40 research outputs found

    Microwave-assisted Fischer Indole Synthesis of 1,2,3,4-tetrahydrocarbazole using Pyridinium-based Ionic Liquids

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    AbstractMicrowave-assisted organic synthesis using ionic liquids is believed to enhance efficiency of the reaction leading to a cleaner method, higher product yields and shorter reaction times. Six pyridinium-based ionic liquids were prepared from 2-methylpyridine and a series of alkyl bromides (R: n-C4, sec-C4, t-C4, C6, C8 and Bn) by oil bath heating at 80, 90, 100 and 110°C. The ionic liquids product yield efficiency has direct relationship with heating temperatures affording highest yields at 110°C of 71.15%, 8.20%, 45.96%, 57.75%, 48.02% and 80.45% for each respective alkyl bromides. The catalytic activities of the synthesized ionic liquids in the Fischer indole synthesis of THC were examined. The highest yield of 67.82% is found to be less satisfactory compared to the use of the Lewis acid standard, ZnCl2, which gave 79.89%. On the other hand, the use of the pyridinium-based ionic liquids in conjunction with ZnCl2 afforded better yields than individual test catalysts resulting to 89.66% of the THC. Structural effects such as branching and chain length of the alkyl bromides for the synthesis of ionic liquids and the THC have negative effects on the product yields

    Assessing the benefits of international portfolio diversification in bonds and stocks.

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    This paper considers a stylized asset pricing model where the returns from exchange rates, stocks and bonds are linked by basic risk-arbitrage relationships. Employing GMM estimation and monthly data for 18 economies and the US (treated as the domestic country), we identify through a simple test the countries whose assets strongly comove with US assets and the countries whose assets might other larger diversification benefits. We also show that the strengthening of the comovement of returns across countries is neither a gradual process nor a global phenomenon, reinforcing the case for international diversification. However, our results suggest that fund managers are better other constructing portfolios selecting assets from a subset of countries than relying on either fully inter-nationally diversified or purely domestic portfolios. JEL Classification: F31, G10asset pricing, Exchange Rates, international parity conditions, market integration, stochastic discount factor

    Assessing the benefits of international portfolio diversification in bonds and stocks.

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    This paper considers a stylized asset pricing model where the returns from exchange rates, stocks and bonds are linked by basic risk-arbitrage relationships. Employing GMM estimation and monthly data for 18 economies and the US (treated as the domestic country), we identify through a simple test the countries whose assets strongly comove with US assets and the countries whose assets might other larger diversification benefits. We also show that the strengthening of the comovement of returns across countries is neither a gradual process nor a global phenomenon, reinforcing the case for international diversification. However, our results suggest that fund managers are better other constructing portfolios selecting assets from a subset of countries than relying on either fully inter-nationally diversified or purely domestic portfolios

    To surcharge or not to surcharge? A two-sided market perspective of the no-surchage rule

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    In Electronic Payment Networks (EPNs) the No-Surcharge Rule (NSR) requires that merchants charge the same final good price regardless of the means of payment chosen by the customer. In this paper, we analyze a three-party model (consumers, merchants, and proprietary EPNs) to assess the impact of a NSR on the electronic payments system, in particular, on competition among EPNs, network pricing to merchants and consumers, EPNs' profits, and social welfare. We show that imposing a NSR has a number of effects. First, it softens competition among EPNs and rebalances the fee structure in favor of cardholders and to the detriment of merchants. Second, we show that the NSR is a profitable strategy for EPNs if and only if the network e¤ect from merchants to cardholders is sufficiently weak. Third, the NSR is socially (un)desirable if the network externalities from merchants to cardholders are sufficiently weak (strong) and the merchants' market power in the goods market is sufficiently high (low). Our policy advice is that regulators should decide on whether the NSR is appropriate on a market-by-market basis instead of imposing a uniform regulation for all markets. JEL Classification: L13, L42, L80American Express, Discover, Electronic payment system, market power, MasterCard, network externalities, no-surcharge rule, regulation, two-sided markets, Visa

    Docking and Molecular Dynamics Simulation of Carbonic Anhydrase II Inhibitors from Phenolic and Flavonoid Group

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    AbstractCarbonic Anhydrase II (CAII) has role in pH regulation, water transport and hydration of CO2. In addition, CAII is also related to many diseases, including glaucoma, tumours, epilepsy, diabetes and osteopetrosis. Various inhibitors for CAII have been developed and commercialized as a drug. Recent development of CAII inhibitors drive the invention of novel inhibitors based on natural product structures and their derivatives. This research aim to screen potential inhibitors from phenolic and flavonoid groups by in silico approach. The screening of natural products compounds was performed by a molecular docking method. The best ligand derived from the molecular docking selection was further refined with a molecular dynamics simulation and the resulted structure was used to evaluate the stability of CAII-ligand complex. By using the upper mentioned procedures, fisetin (Fic) and 6-(3,4-dihydroxyphenyl)-5,6,7,8-tetrahydronaphthalene-1,3,7-triol (Afr3) were strongly suggested to be a potent inhibitor for CAII

    On the Shoulders of Giants: Reflections on the Foundations and Futures of the Study of Gambling

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    Dr. Bo Bernhard was invested as the Phillip G. Satre Chair in Gaming Studies and delivered the Robert D. Faiss guest lecture on gaming law policy on April 5, 2018

    Identification of new Keynesian Phillips Curves from a global perspective.

