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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.
421

Projecting Future Heat-Related Mortality in the United States under Global Climate Change

Li, Ying, Kusi, Joseph 01 July 2015 (has links)
Global climate change is anticipated to raise the overall temperatures and is likely to increase future mortality attributable to heat. Predicting future health consequences of higher temperatures at the regional, national and global level based on historical temperature-mortality relationships can be challenging due in part to the uncertainties in the location-specific temperature-mortality relationship, the heat threshold, and how populations will adapt or acclimatize. This study reviews published estimates of the warm season temperature-mortality relationships around the world and explores the heterogeneity in terms of the magnitude of the relationship and the threshold. We also investigate the potential effects of adaptation and acclimatization on the estimates of excess heat-related deaths based on empirical evidence, and propose a method that can be used in future projections to address the uncertainties. This study contributes to the literature of projecting the future public health burden of heat-related effects, which provides valuable information to climate policy decision making.
422

In the Eye of the Storm: Houston after Hurricane Harvey

Tolentino-Serrano, Brandon 01 January 2019 (has links)
Situated in one of the wettest climates in America, Houston, TX has had a long history of heavy rains and unprecedented floods. Unfortunately, floods have become more common over the last few decades as climate change increases the frequency and intensity of hurricanes around the globe. To complicate matters further, Houston has quickly sprawled to accommodate over 2.5 billion people. Rapid urbanization has rendered the landscape even more susceptible to floods through excess concretization and watershed disturbance. This thesis traces the history of the Bayou City in relation to the damages caused by Hurricane Harvey. By mapping out the original neighborhoods and the current demographics of the city, I argue that low-income and minority groups have been systematically forced into higher-risk floodplains via prejudice housing practices. Furthermore, I explore the roles of the National Insurance Flood Program (NIFP) and the Federal Emergency Management Agency (FEMA) in the rebuilding of the city following Harvey, and I detail the sudden spike in unsheltered homeless people across the region. The thesis closes by critiquing projects that have been proposed for the future well-being of Houston (i.e. reservoir remediation, conveyance projects, coastal dykes, etc.). Evidently, local and outside experts across fields and organizations need to cooperate to determine the immediate and specific needs of neighborhoods and people across the city of Houston.
423

Développement d'outils analytiques innovants pour le suivi des populations de Vibrio dans les environnements aquatiques / Development of innovative analytical tools for the monitoring of Vibrio populations in aquatic environments

Silva, Elise Da 08 December 2017 (has links)
Les épisodes de mortalité massive de l’huître creuse Crassostreae gigas observés sur les côtes françaises depuis 2008 ont été associés à certaines espèces appartenant au genre bactérien Vibrio. Ces mortalités, particulièrement intenses et rapides au cœur des lagunes méditerranéennes, atteignent 80 à 100% de la production ostréicole remettant ainsi en cause la pérennité de cette activité. Une surveillance environnementale de ces bactéries apparait donc essentielle et nécessite la mise au point de méthodes d’analyse innovantes, alternatives aux techniques couramment employées, afin de permettre un suivi rapide et en temps réel des Vibrio dans les milieux aquatiques côtiers.Dans ce contexte, l’objectif de cette thèse a été de concevoir des outils analytiques de type génocapteurs pour la détection et la quantification des Vibrio dans les écosystèmes aquatiques. Dans un premier temps, un système basé sur un format d’hybridation « sandwich » reposant sur l’intercalation des acides nucléiques cibles entre une sonde capture immobilisée et une sonde signal marquée, couplé à une détection optique, a été élaboré. Après optimisation des conditions expérimentales, le test développé s’est avéré très sensible avec une limite de détection de 5 ng.µL-1 d’acides nucléiques, ainsi qu’hautement spécifique du genre Vibrio. La méthode a ensuite été appliquée avec succès à la détection des Vibrio dans des échantillons environnementaux, collectés dans la lagune de Salses-Leucate. Un second format d’hybridation, basé sur la compétition entre les acides nucléiques cibles et la sonde capture pour la sonde signal, a ensuite été envisagé en utilisant aussi bien une transduction optique qu’électrochimique. En parallèle, des méthodes de PCR quantitative en temps réel ont été mises au point afin de servir de références pour la validation des génocapteurs. / Mass mortality events affecting the Pacific oyster Crassostreae gigas on French coasts since 2008 have been associated to some Vibrio species. These mortalities, particularly severe and sudden in the mediterranean lagoons, can reach 80 to 100% of the oyster production threatening the sustainability of this activity. An environmental monitoring of these bacteria appears essential and, for this purpose, innovative analytical methods have to be developed as alternative to classical techniques, in order to allow the rapid and in real time monitoring of Vibrio in the coastal aquatic environments. In this context, the objective of the thesis was to design genosensors as analytical tools for Vibrio detection and quantification in aquatic ecosystems. In a first step, a system based on a « sandwich » hybridization format, in which nucleic acid targets were bound between an immobilized capture probe and a labeled signal probe, coupled with an optical detection method, was developed. After experimental condition optimization, the test showed high sensitivity with a limit of detection of 5 ng.µL-1 of nucleic acids and was highly specific to Vibrio spp. The method was then successfully applied to Vibrio detection in environmental samples collected in Salses-Leucate lagoon. A second hybridization format, based on a competition between the targeted nucleic acids and the capture probe for the signal probe has been considered using both optical and electrochemical transductions. Concurrently with the development of genosensors, quantitative real-time PCR have been designed as reference methods.
424

