bluuebunny/crossref_metadata_2025 huggingface dataset:
Potassium diffusive coupling in neural networks
Authors: Durand Dominique M. , Park Eun-Hyoung , Jensen Alicia L.
Published: July 2010

Conventional neural networks are characterized by many neurons coupled together through synapses. The activity, synchronization, plasticity and excitability of the network are then controlled by its synaptic connectivity. Neurons are surrounded by an extracellular space whereby fluctuations in specific ionic concentration can modulate neuronal excitability. Extracellular concentrations of potassium ([K+]o) can generate neuronal hyperexcitability. Yet, after many years of research, it is still unknown whether an elevation of potassium is the cause or the result of the generation, propagation and synchronization of epileptiform activity. An elevation of potassium in neural tissue can be characterized by dispersion (global elevation of potassium) and lateral diffusion (local spatial gradients). Both experimental and computational studies have shown that lateral diffusion is involved in the generation and the propagation of neural activity in diffusively coupled networks. Therefore, diffusion-based coupling by potassium can play an important role in neural networks and it is reviewed in four sections. Section 2 shows that potassium diffusion is responsible for the synchronization of activity across a mechanical cut in the tissue. A computer model of diffusive coupling shows that potassium diffusion can mediate communication between cells and generate abnormal and/or periodic activity in small (§3) and in large networks of cells (§4). Finally, in §5, a study of the role of extracellular potassium in the propagation of axonal signals shows that elevated potassium concentration can block the propagation of neural activity in axonal pathways. Taken together, these results indicate that potassium accumulation and diffusion can interfere with normal activity and generate abnormal activity in neural networks.
Evidence on Irish financial analysts' and fund managers' views about dividends
Authors: McCluskey Thomas , Broderick Aoife , Boyle Amanda , Burton Bruce , Power David
Published: July 2010

Purpose

This paper aims to identify the views of Dublin‐based financial analysts and major Irish fund managers on dividends.

Design/methodology/approach

The paper uses semi‐structured interviews with 16 participants and analyses their responses concerning the role of dividends in the share screening process; the perceived relationship between dividend payment policy and share values; the impact of taxation and attitudes to share buybacks.

Findings

The results support the notion that dividends are an important in investor decision‐making processes and that dividends influence share valuations. Another key finding is that fund managers appear to be able to influence the dividend policy of Irish companies in which they have a shareholding. Finally, taxation issues appear relatively unimportant and the majority of fund managers prefer cash dividends to buybacks.

Originality/value

The paper addresses the issue of dividend policy from a qualitative standpoint, rather than the conventional large‐sample aggregate form of analysis. Moreover, whilst most other studies have investigated the issue from the corporate point of view, this investigation focuses on analysts' and fund managers' views.
Soybean FGAM synthase promoters direct ectopic nematode feeding site activity
Authors: Vaghchhipawala Zarir E , Schlueter Jessica A , Shoemaker Randy C , Mackenzie Sally A
Published: July 2010

Soybean cyst nematode (SCN) resistance in soybean is a complex oligogenic trait. One of the most important nematode resistance genes, rhg1, has been mapped to a distal region of molecular linkage group G in soybean. A simplified genetic system to identify soybean genes with modified expression in response to SCN led to the identification of several genes within the nematode feeding sites. The genes were mapped to reveal their linkage relationship to known QTLs associated with soybean cyst nematode (SCN) resistance. One candidate, a phosphoribosyl formyl glycinamidine (FGAM) synthase (EC 6.3.5.3) gene, mapped to the same genomic interval as the major SCN resistance gene rhg1 within linkage group G. Isolation of FGAM synthase from a soybean bacterial artificial chromosome (BAC) library revealed two highly homologous paralogs. The genes appeared to be well conserved between bacteria and humans. Promoter analysis of the two soybean homologs was carried out with the Arabidopsis thaliana – Heterodera schachtii system to investigate gene response to nematode feeding. The two promoters and their derived deletion constructions effected green fluorescent protein (GFP) expression within nematode feeding sites. The 1.0-kb promoter sequence immediately adjacent to the translation start site was sufficient to direct expression of GFP within syncytia. A wound-inducible element and a floral organ expression sequence were also identified within these promoters. Although a nematode-responsive element could not be identified, the observed expression of GFP within feeding sites supports the hypothesis that plant gene expression is redirected within feeding sites to benefit the parasite.Key words: FGAM synthase, promoter analysis, syncytium, Heterodera schachtii, soybean cyst nematode.
LatentSalleles are widespread in cultivated self-compatibleBrassica napus
Authors: Ekuere U U , Parkin I A.P , Bowman C , Marshall D , Lydiate D J
Published: July 2010

The genetic control of self-incompatibility in Brassica napus was investigated using crosses between resynthesized lines of B. napus and cultivars of oilseed rape. These crosses introduced eight C-genome S alleles from Brassica oleracea (S16, S22, S23, S25, S29, S35, S60, and S63) and one A-genome S allele from Brassica rapa (SRM29) into winter oilseed rape. The inheritance of S alleles was monitored using genetic markers and S phenotypes were determined in the F1, F2, first backcross (B1), and testcross (T1) generations. Two different F1hybrids were used to develop populations of doubled haploid lines that were subjected to genetic mapping and scored for S phenotype. These investigations identified a latent S allele in at least two oilseed rape cultivars and indicated that the S phenotype of these latent alleles was masked by a suppressor system common to oilseed rape. These latent S alleles may be widespread in oilseed rape varieties and are possibly associated with the highly conserved C-genome S locus of these crop types. Segregation for S phenotype in subpopulations uniform for S genotype suggests the existence of suppressor loci that influenced the expression of the S phenotype. These suppressor loci were not linked to the S loci and possessed suppressing alleles in oilseed rape and non-suppressing alleles in the diploid parents of resynthesized B. napus lines.Key words: self-incompatibility, B. oleracea, B. rapa, S locus, suppression.
Chromosome and nuclear DNA study on Luzula - a genus with holokinetic chromosomes
Authors: Kuta Elzbieta , Bohanec Borut , Dubas Ewa , Vizintin Liliana , Przywara Leslaw
Published: July 2010

