414 research outputs found

    IS COMMUNITY INVOLVEMENT BENEFICIAL FOR PUBLIC POLICY EFFICIENCY?

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    Replaced with revised version of paper 08/02.Political Economy,

    Addressing business agility challenges with enterprise systems

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    It is clear that systems agility (i.e., having a responsive IT infrastructure that can be changed quickly to meet changing business needs) has become a critical component of organizational agility. However, skeptics continue to suggest that, despite the benefits enterprise system packages provide, they are constraining choices for firms faced with agility challenges. The reason for this skepticism is that the tight integration between different parts of the business that enables many enterprise systems\u27 benefits also increases the systems\u27 complexity, and this increased complexity, say the skeptics, increases the difficulty of changing systems when business needs change. These persistent concerns motivated us to conduct a series of interviews with business and IT managers in 15 firms to identify how they addressed, in total, 57 different business agility challenges. Our analysis suggests that when the challenges involved an enterprise system, firms were able to address a high percentage of their challenges with four options that avoid the difficulties associated with changing the complex core system: capabilities already built-in to the package but not previously used, leveraging globally consistent integrated data already available, using add-on systems available on the market that easily interfaced with the existing enterprise system, and vendor provided patches that automatically updated the code. These findings have important implications for organizations with and without enterprise system architectures

    Pests and Agricultural Commodity Losses: Evaluating Alternative Approaches to Damage Function Estimation

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    Estimating the economic impact of a pest requires linking biological and economic systems via a damage function. The most common damage function approach links exogenous pest populations to cumulative commodity yield losses at harvest. This type of representation is a reduced form because is not pest population levels per se that drive damage, but the underlying factors that affect pest populations and the susceptibility of the host. We specify and estimate a structural damage function and compare the results with those of the reduced form. We do so using two alternative models, one that explains the level of crop damage from a pest, and one that explains the timing of that damage during the host’s growing season. We address our objectives within an empirical application to the olive fruit fly in California. In formulating the structural damage function, we draw from current scientific literature on olive fly and olive fruit phenology. The structural damage function takes into account the feedback between climate, host susceptibility, and pest populations. Moreover, the structural approach disaggregates damage rates across space and time, unlike the typical reduced form. The estimation results indicate that endogeneity is a salient concern in both the timing of initial crop damage, and in the levels of damage evidenced in some cultivars. The structural damage function dominates the trapping-based reduced form in terms of explanatory power in every model estimated.Crop Production/Industries,

    Implications of GATT for Eastern Europe and the Baltics

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    The story of agriculture in Eastern Europe during the last quarter century is a story of policy driven by politics, rather than by sound economics. Even in the highly distorted economics of the socialist period, agricultural policy stands out as being singularly colored by ideological imperatives, and singularly vulnerable to interest group pressures. While the revolutions of 1989-91 did mark a sharp move towards liberalization, these moves are now being slowed and even reversed, as countries of the region adopt Western style interventionism on preparation for accession to the European Union

    Simplifying and improving the extraction of nitrate from freshwater for stable isotope analyses

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    Determining the isotopic composition of nitrate (NO3_) in water can prove useful to identify NO3_ sources and to understand its dynamics in aquatic systems. Among the procedures available, the ‘ionexchange resin method’ involves extracting NO3_ from freshwater and converting it into solid silver nitrate (AgNO3), which is then analysed for 15N/14N and 18O/16O ratios. This study describes a simplified methodology where water was not pre-treated to remove dissolved organic carbon (DOC) or barium cations (added to precipitate O-bearing contaminants), which suited samples with high NO3_ ($400 mM or 25 mg L_1 NO3_) and low DOC (typically <417 mM of C or 5 mg L_1 C) levels. % N analysis revealed that a few AgNO3 samples were of low purity (compared with expected % N of 8.2), highlighting the necessity to introduce quality control/quality assurance procedures for silver nitrate prepared from field water samples. Recommendations are then made to monitor % N together with % O (expected at 28.6, i.e. 3.5 fold % N) in AgNO3 in order to better assess the type and gravity of the contamination as well as to identify potentially unreliable data

