bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat and Moisture Transport Through the Microclimate Air Annulus of the Clothing-Skin System Under Periodic Motion
Authors: Ghali K. , Ghaddar N. , Jaroudi E.
Published: September 2006

The study is concerned with the heat and moisture transport in a ventilated fabric-skin system composed of a microclimate air annulus that separates an outer cylindrical fabric boundary and an inner oscillating cylinder representing human skin boundary for open and closed aperture settings at the ends of the cylindrical system. The cylinder ventilation model of Ghaddar et al. (2005, Int. J. Heat Mass Transfer, 48(15), pp. 3151–3166) is modified to incorporate the heat and moisture transport from the skin when contact with fabric occurs at repetitive finite intervals during the motion cycle. During fabric skin contact, the heat and moisture transports are modeled based on the fabric dry and evaporative resistances at the localized touch regions at the top and bottom of points of the cylinder. Experiments were conducted to measure the mass transfer coefficient at the skin to the air annulus under periodic ventilation and to measure the sensible heat loss from the inner cylinder for the two cases of fabric-skin contact and no contact. The model predictions of time-averaged steady-periodic sensible heat loss agreed well with the experimentally measured values at different frequencies. The model results showed that the rate of heat loss increased with increased ventilation frequency at fixed (=amplitude/mean annular spacing). At amplitude factor of 1.4, the latent heat loss in the contact region increased by almost 40% compared to the loss at amplitude factor of 0.8 due to the increase in fabric temperature during contact. The sensible heat loss decreased slightly between 3% at f=60rpm and 5% at f=25rpm in the contact region due to higher air temperature and lack of heat loss by radiation when fabric and skin are in touch. The presence of an open aperture has a limited effect on increasing the total heat loss. For an open aperture system at amplitude factor of 1.4, the increase in heat loss over the closed apertures is 4.4%, 2.8%, and 2.2% at f=25, 40, and 60rpm, respectively.
Electronic Cooling Using Synthetic Jet Impingement
Authors: Pavlova Anna , Amitay Michael
Published: September 2006

The efficiency and mechanisms of cooling a constant heat flux surface by impinging synthetic jets were investigated experimentally and compared to cooling with continuous jets. Effects of jet formation frequency and Reynolds number at different nozzle-to-surface distances (H∕d) were investigated. High formation frequency (f=1200Hz) synthetic jets were found to remove heat better than low frequency (f=420Hz) jets for small H∕d, while low frequency jets are more effective at larger H∕d. Moreover, synthetic jets are about three times more effective in cooling than continuous jets at the same Reynolds number. Using particle image velocimetry, it was shown that the higher formation frequency jets are associated with breakdown and merging of vortices before they impinge on the surface. For the lower frequency jets, the wavelength between coherent structures is larger such that vortex rings impinge on the surface separately.
A Temperature Fourier Series Solution for a Hollow Sphere
Authors: Atefi Gholamali , Moghimi Mahdi
Published: September 2006

In this paper, we derive an analytical solution of a two-dimensional temperature field in a hollow sphere subjected to periodic boundary condition. The material is assumed to be homogeneous and isotropic with time-independent thermal properties. Because of the time-dependent term in the boundary condition, Duhamel’s theorem is used to solve the problem for a periodic boundary condition. The boundary condition is decomposed by Fourier series. In order to check the validity of the results, the technique was also applied to a solid sphere under harmonic boundary condition for which theoretical results were available in the literature. The agreement between the results of the proposed method and those reported by others for this particular geometry under harmonic boundary condition was realized to be very good, confirming the applicability of the technique utilized in the present work.
Film Cooling Effectiveness on the Leading Edge Region of a Rotating Turbine Blade With Two Rows of Film Cooling Holes Using Pressure Sensitive Paint
Authors: Ahn Jaeyong , Schobeiri M. T. , Han Je-Chin , Moon Hee-Koo
Published: September 2006

Detailed film cooling effectiveness distributions are measured on the leading edge of a rotating gas turbine blade with two rows (pressure-side row and suction-side row from the stagnation line) of holes aligned to the radial axis using the pressure sensitive paint (PSP) technique. Film cooling effectiveness distributions are obtained by comparing the difference of the measured oxygen concentration distributions with air and nitrogen as film cooling gas respectively and by applying the mass transfer analogy. Measurements are conducted on the first-stage rotor blade of a three-stage axial turbine at 2400rpm (positive off-design), 2550rpm (design), and 3000rpm (negative off-design), respectively. The effect of three blowing ratios is also studied. The blade Reynolds number based on the axial chord length and the exit velocity is 200,000 and the total to exit pressure ratio was 1.12 for the first-stage rotor blade. The corresponding rotor blade inlet and outlet Mach numbers are 0.1 and 0.3, respectively. The film cooling effectiveness distributions are presented along with discussions on the influence of rotational speed (off design incidence angle), blowing ratio, and upstream nozzle wakes around the leading edge region. Results show that rotation has a significant impact on the leading edge film cooling distributions with the average film cooling effectiveness in the leading edge region decreasing with an increase in the rotational speed (negative incidence angle).
Transient Response of Two-Phase Heat Exchanger With Varying Convection Coefficients
Authors: Naterer G. F. , Lam C. H.
Published: September 2006

