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Search Results: 1 - 10 of 645883 matches for " Gábor A. Tóth "
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Gender Differences and Secular Trends in Height, Patterns of Growth and Maturation During Puberty
Gábor A. Tóth,Péter Molnár,Csilla Suskovics
Human Biology Review , 2012,
Abstract: The "K rmend Growth Study" (KGS) was a series of cross-sectional anthropological surveys repeated in every 10 years in a small Hungarian town for more than 50 years. In this paper the authors are reporting data concerning a special period of children`s development, the puberty and pre-puberty period. Growth patterns of children (aged 3-18 years) were examined in 1958, 1968, 1978, 1988, 1998 and 2008 and were compared. Significant gender differences and secular trends were observed in the growth pattern of 9-15 year old children. Pubertal girls were temporarily taller than their male counterparts. Physical maturation appeared in an earlier age, and lasted for a shorter duration. This paper also focuses on changes in ages at menarche. In the frame of the KGS, data of age at menarche were collected with the "status quo" method, and was analyzed using probit analysis. In the first period of the study positive secular trends were observed in K rmend but by the end of the 20th century secular changes slowed down and reached stagnation.
A generalization of Witsenhausen's zero-error rate for directed graphs
Gábor Simonyi,ágnes Tóth
Mathematics , 2014,
Abstract: We investigate a communication setup where a source output is sent through a free noisy channel first and an additional codeword is sent through a noiseless but expensive channel later. With the help of the second message the decoder should be able to decide with zero-error whether its decoding of the first message was error-free. This scenario leads to the definition of a digraph parameter that generalizes Witsenhausen's zero-error rate for directed graphs. We investigate this new parameter for some specific directed graphs and explore its relations to other digraph parameters like Sperner capacity and dichromatic number. When the original problem is modified to require zero-error decoding of the whole message then we arrive back to the Witsenhausen rate of an appropriately defined undirected graph.
Membrane-Lipid Therapy in Operation: The HSP Co-Inducer BGP-15 Activates Stress Signal Transduction Pathways by Remodeling Plasma Membrane Rafts
Imre Gombos, Tim Crul, Stefano Piotto, Burcin Güng?r, Zsolt T?r?k, Gábor Balogh, Mária Péter, J. Peter Slotte, Federica Campana, Ana-Maria Pilbat, ákos Hunya, Noémi Tóth, Zsuzsanna Literati-Nagy, László Vígh, Attila Glatz, Mario Brameshuber, Gerhard J. Schütz, Andrea Hevener, Mark A. Febbraio, Ibolya Horváth, László Vígh
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0028818
Abstract: Aging and pathophysiological conditions are linked to membrane changes which modulate membrane-controlled molecular switches, causing dysregulated heat shock protein (HSP) expression. HSP co-inducer hydroxylamines such as BGP-15 provide advanced therapeutic candidates for many diseases since they preferentially affect stressed cells and are unlikely have major side effects. In the present study in vitro molecular dynamic simulation, experiments with lipid monolayers and in vivo ultrasensitive fluorescence microscopy showed that BGP-15 alters the organization of cholesterol-rich membrane domains. Imaging of nanoscopic long-lived platforms using the raft marker glycosylphosphatidylinositol-anchored monomeric green fluorescent protein diffusing in the live Chinese hamster ovary (CHO) cell plasma membrane demonstrated that BGP-15 prevents the transient structural disintegration of rafts induced by fever-type heat stress. Moreover, BGP-15 was able to remodel cholesterol-enriched lipid platforms reminiscent of those observed earlier following non-lethal heat priming or membrane stress, and were shown to be obligate for the generation and transmission of stress signals. BGP-15 activation of HSP expression in B16-F10 mouse melanoma cells involves the Rac1 signaling cascade in accordance with the previous observation that cholesterol affects the targeting of Rac1 to membranes. Finally, in a human embryonic kidney cell line we demonstrate that BGP-15 is able to inhibit the rapid heat shock factor 1 (HSF1) acetylation monitored during the early phase of heat stress, thereby promoting a prolonged duration of HSF1 binding to heat shock elements. Taken together, our results indicate that BGP-15 has the potential to become a new class of pharmaceuticals for use in ‘membrane-lipid therapy’ to combat many various protein-misfolding diseases associated with aging.
