bluuebunny/crossref_metadata_2025 huggingface dataset:
‘Sink’ effect in a shock-induced boundary layer on attenuation
Authors: Deckker B. E. L.
Published: April 2006

Experiments on shock-wave attenuation in a porous tube have shown that attenuation is a function of distance from the origin and the rate of cross-mass flow per unit area. It is a linear function of distance if the cross-mass flow rate per unit area is held constant. In a tube with solid walls the relationship between attenuation, mass extraction rate per unit area and distance is similar to that in a proous tube. The ratio of the local attenuation to the local cross-mass flow, or mass extraction rate, per unit area is the same linear function of distance in both sets of experiments. The mechanism of attenuation is therefore also identical.
An alternative approach to linear and nonlinear stability calculations at finite Reynolds numbers
Authors: Smith F. T. , Papageorgiou D. , Elliott J. W.
Published: April 2006

An extended version of the interactive boundary-layer approach which has been used widely in steady-flow calculations is applied here to the linear and nonlinear stability properties of channel flows and boundary layers in the moderate-to-large Reynolds-number regime. This is the regime of most practical concern. First, for linear stability the agreement found between the interactive approach and Orr-Sommerfeld results remains fairly close even at Reynolds numbers as low as about$\frac{1}{10}$of the critical value for plane Poiseuille flow, or$\frac{1}{5}$for Blasius flow. Secondly, nonlinear unsteady calculations and comparisons with full solutions obtained by enlarging the same method are also presented. Overall the work suggests that, at the finite Reynolds numbers where real interest lies, the dominant physical processes of instability in channel flow and boundary layers are of boundary-layer form, with interaction, and it suggests also an alternative numerical technique for determining those processes. This alternative technique uses the interactive boundary-layer method as the central means for obtaining full unsteady Navier-Stokes solutions.
Wake-induced galloping of two interfering circular cylinders
Authors: Bokaian A. , Geoola F.
Published: April 2006

Measurements are presented of fluid-dynamic instability of a smooth circular cylinder, free to oscillate laterally against linear springs in the wake from an identical stationary neighbouring body. The observations also encompassed determination of static forces on the downstream cylinder as functions of relative position of the cylinder pair. Most of the experiments were performed under two conditions of free-stream turbulence. Static tests indicated that both the drag coefficient and the Strouhal number of the downstream body are continuous functions of its relative position. The drag forces were found to be negative at small gaps. It was observed that the transverse extent of the force field increases with increasing streamwise gap.

In the dynamic experiments, depending on the cylinders’ separation and structural damping, the cylinder exhibited a vortex-resonance, or a galloping, or a combined vortex-resonance and galloping, or a separated vortex-resonance and galloping. Whilst the characteristics of wake-excited motion were found to be essentially unaffected by a limited change in free-stream turbulence intensity, the galloping amplitudes were observed to be sensitive to the cylinders’ aspect ratio. An increase in the stability parameter caused significant effects on the cylinder response in amplitude domain. Wake observations behind the oscillating body indicated that in vortex lock-in the frequency of vortex-shedding locked to vibration frequency, but during small-amplitude galloping motion the shedding frequency behaved as if the cylinder was stationary.
Numerical solution of free-boundary problems in fluid mechanics. Part 1. The finite-difference technique
Authors: Ryskin G. , Leal L. G.
Published: April 2006

We present here a brief description of a numerical technique suitable for solving axisymmetric (or two-dimensional) free-boundary problems of fluid mechanics. The technique is based on a finite-difference solution of the equations of motion on an orthogonal curvilinear coordinate system, which is also constructed numerically and always adjusted so as to fit the current boundary shape. The overall solution is achieved via a global iterative process, with the condition of balance between total normal stress and the capillary pressure at the free boundary being used to drive the boundary shape to its ultimate equilibrium position.
Longitudinal dispersion of matter due to the shear effect of steady and oscillatory currents
Authors: Yasuda Hidekazu
Published: April 2006

The longitudinal dispersion due to the shear effect of a current is examined theoretically in the idealized two-dimensional case. This study reveals the process whereby the dispersion reaches a stationary stage after the release of the dispersing substance as an instantaneous line source in steady and in oscillatory currents. In addition, the relation between the stationary dispersion coefficients in steady and oscillatory currents is given analytically. Analysis of the dispersion during the initial stage needs a clear definition of the vertical average of the variance. We can understand the problem of the negative dispersion coefficient, which is obtained by the usual vertical average, through introduction of a new vertical average.
Time-domain measurements in separated flows
Authors: Castro I. P.
Published: April 2006

This paper describes a sampling technique which is non-periodic, but also non-random, and which allows a pulsed wire anemometer to be used to obtain time-domain information in separated flows. Data free from aliasing can be obtained at frequencies considerably higher than that associated with the maximum possible (periodic) sampling rate achievable with a pulsed-wire probe. Autocorrelation and spectral data obtained in three quite distinct types of flow are presented, as a demonstration of the technique. Some of the data serve to emphasize the special character of separated flows. It is shown that in some circumstances it is possible to obtain spectral data that are adequate for estimating the turbulent-energy dissipation rate (provided that an inertial subrange exists). The measurement of all the terms necessary to examine the balance of turbulent energy in separated flows – or, at least, those terms which can be obtained by standard hot-wire anemometry in low-intensity flows – is therefore a distinct possibility.
Slow-zone model for longitudinal dispersion in two-dimensional shear flows
Authors: Chikwendu S. C. , Ojiakor G. U.
Published: April 2006

A two-zone model is proposed for the longitudinal dispersion of contaminants in two-dimensional turbulent flow in open channels – a fast zone in the upper region of the flow, and a slow zone nearer to the bottom. The usual one-dimensional dispersion approach (Elder 1959) is used in each zone, but with different flow speeds U1 and U2 and dispersion coefficients D1 and D2 in the fast and slow zones respectively. However, turbulent vertical mixing is allowed at the interface between the two zones, with a small vertical diffusivity ε. This leads to a pair of coupled, linear, one-dimensional dispersion equations, which are solved by Fourier transformation. The Fourier-inversion integrals are analysed using two different methods.