Automated Species Classification Methods for Passive Acoustic Monitoring of Beaked Whales

LeBien, John 20 December 2017 (has links)
The Littoral Acoustic Demonstration Center has collected passive acoustic monitoring data in the northern Gulf of Mexico since 2001. Recordings were made in 2007 near the Deepwater Horizon oil spill that provide a baseline for an extensive study of regional marine mammal populations in response to the disaster. Animal density estimates can be derived from detections of echolocation signals in the acoustic data. Beaked whales are of particular interest as they remain one of the least understood groups of marine mammals, and relatively few abundance estimates exist. Efficient methods for classifying detected echolocation transients are essential for mining long-term passive acoustic data. In this study, three data clustering routines using k-means, self-organizing maps, and spectral clustering were tested with various features of detected echolocation transients. Several methods effectively isolated the echolocation signals of regional beaked whales at the species level. Feedforward neural network classifiers were also evaluated, and performed with high accuracy under various noise conditions. The waveform fractal dimension was tested as a feature for marine biosonar classification and improved the accuracy of the classifiers. [This research was made possible by a grant from The Gulf of Mexico Research Initiative. Data are publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at https://data.gulfresearchinitiative.org.] [DOIs: 10.7266/N7W094CG, 10.7266/N7QF8R9K]
425

EVALUATION OF A SEQUENTIAL POND SYSTEM FOR DETENTION AND TREATMENT OF RUNOFF AT SKYPARK, SANTA'S VILLAGE

Caporuscio, Elizabeth 01 December 2018 (has links)
Understanding the extent to which human activities impact surface water resources has become increasingly important as both human population growth and related landscape changes impact water quality and quantity across varying geographical scales. Skypark, Santa’s Village is a 233.76-acre tourism-based outdoor recreation area located in Skyforest, California residing within the San Bernardino National Forest. The park is situated at Hooks Creek, the headwaters of the Mojave River Watershed, and is characterized by a diverse landscape that includes forest cover and human development, including impervious surfaces, a restored meadow, and recreational trails. In 2016, Hencks Meadow was considered degraded by human activity and restored by the Natural Resources Conservation Services (NRCS) using best management practices (BMPs) to manage stormwater runoff and mitigate pollutants entering recreational downstream surface water. Three BMP detention basins were constructed to store and improve water quality from stormwater runoff. The purpose of this study is to observe the extent to which the engineered BMP detention basins design were effective in mitigating stormwater pollution from entering Hooks Creek. Over a six to eight month period (January to August), ponds were tested in situ bi-weekly for temperature (ºC), dissolved oxygen (mg/L), pH, turbidity (NTU), conductivity (µS/cm), nitrate (mg/L), and ammonium (mg/L), with additional laboratory tests for total suspended solids (mg/L), total dissolved solids (mg/L), chemical oxygen demand (mg/L), total coliform (MPN/100mL), Escherichia coli (MPN/100mL), and trace metals (µg/L). The results of this study support that the BMP design is improving surface stormwater runoff from impervious surfaces before it enters Hooks Creek. Findings could also promote the design and implementation of stormwater BMP detention basins at other site locations where water degradation is evident. Furthermore, this research can be used to promote the necessary improvement of water quality and quantity on a widespread geographical scale.
426

