bluuebunny/crossref_metadata_2025 huggingface dataset:
Boundary-layer development on the afterbody of an engine nacelle
Authors: Lai Eugene , Squire L. C.
Published: April 2006

Measurements have been made of the pressure distribution and turbulent-boundary-layer development on the afterbody of a model engine nacelle with a jet exhausting from the base and with the jet replaced by a parallel solid sting. It was found that the effect of replacing the jet by a solid body was to increase the pressure recovery over the afterbody and hence give a lower drag than with the jet. These changes in the pressure distribution affected the boundary-layer development and turbulence structure by different methods based on a momentum integral equation and the kinetic equation for the turbulence. Both methods approximately incorporate the effects of convergence and divergence of the flow caused by changes in transverse curvature of the surface. Neither method was completely satisfactory for the prediction of the overall boundary-layer development.

It was also found that, near the tail of the model, where the body radius is decreasing rapidly, the Reynolds shear stress was much lower than it would be in a two-dimensional boundary layer with the same pressure gradient. Calculations and analysis based on earlier work show that this reduction is directly related to the rates of strain associated with the convergence of the streamlines over the afterbody.
Shoaling gravity waves: comparisons between field observations, linear theory, and a nonlinear model
Authors: Elgar Steve , Guza R. T.
Published: April 2006

Observed statistics of non-breaking ocean-surface gravity waves shoaling between 4 and 1 m depths are compared with the predictions of linear finite-depth theory and a nonlinear model. The linear theory included effects of the directional distribution of energy within each frequency component. The nonlinear model, which does not consider directional effects, is based on Boussinesq-type equations for a sloping bottom (Freilich & Guza 1984). Given initial conditions in 4 m depth, the nonlinear model more accurately predicts the evolution of energy spectra, coherence and phase speed between sensors, and lengths of runs of high waves than does the linear theory. In four out of five cases, observed trends in the evolution of sea-surface-elevation skewness are predicted by the nonlinear model, while linear theory predicts zero skewness. Neither model can explain changes in the directional spectra observed between 9 and 4 m depths.
Wave-power absorption by an oscillating water column in a channel
Authors: Malmo O. , Reitan A.
Published: April 2006

Wave-power absorption by an oscillating water column in a channel is studied within linear theory, and for different boundary conditions regarding the regions between the absorber and the channel walls. Particular attention is given to the effect of placing projecting sidewalls in front of the column.
Creeping motion of a sphere through a Bingham plastic
Authors: Beris A. N. , Tsamopoulos J. A. , Armstrong R. C. , Brown R. A.
Published: April 2006

A solid sphere falling through a Bingham plastic moves in a small envelope of fluid with shape that depends on the yield stress. A finite-element/Newton method is presented for solving the free-boundary problem composed of the velocity and pressure fields and the yield surfaces for creeping flow. Besides the outer surface, solid occurs as caps at the front and back of the sphere because of the stagnation points in the flow. The accuracy of solutions is ascertained by mesh refinement and by calculation of the integrals corresponding to the maximum and minimum variational principles for the problem. Large differences from the Newtonian values in the flow pattern around the sphere and in the drag coefficient are predicted, depending on the dimensionless value of the critical yield stressYgbelow which the material acts as a solid. The computed flow fields differ appreciably from Stokes’ solution. The sphere will fall only whenYgis below 0.143 For yield stresses near this value, a plastic boundary layer forms next to the sphere. Boundary-layer scalings give the correct forms of the dependence of the drag coefficient and mass-transfer coefficient on yield stress for values near the critical one. The Stokes limit of zero yield stress is singular in the sense that for any small value ofYgthere is a region of the flow away from the sphere where the plastic portion of the viscosity is at least as important as the Newtonian part. Calculations For the approach of the flow field to the Stokes result are in good agreement with the scalings derived from the matched asymptotic expansion valid in this limit.
Numerical simulation of the turbulent Rayleigh–Bénard problem using subgrid modelling
Authors: Eidson Thomas M.
Published: April 2006

A numerical simulation of turbulent natural convection (the Rayleigh–Bénard problem) has been conducted using large-eddy-simulation (LES) methods and the results compared with several experiments. The development of the LES equation is outlined and discussed. The modelling of the small-scale turbulent motion (called subgrid modelling) is also discussed. The resulting LES equations are solved and data collected over a short period of time in a similar manner to the direct simulation of the governing conservation equations. An explicit, second-order accurate, finite-difference scheme is used to solve the equations. Various average properties of the resulting flow field are calculated from the data and compared with experimental data in the literature. The use of a subgrid model allows a higher value of Ra to be simulated than was previously possible with a direct simulation. The highest Ra successfully simulated was 2.5 × 106. The problems at higher values of Ra are discussed and suggestions for improvements made.
Waves due to a steadily moving source on a floating ice plate
Authors: Davys J. W. , Hosking R. J. , Sneyd A. D.
Published: April 2006

