2,036 research outputs found

    Intermediaries in agro-food networks in Turkey: How middlemen respond to transforming food market structures

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    Traditional wholesale intermediaries in the fresh fruit and vegetable segment tend to get expendable in markets with an increasing demand for traceability and for the fulfilment of quality and hygiene standards. The demand for these specifications is usually induced by transnational retail corporations that enter new market environments. This is also the case for Turkey, where since 2010 trade with fresh fruit and vegetable products can be conducted outside wholesale markets. Dualistic structures in accordance with socio-economic realities have emerged and the reactions of intermediaries towards these transformations vary between strategies of resilience and reworking. Therefore completely new purchasing channels emerge, whereby at the same time long-established trading patterns remain important to supply all groups of the society. This article is based on interviews conducted in Turkey

    A high resolution Mirnov array for the Mega Ampere Spherical Tokamak

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    Over the past two decades, the increase in neutral-beam heating and alpha particle production in magnetically confined fusion plasmas has led to an increase in energetic particle driven mode activity, much of which has an electromagnetic signature which can be detected by the use of external Mirnov coils. Typically, the frequency and spatial wave number band of such oscillations increase with increasing injection energy, offering new challenges for diagnostic design. In particular, as the frequency approaches the megahertz range, care must be taken to model the stray capacitance of the coil, which limits the resonant frequency of the probe; model transmission line effects in the system, which if unchecked can produce system resonances; and minimize coil conductive shielding, so as to minimize skin currents which limit the frequency response of the coil. As well as optimizing the frequency response, the coils should also be positioned to confidently identify oscillations over a wide wave number band. This work, which draws on new techniques in stray capacitance modeling and coil positioning, is a case study of the outboard Mirnov array for high-frequency acquisition in the Mega Ampere Spherical Tokamak, and is intended as a roadmap for the design of high frequency, weak field strength magnetic diagnostics.This work was partly funded by the Australian National University, the United Kingdom Engineering and Physical Sciences Research Council, and by the European Communities under the contract of Association between EURATOM and CCFE

    Modeling of thin-walled frames mechatronic systems with fillet welds and their influence on the natural frequency

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    Práce popisuje metody redukce počtu stupňů volnosti a její aplikace na mechatronický systém. Další část se zabývá problematikou koutových svarů a jejich modelování v programu Ansys Workbench. Jednotlivé možnosti geometrie svarů jsou podrobeny modální, statické a harmonické analýze. Cílem práce je porovnání výsledků analýz pro různé metody geometrie koutového svaru. Dále práce srovnává výsledky modální analýzy v programech Ansys Workbench a Adams. A v poslední řadě se práce zabývá též možnostmi exportu z programu Ansys Workbench do programu Adams, Matlab a Excel.This bachelor thesis is focused on methods of reduction degrees of freedom and their application in mechatronical system. Next part is focused on fillet welds and their modelling in Ansys Workbench software. Individual possibilities of geometry of welds are analysed by modal, static and harmonic analysis. Aim of this thesis is comparison of results of analysis for different methods of geometry of welds. Then it compare results of modal analysis in Ansys Workbench and Adams software. Finally the work deals with possibilities of exporting from Ansys Workbench to Adams, Matlab and Excel software.

    Application of optimization methods for parameters estimation of simulation models

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    Tato práce se zabývá problematikou hledání odhadu parametrů. V rámci práce byl vytvořen nový program, který umožňuje provádět hledání odhadu parametrů, podobně jak nástroj Parametr estimation, který je součástí rozšiřujícího balíčku Matlabu. Nově vytvořený program vhodnou vizualizací a novými funkcemi umožňuje pro některé případy nalezení lepšího odhadu parametrů než program od Mathworks.This thesis deals with parameters estimation search problematics. Newly-made software is proposed within a frame of this work and it replaces and supplements the Parameter Estimation tool, which is a part of Matlab toolbox. New software proposes suitable visualisation and new functions, which may lead to better solutions than build-in tools in Matlab.

