bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards meaningful stakeholder comprehension of sour gas facility risk assessments
Authors: McAuley Claire , Hrudey Steve E
Published: February 2006

The disconnect between a risk assessment by the proponent of a sour gas development and the stakeholders affected is addressed by attempting to understand the implied logic and reasoning embedded in the different perspectives. While a risk assessment may assure the Alberta Energy and Utilities Board (EUB) and the proponent that there is no immediate danger to the stakeholders, public response often indicates that the stakeholders have not been reassured and their specific concerns remain unaddressed. The concepts of "I am at risk" vs. "There may be a risk" are developed in conjunction with the concept of the assumed, but unknowable, exposed population. Effective risk communication requires a two-way process to address the value judgements that scientific methodology cannot resolve. Stakeholders were not polled for their response to risk assessments; one author (CM) attempted to bridge this gulf on the basis of relevant personal experience. The concepts discussed are applicable to a wide range of issues involving accidental releases of chemicals. Key words: risk, risk communication, risk management, sour gas facilities, hydrogen sulphide.
Effect of hydraulic retention time and attachment media on sulfide production by sulfate reducing bacteria
Authors: Polo Beatriz C , Bewtra Jatinder K , Biswas Nihar
Published: February 2006

The effects of hydraulic retention time (HRT) and attachment media on the rate of microbial sulfate reduction with lactate as a carbon and energy source were investigated for sulfate reducing bacteria (SRB). Laboratory experiments were conducted in semi-continuous and continuous modes by using synthetic feed in three parallel 10-L PlexiglasTM upflow anaerobic reactors. The lactate:sulfate was maintained below 2 for proper SRB activity. Results indicated that 70% of the lactate fed was bio-oxidized and 30% was biosynthesized, which showed that the energy production reaction dominated over the synthesis reaction in non-packed reactors. Continuous mode operation of three upflow anaerobic suspended growth reactors yielded effluent sulfide concentrations as high as 190 mg/L at the optimum conditions of 20 h of HRT, 1.5 m/d of upflow velocity, and an organic loading rate (OLR) of 6 kg d–1 m–3, regardless of the presence of attachment media in the reactor. The critical HRT was 10 h. Lower retention times showed a significant decrease in the effluent sulfide concentration and washout of biomass. When the OLR was doubled, the rate of sulfide production increased proportionately. Key words: sulfate reducing bacteria (SRB), hydraulic retention time (HRT), support media, sulfide production.
Biodosimetry testing of a simplified computational model for the UV disinfection of wastewater
Authors: Templeton M R , Hofmann R , Andrews R C , Whitby G E
Published: February 2006

A simplified computational model of the ultraviolet (UV) disinfection dose delivered to wastewater was developed and the model outputs were compared with pilot-scale biodosimetry data. The model assumed plug flow, an assumption that may apply for some open channel UV reactors designed for wastewater disinfection and in which case may eliminate the need for involved and expensive computational fluid dynamics analyses of flow patterns. The reactor residence times derived from this assumption were combined with the output from a two-dimensional, point-source summation UV irradiance model to calculate UV dose. The output from the irradiance model was adapted to account for the cross-sectional distribution of UV irradiance within the reactor. Two UV reactor configurations were modeled and pilot-tested at two UV transmittance (UVT) values that are typical for wastewater. The simplified model predicted doses that fell within the range of the observed UV doses under some flow and UVT conditions, however it did so inconsistently and over-predicted the doses at the highest tested flow rates. This was concluded to be due to a breakdown of the simplified plug flow assumption due to deviations in the velocity field distribution at higher flows. Therefore, while this modeling approach may provide "back of the envelope" initial estimates of the UV doses supplied to wastewater and may allow a qualitative evaluation of the effect of adjusting UV reactor design parameters (e.g., channel width, lamp spacing) on the resulting UV dose, the precise quantitative prediction of UV dose must continue to rely on more sophisticated models. Key words: ultraviolet disinfection, computational modeling, wastewater treatment.
Inactivation of Stachybotrys chartarum grown on gypsum board using aerosolized chemical agents
Authors: Wagner Andrew , Hoffman Melissa , Green Christopher F , Barth Edward , Davidson Craig , Gibbs Shawn G , Scarpino Pasquale V
Published: February 2006

Aerosolized disinfectant use has appealing qualities for inactivation and remediation of biologically contaminated materials. Their ability to reach exterior and interior spaces of walls and difficult to access areas has potential as a simple and cost effective remediation technique. Stachybotrys chartarum was used as a test organism against four disinfectants: chlorine dioxide, sodium hypochlorite, thiabendazole, and cupric sulfate – sodium hydroxide solution. Tests were conducted independently. The organism was exposed for 4 and 8 h periods to the aerosolized disinfectant. The building material was commercially available gypsum board with paper facing. This material was inoculated under sterile conditions. The commercially available treatments were administered as aerosols generated from a collison nebulizer directed into a sterile growth chamber housing inoculated gypsum board. Surface samples were collected before and after exposures to determine treatment effects. The aerosolized chlorine dioxide and sodium hypochlorite treatments successfully inactivated the organism after 8 h of continuous exposure. Key words: Stachybotrys chartarum, aerosolized disinfectant, gypsum board, fungi.
Plant-derived antifungal proteins and peptides
Authors: De Lucca A J , Cleveland T E , Wedge D E
Published: February 2006

