28,149 research outputs found

    September 11: Symbolism And Responses To 9/11

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    Professors Hopkins and Hopkins review the impact of 9/11 as a symbol in American politics. Following the terrorist attacks, 9/11 became a simple reference condensing wide-ranging events and emotions. Various interpretations emerged about what caused 9/11 and enabled the attacks. The authors claim that 9/11 allowed US leaders to pursue certain policy prescriptions that otherwise would have been blocked. Among four possible prescriptions for responding to the attacks, the Bush administration chose a praetorian policy of preventive war, with Iraq as its first example. In the authors’ view, by pursuing an expansive but highly militarized response, the US has overlooked the need to alleviate the conditions that made 9/11 possible. The authors recommend that the US, as part of a multilateral effort, allocate major resources to expanding global public goods, including measures that strengthen barriers to proliferation, enhance fighting of global crime, and reduce incentives for terrorism, especially ones arising in failing states where distorted education and weak protection of human rights encourage organized terrorism

    Flocking Regimes in a Simple Lattice Model

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    We study a one-dimensional lattice flocking model incorporating all three of the flocking criteria proposed by Reynolds [Computer Graphics vol.21 4 (1987)]: alignment, centring and separation. The model generalises that introduced by O. J. O' Loan and M. R. Evans [J. Phys. A. vol. 32 L99 (1999)]. We motivate the dynamical rules by microscopic sampling considerations. The model exhibits various flocking regimes: the alternating flock, the homogeneous flock and dipole structures. We investigate these regimes numerically and within a continuum mean-field theory.Comment: 24 pages 7 figure

    Agricultural Applications of Value-at-Risk Analysis: A Perspective

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    Value-at-Risk (VaR) determines the probability of a portfolio of assets losing a certain amount in a given time period due to adverse market conditions with a particular level of confidence. Value-at-Risk has received considerable attention from financial economists and financial practitioners for its use in risk reporting, in particular the risks of derivatives. This paper provides a "state-of-the-art" review of VaR estimation techniques and empirical findings found in the finance literature. The ability of VaR estimates to represent large losses associated with tail events varies among procedure, confidence level, and data used. To date, there is no consensus to the most appropriate estimation technique. Potential applications of Value-at-Risk are suggested in the context of agricultural risk management. In the wake of the Hedge-to-Arrive crisis, the lifting of agricultural trade options by the CFTC, and the decreased government participation, VaR seems to have a place in the agricultural risk manager's toolkit.Value-at-Risk, risk management, estimation procedures

    The Forecasting Value of New Crop Futures: A Decision-Making Framework

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    The statistical forecasting efficiency of new crop corn and soybean futures is the topic of frequent academic inquiry. However, few studies address the usefulness of these forecasts to economic agents??? decision making. Each year Central Illinois producers are faced with the decision to plant either corn or soybeans on marginal acreage. Agronomic concerns aside, these decisions hinge on the expected relative return of corn versus soybeans, which is largely a function of expected new crop prices. Do new crop futures prices reliably guide producers into the correct production decision? The results suggest that over the entire period of the analysis, futures markets provide only marginal decision-making information to the producer; however, more recent signals do appear to be useful. Further analysis explores several possible factors that could explain why the signals have improved so significantly since 1985.published or submitted for publicationnot peer reviewe

    Neutrinos from the Galactic Center in the Light of its Gamma-Ray Detection at TeV Energy

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    We re-evaluate the event rate expected in km^3-scale detectors for neutrinos from the direction of the Galactic Center (GC) in light of recent spectral measurements obtained by the HESS instrument for ~TeV gamma-radiation from this direction. In the most plausible scenario the re-evaluated event rate is smaller than that previously calculated--and here re-calculated--on the basis of EGRET data. However, the GC TeV gamma-ray detections by the Whipple, CANGAROO, and HESS instruments, together with the strong indications for an overabundance of cosmic rays coming from the GC at EeV energies, strengthen the expectation for a detectable, TeV-PeV GC neutrino signal from proton-proton interactions in that region. If the TeV gamma-ray--EeV cosmic ray anisotropy connection is correct, this signal will be detectable within a year and half for km^3-scale neutrino detectors in the Northern Hemisphere at super-TeV energies and, significantly, should also be detectable in 1.6 years by the South Polar IceCube detector at energies > 10^14 eV. The GC neutrino signal should also produce a detectable signal from neutrino showering and resonant W^- production by anti-electron-neutrinos in the volume of a km^3-scale detector.Comment: 12 pages, 1 figure. Version accepted to ApJ Letters. Minor amendment