Chromosomes and nuclear DNA amount were analyzed in leaf tissues of Luzula nivea, Luzula luzuloides, and Luzula multiflora. Intra- and interspecific karyological variability was stated. Chromosome numbers in diploids ranged 2n = 8-24 in L. nivea and L. luzuloides and 2n = 12-84 in hexaploid L. multiflora. Karyological variability resulted mainly from chromosome fission (agmatoploidy) and aneusomaty; chromosome fusion (symploidy) and polyploidy were also involved. Flow cytometric determination of nuclear genome size using propidium iodide staining gave values of 1.584 pg in L. luzuloides, 1.566 pg in L. nivea, and 3.034 pg in L. multiflora. Variability in relative nuclear genome size within species was measured by 4',6-diamidino-2-phenylindole staining. In contrast with previous reports, variability was fairly small and ranged from 1.796 to 1.864 pg in L. luzuloides, from 1.783 to 1.847 pg and from 1.737 to 1.808 pg in two populations (S and F) of L. nivea, respectively, and from 3.125 to 3.271 pg in L. multiflora. An intraplant (interleaf) genome size variation was also observed and its possible causes are discussed.Key words: Luzula, holokinetic chromosomes, agmatoploidy, symploidy, polyploidy, nuclear DNA amount, intraplant genome size variability, flow cytometry.
A genetic linkage map for Arctic char (Salvelinus alpinus): evidence for higher recombination rates and segregation distortion in hybrid versus pure strain mapping parents
Authors: Woram R A , McGowan C , Stout J A , Gharbi K , Ferguson M M , Hoyheim B , Davidson E A , Davidson W S , Rexroad C , Danzmann R G
Published: July 2010

We constructed a genetic linkage map for Arctic char (Salvelinus alpinus) using two backcrosses between genetically divergent strains. Forty-six linkage groups (expected = 39–41) and 19 homeologous affinities (expected = 25) were identified using 184 microsatellites, 129 amplified fragment length polymorphisms (AFLPs), 13 type I gene markers, and one phenotypic marker, SEX. Twenty-six markers remain unlinked. Female map distance (9.92 Morgans) was substantially higher than male map distance (3.90 Morgans) based on the most complete parental information (i.e., the F1hybrids). Female recombination rates were often significantly higher than those of males across all pairwise comparisons within homologous chromosomal segments (average female to male ratios within families was 1.69:1). The female hybrid parent had significantly higher recombination rates than the pure strain female parent. Segregation distortion was detected in four linkage groups (4, 8, 13, 20) for both families. In family 3, only the largest fish were sampled for genotyping, suggesting that segregation distortion may represent regions possessing influences on growth. In family 2, almost all cases showing segregation distortion involved markers in the female hybrid parent.Key words: salmonid fishes, polyploidy, homeology, genetic markers.
Inherited and somatic cytogenetic variability in Palearctic populations ofChironomus ripariusMeigen 1804 (Diptera, Chironomidae)
Authors: Sella Gabriella , Bovero Stefano , Ginepro Marco , Michailova Paraskeva , Petrova Ninel , Robotti Carlo Alberto , Zelano Vincenzo
Published: July 2010

Inter- and intracytogenetic variability was analyzed in 13 natural Palearctic populations of Chironomus riparius Meigen 1804 (syn. Chironomus thummi) by examining hereditary and somatic aberrations (mainly inversions) of the salivary gland polytene chromosomes. In total, 77 different types of inherited inversion sequences and 184 different types of somatic inversions were found. The median percent frequency of inherited inversions was 1.4% and karyotypic divergence between populations was very low. Most hereditary inversions were endemic and always in a heterozygous state. Only six inversion sequences, each of them shared by two very distant populations, may be considered a relic of very ancient ancestral inversions. Unlike inherited inversions, occurrence of somatic aberrations seems to increase with the overall rise in the level of heavy metal pollution of the sediments from which larvae were sampled. In contrast with what occurs in populations of other chironomid species, populations of C. riparius do not seem to undergo a process of cytogenetic differentiation.Key words: Chironomus thummi, polytene chromosomes, inversion polymorphism, somatic aberrations, heavy metal pollution.
Soybean bacterial artificial chromosome contigs anchored with RFLPs: insights into genome duplication and gene clustering
Authors: Mudge Joann , Huihuang Yan , Denny Roxanne L , Howe Dana K , Danesh Dariush , Marek Laura F , Retzel Ernie , Shoemaker Randy C , Young Nevin D
Published: July 2010

