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The Hungarian Academy of science ) is the most important and prestigious learned society of Hungary. Its seat is at the bank of the Danube in Budapest. The main responsibilities are the cultivation of science, disseminate the results of science, the supporting of research and development and the representation of Hungarian science domestically and around the world. Wikipedia.

Asboth J.K.,Hungarian Academy of Sciences
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

Discrete-time quantum walks have been shown to simulate all known topological phases in one and two dimensions. Being periodically driven quantum systems, their topological description, however, is more complex than that of closed Hamiltonian systems. We map out the topological phases of the particle-hole symmetric one-dimensional discrete-time quantum walk. We find that there is no chiral symmetry in this system: its topology arises from the particle-hole symmetry alone. We calculate the Z 2×Z 2 topological invariant in a simple way that is consistent with a general definition for one-dimensional periodically driven quantum systems. These results allow for a transparent interpretation of the edge states on a finite lattice via the the bulk-boundary correspondence. We find that the bulk Floquet operator does not contain all the information needed for the topological invariant. As an illustration to this statement, we show that in the split-step quantum walk, the edges between two bulks with the same Floquet operator can host topologically protected edge states. © 2012 American Physical Society.

Feher A.,Hungarian Academy of Sciences
Biochimica et Biophysica Acta - Gene Regulatory Mechanisms | Year: 2015

Plants as sessile organisms have remarkable developmental plasticity ensuring heir continuous adaptation to the environment. An extreme example is somatic embryogenesis, the initiation of autonomous embryo development in somatic cells in response to exogenous and/or endogenous signals. In this review I briefly overview the various pathways that can lead to embryo development in plants in addition to the fertilization of the egg cell and highlight the importance of the interaction of stress- and hormone-regulated pathways during the induction of somatic embryogenesis. Somatic embryogenesis can be initiated in planta or in vitro, directly or indirectly, and the requirement for dedifferentiation as well as the way to achieve developmental totipotency in the various systems is discussed in light of our present knowledge. The initiation of all forms of the stress/hormone-induced in vitro as well as the genetically provoked in planta somatic embryogenesis requires extensive and coordinated genetic reprogramming that has to take place at the chromatin level, as the embryogenic program is under strong epigenetic repression in vegetative plant cells. Our present knowledge on chromatin-based mechanisms potentially involved in the somatic-to-embryogenic developmental transition is summarized emphasizing the potential role of the chromatin to integrate stress, hormonal, and developmental pathways leading to the activation of the embryogenic program. The role of stress-related chromatin reorganization in the genetic instability of in vitro cultures is also discussed. This article is part of a Special Issue entitled: Stress as a fundamental theme in cell plasticity. © 2014 Elsevier B.V.

Kiss L.,University of Szeged | Fulop F.,University of Szeged | Fulop F.,Hungarian Academy of Sciences
Chemical Reviews | Year: 2014

Alicyclic and heterocyclic β-amino acids become an expanding area in organic and medicinal chemistry. The biological characteristics of the cyclic β-amino acids as independent molecular entities, together with their usage as precursors of different heterocycles, as chiral auxiliaries in asymmetric syntheses, and as precursors of β-lactams and in foldamer chemistry. Reductive amination of β-keto esters is a suitable method also for the synthesis of functionalized racemic carbocyclic β-amino acids. Carbocyclic β-amino acids can be prepared from acyclic β-amino acid derivatives by ring-closing metathesis. An important advantage of this methodology is that it gives cyclic β-amino acids whose olefinic bond may be functionalized to yield novel substituted derivatives. Stereoselective conjugate addition of an amine nucleophile derivative to an α,β-unsaturated carboxylate is an efficient strategy for access to five- or six-membered cyclic β-amino acids.

Vertesi T.,Hungarian Academy of Sciences | Pironio S.,University of Geneva | Brunner N.,University of Bristol
Physical Review Letters | Year: 2010

We show that the detection efficiencies required for closing the detection loophole in Bell tests can be significantly lowered using quantum systems of dimension larger than two. We introduce a series of asymmetric Bell tests for which an efficiency arbitrarily close to 1/N can be tolerated using N-dimensional systems, and a symmetric Bell test for which the efficiency can be lowered down to 61.8% using four-dimensional systems. Experimental perspectives for our schemes look promising considering recent progress in atom-photon entanglement and in photon hyperentanglement. © 2010 The American Physical Society.

Gaudeul M.,French Natural History Museum | Giraud T.,University Paris - Sud | Kiss L.,Hungarian Academy of Sciences | Shykoff J.A.,University Paris - Sud
PLoS ONE | Year: 2011

Background: Ambrosia artemisiifolia is a North American native that has become one of the most problematic invasive plants in Europe and Asia. We studied its worldwide population genetic structure, using both nuclear and chloroplast microsatellite markers and an unprecedented large population sampling. Our goals were (i) to identify the sources of the invasive populations; (ii) to assess whether all invasive populations were founded by multiple introductions, as previously found in France; (iii) to examine how the introductions have affected the amount and structure of genetic variation in Europe; (iv) to document how the colonization of Europe proceeded; (v) to check whether populations exhibit significant heterozygote deficiencies, as previously observed. Principal Findings: We found evidence for multiple introductions of A. artemisiifolia, within regions but also within populations in most parts of its invasive range, leading to high levels of diversity. In Europe, introductions probably stem from two different regions of the native area: populations established in Central Europe appear to have originated from eastern North America, and Eastern European populations from more western North America. This may result from differential commercial exchanges between these geographic regions. Our results indicate that the expansion in Europe mostly occurred through long-distance dispersal, explaining the absence of isolation by distance and the weak influence of geography on the genetic structure in this area in contrast to the native range. Last, we detected significant heterozygote deficiencies in most populations. This may be explained by partial selfing, biparental inbreeding and/or a Wahlund effect and further investigation is warranted. Conclusions: This insight into the sources and pathways of common ragweed expansion may help to better understand its invasion success and provides baseline data for future studies on the evolutionary processes involved during range expansion in novel environments. © 2011 Gaudeul et al.

Peter L.,Hungarian Academy of Sciences
Journal of Solid State Electrochemistry | Year: 2013

Electrode impedance can be evaluated on the basis of the electrode reaction kinetics in many systems, even for complicated electrode reactions. However, when a surface layer is present on the electrode surface, the theoretically well-established impedance model of the electrode reaction is often completed with phenomenological equivalent circuit elements in order to achieve the number of time constants as derived from the electrode impedance spectra measured. In these cases, the meaning of the phenomenological equivalent circuit elements are often unclear, though the presence of these elements is helpful to describe the system throughout the frequency domain used for the measurement. In the present work, an attempt will be shown to separate the effect of the electronic and ionic charge transfer in a surface layer and to identify the appropriate equivalent circuits. Examples are shown from the fields of lithium-ion batteries where a solid electrolyte interface as a surface layer is present at the negative electrode and the contribution of various charge carriers may be of importance. © Springer-Verlag Berlin Heidelberg 2013.

Haas J.,Eotvos Lorand University | Gotz A.E.,TU Darmstadt | Palfy J.,Hungarian Academy of Sciences
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010

Sedimentary and organic facies of a continuous Late Triassic-Early Jurassic toe-of-slope to basin succession of the NE Transdanubian Range (N Hungary) was studied in order to reconstruct the palaeogeographical and eustatic evolution of the Cso{double-acute}vár Basin, an intraplatform basin of the NW Neotethys margin. Characteristic facies successions point to sea-level changes of different hierarchies. Cyclic patterns, inferred to result from orbital eccentricity forcing, are also reflected in the stratigraphical distribution of sedimentary organic matter. Furthermore, both palaeontological and isotope data document drastic climatic changes around the Triassic-Jurassic boundary. Detecting sea-level changes leads to a more accurate interpretation of the Late Triassic palaeogeographic setting and evolution of the Transdanubian Range's carbonate platform. Our integrated sedimentological and palynological data suggest a complex topography and dynamic sea-level history, which contradicts a previous model of broad, uniform platform setting and lack of any major drowning and emersion events during the Late Triassic. © 2010 Elsevier B.V. All rights reserved.

Karoly R.,Hungarian Academy of Sciences
PLoS computational biology | Year: 2010

Sodium channels are one of the most intensively studied drug targets. Sodium channel inhibitors (e.g., local anesthetics, anticonvulsants, antiarrhythmics and analgesics) exert their effect by stabilizing an inactivated conformation of the channels. Besides the fast-inactivated conformation, sodium channels have several distinct slow-inactivated conformational states. Stabilization of a slow-inactivated state has been proposed to be advantageous for certain therapeutic applications. Special voltage protocols are used to evoke slow inactivation of sodium channels. It is assumed that efficacy of a drug in these protocols indicates slow-inactivated state preference. We tested this assumption in simulations using four prototypical drug inhibitory mechanisms (fast or slow-inactivated state preference, with either fast or slow binding kinetics) and a kinetic model for sodium channels. Unexpectedly, we found that efficacy in these protocols (e.g., a shift of the "steady-state slow inactivation curve"), was not a reliable indicator of slow-inactivated state preference. Slowly associating fast-inactivated state-preferring drugs were indistinguishable from slow-inactivated state-preferring drugs. On the other hand, fast- and slow-inactivated state-preferring drugs tended to preferentially affect onset and recovery, respectively. The robustness of these observations was verified: i) by performing a Monte Carlo study on the effects of randomly modifying model parameters, ii) by testing the same drugs in a fundamentally different model and iii) by an analysis of the effect of systematically changing drug-specific parameters. In patch clamp electrophysiology experiments we tested five sodium channel inhibitor drugs on native sodium channels of cultured hippocampal neurons. For lidocaine, phenytoin and carbamazepine our data indicate a preference for the fast-inactivated state, while the results for fluoxetine and desipramine are inconclusive. We suggest that conclusions based on voltage protocols that are used to detect slow-inactivated state preference are unreliable and should be re-evaluated.

Atserias A.,Polytechnic University of Catalonia | Grohe M.,RWTH Aachen | Marx D.,Hungarian Academy of Sciences
SIAM Journal on Computing | Year: 2013

Relational joins are at the core of relational algebra, which in turn is the core of the standard database query language SQL. As their evaluation is expensive and very often dominated by the output size, it is an important task for database query optimizers to compute estimates on the size of joins and to find good execution plans for sequences of joins. We study these problems from a theoretical perspective, both in the worst-case model and in an average-case model where the database is chosen according to a known probability distribution. In the former case, our first key observation is that the worst-case size of a query is characterized by the fractional edge cover number of its underlying hypergraph, a combinatorial parameter previously known to provide an upper bound. We complete the picture by proving a matching lower bound and by showing that there exist queries for which the join-project plan suggested by the fractional edge cover approach may be substantially better than any join plan that does not use intermediate projections. On the other hand, we show that in the average-case model, every join-project plan can be turned into a plan containing no projections in such a way that the expected time to evaluate the plan increases only by a constant factor independent of the size of the database. Not surprisingly, the key combinatorial parameter in this context is the maximum density of the underlying hypergraph. We show how to make effective use of this parameter to eliminate the projections. © 2013 Society for Industrial and Applied Mathematics.

Baranyi T.,Hungarian Academy of Sciences
Monthly Notices of the Royal Astronomical Society | Year: 2014

The study of active region tilt angles and their variations in different time-scales plays an important role in revealing the subsurface dynamics of magnetic flux ropes and in understanding the dynamo mechanism. In order to reveal the exact characteristics of tilt angles, precise long-term tilt angle data bases are needed. However, there are only a few different data sets at present, which are difficult to be compared and cross-calibrate because of their substantial deviations. In this paper, we describe new tilt angle data bases derived from the Debrecen Photoheliographic Data (DPD) (1974-) and from the SOHO/MDI-Debrecen Data (SDD) (1996-2010) sunspot catalogues. We compare them with the traditional sunspot group tilt angle data bases of Mount Wilson Observatory (1917-85) and Kodaikanal Solar Observatory (1906-87) and we analyse the deviations. Various methods and filters are investigated which may improve the sample of data and may help in deriving better results based on combined data. As a demonstration of the enhanced quality of the improved data set a refined diagram of Joy's law is presented. © 2015 The Author.

Monostory K.,Hungarian Academy of Sciences | Dvorak Z.,Palacky University
Current Drug Metabolism | Year: 2011

Cytochrome P450 (P450) monooxygenases are capable of catalyzing metabolism of various endogenous and exogenous compounds, such as bile acids, fatty acids, retinoids, steroids, drugs and other xenobiotics. The enzymes, belonging to CYP1, CYP2 and CYP3 families are primarily involved in the metabolism of drugs and xenobiotics. P450-mediated defense mechanism protects organisms from the potentially toxic effects of xenobiotics to which they are exposed. The adaptive transcriptional induction of P450s by xenobiotics is mediated by aromatic hydrocarbon receptor of Per-ARNT-Sim family, and nuclear hormone receptors, including pregnane X receptor, constitutive androstane receptor and glucocorticoid receptor. In addition to the receptor-mediated induction, endogenous factors (developmental, sex or hormonal factors) can also modulate P450 expression. Steroid hormones are biologically active compounds, controlling many physiological processes via endocrine signaling pathways and contributing to the transcriptional regulation of drugmetabolizing P450s. Any change in P450 activities influences the rate of activation or inactivation of drugs. Exposure to xenobiotics (drugs, environmental pollutants) can exert changes in endocrine function both directly as hormone agonists/antagonists or indirectly altering the rates of hormone metabolism and consequently the circulating levels of hormones. Modulation of P450 expression by xenobiotics can affect the subsequent metabolism of not only foreign chemicals, but also steroid hormones. Perturbation in hormone metabolism leads to the imbalance in sexual and reproductive development, and in glucose, lipid and salt/water homeostasis. The purpose of this review is to highlight the interplay between drug-metabolizing P450s and steroid hormones as well as the interactions of xenosensor with steroid signaling pathways. © 2011 Bentham Science Publishers Ltd.

Winkler I.,Hungarian Academy of Sciences | Winkler I.,University of Szeged | Schroger E.,University of Leipzig
Brain and Language | Year: 2015

Communication by sounds requires that the communication channels (i.e. speech/speakers and other sound sources) had been established. This allows to separate concurrently active sound sources, to track their identity, to assess the type of message arriving from them, and to decide whether and when to react (e.g., reply to the message). We propose that these functions rely on a common generative model of the auditory environment. This model predicts upcoming sounds on the basis of representations describing temporal/sequential regularities. Predictions help to identify the continuation of the previously discovered sound sources to detect the emergence of new sources as well as changes in the behavior of the known ones. It produces auditory event representations which provide a full sensory description of the sounds, including their relation to the auditory context and the current goals of the organism. Event representations can be consciously perceived and serve as objects in various cognitive operations. © 2015 The Authors.

Adam-Vizi V.,Hungarian Academy of Sciences | Starkov A.A.,Cornell University
Journal of Alzheimer's Disease | Year: 2010

A number of recent discoveries indicate that abnormal Ca2+ signaling, oxidative stress, and mitochondrial dysfunction are involved in the neuronal damage in Alzheimer's disease. However, the literature on the interactions between these factors is controversial especially in the interpretation of the cause-effect relationship between mitochondrial damage induced by Ca2+ overload and the production of reactive oxygen species (ROS). In this review, we survey the experimental observations on the Ca2+-induced mitochondrial ROS production, explain the sources of controversy in interpreting these results, and discuss the different molecular mechanisms underlying the effect of Ca2+ on the ROS emission by brain mitochondria. © 2010 IOS Press and the authors. All rights reserved.

Knapp D.G.,Eotvos Lorand University | Pintye A.,Eotvos Lorand University | Pintye A.,Hungarian Academy of Sciences | Kovacs G.M.,Eotvos Lorand University
PLoS ONE | Year: 2012

Dark septate endophytic (DSE) fungi represent a frequent root-colonizing fungal group common in environments with strong abiotic stress, such as (semi)arid ecosystems. This work aimed to study the DSE fungi colonizing the plants of semiarid sandy grasslands with wood steppe patches on the Great Hungarian Plain. As we may assume that fungi colonizing both invasive and native species are generalists, root associated fungi (RAF) were isolated from eight native and three invasive plant species. The nrDNA sequences of the isolates were used for identification. To confirm that the fungi were endophytes an artificial inoculation system was used to test the isolates: we considered a fungus as DSE if it colonized the roots without causing a negative effect on the plant and formed microsclerotia in the roots. According to the analyses of the ITS sequence of nrDNA the 296 isolates clustered into 41 groups. We found that 14 of these 41 groups were DSE, representing approximately 60% of the isolates. The main DSE groups were generalist and showed no specificity to area or season and colonized both native and invasive species, demonstrating that exotic plants are capable of using the root endophytic fungi of the invaded areas. The DSE community of the region shows high similarity to those found in arid grasslands of North America. Taking into account a previous hypothesis about the common root colonizers of those grasslands and our results reported here, we hypothesize that plants of (semi)arid grasslands share common dominant members of the DSE fungal community on a global scale. © 2012 Knapp et al.

Mocsai A.,Semmelweis University | Mocsai A.,Hungarian Academy of Sciences | Walzog B.,Ludwig Maximilians University of Munich | Lowell C.A.,University of California at San Francisco
Cardiovascular Research | Year: 2015

Recruitment of leucocytes such as neutrophils to the extravascular space is a critical step of the inflammation process and plays a major role in the development of various diseases including several cardiovascular diseases. Neutrophils themselves play a very active role in that process by sensing their environment and responding to the extracellular cues by adhesion and de-Adhesion, cellular shape changes, chemotactic migration, and other effector functions of cell activation. Those responses are co-ordinated by a number of cell surface receptors and their complex intracellular signal transduction pathways. Here, we review neutrophil signal transduction processes critical for recruitment to the site of inflammation. The two key requirements for neutrophil recruitment are the establishment of appropriate chemoattractant gradients and the intrinsic ability of the cells to migrate along those gradients. We will first discuss signalling steps required for sensing extracellular chemoattractants such as chemokines and lipid mediators and the processes (e.g. PI3-kinase pathways) leading to the translation of extracellular chemoattractant gradients to polarized cellular responses. We will then discuss signal transduction by leucocyte adhesion receptors (e.g. tyrosine kinase pathways) which are critical for adhesion to, and migration through the vessel wall. Finally, additional neutrophil signalling pathways with an indirect effect on the neutrophil recruitment process, e.g. through modulation of the inflammatory environment, will be discussed. Mechanistic understanding of these pathways provide better understanding of the inflammation process and may point to novel therapeutic strategies for controlling excessive inflammation during infection or tissue damage. © The Author 2015. All rights reserved.

Benczur A.A.,Hungarian Academy of Sciences | Karger D.R.,Cambridge Intelligence
SIAM Journal on Computing | Year: 2015

We describe random sampling techniques for approximately solving problems that involve cuts and flows in graphs. We give a near-linear-time randomized combinatorial construction that transforms any graph on n vertices into an O(n log n)-edge graph on the same vertices whose cuts have approximately the same value as the original graph's. In this new graph, for example, we can run the Õ (m3/2)-time maximum flow algorithm of Goldberg and Rao to find an s-t minimum cut in Õ(n3/2) time. This corresponds to a (1 + ε)-times minimum s-t cut in the original graph. A related approach leads to a randomized divide-and-conquer algorithm producing an approximately maximum flow in Õ(m √n) time. Our algorithm can also be used to improve the running time of sparsest cut approximation algorithms from Õ(mn) to Õ (n2) and to accelerate several other recent cut and flow algorithms. Our algorithms are based on a general theorem analyzing the concentration of random graphs' cut values near their expectations. Our work draws only on elementary probability and graph theory. © 2015 Andras Benczúr and David R. Karger.

Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor | Perc M.,King Abdulaziz University
Journal of the Royal Society Interface | Year: 2015

The pursuit of highest payoffs in evolutionary social dilemmas is risky and sometimes inferior to conformity. Choosing the most common strategy within the interaction range is safer because it ensures that the payoff of an individual will not be much lower than average. Herding instincts and crowd behaviour in humans and social animals also compel to conformity in their own right. Motivated by these facts, we here study the impact of conformity on the evolution of cooperation in social dilemmas.We show that an appropriate fraction of conformists within the population introduces an effective surface tension around cooperative clusters and ensures smooth interfaces between different strategy domains. Payoff-driven players brake the symmetry in favour of cooperation and enable an expansion of clusters past the boundaries imposed by traditional network reciprocity. Thismechanismworks even under themost testing conditions, and it is robust against variations of the interaction network as long as degree-normalized payoffs are applied. Conformity may thus be beneficial for the resolution of social dilemmas. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Vari A.,Hungarian Academy of Sciences
Fundamental and Applied Limnology | Year: 2013

Vegetative reproduction is the most common form of propagation in aquatic macrophytes. Fragmentation and consecutive re-rooting of the fragments is one way in which new macrophyte colonies may establish. The success and frequency of this strategy depends on the species and the environment. This study tested how well six species are capable of colonising this way. Tested species are fve of the most abundant species of Lake Balaton, where macrophyte recolonisation is still to take place after improving water quality and one potentially invasive species. Fragments of standardized length were examined for survival, rooting rates and length growth during five to six week experiments under laboratory conditions. Effects of species, shoot part (apical or mid-stem part) and seasonality on rooting probability were analysed with logistic regression. Effects on life-cycle were also examined, in terms of continuation of growth and of flowering or seed-set. Species differed significantly in rooting rates and growth, but not in survival rates. Egeria densa, Myriophyllum spicatum and Potamogeton perfoliatus showed the best colonisation properties (survival rates: 95 %, 84 % and 84 %; rooting rates: 88 %, 45 % and 65 %, respectively), while Potamogeton pectinatus colonised less successfully (survival rate: 91 %, rooting rate: 38 %). The annual Najas marina was the only species which frequently reached flowering (61 %), while fragmenting further, without much rooting (rooting rate: 5 %). The non-rooting Ceratophyllum demersum was least impacted by fragmentation and continued growth best, with survival rates of 100 %. Shoot part had a significant influence on rooting rate and length growth. Apical fragments had higher rooting rates and greater length growth than stem fragments, probably due to the action of their meristematic tissue. Differences in the three repetitions of the experiment may be attributable to seasonal changes in colonisation features. It is concluded that recolonisation by fragments might be an effective way for macrophyte populations to recover in Lake Balaton. © 2013 E. Schweizerbart'sche Verlagsbuchhandlung.

Meszaros C.,Hungarian Academy of Sciences
Optimization Methods and Software | Year: 2016

The increase of computer performance continues to support the practice of large-scale optimization. Computers with multiple computing cores and vector processing capabilities are now widely available. We investigate how the recently introduced Advanced Vector Instruction (AVX) set on Intel-compatible architectures can be exploited in interior point methods for linear and nonlinear optimization. We focus on data structures and implementation techniques that utilize the new vector instructions. Our numerical experiments demonstrate that the AVX instruction set provides a significant performance boost in our implementation on large-scale problem that have significant fill-in in the sparse Cholesky factorization, achieving up to 100 gigaflops performance on a standard desktop computer on linear optimization problems for which the required Cholesky factorization is relatively dense. © 2015 Taylor & Francis.

Bertoti I.,Hungarian Academy of Sciences
Catalysis Today | Year: 2012

Nanoscale surface modification of a number of metal oxides was performed by bombarding them with N 2 + of 1-5 keV energy. Compositional and chemical state alterations, the valence state of the metals, the chemical states of the built-in nitrogen, were monitored by quantitative XPS analysis, performed in situ, without exposing the modified surface to the environment. It is demonstrated that N 2 + bombardment created oxygen deficient surface with significantly lower oxygen to metal (O/Me) ratio than that produced by the purely ballistic effect of Ar + bombardment of similar energy and ion-dose. This "excess" oxygen-loss, detected at N 2 + bombardment, is substituted by an equal number of nitrogen atoms in the lattice of the reduced oxide. The implanted nitrogen established chemical bonds predominantly with the metal as manifested by its XPS chemical shift, creating by this a metal oxinitride on the surface of the parent oxide. The observed alterations are interpreted in the light of ion-solid interaction, involving the thermodynamic stability and the valence state of the oxides. A mechanism is proposed to elucidate the observed, thermodynamically unfavoured oxide-to-nitride transformation. The presented results offer a straightforward way for altering the electronic structure of the surface of oxides which may be beneficial for different, especially for photocatalytic applications of the modified oxides. © 2011 Elsevier B.V. All rights reserved.

Stefanics G.,ETH Zurich | Stefanics G.,University of Zurich | Kremlacek J.,Charles University | Czigler I.,Hungarian Academy of Sciences
Frontiers in Human Neuroscience | Year: 2014

An increasing number of studies investigate the visual mismatch negativity (vMMN) or use the vMMN as a tool to probe various aspects of human cognition. This paper reviews the theoretical underpinnings of vMMN in the light of methodological considerations and provides recommendations for measuring and interpreting the vMMN. The following key issues are discussed from the experimentalist's point of view in a predictive coding framework: (1) experimental protocols and procedures to control “refractoriness” effects; (2) methods to control attention; (3) vMMN and veridical perception. © 2014 Stefanics, Kremláček and Czigler.

Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor | Perc M.,King Abdulaziz University
New Journal of Physics | Year: 2015

If rock beats scissors and scissors beat paper, one might assume that rock beats paper too. But this is not the case for intransitive relationships that make up the famous rock-paper-scissors game. However, the sole presence of paper might prevent rock from beating scissors, simply because paper beats rock. This is the blueprint for the rock-paper-scissors game with protection spillovers, which has recently been introduced as a new paradigm for biodiversity in well-mixed microbial populations. Here we study the game in structured populations, demonstrating that protection spillovers give rise to spatial patterns that are impossible to observe in the classical rock-paper-scissors game. We show that the spatiotemporal dynamics of the system is determined by the density of stable vortices, which may ultimately transform to frozen states, to propagating waves, or to target waves with reversed propagation direction, depending further on the degree and type of randomness in the interactions among the species. If vortices are rare, the fixation to waves and complex oscillatory solutions is likelier. Moreover, annealed randomness in interactions favors the emergence of target waves, while quenched randomness favors collective synchronization. Our results demonstrate that protection spillovers may fundamentally change the dynamics of cyclic dominance in structured populations, and they outline the possibility of programming pattern formation in microbial populations. © 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Kereszturi A.,Hungarian Academy of Sciences
Planetary and Space Science | Year: 2012

Bedrock outcrops were analyzed inside craters on Mars at Meridiani Planum with correlating HiRISE based remote and the Opportunity rover based in-situ images. The aim was to get information on how outcrops could be identified from above in order to help targeting and interpretation of shallow subsurface sampling attempts on Mars by rovers like the planned ExoMars. During the analysis, outcrop indicators, such as albedo differences, rectangular blocks, protruding layers and steep walls were identified inside impact craters. Using shadow length measurements and analyzing density distribution of blocks, nearly vertical walls could also be identified even in images acquired under vertical viewing condition. There is a size dependent tendency in the occurrence of outcrops inside caters. Impact craters with diameters of 5-10 m may indicate a subsurface lithology that differs from that visible on the surface, while craters with diameter above 50 m may indicate subsurface layering. Many useful large outcrops are present inside craters above diameter of 100 m and are possible targets for detailed in-situ analysis. The depth that can be reached by the drill of ExoMars is exhumed by outcrops inside craters above 50-80 m diameter. The values presented here are valid only for Terra Meridiani since craters would excavate different subsurface layers in areas with different subsurface lithologies. Although future missions with the aim of subsurface sampling will probably land not at Terra Meridiani, but these terrains could be sedimentary plains too, so the experiences outlined in this work may still be useful there. The identified outcrops may help in the planning of in-situ work and also in the interpretation of results from drill activity. © 2012 Elsevier Ltd. All rights reserved.

Egri P.,Hungarian Academy of Sciences
Autonomous Agents and Multi-Agent Systems | Year: 2015

This paper presents a multiple newsvendor-type purchasing problem where demand forecasts of a number of individual consumer agents can be generated at a price. Firstly, we derive the optimal solution for the model. Next, an information elicitation mechanism is presented that results in the optimal solution despite the autonomous, self-interested participants and the information asymmetry in between consumers and the supplier. Specifically, the incentive compatibility, efficiency, individual rationality and budget balance properties of the mechanism are proved and also illustrated by several numerical experiments. © 2015 The Author(s)

Glanzel W.,Catholic University of Leuven | Glanzel W.,Hungarian Academy of Sciences
Scientometrics | Year: 2015

This paper attempts to sketch the interrelation between information retrieval and scientometrics pointing at possible synergy effects provided by some recently developed bibliometric methods in the context of subject delineation and clustering. Examples of specific search strategies based on both traditional retrieval techniques and bibliometric methods are used to illustrate this approach. Special attention is paid to hybrid techniques and the use of ‘core documents’. The latter ones are defined merely on the basis of bibliometric similarities, but have by definition properties that make ‘core documents’ also interesting and attractive for information retrieval. © 2014, Akadémiai Kiadó, Budapest, Hungary.

