5,874 research outputs found
The Vegetative Composition of a Beech-Maple Climax Forest in the Glaciated Plateau of Northeastern Ohio
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
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
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 . 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
Radiation effects on silver and zinc battery electrodes, III Interim report, Oct. 1965 - Jan. 1966
Radiation effects on silver-zinc battery electrode
Comstock Point, Lubec, Maine - A Natural and Photographic History
A natural and photographic history of our lands compiled by Lisa Dellwo and Bill Schlesinger, with the help of many friends and neighbors
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Rising CO2, Climate Change, and Public Health: Exploring the Links to Plant Biology
Background: Although the issue of anthropogenic climate forcing and public health is widely recognized, one fundamental aspect has remained underappreciated: the impact of climatic change on plant biology and the well-being of human systems. Objectives: We aimed to critically evaluate the extant and probable links between plant function and human health, drawing on the pertinent literature. Discussion: Here we provide a number of critical examples that range over various health concerns related to plant biology and climate change, including aerobiology, contact dermatitis, pharmacology, toxicology, and pesticide use. Conclusions: There are a number of clear links among climate change, plant biology, and public health that remain underappreciated by both plant scientists and health care providers. We demonstrate the importance of such links in our understanding of climate change impacts and provide a list of key questions that will help to integrate plant biology into the current paradigm regarding climate change and human health
Natural and managed soil structure: On the fragile scaffolding for soil functioning
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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