bluuebunny/crossref_metadata_2025 huggingface dataset:
A work‐oriented occupational therapy programme for individuals with physical disabilities
Authors: Jang Yuh , Hwang Mann‐Tsong , Li Wenshu
Published: April 2006

A Work‐Oriented Occupational Therapy Programme (WOOTP) for individuals with physical disabilities at the Department of Occupational Therapy, National Taiwan University Hospital, is described. The primary goal of the programme is to return the individuals with physical disabilities to work settings and community re‐entry. The programme includes prevocational evaluation and training, functional capacity evaluation, physical capacity evaluation, job site evaluation, and work‐related behaviours and skills training. One hundred and twelve participants completed the therapeutic work programme between November 1995 and May 1997. On outcome, 90 days after discharge, 54 (48.2%) of the clients returned to competitive work, attended school, returned to homemaker activities, or participated in vocational training. The identified strengths of the programme are: it was an integral part of the rehabilitation process; the programme helped clients to confront their disability and psychosocial dysfunction directly through the individual or group discussion and therapy. Copyright © 1997 Whurr Publishers Ltd.
Simultaneous Modeling of the Kovats Retention Indices on Phenyl OV Stationary Phases with Different Polarity using MLR and ANN
Authors: Ebrahimi P. , Hadjmohammadi M. R.
Published: April 2006

A QSRR study was performed to develop a predictive model correlating the observed kovats retention indices of three congeneric aromatic series with their molecular structures in gas chromatography. The congeneric aromatic series included the substituted benzene, benzaldehyde and acethophenone compounds, which had been studied, previously, on six OV stationary phases with different phenyl percentages. At first, a model was generated for six columns separately, using only calculated descriptors and MLR technique. Then a combined model, added a polarity term of stationary phase (M), was also developed for all these columns, and the result was apparently satisfactory (R2=0.991, F=1009.828, SE=23.98). Since the intercept had a high value in this model, the neural network back propagation algorithm was applied for comparison, and it was found that the neural network could exceed the level of the multiple regression method. The stability and validity of both models were tested by cross‐validation technique and by predicted response values for the prediction set and test set. The results of the study indicated that a seven parameter equation can be utilized for prediction of retention indices of compounds on different OV stationary phases simultaneously using ANN technique, for which there are no empirical RI values.
Prognostic Significance of Disseminated Tumor Cells in the Connective Tissue of Patients with Medullary Thyroid Carcinoma
Authors: Gimm Oliver , Heyn Viola , Krause Ulf , Sekulla Carsten , Ukkat Jörg , Dralle Henning
Published: April 2006

Introduction

Disseminated tumor cells in the connective tissue (CT‐DTCs) do not have any connection to a primary tumor or the lymph nodes. They are identified quite often in patients with medullary thyroid carcinoma (MTC), but nothing is known regarding their prognostic significance.

Methods

Among 450 patients with MTC, 69 (15%) were identified as having CT‐DTCs. A case‐control group of patients without CT‐DTCs was selected. The two groups were matched concerning TNM classification, age, heredity, and sex. Because many patients with CT‐DTCs had extrathyroidal tumor extension (pT4 category), distant metastases (M1 category), or both, only 35 matched pairs could be identified. The TNM classification in both groups was as follows: pT1, n = 8; pT2, n = 15; pT3, n = 4; pT4, n = 8; pN0, n = 4; pN1, n = 31; M0, n = 30; M1, n = 5. The mean age was 46.8 ± 17.0 years in the CT‐DTC group and 44.4 ± 15.0 years in the case‐control group (NS).

Results

In both groups, 23 patients had sporadic MTC, and 12 patients had hereditary MTC. Neither mean basal preoperative nor postoperative calcitonin levels differed significantly between the two groups. In contrast, none of the patients with CT‐DTCs was biochemically cured (normal calcitonin level after pentagastrin stimulation) compared to eight patients without CT‐DTCs (P < 0.005). The two groups did not differ concerning other parameters (basal calcitonin level >3000 pg/ml, more than 10 lymph node metastases, more than two involved locoregional lymph node compartments, mediastinal lymph node metastases) that have been reported to correlate with the lack of or almost (<10%) lack of biochemical cure.

Conclusions

In patients with MTC, disseminated tumor cells in the connective tissue correlate with advanced tumor stages and appear to be of prognostic significance.
Differential RNA Expression Profile by cDNA Microarray in Sporadic Primary Hyperparathyroidism (pHPT): Primary Parathyroid Hyperplasia versus Adenoma
Authors: Velázquez‐Fernández David , Laurell Cecilia , Saqui‐Salces Milena , Pantoja Juan Pablo , Candanedo‐Gonzalez Fernando , Reza‐Albarrán Alfredo , Gamboa‐Dominguez Armando , Herrera Miguel F.
Published: April 2006

Background

Differential diagnosis between adenoma and hyperplasia in primary hyperparathyroidism (pHPT) remains a dilemma. The aim of this study was to assess differences in transcriptional genomic expression profiles between sporadic (nonfamilial) parathyroid hyperplasia (SPH), adenoma, and normal tissue.