In the first method asymptotically valid expressions are found using the saddle-point method. The resulting cross-sectional average concentration consists of a leading Gaussian distribution followed by a trailing Gaussian distribution. The trailing Gaussian cloud disperses (longitudinally) faster than the leading one, and this gives the long tail observed in most dispersion experiments. Significantly the peak value of the average concentration is found to decay exponentially with time at a rate which is close to the rate observed by Sullivan (1971) in the early stage of the dispersion process. The solution is useful for fairly small times, and both the calculated value of D1 and the predicted bulk concentration distribution are in meaningful agreement with the experimental and simulation data of Sullivan (1971).

In the second method an exact solution is found in the form of a convolution integral for the case D1 = D2 = D0. Explicit expressions which are valid for small times and for large times from the release of contaminant are found. For small times this exact solution confirms the basic results obtained by the saddle-point method. For large times the exact solution gives a contaminant concentration which approaches a Gaussian distribution travelling with the bulk speed as predicted by the Taylor model. The overall longitudinal dispersion coefficient at large times, D(∞), consists of the diffusivity D0 plus a contribution D[ell ](∞) which depends entirely on the vertical mixing. D(∞) is in good agreement with Chatwin's (1971) interpretation of Fischer's (1966) experimental data.
Moving contact lines on a two-dimensional rough surface
Authors: Jansons Kalvis M.
Published: April 2006

The dynamic contact angle for a contact line moving over a solid surface with random sparse spots of roughness is determined theoretically in the limit of zero capillary number. The model exhibits many of the observed characteristics of moving contact lines on real rough surfaces, including contact-angle hysteresis and stick-slip. Several types of rough surface are considered, and a comparison is made between periodic and random rough surfaces.
Scattering of acoustic waves into Tollmien-Schlichting waves by small streamwise variations in surface geometry
Authors: Goldstein M. E.
Published: April 2006

By using the triple-deck scaling of Stewartson (1969) and Messiter (1970) we show that small but relatively sudden surface geometry variations that produce only very weak static pressure variations can nevertheless produce strong, i.e. 0(1), coupling between an externally imposed acoustic disturbance and a spatially growing Tollmien- Schlichting wave. The analysis provides a qualitative explanation of the Leehey & Shapiro (1979) boundary-layer receptivity measurements and is in good quantitative agreement with the Aizin & Polyakov (1979) experiment. It may also explain why small ‘trip wires’ can promote early transition.
On the steady laminar flow of an incompressible viscous fluid in a curved pipe of elliptical cross-section
Authors: Topakoglu H. C. , Ebadian M. A.
Published: April 2006

A literature survey (Berger, Talbot & Yao 1983) indicates that laminar viscous flow in curved pipes has been extensively investigated. Most of the existing analytical results deal with the case of circular cross-section. The important studies dealing with elliptical cross-sections are mainly due to Thomas & Walters (1965) and Srivastava (1980). The analysis of Thomas & Walters is based on Dean's (1927, 1928) approach in which the simplified forms of the momentum and continuity equations have been used. The analysis of Srivastava is essentially a seminumerical approach, in which no explicit expressions have been presented.

In this paper, using elliptic coordinates and following the unsimplified formulation of Topakoglu (1967), the flow in a curved pipe of elliptical cross-section is analysed. Two different geometries have been considered: (i) with the major axis of the ellipse placed in the direction of the radius of curvature; and (ii) with the minor axis of the ellipse placed in the direction of the radius of curvature. For both cases explicit expressions for the first term of the expansion of the secondary-flow stream function as a function of the ellipticity ratio of the elliptic section have been obtained. After selecting a typical numerical value for the ellipticity ratio, the secondary-flow streamlines are plotted. The results are compared with that of Thomas & Walters. The remaining terms of the expansion of the flow field are not included, but they will be analysed in a future paper.
Analytical prediction of the transition from Mach to regular reflection over cylindrical concave wedges
Authors: Ben-Dor G. , Takayama K.
Published: April 2006

Two formulas, based on analytical considerations, which are capable of predicting the wedge angle of transition from Mach to regular reflection over cylindrical concave wedges, are developed. They are derived using Hornung, Oertel & Sandeman's (1979) conclusion that a Mach reflection can exist only if the corner-generated signals can catch up with the incident shock wave. The good agreement between the present models and the experimental results confirm Hornung et al.'s (1979) concept. The predictions of these models are in better agreement with experimental results than the predictions of Itoh, Okazaki & Itaya's (1981) model. The present models are very simple to use and apply but, like Itoh et al.'s (1981) model, they also lack the ability to account for the dependence of the transition angle on the radius of curvature of the cylindrical wedge.
Singularities in solutions of the three-dimensional laminar-boundary-layer equations
Authors: Williams James C.
Published: April 2006

The three-dimensional steady laminar-boundary-layer equations have been cast in the appropriate form for semisimilar solutions, and it is shown that in this form they have the same structure as the semisimilar form of the two-dimensional unsteady laminar-boundary-layer equations. This similarity suggests that there may be a new type of singularity in solutions to the three-dimensional equations: a singularity that is the counterpart of the Stewartson singularity in certain solutions to the unsteady boundary-layer equations.