Transient changes of fluid and wall temperatures in a two-phase heat exchanger are investigated in this article, particularly with respect to spatial and temporal effects of varying convection coefficients. The coupled energy equations for both sides of the heat exchanger are solved directly with an integral method. Varying convection coefficients are related to changes of vapor fraction between the inlet and outlet of the heat exchanger. Unlike past numerical studies encountering difficulties with instability, stiffness, and lack of convergence, the current integral formulation provides a reliable alternative and efficient procedure for transient response within the heat exchanger. Furthermore, complex inversion from a transformed domain is not needed, in contrast to conventional methods with Laplace transforms. In this article, past integral methods are extended to cases with varying convection coefficients, arising from changes of phase fraction on the two-phase side of the heat exchanger, as well a multiple step-changes of temperature. The predicted results show close agreement with past data, including numerical simulations with a dynamic simulator.
Energy Transport and Nanostructuring of Dielectrics by Femtosecond Laser Pulse Trains
Authors: Jiang Lan , Tsai Hai-Lung
Published: September 2006

This study analyzes single burst ablation of dielectrics by a femtosecond pulse train that consists of one or multiple pulses. It is found that (1) there exist constant-ablation-depth zones with respect to fluence for one or multiple pulses per train and (2) for the same total fluence per train, although the ablation depth decreases in multiple pulses as compared to that of a single pulse, the depth of the constant-ablation-depth zone decreases. In other words, repeatable structures at the desired smaller nanoscales can be achieved in dielectrics by using the femtosecond pulse train technology, even when the laser fluence is subject to fluctuations. The predicted trends are in agreement with published experimental data.
A potential carry-over effect in the measurement of induced loudness reduction
Authors: Epstein Michael , Gifford Elizabeth
Published: September 2006

The majority of studies on induced loudness reduction (ILR) use an experimental paradigm that results in an underestimation of the amount of ILR. Most of those studies utilize loudness matches between tones of two different frequencies (a test tone and a comparison tone) with (experimental condition) and without (baseline condition) an inducer tone at the test frequency. The change in level of the comparison tone between the baseline and experimental conditions is the amount of ILR. In those experiments, the level of the comparison tone in the baseline condition tends to be substantially higher (often about 10dB) than in the experimental condition. Because of this level difference, exposure to the baseline condition immediately prior to the experimental condition causes unintended ILR for the comparison tone. In this study, the delay between the baseline and experimental conditions was varied and it was determined that the amount of ILR is underestimated by about 30% and the variability is increased when the experimental condition is run immediately after the baseline condition. A second experiment using a Békésy-tracking procedure showed that ILR maximizes rapidly upon exposure to an inducer and decays over the course of several minutes after the inducer is removed.
Evidence against the mismatched interlanguage speech intelligibility benefit hypothesis
Authors: Stibbard Richard M. , Lee Jeong-In
Published: September 2006

In a follow-up study to that of Bent and Bradlow (2003), carrier sentences containing familiar keywords were read aloud by five talkers (Korean high proficiency; Korean low proficiency; Saudi Arabian high proficiency; Saudi Arabian low proficiency; native English). The intelligibility of these keywords to 50 listeners in four first language groups (Korean, n=10; Saudi Arabian, n=10; native English, n=10; other mixed first languages, n=20) was measured in a word recognition test. In each case, the non-native listeners found the non-native low-proficiency talkers who did not share the same first language as the listeners the least intelligible, at statistically significant levels, while not finding the low-proficiency talker who shared their own first language similarly unintelligible. These findings indicate a mismatched interlanguage speech intelligibility detriment for low-proficiency non-native speakers and a potential intelligibility problem between mismatched first language low-proficiency speakers unfamiliar with each others’ accents in English. There was no strong evidence to support either an intelligibility benefit for the high-proficiency non-native talkers to the listeners from a different first language background or to indicate that the native talkers were more intelligible than the high-proficiency non-native talkers to any of the listeners.
Outdoor sound propagation modeling in realistic environments: Application of coupled parabolic and atmospheric models
Authors: Lihoreau Bertrand , Gauvreau Benoit , Bérengier Michel , Blanc-Benon Philippe , Calmet Isabelle
Published: September 2006

Predicting long-range sound propagation over a nonurban site with complex propagation media requires the knowledge of micrometeorological fields in the lower part of the atmospheric boundary layer, and more precisely its characteristics varying in both space and time with respect to local (“small-scale”) and average (“long-term”) conditions, respectively. Thus in this study, a mean-wind wide-angle parabolic equation (MW-WAPE) code is coupled with a dedicated micrometeorological code (SUBMESO) which simulates wind and temperature fields over moderately complex terrain with high resolution. Its output data are used as input data for the MW-WAPE code, which can also deal with different boundary conditions, such as the introduction of impedance jumps, thin screens or complex topography. Both codes are presented in the present paper. Comparisons between numerical predictions, and experimental data are also presented and discussed. Finally, we present an example of such a coupling method (MW-WAPE/SUBMESO) for the estimation of sound pressure levels at almost any site (“local scale”), for mean propagation conditions representative of long-term atmospheric conditions.
Evaluation of layered multiple-scattering method for antiplane shear wave scattering from gratings
Authors: Cai Liang-Wu
Published: September 2006