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    New Keynesian Phillips Curves (NKPC) have been exten-sively used in the analysis of monetary policy, but yet there are a number of issues of concern about how they are estimated and then related to the underlying macro-economic theory. The first is whether such equations are identified. To check identification requires specifying the process for the forcing variables (typically the output gap) and solving the model for inflation in terms of the observables. In practice, the equation is estimated by GMM, relying on statistical criteria to choose instruments. This may result in failure of identification or weak instruments. Secondly, the NKPC is usually derived as a part of a DSGE model, solved by log-linearising around a steady state and the variables are then measured in terms of deviations from the steady state. In practice the steady states, e.g. for output, are usually estimated by some statistical procedure such as the Hodrick-Prescott (HP) filter that might not be appropriate. Thirdly, there are arguments that other variables, e.g. interest rates, foreign inflation and foreign output gaps should enter the Phillips curve. This paper examines these three issues and argues that all three benefit from a global perspective. The global per-spective provides additional instruments to alleviate the weak instrument problem, yields a theoretically consistent measure of the steady state and provides a natural route for foreign inflation or output gap to enter the NKPC

    Fixed and variable-rate mortgages, business cycles and monetary policy

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    The aim of this paper is twofold. First, I study how the proportion of fixed and variable-rate mortgages in an economy can affect the way shocks are propagated. Second, I analyze optimal implementable simple monetary policy rules and the welfare implications of this proportion. I develop and solve a New Keynesian dynamic stochastic general equilibrium model that features a housing market and a group of constrained individuals who need housing collateral to obtain loans. A given proportion of constrained households borrows at a variable rate, while the rest borrows at a fixed rate. The model predicts that in an economy with mostly variable-rate mortgages, an exogenous interest rate shock has larger effects on borrowers than in a fixed-rate economy. Aggregate effects are also larger for the variable-rate economy. For plausible parametrizations, differences are muted by wealth effects on labor supply and by the presence of savers. More persistent shocks, such as inflation target and technology shocks, cause larger aggregate differences. From a normative perspective I find that, in the presence of collateral constraints, the optimal Taylor rule is less aggressive against inflation than in the standard sticky-price model. Furthermore, for given monetary policy, a high proportion of fixed-rate mortgages is welfare enhancin

    Human and Professional Sustainable Development by Using the EFI ROM Creative Method

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    AbstractElaborated for the human and professional sustainable development of human resources within innovative enterprises by using creative techniques for rendering efficient own activities. A solution for promoting innovative management in the field of human resources in these units is the use of the own original creative method EFI-ROM. It can be applied to selfmanagement and all management hierarchical levels with responsibilities in short, medium and long-term decision. It was tested on the occasion of carrying out some innovative project. In the present paper we present an improved variant and adjusted to the specifics of innovative organizations

    Distributional Patterns of Pseudacteon Associated with the Solenopsis saevissima Complex in South America

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    Classical biological control efforts against imported fire ants have largely involved the use of Pseudacteon parasitoids. To facilitate further exploration for species and population biotypes a database of collection records for Pseudacteon species was organized, including those from the literature and other sources. These data were then used to map the geographical ranges of species associated with the imported fire ants in their native range in South America. In addition, we found geographical range metrics for all species in the genus and related these metrics to latitude and host use. Approximately equal numbers of Pseudacteon species were found in temperate and tropical regions, though the majority of taxa found only in temperate areas were found in the Northern Hemisphere. No significant differences in sizes of geographical ranges were found between Pseudacteon associated with the different host complexes of fire ants despite the much larger and systemic collection effort associated with the S. saevissima host group. The geographical range of the flies was loosely associated with both the number of hosts and the geographical range of their hosts. Pseudacteon with the most extensive ranges had either multiple hosts or hosts with broad distributions. Mean species richnesses of Pseudacteon in locality species assemblages associated with S. saevissima complex ants was 2.8 species, but intensively sampled locations were usually much higher. Possible factors are discussed related to variation in the size of geographical range, and areas in southern South America are outlined that are likely to have been under-explored for Pseudacteon associated with imported fire ants
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