430 research outputs found

    The Effects of a Self-Directed Behavior Change on Self-Concept

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    The effects on self-concept as a result of behavior changes made during a self-directed self-modification project were studied on 16 students at Utah State University over a period of nine weeks. Pre and post measures of self-concept administered were the Tennessee Self Concept Scale and the Well-Being Scale from the California Psychological Inventory. The research design employed was the pretest-.posttest control group design. A separate analysis of covariance was run for the Total P raw score of the Tennessee Self Concept Scale and raw scores on the Well-Being Scale. The F was substantially short of the value of F needed for significance. The hypothesis that a behavior change would result in a self concept change was not supported. It was hypothesized that a behavior change was not the only variable that controlled self-concept. It was suggested that a more homogeneous group of subjects be used in further research, one where all the subjects were changing the same behavior, and then control for education and age

    In Search of the "Bank Lending Channel": Causality Analysis for the Transmission Mechanism of U.S. Monetary Policy

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    The bank lending channel states that changes in monetary policy cause changes in bank loans thus causing changes in real income. This implies the Federal Reserve can influence real income by controlling the level of intermediated loans. We apply a new method to test for an operative bank lending channel in the transmission mechanism of monetary policy. Combining an error correction model with directed acyclic graphs, we explore the existence of a bank lending channel and the effectiveness of U.S. monetary policy since 1960. This paper shows when an operative bank lending channel existed, explains its impact, and evaluates other channels of monetary policy.Financial Economics,

    THE LAW OF ONE PRICE: DEVELOPED AND DEVELOPING COUNTRY MARKET INTEGRATION

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    The Law of One Price (LOP) is important to models of international trade and exchange rate determination. This study investigates a variant of the LOP applied to developed and developing countries. The competing hypothesis are (1) that one price prevails in both developed and developing countries and (2) that one price prevails in developed countries and another single price in developing countries. Using data from an internationally competitive commodity (soybean meal), we found evidence favors the first hypothesis, although two large developing countries under study are active participants in regional trade integration, which may bias them against the first hypothesis.law of one price, developing countries, error-correction model, directed graphs, Demand and Price Analysis,

    Enterprise-level risk assessment of geographically diversified commercial farms: a copula approach

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    As agriculture becomes more industrialized, the role of risk measures such as value-at-risk (VaR) will become more utilized. In this case it was applied to geographical diversification and also modifying the traditional VaR estimation by incorporating a copula dependence parameter into the VaR estimation. In addition, an alternative risk measure was also calculated, CVaR. The CVaR, unlike VaR, is a coherent risk measure. Thus it does not suffer from many of the shortcomings of the VaR. The land portfolio consisted of Dryland wheat production acres in Texas, Colorado, and Montana. Three series of net returns were calculated for each region. Based on the VaR and the CVaR, the portfolio was optimized based on minimizing the expected loss based on historical net revenues. The results showed that diversification could be reduced by producing in all three areas.Copula, CVaR, Risk-Management, Geographical Diversification, Agribusiness, Farm Management, Risk and Uncertainty,

    Multi-Period Asset Allocation: An Application of Discrete Stochastic Programming

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    The issue of modeling farm financial decisions in a dynamic framework is addressed in this paper. Discrete stochastic programming is used to model the farm portfolio over the planning period. One of the main issues of discrete stochastic programming is representing the uncertainty of the data. The development of financial scenario generation routines provides a method to model the stochastic nature of the model. In this paper, two approaches are presented for generating scenarios for a farm portfolio problem. The approaches are based on copulas and optimization. The copula method provides an alternative to the multivariate normal assumption. The optimization method generates a number of discrete outcomes which satisfy specified statistical properties by solving a non-linear optimization model. The application of these different scenario generation methods is then applied to the topic of geographical diversification. The scenarios model the stochastic nature of crop returns and land prices in three separate geographic regions. The results indicate that the optimal diversification strategy is sensitive to both scenario generation method and initial acreage assumptions. The optimal diversification results are presented using both scenario generation methods.Agribusiness, Agricultural Finance, Farm Management,

    X-ray dark-field and phase retrieval without optics, via the Fokker-Planck equation