Methods

Parathyroid tissue from 12 patients with parathyroid adenoma, 3 with SPH, and 2 with normal glands was selected for analysis. Histopathology was reviewed in all cases, and all patients with adenomas presented normocalcemia for a minimum of 6 months after one gland resection. Hybridizations were performed in a microarray containing 19,968 human cDNA clones including contiguous replicates. Direct comparisons were performed with reverse labeling for every different pooled sample entity. Expression levels were analyzed using the SAM, SMA, LIMMA, Cluster, and PAM packages in the R environment for statistical computing.

Results

There were significant statistical differences between SPH and adenomas. In the direct comparison, a total of 200 genes showed differential expression (P < 0.03): 61 genes were upregulated (> 1.65‐fold increase) and 139 were downregulated (> 1.58‐fold decrease) with a B value > 4.68 (99.08% probability of real differential expression). When SPH was compared to normal parathyroid tissue, 50 genes were differentially expressed: 42 were upregulated (> 1.89) and 8 were downregulated (> 1.7) with a B > 4.26 (98.6% probability of real differential expression). At least 17 genes were differentially expressed and able to discriminate SPH from adenoma or normal tissue. Upregulated genes were related to apoptosis inhibition, cell proliferation, transcriptional activity and cell adhesion, among other activities. Downregulated genes were mainly related to ion channel activity, lipopolysaccharides, prostaglandin‐d synthase, and integral membrane proteins.

Conclusions

Our data suggest that SPH and adenoma have a singular molecular signature that, theoretically, could be used for the differential diagnosis of these entities and normal parathyroid tissue.
Trophic ecology of the Patagonian skate, Bathyraja macloviana, on the Argentine continental shelf
Authors: Scenna L.B. , García de la Rosa S.B. , Díaz de Astarloa J.M.
Published: April 2006

The diet, feeding strategy, and dentition of the Patagonian skate, Bathyraja macloviana, on the northern continental shelf of Argentina were studied from specimens collected during research cruises in September and October 2001. Of a total of 81 stomachs examined, only 3.7% were empty. Cumulative prey curves showed that sample sizes were adequate to describe the main prey items of the diet. Quantitative analysis, a graphical method, and trophic niche breadth indicated the species to be a specialized feeder. The most important prey items were polychaetes, followed by gammarid amphipods, isopods, and crabs. Cumaceans, ophiuroids, and hydrozoans were likely incidentally consumed by mature females. Sexual dimorphism in dentition was observed; mature males had longer and sharper tooth cusps than females or immature males. However, there was a high degree of dietary overlap between mature males and mature females, indicating that dental sexual dimorphism in the species is more important in reproductive behaviour than in differential prey consumption.
Liquid Handling with Adaptive Real-Time Validation
Authors: Wendel Gregory J.
Published: April 2006

In the modern drug discovery, clinical, and forensic laboratories, there is an ever-increasing requirement for validation of every aspect of laboratory operations. The proper functioning of the liquid handlers, which are at the center of many of these operations, is crucial because a single mistake may lead to missing a compound that is a potentially important drug candidate. Two new instruments have been developed, which overcome this shortcoming and have other attractive features. The Sciclone inLI0 and Sciclone i 1000 liquid handlers incorporate microflowmeters in each dispensing channel giving them the unique ability to validate each and every liquid handling function, pinpointing problems when they happen. The inclusion of the microflowmeters provides closed-loop control over all liquid handling functions and data on all executed functions. Each of the 96 fluidic channels is essentially an independent liquid handling channel meaning that 96 different volumes can be aspirated/ dispensed simultaneously enabling one-step plate normalizations and other variable volume assays. The Sciclone inLIO covers a volume range from 20 nL to 10 μL with fixed cannula whereas the Sciclone i 1000 uses disposable tips across a range from 5 to 1000 μL. Coefficient of variances have been shown to be below 3% at the upper volume range and approach 8% at 20 nL.
The Use of a Dual Dye Photometric Calibration Method to Identify Possible Sample Dilution from an Automated Multichannel Liquid-handling System
Authors: Dong Huijin , Ouyang Zheng , Liu Jane , Jemal Mohammed
Published: April 2006

A significant difference between the reported volumes delivered by a fluid-filled automated liquid-handling system with eight stainless steel fixed tips was observed when a gravimetric method and a dual dye photometric method were used to measure delivered volumes between 20 and 200 μL. A series of experiments, using the default pipetting parameters, was performed which demonstrated that the difference in the reported volume was due to a dilution effect by the system liquid of the liquid handler and did not indicate an error in the delivered volumes. This dilution effect led to a decrease in the reported volume by the dual dye method, which alerted the user to the problem of sample dilution. In contrast, the gravimetric method provided the expected volume, and therefore did not alert the user to the problem. Without optimization of pipetting parameters, the dilution issue can be significant, because the resultant change in the concentration of the compound(s) of interest in the sample could lead to an unidentified error in the sample assay.
Supplier development: Improving supplier performance through knowledge transfer
Authors: Modi Sachin B. , Mabert Vincent A.
Published: April 2006