The propagation of flexural waves in floating ice plates is governed by two restoring forces – elastic bending of the plate, and the tendency of gravity to make the upper surface of the supporting water horizontal. This paper studies steady wave patterns generated by a steadily moving source on a water–ice system that is assumed to be homogeneous and of infinite horizontal extent, using asymptotic Fourier analysis to give a simple description of the wave pattern far from the source. Short-wavelength elastic waves propagate ahead, while the long gravity waves appear behind; and, depending on the system parameters, one, two or no caustics may appear. Wavecrest patterns are shown, and the amplitude variation with direction from the source is given. Where the two caustics just merge together, a special mathematical function analogous to the Airy function is introduced to describe wave amplitudes. These waves can be detected by a strainmeter embedded in the ice, and we compare its theoretical response with some experimental measurements.
Chaotic mode competition in parametrically forced surface waves
Authors: Ciliberto S. , Gollub J. P.
Published: April 2006

Vertical forcing of a fluid layer leads to standing waves by means of a subharmonic instability. When the driving amplitude and frequency are chosen to be near the intersection of the stability boundaries of two nearly degenerate modes, we find that they can compete with each other to produce either periodic or chaotic motion on a slow timescale. We utilize digital image-processing methods to determine the time-dependent amplitudes of the competing modes, and local-sampling techniques to study the onset of chaos in some detail. Reconstruction of the attractors in phase space shows that in the chaotic regime the dimension of the attractor is fractional and at least one Lyapunov exponent is positive. The evidence suggests that a theory incorporating four coupled slow variables will be sufficient to account for the mode competition.
The turbulent mixing layer: geometry of large vortices
Authors: Browand F. K. , Troutt T. R.
Published: April 2006

Several means for visualizing large-scale vortex structure in a turbulent mixing layer are proposed. Most of the observations are recorded along the low-speed side of the mixing layer, external to the rotational portion of the flow. Conventional correlation measurements in both the streamwise and spanwise directions indicate that the vortex structure becomes independent of the downstream coordinate in a non-dimensional distance of order λx/θi = 300–400, where $\lambda = \Delta U/2\overline{U}$ is the speed ratio and θi is the initial integral thickness. Simultaneous hot-wire measurements at 12 spanwise positions allow computer reconstruction of the velocity field as a function of span and time. These visualizations show the vortex structures to be primarily aligned across the span of the flow, but to contain irregularities. Spanwise correlation lengths are of the order of 3–5δω (δω is the local vorticity thickness). However, the large vortices typically have lengths of order 20δω when the irregularities along the span are ignored.
Creeping plumes
Authors: Olson Peter , Singer Harvey
Published: April 2006

Results of laboratory experiments are used to determine the morphology and the ascent rate of growing buoyant plumes in a homogeneous, viscous fluid. The plumes were formed by injecting a glucose solution through a small orifice into another glucose solution of different density. Two classes of creeping (low-Reynolds-number) plumes are investigated: (i) diapiric plumes, for which the plume viscosity is approximately equal to the ambient-fluid viscosity, and (ii) cavity plumes, for which the plume fluid is much less viscous than the ambient fluid. Fully developed diapirs consist of a tapered cylindrical stem capped by a mushroom-shaped vortex at its leading edge. Fully developed cavity plumes consist of a nearly spherical chamber connected to the source by a narrow umbilical conduit. It is observed that the ascent velocity of cavity plumes increases with time as t⅖. The ascent velocity of diapirs is found to be proportional to the terminal velocity of a cylinder moving parallel to its axis. The presence of pre-existing conduits alters the morphology of cavity plumes and greatly increases their ascent rate. Fossil conduits act as plume guides by offering low-resistance ascent paths. Finally, a series of experiments have been made on the interaction between cavity plumes and a large-scale background circulation. A low-viscosity plume generated by a source towed steadily through a highly viscous fluid breaks into a chain of regularly spaced, individual cavities, as first demonstrated by Skilbeck & Whitehead. The cavities ascend as an inclined linear array of Stokes droplets. Dimensional analysis is used to derive scaling laws for the cavity volumes and their replication rate in terms of the source parameters and the tow speed. The qualitative results from these experiments generally lend support to the hypothesis that buoyant plumes in the Earth's mantle are the source of hot-spot volcanism. In particular the experiments suggest an explanation for the observation that hot spots remain nearly fixed in the presence of mantle convection.
Space–time results for a separating turbulent boundary layer using a rapidly scanning laser anemometer
Authors: Chehroudi B. , Simpson R. L.
Published: April 2006

A rapidly scanning one-velocity-component directionally sensitive fringe-type laser-Doppler anemometer which scans the measurement volume perpendicular to the optical axis of the transmitting optics was used to investigate the flow structure of the steady freestream separated turbulent boundary layer of Simpson, Chew & Shivaprasad (1981a). Space–time correlations were obtained for the first time in a separated turbulent boundary layer and showed that the integral lengthscale Ly for the large eddies grows in size towards detachment, although the ratio of this lengthscale to the boundary-layer thickness remains constant. Results also indicate local dependence of the backflow on the middle and outer regions of the boundary layer at a given instant in time.
Stability of finite-amplitude interfacial waves. Part 1. Modulational instability for small-amplitude waves
Authors: Grimshaw R. H. J. , Pullin D. I.
Published: April 2006

