10,284 research outputs found

    Impact of noise on domain growth in electroconvection

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    The growth and ordering of striped domains has recently received renewed attention due in part to experimental studies in diblock copolymers and electroconvection. One surprising result has been the relative slow dynamics associated with the growth of striped domains. One potential source of the slow dynamics is the pinning of defects in the periodic potential of the stripes. Of interest is whether or not external noise will have a significant impact on the domain ordering, perhaps by reducing the pinning and increasing the rate of ordering. In contrast, we present experiments using electroconvection in which we show that a particular type of external noise decreases the rate of domain ordering

    Generalized Stacking Fault Energy Surfaces and Dislocation Properties of Silicon: A First-Principles Theoretical Study

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    The generalized stacking fault (GSF) energy surfaces have received considerable attention due to their close relation to the mechanical properties of solids. We present a detailed study of the GSF energy surfaces of silicon within the framework of density functional theory. We have calculated the GSF energy surfaces for the shuffle and glide set of the (111) plane, and that of the (100) plane of silicon, paying particular attention to the effects of the relaxation of atomic coordinates. Based on the calculated GSF energy surfaces and the Peierls-Nabarro model, we obtain estimates for the dislocation profiles, core energies, Peierls energies, and the corresponding stresses for various planar dislocations of silicon.Comment: 9 figures (not included; send requests to [email protected]

    Industry Clusters and Food Value Chains: Can the Literature on Local Collective Failure be used as a Guide for Assessing and Overcoming Value Chain Failure?

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    In this paper the literature on industry clusters as a response to local collective failure is reviewed as a way of enhancing knowledge about how failure of food value chains to perform efficiently can be analysed and overcome. The conclusion is that there is much in the local collective failure literature that assists in an understanding of, and is consistent with, the concepts of value chain failure, value chain externalities and value chain goods. Four potential areas for enhancing the analysis of value chains by accessing this literature are noted: defining the boundary between chain failure and local collective failure; improving joint action among parties interested in overcoming chain failure; augmenting the processes of knowledge creation and application in value chains; and improving the governance of value chains. The key point is that the ability of local collective or value chain partners to produce chain goods and internalise positive chain externalities depends directly on the nature and intent of the joint action by the partners: will they cooperate or not, and, if they do cooperate, how and to what extent will they do so? These issues of coordination of economic activity and the nature of the relationships between partners go to the heart of governance within both local communities and value chains

    Linear Chains of Styrene and Methyl-Styrene Molecules and their Heterojunctions on Silicon: Theory and Experiment

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    We report on the synthesis, STM imaging and theoretical studies of the structure, electronic structure and transport properties of linear chains of styrene and methyl-styrene molecules and their heterojunctions on hydrogen-terminated dimerized silicon (001) surfaces. The theory presented here accounts for the essential features of the experimental STM data including the nature of the corrugation observed along the molecular chains and the pronounced changes in the contrast between the styrene and methyl-styrene parts of the molecular chains that are observed as the applied bias is varied. The observed evolution with applied bias of the STM profiles near the ends of the molecular chains is also explained. Calculations are also presented of electron transport along styrene linear chains adsorbed on the silicon surface at energies in the vicinity of the molecular HOMO and LUMO levels. For short styrene chains this lateral transport is found to be due primarily to direct electron transmission from molecule to molecule rather than through the silicon substrate, especially in the molecular LUMO band. Differences between the calculated position-dependences of the STM current around a junction of styrene and methyl-styrene molecular chains under positive and negative tip bias are related to the nature of lateral electron transmission along the molecular chains and to the formation in the LUMO band of an electronic state localized around the heterojunction.Comment: 17 pages plus 11 figures. To appear in Physical Review

    The New World challenge : Performance trends in wine production in major wine-exporting countries in the 2000s and their implications for the Australian wine industry

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    © 2014 UniCeSV, University of Florence. Anderson, K., Nelgen, S., 2011. Global Wine Markets, 1961 to 2009: A Statistical Compendium. University of Adelaide Press, Adelaide publication of an index of revealed comparative advantage suggests that the Australian wine industry had come under increased competition from other "New World" producers in the first decade of this century. We examine this influence by comparing the transformation of wine grapes into wine volume and value in the 11 largest wine-exporting countries during the years, 2000-2009. Our focus is on the challenge issued by other New World producers from the Southern Hemisphere to Australian producers, and the continuing challenge to Old World global supremacy by New World producers and its response. Four performance measures are used this study. Two key trends are evident. First, all countries migrated to higher price points, albeit with differing degrees of success: slightly declining productivity in transforming wine grapes into wine output was over whelmed by price/quality effects, leading to substantial gains in transforming wine grapes in to wine value. Second, New World producers plus Portugal and Spain were much more successful in achieving gains in their export value proposition than they were in extracting value in their domestic markets. Results show that Australian wine producers had lost some of their competitive advantage during the 2000s as their pre- existing strategy dominated by the export of high-volume wines by large companies at low to medium price points, and their reliance on a reputation for reliable good quality for the price point was beginning to fail in the face of competition from both New World and Old World producers. Acknowledgement of this outcome has led to a good deal of introspection, and recognition of the need to promote the wine regions of Australia, based on higher-quality wines,and to select and promote quality indicators

    The Consumers' Choice of Purchasing Location and the Preferences for Beef in Yogyakarta

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    This study aims to analyze the consumer preferences about choosing a place to buy beef and beef attribute product influence in buying decision of consumers in Yogyakarta. There were 300 beef consumers selected near traditional markets, butcher or meat shops, supermarkets, restaurants and food stalls for the survey using the questionnaire. The data were analyzed descriptively and used the chi-square test to evaluate the relationship between demographic characteristics and the consumers' choice of place when buying beef in Yogyakarta. The study reveals that most respondents buy beef at butcher or meat shops, followed by traditional markets and supermarkets. Consumers consider price, top quality of beef, the freshness of the product, shopping convenience and friends with sellers as the top five reasons when they choose a place to buy beef. Further, there is no correlation between demographic aspects with consumer preferences in choosing a place to buy beef. Finally, the beef attributes consumers consider when buying beef are the halal slaughtering method, bright red colour, quality assured and beef cuts

    Embryo abortion as mechanism of "hormone" thinning of fruit

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    Digitized 2007 AES.Includes bibliographical references (pages 67-79)

    Spectroscopy on two coupled flux qubits

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    We have performed spectroscopy measurements on two coupled flux qubits. The qubits are coupled inductively, which results in a σ1zσ2z\sigma_1^z\sigma_2^z interaction. By applying microwave radiation, we observe resonances due to transitions from the ground state to the first two excited states. From the position of these resonances as a function of the magnetic field applied we observe the coupling of the qubits. The coupling strength agrees well with calculations of the mutual inductance

    Spectroscopy of a Cooper-Pair box in the Autler-Townes configuration

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    A theoretical spectroscopic analysis of a microwave driven superconducting charge qubit (Cooper-pair box coupled) to an RLC oscillator model is performed. By treating the oscillator as a probe through the backreaction effect of the qubit on the oscillator circuit, we extract frequency splitting features analogous to the Autler-Townes effect from quantum optics, thereby extending the analogies between superconducting and quantum optical phenomenology. These features are found in a frequency band that avoids the need for high frequency measurement systems and therefore may be of use in qubit characterization and coupling schemes. In addition we find this frequency band can be adjusted to suit an experimental frequency regime by changing the oscillator frequency.Comment: 13 pages, 7 figures. v2: Revised version after referee comments. Accepted for publication by Physical Review
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