Habits, Market Power, and Policy Selection

This paper examines monopolistic behavior in a framework with habit formation and consumer commitment. We show that time consistent output and pricing policies yield di®erent market outcomes. Policy selection determines the strategic properties of the producer's intra-personal game: current and future quantities are strategic com- plements, while current and future prices are strategic substitutes. In both a simple two-period model and an in¯nite-horizon model, we ¯nd that pricing policies allow the monopolist to attain higher equilibrium pro¯ts.Habit persistence, monopoly, time consistency

A THERMAL MODEL FOR WIRE ARC ADDITIVE MANUFACTURING

Layer-by-layer detailing processes, which used wire and electric arc - wire arc additive manufacturing (WAAM), are among the most productive in 3D metal printing technologies. From this point of view, the solution of the thermal task, and subsequently of the deformation problem, are particularly relevant. It is natural that these simulation modelling processes are closely related to welding, but at the same time it is necessary to take into account particularities that are crucial for WAAM and are not always relevant in welding. In this research, one such model is proposed, which takes into account the gradual filling of the working space with the deposited metal. The specific issues related to the construction of the model, the definition of the heat source and the first layer formation in the conditions of WAAM are considered. The obtained numerical results enable the prediction of the layer dimensions

Optimal Tax Rules for Addictive Consumption

This paper studies implementation of the social optimum in a model of habit formation. We consider taxes that address inefficiencies due to negative consumption externalities, imperfect competition, and self-control problems. Our contributions are to: i) account for producers’ market power; and ii) require implementation to be robust and time consistent. Together, these features can imply significantly lower taxes. We provide a general characterization of the optimal tax rule and illustrate it with two examples

Variations in semen quality parameters of Ovchepolian pramenka rams according to the method of collection and the meteorological season

The off-breeding season for rams is a time-limiting factor for their use in scientific aims. This research was set upon two aims: (1) to acknowledge the differences of semen quality collected throughout the year, and (2) to investigate which of the two commonly used methods for semen collection (artificial vagina - A.V. and electro ejaculation - E.E.) could prove to be more favorable in the off-breeding period. Five Ovchepolian Pramenka rams were used for this investigation. They were divided in two groups: group 1 (two rams), which was subjected to A.V. method, and group 2 (three rams), which was subjected to E.E. method for semen collection. Semen evaluation included: volume, spermatozoa concentration, live spermatozoa, ejaculate density and motility. According to the season, results have a high statistical significance for the volume (P<0.01) and motility (P<0.001) parameters. Group 1 and 2 results versification showed a high statistical significance for the motility score (P<0.001), ejaculate volume (P<0.01) and percentage of live spermatozoa (P<0.01) parameters. In conclusion, the A.V. method is more favorable for semen collection in late autumn, winter and spring time when rams are out of the breeding season

THE EFFECT OF EXTENDING RAM SPERM BEFORE AND AFTER CRYOPRESERVATION ON THEIR VIABILITY AND VELOCITY

The current study aimed to assess the effect of adding cryopreserving extender (soy-bean lecithin-SBLE), reduced glutathione (GSH), and seminal plasma (SP) before and after thawing on viability and velocity of cryopreserved ram sperm in liquid nitrogen. Fresh ejaculates (Ovchepolska pramenka rams, n=10) were collected and pooled. One portion was extended up to 50 million/ml with SBLE (control C-a), SBLE and GSH 5 mM (E1-a), SBLE and SP 20 vol% (E2-a), and SBLE, GSH 5 mM and SP 20 vol% (E3-a), respectively. The second portion was extended with SBLE to 100 million/ml. Both portions were cryopreserved in liquid nitrogen. Following thawing, the second portion was extended in the same manner to 50 million/ml and was separated into C-b, E1-b, E2-b, and E3-b, respectively. Each group was sampled in ten replicates immediately following thawing. Thawed samples were analyzed for viability (Hancock-2 stain), and velocity (Hamilton Thorne, USA). Each sample included at least 200 cells and the results were expressed in percent values (mean±SEM). Normality (Kolmogorov) and variance comparison (factorial-ANOVA) were performed in Statistica 8 with a significance level p&lt;0.05. E2-a (57.58% ±2.40) and E3-a (56.94% ±1.85) yielded significantly higher viability compared to the C-a (40.73 ±1.53). There were no significant differences between C-b (50.00% ±2.33), E1-b (43.61% ±1.37), E2-b (49.16% ±1.50), and E3-b (48.50% ±1.85). In conclusion, the addition of SBLE, GSH, and SP prior vs after cryopreservation has a significant effect on thawed ram sperm viability and velocity

PhysicoMechanical and Physico-Chemical Properties of Bio-Inert Composite Ceramics

Bio-inert ceramics are non-toxic, non-allergenic and non-carcinogenic materials which explain why these are frequently used as orthopedic and dental implants. Unfortunately, these are chemically inert and do not naturally form a direct link with the bone. The research carried studies micro/nanostructure properties and the porosity of the TiO2-Nb2O5 ceramics, used as biocompatible polymer matrix, prepared by different technological regimes. The morphology of the composite samples of TiO2-Nb2O5 was studied using scanning microscopy. The phase identification of the composites was carried by metallographic microscopy. Results obtained show the chemical composition, the technological parameters and the porosity determined, favors formation of sufficiently strong bond between the studied materials and vitreous carbon layers

A Possibility to Decrease the Sintering Temperature of Corundum Ceramics

The ceramics consisting of more than 95% Al2O3 is called corundum ceramics. The name comes from the name of the α-crystalline form of the aluminum oxide-corundum. The basic technological process influencing the properties of this ceramic is the temperature and the duration of the sintering process. Sintering aids are used to improve sintering and to control grain size. The possibility to use CaTiO3 as sintering aid is investigated. This substance lowers the sintering temperature with more than 100 oC and at the same time the mechanical properties are preserved. The compressive strength is more than 2000 MPa and the flexural strength is more than 200 MPa