In two previous papers (Pullin & Grimshaw 1983a, b) we studied the wave profile and other properties of finite-amplitude interfacial progressive waves in a two-layer fluid. In this and the following paper (Pullin & Grimshaw 1985) we discuss the stability of these waves to small perturbations. In this paper we obtain anatytical results for the long-wavelength modulational instability of small-amplitude waves. Using a multiscale expansion, we obtain a nonlinear Schrödinger equation coupled to a wave-induced mean-flow equation to describe slowly modulated waves. From these coupled equations we determine the stability of a plane progressive wave. Our results are expressed by determining the instability bands in the (p, q)-plane, where (p, q) is the modulation wavenumber, and are obtained for a range of values of basic density ratio and undisturbed layer depths.
Flow along a channel with a time-dependent indentation in one wall: the generation of vorticity waves
Authors: Pedley T. J. , Stephanoff K. D.
Published: April 2006

We describe flow-visualization experiments and theory on the two-dimensional unsteady flow of an incompressible fluid in a channel with a time-dependent indentation in one wall. There is steady Poiseuille flow far upstream, and the indentation moves in and out sinusoidally, its retracted position being flush with the wall. The governing parameters are Reynolds number Re, Strouhal number (frequency parameter) St and amplitude parameter ε (the maximum fraction of the channel width occupied by the indentation); most of the experiments were performed with ε ≈ 0.4. For St ≤ 0.005 the flow is quasi-steady throughout the observed range of Re (360 < Re < 1260). For St > 0.005 a propagating train of waves appears, during every cycle, in the core flow downstream of the indentation, and closed eddies form in the separated flow regions on the walls beneath their crests and above their troughs. Later in the cycle, a second, corotating eddy develops upstream of the first in the same separated-flow region (‘eddy doubling’), and, later still, three-dimensional disturbances appear, before being swept away downstream to leave undisturbed parallel flow at the end of the cycle. The longitudinal positions of the wave crests and troughs and of the vortex cores are measured as functions of time for many values of the parameters; they vary with St but not with Re. Our inviscid, long-wavelength, small-amplitude theory predicts the formation of a wavetrain during each cycle, in which the displacement of a core-flow streamline satisfies the linearized Kortewegde Vries equation downstream of the indentation. The waves owe their existence to the non-zero vorticity gradient in the oncoming flow. Eddy formation and doubling are not described by the theory. The predicted positions of the wave crests and troughs agree well with experiment for the larger values of St used (up to 0.077), but less well for small values. Analysis of the viscous boundary layers indicates that the inviscid theory is self-consistent for sufficiently small time, the time of validity increasing as St increases (for fixed ε).
Notfallsonographie am Thorax – a pictorial essay
Authors: Mathis
Published: April 2006

Durch die Einführung tragbarer Ultraschallsysteme ist Einsatz der Sonographie praktisch überall möglich. In diesem pictorial essay werden ausgehend von den Ursachen und Symptomen wie stumpfes Thoraxtrauma, Thoraxschmerz und Dyspnoe die verschiedenen Krankheitsbilder dargestellt, die sonographisch diagnostiziert werden können und deren sonomorphologische Charakteristika beschrieben.
A global magnetic model of Saturn's magnetosphere and a comparison with Cassini SOI data
Authors: Alexeev I. I. , Kalegaev V. V. , Belenkaya E. S. , Bobrovnikov S. Y. , Bunce E. J. , Cowley S. W. H. , Nichols J. D.
Published: April 2006

A re‐scaling of a recent model of Jupiter's magnetosphere incorporating ring current, magnetopause, and tail current systems is used as a starting‐point for modeling Saturn's magnetospheric field. The model is compared with observations obtained by Cassini during its Saturn orbit insertion fly‐through of Saturn's magnetosphere, and is shown to give a good description. Comparison of ring current parameters obtained on the inbound and early outbound passes, when the magnetosphere was expanded due to low solar wind pressure, with those obtained by Voyager‐1 under more usual conditions, and by Pioneer‐11 when the magnetosphere was compressed, suggests that the ring current magnetic moment increases with system size. The effect is proposed to be due to radial stress balance conditions in a rapidly rotating magnetosphere, and has consequences for the dependence of magnetosphere size on solar wind pressure.
Synchronization in networks with random interactions: Theory and applications
Authors: Feng Jianfeng , Jirsa Viktor K. , Ding Mingzhou
Published: April 2006

Synchronization is an emergent property in networks of interacting dynamical elements. Here we review some recent results on synchronization in randomly coupled networks. Asymptotical behavior of random matrices is summarized and its impact on the synchronization of network dynamics is presented. Robert May’s results on the stability of equilibrium points in linear dynamics are first extended to systems with time delayed coupling and then nonlinear systems where the synchronized dynamics can be periodic or chaotic. Finally, applications of our results to neuroscience, in particular, networks of Hodgkin-Huxley neurons, are included.
Functional holography analysis: Simplifying the complexity of dynamical networks
Authors: Baruchi Itay , Grossman Danny , Volman Vladislav , Shein Mark , Hunter John , Towle Vernon L. , Ben-Jacob Eshel
Published: April 2006

