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Search Results: 1 - 10 of 293605 matches for " Péter T. Nagy "
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Schreier decomposition of loops
Péter T. Nagy
Mathematics , 2015,
Abstract: The aims of this paper are to find algebraic characterizations of Schreier loops and explore the limits of the non-associative generalization of the theory of Schreier extensions. A loop can have Schreier decomposition with respect to a normal subgroup if and only if the subgroup is the middle and right nuclear. In this case the conjugation by elements of the loop induces inner automorphisms on the normal subgroup if and only if the subgroup commutes with a suitable left transversal through the identity. Schreier loops which are Schreier extensions of the same loop by the same normal subgroups are characterized.
The method of double chains for largest families with excluded subposets
Péter Burcsi,Dániel T. Nagy
Mathematics , 2012,
Abstract: For a given finite poset $P$, $La(n,P)$ denotes the largest size of a family $\mathcal{F}$ of subsets of $[n]$ not containing $P$ as a weak subposet. We exactly determine $La(n,P)$ for infinitely many $P$ posets. These posets are built from seven base posets using two operations. For arbitrary posets, an upper bound is given for $La(n,P)$ depending on $|P|$ and the size of the longest chain in $P$. To prove these theorems we introduce a new method, counting the intersections of $\mathcal{F}$ with double chains, rather than chains.
Péter NAGY,Imre HOLB
Journal of Central European Agriculture , 2006,
Abstract: Macronutrient contents of soil and apple leaves were investigated in an organic apple orchard in Eastern Hungary in 2002-2004. Soil samples were taken from 0-20 cm depth in April and October. The macronutrient content of leaves was measured on cvs. Jonagold, Mutsu, Idared, Red Elstar, Egri Piros, Reka, and Remo at six assessment dates (from April to September). The macronutrient contents of N, P, K, S, Ca and Mg were measured in both soil and leaf samples, then macronutrient ratios were calculated from the obtained results. The results showed that younger leaves contained more N and P than older ones. K and Ca contents of leaves decreased until July, then increased slightly, and decreased again. A continuous decrease of the S content of leaves was observed until August. The Mg content of leaves increased until June, then decreased in July and then increased again. Macronutrient values were dependent on cultivar. Calculated macronutrient ratios showed that the nutrient supply of soil was not optimal in the orchard.
A Morphological Study of Retinal Changes in Unilateral Amblyopia Using Optical Coherence Tomography Image Segmentation
Andrea Szigeti, Erika Tátrai, Anna Szamosi, Péter Vargha, Zoltán Zsolt Nagy, János Németh, Delia Cabrera DeBuc, Gábor Márk Somfai
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088363
Abstract: Objective The purpose of this study was to evaluate the possible structural changes of the macula in patients with unilateral amblyopia using optical coherence tomography (OCT) image segmentation. Patients and Methods 38 consecutive patients (16 male; mean age 32.4±17.6 years; range 6–67 years) with unilateral amblyopia were involved in this study. OCT examinations were performed with a time-domain OCT device, and a custom-built OCT image analysis software (OCTRIMA) was used for OCT image segmentation. The axial length (AL) was measured by a LenStar LS 900 device. Macular layer thickness, AL and manifest spherical equivalent refraction (MRSE) of the amblyopic eye were compared to that of the fellow eye. We studied if the type of amblyopia (strabismus without anisometropia, anisometropia without strabismus, strabismus with anisometropia) had any influence on macular layer thickness values. Results There was significant difference between the amblyopic and fellow eyes in MRSE and AL in all subgroups. Comparing the amblyopic and fellow eyes, we found a statistically significant difference only in the thickness of the outer nuclear layer in the central region using linear mixed model analysis keeping AL and age under control (p = 0.032). There was no significant difference in interocular difference in the thickness of any macular layers between the subgroups with one-way between-groups ANCOVA while statistically controlling for interocular difference in AL and age. Conclusions According to our results there are subtle changes in amblyopic eyes affecting the outer nuclear layer of the fovea suggesting the possible involvement of the photoreceptors. However, further studies are warranted to support this hypothesis.
