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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.
1

Developing a Prototype Web-based Application for Non-Point Source Pollution Assessment in the Songtao Watershed, Hainan, China

Dong, Yunwei 23 January 2009 (has links)
The Songtao reservoir, located in the center of Hainan province, is one of the ten biggest reservoirs in China. Since agriculture is the main industry in the watershed, non-point source (NPS) pollution is the primary pollutant source affecting water quality in the reservoir. A scientific approach is required to assess NPS pollution in the Songtao watershed in order to support planning and decision making process related to land use and water resource management. This study compared several commonly used NPS hydrological models in order to identify a suitable model for NPS pollution analysis in the Songtao reservoir. The Soil and Water Assessment Tool (SWAT) was selected as the model to be used in this research. In order to put the SWAT model to practical use, a prototype web-based application was developed to help officers in local government in China to use the SWAT model in their decision making process. In addition, spatial and non spatial data about the Songtao watershed area were collected for the SWAT model. Despite data limitations, ArcSWAT software was employed to develop relative scenarios to assess the NPS pollution in the reservoir. One land use scenario was developed to identify an environmentally sensitive basin in the Songtao watershed and the other was created to demonstrate the consequences of over-exploiting forest land in local area. The limitations of using SWAT model in Hainan province were discussed. Further research opportunities such as data collection and model calibration and validation were identified. In addition, possible improvements to the web-based application were presented.
2

Developing a Prototype Web-based Application for Non-Point Source Pollution Assessment in the Songtao Watershed, Hainan, China

Dong, Yunwei 23 January 2009 (has links)
The Songtao reservoir, located in the center of Hainan province, is one of the ten biggest reservoirs in China. Since agriculture is the main industry in the watershed, non-point source (NPS) pollution is the primary pollutant source affecting water quality in the reservoir. A scientific approach is required to assess NPS pollution in the Songtao watershed in order to support planning and decision making process related to land use and water resource management. This study compared several commonly used NPS hydrological models in order to identify a suitable model for NPS pollution analysis in the Songtao reservoir. The Soil and Water Assessment Tool (SWAT) was selected as the model to be used in this research. In order to put the SWAT model to practical use, a prototype web-based application was developed to help officers in local government in China to use the SWAT model in their decision making process. In addition, spatial and non spatial data about the Songtao watershed area were collected for the SWAT model. Despite data limitations, ArcSWAT software was employed to develop relative scenarios to assess the NPS pollution in the reservoir. One land use scenario was developed to identify an environmentally sensitive basin in the Songtao watershed and the other was created to demonstrate the consequences of over-exploiting forest land in local area. The limitations of using SWAT model in Hainan province were discussed. Further research opportunities such as data collection and model calibration and validation were identified. In addition, possible improvements to the web-based application were presented.
3

none

Pai, Chih-Hua 20 August 2002 (has links)
none
4

Quercetin and Chlorogenic Acid Mitigate DSS-Induced Changes in Expression of Select Pro-Inflammatory Cytokines and Short Chain Fatty Acid Transporter Genes

Piefer, Leigh 2012 August 1900 (has links)
Quercetin (Q) and chlorogenic acid (CA), two bioactive compounds found in stonefruits, may protect against inflammation and cancer because of anti-cancer, anti-oxidant, and anti-inflammatory properties. Since these compounds reach the colon undigested, they affect the luminal environment before they are metabolized by the microbiota and transported into epithelial cells. We hypothesized that Q and CA may suppress expression of pro-inflammatory molecules, alter the luminal environment, and alter the cell cycle, thereby protecting against injury/colitis. To test this hypothesis, 63 male weanling rats were given one of three diets (basal, 0.45% Q, 0.05% CA). After 3 wk of acclimation, colitis was induced in 11 rats/diet [3% dextran sodium sulfate (DSS), 48 h, 3 treatments, 2 wk separation] and 10 rats/diet served as control (0% DSS). All rats were terminated at wk 9. Measurements included: fecal moisture content, fecal short chain fatty acid (SCFA) concentrations (gas chromatography), epithelial injury and inflammation in the distal colon, proliferation (PCNA), and NF-kappaB activity (ELISA method) and gene expression (real time RT-PCR) in mucosal scrapings. Fecal moisture content was significantly increased by DSS exposure (p<0.05), and never returned to control levels. Fecal SCFA concentrations also increased with DSS (acetate, p<0.05; butyrate, p<0.05). Increased SCFA concentrations could indicate decreased SCFA uptake. Experimental diets were able to mitigate DSS-induced decreases in SLC5A8 (SCFA transporter) expression. DSS significantly increased injury (p<0.0001) and inflammation (p<0.01) scores. Compared to the basal diet, CA decreased NF-kappaB activity in DSS-treated rats (p<0.05). Q and CA may maintain healthy regulation of NF-kappaB through maintaining expression levels of IkappaBalpha and Tollip, molecules that inhibit NF-kappaB activation. Q and CA mitigated DSS-induced increases in pro-inflammatory cytokine expression, specifically IL-1. Q enhanced expression of injury-repair molecule FGF-2 (p<0.01), but neither diet nor DSS treatment altered proliferation. Although Q and CA did not protect against DSS-induced increases in injury and inflammation scores or fecal SCFA concentrations, their influence on expression of injury repair molecules, pro-inflammatory cytokines, SCFA transport proteins, and NF-kappaB inhibitory molecules suggests beneficial influences on major pathways involved in DSS-induced injury/inflammation. The combined benefit of these compounds could have additive/synergistic effects and, therefore, deserve further examination.
5