We present a novel functional holography (FH) analysis devised to study the dynamics of task-performing dynamical networks. The latter term refers to networks composed of dynamical systems or elements, like gene networks or neural networks. The new approach is based on the realization that task-performing networks follow some underlying principles that are reflected in their activity. Therefore, the analysis is designed to decipher the existence of simple causal motives that are expected to be embedded in the observed complex activity of the networks under study. First we evaluate the matrix of similarities (correlations) between the activities of the network’s components. We then perform collective normalization of the similarities (or affinity transformation) to construct a matrix of functional correlations. Using dimension reduction algorithms on the affinity matrix, the matrix is projected onto a principal three-dimensional space of the leading eigenvectors computed by the algorithm. To retrieve back information that is lost in the dimension reduction, we connect the nodes by colored lines that represent the level of the similarities to construct a holographic network in the principal space. Next we calculate the activity propagation in the network (temporal ordering) using different methods like temporal center of mass and cross correlations. The causal information is superimposed on the holographic network by coloring the nodes locations according to the temporal ordering of their activities. First, we illustrate the analysis for simple, artificially constructed examples. Then we demonstrate that by applying the FH analysis to modeled and real neural networks as well as recorded brain activity, hidden causal manifolds with simple yet characteristic geometrical and topological features are deciphered in the complex activity. The term “functional holography” is used to indicate that the goal of the analysis is to extract the maximum amount of functional information about the dynamical network as a whole unit.
Measurements and simulations of the ablation stage of wire arrays with different initial wire sizes
Authors: Sinars D. B. , Cuneo M. E. , Yu E. P. , Lebedev S. V. , Cochrane K. R. , Jones B. , MacFarlane J. J. , Mehlhorn T. A. , Porter J. L. , Wenger D. F.
Published: April 2006

Comparisons of 20mm diameter, 300-wire tungsten arrays with different initial wire sizes were made on the 20MA Sandia Z facility. Radiographic measurements of each wire array, taken at the same point in the current during the wire ablation stage, show systematic differences. A detailed comparison of the radiography and self-emission data with simulations and analytic models suggests that a variation in the mass ablation rate with wire size may be responsible.
Losses at magnetic nulls in pulsed-power transmission line systems
Authors: Mendel C. W. , Pointon T. D. , Savage M. E. , Seidel D. B. , Magne I. , Vézinet R.
Published: April 2006

Pulsed-power systems operating in the terawatt regime must deal with large electron flows in vacuum transmission lines. In most parts of these transmission lines the electrons are constrained by the self-magnetic field to flow parallel to the conductors. In very low impedance systems, such as those used to drive Z-pinch radiation sources, the currents from multiple transmission lines are added together. This addition necessarily involves magnetic nulls that connect the positive and negative electrodes. The resultant local loss of magnetic insulation results in electron losses at the anode in the vicinity of the nulls. The lost current due to the magnetic null might or might not be appreciable. In some cases the lost current due to the null is not large, but is spatially localized, and may create a gas and plasma release from the anode that can lead to an excessive loss, and possibly to catastrophic damage to the hardware. In this paper we describe an analytic model that uses one geometric parameter (aside from straightforward hardware size measurements) that determines the loss to the anode, and the extent of the loss region when the driving source and load are known. The parameter can be calculated in terms of the magnetic field in the region of the null calculated when no electron flow is present. The model is compared to some experimental data, and to simulations of several different hardware geometries, including some cases with multiple nulls, and unbalanced feeds.
Compact design of a low temperature XY stage scanning tunneling microscope
Authors: Dubois C. , Bisson P. E. , Manuel A. A. , Fischer Ø. , Reymond S.
Published: April 2006

We describe the design and development of a compact low temperature XY stage scanning tunneling microscope dedicated to operation at low temperatures, in high magnetic fields, and in an ultrahigh vacuum environment. The system features a homemade compact scanning tunneling microscope (STM) head coupled to an inertially driven horizontal slider which allows a two-dimensional coarse positioning of the tip over 6×3mm2 with submicronic resolution. We also describe the geometry used to avoid coupling between the three-dimensional coarse and fine movements. To demonstrate the mechanical stability of the STM we display atomic resolution and large scale imaging. We illustrate the capabilities of our system by performing scanning tunneling spectroscopy on PbMo6S8 microcrystals.
ac driving amplitude dependent systematic error in scanning Kelvin probe microscope measurements: Detection and correction
Authors: Wu Yan , Shannon Mark A.
Published: April 2006

The dependence of the contact potential difference (CPD) reading on the ac driving amplitude in scanning Kelvin probe microscope (SKPM) hinders researchers from quantifying true material properties. We show theoretically and demonstrate experimentally that an ac driving amplitude dependence in the SKPM measurement can come from a systematic error, and it is common for all tip sample systems as long as there is a nonzero tracking error in the feedback control loop of the instrument. We further propose a methodology to detect and to correct the ac driving amplitude dependent systematic error in SKPM measurements. The true contact potential difference can be found by applying a linear regression to the measured CPD versus one over ac driving amplitude data. Two scenarios are studied: (a) when the surface being scanned by SKPM is not semiconducting and there is an ac driving amplitude dependent systematic error; (b) when a semiconductor surface is probed and asymmetric band bending occurs when the systematic error is present. Experiments are conducted using a commercial SKPM and CPD measurement results of two systems: platinum-iridium∕gap∕gold and platinum-iridium∕gap∕thermal oxide∕silicon are discussed.
Diffusion, activation, and regrowth behavior of high dose P implants in Ge
Authors: Satta A. , Simoen E. , Duffy R. , Janssens T. , Clarysse T. , Benedetti A. , Meuris M. , Vandervorst W.
Published: April 2006

