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Search Results: 1 - 10 of 494 matches for " Andras Szatmari "
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Mid-term echocardiographic follow up of left ventricular function with permanent right ventricular pacing in pediatric patients with and without structural heart disease
Tchavdar Shalganov, Dora Paprika, Radu Vatasescu, Attila Kardos, Attila Mihalcz, Laszlo Kornyei, Andras Szatmari, Tamas Szili-Torok
Cardiovascular Ultrasound , 2007, DOI: 10.1186/1476-7120-5-13
Abstract: A group of 99 pediatric patients with previously implanted pacemaker was studied retrospectively. Forty-three patients (21 males) had isolated congenital complete or advanced atrioventricular block. The remaining 56 patients (34 males) had pacing indication in the presence of structural heart disease. Thirty-two of them (21 males) had isolated structural heart disease and the remaining 24 (13 males) had complex congenital heart disease. Patients were followed up for an average of 53 ± 41.4 months with 12-lead electrocardiogram and transthoracic echocardiography. Left ventricular shortening fraction was used as a marker of ventricular function. QRS duration was assessed using leads V5 or II on standard 12-lead electrocardiogram.Left ventricular shortening fraction did not change significantly after pacemaker implantation compared to preimplant values overall and in subgroups. In patients with complex congenital heart malformations shortening fraction decreased significantly during the follow up period. (0.45 ± 0.07 vs 0.35 ± 0.06, p = 0.015). The correlation between the change in left ventricular shortening fraction and the mean increase of paced QRS duration was not significant. Six patients developed dilated cardiomyopathy, which was diagnosed 2 months to 9 years after pacemaker implantation.Chronic right ventricular pacing in pediatric patients with or without structural heart disease does not necessarily result in decline of left ventricular function. In patients with complex congenital heart malformations left ventricular shortening fraction shows significant decrease.Chronic right ventricular (RV) apical pacing alters unfavorably left ventricular (LV) electrical activation, mechanical contraction, cardiac output, myocardial perfusion and histology. Permanent RV pacing may have detrimental effect on LV function and may promote to heart failure in adult patients with LV dysfunction [1-10]. The effect of chronic RV apical pacing on LV performance in pediatric pati
Review of the Book “Optimization in Computer Engineering—Theory and Applications”: Chapter 8—Applying Graph Coloring to Frequency Assignment  [PDF]
Andras Orban
Wireless Engineering and Technology (WET) , 2012, DOI: 10.4236/wet.2012.32008
Abstract: This book focuses on the relationship between theory and applications of various optimization problems in computer engineering. In the first half of the book the theoretical foundations are presented, such as some selected graph algorithms, integer linear programming and complexity theory. The second half of the book brings the theory closer to the reader by applying them to real-world optimization problems. Its aim is to bridge the often significant gap between theory and applications bringing additional value to both: the theory becomes more interesting in light of a possible application and understanding the hardness and possible solutions of the real-world problem definitely benefits from a strong theoretical background. Chapter 8 is a good example of the above. Here the authors present several versions of the frequency assignment problem (FAP), which is an important practical optimization problem arising in wireless network design. It is shown how FAP can be reduced to the earlier presented graph coloring problem. It is interesting to note that often the practical problem needs significant simplification in order to fit into the model that the theory is able to handle, or the theoretical problem needs to be extended to be able to model the needs of the practical application. Various generalizations of the simple graph coloring problem such as list coloring and T-coloring are introduced to model the constraints of the FAP. With this reduction the specific engineering problem can be han-dled through well-understood mathematical models. Besides showing the reduction to the graph coloring problem, the authors apply a graph coloring solver on industry benchmark FAP instances to further understand the characteristics of the real-world FAP. They show that there are significant differences in the difficulty of the problem on random and real-world graphs and that the parameters of the particular instance play a crucial role in the hardness of the problem. They show that the FAPs show a phase transition property in every input parameter, ie. there is a critical parameter combination where the problem gets extremely hard, but otherwise the problem can be solved relatively easily even on large real-world networks. Readers will surely benefit from the unique nature of the book that brings theory and applications close together in a well-understandable yet theoretically solid way.
INFLUEN A ORA ELOR CLUJ-NAPOCA I ORADEA ASUPRA STRUCTURII COMUNIT ILOR ZOOBENTONICE DIN R URILE SOME UL MIC I CRI UL REPEDE
Tunde Szatmari,Florina Bolos
Annals of West University of Timi?oara : Series of Biology , 1999,
Abstract: The structure and diversity of stream communities represent a biomonitoring pathway of aquatic ecosystems. The macroinvetebrate benthonic groups are important features used in monitoring of the polluted waters. The present study consists in a general presentation of zoobenthonic communities of Somesul Mic and Crisul Repede Rivers and of alterations in their structure due to Cluj-Napoca town and, respectively, Oradea town. Three quantitative samples were collected at two locations on Somesul Mic River (Gilau-upstream to Cluj-Napoca and Apahida-downstream to Cluj-Napoca) and two locations on Crisul Repede River (Fughiu-upstream to Oradea and Cheresig-downstream to Oradea), in august and october 1997. Water temperature, the current velocity, oxygen saturation, pH and conductivity were measured in the river. There are considerable differencies in community structure of the four sampling sites. The diversity of macroinvertebrate groups at the locations upstream to urban centers is greater than downstream, both in summer and in autumn. The General Biotic Index exhibits decreasing values along the two stream sectors (Gilau-Apahida and Fughiu-Cheresig) which enhance the affirmation that the two urban and industrial centers are the most important sources of rivers’disturbation.