The dynamic business environment today requires organizations to effectively use all available resources to remain competitive. The quality and cost of a product or service offered in the market is a function, not only of the capabilities of the firm, but also the supplier network providing inputs to the enterprise. To remain competitive, organizations are increasingly implementing supplier development programs to maintain capable and high performance supply bases. This paper presents a conceptual model of an organization's efforts to improve supplier performance. Then latent variable structural equation modeling (LVSEM) is used to test the model with data for 215 supplier development experiences from US manufacturing firms. The results suggest that evaluation and certification efforts are the most important supplier development prerequisites before undertaking operational knowledge transfer activities such as site visits and supplier training. Furthermore, collaborative inter‐organizational communication is identified as important supporting factor in transforming an organization's efforts to develop suppliers into supplier performance improvements.
Carrying the Burden of Representation: Paul Auster's The Book of Illusions
Authors: PEACOCK JIM
Published: April 2006

The most important thing in art is The Frame. For painting: literally; for other arts: figuratively – because, without this humble appliance, you can't know where The Art stops and The Real World begins. You have to put a “box” around it because otherwise, what is that shit on the wall?

If John Cage, for instance, says, “I'm putting a contact microphone on my throat, and I'm going to drink carrot juice, and that's my composition,” then his gurgling qualifies as his composition because he put a frame around it and said so. “Take it or leave it, I nowwillthis to bemusic.” After that it's a matter of taste. Without the frame-as-announced, it's a guy swallowing carrot juice.
Radiation damping of inertial oscillations in the upper ocean
Authors: Bell T. H.
Published: April 2006

Turbulent motions within the wind-mixed layer, which is advected by near-surface inertial oscillations, excite internal gravity waves in the underlying ocean layers. Momentum transport in the radiated wave field results in a drag force on the inertial currents. Because the magnitude of the inertial currents is large compared with the turbulence intensity, the resultant rate of dissipation of inertial oscillation energy is approximately equal to the energy flux in the radiated wave field. Using linear internal wave theory, asymptotic results are derived for the energy flux in terms of the Brunt-Väisälä frequency N below the mixed layer, the magnitude U0 of the inertial current, the integral length scale l of the mixed-layer turbulence and the mean-square displacement 〈ζ20〉 of the base of the mixed layer. For representative conditions, we estimate an energy flux of 1-10 erg/cm2 s into relatively short (wavelength of order 2πU0/N) high frequency (of order, but less than, N) internal waves. The resultant decay times for inertial oscillation energy range from a day to a week or so, in agreement with reported observations on the decay of inertial oscillations in the upper ocean. The estimated energy flux is comparable in magnitude to estimates for other internal wave generation mechanisms, indicating that, in addition to being a significant sink of inertial energy, this process may locally represent a significant source of internal wave energy in the open ocean.
On the power laws for turbulent jets, wakes and shearing layers and their relationship to the principle of marginal instability
Authors: Lessen Martin
Published: April 2006

The classical power laws describing the similarity solutions for turbulent jets, wakes and shearing layers are found to determine a fixed turbulent Reynolds number for each flow. The power laws are then derived from the principle of marginal instability without the usual assumptions.
Influence of wave dispersion on vortex pairing in a jet
Authors: Petersen R. A.
Published: April 2006

The geometry of large-scale structures in the turbulent mixing layer of a moderate Reynolds number jet is deduced from measurements of the fluctuating pressure in the hydrodynamic near field. The structures are rings of concentrated vorticity that distort with downstream distance until statistical axisymmetry disappears. The rings are spaced quasi-periodically and coalesce with each other, producing larger spacings. Statistical and flow-visualization techniques are applied to free and forced jets over a range of Reynolds numbers from 5000 to 50000 to demonstrate that rings of a given spacing do not coalesce with each other until they are far enough downstream that the local mixing layer has attained some critical thickness which scales with the wavelength of the vortex pair. Wave dispersion is evaluated as a plausible mechanism for localizing the coalescences. The central feature of the model is the observation that a shear layer is dispersive to wavelengths much longer than its thickness and non-dispersive to shorter waves.
Experiments on the stability of convection rolls in fluids whose viscosity depends on temperature
Authors: Richter Frank M.
Published: April 2006

The stability of two-dimensional convection rolls has been studied as a function of the Rayleigh number, wavenumber and variation in viscosity. The experiments used controlled initial conditions for the wavenumber, Rayleigh numbers up to 25 000 and variations in viscosity up to a factor of about 20. The parameter range of stable rolls is bounded by a hexagonal-cell regime at small Rayleigh numbers and large variations in viscosity. Otherwise, the rolls are subject to the same transitions as have already been studied in fluids of uniform viscosity. The bimodal instability leading to a stable three-dimensional pattern occurs at smaller values of the average Rayleigh number as the variations in viscosity increase. This appears to be a consequence of the low viscosity of the warm thermal boundary layer associated with the original rolls.
Measurement of turbulence quantities in a two-stream mixing layer
Authors: Saiy M. , Peerless S. J.
Published: April 2006