HARM: A Numerical Scheme for General Relativistic Magnetohydrodynamics
Charles F. Gammie,Jonathan C. McKinney,Gábor Tóth
Physics , 2003, DOI: 10.1086/374594
Abstract: We describe a conservative, shock-capturing scheme for evolving the equations of general relativistic magnetohydrodynamics. The fluxes are calculated using the Harten, Lax, and van Leer scheme. A variant of constrained transport, proposed earlier by T\'oth, is used to maintain a divergence free magnetic field. Only the covariant form of the metric in a coordinate basis is required to specify the geometry. We describe code performance on a full suite of test problems in both special and general relativity. On smooth flows we show that it converges at second order. We conclude by showing some results from the evolution of a magnetized torus near a rotating black hole.
Gonzalo Garnacho,Tímea Kaszab,Márk Horváth,Gábor Géczi
Journal of Microbiology, Biotechnology and Food Sciences , 2012,
Abstract: One of the main concerns when it comes to produce foodstuff is to guarantee the consumer’s safety, preserving at the same time the original nutritive and organoleptic characteristics of the product. With the purpose of extending foodstuffs shelf life, a lot of products are thermally treated before they become commercialized. However, these thermal procedures are carried out in heating exchangers, which calls for a great deal of energy to produce the heat. Nowadays, new technologies like microwaves are being researched in order to be actual alternatives to the conventional treatments. However, the industrial application of microwave energy is still limited by the uncertainty of the energy dissipation and by the lack of information on reactions except for the thermal effects. Furthermore, the social opinion about the utilization of microwaves as a thermal treatment for foodstuff is not very favorable (Wayne and Newel, 2000; Wild, n/a). It is thought by a lot of people that the use of microwaves deteriorates the final quality of food and it consequently damages consumers’ health. This paper shows a research based on the application of microwaves to thermally treat orange juice, with the purpose of investigating the viability of the technology of microwaves on foodstuff.
No Major Differences Found between the Effects of Microwave-Based and Conventional Heat Treatment Methods on Two Different Liquid Foods
Gábor Géczi, Márk Horváth, Tímea Kaszab, Gonzalo Garnacho Alemany
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053720
Abstract: Extension of shelf life and preservation of products are both very important for the food industry. However, just as with other processes, speed and higher manufacturing performance are also beneficial. Although microwave heating is utilized in a number of industrial processes, there are many unanswered questions about its effects on foods. Here we analyze whether the effects of microwave heating with continuous flow are equivalent to those of traditional heat transfer methods. In our study, the effects of heating of liquid foods by conventional and continuous flow microwave heating were studied. Among other properties, we compared the stability of the liquid foods between the two heat treatments. Our goal was to determine whether the continuous flow microwave heating and the conventional heating methods have the same effects on the liquid foods, and, therefore, whether microwave heat treatment can effectively replace conventional heat treatments. We have compared the colour, separation phenomena of the samples treated by different methods. For milk, we also monitored the total viable cell count, for orange juice, vitamin C contents in addition to the taste of the product by sensory analysis. The majority of the results indicate that the circulating coil microwave method used here is equivalent to the conventional heating method based on thermal conduction and convection. However, some results in the analysis of the milk samples show clear differences between heat transfer methods. According to our results, the colour parameters (lightness, red-green and blue-yellow values) of the microwave treated samples differed not only from the untreated control, but also from the traditional heat treated samples. The differences are visually undetectable, however, they become evident through analytical measurement with spectrophotometer. This finding suggests that besides thermal effects, microwave-based food treatment can alter product properties in other ways as well.