Surveying the soybean genome with 683 bacterial artificial chromosome (BAC) contiguous groups (contigs) anchored by restriction fragment length polymorphisms (RFLPs) enabled us to explore microsyntenic relationships among duplicated regions and also to examine the physical organization of hypomethylated (and presumably gene-rich) genomic regions. Numerous cases where nonhomologous RFLPs hybridized to common BAC clones indicated that RFLPs were physically clustered in soybean, apparently in less than 25% of the genome. By extension, we speculate that most of the genes are clustered in less than 275 M of the soybean genome. Approximately 40%–45% of this gene-rich portion is associated with the RFLP-anchored contigs described in this study. Similarities in genome organization among BAC contigs from duplicate genomic regions were also examined. Homoeologous BAC contigs often exhibited extensive microsynteny. Furthermore, paralogs recovered from duplicate contigs shared 86%–100% sequence identity.Key words: Glycine max, bacterial artifical chromosome, restriction fragment length polymorphism, genome duplication, gene distribution.
ON THE DISCOVERY OF COHERENT BREMSSTRAHLUNG IN A SINGLE CRYSTAL AT THE FRASCATI NATIONAL LABORATORIES
Authors: BARBIELLINI G. , MURTAS G.P. , DABAGOV S.B.
Published: July 2010

Since the end of 1950s the Frascati National Laboratories have started intense research program devoted to studying the coherent phenomena of relativistic electron interactions in crystals. First results were impressive: Frascati's Spectrometer has first detected coherent radiation by electrons in crystals, i.e. coherent bremsstrahlung. The discovery not only proved the Ferretti-Uberall prediction, but also has corrected the theory of coherent bremstrahlung. Carrying out intensive studies on coherent radiation phenomena in crystals a number of innovative techniques to measure fine features of radiation, such as polarization measurents, was developed. The Frascati's group was even close for the first time to observe channeling radiation discovered about two decades later the pioneering work on coherent bremsstrahlung.
DIFFRACTED CHANNELING RADIATION AND OTHER COMPOUND RADIATION PROCESSES
Authors: NITTA HIDEO
Published: July 2010

Radiations from a crystal irradiated with relativistic charged particles are reviewed with the emphasis on their fundamental processes. As their "compound processes" diffraction of both channeling radiation and coherent bremsstrahlung are considered. Coherent polarization radiation from neutral particles with magnetic moment is discussed within the framework of classical electrodynamics.
CHANNELING EXPERIMENTS WITH ELECTRONS AT THE MAINZ MICROTRON MAMI
Authors: LAUTH W. , BACKE H. , KUNZ P. , RUEDA A.
Published: July 2010

The dechanneling process of electrons in silicon single crystals has been studied at the Mainz Microtron MAMI for (110)-planar channeling of electrons at beam energies between 195 and 855 MeV. Dechanneling lengths were derived from a high and a low energy loss signal of the electrons which were recorded as function of the crystal orientation with respect to the beam direction for various crystal thicknesses in the range between 14.7 µm and 467 µm. The high energy loss signal corresponds to an energy loss of about 75 % of the total electron energy by emission of a bremsstrahlung photon, while the low energy signal to an energy loss of 0.7-1.7 % by emission of channelling radiation. While the high energy signal saturates as function of the crystal thickness, the low energy signal does not. The nearly constant dechanneling length of about 35 µm, as extracted from the high energy signal, is interpreted to originate from a small fraction of electron which initially occupy deeply bound quantum states.
DECHANNELING OF POSITRONS BY DISLOCATIONS: EFFECTS OF ANHARMONIC INTERACTIONS
Authors: GEORGE JUBY , PATHAK A. P.
Published: July 2010

A quantum mechanical treatment of the effects of dislocations on planar channeling of positrons is presented. The effects of anharmonic terms on the positron planar potential are considered in these calculations. The wavefunction of channeled positron in the perfect channel and the two regions of dislocation affected channel are found and compared with harmonic case. The corresponding effects on bound states and the transitions among these states are calculated. The transition probabilities and the resulting dechanneling probabilities are found for initially channelled particles in states |0〉 and |1〉. The calculations are carried out with varying channel distance from the dislocation core. Applications of anharmonic interactions on channeling radiation are also investigated.
NEW FEATURES OF DIFFRACTED CHANNELING RADIATION FROM ELECTRONS IN Si AND LiF CRYSTALS
Authors: KOROTCHENKO K.B. , PIVOVAROV YU.L. , TUKHFATULLIN T.A.
Published: July 2010

It is shown that the band structure of transverse energy levels for (111) planar channeled electrons in the Si and LiF crystals qualitatively changes the angular distributions of X-rays emitted at the Bragg angles compared to calculations, which do not take into account this effect [5-7].
NEW EXPERIMENTAL RESULTS WITH OPTICAL DIFFRACTION RADIATION DIAGNOSTICS
Authors: CHIADRONI E. , CASTELLANO M. , CIANCHI A. , HONKAVAARA K. , KUBE G.
Published: July 2010

The characterization of the transverse phase space for high charge density and high energy electron beams is demanding for the successful development of the next generation light sources and linear colliders.

Due to its non-invasive and non-intercepting features, Optical Diffraction Radiation (ODR) is considered as one of the most promising candidates to measure the transverse beam size and angular divergence.