Plants produce potent constitutive and induced antifungal compounds to complement the structural barriers to microbial infection. Approximately 250 000 – 500 000 plant species exist, but only a few of these have been investigated for antimicrobial activity. Nevertheless, a wide spectrum of compound classes have been purified and found to have antifungal properties. The commercial potential of effective plant-produced antifungal compounds remains largely unexplored. This review article presents examples of these compounds and discusses their properties.Key words: antifungal, peptides, phytopathogenic, plants, proteins.
Occurrence and growth characteristics ofEscherichia coliand enterococci within the accumulated fluid of the northern pitcher plant (Sarracenia purpureaL.)
Authors: Whitman Richard L , Byers Stacey E , Shively Dawn A , Ferguson Donna M , Byappanahalli Muruleedhara
Published: February 2006

Sarracenia purpurea L., a carnivorous bog plant (also known as the pitcher plant), represents an excellent model of a well-defined, self-contained ecosystem; the individual pitchers of the plant serve as a microhabitat for a variety of micro- and macro-organisms. Previously, fecal indicator bacteria (Escherichia coli and enterococci) were shown as incidental contaminants in pitcher fluid; however, whether their occurrence in pitcher fluid is incidental or common has not been established. The purpose of this study was to investigate the occurrence, distribution, and growth potential of E. coli and enterococci in pitcher plant fluid from a protected bog in northwest Indiana. Escherichia coli and enterococci were recovered in pitcher fluids (n = 43 plants), with mean densities (log CFU mL–1) of 1.28 ± 0.23 and 1.97 ± 0.27, respectively. In vitro experiments showed that E. coli growth in fluid not containing insects or indigenous organisms was directly proportional to the fluid concentration (growth was 10-fold in 24 h in 100% fluid); however, in the presence of other indigenous organisms, E. coli and enterococci were only sustained for 5 days at 26 °C. Pulsed-field gel electrophoresis (PFGE) analysis showed that the plant Enterococcus faecalis isolates were genetically distinct from the human isolates; identical PFGE patterns were observed among plant isolates that fell into one of six clonal groups. These findings suggest that (i) E. coli and enterococci occurrence in pitcher plants is rather common in the bog studied, although their originating source is unclear, and (ii) the pitcher fluid contains adequate nutrients, especially carbon and energy sources, to promote the growth of indicator bacteria; however, under natural conditions, the biotic factors (e.g., competition for nutrients) may restrict their growth.Key words: indicator bacteria, environmental occurrence, microcosm, pitcher plant fluid, temperate bog.
DNA fingerprinting analysis ofPetromyces alliaceus(AspergillussectionFlavi)
Authors: McAlpin Cesaria E , Wicklow Donald T
Published: February 2006

The objective of this study was to evaluate the ability of the Aspergillus flavus pAF28 DNA probe to produce DNA fingerprints for distinguishing among genotypes of Petromyces alliaceus (Aspergillus section Flavi), a fungus considered responsible for the ochratoxin A contamination that is occasionally observed in California fig orchards. P. alliaceus (14 isolates), Petromyces albertensis (one isolate), and seven species of Aspergillus section Circumdati (14 isolates) were analyzed by DNA fingerprinting using a repetitive sequence DNA probe pAF28 derived from A. flavus. The presence of hybridization bands with the DNA probe and with the P. alliaceus or P. albertensis genomic DNA indicates a close relationship between A. flavus and P. alliaceus. Twelve distinct DNA fingerprint groups or genotypes were identified among the 15 isolates of Petromyces. Conspecificity of P. alliaceus and P. albertensis is suggested based on DNA fingerprints. Species belonging to Aspergillus section Circumdati hybridized only slightly at the 7.0-kb region with the repetitive DNA probe, unlike the highly polymorphic hybridization patterns obtained from P. alliaceus and A. flavus, suggesting very little homology of the probe to Aspergillus section Circum dati genomic DNA. The pAF28 DNA probe offers a tool for typing and monitoring specific P. alliaceus clonal populations and for estimating the genotypic diversity of P. alliaceus in orchards, vineyards, or crop fields.Key words: Aspergillus alliaceus, Circumdati, DNA probe, genotypic diversity, hybridization patterns, ochratoxin, Southern blot.
Eugenol-induced contractions of saponin-skinned fibers are inhibited by heparin or by a ryanodine receptor blocker
Authors: Lofrano-Alves Marco S. , Oliveira Edson L. , Damiani Carlos E.N. , Kassouf-Silva Ilana , Fogaça Rosalvo T.H.
Published: February 2006

The effects of eugenol on the sarcoplasmic reticulum (SR) and contractile apparatus of chemically skinned skeletal muscle fibers of the frog Rana catesbeiana were investigated. In saponin-skinned fibers, eugenol (5 mmol/L) induced muscle contractions, probably by releasing Ca2+from the SR. The Ca2+-induced Ca2+release blocker ruthenium red (10 μmol/L) inhibited both caffeine- and eugenol-induced muscle contractions. Ryanodine (200 μmol/L), a specific ryanodine receptor/Ca2+release channel blocker, promoted complete inhibition of the contractions induced by caffeine, but only partially blocked the contractions induced by eugenol. Heparin (2.5 mg/mL), an inositol 1,4,5-trisphosphate (InsP3) receptor blocker, strongly inhibited the contractions induced by eugenol but had only a small effect on the caffeine-induced contractions. Eugenol neither altered the Ca2+sensitivity nor the maximal force in Triton X-100 skinned muscle fibers. These data suggest that muscle contraction induced by eugenol involves at least 2 mechanisms of Ca2+release from the SR: one related to the activation of the ryanodine receptors and another through a heparin-sensitive pathway.
Régulation de la volémie au cours d’une simulation d’impesanteur de longue durée
Authors: Custaud Marc-Antoine , Belin de Chantemèle Éric , Blanc Stéphane , Gauquelin-Koch Guillemette , Gharib Claude
Published: February 2006