Measurements have been made of the time-mean velocity, all three fluctuating velocity components and the turbulence shear stress in the plane mixing layer produced in an open wind tunnel between two nominally parallel air streams with fairly low turbulence levels. The hot-wire measuring system is described, the evaluation equations derived and the principal results presented.
Thermal-ignition analysis in boundary-layer flows
Authors: Law C. K. , Law H. K.
Published: April 2006

The weakly reactive state leading to the ignition of a steady laminar boundary-layer flow of a combustible mixture over a hot, isothermal, non-permeable, non-catalytic flat plate is studied both numerically and using matched asymptotic analysis in the realistic limit of large activation energy. It is shown that the flow consists of a locally similar diffusive-reactive region next to the plate and a non-similar diffusive-convective region outside it; that the analytic solution obtained reproduces the lower half of the S-shaped ignition-extinction response curve such that ignition is expected to occur when a suitably defined Damköhler number, which increases with the streamwise distance, reaches unity; and that at the point of ignition the heat transfer from the wall vanishes identically. An explicit expression for the minimum distance for ignition to occur is also derived.
On a Tollmien-Schlichting wave packet produced by a turbulent spot
Authors: Wygnanski I. , Haritonidis J. H. , Kaplan R. E.
Published: April 2006

Experimental investigations in the region following the passage of an isolated turbulent spot in a laminar boundary layer reveal the existence of a pair of oblique wave packets. These packets are swept at an angle of approximately 40°, and exhibit frequency and wave speed characteristics in agreement with predictions made for oblique Tollmien-Schlichting waves. No waves exist near the centreline of the spot.

Several observations of the breakdown of this ordered motion into a new turbulent spot are shown. This breakdown is accompanied by the appearance of an intense shear layer inclined to the wall.
On the evolution of packets of water waves
Authors: Ablowitz Mark J. , Segur Harvey
Published: April 2006

We consider the evolution of packets of water waves that travel predominantly in one direction, but in which the wave amplitudes are modulated slowly in both horizontal directions. Two separate models are discussed, depending on whether or not the waves are long in comparison with the fluid depth. These models are two-dimensional generalizations of the Korteweg-de Vries equation (for long waves) and the cubic nonlinear Schrödinger equation (for short waves). In either case, we find that the two-dimensional evolution of the wave packets depends fundamentally on the dimensionless surface tension and fluid depth. In particular, for the long waves, one-dimensional (KdV) solitons become unstable with respect to even longer transverse perturbations when the surface-tension parameter becomes large enough, i.e. in very thin sheets of water. Two-dimensional long waves (‘lumps’) that decay algebraically in all horizontal directions and interact like solitons exist only when the one-dimensional solitons are found to be unstable.

The most dramatic consequence of surface tension and depth, however, occurs for capillary-type waves in sufficiently deep water. Here a packet of waves that are everywhere small (but not infinitesimal) and modulated in both horizontal dimensions can ‘focus’ in a finite time, producing a region in which the wave amplitudes are finite. This nonlinear instability should be stronger and more apparent than the linear instabilities examined to date; it should be readily observable.

Another feature of the evolution of short wave packets in two dimensions is that all one-dimensional solitons are unstable with respect to long transverse perturbations. Finally, we identify some exact similarity solutions to the evolution equations.
On the dispersion relation of random gravity waves. Part 2. An experiment
Authors: Mitsuyasu Hisashi , Kuo Yi-Yu , Masuda Akira
Published: April 2006

Random waves are generated by wind in the first half of a wind-wave flume. The latter half of the flume is kept free from wind to measure the waves unaffected by the wind and wind-generated current. The random waves in the latter area are measured with a linear array of wave gauges, and their phase velocities and coherences are determined by a usual technique of the cross-spectral analysis. The measured results are compared with the nonlinear theory of two-dimensional random waves, which has been presented in part 1 of this paper (Masuda, Kuo & Mitsuyasu 1979). Agreement between the theory and the experiment is satisfactory, and observed characteristics of the phase velocity and coherence of the spectral components can be attributed to the effects of the nonlinearity and angular dispersion of the random waves.
Three-dimensional and multicellular steady and unsteady convection in fluid-saturated porous media at high Rayleigh numbers
Authors: Schubert Gerald , Straus Joe M.
Published: April 2006

In an effort to determine the characteristics of the various types of convection that can occur in a fluid-saturated porous medium heated from below, a Galerkin approach is used to investigate three-dimensional convection in a cube and two-dimensional convection in a square cross-section. Strictly two-dimensional, single-cell flow in a square cross-section is steady for Rayleigh numbers R between 4π2 and a critical value which lies between 300 and 320; it is unsteady at higher values of R. Double-cell, two-dimensional flow in a square cross-section becomes unsteady when R exceeds a value between 650 and 700, and triple-cell motion is unsteady for R larger than a value between 800 and 1000. Considerable caution must be exercised in attributing physical reality to these flows. Strictly two-dimensional, steady, multicellular convection may not be realizable in a three-dimensional geometry because of instability to perturbations in the orthogonal dimension. For example, even though single-cell, two-dimensional convection in a square cross-section is steady at R = 200, it cannot exist in either an infinitely long square cylinder or in a cube. It could exist, however, in a cylinder whose length is smaller than 0.38 times the dimension of its square cross-section. Three-dimensional convection in a cube becomes unsteady when R exceeds a value between 300 and 320, similar to the unicellular two-dimensional flow in a square cross-section. Nusselt numbers Nu, generally accurate to 1%, are given for the strictly two-dimensional flows up to R = 1000 and for three-dimensional convection in cubes up to R = 500. Single-cell, two-dimensional, steady convection in a square cross-section transports the most heat for R < 97; this mode of convection is also stable in square cylinders of arbitrary length including the cube for R < 97. Steady three-dimensional convection in cubes transports more heat for 97 [lsim ] R [lsim ] 300 than do any of the realizable two-dimensional modes. At R [gsim ] 300 the unsteady modes of convection in both square cylinders and cubes involve wide variations in Nu.
The interaction of sound with low Mach number wall turbulence, with application to sound propagation in turbulent pipe flow
Authors: Howe M. S.
Published: April 2006