Sipos G.,Hungarian Academy of Sciences
Future Generation Computer Systems | Year: 2012

Collaborative development environments allow a group of users to view and edit a shared item from geographically dispersed sites. Consistency maintenance in the face of concurrent accesses to shared entities is one of the core issues in the design of these systems. The paper introduces a lock based solution and three different algorithms that enable controlled, concurrent access to workflows for multiple application developers. Collaborative development of workflow applications promises better outcome in shorter time. The described method ensures that collaborators cannot break the consistency criteria of workflows by adding cycles or invalid edges to the graphs. A formal analysis of the three graph locking algorithms is also provided, focusing on the number of users who are allowed to edit a single workflow simultaneously. Based on the findings, a more powerful fourth graph locking algorithm is defined. © 2011 Elsevier B.V. All rights reserved.

Galambos P.,Hungarian Academy of Sciences
Acta Polytechnica Hungarica | Year: 2012

In telemanipulation and 3D virtual interactions it is important to transmit force sensation from the remote or virtual environment to the operator. Due to the weak points (control issues, robustness, cost) of real force feedback devices, methods where force is rendered on non-native sensory channels have grounds. In this paper, a survey of the related literature is presented and the concept of sensor-bridging type cognitive info communications based force reflecting schemes is discussed. A complete experimental infrastructure with hardware and software components is built providing a background for the investigation of the proposed methods from practical usability aspects. This environment is utilized in a pilot experiment with human participants providing substantial observations on the usability of sensor-bridging type vibrotactile force feedback methods. The test confirms that vibrotactile glove equipped with shaftless vibration motors can be successfully applied as tactile/haptic feedback device in immersive virtual reality applications.

Mocsai A.,Semmelweis University | Mocsai A.,Hungarian Academy of Sciences | Kovacs L.,University of Szeged | Gergely P.,Novartis
BMC Medicine | Year: 2014

Background: Until late in the 20th century, the therapy of rheumatic diseases relied on the use of drugs that had been developed through empirical approaches without detailed understanding of the molecular mechanisms involved. That approach changed with the introduction of biologic therapeutics at the end of the 20th century and by the recent development of small-molecule inhibitors of intracellular signal transduction pathways. Here we compare and discuss the advantages and disadvantages of those two groups of targeted anti-inflammatory therapeutics.Discussion: TNF-blocking biologic agents were introduced into the therapy of rheumatoid arthritis and other autoimmune and inflammatory diseases in the late 1990s. Further biologic agents targeting cytokine networks or specific lymphocyte subsets have since been added to the armamentarium of anti-rheumatic therapy. During the last few years, another wave of novel discoveries led to the development of a new class of small molecule anti-inflammatory compounds targeting intracellular signal transduction molecules, such as tyrosine kinases. In all those cases, the specific targets of the drugs are well defined and significant knowledge about their role in the disease pathomechanism is available, qualifying them for being targeted therapeutics for inflammatory rheumatic diseases. While both groups of targeted therapeutics offer significant clinical benefit, they clearly differ in several aspects, such as the localization of their targets, their route of administration and target specificity, as well as technical details such as manufacturing procedures and cost basis. In this debate paper, we compare the advantages and disadvantages of the two different approaches, aiming to shed light on the possible future of targeted therapies.Summary: Biologic therapeutics and small-molecule inhibitors both have significant advantages and disadvantages in the therapy of rheumatic diseases. The future of targeted therapies is one of the most exciting questions of current rheumatology research and therapy. © 2014 Mócsai et al.; licensee BioMed Central Ltd.

Takacs P.,Hungarian Academy of Sciences
Annales de Limnologie | Year: 2012

The aim of this study was to examine morphometric differentiation of gudgeon (Romanogobio and Gobio) species inhabiting the Carpathian Basin, Hungary, with special regard to two recently described species classified into the Gobio genus. For statistical analyses, 23 morphometric and 8 meristic characters were measured on each of the 733 preserved specimens originating from museum collections. The analyses of the standardized morphometric traits revealed low intraspecific variability in all studied species, but varying degrees of interspecific differences. The strongest morphometric differentiation was found in Romanogobio uranoscopus (Agassiz, 1828), which can be characterized by the most special environmental needs. The two allopatric Gobio species showed the weakest morphometric difference. The meristic characters showed high variability in the Romanogobio spp., but did not show significant differences in the two Gobio species. The results show that the morphometric and meristic similarity of the studied Gobio species is definitely high, which preclude reliable identification based on phenotypic characters if only some specimens are available. It seems that the most usable discriminating feature for these species is the localization of the collection site. © 2012 EDP Sciences.

Munoz M.A.,University of Granada | Juhasz R.,Hungarian Academy of Sciences | Castellano C.,University of Rome La Sapienza | Odor G.,Research Institute for Technical Physics and Materials Science
Physical Review Letters | Year: 2010

Quenched disorder is known to play a relevant role in dynamical processes and phase transitions. Its effects on the dynamics of complex networks have hardly been studied. Aimed at filling this gap, we analyze the contact process, i.e., the simplest propagation model, with quenched disorder on complex networks. We find Griffiths phases and other rare-region effects, leading rather generically to anomalously slow (algebraic, logarithmic,...) relaxation, on Erdos-Rényi networks. Similar effects are predicted to exist for other topologies with a finite percolation threshold. More surprisingly, we find that Griffiths phases can also emerge in the absence of quenched disorder, as a consequence of topological heterogeneity in networks with finite topological dimension. These results have a broad spectrum of implications for propagation phenomena and other dynamical processes on networks. © 2010 The American Physical Society.

Light within the littoral zone affects the productivity and interaction between periphyton and its macrophyte substrate. The effect of periphyton on macrophyte photosynthesis, seasonal variation and vertical distribution of periphyton on artificial substrates (plastic strips), and the effect of periphyton on the light environment was studied in Lake Balaton. Data showed that an average of 4.1 ± 0.4 mg (dry weight) cm-2 of periphyton had accumulated on the plastic strips after 8.8 ± 0.4 days. This biomass corresponded to 294 ± 30 μg m-2 chl-a of epiphytic algae and blocked 92.3 ± 0.8 % of the depth specific radiation. Seasonal variation and specific vertical distribution of periphyton were observed. The most active time of periphyton accumulation corresponded to spring up until mid-June. Later in the year, the amount of periphyton significantly decreased. The optimal conditions for periphyton accumulation were at 30-40 cm depth. Most of the light reaching the adaxial leaf surface was attenuated by periphyton, decreasing the production of Potamogeton perfoliatus by 60-80 %. This increased the importance of backscattered light that corresponded to 10-15 % of the macrophyte production. A smaller part of the periphyton consisted of precipitated inorganic material, while epiphytic algae, making up the majority of the periphyton, were connected to both benthic (dominantly benthic penales) and pelagic (very close seasonal dynamics of pelagic and epiphytic biomass) algae. Periphyton affects macrophyte production especially in spring and in the upper water layers even in a mesotrophic water body. This increases the importance of the light absorbed through the abaxial side of the leaf and confirm the role of periphyton in transition from clear to turbid water states. © 2013 Springer Basel.

Ojvari G.,Hungarian Academy of Sciences | Varga A.,University of Pecs | Raucsik B.,University of Pecs | Kovacs J.,University of Pecs
Quaternary International | Year: 2014

The Paks loess-paleosol sequence is one of the most important terrestrial records of Middle and Late Pleistocene environmental changes in East Central Europe, spanning the last ca. 0.8. Ma. While geochemical proxies demonstrate a general decreasing chemical weathering trend over the last 0.8. Ma in the Carpathian Basin, mineralogy and derived indices reflect intensifying physical erosion. In theory, the observed chemical weathering trend can be accounted for both by enhanced input of relatively unweathered material and by climate deterioration during the Quaternary, as the proxies such as CIA are not capable of distinguishing between pre- and post-depositional weathering. Enhanced physical erosion of the source areas, driven by tectonism, and resulting increased sedimentation of fresh mineral dust at the depositional site are demonstrated by increasing dolomite, illite and chlorite contents and sme/ill, sme/(ill. +. chl) ratios from older to younger sediments in the profile, together with increasing thickness of loess layers towards the youngest part of the sequence. At the same time, constant smectite contents (30-40%) in paleosols appear to disprove progressive aridization of interglacials through time and suggest that the duration of pedogenesis played an important role in determining soil types. Further, the increasing proportion of inherited phyllosilicates (illite and chlorite) would, in theory, raise the possibility that the decreasing values of chemical weathering indices are just artifacts of enhanced physical erosion and resulting increased dust deposition by a dilution effect. The above findings highlight the fact that the general view on chemical weathering is oversimplistic, as its 'equation' includes two basic variables, tectonism and time beyond climate and the interplay of these equally important factors will eventually determine its final value. To get a better grasp of these processes needs further data (more age control in loess profiles, data on uplift in and around sedimentary basins) and more sophisticated proxies, as the mineralogical data presented here can be considered only semiquantitative.Regarding the provenance of sediments in the Paks profile, geochemical data demonstrate that felsic rocks dominated the source areas and there have been only very little variations in provenance over the last ca. 0.8. Ma. Significant contributions from mafic/ultramafic rocks to the sediments can be ruled out as revealed by lower abundances of ferromagnesian trace elements. The appearance of amphiboles and high dolomite contents suggest that loess material was at least partly sourced from local rocks and geochemical data reveal a genetic link between floodplain sediments and loess deposits. © 2012 Elsevier Ltd and INQUA.

Kontschan J.,Hungarian Academy of Sciences | Stary J.,Academy of Sciences of the Czech Republic
Zootaxa | Year: 2011

Sixteen species of Uropodina were found in samples of soil mites from Vietnam, in the Institute of Soil Biology of the Biology Centre AS CR (Èesk Budìjovice, Czech Republic) and the Soil Zoology Collections of the Hungarian Natural History Museum (Budapest, Hungary). Five of them are known species - Angulobaloghia vietnamensis (Kontschán, 2008), Metagynella vietnamensis Hiramatsu, 1981, Uroobovella similitakensis Hirschmann, 1981, Uroobovella topali Hirschmann, 1981, and Uropoda hirschmanni Hiramatsu, 1977. Eleven species are described as new - Trachytes vietnamensis sp. nov., Dinychus serratus sp. nov., Trichouropoda aspera sp. nov., Uroobovella oviformis sp. nov., Uroobovella multisetosa sp. nov., Paradinychus pilosus sp. nov., Phymatodiscus kuni sp. nov., Uropoda setata sp. nov., Uropoda lichenicola sp. nov., Angulobaloghia scrobia sp. nov. and Depressorotunda (Depressorotunda) alveolata sp. nov. The genus Paradinychus is resurrected and three species are moved into this genus, as P. sumatrensis (Vitzthum, 1921) comb. nov. and P. fistulata (Hiramatsu, 1982) comb. nov. Keys to the species of the genus Paradinychus, to the Asian species of Trachytes and to the Uropoda spiculata species group are given. Copyright © 2011.

Gereben O.,Hungarian Academy of Sciences | Petkov V.,Central Michigan University
Journal of Physics Condensed Matter | Year: 2013

A new method to fit experimental diffraction data with non-periodic structure models for spherical particles was implemented in the reverse Monte Carlo simulation code. The method was tested on x-ray diffraction data for ruthenium (Ru) nanoparticles approximately 5.6 nm in diameter. It was found that the atomic ordering in the ruthenium nanoparticles is quite distorted, barely resembling the hexagonal structure of bulk Ru. The average coordination number for the bulk decreased from 12 to 11.25. A similar lack of structural order has been observed with other nanoparticles (e.g. Petkov et al 2008 J. Phys. Chem. C 112 8907-11) indicating that atomic disorder is a widespread feature of nanoparticles less than 10 nm in diameter. © 2013 IOP Publishing Ltd.

Baranyi P.,Hungarian Academy of Sciences
IEEE Transactions on Fuzzy Systems | Year: 2014

This paper integrates various ideas about the tensor product (TP) model transformation into one conceptual framework and formulates it in terms of the Takagi-Sugeno (T-S) fuzzy model manipulation and control design framework. Several new extensions of the TP model transformation are proposed, such as the quasi and 'full,' compact and rank-reduced higher order singular-value- decomposition-based canonical form of T-S fuzzy models, and the bilinear-, multi, pseudo-, convex-, partial TP model transformations. All of these extensions together form the generalized TP model transformation, which provides an effective tool to freely and readily manipulate the antecedent sets and rules of T-S fuzzy models and also provides main fuzzy rule component analysis, as well as a means for complexity and accuracy tradeoffs. It is demonstrated in this paper that the proposed manipulation forms a new, effective, and necessary optimization step of T-S fuzzy or polytopic models and linear-matrix-inequality- based control design, and can also decrease conservativeness. Identification techniques are typically constructed according to the available data and measurement set, as well as the type of system to be identified. As a result, they may not always provide good representations for control design frameworks. This paper demonstrates that the proposed TP model transformation is unique in that it bridges between various soft-computing-based identification techniques and T-S fuzzy model-based approaches. Finally, this paper proposes the multi-TP model transformation, which is a tractable and nonheuristic framework to verify the stability of the result of fuzzy or various soft-computing-based control designs. The multi-TP model transformation could provide an answer to the frequently emerging criticisms regarding the lack of mathematical stability verification techniques in the soft-computing-based control design. Control examples are provided in this paper. © 1993-2012 IEEE.

Menyhard M.,Hungarian Academy of Sciences
Journal of Physics D: Applied Physics | Year: 2013

The various studies of nanoparticles are of great importance because of the wide application of nanotechnology. The shape and structure of the nanoparticles can be determined by transmission electron microscopy (TEM) and their chemistry by electron energy loss spectroscopy. TEM sample preparation is an expensive and difficult procedure, however. Surface sensitive, analytical techniques, such as Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) are well applicable to detect the atoms that make up the nanoparticles, but cannot determine whether particle formation occurred. On the other hand, reflection electron energy loss spectroscopy (REELS) probes the electronic structures of atoms, which are strongly different for the atoms being in solution or in precipitated form. If the particle size is in the nm range, plasmon resonance can be excited in it, which appears as a loss feature in REELS spectrum. Thus, by measuring AES (XPS) spectra parallel with those of REELS, besides the atomic concentrations the presence of the nanoparticles can also be identified. As an example, the appearance of nanoparticles during ion beam induced mixing of C/Si layer will be shown. © 2013 IOP Publishing Ltd.

Aouacheria A.,Ecole Normale Superieure de Lyon | Combet C.,University of Lyon | Tompa P.,Hungarian Academy of Sciences | Tompa P.,Vrije Universiteit Brussel | Hardwick J.M.,Johns Hopkins University
Trends in Biochemical Sciences | Year: 2015

B cell lymphoma-2 (BCL-2)-related proteins control programmed cell death through a complex network of protein-protein interactions mediated by BCL-2 homology 3 (BH3) domains. Given their roles as dynamic linchpins, the discovery of novel BH3-containing proteins has attracted considerable attention. However, without a clearly defined BH3 signature sequence the BCL-2 family has expanded to include a nebulous group of nonhomologous BH3-only proteins, now justified by an intriguing twist. We present evidence that BH3s from both ordered and disordered proteins represent a new class of short linear motifs (SLiMs) or molecular recognition features (MoRFs) and are diverse in their evolutionary histories. The implied corollaries are that BH3s have a broad phylogenetic distribution and could potentially bind to non-BCL-2-like structural domains with distinct functions. BCL-2 family interactions are mediated by evolutionarily diverse BH3 motifs to regulate apoptosis. Given their key roles, BH3 mimetics are in clinical trials as cancer therapies.The discovery of novel BH3-only proteins represents a major endeavor in the cell death field. As a result, BH3 motifs are reportedly present in a nebulous conglomerate of different proteins, both structured and intrinsically disordered.There is no rigorous definition of a BH3 motif. Currently available BH3 signatures are diverse and elusive for predicting new functional BH3-containing proteins.Redefining the BH3 motif as a new type of short linear motif (SLiM) or molecular recognition feature (MoRF) reconciles many puzzling features of this motif and opens up new avenues for research. © 2015 Elsevier Ltd.

Kontschan J.,Hungarian Academy of Sciences
Zootaxa | Year: 2012

Six new species of Uropodina are described and illustrated on the basis of specimens collected in India. The new species are Uroseius (Apionseius) durjadhanai sp. nov., Trichouropoda arjunai sp. nov., Uropoda bengalica sp. nov., Uropoda lawrencei sp. nov., Uropoda karnai sp. nov. and Discourella pandui sp. nov. Copyright © 2012 · Magnolia Press.

Ujvari Z.,Hungarian Academy of Sciences
Journal of Natural History | Year: 2013

During the study of rich material collected in the USA, six Zerconidae species were found which seem to belong to the genus Amerozercon Halašková, 1969. Four of them, Amerozercon annularis sp. nov., Amerozercon auricularis sp. nov., Amerozercon halaskovae sp. nov. and Amerozercon penicillatus sp. nov. proved to be new to science. The unknown female of the type species of the genus, Amerozercon suspiciosus Halašková, 1969, is described. Amerozercon minimus (Sellnick, 1958) is redescribed and transferred from the genus Zercon C. L. Koch, 1836 to Amerozercon. Some remarks on the problems of the present Zerconidae systematics are discussed. © 2013 Copyright Taylor and Francis Group, LLC.

Podani J.,Hungarian Academy of Sciences | Schmera D.,University of Basel | Schmera D.,Balaton Limnological Research Institute
Ecography | Year: 2012

This paper deals with nestedness measures that are based on pairwise comparisons of sites, evaluates their performance and suggests improvements and generalizations. There are several conceptual and technical criteria to judge their ecological applicability. It is of primary concern whether the measures 1) have a clear mathematical definition, 2) are influenced by the ordering of the data matrix, 3) incorporate similarity alone or similarity together with a dissimilarity component, 4) consider site pairs with identical species number negatively or positively, 5) show sensitivity to small changes in the data, and 6) are not vulnerable to type I and type II error rates. We performed a detailed comparison of the nestedness metric based on overlap and decreasing fill (NODF), the percentage relativized nestedness and the percentage relativized strict nestedness functions (PRN and PRSN, respectively), based on analytical results as well as on artificial and actual examples. We show that NODF is in fact the average Simpson similarity of sites with different species totals, and that its value depends on how the matrix is actually ordered. NODF is modified to always produce the maximum possible result (NODF max), independently of the order of columns and rows. Being based on similarities, NODF and NODF max overemphasize the overlap component of nestedness and underrate richness difference which is also an important constituent of nested pattern in meta-community data. This latter feature is reflected adequately by PRN and PRSN. However, PRSN is similar to NODF and NODF max in sharing the disadvantages that 1) complete agreement and segregation in species composition are not distinguished, 2) a random matrix can have a higher value than truly nested patterns, and 3) they are ill-conditioned statistically. These problems are rooted mostly in that site pairs with tied totals affect the result negatively. We emphasize that PRN is free from these difficulties. PRN, PRSN, and NODF max, together with mean Simpson similarity exhibit highly similar statistical performance: they are resistant to type I and type II errors for the less constrained null models, although there are subtle differences depending on matrix fill and algorithm of randomization. The most constrained null model, with all marginal totals fixed, makes all statistics more sensitive to type I errors, although vulnerability depends greatly on matrix fill. © 2012 The Authors.

This paper presents a graph theoretical overview of tree diagrams applied extensively in systematic biology. Simple evolutionary models involving three speciation processes (splitting, budding and anagenesis) are used for evaluating the ability of different rooted trees to demonstrate temporal and ancestor-descendant relationships within or among species. On this basis, they are classified into four types: (i) diachronous trees depict evolutionary history faithfully because the order of nodes along any path agrees with the temporal sequence of respective populations or species, (ii) achronous trees show ancestor-descendant relationships for species or higher taxa such that the time aspect is disregarded, (iii) synchronous trees attempt to reveal evolutionary pathways and/or distributional patterns of apomorphic characters for organisms living at the same point of time, and (iv) asynchronous trees may do the same regardless the time of origin (e.g. when extant and extinct species are evaluated together). Trees of the last two types are cladograms, the synchronous ones emphasizing predominantly-but not exclusively-the evolutionary process within a group, while asynchronous cladograms are usually focused on pattern and infrequently on process. Historical comments and the examples demonstrate that each of these tree types is useful on its own right in evolutionary biology and systematics. In practice, separation among them is not sharp, and their features are often combined into eclectic tree forms whose interpretation is not entirely free from problems. © The Willi Hennig Society 2012.

Takarics B.,Hungarian Academy of Sciences
IEEE 10th Jubilee International Symposium on Applied Machine Intelligence and Informatics, SAMI 2012 - Proceedings | Year: 2012

The main contribution of this paper is a new sliding mode design methodology for nonlinear systems, which utilizes the Parallel Distributed Compensation based multi-objective LMI control design for Takagi-Sugeno type polytopic representations of qLPV models. It is partially extension and combination of the classical optimal manifold design for linear (or linearized) system and sector sliding mode control. This new approach enables a systematic design and decomposition of optimal sliding sector by the High Order Singular Value Decomposition based canonical description of a wide class of nonlinear systems. This brings the advantages of the LMI based control design to the field of sliding mode control. The effectiveness of the methodology is validated by simulation results. © 2012 IEEE.

Brunner N.,University of Geneva | Brunner N.,University of Bristol | Navascues M.,University of Bristol | Vertesi T.,Hungarian Academy of Sciences
Physical Review Letters | Year: 2013

Dimension witnesses allow one to test the dimension of an unknown physical system in a device-independent manner, that is, without placing assumptions about the functioning of the devices used in the experiment. Here we present simple and general dimension witnesses for quantum systems of arbitrary Hilbert space dimension. Our approach is deeply connected to the problem of quantum state discrimination, hence establishing a strong link between these two research topics. Finally, our dimension witnesses can distinguish between classical and quantum systems of the same dimension, making them potentially useful for quantum information processing. © 2013 American Physical Society.

Roller M.,University of Zagreb | Lucic V.,University of Zagreb | Nagy I.,Hungarian Academy of Sciences | Perica T.,University of Cambridge | And 2 more authors.
Nucleic Acids Research | Year: 2013

Microbial communities represent the largest portion of the Earth's biomass. Metagenomics projects use high-throughput sequencing to survey these communities and shed light on genetic capabilities that enable microbes to inhabit every corner of the biosphere. Metagenome studies are generally based on (i) classifying and ranking functions of identified genes; and (ii) estimating the phyletic distribution of constituent microbial species. To understand microbial communities at the systems level, it is necessary to extend these studies beyond the species' boundaries and capture higher levels of metabolic complexity. We evaluated 11 metagenome samples and demonstrated that microbes inhabiting the same ecological niche share common preferences for synonymous codons, regardless of their phylogeny. By exploring concepts of translational optimization through codon usage adaptation, we demonstrated that community-wide bias in codon usage can be used as a prediction tool for lifestyle-specific genes across the entire microbial community, effectively considering microbial communities as meta-genomes. These findings set up a 'functional metagenomics' platform for the identification of genes relevant for adaptations of entire microbial communities to environments. Our results provide valuable arguments in defining the concept of microbial species through the context of their interactions within the community. © 2013 The Author(s) 2013.

Liang Y.-C.,University of Geneva | Liang Y.-C.,University of Sydney | Vertesi T.,Hungarian Academy of Sciences | Brunner N.,University of Bristol
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

Detection and quantification of entanglement in quantum resources are two key steps in the implementation of various quantum-information processing tasks. Here, we show that Bell-type inequalities are not only useful in verifying the presence of entanglement but can also be used to bound the entanglement of the underlying physical system. Our main tool consists of a family of Clauser-Horne-like Bell inequalities that cannot be violated maximally by any finite-dimensional maximally entangled state. Using these inequalities, we demonstrate the explicit construction of both lower and upper bounds on the concurrence for two-qubit states. The fact that these bounds arise from Bell-type inequalities also allows them to be obtained in a semi-device- independent manner, that is, with assumption of the dimension of the Hilbert space but without resorting to any knowledge of the actual measurements being performed on the individual subsystems. © 2011 American Physical Society.

Demeter G.,Hungarian Academy of Sciences
Computer Physics Communications | Year: 2013

We solve the Maxwell-Bloch equations of resonant nonlinear optics using GPUs and compare the computation times with traditional single- and multithreaded programs. A detailed benchmarking of programs as a function of various parameters shows how the massive parallelism built into GPUs becomes more and more advantageous as the physical problem becomes more and more demanding. For the case of multimode light propagating through an inhomogeneously broadened medium of many-level quantum systems, the program executing on GPUs can be over 20 times faster than that executing on all cores of a modern CPU. The methods presented can be applied in a wide area of atomic physics where the time evolution of atomic ensembles is to be computed. © 2012 Elsevier B.V. All rights reserved.

Lagaly G.,University of Kiel | Dekany I.,Hungarian Academy of Sciences
Developments in Clay Science | Year: 2013

The knowledge of the properties of colloidal dispersions is fundamental for designing and optimizing the usage of clays and clay minerals. The colloidal behaviour of these dispersions is very complex due to the anisometric (and often irregular) particle shape, the anisometric and pH-dependent charge distribution, the variable particle dimensions as a consequence of swelling, delamination and exfoliation, and the ion-exchange properties. Therefore, this chapter gives information on the structure, charge distribution, structure of the hydrates, diffuse ionic layer, and the interactions between the colloidal clay mineral particles (electrostatic, van der Waals, ion correlation, steric stabilization). A large section refers to the coagulation of clay mineral dispersions by salts, the influence of organic compounds, and the destabilization (flocculation by bridging or charge neutralization) or stabilization by polymers (by recharging or steric stabilization). In a further section is described the aggregation of clay mineral particles leading to different types of sediments (decisively determining sealing, plastering, stirring, filtration processes, plasticity) or resulting in gel formation, often with thixotropic properties. Also mentioned is the preparation of colloidal metal (hydr)oxides and sulphides within the network of clay mineral particles or even between the clay mineral layers. © 2013 Elsevier Ltd.

Erdos G.,Hungarian Academy of Sciences | Balogh A.,Imperial College London
Astrophysical Journal | Year: 2012

The radial component of the heliospheric magnetic field vector is used to estimate the open magnetic flux density of the Sun. This parameter has been calculated using observations from the Ulysses mission that covered heliolatitudes from 80°S to 80°N, from 1990 to 2009 and distances from 1 to 5.4AU, the Advanced Composition Explorer mission at 1AU from 1997 to 2010, the OMNI interplanetary database from 1971, and the Helios 1 and 2 missions that covered the distance range from 0.3 to 1AU. The flux density was found to be much affected by fluctuations in the magnetic field which make its calculated value dependent on heliospheric location, type of solar wind (fast or slow), and the level of solar activity. However, fluctuations are distributed symmetrically perpendicular to the average Parker direction. Therefore, distributions of the field vector in the two-dimensional plane defined by the radial and azimuthal directions in heliospheric coordinates provide a way to reduce the effects of the fluctuations on the measurement of the flux density. This leads to a better defined flux density parameter; the distributions modified by removing the effects of fluctuations then allow a clearer assessment of the dependence of the flux density on heliospheric location, solar wind type, and solar activity. This assessment indicates that the flux density normalized to 1AU is independent of location and solar wind type (fast or slow). However, there is a residual dependence on solar activity which can be studied using the modified flux density measurements. © 2012. The American Astronomical Society. All rights reserved..

Rauscher T.,University of Hertfordshire | Rauscher T.,Hungarian Academy of Sciences | Rauscher T.,University of Basel
Physical Review Letters | Year: 2013

The Sm146/Sm144 ratio in the early solar system has been constrained by Nd/Sm isotope ratios in meteoritic material. Predictions of Sm146 and Sm144 production in the γ process in massive stars are at odds with these constraints, and this is partly due to deficiencies in the prediction of the reaction rates involved. The production ratio depends almost exclusively on the (γ,n)/(γ,α) branching at Gd148. A measurement of Sm144(α,γ)Gd148 at low energy had discovered considerable discrepancies between cross-section predictions and the data. Although this reaction cross section mainly depends on the optical α+nucleus potential, no global optical potential has yet been found that can consistently describe the results of this and similar α-induced reactions at the low energies encountered in astrophysical environments. The untypically large deviation in Sm144(α,γ) and the unusual energy dependence can be explained, however, by low-energy Coulomb excitation, which is competing with compound nucleus formation at very low energies. Considering this additional reaction channel, the cross sections can be described with the usual optical potential variations, compatible with findings for (n, α) reactions in this mass range. Low-energy (α, γ) and (α, n) data on other nuclei can also be consistently explained in this way. Since Coulomb excitation does not affect α emission, the Gd148(γ,α) rate is much higher than previously assumed. This leads to very small Sm146/Sm144 stellar production ratios, in even more pronounced conflict with the meteorite data. © 2013 American Physical Society.