The recent results of our experiment, based on the detection of the ODR angular distribution to measure the electron beam transverse parameters and set up at FLASH (DESY), are presented. A thin stainless steel mask has been installed at 45° with respect to the DR target and normally to the beam propagation to reduce the contribution of synchrotron radiation (SR) background. In addition, interference between the ODR emitted on the shielding mask in the forward direction and the radiation from the DR target in the backward direction is observed. This is what we call Optical Diffraction Interferometry (ODRI). The contribution of this interference effect to the ODR angular distribution pattern and, consequently, its impact on the beam transverse parameters is discussed.
EXPERIMENTAL INVESTIGATION OF SMITH–PURCELL RADIATION FOCUSING BY USING THE PARABOLIC GRATINGS
Authors: NAUMENKO G.A. , POTYLITSYN A. P. , SUKHIKH L. G. , POPOV YU.A.
Published: July 2010

The Smith–Purcell radiation generated by relativistic electrons has been studied experimentally. To investigate the posibility of radiation focusing in the pre-wave zone two types of concave gratings focusing radiation in azimuthal and polar planes have been used. Comparison of radiation characteristics of such gratings with the flat grating ones in the same conditions has showed that application of concave gratings may significantly increase coherent Smith–Purcell radiation spatial density.
STUDY OF THE ELECTRONIC AND STRUCTURAL PROPERTIES OF ZnO CLUSTERS
Authors: SANYAL BIPLAB , MOOKERJEE ABHIJIT
Published: July 2010

We present a systematic first-principle study of the structures, energetics and electronic structure of (ZnO) n clusters in the size range 1 ≤ n≤ 12. We show that the planar ring structures are stable for n < 8, while spheroidal structures made out of rings of (ZnO) 3 and (ZnO) 2 are stable for n ≥ 8. We examine the binding energies and HOMO–LUMO gaps of the clusters and try to understand our results from simple physical ideas.
STABLE SPHEROIDAL CAP SHAPES OF DEPOSITED ATOMIC CLUSTERS
Authors: POENARU D. N. , GHERGHESCU R. A. , GREINER W.
Published: July 2010

Neutral short and long spheroidal cap clusters have been investigated within the liquid drop model. Analytical results have been obtained for the deformation-dependent surface and curvature energies. A large variety of experimentally determined shapes (both oblate and prolate) are explained by simulating the interaction energy with the substrate with a modified surface tension of the base, and by changing the missing or extended height of the cap, d. The results are illustrated for Na 56 and Na 148 atomic clusters.
WHY HOLES ARE NOT LIKE ELECTRONS IV: HOLE UNDRESSING AND SPIN CURRENT IN THE SUPERCONDUCTING STATE
Authors: HIRSCH J. E.
Published: July 2010

In paper III of this series we proposed a scenario of superconductivity driven by hole "undressing" that involved a complete redistribution of the occupation of single particle energy levels: the holes near the top of the band were proposed to all condense to the bottom of the band. Here we consider a less drastic redistribution involving electrons with a definite spin chirality and show that it is in fact energetically favored by the Coulomb exchange matrix element J over the scenario proposed earlier. It is shown that spin splitting with chiral states reduces the Coulomb repulsion and hence that the Coulomb repulsion promotes spin splitting. Superconductors are proposed to possess a spin-split hole "core" at the bottom of the electronic conduction band in addition to a spin-split Fermi surface. The Dirac sea is proposed to play a key role. The new scenario leads naturally to the existence of a spin current in the superconducting state and is consistent with the Spin Meissner effect and negative charge expulsion discussed earlier within the theory of hole superconductivity.
BEHAVIOR OF SOUND WAVES IN SHEPHERD FLUTE ON THE BASIS OF QUANTUM THEORY OF INDIVIDUAL PHONONS
Authors: KRSTIĆ SONJA , SAJFERT VJEKOSLAV , TOŠIĆ BRATISLAV
Published: July 2010

Using the linearized Hamiltonian of individual phonon, it was shown that Schrödinger's equation of individual phonon is by form identical with classical hyperbolic equation. It was also shown that damper in shepherd's flute is reflexive for high frequencies and transparent for low ones. This result was experimentally tested by authors and good agreement of theory and experiment was found. The propagation of sound in parallelopipedal and cylindrical shepherd's flute was investigated. It turned out that parallelopipedal sound propagates in z-direction, only, while in cylindrical one besides plane waves in z-direction the damped waves in x, y plane appear.
BRAIN DYNAMICS AT MULTIPLE SCALES: CAN ONE RECONCILE THE APPARENT LOW-DIMENSIONAL CHAOS OF MACROSCOPIC VARIABLES WITH THE SEEMINGLY STOCHASTIC BEHAVIOR OF SINGLE NEURONS?
Authors: EL BOUSTANI SAMI , DESTEXHE ALAIN
Published: July 2010

Nonlinear time series analyses have suggested that the human electroencephalogram (EEG) may share statistical and dynamical properties with chaotic systems. During slow-wave sleep or pathological states like epilepsy, correlation dimension measurements display low values, while in awake and attentive subjects, there is no such low dimensionality, and the EEG is more similar to a stochastic variable. We briefly review these results and contrast them with recordings in cat cerebral cortex, as well as with theoretical models. In awake or sleeping cats, recordings with microelectrodes inserted in cortex show that global variables such as local field potentials (local EEG) are similar to the human EEG. However, neuronal discharges are highly irregular and exponentially distributed, similar to Poisson stochastic processes. To reconcile these results, we investigate models of randomly-connected networks of integrate-and-fire neurons, and also contrast global (averaged) variables, with neuronal activity. The network displays different states, such as "synchronous regular" (SR) or "asynchronous irregular" (AI) states. In SR states, the global variables display coherent behavior with low dimensionality, while in AI states, the global activity is high-dimensionally chaotic with exponentially distributed neuronal discharges, similar to awake cats. Scale-dependent Lyapunov exponents and ∊-entropies show that the seemingly stochastic nature at small scales (neurons) can coexist with more coherent behavior at larger scales (averages). Thus, we suggest that brain activity obeys a similar scheme, with seemingly stochastic dynamics at small scales (neurons), while large scales (EEG) display more coherent behavior or high-dimensional chaos.
STATISTICAL COMPLEXITY AND NONTRIVIAL COLLECTIVE BEHAVIOR IN ELECTROENCEPHALOGRAPHIC SIGNALS
Authors: ESCALONA-MORÁN M. , COSENZA M. G. , LÓPEZ-RUIZ R. , GARCÍA P.
Published: July 2010

