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Diminishing returns in agriculture historical and critical sketch /McNall, Preston Essex, January 1932 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1932. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
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Some methods of estimating fertilizer response functions for refinement of diminishing returns analysisKawakatsu, Shōhei. January 1957 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1957. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 174-180).
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The use of factor mixture modeling to investigate population heterogeneity in hierarchical models of intelligenceReynolds, Matthew Robert 13 September 2012 (has links)
Spearman’s law of diminishing returns (SLODR) posits that at higher levels of general cognitive ability, the general factor (g) performs less well in explaining individual differences in cognitive test performance. The present study used factor mixture modeling to investigate SLODR in the Kaufman Assessment Battery for Children--Second Edition (KABC-II). Factor mixture modeling was a useful method to study SLODR because group membership was determined based on probabilities derived from the model. A second-order confirmatory factor model, consistent with three-stratum theory (Carroll, 1993), was modeled as a within-class factor structure. The fit of several models with varying number of classes and factorial invariance restrictions were compared. A sex covariate was also included with the models that provided the best fit for the data. The results indicated that a two-class model, which allowed for g mean differences, and class-specific g variances and subtest residual variances, provided the most parsimonious explanation of the data. Consistent with SLODR, the second-order general factor explained less subtest variance and less variance in the first-order factors for those of higher general ability. The standardized subtest residual variances were also larger in the high ability class than in the low ability class. Controlling for g, boys performed higher than girls in visual-spatial ability in each of the low and high ability classes. The findings from this study have implications for future research on the interpretation of intelligence test scores across the ability distribution. / text
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The use of factor mixture modeling to investigate population heterogeneity in hierarchical models of intelligenceReynolds, Matthew Robert. January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.
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Rações formuladas por meio da programação linear e não linear para poedeiras comerciais / Diets formulated by linear and nonlinear programming for commercial laying hensAlmeida, Thiago William de 29 July 2016 (has links)
Este trabalho foi conduzido com o objetivo de comparar a formulação de ração por meio da programação linear (custo mínimo) e programação não linear (lucro máximo) para poedeiras comerciais. Utilizou-se 288 poedeiras da linhagem Hisex® White de 33 a 45 semanas de idade, com 1,540 ± 0,1167 kg de peso corporal. As aves foram distribuídas em delineamento em blocos ao acaso, com seis tratamentos com seis repetições de oito aves cada, totalizando 36 parcelas. Os tratamentos experimentais foram: 1) ração de custo mínimo com exigências nutricionais das Tabelas Brasileiras para Aves e Suínos; 2) ração de custo mínimo com as exigências nutricionais recomendadas pelo Manual da Linhagem; 3) ração de custo mínimo com exigências nutricionais obtidas de modelos matemáticos para otimização de desempenho; 4) ração de lucro máximo em cenário de mercado normal; 5) ração de lucro máximo em cenário de mercado favorável; e 6) ração de lucro máximo em cenário de mercado desfavorável. O desempenho foi avaliado por meio do consumo de ração, produção de ovos, peso dos ovos, massa de ovos e conversão alimentar. Na qualidade interna e externa, em quatro ovos por parcela, foram avaliadas o peso do ovo, gravidade específica, resistência à quebra da casca, peso da casca, espessura da casca, coloração da gema, altura de albúmen e unidade Haugh. Para avaliação econômica calculou-se o lucro. Os dados foram submetidos a análise de variância e em caso de significância (P<0,05) foi aplicado o teste de Scott-Knott (5%). Não houve diferença estatística (P>0,05) para a unidade Haugh, altura do albúmen e para as características de qualidade externa de ovos. Verificou-se efeito de tratamento (P<0,05) nas características de desempenho e qualidade de ovos por meio do valor absoluto e relativos de albúmen e gema. De forma geral, os tratamentos com as exigências obtidas pelos modelos matemáticos seguido das obtidas pelo manual da linhagem, ambos da programação linear, proporcionaram melhores resultados de desempenho, pois as rações foram nutricionalmente mais densas, no entanto, pioraram os resultados econômicos. Conclui-se que rações formuladas por meio de programação linear propiciaram as aves melhor desempenho, todavia, sem correspondente benefício econômico comparadas as rações formuladas por meio de programação não linear. / This study aimed to compares the feed formulation using linear (minimal