6,553 research outputs found

    Wheat Forward Contract Pricing: Evidence on Forecast Power and Risk Premia

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    While the risk premium hypothesis in futures markets has been the subject of a long and continuous controversy, the risk premium hypothesis in forward markets is also of interest among economists. The hypothesis is supported by some theoretical arguments and empirical evidence yet remains an open question. We in this study apply a two-equation regression model similar to those used in (Fama and French (1987} and de Roon et al. (1998) to analyze the risk premiums in forward markets, particularly, using the pre-harvest wheat forward markets in Illinois (1982-2004) and Kansas (1990-2004) as an example. The two-equation regression model consists of a forecasting equation, which uses a forward basis during a pre-harvest period to forecast the spot basis at the following harvest period, and a risk premium equation, which uses the forward basis to predict the risk premium to be realized at the harvest. The empirical results show that, first, the average realized risk premiums for Illinois fluctuate around a level during the entirety of a pre-harvest period, while the risk premiums for Kansas show a slight downward trend as time approaches the harvest. The average realized risk premiums are generally positive and bigger for Illinois than for Kansas, but all mean risk premiums are within one units of their corresponding standard deviations. Second, the pre-harvest forward bases have reliable forecasting power for the spot harvest bases and contain information regarding the risk premiums, which strongly recommend estimating risk premiums conditional on forward bases.Marketing,

    The Marketing Performance of Illinois and Kansas Wheat Farmers

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    The purpose of this paper is to analyze the marketing performance of wheat farmers in Illinois and Kansas over 1982–2004. The results show that farmer benchmark prices for wheat in Illinois and Kansas fall in the middle third of the price range about half to three-quarters of the time. Consistent with previous studies, this refutes the contention that Illinois and Kansas wheat farmers routinely market the bulk of their wheat crop in the bottom portion of the price range. Tests of the average difference between farmer and market benchmark prices are sensitive to the market benchmark considered. The marketing performance of wheat farmers in Illinois and Kansas is about equal to the market if a 24- or 20-month market benchmark is used, slightly above the market if a 12-month price benchmark is used, and significantly less than the market if the harvest benchmark is used. The sensitivity of marketing performance to the market benchmark considered is explained by the seasonal pattern of prices. While Illinois producers performed slightly better than their counterparts in Kansas, notable differences in performance across these two geographic areas is not observed.benchmarks, Illinois, Kansas, marketing, performance, price, wheat, Agribusiness, Crop Production/Industries, Marketing, Production Economics, Productivity Analysis, Q11, Q13,

    The optical transmission spectrum of the hot Jupiter HAT-P-32b: clouds explain the absence of broad spectral features?

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    We report Gemini-North GMOS observations of the inflated hot Jupiter HAT-P-32b during two primary transits. We simultaneously observed two comparison stars and used differential spectro-photometry to produce multi-wavelength light curves. 'White' light curves and 29 'spectral' light curves were extracted for each transit and analysed to refine the system parameters and produce transmission spectra from 520-930nm in ~14nm bins. The light curves contain time-varying white noise as well as time-correlated noise, and we used a Gaussian process model to fit this complex noise model. Common mode corrections derived from the white light curve fits were applied to the spectral light curves which significantly improved our precision, reaching typical uncertainties in the transit depth of ~2x10^-4, corresponding to about half a pressure scale height. The low resolution transmission spectra are consistent with a featureless model, and we can confidently rule out broad features larger than about one scale height. The absence of Na/K wings or prominent TiO/VO features is most easily explained by grey absorption from clouds in the upper atmosphere, masking the spectral features. However, we cannot confidently rule out clear atmosphere models with low abundances (~10^-3 solar) of TiO, VO or even metal hydrides masking the Na and K wings. A smaller scale height or ionisation could also contribute to muted spectral features, but alone are unable to to account for the absence of features reported here.Comment: 17 pages, 11 figures, 2 tables, accepted for publication in MNRA

    A Gemini ground-based transmission spectrum of WASP-29b: a featureless spectrum from 515 to 720nm

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    We report Gemini-South GMOS observations of the exoplanet system WASP-29 during primary transit as a test case for differential spectrophotometry. We use the multi-object spectrograph to observe the target star and a comparison star simultaneously to produce multiple light curves at varying wavelengths. The 'white' light curve and fifteen 'spectral' light curves are analysed to refine the system parameters and produce a transmission spectrum from 515 to 720nm. All light curves exhibit time-correlated noise, which we model using a variety of techniques. These include a simple noise rescaling, a Gaussian process model, and a wavelet based method. These methods all produce consistent results, although with different uncertainties. The precision of the transmission spectrum is improved by subtracting a common signal from all the spectral light curves, reaching a typical precision of ~1x10^-4 in transit depth. The transmission spectrum is free of spectral features, and given the non-detection of a pressure broadened Na feature, we can rule out the presence of a Na rich atmosphere free of clouds or hazes, although we cannot rule out a narrow Na core. This indicates that Na is not present in the atmosphere, and/or that clouds/hazes play a significant role in the atmosphere and mask the broad wings of the Na feature, although the former is a more likely explanation given WASP-29b's equilibrium temperature of ~970 K, at which Na can form various compounds. We also briefly discuss the use of Gaussian process and wavelet methods to account for time correlated noise in transit light curves.Comment: 15 pages, 9 figures, 3 tables. Published in MNRAS. Figure 2 corrected in version

    A/r/cography: art, research and communication

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    This article aims at establishing the foundations for a/r/cography as an “art and communication”-based research methodology, inspired by a/r/tography yet more encompassing, and particularly suitable for the digital art world. As part of the larger family of practice-based research methodologies, a/r/tography presents various ways through which it can be explored, but since it is aimed at the arts and education, its scope is forcibly hampered by the fact that not all researchers and art practitioners are necessarily teachers. However, since most of its underlying principles can be extended for non-teachers, thus arose the idea to propose a methodology that would retain ontological, epistemological and methodological assumptions, but would expand beyond the limitations imposed by the role of the teacher. This extension is called a/r/cography and is structured upon the interchangeable roles of artist, researcher and communicator, as being intrinsic to the underlying living inquiry processes. Furthermore, this proposal is supported by the author’s own experience from a/r/cographic processes in the creation, exhibition and communication of digital artworks.info:eu-repo/semantics/publishedVersio

    Investigation of Reactivity of Launch Vehicle Materials with Liquid Oxygen

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    Impact sensitivity and ignition mechanism of organic compounds in liquid oxygen correlated with chemical and physical propertie
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