A family of simple three-dimensional laminar boundary-layer flows has been devised and numerical solutions for the development of these flows have been obtained in an effort to discover and investigate the new singularity. The numerical results do indeed indicate the existence of such a singularity. A study of the flow approaching the singularity indicates that the singularity is associated with the domain of influence of the flow for given initial (upstream) conditions as is prescribed by the Raetz influence principle.
Topographic waves and the evolution of coastal currents
Authors: Johnson E. R.
Published: April 2006

An initial-value problem is considered for the oceanographically relevant case of slow flow over obstacles of small height and horizontal scale of order the fluid depth or larger. Previous work on starting flow over obstacles whose contours are closed (Johnson 1984) is extended to flow forced by a source–sink pair to cross a step change in depth bounded by a vertical sidewall. Bottom contours thus end abruptly and the near-periodic solutions of the earlier work are no longer possible. The relevant timescale for the motion is again the topographic vortex-stretching time h/2Ωh0, where h is the fluid depth, Ω the background rotation rate and h0 the step height. This time is taken to be long compared with the inertial period but short compared with the advection time. It is shown that if shallow water lies to the right (looking away from the wall) a wavefront moves outwards exponentially fast leaving behind a flow equivalent to that obtained by replacing the step by a rigid wall. If shallow water lies to the left the wavefront approaches the wall, forming at the wall–step junction an unsteady, exponentially thinning, singular region that transports the whole flux. The relevance of these solutions to experiments and steady solutions for free-surface and two-layer flows in Davey, Gill, Johnson & Linden (1984, 1985) is discussed.
Stokes flow past compound multiphase drops: the case of completely engulfed drops/bubbles
Authors: Sadhal S. S. , Oguz H. N.
Published: April 2006

In this paper the translatory motion of a compound drop is examined in detail for low-Reynolds-number flow. The compound drop, consisting of a liquid drop or a gas bubble completely coated by another liquid, moves in a third immiscible fluid. An exact solution for the flow field is found in the limit of small capillary numbers by approximating the two interfaces to be spherical. The solution is found for the general case of eccentric configuration with motion of the inner sphere relative to the outer together with the motion of the system in the continuous phase. The results show that the viscous forces tend to move the inner-fluid sphere towards the front stagnation point of the compound drop. For equilibrium of the inner sphere with respect to the outer there must, therefore, be a body force towards the front. This can only be achieved with the necessary condition that there be a buoyant force on the inner sphere, opposite to that of the compound drop in the continuous phase. For a given set of fluids, two or four equilibrium configurations may be found. Of these only one or two, respectively, are stable. The others are unstable. For the special case of concentric configuration, the equilibrium is always metastable.
Al-Kindī's braid
Authors: WRIGHT O.
Published: April 2006

An attempt is made here to evaluate the various versions that have been put forward for the more complex abstract melodic structures outlined by the Arab philosopher and music theorist al-Kindī (d. c. 874); to propose new interpretations in the context of a re-examination of the source text; and to locate their origin and meaning less within the general mathematical orientation of theory than in the elaboration of a descriptive metaphor.
Between Arabs, Turks and Iranians: The town of Basra, 1600–1700
Authors: MATTHEE RUDI
Published: April 2006

Early modern Basra is often portrayed as the end of an Ottoman chain of command that grew successively weaker as it stretched from Istanbul to the Persian Gulf. This article complicates the picture of an imperial outpost over which the metropole was unable to impose effective control by discussing seventeenth-century Basra as the point of convergence of various regional and trans-regional spheres of influence and jurisdiction. Basra remained contested territory long after the city was supposedly incorporated into the Ottoman framework in 1546, and in its subsequent history we see multiple actors engaged in a fierce struggle over power and income. Local authorities, regional tribal forces, and outside elements—the Portuguese and the two imperial powers with claims on the region, the Ottomans and the Safavids—participated in this struggle through alliance building and mutual manipulation.
Impact of immigration and HIV infection on tuberculosis incidence in an area of low tuberculosis prevalence
Authors: BAUSSANO I. , BUGIANI M. , GREGORI D. , PASQUALINI C. , DEMICHELI V. , MERLETTI F.
Published: April 2006

The aim of this study is to assess the effects of immigration from countries with a high prevalence of tuberculosis (HPCs), of HIV/AIDS prevalence, and the ageing of the indigenous population, on tuberculosis distribution in a low-prevalence area (LPCs), the Piedmont Region of Italy. Tuberculosis incidence and HIV cases were identified by linking records from the surveillance systems. Overall, 640 tuberculosis cases were identified and crude annual incidence was found to be 17·3/100000. The incidence rate ratio for HIV infection as a risk factor for tuberculosis (11·4 and 51·9 among individuals from HPCs and LPCs respectively) was greater than that for immigration from HPCs (6·7 and 30·9 among HIV+ and HIV− individuals). Immigration accounted for a larger number of incident cases [population attributable risk % (PAR %): 31·8 and 52·8% among HIV+ and HIV− individuals] than did HIV infection (PAR %: 5·4 and 11·1% among individuals from HPCs and LPCs). Efforts should be made to identify and treat young immigrants from HPCs.
Epidemic cholera in urban Zambia: hand soap and dried fish as protective factors
Authors: DUBOIS A. E. , SINKALA M. , KALLURI P. , MAKASA-CHIKOYA M. , QUICK R. E.
Published: April 2006

