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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.
221

A GIS-based inventory of terrestrial caves in West Central Florida: Implications on sensitivity, disturbance, ownership and management priority

Harley, Grant L 01 June 2007 (has links)
Active cave management, which represents any continuous action to conserve, restore, or protect a cave environment, is virtually non-existent in west-central Florida. This study focuses on developing an inventory to rank terrestrial caves in west-central Florida by management priority. A GIS-based cave inventory system, including a cave sensitivity index and cave disturbance index, were used as a tool to gain an understanding of the management priority of west-central Florida caves. The inventory was applied to 36 terrestrial caves in west-central Florida, which demonstrated a wide range of sensitivity and disturbance. The results show that by relying solely on sensitivity and disturbance scores, management priority may not be accurately determined. Further examination revealed that ownership and management status also affect management priority. Consequently, cave sensitivity, disturbance, ownership, or management status does not solely indicate management priority. Rather, the management priority of caves in west-central Florida depends on a number of complicated, interwoven factors, and the goal of management must be examined holistically. Each cave must be individually examined for its sensitivity, disturbance, resources, management, and social and physical context in order to gain an understanding of management priority. Nonetheless, the cave inventory system developed for this project was used to gain a general understanding of which caves hold management priority, based on the cave manager's objectives. In order to ensure the conservation and protection of west-central Florida terrestrial caves, support from county or state government, combined with cave inventory data, is crucial in developing sound management policy.
222

Filebos : En nyckel till Platons tankar omDet goda livet, belyst genom grottliknelsen?

Ringborg, Monika Margareta January 2015 (has links)
The purpose of this essay is to read Philebus based on three central themes – The Soul dialectic, the esoteric elements and some ethical problems, as well as to seek a comprehensive interpretation, rather than investigating, analyzing and interpreting individual concepts. Some questions that the essay aims to follow up are: 1) how can the dialogue on desire and rational knowledge highlighting Plato's ideas about the good life? 2) What are Plato’s real messages in the exposition of the good life? 3) Why are ethical questions related to esoteric elements of Plato's dialogues, and in general? The method is a reading between the lines; a hermeneutic interpretation process. Some patterns and contradictions were discovered during the reading, which shows an overall seemingly contradiction between ethics and metaphysics, but which with the the perspective of the dialectics be possible to reconcile. The final interpretation focuses on three concepts from Plato's own ranking of the good; beauty, proportion and truth. Together they constitute the good life in which pain plays an important role. Furthermore, it is possible to reach in Philebus about the good life, and the messages that one should always be true to oneself and to live modestly and always weigh reason to desire and choose wisdom. The ethical problems are both hidden in the shadows and elusive in Plato's dialogues, which can be a result of caution, but also a fear of losing oneself. Plato´s thinking is consistently dialectic, which is in this essay best illustrated by the allegory of the Cave.
223

Detailed structural analysis of detachment faulting near Colossal Cave, Southern Rincon Mountains, Pima County, Arizona

Krantz, Robert Warren January 1983 (has links)
No description available.
224

Technological strategies of stone tool production at Tabun Cave (Israel)

Dibble, Harold Lewis January 1981 (has links)
No description available.
225

The structuring of aquatic macroinvertebrate communities within cave streams

Watson, Troy Norton January 2010 (has links)
The unusual environmental conditions within caves provided unique opportunities for developing an understanding of ecosystem processes. However, relatively few studies have been conducted on the ecology of New Zealand cave systems. The primary aim of this research was to investigate changes in aquatic invertebrate communities along a longitudinal gradient from the surface into caves and investigate the fundamental drivers of cave communities. This study was carried out in three streams (two in pasture catchments and one in a forested catchment) flowing into caves in the Waitomo region, North Island, New Zealand. In order to address these aims I carried out a longitudinal survey of 12 sites in each stream, an experimental manipulation of food, and an isotopic study of a single stream. The longitudinal survey of the three cave streams revealed light intensity as well as algal and CPOM biomass all decreased significantly from outside the caves into caves. In contrast, water temperature, dissolved oxygen, stream width, depth, and velocity did not vary significantly with distance into caves. Benthic aquatic macroinvertebrate communities within the caves were a depauperate subset of surface communities, appearing to be structured by gradients in resources and colonisation through drift. However, some invertebrate taxa (primarily predators) were rarely found within caves, further suggesting that resource gradients were structuring cave communities. Surprisingly, the densities of some collector-browsers (primarily mayflies) increased within cave streams relative to surface densities. This may be due to a decrease in competition and predation, flexible feeding strategies, and high drift propensity. However, the benthic densities of most taxa within the caves appeared to be related to drift densities. Although surface forest and pastoral stream communities differed in community composition and density 32 meters within the caves invertebrate community diversity and density became similar, although specific taxa within communities varied. This convergence was attributed to similar environmental gradients within the caves. The resource addition experiment (adding leaf packs) indicated that cave streams were resource limited; the addition of leaves produced communities of similar richness and density across the environmental gradient. The isotopic survey suggested cave stream invertebrate communities were reliant upon similar basal resources to surface streams. However, within the cave epilithon appeared to be increasingly important while filamentous algae were absent. Cave aquatic invertebrates were also found to support terrestrial predators (spiders, harvestmen, and glow-worms), presumably increasing the abundance and diversity of terrestrial cave communities. In conclusion, aquatic cave communities were reliant upon surface derived resources and consequently strongly linked to surface land-use and managerial practices.
226