Pour étudier les effets de la microgravité sur les mécanismes de régulation de la volémie et de l’eau corporelle totale (ECT), les variations d’ECT, du volume plasmatique (VP) et des principales hormones intervenant dans la régulation de la volémie (rénine, aldostérone, peptide atrial natriurétique (ANP), hormone anti-diurétique (ADH)) ont été déterminées par dilution isotopique, formule de Dill et Costill et dosages radio-immunologiques, chez 9 hommes soumis à un alitement à –6° de 3 mois. Les osmolalités urinaires et plasmatiques, la natrémie, la kaliémie et les excrétions urinaires sodée et potassique ont aussi été mesurées. Pendant ces 3 mois, la masse des sujets (–2,8 ± 0,8 kg), l’eau totale (–7,2 % ± 0,9 % soit –2,6 ± 0,7 kg) et le VP (–4,7 % ± 1,8 %) ont diminué. La rénine plasmatique et l’aldostérone ont augmenté (+109,0 % ± 15,4 % et +87,2 % ± 38,9 % respectivement). L’ANP a diminué de –33,2 % ± 20,4 %. Les autres variables, dont l’ADH, n’ont pas changé. La baisse pondérale, la diminution de l’ECT et de la masse maigre s’expliquent vraisemblablement par une atrophie musculaire. L’élévation des facteurs de rétention sodée et l’inhibition de l’ANP s’expliquent par l’hypovolémie modérée, qui, sans variation de l’osmolalité plasmatique, semble incapable de stimuler la sécrétion d’ADH. Ce dernier fait démontre la primauté de l’osmolalité plasmatique dans la régulation de l’ADH.
Chunghyuldan activates NOS mRNA expression and suppresses VCAM-1 mRNA expression in human endothelial cells
Authors: Park Seong-Uk , Jung Woo-Sang , Moon Sang-Kwan , Ko Chang-Nam , Cho Ki-Ho , Kim Young-Suk , Bae Hyung-Sup , Chi Sung-Gil
Published: February 2006

Chunghyuldan (CHD), a combinatorial drug that has antihyperlipidemic and anti-inflammatory activities, has been shown to improve arterial stiffness and inhibit stroke recurrence in clinical study. To understand the molecular basis of CHD's clinical effects, we explored its effect on cell proliferation and expression of nitric oxide synthase (NOS) and vascular cell adhesion molecule (VCAM-1) in human umbilical vein endothelial cells (HUVECs). Cell number counting and [3H]thymidine incorporation assay demonstrated that nontoxic doses of CHD have an inhibitory effect on DNA synthesis and suppress cell cycle progression of HUVECs. CHD treatment led to a marked induction of NO production through up-regulation of NOS mRNA expression in a dose- and time-dependent manner, whereas it suppressed VCAM-1 expression. CHD inhibition of VCAM-1 expression was totally blocked by pretreatment with the NO synthesis inhibitor L-NMMA, whereas pretreatment with the NO donor DETA-NO further decreased VCAM-1 level in CHD-treated HUVECs, indicating that VCAM-1 regulation by CHD is mediated through increased NO synthesis by CHD. In addition, TNF-α-mediated VCAM-1 activation was substantially impeded by CHD treatment. Collectively, our data suggest that anti-inflammatory or anti-hyperlipidemic effects of CHD might be associated with its ability to activate NO production and suppress VCAM-1 expression in human endothelial cells.
The α1-adrenergic receptor not the DA1-dopaminergic receptor mediates cyclosporine–SKF38393 renovascular interaction
Authors: El-Mas Mahmoud M. , El-Din Mahmoud M. Mohy , El-gowilly Sahar M. , Sharabi Fouad M.
Published: February 2006

In this study, we investigated the effect of acute exposure to cyclosporine A (CyA) on renal vasodilations evoked by the DA1 dopaminergic agonist SKF38393 and whether dopamine DA1 receptors are directly involved in the interaction. Changes evoked by CyA in SKF38393 vasodilations were evaluated in phenylephrine-preconstricted isolated perfused rat kidneys in the absence and presence of SCH23390, a DA1 receptor antagonist. SKF38393 (3 × 10–8 to 3 × 10–6 mol) produced dose-dependent reductions in the renal perfusion pressure that were significantly attenuated in tissues pretreated with SCH23390 or CyA. Unlike SKF38393, the vasodilatory action of sodium nitroprusside, a nitrovasodilator, was not altered by CyA. The attenuating effect of CyA on SKF38393 vasodilations was preserved in preparations pretreated with SCH23390, suggesting that sites other than DA1 receptors may be involved in CyA–SKF38393 interaction. The study was then extended to investigate the possible involvement of renal α1-adrenoceptors in the interaction. Blockade of α1-adrenoceptors by prazosin (30 nmol/L) significantly reduced the vasodilatory effect of SKF38393 and virtually abolished the CyA-induced attenuation of SKF38393 responses. Further, CyA failed to alter SKF38393 vasodilations when the renal tone was raised with prostaglandin F2α (PGF2α), a vasoconstrictor whose effect is independent of α1-adenoceptors. Together, these findings support earlier reports that both DA1 and α1-receptors mediate the renal vasodilatory action of SKF38393 and suggest that CyA interacts selectively with the α1-receptor component to compromise SKF38393 responses.
Glyceryl trinitrate-induced angiotensin-converting enzyme (ACE) inhibition in healthy volunteers is dependent on ACE genotype
Authors: Persson Karin , Säfholm Annette C.E. , Andersson Rolf G.G. , Ahlner Johan
Published: February 2006

