110 research outputs found

    Member Commitment and the Market and Financial Performance of the Saskatchewan Wheat Pool

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    Since 2001 several of the largest agricultural co-operatives in Western Canada and the United States have battled impending bankruptcy or ceased operations. In February 2001 Dairyworld Foods was bought out by Montreal dairy processor and cheese producer Saputo Inc. (Saputo; Toronto Stock Exchange). In November 2001, Agricore, formed through a 1998 merger of Alberta Wheat Pool Ltd. and Manitoba Pool Elevators, merged with United Grain Growers to form Agricore United (Agricore United). In the United States, AgWay and Farmland Industries filed for Chapter 11 bankruptcy protection in 2002 (Reuters, 2000), while the Saskatchewan Wheat Pool (hereinafter referred to as SWP or the Pool) underwent a massive debt restructuring in 2003 after four years of consecutive multi-million dollar net losses (SWP Annual Report, 2003). This decline in the market and financial performance of agricultural co-operatives has been associated with a decline in the commitment of the members to their co-operatives (Fulton, 1999; Fulton and Giannakas, 2001; Richards, Klein and Walburger, 1998; Burt and Wirth, 1990). The purpose of this article is to examine the market and financial performance of one of a number of co-operatives that have faced recent financial and market hardships, and to link this performance to member commitment. Specifically, the article examines whether the Pool’s declining market and financial performance is consistent with the predictions that emerge from a model that examines the impact of falling member commitment in a co-operative.Marketing,

    Infusing the UN Sustainable Development Goals into a global learning initiative

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    The Global Citizens Project (GCP) is a university-wide global learning initiative at the University of South Florida, aimed at enhancing undergraduate students’ global competencies through curricular and co-curricular experiences. The GCP uses the United Nations Sustainable Development Goals (SDGs) as a framework for these experiences. Understanding the SDGs allows students to expand their ideas on issues that exist in the world and how we might respond to the challenges. The purpose of this article is to provide a case study showing how the GCP has introduced students from all disciplines and undergraduate degree programmes to the SDGs through interdisciplinary workshops, with the aim of helping them to better understand the SDGs and connect global issues to their academic goals, professional objectives and everyday experiences. To determine whether the aims of the workshops were met, qualitative content analysis is employed to analyse the constructed responses of students who attended them. The results of the study suggest that the SDGs provide a relevant and sufficiently robust framework for guiding undergraduate students in their thinking about global issues as well as their relationship with these issues

    Poisson structures on affine spaces and flag varieties. I. Matrix affine Poisson space

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    The standard Poisson structure on the rectangular matrix variety Mm,n(C) is investigated, via the orbits of symplectic leaves under the action of the maximal torus T ⊂ GLm+n(C). These orbits, finite in number, are shown to be smooth irreducible locally closed subvarieties of Mm,n(C), isomorphic to intersections of dual Schubert cells in the full flag variety of GLm+n(C). Three different presentations of the T-orbits of symplectic leaves in Mm,n(C) are obtained – (a) as pullbacks of Bruhat cells in GLm+n(C) under a particular map; (b) in terms of rank conditions on rectangular submatrices; and (c) as matrix products of sets similar to double Bruhat cells in GLm(C) and GLn(C). In presentation (a), the orbits of leaves are parametrized by a subset of the Weyl group Sm+n, such that inclusions of Zariski closures correspond to the Bruhat order. Presentation (b) allows explicit calculations of orbits. From presentation (c) it follows that, up to Zariski closure, each orbit of leaves is a matrix product of one orbit with a fixed column-echelon form and one with a fixed rowechelon form. Finally, decompositions of generalized double Bruhat cells in Mm,n(C) (with respect to pairs of partial permutation matrices) into unions of T-orbits of symplectic leaves are obtained

    Scaling Of The Coulomb Energy Due To Quantum Fluctuations In The Charge Of A Quantum Dot

