5,896 research outputs found

    Fraunhofer line discriminator Final report

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    Airborne Fraunhofer line discriminato

    The Vegetative Composition of a Beech-Maple Climax Forest in the Glaciated Plateau of Northeastern Ohio

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    Author Institution: Department of Biological Sciences, University School, Shaker Heights, OhioSurvey was made of a beech-maple forest by the quarter point method during August, 1968. The forest is located on a mesic, level upland of the glaciated Allegheny Plateau in eastern Cuyahoga County, Ohio, in the Chagrin River drainage basin. Geologically the upland is underlain by Mississippian formations capped by a thin cover of till, in which soils of the Ellsworth soil catenathe Rittman and Wadsworth silt loamsare developed. The dominant plant species in this forest are American beech and sugar maple, which together comprise 68% of the trees recorded and have a total combined importance value of 62%. Red oak, red maple, and cucumbertree are important secondary dominants, but white ash and tuliptree are of little significance in the woodland composition. A greater overall abundance of secondary-associate mixed-mesophytic species than is normally found in such forests occurs. This composition supports the concept of a poly climax beechmaple association and is suggested to be a result of past selective lumbering and a variation in topography and soils. Although there is some evidence of past selective lumbering, the forest appears to be in an essentially undisturbed, virgin state. It has been partially destroyed as the forest is now part of a tract of land developed as a new secondary school campus

    Schlesinger transformations for elliptic isomonodromic deformations

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    Schlesinger transformations are discrete monodromy preserving symmetry transformations of the classical Schlesinger system. Generalizing well-known results from the Riemann sphere we construct these transformations for isomonodromic deformations on genus one Riemann surfaces. Their action on the system's tau-function is computed and we obtain an explicit expression for the ratio of the old and the transformed tau-function.Comment: 19 pages, LaTeX2

    The Boson peak in supercooled water

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    We perform extensive molecular dynamics simulations of the TIP4P/2005 model of water to investigate the origin of the Boson peak reported in experiments on supercooled water in nanoconfined pores, and in hydration water around proteins. We find that the onset of the Boson peak in supercooled bulk water coincides with the crossover to a predominantly low-density-like liquid below the Widom line TWT_W. The frequency and onset temperature of the Boson peak in our simulations of bulk water agree well with the results from experiments on nanoconfined water. Our results suggest that the Boson peak in water is not an exclusive effect of confinement. We further find that, similar to other glass-forming liquids, the vibrational modes corresponding to the Boson peak are spatially extended and are related to transverse phonons found in the parent crystal, here ice Ih.Comment: 25 pages, 9 figure

    Comstock Point, Lubec, Maine - A Natural and Photographic History

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    A natural and photographic history of our lands compiled by Lisa Dellwo and Bill Schlesinger, with the help of many friends and neighbors

    Natural and managed soil structure: On the fragile scaffolding for soil functioning

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    Soil structure in natural systems is a product of complex interactions between biological activity, climate and soil minerals that promote aggregation and accumulation of biopores. In arable lands, the management of soil structure often requires the mechanical fragmentation of hardened soil to improve seedbed, control weeds and bury plant residue. Despite difficulties in defining and quantifying soil structure, its critical role is evidenced by loss of productivity when natural structure is perturbed (e.g. compaction) and the long history of tillage in agriculture. To overcome persistent ambiguities among scientific disciplines regarding definition and function of soil structure, we propose a framework for distinguishing managed and natural soil structure based on their different formation processes and functions. Natural soil structure preserves ecological order and legacy that promotes biopore reuse, stabilizes foodwebs and protects soil organic carbon (SOC). The contribution of net primary productivity of natural lands to soil structure forming processes makes it a useful (surrogate) metric of soil structure. The benefits of managed soil structure for crops are quantified indirectly via comparisons with no-till farming under similar conditions. The levels and trends of SOC are useful metrics for the status of natural and managed soil structure. The systematic consideration of soil structure state in natural and arable lands using suitable metrics is a prerequisite for rational decisions related to land management and ensuring sustainable functioning of a fragile and central resource such as soil
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