OCCURRENCE AND POTENTIAL SOURCES OF Cd, Cu, AND Pb IN REACH 6 OF THE SANTA ANA RIVER

Mamari, May 01 September 2019 (has links)
The Santa Ana River (SAR) is the largest river in Southern California. The flow of the SAR begins in the San Bernardino Mountains and discharges into the Pacific Ocean at Huntington Beach. The SAR contains one of the most essential and rare biodiversity hotspots on earth. In order to protect the wildlife, and suit population demands, the SAR must meet the Clean Water Act (CWA) regulations. The SAR Reach 6 is the uppermost segment of the river, and is currently listed under the CWA 303(d) List for impaired water due to contamination of cadmium, copper, and lead from an unknown source based on limited data provided in 1997 by the San Bernardino County Flood Control District (SBCFCD). This project focused on confirming the contemporary occurrence and identifying the potential source(s) of Cd, Cu, and Pb by comparing new water sample data with that of previous studies The analysis of previous data identified an interesting correlation between high water hardness and elevated lead levels. The new results from this study suggest that there continues to be a source of these metals in the upper parts of Reach 6 of the SAR. Moreover, the limited data obtained in this study suggests that the source of the contamination is upstream to the northeast of the primary sampling site, possibly on private lands. Future, more comprehensive studies will be required to determine whether Reach 6 of the SAR should remain on the 303(d) list. Source identification if necessary, will be a further challenge.
427

An Investigation of Urban Mobile Source Aerosol Using Optical Properties Measured by CRDT/N: Diesel Particulate Matter and the Impact of Biodiesel

Wright, Monica Elizabeth 06 December 2012 (has links)
Mobile source emissions are a major contributor to global and local air pollution. Governments and regulatory agencies have been increasing the stringency of regulations in the transportation sector for the last ten years to help curb transportation sector air pollution. The need for regulations has been emphasized by scientific research on the impacts from ambient pollution, especially research on the effect of particulate matter on human health. The particulate emissions from diesel vehicles, diesel particulate matter (DPM) is considered a known or probable carcinogen in various countries and increased exposure to DPM is linked to increased cardiovascular health problems in humans. The toxicity of vehicle emissions and diesel particulate emissions in particular, in conjunction with an increased awareness of potential petroleum fuel shortages, international conflict over petroleum fuel sources and climate change science, have all contributed to the increase of biodiesel use as an additive to or replacement for petroleum fuel. The goal of this research is to determine how this increased use of biodiesel in the particular emission testing setup impacts urban air quality. To determine if biodiesel use contributes to a health or climate benefit, both the size range and general composition were investigated using a comprehensive comparison of the particulate component of the emissions in real time. The emissions from various biodiesel and diesel mixtures from a common diesel passenger vehicle were measured with a cavity ring-down transmissometer (CRDT) coupled with a condensation particle counter, a SMPS, a nephelometer, NOx, CO, CO2, and O3 measurements. From these data, key emission factors for several biodiesel and diesel fuel mixtures were developed. This approach reduces sampling artifacts and allows for the determination of optical properties, particle number concentration, and size distributions, along with several important gas phase species' concentrations. Findings indicate that biodiesel additions to diesel fuel do not necessarily have an air quality benefit for particulate emissions in this emission testing scenario. The often cited linear decrease in particulate emissions with increasing biodiesel content was not observed. Mixtures with half diesel and half biodiesel tended to have the highest particulate emissions in all size ranges. Mixtures with more than 50% biodiesel had slightly lower calculated mass for light absorbing carbon, but this reduction in mass is most likely a result of a shift in the size of the emission particles to a smaller size range, not a reduction in the total number of particles. Evaluation of the extensive optical properties from this experimental set-up indicates that biodiesel additions to diesel fuel has an impact on emission particle extinction in both visible and near-IR wavelengths. The B99 mixture had the smallest emission factor for extinction at 532 nm and at 1064 nm. For the extinction at 532 nm, the trend was not linear and the emission factor peaked at the B50 mixture. Results from intensive properties indicate that emissions from B5 and B25 mixtures have Ångström exponents close to 1, typical for black carbon emissions. The mixtures with a larger fraction of biodiesel have Ångström exponent values closer to 2, indicating more absorbing organic matter and/or smaller particle size in the emissions. Additional experimental testing should be completed to determine the application of these results and emission factors to other diesel vehicles or types of diesel and biodiesel fuel mixtures.
428

The Effects of Urbanization and Human Disturbance Upon Plant Community Structure and Bird Species Richness, Diversity, and Abundance in a Natural Forested Area (Forest Park) in Portland, Oregon