Between 28 November 2003 and 23 February 2004, 4343 cases and 154 deaths from cholera (case-fatality rate 3·5%) were reported in Lusaka, Zambia. A case-control study was conducted in February 2004 to assess potential transmission routes and prevention strategies. Consumption of raw vegetables was significantly associated with cholera [adjusted odds ratio (aOR) 4·7, 95% confidence interval (CI) 1·7–13, P=0·003). Consumption of a local sardine-like fish was protective (aOR 0·3, 95% CI 0·1–0·7, P=0·008). Hand soap was present in 90% of control homes and 58% of case homes. Observed hand soap was a strongly protective factor (aOR 0·1, 95% CI 0·04–0·4, P=0·001). No water source or treatment practice was significantly associated with cholera. This study documents the importance of foodborne transmission of cholera, illustrates the protective role of hand washing in an epidemic setting, and identifies a novel possible protective factor, a local fish, which warrants further research.
Whistler mode auroral hiss emissions observed near Jupiter's moon Io
Authors: Xin L. , Gurnett D. A. , Kivelson M. G.
Published: April 2006

On 16 October 2001, the Galileo spacecraft made a close flyby of Jupiter's moon Io. During the flyby the plasma wave instrument detected an electric field emission with spectral characteristics very similar to a type of whistler‐mode noise called “auroral hiss” that is commonly observed in Earth's auroral region. This paper gives a detailed analysis of the “auroral hiss” observed near Io. The frequency‐time spectrum of the emission has a sharp high‐frequency cutoff near the electron cyclotron frequency and a V‐shaped low‐frequency cutoff. On a frequency‐time spectrogram these cutoffs give the emission a characteristic funnel shape that is very similar to the spectrum of terrestrial auroral hiss. Strong magnetic field perturbations occurred near the vertex of the funnel indicating the presence of a field‐aligned current. To explain the origin of the emission, a brief review is given of whistler‐mode wave propagation and the unipolar inductor model of Io's interaction with the magnetosphere of Jupiter. Assuming propagation near the whistler‐mode resonance cone, ray‐tracing analyses show that the radiation originates from a source very close to the surface of Io. The source is located in the same region where field‐aligned currents are believed to originate in the ionosphere of Io. Since terrestrial auroral hiss is known to be produced by beams of low‐energy auroral electrons, these observations suggest that the auroral hiss at Io is generated by an electron beam that is part of the field‐aligned current system induced by the interaction of Io with the rapidly rotating magnetosphere of Jupiter.
Synchronization in asymmetrically coupled networks with node balance
Authors: Belykh Igor , Belykh Vladimir , Hasler Martin
Published: April 2006

We study global stability of synchronization in asymmetrically connected networks of limit-cycle or chaotic oscillators. We extend the connection graph stability method to directed graphs with node balance, the property that all nodes in the network have equal input and output weight sums. We obtain the same upper bound for synchronization in asymmetrically connected networks as in the network with a symmetrized matrix, provided that the condition of node balance is satisfied. In terms of graphs, the symmetrization operation amounts to replacing each directed edge by an undirected edge of half the coupling strength. It should be stressed that without node balance this property in general does not hold.
Nonequilibrium inertial dynamics of colloidal systems
Authors: Marini Bettolo Marconi Umberto , Tarazona Pedro
Published: April 2006

We consider the properties of a one-dimensional fluid of Brownian inertial hard-core particles, whose microscopic dynamics is partially damped by a heat bath. Direct interactions among the particles are represented as binary, instantaneous elastic collisions. Collisions with the heat bath are accounted for by a Fokker-Planck collision operator, whereas direct collisions among the particles are treated by a well known method of kinetic theory, the revised Enskog theory. By means of a time multiple time-scale method we derive the evolution equation for the average density. Remarkably, for large values of the friction parameter and/or of the mass of the particles we obtain the same equation as the one derived within the dynamic density functional theory (DDF). In addition, at moderate values of the friction constant, the present method allows to study the inertial effects not accounted for by DDF method. Finally, a numerical test of these corrections is provided.
Atomistic simulation of solid-liquid coexistence for molecular systems: Application to triazole and benzene
Authors: Eike David M. , Maginn Edward J.
Published: April 2006

A method recently developed to rigorously determine solid-liquid equilibrium using a free-energy-based analysis has been extended to analyze multiatom molecular systems. This method is based on using a pseudosupercritical transformation path to reversibly transform between solid and liquid phases. Integration along this path yields the free energy difference at a single state point, which can then be used to determine the free energy difference as a function of temperature and therefore locate the coexistence temperature at a fixed pressure. The primary extension reported here is the introduction of an external potential field capable of inducing center of mass order along with secondary orientational order for molecules. The method is used to calculate the melting point of 1-H-1,2,4-triazole and benzene. Despite the fact that the triazole model gives accurate bulk densities for the liquid and crystal phases, it is found to do a poor job of reproducing the experimental crystal structure and heat of fusion. Consequently, it yields a melting point that is 100K lower than the experimental value. On the other hand, the benzene model has been parametrized extensively to match a wide range of properties and yields a melting point that is only 20K lower than the experimental value. Previous work in which a simple “direct heating” method was used actually found that the melting point of the benzene model was 50K higher than the experimental value. This demonstrates the importance of using proper free energy methods to compute phase behavior. It also shows that the melting point is a very sensitive measure of force field quality that should be considered in parametrization efforts. The method described here provides a relatively simple approach for computing melting points of molecular systems.
Band offsets of Er2O3 films epitaxially grown on Si substrates
Authors: Zhu Y. Y. , Chen S. , Xu R. , Fang Z. B. , Zhao J. F. , Fan Y. L. , Yang X. J. , Jiang Z. M.
Published: April 2006

