Showing papers by "University of Maribor published in 2002"

Decision Trees: An Overview and Their Use in Medicine

Abstract: In medical decision making (classification, diagnosing, etc.) there are many situations where decision must be made effectively and reliably. Conceptual simple decision making models with the possibility of automatic learning are the most appropriate for performing such tasks. Decision trees are a reliable and effective decision making technique that provide high classification accuracy with a simple representation of gathered knowledge and they have been used in different areas of medical decision making. In the paper we present the basic characteristics of decision trees and the successful alternatives to the traditional induction approach with the emphasis on existing and possible future applications in medicine.

Observation of B̄0 → D(*)0 pp̄

Abstract: The B meson decay modes B → Dpp and B → D*pp have been studied using 29.4 fb - 1 of data collected with the Belle detector at KEKB. The B 0 → D 0 pp and B 0 → D* 0 pp decays have been observed for the first time with branching fractions B(B 0 → D 0 pp) = (1.18 ′ 0.15 ′ 0.16) X 10 - 4 and B(B 0 → D* 0 pp) = (1.20 + 0 . 3 3 - 0 . 2 9 ′ 0.21) X 10 - 4 . No signal has been found for the B + → D + pp and B + → D* + pp decay modes, and the corresponding upper limits at 90% C.L. are presented.

Modelling of simple and complex calcium oscillations

Abstract: This review provides a comparative overview of recent developments in the modelling of cellular calcium oscillations. A large variety of mathematical models have been developed for this wide-spread phenomenon in intra- and intercellular signalling. From these, a general model is extracted that involves six types of concentration variables: inositol 1,4,5-trisphosphate (IP3), cytoplasmic, endoplasmic reticulum and mitochondrial calcium, the occupied binding sites of calcium buffers, and the fraction of active IP3 receptor calcium release channels. Using this framework, the models of calcium oscillations can be classified into 'minimal' models containing two variables and 'extended' models of three and more variables. Three types of minimal models are identified that are all based on calcium-induced calcium release (CICR), but differ with respect to the mechanisms limiting CICR. Extended models include IP3--calcium cross-coupling, calcium sequestration by mitochondria, the detailed gating kinetics of the IP3 receptor, and the dynamics of G-protein activation. In addition to generating regular oscillations, such models can describe bursting and chaotic calcium dynamics. The earlier hypothesis that information in calcium oscillations is encoded mainly by their frequency is nowadays modified in that some effect is attributed to amplitude encoding or temporal encoding. This point is discussed with reference to the analysis of the local and global bifurcations by which calcium oscillations can arise. Moreover, the question of how calcium binding proteins can sense and transform oscillatory signals is addressed. Recently, potential mechanisms leading to the coordination of oscillations in coupled cells have been investigated by mathematical modelling. For this, the general modelling framework is extended to include cytoplasmic and gap-junctional diffusion of IP3 and calcium, and specific models are compared. Various suggestions concerning the physiological significance of oscillatory behaviour in intra- and intercellular signalling are discussed. The article is concluded with a discussion of obstacles and prospects.

Wiener Index of Hexagonal Systems

Abstract: The Wiener index W is the sum of distances between all pairs of vertices of a (connected) graph. Hexagonal systems (HS's) are a special type of plane graphs in which all faces are bounded by hexagons. These provide a graph representation of benzenoid hydrocarbons and thus find applications in chemistry. The paper outlines the results known for W of the HS: method for computation of W, expressions relating W with the structure of the respective HS, results on HS's extremal w.r.t. W, and on integers that cannot be the W-values of HS's. A few open problems are mentioned. The chemical applications of the results presented are explained in detail.

Observation of Double cc ̄ Production in e + e - Annihilation at (s)~10.6 GeV

Abstract: We report the observation of prompt $J/\ensuremath{\psi}$ via double $c\overline{c}$ production from the ${e}^{+}{e}^{\ensuremath{-}}$ continuum. In this process one $c\overline{c}$ pair fragments into a $J/\ensuremath{\psi}$ meson while the remaining pair either produces a charmonium state or fragments into open charm. Both cases have been experimentally observed. We find cross sections of $\ensuremath{\sigma}[{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\eta}}_{c}(\ensuremath{\gamma})]\ifmmode\times\else\texttimes\fi{}\mathcal{B}({\ensuremath{\eta}}_{c}\ensuremath{\rightarrow}\ensuremath{\ge}4\text{ }\text{ }\mathrm{\text{charged}})=({0.033}_{\ensuremath{-}0.006}^{+0.007}\ifmmode\pm\else\textpm\fi{}0.009)\text{ }\text{ }\mathrm{p}\mathrm{b}$ and $\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{D}^{*+}X)=({0.53}_{\ensuremath{-}0.15}^{+0.19}\ifmmode\pm\else\textpm\fi{}0.14)\text{ }\text{ }\mathrm{p}\mathrm{b}$ and infer $\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}c\overline{c})/\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}X)={0.59}_{\ensuremath{-}0.13}^{+0.15}\ifmmode\pm\else\textpm\fi{}0.12$. These results are obtained from a $46.2\text{ }\text{ }{\mathrm{f}\mathrm{b}}^{\ensuremath{-}1}$ data sample collected near the $\ensuremath{\Upsilon}(4S)$ resonance, with the Belle detector at the KEKB collider.

