Essays on Trade Costs, Supply Chain Uncertainty and CEO Compensation

This dissertation consists of two chapters that examine high managerial pay and supply chain uncertainty. Chapter 1 constructs a game-theoretic model in which high CEO pay emerges as the outcome of an arms race, with each firm paying its CEO highly to protect its competitive position against rivals who also pay highly. For an arms race to emerge, highly-paid CEOs must generate idiosyncratic, privately-known internal effects on profit, and CEO pay disparities must also generate asymmetric profit differences from external effects beyond the simple differences in pay. If the distribution of internal effects satisfies a key uniformity condition, an arms race emerges as the only equilibrium of the game. Chapter 2 examines the impact of supply chain uncertainty and ordering costs on trade. Importers hold safety stock to hedge against delays in delivery. An increase in supply chain uncertainty raises safety stocks, increases inventory costs, and reduces imports from locations with high delivery time uncertainty. An increase in order costs reduces a firm\u27s shipping frequency and increases average inventory holding cost for the firm\u27s base inventory stock. As a result, firms import less from locations with high ordering costs to reduce average inventory holding costs. Detailed data on actual and expected arrival times of vessels at U.S. ports serve to measure supply chain uncertainty consistent with the theory. Combined with detailed data on U.S. imports, freight charges and unit values, a 10 percent increase in supply-chain uncertainty lowers imports by as much as 3.7 percent. This is evidence that delivery uncertainty imposes a cost on imports according to the management of safety stocks. A one percent increase in ordering costs lowers imports by as much as 1.2 percent. Ordering costs impact the intensive margin of trade due to the management of base inventory stocks

An educational technology for developing professionally-oriented EFL communicative competence: its acmeological potential

AbstractThis paper addresses the problem of creating effective educational technologies aimed at developing university students’ professionally-oriented EFL communicative competence in research-oriented higher educational settings. Two techniques (mini-research and individual educational trajectory), being actional components of the educational technology developed, were analyzed from the acmeological potential perspective based on the study undertaken. The study participants were undergraduates and master's students majoring in non-language-related fields

Luminescence and vacuum ultraviolet excitation spectroscopy of cerium doped Gd3Ga3Al2O12 single crystalline scintillators under synchrotron radiation excitations

Authors gratefully acknowledge the financial support from the Latvian Science Council grant LZP-2018/2-0358 . The research leading to this result has been supported by the project CALIPSO plus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON2020 . The work of A.P.K. was supported by the Ministry of Science and Higher Education of the Russian Federation , state contracts No. 11.6181.2017/ITR .Cerium doped Gd3Ga3Al2O12 (GGAG) single crystals as well as GGAG:Ce single crystals co-doped by divalent (Mg2+, Ca2+), trivalent (Sc3+) or tetravalent (Zr4+, Ti4+) ions have been studied by means of the excitation luminescence spectroscopy in vacuum ultraviolet spectral range. Synchrotron radiation from the undulator beam was utilized for the luminescence excitation in the energy range from 4.5 to 800 eV. The influence of the co-dopant ions on the excitonic transitions as well as on the intrinsic defects in GGAG was revealed examining the luminescence emission and excitation spectra of both Gd3+ and Ce3+ ions in all single crystals studied. Special attention was paid to the analysis of Ce3+ excitation spectra in VUV spectral range (4.5–45 eV) where multiplication of electronic excitation (MEE) processes occur. It was obtained that GGAG:Ce single crystals having different co-dopant ions reveal distinguished efficiency of MEE. The role of intrinsic defects in MEE processes in the co-doped GGAG:Ce single crystals was elucidated.Latvian Science Council LZP-2018/2-0358,730872; Ministry of Science and Higher Education of the Russian Federation 11.6181.2017/ITR; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²https://www.sciencedirect.com/science/article/pii/S2211379719334527?via%3Dihu

Do ternary liquid mixtures exhibit negative main Fick diffusion coefficients?

Experimental data on Fick diffusion coefficients of ternary and higher mixtures depend on the reference frame; those which are in common use are associated with the average velocity either with respect to volume, mass or mole number. In this study, the dependence of diffusion coefficients on the reference frame is thoroughly analyzed for three ternary mixtures of different types. The first one, tetralin–isobutylbenzene–dodecane, can almost be considered as ideal, the second one, cyclohexane–toluene–methanol, exhibits liquid–liquid phase separation and the third one, water–ethanol–triethylene glycol, contains three associating species and is also strongly non-ideal. Experimental diffusion coefficient data sampled in the volume reference frame are transformed to the molar and mass reference frames. The required partial molar volumes are derived from present density measurements. Four additional mixtures are considered along a single or two composition paths. A highlight of this study is the existence of a strong similarity of the main diffusion coefficients in the volume and mass reference frames for all considered mixtures. When the excess volume is small, the coefficients in the molar reference frame are also similar. However, for the mixture with a large excess volume (containing water), the diffusion coefficients in the molar reference frame differ significantly, even indicating negative main diffusion coefficients. It is shown that negative main diffusion coefficients appear due to relatively large experimental uncertainties of cross diffusion coefficients, which are propagated and amplified by frame transformation