The experimental data on band alignments of high-k Er2O3 films epitaxially grown on Si substrates by molecular beam epitaxy are reported. By using x-ray photoelectron spectroscopy, the valence and the conduction-band offsets of Er2O3 to Si are obtained to be 3.1±0.1 and 3.5±0.3eV, respectively, showing a roughly symmetrical offset at the conduction and the valence band. The energy gap of Er2O3 is determined to be 7.6±0.3eV. From the band offset viewpoint, those obtained numbers indicate that Er2O3 could be a promising candidate for high-k gate dielectrics.
Strengthening and softening of nanocrystalline nickel during multistep nanoindentation
Authors: Pan D. , Nieh T. G. , Chen M. W.
Published: April 2006

Multistep load-unload nanoindentation was employed to address the effect of deformation-induced microstructural evolution on mechanical behavior of nanocrystalline Ni. Deformation discontinuity was deliberately introduced by unloading-reloading during nanoindentation testing, which allows us to examine the influence of microstructural evolution on the successive deformation. Strain strengthening/softening of nanocrystalline nickel, associated with the transition of deformation behavior from dislocation activity at high loading rates to a grain-boundary-mediated process at low loading rates, was uncovered by means of this experimental methodology.
Yield and economic benefits of common bean (Phaseolus vulgaris) and soybean (Glycine max) inoculation in northern Tanzania
Authors: Ndakidemi P. A. , Dakora F. D. , Nkonya E. M. , Ringo D. , Mansoor H.
Published: April 2006

On-farm experiments were conducted in farmers’ fields at 12 different sites in the 2 districts of Moshi and Rombo in northern Tanzania during the 2000–01 cropping season to study the effects of (brady)rhizobial inoculation in combination with P supply on growth and grain yields of soybean and common bean, and to assess the economic returns of these different technologies to farmers. A low level of N was included as an indicator of endogenous soil N status. The treatments included (brady)rhizobial inoculation, N fertilisation (30 kg N/ha as urea), P application [26 kg P/ha as triple super phosphate (TSP)], (brady)rhizobial inoculation + P fertilisation (26 kg/ha as TSP) and unfertilised uninoculated control. The study was conducted as a randomised complete block design with each of the 12 farmers’ fields as a replicate. At harvest, plant growth of soybean and common bean was significantly (P≤0.05) greater with (brady)rhizobial inoculation compared with N and P supply or uninoculated control in the 2 districts. Relative to uninoculated unfertilised plots, grain yields of common bean were markedly (P≤0.05) increased by 60–78% from inoculation alone, and 82–95% from inoculation + 26 kg P/ha; with soybean there was 127–139% increase in grain yield from inoculation alone, and 207–231% from inoculation + P. Thus, the combined application of bacterial inoculants and P fertiliser to field plants of soybean and common bean significantly (P≤0.05) increased biomass production and grain yield compared with the single use of N and P or (brady)rhizobial strains. From economic analysis, the increase in grain yield with inoculation translated into a significantly (P≤0.05) higher marginal rate of return and dollar profit for soybean and common bean farmers in northern Tanzania. With common bean, there was a 66 and 92% increase, respectively, in dollar profit with inoculation at Moshi and Rombo districts respectively relative to control; these profit margins rose to 84 and 102% with provision of supplemental P (26 kg P/ha). With soybean, however, the increase in profit with inoculation was much larger, about 140 and 153% at Rombo and Moshi, respectively, and these rose to 224 and 250% with P supply.
Stat-mediated Signaling Induced by Type I and Type II Interferons (IFNs) Is Differentially Controlled through Lipid Microdomain Association and Clathrin-dependent Endocytosis of IFN Receptors
Authors: Marchetti Marta , Monier Marie-Noelle , Fradagrada Alexandre , Mitchell Keith , Baychelier Florence , Eid Pierre , Johannes Ludger , Lamaze Christophe
Published: April 2006

Type I (α/β) and type II (γ) interferons (IFNs) bind to distinct receptors, although they activate the same signal transducer and activator of transcription, Stat1, raising the question of how signal specificity is maintained. Here, we have characterized the sorting of IFN receptors (IFN-Rs) at the plasma membrane and the role it plays in IFN-dependent signaling and biological activities. We show that both IFN-α and IFN-γ receptors are internalized by a classical clathrin- and dynamin-dependent endocytic pathway. Although inhibition of clathrin-dependent endocytosis blocked the uptake of IFN-α and IFN-γ receptors, this inhibition only affected IFN-α–induced Stat1 and Stat2 signaling. Furthermore, the antiviral and antiproliferative activities induced by IFN-α but not IFN-γ were also affected. Finally, we show that, unlike IFN-α receptors, activated IFN-γ receptors rapidly become enriched in plasma membrane lipid microdomains. We conclude that IFN-R compartmentalization at the plasma membrane, through clathrin-dependent endocytosis and lipid-based microdomains, plays a critical role in the signaling and biological responses induced by IFNs and contributes to establishing specificity within the Jak/Stat signaling pathway.
CREATION OF A SEPARATE TELECOM REGULATORY AGENCY: A DURATION ANALYSIS OF ITS TIME PATTERN
Authors: LEE SANG H. , LEVENDIS JOHN
Published: April 2006