Donko Z.,Hungarian Academy of Sciences
Physics of Plasmas | Year: 2014

Coulomb collisions, at appreciable ratios (η) of the electron to the neutral particle density, influence significantly the electron kinetics in particle swarms and in plasmas of gas discharges. This paper introduces a combination of Molecular Dynamics and Monte Carlo simulation techniques, to provide a novel, approximation-free, first principles calculation method for the velocity distribution function of electrons, and related swarm characteristics, at arbitrary η. Simulation results are presented for electrons in argon gas, for density ratios between zero and 10-1, representing the limits of a negligible electron density and an almost complete Maxwellization of the velocity distribution function, respectively. © 2014 AIP Publishing LLC.

Kiraly P.,Hungarian Academy of Sciences
Magnetic Resonance in Chemistry | Year: 2012

The appearance of background signals arising from the NMR probe and tube is a well-known problem of boron NMR spectroscopy. Background suppression may be achieved by using DEPTH, which increases the signal-to-background (S/B) ratio. Although, the quality of such spectra is often adequate, but in the case of rapid relaxation broadened resonances (T 1 < 1 ms), the residual background signals may still hamper the interpretation of the spectra. It was observed that the background signals are practically invisible in solution 10B NMR. The unusual isotopic effect on the (S/B) ratio was interpreted as an inherent consequence of the integer versus half-integer spin of 10B and 11B, respectively. The practicability of 10/11B NMR was compared for a selected set of boron compounds covering the typical range of (S/B) ratio. The application of 11B is more favourable than 10B as long as it is possible to achieve the desired spectral quality by using DEPTH. Otherwise, the 'background-free' appearance of 10B NMR spectra makes 10B a reasonable alternative of 11B DEPTH. This was found typical for compounds having relaxation broadened resonances. The variable temperature (VT) NMR study of an adduct formation process was also presented here as an example of the advantage of 10B over 11B. Copyright © 2012 John Wiley & Sons, Ltd.

Kiss S.,Hungarian Academy of Sciences
Behavioral and Brain Sciences | Year: 2011

In this commentary I argue that the notion of incommensurability can be extended to the child's developing theories of mind. I use Carey's concept of Quinian bootstrapping and show that this learning process can account for the acquisition of the semantics of mental terms. I suggest a distinction among three stages of acquisition and adopt the theory theory of conceptual development. © 2011 Cambridge University Press.

Wang L.,KTH Royal Institute of Technology | Wang X.V.,KTH Royal Institute of Technology | Gao L.,Huazhong University of Science and Technology | Vancza J.,Hungarian Academy of Sciences | Vancza J.,Budapest University of Technology and Economics
CIRP Annals - Manufacturing Technology | Year: 2014

The modern manufacturing industry calls for a new generation of integration models that are more interoperable, intelligent, adaptable and distributed. Evolved from service-oriented architecture, web-based manufacturing and cloud computing, cloud manufacturing is considered worldwide a new enabling technology for manufacturing enterprises to respond quickly and effectively to the changing global market. For Waste Electrical and Electronic Equipment (WEEE) in particular, it is a critical necessity to recycle, reuse and remanufacture WEEE products by setting up a cloud-based information system. In this paper, a novel service-oriented remanufacturing platform is proposed based on the cloud manufacturing concept. © 2014 CIRP.

Bruckmann F.,University of Regensburg | Endrodi G.,University of Regensburg | Kovacs T.G.,Hungarian Academy of Sciences
Journal of High Energy Physics | Year: 2013

We study the physical mechanism of how an external magnetic field influences the QCD quark condensate. Two competing mechanisms are identified, both relying on the interaction between the magnetic field and the low quark modes. While the coupling to valence quarks enhances the condensate, the interaction with sea quarks suppresses it in the transition region. The latter “sea effect” acts by ordering the Polyakov loop and, thereby, reduces the number of small Dirac eigenmodes and the condensate. It is most effective around the transition temperature, where the Polyakov loop effective potential is flat and a small correction to it by the magnetic field can have a significant effect. Around the critical temperature, the sea suppression overwhelms the valence enhancement, resulting in a net suppression of the condensate, named inverse magnetic catalysis. We support this physical picture by lattice simulations including continuum extrapolated results on the Polyakov loop as a function of temperature and magnetic field. We argue that taking into account the increase in the Polyakov loop and its interaction with the low-lying modes is essential to obtain the full physical picture, and should be incorporated in effective models for the description of QCD in magnetic fields in the transition region. © 2013, SISSA.

Mayer I.,Hungarian Academy of Sciences
Journal of Physical Chemistry A | Year: 2014

It is stressed that the two-center exchange energy components lead to a significant lowering of the total molecular energy because of exclusion of self-repulsion, and this is inevitable for covalent bond formation. The success of the two-center bond order index relies on the fact that it gives a qualitative estimate of this important phenomenon. © 2014 American Chemical Society.

Rezen T.,University of Ljubljana | Rozman D.,University of Ljubljana | Pascussi J.-M.,Montpellier University | Monostory K.,Hungarian Academy of Sciences
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2011

Cholesterol biosynthetic and metabolic pathways contain several branching points towards physiologically active molecules, such as coenzyme Q, vitamin D, glucocorticoid and steroid hormones, oxysterols, or bile acids. Sophisticated regulatory mechanisms are involved in maintenance of the homeostasis of not only cholesterol but also other cholesterogenic molecules. In addition to endogenous cues, cholesterol homeostasis needs to accommodate also to exogenous cues that are imported into the body, such as chemicals and medications. Steroid and nuclear receptors together with sterol regulatory element-binding protein (SREBP) mediate the fine tuning of biosynthetic and metabolic routes as well as transports of cholesterol and its derivatives. Similarly, drug/xenobiotic metabolism is the subject to the feedback regulation of cytochrome P450 enzymes and transporters. The regulatory mechanisms that maintain the homeostasis of cholesterogenic molecules and are involved in drug metabolism share similarities. Cholesterol and cholesterogenic compounds (bile acids, glucocorticoids, vitamin D, etc.) regulate the xenosensor signaling in drug-mediated induction of the major drug-metabolizing cytochrome P450 enzymes. The key cellular receptors, pregnane X receptor (PXR), constitutive androstane receptor (CAR), vitamin D receptor (VDR), and glucocorticoid receptor (GR) provide a functional cross-talk between the pathways maintaining cholesterol homeostasis and controlling the expression of drug-metabolizing enzymes. These receptors serve as metabolic sensors, resulting in a coordinate regulation of cholesterogenic compounds metabolism and of the defense against xenobiotic and endobiotic toxicity. Herein we present a comprehensive review of functional interactions between cholesterol homeostasis and drug metabolism involving the main nuclear and steroid receptors. © 2010 Elsevier B.V. All rights reserved.

Demeter A.,Hungarian Academy of Sciences
Journal of Physical Chemistry A | Year: 2014

The fluorescence quantum yield of 9,10-bis(phenylethynyl)anthracene (BPEA) is almost unity in every examined solvent. Using different hydrocarbons, one can make a convenient and sufficiently accurate experimental test for determination of the extent of the refractive index correction needed in fluorescence quantum yield determination on a given fluorometer. By comparison of the measurements in n-pentane-cis-decaline or n-hexane-toluene solvent pairs, the requirement of the n2 correction is confirmed for most of the fluorometers; however, for one of the examined pieces of equipment the necessary correction proved to be slightly lower. By excited state's lifetime measurements, the refractive index dependence of the fluorescence rate coefficient was reexamined. At 25 °C for BPEA the relationship is in agreement with Bakhshiev's prediction: the experimentally determined exponent of n in the rate coefficient deriving equation is around 1.32 using different paraffins as solvents. The negative temperature coefficient of the radiative rate in part originates from the temperature dependence of the refractive index, while also a small intrinsic contribution has been found. © 2014 American Chemical Society.

Schubert A.,Hungarian Academy of Sciences
Scientometrics | Year: 2014

An estimation of the h-index is proposed for cases when the original variable underlying the distribution for which the h-index had been determined was rescaled. Within its validity limits, the approximation can be usefully applied for field normalization, change of time frames or other changes of measurement scales. © 2014, Akadémiai Kiadó, Budapest, Hungary.

Lachenmaier S.M.,Charite - Medical University of Berlin | Deli M.A.,Hungarian Academy of Sciences | Meissner M.,University of Heidelberg | Liesenfeld O.,Charite - Medical University of Berlin
Journal of Neuroimmunology | Year: 2011

Toxoplasma gondii establishes latent infection in the central nervous system of immunocompentent hosts. Toxoplasmic encephalitis is a life threatening reactivation of latent infection in the brain of immunocompromised patients. To further understand the mechanisms of entry into the brain of T. gondii we investigated host molecules and cells involved in the passage of the parasite through the blood-brain barrier. First, using microarrays brain endothelial cells were found to upregulate, among others, chemokines and adhesion molecules following infection with tachyzoites. Using flow cytometry we observed upregulated ICAM-1 expression on the surface of brain endothelial cells following infection; ICAM-1 expression was further increased after pre-incubation with IFN-γ. Compared to RH tachyzoites, ME49 tachyzoites induced a stronger upregulation of ICAM-1 and an earlier and stronger IL-6 and MCP-1 secretion by brain endothelial cells. Using an in vitro coculture model of the BBB (primary glia cells and brain endothelial cells) we found a stronger migration of infected antigen-presenting cells compared to lymphocytes (4.63% vs. 0.6% of all cells) across the BBB. Among all antigen-presenting cells CD11b+/CD11c+ cells showed the highest infection rate, whereas the majority of infected cells that migrated through the blood-brain barrier were CD11b+/CD11c- cells. Infection of PBMCs with type I or type II Toxoplasma strains resulted in similar patterns of cell migration across the in vitro BBB model.In conclusion, these results suggest that T. gondii modulates gene expression of brain endothelial cells to promote its own migration through the blood-brain barrier in a 'Trojan horse' manner. Cells expressing CD11b either with or without CD11c are likely candidate cells for the intracellular transport of T. gondii across the BBB. T. gondii type I and type II strains induced similar migration patterns of antigen-presenting cells across the in vitro BBB. © 2010 Elsevier B.V.

Chen X.,University of Electronic Science and Technology of China | Chen X.,International Institute For Applied Systems Analysis | Szolnoki A.,Hungarian Academy of Sciences | Szolnoki A.,Institute of Mathematics | Perc M.,University of Maribor
New Journal of Physics | Year: 2014

Cooperators that refuse to participate in sanctioning defectors create the second-order free-rider problem. Such cooperators will not be punished because they contribute to the public good, but they also eschew the costs associated with punishing defectors. Altruistic punishers - those that cooperate and punish - are at a disadvantage, and it is puzzling how such behaviour has evolved. We show that sharing the responsibility to sanction defectors rather than relying on certain individuals to do so permanently can solve the problem of costly punishment. Inspired by the fact that humans have strong but also emotional tendencies for fair play, we consider probabilistic sanctioning as the simplest way of distributing the duty. In well-mixed populations the public goods game is transformed into a coordination game with full cooperation and defection as the two stable equilibria, while in structured populations pattern formation supports additional counterintuitive solutions that are reminiscent of Parrondos paradox. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Navascues M.,University of Bristol | de la Torre G.,ICFO - Institute of Photonic Sciences | Vertesi T.,Hungarian Academy of Sciences
Physical Review X | Year: 2014

The future progress of semi-device-independent quantum information science depends crucially on our ability to bound the strength of the nonlocal correlations achievable with finite-dimensional quantum resources. In this work, we characterize quantum nonlocality under local dimension constraints via a complete hierarchy of semidefinite programming relaxations. In the bipartite case, we find that the first level of the hierarchy returns nontrivial bounds in all cases considered, allowing us to study nonlocality scenarios with four measurement settings on one side and twelve on the other in a normal desktop. In the tripartite case, we apply the hierarchy to derive a Bell-type inequality that can only be violated when each of the three parties has local dimension greater than 2, hence certifying three-dimensional tripartite entanglement in a device-independent way. Finally, we show how the new method can be trivially modified to detect nonseparable measurements in two-qubit scenarios.

Mezei P.,Hungarian Academy of Sciences | Cserfalvi T.,Aqua Concorde
Sensors (Switzerland) | Year: 2012

Electrolyte Cathode Discharge (ELCAD) spectrometry, a novel sensitive multielement direct analytical method for metal traces in aqueous solutions, was introduced in 1993 as a new sensing principle. Since then several works have tried to develop an operational mechanism for this exotic atmospheric glow plasma technique, however these attempts cannot be combined into a valid model description. In this review we summarize the conceptual and technical problems we found in this upcoming research field of direct sensors. The TG gas temperature and the ne electron density values published up to now for ELCAD are very confusing. These data were evaluated by three conditions. The first is the gas composition of the ELCAD plasma, since TG was determined from the emitted intensity of the N2 and OH bands. Secondly, since the ELCAD is an atmospheric glow discharge, thus, the obtained TG has to be close to the Te electron temperature. This can be used for the mutual validation of the received temperature data. Thirdly, as a consequence of the second condition, the values of TG and ne have to agree with the Engel-Brown approximation of the Saha-equation related to weakly ionized glow discharge plasmas. Application of non-adequate experimental methods and theoretical treatment leads to unreliable descriptions which cannot be used to optimize the detector performance. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Farkas A.,University of Szeged | Kemeny L.,University of Szeged | Kemeny L.,Hungarian Academy of Sciences
British Journal of Dermatology | Year: 2010

Many exogenous factors including excessive alcohol consumption have been associated with psoriasis, but the underlying mechanisms still remain elusive. Drinking worsens therapeutic compliance, and decreases the efficacy and increases the toxicity of systemic antipsoriatic treatments. Excess alcohol intake results in compromised immunity and increased risk of infections, but alcohol can induce proinflammatory cytokine production in various cell types and can increase mitogen-derived lymphocyte proliferation and lymphocyte activation. As we have previously reported, alcohol and one of its metabolites, acetone, induce keratinocyte proliferation and increase the mRNA levels of genes characteristic for proliferating keratinocytes, such as α5 integrin, cyclin D1 and keratinocyte growth factor receptor. Recently the correlation between blood and skin ethanol levels in humans was determined by a transdermal alcohol monitoring device, against the 'gold standard' breath alcohol readings. Based on transdermal alcohol measurements it can be concluded that cutaneous alcohol concentrations can reach levels that induce proinflammatory cytokine production and lymphocyte and keratinocyte proliferation in vitro. It is expected that the development of methodologies measuring transdermal ethanol will provide additional tools to evaluate how alcohol influences skin physiology and different dermatological conditions including psoriasis. Our review focuses on the possible link between alcohol misuse and psoriasis, particularly on the possible role of cutaneous ethanol in precipitating the disease. © 2009 British Association of Dermatologists.

Szarka A.,Budapest University of Technology and Economics | Tomasskovics B.,Budapest University of Technology and Economics | Banhegyi G.,Hungarian Academy of Sciences
International Journal of Molecular Sciences | Year: 2012

The life of any living organism can be defined as a hurdle due to different kind of stresses. As with all living organisms, plants are exposed to various abiotic stresses, such as drought, salinity, extreme temperatures and chemical toxicity. These primary stresses are often interconnected, and lead to the overproduction of reactive oxygen species (ROS) in plants, which are highly reactive and toxic and cause damage to proteins, lipids, carbohydrates and DNA, which ultimately results in oxidative stress. Stress-induced ROS accumulation is counteracted by enzymatic antioxidant systems and non-enzymatic low molecular weight metabolites, such as ascorbate, glutathione and α-tocopherol. The above mentioned low molecular weight antioxidants are also capable of chelating metal ions, reducing thus their catalytic activity to form ROS and also scavenge them. Hence, in plant cells, this triad of low molecular weight antioxidants (ascorbate, glutathione and α-tocopherol) form an important part of abiotic stress response. In this work we are presenting a review of abiotic stress responses connected to these antioxidants. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Toth A.,Hungarian Academy of Sciences
Acta Biologica Szegediensis | Year: 2011

This paper reports on the biology, introduction, spread, damage and the control of Bursaphelenchus xylophilus (STEINER and BUHRER, 1934) NICKLE, 1970. Presenting a significant economic threat, the pinewood nematode is a unique quarantine status species of the genus Bursaphelenchus. The risk of its spread in European coniferous forests is especially high where the insect vectors are present. In Hungary, the pests B. mucronatus and B. vallesianus are present as well as its vector species Monochamus. Considering the health status of domestic planted pines, the severity of storm-damages, global warming, the increased volume of imported wooden packages and insect migration, the likelihood of B. xylophilus invading Hungary and finding favourable conditions keeps increasing.

Magyar K.,Semmelweis University | Magyar K.,Hungarian Academy of Sciences
International Review of Neurobiology | Year: 2011

Selegiline, the R-optical enantiomer of deprenyl (phenyl-isopropyl-methyl-propargylamine), was almost exclusively used MAO-B inhibitor during the past decades to treat Parkinson's disease. Oral treatment prolongs the need of levodopa administration. Selegiline is rapidly metabolized by the microsomal enzymes to amphetamine, methamphetamine, and desmethyl-deprenyl. In addition, the flavin-containing monooxigenase is synthesizing deprenyl-N-oxide. Selegiline in rather low concentrations (10 -9-10 -13M), does not influence MAO-B, but it has an antiapoptotic activity in tissue culture. The neuroprotective effect of selegiline has a biphasic character. In higher concentrations than 10 -7M increases the rate of apoptosis (proapoptotic activity). The metabolites are also taking part in the complex pharmacological activity of selegiline. The simultaneous presence of the pro- and antiapoptotic effects of selegiline and its metabolites frequently hindered its clinical usage. During the past years rasagiline has been introduced to replace selegiline in clinical application. MAO-B inhibitors beside their effect on the enzyme MAO-B could hold different spectrum of pharmacological activities. Selegiline is administered orally and it possesses an intensive "first pass" metabolism. To circumvent the "first pass" metabolism, parenteral administration of the drug might lead to different distribution and pharmacological activity of selegiline. © 2011 Elsevier Inc.

Wang Z.,Hong Kong Baptist University | Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor
Journal of Theoretical Biology | Year: 2014

Evolution of cooperation in the prisoner[U+05F3]s dilemma and the public goods game is studied, where initially players belong to two independent structured populations. Simultaneously with the strategy evolution, players whose current utility exceeds a threshold are rewarded by an external link to a player belonging to the other population. Yet as soon as the utility drops below the threshold, the external link is terminated. The rewarding of current evolutionary fitness thus introduces a time-varying interdependence between the two populations. We show that, regardless of the details of the evolutionary game and the interaction structure, the self-organization of fitness and reward gives rise to distinguished players that act as strong catalysts of cooperative behavior. However, there also exist critical utility thresholds beyond which distinguished players are no longer able to percolate. The interdependence between the two populations then vanishes, and cooperators are forced to rely on traditional network reciprocity alone. We thus demonstrate that a simple strategy-independent form of rewarding may significantly expand the scope of cooperation on structured populations. The formation of links outside the immediate community seems particularly applicable in human societies, where an individual is typically member in many different social networks. © 2014 Elsevier Ltd.

Exact solutions are presented of the Klein-Gordon equation of a charged particle moving in a transverse monochromatic plasmon wave of arbitrary high amplitude, which propagates in an underdense plasma. These solutions are expressed in terms of Ince polynomials, forming a doubly infinite set, parametrized by discrete momentum components of the charged particle's de Broglie wave along the polarization vector and along the propagation direction of the plasmon radiation. The envelope of the exact wavefunctions describes a high-contrast periodic structure of the particle density on the plasma length scale, which may have relevance in novel particle acceleration mechanisms. © 2014 Astro Ltd.

Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor
Physical Review X | Year: 2014

Economic experiments reveal that humans value cooperation and fairness. Punishing unfair behavior is therefore common, and according to the theory of strong reciprocity, it is also directly related to rewarding cooperative behavior. However, empirical data fail to confirm that positive and negative reciprocity are correlated. Inspired by this disagreement, we determine whether the combined application of reward and punishment is evolutionarily advantageous. We study a spatial public goods game, where in addition to the three elementary strategies of defection, rewarding, and punishment, a fourth strategy that combines the latter two competes for space. We find rich dynamical behavior that gives rise to intricate phase diagrams where continuous and discontinuous phase transitions occur in succession. Indirect territorial competition, spontaneous emergence of cyclic dominance, as well as divergent fluctuations of oscillations that terminate in an absorbing phase are observed. Yet, despite the high complexity of solutions, the combined strategy can survive only in very narrow and unrealistic parameter regions. Elementary strategies, either in pure or mixed phases, are much more common and likely to prevail. Our results highlight the importance of patterns and structure in human cooperation, which should be considered in future experiments.

Nemes-Incze P.,Research Institute for Technical Physics and Materials Science | Magda G.,Budapest University of Technology and Economics | Kamaras K.,Hungarian Academy of Sciences | Biro L.P.,Research Institute for Technical Physics and Materials Science
Nano Research | Year: 2010

Graphene has many advantageous properties, but its lack of an electronic band gap makes this two-dimensional material impractical for many nanoelectronic applications, for example, field-effect transistors. This problem can be circumvented by opening up a confinement-induced gap, through the patterning of graphene into ribbons having widths of a few nanometres. The electronic properties of such ribbons depend on both their size and the crystallographic orientation of the ribbon edges. Therefore, etching processes that are able to differentiate between the zigzag and armchair type edge terminations of graphene are highly sought after. In this contribution we show that such an anisotropic, dry etching reaction is possible and we use it to obtain graphene ribbons with zigzag edges. We demonstrate that the starting positions for the carbon removal reaction can be tailored at will with precision. © The Author(s) 2010.

Orosz F.,Hungarian Academy of Sciences
Biochemical and Biophysical Research Communications | Year: 2015

Recently, Aoki et al. [15] have been published a paper (Biochem. Biophys. Res. Commun. 445 (2014) 357-362.) in which they identified possible downstream genes required for the extension of peripheral axons in primary sensory neurons of zebrafish. Tppp was claimed as one of them but, as I show, it is the tppp3-like gene, a paralog of tppp, which plays this role. There are three tppp paralogs in fishes: tppp1 (named also tppp ), tppp3 and tppp3-like. Tppp1 and tppp3 are the orthologs of the corresponding human genes, however, the classification of the third one is ambiguous. It is known that the genomes of the early vertebrate lineage underwent two complete genome duplications, which result in the presence of several paralogs in vertebrates. A teleost fish specific third whole genome duplication also occurred. Thus the tppp3-like gene can be either an ortholog of human TPPP2 or a fourth paralog ( tppp4) absent in tetrapods but present in fishes; finally a tppp3a gene which can be originated from the third, fish specific, whole genome duplication. Comparing the sequences of vertebrate and recently available lamprey tppps I show that the tppp3-like gene is a TPPP2 ortholog. Synteny data are in accordance with this suggestion. © 2015, Elsevier Inc. All rights reserved.

Hvizdos P.,Slovak Academy of Sciences | Dusza J.,Slovak Academy of Sciences | Balazsi C.,Hungarian Academy of Sciences
Journal of the European Ceramic Society | Year: 2013

Mechanical and tribological properties of nanocomposites with silicon nitride matrix with addition of 1 and 3. wt% of various types of graphene platelets were studied. The wear behavior was observed by means of the ball-on-disk technique with a silicon nitride ball used as the tribological counterpart at room temperature in dry sliding. Coefficient of friction and specific wear rates were calculated and related to the damage mechanisms observed in the wear tracks. The measured properties were then assessed with respect to the type and volume fraction of the graphene additives. It is shown that addition of such amounts of carbon phases does not lower the coefficient of friction. Graphene platelets seem to be integrated into the matrix very strongly and they do not participate in lubricating processes. The best performance offers materials with 3. wt% of larger sized graphene, which have the highest wear resistance. © 2013 Elsevier Ltd.

Banreti Z.,Hungarian Academy of Sciences
Clinical Linguistics and Phonetics | Year: 2010

This study investigates how aphasic impairment impinges on syntactic and/or semantic recursivity of human language. A series of tests has been conducted with the participation of five Hungarian speaking aphasic subjects and 10 control subjects. Photographs representing simple situations were presented to subjects and questions were asked about them. The responses are supposed to involve formal structural recursion, but they contain semantic-pragmatic operations instead, with 'theory of mind' type embeddings. Aphasic individuals tend to exploit the parallel between 'theory of mind' embeddings and syntactic-structural embeddings in order to avoid formal structural recursion. Formal structural recursion may be more impaired in Broca's aphasia and semantic recursivity may remain selectively unimpaired in this type of aphasia. © 2010 Informa UK Ltd.

A method based on set and graph operations was developed to find and track related entities of sunspot groups on a series of consecutive solar images. Of course, if we can track entities of a sunspot group, we can also track various properties (e.g., position, area, magnetic field, and intensity) associated with them. A new higher-level sunspot-group entity belonging to the whole image series, a family, was introduced to cope with the mergings and separations of various sunspot group entities. To demonstrate the usefulness of the method, it was applied to NOAA AR 11429 using Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) images. This large sunspot group produced several X, M, and C class flares, among others, an X5.4 class flare on 2012 March 7. Abrupt transient and permanent variations in the mean line-of-sight (LOS) magnetic field of the large umbra families were found during the X5.4 flare. Two small umbra families immediately next to the polarity inversion line (PIL) and facing each other at opposite sides of the PIL exhibited abrupt stepwise changes in their mean LOS magnetic field during the X5.4 flare. The family with positive polarity decreased and the family with negative polarity increased. Some of the large umbra families also showed abrupt decrease in their darkness during the flare. We conjecture that an umbra family being a part of a long, narrow magnetic field strip pushing in an opposite magnetic polarity penumbral domain might be one of the triggering causes of several flares. Flare-related changes were observed at every spatial scale of the studied sunspot group. Two of the large opposite-polarity umbra families underwent shearing and converging motions. The break and the turning points of the motion curves of these families were related to flares. Some of the flares coincided with abrupt changes in the motion curves. © 2015, Springer Science+Business Media Dordrecht.

Gyarfas A.,Hungarian Academy of Sciences | Sarkozy G.N.,Worcester Polytechnic Institute
Combinatorics Probability and Computing | Year: 2012

R. H. Schelp conjectured that if G is a graph with |V(G)| = R(P n, P n) such that δ(G) > 3|V(G)|/4, then in every 2-colouring of the edges of G there is a monochromatic P n. In other words, the Ramsey number of a path does not change if the graph to be coloured is not complete but has large minimum degree. Here we prove Ramsey-type results that imply the conjecture in a weakened form, first replacing the path by a matching, showing that the star-matching-matching Ramsey number satisfying R(S n, nK 2, nK 2) = 3n - 1. This extends R(nK 2, nK 2) = 3n - 1, an old result of Cockayne and Lorimer. Then we extend this further from matchings to connected matchings, and outline how this implies Schelp's conjecture in an asymptotic sense through a standard application of the Regularity Lemma. It is sad that we are unable to hear Dick Schelp's reaction to our work generated by his conjecture. © 2012 Cambridge University Press.

Glanzel W.,Catholic University of Leuven | Glanzel W.,Hungarian Academy of Sciences
Scientometrics | Year: 2010

The tail properties of scientometric distributions are studied in the light of the h-index and the characteristic scores and scales. A statistical test for the h-core is presented and illustrated using the example of four selected authors. Finally, the mathematical relationship between the h-index and characteristic scores and scales is analysed. The results give new insights into important properties of rank-frequency and extreme-value statistics derived from scientometric and informetric processes. © 2009 Akadémiai Kiadó, Budapest, Hungary.

Krar M.,University of Pannonia | Kovacs S.,University of Pannonia | Kallo D.,Hungarian Academy of Sciences | Hancsok J.,University of Pannonia
Bioresource Technology | Year: 2010

The importance of the economical production and usage of new generation biofuels, the so-called bio gas oil (paraffins from triglycerides) and the results of the investigation for their productability on the CoMo/Al2O3 catalyst, which was activated by reduction, are presented. The conversion of triglycerides, the yield of total organic fractions and the target product, furthermore the type and ratio of deoxygenation reactions were determined as a function of process parameters. The advantageous process parameters were found (380°C, 40-60bar, 500-600Nm3/m3 H2/sunflower oil ratio, 1.0h-1), where the conversion of triglycerides was 100% and the yield of the target fraction [high paraffin containing (>99%) gas oil boiling range product] was relatively high (73.7-73.9%). The deoxygenation of triglycerides the reduction as well as the decarboxylation/decarbonylation reactions took place. The yield of the target fractions did not achieve the theoretical values (81.4-86.5%). That is why it is necessary to separate the target fraction and recirculate the heavy fraction. © 2010 Elsevier Ltd.

