1,848 research outputs found
ASSESSING THE FINANCIAL RISKS OF DIVERSIFIED COFFEE PRODUCTION SYSTEMS: AN ALTERNATIVE NONNORMAL CDF ESTIMATION APPROACH
No full textRecently developed techniques are adapted and combined for the modeling and simulation of crop yields and prices that can be mutually correlated, exhibit heteroskedasticity or autocorrelation, and follow nonnormal probability density functions. The techniques are applied to the modeling and simulation of probability distribution functions for the returns of three tropical agroforestry systems for coffee production. The importance of using distribution functions that can more closely reflect the statistical behavior of yields and prices for risk analysis is discussed and illustrated.Risk and Uncertainty,
The Effect of Consumption Based Taxes on Agriculture in the United States
No full textRecently several proposals have arisen to replace the current income tax system in the United States with a consumption based or Fair Tax. This study investigates the effect of such a consumption based tax on agricultural investment decisions using stochastic optimal control to model the investment decision at the farm level. The results indicate that a consumption tax rate of 25.9 percent would be equivalent to the income tax rate paid by very large producers in the United States.Public Economics,
Flammability features of native and non-native woody species from the southernmost ecosystems: a review
No full textOTO y AFR están financiados por ANID/Basal FB210015 (CENAMAD) y agradecen el apoyo recibido de ANID SCIA-Anillo ACT210052. AFR reconoce subvenciones DIUFRO PP23-0016 y Capital Semilla PCS 2021/017 CENAMAD. RAG gracias a ANID/Basal FB210006. Dos revisores hicieron una serie de comentarios y sugerencias que mejoraron enormemente el manuscrito
In immigration reform, undocumented immigrants value work visas and family visits more than access to healthcare and social security.
No full textWith a wide-range of competing immigration reform bills being debated in a gridlocked U.S. congress, the question remains: can a compromise bill ever emerge and what is the optimal form it should take? Surprisingly, there is little evidence on the immigration reform attributes most valued by the group who will be most affected: illegal immigrants themselves. Grace Melo, Gregory Colson, and Octavio Ramirez examine the tradeoff and dollar value Hispanic immigrants place on different attributes of competing U.S. Senate and House immigration reform bills. They find that illegal immigrants place a substantial value on long-term work visas, a path to citizenship, and the ability for family members to be eligible for visitation rights. Notably, a green card is valued approximately the same as a ten year work visa. Access to government safety nets including medical care and social security are valued to a lesser extent
PARAMETRIC MODELING AND SIMULATION OF JOINT PRICE-PRODUCTION DISTRIBUTIONS UNDER NON-NORMALITY, AUTOCORRELATION AND HETEROSCEDASTICITY: A TOOL FOR ASSESSING RISK IN AGRICULTURE
No full textThis study presents a way to parametrically model and simulate multivariate distributions under potential non-normality, autocorrelation and heteroscedasticity and illustrates its application to agricultural risk analysis. Specifically, the joint probability distribution (pdf) for West Texas irrigated cotton, corn, sorghum, and wheat production and prices is estimated and applied to evaluate the changes in the risk and returns of agricultural production in the region resulting from observed and predicted price and production trends. The estimated pdf allows for time trends on the mean and the variance and varying degrees of autocorrelation and non-normality (kurtosis and right- or left-skewness) in each of the price and production variables. It also allows for any possible price-price, production-production, or price-production correlation.agricultural risk analysis, autocorrelation, heteroscedasticity, multivariate non-normal simulation, West Texas agriculture, Research Methods/ Statistical Methods, Risk and Uncertainty,
La hija de Rappaccini de Octavio Paz: análisis e interpretación de una farsa trágica
No full text"Este trabajo tiene como objetivo analizar el texto dramático La hija de Rappaccini, única obra de teatro de Octavio Paz. “La hija de Rappaccini de Octavio Paz: análisis e interpretación de una farsa trágica”, consta de cuatro capítulos. El primero, “Tópicos y perspectivas de acercamiento a La hija de Rappaccini de Octavio Paz", se encarga de abordar, en primera instancia, la problemática que representa la escasez de estudios críticos del texto y, de los existentes, los acercamientos son mínimos y escuetos, en cuanto a un análisis dramático propiamente dicho. En este sentido, el capítulo analiza los artículos encontrados y los tópicos que giran en torno al drama paciano: Rappaccini’s daughter-La hija de Rappaccini de Hawthorne y paz respectivamente. La idea es, precisamente, poner sobre la mesa que, las rutas para abordar el texto se han conducido en ideas que se convierten en tópicos o lugares comunes, como la comparación mencionada y la recurrencia forzosa a las ideas y obras del autor; amén de la importancia de ello, este trabajo considera pertinente y justo realizar un análisis donde la óptica del texto gire los reflectores hacia el análisis dramático, propio del género literario al que pertenece.
