Accuracy of simulations for stochastic dynamic models

This paper provides a general framework for the simulation of stochastic dynamic models. Our analysis rests upon a continuity property of invariant distributions and a generalized law of large numbers. We then establish that the simulated moments from numerical approximations converge to their exact values as the approximation errors of the computed solutions converge to zero. These asymptotic results are of further interest in the comparative study of dynamic solutions, model estimation, and derivation of error bounds for the simulated moments

ACCURACY OF SIMULATIONS FOR STOCHASTIC DYNAMIC MODELS

This paper provides a general framework for the simulation of stochastic dynamic models. Our analysis rests upon a continuity property of invariant distributions and a generalized law of large numbers. We then establish that the simulated moments from numerical approximations converge to their exact values as the approximation errors of the computed solutions converge to zero. These asymptotic results are of further interest in the comparative study of dynamic solutions, model estimation, and derivation of error bounds for the simulated moments.

Problems in the numerical simulation of models with heterogeneous agents and economic distortions

Our work has been concerned with the numerical simulation of dynamic economies with heterogeneous agents and economic distortions. Recent research has drawn attention to inherent difficulties in the computation of competitive equilibria for these economies: A continuous Markovian solution may fail to exist, and some commonly used numerical algorithms may not deliver accurate approximations. We consider a reliable algorithm set forth in Feng et al. (2009), and discuss problems related to the existence and computation of Markovian equilibria, as well as convergence and accuracy properties. We offer new insights into numerical simulation.Econometric models

Accuracy of simulations for stochastic dynamic models.

This paper provides a general framework for the simulation of stochastic dynamic models. Our analysis rests upon a continuity property of invariant distributions and a generalized law of large numbers. We then establish that the simulated moments from numerical approximations converge to their exact values as the approximation errors of the computed solutions converge to zero. These asymptotic results are of further interest in the comparative study of dynamic solutions, model estimation, and derivation of error bounds for the simulated moments.

Numerical simulation of nonoptimal dynamic equilibrium models

In this paper we present a recursive method for the computation of dynamic competitive equilibria in models with heterogeneous agents and market frictions. This method is based on a convergent operator over an expanded set of state variables. The fixed point of this operator defines the set of all Markovian equilibria. We study approximation properties of the operator as well as the convergence of the moments of simulated sample paths. We apply our numerical algorithm to two growth models, an overlapping generations economy with money, and an asset pricing model with financial frictions.Econometric models

Subgenual cingulate cortex activity in predicting risk factor and treatment response in depression

Major depressive disorder (MDD) contributes significantly to morbidity, disability, and decreased quality of life, despite the expansion of treatment options. This, in part, is caused by a lack of valid, applicable, and reliable biomarkers to predict the risk, treatment response, and prognosis of depression. In recent years, the anterior cingulate cortex, in particular pars subgenual (sgACC), has received much attention due to its potential utilization as a neural endophenotype for depression. This essay will discuss the functional activity of sgACC, mostly by functional magnetic resonance imaging, in relation to predicting risk for developing depression, predicting patient response-to-treatment, and eventually, to create a platform for personalized psychiatric approach to each patient. The caveats and conditions need to be met will also be discussed, in order to firmly establish sgACC activity as a valid biomarker for depression

Immobilization of glucose oxidase with polyurethane on carbon support

Glucose oxidase (GOD) has been immobilized by physical entrapment on polyurethane PU-6 matrix. It has been found that the enzyme acquires greater thermal stability on immobilization. Oxygen acts as a co-substrate for the redox reaction. However, maintaining oxygen concentration constant throughout the experiment is a difficult task. To overcome this we have coimmobilized ferrocene, which can act as an electron acceptor. 31P NMR results indicate that ferrocene is located in the close proximity of the active site of GOD. Moreover, simultaneous use of mediators such as ferricyanide, phenazine methosulphate or flavine mononucleotide have been found to facilitate electron transfer. Platinum, apart from being an expensive metal, is likely to exhibit adverse toxic effects during prolonged 'in-vivo' applications. Electrodes prepared using carbon in the place of platinum, show comparably good response. This opens a new possibility for making cheaper and biocompatible sensors

OPTIMIZATION OF SCREEN PRINTED REFERENCE ELECTRODE BASED ON CHARGE BALANCE AND POLY (BUTYL ACRYLATE) PHOTOCURABLE MEBRANE

This research focus on transforming the traditional design of reference electrode into all-solid-state reference electrode front-end using Ag/AgCl screen- printed electrodes. By replacing the internal reference solution of a traditional reference electrode by a solid photocurable membrane, an all-solid-state reference electrode can be achieved. The solid-state screen-printed reference electrode was designed using a photocurable acrylic film containing immobilized sodium tetrakis [3,5-bis(trifluoromethyl)phenyl] borate (NaTFPB) and trimethylocthylammonium chloride (TOMA-Cl). An optimum ratio of NaTFPB:TOMA-Cl = 1:1 produced a stable reference electrode. In the anions interference studies, all anions i.e. NO3-, Cl-, Br- and SO42- does not give effect to the SPRE except perchlorate anions. The all-solid-state reference electrodes was applied to the detection of potassium ions and ammonium ions. Validation of the all-screen-printed reference electrode was performed with reference electrode standard gel type. The validation results showed that all-solid-state screen-printed reference electrode demonstrated performance that was comparable to standard reference electrode

Synthesis and LB film formation of fatty acid- fad complex

Flavin adenine dinucleotide can exist in two oxidation states. Switching from one state to the other can be achieved chemically or electrically. The flavin undergoes reduction reversibly by two one electron steps or one two electron step, changing the chemistry of the enediamine subfunction of the isoalloxazine moiety. The adenine moiety is not involved in the catalysis, but helps in anchoring the coenzyme at the active site. The hydrophilicity of FAD has been changed by chemically attaching hydrocarbon chains to the noncatalytic adenine moiety. The modified coenzyme has been verified to retain the electro chemical, optical and the biochemical properties. The amphiphilic molecules can form monolayers at the air-water interface. A film of desired thickness can be formed on a solid support by means of monomolecular deposition using LB film technique. The characterization of the film has been done using spectrophotometric and electrochemical methods

OPTIMIZATION OF SCREEN PRINTED REFERENCE ELECTRODE BASED ON CHARGE BALANCE AND POLY (BUTYL ACRYLATE) PHOTOCURABLE MEBRANE

This research focus on transforming the traditional design of reference electrode into all-solid-state reference electrode front-end using Ag/AgCl screen- printed electrodes. By replacing the internal reference solution of a traditional reference electrode by a solid photocurable membrane, an all-solid-state reference electrode can be achieved. The solid-state screen-printed reference electrode was designed using a photocurable acrylic film containing immobilized sodium tetrakis [3,5-bis(trifluoromethyl)phenyl] borate (NaTFPB) and trimethylocthylammonium chloride (TOMA-Cl). An optimum ratio of NaTFPB:TOMA-Cl = 1:1 produced a stable reference electrode. In the anions interference studies, all anions i.e. NO3-, Cl-, Br- and SO42- does not give effect to the SPRE except perchlorate anions. The all-solid-state reference electrodes was applied to the detection of potassium ions  and ammonium ions. Validation of the all-screen-printed reference electrode was performed with reference electrode standard gel type. The validation results showed that all-solid-state screen-printed reference electrode demonstrated performance that was comparable to standard reference electrode.