Zavoti J.,Hungarian Academy of Sciences
Acta Geodaetica et Geophysica Hungarica | Year: 2012

The laws of nature in general, and the relations and laws in geodesy in particular can be expressed in most cases by nonlinear equations which are in general solved by transforming them to linear form and applying iteration. The process of bringing the equations to linear form implies neglections and approximation. In certain cases it is possible to obtain exact, correct solutions for nonlinear problems. In the present work we introduce parameters into the rotation matrix, and using this we derive solutions for the 2D and 3D similarity transformations. This method involves no iteration, and it does not require the transformation of the equations to linear form. The scale parameter is determined in both cases by solving a polynomial equation of second degree. This solution is already known, but our derivation is worth consideration because of its simple nature.

Zsiros T.,Hungarian Academy of Sciences
Acta Geodaetica et Geophysica Hungarica | Year: 2012

In the region of the Carpathian-Pannonian Basin (44-50N; 13-28E) 81 earthquakes have moment magnitude (M w); 61 of them are crustal events (focal depth <65 km) while 20 earthquakes belong to the intermediate focal depth region of the Vrancea (Romania) zone. For crustal events the regression of moment magnitude (M w) on local magnitude (M) shows a better fit for large magnitudes using a second order equation against to a linear relationship, and the actual quadratic formula based on 61 events is the following: M w = 1.37(0.28) + 0.39(0.18)M l + 0.061(0.026)M 2(M w :1.9-5.5;M l :1.4-5.5). In the intermediate focal depth Vrancea zone of the south-eastern bend of the Carpathians (44.5-46.5N; 25.5-28.0E) the number of body wave magnitudes is the largest one (20) among the local (8), the surface wave (14) and the duration (17) magnitudes. The linear relationship between the moment (M w) and the body wave (M b) magnitudes has the following form: M w = 1.20(0.08)M b-0.76(0.40)(M w :4.1-7.7;M b :3.8-7.3). The relationships of the different (M l, M s, M b, M d) magnitudes are also presented in the paper.

Motter A.E.,Northwestern University | Gruiz M.,Eotvos Lorand University | Karolyi G.,Budapest University of Technology and Economics | Tel T.,Eotvos Lorand University | Tel T.,Hungarian Academy of Sciences
Physical Review Letters | Year: 2013

Chaos is an inherently dynamical phenomenon traditionally studied for trajectories that are either permanently erratic or transiently influenced by permanently erratic ones lying on a set of measure zero. The latter gives rise to the final state sensitivity observed in connection with fractal basin boundaries in conservative scattering systems and driven dissipative systems. Here we focus on the most prevalent case of undriven dissipative systems, whose transient dynamics fall outside the scope of previous studies since no time-dependent solutions can exist for asymptotically long times. We show that such systems can exhibit positive finite-time Lyapunov exponents and fractal-like basin boundaries which nevertheless have codimension one. In sharp contrast to its driven and conservative counterparts, the settling rate to the (fixed-point) attractors grows exponentially in time, meaning that the fraction of trajectories away from the attractors decays superexponentially. While no invariant chaotic sets exist in such cases, the irregular behavior is governed by transient interactions with transient chaotic saddles, which act as effective, time-varying chaotic sets. © 2013 American Physical Society.

Tsoncheva T.,Bulgarian Academy of Science | Sarkadi-Priboczki E.,Hungarian Academy of Sciences
Applied Surface Science | Year: 2011

11C-radiolabeling technique is applied to investigate methanol decomposition on copper oxide modified SBA-15. Nitrogen physisorption, XRD, FTIR, UV-vis and TPR techniques are used for catalyst characterization. Selective adsorption coverage of the catalytic active sites with 11C- and 12C-methanol molecules is carried out and the products of their conversion are followed. The mechanism of methyl formate, methylal and CO 2 formation from methanol is discussed. ©2011 Elsevier B.V. All rights reserved.

Toth L.,Hungarian Academy of Sciences
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2013

Rectifier neurons differ from standard ones only in that the sigmoid activation function is replaced by the rectifier function, max(0, x). This modification requires only minimal changes to any existing neural net implementation, but makes it more effective. In particular, we show that a deep architecture of rectifier neurons can attain the same recognition accuracy as deep neural networks, but without the need for pre-training. With 4-5 hidden layers of rectifier neurons we report 20.8% and 19.8% phone error rates on TIMIT (with CI and CD units, respectively), which are competitive with the best results on this database. © 2013 IEEE.

Vegh A.G.,Hungarian Academy of Sciences
Journal of biomedicine & biotechnology | Year: 2011

Indolicidin, a cationic antimicrobial tridecapeptide amide, is rich in proline and tryptophan residues. Its biological activity is intensively studied, but the details how indolicidin interacts with membranes are not fully understood yet. We report here an in situ atomic force microscopic study describing the effect of indolicidin on an artificial supported planar bilayer membrane of dipalmitoyl phosphatidylcholine (DPPC) and on purple membrane of Halobacterium salinarum. Concentration dependent interaction of the peptide and membranes was found in case of DPPC resulting the destruction of the membrane. Purple membrane was much more resistant against indolicidin, probably due to its high protein content. Indolicidin preferred the border of membrane disks, where the lipids are more accessible. These data suggest that the atomic force microscope is a powerful tool in the study of indolicidin-membrane interaction.

Bennett S.M.,University of Sheffield | Erdelyi R.,University of Sheffield | Erdelyi R.,Hungarian Academy of Sciences
Astrophysical Journal | Year: 2015

A new generation of solar telescopes has led to an increase in the resolution of localized features seen on the Sun spatially, temporally, and spectrally, enabling a detailed study of macrospicules. Macrospicules are members of a wide variety of solar ejecta and ascertaining where they belong in this family is vitally important, particularly given that they are chromospheric events which penetrate the transition region and lower corona. We examine the overall properties of macrospicules, both temporal and spatial. We also investigate possible relationships between the macrospicule properties and the sample time period itself, which is selected as a proxy for the ramp from solar minimum to solar maximum. Measurements are taken using the Solar Dynamic Observatory to provide the necessary temporal resolution and coverage. At each point in time, the length of the macrospicule is measured from base to tip and the width is recorded at half the length at each step. The measurements were then applied to determine the statistical properties and relationships between them. It is evident that the properties of maximum velocity, maximum length, and lifetime are all related in specific, established terms. We provide appropriate scaling in terms of the physical properties, which would be a useful test bed for modeling. Also, we note that the maximum lengths and lifetimes of the features show some correlation with the sample epoch and, therefore, by proxy the solar minimum to maximum ramp. © 2015. The American Astronomical Society. All rights reserved.

Cheilaris P.,Ben - Gurion University of the Negev | Toth G.,Hungarian Academy of Sciences
Journal of Discrete Algorithms | Year: 2011

We investigate the relationship between two kinds of vertex colorings of graphs: unique-maximum colorings and conflict-free colorings. In a unique-maximum coloring, the colors are ordered, and in every path of the graph the maximum color appears only once. In a conflict-free coloring, in every path of the graph there is a color that appears only once. We also study computational complexity aspects of conflict-free colorings and prove a completeness result. Finally, we improve lower bounds for those chromatic numbers of the grid graph. © 2011 Elsevier B.V. © 2011 Elsevier B.V. All rights reserved.

Heberger K.,Hungarian Academy of Sciences | Zenkevich I.G.,Saint Petersburg State University
Journal of Chromatography A | Year: 2010

The comparison of different polarity measures (parameters, descriptors, variables, scales, etc.) indicates that evaluation of interrelations between these measures is important for better understanding and interpretation of chemical and/or analytical data, especially for chromatographic separation. The best linear correlation between gas chromatographic and non-chromatographic polarity descriptors is revealed for the first time: this pair of variables is the difference of gas chromatographic retention indices on standard polar and non-polar phases as well as the difference between non-dimensional indices of boiling points (known in chromatography since mid-1980s as dispersion indices) and indices of molar refractions. The correlation helps chromatographers to find preferable chemical variables (features) to understand better the separation phenomena and to find better correlations in QSRR models. Principal component analysis (PCA) of ten frequently applied polarity measures shows their similarity and, at the same time, it shows the absence of anomalies within the set of simple organic molecules. A novel ranking method for ten polarity parameters points out that the two most informative polarity measures are (i) the non-dimensional index for boiling point and (ii) the difference in chromatographic retention indices on standard polar and non-polar stationary phases. On the other hand, the hydrophobicity parameter, log P, sometimes considered as polarity parameter in HPLC seems to be the worst one in description of "polarity" in gas chromatography. Surprisingly, such polarity measures like dipole moment and permittivity used often in organic chemistry does not provide the best correlation with gas chromatographic polarity measures. © 2010 Elsevier B.V.

Stirling A.,Hungarian Academy of Sciences
Journal of Physical Chemistry B | Year: 2011

Ab initio molecular dynamics simulations have been performed to study the dissolution of CO2 in water at high pH. The CO2 + OH - → HCO3- forward and the HCO3- → CO2 + OH- reverse paths have been simulated by employing the metadynamics technics. We have found that the free energy barrier along the forward direction is predominantly hydration related and significantly entropic in origin, whereas the backward barrier is primarily enthalpic. The main motifs in the forward mechanism are the structural diffusion of the hydroxyl ion to the first hydration sphere of CO2, its desolvation, and the C-O bond formation in concert with the CO2 bending within the hydrate cavity. In the reverse reaction, the origin of the barrier is the rupture of the strong C-O(H) bond. The present findings support the notion that the free energy barrier of the bicarbonate formation is strongly solvation related but provide also additional mechanistic details at the molecular level. © 2011 American Chemical Society.

Horvath J.,Hungarian Academy of Sciences
Brain Research | Year: 2015

A number studies have shown that the auditory N1 event-related potential (ERP) is attenuated when elicited by self-induced or self-generated sounds. Because N1 is a correlate of auditory feature- and event-detection, it was generally assumed that N1-attenuation reflected the cancellation of auditory re-afference, enabled by the internal forward modeling of the predictable sensory consequences of the given action. Focusing on paradigms utilizing non-speech actions, the present review summarizes recent progress on action-related auditory attenuation. Following a critical analysis of the most widely used, contingent paradigm, two further hypotheses on the possible causes of action-related auditory ERP attenuation are presented. The attention hypotheses suggest that auditory ERP attenuation is brought about by a temporary division of attention between the action and the auditory stimulation. The pre-activation hypothesis suggests that the attenuation is caused by the activation of a sensory template during the initiation of the action, which interferes with the incoming stimulation. Although each hypothesis can account for a number of findings, none of them can accommodate the whole spectrum of results. It is suggested that a better understanding of auditory ERP attenuation phenomena could be achieved by systematic investigations of the types of actions, the degree of action-effect contingency, and the temporal characteristics of action-effect contingency representation-buildup and -deactivation. This article is part of a Special Issue entitled SI: Prediction and Attention.

Osi A.,Hungarian Academy of Sciences | Buffetaut E.,CNRS ENS Geology Laboratory
Annales de Paleontologie | Year: 2011

Hitherto unpublished remains of non-avian and avian theropods from the Late Cretaceous (Formation Csehbánya, Santonian) Iharkút locality (western Hungary) are described. Non-avian theropod remains include an abelisaurid femur, which confirms the presence of this theropod family at Iharkút, and a metacarpal and a tibiotarsus from a paravian which may belong to Pneumatoraptor fodori, previously described from Iharkút. Birds are represented by two femora which clearly belong to enantiornithines, possibly to Bauxitornis, previously described from Iharkút. The abelisauroid record from the Cretaceous of Europe is reviewed. © 2011 Elsevier Masson SAS.

Neuropeptides of the hypothalamic arcuate nucleus (ARC) regulate important homeostatic and endocrine functions and also play critical roles in pubertal development. Altered peptidergic and amino acidergic neurotransmission accompanying pubertal maturation of the ARC are not fully understood. Here we studied the developmental shift in the gene expression profile of the ARC of male mice. RNA samples for quantitative RT-PCR studies were isolated from the ARC of day-14 infantile and day-60 adult male mice with laser-capture microdissection. The expression of 18 neuropeptide-, 15 neuropeptide receptor-, 4 sex steroid receptor and 6 classic neurotransmitter marker mRNAs were compared between the two timepoints. Adult animals showed increased mRNA levels encoding cocaine- and amphetamine-regulated transcript, galanin-like peptide, dynorphin, kisspeptin, proopiomelanocortin, proenkephalin and galanin and reduced expression of mRNAs for pituitary adenylate cyclase activating peptide, calcitonin gene-related peptide, neuropeptide Y, substance P, agouti-related protein, neurotensin and growth hormone-releasing hormone. From the neuropeptide receptors tested, melanocortin receptor-4 showed the most striking (5-fold) increase. Melanocortin receptor-3 and the Y1 and Y5 neuropeptide Y receptors increased 1.5-1.8-fold, whereas δ-opioid receptor and neurotensin receptor-1 transcripts were reduced by 27 and 21%, respectively. Androgen-, progesterone- and α-estrogen receptor transcripts increased by 54-72%. The mRNAs of glutamic acid decarboxylase 65, and 67, vesicular GABA transporter and choline acetyltransferase remained unchanged. Tyrosine hydroxylase mRNA increased by 44%, whereas type-2 vesicular glutamate transporter mRNA decreased by 43% by adulthood. Many of the developmental changes we revealed in this study suggest reduced inhibitory and/or enhanced excitatory neuropeptidergic drive on fertility in adult animals. © 2015 S. Karger AG, Basel Copyright © 2015, S. Karger AG. All rights reserved.

Schubert A.,Hungarian Academy of Sciences
Scientometrics | Year: 2013

The "Jaccardized Czekanowski index", JCz, an indicator measuring the similarity between the cited and citing journal list of a given journal is proposed in the paper. It is shown that the indicator characterizes the network properties of individual journals and, in aggregated form, also that of subject categories or countries. For subject categories, JCz appears to be related to the multidisciplinarity of the category. For countries, the multinational or local character of the publishers seems to have determining role. © 2012 Akadémiai Kiadó, Budapest, Hungary.

Glanzel W.,Catholic University of Leuven | Glanzel W.,Hungarian Academy of Sciences
Scientometrics | Year: 2013

The present paper attempts to shed light on outstanding research performance using the example of citation distributions. In order to answer the question of how the analysis of outstanding performance, in general, and highly cited papers, in particular, could be integrated into standard techniques of evaluative scientometrics. Two general methods are proposed: One solution aims at quantifying the performance represented by the tail of citation distributions independently of the "mainstream", the second one, a parameter-free solution, provides performance classes for any level. Advantages and shortcoming of both methods are discussed. © 2013 Akadémiai Kiadó, Budapest, Hungary.

Liu Y.,Biomedical Imaging Center | Villamena F.A.,Biomedical Imaging Center | Villamena F.A.,Ohio State University | Rockenbauer A.,Hungarian Academy of Sciences | And 2 more authors.
Journal of the American Chemical Society | Year: 2013

Highly asymmetric exchange-coupled biradicals, e.g., the trityl-nitroxides (TNs), possess particular magnetic properties that have opened new possibilities for their application in biophysical, physicochemical, and biological studies. In the present work, we investigated the effect of the linker length on the spin-spin coupling interaction (J) in TN biradicals using the newly synthesized biradicals CT02-GT, CT02-AT, CT02-VT, and CT02-PPT as well as the previously reported biradicals TNN14 and TN1. The results show that the magnitude of J can be easily tuned from ∼4 G (conformer 1 in CT02-PPT) to >1200 G (in TNN14) by varying the linker separating the two radical moieties and changing the temperature. Computer simulations of EPR spectra were carried out to estimate J values of the TN biradicals directly. In addition to the spin-spin coupling interaction of TN biradicals, their g, hyperfine-splitting, and zero-field-splitting interactions were explored at low temperature (220 K). Our present study clearly shows that varying the spin-spin interaction as a function of linker distance and temperature provides an effective strategy for the development of new TN biradicals that can find wide applications in relevant fields. © 2013 American Chemical Society.

Utasi A.,Hungarian Academy of Sciences
Proceedings - International Conference on Pattern Recognition | Year: 2012

This paper addresses the problem of binary classifier learning when the training data is imbalanced, i.e. The samples of the two classes have significantly different cardinality. We investigate two different cost-sensitive approaches in the conditional mutual information (CMI) based weak classifier selection procedure using histogram descriptors. The first method uses CMI for classifier selection, and cost factors are utilized in the construction of the final boosted classifier using support vector machine learning. In the second approach these costs are incorporated into the classifier selection step by weighting the CMI (wCMI). We evaluate the proposed methods in object recognition and detection tasks using two popular histogram-like descriptors. Extensive experiments showed that the proposed methods provide efficient tools to address both problems. © 2012 ICPR Org Committee.

Erds G.,Hungarian Academy of Sciences | Balogh A.,Imperial College London
Astrophysical Journal | Year: 2014

We studied the magnetic flux density carried by solar wind to various locations in the heliosphere, covering a heliospheric distance range of 0.3-5.4 AU and a heliolatitudinal range from 80° south to 80°north. Distributions of the radial component of the magnetic field, BR, were determined over long intervals from the Helios, ACE, STEREO, and Ulysses missions, as well as from using the 1 AU OMNI data set. We show that at larger distances from the Sun, the fluctuations of the magnetic field around the average Parker field line distort the distribution of BR to such an extent that the determination of the unsigned, open solar magnetic flux density from the average 〈|BR|〉 is no longer justified. We analyze in detail two methods for reducing the effect of fluctuations. The two methods are tested using magnetic field and plasma velocity measurements in the OMNI database and in the Ulysses observations, normalized to 1 AU. It is shown that without such corrections for the fluctuations, the magnetic flux density measured by Ulysses around the aphelion phase of the orbit is significantly overestimated. However, the matching between the in-ecliptic magnetic flux density at 1 AU (OMNI data) and the off-ecliptic, more distant, normalized flux density by Ulysses is remarkably good if corrections are made for the fluctuations using either method. The main finding of the analysis is that the magnetic flux density in the heliosphere is fairly uniform, with no significant variations having been observed either in heliocentric distance or heliographic latitude. © 2014. The American Astronomical Society. All rights reserved.

Schottler M.A.,Max Planck Institute of Molecular Plant Physiology | Toth S.Z.,Max Planck Institute of Molecular Plant Physiology | Toth S.Z.,Hungarian Academy of Sciences
Frontiers in Plant Science | Year: 2014

The composition of the photosynthetic apparatus of higher plants is dynamically adjusted to long-term changes in environmental conditions such as growth light intensity and light quality, and to changing metabolic demands for ATP and NADPH imposed by stresses and leaf aging. By changing photosynthetic complex stoichiometry, a long-term imbalance between the photosynthetic production of ATP and NADPH and their metabolic consumption is avoided, and cytotoxic side reactions are minimized. Otherwise, an excess capacity of the light reactions, relative to the demands of primary metabolism, could result in a disturbance of cellular redox homeostasis and an increased production of reactive oxygen species, leading to the destruction of the photosynthetic apparatus and the initiation of cell death programs. In this review, changes of the abundances of the different constituents of the photosynthetic apparatus in response to environmental conditions and during leaf ontogenesis are summarized. The contributions of the different photosynthetic complexes to photosynthetic flux control and the regulation of electron transport are discussed. © 2014 Schöttler and Tóth.

Burketova L.,Academy of Sciences of the Czech Republic | Trda L.,Academy of Sciences of the Czech Republic | Ott P.G.,Hungarian Academy of Sciences | Valentova O.,Institute of Chemical Technology Prague
Biotechnology Advances | Year: 2015

An increasing demand for environmentally acceptable alternative for traditional pesticides provides an impetus to conceive new bio-based strategies in crop protection. Employing induced resistance is one such strategy, consisting of boosting the natural plant immunity. Upon infections, plants defend themselves by activating their immune mechanisms. These are initiated after the recognition of an invading pathogen via the microbe-associated molecular patterns (MAMPs) or other microbe-derived molecules. Triggered responses inhibit pathogen spread from the infected site. Systemic signal transport even enables to prepare, i.e. prime, distal uninfected tissues for more rapid and enhanced response upon the consequent pathogen attack. Similar defense mechanisms can be triggered by purified MAMPs, pathogen-derived molecules, signal molecules involved in plant resistance to pathogens, such as salicylic and jasmonic acid, or a wide range of other chemical compounds. Induced resistance can be also conferred by plant-associated microorganisms, including beneficial bacteria or fungi. Treatment with resistance inducers or beneficial microorganisms provides long-lasting resistance for plants to a wide range of pathogens. This study surveys current knowledge on resistance and its mechanisms provided by microbe-, algae- and plant-derived elicitors in different crops. The main scope deals with bacterial substances and fungus-derived molecules chitin and chitosan and algae elicitors, including naturally sulphated polysaccharides such as ulvans, fucans or carageenans. Recent advances in the utilization of this strategy in practical crop protection are also discussed. © 2015 Elsevier Inc.

Orosz F.,Hungarian Academy of Sciences
Journal of Molecular Evolution | Year: 2016

Apicomplexan parasites cause serious illnesses, including malaria, in humans and domestic animals. The presence of apicortins is predominantly characteristic of this phylum. All the apicomplexan species sequenced contain an apicortin which unites two conserved domains: DCX and partial p25alpha. This paper identifies novel apicortin orthologs in silico and corrects in several cases the erroneous sequences of hypothetical apicortin proteins of Cryptosporidium, Eimeria, and Theileria genera published in databases. Plasmodium apicortins, except from Plasmodium gallinaceum, differ significantly from the other apicomplexan apicortins. The feature of this ortholog suggests that only orthologs of Plasmodiums hosted by mammals altered significantly. The free-living Chromerida, Chromera velia, and Vitrella brassicaformis, contain three paralogs. Their apicomplexan-type and nonapicomplexan-type apicortins might be “outparalogs.” The fungal ortholog, Rozella allomycis, found at protein level, and the algal Nitella mirabilis, found as Transcriptome Shotgun Assembly (TSA), are similar to the known Opisthokont (Trichoplax adhaerens, Spizellomyces punctatus) and Viridiplantae (Nicotiana tabacum) ones, since they do not contain the long, unstructured N-terminal part present in apicomplexan apicortins. A few eumetazoan animals possess apicortin-like (partial) sequences at TSA level, which may be either contaminations or the result of horizontal gene transfer; in some cases the contamination has been proved. © 2016, Springer Science+Business Media New York.

Osi A.,Hungarian Academy of Sciences | Buffetaut E.,CNRS ENS Geology Laboratory | Prondvai E.,Eotvos Lorand University
Cretaceous Research | Year: 2011

The Late Cretaceous (Santonian) continental vertebrate locality of Iharkút, western Hungary has provided numerous azhdarchid pterosaur remains including the recently described, Bakonydraco galaczi. Since the first report of these fossils, additional remains have been discovered that improve considerably our knowledge of some aspects of the anatomy of azhdarchid pterosaurs. New cranial material described here indicates an edentulous, non-crested premaxillary rostrum in Bakonydraco similar to that of Quetzalcoatlus and reveals that this rostrum was considerably thinner and more lightly built than the relatively massive, pointed mandibular symphysis. In addition, the contact surface of the upper and lower jaws of Bakonydraco at least in the symphyseal region was more similar to Tapejara wellnhoferi than to other azdarchids: the contact is irregular and the premaxilla does not fit closely the rostral part of the mandible. Among the postcranial material the atlas-axis complex possessing lateral pneumatic foramina is of great importance because it further supports the notion of interspecific variability of vertebral pneumaticity among pterosaurs. © 2011 Elsevier Ltd.

Kormos V.,University of Pecs | Gaszner B.,University of Pecs | Gaszner B.,Hungarian Academy of Sciences
Neuropeptides | Year: 2013

Major depression, with its strikingly high prevalence, is the most common cause of disability in communities of Western type, according to data of the World Health Organization. Stress-related mood disorders, besides their deleterious effects on the patient itself, also challenge the healthcare systems with their great social and economic impact. Our knowledge on the neurobiology of these conditions is less than sufficient as exemplified by the high proportion of patients who do not respond to currently available medications targeting monoaminergic systems.The search for new therapeutical strategies became therefore a "hot topic" in neuroscience, and there is a large body of evidence suggesting that brain neuropeptides not only participate is stress physiology, but they may also have clinical relevance. Based on data obtained in animal studies, neuropeptides and their receptors might be targeted by new candidate neuropharmacons with the hope that they will become important and effective tools in the management of stress related mood disorders.In this review, we attempt to summarize the latest evidence obtained using animal models for mood disorders, genetically modified rodent models for anxiety and depression, and we will pay some attention to previously published clinical data on corticotropin releasing factor, urocortin 1, urocortin 2, urocortin 3, arginine-vasopressin, neuropeptide Y, pituitary adenylate-cyclase activating polypeptide, neuropeptide S, oxytocin, substance P and galanin fields of stress research. © 2013 Elsevier Ltd.

Shannon N.,University of Bristol | Penc K.,Hungarian Academy of Sciences | Motome Y.,University of Tokyo
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

The classical bilinear-biquadratic nearest-neighbor Heisenberg antiferromagnet on the pyrochlore lattice does not exhibit conventional Néel-type magnetic order at any temperature or magnetic field. Instead spin correlations decay algebraically over length scales r≳ ξc ∼1/√T, behavior characteristic of a Coulomb phase arising from a strong local constraint. Despite this, its thermodynamic properties remain largely unchanged if Néel order is restored by the addition of a degeneracy-lifting perturbation, e.g., further neighbor interactions. Here we show how these apparent contradictions can be resolved by a proper understanding of way in which long-range Néel order emerges out of well-formed local correlations and identify nematic and vector-multipole orders hidden in the different Coulomb phases of the model. So far as experiment is concerned, our results suggest that where long-range interactions are unimportant, the magnetic properties of Cr spinels which exhibit half-magnetization plateaux may be largely independent of the type of magnetic order present. © 2010 The American Physical Society.

Varro A.,University of Szeged | Varro A.,Hungarian Academy of Sciences | Baczko I.,University of Szeged
Pflugers Archiv European Journal of Physiology | Year: 2010

Sudden death among athletes is very rare (1:50,000-1:100,000 annually) but it is still 2-4 times more frequent than in the age-matched control population and attracts significant media attention. We propose a mechanism underlying sudden cardiac death in athletes that does not relate to myocardial ischemia but is based on repolarization abnormalities due to potassium channel downregulation and can also be best explained by the concurrent presence of several factors such as cardiac hypertrophy (athlete's heart), and/or hypertrophic cardiomyopathy, increased sympathetic tone, genetic defects, drugs, doping agents, food, or dietary ingredients. These factors together can increase the repolarization inhomogeneity of the heart ("substrate") and an otherwise harmless extrasystole ("trigger") occurring with a very unfortunate timing may sometimes induce life-threatening arrhythmias. The effective and possible prevention of sudden cardiac death requires the development of novel cost effective cardiac electrophysiological screening methods. Athletes identified by these tests as individuals at higher proarrhythmic risk should then be subjected to more costly genetic tests in order to uncover possible underlying genetic causes for alterations in ionic channel structure and/or function. © 2010 Springer-Verlag.

Mayer I.,Hungarian Academy of Sciences
Chemical Physics Letters | Year: 2013

The "fuzzy atoms" formalism of analysing the wave function in terms of the three-dimensional (3D) space permits one to obtain "effective atomic orbitals" (3D variants of natural hybrids) from an SCF calculation. It is demonstrated here that a "Hilbert-space" analysis performed in the basis of these "effective AO-s" exactly reproduces the results of the "fuzzy atoms" 3D analysis: the Mulliken net and overlap populations calculated in that special basis coincide with the "fuzzy atoms" net and overlap populations, and the same holds for the bond orders calculated in that basis and in the "fuzzy atoms" framework. © 2013 Elsevier B.V. All rights reserved.

Hozer Z.,Hungarian Academy of Sciences
Annals of Nuclear Energy | Year: 2014

A new numerical algorithm has been developed for the simulation of leaking fuel rods under steady state and transient conditions and the specific parameters of the model for a VVER-440 type NPP have been determined. The steady state model can be applied for the calculation of leaking fuel characteristics using measured iodine and noble gas activity concentration data. The transient model is capable of predicting the 131I activity peak during operational transients. The models are included in the RING code that is part of the on-line monitoring system of the Paks NPP in Hungary. © 2014 Elsevier Ltd. All rights reserved.

Tompa P.,Vrije Universiteit Brussel | Tompa P.,Hungarian Academy of Sciences
Chemical Reviews | Year: 2014

Allostery is a classical regulatory mechanism of proteins in which a signal at 'another site' modifies the activity/function of a protein. In fact, with the recognition of the generality of the structural disorder of proteins and the landscape theory of protein structure, a 'new view' of allostery started to emerge, in which emphasis is placed on ligand-induced shifts in the conformational ensemble of the protein. The ensuing changes in ligand binding/catalytic activity might stem from coupled folding transitions of distinct binding sites or remodeling of the conformational landscape to entropically favor a particular downstream binding/catalytic event. The ensuing sigmoidal binding isotherm cannot be described by a simple saturation; rather, it shows signs of cooperation between ligands. If binding of one ligand weakens that of the others, one can also speak about negative cooperativity. To elucidate the underlying mechanistic changes, two models have been suggested, which, even today, form the basis of our textbook wisdom of this phenomenon.