The layered multiple-scattering method is based on an approximate solution for infinite gratings. In this method, an array of regularly arranged scatterers is viewed as comprising of layers of infinite grating and treated as a multiple transmission-reflection process in a multilayer panel. In this paper, this method is evaluated by comparing with exact solutions obtained by other means. One is a multiple-scattering solution. Another is the exact solution for an infinite grating, which is obtained by combining the T-matrix formulation of the multiple-scattering theory and an alternative representation of the Schlömilch series. The infinity nature enables the waves due to a planar incident wave to be expressed as planar waves and divided into propagating and evanescent modes. The layered multiple-scattering method accounts only for the propagating modes. Details of these modes are analyzed for a single grating, and it is concluded that only the first evanescent modes would have significant presence in a limited frequency range. The layered multiple-scattering method suggests that the only important geometric parameters for wave transmission and reflection are the grating distance and the interlayer distance. Numerical examples indicate that error due to evanescent modes might be significant due to interlayer interactions, such as critical frequencies of a stopband.
Spectral velocity estimation in ultrasound using sparse data sets
Authors: Jensen Jørgen Arendt
Published: September 2006

Velocity distributions in blood vessels can be displayed using ultrasound scanners by making a Fourier transform of the received signal and then showing spectra in an M-mode display. It is desired to show a B-mode image for orientation, and data for this have to be acquired interleaved with the flow data. This either halves the effective pulse repetition frequency fprf or gaps appear in the spectrum from B-mode emissions. This paper presents a technique to maintain the highest possible fprf and at the same time show a B-mode image. The power spectrum can be calculated from the Fourier transform of the autocorrelation function, and it is shown that the autocorrelation function can be calculated for a sparse set of data where flow and B-mode emissions are interspaced. Both short deterministic sequences of emissions and full random sequences can be used. The dynamic range of the sparse sequence is reduced compared to a full sequence. Typically, a reduction of 20dB is found when using 66% of the data compared to using all data. The theory of the method and examples from simulations of flow in arteries are presented. The audio signal can also be generated from the spectrogram.
A Combined Mitigation/Geoengineering Approach to Climate Stabilization
Authors: Wigley T. M. L.
Published: September 2006

Projected anthropogenic warming and increases in CO
2
concentration present a twofold threat, both from climate changes and from CO
2
directly through increasing the acidity of the oceans. Future climate change may be reduced through mitigation (reductions in greenhouse gas emissions) or through geoengineering. Most geoengineering approaches, however, do not address the problem of increasing ocean acidity. A combined mitigation/geoengineering strategy could remove this deficiency. Here we consider the deliberate injection of sulfate aerosol precursors into the stratosphere. This action could substantially offset future warming and provide additional time to reduce human dependence on fossil fuels and stabilize CO
2
concentrations cost-effectively at an acceptable level.
Mapping Essential Domains of
Mycobacterium smegmatis
WhmD: Insights into WhiB Structure and Function
Authors: Raghunand Tirumalai R. , Bishai William R.
Published: September 2006

A growing body of evidence suggests that the WhiB-like proteins exclusive to the GC-rich actinomycete genera play significant roles in pathogenesis and cell division. Each of these proteins contains four invariant cysteine residues and a conserved helix-turn-helix motif.
whmD
, the
Mycobacterium smegmatis
homologue of
Streptomyces coelicolor whiB
, is essential in
M. smegmatis
, and the conditionally complemented mutant
M. smegmatis
628-53 undergoes filamentation under nonpermissive conditions. To identify residues critical to WhmD function, we developed a cotransformation-based assay to screen for alleles that complement the filamentation phenotype of
M. smegmatis
628-53 following inducer withdrawal.
Mycobacterium tuberculosis whiB2
and
S. coelicolor whiB
complemented the defect in
M. smegmatis
628-53, indicating that these genes are true functional orthologues of
whmD
. Deletion analysis suggested that the N-terminal 67 and C-terminal 12 amino acid residues are dispensable for activity. Site-directed mutagenesis indicated that three of the four conserved cysteine residues (C
90
, C
93
, and C
99
) and a conserved aspartate (D
71
) are essential. Mutations in a predicted loop glycine (G
111
) and an unstructured leucine (L
116
) were poorly tolerated. The region essential for WhmD activity encompasses 6 of the 10 residues conserved in all seven
M. tuberculosis
WhiBs, as well as in most members of the WhiB family identified thus far. WhmD structure was found to be sensitive to the presence of a reducing agent, suggesting that the cysteine residues are involved in coordinating a metal ion. Iron-specific staining strongly suggested that WhmD contains a bound iron atom. With this information, we have now begun to comprehend the functional significance of the conserved sequence and structural elements in this novel family of proteins.
Flagella ofPyrococcus furiosus: Multifunctional Organelles, Made for Swimming, Adhesion to Various Surfaces, and Cell-Cell Contacts
Authors: Näther Daniela J. , Rachel Reinhard , Wanner Gerhard , Wirth Reinhard
Published: September 2006

