Thin trading and estimation of systematic risk: An application of an error-correction model

Financial economics literature indicates that estimates for securities' systematic risk, i.e. the beta coefficients, are highly affected by infrequent trading. This is an especially serious problem in small security markets. In this study, the applicability of an error-correction model is investigated for modeling the risk behavior of thinly traded securities. The empirical results from a small stock market, i.e. the Helsinki Stock Exchange, indicate the estimated error-correction term to be highly dependent on the underlying trading frequency of the stock, while the direct effect is dependent merely on the market value of the firm. The model thus appears to produce useful information about the risk characteristics of thinly traded stocks.     

Role of the ionic reactions in teaching and research in Finland

Summary The status of ionic reactions in the chemistry curricula of the Finnish universities is outlined. In analytics their role is evidently changed. Qualitative analysis is no longer carried out by means of ionic reactions, but in modern instrumental methods of analysis these reactions are needed in sample preparation. Additionally, the ionic reactions are still important in teaching of analytical and inorganic chemistry. However, this topic should partly be taught already in the secondary school.     

Crystal structure, thermal behaviour, protonation and mass spectroscopic studies of racemic 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole hydrochlorides

The crystal structure, thermal behaviour, mass spectrum and protonation of 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole (medetomidine) hydrochloride have been investigated. The title compound crystallizes in both hydrated and anhydrous forms, and their structures have been determined by three-dimensional X-ray structure analysis. The crystals of the anhydrous form are monoclinic and those of the hydrated form (containing one hydrate water molecule) are triclinic with unit-cell dimensions: a = 23.861(9), b = 7.721(4), c = 22.037(9) A, beta = 140.20(4) degrees, Z = 8, and space group C2/c, and a = 7.841(4), b = 8.380(3), c = 12.743(6) A, alpha = 93.66(3), beta = 102.90(3), gamma = 116.85(3) degrees, Z = 2, and space group P1, respectively. Thermal decomposition of the title compound has been interpreted from the TG, DTG and DSC curves with the help of mass spectrometry. Medetomidine hydrochloride monohydrate decomposes in four stages. The first is dehydration at 45-100 degrees C, the second is evaporation of HCl and medetomidine base at 200-320 degrees C, and the third and fourth are decomposition at 340-570 degrees C. The protonation constant is 7.04 in aqueous 0.1 M NaClO4 (25 degrees C).     

Catalytic effect of sodium chloride on limestone calcination and sulphation — electron microscopy and eds studies

Thermogravimetric studies on the influence of sodium chloride on the kinetics of limestone sulphation were supported by scanning electron microscopy and energy dispersive X-ray microanalysis.On the basis of morphological observations on calcined and sulphated limestone and elemental microanalysis in an electron microprobe it was found that NaCl affects the sintering, favouring the formation of more compact structures of rounded crystallites during sulphation. Chlorine is largely lost during sulphation. Capacity of the sorbents under both TG and FBC conditions depends strongly on when and how the NaCl is introduced.

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Zusammenfassung In Verbindung mit Scanning Elektronenmikroskopie und Röntgenmikroanalyse wurden thermogravimetrische Untersuchungen des Einflusses von Natriumchlorid auf die Kinetik der Sulfierung von Kalkstein durchgeführt.Auf der Grundlage von morphologischen Beobachtungen an kalziniertem und sulfiertem Kalkstein und durch Elementarmikroanalyse in einem Elektronenstrahlmikroanalysator wurde festgestellt, daß NaCl das Sintern beeinflußt. Infolgedessen wird bei der Sulfierung die Entstehung von abgerundeten Kristalliten begünstigt. Chlor wird während der Sulfierung größtenteils abgegeben. Die Kapazität der Sorptionsmittel hängt sowohl bei TG als auch bei FBC stark davon ab, wann und wie das NaCl eingebracht wurde.

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The authors wistl to thank Prof. E. M. Bulewicz of the Technical University of Cracow for helpful discussions and Mr. S. Sivonen of the University of Oulu for making available the facilities the SEM and EDS-X-ray microanalysis at the Institute of Electron Optics.     

Determination of second-order susceptibility components of thin films by two-beam second-harmonic generation

We measure the susceptibility components of a poled polymer film by second-harmonic generation with two beams at the fundamental frequency. The technique allows the consistency of experimental data and the validity of the theoretical model used to analyze the results to be addressed. Our results are in agreement with the expected values, provided that the linear optical properties of the sample are properly included.     

Negative gastrointestinal contrast enhancement and image distortion induced by superparamagnetic particles at 0.02 Tesla

Gastrointestinal contrast enhancement and image distortion induced by superparamagnetic particles were evaluated in vitro and in rabbits at 0.02 Tesla. Test tubes containing 0.01–1.0 mg particles/ml were imaged in an oil or water bath in order to demonstrate the concentration-dependent signal void and image distortion in vitro at several pulse sequences. The lowest concentration of particles tested clearly decreased the signal intensity. Image distortion was observed when the concentration exceeded 0.07 mg/ml and was more pronounced on the T₂-weighted images. The in vitro T₂ relaxation time decreased from 122 ms to 56 ms with an increase in the particle concentration from 0.01 to 0.06 mg/ml. A loss of the GI-tract signal was observed in rabbits after the administration of 1 mg particles/kg, given as a 0.03 mg/ml suspension. At a dose of 20 mg/kg (0.6 mg/ml suspension) significant image distortion was observed.     

Quantum circuits for general multiqubit gates

We consider a generic elementary gate sequence which is needed to implement a general quantum gate acting on n qubits-a unitary transformation with 4(n) degrees of freedom. For synthesizing the gate sequence, a method based on the so-called cosine-sine matrix decomposition is presented. The result is optimal in the number of elementary one-qubit gates, 4(n), and scales more favorably than the previously reported decompositions requiring 4(n)-2(n+1) controlled NOT gates.     

Advantages of polarized two-beam second-harmonic generation in precise characterization of thin films

Polarized second-harmonic generation using two fundamental beams, instead of one, offers significant advantages for characterizing nonlinear optical thin films. The technique is more precise and allows the internal consistency of the results to be verified. The superiority of the two-beam arrangement over the traditional single-beam arrangement is demonstrated by determining the susceptibility tensors of Langmuir-Blodgett films. We show that, for a well-understood reference sample, the results obtained using two fundamental beams agree qualitatively with those obtained with a single fundamental beam, but are more precise. In a more complicated situation, however, the single-beam technique appears to work well but yields results that are, in fact, incorrect. The two-beam technique, instead, yields clearly inconsistent results, thereby highlighting systematic errors in the experimental arrangement or in the theoretical model used to interpret the results.     

Nonlinear optical technique for precise retardation measurements

We present a highly sensitive nonlinear optical technique to measure optical retardation. The technique is based on second-harmonic generation from thin films using two beams at the fundamental frequency. The sensitive polarization dependence of the process allows measuring optical retardation very precisely. The technique relies on fundamental symmetry principles and does therefore not require complicated experimental arrangement or data analysis. The technique was demonstrated by determining the retardation of a nominal half-wave plate to a precision and repeatability better than lambda/10(4).