    Preliminary account of the Silurian carbon isotope record (d13Corg) from the Barrancos region, Ossa Morena Zone, Portugal

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    The Barrancos region provides one of the reference sections for the Silurian of the Ossa Morena Zone in Portugal. In this area the Silurian succession is condensed, with a maximum thickness of 50 m and the ages provided by graptolite faunas indicates that all the Silurian system is represented here. The lithologies are fairly homogenous throughout the succession consisting of black carbonaceous shales interbedded with black cherts, that were deposited in marine basins that developed at the northen margins of the Gondwana continent. This study is the first attempt to characterize the variation of 13Corg in this region, in order to assess well-documented Silurian climatic events. The studied section is located at Monte do Carreba, near Barrancos village, and consists of a 45 m thick succession of black shales and cherts with graptolite faunas that indicates a Llandovery to lower Ludlow age. The base of the section is faulted against Upper Ordovician greywackes and quartzites. In this section 13Corg shows a baseline of consistent low values ranging from -25.88 to -25.10%. This is interrupted by three positive excursions with maximum values of: -22.73% at the transition between the Llandovery (Telychian) and Wenlock (Sheinwoodian), -23.33% at the Homerian and -23.09% at the transition between the Wenlock and Ludlow (Gorstian). The excursions have positive shifts between +2.55 and +3.15% and are tentatively related to the three first global climatic events recognized for the Silurian (Ireviken, Mulde and Linde). Although this study is a preliminary account of 13Corg in this region, it could provide usefull data for the recognition and discussion of climatic global events in high latitude regions as was the OMZ located during Silurian times and for sections with high level of thermal maturation.Fundação para a Ciência e Tecnologia (FCT) (PhD grant SFRH/BD/48534/2008)

    Funneling Light Through a Subwavelength Aperture with Epsilon-Near-Zero Materials

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    Integration of the next generation of photonic structures with electronic and optical on-chip components requires the development of effective methods for confining and controlling light in subwavelength volumes. Several techniques enabling light coupling to sub-wavelength objects have recently been proposed, including grating-, and composite-based solutions. However, experi-mental realization of these couplers involves complex fabrication with \sim 10nm resolution in three dimensions. One promising alternative to complex coupling structures involves materials with vanishingly small dielectric permittivity, also known as epsilon-near-zero (ENZ) materials. In contrast to the previously referenced approaches, a single at layer of ENZ-material is expected to provide effcient coupling between free-space radiation and sub-wavelength guiding structures. Here we report the first direct observation of bulk-ENZ-enhanced transmission through a subwavelength slit, accompanied by a theoretical study of this phenomenon. Our study opens the door to multiple practical applications of ENZ materials and ENZ-based photonic systems

    Implications of Simultaneity in a Physical Damage Function

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    A modeler must often rely on highly simplified representations of complex physical systems when analyzing associated economic issues. Herein, we consider a management problem in which a bioeconomic system exhibits simultaneity in processes governing productivity and damage. In this case, it may benefit the producer to sacrifice productivity to reduce the costs associated with increased damage. We specify empirically a structural damage relationship that explains the biological process by which an invasive species damages a host and estimate the structural model and its reduced form with an exceptional dataset on infestation of olives by the olive fruit fly. We contrast the results of these models with the approach typically taken in the economic literature, which expresses damage as a function of pest density. The population-based approach introduces significantly greater bias into the individual grower\u27s choice of damage-control inputs than estimates based on the structural model

    Observations of the Askaryan Effect in Ice

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    We report on the first observations of the Askaryan effect in ice: coherent impulsive radio Cherenkov radiation from the charge asymmetry in an electromagnetic (EM) shower. Such radiation has been observed in silica sand and rock salt, but this is the first direct observation from an EM shower in ice. These measurements are important since the majority of experiments to date that rely on the effect for ultra-high energy neutrino detection are being performed using ice as the target medium. As part of the complete validation process for the Antarctic Impulsive Transient Antenna (ANITA) experiment, we performed an experiment at the Stanford Linear Accelerator Center (SLAC) in June 2006 using a 7.5 metric ton ice target, yielding results fully consistent with theoretical expectations.Comment: 4 pages, 5 figures, minor correction
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