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| Koyama, Kohei; Yamamoto, Ken; Ushio, Masayuki. |
| Lognormal distributions and self-similarity are characteristics associated with a wide range of biological systems. The sequential breakage model has established a link between lognormal distributions and self-similarity and has been used to explain species abundance distributions. To date, however, there has been no similar evidence in studies of multicellular organismal forms. We tested the hypotheses that the distribution of the lengths of terminal stems of Japanese elm trees (Ulmus davidiana), the end products of a self-similar branching process, approaches a lognormal distribution. We measured the length of the stem segments of three elm branches and obtained the following results: (i) each occurrence of branching caused variations or errors in the... |
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Palavras-chave: Allometry; Fractal; Phenotypic plasticity; Shoot size; Stochastic process; WBE theory. |
| Ano: 2017 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4577 |
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| Hennessy, David A.. |
| The use of plausible stochastic price processes in price risk analysis has allowed advances not seen in crop yield risk analysis. This study develops a stochastic process for yield modeling and risk management. The Pólya urn process is an internally consistent dynamic representation of yield expectations over a growing season that accommodates agronomic events such as growing degree days. The limiting distribution is the commonly used beta distribution. Binomial tree analysis of the process allows us to explore hedging decisions and crop valuation. The method is empirically flexible to accommodate alternative assumptions on the growing environment, such as intra-season input decisions. |
| Tipo: Journal Article |
Palavras-chave: Crop abandonment; Crop insurance; Derivative analysis; Growing degree days; Pólya’s urn; Stochastic process; Crop Production/Industries. |
| Ano: 2011 |
URL: http://purl.umn.edu/105548 |
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