Time evolution of the chemical profile, electrical activity, and regrowth of P implanted in Ge at a concentration above the maximum equilibrium solubility is investigated at 500°C rapid thermal annealing temperature. During the first anneal, a second, epitaxial regrowth of a part of the amorphous layer leads to P trapping in substitutional sites at a level of about 4×1020atoms∕cm3. However, nonsubstitutional P atoms frozen in the crystal at high concentration during recrystallization form large, inactive precipitates of peculiar circular shape. Simultaneously, long annealing time leads to continuing, extensive P out- and indiffusion affecting both the P chemical profile and junction sheet resistance.
A note on regularity conditions on ideal magnetohydrodynamic equations
Authors: Ohkitani K.
Published: April 2006

A regularity criterion for ideal magnetohydrodynamical equations is known to be given in terms of the vorticity and the current density fields [Caflisch et al., Commun. Math. Phys. 184, 443 (1997)]. A simple argument which utilizes Weber transform associated with cross helicity invariant shows that if the magnetic field is smooth, then so is the velocity field, thereby suggesting some room for improving the above criterion.
Electric field-induced structural changes in pentacene-based organic thin-film transistors studied by in situ micro-Raman spectroscopy
Authors: Cheng H. L. , Chou W. Y. , Kuo C. W. , Tang F. C. , Wang Y. W.
Published: April 2006

We have investigated the electric field-induced microscopic structural changes in polycrystalline pentacene-based organic transistors by using in situ micro-Raman spectroscopy. Extra vibrational modes resulting from molecular coupling effect in pentacene film were studied. The herringbone packing of pentacene molecules in solid film is affected by external field and the process is proven to be partially irreversible. In the meantime, in-phase coupling of the C-H bending mode was found to be highly related to the carrier transport of pentacene film. Obtained results suggest that optimal intermolecular π-orbital overlap of pentacene molecules is still a critical factor impacting the carrier transportation for pentacene film featuring polycrystalline morphology.
Near-infrared semiconductor subwavelength-wire lasers
Authors: Chin A. H. , Vaddiraju S. , Maslov A. V. , Ning C. Z. , Sunkara M. K. , Meyyappan M.
Published: April 2006

We report near-infrared lasing in the telecommunications band in gallium antimonide semiconductor subwavelength wires. Our results open the possibility of the use of semiconductor subwavelength-wire lasers in future photonic integrated circuits for telecommunications applications.
Electrochemically deposited zinc oxide arrays for field emission
Authors: Xu C. X. , Sun X. W. , Fang S. N. , Yang X. H. , Yu M. B. , Zhu G. P. , Cui Y. P.
Published: April 2006

Periodic zinc oxide rod arrays were fabricated on patterned templates by electrochemical deposition and were employed as field emitters. The morphology and crystal structure of the zinc oxide array were examined by scanning electron microscopy and x-ray diffraction, respectively. The dependence of the field emission current density J and the applied electric field E presented a two-stage slope behavior in ln(J∕E2)−1∕E plot according to Fowler-Nordheim equation. The mechanism of the electron emission is attributed to the defects in the electrochemically deposited zinc oxide rods.
Effect of environmental factors on the growth of grazed pasture in south-western Victoria
Authors: Birrell H. A. , Thompson R. L.
Published: April 2006

This paper presents work from several studies on pasture production that were conducted in south-west Victoria at the Pastoral Research Institute, Hamilton. The frequency with which pasture growth commenced for each week of autumn in the years from 1965 to 1991 was assessed. The median period for the commencement of growth was in the third week of March (although the average date was March 27). Autumn data from several trials conducted over 3 decades were collated and analysed. A relationship between the grazed pasture yield (average of stocking rates plots) at the end of autumn and the rainfall showed that 200 mm of rainfall in the 3 months to the end of May was optimal while higher rainfall depressed the growth. The average daily growth rates of introduced pasture (perennial rye grass, Lolium perenne L. cv. Victorian, phalaris, Phalaris aquatica L. cv. Australian, subterranean clover Trifolium subterranneum L. and volunteer species) were measured in 2- and 4-week growth periods (G 2 and G 4, kg DM/ha.day) for the seasonal growth cycles over 4 years (1980–84 except 1983) when grazed by Merino wether sheep at stocking rates of 10, 13 or 18 sheep/ha. The rainfall throughout the study was lower than normal. Although differences in the animal performance between the stocking rates were only small, at the low stocking rate capeweed (Arctotheca calendula L.) in patches became the major component of the sward. Greater variation in G 2 than in G 4 indicated that growth responded quickly to current environmental conditions. A nonlinear regression accounted for 74% of the variance in G 2 when related to the 3 climatic factors of daylength, soil temperature at 10 cm depth and the soil moisture to a depth of 10 cm, and a plant factor of green herbage yield. The 26 % of unaccounted variance appears to be associated with an effect of stocking rate, possibly botanical composition. The botanical composition was not continuously monitored hence the only sward character included in the investigation was herbage yield. Comparison of the patterns of pasture growth from different latitudes indicated that while the growth pattern in south-western Victoria is erratic, it is intermediary between Mediterranean and temperate pasture types. Understanding this aspect has implications for improving the efficiency of animal production in this environment.
Nitrogen use efficiency from urea applied to a tall wheatgrass (Elytrigia elongata) prairie in a sodic soil
Authors: Barbieri P. A. , Echeverría H. E. , Rozas H. R. Sainz , Picone L. I.
Published: April 2006