Symmetry analysis of a system of modified shallow-water equations
Simon Szatmari,Alexander Bihlo
Physics , 2012,
Abstract: We revise the symmetry analysis of a modified system of one-dimensional shallow-water equations (MSWE) recently considered by Raja Sekhar and Sharma [Commun. Nonlinear Sci. Numer. Simulat. 20 (2012) 630-636]. Only a finite dimensional subalgebra of the maximal Lie invariance algebra of the MSWE, which in fact is infinite dimensional, was found in the aforementioned paper. The MSWE can be linearized using a hodograph transformation. An optimal list of inequivalent one-dimensional subalgebras of the maximal Lie invariance algebra is constructed and used for Lie reductions. Non-Lie solutions are found from solutions of the linearized MSWE.
Heating, Efficacy and Dose of Local Hyperthermia  [PDF]
Oliver Szasz, Andras Szasz
Open Journal of Biophysics (OJBIPHY) , 2016, DOI: 10.4236/ojbiphy.2016.61002
Abstract: Hyperthermia in oncology needs a definite dose which fixes well the clinical protocols. The temperature is far not a dose, it is mass independent. The half of the mass has the same temperature in equilibrium, so the basic criteria of the dose mass-dependence are lost. The energy could be a great option for dosing, (like it is in radiation therapies by Gy) but it has numerous drawbacks. These are discussed in this paper, trying to unify the dosing of ionizing and non-ionizing radiations.
Similarities of Modulation by Temperature and by Electric Field  [PDF]
Gyula Vincze, Andras Szasz
Open Journal of Biophysics (OJBIPHY) , 2018, DOI: 10.4236/ojbiphy.2018.83008
Abstract: Glycolytic oscillation is one of the first observed and described nonlinear phenomena in living objects. Our recent paper points out the similarity of the temperature and outer electric field to influence this oscillation. The electric field is absorbed and changes the molecules. Similarly to the effect of heating, molecules have various structural, dynamical and chemical changes promoted by electric field. The changes sometimes happen without increasing the temperature. Temperature, as the average energy of the included particles, has various kinds of “waste” energy used to heat up the particles which do not participate in the desired changes. The inaccuracy of the effects of temperature growth in local molecular changes could be remarkably high and could be corrected by the well-applied electric field absorption.
Fluctuations Hypothesize the New Explanation of Meridians in Living Systems  [PDF]
Gyula Peter Szigeti, Andras Szasz
Open Journal of Biophysics (OJBIPHY) , 2019, DOI: 10.4236/ojbiphy.2019.91004
Abstract: Biosystems are complex. Their physiology is well-controlled with various negative feedback signals and processes, it describes by opposite interfering effects which are characterized in the Eastern philosophy by Yin-Yang (Y-Y) pairs. Y-Y pairs could be described by the promoter-suppressor pairs in a wide range of physiologic signals creating the homeostasis of the complex system. This type of control appears as fluctuations from the average (mean) value of the signal. The mean carries an ineluctable fluctuation (called pink-noise or 1/f noise). All signals in homeostasis have equal entropy (SE = 1.8), which is the character of the complex equilibrium. The various controlling opposite signals (Y-Y) have different time-scales which change by aging. The processes with smaller time-scale are degraded by aging, but the pink-noise ensures that the deviations of the signals of the healthy homeostatic system remain constant. Meridians are connected to the general transport systems that combined the material and the information transport with the considerable transport networks, like blood, lymph, nerve, cell-junctions, mesenchymal “ground substance” cytoskeletons. The meridians in this meaning only virtual line averaged from multiple realized paths to connect two acupuncture points by the material, energy and information transport processes. The meridian network is designed by various coupling points (acupoints), which could be perturbed by actuating stimulus. Our objective is to describe the meridian system from complexity point of view.
A Bayesian Interpretation of the Particle Swarm Optimization and Its Kernel Extension
Peter Andras
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0048710
Abstract: Particle swarm optimization is a popular method for solving difficult optimization problems. There have been attempts to formulate the method in formal probabilistic or stochastic terms (e.g. bare bones particle swarm) with the aim to achieve more generality and explain the practical behavior of the method. Here we present a Bayesian interpretation of the particle swarm optimization. This interpretation provides a formal framework for incorporation of prior knowledge about the problem that is being solved. Furthermore, it also allows to extend the particle optimization method through the use of kernel functions that represent the intermediary transformation of the data into a different space where the optimization problem is expected to be easier to be resolved–such transformation can be seen as a form of prior knowledge about the nature of the optimization problem. We derive from the general Bayesian formulation the commonly used particle swarm methods as particular cases.
Estabilizaci 3n y Precios Relativos: Chile 1982-1991 Estabilizaci 3n y Precios Relativos: Chile 1982-1991
Andras Uthoff
Revista de Análisis Económico (RAE) , 1993,
Abstract: Estabilización y Precios Relativos: Chile 1982-1991 Chile, as other countries in the region, has reduced inflation rates to a two digit level varying within the range of 10 to 30 per cent. These rates are considered persistent and there is the political will to make them converge to levels prevailing in developed countries. This paper explores one of the implicit policy dilemmas surrounding this issue. Along with stabilization efforts, relative factor prices tend to move away from the values expected by participants in factor markets. This generares lack of confidence regarding the sustainability of the stabilization program. By means of a simple model, the paper shows that the distribution of benefics arising from increases in productivity affects relative prices and has important effects on the level at which inflation rates converge. The instruments used to produce such changes have additional effects on the variance of inflation rates.
Maziyi Silmek: Bosna-Hersek'teki Kütüphanelerin ve Ar ivlerin Tahribi
Andras Riedlmayer
Türk Kütüphanecili?i , 1995,
Abstract:
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