This paper discusses the influence of turbulence convection on the formation of acoustic momentum and thermal boundary layers over a rigid surface in the presence of a low Mach number wall-turbulence shear flow. Equations which determine the modified boundary-layer profiles are obtained from a consideration of the relaxation of coherent perturbations in the Reynolds stress. These equations can be solved analytically for a wide range of conditions which are investigated in detail. The theory is applied to the problem of sound propagation in fully-developed turbulent pipe flow, and at low Mach numbers good agreement is obtained between predicted acoustic attenuation rates and experimental results available in the literature.
Exact solutions of a three-dimensional nonlinear Schrödinger equation applied to gravity waves
Authors: Hui W. H. , Hamilton J.
Published: April 2006

The three-dimensional evolution of packets of gravity waves is studied using a nonlinear Schrödinger equation (the Davey–Stewartson equation). It is shown that permanent wave groups of the elliptic en and dn functions and their common limiting solitary sech forms exist and propagate along directions making an angle less than ψc= tan−1(1/√2) = 35° with the underlying wave field, whilst, along directions making an angle greater than ψc, there exist permanent wave groups of elliptic sn and negative solitary tanh form. Furthermore, exact general solutions are given showing wave groups travelling along the two characteristic directions at ψcor − ψc. These latter solutions tend to form regions of large wave slope and are used to discuss the waves produced by a ship, in particular the nonlinear evolution of the leading edge of the pattern.
Motion of a sphere in the presence of a plane interface. Part 2. An exact solution in bipolar co-ordinates
Authors: Lee S. H. , Leal L. G.
Published: April 2006

A general solution for Stokes’ equation in bipolar co-ordinates is derived, and then applied to the arbitrary motion of a sphere in the presence of a plane fluid/fluid interface. The drag force and hydrodynamic torque on the sphere are then calculated for four specific motions of the sphere; namely, translation perpendicular and parallel to the interface and rotation about an axis which is perpendicular and parallel, respectively, to the interface. The most significant result of the present work is the comparison between these numerically exact solutions and the approximate solutions from part 1. The latter can be generalized to a variety of particle shapes, and it is thus important to assess their accuracy for this case of spherical particles where an exact solution can be obtained. In addition to comparisons with the approximate solutions, we also examine the predicted changes in the velocity, pressure and vorticity fields due to the presence of the plane interface. One particularly interesting feature of the solutions is the fact that the direction of rotation of a freely suspended sphere moving parallel to the interface can either be the same as for a sphere rolling along the interface (as might be intuitively expected), or opposite depending upon the location of the sphere centre and the ratio of viscosities for the two fluids.
Randomly forced Rayleigh-Bénard convection
Authors: Jhaveri Bharat , Homsy G. M.
Published: April 2006

We consider the onset of Rayleigh–Bénard convection from random fluctuations arising within a fluid. In the specific case in which the fluctuations are thermodynamically determined, we reduce the problem to a random initial value problem for the Fourier modes. For the case of weak nonlinear convection, it is possible to truncate the number of modes and this truncated set is solved both by a Monte Carlo technique and by moment methods for various Rayleigh numbers. We find three stages in the evolution of ordered convection from random fluctuations which correspond to time intervals in which the fluctuations and the nonlinearity have different degrees of importance. It is shown that no simple moment truncation method will succeed and that the time for onset of convection is a mean over a distribution of times for which members of an ensemble exhibit appreciable convective transport.
A numerical study of steady viscous flow past a circular cylinder
Authors: Fornberg Bengt
Published: April 2006

Numerical solutions have been obtained for steady viscous flow past a circular cylinder at Reynolds numbers up to 300. A new technique is proposed for the boundary condition at large distances and an iteration scheme has been developed, based on Newton's method, which circumvents the numerical difficulties previously encountered around and beyond a Reynolds number of 100. Some new trends are observed in the solution shortly before a Reynolds number of 300. As vorticity starts to recirculate back from the end of the wake region, this region becomes wider and shorter. Other flow quantities like position of separation point, drag, pressure and vorticity distributions on the body surface appear to be quite unaffected by this reversal of trends.
Forward diffraction of Stokes waves by a thin wedge
Authors: Yue Dick K. P. , Mei Chiang C.
Published: April 2006