Studies of nitrogen (N) transformations under pastures are necessary to improve N agronomic efficiency (AE). A 2-year field experiment was conducted at Balcarce (37°45′S, 58°18′W), Argentina, on a pasture of tall wheatgrass (Elytrigia elongata) on a Typic Natracuol. The objective was to determine the effect of urea applied at varying rates (0, 90 and 180 kg N/ha) in autumn (late March) on soil mineral N, NH3 volatilisation losses (VL), herbage dry matter (DM) and plant accumulated N (Nplant) 46 days after fertilisation. In 1999, the accumulated VL were 3, 14 and 63 kg N/ha for 0, 90 and 180 kg applied N/ha, respectively, whereas in 2001, the accumulated VL were 1, 12 and 19 kg N/ha, respectively. Plant accumulated N was 32, 75 and 108 kg/ha in 1999, whereas in 2001, Nplant was 12, 34 and 58 kg/ha for 0, 90 and 180 kg N/ha, respectively. In both years, N AE ranged from 10 to 15 kg DM/kg applied N and the N recovered fraction (RF) ranged from 46 to 25% of applied N in 1999 and 2001, respectively. In 1999, unaccounted N (Nunac.) ranged from 41 to 23%, whereas in 2001, Nunac. ranged from 67 to 69% of applied N. Results of this study indicate that VL and denitrification affected the RF, and, for weather conditions of this area, VL would be the main N loss mechanism. These results indicate that management strategies to improve N use efficiency could be the utilisation of split N rates and N sources without urea.
Birdsfoot trefoil (Lotus corniculatus) and greater lotus (Lotus uliginosus) in perennial pastures in eastern Australia. 2. Adaptation and applications of lotus-based pasture
Authors: Ayres J. F. , Blumenthal M. J. , Lane L. A. , O'Connor J. W.
Published: April 2006

This co-learning study with greater lotus (Lotus uliginosus Schukr.) and birdsfoot trefoil (Lotus corniculatus L.) was undertaken in the Perennial Pasture Zone of New South Wales (NSW), Australia, in conjunction with 14 community groups. The overall study combined a field experiment investigating grazing management practices with a co-learning study assessing the adaptation and potential applications of these 2 Lotus species. The present paper reports on the co-learning study. Seventeen sites were established on farms situated in the North Coast, Northern Tablelands, North West Slopes, South Coast and Southern Tablelands regions of NSW. Of the 17 co-learning sites, greater lotus or birdsfoot trefoil was established successfully and yielded useful findings at 9 of 10 sites in northern NSW and 3 of 7 sites in southern NSW. Establishment failure of greater lotus or birdsfoot trefoil at the 5 remaining sites was associated with severe drought conditions at, or shortly following, sowing. Results from across the 4 regions are collated to report on the adaptation of the 2 Lotus species to a diversity of climatic, edaphic and management applications. The study has confirmed that greater lotus is a valuable perennial legume for high rainfall coastal plains, coastal low-lands, coastal hill-country and niche tablelands environments where the average annual rainfall (AAR) exceeds 1000 mm. Significantly, the study shows that birdsfoot trefoil has important potential for low fertility acidic soils on tablelands and slopes where the AAR is 650–1000 mm, especially in northern NSW.
Specifying the farming styles in viticulture
Authors: Mesiti L. , Vanclay F.
Published: April 2006

Fourteen styles of viticulture are defined: Astute Business Grower; Experimentalist Grower; Industry-Endorsed Early Adopter; Professional Scientific Manager; Experienced Manager; Labour-Efficient Grower; Low-Input Sustainable Agriculture Grower; Traditional Grower; Ethnic Grower; Conventional Grower; Retiree Grower; Hobby Grower; Sea-Change Grower; and Marginal Grower. The methodology to identify these farming styles included 6 focus groups in Mildura, Victoria, a face-to-face interview with 142 grape-growers in the Sunraysia region of Victoria, and qualitative interviewing with industry personnel and extension staff. Problems of social desirability response bias, the lack of self-identification by growers with styles, and literacy and other methodological issues meant that qualitative, participatory (emic) methods for identifying styles were not reliable. Following considerable immersion in the field, the researchers identified, on the basis of expert judgment (etic classification), the 14 farming styles in viticulture which they regard as a typology of ideal types. Benefits of the identification of farming styles in viticulture in terms of extension are discussed.
Differential induction of BLT receptor expression on human endothelial cells by lipopolysacharide, cytokines, and leukotriene B4
Authors: Qiu Hong , Johansson Anne-Sofie , Sjöström Mattias , Wan Min , Schröder Oliver , Palmblad Jan , Haeggström Jesper Z.
Published: April 2006

