159 research outputs found

    Media Analysis on Volatile Markets’ Dynamics and Adaptive Behavior for the Agri-Food System

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    The volatility of agricultural markets has increased remarkably in recent years. In spite of this, the way in which supply chain actors perceive market volatility has only rarely been analyzed. This paper seeks to close this research gap by presenting empirical findings about how the volatility of agricultural markets is perceived, how increasing market volatilities are being explained, and what adaptations to the volatile external environments are being suggested. Based on a large-scale media analysis, we have identified perceptions, which vary greatly over time, especially with regard to the perception of the threats and opportunities volatility creates for farms and firms and the most frequently identified reasons for volatile pricesagriculture, media analysis, public discourse, shared assumptions, volatility, Agribusiness, Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Production Economics, Research Methods/ Statistical Methods, Risk and Uncertainty,

    alpha_s and the tau hadronic width

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    Different choices exist for the renormalisation group resummation in the determination of αs\alpha_s from hadronic τ\tau decays: namely fixed-order (FOPT) and contour-improved perturbation theory (CIPT). The two approaches lead to systematic differences in the resulting αs\alpha_s. On the basis of a model for higher-order terms in the perturbative series, which incorporates well-known structure from renormalons, it is found that while CIPT is unable to account for the fully resummed series, FOPT smoothly approaches the Borel sum. Employing the model to determine αs\alpha_s yields αs(Mτ)=0.316±0.006\alpha_s(M_\tau)=0.316 \pm 0.006, which after evolution leads to αs(MZ)=0.1180±0.0008\alpha_s(M_Z) = 0.1180 \pm 0.0008.Comment: 6 pages, 2 figures. Talk given at the 10th International Workshop on Tau Lepton Physics, Novosibirsk, Russia, Sep. 22-25, 200

    Extraction of m_s and |V_us| from Hadronic Tau Decays

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    We review recent work to determine the strange quark mass m_s as well as the proposal to determine |V_{us}| using hadronic tau decay data. The recent update of the strange spectral function by OPAL and their moments of the invariant mass distribution are employed. Our results are |V_us|=0.2208 +- 0.0034 and m_s (2 GeV)=81 +- 22 MeV. Our result is already competitive to the standard extraction of |V_us| from K_e3 decays and to the new proposals to determine it. The error on V_us is dominated by experiment and will be eventually much improved by the B-factories hadronic tau data. Ultimately, a simultaneous fit of both m_s and |V_us| to a set of moments of the hadronic tau decays invariant mass distribution will provide one of the most accurate determinations of these Standard Model parameters.Comment: Invited talk given by J.P. at TAU04, 14-17 September 2004, Nara (Japan

    V_us and m_s from hadronic tau decays

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    Recent experimental results on hadronic tau decays into strange particles by the OPAL collaboration are employed to determine V_us and m_s from moments of the invariant mass distribution. Our results are V_us = 0.2208+-0.0034 and m_s(2 GeV) = 81+-22 MeV. The error on V_us is dominated by experiment, and should be improvable in the future. Nevertheless, already now our result is competitive to the standard extraction of V_us from K_e3 decays, and it is compatible with unitarity.Comment: 4 pages, 1 figur

    Recent progress in hadronic tau decays

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    The determination of alpha_s from hadronic tau decays is impeded by the fact that two choices for the renormalisation group resummation, namely fixed-order (FOPT) and contour-improved perturbation theory (CIPT), yield systematically differing results. On the basis of a model for higher-order terms in the perturbative series, which incorporates well-known structure from renormalons, it is found that FOPT smoothly approaches the Borel sum for the tau hadronic width, while CIPT is unable to account for the resummed series. An example for the behaviour of QCD spectral function moments, displaying a similar behaviour, is presented as well.Comment: 6 pages, 3 figures. Talk presented at 11th International Workshop on Tau Lepton Physics, Manchester, UK, 13-17 September 201

    Automated Reading Passage Generation with OpenAI's Large Language Model

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    The widespread usage of computer-based assessments and individualized learning platforms has resulted in an increased demand for the rapid production of high-quality items. Automated item generation (AIG), the process of using item models to generate new items with the help of computer technology, was proposed to reduce reliance on human subject experts at each step of the process. AIG has been used in test development for some time. Still, the use of machine learning algorithms has introduced the potential to improve the efficiency and effectiveness of the process greatly. The approach presented in this paper utilizes OpenAI's latest transformer-based language model, GPT-3, to generate reading passages. Existing reading passages were used in carefully engineered prompts to ensure the AI-generated text has similar content and structure to a fourth-grade reading passage. For each prompt, we generated multiple passages, the final passage was selected according to the Lexile score agreement with the original passage. In the final round, the selected passage went through a simple revision by a human editor to ensure the text was free of any grammatical and factual errors. All AI-generated passages, along with original passages were evaluated by human judges according to their coherence, appropriateness to fourth graders, and readability

    Contour-improved versus fixed-order perturbation theory in hadronic tau decays

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    The hadronic decay rate of the tau lepton serves as one of the most precise determinations of the QCD coupling alpha_s. The dominant theoretical source of uncertainty at present resides in the seeming disparity of two approaches to improving the perturbative expansion with the help of the renormalisation group, namely fixed-order and contour-improved perturbation theory. In this work it is demonstrated that in fact both approaches yield compatible results. However, the fixed-order series is found to oscillate around the contour-improved result with an oscillation frequency of approximately six perturbative orders, approaching it until about the 30th order, after which the expansion reveals its asymptotic nature. Additionally, the renormalisation scale and scheme dependencies of the perturbative series for the tau hadronic width are investigated in detail.Comment: 20 pages, 5 eps-figures; discussion on scale and scheme dependence added as compared to published journal version JHEP 09 (2005) 05

    Food Chain Actors’ Perceptions of and Adaptations to Volatile Markets: Results of a Media Analysis

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    The volatility of agricultural markets has increased remarkably in recent years. In spite of this, the way in which supply chain actors perceive market volatility has only rarely been analyzed. This paper seeks to close this research gap by presenting empirical findings about how the volatility of agricultural markets is perceived, how increasing market volatilities are being explained, and what adaptations to the volatile external environments are being suggested. Based on a large scale media analysis, we have identified perceptions, which vary greatly over time, especially with regard to the perception of the threats and opportunities volatility creates for farms and firms and the most frequently identified reasons for volatile prices
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