Sabiia Seb
PortuguêsEspañolEnglish
Embrapa
        Busca avançada

Botão Atualizar


Botão Atualizar

Ordenar por: 

RelevânciaAutorTítuloAnoImprime registros no formato resumido
Registros recuperados: 123
Primeira ... 1234567 ... Última
Imagem não selecionada

Imprime registro no formato completo
Managing multiple-use resources: optimizing reservoir water use for irrigation and fisheries AgEcon
Tran, Lap Doc; Schilizzi, Steven; Chalak, Morteza; Kingwell, Ross S..
Policy makers in Vietnam face difficult choices when deciding reservoir water management strategies between irrigation and fisheries. In this paper, an economic optimization model for water management is developed to facilitate policy makers' decision making. The model includes the response of rice and fish yields to key factors including reservoir water levels, the timing and quantity of water release, and climatic conditions. The model accounts for variation in rainfall patterns, irrigation requirements, and the demand for low water levels during the fish harvest season. The model is applied to the Daton reservoir in the south of Vietnam to maximize profits in each of three production scenarios where the reservoir's water is used for: (1) only producing...
Tipo: Conference Paper or Presentation Palavras-chave: Multiple-use resources; Reservoir water management; Optimization; Irrigation; Fisheries; And stochastic; Production Economics.
Ano: 2011 URL: http://purl.umn.edu/100721
Imagem não selecionada

Imprime registro no formato completo
Improved Program Planning Approaches Generates Large Benefits in High Risk Crop Farming AgEcon
Musshoff, Oliver; Hirschauer, Norbert.
This paper examines whether there is room for the improvement of farm program decisions through the incorporation of mathematical optimization in the practical planning process. Probing the potential for improvement, we investigate the cases of four German cash crop farms over the last six years. The formal planning approach includes a systematic time series analysis of farmspecific single gross margins and a stochastic optimization model. In order to avoid solutions that simply exceed the farmer’'s risk tolerance, the apparently accepted variance of the observed program’'s total gross margin which represents an observable reflection of the individual farmer'’s risk attitude is used as an upper bound in the optimization. For each of the 24 planning...
Tipo: Conference Paper or Presentation Palavras-chave: Production program planning; Optimization; Uncertainty; Static distributions; Stochastic processes; Crop Production/Industries; C1; C61; M11; Q12.
Ano: 2007 URL: http://purl.umn.edu/10442
Imagem não selecionada

Imprime registro no formato completo
Optimal Allocation of Reservoir Water AgEcon
Debnath, Deepayan; Stoecker, Arthur L.; Boyer, Tracy A.; Sanders, Larry D..
The purpose of this paper is to determine the optimal allocation of reservoir water among consumptive and non-consumptive uses. A non-linear mathematical programming model is developed to optimally allocate Lake Tenkiller water among competing uses that maximize the net social benefit. A mass balance is used to determine the level and volume of water in the lake. This paper examines the effect of water management on lake resources when recreational values are and are not included as control variables in the optimization process. Results show that maintaining the lake level to the ‘normal lake level’ of 632 feet during the summer months generates more recreational benefit rather than reducing the lake level by releasing water for hydro power generation.
Tipo: Conference Paper or Presentation Palavras-chave: Consumptive and non-consumptive use; Mass balance equation; Non-linear mathematical programming; Optimization; Recreational uses; Water allocation; Resource /Energy Economics and Policy.
Ano: 2009 URL: http://purl.umn.edu/46842
Imagem não selecionada

Imprime registro no formato completo
Optimierung unter Unsicherheit mit Hilfe stochastischer Simulation und Genetischer Algorithmen – dargestellt anhand der Optimierung des Produktionsprogramms eines Brandenburger Marktfruchtbetriebes AgEcon
Musshoff, Oliver; Hirschauer, Norbert.
Optimization has been recognized as a powerful tool in teaching and research for a long time. In spite of its well known problem solving capacity, some methodological obstacles have persisted over the years. The main problem is that stochastic variables and their correlations cannot be adequately accounted for within traditional optimization procedures. In this paper, we develop a methodological mix of stochastic simulation and a heuristic optimization procedure which has become known as genetic algorithms. The simulation part of the mix allows for the consideration of complex information such as stochastic processes; the genetic algorithms-part ensures that the method remains manageable in terms of required time and resources. We demonstrate the decision...
Tipo: Journal Article Palavras-chave: Optimization; Optimal production program; Stochastic simulation; Genetic algorithms; Uncertainty; Stochastic processes; Farm Management; Risk and Uncertainty.
Ano: 2004 URL: http://purl.umn.edu/97454
Imagem não selecionada

