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Registros recuperados: 37 | |
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Rajoka,Muhammad Ibrahim; Khan,Sana. |
Production of β-xylosidaseby a cycloheximide and 2-deoxy-D-glucose-resistant mutant of Kluyveromyces marxianus PPY125 was studied when cultured on growth media containing galactose, glucose, xylose, cellobiose, sucrose and lactose as carbon sources. Xylose, cellobiose, lactose and sucrose were the key substrates. Both K. marxianus PPY125 and its mutant (M 125) supported maximum β-xylosidase specific product yield (Y P/X) following growth on xylose. Basal level of activity was observed in non-induced cultures grown on glucose. The mutant produced 1.5 to 2-fold more β-xylosidase than that produced by the wild cells. Synthesis of β-xylosidase was regulated by an induction mechanism in both wild and mutant cells. Addition of... |
Tipo: Journal article |
Palavras-chave: Enthalpy; Entropy; Enzyme kinetics; Fermentation; Induction; Thermodynamics. |
Ano: 2005 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582005000200007 |
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Fernandes,Francely M.; Lapola,David M.; Neregato,Rodrigo; Carvalho,Marcelo H. de; Von Zuben,Claudio J.. |
Lucilia cuprina (Wiedemann, 1830) is a cosmopolite blowfly species of medical and veterinary importance because it produces myiasis, mainly in ovine. In order to evaluate the demographic characteristics of this species, survivorship curves for 327 adult males and 323 adult females, from generation F1 maintained under experimental conditions, were obtained. Entropy was utilized as the estimator of the survival pattern to quantify the mortality distribution of individuals as a function of age. The entropy values 0.216 (males) and 0.303 (females) were obtained. These results denote that, considering the survivorship interval until the death of the last individual for each sex, the males present a tendency of mortality in more advanced age intervals, in... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Survivorship curve; Entropy; Lucilia; Calliphoridae. |
Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212003000300010 |
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Preckel, Paul V.. |
Mathematical measures of entropy as defined by Shannon (1948) and Kullback and Leibler (1951) are currently in vogue in the field of econometrics, primarily due to the comprehensive work by Golan, Judge, and Miller (1996). In this paper, an alternative interpretation of the entropy measure as a penalty function over deviations is presented. Using this interpretation, a number of parallels are drawn with least squares estimators, and it is demonstrated that, with a minor modification of the traditional least squares estimator, both approaches may be applied to the general linear model. The advantages and disadvantages of each approach are discussed, and a philosophical approach to the selection of estimation technique is suggested. |
Tipo: Working or Discussion Paper |
Palavras-chave: Entropy; Econometrics; Penalty functions; Estimation; Research Methods/ Statistical Methods. |
Ano: 1998 |
URL: http://purl.umn.edu/28625 |
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Rios, Ana R.; Gray, Allan W.. |
This study examines rate of concentration of farms and sales for aggregate farm production and crop and livestock activities during the 1982 to 2002 period. Data from the Census of Agriculture are used to calculate Theil's relative entropy measure as an indicator of concentration. Results indicate that Grain segments are lagging behind cotton, potato and hog segments in terms of concentration of total sales, while concentration in the dairy segment appears to be gaining steam. Agribusiness serving less concentrated industry segments should look to the more concentrated segments as leading indicators for effective marketing strategies as concentration increases. |
Tipo: Conference Paper or Presentation |
Palavras-chave: Concentration; Commodities; Entropy; Agribusiness. |
Ano: 2005 |
URL: http://purl.umn.edu/19136 |
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Taylor, Timothy G.; Francis, Brian. |
Agriculture, in general, and agricultural exports in particular, have long been critical to economic growth and development in Latin America and the Caribbean (LAC). Despite the importance of agriculture to the region and the vast amount of resources devoted to the promotion of agricultural export diversification in LAC, there has been virtually no research undertaken to assess the degree to which the agricultural export structures in LAC countries have in fact diversified. Using disaggregate data on agricultural exports over the 1961-2000 period for 10 LAC countries, entropy-based measures of diversification are computed and analyzed. The empirical results show that the post-1985 period has witnessed some degree of agricultural export diversification... |
Tipo: Journal Article |
Palavras-chave: Agriculture; Caribbean; Diversification; Entropy; Exports; Latin America. |
Ano: 2003 |
URL: http://purl.umn.edu/43284 |
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Hubbell, Bryan J.; Welsh, Rick. |
Geographic concentration in U.S. hog production from 1974-96 is investigated using a measure based on Theil's entropy index. For the U.S. as a whole, geographic concentration is occurring at a slow rate, both for hog farms and hog numbers. However, for particular states, primarily in the new Southern Atlantic production region, concentration is high and increasing at a rapid pace. Concentration was increasing for the 23-year period for 16 out of the 20 states in the analysis. Results indicate that geographic concentration by augmentation is occurring to the greatest degree in Arkansas, Missouri, North Carolina, Oklahoma, and Pennsylvania. |
Tipo: Journal Article |
Palavras-chave: Entropy; Geographic concentration; Hog production; Livestock Production/Industries. |
Ano: 1998 |
URL: http://purl.umn.edu/15566 |
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Aiginger, Karl; Davies, Stephen W.. |
Some recent studies have shown that specialisation of countries has tended to increase, while regional concentration of countries has tended to decrease. This seems to be counterintuitive at first glance. In this paper, we use the entropy index - as the indicator of structural change with the neatest aggregation properties to show how this divergence can happen. The main purpose of the paper is methodological, but we also apply the methodology to a specific case study: Manufacturing in the European Union since 1985. We confirm for this interesting period that increasing industrial specialisation has been offset by faster growth in the smaller Member States, with the net effect that industries have become somewhat less geographically concentrated. In terms... |
Tipo: Journal Article |
Palavras-chave: Structural change; Geographical concentration; Industrial specialisation; European integration; Entropy; F02; F15; L60. |
Ano: 2004 |
URL: http://purl.umn.edu/37627 |
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Gocht, Alexander. |
When building an economic model for supply analysis the aim is to model a decision making process of one or more agents which fits the observed practice as good as possible. Hereby the modeller is often confronted with incomplete information about the production process; particular crop specific input data are rarely available. The problem of defining activity related technology inputs coefficients is not new. A good deal of literature comes from the mathematical programming perspective, where input coefficients were estimated using a standard linear regression function to fully represent the mathematical program. However this approach is a pure technical device and may result in an inconsistent model. The author of the paper wants to investigate whether... |
Tipo: Conference Paper or Presentation |
Palavras-chave: Farm supply model; Input allocation; Entropy; HDP; Research Methods/ Statistical Methods. |
Ano: 2008 |
URL: http://purl.umn.edu/6469 |
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Beaton, Aaron J.; Dhuyvetter, Kevin C.; Kastens, Terry L.; Williams, Jeffery R.. |
With increasingly thin margins and new technologies, it is important that farm managers know their cost of field operations on a per unit basis (e.g., acre, ton, bale). Accurate per unit costs give confidence when constructing enterprise budgets and evaluating new technologies, such as no-till. Custom rates are often used as a proxy for per unit costs; however, this research, using entropy and jackknife estimation procedures, found that custom rates understate total ownership and operating costs by approximately 25% for an average Kansas farm. Estimates from these models are then used to benchmark actual costs against expected cost. |
Tipo: Journal Article |
Palavras-chave: Benchmark; Custom rates; Custom work; Entropy; Jackknife; Machinery costs; Production Economics; Productivity Analysis; Q10; Q12; C51; C60. |
Ano: 2005 |
URL: http://purl.umn.edu/43720 |
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Registros recuperados: 37 | |
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