Pyrococcus furiosus(“rushing fireball”) was named for the ability of this archaeal coccus to rapidly swim at its optimal growth temperature, around 100°C. Early electron microscopic studies identified up to 50 cell surface appendages originating from one pole of the coccus, which have been called flagella. We have analyzed these putative motility organelles and found them to be composed primarily (>95%) of a glycoprotein that is homologous to flagellins from other archaea. Using various electron microscopic techniques, we found that these flagella can aggregate into cable-like structures, forming cell-cell connections between ca. 5% of all cells during stationary growth phase.P. furiosuscells could adhere via their flagella to carbon-coated gold grids used for electron microscopic analyses, to sand grains collected from the original habitat (Porto di Levante, Vulcano, Italy), and to various other surfaces.P. furiosusgrew on surfaces in biofilm-like structures, forming microcolonies with cells interconnected by flagella and adhering to the solid supports. Therefore, we concluded thatP. furiosusprobably uses flagella for swimming but that the cell surface appendages also enable this archaeon to form cable-like cell-cell connections and to adhere to solid surfaces.
DRAWING WITH FAT EDGES
Authors: DUNCAN CHRISTIAN A. , EFRAT ALON , KOBOUROV STEPHEN , WENK CAROLA
Published: September 2006

Traditionally, graph drawing algorithms represent vertices as circles and edges as curves connecting the vertices. We introduce the problem of drawing with "fat" edges, i.e., with edges of variable thickness. The thickness of an edge is often used as a visualization cue, to indicate importance, or to convey some additional information. We present a model for drawing with fat edges and a corresponding efficient polynomial time algorithm that uses the model.

We first focus on a restricted class of graphs that occur in VLSI wire routing and then show how to extend the algorithm to general planar graphs. We show how to convert an arbitrary wire routing into a homotopically equivalent routing that maximizes the distance between any two wires, which is a desired property in VLSI design. Among such, we obtain the routing with minimum total wire length. A homotopically equivalent routing that maximizes the distance between any two wires yields a graph drawing which maximizes edge thickness. Our algorithm does not require unit edge thickness but can be applied as well in the presence of different edge weights.
ON THE COMPLEXITY OF COUNTING FIXED POINTS AND GARDENS OF EDEN IN SEQUENTIAL DYNAMICAL SYSTEMS ON PLANAR BIPARTITE GRAPHS
Authors: TOŠIĆ PREDRAG T.
Published: September 2006

We study counting various types of configurations in certain classes of graph automata viewed as discrete dynamical systems. The graph automata models of our interest are Sequential and Synchronous Dynamical Systems (SDSs and SyDSs, respectively). These models have been proposed as the mathematical foundation for a theory of large-scale simulations of complex multi-agent systems. Our emphasis in this paper is on the computational complexity of counting the fixed point and the garden of Eden configurations in Boolean SDSs and SyDSs. We show that counting these configurations is, in general, computationally intractable. We also show that this intractability still holds when both the underlying graphs and the node update rules of these SDSs and SyDSs are severely restricted. In particular, we prove that the problems of exactly counting fixed points, gardens of Eden and two other types of S(y)DS configurations are all #P-complete, even if the SDSs and SyDSs are defined over planar bipartite graphs, and each of their nodes updates its state according to a monotone update rule given as a Boolean formula. We thus add these discrete dynamical systems to the list of those problem domains where counting combinatorial structures of interest is intractable even when the related decision problems are known to be efficiently solvable.
GENERATION OF LANGUAGES BY REWRITING SYSTEMS THAT RESEMBLE AUTOMATA
Authors: KŘIVKA ZBYNĚK , MEDUNA ALEXANDER , SCHÖNECKER RUDOLF
Published: September 2006

This paper introduces and discusses #-rewriting systems, which represent language-generating devices that resemble automata by using finitely many states without any nonterminals. It demonstrates that these systems characterize the well-known infinite hierarchy of language families resulting from programmed grammars of finite index in a very natural way. In its conclusion, this paper suggests some variants of #-rewriting systems.
STEADY STATE FLUCTUATIONS OF THE DISSIPATED HEAT FOR A QUANTUM STOCHASTIC MODEL
Authors: DE ROECK WOJCIECH , MAES CHRISTIAN
Published: September 2006

We introduce a quantum stochastic dynamics for heat conduction. A multi-level subsystem is coupled to reservoirs at different temperatures. Energy quanta are detected in the reservoirs allowing the study of steady state fluctuations of the entropy dissipation. Our main result states a symmetry in its large deviation rate function.
THE GENERAL STRUCTURE OF G-GRADED CONTRACTIONS OF LIE ALGEBRAS, II: THE CONTRACTED LIE ALGEBRA
Authors: WEIMAR-WOODS EVELYN
Published: September 2006

We continue our study of G-graded contractions γ of Lie algebras where G is an arbitrary finite Abelian group. We compare them with contractions, especially with respect to their usefulness in physics. (Note that the unfortunate terminology "graded contraction" is confusing since they are, by definition, not contractions.)

We give a complete characterization of continuous G-graded contractions and note that they are equivalent to a proper subset of contractions. We study how the structure of the contracted Lie algebra Lγdepends on γ, and show that, for discrete graded contractions, applications in physics seem unlikely.