cost) and non-linear (maximum profit) programming for commercial hens. Thus, 288 Hisex® white layer hens, from 33 to 45 weeks old, with 1,54 ± 0,12 kg of BWwere used. The hens were distributed in randomized blocks, with six treatments and six replicates with eight birds per replicate, totaling 36 plots. The treatments were: 1) minimum cost feed formulation, with nutritional requirements proposed by Rostagno et al. (2011); 2) minimum cost feed formulation, with nutritional requirements recommended by strain management guide; 3) minimum cost feed formulation, with nutritional requirements obtained from mathematical models for performance optimization; 4) maximum profit feed formulation in normal market scenario; 5) maximum profit feed formulation in favorable market scenario; and 6) maximum profit feed formulation in an unfavorable market scenario. The performance was evaluated from feed intake, egg production, egg weight, egg mass and feed conversion ratio. In four eggs per pen was evaluated the internal and external egg quality: egg weight, specific gravity, shell resistance, shell weight, shell thickness, yolk color, albumen height and Haugh unit. To economic evaluation, profit was calculated. Data were submitted to variance analyses and when significant (P<0.05) Scott-Knott test (5%) was applied. There was no statistical difference (P>0.05) for Haugh unit, albumen height and external quality of the eggs. There was effect of treatment (P<0.05) on performance and eggs quality from absolute and relative values of yolk and albumen. In general, treatments with requirements obtained by mathematical models or by strain management guide, both from linear programming, improved the performance results, since diets were denser nutritionally, however, worsened the economic results. In summary, feed formulated by linear programming improves performance, however, worsens economic results compared with nonlinear programming.
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Rações formuladas por meio da programação linear e não linear para poedeiras comerciais / Diets formulated by linear and nonlinear programming for commercial laying hensThiago William de Almeida 29 July 2016 (has links)
Este trabalho foi conduzido com o objetivo de comparar a formulação de ração por meio da programação linear (custo mínimo) e programação não linear (lucro máximo) para poedeiras comerciais. Utilizou-se 288 poedeiras da linhagem Hisex® White de 33 a 45 semanas de idade, com 1,540 ± 0,1167 kg de peso corporal. As aves foram distribuídas em delineamento em blocos ao acaso, com seis tratamentos com seis repetições de oito aves cada, totalizando 36 parcelas. Os tratamentos experimentais foram: 1) ração de custo mínimo com exigências nutricionais das Tabelas Brasileiras para Aves e Suínos; 2) ração de custo mínimo com as exigências nutricionais recomendadas pelo Manual da Linhagem; 3) ração de custo mínimo com exigências nutricionais obtidas de modelos matemáticos para otimização de desempenho; 4) ração de lucro máximo em cenário de mercado normal; 5) ração de lucro máximo em cenário de mercado favorável; e 6) ração de lucro máximo em cenário de mercado desfavorável. O desempenho foi avaliado por meio do consumo de ração, produção de ovos, peso dos ovos, massa de ovos e conversão alimentar. Na qualidade interna e externa, em quatro ovos por parcela, foram avaliadas o peso do ovo, gravidade específica, resistência à quebra da casca, peso da casca, espessura da casca, coloração da gema, altura de albúmen e unidade Haugh. Para avaliação econômica calculou-se o lucro. Os dados foram submetidos a análise de variância e em caso de significância (P<0,05) foi aplicado o teste de Scott-Knott (5%). Não houve diferença estatística (P>0,05) para a unidade Haugh, altura do albúmen e para as características de qualidade externa de ovos. Verificou-se efeito de tratamento (P<0,05) nas características de desempenho e qualidade de ovos por meio do valor absoluto e relativos de albúmen e gema. De forma geral, os tratamentos com as exigências obtidas pelos modelos matemáticos seguido das obtidas pelo manual da linhagem, ambos da programação linear, proporcionaram melhores resultados de desempenho, pois as rações foram nutricionalmente mais densas, no entanto, pioraram os resultados econômicos. Conclui-se que rações formuladas por meio de programação linear propiciaram as aves melhor desempenho, todavia, sem correspondente benefício econômico comparadas as rações formuladas por meio de programação não linear. / This study aimed to compares the feed formulation using linear (minimal cost) and non-linear (maximum profit) programming for commercial hens. Thus, 288 Hisex® white layer hens, from 33 to 45 weeks old, with 1,54 ± 0,12 kg of BWwere used. The hens were distributed in randomized blocks, with six treatments and six replicates with eight birds per replicate, totaling 36 plots. The treatments were: 1) minimum cost feed formulation, with nutritional requirements proposed by Rostagno et al. (2011); 2) minimum cost feed formulation, with nutritional requirements recommended by strain management guide; 3) minimum cost feed formulation, with nutritional requirements obtained from mathematical models for performance optimization; 4) maximum profit feed formulation in normal market scenario; 