    SIC1 is ubiquitinated in vitro by a pathway that requires CDC4, CDC34, and cyclin/CDK activities

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    Traversal from G1 to S-phase in cycling cells of budding yeast is dependent on the destruction of the S-phase cyclin/CDK inhibitor SIC1. Genetic data suggest that SIC1 proteolysis is mediated by the ubiquitin pathway and requires the action of CDC34, CDC4, CDC53, SKP1, and CLN/CDC28. As a first step in defining the functions of the corresponding gene products, we have reconstituted SIC1 multiubiquitination in DEAE-fractionated yeast extract. Multiubiquitination depends on cyclin/CDC28 protein kinase and the CDC34 ubiquitin-conjugating enzyme. Ubiquitin chain formation is abrogated in cdc4ts mutant extracts and assembly restored by the addition of exogenous CDC4, suggesting a direct role for this protein in SIC1 multiubiquitination. Deletion analysis of SIC1 indicates that the N-terminal 160 residues are both necessary and sufficient to serve as substrate for CDC34-dependent ubiquitination. The complementary C-terminal segment of SIC1 binds to the S-phase cyclin CLB5, indicating a modular structure for SIC1

    Seamless metal-clad fiber-reinforced organic matrix composite structures and process for their manufacture

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    A metallic outer sleeve is provided which is capable of enveloping a hollow metallic inner member having continuous reinforcing fibers attached to the distal end thereof. The inner member is then introduced into outer sleeve until inner member is completely enveloped by outer sleeve. A liquid matrix member is then injected into space between inner member and outer sleeve. A pressurized heat transfer medium is flowed through the inside of inner member, thereby forming a fiber reinforced matrix composite material. The wall thicknesses of both inner member and outer sleeve are then reduced to the appropriate size by chemical etching, to adjust the thermal expansion coefficient of the metal-clad composite structure to the desired value. thereby forming a fiber reinforced matrix composite material. The wall thicknesses of both inner member and outer sleeve are then reduced to the appropriate size by chemical etching, to adjust the thermal expansion coefficient of the metal-clad composite structure to the desired value. The novelty of this invention resides in the development of a efficient method of producing seamless metal clad fiber reinforced organic matrix composite structures

    The Forecasting Value of New Crop Futures: A Decision-Making Framework

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    The statistical forecasting efficiency of new crop corn and soybean futures is the topic of frequent academic inquiry. However, few studies address the usefulness of these forecasts to economic agents' decision making. Each year Central Illinois producers are faced with the decision to plant either corn or soybeans on marginal acreage. Agronomic concerns aside, these decisions hinge on the expected relative return of corn versus soybeans, which is largely a function of expected new crop prices. Do new crop futures prices reliably guide producers into the correct production decision? The results suggest that over the entire period of the analysis, futures markets provide only marginal decision- making information to the producer; however, more recent signals do appear to be useful. Further analysis explores several possible factors that could explain why the signals have improved so significantly since 1985.forecasting efficiency, futures prices, decision making

    TIME-VARYING MULTIPRODUCT HEDGE RATIO ESTIMATION IN THE SOYBEAN COMPLEX: A SIMPLIFIED APPROACH

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    In developing optimal hedge ratios for the soybean processing margin, many authors have illustrated the importance of considering the interactions between the cash and futures prices for soybeans, soybean oil, and soybean meal. Conditional as well as time-varying hedge ratios have been examined, but in the case of multiproduct time-varying hedge ratios, the difficulty in estimation has been found to often outweigh any improvement in hedging effectiveness. This research examines the hedging effectiveness of the Risk Metrics procedure for estimating a time-varying covariance matrix for developing optimal hedge ratios for the soybean processing margin. The Risk Metrics method allows for a time-varying covariance matrix while being considerably easier to implement than multivariate GARCH (MGARCH) procedures. The Risk Metrics procedure has been advocated for use in developing Value-at-Risk estimates. While it provided considerable out-of-sample improvement in hedging effectiveness relative to a constant correlation MGARCH procedure, the Risk Metrics method provided only minimal improvement over a naive (1-to-1) hedging strategy. However, this research does illustrate the potential for the Risk Metrics methodology as a viable alternative to MGARCH procedures in a multiproduct hedging context.Marketing,
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