Broshot, Nancy Ellen 01 January 1999 (has links)
The effects of urbanization and continual human disturbance on the plant and avian communities of Forest Park and forested lands surrounding Portland, Oregon, were studied. I examined characteristics of plant and avian communities at 25 sites, 24 which were in Forest Park and surrounding areas and one which was in the Ancient Forest Preserve (old-growth stand) northwest of Forest Park. Data were analyzed using multiple regression, ANOV A, and Bonferonni/Dunn. Seven variables were selected representing different urbanization gradients. An additional covariable coded for the old-growth stand, allowing it to be used as a control. Many tree variables, especially those related to shade-tolerant species, were positively correlated with both the distance from downtown Portland and the number of houses in the surrounding area, and negatively correlated with the distance from the nearest forest edge; however, many shrub and herbaceous variables were negatively correlated with the distance from downtown Portland. Species diversity for herbaceous and shrub species was greater at more urban sites, but diversity of trees was lower at more urban sites. There were significantly more non-native species of plants in the city section. I found significantly fewer saplings and small trees, especially shade-tolerant species, in the section of Forest Park closest to downtown Portland, although tree mortality was positively correlated with distance from Portland. Summer bird data revealed significant increases in the abundances of urban and edge species at more urban sites, with concomitant reductions in forest species. There were significantly more ground gleaning birds and short distance migratory species. I also found a significantly greater abundance of birds in the old-growth stand during the winter. This increase was positively correlated with the depth of snow in the nearby Cascade Mountains. My results indicate that Forest Park is apparently progressing in a normal successional pattern with the exception of the city section. The reduction in shade tolerant saplings and small trees in the city section suggest that rate of succession has been slower at more urban sites. Avian data suggest that urbanization affects bird species abundance and guild composition in the more urban areas.
429

Integrated, Intelligent Sensor Fabrication Strategies for Environmental Monitoring

Suzuki, Takeharu, n/a January 2004 (has links)
The humidity, temperature, wind speed/direction micro sensors can be manufactured individually, resulting in three individual substrates. The integration of the three sensors into a single substrate is a vital challenge to achieve an integrated intelligent sensor so called a multiple sensor. This requires the integration of process flows and is a major challenge because adequate sensor performance must be maintained. Polyimide was selected as a humidity sensing material for its compatibility with conventional integrated circuit fabrication technology, negligible temperature dependence and good resistance against contamination. Nickel was selected for the temperature and wind speed/direction sensor because of its useful temperature coefficient and the advantage of its cost. Since the known wet etchant for nickel requires hard-baked photoresist, a method which does not attack the polyimide while removing the photoresist must be developed. The method developed for etching nickel employs hard-bake-free photoresist. Other challenge was ensuring good thermal isolation for the wind speed/direction sensor fabricated on a silicon nitride layer preformed on top of a silicon wafer. Since silicon acts as a good heat sink, the silicon under the sensor was etched entirely away until the silicon nitride layer was reached. This structure achieved good thermal isolation resulting in small power consumption. This low power feature is essential for sensors deployed in fields where power access or replacement of power sources is restricted. This structure was compared with the structure created by polyimide plateau on a silicon nitride layer coated on a silicon substrate as a function of power consumption. Based on the examination of thermal isolation, the multiple sensor utilizing a MEMS technique was fabricated with a single-sided mask aligner. The characteristics of humidity sensors fabricated with polyimide were examined in detail with respect to variations of electrode structures, improvement of sensitivity, effect of process temperature, temperature and frequency dependence, and stability. The humidity sensor constructed with O2 plasma treated polyimide resulted an improvement in sensitivity and hysteresis. The investigation using XPS, FTIR and AFM concluded the chemical modification of polyimide played an important role in this improvement. The design, fabrication and results of a series of humidity sensors are quantified. There is always no unique packaging solution for sensors because of the application-specific nature of the sensors. This intelligent environmental monitoring system was designed to accommodate both an environmental sensor and its signal conditioning electronics circuitry (SICONEC) into a single package. The environmental sensors need direct exposure to the environment while SICONEC needs a sealed encapsulation to avoid environmental damage. A new style of packaging addressing these requirements was demonstrated using a hot embossing machine. The hot embossing machine was used to embed an integrated circuit (IC) in a bare die condition into a polycarbonate (PC) sheet. In this case, the IC was flipped down against the PC, which protects the front side of the IC from the environmental damages. In a test phase, a die containing operational amplifiers was embossed into the PC. A humidity sensor and surface mount resisters were placed on the same surface of the PC to test the validity of this new technique. Interconnection between the embossed die and the humidity sensor was established using bonding wires. Copper tracks were also used to ensure all electrical connections for the die, the humidity sensor and the resistors. The results clarified the method developed. Details of process methods, issues and further potential improvement are reported.
430

Making water information relevant on local to global scale – the role of Information Systems for Integrated Water Management

Hannerz, Fredrik January 2008 (has links)
<p>Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.</p>

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