead to localized cooling. In addition, it was further hypothesized that changes in PBL height can affect air quality. Given the capping inversion layer at the top of the PBL, changes in PBL heights can significantly affect air quality with lower (higher) PBL heights diminishing (enhancing) air quality. Moreover, this research prescribes the importance of considering LULCC in atmospheric assessments of climatology and air quality, including pollutant dispersion and trajectory modeling.
326

Derivation of environmental quality guidelines based on tissue burden of toxic pollutants in the green lipped mussel Perna viridis

Chu, King-hei, Vincent., 朱景熹. January 2006 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
327

Anthropogenic pollution of the Lusushwana River at Matsapha, and prospects for its control : Kingdom of Swaziland (eSwatini)

Mhlanga, Phindile January 2012 (has links)
The Lusushwana River, which is within the Maputo River Basin, forms the western boundary of Matsapha, the most industrialized town in Swaziland. Current findings suggest that the Lusushwana River is polluted by industries within the town. What is not clear is the establishment of an association between the industries and the river quality, the extent of pollution in the river, and whether the river can meet national water quality objectives. Further, literature implies that the pollution causes impacts on the riverine ecosystem, health and livelihoods of the riparian communities; and that environmental monitoring, application and enforcement of legislation are weak. There is therefore a need for a detailed investigation on the pollution of the Lusushwana River to establish whether there is an association between the industries and the river quality; and the health and livelihoods impacts on the riparian communities and riverine ecosystem, with a view to recommending intervention measures to minimize the pollution taking into account social, technical, environmental, financial and institutional factors. The research was carried out at Matsapha, Swaziland. A mixed research methodology was adopted, which enabled the researcher to employ multiple data collection methods, which in turn provided the opportunity for data triangulation and as such enhanced the study‘s rigour, validity and reliability. The research took a deductive approach, and entailed a longitudinal experimental and cross-sectional survey design. Non-probability sampling methods in the form of snowball and purposive sampling were used to select an appropriate and representative sample that can be generalized. Data were collected using technical experiments, biotic index, semi-structured open ended questionnaires, interviews, and field observations. The questionnaires were self administered to 121 riparian communities‘ households, 3 environmental monitoring agencies and 26 proprietors of companies at Matsapha. Additionally, 15 key informants were interviewed. Water and wastewater samples were taken along the Lusushwana River, and at the wastewater treatment plant and industries. Statistical analysis of the data using PASW Statistics and Microsoft Excel led to the various findings from the research. The findings confirm the claim from literature that the anthropogenic activities at Matsapha pollute the Lusushwana River. The evaluation of the Lusushwana River showed microbiological, physical, organic and inorganic pollution to be most acute; but concentrations of heavy metals such as cadmium were low. The biotic index showed the absence of macro-invertebrate species (e.g. damselflies) that are highly sensitive to oxygen-depletion pollution. The riparian communities suffer human health impacts, especially diarrhoea and skin problems, and are restricted in meeting their domestic and livelihood water needs by the quality of the Lusushwana River. This study has led to the conclusion that the Lusushwana River is polluted by the anthropogenic companies in the Matsapha industrial estate, but has revealed that there is also pollution upstream of Matsapha. The companies at Matsapha have environmental management procedures that are insufficient or ineffective; environmental awareness, education, monitoring and legislation enforcement is lacking, the riparian communities suffer health and livelihood impacts, and their complaints are not effectively addressed. Therefore the study recommends that effective monitoring, legislation enforcement, and collaboration of all stakeholders should be used to achieve effective wastewater management and to minimize pollution of the Lusushwana River and the associated impacts. The empirical findings of the study regarding the pollution of the Lusushwana River and its impacts on the riparian communities, as well as the need for effective monitoring, enforcement of legislation and collaboration of the stakeholders contribute to professional knowledge, academic research, policy and practice. Potential areas recommended for further research include studies on assessment of companies that need pre-treatment in order to minimize environmentally significant discharges into the Lusushwana River; and on how much pollution the river can receive and still meet national water quality objectives.
328

Method Development for Detecting and Characterizing Manufactured Silver Nanoparticles in Soil Pore Water Using Asymmetrical Flow Field-Flow Fractionation

Whitley, Annie R 01 January 2012 (has links)
Recent advances in nanotechnology have led to the production of materials with nanoscale dimensions (nm) and properties distinctly different from their bulk (>100 nm) counterparts. With increased use, it is inevitable that nanomaterials will accumulate in the environment and there is concern that the novel properties of nanomaterials could result in detrimental environmental and human health effects. In particular, there has been concern recently regarding the use of silver (Ag) based nanomaterials as antimicrobial agents in consumer and medical products. Current regulations dealing with the discharge of metals into the environment are based on total concentrations with no consideration for the form (e.g., ionic, nanoparticle, colloid) which can largely determine toxicity. Methods for the identification and characterization of nanoparticulates within complex matrices are lacking and the development of robust methods for this purpose are considered a high priority research area. This research focuses on the development and application of a novel method for characterizing Ag manufactured nanoparticles (MNPs) within terrestrial environments, in particular in soil pore water, with applications relevant to other metal MNPs as well. The method was then applied to understand the dynamics and behavior of Ag MNPs in soil and soil amended with sewage sludge biosolids.
329

Changing The Climate Narrative: How A Long-Term Climate Change Might Save Our Lives

Harreld, Natalie P 01 January 2014 (has links)
The goal of this paper is to offer new insights into the climate change debate by shifting away from the heated anthropologic arguments that dominate politics, media, and popular science. Instead, I choose to rely on the long-term impacts of a changing climate on our planet. The paper begins with a break down of key processes involved in short-term and long-term climate change, using the latest research. After a foundational understanding of climate sciences is established, we will discuss the failure of the climate change debate in educating the general public about the facts of a changing climate. Finally, the importance of long-term foresight in climate policy and education, and how this perspective could drastically progress the climate debate, will be discussed.
330

Bio-surveillance: detection and mitigation of disease outbreak

Lee, Mi Lim 13 January 2014 (has links)
In spite of the remarkable development of modern medical treatment and technology, the threat of pandemic diseases such as anthrax, cholera, and SARS has not disappeared. As a part of emerging healthcare decision problems, many researchers have studied how to detect and contain disease outbreaks, and our research is aligned with this trend. This thesis mainly consists of two parts: epidemic simulation modeling for effective intervention strategies and spatiotemporal monitoring for outbreak detection. We developed a stochastic epidemic simulation model of a pandemic influenza virus (H1N1) to test possible interventions within a structured population. The possible interventions — such as vaccination, antiviral treatment, household prophylaxis, school closure and social distancing — are investigated in a large number of scenarios, including delays in vaccine delivery and low and moderate efficacy of the vaccine. Since timely and accurate detection of a disease outbreak is crucial in terms of preparation for emergencies in healthcare and biosurveillance, we suggest two spatiotemporal monitoring charts, namely, the SMCUSUM and RMCUSUM charts, to detect increases in the rate or count of disease incidents. Our research includes convenient methods to approximate the control limits of the charts. An analytical control limit approximation method for the SMCUSUM chart performs well under certain conditions on the data distribution and monitoring range. Another control limit approximation method for the RMCUSUM chart provides robust performance to various monitoring range, spatial correlation structures, and data distributions without intensive modeling of the underlying process.

Page generated in 0.109 seconds