Tompa P.,Vrije Universiteit Brussel | Tompa P.,Hungarian Academy of Sciences
Trends in Biochemical Sciences | Year: 2012

The suggestion that the native state of many proteins is intrinsically disordered (or, as originally termed, unstructured) is now integral to our general view of protein structure and function. A little more than 10 years ago, however, such challenge to the almost dogmatic 'structure-function paradigm' was pure heresy due to the overwhelming evidence that structure determines function. A decade of steady progress turned skepticism around: this 10-year recap review outlines the situation a decade ago and the major directions of the breathtaking advance achieved by experimental and computational approaches. I show that the evidence for the generality and importance of this phenomenon is now so insurmountable that it demands the inclusion of 'unstructural' biology into mainstream biology and biochemistry textbooks. © 2012 Elsevier Ltd.

Kurucz Z.,University of Aarhus | Kurucz Z.,Hungarian Academy of Sciences | Wesenberg J.H.,National University of Singapore | Molmer K.,University of Aarhus
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

The enhanced collective coupling to weak quantum fields may turn atomic or spin ensembles into an important component in quantum information processing architectures. Inhomogeneous broadening can, however, significantly reduce the coupling and the lifetime of the collective excitation that represent the quantum information. In this paper we show that the width and shape of the inhomogeneous broadening have a striking influence on the dynamics of the cavity-ensemble system and may lead to narrowing of the linewidth of the collective states. We underpin our findings with the examples of a Gaussian and a Lorentzian profile of the inhomogeneity. © 2011 American Physical Society.

Ramos-Cordoba E.,University of Girona | Matito E.,University of Girona | Salvador P.,University of Girona | Mayer I.,Hungarian Academy of Sciences
Physical Chemistry Chemical Physics | Year: 2012

The decomposition of 〈Ŝ2〉 for a general wave function has been carried out in the framework of the Hilbert-space analysis. The one and two-center components fulfill all physical requirements imposed to date. An inherent ambiguity of the Hilbert-space decomposition of a two-electron quantity, in particular using a Mulliken-type scheme, is also discussed in detail. The formalism of effective atomic densities has allowed us to derive in a simple manner appropriate expressions for the decomposition of 〈Ŝ2〉 in the framework of Hilbert space analysis that are consistent with Mulliken population analysis and related quantities. Using a particular mapping we have derived the Hilbert-space expressions also in the framework of Löwdin population analysis in a straightforward manner. The numerical results obtained with the latter formalism have proved to be more robust and reliable. © 2012 the Owner Societies.

Hegedus A.,Hungarian Academy of Sciences
Nuclear Physics B | Year: 2010

Recently a set of functional equations defining the anomalous dimensions of arbitrary local single trace operators in planar N = 4 supersymmetric Yang-Mills theory has been conjectured. These functional equations take the form of a Y-system defined on a special shaped domain. This Y-system can be equivalently reformulated as a T-system defined on a "T-shaped fat-hook". The elements of the T-system satisfy discrete Hirota equations. In the present paper the discrete Hirota equations for AdS/CFT are solved by means of a chain of Bäcklund transformations and as a result TT-, TQ-, and QQ-relations are obtained for AdS/CFT. © 2009 Elsevier B.V. All rights reserved.

Kovacs T.,Hungarian Academy of Sciences
Monthly Notices of the Royal Astronomical Society | Year: 2013

The possible observations of Trojan-like extrasolar planets stimulate the deeper understanding of the stability behaviour of the co-orbital resonant motion. By using Hill's equations and the energy-rate method, an analysis of the stability map of the elliptic-restricted three-body problem is performed. Regions of the μ-e parameter plane are described numerically and related to the resonant frequencies of librational motion. Stability and instability can therefore be obtained by analysing the two independent frequency modes depending on system parameters. The key role of the long period libration in determining the structure of the stability is demonstrated and also a stability mechanism is found that is responsible for extended lifetime of the test particle in the unstable domain of the stability map © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Sipos P.,Hungarian Academy of Sciences
Carpathian Journal of Earth and Environmental Sciences | Year: 2010

There are numerous results on the characteristics of metal sorption by total soil samples or soil clay fractions separately. However, not many have focused on the comparison of these characteristics of total soil and clay fraction samples from the same soil. In this study Cu and Pb batch sorption experiments were carried out on samples from the genetic horizons of two Luvisol profiles characterized by vermiculite and montmorillonite as dominant clay minerals, respectively. Freundlich KF and n parameters for Cu and Pb sorption on the total soil samples unanimously show the primary role of the soil organic matter, as well as the preference of vermiculite over montmorillonite in the retention of both metals. These results were effectively completed by those from the experiments performed on soil clay fractions. It was shown that the generally higher affinity of Pb than Cu to the studied soils is primarily due its very strong affinity to the soil organic components. Additionally, in the studied acidic-slightly acidic Luvisol samples sorption of Pb on clay surfaces seems to be much more inhibited when compared to Cu. Consequently, combined study of sorption properties of total soil samples and soil clay fractions helps us in better understanding the sorption process of potentially toxic metals in soils.

Bajnok Z.,Hungarian Academy of Sciences | el Deeb O.,Roland Eotvos University
Nuclear Physics B | Year: 2010

Form factor axioms are derived in two dimensional integrable defect theories for matrix elements of operators localized both in the bulk and on the defect. The form factors of bulk operators are expressed in terms of the bulk form factors and the transmission factor. The structure of the form factors of defect operators is established in general, and explicitly calculated in particular, for the free boson and for some operator of the Lee-Yang model. Fusion method is also presented to generate boundary form factor solutions for a fused boundary from the known unfused ones. © 2010 Elsevier B.V. All rights reserved.

Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor | Perc M.,King Abdulaziz University
New Journal of Physics | Year: 2014

Deliberate deceptiveness intended to gain an advantage is commonplace in human and animal societies. In a social dilemma, an individual may only pretend to be a cooperator to elicit cooperation from others, while in reality he is a defector. With this as motivation, we study a simple variant of the evolutionary prisoners dilemma game entailing deceitful defectors and conditional cooperators that lifts the veil on the impact of such two-faced behavior. Defectors are able to hide their true intentions at a personal cost, while conditional cooperators are probabilistically successful at identifying defectors and act accordingly. By focusing on the evolutionary outcomes in structured populations, we observe a number of unexpected and counterintuitive phenomena. We show that deceitful behavior may fare better if it is costly, and that a higher success rate of identifying defectors does not necessarily favor cooperative behavior. These results are rooted in the spontaneous emergence of cycling dominance and spatial patterns that give rise to fascinating phase transitions, which in turn reveal the hidden complexity behind the evolution of deception. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Mondello S.,Banyan Biomarkers, Inc. | Buki A.,Hungarian Academy of Sciences | Italiano D.,Messina University | Jeromin A.,Banyan Biomarkers, Inc.
Neurology | Year: 2013

Objective: The study aims to examine α-synuclein in the CSF of patients with severe traumatic brain injury (TBI) and its relationship with clinical characteristics and long-term outcomes. Methods: This prospective case-control study enrolled patients with severe TBI (Glasgow Coma Score ≤8) who underwent ventriculostomy. CSF samples were taken from each TBI patient at admission and daily for up to 8 days after injury and successively assessed by ELISA. Control CSF was collected for analysis from subjects receiving lumbar puncture for other medical reasons. We used trajectory analysis to identify distinct temporal profiles of CSF α-synuclein that were compared with clinical outcomes. Results: CSF α-synuclein was elevated in TBI patients after injury as compared to controls (p = 0.0008). Overall, patients who died had higher concentrations (area under the curve) over 8 days of observation compared to those who survived at 6 months postinjury (p = 0.002). Two distinct temporal α-synuclein profiles were recognized over time. Subjects who died had consistently elevated α-synuclein levels compared to those who survived with α-synuclein levels near controls. High-risk trajectory was a strong and accurate predictor of death with 100%specificity and a very high sensitivity (83%). Conclusions: Taken together, these data support the hypothesis that in severe TBI patients, substantial increase of CSF α-synuclein may indicate widespread neurodegeneration and reflect secondary neuropathologic events occurring after injury. The determination of CSF α-synuclein may be a valuable prognostic marker, adding to the clinical assessment and creating opportunities for medical intervention. © 2013 American Academy of Neurology.

In order to reveal the atomic level structure of liquid carbon tetrabromide, a new synchrotron x-ray diffraction measurement, over a wide momentum transfer (Q-)range, has been performed. These x-ray data have been interpreted together with a neutron diffraction dataset, measured earlier, using the Reverse Monte Carlo method. The structure is analysed on the basis of partial radial distribution functions and distance dependent orientational correlation functions. Orientational correlations behave similarly to other carbon tetrahalides. Moreover, the information content of the new x-ray diffraction dataset, and in particular, of the varying Q-range, is also discussed. Only very small differences have been found between the results of calculations that apply one single experimental structure factor and the ones that use both x-ray and neutron diffraction data: the latter showed slightly more ordered carbon-carbon radial distribution function, which resulted in seemingly more ordered orientational correlations between pairs of molecules. Neither the extended Q-range, nor the application of local invariance constraints yielded significant new information. For providing a simple reference system, a hard sphere model has also been created that can describe most of the partial radial distribution functions and orientational correlations of the real system at a semi-quantitative level. © 2014 Elsevier B.V.

Marx D.,Hungarian Academy of Sciences
Journal of Computer and System Sciences | Year: 2013

We prove that weighted circuit satisfiability for monotone or antimonotone circuits has no fixed-parameter tractable approximation algorithm with any approximation ratio function ρ, unless FPT≠W[1]. In particular, not having such an fpt-approximation algorithm implies that these problems have no polynomial-time approximation algorithms with ratio ρ(OPT) for any nontrivial function ρ. © 2012 Elsevier Inc.

Mayer I.,Hungarian Academy of Sciences
Physical Chemistry Chemical Physics | Year: 2012

An improved SCF energy decomposition scheme is proposed in which a special treatment is introduced for those "ionic" one-center electron-electron repulsion energy contributions which arise from the use of doubly filled bonding orbitals. These terms characterize the bonding pattern rather than the state of the atoms, therefore they are attributed to the bonds and are redistributed between them in accord with the bond orders. This permits one to solve the dilemma which we had with the previous decomposition schemes, and obtain very "chemical" one- and two-center energy components, characterizing well the bonding situation in different molecules.

Toth L.,Hungarian Academy of Sciences
Proceedings of the Annual Conference of the International Speech Communication Association, INTERSPEECH | Year: 2013

Rectifier neurons differ from standard ones only in that the sigmoid activation function is replaced by the rectifier function, max(0, x). Several recent studies suggest that rectifier units may be more suitable building units for deep nets. For example, we found that with deep rectifier networks one can attain a similar speech recognition performance than that with sigmoid nets, but without the need for the time-consuming pre-training procedure. Here, we extend the previous results by modifying the rectifier network so that it has a convolutional structure. As convolutional networks are inherently deep, rectifier neurons seem to be an ideal choice as their building units. Indeed, on the TIMIT phone recognition task we report a 6% relative error reduction compared to our earlier results, giving an 18.6% error rate on the core test set. Then, with the application of the recently proposed 'dropout' training method we reduce the error rate further to 17.8%, which, to our knowledge, is the best result to date on this database. Copyright © 2013 ISCA.

Comas-Vives A.,Autonomous University of Barcelona | Stirling A.,Hungarian Academy of Sciences | Lledos A.,Autonomous University of Barcelona | Ujaque G.,Autonomous University of Barcelona
Chemistry - A European Journal | Year: 2010

The Wacker process consists of the oxidation of ethylene catalyzed by a PdII complex. The reaction mechanism has been largely debated in the literature; two modes for the nucleophilic addition of water to a Pd-coordinated alkene have been proposed: syninner- and anti-outer-sphere mechanisms. These reaction steps have been theoretically evaluated by means of ab initio molecular dynamics combined with metadynamics by placing the [Pd-(C2H 4)Cl2(H2O)] complex in a box of water molecules, thereby resembling experimental conditions at low [Cl-]. The nucleophilic addition has also been evaluated for the [Pd(C 2H4)Cl3]- complex, thus revealing that the water by chloride ligand substitution trans to ethene is kinetically favored over the generally assumed cis species in water. Hence, the resulting trans species can only directly undertake the outersphere nucleophilic addition, whereas the inner-sphere mechanism is hindered since the attacking water is located trans to ethene. In addition, all the simulations from the [Pd(C 2H4)Cl2-(H2O)] species (either cis or trans) support an outer-sphere mechanism with a free-energy barrier compatible with that obtained experimentally, whereas that for the inner-sphere mechanism is significantly higher. Moreover, additional processes for a global understanding of the Wacker process in solution have also been identified, such as ligand substitutions, proton transfers that involve the aquo ligand, and the importance of the trans effect of the ethylene in the nucleophilic addition attack. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two little known genera, Aspar HALAŠKOVÁ, 1977 and Blaszakzercon KEMAL & KOÇAK, 2009 are reviewed. New diagnoses for both genera are provided with short descriptions and previous records of the known species included. Two new Aspar species, A. opisthoisotrichus sp. n. and A. tamalpaisensis sp. n. and furthermore, a new Blaszakzercon species, B. hexagonatus sp. n. are described and illustrated.

Lokshtanov D.,University of Bergen | Marx D.,Hungarian Academy of Sciences
Information and Computation | Year: 2013

We study a family of graph clustering problems where each cluster has to satisfy a certain local requirement. Formally, let μ be a function on the subsets of vertices of a graph G. In the (μ,p,q)-Partition problem, the task is to find a partition of the vertices into clusters where each cluster C satisfies the requirements that (1) at most q edges leave C and (2) μ(C)≤p. Our first result shows that if μ is an arbitrary polynomial-time computable monotone function, then (μ,p,q)-Partition can be solved in time nO(q), i.e., it is polynomial-time solvable for every fixed q. We study in detail three concrete functions μ (the number of vertices in the cluster, number of nonedges in the cluster, maximum number of non-neighbors a vertex has in the cluster), which correspond to natural clustering problems. For these functions, we show that (μ,p,q)-Partition can be solved in time 2O(p)×nO(1) and in time 2 O(q)×nO(1) on n-vertex graphs, i.e., the problem is fixed-parameter tractable parameterized by p or by q. © 2012 Elsevier Inc. All rights reserved.

Equilibrium (based on Henry constants) and kinetic (based on relaxation-time constants or rather macropore transport diffusivities) selectivities for commercial zeolite and carbon-molecular-sieve (CMS) adsorbents were compared. Adsorption isotherms were recorded at -20°. The frequency-response (FR) sorption-rate spectra were determined in the range of -78 and 70° at 133 Pa. In particles of a larger size than 1.0 mm, macropore diffusion governed the rate of sorption mass transport in both types of microporous materials. The differences in the intercrystalline diffusivities established the kinetic separation of the gases notwithstanding the essential importance of interactions in the micropores. Zeolites seem to be more advantageous for a dynamic separation of CO2 and CH4 than CMS 4A. With the CO2 and CO pair, the CMS is characterized by short characteristic times which, together with a good separation factor, is a double advantage in a short-cycle adsorption technology. Upon comminution of the carbon pellets, intercrystalline-diffusion resistance can be completely removed by using CMS 4A adsorbent particles with a diameter smaller than 1 mm. The carbonization of spruce-wood cubes resulted in an excellent carbon honeycomb structure, which seems to be ideal from a dynamic point of view for applications in short-cycle adsorption-separation technologies. In the development of adsorbents, the use of the FR method can be beneficial. © 2011 Verlag Helvetica Chimica Acta AG.

Horvath O.,University of Pannonia | Valicsek Z.,University of Pannonia | Harrach G.,University of Pannonia | Lendvay G.,University of Pannonia | And 2 more authors.
Coordination Chemistry Reviews | Year: 2012

The location of the metal center in the porphyrin complexes strongly depends on its size, charge and spin multiplicity. Metal ions can form normal (in-plane) metalloporphyrins, or several of them, being too large to fit into the coordination cavity of the porphyrin ring, are located above the ligand plane, resulting in out-of-plane (OOP) complexes. The distorted structure of the latter type induces special photophysical and photochemical features that are characteristic of all OOP complexes. Efficient LMCT processes can take place upon excitation of these compounds. In this paper we review the results of recent studies on water-soluble (1:1) porphyrin complexes of several metal ions to reveal how the size (and partly the oxidation state) of the metal center influences their structure and photoinduced behavior. The effects of the pre-distortion (via bromination) and the charge of the porphyrin ligand on the structure and photoreactivity of these complexes are also discussed. While the porphyrin complex of Ag 2+ (r ion=94pm) formed in the reaction of the Ag + ion and the TSPP 6- ligand (H 2TSPP 4-=5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin anion) displays OOP features, the corresponding complex also of open-shell Au 3+ (r ion=85pm) is unambiguously of planar structure, and does not show any fluorescence and photoredox degradation. In the case of the anionic complex of Cd 2+ (r ion=95pm), octabromination of the TSPP 6- ligand results in significant red-shifts in the absorption and emission spectra, dramatically diminishes the fluorescence quantum yield and lifetime, and turns the photodegradation into a very oxygen-sensitive reaction. The axial coordination of HO - ligand further increases the distortion and photoreactivity. The efficiency for the photoinduced LMCT reaction of the cationic complex of Bi 3+ (r ion=103pm) formed with the TMPyP 2+ ligand (H 2TMPyP 4+=5,10,15,20-tetrakis(1-methyl-4-pyridinium)porphyrin cation) is significantly lower than that for anionic BiTSPP 3-, due to the weaker Lewis-basicity of the positively charged porphyrin. DFT calculations of the geometrical structures show good correlation with the observed photophysical and photochemical properties. Deviating from the inner-sphere LMCT reaction of OOP complexes, the cationic ligand (such as TMPyP 2+ and TAPP 2+ (H 2TAPP 4+=5,10,15,20-tetrakis(4-trimethylammonium phenyl)porphyrin cation)) is favorable for the outer-sphere photoinduced reduction of the metal center in the in-plane manganese(III) porphyrins because the anionic porphyrin ligands of higher Lewis-basicity stabilize the +3 oxidation state. The cationic porphyrin ligands enhance the formation of manganese(II) complexes with OOP characteristics, and can be utilized in photocatalytic systems applicable for water splitting. © 2012 Elsevier B.V.

Kovacs D.,Vlaams Instituut Voor Biotechologie | Tompa P.,Vlaams Instituut Voor Biotechologie | Tompa P.,Hungarian Academy of Sciences
Biochemical Society Transactions | Year: 2012

IDPs (intrinsically disordered proteins) represent a unique class of proteins which show diverse molecular mechanisms in key biological functions. The aim of the present mini-review is to summarize IDP chaperones that have increasingly been studied in the last few years, by focusing on the role of intrinsic disorder in their molecular mechanism. Disordered regions in both globular and disordered chaperones are often involved directly in chaperone action, either by modulating activity or through direct involvement in substrate identification and binding. They might also be responsible for the subcellular localization of the protein. In outlining the state of the art, we survey known IDP chaperones discussing the following points: (i) globular chaperones that have an experimentally proven functional disordered region(s), (ii) chaperones that are completely disordered along their entire length, and (iii) the possible mechanisms of action of disordered chaperones. Through all of these details, we chart out how far the field has progressed, only to emphasize the long road ahead before the chaperone function can be firmly established as part of the physiological mechanistic arsenal of the emerging group of IDPs. ©The Authors Journal compilation ©2012 Biochemical Society.

Darko E.,Hungarian Academy of Sciences
Philosophical transactions of the Royal Society of London. Series B, Biological sciences | Year: 2014

Providing an adequate quantity and quality of food for the escalating human population under changing climatic conditions is currently a great challenge. In outdoor cultures, sunlight provides energy (through photosynthesis) for photosynthetic organisms. They also use light quality to sense and respond to their environment. To increase the production capacity, controlled growing systems using artificial lighting have been taken into consideration. Recent development of light-emitting diode (LED) technologies presents an enormous potential for improving plant growth and making systems more sustainable. This review uses selected examples to show how LED can mimic natural light to ensure the growth and development of photosynthetic organisms, and how changes in intensity and wavelength can manipulate the plant metabolism with the aim to produce functionalized foods.

Farkas E.,Hungarian Academy of Sciences
Acta Botanica Hungarica | Year: 2014

Lichenes Delicati Exsiccati Editae of little, fine, special lichens is edited in honour of Antonín Vězda (1920-2008). The foliicolous lichen Coenogonium usambarense was collected by Tamás Pócs, who contributed also often to Vězda's exsiccates and celebrated his 80th birthday in 2013. Herpothallon hypoprotocetraricum was also collected in Africa during a field trip organised by him. It represents isotype material. The third fascicle of the exsiccate is consisted of 15 species and distributed to 12 lichen herbaria of the world.

Farkas E.,Hungarian Academy of Sciences
Acta Botanica Hungarica | Year: 2014

The bibliography of foliicolous lichenised fungi is compiled, listing publications of the last 60 years following Santesson's world monograph on the foliicolous lichens. It consists of 708 scientific papers, journal publications, books, posters, exsiccates, dissertation manuscripts.

Tamas-Nyitrai C.,Hungarian Academy of Sciences
Methods in molecular biology (Clifton, N.J.) | Year: 2012

After rice, wheat is considered to be the most important world food crop, and the demand for high-quality wheat flour is increasing. Although there are no GM varieties currently grown, wheat is an important target for biotechnology, and we anticipate that GM wheat will be commercially available in 10-15 years. In this chapter, we summarize the main features and challenges of wheat transformation and then describe detailed protocols for the production of transgenic wheat plants both by biolistic and Agrobacterium-mediated DNA-delivery. Although these methods are used mainly for bread wheat (Triticum aestivum L.), they can also be successfully applied, with slight modifications, to tetraploid durum wheat (T. turgidum L. var. durum). The appropriate size and developmental stage of explants (immature embryo-derived scutella), the conditions to produce embryogenic callus tissues, and the methods to regenerate transgenic plants under increasing selection pressure are provided in the protocol. To illustrate the application of herbicide selection system, we have chosen to describe the use of the plasmid pAHC25 for biolistic transformation, while for Agrobacterium-mediated transformation the binary vector pAL156 (incorporating both the bar gene and the uidA gene) has been chosen. Beside the step-by-step methodology for obtaining stably transformed and normal fertile plants, procedures for screening and testing transgenic wheat plants are also discussed.

Vertesi T.,Hungarian Academy of Sciences | Navascues M.,Complutense University of Madrid
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

We study under which conditions it is possible to assert that a joint measurement cannot be simulated by local operations and classical communication. More concretely, we consider a scenario where two parties, Alice and Bob, send each a state selected from a labeled set of unknown states to a third party, Charlie, who in turn interacts with the states in some undisclosed way and then announces an outcome. We show that, under the assumption that Alice and Bob know the dimensionality of their systems, there exist situations where the statistics of the outcomes reveals the nature of Charlie's measurement. © 2011 American Physical Society.

Baranyi P.,Hungarian Academy of Sciences
Asian Journal of Control | Year: 2015

The main motivation of the TP model transformation is that modern identification and control analysis, along with design methodologies, are based on various kinds of different representations that have different benefits and drawbacks in terms of identification and modeling effort and structure, however, the link between these representations is in many cases difficult to establish, especially if the model components are not given by closed formulae but rather by various soft-computing-based or black box models. This paper shows that the TP model transformation can serve as a gateway between different representations by bridging to a widely adopted polytopic representation. Further, it is capable of readily manipulating the resulting polytopic representation for further design requirements, which in many cases has a strong effect on the resulting control performance and the conservativeness of the solution. The paper discusses how the TP model transformation can be used as a final step of modeling and, at the same time, as a preprocessing step in polytopic model based design approaches. The paper introduces the generalized TP model transformation, which is a tractable, non-heuristic numerical tool that can be executed on sets of functions. Different manipulation techniques are investigated to show the benefits of the generalized TP model transformation. Finally, a stability verification technique is proposed for cases where system components are available in different representations. © 2015 Chinese Automatic Control Society and Wiley Publishing Asia Pty Ltd.

Kiszely M.M.,Hungarian Academy of Sciences
Carpathian Journal of Earth and Environmental Sciences | Year: 2010

Presently thirteen seismological stations work in Hungary and hundreds of small earthquakes are detected yearly. The magnitude of 80% of the detected seismic events is ML≤2.0. If we compare this to the situation fifty years ago, when the catalogued events contained only the earthquakes that people felt, we understand that today in Hungary an important revolution is taking place in seismology. In this paper we investigate the statistical features of earthquakes and blasts in the Carpathian Basin and adjacent regions (16°-23°E - 44.5°-49°N). Three different methods were performed using data from the period 1995.01.01-2009-08.31 to investigate the existence of periodicities in the seismic events. A midday maxima is verified in the cases of earthquakes and blasts, and we found that there are fewer events on weekend and more during the summer. The increased number of earthquakes around 12 h (MET) might be attributed to the inclusion of quarry blasts among the earthquakes, however natural process might also contribute in triggering instability in a fault approaching the failure threshold around midday. Monthly variations in the distributions of seismic events might not be of physical origin, but connected to the changing sensitivity of the instruments during the seasons. The comparison of the diurnal distribution of earthquakes occurring on weekends and on weekdays indicates the contamination of the Hungarian Earthquake Bulletin with data from quarry blasts.

Temesvari T.,Hungarian Academy of Sciences
Nuclear Physics B | Year: 2010

Replica field theory is used to study the n-dependent free energy of the Ising spin glass in a first order perturbative treatment. Large sample-to-sample deviations of the free energy from its quenched average prove to be Gaussian, independently of the special structure of the order parameter. The free energy difference between the replica symmetric and (infinite level) replica symmetry broken phases is studied in details: the line n (T) where it is zero coincides with the Almeida-Thouless line for d > 8. The dimensional domain 6 < d < 8 is more complicated, and several scenarios are possible. © 2010 Elsevier B.V. All rights reserved.

Jady B.E.,University Paul Sabatier | Ketele A.,University Paul Sabatier | Kiss T.,University Paul Sabatier | Kiss T.,Hungarian Academy of Sciences
Genes and Development | Year: 2012

Alu repetitive sequences are the most abundant short interspersed DNA elements in the human genome. Full-length Alu elements are composed of two tandem sequence monomers, the left and right Alu arms, both derived from the 7SL signal recognition particle RNA. Since Alu elements are common in protein-coding genes, they are frequently transcribed into pre-mRNAs. Here, we demonstrate that the right arms of nascent Alu transcripts synthesized within pre-mRNA introns are processed into metabolically stable small RNAs. The intron-encoded Alu RNAs, termed AIuACA RNAs, are structurally highly reminiscent of box H/ACA small Cajal body (CB) RNAs (scaRNAs). They are composed of two hairpin units followed by the essential H (AnAnnA) and ACA box motifs. The mature AIuACA RNAs associate with the four H/ACA core proteins: dyskerin, Nop10, Nhp2, and Garl. Moreover, the 3′ hairpin of AluACA RNAs carries two closely spaced CB localization motifs, CAB boxes (UGAG), which bind Wdr79 in a cumulative fashion. In contrast to canonical H/ACA scaRNPs, which concentrate in CBs, the AIuACA RNPs accumulate in the nucleoplasm. Identification of 348 human AIuACA RNAs demonstrates that intron-encoded AIuACA RNAs represent a novel, large subgroup of H/ACA RNAs, which are apparently confined to human or primate cells. © 2012 by Cold Spring Harbor Laboratory Press.

Muszbek L.,Debrecen University | Muszbek L.,Hungarian Academy of Sciences | Bagoly Z.,Debrecen University | Cairo A.,University of Milan | Peyvandi F.,University of Milan
Current Opinion in Hematology | Year: 2011

Purpose of Review: Here we review recent developments concerning the diagnosis, classification and treatment of factor XIII (FXIII) deficiency and new findings related to the pathogenesis of the disease. Recent Findings: Most recently, the International Society on Thrombosis and Haemostasis, Scientific and Standardization Committee published a guideline for the diagnosis and classification of FXIII deficiencies. Since 2009, three novel mutations causing severe bleeding diathesis were discovered in the FXIII-A gene and one in the FXIII-B gene. A newly described FXIII-A deficiency was of the extremely rare qualitative type II deficiency. The first well established founder effect was reported for a causative FXIII-A mutation. More than a quarter of all FXIII-A deficiencies are due to autoantibody, among them the first case of deficiency caused by anti-FXIII-B autoantibody was reported in the last 2 years. The safety and effectiveness of plasma FXIII concentrate for prophylaxis and treatment is now well established. The new recombinant FXIII product is currently in phase III clinical trial and the preliminary data are promising. Summary: FXIII deficiency is considered the most underdiagnosed bleeding diathesis. The recommended algorithm for its diagnosis and classification could improve the diagnostic efficiency. The preferred choice for substitution therapy is FXIII concentrate (plasma-derived or, in the future, recombinant). © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Hideg E.,Hungarian Academy of Sciences
Methods in molecular biology (Clifton, N.J.) | Year: 2011

In plants, reactive oxygen species (ROS), also known as active oxygen species (AOS), are associated with normal, physiologic processes as well as with responses to adverse conditions. ROS are connected to stress in many ways: as primary elicitors, as products and propagators of oxidative damage, or as signal molecules initiating defense or adaptation. The photosynthetic electron transport is a major site of oxidative stress by visible or ultraviolet light, high or low temperature, pollutants or herbicides. ROS production can be presumed from detecting oxidatively damaged lipids, proteins, or pigments as well as from the alleviating effects of added antioxidants. On the contrary, measuring ROS by special sensor molecules provides more direct information. This chapter focuses on the application of spin trapping electron paramagnetic resonance (EPR) spectroscopy for detecting ROS: singlet oxygen and oxygen free radicals in thylakoid membrane preparations.

