Evaluation of the quality of clinical laboratories in the Slovak Republic: conceptual and contextual remarks

The paper demonstrates conceptual parallels and relationships between intellectual capital measurement methods and the evaluation of quality in clinical laboratories in the Slovak Republic. It explores further the contextual links of those parallels with the tangibility (or intangibility) of quality indicators of laboratory diagnostics. It also highlights the problems which laboratory staff in Slovakia are confronted with. Presented at the conference Quality in the Spotlight, March 2007, Antwerp, Belgium.     

UV light impact on ellagitannins and wood surface colour of European oak (Quercus petraea and Quercus robur)

Two European oak species (Q. petraea and Q. robur) have a high content of phenols which may participate in the alteration of colour upon UV irradiation. To study the photodegradation process of oak surfaces, the two oak species extractives, vescalagin, castalagin, ellagic acid and gallic acid were analysed quantitatively by HPLC before and after UV irradiation. Irradiation time was altered between 3, 24, 72, 96, 120, 144, 192 and 216 h. In parallel, any colour changes of Oak wood surface was followed after 120 h of UV-irradiation by measuring CIELAB parameters (DL*, Da*, Db* and DE*). We observed that 60% of total phenol content of extractives decreased after the maximal exposure time. Our findings also showed that castalagin and gallic acid were destroyed after 216 h and vescalagin and ellagic acid after 72 h. This study proves the photosenibility of oakwood extractives which, supplementary to lignin degradation, would strongly result in the discolouration of oak heartwood.     

Asymmetric conditional volatility in international stock markets

Recent studies show that a negative shock in stock prices will generate more volatility than a positive shock of similar magnitude. The aim of this paper is to appraise the hypothesis under which the conditional mean and the conditional variance of stock returns are asymmetric functions of past information. We compare the results for the Portuguese Stock Market Index PSI 20 with six other Stock Market Indices, namely the SP 500, FTSE 100, DAX 30, CAC 40, ASE 20, and IBEX 35. In order to assess asymmetric volatility we use autoregressive conditional heteroskedasticity specifications known as TARCH and EGARCH. We also test for asymmetry after controlling for the effect of macroeconomic factors on stock market returns using TAR and M-TAR specifications within a VAR framework. Our results show that the conditional variance is an asymmetric function of past innovations raising proportionately more during market declines, a phenomenon known as the leverage effect. However, when we control for the effect of changes in macroeconomic variables, we find no significant evidence of asymmetric behaviour of the stock market returns. There are some signs that the Portuguese Stock Market tends to show somewhat less market efficiency than other markets since the effect of the shocks appear to take a longer time to dissipate.     

Stylized facts in internal rates of return on stock index and its derivative transactions

Universal features in stock markets and their derivative markets are studied by means of probability distributions in internal rates of return on buy and sell transaction pairs. Unlike the stylized facts in normalized log returns, the probability distributions for such single asset encounters incorporate the time factor by means of the internal rate of return, defined as the continuous compound interest. Resulting stylized facts are shown in the probability distributions derived from the daily series of TOPIX, S & P 500 and FTSE 100 index close values. The application of the above analysis to minute-tick data of NIKKEI 225 and its futures market, respectively, reveals an interesting difference in the behavior of the two probability distributions, in case a threshold on the minimal duration of the long position is imposed. It is therefore suggested that the probability distributions of the internal rates of return could be used for causality mining between the underlying and derivative stock markets. The highly specific discrete spectrum, which results from noise trader strategies as opposed to the smooth distributions observed for fundamentalist strategies in single encounter transactions may be useful in deducing the type of investment strategy from trading revenues of small portfolio investors.     

Solitary wave solutions of nonlinear financial markets :data-modeling-concept-practicing

This paper seeks to solve the difficult nonlinear problem in financial markets on the complex system theory and the nonlinear dynamics principle, with the data-model-concept-practice issue-oriented reconstruction of the phase space by the high frequency trade data. In theory, we have achieved the differentiable manifold geometry configuration, discovered the Yang-Mills functional in financial markets, obtained a meaningful conserved quantity through corresponding space-time non-Abel localization gauge symmetry transformation, and derived the financial solitons, which shows that there is a strict symmetry between manifold fiber bundle and guage field in financial markets. In practical applications of financial markets, we have repeatedly carried out experimental tests in a fluctuant evolvement, directly simulating and validating the existence of solitons by researching the price fluctuations (society phenomena) using the same methods and criterion as in natural science and in actual trade to test the stock Guangzhou Proprietary and the futures Fuel Oil in China. The results demonstrate that the financial solitons discovered indicates that there is a kind of new substance and form of energy existing in financial trade markets, which likely indicates a new science paradigm in the economy and society domains beyond physics.      

Modeling and analysis of an agent-based model for Chinese stock market

We constructed an agent-based stock market model which concisely describe investors? heterogeneity and adaptability by introducing price sensitivity and feedback time. Under different parameters, the peak and fat-tail property of return distribution is produced and the obtained statistic values coincide with empirical results: the center peak exponents range from ?0.787 to ?0.661, and the tail exponents range from ?4.29 to ?2.37. Besides, long-term correlation in volatility is examined by DFA1 method, and the obtained exponent α is 0.803, which also coincides with the exponent of 0.78 found in real market.