5,818 research outputs found
The Restructuring of the Saskatchewan Wheat Pool: Overconfidence and Agency
This paper examines how agency problems combined with overconfidence and hubris by coop management lead to financial failure in the Saskatchewan Wheat Pool. As a consequence of both of these problems, the Pool made poor investment decisions and ended up in severe financial difficulties. These problems were exacerbated by three additional factors: (1) ownership and control were separated via an A-B share structure, leading to a situation where neither farmer members nor investors had an incentive to monitor management activities; (2) the sheer volume of investment activity undertaken made it virtually impossible for the board to stay on top of what was happening; and (3) as a result of the change financial structure, senior management had available a large amount of debt capital that it could spend.Agribusiness, Crop Production/Industries,
The Goldstone solar system radar: A science instrument for planetary research
The Goldstone Solar System Radar (GSSR) station at NASA's Deep Space Communications Complex in California's Mojave Desert is described. A short chronological account of the GSSR's technical development and scientific discoveries is given. This is followed by a basic discussion of how information is derived from the radar echo and how the raw information can be used to increase understanding of the solar system. A moderately detailed description of the radar system is given, and the engineering performance of the radar is discussed. The operating characteristics of the Arcibo Observatory in Puerto Rico are briefly described and compared with those of the GSSR. Planned and in-process improvements to the existing radar, as well as the performance of a hypothetical 128-m diameter antenna radar station, are described. A comprehensive bibliography of referred scientific and engineering articles presenting results that depended on data gathered by the instrument is provided
Free-field Representations and Geometry of some Gepner models
The geometry of Gepner model, where is investigated by
free-field representation known as "bc\bet\gm"-system. Using this
representation it is shown directly that internal sector of the model is given
by Landau-Ginzburg -orbifold. Then we consider
the deformation of the orbifold by marginal anti-chiral-chiral operator.
Analyzing the holomorphic sector of the deformed space of states we show that
it has chiral de Rham complex structure of some toric manifold, where toric
dates are given by certain fermionic screening currents. It allows to relate
the Gepner model deformed by the marginal operator to the -model on CY
manifold realized as double cover of with ramification along
certain submanifold.Comment: LaTex, 14 pages, some acknowledgments adde
LESSONS LEARNT FROM A COMPARISON OF THREE ECOSYSTEM MODELS FOR PORT PHILLIP BAY, AUSTRALIA
Comparing multiple models applied to the same system can be highly instructive, both with regard to the system of interest and the models. In this case, three ecosystem simulation models (ECOSIM, Bay Model 2 [BM2] and the Integrated Generic Bay Ecosystem Model [IGBEM]) were tuned to data from Port Phillip Bay, Australia. ECOSIM is a dynamic biomass model; the other two are biogeochemical ecosystem models. Scenarios of environmental change (altered nutrient loading) and alternative fisheries management strategies (economically and ecologically motivated policies) are run for each model. A comparison of the predictions made by the models for these runs led to several general conclusions, first that large, shallow and enclosed bays, with many fish groups dependent on spawning stocks from outside the immediate area (e.g. Port Phillip Bay), may react more strongly to eutrophication than to fishing. The second conclusion is that a selected set of indicator groups (in this case, sharks, seagrass and chlorophyll a) seems to capture the major ecosystem impacts of alternative management scenarios. This has obvious implications for system monitoring in an adaptive management approach. The third is that multispecies or ecosystem models can identify potential impacts that a series of single-species models cannot (such as non-intuitive changes in biomass when species interactions outweigh fishery-induced pressures). Finally, policies focusing on the protection of species or groups only at higher trophic levels can fail to achieve sensible ecosystem objectives and may push systems into states that are far from pristine. These four findings have important ramifications for sustainable multiple-use management of shallow marine ecosystems. Afr. J. mar. Sci. 26: 219–24
The free energy in a class of quantum spin systems and interchange processes
We study a class of quantum spin systems in the mean-field setting of the
complete graph. For spin the model is the Heisenberg ferromagnet,
for general spin it has a probabilistic representation
as a cycle-weighted interchange process. We determine the free energy and the
critical temperature (recovering results by T\'oth and by Penrose when
). The critical temperature is shown to coincide (as a function of
) with that of the state classical Potts model, and the phase
transition is discontinuous when .Comment: 22 page
Classification of double flag varieties of complexity 0 and 1
A classification of double flag varieties of complexity 0 and 1 is obtained.
An application of this problem to decomposing tensor products of irreducible
representations of semisimple Lie groups is considered
Software Users Manual (SUM): Extended Testability Analysis (ETA) Tool
This software user manual describes the implementation and use the Extended Testability Analysis (ETA) Tool. The ETA Tool is a software program that augments the analysis and reporting capabilities of a commercial-off-the-shelf (COTS) testability analysis software package called the Testability Engineering And Maintenance System (TEAMS) Designer. An initial diagnostic assessment is performed by the TEAMS Designer software using a qualitative, directed-graph model of the system being analyzed. The ETA Tool utilizes system design information captured within the diagnostic model and testability analysis output from the TEAMS Designer software to create a series of six reports for various system engineering needs. The ETA Tool allows the user to perform additional studies on the testability analysis results by determining the detection sensitivity to the loss of certain sensors or tests. The ETA Tool was developed to support design and development of the NASA Ares I Crew Launch Vehicle. The diagnostic analysis provided by the ETA Tool was proven to be valuable system engineering output that provided consistency in the verification of system engineering requirements. This software user manual provides a description of each output report generated by the ETA Tool. The manual also describes the example diagnostic model and supporting documentation - also provided with the ETA Tool software release package - that were used to generate the reports presented in the manua
Poincar\'e and sl(2) algebras of order 3
In this paper we initiate a general classification for Lie algebras of order
3 and we give all Lie algebras of order 3 based on
and the Poincar\'e algebra in four-dimensions. We then
set the basis of the theory of the deformations (in the Gerstenhaber sense) and
contractions for Lie algebras of order 3.Comment: Title and presentation change
Remarks on the structure constants of the Verlinde algebra associated to
The structure constants of the Verlinde
algebra as functions of either vanish or can be expressed after a change
of variable as the weight function of an irreducible representation of .
We give a similar formula in the case.Comment: 5 pages, AmsTeX, 1 figure available on reques
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