We calculate a measure of statistical complexity from the global dynamics of electroencephalographic (EEG) signals from healthy subjects and epileptic patients, and are able to establish a criterion to characterize the collective behavior in both groups of individuals. It is found that the collective dynamics of EEG signals possess relatively higher values of complexity for healthy subjects in comparison to that for epileptic patients. To interpret these results, we propose a model of a network of coupled chaotic maps where we calculate the complexity as a function of a parameter and relate this measure with the emergence of nontrivial collective behavior in the system. Our results show that the presence of nontrivial collective behavior is associated to high values of complexity; thus suggesting that similar dynamical collective process may take place in the human brain. Our findings also suggest that epilepsy is a degenerative illness related to the loss of complexity in the brain.
FROM DYSON–SCHWINGER EQUATIONS TO THE RIEMANN–HILBERT CORRESPONDENCE
Authors: SHOJAEI-FARD ALI
Published: July 2010

In this paper, with the study of combinatorial Dyson–Schwinger equations at the level of the universal Hopf algebra of renormalization and with the extension of the universality of this specific Hopf algebra and also category of flat equisingular vector bundles to the level of these equations, we are going to consider the notion of a geometric description from nonperturbative theory.
GENERALIZED β-CONFORMAL CHANGE OF FINSLER METRICS
Authors: YOUSSEF NABIL L. , ABED S. H. , ELGENDI S. G.
Published: July 2010

In this paper, we introduce and investigate a general transformation or change of Finsler metrics, which is referred to as a generalized β-conformal change: [Formula: see text] This transformation combines both β-change and conformal change in a general setting. The change, under this transformation, of the fundamental Finsler connections, together with their associated geometric objects, are obtained. Some invariants and various special Finsler spaces are investigated under this change. The most important changes of Finsler metrics existing in the literature are deduced from the generalized β-conformal change as special cases.
HERMITIAN VECTOR FIELDS AND COVARIANT QUANTUM MECHANICS OF A SPIN PARTICLE
Authors: CANARUTTO DANIEL
Published: July 2010

In the context of Covariant Quantum Mechanics for a spin particle, we classify the "quantum vector fields", i.e. the projectable Hermitian vector fields of a complex bundle of complex dimension 2 over spacetime. Indeed, we prove that the Lie algebra of quantum vector fields is naturally isomorphic to a certain Lie algebra of functions of the classical phase space, called "special phase functions". This result provides a covariant procedure to achieve the quantum operators generated by the quantum vector fields and the corresponding observables described by the special phase functions.
BI-HAMILTONIAN STRUCTURE OF THE KAWACHI EQUATIONS
Authors: TUDORAN RĂZVAN M. , GÎRBAN ANANIA
Published: July 2010

The age-independent deterministic model for the transmission of a constant rumor, recently proposed by Kawachi, is shown to admit a bi-Hamiltonian structure, structure that is leading to its complete integrability.
k-SYMPLECTIC AND k-COSYMPLECTIC LAGRANGIAN FIELD THEORIES: SOME INTERESTING EXAMPLES AND APPLICATIONS
Authors: MUÑOZ-LECANDA MIGUEL C. , SALGADO MODESTO , VILARIÑO SILVIA
Published: July 2010

In this paper, we present a geometric version of several examples of partial differential equations which appear in field theories. These examples are described using the k-symplectic and k-cosymplectic Lagrangian formalism.
ON AXOPLASMIC PRESSURE WAVES AND THEIR POSSIBLE ROLE IN NERVE IMPULSE PROPAGATION
Authors: RVACHEV MARAT M.
Published: July 2010

It is suggested that the propagation of the action potential is accompanied by an axoplasmic pressure pulse propagating in the axoplasm along the axon length. The pressure pulse stretch-modulates voltage-gated Na+(Nav) channels embedded in the axon membrane, causing their accelerated activation and inactivation and increasing peak channel conductance. As a result, the action potential propagates due to mechano-electrical activation of Nav channels by straggling ionic currents and the axoplasmic pressure pulse. The velocity of such propagation is higher than in the classical purely electrical Nav activation mechanism, and it may be close to the velocity of propagation of pressure pulses in the axoplasm. Extracellular Ca2+ions influxing during the voltage spike, or Ca2+ions released from intracellular stores, may trigger a mechanism that generates and augments the pressure pulse, thus opposing its viscous decay. The model can potentially explain a number of phenomena that are not contained within the purely electrical Hodgkin–Huxley-type framework: the Meyer–Overton rule for the effectiveness of anesthetics, as well as various mechanical, optical and thermodynamic phenomena accompanying the action potential. It is shown that the velocity of propagation of axoplasmic pressure pulses is close to the measured velocity of the nerve impulse, both in absolute magnitude and in dependence on axon diameter, degree of myelination and temperature.
EFFECT OF NON-CODING RNA ON BISTABILITY AND OSCILLATIONS IN THE mRNA-PROTEIN INTERPLAY
Authors: ZHDANOV VLADIMIR P.
Published: July 2010