Evidence concerning the importance of angiotensin-converting enzyme (ACE) genotype in cardiovascular diseases is accumulating. The aim of this study was to investigate if nitric oxide (NO), generated from glyceryl trinitrate (GTN), affects human serum ACE activity in vivo, and if so, whether this effect was dependent on ACE genotype and (or) reflected in blood pressure reduction. A tablet containing 5 mg GTN was bucally administered for 5 minutes to 17 healthy volunteers. Blood pressure (BP) was recorded, and serum ACE activity, ACE genotype, and plasma cGMP was analyzed. GTN administration significantly reduced BP only in individuals with the deletion/deletion (DD) genotype. Sixty minutes after GTN administration, serum ACE activity was reduced in individuals with the insertion/insertion (II) and insertion/deletion (ID) genotypes, but not the DD genotype. Comparing the change in ACE activity over time between the genotypes resulted in the following: II vs. DD, p < 0.01; II vs. ID, p < 0.05; and ID vs. DD, p < 0.05. There was no significant difference in plasma cGMP content neither between the ACE genotypes nor before and after GTN administration. In conclusion, GTN inhibits serum ACE in vivo in individuals with the II and ID, but not the DD genotype.
TWO-FIELD MODELS OF DARK ENERGY WITH EQUATION OF STATE ACROSS -1
Authors: ZHANG XIAO-FEI , LI HONG , PIAO YUN-SONG , ZHANG XINMIN
Published: February 2006

In this paper, we study the possibility of building two-field models of dark energy with equation of state across -1. Specifically we will consider two classes of models: one consists of two scalar fields (quintessence + phantom) and another includes one scalar (phantom) and one spinor field (neutrino). Our studies indicate to some extent that two-field models give rise to a simple realization of the dynamical dark energy model with the equation of state across w=-1.
THE HIGGS SECTOR AND ELECTRON ELECTRIC DIPOLE MOMENT IN NEXT-TO-MINIMAL SUPERSYMMETRY WITH EXPLICIT CP VIOLATION
Authors: BOZ MÜGE
Published: February 2006

We study the explicit CP violation of the Higgs sector in the next-to-minimal supersymmetric model with a gauge singlet Higgs field. Our numerical predictions show that electric dipole moment of electron lies around the present experimental upper limits. The mass of the lightest Higgs boson is quite sensitive to the CP violating phases in the theory. It is observed that as the vacuum expectation value of the singlet gets higher values, CP violation increases.
D-BRANE WORLDS AND THE COSMOLOGICAL CONSTANT
Authors: GUSIN P. , WARCZEWSKI J.
Published: February 2006

The cosmological constant on a D-brane is analyzed. This D-brane is in the background produced by the p-brane solutions. The energy–momentum tensor in this model has been found and the form of the cosmological constant has been derived. This energy–momentum tensor is interpreted as an energy–momentum tensor for a perfect fluid on the D-brane. The energy density and the pressure for this fluid have been derived. As it turned out the pressure is negative but the speed of sound is real.
LOCAL DEMANDS ON STERILE NEUTRINOS
Authors: LATIMER D. C. , ERNST D. J.
Published: February 2006

In a model-independent manner, we explore the local implications of a single neutrino oscillation measurement which cannot be reconciled within a three-neutrino theory. We examine this inconsistency for a single region of baseline to neutrino energy L/E. Assuming that sterile neutrinos account for the anomaly, we find that the local demands of this datum can require the addition to the theory of one to three sterile neutrinos. We examine the constraints which can be used to determine when more than one neutrino would be required. The results apply only to a given region of L/E. The question of the adequacy of the sterile neutrinos to satisfy a global analysis is not addressed here. Finally, using the results of a 3+2 analysis, we indicate values for unknown mixing matrix elements which would require two sterile neutrinos due to local demands only.
A NONCRITICAL RAMOND–NEVEU–SCHWARZ STRING WITH ONE END FIXED
Authors: ARAPOGLU SAVAŞ , SAÇLIOGLU CIHAN
Published: February 2006

We study a Ramond–Neveu–Schwarz string with one end fixed on a D0-brane and the other end free as a qualitative guide to the spectrum of hadrons containing one very heavy quark. The mixed boundary conditions break half of the worldsheet supersymmetry and allow only odd α and even d modes in the Ramond sector, while the Neveu–Schwarz oscillators b's become odd-integer moded. Boson-fermion masses can still be matched if space–time is nine-dimensional; thus SO(8) triality still plays a role in the spectrum, although full space–time supersymmetry does not survive. We quantize the system in a temporal-like gauge where X0 ~ τ. Although the gauge choice eliminates negative-norm states at the outset, there are still even-moded Virasoro and even (odd) moded super-Virasoro constraints to be imposed in the NS(R) sectors. The Casimir energy is now positive in both sectors; there are no tachyons. States for α′ M2 ≤ 13/4 are explicitly constructed and found to be organized into SO(8) irreps by (super)constraints, which include a novel "[Formula: see text]" operator in the Neveu–Schwarz and Γ0 ± I in the Ramond sectors. GSO projections are not allowed. The preconstraint states above the ground state have matching multiplicities, indicating space–time supersymmetry is broken by the (super)constraints. A distinctive physical signature of the system is a slope twice that of the open RNS string. When both ends are fixed, all leading and subleading trajectories are eliminated, resulting in a spectrum qualitatively similar to the J/ψ and ϒ particles.
IMPROVED STABILITY FOR PULSATING MULTISPIN STRING SOLITONS
Authors: KHAN A. , LARSEN A. L.
Published: February 2006

