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Registros recuperados: 123 | |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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Registros recuperados: 123 | |
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