The feedbacks between the mRNA and protein synthesis may result in kinetic bistability and oscillations. Two generic models predicting bistability include, respectively, a gene with positive regulation of the mRNA production by protein and two genes with mutual suppression of the mRNA production due to negative regulation of the gene transcription by protein. The simplest model predicting oscillations describes a gene with negative regulation of the mRNA production by protein formed via mRNA translation and a few steps of conversion. We complement these models by the steps of non-coding RNA (ncRNA) formation and ncRNA-mRNA association and degradation. With this extension, the bistability can often be observed as well. Without and with ncRNA, the biochemistry behind the steady states may be different. In the latter case, for example, ncRNA may control the mRNA population in the situations when this population is relatively small, and one can observe a switch in the mRNA, protein and ncRNA populations. Our analysis of oscillatory kinetics of the mRNA-protein interplay shows that with ncRNA the oscillations may be observed in a wider range of parameters and the amplitude of oscillations may be larger.
ON EDGE-CONNECTIVITY AND SUPER EDGE-CONNECTIVITY OF INTERCONNECTION NETWORKS MODELED BY PRODUCT GRAPHS
Authors: WANG CHUNXIANG
Published: July 2010

The super edge-connectivity λ′ of a connected graph G is the minimum cardinality of an edge-cut F in G such that every component of G–F contains at least two vertices. Let two connected graphs Gm and Gp have m and p vertices, minimum degree δ(Gm) and δ(Gp), edge-connectivity λ(Gm) and λ(Gp), respectively. This paper shows that min {pλ(Gm), λ(Gp) + δ(Gm), δ(Gm)(λ(Gp) + 1), (δ(Gm) + 1)λ(Gp)} ≤ λ(Gm * Gp) ≤ δ(Gm) + δ(Gp), where the product graph Gm * Gp of two given graphs Gm and Gp, defined by J. C. Bermond et al. [J. Combin. Theory B36 (1984) 32–48] in the context of the so-called (△, D)-problem, is one interesting model in the design of large reliable networks. Moreover, this paper determines λ′(Gm * Gp) ≤ min {pδ(Gm), ξ(Gp) + 2δ(Gm)} and λ′(G1 ⊕ G2) ≥ min {n, λ1 + λ2} if δ1 = δ2.
PACKING SHELVES WITH ITEMS THAT DIVIDE THE SHELVES' LENGTH: A CASE OF A UNIVERSAL NUMBER PARTITION PROBLEM
Authors: DROR MOSHE , ORLIN JAMES B. , ZHU MICHAEL
Published: July 2010

This note examines the likelihood of packing two identical one dimensional shelves of integer length L by items whose individual lengths are divisors of L, given that their combined length sums-up to 2L. We compute the number of packing failures and packing successes for integer shelve lengths L, 1 ≤ L ≤ 1000, by implementing a dynamic programming scheme using a problem specific "boundedness property". The computational results indicate that the likelihood of a packing failure is very rare. We observe that the existence of packing failures is tied to the number of divisors of L and prove that the number of divisors has to be at least 8 for a packing failure to exist.
SOLVING A MULTI-OBJECTIVE FLEXIBLE JOB SHOP SCHEDULING PROBLEM WITH TIMED PETRI NETS AND GENETIC ALGORITHM
Authors: HUANG HEJIAO , LU TAIPING
Published: July 2010

The method presented in this paper is used to solve flexible job shop scheduling problem (JSP) with multiple objectives, which is much more complex than the classical JSP. Based on timed Petri net model, genetic algorithm is applied to solve the scheduling problems. The chromosomes are composed by sequences of transitions, the crossover and mutation operations are based on transition sequences. The experiment result shows that a definite solution to a specific flexible job shop scheduling problem can be found.
ON PRODUCT OF FUZZY SUBHYPERLATTICE AND INTERVAL-VALUED FUZZY SUBHYPERLATTICE
Authors: FENG YUMING , ZOU LIMIN
Published: July 2010

We first introduced the notions of (anti-)fuzzy subhyperlattices. Then we proved that the (anti-)product of two (anti-)fuzzy subhyperlattices is a (anti-)fuzzy subhyperlattice. Lastly, we generalized some of our results to interval-valued fuzzy version.
ON THE LOWER BOUND OF THE COMPETITIVE RATIO FOR THE WEIGHTED ONLINE ROOMMATES PROBLEM
Authors: BANERJEE SATYAJIT
Published: July 2010

We show that the best possible worst case competitive ratio of any deterministic algorithm for weighted online roommates problem is arbitrarily close to 4. This proves that the 4-competitive algorithm proposed by Bernstein and Rajagopalan [3] for the weighted version of the online roommates problem actually attains the best possible competitive ratio.
FRÉCHET DISTANCE PROBLEMS IN WEIGHTED REGIONS
Authors: CHEUNG YAM KI , DAESCU OVIDIU
Published: July 2010

We discuss two versions of the Fréchet distance problem in weighted planar subdivisions. In the first one, the distance between two points is the weighted length of the line segment joining the points. In the second one, the distance between two points is the length of the shortest path between the points. In both cases, we give algorithms for finding a (1 + ∊)-factor approximation of the Fréchet distance between two polygonal curves. We also consider the Fréchet distance between two polygonal curves among polyhedral obstacles in [Formula: see text] (1/∞ weighted region problem) and present a (1 + ∊)-factor approximation algorithm.
Carbon-Nanotube-Enhanced Thermal Contactor in Low Contact Pressure Region
Authors: Tsukamoto Takashiro , Esashi Masayoshi , Tanaka Shuji
Published: July 2010