The diffraction of a steady Stokes wave train by a thin wedge with vertical walls is studied when the incident wave is directed along the wedge axis (grazing incidence). Parabolic approximation applied recently by Mei & Tuck (1980) to linear diffraction is extended to this nonlinear case. Significant effects of nonlinearity are found numerically, in particular the sharp forward bending of wave crests near the wedge. The computed features are found to corroborate the existing experiments only qualitatively; the controlling factors in the latter being not completely understood. An analytical model of stationary shock is proposed to approximate the numerical results of Mach stems.
A visual investigation of turbulence in stagnation flow about a circular cylinder
Authors: Sadeh Willy Z. , Brauer Herbert J.
Published: April 2006

A diagnostic visualization study of turbulence in stagnation flow around a circular cylinder was carried out to gain physical insight into the coherent structure of turbulence in flow around a bluff body advanced by the vorticity-amplification theory. The visualization was conducted at a cylinder-diameter Reynolds number of 8 × 103 utilizing titanium dioxide white smoke for an approaching flow containing turbulence at scales larger than the neutral wavelength of the stagnation flow. Analyses of the flow events focused on tracing out the temporal and spatial evolution of a cross-vortex tube outlined by the entrained smoke filaments from its emergence near the stagnation zone through its penetration into the cylinder boundary layer.

The selective stretching of cross-vortex tubes, their streamwise tilting, the emergence of an organized turbulent flow pattern near the stagnation zone, the interaction of the amplified vorticity with the body laminar boundary layer and the growth of a turbulent boundary layer were revealed by the visualization. In particular, the visualization indicated that the cross-vortex tubes conveyed by the diverging stagnation flow constitute a coherent substructure within the overall turbulent flow that is triggered to its fullest manifestation by the stretching mechanism.
An experimental study of the effect of uniform strain on thermal fluctuations in grid-generated turbulence
Authors: Warhaft Z.
Published: April 2006

The effect of homogeneous strain on passive scalar fluctuations, and the resultant evolution of the scalar field when the strain is removed, is experimentally studied by passing thermal fluctuations in decaying grid turbulence through a four-to-one axisymmetric contraction. Using amandoline(Warhaft & Lumley 1978a) to vary the scale size of the initial thermal fluctuations and hence the pre-contraction mechanical/thermal time-scale ratio,r, it is shown, for values ofrgreater than unity, that asris increased so is the post-contraction thermal decay rate, i.e. the contraction does not cause the thermal-fluctuation decay rate to equilibrate to a constant value. In these experiments the post-contraction thermal decay rate is always greater than the pre-contraction decay rate, i.e. the contraction accelerates the thermal-fluctuation decay. Moreover, the mechanical/thermal time-scale ratio in the post-contraction region is driven further from unity. In terms of scale size the uniform strain has the effect of increasing the thermal length scale by an amount equal in value to the contraction ratio if the pre-contraction thermal length scale is comparable to that of the pre-contraction velocity scale. However, if the pre-contraction thermal length scale is smaller than the pre-contraction velocity scale then the effect of the contraction on the thermal scale is less marked. The contraction induces significant negative cross-correlation ρuθbetween the longitudinal velocityuand thermal fluctuations θ even if the pre-contraction cross-correlation is close to zero. The magnitude of ρuθand hence the post-contraction heat flux is varied and the coherence structure is studied. It is shown that the thermal-fluctuation decay rate is insensitive to the magnitude of the heat flux, the latter of which decays rapidly compared to the relatively slow decay of turbulence energy in the post-contraction region. It is also shown that ρuθtends towards zero in this axisymmetric homogeneous flow at a faster rate than in isotropic turbulence. In accord with previous investigations, the return toward isotropy of the velocity field is very slow.
The backwash vortex
Authors: Matsunaga N. , Honji H.
Published: April 2006

A backwash vortex has been observed under waves running up a sloping bed. The vortex is formed at the edge of the swash zone when backwash turns back into an oncoming wave bore. The vortex eroded a bed consisting of glass beads, and formed a step which induced the formation of sand ripples.
A new type of three-dimensional deep-water wave of permanent form
Authors: Saffman Philip G. , Yuen Henry C.
Published: April 2006

A new class of three-dimensional, deep-water gravity waves of permanent form has been found using an equation valid for weakly nonlinear waves due to Zakharov (1968). These solutions appear as bifurcations from the uniform two-dimensional wave train. The critical wave heights are given as functions of the modulation wave vector. The three-dimensional patterns may be skewed or symmetrical. An example of the skewed wave pattern is given and shown to be stable. The results become exact in the limit of very oblique modulations.
On free convection experiments in inclined air layers heated from below
Authors: Ruth Douglas W. , Hollands K. G. T. , Raithby G. D.
Published: April 2006

