A Plan of Farm Organization for Hill Land Farms in Southeastern Ohio

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Environmental boundary conditions for the origin of life converge to an organo-sulfur metabolism

Published in final edited form as: Nat Ecol Evol. 2019 December ; 3(12): 1715–1724. doi:10.1038/s41559-019-1018-8.It has been suggested that a deep memory of early life is hidden in the architecture of metabolic networks, whose reactions could have been catalyzed by small molecules or minerals before genetically encoded enzymes. A major challenge in unravelling these early steps is assessing the plausibility of a connected, thermodynamically consistent proto-metabolism under different geochemical conditions, which are still surrounded by high uncertainty. Here we combine network-based algorithms with physico-chemical constraints on chemical reaction networks to systematically show how different combinations of parameters (temperature, pH, redox potential and availability of molecular precursors) could have affected the evolution of a proto-metabolism. Our analysis of possible trajectories indicates that a subset of boundary conditions converges to an organo-sulfur-based proto-metabolic network fuelled by a thioester- and redox-driven variant of the reductive tricarboxylic acid cycle that is capable of producing lipids and keto acids. Surprisingly, environmental sources of fixed nitrogen and low-potential electron donors are not necessary for the earliest phases of biochemical evolution. We use one of these networks to build a steady-state dynamical metabolic model of a protocell, and find that different combinations of carbon sources and electron donors can support the continuous production of a minimal ancient 'biomass' composed of putative early biopolymers and fatty acids.80NSSC17K0295 - Intramural NASA; 80NSSC17K0296 - Intramural NASA; T32 GM100842 - NIGMS NIH HHSAccepted manuscrip

Non-imprisonment conditions on spacetime

The non-imprisonment conditions on spacetimes are studied. It is proved that the non-partial imprisonment property implies the distinction property. Moreover, it is proved that feeble distinction, a property which stays between weak distinction and causality, implies non-total imprisonment. As a result the non-imprisonment conditions can be included in the causal ladder of spacetimes. Finally, totally imprisoned causal curves are studied in detail, and results concerning the existence and properties of minimal invariant sets are obtained.Comment: 12 pages, 2 figures. v2: improved results on totally imprisoned curves, a figure changed, some misprints fixe

Remnants of an ancient metabolism without phosphate

Phosphate is essential for all living systems, serving as a building block of genetic and metabolic machinery. However, it is unclear how phosphate could have assumed these central roles on primordial Earth, given its poor geochemical accessibility. We used systems biology approaches to explore the alternative hypothesis that a protometabolism could have emerged prior to the incorporation of phosphate. Surprisingly, we identified a cryptic phosphate-independent core metabolism producible from simple prebiotic compounds. This network is predicted to support the biosynthesis of a broad category of key biomolecules. Its enrichment for enzymes utilizing iron-sulfur clusters, and the fact that thermodynamic bottlenecks are more readily overcome by thioester rather than phosphate couplings, suggest that this network may constitute a "metabolic fossil" of an early phosphate-free nonenzymatic biochemistry. Our results corroborate and expand previous proposals that a putative thioester-based metabolism could have predated the incorporation of phosphate and an RNA-based genetic system. PAPERCLIP

The Form and Style of Gnomic Hypermetrics

Gnomic poems have often been noted for their unusual metrical style. One aspect of their style that stands out is the hypermetric usage, both because these poems contain a notably high incidence of hypermetric verses and because the verses are frequently categorized as irregular. This paper analyses hypermetric composition in Maxims I, Maxims II, and Solomon and Saturn in detail to illustrate the major stylistic features of gnomic composition. It demonstrates that, contrary to the conclusions of some previous scholars, the hypermetric verses basically follow the form for hypermetric composition that can be found in most conservative poems, but with the inherent flexibility of hypermetric metre pushed to a greater extent than in most narrative poems, making for lines that are longer, heavier, and more complex. This alternate style highlights the importance of each individual aphorism and characterizes the solemnity of the poems as a whole. By composing their poems in accordance with the trends of this specialized style, poets may have been marking their composition as separate from narrative poems and encouraging their audience to consider each individual poem in the larger context of Old English wisdom poetry