Patterns, transitions and the role of leaders in the collective dynamics of a simple robotic flock
Norbert Tarcai,Csaba Virágh,Dániel ábel,té Nagy,Péter L. Várkonyi,Gábor Vásárhelyi,Tamás Vicsek
Physics , 2012, DOI: 10.1088/1742-5468/2011/04/P04010
Abstract: We have developed an experimental setup of very simple self-propelled robots to observe collective motion emerging as a result of inelastic collisions only. A circular pool and commercial RC boats were the basis of our first setup, where we demonstrated that jamming, clustering, disordered and ordered motion are all present in such a simple experiment and showed that the noise level has a fundamental role in the generation of collective dynamics. Critical noise ranges and the transition characteristics between the different collective patterns were also examined. In our second experiment we used a real-time tracking system and a few steerable model boats to introduce intelligent leaders into the flock. We demonstrated that even a very small portion of guiding members can determine group direction and enhance ordering through inelastic collisions. We also showed that noise can facilitate and speed up ordering with leaders. Our work was extended with an agent-based simulation model, too, and high similarity between real and simulation results were observed. The simulation results show clear statistical evidence of three states and negative correlation between density and ordered motion due to the onset of jamming. Our experiments confirm the different theoretical studies and simulation results in the literature about collision-based, noise-dependent and leader-driven self-propelled particle systems.
Gene expression and activity of cartilage degrading glycosidases in human rheumatoid arthritis and osteoarthritis synovial fibroblasts
Mária Pásztói, Gy?rgy Nagy, Pál Géher, Tamás Lakatos, Kálmán Tóth, Károly Wellinger, Péter Pócza, Bence Gy?rgy, Marianna C Holub, ágnes Kittel, Krisztina Pálóczy, Mercédesz Mazán, Péter Nyirkos, András Falus, Edit I Buzas
Arthritis Research & Therapy , 2009, DOI: 10.1186/ar2697
Abstract: Expressions of β-D-hexosaminidase, β-D-glucuronidase, hyaluronidase, sperm adhesion molecule 1 and klotho genes were measured in synovial fibroblasts and synovial membrane samples of patients with rheumatoid arthritis and osteoarthritis by real-time PCR. β-D-Glucuronidase, β-D-glucosaminidase and β-D-galactosaminidase activities were characterized using chromogenic or fluorogenic substrates. Synovial fibroblast-derived microvesicles were also tested for glycosidase activity.According to our data, β-D-hexosaminidase, β-D-glucuronidase, hyaluronidase, and klotho are expressed in the synovial membrane. Hexosaminidase is the major glycosidase expressed within the joints, and it is primarily produced by synovial fibroblasts. HexA subunit gene, one of the two genes encoding for the alpha or the beta chains of hexosaminidase, was characterized by the strongest gene expression. It was followed by the expression of HexB subunit gene and the β-D-glucuronidase gene, while the expression of hyaluronidase-1 gene and the klotho gene was rather low in both synovial fibroblasts and synovial membrane samples. Tumor growth factor-β1 profoundly downregulated glycosidase expression in both rheumatoid arthritis and osteoarthritis derived synovial fibroblasts. In addition, expression of cartilage-degrading glycosidases was moderately downregulated by proinflammatory cytokines including TNFα, IL-1β and IL-17.According to our present data, glycosidases expressed by synovial membranes and synovial fibroblasts are under negative regulation by some locally expressed cytokines both in rheumatoid arthritis and osteoarthritis. This does not exclude the possibility that these enzymes may contribute significantly to cartilage degradation in both joint diseases if acting in collaboration with the differentially upregulated proteases to deplete cartilage in glycosaminoglycans.Rheumatoid arthritis (RA) is a chronic, progressive systemic autoimmune disease that affects approximately 1% of the adult po
Role of Tachykinin 1 and 4 Gene-Derived Neuropeptides and the Neurokinin 1 Receptor in Adjuvant-Induced Chronic Arthritis of the Mouse