The taxonomic histroy of the genus Prozercon Sellnick, 1943 is summarised. A diagnosis of the genus is given, with remarks on variability of certain characters. The genus Rafas Błaszak, 1979b, which was defined earlier on the basis of its divided sternal shield, is proposed as junior synonym of Prozercon, which results in the following new combinations: P. bisternalis (Błaszak, 1979b) comb. nov. and P. blaszaki (Urhan & Ayyildiz, 1996d) comb. nov. Prozercon changbaiensis Bei et al., 2002 is transferred to Mesozercon Błaszak, 1976 as Mesozercon changbaiensis (Bei et al., 2002) comb. nov., on the basis of the presence of the adgenital gland openings and ventrianal setae ZV1. Prozercon willmanni Schweizer, 1948 was synonymised earlier with a former variety of P. kochi Sellnick, 1944, but is here regarded as a valid species since there are several important characters distinguishing the two species. Prozercon masani Moraza, 2006 is proposed as junior synonym of P. cambriensis Skorupski & Luxton, 1996 since no convincing differences exist between the two species. Six new species, P. achaeanus sp. nov., P. bulbiferus sp. nov., P. dramaensis sp. nov., P. graceus sp. nov., P. morazae sp. nov. and P. norae sp. nov., are described from Greece, and P. carpathofimbriatus and P. carsticus are recorded for the first time from the country. Detailed descriptions of the female and the previously unknown deutonymph are of P. yavuzi Urhan, 1998a also presented, as the Greek specimens differ from the Turkish ones by important characters. A key to the known species of Prozercon is provided. Copyright © 2011 · Magnolia Press.

Molnar O.,Hungarian Academy of Sciences
European Journal of Plant Pathology | Year: 2016

A Fusarium proliferatum strain isolated from diseased oat seeds was shown to be pathogenic on two oat cultivars. During the pathogenicity tests the fungus was re-isolated from the seeds, glumes and stem pieces of the inoculated oat plants. This is the first reported occurrence of F. proliferatum, a fumonisin producing species, as a causal agent of Fusarium head blight of oat in Hungary, and indeed Europe. © 2016 Koninklijke Nederlandse Planteziektenkundige Vereniging

Ivanyos G.,Hungarian Academy of Sciences | Karpinski M.,University of Bonn | Saxena N.,University of Bonn
SIAM Journal on Computing | Year: 2010

We present new deterministic algorithms for several cases of the maximum rank matrix completion problem (for short matrix completion), i.e., the problem of assigning values to the variables in a given symbolic matrix to maximize the resulting matrix rank. Matrix completion is one of the fundamental problems in computational complexity. It has numerous important algorithmic applications, among others, in computing dynamic transitive closures or multicast network codings [N. J. A. Harvey, D. R. Karger, and K. Murota, Proceedings of the Sixteenth Annual ACMSIAMSymposium on Discrete Algorithms, 2005, pp. 489-498; N. J. A. Harvey, D. R. Karger, and S. Yekhanin, Proceedings of the Seventeenth Annual ACM-SIAM Symposium on Discrete Algorithms, 2006, pp. 1103-1111]. We design efficient deterministic algorithms for common generalizations of the results of Lovász and Geelen on this problem by allowing linear polynomials in the entries of the input matrix such that the submatrices corresponding to each variable have rank one. Our methods are algebraic and quite different from those of Lovász and Geelen. We look at the problem of matrix completion in the more general setting of linear spaces of linear transformations and find a maximum rank element there using a greedy method. Matrix algebras and modules play a crucial role in the algorithm. We show (hardness) results for special instances of matrix completion naturally related to matrix algebras; i.e., in contrast to computing isomorphisms of modules (for which there is a known deterministic polynomial time algorithm), finding a surjective or an injective homomorphism between two given modules is as hard as the general matrix completion problem. The same hardness holds for finding a maximum dimension cyclic submodule (i.e., generated by a single element). For the "dual" task, i.e., finding the minimal number of generators of a given module, we present a deterministic polynomial time algorithm. The proof methods developed in this paper apply to fairly general modules and could also be of independent interest. © 2010 Society for Industrial and Applied Mathematics.

Kontschan J.,Hungarian Academy of Sciences
Zootaxa | Year: 2011

A new monotypic genus Editella thailandica gen. nov., sp. nov., is described on the basis of one female and two males collected in Thailand. The new genus is unusual among Uropodina by the presence of an internal sclerotised node associated with the levator tendon in large, strongly dentate chelicerae. Taxonomic notes on the genus Hutufeideria are presented and three new species are described (Hutufeideria thailandica sp. nov., Hutufeideria phuketensis sp. nov., Hutufeideria alata sp. nov.). The name of the Australian species Hutufeideria hirschmanni (Hiramatsu, 1978) is a homonym of Hutufeideria hirschmanni Hiramatsu, 1978, from New Guinean, hence Hutufeideria hirschmannoides nom. nov. is proposed as a replacement name for the Australian species. Copyright © 2011 • Magnolia Press.

Manczinger M.,University of Szeged | Kemeny L.,University of Szeged | Kemeny L.,Hungarian Academy of Sciences
PLoS ONE | Year: 2013

Psoriasis is a multifactorial inflammatory skin disease characterized by increased proliferation of keratinocytes, activation of immune cells and susceptibility to metabolic syndrome. Systems biology approach makes it possible to reveal novel important factors in the pathogenesis of the disease. Protein-protein, protein-DNA, merged (containing both protein-protein and protein-DNA interactions) and chemical-protein interaction networks were constructed consisting of differentially expressed genes (DEG) between lesional and non-lesional skin samples of psoriatic patients and/or the encoded proteins. DEGs were determined by microarray meta-analysis using MetaOMICS package. We used STRING for protein-protein, CisRED for protein-DNA and STITCH for chemical-protein interaction network construction. General network-, cluster- and motif-analysis were carried out in each network. Many DEG-coded proteins (CCNA2, FYN, PIK3R1, CTGF, F3) and transcription factors (AR, TFDP1, MEF2A, MECOM) were identified as central nodes, suggesting their potential role in psoriasis pathogenesis. CCNA2, TFDP1 and MECOM might play role in the hyperproliferation of keratinocytes, whereas FYN may be involved in the disturbed immunity in psoriasis. AR can be an important link between inflammation and insulin resistance, while MEF2A has role in insulin signaling. A controller sub-network was constructed from interlinked positive feedback loops that with the capability to maintain psoriatic lesional phenotype. Analysis of chemical-protein interaction networks detected 34 drugs with previously confirmed disease-modifying effects, 23 drugs with some experimental evidences, and 21 drugs with case reports suggesting their positive or negative effects. In addition, 99 unpublished drug candidates were also found, that might serve future treatments for psoriasis. © 2013 Manczinger, Kemény.

Mayer I.,Hungarian Academy of Sciences
Molecular Physics | Year: 2010

Löwdin's pairing theorem and its extension by Karadakov are briefly overviewed and some less usual applications (outside the original realm of the spin-projected theories) are discussed. These are pertinent to the theory of intermolecular interactions and to the construction of extremely localized, but non-orthogonal, molecular orbitals. © 2010 Taylor & Francis.

Farkas A.,Hungarian Academy of Sciences | Szoke I.,Institute for Energy Technology of Norway
Inhalation Toxicology | Year: 2013

For a correct assessment of health consequences of inhaled aerosols as a function of dose, whether for environmental, occupational or therapeutic agents, knowledge of their deposition distribution in the respiratory tract and subsequent clearance is important. The objective of this study is to model particle clearance at bronchial airway bifurcation level and to analyze the combined effect of deposition and clearance. For this purpose, a numerical model has been implemented. Air and mucus flow fields were computed in a model bronchial airway bifurcation. Inhaled particles with 1 and 10μm aerodynamic diameters were tracked to determine deposition and clearance patterns. Simulation results revealed the existence of a slow clearance zone around the peak of the airway bifurcation causing delayed clearance of the particles depositing or entering here. Particles clearing up from the deeper airways and crossing the studied bifurcation do not accumulate in this zone, because of their tendency to avoid it. The average residence time of these particles was around 20min independently of particle size (whether it is 1 or 10μm). However, as a result of the superposition of deposition and clearance mechanisms, the final spatial distribution of particles deposited primarily in the target bifurcation is size dependent, because deposition is size specific. Although deposition density of particles deposited in the slow clearance area is one-two orders of magnitude higher than the average deposition density, these values are reduced by clearance by the factors of 4-7, depending on the particle size and the surface area of the selected slow clearance zone. In conclusion, although particle deposition is inhomogeneous, clearance can significantly decrease the degree of spatial non-uniformity of the particles. Therefore, for a correct assessment of doses at local levels, it is important to consider both deposition and clearance. Although future research may overwrite some of the model assumptions on the nature of mucus, the authors think that most of the current predictions will hold. © 2013 Informa Healthcare USA, Inc. All rights reserved.

The Villány area, as a central part of the Tisza microcontinent/terrane along the European margin of Tethys, was characterized by intense subsidence in the Early and Middle Triassic, followed by a long interruption of subsidence in the Late Triassic to Middle Jurassic. During the Middle-Late Jurassic transition, marine sedimentation started with three distinct sedimentary episodes dated as Late Bathonian, Early Callovian, and Middle-Late Callovian, respectively. The succession is terminated by a thick limestone of Middle Oxfordian age. The sedimentary features, microfacies, and macroinvertebrate associations of these four stratigraphic units are documented and illustrated. The Middle to Late Jurassic sedimentary episodes of the Villány succession record an interplay of local and global factors and paleogeographical changes. At the beginning, local tectonic movements governed the main features of sedimentation, though the role of eustasy was also essential. From the mid-Callovian onwards, global climatic, biotic, and paleoceanographical changes controlled the nature and formation of the local carbonate sediments. The Callovian stromatolites are attributed to the activity of sulphate-reducing bacteria in a deep sublittoral, current-swept environment. Upwelling of eutrophic Tethyan waters is recorded by the prevalence of the Bositra filament microfacies in the Callovian. The long submarine hiatus at around the Callovian-Oxfordian transition mirrors a serious restriction of the carbonate budget, due to sudden cooling and a change in the oceanic current system (opening of a circumglobal Tethyan Passage), and to a higher amount of dissolved CO2. In the Middle Oxfordian, the carbonate production considerably increased in accordance with the sudden global warming. © 2011 Springer-Verlag.

Wippermann S.,University of California at Davis | Voros M.,Budapest University of Technology and Economics | Rocca D.,University of California at Davis | Gali A.,Budapest University of Technology and Economics | And 3 more authors.
Physical Review Letters | Year: 2013

We present density functional and many body perturbation theory calculations of the electronic, optical, and impact ionization properties of Si nanoparticles (NPs) with core structures based on high-pressure bulk Si phases. Si particles with a BC8 core structure exhibit significantly lower optical gaps and multiple exciton generation (MEG) thresholds, and an order of magnitude higher MEG rate than diamondlike ones of the same size. Several mechanisms are discussed to further reduce the gap, including surface reconstruction and chemistry, excitonic effects, and embedding pressure. Experiments reported the formation of BC8 NPs embedded in amorphous Si and in amorphous regions of femtosecond-laser doped "black silicon." For all these reasons, BC8 nanoparticles may be promising candidates for MEG-based solar energy conversion. © 2013 American Physical Society.

Grohe M.,Humboldt University of Berlin | Marx D.,Hungarian Academy of Sciences
Proceedings of the Annual ACM Symposium on Theory of Computing | Year: 2012

We generalize the structure theorem of Robertson and Seymour for graphs excluding a fixed graph H as a minor to graphs excluding H as a topological subgraph. We prove that for a fixed H, every graph excluding H as a topological subgraph has a tree decomposition where each part is either "almost embeddable" to a fixed surface or has bounded degree with the exception of a bounded number of vertices. Furthermore, such a decomposition is computable by an algorithm that is fixed-parameter tractable with parameter |H|. We present two algorithmic applications of our structure theorem. To illustrate the mechanics of a "typical" application of the structure theorem, we show that on graphs excluding H as a topological subgraph, Partial Dominating Set (find k vertices whose closed neighborhood has maximum size) can be solved in time f(H,k)·n O(1) time. More significantly, we show that on graphs excluding H as a topological subgraph, Graph Isomorphism can be solved in time n f(H). This result unifies and generalizes two previously known important polynomial-time solvable cases of Graph Isomorphism: bounded-degree graphs and H-minor free graphs. The proof of this result needs a generalization of our structure theorem to the context of invariant treelike decomposition. © 2012 ACM.

Galilean invariance leaves its imprint on the energy spectrum and eigenstates of N quantum particles, bosons, or fermions, confined in a bounded domain. It endows the spectrum with a recurrent structure, which in capillaries or elongated traps of length L and cross-section area s leads to spectral gaps n2h2sρ/(2mL) at wave numbers 2nπsρ, where ρ is the number density and m is the particle mass. In zero temperature superfluids, in toroidal geometries, it causes the quantization of the flow velocity with the quantum h/(mL) or that of the circulation along the toroid with the known quantum h/m. Adding a "friction" potential, which breaks Galilean invariance, the Hamiltonian can have a superfluid ground state at low flow velocities but not above a critical velocity, which may be different from the velocity of sound. In the limit of infinite N and L, if N/L=sρ is kept fixed, translation invariance is broken, and the center of mass has a periodic distribution, while superfluidity persists at low flow velocities. This conclusion holds for the Lieb-Liniger model. © 2014 American Physical Society.

Quintino M.T.,University of Geneva | Vertesi T.,Hungarian Academy of Sciences | Brunner N.,University of Geneva
Physical Review Letters | Year: 2014

We investigate the relation between the incompatibility of quantum measurements and quantum nonlocality. We show that a set of measurements is not jointly measurable (i.e., incompatible) if and only if it can be used for demonstrating Einstein-Podolsky-Rosen steering, a form of quantum nonlocality. Moreover, we discuss the connection between Bell nonlocality and joint measurability, and give evidence that both notions are inequivalent. Specifically, we exhibit a set of incompatible quantum measurements and show that it does not violate a large class of Bell inequalities. This suggests the existence of incompatible quantum measurements which are Bell local, similarly to certain entangled states which admit a local hidden variable model. © 2014 American Physical Society.

Vitagliano G.,University of the Basque Country | Hyllus P.,University of the Basque Country | Egusquiza I.L.,University of the Basque Country | Toth G.,University of the Basque Country | And 2 more authors.
Physical Review Letters | Year: 2011

We determine the complete set of generalized spin squeezing inequalities, given in terms of the collective angular momentum components, for particles with an arbitrary spin. They can be used for the experimental detection of entanglement in an ensemble in which the particles cannot be individually addressed. We also present a large set of criteria involving collective observables different from the angular momentum coordinates. We show that some of the inequalities can be used to detect k-particle entanglement and bound entanglement. © 2011 American Physical Society.

Bowles J.,University of Geneva | Vertesi T.,Hungarian Academy of Sciences | Quintino M.T.,University of Geneva | Brunner N.,University of Geneva | Brunner N.,University of Bristol
Physical Review Letters | Year: 2014

Einstein-Podolsky-Rosen steering is a form of quantum nonlocality exhibiting an inherent asymmetry between the observers, Alice and Bob. A natural question is then whether there exist entangled states which are one-way steerable, that is, Alice can steer Bob's state, but it is impossible for Bob to steer the state of Alice. So far, such a phenomenon has been demonstrated for continuous variable systems, but with a strong restriction on allowed measurements, namely, considering only Gaussian measurements. Here we present a simple class of entangled two-qubit states which are one-way steerable, considering arbitrary projective measurements. This shows that the nonlocal properties of entangled states can be fundamentally asymmetrical. © 2014 American Physical Society.

Gyorgy A.,Hungarian Academy of Sciences | Kocsis L.,Computer and Automation Research Institute
Journal of Artificial Intelligence Research | Year: 2011

Local search algorithms applied to optimization problems often suffer from getting trapped in a local optimum. The common solution for this deficiency is to restart the algorithm when no progress is observed. Alternatively, one can start multiple instances of a local search algorithm, and allocate computational resources (in particular, processing time) to the instances depending on their behavior. Hence, a multi-start strategy has to decide (dynamically) when to allocate additional resources to a particular instance and when to start new instances. In this paper we propose multi-start strategies motivated by works on multi-armed bandit problems and Lipschitz optimization with an unknown constant. The strategies continuously estimate the potential performance of each algorithm instance by supposing a convergence rate of the local search algorithm up to an unknown constant, and in every phase allocate resources to those instances that could converge to the optimum for a particular range of the constant. Asymptotic bounds are given on the performance of the strategies. In particular, we prove that at most a quadratic increase in the number of times the target function is evaluated is needed to achieve the performance of a local search algorithm started from the attraction region of the optimum. Experiments are provided using SPSA (Simultaneous Perturbation Stochastic Approximation) and kmeans as local search algorithms, and the results indicate that the proposed strategies work well in practice, and, in all cases studied, need only logarithmically more evaluations of the target function as opposed to the theoretically suggested quadratic increase. © 2011 AI Access Foundation. All rights reserved.

Yang T.H.,National University of Singapore | Vertesi T.,Hungarian Academy of Sciences | Bancal J.-D.,National University of Singapore | Scarani V.,National University of Singapore | Navascues M.,University of Bristol
Physical Review Letters | Year: 2014

Self-testing refers to the fact that, in some quantum devices, both states and measurements can be assessed in a black-box scenario, on the sole basis of the observed statistics, i.e., without reference to any prior device calibration. Only a few examples of self-testing are known, and they just provide nontrivial assessment for devices performing unrealistically close to the ideal case. We overcome these difficulties by approaching self-testing with the semidefinite programing hierarchy for the characterization of quantum correlations. This allows us to improve dramatically the robustness of previous self-testing schemes; e.g., we show that a Clauser-Horne-Shimony-Holt violation larger than 2.57 certifies a singlet fidelity of more than 70%. In addition, the versatility of the tool brings about self-testing of hitherto impossible cases, such as the robust self-testing of nonmaximally entangled two-qutrit states in the Collins-Gisin-Linden-Massar-Popescu scenario. © 2014 American Physical Society.

Edge J.M.,KTH Royal Institute of Technology | Asboth J.K.,Hungarian Academy of Sciences
Physical Review B - Condensed Matter and Materials Physics | Year: 2015

We investigate time-independent disorder on several two-dimensional discrete-time quantum walks. We find numerically that, contrary to claims in the literature, random onsite phase disorder, spin-dependent or otherwise, cannot localize the Hadamard quantum walk; rather, it induces diffusive spreading of the walker. In contrast, split-step quantum walks are generically localized by phase disorder. We explain this difference by showing that the Hadamard walk is a special case of the split-step quantum walk, with parameters tuned to a critical point at a topological phase transition. We show that the topological phase transition can also be reached by introducing strong disorder in the rotation angles. We determine the critical exponent for the divergence of the localization length at the topological phase transition, and find ν=2.6, in both cases. This places the two-dimensional split-step quantum walk in the universality class of the quantum Hall effect. © 2015 American Physical Society.

Burston J.J.,University of Nottingham | Woodhams S.G.,Hungarian Academy of Sciences
Proceedings of the Nutrition Society | Year: 2014

The endocannabinoid (EC) system consists of two main receptors: cannabinoid type 1 receptor cannabinoid receptors are found in both the central nervous system (CNS) and periphery, whereas the cannabinoid type 2 receptor cannabinoid receptor is found principally in the immune system and to a lesser extent in the CNS. The EC family consists of two classes of well characterised ligands; the N-acyl ethanolamines, such as N-arachidonoyl ethanolamide or anandamide (AEA), and the monoacylglycerols, such as 2-arachidonoyl glycerol. The various synthetic and catabolic pathways for these enzymes have been (with the exception of AEA synthesis) elucidated. To date, much work has examined the role of EC in nociceptive processing and the potential of targeting the EC system to produce analgesia. Cannabinoid receptors and ligands are found at almost every level of the pain pathway from peripheral sites, such as peripheral nerves and immune cells, to central integration sites such as the spinal cord, and higher brain regions such as the periaqueductal grey and the rostral ventrolateral medulla associated with descending control of pain. EC have been shown to induce analgesia in preclinical models of acute nociception and chronic pain states. The purpose of this review is to critically evaluate the evidence for the role of EC in the pain pathway and the therapeutic potential of EC to produce analgesia. We also review the present clinical work conducted with EC, and examine whether targeting the EC system might offer a novel target for analgesics, and also potentially disease-modifying interventions for pathophysiological pain states. Copyright © The Authors 2013.

Glanzel W.,Catholic University of Leuven | Glanzel W.,Hungarian Academy of Sciences
Journal of Informetrics | Year: 2010

In the present paper we give an overview over the opportunities of probabilistic models in scientometrics. Four examples from different topics are used to shed light on some important aspects of reliability and robustness of indicators based on stochastic models. Limitations and future tasks are discussed as well. © 2010 Elsevier Ltd.

Meszaros C.,Hungarian Academy of Sciences
Optimization Methods and Software | Year: 2010

Computers with CPUs of multiple computing cores are now widely available. In the paper, we investigate how these modern architectures perform in the practice of interior point methods. In our study, we shall focus on the implementation of the Cholesky factorization of large-scale and sparse symmetric positive semidefinite matrices. Our numerical experiments will demonstrate that capabilities of modern processors can be efficiently utilized by special implementation techniques.

Heder M.,Hungarian Academy of Sciences
ICIC Express Letters | Year: 2011

The current interfaces of online knowledge production systems are not optimal for the creation of high-quality knowledge units. This study investigates possible methods for the integration of AI solutions into those web interfaces where users produce knowledge, e.g., Wikipedia, forums and blogs. A requirement survey was conducted in order to predict which solutions the users would most likely accept out of the many possible choices. We focused on the reading and editing preferences of Wikipedia users, Wikipedia being the biggest knowledge production and sharing framework. We found that many functions can be easily implemented into the knowledge production interface if we simply integrate well-known and available AI solutions. The results of our survey show that right now the need for basic, but well-implemented and integrated AI functions is greater than the need for cutting-edge, complex AI modules. It can be concluded that even if it is advisable to constantly improve the underlying algorithms and methods of the system, much more emphasis should be given to the interface design of currently available AI solutions. © 2011 ICIC International.

Elek G.,Hungarian Academy of Sciences
Random Structures and Algorithms | Year: 2010

Parameter testing algorithms are using constant number of queries to estimate the value of a certain parameter of a very large finite graph. It is well-known that graph parameters such as the independence ratio or the edit-distance from 3-colorability are not testable in bounded degree graphs. We prove, however, that these and several other interesting graph parameters are testable in bounded degree graphs of subexponential growth. © 2010 Wiley Periodicals, Inc.

Odor G.,Hungarian Academy of Sciences
EPJ Web of Conferences | Year: 2013

The Contact Process has been studied on complex networks exhibiting different kinds of quenched disorder. Numerical evidence is found for Griffiths phases and other rare region effects, in Erdos Rényi networks, leading rather generically to anomalously slow (algebraic, logarithmic,...) relaxation. More surprisingly, it turns out that Griffiths phases can also emerge in the absence of quenched disorder, as a consequence of sole topological heterogeneity in networks with finite topological dimension. In case of scalefree networks, exhibiting infinite topological dimension, slow dynamics can be observed on tree-like structures and a superimposed weight pattern. In the infinite size limit the correlated subspaces of vertices seem to cause a smeared phase transition. These results have a broad spectrum of implications for propagation phenomena and other dynamical process on networks and are relevant for the analysis of both models and empirical data. © 2013 Owned by the authors, published by EDP Sciences.

Turu G.,Semmelweis University | Hunyady L.,Semmelweis University | Hunyady L.,Hungarian Academy of Sciences
Journal of Molecular Endocrinology | Year: 2010

The CB1 cannabinoid receptor (CB1R) is the major cannabinoid receptor in neuronal cells and the brain, but it also occurs in endocrine cells and other peripheral tissues. CB1R is a member of the superfamily of G-protein-coupled receptors (GPCRs), which are characterized by seven transmembrane helices. The major mediators of CB1R are the G proteins of the Gi/o family, which inhibit adenylyl cyclases in most tissues and cells, and regulate ion channels, including calcium and potassium ion channels. Regulation of ion channels is an important component of neurotransmission modulation by endogenous cannabinoid compounds released in response to depolarization and Ca2+-mobilizing hormones. However, evidence exists that CB1Rs can also stimulate adenylyl cyclase via Gs, induce receptor-mediated Ca2+ fluxes and stimulate phospholipases in some experimental models. Stimulation of CB1R also leads to phosphorylation and activation of mitogen-activated protein kinases (MAPK), such as p42/p44 MAPK, p38 MAPK and c-Jun N-terminal kinase, which can regulate nuclear transcription factors. Activated and phosphorylated CB 1Rs also associate with β-arrestin molecules, which can induce the formation of signalling complexes and participate in the regulation of GPCR signalling. Recent data also suggest that CB1Rs can form homo- and heterodimers/oligomers, and the altered pharmacological properties of these receptor complexes may explain the pharmacological differences observed in various tissues. © 2010 Society for Endocrinology.

Bai P.,Debrecen University | Bai P.,Hungarian Academy of Sciences | Canto C.,Nestle
Cell Metabolism | Year: 2012

While originally described as DNA damage repair agents, recent data suggest a role for poly(ADP-ribose) polymerase (PARP) enzymes in metabolic regulation by influencing mitochondrial function and oxidative metabolism. Here we review how PARP activity has a major metabolic impact and the role of PARP-1 and PARP-2 in diverse metabolic complications. © 2012 Elsevier Inc.

Egedy T.,Hungarian Academy of Sciences
Hungarian Geographical Bulletin | Year: 2012

In recent years it has become apparent that the global crisis aff ects not only the core economic zones, but it also put pressure on individual nation-states to rethink their economic policies. The recession has brought about great waves of transformation especially in the European Union. The case of Greece, Italy, Ireland and Spain shows that the future of the political and economic union and the euro zone may greatly depend on proper local management of the crisis. Smaller countries with open economy like Hungary face particularly diffi cult situation in Europe, therefore, they should elaborate tailored policies to cope with the consequences of global economic crisis. This paper fi rst briefl y outlines the causes of global economic crisis, then it focuses on the most important socio-economic outcomes in Hungary. The paper pays special att ention to the changes having taken place in the national economy, the labour market and their eff ects on the situation of households.

Fekete Z.,Albert Ludwigs University of Freiburg | Fekete Z.,Hungarian Academy of Sciences
Sensors and Actuators, B: Chemical | Year: 2015

Abstract Developments in neurotechnology are recently driven by newly national and international brain research initiatives worldwide. The challenging goal of understanding how the human brain works requires a vast amount of information gained by neural sensors. Microelectrodes implanted in the central nervous system are extensively used to record electric activity inside the brain tissue. More recently, deep-brain stimulation in Parkinson disease proved the feasibility of such electrodes in human medical treatments as well. To add novel sensor or even actuator functions to these microelectrodes, limitations of recent fabrication technologies have to be considered. To date, silicon microtechnology offered the highest potential to meet the demands of neural applications regarding multiple functions integrated on a single implantable microsystem. Besides reproducibility and low variability of silicon-based microelectrodes, combination of various functionalities like standard electrophysiology, integrated signal processing, local drug delivery, neurochemical detection and optogenetic stimulation is also possible using these microsystems. This ability makes silicon microelectrodes good candidates to provide high-resolution recording and stimulation in the electric, fluidic, chemical or optical domain in more complex neurophysiological experiments in the future. The aim of this review is to give an overview on various aspects of silicon-based implantable neural microelectrodes and microsystems developed in the last decade. Microfabrication approaches of 2-D and 3-D arrays are summarized. Features of the latest active microelectrodes including CMOS signal processing circuitry are compared. Integration methods of convection enhanced drug delivery functions for local administration of pharmacons are demonstrated. Performance of recent silicon-based chemical sensors for the detection of neurotransmitters is also studied. An analysis on the latest developments in silicon-based optrodes for optogenetic and thermogenetic stimulation is also included in this paper. Microelectrode-tissue interaction is described through the evaluation of recent experimental studies on in vitro and in vivo biocompatibility. © 2015 Elsevier B.V. All rights reserved.

