742 research outputs found

    External equity financing of agrifood firms

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    Title from PDF of title page (University of Missouri--Columbia, viewed on May 30, 2012).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Peter G. KleinVita.Ph.D. University of Missouri-Columbia, 2011"December 2011"This dissertation investigates the determinants that influence a firm's decision to use external private equity in agriculture. Scholars have recognized the benefits of external equity finance for agricultural firms (i.e., capital derived from a source other than retained earnings and existing owners) and the use of external equity in agriculture has increased since 1990. This is important because this source of capital allows farms to exploit business opportunity, particularly for companies that pose risks that discourage debt capital, and because private equity has fostered entrepreneurial activity. However, the literature addressing this phenomenon is limited. The asset specificity approach (Williamson 1988) offers insightful contributions to understand the choice of financial mechanisms. This approach brings additional insights and complements agency -- the dominant perspective in finance. The analysis focuses on the differential redeployability of the assets involved in the production of different agricultural product. I construct an international dataset of agricultural companies that receive external private equity finance to test hypotheses about the determinants of using external equity finance. Results show that the attributes of the assets involved in agriculture are important factors to explain financing choices in agriculture. This research contributes to the understanding of the role of asset specificity to explain financing decisions and to the identification of what types of asset specificity play an important role in agriculture.Includes bibliographical reference

    Determinantes dos arranjos contratuais1: O caso da transação produtor-processador de carne bovina no Uruguai

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    What are the determinants of the commercial channel choice in the beef producers-processors transactions? The question refers to the coordination and production control problem associated to changes in consumer’s awareness of specific attributes in food products. Two contractual arrangements coexist in this transaction: direct-contracting and broker-induced transactions Transaction Cost Economic offers helpful insights to understand the reason for the development and adaptations of different contractual arrangement moved by transaction cost economizing perspective. The empirical analysis is focused in the Uruguayan beef agro-industrial system. Analysis integrates (i) institutional and organizational changes in the beef industry; (ii) based on the analysis of the transaction dimensions (frequency, asset specificity and uncertainty) we address hypothesis of the determinants of the contractual arrangement in the beef producers-processors transaction; and (iii) we run a statistical test of the hypotheses based on a logit model. We used a panel data with producers-processors transaction from Uruguayan Agricultural Bureau (77,000 transactions). We confirm the hypotheses of the determinants of the contractual arrangement choice. The probability of a transaction being aligned with the direct contractual arrangement increase in transaction with higher asset specificity (i.e., young steer), lower distance between the producer and the processor, and with higher frequency of transaction.Vertical Coordination, Beef System, Contractual arrangement, Transaction Cost Economics, Agribusiness, D23, L14, Q13,

    Disorder effects in the quantum Heisenberg model: An Extended Dynamical mean-field theory analysis

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    We investigate a quantum Heisenberg model with both antiferromagnetic and disordered nearest-neighbor couplings. We use an extended dynamical mean-field approach, which reduces the lattice problem to a self-consistent local impurity problem that we solve by using a quantum Monte Carlo algorithm. We consider both two- and three-dimensional antiferromagnetic spin fluctuations and systematically analyze the effect of disorder. We find that in three dimensions for any small amount of disorder a spin-glass phase is realized. In two dimensions, while clean systems display the properties of a highly correlated spin-liquid (where the local spin susceptibility has a non-integer power-low frequency and/or temperature dependence), in the present case this behavior is more elusive unless disorder is very small. This is because the spin-glass transition temperature leaves only an intermediate temperature regime where the system can display the spin-liquid behavior, which turns out to be more apparent in the static than in the dynamical susceptibility.Comment: 15 pages, 7 figure

    Intrinsic susceptibility and bond defects in the novel 2D frustrated antiferromagnet Ba2_{2}Sn2_{2}ZnCr7p_{7p}Ga107p_{10-7p}O22_{22}

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    We present microscopic and macroscopic magnetic properties of the highly frustrated antiferromagnet Ba2_{2}Sn2_{2}ZnCr7p_{7p}Ga107p_{10-7p}O22_{22}, respectively probed with NMR and SQUID experiments. The TT-variation of the intrinsic susceptibility of the Cr3+^{3+} frustrated kagom\'{e} bilayer, χkag\chi_{kag}, displays a maximum around 45 K. The dilution of the magnetic lattice has been studied in detail for 0.29p0.970.29 \leq p \leq0.97. Novel dilution independent defects, likely related with magnetic bond disorder, are evidenced and discussed. We compare our results to SrCr9p_{9p}Ga129p_{12-9p}O19_{19}. Both bond defects and spin vacancies do not affect the average susceptibility of the kagom\'{e} bilayers.Comment: Published in Phys. Rev. Lett. 92, 217202 (2004). Only minor changes as compared to previous version. 4 pages, 4 figure

    Spin dynamics of heterometallic Cr7M wheels (M = Mn, Zn, Ni) probed by inelastic neutron scattering

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    Inelastic neutron scattering has been applied to the study of the spin dynamics of Cr-based antiferromagnetic octanuclear rings where a finite total spin of the ground state is obtained by substituting one Cr(III) ion (s = 3/2) with Zn (s = 0), Mn (s = 5/2) or Ni (s = 1) di-cations. Energy and intensity measurements for several intra-multiplet and inter-multiplet magnetic excitations allow us to determine the spin wavefunctions of the investigated clusters. Effects due to the mixing of different spin multiplets have been considered. Such effects proved to be important to correctly reproduce the energy and intensity of magnetic excitations in the neutron spectra. On the contrary to what is observed for the parent homonuclear Cr8 ring, the symmetry of the first excited spin states is such that anticrossing conditions with the ground state can be realized in the presence of an external magnetic field. Heterometallic Cr7M wheels are therefore good candidates for macroscopic observations of quantum effects.Comment: 9 pages, 11 figures, submitted to Phys. Rev. B, corrected typos and added references, one sentence change

