A study of the energy content of the seismic waves P and pP

The energy observed in the seismic waves P and pP in a large number of earthquakes is compared, by means of two partly independent methods, with the theoretical energy calculated from a standard equation. The results are analyzed, depth of focus, distance from epicenter to observing station, geographical location of epicenter, and azimuth from station being used as variables. When compared with the theoretical ratio, the ratio of the energy in pP to the energy in P averaged over a distance range 60°-90° is observed to decrease with depth, by 0.5 on a logarithmic scale of energy between 100 and 600 km. depth of focus. The results for the two waves are compared separately with theoretical values, and the observed effect appears to be about equally due to an increase of P energy and a decrease of pP energy with depth. The theoretical formula is reëxamined to determine if permissible changes in the assumptions or numerical values can account for the results. No such changes are found; certain assumptions with respect to increased absorption of energy near the surface of the earth provide a partial qualitative explanation, but quantitatively they cannot be reconciled with data from other sources. The variation with distance between observed and calculated energies is not large enough to be treated quantitatively; slight changes in the slope of the accepted velocity vs. depth curve are tentatively suggested on the basis of it. The energy ratio pP/P compared to the theoretical ratio is significantly too large in shallow earthquakes occurring in the Aleutian region and can be attributed to pP rather than P. For shallow shocks in the New Hebrides region and very deep shocks of the Southwest Pacific there is some indication that the energy ratio is smaller than for comparable shocks elsewhere. Data on observed wave periods are given. The effect of differences between instruments is considered

Genetic and evolutionary consequences of harvest in American ginseng, Panax quinquefolius L. (Araliaceae)

American ginseng (Panax quinquefolius L.) is a wild-harvested perennial plant of the eastern deciduous forest. Harvest supplies world markets with roots used in Asian medicine, but this practice is fatal to plants. The objective of this research was to investigate the genetic and evolutionary consequences of harvest. As seen in animal species, harvest may alter size selection by preferentially removing large individuals. Chapter 2 describes my study of harvest\u27s effects on size selection. From the simulated harvests, I observed that large-sized plants lose their fitness advantages in harvested populations. Harvest pressure could ultimately lead to population divergence if selected traits are genetically-based. As described in Chapter 3, I collected size, reproductive and age data from plants in 12 wild populations. I then used the proportion of seedlings and juvenile plants as a \u27harvest index\u27, which was based on the recovery of an experimentally-harvested population. In most study years, the age-size relationship varied with harvest index. In a separate common garden study, I also found that size differences were maintained among populations 3 to 4 years after transplantation, suggesting genetically-based variation. Harvest also reduces genetic diversity, which may lead to increased levels of inbreeding in affected populations. At the same time, unusual levels of outcrossing are possible because of \u27restocking\u27 with cultivated seeds. Chapter 4 describes the controlled crosses that I conducted to evaluate the effects of inbreeding and outcrossing with cultivated plants. The smaller size of seedlings produced from self-pollination relative to those from cross-pollination suggested inbreeding depression, but cultivated genotypes may confer accelerated growth not observed in the wild. As described in Chapter 5, I also examined the importance of genetic diversity to population growth rate. Eighteen populations were censused to obtain demographic data and their genetic diversity was assessed using neutral DNA markers (RAPD). Because of the descriptive nature of the data, I used path analysis to model and test for relationships among genetic diversity, population size and harvest pressure, and how these in turn affect population growth rate. From the results of the path analysis, harvest pressure had a negative influence on population growth, whereas genetic diversity contributed positively to population growth rates. Altogether, harvest may have far-reaching, unintended effects for populations of P. quinquefolius in the wild

CONTRACTING FOR SOIL CARBON CREDITS: DESIGN AND COSTS OF MEASUREMENT AND MONITORING

Many firms anticipate that a cap on greenhouse gas emissions will eventually be imposed, either through an international agreement like the Kyoto protocol or through domestic policy, and have started to take voluntary actions to reduce their emissions. If agricultural producers participate in the emerging market for tradable C-credits, it must be possible to verify that actions farmers take do increase the amount of C in soils and this increase can be maintained over the length of the contract. In this paper we develop a prototype measurement and monitoring scheme for C-credits sequestered in agricultural soils and estimate its costs for the small grain-producing region of Montana using an econometric-process simulation model. Three key results emerge from the prototype framework. First, the efficiency of measurement and monitoring procedures for agricultural soil C sequestration depends on the price of C credits. Second, we find that at all price levels, costs of measuring and monitoring are largest in areas that exhibit the greatest heterogeneity in carbon values. Third, in a case study application of our prototype measurement and monitoring scheme, we find that if we assume similar error and confidence levels as forestry contracts, the upper estimate of measurement and monitoring costs associated with a contract that pays farmers per tonne of C sequestered is 3% of the value of a C-credit. This cost is small relative to the estimated net value of the contract. Thus we conclude that measurement and monitoring costs are not likely to be large enough to prevent producers from participating in a market for tradable credits.Environmental Economics and Policy,

