5,624 research outputs found
Recommended from our members
Opaque Selling
We study “opaque” selling in multiproduct environments – a marketing practice in which sellers strategically withhold product information by keeping important characteristics of their products hidden until after purchase. We show that a monopolist will always use opaque selling, but it is not first-best optimal to do so. However, opaque selling might be used at the constrained optimum (with the monopolist’s pricing behavior taken as given). For linear disutility costs, it is optimal for a monopolist to offer a single opaque product
Recommended from our members
Product line design
We characterize the product line choice and pricing of a monopolist from the upper envelope of net marginal revenue curves to the individual product demand functions. The equilibrium product line constitutes those varieties yielding the highest upper envelope. In a generalized vertical differentiation framework, the equilibrium line is exactly the same as the first-best socially optimal line. These upper envelope and first-best optimal line findings extend to symmetric Cournot oligopoly
Smoothness of the Green Function for a Special Domain
Cataloged from PDF version of article.We consider a compact set K ⊂ ℝ in the form of the union of a sequence of segments. By means of nearly Chebyshev polynomials for K, the modulus of continuity of the Green functions gℂ\K is estimated. Markov's constants of the corresponding set are evaluated. © Instytut Matematyczny PAN, 2012
Impact differences among the landing phases of a drop vertical jump in soccer players
The aim of this study was to examine the differences of landing phase biomechanics between the players who had anterior cruciate ligament (ACL) reconstruction and healthy participants during single leg drop vertical jump. In this study, 11 soccer players who had anterior cruciate ligament reconstruction (aged 23.0±3.6 years, height 177±5.0 cm, weight 83.8±11.7 kg) and 9 healthy soccer players( aged 22.2±2.4 years, height 178±3.0 cm, weight 74.3±6.1 kg) participated voluntarily. During the data collection phase three high speed cameras synchronized to each other and force plate were used. Visual analysis programme and MATLAB were used to calculate kinetic and kinematic variables. Landing techniques of the subjects' were examined by flexion angle of knee, ground reaction force and moment parameters. The statistical analyses of the measured results were performed by t-test and Pearson Correlation analysis. According to the results, it was determined that peak vertical ground reaction force exhibited significant phase differences (p=0.00, and p=0.00, respectively) between the groups. Obtained results can be explained with "quadriceps avoidance" motion pattern which is characterized by decreased quadriceps activity and lower external knee flexion moment in an effort to control anterior translation of the tibia in subjects with ACL reconstruction. A better understanding of the different phases during single-leg landings can shed a light on mechanism of non-contact anterior crucaite ligament injuries therefore future researches should assess how phase differences affect drop vertical jump performance. © 2018 Montenegrin Sports Academy. All rights reserved
Determination of the accumulator plants in Kucukcekmece Lake (Istanbul)
Soils are polluted by actions like using commercial fertilizers, pesticides, soil regulators and hormones to increase the amount and quality of agricultural production, discharge of soil and liquid wastes, performing wastewater sludge applications, using polluted waters in agricultural irrigation, atmospheric precipitations and radioactive sprays. It is an important environmental problem to reform and clean the soils polluted with heavy metals. Phytoremediation is a measure which uses several plants to remove the pollutants from water and soil to reduce, completely extract, control or immobilize them. The plants used for this reason are referred to as the accumulators. Metal accumulation can occur in several different families like small annual grass to perennial bushes and trees. For remediation or cleaning of the soils polluted with heavy metals, the ideal plant species are the ones which can produce high amounts of biomass, and can accumulate and tolerate the pollutants. In this study, the Cd and Zn contents obtained from Kucukcekmece Lake border were monitored on monthly basis and it was aimed at determining the plant species with accumulation ability. The plants chosen for this activity were Labiatae galatica, Compositae cardueae, Cypereace carex, and Phragmites australis. Compositae cardueae was the most efficient species in terms of mean heavy metal intake performance.Key words: Heavy metals, accumulators, phytoremediation, soil pollution, Cd, Zn
Modeling the Influence of Antifreeze Proteins on Three-Dimensional Ice Crystal Melt Shapes using a Geometric Approach
The melting of pure axisymmetric ice crystals has been described previously
by us within the framework of so-called geometric crystal growth.
