17,001 research outputs found
Centralizers of maximal regular subgroups in simple Lie groups and relative congruence classes of representations
In the paper we present a new, uniform and comprehensive description of
centralizers of the maximal regular subgroups in compact simple Lie groups of
all types and ranks. The centralizer is either a direct product of finite
cyclic groups, a continuous group of rank 1, or a product, not necessarily
direct, of a continuous group of rank 1 with a finite cyclic group. Explicit
formulas for the action of such centralizers on irreducible representations of
the simple Lie algebras are given.Comment: 27 page
A Survey of Literature on Genetically Modified Crops: Economics, Ethics and Society
This paper reports on a review of literature in the form of academic papers and published research on ethical and consumer issues for GM crops in North America, with particular emphasis on GM wheat. The issues raised in these papers and the findings and arguments posed by the authors are outlined. A general conclusion that can be drawn from this overview is that public attitudes toward GM foods are diverse and sometimes quite strongly held. The strong negative views of GM food held by some appear to be mainly grounded in individuals’ ethical or moral values. Ethical and risk assessment issues have not been fully explored in the existing literature. There is a general consensus in the applied economics literature that GM crops result in economic benefits, although benefits to individual consumers may not be great enough to overcome perceived risk. Carefully planned provision of credible information informing members of the public of benefits and related issues of concern or costs associated with agricultural biotechnology may have benefits for farm and industry groups, but maintenance of trust in information sources and content is vital to credibility. The discovery and use of genomic techniques that express explicit consumer benefits may lead to more favourable attitudes by many consumers.Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies, I00, Q16, Q18,
Strongly interacting bosons in a disordered optical lattice
Disorder, prevalent in nature, is intimately involved in such spectacular
effects as the fractional quantum Hall effect and vortex pinning in type-II
superconductors. Understanding the role of disorder is therefore of fundamental
interest to materials research and condensed matter physics. Universal
behavior, such as Anderson localization, in disordered non-interacting systems
is well understood. But, the effects of disorder combined with strong
interactions remains an outstanding challenge to theory. Here, we
experimentally probe a paradigm for disordered, strongly-correlated bosonic
systems-the disordered Bose-Hubbard (DBH) model-using a Bose-Einstein
condensate (BEC) of ultra-cold atoms trapped in a completely characterized
disordered optical lattice. We determine that disorder suppresses condensate
fraction for superfluid (SF) or coexisting SF and Mott insulator (MI) phases by
independently varying the disorder strength and the ratio of tunneling to
interaction energy. In the future, these results can constrain theories of the
DBH model and be extended to study disorder for strongly-correlated fermionic
particles.Comment: 15 pages, 4 figures updated to correct errors in referencing previous
wor
Small-X Quarks at HERA Predict the Ultra High Energy Neutrino-Nucleon Cross Section
New structure function data at small Bjorken from HERA are used along
with next-to-leading order QCD evolution to predict a cross section for
charged-current interactions of ultrahigh energy neutrinos with nucleons. This
new result is over twice the size of previous estimates and has important
implications for cosmic ray experiments now underway as well as for KM3 arrays
(cubic kilometer-scale neutrino telescopes) now in the planning stages.Comment: KITCS94-9-1, 9 pages (REVTeX) plus 3 postscript figures all uuencode
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