2,014 research outputs found
Nutrient deficiencies affecting peanut production in soils of northeast Thailand
Peanut is widely grown in the rainy season on upland soils (mostly Paleustults) in northeast Thailand. The nutrient status of these soils for peanut production has not been adequately assessed. Response to phosphorus, potassium, sulfur, and copper on a range of soil types of this region have been obtained in pot trials using pasture legumes (Wilaipon 1976). The present experiments were set up to identify nutrient deficiencies which could limit yield and kernel quality of peanut on an Oxic Paleustult (Khorat series)
A Finitely Convergent Duality Theory for Zero-One Integer Programming
Given an integer programming problem, a constructive procedure is presented for generating a finite sequence of increasingly stronger dual problems to the given problem. The last dual problem in the sequence yields an optimal solution to the given integer programming problem. It is shown that this dual problem approximates the convex hull of the feasible integer solutions in a neighborhood of the optimal solution it finds. The theory is applicable to any bounded integer programming problem with rational data
Nuclear Reactor Refueling Optimization
In a 1971 paper, Suzuki and Kiyose give a model for light water moderated atomic reactor refueling optimization. Specifically, they present a linear programming formulation for minimizing the number of fresh fuel assemblies required by a reactor over a finite planning horizon subject to power generation and safety requirements and reactor design specifications. The optimal refueling policies found by Suzuki and Kiyose were useful in reducing the fresh fuel required, but two difficulties were encountered. First, the optimal linear programming solutions included small fractional numbers of fresh fuel assemblies which were difficult to round off. The second difficulty was that their formulation had approximately 165H constraints where H is the length of the planning horizon. The problems solved had H=10, but it was desired to analyze the problem for longer planning horizons of 20 to 30 stages without solving prohibitively large mathematical programming problems.
In this paper, we give a reformulation of the reactor refueling optimization problem that consists of approximately 15H constraints and a large number of columns. This reformulation is required because the state-of-the-art of integer programming does not usually permit the solution of integer programs with thousands or even many hundreds of constraints. Moreover, the reformulation should permit the linear programming approximation to be more easily solved, at least approximately. Finally, the reformulation identifies and analyzes explicitly the fundamental activity in refueling optimization; namely, the introduction, degradation and removal of fuel assemblies. This should make it easier to modify the model to take into account additional features of the problem such as a cost for moving an assembly from one location to another
Staying in the science stream: patterns of participation in A-level science subjects in the UK.
This paper describes patterns of participation and attainment in A-level physics, chemistry and biology from 1961 to 2009. The A-level has long been seen as an important gateway qualification for higher level study, particularly in the sciences. This long term overview examines how recruitment to these three subjects has changed in the context of numerous policies and initiatives that seek to retain more young people in the sciences. The results show that recruitment to the pure sciences has stagnated, general trends have hardly varied and the track record of government policy in influencing change is not strong. There is no evidence for increasing achievement gaps between the sexes at A-level and even national policy requiring that all young people study science up to the age of 16 appears to have had little impact on recruitment at this leve
Optimal States for Bell inequality Violations using Quadrature Phase Homodyne Measurements
We identify what ideal correlated photon number states are to required to
maximize the discrepancy between local realism and quantum mechanics when a
quadrature homodyne phase measurement is used. Various Bell inequality tests
are considered.Comment: 6 pages, 5 Figure
Non-local Realistic Theories and the Scope of the Bell Theorem
According to a widespread view, the Bell theorem establishes the untenability
of so-called 'local realism'. On the basis of this view, recent proposals by
Leggett, Zeilinger and others have been developed according to which it can be
proved that even some non-local realistic theories have to be ruled out. As a
consequence, within this view the Bell theorem allows one to establish that no
reasonable form of realism, be it local or non-local, can be made compatible
with the (experimentally tested) predictions of quantum mechanics. In the
present paper it is argued that the Bell theorem has demonstrably nothing to do
with the 'realism' as defined by these authors and that, as a consequence,
their conclusions about the foundational significance of the Bell theorem are
unjustified.Comment: Forthcoming in Foundations of Physic
Qubits from Number States and Bell Inequalities for Number Measurements
Bell inequalities for number measurements are derived via the observation
that the bits of the number indexing a number state are proper qubits.
Violations of these inequalities are obtained from the output state of the
nondegenerate optical parametric amplifier.Comment: revtex4, 7 pages, v2: results identical but extended presentation,
v3: published versio
Characterization of Binary Constraint System Games
We consider a class of nonlocal games that are related to binary constraint
systems (BCSs) in a manner similar to the games implicit in the work of Mermin
[N.D. Mermin, "Simple unified form for the major no-hidden-variables theorems,"
Phys. Rev. Lett., 65(27):3373-3376, 1990], but generalized to n binary
variables and m constraints. We show that, whenever there is a perfect
entangled protocol for such a game, there exists a set of binary observables
with commutations and products similar to those exhibited by Mermin. We also
show how to derive upper bounds strictly below 1 for the the maximum entangled
success probability of some BCS games. These results are partial progress
towards a larger project to determine the computational complexity of deciding
whether a given instance of a BCS game admits a perfect entangled strategy or
not.Comment: Revised version corrects an error in the previous version of the
proof of Theorem 1 that arises in the case of POVM measurement
Does quantum nonlocality irremediably conflict with Special Relativity?
We reconsider the problem of the compatibility of quantum nonlocality and the
requests for a relativistically invariant theoretical scheme. We begin by
discussing a recent important paper by T. Norsen [arXiv:0808.2178] on this
problem and we enlarge our considerations to give a general picture of the
conceptually relevant issue to which this paper is devoted.Comment: 18 pages, 1 figur
Two qubits of a W state violate Bell's inequality beyond Cirel'son's bound
It is shown that the correlations between two qubits selected from a trio
prepared in a W state violate the Clauser-Horne-Shimony-Holt inequality more
than the correlations between two qubits in any quantum state. Such a violation
beyond Cirel'son's bound is smaller than the one achieved by two qubits
selected from a trio in a Greenberger-Horne-Zeilinger state [A. Cabello, Phys.
Rev. Lett. 88, 060403 (2002)]. However, it has the advantage that all local
observers can know from their own measurements whether their qubits belongs or
not to the selected pair.Comment: REVTeX4, 5 page
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