EFFECTS OF PERENNIAL FORAGE COMPOSITION AND HARVEST INTENSITY ON THE WEED SEEDBANK COMMUNITY

Most arable weeds arise from a resident soil seedbank and are typically controlled with tillage and herbicides, each of which pose sustainability challenges to growers and consumers. However, agronomic management practices that reduce weed seed input to the seedbank and that accelerate mortality of seeds already in the soil could reduce the need for more conventional weed control. Previous research and farmer practice has demonstrated that rotation of annual crops with several years of perennial forage can reduce weed abundance and the need for chemical weed control. In perennial forage systems, crop species and harvest intensity may have important effects on seedbank composition due to the multiple stress and mortality factors these systems impose on weeds, including facilitation of strong crop-weed competitive interactions, periodic defoliation of crop (and weed) canopies, and potentially crop species-specific associations with soil faunal and microbial communities that cause seed damage and mortality. Unfortunately, we know little about the influence of agronomic practices such as forage crop species selection or harvest frequency and harvest height on weed population dynamics or the specific mechanisms that regulate weed seed survival in the soil in perennial forage systems. We used a three-year factorial field experiment established in 2018 that included four mixtures of perennial forage legumes, each grown with orchardgrass, Dactylis glomerata L., two harvest height treatments (5 and 10 cm residual forage height), and two harvest frequency treatments (three and five harvests per year) to investigate how perennial forage composition and management act as community assembly filters on the composition and abundance of the weed seedbank. The composition and abundance of the weed seedbank was quantified at the end of the third year of the study using the direct germination method in a heated greenhouse. While overall seedbank density did not differ across treatments, seedbank community composition was influenced by the interactive effects of both harvest height and harvest frequency. More intensely harvested plots (shorter stubble remaining) favored weed seed bank communities more heavily dominated by weed species with specific functional traits: mat-forming weeds that set seed close to the soil surface were favored in short stubble harvest regimes, possibly due to their ability to grow and reproduce while evading defoliation. Conversely, the harvest regime in less intensely harvested plots enabled a more generalist weed community. In order to determine whether weed seed decay mechanisms might vary across the treatments, we conducted a weed seed burial experiment with seeds of a common weed, velvetleaf (Abutilon theophrasti Medik.). Seeds were buried in each experimental unit to simulate seed shed and incorporation in the soil and were extracted in the following spring. Seed death over the burial period was not different in more intensely harvested plots compared to less intensely harvested plots. This suggests that when considering how forage canopy management practices mediate seed mortality, seed decay may be of lesser importance compared to other mechanisms of seedbank decline such as fatal germination and seed predation. An indicator plant material was buried to gain a secondary measurement of cellulose decay in the system without the complex effects of seed dormancy and viability. In red clover and white clover biculture plots, cellulose decay was greater in more frequent harvest treatments when compared to less frequent. Lastly, both the decay of velvetleaf seeds and of indicator cellulose were significant predictors of seedbank community composition, demonstrating that microbial activity acts as a biological filter on weed seedbank community assembly

Poetic Style and Innovation in Old English, Old Norse, and Old Saxon

This book traces the development of hypermetric verse in Old English and compares it to the cognate traditions of Old Norse and Old Saxon. The study illustrates the inherent flexibility of the hypermetric line and shows how poets were able to manipulate this flexibility in different contexts for different practical and rhetorical purposes. This analysis shows what degree of control the poets had over the traditional alliterative line, what effects they were able to produce with various stylistic choices, and how attention to poetic style aids literary analysis.https://scholarworks.wmich.edu/mip_rrc/1004/thumbnail.jp

Sensitivity of a high‐elevation rocky mountain watershed to altered climate and CO2

We explored the hydrologic and ecological responses of a headwater mountain catchment, Loch Vale watershed, to climate change and doubling of atmospheric CO2 scenarios using the Regional Hydro‐Ecological Simulation System (RHESSys). A slight (2°C) cooling, comparable to conditions observed over the past 40 years, led to greater snowpack and slightly less runoff, evaporation, transpiration, and plant productivity. An increase of 2°C yielded the opposite response, but model output for an increase of 4°C showed dramatic changes in timing of hydrologic responses. The snowpack was reduced by 50%, and runoff and soil water increased and occurred 4–5 weeks earlier with 4°C warming. Alpine tundra photosynthetic rates responded more to warmer and wetter conditions than subalpine forest, but subalpine forest showed a greater response to doubling of atmospheric CO2 than tundra. Even though water use efficiency increased with the double CO2 scenario, this had little effect on basin‐wide runoff because the catchment is largely unvegetated. Changes in winter and spring climate conditions were more important to hydrologic and vegetation dynamics than changes that occurred during summer

Reestablishing the Juneberry on the Fort Berthold Indian Reservation: Cultural, horticultural, and educational connections

Tribal people of the Northern Great Plains have utilized plants for centuries. Amelanchier anifolia (Juneberries/Serviceberries) historically played an important part in the diet and culture of the Mandan, Hidatsa, and Arikara (MHA) Tribal Nations. Research conducted as part of this study into historical and contemporary uses of the Juneberry by MHA Tribal Members indicated extensive historical use and a high interest in Juneberry reestablishment for cultural, nutritional, and economic reasons. Previous research on Juneberries has investigated factors including state of dormancy, propagation method, transplant type, and mulch type. Another purpose of this study was to elucidate the impact of presence of water, cultivar type, soil type and site on the transplant success rate of Juneberries on the arid Northern Great Plains. Alternating experimental units of Amelanchier anifolia cultivars (Honeywood, Smokey, and Martin) were planted with and without presence of water on three selected sites within the Fort Berthold Reservation. Precipitation levels and plant vigor were monitored. Soil type, and cultivar differences were insignificant, however, presence of water results indicate its necessity. A plantbased curriculum framework was presented to improve cultural relevancy for students at Tribal Colleges