Study of three-body charmless B decays

Abstract: We report on a study of three-body charmless decays B+ => K+h+h-$ based on a 29.1 fb^{-1} data sample collected with the Belle detector. With no assumptions on the intermediate mechanisms, the following three-body branching fractions have been measured for the first time: Br(B+ => K+pi-pi+) = (55.6\pm5.8\pm7.7)x10^{-6} and Br(B+ => K+K-K+) = (35.3\pm3.7\pm4.5)x10^{-6}. We present the first observation of the decay B+ => f_0(980)K+ with a branching fraction product of Br(B+ => f_0(980)K+)xBr(f_0(980) => \pi+\pi-)= (9.6^{+2.5+1.5+3.4}_{-2.3-1.5-0.8})x10^{-6}. This is the first reported example of a B meson decay to a scalar pseudoscalar final state. We also report the first observation of B+ => K*(892)^0 pi+ decay with a branching fraction of Br(B+ => K*(892)^0 pi+) = (19.4^{+4.2+2.1+3.5}_{-3.9-2.1-6.8})x10^{-6}.

Improved measurement of mixing-induced CP violation in the neutral B meson system

Abstract: We present an improved measurement of the standard model CP violation parameter $\mathrm{sin}2{\ensuremath{\varphi}}_{1}$ (also known as $\mathrm{sin}2\ensuremath{\beta})$ based on a sample of $85\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. One neutral B meson is reconstructed in a $J/\ensuremath{\psi}{K}_{S}^{0},$ $\ensuremath{\psi}{(2S)K}_{S}^{0},$ ${\ensuremath{\chi}}_{c1}{K}_{S}^{0},$ ${\ensuremath{\eta}}_{c}{K}_{S}^{0},$ $J/\ensuremath{\psi}{K}^{*0},$ or $J/\ensuremath{\psi}{K}_{L}^{0}$ CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time interval between the two B meson decay points, we obtain $\mathrm{sin}2{\ensuremath{\varphi}}_{1}=0.719\ifmmode\pm\else\textpm\fi{}0.074(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.035(\mathrm{syst}).$

Compressed gases as alternative enzymatic-reaction solvents: a short review

Abstract: Application of supercritical fluids and liquid gases as an alternative reaction medium for enzyme-catalysed reactions is presented. The factors affecting the enzyme stability in supercritical fluids (effect of water activity, effect of pressure and temperature, number of pressurisation–depressurisation steps) and inhibition of enzymes are well documented with experimental results on hydrolases. An overview of our research on various types of HP enzymatic batch-stirred-tank-, continuous-packed-bed- and continuous-membrane reactors to obtain data on productivity and to evaluate the economy of the process is given.

Observation of the ηc(2S) in exclusive B → KKSK-π+ decays

Abstract: We report the observation of a narrow peak in the ${K}_{S}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ invariant mass distribution in a sample of exclusive $B\ensuremath{\rightarrow}K{K}_{S}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ decays collected with the Belle detector at the KEKB asymmetric ${e}^{+}{e}^{\ensuremath{-}}$ collider. The measured mass of the peak is $M=3654\ifmmode\pm\else\textpm\fi{}6(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\ifmmode\pm\else\textpm\fi{}8(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{c}^{2}$, and we place a 90% confidence level upper limit on the width of $\ensuremath{\Gamma}l55\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{c}^{2}$. The properties agree with heavy-quark potential model expectations for the ${\ensuremath{\eta}}_{c}(2S)$ meson, the $n=2$ singlet $S$ charmonium state.

Speed-sensorless sliding-mode torque control of an induction motor

Abstract: Novel induction motor control optimizing both torque response and efficiency is proposed in the paper. The main contribution of the paper is a new structure of rotor flux observer aimed at the speed-sensorless operation of an induction machine servo drive at both low and high speed, where rapid speed changes can occur. The control differs from the conventional field-oriented control. Stator and rotor flux in stator fixed coordinates are controlled instead of the stator current components in rotor field coordinates i/sub sd/ and i/sub sq/. In principle, the proposed method is based on driving the stator flux toward the reference stator flux vector defined by the input command, which are the reference torque and the reference rotor flux. The magnitude and orientation angle of the rotor flux of the induction motor are determined by the output of the closed-loop rotor flux observer based on sliding-mode control and Lyapunov theory. Simulations and experimental tests are provided to evaluate the consistency and performance of the proposed control technique.

