1,301 research outputs found
Risk programming analysis with imperfect information
A Monte Carlo procedure is used to demonstrate the dangers of basing (farm) risk programming on only a few states of nature and to study the impact of applying alternative risk programming methods. Two risk programming formulations are considered, namely mean-variance (E,V) programming and utility efficient (UE) programming. For the particular example of a Norwegian mixed livestock and crop farm, the programming solution is unstable with few states, although the cost of picking a sub-optimal plan declines with increases in number of states. Comparing the E,V results with the UE results shows that there were few discrepancies between the two and the differences which do occur are mainly trivial, thus both methods gave unreliable results in cases with small samples
Letter, 1926, April 13, from J.W. Richardson, C.A. Bezinque, and John Short to Officers and Members
1 page, Letter to Officers and Members of All Local Unions regarding Labor Da
- Pairing in Dense Neutron Matter: The Spectrum of Solutions
The - pairing model is generally considered to provide an
adequate description of the superfluid states of neutron matter at densities
some 2-3 times that of saturated symmetrical nuclear matter. The problem of
solving the system of BCS gap equations expressing the - model is
attacked with the aid of the separation approach. This method, developed
originally for quantitative study of S-wave pairing in the presence of strong
short-range repulsions, serves effectively to reduce the coupled, singular,
nonlinear BCS integral equations to a set of coupled algebraic equations. For
the first time, sufficient precision becomes accessible to resolve small energy
splittings between the different pairing states. Adopting a perturbative
strategy, we are able to identify and characterize the full repertoire of real
solutions of the - pairing model, in the limiting regime of small
tensor-coupling strength. The P-F channel coupling is seen to lift the striking
parametric degeneracies revealed by a earlier separation treatment of the pure,
uncoupled pairing problem. Remarkably, incisive and robust results are
obtained solely on the basis of analytic arguments. Unlike the traditional
Ginzburg-Landau approach, the analysis is not restricted to the immediate
vicinity of the critical temperature, but is equally reliable at zero
temperature. Interesting connections and contrasts are drawn between triplet
pairing in dense neutron matter and triplet pairing in liquid He.Comment: 23 pages, 1 figur
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