RISK AND RETURNS OF DIVERSIFIED CROPPING SYSTEMS UNDER NONNORMAL, CROSS-, AND AUTOCORRELATED COMMODITY PRICE STRUCTURES
No full textThis study analyzes the risks of diversified tropical cropping systems that combine cocoa, plantain, and tree-crop components in different proportions versus traditional monocultures. A technique for modeling the expected values, variances, and covariances of correlated time-series variables that are autocorrelated and nonnormal (right or left skewed and kurtotic) is applied to simulate commodity prices. The importance of using simulated cumulative density functions (cdf's) which reflect the most important characteristics of the stochastic behavior of prices for analyzing risk and returns of diversified agricultural systems is demonstrated. The analysis priovides evidence in favor of diversified cocoa-plantain-Cordia agroforestry system technologies versus the traditional monocultures.Demand and Price Analysis,
AUTOREGRESSIVE CONDITIONAL HETEROSKEDASTICY UNDER ERROR-TERM NON-NORMALITY
No full textThis paper explores the impact of error-term non-normality on the performance of the normal-error Generalized Autoregressive Conditional Heteroskedastic (GARCH) model under small and moderate sample sizes. A non-normal-, asymmetric-error GARCH model is proposed, and its finite-sample performance is evaluated in comparison to the normal-error GARCH under various underlying error-term distributions. The results suggest that one must be skeptical of using the normal-error GARCH when there is evidence of conditional error-term non-normality. The conditional distribution of the error-term in a previous mainstream application of the normal GARCH is found to be non-normal and asymmetric. The same application is used to illustrate the advantages of the proposed non-normal-error GARCH model.Error- term non-normality, skewness, autoregressive conditional heteroskedasticity, Research Methods/ Statistical Methods,
An Empirically-Grounded Comparison of the Johnson System versus the Beta as Crop Yield Distribution Models
No full textPrevious research established that the expanded Johnson system can accommodate any theoretically possible mean-variance-skewness-kurtosis combination. Therefore, it has been hypothesized that this system can provide for a reasonably accurate modeling approximation of any probability distribution that might be encountered in practice. In order to test that hypothesis, this manuscript develops a more flexible expanded form of the Beta distribution which, in its original form, has been widely used to model and simulate crop yields for risk analysis. Empirically grounded evaluations suggest that the Johnson system can model a variety of typical yield data-generating processes that are based on the Beta distribution much more precisely than the Beta can model representative crop yield data simulated from the Johnson system. The accuracy with which the Johnson system approximates the Beta supports the previously stated hypothesis.Crop Production/Industries,
Technology\u27s Unexpected Consequences
No full textGetting people excited about science is the passion of Ainissa Ramirez, author and science “evangelist,” who spreads her “gospel” through books, TED Talks, online videos and the podcast “Science Underground.” She was named one of the world’s 100 Top Young Innovators by Technology Review for her contributions to transforming technology and has been the recipient of the American Institute of Physics’ Andrew Gemant Award.
Ramirez spent eight years teaching mechanical engineering & materials science as an associate professor at Yale University and also has been a visiting professor at MIT. She is the author or coauthor of three books, including 2013’s “Newton’s Football: The Science Behind America’s Game,” an entertaining and enlightening look at the big ideas underlying the science of football.
She has served as a science advisor to the American Film Institute, WGBH/NOVA and the American Association for the Advancement of Science, among others.
Her appearance is supported by the Spoerl Lectureship in Science in Society
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