5) maximum profit feed formulation in favorable market scenario; and 6) maximum profit feed formulation in an unfavorable market scenario. The performance was evaluated from feed intake, egg production, egg weight, egg mass and feed conversion ratio. In four eggs per pen was evaluated the internal and external egg quality: egg weight, specific gravity, shell resistance, shell weight, shell thickness, yolk color, albumen height and Haugh unit. To economic evaluation, profit was calculated. Data were submitted to variance analyses and when significant (P<0.05) Scott-Knott test (5%) was applied. There was no statistical difference (P>0.05) for Haugh unit, albumen height and external quality of the eggs. There was effect of treatment (P<0.05) on performance and eggs quality from absolute and relative values of yolk and albumen. In general, treatments with requirements obtained by mathematical models or by strain management guide, both from linear programming, improved the performance results, since diets were denser nutritionally, however, worsened the economic results. In summary, feed formulated by linear programming improves performance, however, worsens economic results compared with nonlinear programming.
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Modelos de regressão e curvas de produção vegetal: aplicações nas áreas de nutrição mineral de plantas e adubação / Regression models and yield curves: with applications in plant mineral nutrition and fertilizationFerreira, Iuri Emmanuel de Paula 15 June 2015 (has links)
A avaliação do estado nutricional das culturas requer o uso de padrões para comparação, tais como os níveis críticos e as faixas de suficiência. Esses padrões de interesse agrícola geralmente são estimados a partir da curva de calibração da produção vegetal, que relaciona os rendimentos de uma cultura com a dose do adubo aplicada no solo ou com o teor de algum elemento nos tecidos. A curva de produção vegetal é fundamental para o desenvolvimento de pesquisas nas áreas de nutrição mineral de plantas e adubação, uma vez que o conhecimento a seu respeito possibilita o uso econômico de adubos e a elaboração de estratégias corretivas para o solo. No entanto, a curva de produção divide-se em diferentes regimes nutricionais, que lhe conferem uma forma peculiar e dificultam sua descrição matemática. O objetivo desse trabalho é a construção de modelos de regressão flexíveis, capazes de descrever adequadamente a curva de produção vegetal. Em uma primeira abordagem, modelos lineares segmentados com transições de fase suaves são usados para descrever a produção do trigo de inverno em função da adubação com nitrogênio. Por meio dos ajustes destes modelos, também são estimados os níveis críticos e as faixas de suficiência. Posteriormente, realiza-se a modelagem matemática da resposta vegetativa à adubação, desconsiderando doses tóxicas. Observa-se que cada tipo possível de resposta vegetativa é ligado de forma unívoca a uma função de produção agrícola. A técnica proposta, além de permitir a construção de novas funções de produção, fornece interpretações fisiológicas claras para parâmetros de alguns modelos de uso comum na agricultura. Com base na segunda abordagem, um novo enunciado para a lei de Mitscherlich é apresentado: quanto maior é o conteúdo total do nutriente limitante na planta, menor é o aproveitamento feito (a fim de lhe prover crescimento) de um incremento em sua disponibilidade - como consequência, os retornos da adubação são decrescentes. / The evaluation of the plant nutritional status requires standards for comparisons, such as the critical levels and sufficiency ranges. These standards are generally estimated by means of the yield curves in response to fertilizers, which relates production with doses applied or nutrient content in the plant tissues. The yield curve is essential for the development of researches on plant mineral nutrition and fertilization, since knowledge of this curve allows economic use of fertilizers and planning strategies for soil correction. However, the production curve is divided into different nutritional regimes, which give it a peculiar shape and hinders its mathematical description. In this work, the objective is to build flexible regression models, able to adequately describe the yield curves. In a first approach, linear piecewise models with smooth transitions between regimes are used to describe the winter-wheat yield in function of the nitrogen doses. By means of the fits of these models, the critical levels and sufficiency ranges are also estimated. In another approach, it is proposed a mathematical model for yield response (or returns) from fertilizers - toxic doses are neglected in this phase. It is verified that each possible yield response type is uniquely related with a production function. This approach allows to construct new production functions and, indeed, provides clear physiological interpretations for the parameters of some common models in agriculture. Based on the second approach, it is presented a new statement for the Mitscherlich law: the greater is the total content of the limiting nutrient in the plant, the lower is the exploited fraction (in order to provide growth) of an increment in its availability - as a consequence, the returns from fertilization are diminishing.
