Industrial Discharges of Metals in Kigali, Rwanda, and the Impact on Drinking Water Quality

Rwanda is a landlocked country located in Africa's Central-East Great Lakes region. It has a population of 7.5 million which occupies 26,338 km'. Its population density (285/km') is one of the highest in the world and has prompted fear of a rapid degradation of the ecosystem. There are no central sewer systems in Rwanda. The use of pit latrines and septic tanks is common in urban and rural areas. People still defecate in the fields (World Bank, 1989). Less than half of the urban population is served by a central water supply. The majority of people get their water untreated from rivers that have been polluted by chemicals and human excreta. In and around the capital city of Kigali, there is a concentration of people, farms, and industries which discharge wastewater into the Nyabarongo River and its tributaries. The Nyabarongo River, a tributary of the Nile, empties into the Akagera River which flows into Lake Victoria. Nyabarongo River water is used for drinking water, cooking, bathing, and agriculture in the Kigali area. There has been very little monitoring of the water quality of the Nyabarongo River and of industrial outfalls located on tributaries of the Nyabarongo River. As a first step in understanding the water quality of the Nyabarongo River, wastewater samples were collected in 1993 from industrial outfalls located on tributaries of the Nyabarongo River. Most of the facilities sampled had no wastewater treatment. The impact of these discharges on the water quality of the Nyabarongo River was evaluated.

Impact of Water Supply and Sanitation on Diarrheal Morbidity among Young Children in the Socioeconomic and Cultural Context of Rwanda (Africa)

This project studied the frequency and of water contamination at the source, during transportation, and at home to determine the causes of contamination and its impact on the health of children aged 0 to 5 years. The methods used were construction of the infrastructure for three sources of potable water, administration of a questionnaire about socioeconomic status and sanitation behavior, anthropometric measurement of children, and analysis of water and feces. The contamination, first thought to be only a function of rainfall, turned out to be a very complex phenomenon. Water in homes was contaminated (43.4%) with more than 1100 total coliforms/100 ml due to the use of unclean utensils to transport and store water. This socio-economic and cultural problem should be ad- dressed with health education about sanitation, The latrines (found in 43.8% of families) presented a double-edged problem. The extremely high population density reduced the surface area of land per family, which resulted in a severe nutritional deficit (15% of the children) affecting mainly young children, rendering them more susceptible to diarrhea (three episodes/child/year).

An analysis of the themes of environmental sustainability in the United States curriculum science content standards

This study examined how the themes of environmental sustainability are evident in the national, state and local standards that guide k–12 science curriculum. The study applied the principles of content analysis within the framework of an ecological paradigm. In education, an ecological paradigm focuses on students' use of a holistic lens to view and understand material. The intent of this study was to analyze the seventh grade science content standards at the national, state, and local textbook levels to determine how and the extent to which each of the five themes of environmental sustainability are presented in the language of each text. The themes are: (a) Climate Change Indicators, (b) Biodiversity, (c) Human Population Density, (d) Impact and Presence of Environmental Pollution, (e) Earth as a Closed System. The research study offers practical insight on using a method of content analysis to locate keywords of environmental sustainability in the three texts and determine if the context of each term relates to this ecological paradigm. Using a concordance program, the researcher identified the frequency and context of each vocabulary item associated with these themes. Nine chi squares were run to determine if there were differences in content between the national and state standards and the textbook. Within each level chi squares were also run to determine if there were differences between the appearance of content knowledge and skill words. Results indicate that there is a lack of agreement between levels that is significant p < .01. A discussion of these results in relation to curriculum development and standardized assessments followed. The study found that at the national and state levels, there is a lack of articulation of the goals of environmental sustainability or an ecological paradigm. With respect to the science textbook, a greater number of keywords were present; however, the context of many of these keywords did not align with the discourse of an ecological paradigm. Further, the environmental sustainability themes present in the textbook were limited to the last four chapters of the text. Additional research is recommended to determine whether this situation also exists in other settings.