Leukotriene (LT) B4is a powerful chemotactic and immune modulating agent that signals via two receptors denoted BLT1and BLT2. Here we report that BLT1and BLT2are expressed at low levels in an apparently silent state in human umbilical vein endothelial cells (HUVEC). However, treatment with LPS leads to a >10 fold increase in the levels of BLT1mRNA without any significant effects on BLT2mRNA. In parallel, LPS also increases the amounts of BLT1protein. Tumor necrosis factor-α (TNF-α) increases the expression of BLT2mRNA ≈6 times above basal levels with only a modest increase in BLT1mRNA. Interleukin-1β causes variable and parallel increases of both BLT1and BLT2mRNA. The natural ligand LTB4also increases BLT1, but not BLT2, mRNA and protein expression. Along with the induction of BLT1and/or BLT2, HUVEC acquire the capacity to respond to LTB4with increased levels of intracellular calcium and these signals can be blocked by isotype selective BLT antagonists, CP-105696 and LY-255283. In addition, treatment of HUVEC with LTB4causes increased release of both nitrite, presumably reflecting nitric oxide (NO), and monocyte chemoattractant protein-1. Our data indicate that expression of functional BLT receptors may occur at the surface of endothelial cells in response to LPS, cytokines, and ligand, which in turn may have functional consequences during the early vascular responses to inflammation. Moreover, the results point to BLT receptors as potential targets for pharmacological intervention in LT-dependent inflammatory diseases such as asthma, rheumatoid arthritis, and arteriosclerosis.
Phosphoinositide-3 Kinase–Rac1–c-Jun NH2-terminal Kinase Signaling Mediates Collagen I–induced Cell Scattering and Up-Regulation of N-Cadherin Expression in Mouse Mammary Epithelial Cells
Authors: Shintani Yasushi , Wheelock Margaret J. , Johnson Keith R.
Published: April 2006

During epithelial-to-mesenchymal transitions (EMTs), cells must change their interactions with one another and with their extracellular matrix in a synchronized manner. To characterize signaling pathways cells use to coordinate these changes, we used NMuMG mammary epithelial cells. We showed that these cells become fibroblastic and scattered, with increased N-cadherin expression when cultured on collagen I. Rac1 and c-Jun NH2-terminal kinase (JNK) were activated when cells were plated on collagen I, and dominant inhibitory Rac1 (RacN17) or inhibition of JNK signaling prevented collagen I–induced morphological changes and N-cadherin up-regulation. Furthermore, inhibiting phosphoinositide-3 kinase (PI3K) activity prevented Rac1 and JNK activation as well as collagen I–induced N-cadherin up-regulation. These data implicate PI3K–Rac1–JNK signaling in collagen I–induced changes in NMuMG cells. To establish a role for N-cadherin in collagen I–induced cell scattering, we generated N-cadherin overexpressing and knockdown NMuMG cells and showed that knocking down N-cadherin expression prevented collagen I–induced morphological changes. Motility assays showed that cells overexpressing N-cadherin were significantly more motile than mock-transfected cells and that N-cadherin-mediated motility was collagen I dependent. In addition, we showed that cord formation and branching in three-dimensional culture (EMT-dependent events) required N-cadherin expression and PI3K–Rac1–JNK signaling.
A Distant Coilin Homologue Is Required for the Formation of Cajal Bodies inArabidopsis
Authors: Collier Sarah , Pendle Alison , Boudonck Kurt , van Rij Tjeerd , Dolan Liam , Shaw Peter
Published: April 2006

Cajal bodies (CBs) are subnuclear bodies that are widespread in eukaryotes, being found in mammals, many other vertebrates and in all plant species so far examined. They are mobile structures, moving, fusing, and budding within the nucleus. Here we describe a screen for Arabidopsis mutants with altered CBs and describe mutants that have smaller Cajal bodies (ncb-2, ncb-3), lack them altogether (ncb-1), have increased numbers of CBs (pcb) or have flattened CBs (ccb). We have identified the gene affected in the ncb mutants as a distant homolog of the vertebrate gene that encodes coilin (At1g13030) and have termed the resulting protein Atcoilin. A T-DNA insertional mutant in this gene (ncb-4) also lacks Cajal bodies. Overexpression of Atcoilin cDNA in ncb-1 restores Cajal bodies, which recruit U2B″ as in the wild type, but which are, however, much larger than in the wild type. Thus we have shown that At1g13030 is required for Cajal body formation in Arabidopsis, and we hypothesize that the level of its expression is correlated with Cajal body size. The Atcoilin gene is unaffected in pcb and ccb, suggesting that other genes can also affect CBs.
Evaluating Effects of Aromatherapy Massage on Sleep in Children with Autism: A Pilot Study
Authors: Williams Tim I.
Published: April 2006

Previous studies have found beneficial effects of aromatherapy massage for agitation in people with dementia, for pain relief and for poor sleep. Children with autism often have sleep difficulties, and it was thought that aromatherapy massage might enable more rapid sleep onset, less sleep disruption and longer sleep duration. Twelve children with autism and learning difficulties (2 girls and 10 boys aged between 12 years 2 months to 15 years 7 months) in a residential school participated in a within subjects repeated measures design: 3 nights when the children were given aromatherapy massage with lavender oil were compared with 14 nights when it was not given. The children were checked every 30 min throughout the night to determine the time taken for the children to settle to sleep, the number of awakenings and the sleep duration. One boy′s data were not analyzed owing to lengthy absence. Repeated measures analysis revealed no differences in any of the sleep measures between the nights when the children were given aromatherapy massage and nights when the children were not given aromatherapy massage. The results suggest that the use of aromatherapy massage with lavender oil has no beneficial effect on the sleep patterns of children with autism attending a residential school. It is possible that there are greater effects in the home environment or with longer‐term interventions.
Regulatory T Cells, a Potent Immunoregulatory Target for CAM Researchers: Modulating Allergic and Infectious Disease Pathology (II)
Authors: Vojdani Aristo , Erde Jonathan
Published: April 2006

