How the Dimension of Space Affects the Products of Pre-Biotic Evolution: The Spatial Population Dynamics of Structural Complexity and The Emergence of Membranes

We show that autocatalytic networks of epsilon-machines and their population dynamics differ substantially between spatial (geographically distributed) and nonspatial (panmixia) populations. Generally, regions of spacetime-invariant autocatalytic networks---or domains---emerge in geographically distributed populations. These are separated by functional membranes of complementary epsilon-machines that actively translate between the domains and are responsible for their growth and stability. We analyze both spatial and nonspatial populations, determining the algebraic properties of the autocatalytic networks that allow for space to affect the dynamics and so generate autocatalytic domains and membranes. In addition, we analyze populations of intermediate spatial architecture, delineating the thresholds at which spatial memory (information storage) begins to determine the character of the emergent auto-catalytic organization.Comment: 9 pages, 7 figures, 2 tables; http://cse.ucdavis.edu/~cmg/compmech/pubs/ss.ht

The application of metrics to industrial prototyping processes: An empirical study

A key problem in the development of information systems is understanding features of the development process. To this end, in recent years, considerable interest has been focused on modelling processes. In this paper, the results of an empirical investigation into the use of prototyping in information systems development is described. Nine prototyping processes across eight different sites of varying size were analysed and data relating to each process collected. The notation of Role Activity Diagrams (RADs) was used to capture each of the nine processes. Analysis of the interactions in each process revealed that the project manager interacted with the prototyper far more often in large developments than in small or medium-sized developments. However, significantly more interactions between the project manager and end-user were found in small-sized developments than for any other sized site. The study demonstrates how measures of business models can aid analysis of the process rather than the product and highlights the need for more empirical investigation into this and other facets of the development process. A number of lessons have been learnt from our analysis; these we also explain

Issues Related to Incorporating Northern Peatlands into Global Climate Models

Northern peatlands cover ~3–4 million km2 (~10% of the land north of 45°N) and contain ~200–400 Pg carbon (~10–20% of total global soil carbon), almost entirely as peat (organic soil). Recent developments in global climate models have included incorporation of the terrestrial carbon cycle and representation of several terrestrial ecosystem types and processes in their land surface modules. Peatlands share many general properties with upland, mineral-soil ecosystems, and general ecosystem carbon, water, and energy cycle functions (productivity, decomposition, water infiltration, evapotranspiration, runoff, latent, sensible, and ground heat fluxes). However, northern peatlands also have several unique characteristics that will require some rethinking or revising of land surface algorithms in global climate models. Here we review some of these characteristics, deep organic soils, a significant fraction of bryophyte vegetation, shallow water tables, spatial heterogeneity, anaerobic biogeochemistry, and disturbance regimes, in the context of incorporating them into global climate models. With the incorporation of peatlands, global climate models will be able to simulate the fate of northern peatland carbon under climate change, and estimate the magnitude and strength of any climate system feedbacks associated with the dynamics of this large carbon pool

The impact of a northern peatland on the earth’s radiative budget: sustained methane emission versus sustained carbon sequestration

Northern peatlands sequester carbon and emit methane, and thus have both cooling and warming impacts on the climate system through their influence on atmospheric burdens of CO2 and CH4. These competing impacts are usually compared by the global warming potential (GWP) methodology, which determines the equivalent CO2 annual emission that would have the same integrated radiative forcing impact over a chosen time horizon as the annual CH4 emission. We use a simple model of CH4 and CO2 pools in the atmosphere to extend this analysis to quantify the dynamics, over years to millennia, of the net radiative forcing impact of a peatland that continuously emits CH4 and sequesters C. We find that for observed ratios of CH4 emission to C sequestration (roughly .01-2 mol mol-1), the radiative forcing impact of a northern peatland begins, at peatland formation, as a net warming that peaks after about 50 years, remains a diminishing net warming for the next several hundred to several thousand years, depending on the rate of C sequestration, and thereafter is or will be an ever increasing net cooling impact. We then use the model to evaluate the radiative forcing impact of various changes in CH4 and/or CO2 emissions. In all cases, the impact of a change in CH4 emissions dominates the radiative forcing impact in the first few decades, and then the impact of the change in CO2 emissions slowly exerts its influence

Economic Potential of Using High Tunnel Hoop Houses to Produce Fruits and Vegetables

Abstract Hoop house plasticulture has been promoted as a production technology that allows fruit and vegetable crops to be grown in the cool season months in early spring and late fall. At this time little information regarding the economics of hoop house plasticulture is available. Two fruit and vegetable production systems were developed for growing conditions in south-central Oklahoma. The first system has a spinach crop followed by field tomato, and the second system has annually produced strawberry followed by yellow and zucchini squash. Crop production data were collected in a three-year randomized and replicated experiment. The objectives were (1) to determine the expected cost of production for each crop and systems, (2) to determine the breakeven price for each crop in each system, and (3) to determine how robust breakeven prices are to a number of yield, expense and marketing scenarios. The expected total cost of production were $1,968 and$1,652 per house for spinach and tomato crops, respectively, and $2,749,$359 and $353 per house for yellow and zucchini squash crops, respectively. Breakeven prices for spinach and tomato were$3.32 and $0.83 per pound, respectively, and$6.16, $0.92, and$1.40 per pound for strawberry and yellow and zucchini squash, respectively. Breakeven prices for spinach and strawberry crops were most sensitive to assumptions about quantity of marketable yield sold and/or quantity of yield consumed by grower household.breakeven prices, economics, fruits and vegetables, hoop houses, plasticulture, Agribusiness, Farm Management, Labor and Human Capital, Marketing, Production Economics,

Global Quantum Correlation in the Ising model

We study quantum correlations in an isotropic Ising ring under the effects of a transverse magnetic field. After characterizing the behavior of two-spin quantum correlations, we extend our analysis to global properties of the ring, using a figure of merit for quantum correlations that shows enough sensitivity to reveal the drastic changes in the properties of the system at criticality. This opens up the possibility to relate statistical properties of quantum many-body systems to suitably tailored measures of quantum correlations that capture features going far beyond standard quantum entanglement.Comment: Published in the International Journal of Quantum Information as part of the special issue devoted to "Quantum Correlations: entanglement and beyond

The importance of northern peatlands in global carbon systems during the Holocene

We applied an inverse model to simulate global carbon (C) cycle dynamics during the Holocene period using atmospheric carbon dioxide (CO2) concentrations reconstructed from Antarctic ice cores and prescribed C accumulation rates of Northern Peatlands (NP) as inputs. Previous studies indicated that different sources could contribute to the 20 parts per million by volume (ppmv) atmospheric CO2 increase over the past 8000 years. These sources of C include terrestrial release of 40–200 petagram C (PgC, 1 petagram=1015 gram), deep oceanic adjustment to a 500 PgC terrestrial biomass buildup early in this interglacial period, and anthropogenic land-use and land-cover changes of unknown magnitudes. Our study shows that the prescribed peatland C accumulation significantly modifies our previous understanding of Holocene C cycle dynamics. If the buildup of the NP is considered, the terrestrial pool becomes the C sink of about 160–280 PgC over the past 8000 years, and the only C source for the terrestrial and atmospheric C increases is presumably from the deep ocean due to calcium carbonate compensation. Future studies need to be conducted to constrain the basal times and growth rates of the NP C accumulation in the Holocene. These research endeavors are challenging because they need a dynamically-coupled peatland simulator to be constrained with the initiation time and reconstructed C reservoir of the NP. Our results also suggest that the huge reservoir of deep ocean C explains the major variability of the glacial-interglacial C cycle dynamics without considering the anthropogenic C perturbation