The heat transfer and free convective motion, in inclined air layers heated from below, for angles of incidence 0 [les ] ϕ [les ] 30°, and Rayleigh numbers 100 < Ra cos ϕ < 10000, are studied experimentally. Results of both heat-transfer measurements and flow-visualization studies are reported. The purpose of the study was to investigate the fact, first noted by Hollands et al. (1976), that the experimental heat-transfer data, for ϕ > 20°, is not a function of the product Ra cos ϕ only, as expected from theoretical consideration. This discrepancy between theory and experiment is here attributed to a hypothesized secondary transition in the convective motion, due primarily to perturbation velocities in the upslope direction. This secondary transition appears to be the same as that predicted theoretically by Clever & Busse (1977); qualitative agreement with their theory is observed.
A Diptych of Comedy and Carnival: Alan Ayckbourn’s House & Garden
Authors: Tucker Stephanie
Published: April 2006

This article examines Alan Ayckbourn’s two linked plays, House & Garden, in the context of an entire career exploring the limits and boundaries of theatrical conventions. As the driving force and artistic director of the Stephen Joseph Theatre, a complex which houses two theatres – a proscenium stage and a theatre-in-the-round – the playwright/director has a flexible, state-of-the-art laboratory in which to experiment with theatrical elements which have always fascinated him. In House & Garden, Ayckbourn stretches stage boundaries in unprecedented ways by writing two plays to be performed simultaneously in two adjacent auditoria – a comedy of manners for the proscenium and a carnivalesque farce for the round. Stephanie Tucker analyzes how this unprecedented dramatic diptych exploits the possibilities of theatrical space, on and offstage, whilst appropriating elements from traditions as various as Greek satyr plays and nineteenth-century drama, and from venues as disparate as the carnival square and the drawing room. This experiment, she argues, forces audiences to re-examine preconceived notions concerning theatre’s relationship to the ‘real’ world, a theme which runs through Ayckbourn’s opus. Stephanie Tucker, who teaches at California State University, Sacramento, has published articles on various aspects of contemporary British and American theatre and is presently engaged upon a book-length study of Ayckbourn’s drama and stagecraft.
Validation study of the Ionosphere Forecast Model using the TOPEX total electron content measurements
Authors: Zhu L. , Schunk R. W. , Jee G. , Scherliess L. , Sojka J. J. , Thompson D. C.
Published: April 2006

As a part of the validation program in the Utah State University Global Assimilation of Ionospheric Measurement (GAIM) project, a newly improved Ionosphere Forecast Model (IFM) was systematically validated by using a large database of TOPEX total electron content (TEC) measurements. The TOPEX data used for the validation are for the period from August 1992 to March 2003, and the total number of 18‐s averaged data is close to 11 million. This model validation work covers a wide range of seasonal (winter, summer, and equinox) and solar (low‐F10.7, median F10.7, and high‐F10.7) conditions as well as all UT variations with the focus on nonstorm time TEC. The validation results indicate that the features of the spatial distribution of the IFM TEC are systematically consistent with those of the TOPEX TEC. The differences between the IFM TEC and the TOPEX TEC are within 20% for almost all locations and conditions. For many conditions, the differences are even below 10%.
Introduction to special section: The Hemispheric Dichotomy of Mars
Authors: Watters Thomas R. , McGovern Patrick J.
Published: April 2006

The hemispheric dichotomy is one the most fundamental and least understood features of Mars. The papers in this special section address aspects of the origin of the crustal dichotomy and the modification and evolution of the dichotomy boundary and the northern lowlands. These studies utilize new data from a variety of instruments on spacecraft operating in Mars orbit and on the surface. This special section is an outgrowth of a two‐day workshop held at the Lunar and Planetary Institute in Houston, Texas.
Characterization of a single‐chain variable fragment (scFv) antibody directed against the human asialoglycoprotein receptor
Authors: Cao Limin , Shen Guanxin , Zhu Yinchang , Wang Weiyu , Zhao Xiaorong , Ye Qing , Zhu Huifen , Lu Zhixian , Si Jin
Published: April 2006

To obtain scFv (single‐chain variable fragment) against human ASGPR (asialoglycoprotein receptor), a human non‐immune phage antibody library was screened with the recombinant CRD (carbohydrate recognition domain) of rCRDH1 (the H1 subunit of human ASGPR). Anti‐rCRDH1 phage clones were obtained after four rounds of screening with rCRDH1‐coated immunotubes and single positive colonies were further selected with the expressed thioredoxin–His‐S tag of the wild‐type pET32c. Two specific anti‐rCRDH1 phage clones (named C1 and C2) were transfected into Escherichia coli HB2151 and induced for secreted expression of scFv antibody. The purified anti‐rCRDH1 C1 and C2 single‐chain antibodies were characterized by immunoblotting and immunohistochemistry. Both antibodies were found to specifically recognize denatured and native forms of the ASGPR and thus could potentially be used as targeting molecules for gene therapy of hepatocellular carcinoma or other liver diseases.
Anomalous metal-to-insulator transition in FeSi films deposited on SiO2∕Si substrates
Authors: Witanachchi S. , Abou Mourad H. , Mukherjee P.
Published: April 2006