Risk factors of neonatal mortality in Navrongo DSS in Ghana between 2001 and 2005

Maraga, Seri Emily 22 March 2011 (has links)
MSc (Med), Population-Based Field Epidemiology, Faculty of Health Sciences, University of the Witwatersrand / Background Improvements in the health status of children have resulted in a substantive reduction in under-five mortality by two-thirds between 1960 and 1990. However this reduction is favourable for children after the first year in life, with little decrease in the neonatal period. Every year, about 4 million children die within the first 28 days of life, the first week (0-7 days) posing the highest risk. The Fourth Millennium Development Goal emphasises a reduction in child mortality by two-thirds by 2015, however this goal cannot be met because neonatal deaths continue to increase. It is therefore important to make available information on risk factors and the main causes of death that exist at a community level so that appropriate health policies are devised to reduce the mortality burden faced by neonates. Objective The study investigates the relationship between household and maternal socio-demographic characteristics with neonatal mortality in the Kassena-Nankana District from 2001 to 2005. The specific objectives were; (1) To calculate the neonatal mortality rates in the Kassena-Nankana District from 2001 to 2005, (2) To determine the causes of neonatal death for years 2003 to 2005, and (3) To assess the association of household characteristics and maternal socio-demographic characteristics with neonatal deaths in the Kassena-Nankana District from 2001 to 2005. Methods Data from Navrongo DSS in Ghana was used for the analysis. A total of 19 340 live births born from 15 224 households were registered between 1st January 2001 to 31st December 2005. Of these 551 died before the 28th day after birth. The outcome, neonatal mortality was coded as a binary variable and took values 1 if the child died and 0 if the child survived. Neonatal mortality rates were calculated by dividing the total number of deaths for a particular year by the total number of live births for that year, multiplied by 1000. Cause of death data were collected using neonatal specific verbal autopsies. Cause-specific neonatal mortality rates were calculated using physician coding to a list of cause of deaths based on the 9th International Classification for Diseases (ICD). Using the mother‟s household characteristics and assets ownership, a wealth index was constructed as proposed by Filmer and Pritchett to estimate socio-economic status. Chi-square (x2) test at 5% significant level was also done to compare the maternal socio-demographic and neonatal characteristics by neonatal mortality. Logistic regression models were fitted to assess the association between (i) neonatal mortality and socio-economic status (SES) and (ii) between neonatal mortality and maternal as well as neonatal risk factors, while adjusting for potential confounders. Health equity was measured using the concentration index (CI) and the poorest-poor ratio (PPR). Results: The overall neonatal mortality rate for the whole study period was 29 per 1000 live births. Most deaths (65.9%) occurred outside the health facility and most occurred in the early neonatal period (0-7 days). Infectious diseases (n=98, 33.2%), birth injuries (n=28, 9.5%) and prematurity (n=29, 9.8%) were the main causes of neonatal deaths. In the multivariate analysis maternal characteristic that showed an association with mortality were place of residence, SES, birth order and the type of birth outcome. Such that children who died were more often from the rural areas compared to in the urban areas (AOR=2.24 95% CI=1.16-4.34 P=0.016). Children who died were more often from a multiple birth outcome compared to those from a single birth outcome (AOR=0.20 95% CI=0.14-0.28 P<0.0001). SES was found to be protective against neonatal mortality (AOR=0.70 95% CI= 0.51–0.96 P=0.026). By birth order, children who died were more often from the 1st birth order compared to children of birth orders; 2-3 (AOR=0.60 95% CI=0.44-0.81 P=0.001), 4-5 (AOR=0.56 95% CI=0.38-0.84 P=0.005) and 6+ birth order (AOR=0.50 95% CI=0.31-0.8 P=0.005). A measure of health equity gave a C.I of -0.07 and PPR of 1.29 implying that neonatal mortality was high amongst the poorest households than the better ones. Conclusion The study showed that neonatal mortality was high in the rural areas and in the poorest households. Efforts to alleviate the burden of neonatal mortality at a community level should focus on improving living standards for poorest in the community. Also educating women on child health care and making them aware of high risk pregnancy age-groups will help minimize risky pregnancies which in turn will reduce neonatal deaths.
6