We first demonstrated considerable reduction of thermal contact resistance (TCR) of a bending thermal contactor in microscale using carbon nanotubes (CNTs). TCR reduction using CNTs were previously reported with flat contact surface, but the thermal contact surfaces of actual microdevices often bend because of their residual and thermal stress. We evaluated both flat and bending contact surfaces to apply this method for a variety of applications. The TCR reduction is observed not only with a flat contact surface but also a bending surface. A bending micro thermal contactor with a plasma-enhanced chemical vapor deposition (PECVD)-grown 10 µm long “CNT carpet” shows a TCR ofca.600 mm2K/W at a contact pressure of 20 kPa, which is about 1/10 to the TCR of the reference contactor without “CNT carpet”. This technique is useful for micro thermal devices such as micro thermal switch.
Acute Cardiac Failure due to Intra-Atrial Mass Caused by Zygomycetes in an Immunocompromised Paediatric Patient
Authors: van de Glind G. J. , Gidding C. E. M. , Verlaat C. M. W. , Duthoi K. , Backx A. P. C. , Verweij P. E. , Warris A.
Published: July 2010

Cardiac zygomycosis can be a critical condition with sudden onset of severe congestive heart failure followed by severe hemodynamic deterioration. We report a fatal course of disseminated fungal infection with a massive intra-atrial thrombosis caused by a zygomycete, in a five year old boy treated for acute lymphoblastic leukaemia. In addition, we discuss the literature concerning infections caused by zygomycetes involving the heart. Prognosis is poor. A high index of suspicion and an aggressive diagnostic and therapeutic approach with the prompt start of preemptive antifungal therapy are key factors to improve outcome.
On the QoS of IPTV and Its Effects on Home Networks
Authors: Qiu Dongyu
Published: July 2010

In Internet Protocol Television (IPTV) systems, Quality-of-Service (QoS) is a critical factor for user satisfaction. In this paper, we first propose a queueing model for IPTV systems and discuss how to ensure the QoS of IPTV. We then use the model to analyze the effects of IPTV traffic on other applications in home networks. We find that TCP congestion control may not work well under this circumstance and propose a new approach to improve the performance of TCP. We also verify our results throughns2simulations.
Inhibition of Methylglyoxal-Mediated Protein Modification in Glyoxalase I Overexpressing Mouse Lenses
Authors: Gangadhariah Mahesha H. , Mailankot Maneesh , Reneker Lixing , Nagaraj Ram H.
Published: July 2010

Objective. Here we tested the role of Glo I in the prevention of advanced glycation end product (AGE) formation in transgenic mouse lenses.Methods. A transgenic animal line that expressed high levels of human Glo I in the lens was developed from the C57B6 mouse strain. The role of Glo I in the inhibition of MGO-AGE formation was tested in organ-cultured lenses.Results. Organ culture of Wt and Glo I lenses with 5 mM D, L-glyceraldehyde (GLD) enhanced MGO by 29-fold and 17-fold in Wt lenses and Glo I lenses, respectively. Argpyrimidine levels were192±73pmoles/mg protein, and hydroimidazolone levels were22±0.7units/μgprotein in GLD-incubated Wt lenses. In Glo I lenses, formation of AGEs was significantly inhibited; the argpyrimidine levels were82±18pmoles/mg protein, and the HI levels were2.6±2.3units/μgprotein. Incubation of Wt lens proteins with 5 mM ribose for 7 days resulted in the formation of pentosidine. However, the levels were substantially higher in Glo I lens proteins incubated with ribose.Conclusion. Our study provides direct evidence that Glo I activity plays an important role in the regulation of AGE synthesis in the lens; while Glo I activity blocks the formation of MGO-AGEs, it might promote the formation of sugar-derived AGEs.
High-Energy X-Ray Microprobe System with Submicron Resolution for X-Ray Fluorescence Analysis of Uranium in Biological Specimens
Authors: Terada Yasuko , Homma-Takeda Shino , Takeuchi Akihisa , Suzuki Yoshio
Published: July 2010

Total-external-reflection Kirkpatrick-Baez mirror optics for high-energy X-rays have been applied to the X-ray microprobe at beamline 37XU of SPring-8. A focused beam size of 1.0 μm (V)×0.83 μm (H) has been achieved at an X-ray energy of 30 keV, and a total photon flux of the focused beam was about 5×109 photons/s. Micro-X-ray fluorescence (μ-XRF) analysis of the uranium distribution in rat kidneys has been performed with the mirror-focused beam. The sensitivity of uranium was evaluated from the XRF intensity of thin standard samples, and the minimum detection limit was estimated at 10 μg/g. The high-spatial-resolution analysis revealed that uranium was concentrated in the epithelium of the proximal tubules in the inner cortex. The maximum concentration of uranium in the tubule was estimated to be 503 μg/g using a semiquantitative evaluation.
Finding Biomarker Signatures in Pooled Sample Designs: A Simulation Framework for Methodological Comparisons
Authors: Telaar Anna , Nürnberg Gerd , Repsilber Dirk
Published: July 2010

Detection of discriminating patterns in gene expression data can be accomplished by using various methods of statistical learning. It has been proposed that sample pooling in this context would have negative effects; however, pooling cannot always be avoided. We propose a simulation framework to explicitly investigate the parameters of patterns, experimental design, noise, and choice of method in order to find out which effects on classification performance are to be expected. We use a two-group classification task and simulated gene expression data with independent differentially expressed genes as well as bivariate linear patterns and the combination of both. Our results show a clear increase of prediction error with pool size. For pooled training sets powered partial least squares discriminant analysis outperforms discriminance analysis, random forests, and support vector machines with linear or radial kernel for two of three simulated scenarios. The proposed simulation approach can be implemented to systematically investigate a number of additional scenarios of practical interest.
Primary Malignant Fibrous Histiocytoma of the Lung: A Case Report
Authors: Tsangaridou I. , Papamihalis G. , Stathopoulos K. , Konstantinopoulos O. , Thanos L.
Published: July 2010