At the center of the issues set out in the 1997 WTO Agreement on Basic Telecommunication Services was the creation of separate telecom regulatory agencies. Using the Cox proportional hazards model, this study examines how a country's socioeconomic factors affect the country's incentive to reorganize its regulatory structure and create a separate telecom regulatory agency. The main empirical findings suggest that a country's incentive to institute a separate telecom regulatory body is greater when its telecom sector performance is relatively poor and its political environment is more competitive with few institutional barriers. (JELL52, L96)
Pseudoxanthomonas kalamensis sp. nov., a novel gammaproteobacterium isolated from Johnston Atoll, North Pacific Ocean
Authors: Harada Renee M. , Campbell Sonia , Li Qing X.
Published: April 2006

An aerobic, mesophilic bacterium, strain JA40T, was isolated from soil contaminated with polycyclic aromatic hydrocarbons and polychlorinated biphenyls collected from Johnston Atoll in the North Pacific Ocean. The strain formed yellow-pigmented colonies on heterotrophic media. The cells were Gram-negative, non-motile, non-sporulating rods. The strain reduced nitrite to nitrous oxide, the DNA G+C content was 64 mol% and the dominant fatty acids were 15 : 0 iso, 17 : 1 isocis7 and 11 : 0 iso 3-OH. DNA sequencing of 1457 nt of the 16S rRNA gene established that JA40Tbelongs in the genusPseudoxanthomonaswithin theXanthomonadaceaebranch of theGammaproteobacteria. Strain JA40Tcan be differentiated from other mesophilic species in the genus on the basis of its physiological and biochemical characteristics and distinctive fatty acid profile. Thus strain JA40T(=ATCC BAA-1031T=CIP 108476T) is the type strain of a novel species of the genusPseudoxanthomonas, for which the namePseudoxanthomonas kalamensissp. nov. is proposed.
Ignisphaera aggregans gen. nov., sp. nov., a novel hyperthermophilic crenarchaeote isolated from hot springs in Rotorua and Tokaanu, New Zealand
Authors: Niederberger Thomas D. , Götz Dorothee K. , McDonald Ian R. , Ronimus Ron S. , Morgan Hugh W.
Published: April 2006

Consortia containing a novel coccus-shaped, anaerobic heterotroph together withPyrobaculumrods were cultivated from geothermal environments in New Zealand. Pure cultures of the cocci were only obtained from one such consortium, despite extensive attempts. Cells of this strain (AQ1.S1T) were regular to irregular cocci in morphology and occasionally formed large aggregates, especially when utilizing polysaccharides such as konjac glucomannan as a carbon source. Strain AQ1.S1Tis a hyperthermophile, with an optimal temperature for growth between 92 and 95 °C (range 85–98 °C), and a moderate acidophile, with optimal growth occurring at pH 6.4 (range 5.4–7.0). Growth was inhibited by the addition of sulphur and NaCl (optimal growth occurred without addition of NaCl) and an electron acceptor was not required. Strain AQ1.S1Tutilized starch, trypticase peptone, lactose, glucose, konjac glucomannan, mannose, galactose, maltose, glycogen andβ-cyclodextrin as carbon sources. The G+C content was 52.9 mol%. Based on 16S rRNA gene sequence analysis and physiological features it is proposed that isolate AQ1.S1T(=DSM 17230T=JCM 13409T) represents the type strain of a novel species of a new genus within theCrenarchaeota,Ignisphaera aggregansgen. nov., sp. nov.
Vulcanibacillus modesticaldus gen. nov., sp. nov., a strictly anaerobic, nitrate-reducing bacterium from deep-sea hydrothermal vents
Authors: L'Haridon S. , Miroshnichenko M. L. , Kostrikina N. A. , Tindall B. J. , Spring S. , Schumann P. , Stackebrandt E. , Bonch-Osmolovskaya E. A. , Jeanthon C.
Published: April 2006

A novel anaerobic, moderately thermophilic, spore-forming bacterium, designated strain BRT, was isolated from deep-sea hydrothermal core samples collected at the Rainbow vent field on the Mid-Atlantic Ridge (36° 14′ N 33° 54′ W). The cells were found to be rod-shaped, non-motile, Gram-positive and spore-forming. The organism grew in the temperature range 37–60 °C, with an optimum at 55 °C, and at pH values in the range 6–8.5, with an optimum around pH 7. NaCl concentrations for growth were in the range 10–40 g l−1, with an optimum at 20–30 g l−1. Strain BRTgrew chemo-organoheterotrophically with carbohydrates, proteinaceous substrates and organic acids with nitrate as electron acceptor. The novel isolate was not able to ferment. The G+C content of the genomic DNA was 34.5 mol%. Phylogenetic analysis of the 16S rRNA gene sequence placed strain BRTin theBacillaceaewithin the class ‘Bacilli’. On the basis of the phenotypic and phylogenetic data, this isolate should be described as a member of a novel genus, for which the nameVulcanibacillusgen. nov. is proposed. The type species isVulcanibacillus modesticaldussp. nov., with the type strain BRT(=DSM 14931T=JCM 12998T).
Azonexus caeni sp. nov., a denitrifying bacterium isolated from sludge of a wastewater treatment plant
Authors: Quan Zhe-Xue , Im Wan-Taek , Lee Sung-Taik
Published: April 2006