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Eficiência marginal da lisina digestível das dietas para suínos em crescimento e terminação : um estudo meta-analítico / Marginal efficiency of digestible lysine diets for growing-finishing pigs : a meta-analytical studyMelchior, Raquel January 2016 (has links)
Inúmeros trabalhos avaliando as exigências de lisina podem ser encontrados na literatura, mas seus resultados são heterogêneos. Revisões sistemáticas e a meta-análise permitem integrar diferentes variáveis, gerar novos resultados e obter respostas ajustadas a uma maior diversidade experimental. Objetivou-se explorar as relações da lisina digestível com as variáveis de desempenho, estabelecer a exigência e avaliar a eficiência marginal da lisina segundo a lei de rendimentos decrescentes para suínos em crescimento e terminação. Para os estudos I e II, foram compilados 36 artigos publicados entre 2002 e 2013 avaliando 2.399 suínos pesando entre 15-120 kg. Para o estudo III, foram utilizados 26 artigos que avaliaram 1.820 suínos pesando entre 20-120 kg. No estudo I, o consumo diário de lisina apresentou correlações maiores com a ingestão de energia metabolizável e proteína bruta e com as deposições de proteína e lipídios. O consumo diário de lisina apresentou melhor ajuste nas equações de variância-covariância do que o nível percentual de lisina. No estudo II, o aumento no consumo diário de lisina melhorou o ganho de peso e a deposição de proteína na fase de 70-120 kg. Nas fases de 15-30; 30-70 e 70-120 kg os níveis de lisina digestível determinados para obter as melhores respostas de ganho corresponderam ao consumo diário de 14,8; 20,2 e 18,3 g lisina/dia. Os níveis de lisina digestível determinados para obter as melhores respostas de deposição de proteína corresponderam ao consumo diário de 16,3 e 24,1 g lisina/dia nas fases 15-30 e 30-70 kg. No estudo III, observamos que a medida que o animal se aproxima ou atinge o ponto de máximo desempenho, a eficiência de uso da lisina digestível diminui segundo a lei de rendimentos decrescentes. Dietas formuladas para atender 95% da máxima resposta de ganho de peso permitem uma melhora na eficiência marginal de uso da lisina da ordem de 2,4; 2,5 e 1,5 g de ganho de peso para cada g de lisina ingerida nas faixas de peso vivo 20-50; 50-70 e 70-120 kg. Sugerimos a inclusão de variáveis como a eficiência alimentar e o ganho de peso nas análises de determinação de exigências de lisina, também a escolha de metodologias analíticas adequadas e a inclusão da lei de rendimentos decrescentes da eficiência marginal de uso da lisina nos atuais modelos de determinação de exigência para evitar a superestimação observada nas tabelas de recomendação nutricional. / Several studies evaluating the lysine requirements are avaible in the literature, but its results are heterogeneous. Systematic reviews and meta-analysis allows integrating different variables, generating new results and producing answers adjusted to experimental diversity. This objective of this study was to explore the relationship among dietary lysine and the performance variables, establishing the requirement and assessing the marginal efficiency of dietary lysine according to the law of diminishing returns for growing-finishing pigs. For studies I and II, 36 articles published from 2002 to 2013 evaluating 2399 pigs weighing between 15-120 kg were compiled. And for the study III 26 articles evaluating 1820 pigs weighing between 20-120 kg were used. In the study I, daily intake of lysine showed higher correlations with the metabolizable energy intake and crude protein, with the protein deposition and lipid deposition. The daily intake of lysine showed better adjustment in the variance-covariance equations than the dietary level of lysine. In Study II, increasing the daily intake of lysine improved the weight gain and protein deposition in the 70-120 kg phase. In 15-30; 30-70 and 70-120 kg phase the levels digestible lysine that maximized weight gain reponse corresponded to the daily intake of 14.8; 20.2 and 18.3 g lysine/day. Lysine levels that maximized protein deposition reponse corresponded to daily intake of 16.3 and 24.1 g lysine/day in the phases 15-30 and 30-70 kg. In the study III, it was observed that, as the animal approaches or reaches the maximum performance the efficiency of lysine use decreases according to the law of diminishing returns. Diets formulated to meet 95% of the maximal weight gain response permit a marginal improvement in efficiency of use of the lysine the order of 2.4; 2.5 and 1.5 grams of weight gain for each lysine grams ingested in live weight phases 20-50; 50-70 and 70-120 kg respectively. It suggest the inclusion of variables feed efficiency and weight gain in analysis for the determination of lysine requirements, also the choice of appropriate analytical methods and the inclusion of diminishing returns law of marginal efficiency the dietary lysine in current models for the determination of requirements to avoid the overestimation observed in nutritional recommendation tables.
