Document formatted into pages; contains 78 pages. / Title from PDF of title page. / Thesis (M.S.P.H.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Malathion is a commonly used organophosphate pesticide on field crops, fruits, nut trees, vegetables, livestock, agricultural premises, and land. The approved uses also include mosquito and medfly control. These uses can result in human skin contact. The purpose of this study is to evaluate the human skin absorption of malathion for the purpose of assessing the risks associated with aqueous solution exposures following applications. Aerial applications can result in solubilized malathion in swimming pools and other waters that may be contacted. Human volunteers were selected and exposed to aqueous solutions of malathion at various concentrations. Participants submerged their arms and hands in twenty liters of dilute malathion solution in either a stagnant or stirred environment. The "disappearance method" was applied by measuring malathion concentrations in the water before and after human subject exposure to the water for various periods of time. Malathion was measured using Gas Chromatography. No measurable skin absorption was detected in 42% of the participants. Measurable skin absorption among the remaining 58% of participants resulted in doses that were more than an order of magnitude less than the minimal dose necessary to cause a measurable change in red blood cell acetylcholinesterase (RBC-AChE). Extrapolation of these results to a mathematical model for recreational swimmers and bathers exposed to contaminated swimming pools and surface waters typically detected after bait application again are an order of magnitude below the doses needed to cause a detectable change in RBC-AChE. These data indicate that exposure to aqueous malathion following usual aerial bait applications is not appreciably absorbed, and therefore, it is not a public health hazard. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

The Local News Pool or “LNP” as it’s referred to concerns competing television news stations within a single market forming a cooperative partnership in order to share content such as video and interviews. This study used depth interviews with assignment editors, producers, and photographers in Austin, Texas, Tampa, Florida, and Denver, Colorado, and incorporated a quantitative content analysis of news stories assigned to the LNP in Austin to discover how this convergence model operates, its effects on workers, and the potential for homogenization. This study discovered that by incorporating this convergence model into a newsroom and categorizing certain stories as “shared” it altered the level of importance photographers and producers placed on the story. By these journalists having prior knowledge that the competition might use or have an interest in a certain story, it altered the value placed on it to one of something “extra” or “filler” and not highly desired for the news broadcast. In addition, this study provides an updated look at the multilayer gatekeeping process by incorporating competing organizations within this decision making process. This study found gatekeepers cooperate on stories each find would produce similar content if their station were to send their own crews. The aspect of competition becomes present when gatekeepers request stories not intended for the LNP such as breaking news. The level of cooperation is often based on ratings and perception of one’s willingness to reciprocate if needed. / text

Management of groundwater as a common pool resource relies heavily on an institutional design that is fitted to the aquifers to be managed and is scaled to provide efficient and effective governance. Texas has committed to a decentralized system of groundwater management through Groundwater Conservation Districts (GCDs) that offers a high level of local control and area-specific adaptability. However, increasing pressures on the state’s groundwater resources coupled with a strong local aversion to outsider interference has resulted in a proliferation of small single-county GCDs that are neither well fitted to the aquifer systems nor sufficiently scaled to be efficient or effective. In recognition of these challenges, the persistent response has been a slow transition towards larger-scale management. Although a full transition to centralization via state control is not likely to be politically feasible, it would also be limited in its effectiveness, recognizing the wide diversity of climate conditions, water use patterns, growth projections, and aquifer characteristics that exist across the state. Regionalization is offered as a policy proposal for an institutional arrangement and scale of groundwater governance that provides a balance between centralization and decentralization, using institutions that are better fitted to the aquifer systems and appropriately scaled to provide sufficient funding and resources. The merits and logic of regionalized groundwater management have been recognized as demonstrated by the establishment of the joint regional-planning process within aquifer-based Groundwater Management Areas (GMAs), using GCD representatives as the de facto regional groundwater planners. However, the new unfunded mandates for which the already underfunded GCDs are now responsible and the extraordinary planning process complexity that has developed may prove to be unworkable. This realization compels consideration of management through regional authorities designed using the ready-made framework of the GMAs and principles gleaned from successful models of regionalization from other states and within Texas. Such regional authorities, if provided with sufficient resources and authority, would respect the logic of fit and scale and would be better equipped to address the current and future groundwater management challenges in Texas. / text