We derive and analyze, analytically and numerically, the equations for perturbations around the pulsating two-spin string soliton in AdS 5×S5. We show that the pulsation in S5 indeed improves the stability properties of the two-spin string soliton in AdS 5, in the sense that the more pulsation we have, the higher spin we can allow and still have stability.
OPERATOR ORDERING AND CLASSICAL SOLITON PATH IN TWO-DIMENSIONAL N = 2 SUPERSYMMETRY WITH KÄHLER POTENTIAL
Authors: MOTOYUI NOBUYUKI , YAMADA MITSURU
Published: February 2006

We investigate a two-dimensional N = 2 supersymmetric model which consists of n chiral superfields with Kähler potential. When we define quantum observables, we are always plagued by operator ordering problem. Among various ways to fix the operator order, we rely upon the supersymmetry. We demonstrate that the correct operator order is given by requiring the super-Poincaré algebra by carrying out the canonical Dirac bracket quantization. This is shown to be also true when the supersymmetry algebra has a central extension by the presence of topological soliton. It is also shown that the path of soliton is a straight line in the complex plane of superpotential W and triangular mass inequality holds. One half of supersymmetry is broken by the presence of soliton.
EINSTEIN'S GRAVITATIONAL LENSING AND NONLINEAR ELECTRODYNAMICS
Authors: CUESTA HERMAN J. MOSQUERA , SALIM JOSÉ M. , DE FREITAS PACHECO JOSÉ A.
Published: February 2006

Einstein (1936) predicted the phenomenon presently known as gravitational lensing (GL). A prime feature of GL is the magnification, because of the gravitational field, of the star visible surface as seen from a distant observer. We show here that nonlinear electrodynamics (NLED) modifies in a fundamental basis Einstein's general relativistic (GR) original derivation. The effect becomes apparent by studying the light propagation from a strongly magnetic (B) pulsar (SMP). Unlike its GR counterpart, the photon dynamics in NLED leads to a new effective GL, which depends also on the B-field permeating the pulsar. The apparent radius of a SMP appears then unexpectedly diminished, by a large factor, as compared to the classical Einstein's prediction. This may prove very crucial in determining physical properties of high B-field stars from their X-ray emission.
CHARMLESS WEAK DECAYS OF Λb BARYON
Authors: KAUR HARPREET , KHANNA M. P.
Published: February 2006

Two-body nonleptonic charmless weak decays of Λb baryon involving p (or Λ) have been discussed. The form factors for various transitions are calculated in the nonrelativistic quark model, based on factorization assumption.
NOVEL SOUND PHENOMENA IN IMPURE SUPERFLUIDS
Authors: BRUSOV PETER , BRUSOV PAVEL
Published: February 2006

In the last decade, new techniques for producing impure superfluids with unique properties have been developed. This new class of systems includes superfluid helium confined to aerogel, HeII with different impurities, superfluids in Vycor glasses, and watergel. These systems exhibit very unusual properties including unexpected acoustic features. We discuss the sound properties of these systems and show that sound phenomena in impure superfluids are modified from those in pure superfluids.

We calculate the coupling between temperature and pressure oscillations for impure superfluids and show that this coupling increases significantly. This leads to the existence in impure superfluids of such unusual sound phenomena as slow "pressure" waves and fast "temperature" waves. This also decreases the threshold values for nonlinear processes as compared to pure superfluids. Sound conversion, which has been observed in pure superfluids only by high intensity waves should be observed at moderate sound amplitude in impure superfluids. Cerenkov emission of second sound by first sound (which has never been observed in superfluids) could be observed in impure superfluids. Even the nature of the sound modes in impure superfluids turns out to be changed. We have also derived for the first time the nonlinear hydrodynamic equations for superfluid helium in aerogel.
LONG-TERM RATES OF FAULTING DERIVED FROM COSMOGENIC NUCLIDES AND SHORT-TERM VARIATIONS CAUSED BY GLACIAL-INTERGLACIAL VOLUME CHANGES OF GLACIERS AND LAKES
Authors: HETZEL RALF , HAMPEL ANDREA
Published: February 2006

Seismic hazard evaluations on major faults in Earth's crust are based on their slip histories, which reflect the frequency of earthquakes that ruptured a fault in the past. On a 100 000-year timescale, the slip rate of a fault can be determined by dating geomorphic surfaces that are offset by a fault. Application of this method to alluvial fan surfaces and river terraces offset by thrust faults in Tibet yields long-term slip rates of less than 1mm/a. Slip rates on a 10 000-year timescale are derived from paleoseismologic data and document that faults experience considerable slip rate variations on timescales of 100 to 1000 years. In particular, slip rates are often considerable higher in the present interglacial, the Holocene, than during the last glacial period, the Late Pleistocene. The causes of this behavior have remained enigmatic but their assessment is essential for an accurate evaluation of a fault's past and future seismicity. Numerical experiments show that the retreat of lakes and glaciers at the end of the last glacial period can cause an increase in the Holocene slip rate of a fault. Such a correlation between enhanced seismicity and climate-driven mass fluctuations on Earth's surface is best documented for the Wasatch Fault, Utah.
TRANSPORT EQUATIONS FROM LIOUVILLE EQUATIONS FOR FRACTIONAL SYSTEMS
Authors: TARASOV VASILY E.
Published: February 2006