Finally, with respect to applications to representations and invariants of Lie algebras, a comparison of graded contractions with contractions reveals the insurmountable defects of the graded contraction approach. In summary, our detailed analysis shows that graded contractions are clearly not useful in physics.
THE ROLE OF POLARIZED VALONS IN THE FLAVOR SYMMETRY BREAKING OF NUCLEON SEA
Authors: MIRJALILI A. , TEHRANI S. ATASHBAR , KHORRAMIAN ALI N.
Published: September 2006

Next-to-leading order approximation of the quark helicity distributions are used in the framework of polarized valon model. The flavor-asymmetry in the light-quark sea of the nucleon can be obtained from the contributions of unbroken sea quark distributions. We employ the polarized valon model and extract the flavor-broken light sea distributions which are modeled with the help of a Pauli-blocking ansatz. Using this ansatz, we can obtain broken polarized valon distributions. From there and by employing convolution integral, broken sea quark distributions are obtainable in this framework. Our results for δu, δd, [Formula: see text] and [Formula: see text] are in good agreement with recent experimental data for polarized parton distribution from HERMES experimental group and also with GRSV model. Some information on orbital angular momentum as a main ingredient of total nucleon spin are given. The Q2 evolution of this quantity, using the polarized valon model is investigated.
QUANTUM PERFECT-FLUID KALUZA–KLEIN COSMOLOGY
Authors: HUANG WUNG-HONG , WANG I-CHIN
Published: September 2006

The perfect-fluid cosmology in the (1+d+D)-dimensional Kaluza–Klein space–times for an arbitrary barotropic equation of state p = (γ-1)ρ is quantized by using the Schutz's variational formalism. We make efforts in the mathematics to solve the problems in two cases. In the first case of the stiff fluid γ = 2 we exactly solve the Wheeler–DeWitt equation when the d space is flat. After the superposition of the solutions the wave-packet function is obtained exactly. We analyze the Bohmian trajectories of the final-stage wave-packet functions and show that the scale functions of the flat d spaces and the compact D spaces will eventually evolve into the nonzero finite values. In the second case of γ≈2, we use the approximated wave function in the Wheeler–DeWitt equation to find the analytic forms of the final-stage wave-packet functions. After analyzing the Bohmian trajectories we show that the flat d spaces will be expanding forever while the scale function of the contracting D spaces would not become zero within finite time. Our investigations indicate that the quantum effect in the quantum perfect-fluid cosmology could prevent the extra compact D spaces in the Kaluza–Klein theory from collapsing into a singularity or that the "crack-of-doom" singularity of the extra compact dimensions is made to occur at t = ∞.
A PERTURBATIVE REANALYSIS OF ${\mathcal N}=4$ SUPERSYMMETRIC YANG–MILLS THEORY
Authors: KOVACS STEFANO
Published: September 2006

The finiteness properties of the [Formula: see text] supersymmetric Yang–Mills theory are reanalyzed both in the component formulation and using [Formula: see text] superfields, in order to discuss some subtleties that emerge in the computation of gauge dependent quantities. The one-loop corrections to various Green functions of elementary fields are calculated. In the component formulation it is shown that the choice of the Wess–Zumino gauge, that is standard in supersymmetric gauge theories, introduces ultraviolet divergences in the propagators at the one-loop level. Such divergences are exactly canceled when the contributions of the fields that are put to zero in the Wess–Zumino gauge are taken into account. In the description in terms of [Formula: see text] superfields, infrared divergences are found for every choice of gauge different from the supersymmetric generalization of the Fermi–Feynman gauge. Two-, three- and four-point functions of [Formula: see text] superfields are computed and some general features of the infrared problem are discussed. We also examine the effect of the introduction of mass terms for the (anti)chiral superfields in the theory, which break supersymmetry from [Formula: see text] to [Formula: see text]. It is shown that in the mass deformed model no ultraviolet divergences appear in two-point functions. It is argued that this result can be generalized to n-point functions, supporting the proposal of a possible of use of this modified model as a supersymmetry-preserving regularization scheme for [Formula: see text] theories.
TOWARDS AN UNDERSTANDING OF NUCLEON SPIN STRUCTURE: FROM HARD TO SOFT SCALES
Authors: BASS STEVEN D. , AIDALA CHRISTINE A.
Published: September 2006

The workshop The Helicity Structure of the Nucleon (BNL June 5, 2006) was organized as part of the 2006 RHIC & AGS Users' Meeting to review the status of the spin problem and future directions. The presentations can be found at the workshop's website:1. Recent data suggest small polarized glue and strangeness in the proton. Here we present a personal summary of the main results and presentations. What is new and exciting in the data, and what might this tell us about the structure of the proton?
INTERMITTENCY OF MAGNETOHYDRODYNAMIC TURBULENCE: AN ASTROPHYSICAL PERSPECTIVE
Authors: LAZARIAN A.
Published: September 2006