The effects of isatin (indole-2, 3-dione) on pituitary adenylate cyclase-activating polypeptide-induced hyperthermia in rats
Imre Pataki, ágnes Adamik, Vivette Glover, Gábor Tóth, Gyula Telegdy
BMC Neuroscience , 2002, DOI: 10.1186/1471-2202-3-2
Abstract: One μg intracerebroventricular (icv.) injection of PACAP-38 had hyperthermic effect in male, Wistar rats, with an onset of the effect at 2 h and a decline by the 6th h after administration. Intraperitoneal (ip.) injection of different doses of isatin (25-50 mg/kg) significantly decreased the hyperthermic effect of 1 μg PACAP-38 (icv.), whereas 12.5 mg/kg isatin (ip.) had no inhibiting effect. Isatin alone did not modify the body temperature of the animals.The mechanisms that participate in the mediation of the PACAP-38-induced hyperthermia may be modified by isatin. The capability of isatin to antagonize the hyperthermia induced by all members of the natriuretic peptide family and by PACAP-38 makes it unlikely to be acting directly on receptors for natriuretic peptides or on those for PACAP in these hyperthermic processes.Pituitary adenylate cyclase-activating polypeptide (PACAP) is known as a member of a superfamily that includes vasoactive intestinal polypeptide (VIP), secretin, glucagon, gastric inhibitory polypeptide and growth hormone-releasing factor [9]. The biologically active neuropeptide exists in two amidated forms: PACAP-38, a 38-amino-acid polypeptide; and PACAP-27, a truncated form of PACAP-38 containing 27 residues [4]. Both PACAP-38 and PACAP-27 are potent in stimulating adenylate cyclase.At least two receptor classes have been reported for PACAP in mammalian tissues: type I and type II. Type I receptors are highly selective in the recognition of PACAP, and have lower affinity for VIP. Type II receptors display similar high affinity for PACAP-27, PACAP-38 and VIP [2]. Type II (VIP-PACAP) receptors interact almost exclusively with adenylate cyclase. At least two effector systems exist for type I PACAP-preferring receptors, which can stimulate both adenylate cyclase and phospholipase C. Subsequent to phospholipase C activation via the inositol phosphate cascade, a secondary Ca2+ entry elevating cytosolic [Ca2+] follows Ca2+ mobilization [9].Recent inve
Relationship of Tree Stand Heterogeneity and Forest Naturalness
BARTHA, Dénes,óDOR, Péter,HORVáTH, Tibor,TíMáR, Gábor
Acta Silvatica & Lignaria Hungarica , 2006,
Abstract: The aim of our study was to investigate if compositional (tree species richness) andstructural (vertical structure, age-structure, patterns of canopy closure) heterogeneity of the canopylayer is related to individual naturalness criteria and to overall forest naturalness at the stand scale. Thenaturalness values of the assessed criteria (tree species composition, tree stand structure, speciescomposition and structure of shrub layer and forest floor vegetation, dead wood, effects of game, sitecharacteristics) showed similar behaviour when groups of stands with different heterogeneity werecompared, regardless of the studied aspect of canopy heterogeneity. The greatest difference was foundfor criteria describing the canopy layer. Composition and structure of canopy layer, dead wood andtotal naturalness of the stand differed significantly among the stand groups showing consistentlyhigher values from homogeneous to the most heterogeneous group. Naturalness of the compositionand structure of the shrub layer is slightly but significantly higher in stands with heterogeneous canopylayer. Regarding other criteria, significant differences were found only between the homogeneous andthe most heterogeneous groups, while groups with intermediate level of heterogeneity did not differsignificantly from one extreme. However, the criterion describing effects of game got lowernaturalness values in more heterogeneous stands. Naturalness of site characteristics did not differsignificantly among the groups except for when stands were grouped based on pattern of canopyclosure. From the practical viewpoint it is shown that purposeful forestry operations affecting thecanopy layer cause changes in compositional and structural characteristics of other layers as well as inoverall stand scale forest naturalness.
The origin of the Bemaraha tsingy (Madagascar).
Márton Veress,Dénes Lóczy,Zoltán Zentai,Gábor Tóth
International Journal of Speleology , 2008,
Abstract: On Madagascar the most representative occurrences of tsingy are at Ankarana and Bemaraha. The tsingy are built up of giant grikes developed along cracks as well as karren features of much smaller size which cover the surfaces between grikes. We investigated the Bemaraha tsingy of Madagascar (surveyed profiles, measured grike directions, etc.) in order to reconstruct their development. The observations indicate that the majority of grikes of the tsingy are created from caves formed under the karst water table and subsequently opened up to the surface. The predominant processes may have been downward progressing dissolution or the collapse of cave roofs.
The role of the Hall effect in the global structure and dynamics of planetary magnetospheres: Ganymede as a case study
John C. Dorelli,Alex Glocer,Glyn Collinson,Gábor Tóth
Physics , 2015, DOI: 10.1002/2014JA020951
Abstract: We present high resolution Hall MHD simulations of Ganymede's magnetosphere demonstrating that Hall electric fields in ion-scale magnetic reconnection layers have significant global effects not captured in resistive MHD simulations. Consistent with local kinetic simulations of magnetic reconnection, our global simulations show the development of intense field-aligned currents along the magnetic separatrices. These currents extend all the way down to the moon's surface, where they may contribute to Ganymede's aurora. Within the magnetopause and magnetotail current sheets, Hall currents in the reconnection plane accelerate ions to the local Alfv\'en speed in the out-of-plane direction, producing a global system of ion drift belts that circulates Jovian magnetospheric plasma throughout Ganymede's magnetosphere. We discuss some observable consequences of these Hall-induced currents and ion drifts: the appearance of a sub-Jovian "double magnetopause" structure, an Alfv\'enic ion jet extending across the upstream magnetopause and an asymmetric pattern of magnetopause Kelvin-Helmholtz waves.
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