We consider dynamical systems that are described by fractional power of coordinates and momenta. The fractional powers can be considered as a convenient way to describe systems in the fractional dimension space. For the usual space the fractional systems are non-Hamiltonian. Generalized transport equation is derived from Liouville and Bogoliubov equations for fractional systems. Fractional generalization of average values and reduced distribution functions are defined. Gasdynamic equations for fractional systems are derived from the generalized transport equation.
STRUCTURAL AND DILATOMETRIC PROPERTIES OF LANTHANUM-SUBSTITUTED PCT CERAMICS
Authors: SINGH SARABJIT , THAKUR O. P. , PRAKASH CHANDRA , RAINA K. K.
Published: February 2006

Pb 0.76-3x/2 La x Ca 0.24 Mn 0.02 Ti 0.98 O 3 ( PLCT ), x=0–0.08 (in steps of 0.02), ceramics were prepared by conventional mixed oxide technique. The samples were sintered at an optimized temperature of 1150°C. Phase and microstructural analysis were carried out using X-ray Diffraction (XRD) and scanning electron microscope (SEM) to study the effect of lanthanum on PCT ceramics. Both experimental and theoretical densities for all the samples were also determined. Phase analysis shows the single-phase material with tetragonal structure and the decrease in tetragonality is observed with the increase in the amount of lanthanum in the base composition. Detailed dilatometric investigations were performed in order to study the shrinkage behaviour and dominating shrinkage mechanism in the present system.
REMARKS ON SKEW PRODUCTS OVER IRRATIONAL ROTATIONS
Authors: LERMAN L. M.
Published: February 2006

We prove several results of the orbit behavior of skew product diffeomorphisms generated by quasi-periodic differential systems. The first diffeomorphism is derived from a periodic differential equation on the circle by means of a construction proposed by Z. Opial to get a scalar quasi-periodic equation with all its solutions bounded but without an almost periodic solution. We consider both possible cases for the irrational rotation number, transitive and singular (intransitive). The main result for a transitive case is that the related skew product diffeomorphism has a foliation into invariant curves with pure irrational rotation on each curve (being the same for each curve). For intransitive case, we get invariant sets of two types: a collection of continuous invariant curves and invariant sets being dimensionally inhomogeneous ones.

Section 3 is devoted to perturbations of a skew product diffeomorphism over an irrational rotation being initially foliated into invariant curves. We prove an analog of Poincaré–Pontryagin theorem which sets conditions when a perturbation of a one-degree-of-freedom Hamiltonian system (given in an annulus and written down in action-angle variables) has limit cycles. Our theorem provides sufficient conditions when a perturbation of a foliated skew product diffeomorphism has isolated invariant curves (asymptotically stable or unstable).

In Sec. 4 we present some results on the geometry of skew product diffeomorphisms derived by a quasi-periodic Riccati equation.
SYNCHRONIZATION AND GRAPH TOPOLOGY
Authors: BELYKH IGOR , HASLER MARTIN , LAURET MENNO , NIJMEIJER HENK
Published: February 2006

This paper clarifies the relation between synchronization and graph topology. Applying the Connection Graph Stability method developed by Belykh et al. [2004a] to the study of synchronization in networks of coupled oscillators, we show which graph properties matter for synchronization. In particular, while we explicitly link the stability of synchronization with the average path length for a wide class of coupling graphs, we prove by a simple argument that the average path length is not always the crucial quantity for synchronization. We also show that synchronization in scale-free networks can be described by means of regular networks with a star-like coupling structure. Finally, by considering an example of coupled Hindmarsh–Rose neuron models, we demonstrate how global stability of synchronization depends on the parameters of the individual oscillator.
CHAOTIC ATTRACTOR IN THE KURAMOTO MODEL
Authors: MAISTRENKO YURI L. , POPOVYCH OLEKSANDR V. , TASS PETER A.
Published: February 2006

The Kuramoto model of globally coupled phase oscillators is an essentially nonlinear dynamical system with a rich dynamics including synchronization and chaos. We study the Kuramoto model from the standpoint of bifurcation and chaos theory of low-dimensional dynamical systems. We find a chaotic attractor in the four-dimensional Kuramoto model and study its origin. The torus destruction scenario is one of the major mechanisms by which chaos arises. L. P. Shilnikov has made decisive contributions to its discovery. We show also that in the Kuramoto model the transition to chaos is in accordance with the torus destruction scenario. We present the general bifurcation diagram containing phase chaos, Cherry flow as well as periodic and quasiperiodic dynamics.
THREE-DIMENSIONAL HÉNON-LIKE MAPS AND WILD LORENZ-LIKE ATTRACTORS
Authors: GONCHENKO S. V. , OVSYANNIKOV I. I. , SIMÓ C. , TURAEV D.
Published: February 2006

We discuss a rather new phenomenon in chaotic dynamics connected with the fact that some three-dimensional diffeomorphisms can possess wild Lorenz-type strange attractors. These attractors persist for open domains in the parameter space. In particular, we report on the existence of such domains for a three-dimensional Hénon map (a simple quadratic map with a constant Jacobian which occurs in a natural way in unfoldings of several types of homoclinic bifurcations). Among other observations, we have evidence that there are different types of Lorenz-like attractor domains in the parameter space of the 3D Hénon map. In all cases the maximal Lyapunov exponent, Λ1, is positive. Concerning the next Lyapunov exponent, Λ2, there are open domains where it is definitely positive, others where it is definitely negative and, finally, domains where it cannot be distinguished numerically from zero (i.e. |Λ2| < ρ, where ρ is some tolerance ranging between 10-5 and 10-6). Furthermore, several other types of interesting attractors have been found in this family of 3D Hénon maps.
A PHENOMENOLOGICAL APPROACH TO NORMAL FORM MODELING: A CASE STUDY IN LASER INDUCED NEMATODYNAMICS
Authors: TONIOLO C. , RUSSO G. , RESIDORI S. , TRESSER C.
Published: February 2006