Intermittency is an essential property of astrophysical fluids, which demonstrate an extended inertial range. As intermittency violates self-similarity of motions, it is impossible to naively extrapolate the properties of a fluid obtained computationally with relatively low resolution to the actual astrophysical situations. In terms of astrophysics, intermittency affects turbulent heating, momentum transfer, interaction with cosmic rays, radio waves and many more essential processes. Because of its significance, studies of intermittency call for coordinated efforts from both theorists and observers. In terms of theoretical understanding, we are still just scratching the surface of a very rich subject. We have some theoretically well-justified models that are poorly supported by experiments; we also have the She–Leveque model, which could be vulnerable on theoretical grounds, but, nevertheless, is well supported by experimental and laboratory data. We briefly discuss a rather mysterious property of turbulence called "extended self-similarity" and the possibilities that it opens up for the intermittency research. We then analyze simulations of MHD intermittency performed by different groups and show that their results do not contradict to each other. Finally, we discuss the intermittency of density, of turbulence in the viscosity-dominated regime as well as of polarization of Alfvenic modes. The latter provides an attractive solution to account for a slower cascading rate that is observed in some of the numerical experiments. We conclude by claiming that substantial progress in the field may be achieved by studies of turbulence intermittency via observations.
THE EVENT HORIZON OF THE SCHWARZSCHILD BLACK HOLE IN NONCOMMUTATIVE SPACES
Authors: NASSERI FOROUGH
Published: September 2006

The event horizon of the Schwarzschild black hole is obtained in noncommutative spaces up to the second order of perturbative calculations. Because this type of black hole is non-rotating, to the first order there is no effect on the event horizon due to the noncommutativity of space. A lower limit for the noncommutativity parameter is also obtained. As a result, the event horizon in noncommutative spaces is less than the event horizon in commutative spaces.
CANONICAL AND GRAVITATIONAL STRESS-ENERGY TENSORS
Authors: LECLERC M.
Published: September 2006

We deal with the question, under which circumstances the canonical Noether stress-energy tensor is equivalent to the gravitational (Hilbert) tensor for general matter fields under the influence of gravity. In the framework of general relativity, the full equivalence is established for matter fields that do not couple to the metric derivatives. Spinor fields are included into our analysis by reformulating general relativity in terms of tetrad fields, and the case of Poincaré gauge theory, with an additional, independent Lorentz connection, is also investigated. Special attention is given to the flat limit, focusing on the expressions for the matter field energy (Hamiltonian). The Dirac–Maxwell system is investigated in detail, with special care given to the separation of free (kinetic) and interaction (or potential) energy. Moreover, the stress-energy tensor of the gravitational field itself is briefly discussed.
CHECKING THE VARIABILITY OF THE GRAVITATIONAL CONSTANT WITH BINARY PULSARS
Authors: BISNOVATYI-KOGAN G. S.
Published: September 2006

The most precise measurements are obtained at present by timing of radiopulsars in binary systems with two neutron stars. The timing measurements of the Taylor–Hulse pulsar B1913+16 gave the most precise results on testing of general relativity (GR), finding implicit proof of existence of gravitational waves. We show that the available results of existing measurements, obtained to the year 1993, in combination with the results of the Mariner 10 in 1992, give the boundaries for the variation of the gravitational constant Ġ/G (within) the limits (-0.6 –+2) × 10-12 yr -1.
THERMAL EVOLUTION OF A RADIATING ANISOTROPIC STAR WITH SHEAR
Authors: NAIDU N. F. , GOVENDER M. , GOVINDER K. S.
Published: September 2006

We study the effects of pressure anisotropy and heat dissipation in a spherically symmetric radiating star undergoing gravitational collapse. An exact solution of the Einstein field equations is presented in which the model has a Friedmann-like limit when the heat flux vanishes. The behavior of the temperature profile of the evolving star is investigated within the framework of causal thermodynamics. In particular, we show that there are significant differences between the relaxation time for the heat flux and the relaxation time for the shear stress.
SCALAR GRAVITATIONAL WAVES FROM SCALAR-TENSOR GRAVITY: PRODUCTION AND RESPONSE OF INTERFEROMETERS
Authors: CAPOZZIELLO SALVATORE , CORDA CHRISTIAN
Published: September 2006

Scalar-tensor gravity admits the existence of scalar modes of gravitational waves (SGWs). The mechanism of production and the response of interferometers to these scalar components of gravitational waves can be studied in three different gauges in the massless case: the transverse-traceless (TT) gauge, the so-called "Shibata, Nakao and Nakamura" (SNN) gauge, and the local Lorentz gauge. The response of interferometers to massless SGWs is invariant in these different gauges. Our work generalizes previous results which, in the study of the coupling between interferometers and massless SGWs, started from the assumption that the wavelength of the SGW is much larger than the distance between the test masses. Furthermore, considering situations motivated by string-dilaton gravity, the effect of a small mass term on the response of the interferometer is taken into account. In this case (massive SGW), we have a longitudinal effect, the response of an arm of an interferometer, which is aligned in the wave propagation direction is computed. The value of the longitudinal response function for non-relativistic massive SGW at high frequencies is very high: this fact opens the doors to the interesting possibility of detection of "massive" part of the signal, if advanced projects will achieve high sensitivities. Finally, by using previous results and the geometry of the system, the generalized coupling between interferometers (like VIRGO or LIGO) and massless SGWs is studied. The total frequency response function to massless SGWs incoming from arbitrary directions is studied.
Modelling and Querying the Expressive Semantics of Dance Videos
Authors: Ramadoss Balakrishnan , Rajkumar Kannan
Published: September 2006