In-plane conductivity measurements of FeSi films deposited on boron-doped silicon substrates exhibited an anomalous metal-to-insulator transition near 250K. In the temperature range of 250–215K the resistance of the films increased by more than three orders of magnitude. For temperatures >250K, metallic conductivity consistent with the conductivity of the doped silicon substrate was observed. This indicates an ohmic contact between the film and the silicon substrate across the native SiO2 layer. Below the transition temperature (<250K), the temperature dependence of the resistance implies hopping conduction between localized states that is observed in disordered FeSi films. This metal-to-insulator transition observed in these films suggests switching of the current percolation path from substrate to the film due to a rapid increase in the interfacial resistance. The experimental results agree well with a three-layer model that incorporates an exponentially increasing interfacial resistance with decreasing temperature. The presence of a thin native oxide layer between the deposited film and the silicon substrate is essential for manifestation of the transition. Cross-sectional transmission electron microscopy analysis indicated diffusion of Fe through the oxide barrier and accumulation of Fe at the SiO2∕Si interface. The band bending at the interface resulting from Fermi level pinning due to interface states and the formation of (Fe+∕++B−)0∕+ pairs at the SiO2∕Si interface may be responsible for the observed transition.
Optical properties of monocrystalline CuIn5Se8
Authors: Levcenko S. , Syrbu N. N. , Arushanov E. , Tezlevan V. , Fernández-Ruiz R. , Merino J. M. , León M.
Published: April 2006

Single crystals of CuIn5Se8 have been grown by chemical vapor transport. The crystals show a deviation from stoichiometry. The temperature dependence of their optical absorption spectra was investigated in the temperature range of 10–300K. The variation of the energy gap with temperature was studied by means of a three-parameter thermodynamic model, the Einstein model, and the Pässler model. The values of the band gap at T=0K, a dimensionless constant related to the electron-phonon coupling, an effective and a cutoff phonon energy have been estimated. It was also found that the major contribution of phonons to the shift of Eg vs T in CuIn5Se8 is mainly from optical phonons. The presence of Urbach’s tail just below the band edge in the absorption spectra of CuIn3Se5 has been observed. It was shown that the static structural disorders contribute mainly to the absorption below the direct band gap.
Ab initio study on deactivation pathways of excited 9H-guanine
Authors: Chen Hui , Li Shuhua
Published: April 2006

The complete active space with second-order perturbation theory/complete active space self-consistent-field method was used to explore the nonradiative decay mechanism for excited 9H-guanine. On the π1π* (La1) surface we determined a conical intersection (CI), labeled (S0∕ππ*)CI, between the π1π* (La1) excited state and the ground state, and a minimum, labeled (ππ*)min. For the π1π* (La1) state, its probable deactivation path is to undergo a spontaneous relaxation to (ππ*)min first and then decay to the ground state through (S0∕ππ*)CI, during which a small activation energy is required. On the nN1π* surface a CI between the nN1π* and π1π* (La1) states was located, which suggests that the nN1π* excited state could transform to the π1π* (La1) excited state first and then follow the deactivation path of the π1π* (La1) state. This CI was also possibly involved in the nonradiative decay path of the second lowest π1π* (Lb1) state. On the nO1π* surface a minimum was determined. The deactivation of the nO1π* state to the ground state was estimated to be energetically unfavorable. On the π1σ* surface, the dissociation of the N–H bond of the six-membered ring is difficult to occur due to a significant barrier.
rf-generated ambient-afterglow plasma
Authors: Shakir Shariff , Mynampati Sandhya , Pashaie Bijan , Dhali Shirshak K.
Published: April 2006

Atmospheric pressure plasmas have gained importance due to their potential application in polymer surface treatment, surface cleaning of metals, thin film deposition, and destruction of biological hazards. In this paper a radio-frequency driven atmospheric pressure afterglow plasma source in argon and helium is discussed. The light intensity measurement shows that the radio-frequency discharge is continuous in time unlike the intermittent nature of a low frequency dielectric-barrier discharge. The discharge, under ambient conditions, can be generated in argon, helium, and nitrogen. Spectroscopic measurements show that metastables are capable of producing oxygen atoms and other excited species. The argon afterglow, in particular, is capable of dissociating oxygen molecules in the ambient gas. An afterglow model has been developed to study the interaction of the plasma with the ambient gas. Results from applications of the plasma to surface treatment of metals and polymers, and bacterial decontamination are briefly discussed.
Morphology evolution and photoluminescence properties of ZnO films electrochemically deposited on conductive glass substrates
Authors: Cao Bingqiang , Cai Weiping , Zeng Haibo , Duan Guotao
Published: April 2006

The current-dependent morphology evolution and photoluminescence properties of zinc oxide (ZnO) films prepared by electrochemical deposition (ECD) method were studied in this paper. It has been shown that the morphologies of ZnO films vary from porous to dense structure, from pillar crystal array to two-dimensional nanosheet covered film, with increase of deposition currents. Correspondingly, orientation of the film evolves from randomly to highly c-axis oriented structure. Current dependence of morphology is attributed to the ECD current-controlled preferential growth velocity along the c axis. All the ZnO films prepared over a wide current range show strong ultraviolet (UV) emission at room temperature, which also shows deposition current dependence in intensity, together with relatively weak defect-related green emission under UV excitations. Further experiments have revealed that a nonradiative relax process and a radiative electron-hole combination process are involved in this defect-related green emission and the excitonic origin of UV emission was also proved.