Nonequilibrium ice crystal shapes evolving in the presence of hyperactive
antifreeze proteins (hypAFPs) are experimentally observed to assume ellipsoidal
geometries ("lemon" or "rice" shapes). To analyze such shapes we harness the
underlying symmetry of hexagonal ice Ih and extend two-dimensional geometric
models to three-dimensions to reproduce the experimental dissolution process.
The geometrical model developed will be useful as a quantitative test of the
mechanisms of interaction between hypAFPs and ice.Comment: 15 pages, 5 figures; Proc. R. Soc. A, Published online before print
June 27, 201
Interactions mechanism of commonly used drugs for the treatment of Covid-19
In this study conformation analysis of seven drugs commonly used in the treatment of COVID-19 was performed. The most stable conformers of the drug molecules were used as initial data for docking analysis. Using the Cavityplus program, the probable most active binding sites of both apo and holo forms of COVID-19 main protease enzyme (Mpro) and spike glycoprotein of SARSCoV-2 receptors were determined. The interaction mechanisms of the 7 FDA approved drugs (arbidol, colchicine, dexamethasone, favipiravir, galidesivir, hydroxychloroquine, remdesivir) were examined using the AutoDock Vina program. The six of the seven drugs were found to be more stable in binding to apo form of COVID-19 Mpro and spike glycoprotein. Moreover, a set of molecular mechanics (MM) Poisson-Boltzmann (PB) surface area (SA) calculations on the investigated drugs-protein systems were performed and the estimated binding free energy of remdesivir and the apo form of Mpro system was found to be the best. The interaction results of FDA drugs with the apo form of COVID-19 Mpro and spike glycoprotein can play an important role for the treatment of COVID-19.
KEY WORDS: COVID-19, Drugs, Molecular modelling, Conformational analysis, Molecular docking
Bull. Chem. Soc. Ethiop. 2020, 34(3), 613-623.
DOI: https://dx.doi.org/10.4314/bcse.v34i3.1
Determination of the LO phonon energy by using electronic and optical methods in AIGaN/GaN
Cataloged from PDF version of article.The longitudinal optical (LO) phonon energy in AlGaN/GaN heterostructures is determined from temperature-dependent Hall effect measurements and also from Infrared (IR) spectroscopy and Raman spectroscopy. The Hall effect measurements on AlGaN/GaN heterostructures grown by MOCVD have been carried out as a function of temperature in the range 1.8-275 K at a fixed magnetic field. The IR and Raman spectroscopy measurements have been carried out at room temperature. The experimental data for the temperature dependence of the Hall mobility were compared with the calculated electron mobility. In the calculations of electron mobility, polar optical phonon scattering, ionized impurity scattering, background impurity scattering, interface roughness, piezoelectric scattering, acoustic phonon scattering and dislocation scattering were taken into account at all temperatures. The result is that at low temperatures interface roughness scattering is the dominant scattering mechanism and at high temperatures polar optical phonon scattering is dominant
Influence functions of trimmed likelihood estimators for lifetime experiments
We provide a general approach for deriving the influence function for trimmed likelihood estimators using the implicit function theorem. The approach is applied to lifetime models with exponential or lognormal distributions possessing a linear or nonlinear link function. A side result is that the functional form of the trimmed estimator for location and linear regression used by Bednarski and Clarke (1993, 2002) and Bednarski et al. (2010) is not generally always the correct functional form of a trimmed likelihood estimator. However, it is a version for which the influence function has a treatable form. A real data example shows the effect of trimming using a nonlinear link function for either the exponential or lognormal distribution
Influence functions of trimmed likelihood estimators for lifetime experiments
We provide a general approach for deriving the influence function for trimmed likelihood estimators using the implicit function theorem. The approach is applied to lifetime models with exponential or lognormal distributions possessing a linear or nonlinear link function. A side result is that the functional form of the trimmed estimator for location and linear regression used by Bednarski and Clarke (1993, 2002) and Bednarski et al. (2010) is not generally always the correct functional form of a trimmed likelihood estimator. However, it is a version for which the influence function has a treatable form. A real data example shows the effect of trimming using a nonlinear link function for either the exponential or lognormal distribution
- …