A polyphasic taxonomic study was carried out to determine the taxonomic position of a newly isolated denitrifying bacterium, designated Slu-05T, which had been isolated from sludge from the main aerobic treatment tanks of a municipal sewage treatment plant. Phylogenetic analysis based on comparative 16S rRNA gene sequencing indicated that strain Slu-05T was closely related to Azonexus fungiphilus LMG 19178T (96.4 % sequence similarity), the sole species in the genus Azonexus. Strain Slu-05T comprised Gram-negative, motile, non-spore-forming and slightly curved rods. The predominant respiratory lipoquinone was Q-8. The major fatty acids were C16 : 1
ω7c, C16 : 0, C18 : 1 isomers and C10 : 0 3-OH. The G+C content of the genomic DNA was 65.6 mol%. The results of DNA–DNA hybridization (15.6 %) together with phenotypic determination showed that strain Slu-5T could be distinguished from A. fungiphilus. Moreover, some phenotypic properties concerning enzyme activity, the substrates utilized as carbon sources and growth conditions distinguish strain Slu-5T from A. fungiphilus. On the basis of the results obtained in this study, Slu-05T (=DSM 17719T=KCTC 12530T=CCBAU 10199T) is the type strain of a novel species of Azonexus, for which the name Azonexus caeni sp. nov. is proposed.
Bacteroides finegoldii sp. nov., isolated from human faeces
Authors: Bakir Mohammad Abdul , Kitahara Maki , Sakamoto Mitsuo , Matsumoto Mitsuharu , Benno Yoshimi
Published: April 2006

Two strains, 199Tand 176, of Gram-negative, anaerobic, rod-shaped, non-spore-forming bacteria were isolated during studies of microbiota in human faeces using polyamine-deficient medium. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolated strains belonged to the genusBacteroides. The G+C content (42.4–43.0 mol%) and major fatty acid composition (anteiso-C15 : 0, 31.8–36.2 %) supported the affiliation of the two strains to the genusBacteroides. 16S rRNA gene sequence similarities with their closest neighbours,Bacteroides thetaiotaomicronandBacteroides ovatus, ranged from 94.6 to 96.5 %. DNA–DNA hybridization and phenotypic analysis showed that the two strains belonged to the same species (DNA–DNA relatedness of 89 %) and were distinct from their close relatives,B. thetaiotaomicronandB. ovatus(<23 % DNA–DNA relatedness). On the basis of these data, a novel species of the genusBacteroides,Bacteroides finegoldiisp. nov., is proposed, comprising the designated type strain 199T(=JCM 13345T=DSM 17565T) and strain 176 (=JCM 13346).
Photobacterium halotolerans sp. nov., isolated from Lake Martel in Spain
Authors: Rivas Raúl , García-Fraile Paula , Mateos Pedro F. , Martínez-Molina Eustoquio , Velázquez Encarna
Published: April 2006

A halotolerant bacterium was isolated from a saline lake located in Mallorca, Spain. Cells of the strain, designated MACL01T, were Gram-negative, rod-shaped and motile by means of polar flagella. Colonies of strain MACL01Twere white to cream in TSA medium, turning brown after 7 days of incubation; they were blue in thiosulphate/citrate/bile salts/sucrose agar medium. A neighbour-joining phylogenetic analysis based on 16S rRNA gene sequences showed that strain MACL01Tbelongs to the genusPhotobacterium, in which it forms a distinct lineage together withPhotobacterium rosenbergiiandPhotobacterium ganghwense(showing 96.9 and 96.2 % similarity, respectively). The most closely related taxon according to phylogenetic analysis of therpoAgene is alsoP. rosenbergii(90 % similarity). TherecAgene also showed low similarity (83.7, 83.4 and 82.4 %, respectively) with respect to those ofVibrio proteolyticusLMG 3772T,Photobacterium leiognathiiLMG 4228TandP. rosenbergiiLMG 22223T. Neighbour-joining phylogenetic analysis of therpoAandrecAgenes confirms that strain MACL01Tbelongs to the genusPhotobacterium, forming a branch together withP. rosenbergii. Strain MACL01Twas able to grow in 0–8 % NaCl. Growth occurred between 4 and 37 °C (optimum, 28 °C) and at pH 5–8.5. Luminescence was negative on marine agar. Strain MACL01Twas found to be sensitive to the vibriostatic agent O/129. It reduced nitrate to nitrite, producedβ-galactosidase and hydrolysed gelatin, but did not produce arginine dihydrolase, indole or acetoin. Strain MACL01Tused several carbohydrates and fermented glucose,l-arabinose and sucrose. The most abundant fatty acids were summed feature 3 (32.6 %; comprising C16 : 1ω7cand/or C15 : 0iso 2-OH), C16 : 0(21.2 %) and C18 : 1ω7c(19.9 %). The G+C content of the genomic DNA was 49.8 mol%. On the basis of genotypic, phenotypic, chemotaxonomic and phylogenetic results, strain MACL01T(=LMG 22194T=CECT 5860T) should be classified as the type strain of a novel species of the genusPhotobacterium, for which the namePhotobacterium halotoleranssp. nov. is proposed.
Reclassification of [Flavobacterium] ferrugineum as Terrimonas ferruginea gen. nov., comb. nov., and description of Terrimonas lutea sp. nov., isolated from soil
Authors: Xie Cheng-Hui , Yokota Akira
Published: April 2006