The electoral geography of the Slovak Republic: A comparison of the 1994, 1998, and 2002 parliamentary elections

In what can rightly be said to be one of the most dramatic geopolitical shifts in modern times, the collapse of communist regimes in Central Europe and the former Soviet Union brought about dramatic changes in the entire region. As a consequence, wide ranging political, economic, and social transformations have occurred in almost all of these countries since 1989. The Slovak Republic, as a newly democratic country, went through the establishment of the electoral and party systems that are the central mechanisms to the formation of almost all modern democratic governments. The primary research purpose of this dissertation was to describe and explain regional variations in party support during Slovakia’s ten years of democratic transformation. A secondary purpose was to relate these spatial variations to the evolution of political parties in the post-independence period in light of the literature on transitional electoral systems. Research questions were analyzed using both aggregate and survey data. Specifically, the study utilized electoral data from 1994, 1998, and 2002 Slovak parliamentary elections and socio-economic data of the population within Slovak regions which were eventually correlated with the voting results by party in the 79 Slovak districts. The results of this study demonstrate that there is a tendency among voters in certain regions to provide continuous support to the same political parties/movements over time. In addition, the socio-economic characteristics of the Slovak population (gender, age, education, religion, nationality, unemployment, work force distribution, wages, urban-rural variable, and population density) in different regions tend to influence voting preferences in the parliamentary elections. Finally, there is an evident correlation between party preference and the party’s position on integration into European Union, as measured by perceived attitudes regarding the benefits of EU membership.

Testing the Efficacy of Panax ginseng Extract as a Novel Anti-Quorum Sensing Agent

Quorum sensing (QS) is the phenomenon by which microorganisms regulate gene expression in response to cell-population density. These microorganisms synthesize and secrete small molecules known as autoinducers that increase in concentration as a function of cell density. Once the cell detects the minimal threshold concentration of an autoinducer, the gene expression is altered accordingly. Although the cellular circuitry responding to QS is relatively conserved, the cellular processes regulated by QS, for example are conjugation, motility, sporulation, biofilm formation and production of virulence factors importamt for infection. Since many pathogens have developed resistance to available antibiotics, novel therapies are required to further treat these pathogens. Inhibitors of QS are potential therapeutic candidates since they would inhibit virulence without selecting for antibiotic resistant strains. Previous studies have shown that the Chinese herb Panax ginseng contains compounds that inhibit QS activity. To further characterize this activity, a highly sensitive quantitative liquid assay was developed using a Chromobacterium violaceum AHL mutant, CV026 as a biomonitor strain. After confirmation that P. ginseng aqueous extracts had anti-QS activity, the extract was fractionated on a reverse phase C18 Sep Pak column. Most anti-QS activity was present in the flow through, and compounds eluted with ten percent acetonitrile in water antibacterial activity. We thus conclude that P. ginseng has anti-QS activity and the active compound is water soluble. Compounds from P. ginseng, could be used as a lead structure to design compound with higher anti-QS activity for therapeutic treatments.

Social and environmental regulation of signal plasticity and signal reliability in the electric fish Brachyhypopomus gauderio

The balance between the costs and benefits of conspicuous signals ensures that the expression of those signals is related to the quality of the bearer. Plastic signals could enable males to maximize conspicuous traits to impress mates and competitors, but reduce the expression of those traits to minimize signaling costs, potentially compromising the information conveyed by the signals. ^ I investigated the effect of signal enhancement on the information coded by the biphasic electric signal pulse of the gymnotiform fish Brachyhypopomus gauderio. Increases in population density drive males to enhance the amplitude of their signals. I found that signal amplitude enhancement improves the information about the signaler's size. Furthermore, I found that the elongation of the signal's second phase conveys information about androgen levels in both sexes, gonad size in males and estrogen levels in females. Androgens link the duration of the signal's second phase to other androgen-mediated traits making the signal an honest indicator of reproductive state and aggressive motivation. ^ Signal amplitude enhancement facilitates the assessment of the signaler's resource holding potential, important for male-male interactions, while signal duration provides information about aggressive motivation to same-sex competitors and reproductive state to the opposite sex. Moreover, I found that female signals also change in accordance to the social environment. Females also increase the amplitude of their signal when population density increases and elongate the duration of their signal's second phase when the sex ratio becomes female-biased. Indicating that some degree of sexual selection operates in females. ^ I studied whether male B. gauderio use signal plasticity to reduce the cost of reproductive signaling when energy is limited. Surprisingly, I found that food limitation promotes the investment in reproduction manifested as signal enhancement and elevated androgen levels. The short lifespan and single breeding season of B. gauderio diminishes the advantage of energy savings and gives priority to sustaining reproduction. I conclude that the electric signal of B. gauderio provides reliable information about the signaler, the quality of this information is reinforced rather than degraded with signal enhancement.^

A preliminary analysis of the correlation of food-web characteristics with hydrology and nutrient gradients in the southern Everglades