Dance videos are interesting and semantics-intensive. At the same time, they are complex type of videos, when compared to all other types such as sports, news and movie videos. In fact, dance video is the one which is less explored by the researchers across the globe. This paper presents a dance video data model to represent the semantics of the dance videos with different granularity levels, identified by the components of the accompanying song. Secondly, the paper proposes a multi-level index structure to efficiently handle containment, temporal, spatial and spatiotemporal query types. Moreover, the index structure has been designed to consider the queries with different levels of constraints. Finally, the paper presents the experimental results depicting the performance of different types of dance video queries.
Mining Frequent Fuzzy Grids in Dynamic Databases with Weighted Transactions and Weighted Items
Authors: Subramanyam R. B. V. , Goswami A.
Published: September 2006

Incremental mining algorithms that derive the latest mining output by making use of previous mining results are attractive to business organisations. In this paper, a fuzzy data mining algorithm for incremental mining of frequent fuzzy grids from quantitative dynamic databases is proposed. It extends the traditional association rule problem by allowing a weight to be associated with each item in a transaction and with each transaction in a database to reflect the interest/intensity of items and transactions. It uses the information about fuzzy grids that are already mined from original database and avoids start-from-scratch process. In addition, we deal with "weights-of-significance" which are automatically regulated as the incremental databases are evolved and implant themselves in the original database. We maintain "hopeful fuzzy grids" and "frequent fuzzy grids" and our algorithm changes the status of the grids which have been discovered earlier so that they reflect the pattern drift in the updated quantitative databases. Our heuristic approach avoids maintaining many "hopeful fuzzy grids" at the initial level. The algorithm is illustrated with one numerical example and demonstration of experimental results are also incorporated.
SELF-CORRECTING MULTIGRID SOLVER
Authors: LEWANDOWSKI JEROME L. V.
Published: September 2006

A new multigrid algorithm based on the method of self-correction for the solution of elliptic problems is described. The method exploits information contained in the residual to dynamically modify the source term (right-hand side) of the elliptic problem. It has shown that the self-correcting solver is more efficient at damping the short wavelength modes of the algebraic error than its standard equivalent. When used in conjunction with a multigrid method, the resulting solver displays an improved convergence rate with no additional computational work.
SINGULAR INTEGRAL EQUATION METHOD FOR MULTIPLE CURVED EDGE CRACKS EMANATING FROM BOUNDARY OF HALF-PLANE
Authors: CHEN Y. Z. , LIN X. Y.
Published: September 2006

This paper provides, an elastic solution for multiple curved edge cracks emanating from the boundary of the half-plane. After placing the distributed dislocations at the prospective sites of cracks in an infinite plate, the principal part of the complex potentials is obtained. By using the concept of the modified complex potentials, the complementary part of the complex potentials can be derived. The whole complex potentials satisfy the traction free condition along the boundary of half-plane automatically. This is a particular advantage of the suggested method. This concept or method of the modified complex potentials is a counterpart of the Green's function method, which is universal in mathematical physics. The direct usage of this method cannot provide a solution in detail. Comparing with the line edge crack case, the following points are significant in the presented study. The relevant kernels in the integral equation are more complicated than in the line edge crack case and the relevant integrations in the problem should be completed on curves. This paper solves a rather complicated problem, the multiple curved edge crack problem, and gives the final solution. A singular integral equation is formulated with the dislocation distribution being unknown function and the traction being the right hand term. The singular integral equation is solved by using the curve length method in conjunction with the semiopening quadrature rule. Periodic curved edge crack problem is also addressed. Finally, several numerical examples are given to illustrate the efficiency of the method presented.
INTERVAL AND SUBINTERVAL ANALYSIS METHODS OF THE STRUCTURAL ANALYSIS AND THEIR ERROR ESTIMATIONS
Authors: ZHOU Y. T. , JIANG C. , HAN X.
Published: September 2006

In this paper, the interval analysis method is introduced to calculate the bounds of the structural displacement responses with small uncertain levels' parameters. This method is based on the first-order Taylor expansion and finite element method. The uncertain parameters are treated as the intervals, not necessary to know their probabilistic distributions. Through dividing the intervals of the uncertain parameters into several subintervals and applying the interval analysis to each subinterval combination, a subinterval analysis method is then suggested to deal with the structures with large uncertain levels' parameters. However, the second-order truncation error of the Taylor expansion and the linear approximation of the second derivatives with respect to the uncertain parameters, two error estimation methods are given to calculate the maximum errors of the interval analysis and subinterval analysis methods, respectively. A plane truss structure is investigated to demonstrate the efficiency of the presented method.
Atrial natriuretic factor negatively modulates secretin intracellular signaling in the exocrine pancreas
Authors: Sabbatini María E. , Vatta Marcelo S. , Davio Carlos A. , Bianciotti Liliana G.
Published: September 2006

