55,930 research outputs found

    The Restructuring of the Saskatchewan Wheat Pool: Overconfidence and Agency

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    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,

    EFFECTS OF ASPIRATION VERSUS NEUROTOXIC LESIONS OF THE AMYGDALA ON EMOTIONAL RESPONSES IN MONKEYS

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    All previous reports describing alterations in emotional reactivity after amygdala damage in monkeys were based on aspiration or radiofrequency lesions which likely disrupted fibers of passage coursing to and from adjacent ventral and medial temporal cortical areas. To determine whether this associated indirect damage was responsible for some or all of the changes described earlier, we compared the changes induced by aspiration of the amygdala to those induced by fiber-sparing neurotoxic lesions. Four different stimuli, two with and two without a social component, were used to evaluate the expression of Defense, Aggression, Submission, and Approach responses. In unoperated controls, Defense and Approach behaviors were elicited by all four stimuli, "social" and inanimate alike, whereas Aggression and Submission responses occurred only in the presence of the two "social" stimuli. Furthermore, all Defense reactions were reduced with an attractive inanimate item, while Freezing was selectively increased with an aversive one. Relative to controls, monkeys with neurotoxic amygdala lesions showed the same array of behavioral changes as those with aspiration lesions, namely reduced fear and aggression, increased submission, and excessive manual and oral exploration. Even partial neurotoxic lesions involving less than two-thirds of the amygdala significantly altered fear and manual exploration. These findings convincingly demonstrate that the amygdala is crucial for the normal regulation of emotions in monkeys. Nevertheless, since some of the symptoms observed after neurotoxic lesions were less marked than those seen after aspiration lesions, the emotional disorders described earlier after amygdalectomy in monkeys were likely exacerbated by the attendant fiber damage

    Chandra Observations of "The Antennae" Galaxies (NGC 4038/39)

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    We report the results of a deep Chandra ACIS pointing at the merging system NGC 4038/39. We detect an extraordinarily luminous population of X-ray sources, with luminosity well above that of XRBs in M31 and the Milky Way. If these sources are unbeamed XRBs, our observations may point to them being 10-100Mo black hole counterparts. We detect an X-ray bright hot ISM, with features including bright superbubbles associated with the actively star-forming knots, regions where hot and warm (Hα\alpha) ISM intermingle, and a large-scale outflow.Comment: 7 pages, 10 figures, Accepted for publication in Ap

    Diffusion of Point Defects in Two-Dimensional Colloidal Crystals

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    We report the first study of the dynamics of point defects, mono and di-vacancies, in a confined 2-D colloidal crystal in real space and time using digital video microscopy. The defects are introduced by manipulating individual particles with optical tweezers. The diffusion rates are measured to be Dmono/a23.27±0.03D_{mono}/a^{2}\cong3.27\pm0.03Hz for mono-vacancies and Ddi/a23.71±0.03D_{di}/a^{2}\cong3.71\pm0.03Hz for di-vacancies. The elementary diffusion processes are identified and it is found that the diffusion of di-vacancies is enhanced by a \textit{dislocation dissociation-recombination} mechanism. Furthermore, the defects do not follow a simple random walk but their hopping exhibits memory effects, due to the reduced symmetry (compared to the triangular lattice) of their stable configurations, and the slow relaxation rates of the lattice modes.Comment: 6 pages (REVTEX), 5 figures (PS

    Machine Assisted Proof of ARMv7 Instruction Level Isolation Properties

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    In this paper, we formally verify security properties of the ARMv7 Instruction Set Architecture (ISA) for user mode executions. To obtain guarantees that arbitrary (and unknown) user processes are able to run isolated from privileged software and other user processes, instruction level noninterference and integrity properties are provided, along with proofs that transitions to privileged modes can only occur in a controlled manner. This work establishes a main requirement for operating system and hypervisor verification, as demonstrated for the PROSPER separation kernel. The proof is performed in the HOL4 theorem prover, taking the Cambridge model of ARM as basis. To this end, a proof tool has been developed, which assists the verification of relational state predicates semi-automatically
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