408 research outputs found

    Tax Incentives for Industry Synergy in Nigeria: A Pragmatic Proprietary System Advocacy

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    Tax incentives are quintessential fiscal provisions designed by core industry-driven governmental authorities to attract and empower investors in strategic sectors of the economy. In Nigeria, several booster reliefs are obtainable, but many industrialists show soft spot for investment tax credit (ITC) and re-investment allowance (RIA). This study, thus, examined the potency of these specifications in redefining corporate financial performance, particularly in terms of return on equity (ROE). Using financial (secondary) data obtained from a net sample of 58 firms quoted on the Nigerian Stock Exchange (NSE); the correlation, regression and Z-test analytical results were vividly in the affirmative. Leveraging on the outcomes, therefore, a Tax Incentive – Corporate Profitability Impact Model (TICPIM) is conceptualized and presented herein, to accord meaningful impetus to a pragmatic proprietary system advocacy (PPSA), which is expedient for the Nigerian economy. It is expected that these tax appeals and ideals would conscientiously grow critical industries in nation to greater productive and competitive heights.Keywords: Industrial investment, Nigerian economy, Tax incentive

    Polarization Maintaining, Very-Large-Mode Area, Er Fiber Amplifier for High Energy Pulses at 1572.3 nm

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    We demonstrate the first polarization maintaining, very-large-mode-area Er-doped fiber amplifier with ~1000 square micron effective area. The amplifier is core pumped by a Raman fiber laser and is used to generate single frequency one microsecond pulses with pulse energy of 368 microJoules, M2 of 1.1, and polarization extinction greater than 20 dB. The amplifier operates at 1572.3 nm, a wavelength useful for trace atmospheric CO2 detection

    Photonic Microresonators Created by Slow Optical Cooking

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    Silica and water are known as exceptionally inert chemical materials whose interaction is not completely understood. Here we show that the effect of this interaction can be significantly enhanced by optical whispering gallery modes (WGMs) propagating in a silica microcapillary filled with water. Our experiments demonstrate that WGMs, which evanescently heat liquid water over several hours, induce permanent alterations in silica material characterized by the subnanometer variation of the WGM spectrum. We use the discovered effect to fabricate optical WGM microresonators having potential applications in optical signal processing and microfluidic sensing. Our results pave the way for the ultraprecise fabrication of resonant optical microdevices and the ultra-accurate characterization of physical and chemical processes at solid-liquid interfaces

    A dedicated electric oven for characterization of thermoresistive polymer nanocomposites

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    AbstractThe construction, characterization and control of an electric oven dedicated to the study of thermoresistive polymer nanocomposites is presented. The oven is designed with a heating plate capable of reaching 300°C with a resolution of 0.3°C and an area of uniform temperature of 3.8cm×2.5cm. The temperature is regulated by means of a discrete proportional–integral–derivative controller. A heat transfer model comprising three coupled non-linear differential equations is proposed to predict the thermal profiles of the oven during heating and cooling, which are experimentally verified. The oven is used for thermoresistive characterization of polymer nanocomposites manufactured from a polysulfone polymer and multiwall carbon nanotubes

    Benzopyrazine-Based Small Molecule Inhibitors As Trypanocidal and Leishmanicidal Agents: Green Synthesis, In Vitro, and In Silico Evaluations

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    World Health Organization (WHO) identified twenty tropical disease categories as neglected tropical diseases (NTDs)1. Chagas’ disease (also known as American trypanosomiasis) and leishmaniasis are two major classes of NTDs. The total number of mortality, morbidity, and disability attributed each year due to these two categories of diseases in magnitudes is much higher than the so-called elite diseases like cancer, diabetes, AIDS, cardiovascular and neurodegenerative diseases. Impoverished communities around the world are the major victim of NTDs. The development of new and novel drugs in the battle against Chagas’ disease and leishmaniasis is highly anticipated. An easy and straightforward on-water green access to synthesize benzopyrazines is reported. This ultrasound-assisted procedure does not require any catalyst/support/additive/hazardous solvents and maintains a high atom economy. A series of eleven benzopyrazines has been synthesized, and most of the synthesized compounds possess the drug-likeness following Lipinski’s “Rule of 5”. Benzopyrazines 3 and 4 demonstrated moderate leishmanicidal activity against L. mexicana (M378) strain. The selective lead compound 1 showed good leishmanicidal, and trypanocidal activities (in vitro) against both L. mexicana (M378) and T. cruzi (NINOA) strains compared to the standard controls. The in vitro trypanocidal and leishmanicidal activities of the lead compound 1 have been validated by molecular docking studies against four biomolecular drug targets viz. T. cruzi histidyl-tRNA synthetase, T. cruzi trans-sialidase, leishmanial rRNA A-site, and leishmania major N-myristoyl transferase

    Temporal and spatiotemporal autocorrelation of daily concentrations of Alnus, Betula, and Corylus pollen in Poland

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    The aim of the study was to determine the characteristics of temporal and space–time autocorrelation of pollen counts of Alnus, Betula, and Corylus in the air of eight cities in Poland. Daily average pollen concentrations were monitored over 8 years (2001–2005 and 2009–2011) using Hirst-designed volumetric spore traps. The spatial and temporal coherence of data was investigated using the autocorrelation and cross-correlation functions. The calculation and mathematical modelling of 61 correlograms were performed for up to 25 days back. The study revealed an association between temporal variations in Alnus, Betula, and Corylus pollen counts in Poland and three main groups of factors such as: (1) air mass exchange after the passage of a single weather front (30–40 % of pollen count variation); (2) long-lasting factors (50–60 %); and (3) random factors, including diurnal variations and measurements errors (10 %). These results can help to improve the quality of forecasting models

    Synthesis and in vitro antiprotozoal activity of some 2- amino-4-phenyloxazole derivatives

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    Purpose: To prepare some 2-amino-4-(p-substituted phenyl)-oxazole derivatives and to evaluate their in vitro antiprotozoal activity against Giardia lamblia and Trichomonas vaginalis.Methods: The 2-amino-4-(p-substituted phenyl)-oxazoles (a-g) were synthesized by microwave (MW) irradiation of mixtures of p-substituted 2-bromoacetophenones and urea in dimethylformamide (DMF). All compounds were identified by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and lowand high-resolution mass spectrometry (HRMS). NMR assignments were made based on heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) experiments. Each synthesized compound’s melting point was determined. Antiprotozoal activity against Giardia intestinalis and Trichomonas vaginalis was quantified using a rigorous and sensitive subculture method. The commercial drug, metronidazole, was used as positive control. The 50 % inhibitory concentration (IC50) of the antiprotozoal agents for each protozoa was determined.Results: Seven 2-amino-4-(p-substituted phenyl)-oxazoles (a-g) were synthesized. The most active compounds against G. lamblia was 2-amino-4-(p-benzoyloxyphenyl)-oxazole (3d) with an IC50 of 1.17 ÎŒM, while compound 3e (2-amino-4-(p-bromophenyl)-oxazole) showed the highest anti-trichomonal activity (IC50, 1.89 ÎŒM).Conclusion: The in vitro antigiardial activity of 2-amino-4-(p-benzoyloxyphenyl) oxazole was higher than that exhibited by metronidazole; however, it is necessary increase the number of synthetic derivatives in order to be able to determine their structure-activity relationship.Keywords: Antiprotozoal, 2-Amino-4-phenyl-oxazoles, Giardia lamblia, Trichomonas vaginali
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