An experimental setting for the polarimetric study of optically induced dynamical behavior in nematic liquid crystal films presented by G. Cipparrone, G. Russo, C. Versace, G. Strangi and V. Carbone allowed to identify most notably some behavior which was recognized as gluing bifurcations leading to chaos. This analysis of the data used a comparison with a model for the transition to chaos via gluing bifurcations in optically excited nematic liquid crystals previously proposed by G. Demeter and L. Kramer. The model of these last authors, relying on the original model for chaos by cascade of gluing bifurcations proposed by A. Arneodo, P. Coullet and C. Tresser about twenty years before, does not have the central symmetry which one would expect for minimal dimensional model for chaos in nematics in view of the time series near the gluing bifurcation. What we show here is that the simplest truncated normal forms for gluing with the appropriate symmetry and minimal dimension do exhibit time signals that are embarrassingly similar to the ones that could be found using the above-mentioned experimental settings. It so happens that the gluing bifurcation scenario itself is only visible in limited parameter ranges, and that a substantial aspect of the chaos that can be observed is due to other factors. First, out of the immediate neighborhood of the homoclinic curve, nonlinearity can produce expansion which easily produces chaos when combined with the recurrence induced by the homoclinic behavior. Also, pairs of symmetric homoclinic orbits create extreme sensitivity to noise, so that when the noiseless approach to attracting homoclinic pairs contains a rich behavior, minute noise can transform the complex damping into sustained chaos. As Leonid Shilnikov has taught us, combining global considerations and local spectral analysis near critical points is crucial to understand the phenomenology associated to homoclinic bifurcations in dissipative systems. We see here on an example how this helps construct a phenomenological approach to modeling experiments in nonlinear dissipative contexts.
HYPERBOLIC PLYKIN ATTRACTOR CAN EXIST IN NEURON MODELS
Authors: BELYKH VLADIMIR , BELYKH IGOR , MOSEKILDE ERIK
Published: February 2006

Strange hyperbolic attractors are hard to find in real physical systems. This paper provides the first example of a realistic system, a canonical three-dimensional (3D) model of bursting neurons, that is likely to have a strange hyperbolic attractor. Using a geometrical approach to the study of the neuron model, we derive a flow-defined Poincaré map giving an accurate account of the system's dynamics. In a parameter region where the neuron system undergoes bifurcations causing transitions between tonic spiking and bursting, this two-dimensional map becomes a map of a disk with several periodic holes. A particular case is the map of a disk with three holes, matching the Plykin example of a planar hyperbolic attractor. The corresponding attractor of the 3D neuron model appears to be hyperbolic (this property is not verified in the present paper) and arises as a result of a two-loop (secondary) homoclinic bifurcation of a saddle. This type of bifurcation, and the complex behavior it can produce, have not been previously examined.
BIFURCATIONAL FEATURES IN SYSTEMS OF NONLINEAR PARABOLIC EQUATIONS WITH WEAK DIFFUSION
Authors: KASCHENKO S. A.
Published: February 2006

Asymptotic solutions of parabolic boundary value problems are studied in a neighborhood of both an equilibrium state and a cycle in near-critical cases which can be considered as infinite-dimensional due to small values of the diffusion coefficients. Algorithms are developed to construct normalized equations in such situations. Principle difference between bifurcations in two-dimensional and one-dimensional spatial systems is demonstrated.
CHAOTIC DYNAMICS OF A SPATIO-INHOMOGENEOUS MEDIUM
Authors: ANISHCHENKO V. S. , VADIVASOVA T. E. , OKROKVERTSKHOV G. A. , AKOPOV A. A. , STRELKOVA G. I.
Published: February 2006

In the present paper we show that inhomogeneity of a continuous self-sustained oscillating medium can be a reason for the onset of chaotic behavior. It has been established that temporal chaotic dynamics typically arises in the medium with a linear mismatch of the natural frequency along a spatial coordinate, whereas a chaotic regime is not characteristic for the medium with randomly distributed frequencies. The interconnection has been revealed between the temporal chaotic behavior and the spatial formation of imperfect clusters. The spectral and correlation analysis as well as the linear analysis of stability of regular and chaotic regimes in the inhomogeneous medium are performed. The correlation of the instantaneous phase dynamics of oscillations with the behavior of autocorrelation functions has been examined. It has been established that the characteristics of temporal chaos correspond to a spiral attractor (Shilnikov's attractor).
ROOTS AND CENTRALIZERS OF ANOSOV DIFFEOMORPHISMS ON TORI
Authors: FIEDLER BERNOLD
Published: February 2006

The centralizer of a group element g is the group of elements commuting with g. Powers and, if existent, roots of g are contained in the centralizer. We call a centralizer trivial if it consists of the integer powers of g, only.

In the group of torus homeomorphisms, we study the centralizer of torus diffeomorphisms of hyperbolic Anosov type. As a result, the centralizer can be calculated, isomorphically, in the much smaller group of affine torus automorphisms. In particular, Anosov diffeomorphisms of the 2-torus with a unique fixed point possess trivial centralizer, up to a trivial involution.