Sub-pixel spatial resolution wavefront phase imaging

A phase imaging method for an optical wavefront acquires a plurality of phase images of the optical wavefront using a phase imager. Each phase image is unique and is shifted with respect to another of the phase images by a known/controlled amount that is less than the size of the phase imager's pixels. The phase images are then combined to generate a single high-spatial resolution phase image of the optical wavefront

Ecosystem physiology responses to global change

Journal ArticleMost ecosystems exposed to double ambient C02 show higher peak season net carbon uptake than those growing at current-ambient C02. For grasslands, above-ground biomass increased by an average of 14%, although individual responses for a given system and year range from negative to +85%. The wide range of the biomass response shows the highly interactive nature of the C02 response with other environmental factors, including water and nutrient availability, and temperature. For instance, low-temperature dominated systems, such as alpine grassland, Arctic tundra, and cool climate coniferous forest trees, are among the least responsive to elevated C02 , showing in some instances no growth response and complete acclimation of peak season gas exchange after a few years

ECONOMICS OF AGRICULTURAL SOIL CARBON SEQUESTRATION IN THE NORTHERN PLAINS

Under the Kyoto protocol of the United Nations Framework Convention on Climate Change the United States is charged with reducing emissions of greenhouse gases to seven percent below their 1990 levels by the period 2008-2012. These reductions could be met from many industries including agriculture. In this paper, an economic simulation model is linked to an ecosystem model to quantify the economic efficiency of policies that might be used to sequester carbon (C) in agricultural soils in the Northern Plains region. Simulations with the Century ecosystem model show that long-term soil C levels associated with a crop/fallow system are less than those for grass alone, but that soil C levels for grass-clover-pasture are greater than for continuously cropped grains. The analysis shows that a CRP-style policy is found to be an inefficient means to increase soil C because the per acre payments to convert crop-land to grass-only draw land from both the crop/fallow system and the continuous cropping system, and costs typically exceed $100 per MT (metric ton) of C. In contrast, payments to adopt continuous cropping were found to produce increases in soil C for between$5 to $70 depending on area and degree of targeting of the payments. The most efficient, lowest cost policy is achieved when payments are targeted to land that was previously in a crop/fallow rotation. In this range, soil C sequestration appears to be competitive with C sequestered from other sources.policy design, economic efficiency, soil carbon, sequestration, valuing soil carbon, Great Plains agriculture, Resource /Energy Economics and Policy, Q2,

Archaeological Survey and Assessment of the Proposed Eno River and Little Lick Creek Force Main Routes, Durham County, North Carolina

Technical Report No. 20, Research Laboratories of Archaeology, University of North Carolina at Chapel Hill. Reports in this series present the findings of archaeological surveys and test excavations completed by the RLA between 1983 and present

ECONOMICS OF AGRICULTURAL SOIL CARBON SEQUESTRATION IN THE NORTHERN GREAT PLAINS

Under the Kyoto protocol of the United Nations Framework Convention on Climate Change the United States is charged with reducing emissions of greenhouse gases to seven percent below their 1990 levels by the period 2008-2012. These reductions could be met from many industries including agriculture. In this paper, an economic simulation model is linked to the CENTURY ecosystem model to quantify the economic efficiency of policies that might be used to sequester carbon (C) in agricultural soils in the Northern Great Plains region. Model outputs are combined to assess the costs of inducing changes in equilibrium levels of soil C through three types of policies. The first is a CRP-style policy that provides producers with per-acre payments for converting crop-land to permanent grass; the second is a policy that provides per-acre payments to all farmers that use continuous cropping, regardless of the land's cropping history; the third is a policy that provides per-acre payments for the use of continuous cropping only on land units that had previously been in a crop/fallow rotation. The analysis shows that a CRP-style policy is found to be an inefficient means to increase soil C resulting in costs that typically exceed $100 per MT (metric ton) of C. In contrast, payments to adopt continuous cropping were found to produce increases in soil C for between$5 to $70/MT depending on the geographic area and degree of targeting of the payments. The most efficient, lowest cost policy is achieved when payments are targeted to land that was previously in a crop/fallow rotation. In this range, soil C sequestration appears to be competitive with C sequestered from other sources.policy design, economic efficiency, soil carbon, sequestration, valuing soil carbon, Great Plains agriculture, Environmental Economics and Policy, Q2,

Appraising and enhancing a leadership in innovation model

Innovation is a significant contributor to effective economies worldwide. This paper aims to apprise a model of Innovation and Leadership created by Grant Mooney and Ken Dovey (Mooney & Dovey 2008). The model examines the resource of individual creativity and organisational innovation through the use of constructs and metrics. Recent developments have identified constructs that were used to appraise and enhance the model as a result of the strong correlations identified in literature and their high level of relevance. The new factors are (1) 'followership' or confidence in top leadership, and (2) 'return on investment' which measures the innovation efforts in an organisation