Primary malignant fibrous histiocytoma (MFH) of the lung is extremely rare although it is among the most common soft tissue sarcomas in adults. Surgery is the primary mode of therapy, with high rates of local and distant recurrence, while radiation therapy appears to be a very useful adjunct, decreasing local relapse. We report a case of primary malignant fibrous histiocytoma of the lung. Fourteen years after surgical resection, the patient is still alive although with multiple metastatic lesions throughout his body.
On the Efficiency of the Multi-Channel Analysis of Surface Wave Method for Shallow and Semi-Deep Loose Soil Layers
Authors: Khaheshi Banab Kasgin , Motazedian Dariush
Published: July 2010

The multi-channel analysis of surface waves (MASWs) method was used to obtain the shear wave velocity variations through near surface (depth < 30 m) and semi-deep (30 m < depth < 100 m) soil layers in the city of Ottawa, Canada. Sixteen sites were examined to evaluate the capability of the active and passive MASW methods for cases where the shear wave velocity(Vs)contrast between very loose soil (Vs< 200 m/s) and very firm bedrock (Vs> 2,300 m/s) is very large. The MASW velocity results compared with those of other geophysical approaches, such as seismic reflection/refraction methods and borehole data, where available, mostly confirming the capability of the MASW method to distinguish the high shear wave velocity contrast in the study area. We have found that, of the inversion procedures of MASW data, the random search inversion technique provides better results than the analytical generalized inversion method.
A Comprehensive Study of Progressive Cytogenetic Alterations in Clear Cell Renal Cell Carcinoma and a New Model for ccRCC Tumorigenesis and Progression
Authors: Zhang Zhongfa , Wondergem Bill , Dykema Karl
Published: July 2010

We present a comprehensive study of cytogenetic alterations that occur during the progression of clear cell renal cell carcinoma (ccRCC). We used high-density high-throughput Affymetrix 100 K SNP arrays to obtain the whole genome SNP copy number information from 71 pretreatment tissue samples with RCC tumors; of those, 42 samples were of human ccRCC subtype. We analyzed patterns of cytogenetic loss and gain from different RCC subtypes and in particular, different stages and grades of ccRCC tumors, using a novel algorithm that we have designed. Based on patterns of cytogenetic alterations in chromosomal regions with frequent losses and gains, we inferred the involvement of candidate genes from these regions in ccRCC tumorigenesis and development. We then proposed a new model of ccRCC tumorigenesis and progression. Our study serves as a comprehensive overview of cytogenetic alterations in a collection of 572 ccRCC tumors from diversified studies and should facilitate the search for specific genes associated with the disease.
Remarks on Recent Fixed Point Theorems
Authors: Singh SL , Mishra SN
Published: July 2010

Coincidence and fixed point theorems for a new class of contractive, nonexpansive and hybrid contractions are proved. Applications regarding the existence of common solutions of certain functional equations are also discussed.
Every Wheeze Does Not Merit a Puffer! Case of an Overnight Cure of Chronic Asthma
Authors: Balakrishnan Santosh , Doddi Sudeendra , Helme Sophie , Sinha Prakash
Published: July 2010

The peril of incorrect diagnostic labelling is highlighted by this case of acute respiratory distress caused by a retrosternal recurrent goitre. An initial clinical diagnosis which cannot be fully validated on investigation with unexpected or poor response to treatment should prompt consideration and investigation for an alternative explanation.
On Deployment of Multiple Base Stations for Energy-Efficient Communication in Wireless Sensor Networks
Authors: Lin Yunyue , Wu Qishi , Cai Xiaoshan , Du Xiaojiang , Kwon Ki-Hyeon
Published: July 2010

Data transmission from sensor nodes to a base station or a sink node often incurs significant energy consumption, which critically affects network lifetime. We generalize and solve the problem of deploying multiple base stations to maximize network lifetime in terms of two different metrics under one-hop and multihop communication models. In the one-hop communication model, the sensors far away from base stations always deplete their energy much faster than others. We propose an optimal solution and a heuristic approach based on the minimal enclosing circle algorithm to deploy a base station at the geometric center of each cluster. In the multihop communication model, both base station location and data routing mechanism need to be considered in maximizing network lifetime. We propose an iterative algorithm based on rigorous mathematical derivations and use linear programming to compute the optimal routing paths for data transmission. Simulation results show the distinguished performance of the proposed deployment algorithms in maximizing network lifetime.
When a Doctor Becomes a Patient with a Mystery Illness: A Case Report
Authors: Haver Brit
Published: July 2010

Symptoms presenting as mental disorders may represent epileptic discharges, especially from the temporal lobe. Both mental and somatic symptoms are common in temporal lobe epilepsy, which may confuse doctors, leading to extensive medical examinations and tests, false diagnoses, and ineffective treatment. Also, the episodic nature and variety of symptoms between as well as in individual cases hinder correct diagnosis. Since epileptic discharges may be visible on EEG only during an epileptic fit—and may need highly specialized equipment to detect—many cases are undiagnosed or treated under false diagnoses. The author believes that undetected temporal lobe epilepsy falsely labelled as psychiatric disorders are common. Specific and effective treatment exists for temporal lobe epilepsy, making correct diagnosis important. This history—based on the author's personal experience—also illustrates aspects of the physician-patients' problems and resources, as well as the gap between somatic and psychiatric medicine concerning this rather common neuropsychiatric disorder.