We previously reported that atrial natriuretic factor (ANF) stimulates pancreatic secretion through NPR-C receptors coupled to PLC and potentiates secretin response without affecting cAMP levels. In the present study we sought to establish the intracellular signaling mechanism underlying the interaction between both peptides. In isolated pancreatic acini 100 nM ANF abolished cAMP accumulation evoked by any dose of secretin. Lower doses of ANF (1 fM, 1 pM, 1 and 10 nM) dose dependently reduced EC50secretin-evoked cAMP. Although ANF failed to affect cAMP stimulated by amthamine (selective H2 agonist) or isoproterenol (β-adrenergic agonist), it abolished VIP-induced cAMP formation. ANF inhibitory effect was prevented by U-73122 (PLC inhibitor) and GF-109203X (PKC inhibitor) but unaltered by PKG and nitric oxide synthase inhibition, supporting that the PLC/PKC pathway mediated the effect. ANF response was mimicked by cANP (4–23 amide) and abolished by pertussis toxin, strongly supporting NPR-C receptor activation. In vivo studies showed that ANF at 0.5 μg·kg−1·h−1enhanced secretion stimulated by 1 U·kg−1·h−1secretin but at 1 and 2 μg·kg−1·h−1it abolished secretin response. However, ANF at such doses failed to modify the secretion evoked by carbachol or CCK. Present results show that ANF negatively modulated secretin secretory response and intracellular signaling through the activation of NPR-C receptors coupled to the PLC/PKC pathway. Furthermore, the finding that ANF also inhibited VIP-evoked cAMP supports a selective modulation of class II G-protein coupled receptors by ANF. Present findings suggest that ANF may play a protective role by reducing secretin response to avoid overstimulation.
Effects of residential exercise training on heart rate recovery in coronary artery patients
Authors: Legramante Jacopo M. , Iellamo Ferdinando , Massaro Michele , Sacco Sergio , Galante Alberto
Published: September 2006

The aims of the present study are twofold: 1) to investigate whether heart rate recovery (HRR) after a cycle ergometry test is affected by exercise training and 2) to test the ability of HRR to replicate the baroreflex sensitivity (BRS) changes that occur in response to an exercise training program in coronary artery patients. We randomized 82 coronary artery patients undergoing a residential cardiac rehabilitation program to an exercise training group (TR; n = 43) and an untrained group (UTR; n = 39). All of the patients underwent an exercise test before and after the rehabilitation program. HRR was recorded at the end of the 1st and 2nd min after exercise. BRS was determined at rest before and after treatment. HRR after the 2nd min was significantly improved in TR patients (−21.4 ± 0.9 beats/min) compared with UTR patients (−17.8 ± 1.2 beats/min) at the end of the training program. Improvement in HRR paralleled that in BRS in TR patients (from 3.2 ± 0.3 to 5.3 ± 0.8 ms/mmHg; P < 0.001), whereas no significant change was evident in UTR patients (from 3.5 ± 0 to 4.0 ± 0.4 ms/mmHg; P = 0.230). Our data show that HRR in the 2nd min after the cessation of a cycle ergometer exercise test increased in coronary artery patients after an exercise training period. This result confirms the positive effect induced by exercise training on HRR and extends the conclusions of previous studies to different modalities of exercise (i.e., cycle ergometer). HRR might provide an additional simple marker of the effectiveness of physical training programs in cardiac patients.
ATP increases intracellular calcium in supraoptic neurons by activation of both P2X and P2Y purinergic receptors
Authors: Song Zhilin , Vijayaraghavan Sukumar , Sladek Celia D.
Published: September 2006

ATP increases intracellular calcium concentration ([Ca2+]i) in supraoptic nucleus (SON) neurons in hypothalamo-neurohypophyseal system explants loaded with the Ca2+-sensitive dye, fura 2-AM. Involvement of P2X purinergic receptors (P2XR) in this response was anticipated, because ATP stimulation of vasopressin release from hypothalamo-neurohypophyseal system explants required activation of P2XRs, and activation of P2XRs induced an increase in [Ca2+]iin dissociated SON neurons. However, the ATP-induced increase in [Ca2+]ipersisted after removal of Ca2+from the perifusate ([Ca2+]o). This suggested involvement of P2Y purinergic receptors (P2YR), because P2YRs induce Ca2+release from intracellular stores, whereas P2XRs are Ca2+-permeable ion channels. Depletion of [Ca2+]istores with thapsigargin (TG) prevented the ATP-induced increase in [Ca2+]iin zero, but not in 2 mM [Ca2+]o, indicating that both Ca2+influx and release of intracellular Ca2+contribute to the ATP response. Ca2+influx was partially blocked by cadmium, indicating a contribution of voltage-gated Ca2+channels. PPADS (pyridoxal-phosphate-6-azophenyl-2′,4′-disulphonic acid), and iso-PPADS, P2XR antagonists, attenuated, but did not abolish, the ATP-induced increase in [Ca2+]i. Combined treatment with PPADS or iso-PPADS and TG prevented the response. A cocktail of P2YR agonists consisting of UTP, UDP, and 2-methylthio-ADP increased [Ca2+]i(with or without tetrodotoxin) that was markedly attenuated by TG. 2-Methylthio-ADP alone induced consistent and larger increases in [Ca2+]ithan UTP or UDP. MRS2179, a specific P2Y1R antagonist, eliminated the response to ATP in zero [Ca2+]o. Thus, both P2XR and P2YR participate in the ATP-induced increase in [Ca2+]i, and the P2Y1R subtype is more prominent than P2Y2R, P2Y4R, or P2Y6R in SON.