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    The charging energy of a quantum dot is measured through the effect of its potential on the conductance of a second dot. This technique allows a measurement of the scaling of the dot's charging energy with the conductance of the tunnel barriers leading to the dot. We find that the charging energy scales quadratically with the reflection probability of the barriers. In a second experiment we study the transition from a single to a double-dot which exhibits a scaling behavior linear in the reflection probability. The observed power-laws agree with a recent theory.Comment: 5 pages, uuencoded and compressed postscript file, with figure

    Charge Transport in Voltage-Biased Superconducting Single-Electron Transistors

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    Charge is transported through superconducting SSS single-electron transistors at finite bias voltages by a combination of coherent Cooper-pair tunneling and quasiparticle tunneling. At low transport voltages the effect of an ``odd'' quasiparticle in the island leads to a 2e2e-periodic dependence of the current on the gate charge. We evaluate the IVI-V characteristic in the framework of a model which accounts for these effects as well as for the influence of the electromagnetic environment. The good agreement between our model calculation and experimental results demonstrates the importance of coherent Cooper-pair tunneling and parity effects.Comment: RevTeX, 12 pages, 4 figure

    Torus-invariant prime ideals in quantum matrices, totally nonnegative cells and symplectic leaves

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    The algebra of quantum matrices of a given size supports a rational torus action by automorphisms. It follows from work of Letzter and the first named author that to understand the prime and primitive spectra of this algebra, the first step is to understand the prime ideals that are invariant under the torus action. In this paper, we prove that a family of quantum minors is the set of all quantum minors that belong to a given torus-invariant prime ideal of a quantum matrix algebra if and only if the corresponding family of minors defines a non-empty totally nonnegative cell in the space of totally nonnegative real matrices of the appropriate size. As a corollary, we obtain explicit generating sets of quantum minors for the torus-invariant prime ideals of quantum matrices in the case where the quantisation parameter qq is transcendental over Q\mathbb{Q}.Comment: 16 page

    Risk assessment for epidemic spread of the quarantined potato pathogen Synchytrium endobioticum in the Republic of Georgia

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    Synchytrium endobioticum (causal agent of potato wart) is a devastating soilborne pathogen. Eradication is difficult and infestation can result in 100% yield loss, making this a strictly quarantined pathogen worldwide. Emerging epidemics pose a high risk to production in Georgia where potato is an essential staple, grown primarily by smallholder farmers, and yields are among the world’s lowest. S. endobioticum was first reported in Georgia in 2014 in a localized outbreak in Adjara. Because pathogen dissemination is primarily via human transport of infested tubers, understanding the local potato seed system is critical. This study was the first to systematically characterize the actors involved in seed and ware potato production and trade in Georgia. To collect this information, an expert elicitation was conducted in 2017 across a broad range of participants from the Georgian potato production sector. We present a model of the current potato seed exchange network for the most important agroecological regions. We integrated network analysis in a risk assessment for S. endobioticum spread in Georgia under 1) no intervention, 2) quarantine, 3) introduction of host plant resistance, and 4) combined quarantine and resistance deployment. Preliminary analyses suggest that under no intervention, risk of spread is high, while rapid and consistent quarantine can be effective. Methods presented here provide a general framework for future seed system risk assessments