Imprime registro no formato completo
Bacterial Resistance and the Optimal Use of Antibiotics AgEcon
Laxminarayan, Ramanan.
The increasing resistance of harmful biological organisms (bacteria, parasites, and pests) to selection pressure from the widespread use of control agents such as antibiotics, antimalarials, and pesticides is a serious problem in both medicine and agriculture. Modeling resistance-or, conversely, the effectiveness of these control agents as a biological resource-yields insights into how these agents should be optimally managed to maximize their economic benefit to society. This paper uses a model of evolution of bacterial resistance to antibiotics-in which resistance places an evolutionary disadvantage on the resistant organism-to develop a simple sequential algorithm of optimal antibiotic use. Although the solution to this problem follows the...
Tipo: Working or Discussion Paper Palavras-chave: Antibiotic resistance; Natural resource; Optimization; Health Economics and Policy; I0; Q0.
Ano: 2001 URL: http://purl.umn.edu/10479
Imagem não selecionada

Imprime registro no formato completo
A Watershed-Based Economic Model of Alternative Management Practices in Southern Agricultural Systems AgEcon
Paudel, Krishna P.; Hite, Diane; Intarapapong, Walaiporn; Susanto, Dwi.
We investigated the environmental impacts of alternative cultural practices within a watershed under different water quality standards. We used experimental data on nutrient runoff to determine the optimal amount of broiler litter application in hay production in Louisiana. To compensate for the lack of experimental data, we used biophysical simulation models to find the optimal combination of agricultural best-management practices in a watershed in Mississippi. The results indicated that stricter environmental standards lower total profit potential and litter utilization.
Tipo: Journal Article Palavras-chave: Broiler litter; Cropping systems; Optimization; Watershed level modeling; Water quality; C6; Q1; Q25; D21.
Ano: 2003 URL: http://purl.umn.edu/43213
Imagem não selecionada

Imprime registro no formato completo
Biological Limits on Agricultural Intensification: An Example from Resistance Management AgEcon
Laxminarayan, Ramanan; Simpson, R. David.
When the application of pesticides places selective evolutionary pressure on pest populations, it can be useful to plant refuge areas-crop areas intended to encourage the breeding of pests that are susceptible to the pesticide. Renewed interest in refuge areas has arisen with recent advances in biotechnology and genetically modified (GM) crops. In this paper, we use a simple model of the evolution of pest resistance to characterize the socially optimal refuge strategy for managing pest resistance. We demonstrate some interesting analogies with other models of renewable resource management, such as those of fisheries. Among the analogous results are findings that maintaining what we might call "maximal sustainable susceptibility" is typically not...
Tipo: Working or Discussion Paper Palavras-chave: Pest resistance; Biotechnology; Optimization; Research and Development/Tech Change/Emerging Technologies; Q1; Q2.
Ano: 2000 URL: http://purl.umn.edu/10914
Imagem não selecionada

Imprime registro no formato completo
Avaliação da viabilidade técnica e econômica da utilização de biomassas como fonte energética alternativa em fornos industriais AgEcon
Lima, Lilian Maluf de; Oliveira, Ana Maria Kefalas; Carletti, Paulo de Tarso Filho; Ferrari, Renata Cristina; Caixeta, Jose Vicente Filho.
This study, conducted along the year 2003, was held in the environment of a cement company plant located in the São Paulo State. That industry has used carbon black as predominant energetic source which besides resulting a huge emission of gases (CO and CO2) into the atmosphere, has been more expensive than some other alternatives of biomass sources. Taking into consideration the location of that plant, there was a large supply of available biomass to be used as alternative fuel for industrial ovens. Several biomasses were analyzed and it was concluded that the sugar cane bagasse and residues of wood (sawdust and woodchips) were the most appropriate alternatives to such an industry.
Tipo: Journal Article Palavras-chave: Biomass; Energy; Transport; Optimization; Resource /Energy Economics and Policy.
Ano: 2006 URL: http://purl.umn.edu/55310
Imagem não selecionada

Imprime registro no formato completo
Adjustment of mathematical models and quality of soybean grains in the drying with high temperatures AGRIAMBI
Coradi,Paulo C.; Fernandes,Carlos H. P.; Helmich,Jean C..
ABSTRACT The aim of this study was to evaluate the influence of the initial moisture content of soybeans and the drying air temperatures on drying kinetics and grain quality, and find the best mathematical model that fit the experimental data of drying, effective diffusivity and isosteric heat of desorption. The experimental design was completely randomized (CRD), with a factorial scheme (4 x 2), four drying temperatures (75, 90, 105 and 120 ºC) and two initial moisture contents (25 and 19% d.b.), with three replicates. The initial moisture content of the product interferes with the drying time. The model of Wang and Singh proved to be more suitable to describe the drying of soybeans to temperature ranges of the drying air of 75, 90, 105 and 120 °C and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Dimensioning; Optimization; Post-harvest..
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000400385
Imagem não selecionada