Gal P.,Hungarian Academy of Sciences
Advances in experimental medicine and biology | Year: 2013

Proteases play important roles in human physiology and pathology. The complement system is a proteolytic cascade, where serine proteases activate each other by limited proteolysis in a strictly ordered manner. Serine proteases are essential in both the initiation and the amplification of the cascade. Since uncontrolled complement activation contributes to the development of serious disease conditions, inhibition of the complement serine proteases could be an attractive therapeutic approach. In this chapter, we give a brief overview of the major types of natural serine protease inhibitors and their role in controlling the complement cascade. A special emphasis is laid on C1-inhibitor, a natural complement protease inhibitor, which is approved for clinical use in hereditary angioedema (HAE). We also examine the potential of developing artificial complement protease inhibitors. Synthetic small-molecule drugs can be very efficient serine protease inhibitors, but they usually lack sufficient specificity. A promising approach to yield more specific compounds is the alteration of natural protease inhibitors through engineering or directed evolution resulting in new variants with fine-tuned specificity and enhanced affinity.

Laszlo J.,Hungarian Academy of Sciences | Kutasi J.,Albitech Ltd
Bioelectromagnetics | Year: 2010

The viability of the microbes Saccharomyces cerevisiae, Bacillus circulans, Escherichia coli, Micrococcus luteus, Pseudomonas fluorescens, Salmonella enteritidis, Serratia marcescens, and Staphylococcus aureus was tested under static magnetic field exposure up to 24 h in either a homogeneous (159.2 ± 13.4 mT) or three types of inhomogeneous static magnetic fields: (i) peak-topeak magnetic flux density 476.7 ±0.1 mT with a lateral magnetic flux density gradient of 47.7 T/m, (ii) 12.0 ±0.1 mT with 1.2 T/m, or (iii) 2.8 ± 0.1 mT with 0.3 T/m. Even the longest period of exposure failed to produce any effect in the growth of bacteriae that could be correlated with static magnetic field exposure. © 2009 Wiley-Liss, Inc.

Kulcsar B.,Budapest University of Technology and Economics | Bokor J.,Hungarian Academy of Sciences | Shinar J.,Technion - Israel Institute of Technology
International Journal of Robust and Nonlinear Control | Year: 2010

Detection and invariant subspaces of unknown inputs' signals for linear parameter-varying systems are examined in the paper. For a class of nonlinear system like this, the effect of unmeasured signals in parameter-varying measurement equation at the plant output is investigated. The main contributions of the paper are the parameter-varying extension of the pseudo-actuation of the possible and generic unknown sensor signal and the proposition of parameter-dependent similarity transformation. The general parameter-varying measurement equation is casted into a parameter-independent form by the similarity transformation, if any. Moreover, it showed that the nonlinear state transformation does not modify the output subspace spanned by the equivalent pseudo-actuator directions. The proposed methods are illustrated by a numerical example. © 2009 John Wiley & Sons, Ltd.

Szilagyi A.,Hungarian Academy of Sciences | Zhang Y.,University of Michigan
Current Opinion in Structural Biology | Year: 2014

The structure of protein-protein complexes can be constructed by using the known structure of other protein complexes as a template. The complex structure templates are generally detected either by homology-based sequence alignments or, given the structure of monomer components, by structure-based comparisons. Critical improvements have been made in recent years by utilizing interface recognition and by recombining monomer and complex template libraries. Encouraging progress has also been witnessed in genome-wide applications of template-based modeling, with modeling accuracy comparable to high-throughput experimental data. Nevertheless, bottlenecks exist due to the incompleteness of the protein-protein complex structure library and the lack of methods for distant homologous template identification and full-length complex structure refinement. © 2013.

Odor G.,Hungarian Academy of Sciences
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

Bursty dynamics of agents is shown to appear at criticality or in extended Griffiths phases, even in case of Poisson processes. I provide numerical evidence for a power-law type of intercommunication time distributions by simulating the contact process and the susceptible-infected-susceptible model. This observation suggests that in the case of nonstationary bursty systems, the observed non-Poissonian behavior can emerge as a consequence of an underlying hidden Poissonian network process, which is either critical or exhibits strong rare-region effects. On the contrary, in time-varying networks, rare-region effects do not cause deviation from the mean-field behavior, and heterogeneity-induced burstyness is absent. © 2014 American Physical Society.

Sos T.,Hungarian Academy of Sciences
Pure and Applied Chemistry | Year: 2011

After a short introduction to place our work in a proper context, this account summarizes our theoretical and synthetic results in the field of frustrated Lewis pair (FLP) chemistry. © 2011 IUPAC.

Odor G.,Hungarian Academy of Sciences
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

Effects of heterogeneity in the suspected-infected-susceptible model on networks are investigated using quenched mean-field theory. The emergence of localization is described by the distributions of the inverse participation ratio and compared with the rare-region effects appearing in simulations and in the Lifschitz tails. The latter, in the linear approximation, is related to the spectral density of the Laplacian matrix and to the time dependent order parameter. I show that these approximations indicate correctly Griffiths phases both on regular one-dimensional lattices and on small-world networks exhibiting purely topological disorder. I discuss the localization transition that occurs on scale-free networks at γ=3 degree exponent. © 2014 American Physical Society.

Vukov J.,Hungarian Academy of Sciences
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

We consider a prisoner's dilemma model where the interaction neighborhood is defined by a square lattice. Players are equipped with basic cognitive abilities such as being able to distinguish their partners, remember their actions, and react to their strategy. By means of their short-term memory, they can remember not only the last action of their partner but the way they reacted to it themselves. This additional accuracy in the memory enables the handling of different interaction patterns in a more appropriate way and this results in a cooperative community with a strikingly high cooperation level for any temptation value. However, the more developed cognitive abilities can only be effective if the copying process of the strategies is accurate enough. The excessive extent of faulty decisions can deal a fatal blow to the possibility of stable cooperative relations. © 2014 American Physical Society.

Monostori L.,Hungarian Academy of Sciences | Monostori L.,Budapest University of Technology and Economics
Procedia CIRP | Year: 2014

One of the most significant directions in the development of computer science and information and communication technologies is represented by Cyber-Physical Systems (CPSs) which are systems of collaborating computational entities which are in intensive connection with the surrounding physical world and its on-going processes, providing and using, at the same time, data-Accessing and data-processing services available on the internet. Cyber-Physical Production Systems (CPPSs), relying on the newest and foreseeable further developments of computer science, information and communication technologies on the one hand, and of manufacturing science and technology, on the other, may lead to the 4th Industrial Revolution, frequently noted as Industry 4.0. The key-note will underline that there are significant roots generally -And particularly in the CIRP community -which point towards CPPSs. Expectations and the related new R&D challenges will be outlined. © 2014 Elsevier B.V. This is an open access article under the CC BY-NC-ND license.

Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor | Mobilia M.,University of Leeds
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

Reciprocity is firmly established as an important mechanism that promotes cooperation. An efficient information exchange is likewise important, especially on structured populations, where interactions between players are limited. Motivated by these two facts, we explore the role of facilitators in social dilemmas on networks. Facilitators are here mirrors to their neighbors - they cooperate with cooperators and defect with defectors - but they do not participate in the exchange of strategies. As such, in addition to introducing direct reciprocity, they also obstruct information exchange. In well-mixed populations, facilitators favor the replacement and invasion of defection by cooperation as long as their number exceeds a critical value. In structured populations, on the other hand, there exists a delicate balance between the benefits of reciprocity and the deterioration of information exchange. Extensive Monte Carlo simulations of social dilemmas on various interaction networks reveal that there exists an optimal interplay between reciprocity and information exchange, which sets in only when a small number of facilitators occupy the main hubs of the scale-free network. The drawbacks of missing cooperative hubs are more than compensated for by reciprocity and, at the same time, the compromised information exchange is routed via the auxiliary hubs with only marginal losses in effectivity. These results indicate that it is not always optimal for the main hubs to become leaders of the masses, but rather to exploit their highly connected state to promote tit-for-tat-like behavior. © 2014 American Physical Society.

Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

Extortion strategies can dominate any opponent in an iterated prisoner's dilemma game. But if players are able to adopt the strategies performing better, extortion becomes widespread and evolutionary unstable. It may sometimes act as a catalyst for the evolution of cooperation, and it can also emerge in interactions between two populations, yet it is not the evolutionarily stable outcome. Here we revisit these results in the realm of spatial games. We find that pairwise imitation and birth-death dynamics return known evolutionary outcomes. Myopic best response strategy updating, on the other hand, reveals counterintuitive solutions. Defectors and extortioners coarsen spontaneously, which allows cooperators to prevail even at prohibitively high temptations to defect. Here extortion strategies play the role of a Trojan horse. They may emerge among defectors by chance, and once they do, cooperators become viable as well. These results are independent of the interaction topology, and they highlight the importance of coarsening, checkerboard ordering, and best response updating in evolutionary games. © 2014 American Physical Society.

Juhasz R.,Hungarian Academy of Sciences
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

We study the distribution of dynamical quantities in various one-dimensional disordered models, the critical behavior of which is described by an infinite randomness fixed point. In the disordered contact process, the survival probability P(t) is found to show multiscaling in the critical point, meaning that P(t)=t-δ, where the (environment and time-dependent) exponent δ has a universal limit distribution when t→. The limit distribution is determined by the strong disorder renormalization group method analytically in the end point of a semi-infinite lattice, where it is found to be exponential, while, in the infinite system, conjectures on its limiting behaviors for small and large δ, which are based on numerical results, are formulated. By the same method, the survival probability in the problem of random walks in random environments is also shown to exhibit multiscaling with an exponential limit distribution. In addition to this, the (imaginary-time) spin-spin autocorrelation function of the random transverse-field Ising chain is found to have a form similar to that of survival probability of the contact process at the level of the renormalization approach. Consequently, a relationship between the corresponding limit distributions in the two problems can be established. Finally, the distribution of the spontaneous magnetization in this model is also discussed. © 2014 American Physical Society.

Kontschan J.,Hungarian Academy of Sciences
Journal of Natural History | Year: 2011

The published records of the already known Macrodinychid species are summarized and a key to the known species of the family is given. New records of the different Macrodinychus species are presented from Saint Lucia, Dominican Republic, Cuba, Costa Rica, Suriname, Fiji, New Guinea, Solomon Islands and Thailand. Two new species (Macrodinychus malayicus sp. nov. and Macrodinychus extremicus sp. nov.) are described and illustrated. The species Macrodinychus paraguayensis Hirschmann, 1975 is proved to be the junior synonym of Macrodinychus parallelepipedus (Berlese, 1916). © 2011 Taylor & Francis.

Mesko B.,Debrecen University | Poliska S.,Debrecen University | Nagy L.,Debrecen University | Nagy L.,Hungarian Academy of Sciences
Trends in Molecular Medicine | Year: 2011

Gene expression profiling in clinical genomics has yet to deliver robust and reliable approaches for developing diagnostics and contributing to personalized medicine. Owing to technological developments and the recent accumulation of expression profiles, it is a timely and relevant question whether peripheral blood gene expression profiling can be used routinely in clinical decision making. Here, we review the available gene expression profiling data of peripheral blood in autoimmune and chronic inflammatory diseases and suggest that peripheral blood mononuclear cells are suitable for descriptive and comparative gene expression analyses. A gene-disease interaction network in chronic inflammatory diseases, a general protocol for future studies and a decision tree for researchers are presented to facilitate standardization and adoption of this approach. © 2010 Elsevier Ltd.

Two new species, Zercon (Zercorientalia) formosianus sp. nov. and Zercon (Zercorientalia) spinosus sp. nov., are de-scribed from the high mountain zone of Taiwan. A new subgenus, Zercon (Zercorientalia) subgen. nov., is established for these species, on the basis of a unique combination of podonotal chaetotaxy and pore positions. Zercon (Zercorientalia) sinensis Petrova & Taskaeva, 1968 is transferred from Zercon (Zercon) Koch, 1836 to the new subgenus. The taxonomic relevance of podonotal chaetotaxy is discussed. © 2011 Magnolia Press.

A new genus Depressorotunda gen. nov. and four new species are described from South-East Asia, namely Depressorotunda malayana sp. nov. and Depressorotunda seticaudata sp. nov. from Malaysia, Depressorotunda thailandica sp. nov. from Thailand and Depressorotunda mirifica sp. nov. from Vietnam. A key to the species of the genus Depressorotunda is provided with 28 original drawings and scanning micrographs. © 2010 Taylor & Francis.

Cygan M.,University of Warsaw | Marx D.,Hungarian Academy of Sciences | Pilipczuk M.,University of Warsaw | Pilipczuk M.,University of Bergen
Proceedings - Annual IEEE Symposium on Foundations of Computer Science, FOCS | Year: 2013

Given a graph G and k pairs of vertices (s1, t1), ... , (sk, tk), the k-Vertex-Disjoint Paths problem asks for pairwise vertex-disjoint paths P1, ... , Pk such that Pi goes from si to ti. Schrijver [SICOMP'94] proved that the k- Vertex-Disjoint Paths problem on planar directed graphs can be solved in time nO(k). We give an algorithm with running time 22 O(k2) · nO(1) for the problem, that is, we show the fixedparameter tractability of the problem. Copyright © 2013 by The Institute of Electrical and Electronics Engineers, Inc.

Varro S.,Hungarian Academy of Sciences
Physica Scripta T | Year: 2010

In the present paper, an example of entanglement between two different kinds of interacting particles, photons and electrons is analysed. The initial-value problem of the Schrödinger equation is solved non-perturbatively for the system of a free electron interacting with a quantized mode of electromagnetic radiation. Wave packets of the dressed states so obtained are constructed in order to describe the spatio-temporal separation of the subsystems before and after interaction. The joint probability amplitudes are calculated for the detection of the electron at some space-time location and the detection of a definite number of photons. The analytical study of the time evolution of entanglement between the initially separated electron wave packet and the radiation mode leads to the conclusion that in general there are non-vanishing entropy remnants in the subsystems after the interaction. On the basis of the simple model to be presented here, the calculated values of the entropy remnants crucially depend on the character of the assumed switching-on and -off of the interaction. © 2010 The Royal Swedish Academy of Sciences.

Szilvasi T.,Budapest University of Technology and Economics | Gali A.,Budapest University of Technology and Economics | Gali A.,Hungarian Academy of Sciences
Journal of Physical Chemistry C | Year: 2014

We systematically study the fluorination of nanometer-sized diamond cages, diamondoids, by time-dependent density functional theory. We find that fluorination affects both the highest occupied and lowest unoccupied molecular orbitals. Partial fluorination may decrease the energy of the excited state, and the lowest unoccupied molecular orbital becomes less exposed to the environment around the fluorinated surface. These new features of fluorinated diamondoids could be very useful in several potential applications of fluorescent nanodiamonds such as nitrogen-vacancy center based sensing at nanoscale. © 2014 American Chemical Society.

Garay J.,Hungarian Academy of Sciences
BioSystems | Year: 2011

I propose a hypothesis on the origin of chiral homogeneity of bio-molecules based on chiral catalysis. The first chiral active centre may have formed on the surface of complexes comprising metal ions, amino acids, other coenzymes and oligomers (short RNAs). The complexes must have been dominated by short RNAs capable of self-reproduction with ligation. Most of the first complexes may have catalysed the production of nucleotides. A basic assumption is that such complexes can be assembled from their components almost freely, in a huge variety of combinations. This assumption implies that " a few" components can constitute " a huge" number of active centre types. Moreover, an experiment is proposed to test the performance of such complexes in vitro.If the complexes were built up freely from their elements, then Darwinian evolution would operate on the assembly mechanism of complexes. For the production of complexes, first their parts had to appear by forming a proper three-dimensional structure. Three possible re-building mechanisms of the proper geometric structure of complexes are proposed. First, the integration of RNA parts of complexes was assisted presumably by a pre-intron. Second, the binding of RNA parts of a complex may give rise to a " polluted" RNA world. Third, the pairing of short RNA parts and their geometric conformation may have been supported by a pre-genetic code.Finally, an evolutionary step-by-step scenario of the origin of homochirality and a " polluted" RNA world is also introduced based on the proposed combinatorial complex chemistry. Homochirality is evolved by Darwinian selection whenever the efficiency of the reflexive autocatalysis of a dynamical combinatorial library increases with the homochirality of the active centres of reactions cascades and the homochirality of the elements of the dynamical combinatorial library. Moreover, the potential importance of phospholipid membrane is also discussed. © 2010 Elsevier Ireland Ltd.

Kereszturi A.,Hungarian Academy of Sciences | Kereszturi A.,The New School
Astrobiology | Year: 2012

The astrobiological significance of certain environment types on Mars strongly depends on the temperature, duration, and chemistry of liquid water that was present there in the past. Recent works have focused on the identification of signs of ancient water on Mars, as it is more difficult to estimate the above-mentioned parameters. In this paper, two important factors are reviewed, the duration and the volume of water at different environment types on past and present Mars. Using currently available information, we can only roughly estimate these values, but as environment types show characteristic differences in this respect, it is worth comparing them and the result may have importance for research in astrobiology. Impact-induced and geothermal hydrothermal systems, lakes, and valley networks were in existence on Mars over the course of from 102 to 106 years, although they would have experienced substantially different temperature regimes. Ancient oceans, as well as water in outflow channels and gullies, and at the microscopic scale as interfacial water layers, would have had inherently different times of duration and overall volume: oceans may have endured from 104 to 10 6 years, while interfacial water would have had the smallest volume and residence time of liquid phase on Mars. Martian wet environments with longer residence times of liquid water are believed to have existed for that amount of time necessary for life to develop on Earth between the Late Heavy Bombardment and the age of the earliest fossil record. The results of this review show the necessity for more detailed analysis of conditions within geothermal heat-induced systems to reconstruct the conditions during weathering and mineral alteration, as well as to search for signs of reoccurring wet periods in ancient crater lakes. © 2012, Mary Ann Liebert, Inc.

Janossy I.,Hungarian Academy of Sciences
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

Magnetic-field-induced surface reorientation of nematic liquid crystals on polyethyl-methacrylate films is studied. The experiments indicate that the time scale of director gliding expands from a fraction of a second to several hours. A power-law distribution function of relaxation times provides very good agreement between measurements and calculated gliding curves. From the model an upper limit of the extrapolation length can be extracted, which points to a surprisingly strong equilibrium azimuthal anchoring of the liquid crystal on the polymer layer. © 2010 The American Physical Society.

Pal A.,Hungarian Academy of Sciences | Pal A.,Eotvos Lorand University
Monthly Notices of the Royal Astronomical Society | Year: 2010

By studying multiple extrasolar planetary systems, it is possible to obtain constraints for planetary masses and orbital inclinations using the detection of mutual perturbations. An analysis of precise radial velocity measurements might reveal these planet-planet interactions and yield a more accurate view of such planetary systems. As in generic data modelling problems, a fit to radial velocity data series has a set of unknown parameters of which parametric derivatives have to be known by both the regression methods and the estimations for the uncertainties. In this paper, an algorithm is described that aids the computation of such derivatives when planetary perturbations are not neglected. The application of the algorithm is demonstrated for the planetary systems of HD 73526, HD 128311 and HD 155358. In addition to the functions related to radial velocity analysis, the actual implementation of the algorithm contains functions that compute spatial coordinates, velocities and barycentric coordinates for each planet. These functions aid the joint analysis of multiple transiting planetary systems, transit timing and/or duration variations or systems where the proper motion of the host star is also measured involving high precision astrometry. The practical implementation related to the above-mentioned problems features functions that make these types of investigation simple and effective. © 2010 The Author. Journal compilation © 2010 RAS.

Csernak E.,Hungarian Academy of Sciences
Applied Immunohistochemistry and Molecular Morphology | Year: 2016

The implementation of targeted therapies revolutionized oncology. As the number of new oncogenic driver mutations, which provide molecular targets for prediction of effective and selective therapies, is increasing, the implementation of fast and reliable methods by molecular pathology labs is very important. Here we report our results with TruSeq Custom Amplicon assay performed on formalin-fixed and paraffin-embedded material. The oligo capture probes targeted the hotspot regions of 10 well-known oncogenes linked to clinical diagnosis and treatment of lung and colorectal adenocarcinomas, melanomas, and gastrointestinal stromal tumors. Fifteen previously genotyped formalin-fixed and paraffin-embedded DNA samples from different tumor types were selected for massively parallel sequencing. A bioinformatics pipeline was developed to identify high-quality variants and remove sequence artifacts. With the exception of 1 sample, which was of lower quality than the others, relevant mutations corresponding to tumor types could be reliable detected by the developed bioinformatical pipeline. This study indicates that the application of TruSeq Custom Amplicon assay is a promising tool in molecular pathology diagnostics, but it is important to standardize sample processing (including fixation, isolation procedure, sample selection based on quality assessment, and rigorous variant calling) to achieve the highest success rate and avoid false results. Copyright 2016 Wolters Kluwer Health, Inc. All rights reserved.

Cserhati T.,Hungarian Academy of Sciences
Biomedical Chromatography | Year: 2010

The newest achievements in the employment of principal component analysis, a multivariate mathematical statistical method, in the evaluation of chromatographic retention data are compiled. The results obtained by various chromatographic technologies such as gas-liquid chromatography, thin-layer chromatography, high-performance liquid chromatography and electrically driven systems are compiled and briefly discussed. Copyright © 2009 John Wiley & Sons, Ltd.

Toth G.,University of the Basque Country | Toth G.,Ikerbasque | Toth G.,Hungarian Academy of Sciences
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We present several entanglement criteria in terms of the quantum Fisher information that help to relate various forms of multipartite entanglement to the sensitivity of phase estimation. We show that genuine multipartite entanglement is necessary to reach the maximum sensitivity in some very general metrological tasks using a two-arm linear interferometer. We also show that it is needed to reach the maximum average sensitivity in a certain combination of such metrological tasks. © 2012 American Physical Society.

Geier J.,Stereo Vision | Hudak M.,Budapest University of Technology and Economics | Hudak M.,Hungarian Academy of Sciences
PLoS ONE | Year: 2011

The Chevreul illusion is a well-known 19 th century brightness illusion, comprising adjacent homogeneous grey bands of different luminance, which are perceived as inhomogeneous. It is generally explained by lateral inhibition, according to which brighter areas projected to the retina inhibit the sensitivity of neighbouring retinal areas. Lateral inhibition has been considered the foundation-stone of early vision for a century, upon which several computational models of brightness perception are built. One of the last strongholds of lateral inhibition is the Chevreul illusion, which is often illustrated even in current textbooks. Here we prove that lateral inhibition is insufficient to explain the Chevreul illusion. For this aim, we placed the Chevreul staircase in a luminance ramp background, which noticeably changed the illusion. In our psychophysical experiments, all 23 observers reported a strong illusion, when the direction of the ramp was identical to that of the staircase, and all reported homogeneous steps (no illusion) when its direction was the opposite. When the background of the staircase was uniform, 14 saw the illusion, and 9 saw no illusion. To see whether the change of the entire background area or that of the staircase boundary edges were more important, we placed another ramp around the staircase, whose direction was opposite to that of the original, larger ramp. The result is that though the inner ramp is rather narrow (mean = 0.51 deg, SD = 0.48 deg, N = 23), it still dominates perception. Since all conditions of the lateral inhibition account were untouched within the staircase, lateral inhibition fails to model these perceptual changes. Area ratios seem insignificant; the role of boundary edges seems crucial. We suggest that long range interactions between boundary edges and areas enclosed by them, such that diffusion-based models describe, provide a much more plausible account for these brightness phenomena, and local models are insufficient. © 2011 Geier, Hudák.

Kiss L.,University of Szeged | Fulop F.,University of Szeged | Fulop F.,Hungarian Academy of Sciences
Synlett | Year: 2010

This report provides an overview of the most important aspects of the syntheses of functionalized cyclic -amino acids in recent years. The presentation focuses in particular on strategies involving the selective functionalization of unsaturated alicyclic -amino acids. The limitations and shortcomings of the synthetic methods are emphasized, and the possible new challenges and developments in this field in the near future are outlined. 1 Introduction 2 Synthesis of Functionalized Cyclic -Amino Acids via C-C Double Bond Transformations of the Cycloalkenes 2.1 Functionalization via Stereoselective Iodooxazination and Iodooxazoline Formation 2.2 Functionalization via Stereoselective Iodolactonization 2.3 Functionalization via Stereoselective Iodolactamization 2.4 Functionalization Involving Stereoselective Epoxidation and Regioselective Oxirane Opening 2.5 Functionalization via Selective Dihydroxylation 2.6 Functionalization via 1,3-Dipolar Cycloaddition 2.7 Other Methods Based on Functionalization of Ring C-C Double Bonds 3 Some Relevant Routes to Functionalized Cyclic -Amino Acids other than Functionalization of Ring C-C Double Bonds 4 Conclusions. © Georg Thieme Verlag Stuttgart New York.

Miklos I.,Renyi Institute | Zadori Z.,Hungarian Academy of Sciences
PLoS Computational Biology | Year: 2012

HD amino acid duplex has been found in the active center of many different enzymes. The dyad plays remarkably different roles in their catalytic processes that usually involve metal coordination. An HD motif is positioned directly on the amyloid beta fragment (Aβ) and on the carboxy-terminal region of the extracellular domain (CAED) of the human amyloid precursor protein (APP) and a taxonomically well defined group of APP orthologues (APPOs). In human Aβ HD is part of a presumed, RGD-like integrin-binding motif RHD; however, neither RHD nor RXD demonstrates reasonable conservation in APPOs. The sequences of CAEDs and the position of the HD are not particularly conserved either, yet we show with a novel statistical method using evolutionary modeling that the presence of HD on CAEDs cannot be the result of neutral evolutionary forces (p&0.0001). The motif is positively selected along the evolutionary process in the majority of APPOs, despite the fact that HD motif is underrepresented in the proteomes of all species of the animal kingdom. Position migration can be explained by high probability occurrence of multiple copies of HD on intermediate sequences, from which only one is kept by selective evolutionary forces, in a similar way as in the case of the "transcription binding site turnover." CAED of all APP orthologues and homologues are predicted to bind metal ions including Amyloid-like protein 1 (APLP1) and Amyloid-like protein 2 (APLP2). Our results suggest that HDs on the CAEDs are most probably key components of metal-binding domains, which facilitate and/or regulate inter- or intra-molecular interactions in a metal ion-dependent or metal ion concentration-dependent manner. The involvement of naturally occurring mutations of HD (Tottori (D7N) and English (H6R) mutations) in early onset Alzheimer's disease gives additional support to our finding that HD has an evolutionary preserved function on APPOs. © 2012 Miklós, Zadori.

Kotakis C.,Hungarian Academy of Sciences
International Journal of Astrobiology | Year: 2016

Genetic inter-communication of the nucleic-organellar dual in eukaryotes is dominated by DNA-directed phenomena. RNA regulatory circuits have also been observed in artificial laboratory prototypes where gene transfer events are reconstructed, but they are excluded from the primary norm due to their rarity. Recent technical advances in organellar biotechnology, genome engineering and single-molecule tracking give novel experimental insights on RNA metabolism not only at cellular level, but also on organismal survival. Here, I put forward a hypothesis for RNA's involvement in gene piece transfer, taken together the current knowledge on the primitive RNA character as a biochemical modulator with model organisms from peculiar natural habitats. It is proposed that RNA molecules of special structural signature and functional identity can drive evolution, integrating the ecological pressure of environmental oscillations into genome imprinting by buffering-out epigenetic aberrancies. © 2015 Cambridge University Press.

Juhasz R.,Hungarian Academy of Sciences
Journal of Statistical Mechanics: Theory and Experiment | Year: 2010

A two-lane exclusion process is studied where particles move in the two lanes in opposite directions and are able to change lanes. The focus is on the steady state behavior in situations where a positive current is constrained to an extended subsystem (either by appropriate boundary conditions or by the embedding environment) where, in the absence of the constraint, the current would be negative. We have found two qualitatively different kinds of steady states and formulated the conditions for them in terms of the transition rates. In the first type of steady state, a localized cluster of particles forms with an anti-shock located in the subsystem and the current vanishes exponentially with the extension of the subsystem. This behavior is analogous to that of the one-lane partially asymmetric simple exclusion process, and can be realized e.g.when the local drive is induced by making the jump rates in two lanes unequal. In the second type of steady state, which is realized e.g.if the local drive is induced purely by the bias in the lane change rates, and which thus has no counterpart in the one-lane model, a delocalized cluster of particles forms which performs a diffusive motion as a whole and, as a consequence, the current vanishes inversely proportionally to the extension of the subsystem. The model is also studied in the presence of quenched disorder, where, in the case of delocalization, phenomenological considerations predict anomalously slow, logarithmic decay of the current with the system size in contrast with the usual power law. © 2010 IOP Publishing Ltd and SISSA.