    XANES evidence for sulphur speciation in Mn-, Ni- and W-bearing silicate melts

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    Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 73 (2009): 6847-6867, doi:10.1016/j.gca.2009.08.013.S K edge XANES and Mn, W and Ni XANES and EXAFS spectra of silicate glasses synthesised at 1400° C and 1 bar with compositions in the CaO-MgO-Al2O3-SiO2-S plus MnO, NiO, or WO3 systems were used to investigate sulphur speciation in silicate glasses. S K-edge spectra comprised a composite peak with an edge between 2470 and 2471.4 eV, which was attributed to S2-, and a peak of variable height with an edge at 2480.2 to 2480.8 eV, which is consistent with the presence of S6+. The latter peak was attributed to sample oxidation during sample storage. W-rich samples produced an additional lower energy peak at 2469.8 eV that is tentatively attributed to the existence of S 3p orbitals hybridised with the W 5d states. Deconvolution of the composite peak reveals that the composite peak for Mn-bearing samples fits well to a model that combines three Lorentzians at 2473.1, 2474.9 and 2476.2 eV with an arctan edge step. The composite peak for W-bearing samples fits well to the same combination plus an additional Lorentzian at 2469.8 eV. The ratio of the proportions of the signal accounted for by peaks at 2473.1eV and 2476.2eV correlates with Mn:Ca molar ratios, but not with W:Ca ratios. Spectra from Ni-bearing samples were qualitatively similar but S levels were too low to allow robust quantification of peak components. Some part of the signal accounted for by the 2473.1 eV peak was therefore taken to record the formation of Mn-S melt species, while the 2469.8 peak is interpreted to record the formation of W-S melt species. The 2474.9 eV and 2476.2 eV peaks were taken to be dominated by Ca-S and Mg-S interactions. However, a 1:1 relationship between peak components and specific energy transitions is not proposed. This interpretation is consistent with known features of the lower parts of the conduction band in monosulphide minerals and indicates a similarity between sulphur species in the melts and the monosulphides. S XANES spectra cannot be reproduced by a combination of the spectra of the component element monosulphides. Mn-, W- and Ni- XANES and EXAFS for synthetic glasses without sulphide exsolution did not show any sensitivity to the presence of sulphur, which is unsurprising as S:O ratios were sufficiently low that metals would be mostly co-ordinated by O. Mn EXAFS spectra were consistent with divalent Mn in 5 co-ordinated Mn-O melt species. W spectra were consistent with tetrahedrally co-ordinated hexavalent W, most likely in scheelite-like melt species, and Ni spectra were consistent with [4] co-ordinated divalent Ni. These results indicate lower coordinations for bothWand Ni than those inferred by some previous workers. Cation coordination may reflect the proportion of non-bridging oxygens, which is lower in the Ca-rich and Al-poor samples investigated here than for previous studies.This work was performed with 814 support from the Australian Synchrotron Research Program (ASRP), which is funded by the 815 Commonwealth of Australia under the Major National Research Facilities Program

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

    The TESS-Keck Survey. II. An Ultra-Short-Period Rocky Planet And Its Siblings Transiting The Galactic Thick-Disk Star TOI-561

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    We report the discovery of TOI-561, a multiplanet system in the galactic thick disk that contains a rocky, ultra-short-period planet. This bright (V = 10.2) star hosts three small transiting planets identified in photometry from the NASA TESS mission: TOI-561 b (TOI-561.02, P = 0.44 days, Rp = 1.45 ± 0.11 R⊕), c (TOI-561.01, P = 10.8 days, Rp = 2.90 ± 0.13 R⊕), and d (TOI-561.03, P = 16.3 days, Rp = 2.32 ± 0.16 R⊕). The star is chemically ([Fe/H] = −0.41 ± 0.05, [α/Fe] = +0.23 ± 0.05) and kinematically consistent with the galactic thick-disk population, making TOI-561 one of the oldest (10 ± 3 Gyr) and most metal-poor planetary systems discovered yet. We dynamically confirm planets b and c with radial velocities from the W. M. Keck Observatory High Resolution Echelle Spectrometer. Planet b has a mass and density of 3.2 ± 0.8 M⊕ and 5.51.6+2.0{5.5}_{-1.6}^{+2.0}g cm−3, consistent with a rocky composition. Its lower-than-average density is consistent with an iron-poor composition, although an Earth-like iron-to-silicates ratio is not ruled out. Planet c is 7.0 ± 2.3 M⊕ and 1.6 ± 0.6 g cm−3, consistent with an interior rocky core overlaid with a low-mass volatile envelope. Several attributes of the photometry for planet d (which we did not detect dynamically) complicate the analysis, but we vet the planet with high-contrast imaging, ground-based photometric follow-up, and radial velocities. TOI-561 b is the first rocky world around a galactic thick-disk star confirmed with radial velocities and one of the best rocky planets for thermal emission studies
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