Imprime registro no formato completo
Valorization of sunflower meal through the production of ethanol from the hemicellulosic fraction AGRIAMBI
Tavares,Bruna; Sene,Luciane; Christ,Divair.
ABSTRACT Sunflower is among the major oil seeds crop grown in the world and the by-products generated during the seeds processing represent an attractive source of lignocellulosic biomass for bioprocesses. The conversion of lignocellulosic fibers into fermentable sugars has been considered as a promising alternative to increase the demand for ethanol. The present study aimed to establish the fermentation conditions for ethanol production by Scheffersomyces stipitis ATCC 58376 in sunflower meal hemicellulosic hydrolysate, through a 23 CCRD (Central Composite Rotational Design) factorial design. Under the selected conditions (pH 5.25, 29 ºC and 198 rpm) the final ethanol concentration was 13.92 g L-1 and the ethanol yield was 0.49 g g-1.
Tipo: Info:eu-repo/semantics/article Palavras-chave: By-product; Biomass; Xylose; Biofuel; Optimization.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016001101036
Imagem não selecionada

Imprime registro no formato completo
Nitrogen efficiency in oats on grain yield with stability AGRIAMBI
Silva,José A. G. da; Goi Neto,Constantino J.; Fernandes,Sandra B. V.; Mantai,Rubia D.; Scremin,Osmar B.; Pretto,Rafael.
ABSTRACT Nitrogen (N) is the nutrient most absorbed by the oat crop. Unfavorable climate conditions decrease its efficiency, generating instability and reduction in yield. The objective of this study was to improve N use efficiency in oat grain yield by the economic value of the product and of the input and by models that scale the stability, considering systems of succession of high and reduced residual-N release in favorable and unfavorable years for cultivation. The study was conducted in the years 2013, 2014 and 2015 in two systems of succession (soybean/oat, maize/oat) in randomized blocks with eight replicates, using the N-fertilizer doses of 0, 30, 60 and 120 kg ha-1. The N-fertilizer dose for maximum economic efficiency in oats should be considered...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Avena Sativa; C/N; Predictability; Biometric models; Optimization.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016001201095
Imagem não selecionada

Imprime registro no formato completo
Physiological quality of soybean seeds under different yield environments and plant density AGRIAMBI
Baron,Felipe A.; Corassa Junior,Geomar M.; Fioresi,Dejales; Santi,Antônio L.; Martini,Renan T.; Kulczynski,Stela M..
ABSTRACT Yield potential of agricultural fields associated with plant spatial arrangement could determine the physiological quality of soybean (Glycine max L.) seeds. Thus, this study aimed to evaluate the physiological quality of soybean seeds from different yield environments and plant densities. Experiments were carried out in Boa Vista das Missões-RS, Brazil, during the 2014/2015 growing season. Yield environments were delineated by overlapping yield maps from the 2008, 2009/2010 and 2011/2012 growing seasons. The experimental design was a randomized complete block in a 2 x 5 factorial arrangement with two yield environments (low and high) and five plant densities, with four replicates. Two varieties were tested: Brasmax Ativa RR (10, 15, 20, 25 and 30...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Glycine max (L.); Seed vigor; Yield maps; Optimization.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000400237
Imagem não selecionada

Imprime registro no formato completo
Optimum contribution selection using differential evolution R. Bras. Zootec.
Carvalheiro,Roberto; Queiroz,Sandra Aidar de; Kinghorn,Brian.
A program to determine optimum contribution selection using differential evolution was developed. The objective function to be optimized was composed by the expected merit of the future progeny and the coancestry among selected parents. Simulated and real datasets of populations with overlapping generations were used to validate and test the performance of the program. The program was computationally efficient and feasible for practical applications. The expected consequences of using the program, in contrast to empirical procedures to control inbreeding and/or to selection based exclusively on expected genetic merit, would be the improvement of the selection response and a more effective control of inbreeding.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Evolutionary algorithms; Genetic response; Inbreeding; Optimization; Selection.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982010000700005
Imagem não selecionada

Imprime registro no formato completo
Estimate of the optimal level of concentrates for dairy cows on tropical pastures by using the concept of marginal analysis R. Bras. Zootec.
Oliveira,André Soares de; Campos,José Maurício de Souza; Lana,Rogério de Paula; Detmann,Edenio; Valadares Filho,Sebastião de Campos.
It was adopted in this work a methodology to estimate the optimal level of concentrate food for dairy cows on tropical pastures based on the theory of marginal analysis. An empiric model was developed and validated for application of the methodology using a database composed of 62 means of treatments from 32 studies in which milk production was evaluated regarded to the levels of concentrate feeding. Milk production (MP) showed quadratic behavior in response to concentrate intake (CI): MP (kg/cow/day) = 10.554 + 1.5855CI - 0.0552CI². Evaluation of the MP values observed over the predicted ones pointed the non-rejection of the null hypothesis, indicating that the model can be applied on the prediction of milk production, and consequently, on the optimal...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Marginal production response; Milk production; Modeling; Optimization.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982010000900024
Imagem não selecionada