Optimization of Disaggregated Space Systems Using the Disaggregated Integral Systems Concept Optimization Technology Methodology

Wagner, Katherine Mott 10 July 2020 (has links)
This research describes the development and application of the Disaggregated Integral Systems Concept Optimization Technology (DISCO-Tech) methodology. DISCO-Tech is a modular space system design tool that focuses on the optimization of disaggregated and non-traditional space systems. It uses a variable-length genetic algorithm to simultaneously optimize orbital parameters, payload parameters, and payload distribution for space systems. The solutions produced by the genetic algorithm are evaluated using cost estimation, coverage analysis, and spacecraft sizing modules. A set of validation cases are presented. DISCO-Tech is then applied to three representative space mission design problems. The first problem is the design of a resilient rideshare-manifested fire detection system. This analysis uses a novel framework for evaluating constellation resilience to threats using mixed integer linear programming. A solution is identified where revisit times of under four hours are achievable for $10.5 million, one quarter of the cost of a system manifested using dedicated launches. The second problem applies the same resilience techniques to the design of an expanded GPS monitor station network. Nine additional monitor stations are identified that allow the network to continuously monitor the GPS satellites even when five of the monitor stations are inoperable. The third problem is the design of a formation of satellites for performing sea surface height detection using interferometric synthetic aperture radar techniques. A solution is chosen that meets the performance requirements of an upcoming monolithic system at 70% of the cost of the monolithic system. / Doctor of Philosophy / Civilians, businesses, and the government all rely on space-based resources for their daily operations. For example, the signal provided by GPS satellites is used by drivers, commercial pilots, soldiers, and more. Communications satellites provide phone and internet to users in remote areas. Weather satellites provide short-term forecasting and measure climate change. Because of the importance of these and other space systems, it is necessary that they are designed in an efficient, reliable, and cost-effective manner. The Disaggregated Integral Systems Concept Optimization Technology (DISCO-Tech) is introduced as a means of designing these space systems. DISCO-Tech optimizes various aspects of the space mission, including the number of satellites needed to complete the mission, the location of the satellites, and the sensors that each satellite needs to accomplish its mission. This dissertation describes how DISCO-Tech works, then applies DISCO-Tech to several example missions. The first mission uses satellites to monitor forest fires in California. In order to reduce the cost of this mission, the satellites share launch vehicles with satellites from other, unrelated missions. Next, DISCO-Tech is used to choose the placement of new ground stations for GPS satellites. Because GPS is an important asset, this study also assesses the performance of the network of ground stations when some of the stations are inoperable. Finally, DISCO-Tech is used to design a group of satellites that measure sea level, since sea level is important for climatology research. A design is presented for a group of satellites that perform these measurements at a lower cost than a planned mission that uses a single satellite.
7

An Application of Decision Support System of Developers for Land Development.

