Brush control on sandy rangelands in central Alberta

Balsam poplar, aspen, and willows that had invaded subirrigated sandy rangeland were treated with (1) prescribed spring burning, (2) the herbicide 2,4-D ester, and (3) prescribed burning followed by 2,4-D ester. After 5 years, burning and spraying had reduced brush the most. Brush reinvasion was occurring rapidly on all treated areas. Stand openings of about one quarter hectare in an 8 meter high poplar forest resulting from these treatments did persist for at least 5 years. Treatments were effective enough to lower the forest cover and in some cases increase forage production. Repeated burning and spraying substantially reduced the density of reinvading woody suckers.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

FIXOR: A New Approach to Neutralizing Landmines and UXO

Canada’s MREL Specialty Explosive Products Limited introduces a new approach to neutralizing landmines and UXO

Statistical analysis of pump-pulse propagation in gas-filled capillaries for high-harmonic generation

Driving high-harmonic generation (HHG) with ultrashort pulses confined to gas-filled capillaries is an efficient method of generating extreme ultraviolet and x-ray radiation. In-situ pulse compression can significantly enhance HHG efficiency [1] but requires operation in the high-ionisation limit, leading to high sensitivity to initial conditions and causing the Gaussian driving pulse to break up into a train of subpulses as it propagates. Our previous studies [1,2] have focused on the most intense subpulse, which can be very short (<10 fs). Here, we perform statistical analysis of all pulse components predicted by numerical simulation, including the contribution of the weaker subpulses, with the aim of predicting generated HHG profiles

Disorder Induced Phase Transition in a Random Quantum Antiferromagnet

A two-dimensional Heisenberg model with random antiferromagnetic nearest-neighbor exchange is studied using quantum Monte Carlo techniques. As the strength of the randomness is increased, the system undergoes a transition from an antiferromagnetically ordered ground state to a gapless disordered state. The finite-size scaling of the staggered structure factor and susceptibility is consistent with a dynamic exponent $z = 2$.Comment: Revtex 3.0, 10 pages + 5 postscript figures available upon request, UCSBTH-94-1

Social and cultural origins of motivations to volunteer a comparison of university students in six countries

Although participation in volunteering and motivations to volunteer (MTV) have received substantial attention on the national level, particularly in the US, few studies have compared and explained these issues across cultural and political contexts. This study compares how two theoretical perspectives, social origins theory and signalling theory, explain variations in MTV across different countries. The study analyses responses from a sample of 5794 students from six countries representing distinct institutional contexts. The findings provide strong support for signalling theory but less so for social origins theory. The article concludes that volunteering is a personal decision and thus is influenced more at the individual level but is also impacted to some degree by macro-level societal forces