357 research outputs found

    Rhizobium inoculant formulation and placement in lentil and chickpea in the semiarid Canadian prairies

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    Non-Peer ReviewedLentil and chickpea are the major pulse crops grown in western Canada, but little is known about the responses of these annual legumes to rhizobium inoculant formulation, placement, and their interaction to fertilizers under semiarid environments. A field study was conducted from 1999 to 2002 on a medium-textured soil at Swift Current and on a heavy clay soil at Stewart Valley, both in Saskatchewan. The objectives were to (i) determine the effects of rhizobium inoculation and fertilization on nodule formation, N2-fixation, and their impacts on growth, yield, and seed quality in chickpea and lentil, and (ii) develop recommendations for optimizing rhizobium inoculation, P-solublizing inoculation, and fertilizer N and P application for direct-seeding of chickpea and lentil with 1-, 2-, and 3-tank delivery systems. The results of the six site-years showed that use of rhizobium inoculation increased seed yield by 35% for desi, 7% for kabuli, and 23% for lentil. Inoculation reduced desi plant population by 10%, but not in kabuli or lentil. Granular inoculant increased yield by 7% in chickpea and 8% in lentil, compared to peat-based powder inoculant. Placement of granular inoculant (seed-row vs side-banding) had the same effect in all three pulses. Starter-N and starter-P at a rate of 15 kg ha-1 each had a marginal effect on plant growth and seed yield, but a higher rate of P (34 kg P2O5 ha-1) increased kabuli seed size. Chickpea and lentil did not show any response to Penicillium bilaii (fungus contained in the products JumpStart® and TagTeam®) under the semiarid growing conditions

    Investment under ambiguity with the best and worst in mind

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    Recent literature on optimal investment has stressed the difference between the impact of risk and the impact of ambiguity - also called Knightian uncertainty - on investors' decisions. In this paper, we show that a decision maker's attitude towards ambiguity is similarly crucial for investment decisions. We capture the investor's individual ambiguity attitude by applying alpha-MEU preferences to a standard investment problem. We show that the presence of ambiguity often leads to an increase in the subjective project value, and entrepreneurs are more eager to invest. Thereby, our investment model helps to explain differences in investment behavior in situations which are objectively identical

    Factor copula models for item response data

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    Factor or conditional independence models based on copulas are proposed for multivariate discrete data such as item responses. The factor copula models have interpretations of latent maxima/minima (in comparison with latent means) and can lead to more probability in the joint upper or lower tail compared with factor models based on the discretized multivariate normal distribution (or multidimensional normal ogive model). Details on maximum likelihood estimation of parameters for the factor copula model are given, as well as analysis of the behavior of the log-likelihood. Our general methodology is illustrated with several item response data sets, and it is shown that there is a substantial improvement on existing models both conceptually and in fit to data

    First Incursion of Salmonella enterica Serotype Typhimurium DT160 into New Zealand

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    An outbreak of human Salmonella enterica serotype Typhimurium DT160 infection in New Zealand was investigated from May to August 2001. Handling of dead wild birds, contact with persons with diarrheal illness, and consumption of fast food were associated with infection. Contaminated roof-collected rainwater was also detected

    Symmetry Nonrestoration in a Gross-Neveu Model with Random Chemical Potential

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    We study the symmetry behavior of the Gross-Neveu model in three and two dimensions with random chemical potential. This is equivalent to a four-fermion model with charge conjugation symmetry as well as Z_2 chiral symmetry. At high temperature the Z_2 chiral symmetry is always restored. In three dimensions the initially broken charge conjugation symmetry is not restored at high temperature, irrespective of the value of the disorder strength. In two dimensions and at zero temperature the charge conjugation symmetry undergoes a quantum phase transition from a symmetric state (for weak disorder) to a broken state (for strong disorder) as the disorder strength is varied. For any given value of disorder strength, the high-temperature behavior of the charge conjugation symmetry is the same as its zero-temperature behavior. Therefore, in two dimensions and for strong disorder strength the charge conjugation symmetry is not restored at high temperature.Comment: 16 pages, 3 figure

    An aggravated trajectory of depression and anxiety co-morbid with hepatitis C: : A 21 to 62 month follow-up study in 61 South Australian outpatients

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    BACKGROUND: This study aimed to explore the course of depression and anxiety in chronic hepatitis C patients. METHODS:   Data were combined from two studies: (1) Hospital Anxiety and Depression Scale (HADS) scores in 395 consecutive Australian outpatients from 2006 to 2010 formed the baseline measurement; and (2) Depression Anxiety Stress Scales (DASS) scores in a survey of a sub-sample of these patients in 2011 formed the follow-up measurement. After converting DASS to HADS scores, changes in symptom scores and rates of case-ness (≥8), and predictors of follow-up symptoms were assessed. RESULTS:   Follow-up data were available for 61 patients (70.5% male) whose age ranged from 24.5 to 74.6 years (M=45.6). The time to follow-up ranged from 20.7 to 61.9 months (M=43.8). Baseline rates of depression (32.8%) and anxiety (44.3%) increased to 62.3% and 67.2%, respectively. These findings were confirmed, independent of the conversion, by comparing baseline HADS and follow-up DASS scores with British community norms. Baseline anxiety and younger age predicted depression, while baseline anxiety, high school non-completion, and single relationship status predicted anxiety. CONCLUSION:  This study demonstrated a worsening trajectory of depression and anxiety. Further controlled and prospective research in a larger sample is required to confirm these findings

    On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

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    A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)
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