We estimated trophic position and carbon source for three consumers (Florida gar, Lepisosteus platyrhincus; eastern mosquitofish, Gambusia holbrooki; and riverine grass shrimp, Palaemonetes paludosus) from 20 sites representing gradients of productivity and hydrological disturbance in the southern Florida Everglades, U.S.A. We characterized gross primary productivity at each site using light/dark bottle incubation and stem density of emergent vascular plants. We also documented nutrient availability as total phosphorus (TP) in floc and periphyton, and the density of small fishes. Hydrological disturbance was characterized as the time since a site was last dried and the average number of days per year the sites were inundated for the previous 10 years. Food-web attributes were estimated in both the wet and dry seasons by analysis of δ15N (trophic position) and δ13C (food-web carbon source) from 702 samples of aquatic consumers. An index of carbon source was derived from a two-member mixing model with Seminole ramshorn snails (Planorbella duryi) as a basal grazing consumer and scuds (amphipods Hyallela azteca) as a basal detritivore. Snails yielded carbon isotopic values similar to green algae and diatoms, while carbon values of scuds were similar to bulk periphyton and floc; carbon isotopic values of cyanobacteria were enriched in C13compared to all consumers examined. A carbon source similar to scuds dominated at all but one study site, and though the relative contribution of scud-like and snail-like carbon sources was variable, there was no evidence that these contributions were a function of abiotic factors or season. Gar consistently displayed the highest estimated trophic position of the consumers studied, with mosquitofish feeding at a slightly lower level, and grass shrimp feeding at the lowest level. Trophic position was not correlated with any nutrient or productivity parameter, but did increase for grass shrimp and mosquitofish as the time following droughts increased. Trophic position of Florida gar was positively correlated with emergent plant stem density.

The Electoral Geography of the Slovak Republic: A Comparison of the 1994, 1998, and 2002 Parliamentary Elections

In what can rightly be said to be one of the most dramatic geopolitical shifts in modern times, the collapse of communist regimes in Central Europe and the former Soviet Union brought about dramatic changes in the entire region. As a consequence, wide ranging political, economic, and social transformations have occurred in almost all of these countries since 1989. The Slovak Republic, as a newly democratic country, went through the establishment of the electoral and party systems that are the central mechanisms to the formation of almost all modern democratic governments. The primary research purpose of this dissertation was to describe and explain regional variations in party support during Slovakia’s ten years of democratic transformation. A secondary purpose was to relate these spatial variations to the evolution of political parties in the post-independence period in light of the literature on transitional electoral systems. Research questions were analyzed using both aggregate and survey data. Specifically, the study utilized electoral data from 1994, 1998, and 2002 Slovak parliamentary elections and socio-economic data of the population within Slovak regions which were eventually correlated with the voting results by party in the 79 Slovak districts. The results of this study demonstrate that there is a tendency among voters in certain regions to provide continuous support to the same political parties/movements over time. In addition, the socio-economic characteristics of the Slovak population (gender, age, education, religion, nationality, unemployment, work force distribution, wages, urban-rural variable, and population density) in different regions tend to influence voting preferences in the parliamentary elections. Finally, there is an evident correlation between party preference and the party’s position on integration into European Union, as measured by perceived attitudes regarding the benefits of EU membership.

Understanding the Challenges of Expanding Community Forestry in Northwest Cameroon

The tropical afro-montane forest of the Northwest region is unique and under direct threat from the high population density of the region. Community-based forestry management is an opportunity to sustainably manage the remaining forest fragments. Community forestry was introduced to Cameroon with the legislation of the 1994 Forestry Law. Over two decades later little research has been conducted in the Northwest region of Cameroon. Twenty-four semi-structured interviews were conducted, and samples of forestry records were analyzed as exploratory research that would act as a base for further research. This research found that the tenure of the community over the community forest needed to be strengthened, marginalized populations needed to be empowered to participate, and governance needed to be improved both nationally, and locally. Further research will strengthen these conclusions and help Cameroon, and community forests around the world, be effectively established and managed.

Determination of Extracellular Molecules Produced by Vibrio Harveyi Using MS/MS

Quorum sensing (QS) is a process that allows bacteria to sense the population density of cells around them by communicating with each other via autoinducer molecules. This cross-communication is crucial in the regulation of bacterial processes such as bioluminescence, virulence, and biofilm formation. Previous research by Milburn and Makemson on Vibrio harveyi suggested that in addition of the known biosynthesis of three well-characterized autoinducers, dozens of unknown molecules are also produced and released to the environment by V. harveyi. This study was performed using electrospray tandem mass spectrometry with the purpose of detection and characterization of the extracellular molecules produced by V. harveyi, and assessment of their relationship to QS. A total of 11 molecules were characterized, from which three could be related to QS. These findings provide a glimpse of the nature of novel secondary metabolites produced by V. harveyi and provide the groundwork for further research.