Field Test of a Calcite Dissolution Rate Law: Fort’s Funnel Cave, Mammoth Cave National Park

Slunder, J. Scott 01 December 1993 (has links)
The laboratory-derived calcite dissolution rate law of Plummer et al. (1978) is the most widely used and mechanistically detailed expression currently available for predicting dissolution rates as a function of water chemistry. Such rate expressions are of great use in understanding timescales associated with limestone karst development. Little work has gone into the field testing of the rate law under natural conditions. This work compared measured dissolution rates measured by a crystal weight loss experiment in Buffalo Creek within Fort’s Funnel Cave, which lies within a pristine, forested catchment of Mammoth Cave National Park. Continuous water chemistry sampling over the same period allowed a time-integrated prediction of the dissolution based on the Plummer et al (1978) expression. Results indicate that the rate law overpredicted dissolution by a factor of about ten. This concurs with earlier laboratory work suggesting that the law tends to overpredict rates in solutions close to equilibrium with respect to calcite, as were the waters in this study. Estimating dissolution rates with the expression under varying hydrologic conditions also allowed a prediction of storm scales change in cave forming processes. Neglecting effects of sediment masking on the bed, it was found that 78% of the work done in the dissolution of the cave passage during the study period occurred at or around baseflow conditions, with only a small amount during the effective but infrequent high flow conditions.
227

A Paleoethnobotanical Perspective on Late Classic Maya Cave Ritual at the Site of Pacbitun, Belize

Parker, Megan 12 August 2014 (has links)
This thesis presents the results of paleoethnobotanical investigations conducted at nine karst sites associated with the Maya site of Pacbitun in western Belize. The archaeobotanical remains were deposited during the Late Classic period and the site was abandoned at some point during this same time (c. A.D. 900). Paleoenvironmental data from the Maya Lowlands indicates that human activity contributed to regional climate change during the Late/Terminal Classic period. However, site-specific research has demonstrated a variety of responses to these social and ecological changes. The archaeobotanical data from this study is used as a proxy for understanding how people at Pacbitun ritually responded to macro-regional environmental stress. Ritual plant use at the cave sites does not conform to behavioral ecology models that predict biological, cost-fitness related responses to resource scarcity. Instead, the data supports a model of behavior based on culturally motivated ritual practices.
228

Looking at caves from the bottom-up: a visual and contextual analysis of four Paleolithic painted caves in southwest France (Dordogne)

Villeneuve, Suzanne Natascha 23 June 2010 (has links)
A century of hypotheses concerning Paleotlithic cave use has focused either on individual activities (such as vision quests or shamanistic visits) or group activities such as initiations. This thesis proposes and tests systematic criteria for assessing whether painted caves were locations of group or individual ritual activity in four caves in the Dordogne Region of Southwest France (Bernifal, Font-de-Gaume, Combarelles, and Villars). Resolving this issue provides an important foundation for examining more complex questions such as the exclusivity/inclusivity of groups using caves and their possible roles in the development and maintenance of inequalities in the Upper Paleolithic. Models for the emergence of socioeconomic complexity among hunters and gatherers have increasingly stressed the importance of ritual and ideology in understanding how inequality emerged. Addressing the issue of group dynamics and rituals associated with cave use may provide critical insight in our quest to understand Upper Paleolithic culture.
229