One chemoautotrophic origin of life theory posits the abiotic formation of alkyl thiols as an initial step to forming biomolecules and eventually a simple chemoautotrophic cell. The premise of this theory is that a recurring reaction on the charged surfaces of pyrite served as a primordial metabolism analogous to the reductive acetyl-CoA pathway (Wächtershäuser 1988) that was later enveloped by a primitive cellular membrane. Alkyl thiols have not previously been identified in terrestrial hot springs as unequivocally abiogenic, but they have been produced in the laboratory under hydrothermal conditions in the presence of a catalyst. I analyzed the dissolved gas content of several hot springs and conducted sterile laboratory experiments in order to evaluate the abiogenic formation of methanethiol (CH3SH), the simplest of the alkyl thiols. Specifically of interest was Cinder Pool, an acid-sulfate-chloride hot spring in Yellowstone National Park. This spring is unusual in that it contains a subaqueous molten sulfur layer (~18 m depth) and thousands of iron- vii sulfur-spherules floating on the surface, which are created by gas bubbling through the molten floor of the spring. This material could potentially serve as a reactive and catalytic surface for abiogenic CH3SH formation in Cinder Pool. Gas samples were collected from Cinder Pool and an adjacent hydrothermal feature in fall of 2011 using the bubble strip method. Two samples contained measurable quantities of CH3SH and other organic sulfur gases, with concentrations of all gases generally higher at the bottom of the pool. Laboratory microcosm experiments were conducted to replicate these findings in a sterile environment. Analog Cinder Pool water was injected into serum bottles containing different iron-sulfur compounds, including cinders collected from the pool itself, as catalytic surfaces for the CH3SH generating reaction. The bottles were then charged with hydrogen (H2), carbon dioxide (CO2), and carbon disulfide (CS2) as reaction gases and incubated for a week at temperatures between 60 and 100oC. Bottles used either powdered FeS, FeS2 (pyrite) or cinder material as a catalytic surface, and all of these surfaces were capable of catalyzing CH3SH formation. In bottles without imposed CS2, however, cinder material was the only surface that produced any detectable CH3SH. While CH3SH is central to the autotroph-first theory and has been synthesized in the laboratory (e.g. Heinen and Lauwers 1996), it has not previously been observed to form abiotically in natural systems. I have identified CH3SH in a natural hydrothermal feature where it is unlikely to have formed secondary to microbial activity, and I have duplicated these field findings in sterile laboratory experiments using the cinders as a reactive surface for formation. / text

It is recognised by society that freshwater resources play a major role in economic development and in maintaining life supporting ecosystems services. Transboundary river basins cover about 45% of the earth’s land surface and their governance is therefore of critical importance. Transboundary freshwater resources are considered a common-pool resource. Collective action is therefore needed in order to supply both public and private goods from these resources but is yet in short supply. This thesis intends to analyse a complementary framework to the common Integrated Water Resources Management (IWRM) approach with the objective of enhancing investments in collective action to address this dilemma. Results indicate that transboundary water resources management in itself can be identified as a regional public good. The results also indicate that IWRM has been promoted as a standard management concept; often without first having identified and agreed the objectives of the intended multiple uses of water. Outcomes related to IWRM at the transboundary scale are therefore difficult to identify and evidence points towards continued water quality degradation at a global scale and development opportunities not achieved. Two different tools for how to assess the generation of benefits from cooperation are presented in this thesis including an institutional assessment framework adapted to transboundary institutions. Together these steps make up an outcome-driven approach that clarifies the value of water in all management and development stages. Through such an outcome-driven approach, water issues can provide the incentives necessary in order to identify cooperative paths and thus become important factors in negotiations to establish effective regional governance regimes. This would take the broader political, economic and geographical context into consideration thus supporting a process towards more integration of interests between countries.

published_or_final_version / Zoology / Master / Master of Philosophy

The goal of this dissertation is to advance the theory of common-pool resources in three different but interrelated ways: (1) Common-pool resources theory has identified a number of factors that play an important role on human groups' ability to engage in successful institutional change. However it is still not clear which are their causal relationships on specific contexts. This study looks at the relationship between two of the aforementioned factors: local leadership and local autonomy. It does so in the context of the decentralization of the governance of protected areas for biodiversity conservation in Costa Rica. (2) Historically, common-pool resources theory has paid limited attention to the interactions between local institutions and higher levels of governance. This study incorporates the analysis of cross-scale institutional linkages into the assessment of decentralization reforms in Costa Rica. (3) To do so it incorporates an analytical approach that allows for systematic and rigorous comparisons of small-to-moderate-sized Ns and is apt at handling multiple-causality outcomes. Looking at these issues in the context of the decentralization of biodiversity governance in Costa Rica is relevant because it is the most biodiverse country per unit of area in the world, and during the last twenty years has experimented with decentralization policies to create locally-based institutions for biodiversity conservation. Among my most relevant findings are: (1) that the presence of local leadership is positively related to institutions ability to gain local autonomy from the central government. (2) However, in the context of a class-based society with a strong urban-rural divide, the emergence of local leadership for conservation in rural settings is likely not able to take place by itself without support from within the bureaucratic structure. (3) More diverse are better than less diverse sets of cross-scale linkages in local institutions' ability to gain and maintain local autonomy overtime. (4) Local autonomy can help local institutions increase their potential for biodiversity conservation as long as there are well-defined institutional arrangements in place. Otherwise, local institutions might find themselves pursuing other agendas that might have an unclear relation with biodiversity conservation.