    Evidence for two disparate spin dynamic regimes within Fe-substituted La0.7 Pb0.3 (Mn1-x Fex) O3 (0≤x≤0.2) colossal magnetoresistive manganites: Neutron spin-echo measurements

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    10 págs.; 7 figs.; 1 tab. ; PACS number s : 75.25. z, 75.30.Ds, 75.40.Gb, 75.47.GkThe spin dynamics of substituted colossal magnetoresistive (CMR) manganites of general formula La0.7 Pb0.3 (Mn1-x Fex) O3, 0≤x≤0.2 is investigated by means of neutron spin-echo measurements. Substitution of Mn by Fe leads to a strong decrease of the temperature of macroscopic magnetic long-range ordering with a concomitant enhancement of the CMR effect. For x=0.2, a long-range-ordered state is not achieved as a result of the increase in antiferromagnetic interactions brought forward by Fe+3 -Mn couplings. The results display two relaxations having well separated decay constants. A fast process with a relaxation time of about 10 ps within the paramagnetic phase is found for all compositions. It shows a remarkably strong dependence with temperature and sample composition as the apparent activation energy for spin diffusion as well as the preexponential term exemplify. The physical origin of such a fast relaxation is assigned to heavily damped or overdamped spin waves (spin diffusion) on the basis of some signatures of excitations having finite frequencies found for the parent compound La0.7 Pb0.3 Mn O3 at temperatures just below Tc, together with preliminary data on the effect of Fe doping on the stiffness constant. A slower relaxation is present for all compositions. Its temperature dependence follows the behavior of the macroscopic magnetization, and its intensity grows within the ordered ferromagnetic state. Its physical origin is ascribed to collective reorientation of nanoscale ferromagnetic domains on the basis of the wave-vector dependence of its relaxation rate and amplitude. © 2007 The American Physical Society.J.G. and J.M.B. thank the Spanish Ministerio de Educacion y Ciencia for financial support under research Grant No. MAT2005-0686-C04-03. F.J.B. and P.R. acknowledge financial support from the European Commission through NMI3 to carry out preliminary measurements at the FZJ facilities.Peer Reviewe

    Development of Industrial Catalysts for Sustainable Chlorine Production

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    The heterogeneously catalyzed gas-phase oxidation of HCl to Cl2 offers an energy-efficient and eco- friendly route to recover chlorine from HCl-containing byproduct streams in the chemical industry. This process has attracted renewed interest in the last decade due to an increased chlorine demand and the growing excess of byproduct HCl from chlorination processes. Since its introduction (by Deacon in 1868) and till recent times, the industrialization of this reaction has been hindered by the lack of sufficiently active and durable materials. Recently, RuO2-based catalysts with outstanding activity and stability have been designed and they are being implemented for large-scale Cl2 recycling. Herein, we review the main limiting features of traditional Cu-based catalysts and survey the key steps in the development of the new generation of industrial RuO2-based materials. As the expansion of this technology would benefit from cheaper, but comparably robust, alternatives to RuO2-based catalysts, a nov el CeO2-based catalyst which offers promising perspectives for application in this field has been introduced

    Ga-NMR local susceptibility of the kagome-based magnet SrCr_9pGa_(12-9p)O_19. A high temperature study

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    We report a high-TT Ga-NMR study in the kagome-based antiferromagnetic compound SrCr9p_{9p}Ga129p_{12-9p}O19_{19} (.81p.96.81\leq p\leq .96), and present a refined mean-field analysis of the high T local NMR susceptibility of Cr frustrated moments. We find that the intralayer kagome coupling is J=86(6)J=86(6) K, and the interlayer coupling through non-kagome Cr moments is J=69(7)J^{\prime }=69(7) K. The J/J=0.80(1)J^{\prime}/J=0.80(1) ratio confirms the common belief that the frustrated entity is a pyrochlore slab.Comment: 8 pages, 4 figures Conference paper: Highly Frustrated Magnetism 2000, Waterloo (Canada) Submitted to Canadian Journal of Physic

    White matter integrity as a predictor of response to treatment in first episode psychosis

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    The integrity of brain white matter connections is central to a patient's ability to respond to pharmacological interventions. This study tested this hypothesis using a specific measure of white matter integrity, and examining its relationship to treatment response using a prospective design in patients within their first episode of psychosis. Diffusion tensor imaging data were acquired in 63 patients with first episode psychosis and 52 healthy control subjects (baseline). Response was assessed after 12 weeks and patients were classified as responders or non-responders according to treatment outcome. At this second time-point, they also underwent a second diffusion tensor imaging scan. Tract-based spatial statistics were used to assess fractional anisotropy as a marker of white matter integrity. At baseline, non-responders showed lower fractional anisotropy than both responders and healthy control subjects (P < 0.05; family-wise error-corrected), mainly in the uncinate, cingulum and corpus callosum, whereas responders were indistinguishable from healthy control subjects. After 12 weeks, there was an increase in fractional anisotropy in both responders and non-responders, positively correlated with antipsychotic exposure. This represents one of the largest, controlled investigations of white matter integrity and response to antipsychotic treatment early in psychosis. These data, together with earlier findings on cortical grey matter, suggest that grey and white matter integrity at the start of treatment is an important moderator of response to antipsychotics. These findings can inform patient stratification to anticipate care needs, and raise the possibility that antipsychotics may restore white matter integrity as part of the therapeutic response
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