Origin and distribution of mineral species in limestone caves

More than 80 mineral species are known to result from secondary chemical reactions in solutional limestone caverns. These minerals are transitional and end-products of carbonate wall rock interactions with ground water and organic residue. Bacteria are often critical in fixing various ions in these reactions. Ultimate source of metallic ions is usually the sulphide minerals weathering in overlying strata, and brought to the cave environment by circulating ground waters. Hydrothermal solutions may bring heavy metallic ion concentrations from deeper strata. About one-third of the known cave mineral species occur in stalactitic form

An evolutionary approach to anomalous intuition

Intuition has always been associated with a hint of the anomalous, with credible examples of intuitive knowledge that appear to arise from the future or from distant locations without sensory mediation. Experimental and anecdotal evidence exists to suggest that a complete understanding of intuition will need to include these anomalous aspects of intuition. To that end it is important to recognize that an understanding of anomalous intuition, though presenting considerable challenges to physics and neuroscience, may not require ‘paranormal’ explanations or entities outside the compass of science. Anomalous intuition has traditionally been studied within the field of parapsychology where is it known as extrasensory perception (ESP). One model of ESP proposes two stages. In the first stage, the process, the anomalous information is ‘received’ and in the second stage, the product, the anomalous information is elaborated into conscious awareness and/or behaviour. The process is a challenge primarily for physics, and physicists both within parapsychology and in the mainstream are addressing it. The product, anomalous intuition, is grounded in normal psychological activity and is a problem for psychology and neuroscience to understand. In order to understand how ESP or anomalous intuition works, it is necessary to understand its purpose within an evolutionary context. Evolution has proven exceptionally effective in enabling species to make use of a wide range of physical phenomena for information gathering and communication. If some yet undiscovered physical process permits retrocausation would we not expect evolution to have capitalized on that process. As a product of evolution, ESP would have to conform to the requirements of evolutionary theory. Suddendorf and Corballis (2007) have elaborated the notion of mental time travel (MTT), the memory-based ability to project oneself into the past as well as the future, and have argued that the “ultimate evolutionary advantage” may lie in the capacity to envisage future events. Their model of MTT provides an ideal context in which to understand an evolutionary path for anomalous intuition. Working through the emotional system, anomalous intuition may operate by influencing the selection of memory images we use to execute our MTT. A growing body of data supports the involvement of the emotional system in anomalous intuition but there is only suggestive evidence for the expected hereditary component. The observed limited effectiveness of anomalous intuition may emerge from the balance achieved through an evolutionarily stable strategy, or result from inherent limitations in capitalizing on the underlying physical proces

Coupling of Length Scales and Atomistic Simulation of MEMS Resonators

We present simulations of the dynamic and temperature dependent behavior of Micro-Electro-Mechanical Systems (MEMS) by utilizing recently developed parallel codes which enable a coupling of length scales. The novel techniques used in this simulation accurately model the behavior of the mechanical components of MEMS down to the atomic scale. We study the vibrational behavior of one class of MEMS devices: micron-scale resonators made of silicon and quartz. The algorithmic and computational avenue applied here represents a significant departure from the usual finite element approach based on continuum elastic theory. The approach is to use an atomistic simulation in regions of significantly anharmonic forces and large surface area to volume ratios or where internal friction due to defects is anticipated. Peripheral regions of MEMS which are well-described by continuum elastic theory are simulated using finite elements for efficiency. Thus, in central regions of the device, the motion of millions of individual atoms is simulated, while the relatively large peripheral regions are modeled with finite elements. The two techniques run concurrently and mesh seamlessly, passing information back and forth. This coupling of length scales gives a natural domain decomposition, so that the code runs on multiprocessor workstations and supercomputers. We present novel simulations of the vibrational behavior of micron-scale silicon and quartz oscillators. Our results are contrasted with the predictions of continuum elastic theory as a function of size, and the failure of the continuum techniques is clear in the limit of small sizes. We also extract the Q value for the resonators and study the corresponding dissipative processes.Comment: 10 pages, 10 figures, to be published in the proceedings of DTM '99; LaTeX with spie.sty, bibtex with spiebib.bst and psfi

The implications of stakeholders' perceptions of land for sustainable land use management in NE Ghana

There are negative implications of changes in stakeholders traditional land perceptions for sustainable land use and management in north-east Ghana. In African tenurial systems, land use was based on a local mystical view of the environment and stakeholders broad-based knowledge of the local environments. These led to sustainable resource use and management. However, in the context of current political ecology of north-east Ghana as induced by increased population growth, urbanisation, the market economy, changes in religious beliefs, and government land policies, stakeholders understandings of land have acquired even greater importance in issues of sustainable land resource use and management. A mixed methodological approach, combining both qualitative and quantitative data gathering techniques for information on stakeholders land perceptions, was used to analyse their implications for sustainable land use and management. Changes in the dynamics of stakeholders perceptions of land are partly responsible for the current state of land and environmental degradation in north-east Ghana. Policies aimed at ensuring sustainable land use and environmental management must focus on those traditional land perceptions, which encourage environmental sustainabilit

Financial Feasibility of Simultaneous Production of Pine Sawlogs, Forage, and Meat Goats on Small Farms in Alabama: A Preliminary Analysis

Small and limited resource farmers and landowners in the Alabama Black Belt region face many challenges as they seek to make their farms and forestlands profitable, productive and environmentally sustainable. A host of problems—farmland conversion, urbanization pressures, reductions in water quality and availability, soil erosion, irregular cash flows, and increased government regulation—make managing family farms or forestland a difficult task. In response to these challenges, many farmers and landowners are considering agroforestry as an opportunity to increase land productivity and to improve their cash flows by combining income from agriculture, forestry, and animal production on the same piece of land. The objective in this paper was to conduct economic evaluations of agroforestry practices so that landowners, extension personnel, and other decision makers can correctly assess the potential of agroforestry practices among the many land-use options. The data analyzed were collected from a four year silvopastoral study conducted in the Black Belt region, on the property of the Federation of Southern Cooperatives in Epes, Alabama.Silvopasture, Financial Analysis, Enterprise Budgets, Cash Flow Analysis, Agribusiness, Community/Rural/Urban Development, Livestock Production/Industries, Production Economics, Productivity Analysis, Research Methods/ Statistical Methods,