ASPECTS REGARDING THE INFLUENCE OF VOLATILITY ON THE OPTION’S PRICE

The most important advantage of the option transactions resides in the fact that it offers, through the existing relations between the derivatives market and the spot market, improved solutions of portfolio management, the put options constituting an insurance policy against the decrease of the prices, and the call options acting as a guarantee for the purchase of the support asset at the pre-set price. The volatility represents a measure of the size of the price fluctuations of the support asset and thus it can be assimilated with a random variable. The analysis of the essential factors that influence the price of the option contracts has demonstrated that the volatility of the support asset's price shows how risky it is for it to be one of the main and most difficult to determine factor, because this is the only parameter that is not known exactly at the moment of the contract conclusion. Under these conditions, due to the profound importance of volatility in the option evaluation and due to the fact that volatility is difficult to estimate, observe or predict, we must model it as a random variable for many of the option contracts for which the model of constant volatility (as the Black Scholes model is) is inadequate..options contract, historical volatility, stochastic volatility, exercise price,standard deviation

THE FINANCIAL MANAGEMENT OF THE SMALL AND MEDIUM SIZED COMPANIES IN ROMANIA

The objective of the paper is to identify the possibilities and promotion limits of the financial management in the small and medium sized companies in Romania starting from the concepts expressed in the literature and expressed in the concrete situations in the Romanian economy practice. We have also presented the role of the financial management in small and medium sized companies and the risk management objective of financial management considering that the risk is a fundamental component of a strategic and tactical decision. At the end of the paper we have presented the conclusions stemming from the study, the basic one being that there is a beginning in the promotion and applicability of theoretical elements of financial management in small and medium sized companies in Romania together with the European integration.small and medium sized companies, financial management, investment, risk, economic profitability

First-principles molecular-dynamics simulations of a hydrous silica melt: Structural properties and hydrogen diffusion mechanism

We use {\it ab initio} molecular dynamics simulations to study a sample of liquid silica containing 3.84 wt.% H$_2$O.We find that, for temperatures of 3000 K and 3500 K,water is almost exclusively dissolved as hydroxyl groups, the silica network is partially broken and static and dynamical properties of the silica network change considerably upon the addition of water.Water molecules or free O-H groups occur only at the highest temperature but are not stable and disintegrate rapidly.Structural properties of this system are compared to those of pure silica and sodium tetrasilicate melts at equivalent temperatures. These comparisons confirm the picture of a partially broken tetrahedral network in the hydrous liquid and suggest that the structure of the matrix is as much changed by the addition of water than it is by the addition of the same amount (in mole %) of sodium oxide. On larger length scales, correlations are qualitatively similar but seem to be more pronounced in the hydrous silica liquid. Finally, we study the diffusion mechanisms of the hydrogen atoms in the melt. It turns out that HOSi$_2$ triclusters and SiO dangling bonds play a decisive role as intermediate states for the hydrogen diffusion.Comment: 25 pages, 18 figures. submitte

Novel Gas Phase Route Toward Patterned Deposition of Sputter-Free Pt/Al Nanofoils

This article reports a new approach toward fabrication and directed assembly of nanoparticulate reactive system (Nanofoils) on patterned substrates. Different from current state-of-the-art, gas phase electrodeposition uses nanoparticles instead of atoms to form densely packed multilayered thin films at room temperature-pressure. On ignition, the multilayer system undergoes an exothermic self-propagating reaction. The numerous contact points between two metallic nanoparticulate layers aid in high heat release. Sub-10-nm Platinum (Pt) and Aluminum (Al) particles are synthesized through cathode erosion of metal electrodes in a flow of pure nitrogen gas (spark ablation). Pt/Al bilayer stacks with total thickness of 3–8 µm undergo self-propagating reaction with a 10.3 mm s−1 wavefront velocity on local ignition. The reaction wavefront is captured using high speed videography. Calorimetry studies reveal two exothermic peaks suggesting Pt/Al alloy formation. The peak at 135 °C has a higher calorific value of 150 mW g−1 while the peak at 400 °C has a 12 mW g−1 exothermic peak. X-ray diffraction study shows reaction-products are cubic Al2Pt with small quantities of orthorhombic Al6Pt and orthorhombic AlPt2. Electron microscopy studies help draw a correlation between film morphology, bimetallic interface, nanoparticle oxidation, and self-propagating reaction kinetics that is significant in broadening our understanding towards nanoparticulate reactive systems

Comparative classical and ab initio Molecular Dynamics study of molten and glassy germanium dioxide

A Molecular Dynamics (MD) study of static and dynamic properties of molten and glassy germanium dioxide is presented. The interactions between the atoms are modelled by the classical pair potential proposed by Oeffner and Elliott (OE) [Oeffner R D and Elliott S R 1998, Phys. Rev. B, 58, 14791]. We compare our results to experiments and previous simulations. In addition, an ab initio method, the so-called Car-Parrinello Molecular Dynamics (CPMD), is applied to check the accuracy of the structural properties, as obtained by the classical MD simulations with the OE potential. As in a similar study for SiO2, the structure predicted by CPMD is only slightly softer than that resulting from the classical MD. In contrast to earlier simulations, both the static structure and dynamic properties are in very good agreement with pertinent experimental data. MD simulations with the OE potential are also used to study the relaxation dynamics. As previously found for SiO2, for high temperatures the dynamics of molten GeO2 is compatible with a description in terms of mode coupling theory.Comment: 27 pages, 16 figure

The Role of Information Centres in Promoting Tourist Destinations. Case Study:Tourist Information Centre Brasov

The main purpose of this paper is represented by the developing of proposals for improving the activity of Tourist Information Centre (TIC) in Braşov, starting from the fact that it has a very important role in promoting Braşov county. In the first part of the paper we focused on the theoretical concepts related to our topic, whereas in the second part we applied the benchmarking method for comparisons between three Tourist Information Centres in the world: Riga (Latvia), Girona (Spain) and Manhattan (USA), for adopting the best practices learned in our proposals to improve the activity of TIC in Braşov. In order to analyze the activity of TIC Braşov, we used the mystery consumer technique. The last part contains the conclusions and our proposals for improving the activity of TIC Braşov

Structural properties of lithium and sodium tetrasilicate glasses: Molecular dynamics simulations versus NMR experimental and first-principles data

International audienceIn this work we present the structural properties of lithium tetrasilicate glass (LS4) obtained by combined classical and Car-Parrinello molecular dynamics simulations. The computed features are compared with corresponding experimental results as well as to those obtained for sodium tetrasilicate glass (NS4) models generated using the same approach, and containing the some percentage of alkali oxide. The ab initio description improves the comparison of the structural characteristics with experimental data, in particular concerning the Li-O, Si-Li and Si-Si bond lengths. The influence of the network modifier nature on the relevant structural parameters is further examined in terms of their correlations to the first-principles calculated NMR parameters of our glassy models. For both glasses, 29Si MAS NMR measurements are reported and the obtained experimental spectra are compared to the theoretical ones

Bimodal distribution of Si-O-Si angles in sodo-silicate glasses

Polarized Raman scattering is performed in a series of sodo-silicate glasses. The Si–O–Si inter-tetrahedral angle and its distribution are extracted using a model developed previously for densified silica, and the result are compared to ab initio atomistic calculations. The two techniques reveal a reduction of the most probable angle of about 0.30°/mol% of Na2O, but the shape of the angular distributions are different. The results suggest that Raman scattering enhances a specific angular distribution of Si–O–Si bridges, likely those close to sodium atoms, highlighting local angular heterogeneities