The Multiplicity of K X-Rays Emitted in (6-Li,xn) Reactions

This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

The Decay Modes of High-Spin Compound Nuclei Produced in 6-Li-Induced Fusion Reactions

This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

Scattering of 99-MeV 6-Li Ions

This work was supported by National Science Foundation Grant PHY 75-00289 and Indiana Universit

Phenomenological and Microscopic Optical-Model Descriptions of 99 MeV 6-Li Scattering

This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

Understory plant composition and nitrogen transformations resistant to changes in seasonal precipitation

Abstract Climate change has increased global mean surface temperatures and altered hydrological processes, and projections suggest that these changes will accelerate. As seasonal precipitation patterns change, so will the soil resources available for plants. In the midwestern United States, winter temperatures and precipitation are expected to increase, while snowfall is expected to be reduced. Reduced snowpack could lead to greater frost damage and alter the timing and amount of plant available resources at the start of the growing season. In the summer, precipitation is expected to decrease, and variability is expected to increase, creating longer and more frequent dry periods. In temperate forests, herbaceous understory plants and woody plants in early developmental stages are expected to be highly sensitive to changes in abiotic conditions. Here, we study how seasonal changes in precipitation affect the timing and availability of resources in a temperate deciduous forest. Further, we examine how changes in abiotic conditions influence understory composition and woody plant recruitment. We established a fully factorial experiment that manipulated winter snowfall and summer precipitation to create wet, dry, and control (ambient) conditions in a temperate deciduous forest near West Lafayette, Indiana, USA. We found that large changes in winter and summer precipitation appeared to affect forest processes independently of one another, and changes in seasonal precipitation altered understory composition minimally and had little to no effect on mineralization rates. The recruitment of woody plant species may be more sensitive to altered precipitation, as snow removal lowered germination rates and wet summer conditions lowered relative growth of a woody plant species, Lindera benzoin. In general, though, ecological processes in this forest understory were relatively resistant to change, at least in the short timeframe of this experiment

Optical potential for <SUP>6</SUP>Li+<SUP>28</SUP>Si elastic scattering at 154 MeV

The differential cross section angular distribution for 6Li elastic scattering from 28Si was measured at 154 MeV lab energy for center-of-mass angles up to 66&#176;. The data exhibit forward-angle diffractive structure and a large-angle falloff similar to that of refractive nuclear scattering. An optical-model analysis with Woods-Saxon form factors and standard fitting criterion yields a broad continuum of admissible real central potential depths |V|~120-200 MeV rather than the multitude of discrete parameter families encountered at lower bombarding energies. The best fit to the data selects a |V| near 160 MeV. A Woods-Saxon squared form factor as well as a microscopic folding-model potential have also been investigated in fitting the data

Native Seedling Colonization on Stockpiled Mine Soils Is Constrained by Site Conditions and Competition with Exotic Species

Sites disturbed through mining practices can be challenging to restore with native vegetation, as the path of ecological succession is often unknown and hard to predict. We conducted an establishment study that explored restoration strategies to increase native vegetation on a newly formed stockpile of soil at New Gold&rsquo;s New Afton Mine in British Columbia, Canada. Establishment of native species in semi-arid grasslands is often constrained by seed and seedling microsite limitations, so treatments were imposed to assist in reducing these limitations. We established a fully factorial design with a native seed treatment (seeded and unseeded) and four soil preparations: raking, hydroseed slurry, a combination of raking and hydroseed slurry, and no preparation. Raking assisted in increasing total seedling establishment, regardless of whether the site was seeded or not. Raking and seeding increased the number of native seedlings and resulted in the greatest species richness, suggesting that native seedling establishment is primarily seed-limited, but that microclimate is also important for the establishment of some native seeds. We found that exotic species were able to capitalize on the disturbance and outcompeted the native species, but reducing seed-limitations by sowing more native seeds and increasing available microclimates by raking or tilling may increase native species&rsquo; success at the establishment phase

The Optical Potential for 99 MeV 6-Li Scattering

This work was supported by National Science Foundation Grant PHY 76-84033 and Indiana Universit

Multiplicity of K X rays emitted in (<SUP>6</SUP>Li,Xn) reactions

Measurement of x-ray-x-ray and x-ray-&#947;-ray coincidence yields indicates that two to three K x rays are emitted, on the average, during the deexcitation of neutron-poor Tl and Pb isotopes populated by (6Li,xn) reactions. Experimental constraints suggest that approximately two x rays arise from a narrow region of spin (12&#8804;J&#8804;20) dominated by low-energy M1 transitions. Measurement of the singles yield as well as the mean multiplicity of the K x rays provides a useful new method for determining absolute evaporation-residue cross sections