Optical characteristics of single crystal Gd3Al2Ga3O12 : Ce

New emerging high-energy radiation detection techniques are based on the use of rare-earth ion doped materials. There is a great demand for new inorganic scintillators for medical applications, including X-ray and g radiation detection. In these applications, the new scintillating materials must comply with the main requirements such as high optical quality, high light yield, short response time etc. Materials satisfying these requirements include Gd3Al2Ga3O12 : Ce (GAGG : Ce) scintillating single crystals. By now the optical characteristics of GAGG : Ce have been studied insufficiently. We have therefore measured the spectral reflectance and transmittance characteristics of these crystals using optical spectroscopy in the 200–750 nm range. We have also measured the absorbance and refractive indices and the extinction coefficients, and assessed the optical band gap for GAGG : Ce crystals. For measuring the refractive indices, we have used two spectrophotometric methods, i.e. by the measured Brewster angle and by the reflectance for low incidence angles, i.e., close to the normal. Based on the results we have drawn up the dispersion functions of the refractive indices

Mathematical modeling of physical and chemical processes in porous media in solving the problems of nanocomposite materials and water-filling

ABSTRACT: Introduction. The complexity and laboriousness of system studies of physical and chemical processes in the volume and at the interface of the porous medium determines the need to apply mathematical modeling. This allows not only to identify and study the determining physical and chemical processes in a porous medium, but also to solve the problems of optimization and optimal control of processes and regimes by selecting the most favorable conditions. Methods and Materials. The method of mathematical modeling is used to study the processes, including the creation of composite and nanocomposite materials, as well as the moistening and moisture absorption in porous materials. In this context, the porous material is treated as a pseudohomogeneous medium with averaged physical and technological parameters. Results. The mathematical models of physical and chemical processes in the porous medium have been developed, the boundary conditions have been formulated, physical and effective constants have been determined. The processes in porous medium during metallization of carbon-graphite fibrous material, moistening of compacted textile material by an air flow, and moisture absorption by porous construction materials have been studied. Discussion. The adequacy of mathematical models to real physical and chemical processes is discussed. The results of calculations obtained by modeling equations implemented in the form of computer computational algorithms and experiments are compared. Conclusions. The effectiveness of the method for studying physical-chemical processes in a porous medium and for calculating optimal values of technological parameters has been established

Effect of Ca2+ and Zr4+ co-doping on the optical properties of Gd3Al2Ga3O12: Ce single crystals

Scintillation materials capable of transforming absorbed high-energy particles into visible radiation photons find multiple applications including advanced medical visualization methods. Gd3Al2Ga3O12 : Ce is a promising oxygen-containing sсintillator for fabrication of detecting crystals of positron emission tomographs due to its unique properties, e.g. high density, high light yield, radiation hardness etc. However its kinetic parameters currently restrict its use in this field. Attempts at improving the luminescence rise and decay time kinetics by introducing additional impurities have become a top priority task for many researchers. Analyzing literary data one can conclude that the optical parameters of co-doped crystals have been studied insufficiently or have not been studied at all. We have studied Ca2+ and Zr4+ co-doped Gd3Al2Ga3O12 : Ce single crystals by optical spectroscopy in the 200–2200 nm. We have taken the optical transmittance, absorption and reflection spectra and measured the refractive indices. Dispersion curves have been obtained by approximation of experimental refractive indices using the Brewster method and the Cauchy equation. Material constants of these equations have been estimated for each of the co-doped crystals

Influence of Aerobic bioprocessing on Composition and Sorption Properties of Berezovsky Brown Coal

Изучено влияние аэробного воздействия штаммов бактерий Pseudomonas aeroginosa LMG 1242, Pseudomonas moorei и Delftia tsuruhatensis на состав и сорбционные свойства бурого угля Березовского месторождения. Проведено сравнение свойств продуктов аэробной биопереработки бурого угля указанными штаммами бактерий и штаммом Acinetobacter calcoaceticus ВКПМ В-4833. Показано, что для сорбции ионов хрома из водных растворов наиболее эффективны продукты, полученные в результате биомодификации бурого угля штаммами бактерий Pseudomonas moorei и Delftia tsuruhatensisThe influence of the aerobic impact by strains of bacteria Pseudomonas aeroginosa LMG 1242, Pseudomonas moorei and Delftia tsuruhatensis on the structure and the sorption properties of Berezovsky brown coal was studied. The properties of products of aerobic impact by these strains of bacteria and Acinetobacter calcoaceticus PMBC In-4833 were compared. It was shown that products of the aerobic impact by strains of bacteria Pseudomonas moorei and Delftia tsuruhatensis on brown coal are the most effective in the sorption of chromium from aqueous solution

Influence of the Sc cation substituent on the structural properties and energy transfer processes in GAGG:Ce crystals

The influence of the Sc cation substituent on the structural and luminescence properties of GAGG:Ce crystals was studied. Unit cell parameters and space groups were obtained using XRD analysis. The chemical compositions of the crystals were determined using SEM-EDX and TEM-EDX techniques. Structures were refined by the Rietveld method and the distribution of Al/Ga/Sc cations between octahedral and tetrahedral sites was obtained. The influence of Sc on the electronic band structure and the energy of the 4f and 5d Ce3+ levels is shown. The modification of the band structure induced by the Sc electronic states results in the suppression of Gd emission and enhancement of Ce3+ emission at low temperatures. The Ce3+ emission decay is accelerated under high-energy excitation of the Sc-containing GAGG compound