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Biotechnological induction of shikimate-based antioxidant accumulation in Phyla dulcis
No full textBackground: Medicinal phytochemicals have been used as dietary supplements in Asia and Africa for thousands of years. Biologically active antioxidants are very diverse and low in their chemical compositions thereby limiting their efficacies. The present study focuses on the enhanced accumulation of closely related dietary antioxidants: shikimate, quinate, salicylate and tocopherol in Phyla dulcis, the Central American herb known for its anti-inflammatory medicinal properties; but its polyphenolic antioxidants had not been studied. Methods: Phyla dulcis stem cuttings were planted in the greenhouse, and in field plots and treated with solutions of stoichiometric mixes of mineral salts known to double crop biomass and yield. Controls were treated with water. At maturity, P. dulcis shoots and flowers were harvested per treatment, immediately frozen in liquid nitrogen, and submitted to metabolomic analyses by gas chromatography-time-of-flight mass spectrometry. Results: Field plot P. dulcis treated with KKS-mineral salts combination induced increased shikimate accumulation of 1.59 g per 100 g from the 0.799 g per 100 g in the untreated control. Similarly salicylate, quinate, and tocopherols increased in accumulation by many orders of magnitude in the stoichiometric mixes of mineral salts-treated P. dulcis compared with the untreated controls. Conclusion: The accumulated polyphenolic antioxidants permitted the deduction of the unique biosynthetic pathway of the shikimate, with a massive inhibition at the enzyme steps of dehydroquinate dehydratase and shikimate dehydrogenase
Potential climate change impacts on citrus water requirement across major producing areas in the world
No full textUnderstanding how potential climate change will affect availability of water resources for citrus production globally is needed. The main goal of this study is to investigate impacts of potential future climate change on citrus irrigation requirements (IRR) in major global citrus producing regions, e.g., Africa, Asia, Australia, Mediterranean, Americas. The Irrigation Management System (IManSys) model was used to calculate optimum IRR for the baseline period (1986–2005) and two future periods (2055s and 2090s) subject to combination of five and seven temperature and precipitation levels, respectively. Predicted IRR show significant spatio-temporal variations across study regions. Future annual IRR are predicted to globally decrease; however, future monthly IRR showed mixed results. Future evapotranspiration and IRR are projected to decrease by up to 12 and 37%, respectively, in response to increases in CO2 concentration. Future citrus canopy interception and drainage below citrus rootzones are expected to slightly increase. Annual rainfall changes are negatively correlated with changes in IRR. These projections should help the citrus industry better understand potential climate change impacts on citrus IRR and major components of the water budget. Further studies are needed to investigate how these potential changes in CO2 concentration, temperature, evapotranspiration, rainfall, and IRR will affect citrus yield and its economic impact on the citrus industry
Some Pre-filters in EQ-Algebras
Get PDFIn this paper, the notion of an obstinate prefilter (filter) in an EQ-algebra ξ is introduced and a characterization of it is obtained by some theorems. Then the notion of maximal prefilter is defined and is characterized under some conditions. Finally, the relations among obstinate, prime, maximal, implicative and positive implicative prefilters are studied
An M/G/1 Retrial Queue with Single Working Vacation
Get PDFWe consider an M=G=1 retrial queue with general retrial times and single working vacation. During the working vacation period, customers can be served at a lower rate. Both service times in a vacation period and in a service period are generally distributed random variables. Using supplementary variable method we obtain the probability generating function for the number of customers and the average number of customers in the orbit. Furthermore, we carry out the waiting time distribution and some special cases of interest are discussed. Finally, some numerical results are presented
Inverse Problem for a Parabolic System
Get PDFIn this paper a numerical approach combining the least squares method and a genetic algorithm is proposed for the determination of the source term in an inverse parabolic system (IPS). A numerical experiment confirm the utility of this algorithm as the results are in good agreement with the exact data. Results show that a reasonable estimation can be obtained by the genetic algorithm within a CPU with clock speed 2.7 GHz
Exponential Chain Dual to Ratio cum Dual to Product Estimator for Finite Population Mean in Double Sampling Scheme
Get PDFThis paper considers an exponential chain dual to ratio cum dual to product estimator for estimating finite population mean using two auxiliary variables in double sampling scheme when the information on another additional auxiliary variable is available along with the main auxiliary variable. The expressions for bias and mean square error of the asymptotically optimum estimator are identified in two different cases. The optimum value of the first phase and second phase sample size has been obtained for the fixed cost of survey. To illustrate the results, theoretical and empirical studies have also been carried out to judge the merits of the suggested estimator with respect to strategies which utilized the information on two auxiliary variables
Finite Difference Schemes for Variable Order Time-Fractional First Initial Boundary Value Problems
Get PDFThe aim of the study is to obtain the numerical solution of first initial boundary value problem (IBVP) for semi-linear variable order fractional diffusion equation by using different finite difference schemes. We developed the three finite difference schemes namely explicit difference scheme, implicit difference scheme and Crank-Nicolson difference scheme, respectively for variable order type semi-linear diffusion equation. For this scheme the stability as well as convergence are studied via Fourier method. At the end, solution of some numerical examples are discussed and represented graphically using Matlab
Damping in microscale modified couple stress thermoelastic circular Kirchhoff plate resonators
Get PDFThe vibrations of circular plate in modified couple stress thermoelastic medium using Kirchhoff- Love plate theory has been presented. The basic equations of motion and heat conduction equation for Lord Shulman (L-S, 1967) theory are written with the help of Kirchhoff-Love plate theory. The thermoelastic damping of micro beam resonators is studied by applying normal mode analysis method. The solutions for the free vibrations of plates under clamped, simply supported and free boundary conditions are obtained. The analytical expressions for thermoelastic damping of vibration and frequency shift are obtained for generalized couple stress thermoelastic and coupled thermoelastic plates. Numerical results with the help of MATLAB programming software in case of silicon material has been presented. A computer algorithm has been constructed to obtain the numerical results. The thermoelastic damping and frequency shift with varying values of length and thickness for clamped, simply supported and free boundary conditions in the absence and presence of couple stress are presented graphically. Comparisons are made with different modes of vibrations and also with and without couple stress parameter. Some special cases are obtained in the present problem. The thermoelastic damping have many applications in (sensors) resonators in detecting Infrared (IR) and imaging in addition to chemical and biological agent sensing and their temperature dependence in design/construction of precision thermometers and communications
Effective Modified Hybrid Conjugate Gradient Method for Large-Scale Symmetric Nonlinear Equations
Get PDFIn this paper, we proposed hybrid conjugate gradient method using the convex combination of FR and PRP conjugate gradient methods for solving Large-scale symmetric nonlinear equations via Andrei approach with nonmonotone line search. Logical formula for obtaining the convex parameter using Newton and our proposed directions was also proposed. Under appropriate conditions global convergence was established. Reported numerical results show that the proposed method is very promising
Does the USA have market power in importing ethanol from Brazil?
No full textWith the ever increasing requirement in the USA to blend higher volumes of advanced biofuels with gasoline and the shortfall in domestic production to fulfil this requirement, imports of ethanol from Brazil will likely take on an even more vital role. In this paper, we examine US buyer power over Brazil. For methodology, we estimate the sugarcane ethanol residual supply function facing the USA. We find that while the USA had buyer power before the enactment of the advanced biofuels mandate, that buyer power disappeared after the mandate. One possible explanation is that, given that Brazil is the primary source of the sugarcane ethanol, the mandate requirement has increased rivalry between the USA and the remaining importers, creating a perfect market overlap between the rivals