Strain DYT, which was isolated from garden soil in Japan, was subjected to a polyphasic taxonomic study. Sequence analysis of the 16S rRNA gene and the GyrB protein revealed that the closest relative of strain DYT was [Flavobacterium] ferrugineum Sickles and Shaw 1934, with 94.8 and 90.1 % similarity, respectively. The two strains had similar chemotaxonomic characteristics, with menaquinone 7 as the major quinone system, 47.2–48.9 mol% DNA G+C content and 15 : 0 iso, 15 : 1 iso, 17 : 0 iso 3-OH and summed feature 3 as the major fatty acids. Based on genotypic and phenotypic characteristics, [Flavobacterium] ferrugineum IAM 15098T could be clearly differentiated from other members of the genus Flavobacterium. Strain DYT and [Flavobacterium] ferrugineum IAM 15098T could be easily distinguished from neighbouring taxa by morphological features (non-motile, non-gliding and non-filamentous single cells). Therefore, it is proposed that [Flavobacterium] ferrugineum IAM 15098T and strain DYT represent two separate species of a new genus, Terrimonas gen. nov., with the names Terrimonas ferruginea comb. nov. (type species; type strain IAM 15098T=ATCC 13524T) and Terrimonas lutea sp. nov. (type strain DYT=IAM 15284T=CCTCC AB205006T), respectively.
Psychroserpens mesophilus sp. nov., a mesophilic marine bacterium belonging to the family Flavobacteriaceae isolated from a young biofilm
Authors: Kwon Kae Kyoung , Lee Soon Jae , Park Jae Hyun , Ahn Tae-Young , Lee Hong Kum
Published: April 2006

A number of marine bacteria isolated from young biofilms were characterized as belonging to the familyFlavobacteriaceae. The taxonomic characterization of strain KOPRI 13649T, which was isolated from an acrylic surface at the seashore at Gangneung, Korea, is reported here. The nearly complete 16S rRNA gene sequence of strain KOPRI 13649Twas determined and was found to have a high level of similarity with that ofPsychroserpens burtonensis(95.0–95.6 %). In addition, phylogenetic analysis and comparison with closely related strains confirmed that the strain represented a novel member of the genusPsychroserpens. The major respiratory quinone of strain KOPRI 13649Twas MK-6 and the DNA G+C content was 29.8 mol%. The dominant fatty acid methyl esters were i-15 : 0, a-15 : 0, i-16 : 0, i-15 : 1ω10, 16 : 1ω7 and 15 : 0. Growth was observed at 10–34 °C (optimum 30 °C), at pH 6–9 (optimum 6.5–8.0) and with 0.5–4 % NaCl (optimum 1 %). On the basis of the polyphasic taxonomic evidence presented, strain KOPRI 13649T(=KCCM 42261T=JCM 13413T) should be classified as the type strain of a novel species in the genusPsychroserpens, for which the namePsychroserpens mesophilussp. nov. is proposed.
Severe infections in thalassaemic patients: prevalence and predisposing factors
Authors: Rahav Galia , Volach Vania , Shapiro Mervyn , Rund Deborah , Rachmilewitz Eliezer A. , Goldfarb Ada
Published: April 2006

The incidence of infections among patients with thalassaemia and the role of risk factors for infection are uncertain. We studied the occurrence of infections necessitating hospitalisation in 92 homozygous β‐thalassaemia patients who had been followed longitudinally for decades, and investigated the role of potential risk factors for these infections. Pneumonia accounted for 26% of the infections and fever of unknown origin for 14%. Staphylococcus aureus was the major pathogen possibly related to injections associated with intensive chelation with deferoxamine. There was a significant increase in the rate of infection over time, notably after 15 years. Splenectomy correlated with the incidence of infection (P < 0·001) without being confounded by other variables and with highest frequencies of infections present after 10 years. A direct correlation between iron overload and infection was evident only before the initiation of iron‐chelating treatment (P < 0·01). Following initiation of deferoxamine, paradoxically, the infection rate increased (P = 0·046). The combination of splenectomy and deferoxamine treatment was associated with the highest adjusted infection rate. Parathyroid dysfunction and glucose‐6‐phosphate dehydrogenase deficiency were significantly associated with infection (P = 0·02 and P = 0·04 respectively). The infection rate in thalassaemia is affected mainly by the duration of the disease and is increased by splenectomy and, in the long term, by treatment with deferoxamine.
Yolk antioxidants and mate attractiveness in the Zebra Finch
Authors: WILLIAMSON K. A. , SURAI P. F. , GRAVES J. A.
Published: April 2006

Egg laying is costly for birds, as eggs must contain all the energy and nutrients needed by the developing embryo. As nutrients are limiting, there is a conflict between provisioning eggs and conserving nutrients for future health and survival.

Life‐history theory suggests that females should choose how to invest resources in relation to the value of the reproductive attempt. Females may manipulate egg composition in relation to the attractiveness of their mate, ensuring chick survival and assuming that the offspring will themselves be more attractive and have higher reproductive success. Antioxidants are an important component of egg composition: they are vital for embryonic and posthatching chick development and survival.

Here we demonstrate that female Zebra Finches (Taeniopygia guttata) mated to attractive males deposit more carotenoids and alpha‐tocopherol (vitamin E) in later‐laid eggs, shown by a significant interaction between laying order and antioxidant concentration. This bias may increase the probability of chick survival from later‐laid eggs and potentially the lifetime reproductive success of the laying female.

The body condition of the laying female, measured as fat reserves, was found to be a significant predictor of yolk carotenoid concentration but not of yolk alpha‐tocopherol concentration.