éva Borbély, Zsófia Hajna, Katalin Sándor, László Kereskai, István Tóth, Erika Pintér, Péter Nagy, János Szolcsányi, John Quinn, Andreas Zimmer, James Stewart, Christopher Paige, Alexandra Berger, Zsuzsanna Helyes
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061684
Abstract: Objective Substance P, encoded by the Tac1 gene, is involved in neurogenic inflammation and hyperalgesia via neurokinin 1 (NK1) receptor activation. Its non-neuronal counterpart, hemokinin-1, which is derived from the Tac4 gene, is also a potent NK1 agonist. Although hemokinin-1 has been described as a tachykinin of distinct origin and function compared to SP, its role in inflammatory and pain processes has not yet been elucidated in such detail. In this study, we analysed the involvement of tachykinins derived from the Tac1 and Tac4 genes, as well as the NK1 receptor in chronic arthritis of the mouse. Methods Complete Freund’s Adjuvant was injected intraplantarly and into the tail of Tac1?/?, Tac4?/?, Tacr1?/? (NK1 receptor deficient) and Tac1?/?/Tac4?/? mice. Paw volume was measured by plethysmometry and mechanosensitivity using dynamic plantar aesthesiometry over a time period of 21 days. Semiquantitative histopathological scoring and ELISA measurement of IL-1β concentrations of the tibiotarsal joints were performed. Results Mechanical hyperalgesia was significantly reduced from day 11 in Tac4?/? and Tacr1?/? animals, while paw swelling was not altered in any strain. Inflammatory histopathological alterations (synovial swelling, leukocyte infiltration, cartilage destruction, bone damage) and IL-1β concentration in the joint homogenates were significantly smaller in Tac4?/? and Tac1?/?/Tac4?/? mice. Conclusions Hemokinin-1, but not substance P increases inflammation and hyperalgesia in the late phase of adjuvant-induced arthritis. While NK1 receptors mediate its antihyperalgesic actions, the involvement of another receptor in histopathological changes and IL-1β production is suggested.
Bruck decomposition for endomorphisms of quasigroups
P. T. Nagy,P. Plaumann
Mathematics , 2009,
Abstract: In the year 1944 R. H. Bruck has described a very general construction method which he called the extension of a set by a quasigroup. We use it to construct a class of examples for LF-quasigroups in which the image of the map $e(x)=x\backslash x$ is a group. More generally, we consider the variety of quasigroups which is defined by the property that the map $e$ is an endomorphism and its subvariety where the image of the map $e$ is a group. We characterize quasigroups belonging to these varieties using their Bruck decomposition with respect to the map $e$.
Utilisation of 2nd generation web technologies in master level vocational teacher training
Péter Tóth
Acta Didactica Napocensia , 2009,
Abstract: The Masters level Opportunities and Technological Innovation in Vocational Teacher Education project (project site: http://motivate.tmpk.bmf.hu/) aims to develop the use and management of virtual learning environments in the area of vocational teacher training, drawing on a well established international partnership of institutions providing both technical and educational expertise. This paper gives an overall picture of the first results and products of the collaboration. We touch upon the goals, the assessments and the learning process of using “Multimedia and e-Learning: e-learning methods and tools” module in details. The main cooperative and collaborative devices are presented in virtual learning environment. The communication during collaborative learning, the structured debate on forum and the benefits of collaborative learning in VLE are interpreted at the end of this paper.
An elementary formula for entanglement entropies of fermionic systems
Péter Lévay,Szilvia Nagy,János Pipek
Physics , 2005, DOI: 10.1103/PhysRevA.72.022302
Abstract: An elementary formula for the von Neumann and Renyi entropies describing quantum correlations in two-fermionic systems having four single particle states is presented. An interesting geometric structure of fermionic entanglement is revealed. A connection with the generalized Pauli principle is established.
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