Kuen-Lang, Chiang 30 July 2007 (has links)
Abstract Construction investment is regarded as the leading cause in Real Estate industry for a long time. During the process, land development is an important factor for company's profitability. However, professions in this industry always rely on personal experience to estimate the land development potential. In most cases, owners or upper management are the ones to make the decision. Not only the decision conflict the open policy, it also lack of the base from lesson learns after the project wrap up. It limited the build up of experience with in companies. After interviewing industry experts, we found that the reasons people rely purely on experience among land estimate industry, besides the unique characteristic of land, accuracy and trust worthy of information, is limited to estimation during development; especially data of the direct cost, indirect cost, annual interest rate, and return ratio is missing the land estimation technical specification. Thus, people in current industry normally use personal experience or the reference material from government. Project budget in construction industry normally is pretty huge, management budget is occupied in a small percentage; thus, members normally do not want to spend time to analyze in detail in the beginning. This research base on documents and experts interview, it verifies and gather analysis of land development estimation. At the same time, it also gathers current ERP¡]Enterprise Resource Planing¡^ to get the real internal data. Using DSS system to assist members to process decision-making characteristics and What-If functions in which supports decision maker's decision. Utilize historical statistics and market fluctuation to process estimation and provide project data and comparison pie chart. This will provide the decision makers more effective comparison to different projects. Use land developing analysis estimate to establish an estimation structure and foundation for business to adjust accordingly when government regulation changes. An updated estimation way of Decision support system will provides an advanced tool for land developers. This will help decision makers in land development estimation to reduced the blind spots and mistake due to overly rely on personal experiences.
8

The potential protective role of caveolin-1 in intestinal inflammation in experimental colitis

Weiss, Carolyn Ruth 10 January 2013 (has links)
Background: Caveolin-1 (Cav-1), the major component of caveolae, is a multifunctional scaffolding protein that serves as a platform for the cell’s signal-transduction and plays a role in inflammation. However, its role in inflammatory bowel disease (IBD), a chronic inflammatory condition in the gastrointestinal tract, is not clear. A recent study shows that Cav-1 mediates angiogenesis in dextran sodium sulphate (DSS)-induced colitis. These results contradict our data, in which Cav-1 levels decreased significantly in 2,4,6-trinitrobenzene sulphonic acid (TNBS)–induced colitis. Methods: To test whether Cav-1 is involved in IBD pathogenesis, various models representing different dominant Th subtype responses and mimicking the immune pathologic mechanisms of different clinical IBD setting were employed: acute colitis was induced by intra-rectal administration of a single dose of TNBS in BALB/c and C57BL/6J mice, or by drinking 3% DSS water for 6 days in C57BL/6J mice. Chronic colitis was induced by administration of TNBS once a week for 7 weeks in BALB/c mice. To assess the effects of complete loss of Cav-1, Cav-1 knock-out (Cav-1-/-) and control wild-type C57BL/6J mice received a single TNBS administration. To further test the possible role of Cav-1, one of two peptides (that either mimicked (Caveolin scaffolding domain; CSD) or antagonized (Caveolin-1 binding domain; CBD1) Cav-1)) was administered intraperitoneally to mice receiving TNBS. Body weight and clinical scores were monitored. Colon Cav-1 and pro-inflammatory cytokine levels were quantified by ELISA. Inflammation was evaluated through histological analysis. Results: Cav-1 levels in mouse colon tissue were significantly decreased in TNBS-induced colitis mice when compared to normal mice and also inversely correlated with colon inflammation and cytokine levels. Furthermore, a loss of Cav-1 (Cav-1-/-) showed increased clinical and inflammatory scores and increased body weight loss. Mice receiving peptides to alter Cav-1 levels, showed surprising effects. The mimicking peptide (CSD) showed decreased Cav-1 levels, while the antagonizing peptide (CBD1) showed increased Cav-l levels. These changes in levels were associated with clinical and inflammatory scores and body weight loss that supported the TNBS-induced data. DSS-induced colitis mice showed increased disease activity index, however no significant difference in Cav-1 levels was found between colitis and normal mice. Conclusions: Cav-1 plays an important role in the protection of TNBS-induced colitis, but not in DSS-induced colitis, an entirely different result from a previous report, suggesting that enhancement of Cav-1 expression and functions may be beneficial to IBD treatment in some specific clinical settings. Further studies are warranted.
9

The potential protective role of caveolin-1 in intestinal inflammation in experimental colitis