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An Analysis of the Surface Area of the Western Roman Empire until CE 476Roncone, Laura Antonia January 2012 (has links)
In 1968, Rein Taagepera created growth curves of four empires by measuring the surface area of each and plotting his data on a graph of area versus time. He used his growth curves to analyse the development of empires quantitatively, as he considered surface area to be the best measurable indicator of an empire’s strength. His growth curve of the Roman Empire, in particular, has been referenced numerous times by scholars researching the decline and fall of complex civilizations to support their individual analyses of the collapse of Rome. While this thesis surveys only the territories of the Western Roman Empire, many of the parameters used by Taagepera have been either borrowed or adapted in order to define, measure, and graph the surface area of the Western Empire as precisely as possible. This thesis also adds further precision and validity to Bryan Ward-Perkins’ theory that surface area can be used to analyse and quantify the collapse of a complex society accurately.
In order to demonstrate the extent to which differing circumstances and outcomes of provincial history impacted the total surface area of the Western Roman Empire, it was essential to include not only an overview of Rome’s extensive history, but also to establish the chronology, as it related to the Roman Empire, of each individual province, territory, and client kingdom within the Western Empire. Detailed chronologies of Noricum and Britannia have been included to serve as case studies as they comprise a broad range of distinct characteristics and so represent typical western provinces.
My research of the history and geography of the Roman Empire has generated a comprehensive inventory that includes all the pertinent onomastic and chronological data needed to measure the surface area of each of Rome’s western provinces and client kingdoms. When plotted on a graph of area versus time, my data not only produced an accurate representation of the actual surface area of the Western Roman Empire, but also one that facilitates temporal analyses of territorial fluctuations at any given point in the Empire’s history until the fall of the Western Empire in CE 476.
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An Analysis of the Surface Area of the Western Roman Empire until CE 476Roncone, Laura Antonia January 2012 (has links)
In 1968, Rein Taagepera created growth curves of four empires by measuring the surface area of each and plotting his data on a graph of area versus time. He used his growth curves to analyse the development of empires quantitatively, as he considered surface area to be the best measurable indicator of an empire’s strength. His growth curve of the Roman Empire, in particular, has been referenced numerous times by scholars researching the decline and fall of complex civilizations to support their individual analyses of the collapse of Rome. While this thesis surveys only the territories of the Western Roman Empire, many of the parameters used by Taagepera have been either borrowed or adapted in order to define, measure, and graph the surface area of the Western Empire as precisely as possible. This thesis also adds further precision and validity to Bryan Ward-Perkins’ theory that surface area can be used to analyse and quantify the collapse of a complex society accurately.
In order to demonstrate the extent to which differing circumstances and outcomes of provincial history impacted the total surface area of the Western Roman Empire, it was essential to include not only an overview of Rome’s extensive history, but also to establish the chronology, as it related to the Roman Empire, of each individual province, territory, and client kingdom within the Western Empire. Detailed chronologies of Noricum and Britannia have been included to serve as case studies as they comprise a broad range of distinct characteristics and so represent typical western provinces.
My research of the history and geography of the Roman Empire has generated a comprehensive inventory that includes all the pertinent onomastic and chronological data needed to measure the surface area of each of Rome’s western provinces and client kingdoms. When plotted on a graph of area versus time, my data not only produced an accurate representation of the actual surface area of the Western Roman Empire, but also one that facilitates temporal analyses of territorial fluctuations at any given point in the Empire’s history until the fall of the Western Empire in CE 476.
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