The identification of individual reactors from data on reactor cascades, for example in chemical engineering, is one source of motivation for the study of roots of diffeomorphisms. Another possible source is the study of commuting diffeomorphisms in finite-dimensional spatially or spatio-temporally chaotic systems.
HUMAN–HUMANOID INTERACTION: IS A HUMANOID ROBOT PERCEIVED AS A HUMAN?
Authors: OZTOP ERHAN , FRANKLIN DAVID W. , CHAMINADE THIERRY , CHENG GORDON
Published: February 2006

As humanoid robots become more commonplace in our society, it is important to understand the relation between humans and humanoid robots. In human face-to-face interaction, the observation of another individual performing an action facilitates the execution of a similar action, and interferes with the execution of a different action. This phenomenon has been explained by the existence of shared neural mechanisms for the execution and perception of actions, which would be automatically engaged by the perception of another individual's action. In one interference experiment, null interference was reported when subjects observed a robotic arm perform the incongruent task, suggesting that this effect may be specific to interacting with other humans. This experimental paradigm, designed to investigate motor interference in human interactions, was adapted to investigate how similar the implicit perception of a humanoid robot is to a human agent. Subjects performed rhythmic arm movements while observing either a human agent or humanoid robot performing either congruent or incongruent movements. The variance of the executed movements was used as a measure of the amount of interference in the movements. Both the human and humanoid agents produced a significant interference effect. These results suggest that observing the action of humanoid robots and human agents may rely on similar perceptual processes. Our findings suggest that experimental paradigms adopted from cognitive psychology can be used to derive measures for quantifying the degree of the implicit perception of a robot as human.
HAPTIC DETECTION OF OBJECT AFFORDANCES BY A MULTI-FINGERED ROBOT HAND
Authors: KUNIYOSHI YASUO , FUKANO RYO , OTANI TAKUYA , KOBAYASHI TAKUMI , OTSU NOBUYUKI
Published: February 2006

This paper proposes a learning method for detecting object affordances through haptic exploration by a multi-fingered robot hand. Learning how to remove a screw cap from a bottle is the present target task. Assuming that coarse manipulation strategy is given by other methods, such as visual observation of a model task, the system applies coarse grabbing actions to the target object. In response to the exploratory actions, the object moves (rotates, in this case) along the physical constraint (screw). The robot detects the resulting motion through proprioception of the compliant fingers. A non-supervised statistical learning method is applied to categorize the resulting motion. The method is a combination of high-order local autocorrelation (HLAC), principal components analysis (PCA), and mean-shift clustering. Experiments with a real multi-fingered robot hand and bottle caps of different diameters confirm that the proposed method can detect and categorize rotational constraints.
DEVELOPMENT OF HUMANOID ROBOT PLATFORM KHR-2 (KAIST HUMANOID ROBOT 2)
Authors: PARK ILL-WOO , KIM JUNG-YUP , PARK SEO-WOOK , OH JUN-HO
Published: February 2006

The mechanical and electrical system designs and system integration including controllers and sensory devices of the humanoid KHR-2 are presented. The design concept and the objective are also discussed. Since 2003, we have been developing KHR-2, which has 41 DOF (degrees of freedom). Each arm of KHR-2 has 11 DOF in total: 5 DOF/hand (i.e. fingers), 2 DOF/wrist, and 4 DOF/arm. Each leg constitutes 6 DOF. The head constitutes 6 DOF (2 DOF for eyes and 2 DOF at the neck), and the trunk has 1 DOF. KHR-2 has been mechanically designed to have a human friendly appearance and also wide ranges of angular motion. Its joint actuators have been designed in order to reduce motion uncertainties such as backlash. All axes of KHR-2 are under distributed control, which reduces the computational burden on the main controller and also to facilitate device expansions. We have developed a microprocessor-based sub-controller for servo motor operations, onto which sensory feedback is interfaced. The main controller, which is mounted on the back of the robot communicates with sub-controllers in real-time through CAN (Controller Area Network). Windows XP is used as the OS (Operating System), which enables rapid program development. RTX (Real Time eXtension) HAL extension software is used to realize the real-time control in the Windows XP environment. KHR-2 has several sensor types such as 3-axis F/T (Force/Torque) sensors at the foot and wrist, an inertia sensor system (accelerometer and rate gyro), and a CCD camera. The F/T sensor at the foot is crucially important for stable walking. The inertia sensor system is essential for determining the inclination of the robot with respect to the ground.
WHOLE-BODY COOPERATIVE BALANCED MOTION GENERATION FOR REACHING
Authors: NISHIWAKI KOICHI , KUGA MAMORU , KAGAMI SATOSHI , INABA MASAYUKI , INOUE HIROCHIKA
Published: February 2006

This paper addresses a construction method of a system that realizes whole body reaching motion of humanoids. Humanoids have many redundant degrees of freedom for reaching, and even the base can be moved by making the robot step. Therefore, there are infinite final posture solutions for a final goal position of reaching, and there are also infinite solutions for reaching trajectories that realize a final reaching posture. It is, however, difficult to find an appropriate solution because of the constraint of dynamic balance, and relatively narrow movable range for each joint. We prepared basic postures heuristically, and a final reaching posture is generated by modifying one of them. Heuristics, such as the fact that kneeling down is suitable for reaching near the ground, can be implemented easily by using this method. Methods that compose the reaching system, that is, basic posture selection, modification of postures for generating final reaching postures, balance compensation, footstep planning to realize desired feet position, and generation and execution of whole body motion to final reaching postures are described. Reaching to manually set positions and picking up a bat at various postures using visual information are shown as experiments to show the performance of the system.
Mappings and metaphors in auditory displays
Authors: Walker Bruce N. , Kramer Gregory
Published: February 2006

Auditory displays are becoming more and more common, but there are still no general guidelines for mapping data dimensions (e.g., temperature) onto display dimensions (e.g., pitch). This paper presents experimental research on different mappings and metaphors, in a generic process-control task environment, with reaction time and accuracy as dependent measures. It is hoped that this area of investigation will lead to the development of mapping guidelines applicable to auditory displays in a wide range of task domains.