Weiss, Carolyn Ruth 10 January 2013 (has links)
Background: Caveolin-1 (Cav-1), the major component of caveolae, is a multifunctional scaffolding protein that serves as a platform for the cell’s signal-transduction and plays a role in inflammation. However, its role in inflammatory bowel disease (IBD), a chronic inflammatory condition in the gastrointestinal tract, is not clear. A recent study shows that Cav-1 mediates angiogenesis in dextran sodium sulphate (DSS)-induced colitis. These results contradict our data, in which Cav-1 levels decreased significantly in 2,4,6-trinitrobenzene sulphonic acid (TNBS)–induced colitis. Methods: To test whether Cav-1 is involved in IBD pathogenesis, various models representing different dominant Th subtype responses and mimicking the immune pathologic mechanisms of different clinical IBD setting were employed: acute colitis was induced by intra-rectal administration of a single dose of TNBS in BALB/c and C57BL/6J mice, or by drinking 3% DSS water for 6 days in C57BL/6J mice. Chronic colitis was induced by administration of TNBS once a week for 7 weeks in BALB/c mice. To assess the effects of complete loss of Cav-1, Cav-1 knock-out (Cav-1-/-) and control wild-type C57BL/6J mice received a single TNBS administration. To further test the possible role of Cav-1, one of two peptides (that either mimicked (Caveolin scaffolding domain; CSD) or antagonized (Caveolin-1 binding domain; CBD1) Cav-1)) was administered intraperitoneally to mice receiving TNBS. Body weight and clinical scores were monitored. Colon Cav-1 and pro-inflammatory cytokine levels were quantified by ELISA. Inflammation was evaluated through histological analysis. Results: Cav-1 levels in mouse colon tissue were significantly decreased in TNBS-induced colitis mice when compared to normal mice and also inversely correlated with colon inflammation and cytokine levels. Furthermore, a loss of Cav-1 (Cav-1-/-) showed increased clinical and inflammatory scores and increased body weight loss. Mice receiving peptides to alter Cav-1 levels, showed surprising effects. The mimicking peptide (CSD) showed decreased Cav-1 levels, while the antagonizing peptide (CBD1) showed increased Cav-l levels. These changes in levels were associated with clinical and inflammatory scores and body weight loss that supported the TNBS-induced data. DSS-induced colitis mice showed increased disease activity index, however no significant difference in Cav-1 levels was found between colitis and normal mice. Conclusions: Cav-1 plays an important role in the protection of TNBS-induced colitis, but not in DSS-induced colitis, an entirely different result from a previous report, suggesting that enhancement of Cav-1 expression and functions may be beneficial to IBD treatment in some specific clinical settings. Further studies are warranted.
10

Establishment of a mouse model of colitis and its use to evaluate the anti-inflammatory effects of two ghrelin peptides

Taufiq, Samia January 2009 (has links)
Ghrelin is a gut-brain peptide hormone that induces appetite, stimulates the release of growth hormone, and has recently been shown to ameliorate inflammation. Recent studies have suggested that ghrelin may play a potential role in inflammation-related diseases such as inflammatory bowel diseases (IBD). A previous study with ghrelin in the TNBS mouse model of colitis demonstrated that ghrelin treatment decreased the clinical severity of colitis and inflammation and prevented the recurrence of disease. Ghrelin may be acting at the immunological and epithelial level as the ghrelin receptor (GHSR) is expressed by immune cells and intestinal epithelial cells. The current project investigated the effect of ghrelin in a different mouse model of colitis using dextran sodium sulphate (DSS) – a luminal toxin. Two molecular weight forms of DSS were used as they give differing effects (5kDa and 40kDa). Ghrelin treatment significantly improved clinical colitis scores (p=0.012) in the C57BL/6 mouse strain with colitis induced by 2% DSS (5kDa). Treatment with ghrelin suppressed colitis in the proximal colon as indicated by reduced accumulative histopathology scores (p=0.03). Whilst there was a trend toward reduced scores in the mid and distal colon in these mice this did not reach significance. Ghrelin did not affect histopathology scores in the 40kDa model. There was no significant effect on the number of regulatory T cells or TNF-α secretion from cultured lymph node cells from these mice. The discovery of C-terminal ghrelin peptides, for example, obestatin and the peptide derived from exon 4 deleted proghrelin (Δ4 preproghrelin peptide) have raised questions regarding their potential role in biological functions. The current project investigated the effect of Δ4 peptide in the DSS model of colitis however no significant suppression of colitis was observed. In vitro epithelial wound healing assays were also undertaken to determine the effect of ghrelin on intestinal epithelial cell migration. Ghrelin did not significantly improve wound healing in these assays. In conclusion, ghrelin treatment displays a mild anti-inflammatory effect in the 5kDa DSS model. The potential mechanisms behind this effect and the disparity between these results and those published previously will be discussed.

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