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    Emerging methods of x-ray imaging that capture phase and dark-field effects are equipping medicine with complementary sensitivity to conventional radiography. These methods are being applied over a wide range of scales, from virtual histology to clinical chest imaging, and typically require the introduction of optics such as gratings. Here, we consider extracting x-ray phase and dark-field signals from bright-field images collected using nothing more than a coherent x-ray source and detector. Our approach is based on the Fokker--Planck equation for paraxial imaging, which is the diffusive generalization of the transport-of-intensity equation. Specifically, we utilize the Fokker--Planck equation in the context of propagation-based phase-contrast imaging, where we show that two intensity images are sufficient for successful retrieval of the projected thickness and dark-field signals associated with the sample. We show the results of our algorithm using both a simulated dataset and an experimental dataset. These demonstrate that the x-ray dark-field signal can be extracted from propagation-based images, and that x-ray phase can be retrieved with better spatial resolution when dark-field effects are taken into account. We anticipate the proposed algorithm will be of benefit in biomedical imaging, industrial settings, and other non-invasive imaging applications.Comment: 16 pages, 8 figure

    Effect of Wood Particle Size on Fungal Growth in a Model Biomechanical Pulping Process

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    The pretreatment of aspen wood chips with white-rot fungus has been evaluated as a way of making biomechanical pulp. Our study addressed (1) whether wood particle size (chip size) affects the growth pattern of the attacking organism, and (2) whether the difference in particle size between chips and coarse pulp is related to the availability of wood polymers to the fungus. We qualitatively evaluated the growth of Phanerochaete chrysosporium BKM-F-1767 on aspen wood using standard industrial 6- and 19-mm chips and coarse refiner mechanical pulp. Scanning electron microscopy revealed a slight increase in the number of hyphae in the 19-mm chips compared to that in the 6-mm chips, but no major morphological differences in cellulose or lignin loss. Dense aerial hyphal growth occurred around the chips, but not around the coarse pulp. The fungus appeared to attack the coarse pulp from both outside and within the fiber wall. Hyphae within both the middle lamella and the cell lumina attacked the cell walls. The fungus eroded the chip cell walls and their constituents primarily from the wood cell lumen outward. After only 3 weeks of fungal treatment, both chips and coarse pulp showed marked localized cell-wall thinning and fragmentation as well as generalized swelling and relaxing of the normally rigid cell-wall structure. We conclude that particle size has only a minor effect on fungal growth on wood under conditions such as those likely to be used in a commercial biopulping process

    \u3cem\u3eEscherichia coli\u3c/em\u3e EDL933 Requires Gluconeogenic Nutrients To Successfully Colonize the Intestines of Streptomycin-Treated Mice Precolonized with \u3cem\u3eE. coli\u3c/em\u3e Nissle 1917

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    Escherichia coli MG1655, a K-12 strain, uses glycolytic nutrients exclusively to colonize the intestines of streptomycin-treated mice when it is the only E. coli strain present or when it is confronted with E. coli EDL933, an O157:H7 strain. In contrast, E. coli EDL933 uses glycolytic nutrients exclusively when it is the only E. coli strain in the intestine but switches in part to gluconeogenic nutrients when it colonizes mice precolonized with E. coli MG1655 (R. L. Miranda et al., Infect Immun 72:1666–1676, 2004, http://dx.doi.org/10.1128/IAI.72.3.1666-1676.2004). Recently, J. W. Njoroge et al. (mBio 3:e00280-12, 2012, http://dx.doi.org/10.1128/mBio.00280-12) reported that E. coli 86-24, an O157:H7 strain, activates the expression of virulence genes under gluconeogenic conditions, suggesting that colonization of the intestine with a probiotic E. coli strain that outcompetes O157:H7 strains for gluconeogenic nutrients could render them nonpathogenic. Here we report that E. coli Nissle 1917, a probiotic strain, uses both glycolytic and gluconeogenic nutrients to colonize the mouse intestine between 1 and 5 days postfeeding, appears to stop using gluconeogenic nutrients thereafter in a large, long-term colonization niche, but continues to use them in a smaller niche to compete with invading E. coli EDL933. Evidence is also presented suggesting that invading E. coli EDL933 uses both glycolytic and gluconeogenic nutrients and needs the ability to perform gluconeogenesis in order to colonize mice precolonized with E. coli Nissle 1917. The data presented here therefore rule out the possibility that E. coli Nissle 1917 can starve the O157:H7 E. coli strain EDL933 of gluconeogenic nutrients, even though E. coli Nissle 1917 uses such nutrients to compete with E. coli EDL933 in the mouse intestine
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