Temporary snowmelt pool ecosystems in southwestern Quebec were examined with special emphasis on identifying the macrofauna and determining their spatial distribution, as well as ascertaining temporal changes in community composition. 68 taxa were collected from ten snowmelt pools. Major taxa represented were Diptera, Coleoptera, Hemiptera, Trichoptera, Odonata, Ephemeroptera, Anostraca, Isopoda, Amphipoda, Gastropoda and Bivalvia; the insects dominated the communities and the Culicidae (Diptera) was the most abundant taxon collected. The fauna were unevenly distributed both spatially and temporally amongst the pools. The occurrence of taxa was similar in pools in the same geographic location. The habitat characteristics of each pool, coupled with their proximity to a permanent waterbody and their accessibility to organisms, perhaps influenced the distribution of the various taxa. A successional pattern was observed in which filter-feeders and detritivores appeared first, followed by predators. After drought, a similar pattern was seen in pools that were replenished by summer rains, but taxon diversity was lower. In addition, pools with longer hydroperiods harboured more taxa than shorter-lived pools.

Since boiling heat transfer affords a very effective means to transfer heat, it is implemented in numerous technologies and industries ranging from large power generation plants to micro-electronic thermal management. Although having been a subject of research for several decades, an accurate prediction of boiling heat transfer is still challenging due to the complexity of the coupled mechanisms involved. It appears that the boiling heat transfer coefficient is intimately related to bubble dynamics (i.e. bubble nucleation, growth and detachment) as well as factors such as nucleation site density and interaction between neighbouring and successive bubbles. In order to contribute to the understanding of the boiling phenomenon, an experimental investigation of saturated pool boiling from a single or two neighbouring artificial nucleation sites on a polished copper surface has been performed. The bubble growth dynamics has been characterized for different wall superheats and a experimental growth law has been established. The interaction between successive bubbles from the same nucleation site has been studied, showing the bubble shape oscillations that can be caused by these interactions. The forces acting on a growing bubble has been reviewed, and a complete momentum balance has been made for all stages of bubble growth. The curvature along the interface has been measured, and indications concerning the mechanism of bubble detachment have been suggested. The rise of bubble after detachment has been investigated, and the maximum velocity reached before a change of direction has been estimated and compared to existing models from the literature. The interaction between bubbles growing side by side has been studied: the generation and propagation of a wave front during the coalescence of two bubbles has been highlighted. As boiling heat transfer enhancement techniques are being imagined and developed, this study also focuses on the electrohydrodynamic enhancement technique. Boiling experiments have been performed in the presence of electric fields, and their effects on heat transfer and bubble dynamics have been characterized. Although the volume of the bubbles at detachment and the relationship between the bubble frequency and the wall superheat were not affected, the bubble growth curve was modified. The bubbles were elongated in the direction of the electric field, and this elongation was estimated and compared to other studies from the literature. The rising velocity of the bubble was reduced in the presence of electric field, and the behaviour of bubbles growing side by side was modified, the electric field causing the bubbles to repeal each other. These results, obtained in a fully controlled environment, provide compelling evidence that electric fields can be implemented to alter the bubble dynamics and subsequently heat transfer rates during boiling of dielectric fluids.

Šiame darbe pateikiama Merkio baseino geografinė analizė, apžvelgiamas teritorijos kultūrinis potencialas, nurodomi vandens turizmui tinkami maršrutai. Gal būt skaitytoją sudomins krištolinės Merkio versmės ir kils noras pakeliauti po žilą senovę menančią Dainavos šalį... / Tourism becoming more and more popular, increasing chances to travel have inspired to analyse one type of active tourism – water tourism. The Merkys river pool is one of the best suitable places for environment, great cultural heritage and dietary peculiarities of the rivers. The Merkys and its affluents – the Visinčia, the Grūda, the Šalčia, the Ūla, the Varėnė are some of the most beautiful and cleanest rivers in Lithuania. Picturesque country – side pineries, steep slopes, banks, deep pools, sandy coastlines and many well – equipped camping places make the Merkys attractive for tourists. This work covers a detailed gydrological anglysis of the Merkys river pool, provides segments of privers suitable for water tourism, describes prominent sightseeing places. The Merkys river pool is in the southeast of Lithuania. The Merkys river system includes 810 rivers and serams of different sizes whose total lenght is 2413km. There are 175 lakes of different size, occupying 39,7km2. Their bigger part is in the Dzūkija Eminence. Privers and pouds make up the base of hydrographic net in the other part of the Merkys river pool. Woodlands take up about 50% of the territory: 4 natural reserves, the national park of Dzūkija and 28 reservations of different purposes. The Merky‘s pool is one of the oldest living places in Lithuania. People living for a long time in the territory created and ledt many material and spiritual values which make up our large cultural urbanized. The majority... [to full text]