The measurement of perceived differences in service quality — The case of health spas in Slovenia

Abstract: The authors concentrate on the importance of service quality elements in health spas. In the introduction the authors describe general characteristics of the health spa industry in Slovenia. They also point out the expanding emphasis on the service elements of products, their perceived quality and their influence upon the management practices of organisations. The main characteristics of the theoretical discussion on quality of services are presented, as well as the background of the research project.This 1999 study was a replication of part of a research project on the health spa industry in Slovenia conducted in 1991 using the SERVQUAL instrument. The project dealt with the assessment of the overall service quality in two health spas, the identification of important profiles of health spa service quality components and the identification of possible differences between important profiles of service quality components identified in 1991 and those seen in 1999.Most of the important differences in the stru...

LISA: An Interactive Environment for Programming Language Development

Abstract: The LISA system is an interactive environment for programming language development. From the formal language specifications of a particular programming language LISA produces a language specific environment that includes editors (a language-knowledgable editor and a structured editor), a compiler/interpreter and other graphic tools. The LISA is a set of related tools such as scanner generators, parser generators, compiler generators, graphic tools, editors and conversion tools, which are integrated by well-designed interfaces.

Observation of B± → p p̄ K±

Abstract: We report the observation of the decay mode $B^{\pm}\to p \bar{p} K^{\pm}$ based on an analysis of 29.4 fb$^{-1}$ of data collected by the Belle detector at KEKB. This is the first example of a $b\to s$ transition with baryons in the final state. The $p \bar{p}$ mass spectrum in this decay is inconsistent with phase space and is peaked at low mass. The branching fraction for this decay is measured to be ${\cal B}(B^{\pm}\to p \bar{p} K^{\pm}) =(4.3^{+1.1}_{-0.9}({\rm stat})\pm 0.5({\rm syst}))\times 10^{-6}.$ We also report upper limits for the decays $B^0\to p \bar{p} K_S$ and $B^{\pm}\to p \bar{p} \pi^{\pm}$.

Computational model for analysis of bending fatigue in gears

Abstract: A computational model for determination of service life of gears in regard to bending fatigue in a gear tooth root is presented. The fatigue process leading to tooth breakage is divided into crack initiation (Ni) and crack propagation (Np) period, where the complete service life is defined as N=Ni+Np . The strain-life method in the framework of the FEM method has been used to determine the number of stress cycles Ni required for the fatigue crack initiation. Gear tooth crack propagation was simulated using a FEM method based computer program which uses principles of linear elastic fracture mechanics. Paris equation is then used for the further simulation of the fatigue crack growth. The presented model is used for determination of service life of real spur gear made from through-hardened steel 42CrMo4.

1-perfect codes in Sierpiński graphs

Abstract: Sierpinski graphs S (n, κ) generalise the Tower of Hanoi graphs—the graph S (n, 3) is isomorphic to the graph Hn of the Tower of Hanoi with n disks. A 1-perfect code (or an efficient dominating set) in a graph G is a vertex subset of G with the property that the closed neighbourhoods of its elements form a partition of V (G). It is proved that the graphs S (n, κ) possess unique 1-perfect codes, thus extending a previously known result for Hn. An efficient decoding algorithm is also presented. The present approach, in particular the proposed (de)coding, is intrinsically different from the approach to Hn.

Miniature fiber optic pressure sensor for medical applications

Abstract: Presents a theoretical description, fabrication and experimental investigation of miniature optical fiber pressure sensor for invasive measurement of blood pressure. Sensor measures only 125 /spl mu/m in diameter. The essential element is thin polymer diaphragm that is positioned inside a hollow end of the optical fiber. The cavity at the fiber end is made by wet etching in diluted HF acid. Thus the Fabry-Perot interferometer is formed between the inner fiber-cavity interface and the diaphragm. Deflection of the diaphragm and so pressure magnitude is determined by reading the reflectance spectrum of the sensing Fabry-Perot interferometer using broadband illumination. The configuration of Fabry-Perot interferometer at the optical fiber end makes sensor immune from bending of optical fiber and optical power fluctuations of light source. We deployed sensor prototype from 125 /spl mu/m-diameter optical fiber. It is optimized for human blood pressure range, namely from 0 to 40 kPa (0 to 300 mmHg) with 1 mmHg resolution. Our fabrication technique offers simple and low-cost disposable medical pressure sensor production.