    Inclusive Jet Cross Sections in pˉp\bar{p}p Collisions at s\sqrt{s}= 630 and 1800 GeV

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    We have made a precise measurement of the inclusive jet cross section at s\sqrt{s}=1800 GeV. The result is based on an integrated luminosity of 92 pb^{-1} collected at the Fermilab Tevatron pˉp\bar{p}p Collider with the D\O detector. The measurement is reported as a function of jet transverse energy (60 GeV <= E_{T} < 550 GeV), and in the pseudorapidity intervals |\eta| <= 0.5 and 0.1 <= |\eta| <= 0.7. A preliminary measurement of the pseudorapidity dependence of inclusive jet production (|\eta| <= 1.5) is also discussed. The results are in good agreement with predictions from next-to-leading order (NLO) quantum chromodynamics (QCD). D\O has also determined the ratio of jet cross sections at s\sqrt{s}=630 GeV and s\sqrt{s}=1800 GeV (|\eta| <= 0.5). This preliminary measurement differs from NLO QCD predictions.Comment: Submitted to the International Europhysics Conference on High Energy Physics, EPS-HEP99, 15-21 July, 1999, Tampere, Finlan

    Survival of animal and human associated <i>Listeria monocytogenes</i> in drinking water and biofilms

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    Land slugs are occasionally observed as contaminants in groundwater wells and drinking water treatment plants including storage tanks. Slugs may feed on carrion and feces, and they are potential vectors of pathogens such as Listeria monocytogenes. We isolated L monocytogenes from the pest slug Arion vulgaris and examined the persistence and survival of human- and slug-derived L. monocytogenes in groundwater-based drinking water and biofilms. L monocytogenes survival was evaluated using cultivation and cultivation-independent techniques. L monocytogenes remained culturable for 35-47 days in drinking water with first-order decay rates between 0.314 and 0.457 hr1 (T99 &gt;10 days). Attachment of L monocytogenes to filter sand delayed washout from drinking water filters and increased persistence 2-3-fold. Indigenous biofilms stimulated initial surface attachment 10-100-fold butL. monocytogenes declined more rapidly in drinking water biofilms compared with virgin filters not colonized by microorganisms. Grazing by protozoa likely attenuated L monocytogenes survival in some drinking water biofilms. A comparable survival pattern was observed for L monocytogenes and the fecal indicator bacterium E. coli. The study suggests that live L monocytogenes can persist for weeks as sessile organisms in groundwater-based drinking water supplies and may subsequently be released to the drinking water.</p

    Viral promoters can initiate expression of toxin genes introduced into Escherichia coli

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    BACKGROUND: The expression of recombinant proteins in eukaryotic cells requires the fusion of the coding region to a promoter functional in the eukaryotic cell line. Viral promoters are very often used for this purpose. The preceding cloning procedures are usually performed in Escherichia coli and it is therefore of interest if the foreign promoter results in an expression of the gene in bacteria. In the case molecules toxic for humans are to be expressed, this knowledge is indispensable for the specification of safety measures. RESULTS: We selected five frequently used viral promoters and quantified their activity in E. coli with a reporter system. Only the promoter from the thymidine kinase gene from HSV1 showed no activity, while the polyhedrin promoter from baculovirus, the early immediate CMV promoter, the early SV40 promoter and the 5' LTR promoter from HIV-1 directed gene expression in E. coli. The determination of transcription start sites in the immediate early CMV promoter and the polyhedrin promoter confirmed the existence of bacterial -10 and -35 consensus sequences. The importance of this heterologous gene expression for safety considerations was further supported by analysing fusions between the aforementioned promoters and a promoter-less cytotoxin gene. CONCLUSION: According to our results a high percentage of viral promoters have the ability of initiating gene expression in E. coli. The degree of such heterologous gene expression can be sufficient for the expression of toxin genes and must therefore be considered when defining safety measures for the handling of corresponding genetically modified organisms

    Heavy Quark Correlations in Photon-Hadron Collisions

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    We describe a next-to-leading-order calculation of the fully exclusive parton cross section for the photoproduction of heavy quarks. We use our result to compute quantities of interest for current fixed-target experiments. We discuss heavy-quark total cross sections, distributions and correlations.Comment: 34 pages (LaTex) + 15 figures (topdrawer, included at the end) CERN-TH 6921/93, GEF-TH-15/199

    Top Quark Production Cross Section

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    The production rate for top quarks at the Fermilab Tevatron is presented using the exact order αs3\alpha_s^3 corrected cross section and the resummation of the leading soft gluon corrections in all orders of perturbation theory.Comment: preprint FERMILAB-Pub-93/270-T, ITP-SB-93-55, THU-93/23, Latex 9 pages, 8 postscript figures, uuencoded and appended at end of fil
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