Regulatory T (Treg) cells maintain dominant control of immune responses to foreign materials and microbes. Appropriate Treg cell suppression of immune responses is essential for the maintenance of efficacious defensive responses and the limitation of collateral tissue damage due to excess inflammation. Allergy and infection are well studied and frequent afflictions in which Treg cells play an essential role. As such, they provide excellent models to communicate the significance and relevance of Treg cells to complementary and alternative medicine (CAM).
Methylibium petroleiphilum gen. nov., sp. nov., a novel methyl tert-butyl ether-degrading methylotroph of the Betaproteobacteria
Authors: Nakatsu Cindy H. , Hristova Krassimira , Hanada Satoshi , Meng Xian-Ying , Hanson Jessica R. , Scow Kate M. , Kamagata Yoichi
Published: April 2006

A Gram-negative, rod-shaped, motile, non-pigmented, facultative aerobe that grew optimally at pH 6.5 and 30 °C (strain PM1T) was isolated for its ability to completely degrade the gasoline additive methyl tert-butyl ether. Analysis of the 16S rRNA gene sequence indicated that this bacterium was a member of the class Betaproteobacteria in the Sphaerotilus–Leptothrix group. The 16S rRNA gene sequence identity to other genera in this group, Leptothrix, Aquabacterium, Roseateles, Sphaerotilus, Ideonella and Rubrivivax, ranged from 93 to 96 %. The chemotaxonomic data including Q-8 as the major quinone, C16 : 1ω7c and C16 : 0 as the major fatty acids and a DNA G+C content of 69 mol%, support the inclusion of strain PM1T in the class Betaproteobacteria. It differed from other members of the Sphaerotilus–Leptothrix group by being a facultative methylotroph that used methanol as a sole carbon source, and by also being able to grow heterotrophically in defined media containing ethanol, toluene, benzene, ethylbenzene and dihydroxybenzoates as sole carbon sources. On the basis of the morphological, physiological, biochemical and genetic information, a new genus and species, Methylibium petroleiphilum gen. nov., sp. nov., is proposed, with PM1T (=ATCC BAA-1232T=LMG 22953T) as the type strain.
Rhodococcus kroppenstedtii sp. nov., a novel actinobacterium isolated from a cold desert of the Himalayas, India
Authors: Mayilraj S. , Krishnamurthi S. , Saha P. , Saini H. S.
Published: April 2006

The taxonomic position of an actinomycete, strain K07-23T, isolated from a cold desert of the Himalayas, India, was established by a polyphasic approach. The strain exhibited phenotypic characters that were typical of the genusRhodococcus. 16S rRNA gene sequence (1467 bases) comparisons confirmed that strain K07-23Tbelongs to the genusRhodococcus. 16S rRNA sequence similarity studies showed that the isolate is very closely related toNocardia corynebacterioidesDSM 20151T(98.6 %), which has been recently reclassified asRhodococcus corynebacterioides. It showed 94.4–96.6 % sequence similarity with other species of the genusRhodococcus. However, genomic relatedness between strain K07-23TandR. corynebacterioidesas revealed by DNA–DNA hybridization was low (62 %). Based on polyphasic analysis, strain K07-23Tcould be clearly distinguished from other species. It is proposed that strain K07-23T(=MTCC 6634T=DSM 44908T=JCM 13011T) represents a novel species ofRhodococcus,Rhodococcus kroppenstedtiisp. nov.
Porphyrobacter dokdonensis sp. nov., isolated from sea water
Authors: Yoon Jung-Hoon , Kang So-Jung , Lee Mi-Hwa , Oh Hyun Woo , Oh Tae-Kwang
Published: April 2006

A Gram-negative, non-motile, non-spore-forming, slightly halophilic bacterial strain, DSW-74T, was isolated from sea water off the island of Dokdo, Korea, and its taxonomic position was investigated by a polyphasic study. Strain DSW-74T grew optimally at 37 °C and in the presence of 2 % (w/v) NaCl. It contained Q-10 as the predominant ubiquinone and C17 : 1
ω6c and C18 : 1
ω7c as the major fatty acids. Its DNA G+C content was 65.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DSW-74T was most closely related to Porphyrobacter species. Similarity values between the 16S rRNA gene sequence of strain DSW-74T and those of the type strains of recognized Porphyrobacter species and of Erythromicrobium ramosum were in the range 97.4–98.7 %. Strain DSW-74T exhibited 16S rRNA gene sequence similarity values of <97.5 % to recognized Erythrobacter species and the other species used in the phylogenetic analysis. DNA–DNA relatedness levels and differential phenotypic properties made it possible to categorize strain DSW-74T as representing a novel Porphyrobacter species. On the basis of the taxonomic data presented, it is proposed that DSW-74T (=KCTC 12395T=DSM 17193T) should be classified in the genus Porphyrobacter as the type strain of a novel species, Porphyrobacter dokdonensis sp. nov.