Total charge-changing and partial cross-section measurements in the reactions of ∼ 110 – 250 M e V / n u c l e o n 12 C in carbon, paraffin, and water

Abstract: Total charge-changing cross sections and cross sections for the production of B and Be fragments were directly measured for reactions induced by $\ensuremath{\sim}110--250 \mathrm{M}\mathrm{e}\mathrm{V}/\mathrm{n}\mathrm{u}\mathrm{c}\mathrm{l}\mathrm{e}\mathrm{o}\mathrm{n}{ }^{12}\mathrm{C}$ ions in C, ${\mathrm{CH}}_{2},$ and ${\mathrm{H}}_{2}\mathrm{O}$ targets. Etched track detector (CR-3) was used, together with an automatic track measuring system and a track matching algorithm, to count and to identify the primary and secondary particles. A comparison of the present data and of previously measured cross sections with model predictions is carried out. For the total charge-changing cross section, a model developed at NASA gives the best agreement with the present results (about 3% on the average). However, for the production of fragments, the results of models deviate on average for all systems studied by 9--58 % from the data presented in this work for $Z=5$ and by 5--47 % for $Z=4.$ The model known as NUCFRG2 is the most reliable in giving the closest values for fragmentation cross sections, 9 and 5% for B and Be fragments, respectively, for the systems studied in this work.

Determination of the adsorption character of cellulose fibres using surface tension and surface charge

Abstract: The reactivity and adsorption properties of cellulose fibres are critical for successful treatment because behavior during the finishing process is determined by both structure and surface properties The fine structure of natural cellulose fibres ie cotton, is different from the regular viscose, modal and new types of regenerated cellulose fibres ie lyocell, which are clarified by different hydrophilic/hydrophobic character of fibres and different adsorption properties Tensiometry, seldom used in fibre characterization was used to obtain the differences in the adsorption properties of different cellulose fibres The surface tension, contact angle and adsorption were measured, and then compared with various methods for determining water adsorption Currently some additional methods especially sensitive to surface properties (electrokinetic properties of fibres) are being applied in order to characterize the adsorption character and reactivity of the fibre surfaces The streaming potential was measured due to the fact that the interaction properties are strongly influenced by electric charges on the surface, and from these values the zeta potential (ζ) was calculated as a function of the pH and the surfactant concentration in the liquid phase As with the results of fibre reactivity and adsorption properties obtained by conventional methods, the electrokinetic character of the materials and their adsorption ability determined using the tensiometry also show the same phenomena The natural fibres have the smaller hydrophilic character and they are less reactive than the regenerated ones, so the ζmax of cotton is the highest and the contact angle ϕ the greatest [1, 2, 3]

Trophoblastic interferon-gamma: current knowledge and possible role(s) in early pig pregnancy.

Abstract: In the pig as in ruminant species, the implantation of the elongated conceptus - the embryo with its associated membranes - onto the maternal uterus is accompanied by an intense secretion of interferon (IFN), which culminates at day 15 of development. It has been shown that in fact the pig trophectoderm - the polarized epithelium which lines the conceptus - simultaneously secretes two types of interferons: IFN-gamma (IFN-gamma), which is the more abundant species, is produced in very substantial amounts. Another IFN is also secreted, which happens to be a novel type I IFN, now named IFN-delta. It was previously shown that the uterus is the most probable target of the pig trophoblastic IFNs, since no autocrine effect was found on the trophoblast. It has also been shown that, unlike for the ruminant species, the pig trophoblastic IFNs do not play an apparent role in the so-called maternal recognition of pregnancy. We have focused this review on IFN-gamma, because first, it is the major species secreted and secondly, IFN-gamma has various regulatory effects on different tissues, including lymphoid cells. We particularly address the question of the possible role of trophoblastic IFN-gamma in early pregnancy, in the light of the known biological functions of human and mouse IFN-gamma.

Intelligent tool path generation for milling of free surfaces using neural networks

Abstract: The presented paper has an intention to show how with the help of Artificial Neural Network (ANN), the prediction of milling tool-path strategy could be made in order to establish which milling path strategy or their sequence will show the best results (will be the most appropriate) at free surface machining, according to set technological aim. In our case the best possible surface quality of machined surface was taken as the primary technological aim. Configuration of used Neural Network (NN) is presented, and the whole procedure is shown on an example of mould, for producing light switches. The verification of machined surface quality, according to average mean roughness, Ra, is also being done, and compared with the NN predicted results.

Relations between the motor and cognitive dimensions of preschool girls and boys.

Abstract: The aim of this study was to compare relations between latent motor dimensions and cognitive abilities of preschool boys and girls (N=665, age: 5 to 6 years). The psychological part of the testing was implemented with the Test Razkol. For the assessment of motor abilities 28 tests were given. The associations of motor and cognitive variables were estimated by multiple regression analysis, which showed positive and significant associations between the latent motor variables and the cognitive variable for both boys and girls. On both sexes, the motor dimensions with the strongest associations with the cognitive abilities are those of coordination and the speed of movement. Despite some differences between boys and girls, they still have a lot in common since the most important latent motor dimensions prevailing in the connection between motor and cognitive dimensions are similar.