Batary P.,University of Gottingen | Baldi A.,Hungarian Academy of Sciences | Kleijn D.,Wageningen University | Tscharntke T.,University of Gottingen
Proceedings of the Royal Society B: Biological Sciences | Year: 2011

Agri-environmental management (AEM) is heralded as being key to biodiversity conservation on farmland, yet results of these schemes have been mixed, making their general utility questionable. We test with meta-analysis whether the benefits of AEM for species richness and abundance of plants and animals are determined by the surrounding landscape context. Across all studies (109 observations for species richness and 114 observations for abundance), AEM significantly increased species richness and their abundance. More specifically, we test the hypothesis that AEM benefits species richness and abundance (i.e. increases the difference between fields with and without AEM) more in simple than in complex landscapes. In croplands, species richness but not abundance was significantly enhanced in simple but not in complex landscapes. In grasslands, AEM effectively enhanced species richness and abundance regardless of landscape context. Pollinators were significantly enhanced by AEM in simple but not in complex landscapes in both croplands and grasslands. Our results highlight that the onesize- fits-all approach of many agri-environmental programmes is not an efficient way of spending the limited funds available for biodiversity conservation on farmland. Therefore, we conclude that AEM should be adapted to landscape structure and the species groups at which they are targeted. © 2010 The Royal Society.

Odor G.,Hungarian Academy of Sciences
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

The susceptible-infected-susceptible (SIS) model is one of the simplest memoryless systems for describing information or epidemic spreading phenomena with competing creation and spontaneous annihilation reactions. The effect of quenched disorder on the dynamical behavior has recently been compared to quenched mean-field (QMF) approximations in scale-free networks. QMF can take into account topological heterogeneity and clustering effects of the activity in the steady state by spectral decomposition analysis of the adjacency matrix. Therefore, it can provide predictions on possible rare-region effects, thus on the occurrence of slow dynamics. I compare QMF results of SIS with simulations on various large dimensional graphs. In particular, I show that for Erdos-Rényi graphs this method predicts correctly the occurrence of rare-region effects. It also provides a good estimate for the epidemic threshold in case of percolating graphs. Griffiths Phases emerge if the graph is fragmented or if we apply a strong, exponentially suppressing weighting scheme on the edges. The latter model describes the connection time distributions in the face-to-face experiments. In case of a generalized Barabási-Albert type of network with aging connections, strong rare-region effects and numerical evidence for Griffiths Phase dynamics are shown. The dynamical simulation results agree well with the predictions of the spectral analysis applied for the weighted adjacency matrices. © 2013 American Physical Society.

Asboth J.K.,Hungarian Academy of Sciences | Obuse H.,Hokkaido University
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

Discrete-time quantum walks (DTQW) have topological phases that are richer than those of time-independent lattice Hamiltonians. Even the basic symmetries, on which the standard classification of topological insulators hinges, have not yet been properly defined for quantum walks. We introduce the key tool of time frames, i.e., we describe a DTQW by the ensemble of time-shifted unitary time-step operators belonging to the walk. This gives us a way to consistently define chiral symmetry (CS) for DTQW's. We show that CS can be ensured by using an "inversion symmetric" pulse sequence. For one-dimensional DTQW's with CS, we identify the bulk Z×Z topological invariant that controls the number of topologically protected 0 and π energy edge states at the interfaces between different domains, and give simple formulas for these invariants. We illustrate this bulk-boundary correspondence for DTQW's on the example of the "4-step quantum walk," where tuning CS and particle-hole symmetry realizes edge states in various symmetry classes. © 2013 American Physical Society.

Odor G.,Hungarian Academy of Sciences
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

I extend a previous work to susceptible-infected-susceptible (SIS) models on weighted Barabási-Albert scale-free networks. Numerical evidence is provided that phases with slow, power-law dynamics emerge as the consequence of quenched disorder and tree topologies studied previously with the contact process. I compare simulation results with spectral analysis of the networks and show that the quenched mean-field (QMF) approximation provides a reliable, relatively fast method to explore activity clustering. This suggests that QMF can be used for describing rare-region effects due to network inhomogeneities. Finite-size study of the QMF shows the expected disappearance of the epidemic threshold λc in the thermodynamic limit and an inverse participation ratio ∼0.25, meaning localization in case of disassortative weight scheme. Contrarily, for the multiplicative weights and the unweighted trees, this value vanishes in the thermodynamic limit, suggesting only weak rare-region effects in agreement with the dynamical simulations. Strong corrections to the mean-field behavior in case of disassortative weights explains the concave shape of the order parameter ρ(λ) at the transition point. Application of this method to other models may reveal interesting rare-region effects, Griffiths phases as the consequence of quenched topological heterogeneities. © 2013 American Physical Society.

Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

We study the evolution of cooperation in the spatial public goods game, focusing on the effects that are brought about by the delayed distribution of goods that accumulate in groups due to the continuous investments of cooperators. We find that intermediate delays enhance network reciprocity because of a decelerated invasion of defectors, who are unable to reap the same high short-term benefits as they do in the absence of delayed distribution. Long delays, however, introduce a risk because the large accumulated wealth might fall into the wrong hands. Indeed, as soon as the curvature of a cooperative cluster turns negative, the engulfed defectors can collect the heritage of many generations of cooperators and by doing so start a waning-moon pattern that nullifies the benefits of decelerated invasion. Accidental meeting points of growing cooperative clusters may also act as triggers for the waning-moon effect, thus linking the success of cooperators with their propensity to fail in a rather bizarre way. Our results highlight that "investing in the future" is a good idea only if that future is sufficiently near and not likely to be burdened by inflation. © 2013 American Physical Society.

Furedi Z.,Hungarian Academy of Sciences | Gunderson D.S.,University of Manitoba
Combinatorics Probability and Computing | Year: 2015

We describe the C 2k+1-free graphs on n vertices with maximum number of edges. The extremal graphs are unique for n ∈ {3k-1, 3k, 4k-2, 4k-1}. The value of ex(n, C2k+1) can be read out from the works of Bondy [3], Woodall [14], and Bollobás [1], but here we give a new streamlined proof. The complete determination of the extremal graphs is also new. We obtain that the bound for n 0(C 2k+1) is 4k in the classical theorem of Simonovits, from which the unique extremal graph is the bipartite Turán graph. © 2014 Cambridge University Press.

Tarcsay A.,Discovery Chemistry | Keseru G.M.,Hungarian Academy of Sciences
Journal of Medicinal Chemistry | Year: 2013

In contrast to designed polypharmacology that can result in efficient drugs for complex disorders, unintended drug promiscuity has detrimental contribution to side effects and toxicology. Characterization of promiscuous compounds enhances the understanding of complex interaction patterns and aids the design of compounds with broader selectivity against off-targets that has a major impact on medicinal chemistry outcome. In this Miniperspective we provide insights to the effect of physicochemical parameters on promiscuity. Information collected from recent, large-scale in vitro studies enabled us to discuss the relationships between physicochemical properties and promiscuity in detail. In light of these data, lipophilicity and basic character have the highest influence. On the basis of the accumulated knowledge, we propose the extensive use of pre- and postsynthesis metrics, as well as strict control of physicochemical properties during medicinal chemistry optimizations. © 2013 American Chemical Society.

Kaszabjbaloghia Hirschmann, 1973, distributed in South-America, is characterized by the following combination of characters: reduced marginal shield, posteromarginal setae placed on membranous cuticle on the dorsal idiosoma, linguliform genital shield in females, oval or egg-like genital shield bearing one pair needle-like setae in males, and the characteristic shape of peritremes. In this contribution, I provide short redescriptions of the known species of Kaszabjbaloghia and describe a new species, K. ecuadorica sp. nov., from Ecuador. The new species is similar to K. kaszabi Hirschmann, 1973, but differs from the latter in the ornamentation of genital shield of the female and the number of sternal cavities. Additionally, we transfer K. hirschmanni Hiramatsu, 1978 to Hutufeideria Hirschmann & Hirmatsu, 1977 (as Hutufeideria hirschmanni (Hiramatsu, 1978) comb. nov.) on the basis of the following: setation of dorsal shield, ornamentation of caudal part of the dorsal shield, shape of hypostomal setae, shape of internal malae and setation of the palp. An identification key to the species of Kaszabjbaloghia is also provided. Original illustrations and scanning micrographs are provided for all species. © 2010 Sociedade Brasileira de Zoologia.

A new monotypic genus, Bloszykiella africana gen. nov., sp. nov. (Mesostigmata: Uropodina: Uropodidae) is described on the basis of two females and one deutonymph found in soil samples from Tanzania. The new genus is unusual among Uropodina in having large strongly dentate chelicerae. © 2010 Magnolia Press.

Ujvari Z.,Hungarian Academy of Sciences
Journal of Natural History | Year: 2010

This paper contributes to the knowledge of the family Zerconidae, describing material collected from several locations in Croatia. Seventeen species are listed, four of them (Prozercon martae sp. nov., Zercon danyii sp. nov., Zercon laczii sp. nov. and Zercon lanceolatus sp. nov.) proved to be new to science, a further eight species (Zercon arcuatus Trägårdh, 1931, Zercon athiasi Vincze, 1965, Zercon berlesei Sellnick, 1958, Zercon latissimus Sellnick, 1944, Zercon romagniolus Sellnick, 1944, Zercon storkani Halaškova, 1969, Zercon tematinensis Mašán Fend'a, 2004, Zercon (Zerconella) leitnerae Willmann, 1953) are recorded for the first time from Croatia. © 2010 Taylor & Francis.

Papp L.,Hungarian Academy of Sciences
Acta Zoologica Academiae Scientiarum Hungaricae | Year: 2010

An overview of the family Hesperinidae is given and differentiating morphology is summarised. The morphological differences in male genitalia of some European populations of Hesperinus imbecillus (LOEW) are demonstrated and all the locality data (Europe) are revised. A second European species, Hesperinus graecus sp. n. (Greece) is described. The specimens from the North Caucasus (Krasnaya Polyana) represent a third species, described elsewhere. With 60 original figures + 2 photos.

Kontschan J.,Hungarian Academy of Sciences
Revue Suisse de Zoologie | Year: 2010

Three new species of Uropodina mites from Thailand, Deraiophorus mirabilis sp. n., Deraiophorus thai- landicus sp. n. and Deraiophorus schwendingeri sp. n., are described and illustrated.

Mentes G.,Hungarian Academy of Sciences
Review of Scientific Instruments | Year: 2012

Very stable and reliable instruments with high accuracy are required in field measurements for continuous monitoring local geodynamic processes, such as tectonic movements, ground motions in landslide prone areas, etc. A sensitive borehole wire extensometer with low energy consumption was developed in the Geodetic and Geophysical Research Institute of the Hungarian Academy of Sciences to observe very small vertical movements (in the order of a few millimeters) of the upper layer of the soil due to hydrological, meteorological and biological processes. The newly developed instrument eliminates the disadvantages of the borehole wire extensometers which are presently used. Its sensitivity and stability are much higher than these parameters of the previous instruments. The instrument is able to measure distance variations without instrumental drift in a range of 0-4 mm with a resolution of better than 1 μm. Since the effect of the yearly temperature variations can be easily removed from the extensometric data record, the compensation for the short-periodic (daily) thermal effects on the instrument was of high priority during the design of the instrument. This paper describes the construction and calibration of the extensometer. The extensometer was installed for monitoring vertical ground movements due to hydro-meteorological processes on the high loess wall of the Danube River at Dunaföldvár, Hungary. The efficiency of the temperature compensation of the instrument was investigated in detail on the basis of the measured data series. © 2012 American Institute of Physics.

Toth T.A.,Ecole Polytechnique Federale de Lausanne | Lauchli A.M.,Max Planck Institute For Physik Komplexer Systeme | Mila F.,Ecole Polytechnique Federale de Lausanne | Penc K.,Hungarian Academy of Sciences
Physical Review Letters | Year: 2010

Combining a semiclassical analysis with exact diagonalizations, we show that the ground state of the SU(3) Heisenberg model on the square lattice develops three-sublattice long-range order. This surprising pattern for a bipartite lattice with only nearest-neighbor interactions is shown to be the consequence of a subtle quantum order-by-disorder mechanism. By contrast, thermal fluctuations favor two-sublattice configurations via entropic selection. These results are shown to extend to the cubic lattice, and experimental implications for the Mott-insulating states of three-flavor fermionic atoms in optical lattices are discussed. © 2010 The American Physical Society.

Ujvari Z.,Hungarian Academy of Sciences
International Journal of Acarology | Year: 2011

I elaborate on material collected near the southern border of Central Mexican Plateau, on the volcano Popocatepetl (Mexico). Five new species of zerconid mites, Amerozercon barbatus n. sp., Amerozercon brevicavus n. sp., Zercon mexicanus n. sp., Zercon popocatepetl n. sp. and Zercon quetzalcoatl n. sp. are described and recorded based on material collected near the southern border of the Central Mexican plateau. Additional diagnostic notes on the genus Amerozercon Halaskova, 1969, which was defined earlier on the basis of a single male specimen, are provided. © 2011 Taylor & Francis.

Chen X.,International Institute For Applied Systems Analysis | Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor | Wang L.,Peking University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

Cooperation and defection may be considered to be two extreme responses to a social dilemma. Yet the reality is much less clear-cut. Between the two extremes lies an interval of ambivalent choices, which may be captured theoretically by means of continuous strategies defining the extent of the contributions of each individual player to the common pool. If strategies are chosen from the unit interval, where 0 corresponds to pure defection and 1 corresponds to the maximal contribution, the question is what is the characteristic level of individual investments to the common pool that emerges if the evolution is guided by different benefit functions. Here we consider the steepness and the threshold as two parameters defining an array of generalized benefit functions, and we show that in a structured population there exist intermediate values of both at which the collective contributions are maximal. However, as the cost-to-benefit ratio of cooperation increases, the characteristic threshold decreases while the corresponding steepness increases. Our observations remain valid if more complex sigmoid functions are used, thus reenforcing the importance of carefully adjusted benefits for high levels of public cooperation. © 2012 American Physical Society.

Odor G.,Hungarian Academy of Sciences | Pastor-Satorras R.,Polytechnic University of Catalonia
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

We show that generic, slow dynamics can occur in the contact process on complex networks with a tree-like structure and a superimposed weight pattern, in the absence of additional (nontopological) sources of quenched disorder. The slow dynamics is induced by rare-region effects occurring on correlated subspaces of vertices connected by large weight edges and manifests in the form of a smeared phase transition. We conjecture that more sophisticated network motifs could be able to induce Griffiths phases, as a consequence of purely topological disorder. © 2012 American Physical Society.

Pulawska J.,Research Institute of Horticulture | Willems A.,Ghent University | De Meyer S.E.,Ghent University | Sule S.,Hungarian Academy of Sciences
Systematic and Applied Microbiology | Year: 2012

Five Gram-negative, rod-shaped, non-spore-forming bacteria were isolated from galls on different plant species in Hungary: strain 39/7T from Prunus cerasifera Myrobalan, strain 0 from grapevine var. Ezerjó, strain 7/1 from raspberry var. Findus and in Poland, strain C3.4.1 from Colt rootstock (Prunus avium×Prunus pseudocerasus) and strain CP17.2.2 from Prunus avium. Only one of these isolates, strain 0, is able to cause crown gall on different plant species. On the basis of 16S rRNA gene sequence similarity, the strains cluster together and belong to the genus Rhizobium and their closest relative is Rhizobium radiobacter (99.1%). Phylogenetic analysis of the novel strains using housekeeping genes atpD, glnA, gyrB, recA and rpoB revealed their distinct position separate from other known Rhizobium species and confirmed their relation to Rhizobium radiobacter. The major cellular fatty acids are 18:1 w7c, 16:0, 16:0 3OH, summed feature 2 (comprising 12:0 aldehyde, 16:1 iso I and/or 14:0 3OH) and summed feature 3 (comprising 16:1 w7c and/or 15 iso 2OH). DNA-DNA hybridization of strain 39/7T with the type strain of R. radiobacter LMG 140T revealed 45% DNA-DNA hybridization. Phenotypic and physiological properties differentiate the novel isolates from other closely related species.On the basis of the results obtained, the five isolates are considered to represent a novel species of the genus Rhizobium, for which the name Rhizobium nepotum sp. nov. (type strain 39/7T=LMG 26435T=CFBP 7436T) is proposed. © 2012 Elsevier GmbH.

Stannett M.,University of Sheffield | Nemeti I.,Hungarian Academy of Sciences
Journal of Automated Reasoning | Year: 2014

Logicians at the Rényi Mathematical Institute in Budapest have spent several years developing versions of relativity theory (special, general, and other variants) based wholly on first-order logic, and have argued in favour of the physical decidability, via exploitation of cosmological phenomena, of formally unsolvable questions such as the Halting Problem and the consistency of set theory. As part of a joint project, researchers at Sheffield have recently started generating rigorous machine-verified versions of the Hungarian proofs, so as to demonstrate the soundness of their work. In this paper, we explain the background to the project and demonstrate a first-order proof in Isabelle/HOL of the theorem "no inertial observer can travel faster than light". This approach to physical theories and physical computability has several pay-offs, because the precision with which physical theories need to be formalised within automated proof systems forces us to recognise subtly hidden assumptions. © 2013 Springer Science+Business Media Dordrecht.

Gali A.,Hungarian Academy of Sciences | Gali A.,Budapest University of Technology and Economics
Physica Status Solidi (B) Basic Research | Year: 2011

A common fingerprint of the electrically active point defects in semiconductors is the transition between their localized defect states upon excitation, which may result in characteristic absorption or photoluminescence spectrum. While density functional calculations have been very successful in exploring the ground-state properties like formation energies or hyperfine tensors the density functional theory (DFT), in principle, is not capable of providing reliable excitation spectrum. Time-dependent (TD)-DFT, however, addresses this issue which makes possible to study the properties of point defects associated with their excited states. In this paper, we apply the TD-DFT on two characteristic examples: the well-known nitrogen-vacancy defect in diamond and the less known divacancy in silicon carbide. The former defect is a leading candidate in solid state quantum bit applications where detailed knowledge about the excitation spectrum is extremely important. The excitation property of divacancy will be also studied and its relevance in different applications will be discussed. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Riesz F.,Hungarian Academy of Sciences
Optics and Laser Technology | Year: 2011

Imaging properties of the Makyoh imaging of periodic and quasi-periodic surfaces are analysed using a spectral approach based on a geometrical optical model. It is shown that in spite of the nonlinear nature of imaging, the Fourier representation can be used with some restrictions and limitations. Ray-tracing simulations are performed to illustrate the results. © 2010 Elsevier Ltd. All rights reserved.

Chen X.,International Institute For Applied Systems Analysis | Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

A collective-risk social dilemma implies that personal endowments will be lost if contributions to the common pool within a group are too small. Failure to reach the collective target thus has dire consequences for all group members, independently of their strategies. Wanting to move away from unfavorable locations is therefore anything but surprising. Inspired by these observations, we here propose and study a collective-risk social dilemma where players are allowed to move if the collective failure becomes too probable. More precisely, this so-called risk-driven migration is launched depending on the difference between the actual contributions and the declared target. Mobility therefore becomes an inherent property that is utilized in an entirely self-organizing manner. We show that under these assumptions cooperation is promoted much more effectively than under the action of manually determined migration rates. For the latter, we in fact identify parameter regions where the evolution of cooperation is greatly inhibited. Moreover, we find unexpected spatial patterns where cooperators that do not form compact clusters outperform those that do, and where defectors are able to utilize strikingly different ways of invasion. The presented results support the recently revealed importance of percolation for the successful evolution of public cooperation, while at the same time revealing surprisingly simple methods of self-organization towards socially desirable states. © 2012 American Physical Society.

Deme A.,Hungarian Academy of Sciences
Journal of Voice | Year: 2014

Background Studies addressing the identification of sung vowels concern mainly the effect of the fundamental frequency (f0) and conclude that correct vowel identification decreases with increasing pitch. In one experiment, the impact of consonantal environment on the intelligibility of the vowels in high-pitched singing was also studied. The results of that experiment showed positive effect of the consonantal environment. This finding is in line with results that had been reported for speech in an earlier study. However, the data on singing are not as transparent as the authors suggest, and there are some conditions in the experiment that could also be controlled for more strictly. Therefore, the effect of the dynamic acoustic information encoded in the formant transitions at high fundamental frequencies is still an open question. Objectives The aim of the present study was to redesign and extend the above-mentioned experiment to test whether the phonetic context and the onset of the vowel uttered in isolation (namely the onset of voicing) have a positive effect on vowel identification. Methods For this purpose, a vowel identification test was carried out. The stimuli included three Hungarian vowels /a:i:u:/ in three conditions (in /bVb/ context, in isolation and with eliminated onset) at seven different fundamental frequencies from 175 to 988 Hz (F3, B3, F4, B4, F5, B5, and speech). The stimuli were produced by one professional soprano singer. Results The results show that consonantal context does not specify vowel identity in singing as clearly as it has been demonstrated for spoken utterances. In addition, no effect of vowel onset (ie, the onset of voicing) was found. Recognition percentages seemed only to be dependent on f0 and vowel quality. Conclusions The unexpected results lend themselves to two possible explanations: the reduction of the consonants and the undersampling of the formant transitions. © 2014 The Voice Foundation.

Juhasz R.,Hungarian Academy of Sciences
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

The problem of random walk is considered in one dimension in the simultaneous presence of a quenched random force field and long-range connections, the probability of which decays with the distance algebraically as p lβl -s. The dynamics are studied mainly by a numerical strong disorder renormalization group method. According to the results, for s>2 the long-range connections are irrelevant, and the mean-square displacement increases as x2(t)∼ (lnt )2 /ψ with the barrier exponent ψ=1/2, which is known in one-dimensional random environments. For s<2, instead, the quenched disorder is found to be irrelevant, and the dynamical exponent is z=1 like in a homogeneous environment. At the critical point, s=2, the interplay between quenched disorder and long-range connections results in activated scaling, however, with a nontrivial barrier exponent ψ(β), which decays continuously with β but is independent of the form of the quenched disorder. Upper and lower bounds on ψ(β) are established, and numerical estimates are given for various values of β. Besides random walks, accurate numerical estimates of the graph dimension and the resistance exponent are given for various values of β at s=2. © 2012 American Physical Society.

Kover L.,Hungarian Academy of Sciences
Surface and Interface Analysis | Year: 2016

Physical and chemical phenomena reflected in electron spectra excited by photons from solids take place on very wide scales of space, time, and excitation energy, covering sometimes differences of many orders of magnitude. Therefore, the use of multiscale approaches seems to be promising when extracting information on electronic structure or chemical composition from such electron spectra. Following a summary of phenomena reflected in electron spectra induced from solids by photons and different type of models available for their interpretation, the challenges of characterization of advanced materials and the need for multiscale materials analysis and modeling will be discussed. © Copyright 2015 John Wiley & Sons, Ltd.

Miklos I.,Renyi Institute | Miklos I.,Hungarian Academy of Sciences | Tannier E.,French Institute for Research in Computer Science and Automation
Bioinformatics | Year: 2010

Motivation: When comparing the organization of two genomes, it is important not to draw conclusions on their modes of evolution from a single most parsimonious scenario explaining their differences. Better estimations can be obtained by sampling many different genomic rearrangement scenarios. For this problem, the Double Cut and Join (DCJ) model, while less relevant, is computationally easier than the Hannenhalli-Pevzner (HP) model. Indeed, in some special cases, the total number of DCJ sorting scenarios can be analytically calculated, and uniformly distributed random DCJ scenarios can be drawn in polynomial running time, while the complexity of counting the number of HP scenarios and sampling from the uniform distribution of their space is unknown, and conjectured to be #P-complete. Statistical methods, like Markov chain Monte Carlo (MCMC) for sampling from the uniform distribution of the most parsimonious or the Bayesian distribution of all possible HP scenarios are required. Results: We use the computational facilities of the DCJ model to draw a sampling of HP scenarios. It is based on a parallel MCMC method that cools down DCJ scenarios to HP scenarios. We introduce two theorems underlying the theoretical mixing properties of this parallel MCMC method. The method was tested on yeast and mammalian genomic data, and allowed us to provide estimates of the different modes of evolution in diverse lineages. © The Author 2010. Published by Oxford University Press. All rights reserved.

The metal/ionic liquid electrode impedance is practically resistive at the high frequency range of the usual electrochemical impedance spectroscopy measurements; the deviations are artefacts most probably due to the measurement system. Therefore the use of the interfacial capacitance representation of impedance spectra is further on suggested. © 2011 Elsevier Ltd. All rights reserved.

Wang Z.,Nankai University | Wang Z.,Hong Kong Baptist University | Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

While worldwide census data provide statistical evidence that firmly link the population density with several indicators of social welfare, the precise mechanisms underlying these observations are largely unknown. Here we study the impact of population density on the evolution of public cooperation in structured populations and find that the optimal density is uniquely related to the percolation threshold of the host graph irrespective of its topological details. We explain our observations by showing that spatial reciprocity peaks in the vicinity of the percolation threshold, when the emergence of a giant cooperative cluster is hindered neither by vacancy nor by invading defectors, thus discovering an intuitive yet universal law that links the population density with social prosperity. © 2012 American Physical Society.

Foldesy P.,Hungarian Academy of Sciences
ISCAS 2012 - 2012 IEEE International Symposium on Circuits and Systems | Year: 2012

This document reports various aspects of silicon field-effect transistor structures response under high frequency continuous wave and pulsed irradiation. The detectors have been manufactured in standard 0.18 um CMOS technology. Their response show formerly predicted behavior and novel effects. Implementing a pair of non-antenna coupled gate is found to increase the sensitivity. Several structures reveal additional effects like polarity change depending on gate source potential and drain current. A responsivity enhancement technique is presented as well in not noise free realistic setups. © 2012 IEEE.

Mayer I.,Hungarian Academy of Sciences
Chemical Physics Letters | Year: 2010

Using the concept of the effective minimal basis set introduced some time ago, a proper definition is proposed for the atomic promotion energy in the molecule, which the atom can be assigned after the orbital deformations are introduced but before any bonding, delocalization and charge transfer effects are taken into account. The first pivoting calculations indicate that these promotion energies can be quite substantial and are characteristic for the chemical nature of the atom. © 2010 Elsevier B.V. All rights reserved.

van der Pol E.,Laboratory of Experimental Clinical Chemistry | van der Pol E.,University of Amsterdam | Coumans F.,Laboratory of Experimental Clinical Chemistry | Coumans F.,University of Amsterdam | And 3 more authors.
Journal of Thrombosis and Haemostasis | Year: 2013

Cell-derived or extracellular vesicles, including microparticles and exosomes, are abundantly present in body fluids such as blood. Although such vesicles have gained strong clinical and scientific interest, their detection is difficult because many vesicles are extremely small with a diameter of less than 100 nm, and, moreover, these vesicles have a low refractive index and are heterogeneous in both size and composition. In this review, we focus on the relatively high throughput detection of vesicles in suspension by flow cytometry, resistive pulse sensing, and nanoparticle tracking analysis, and we will discuss their applicability and limitations. Finally, we discuss four methods that are not commercially available: Raman microspectroscopy, micro nuclear magnetic resonance, small-angle X-ray scattering (SAXS), and anomalous SAXS. These methods are currently being explored to study vesicles and are likely to offer novel information for future developments. © 2013 International Society on Thrombosis and Haemostasis.

Sali A.,Hungarian Academy of Sciences
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

In the present paper results on minimal Armstrong instances of certain integrity constraints in relational databases are surveyed that lead to coding theory type problems. First, branching dependencies are studied. Finding minimal Armstrong instances for some collections of these integrity constraints lead to a new metric space. Error correcting codes in that space have been investigated on their own right since then. In the second part Armstrong instances of functional dependencies are investigated when the size of the domain of each attribute is bounded by a constant q. These come up naturally in real life databases, as well as in the study of higher order data model. These instances can be directly considered as q-ary codes, if tuples are taken as codewords. © 2011 Springer-Verlag.

Szalay V.,Hungarian Academy of Sciences
Journal of Physical Chemistry A | Year: 2013

It is explained why the generalized discrete variable representation is variational neither with respect to the size (truncation) of the basis set nor with respect to the selection of grid points. © 2013 American Chemical Society.

Kasza T.,MOL Hungarian Oil and Gas Plc | Kallo D.,Hungarian Academy of Sciences | Hancsok J.,University of Pannonia
Fuel | Year: 2014

Quality improvement of bio-paraffin by isomerization was studied in presence of fatty acid over Pt/SAPO-11 catalyst in order to produce second generation biogasoil.