Draw Control in Block Caving Using Mixed Integer Linear Programming

David Rahal Unknown Date (has links)
Draw management is a critical part of the successful recovery of mineral reserves by cave mining. This thesis presents a draw control model that indirectly increases resource value by controlling production based on geotechnical constraints. The mixed integer linear programming (MILP) model is formulated as a goal programming model that includes seven general constraint types. These constraints model the mining system and drive the operation towards the dual strategic targets of total monthly production tonnage and cave shape. This approach increases value by ensuring that reserves are not lost due to poor draw practice. The model also allows any number of processing plants to feed from multiple sources (caves, stockpiles, and dumps). The ability to blend material allows the model to be included in strategic level studies that target corporate objectives while emphasising production control within each cave. There are three main production control constraints in the MILP. The first of these, the draw maturity rules, is designed to balance drawpoint production with cave propagation rates. The maturity rules are modelled using disjunctive constraints. The constraint regulates production based on drawpoint depletion. Drawpoint production increases from 100 mm/d to 404 mm/d once the drawpoint reaches 6.5% depletion. Draw can continue at this maximum rate until drawpoint ramp-down begins as 93.5% depletion. The maximum draw rate decreases to 100 mm/d at drawpoint closure in the three maturity rule systems included in the thesis. The maturity rule constraints combine with the minimum draw rate constraint to limit production based on the difference between the actual and ideal drawpoint depletion. Drawpoints which lag behind their ideal depletion are restricted by the maturity rules while those that exceeded the ideal depletion were forced to mine at their minimum rate to ensure that cave porosity was maintained. The third production control constraint, relative draw rate (RDR), prohibits isolated draw by ensuring that extraction is uniform across the cave. It does this by controlling the relative draw difference between adjacent drawpoints. It is apparent in this thesis that production from a drawpoint can have an indirect effect on remote drawpoints because the relative draw rate constraints pass from one neighbour to the next within the cave. Tightening the RDR constraint increases production variation during cave ramp-up. This variation occurs because the maturity rules dictate that new drawpoints must produce at a lower draw rate than mature drawpoints. As a result, newly opened drawpoints limit production from the mature drawpoints within their region of the cave (not just their immediate neighbours). The MILP is also used to quantify production changes caused by varying geotechnical constraints, limiting haulage capacity, and reversing mining direction. It has been shown that tightening the RDR constraint decreases total cave production. The ramp-up duration also increased by eighteen months compared to the control RDR scenario. Tighter relative draw also made it difficult to maintain cave shape during ramp-up. However, once ramp-up was complete, the tighter control produced a better depletion surface. The trial with limited haulage capacity identified bottlenecks in the materials handling system. The main bottlenecks occur in the production drives with the greatest tonnage associated with their drawpoints. There also appears to be an average haulage capacity threshold for the extraction drives of 2000 tonnes per drawpoint. Only one drive with a capacity below this threshold achieves its target production in each period. Reversing the cave advance to initiate in the South-East shows the greatest potential for achieving total production and cave shape targets. The greater number of drawpoints available early in the schedule provides more production capacity. This ability to distribute production over a greater number of drawpoints reduces the total production lag during ramp-up. In addition to its role in feasibility studies, the MILP is well suited for use as a production guidance tool. It has been shown in three case studies that the model can be used to evaluate production performance and to establish long term production targets. The first of the studies shows the analysis of historical production data by comparison to the MILP optimised schedule. The second shows that the model produces an optimised production plan irrespective of the current cave state. The final case study emulates the draw control cycle used by the Premier Diamond Mine. The series of optimised production schedules mirror that of the life-of-mine schedule generated at the start of the iterative process. The results illustrate how the MILP can be used by a draw control engineer to analyse production data and to develop long term production targets both before and after a cave is brought into full production.
230

Hydrodynamic imaging by blind Mexican cave fish

Windsor, Shane January 2008 (has links)
Whole document restricted until 2010, see Access Instructions file below for details of how to access the print copy. / Blind Mexican cave fish (Astyanax fasciatus) lack a functioning visual system, and are known to use self-generated water motion to sense their surroundings; an ability termed hydrodynamic imaging. Nearby objects distort the flow field created by the motion of the fish. These flow distortions are sensed by the mechanosensory lateral line. Little is known about the fluid mechanics involved in hydrodynamic imaging, or how the behaviour of the fish might influence their ability to sense the world around them. Automated image analysis was used to study the effects of swimming kinematics on the ability of the fish to sense their surroundings when introduced into a novel environment. The fish reacted to avoid head-on collisions with a wall at a remarkably short mean distance of 4.0 ± 0.2 mm. The ability of the fish to react, was dependent on whether they were beating their tail as they approached the wall. When following surfaces, such as a wall, the fish changed their swimming kinematics significantly and used both tactile and hydrodynamic information. Measuring the tendency of the fish to follow a tightening curve showed the fish to be moderately thigmotactic. The flow fields around freely swimming fish were experimentally measured using Particle Image Velocimetry (PIV). A new algorithm was developed to calculate the pressure field around the fish based on the velocity field measured using PIV. The algorithm was validated against analytical and computational fluid dynamic (CFD) solutions. The flow fields around gliding fish and the stimuli to the lateral line of the fish were calculated using CFD models, validated against the experimental PIV data. The flow fields changed in characteristic ways as the fish approached a wall head-on or swam parallel to a wall. At 0.10 body lengths from a wall, the stimulus to the lateral line was estimated to be sufficient for the fish to be able to detect the wall, but this decreased rapidly with increasing distance from the wall. The CFD models suggested that the velocity of the fish does not affect the distance at which they detect an object. Hydrodynamic imaging is a short range sensory ability and blind cave fish require their sensitive lateral line and fast reactions in order to be able to use it to sense the world around them and avoid collisions. The information gained about the fluid mechanics of hydrodynamic imaging, and the flow measurement and modelling techniques developed here will be useful for further study of this remarkable ability.

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