Imprime registro no formato completo
A simplified Excel® algorithm for estimating the least limiting water range of soils Scientia Agricola
Leão,Tairone Paiva; Silva,Alvaro Pires da.
The least limiting water range (LLWR) of soils has been employed as a methodological approach for evaluation of soil physical quality in different agricultural systems, including forestry, grasslands and major crops. However, the absence of a simplified methodology for the quantification of LLWR has hampered the popularization of its use among researchers and soil managers. Taking this into account this work has the objective of proposing and describing a simplified algorithm developed in Excel® software for quantification of the LLWR, including the calculation of the critical bulk density, at which the LLWR becomes zero. Despite the simplicity of the procedures and numerical techniques of optimization used, the nonlinear regression produced reliable...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Nonlinear regression; Spreadsheet software; Optimization; Soil physics; Soil quality.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000600013
Imagem não selecionada

Imprime registro no formato completo
Mathematical tool to size rural digesters Scientia Agricola
Florentino,Helenice de Oliveira.
Anaerobic digesters have been highlighted due to the current energy crisis and its consequent search for alternative energy sources, allied to the intense process of livestock farming and agriculture modernization, which besides demanding a lot of energy, produces a great amount of crop and animal residues, most of the times generating sanitary problems. The aim of this work is to provide a mathematical tool to establish parameters for projects of construction of rural digesters, considering the response to energy demand, the suitability of the dimensions of the systems, yield factors and the guarantee of functionality. Non-linear optimization models, of easy resolution, for the three main types of rural digesters were formulated in this way. With the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Mathematical model; Optimization; Parameters for designing.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162003000100028
Imagem não selecionada

Imprime registro no formato completo
On the controlling of temperature: A proposal for a real-time controller in broiler houses Scientia Agricola
Detsch,Denise Trevisoli; Conti,Dante; Diniz-Ehrhardt,Maria Aparecida; Martínez,José Mario.
ABSTRACT: Environmental conditions in broiler houses, specifically temperature, are key factors that should be controlled to ensure appropriate environment for broiler rearing. In countries with tropical/subtropical climate, like Brazil, high temperatures produce heat stress to animals, affecting the production process. This research proposes a real-time model to control temperature inside broiler houses. The controller is a self-correcting model that makes real-time decisions on the ventilation system operation (exhaust fans) together with temperature prediction at the facility. The model involves partial differential equations (PDE) whose parameters are updated according to data registered in real-time. Some experiments were carried out at a pilot farm...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Partial differential equations (PDE); Temperature control; Optimization; Self-correcting model; Ventilation systems.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162018000600445
Imagem não selecionada

Imprime registro no formato completo
Formulation optimization and consumer acceptance of Peanut Sauce Thai Agricultural
Ruchikachorn, N.; Chompreeda, P.; Haruthaithanasan, V..
Palavras-chave: Formulation; Optimization; Consumer; Acceptance; Peanut; Sauce.
Ano: 2005 URL: http://anchan.lib.ku.ac.th/agnet/handle/001/4906
Imagem não selecionada

Imprime registro no formato completo
Optimization and consumer acceptability of calorie-reduced butter cake prepared from Thai jasmine rice Thai Agricultural
Chompreeda, P.; Suwonsichon, T.; Haruthaithanasan, V..
Palavras-chave: Optimization; Consumer; Acceptability; Cake; Rice.
Ano: 2005 URL: http://anchan.lib.ku.ac.th/agnet/handle/001/4902
Imagem não selecionada

Imprime registro no formato completo
Optimization and extrusion behavior on functional ready-to-eat breakfast cereal Thai Agricultural
Chulaluck Charunuch; Nipat Limsangouan; Waraporn Prasert; Pisut Butsuwan.
Tipo: PhysicalObject Palavras-chave: Extrusion; Mixed vegetable powders; Optimization; Ready to eat cereal breakfast; Breakfast; Cereal; อาหารเช้าธัญพืชพร้อมรับประทาน; กระบวนการเอกซ์ทรูชัน; แป้งผัก; คุณสมบัติทางกายภาพ; คุณสมบัติเชิงหน้าที่.
Ano: 2010 URL: http://anchan.lib.ku.ac.th/agnet/handle/001/5259
Registros recuperados: 123
Primeira ... 1234567 ... Última
 

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Embrapa
Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco

Valid HTML 4.01 Transitional