bluuebunny/crossref_metadata_2025 huggingface dataset:
Distributed model of solid waste anaerobic digestion: Effects of leachate recirculation and pH adjustment
Authors: Vavilin Vasily A. , Rytov Sergey V. , Lokshina Ljudmila Ya. , Pavlostathis Spyros G. , Barlaz Morton A.
Published: November 2002

A distributed model of solid waste digestion in a 1‐D bioreactor with leachate recirculation and pH adjustment was developed to analyze the balance between the rates of polymer hydrolysis/acidogenesis and methanogenesis during the anaerobic digestion of municipal solid waste (MSW). The model was calibrated on previously published experimental data generated in 2‐L reactors filled with shredded refuse and operated with leachate recirculation and neutralization. Based on model simulations, both waste degradation and methane production were stimulated when inhibition was prevented rapidly from the start, throughout the reactor volume, by leachate recirculation and neutralization. An optimal strategy to reduce the time needed for solid waste digestion is discussed. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 66–73, 2003.
Increase of the yields of eicosapentaenoic and docosahexaenoic acids by the microalga Pavlova lutheri following random mutagenesis
Authors: Meireles Luís A. , Guedes A. Catarina , Malcata F. Xavier
Published: November 2002

The high commercial values of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids have driven a strain‐improvement program, aimed at increasing the content of those fatty acids in the microalga Pavlova lutheri (SMBA 60) as parent strain. After a round of mutation using UV‐light as mutagenic agent, an isolate strain (tentatively called II#2) was obtained, the EPA and DHA contents of which (in % dry biomass) were 32.8% and 32.9% higher than those of the control, native strain. The final EPA yields, when the cultures were maintained under appropriate conditions, were 17.4 and 23.1 mg · g−1 dry biomass, for the wild‐type and the II#2 strain, respectively, whereas the final DHA yields were 8.0 and 10.6 mg · g−1 dry biomass, respectively. These results suggest that random mutagenesis can successfully be applied to increase the yield of n‐3 fatty acids by microalgae. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 50–55, 2003.
Metabolic flux analysis of cultured hepatocytes exposed to plasma
Authors: Chan Christina , Berthiaume François , Lee Kyongbum , Yarmush Martin L.
Published: November 2002

Hepatic metabolism can be investigated using metabolic flux analysis (MFA), which provides a comprehensive overview of the intracellular metabolic flux distribution. The characterization of intermediary metabolism in hepatocytes is important for all biotechnological applications involving liver cells, including the development of bioartificial liver (BAL) devices. During BAL operation, hepatocytes are exposed to plasma or blood from the patient, at which time they are prone to accumulate intracellular lipids and exhibit poor liver‐specific functions. In a prior study, we found that preconditioning the primary rat hepatocytes in culture medium containing physiological levels of insulin, as opposed to the typical supraphysiological levels found in standard hepatocyte culture media, reduced lipid accumulation during subsequent plasma exposure. Furthermore, supplementing the plasma with amino acids restored hepatospecific functions. In the current study, we used MFA to quantify the changes in intracellular pathway fluxes of primary rat hepatocytes in response to low‐insulin preconditioning and amino acid supplementation. We found that culturing hepatocytes in medium containing lower physiological levels of insulin decreased the clearance of glucose and glycerol with a concomitant decrease in glycolysis. These findings are consistent with the general notion that low insulin, especially in the presence of high glucagon levels, downregulates glycolysis in favor of gluconeogenesis in hepatocytes. The MFA model shows that, during subsequent plasma exposure, low‐insulin preconditioning upregulated gluconeogenesis, with lactate as the primary precursor in unsupplemented plasma, with a greater contribution from deaminated amino acids in amino acid‐supplemented plasma. Concomitantly, low‐insulin preconditioning increased fatty acid oxidation, an effect that was further enhanced by amino acid supplementation to the plasma. The increase in fatty acid oxidation reduced intracellular triglyceride accumulation. Overall, these findings are consistent with the notion that the insulin level in medium culture presets the metabolic machinery of hepatocytes such that it directly impacts on their metabolic behavior during subsequent plasma culture. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 33–49, 2003.
Metabolic model for glycogen‐accumulating organisms in anaerobic/aerobic activated sludge systems
Authors: Zeng Raymond J. , van Loosdrecht Mark C. M. , Yuan Zhiguo , Keller Jürg
Published: November 2002

Glycogen‐accumulating organisms (GAO) have the potential to directly compete with polyphosphate‐accumulating organisms (PAO) in EBPR systems as both are able to take up VFA anaerobically and grow on the intracellular storage products aerobically. Under anaerobic conditions GAO hydrolyse glycogen to gain energy and reducing equivalents to take up VFA and to synthesise polyhydroxyalkanoate (PHA). In the subsequent aerobic stage, PHA is being oxidised to gain energy for glycogen replenishment (from PHA) and for cell growth. This article describes a complete anaerobic and aerobic model for GAO based on the understanding of their metabolic pathways. The anaerobic model has been developed and reported previously, while the aerobic metabolic model was developed in this study. It is based on the assumption that acetyl‐CoA and propionyl‐CoA go through the catabolic and anabolic processes independently. Experimental validation shows that the integrated model can predict the anaerobic and aerobic results very well. It was found in this study that at pH 7 the maximum acetate uptake rate of GAO was slower than that reported for PAO in the anaerobic stage. On the other hand, the net biomass production per C‐mol acetate added is about 9% higher for GAO than for PAO. This would indicate that PAO and GAO each have certain competitive advantages during different parts of the anaerobic/aerobic process cycle. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 92–105, 2003.
A mutant of the green alga Dunaliella salina constitutively accumulates zeaxanthin under all growth conditions
Authors: Jin EonSeon , Feth Brian , Melis Anastasios
Published: November 2002

A novel mutant (zea1) of the halotolerant unicellular green alga Dunaliella salina is impaired in the zeaxanthin epoxidation reaction, thereby lacking a number of the β‐branch xanthophylls. HPLC analysis revealed that the zea1 mutant lacks neoxanthin (N), violaxanthin (V) and antheraxanthin (A) but constitutively accumulates zeaxanthin (Z). Under low‐light physiological growth conditions, the zea1 (6 mg Z per g dry weight or 8 × 10−16 mol Z/cell) had a substantially higher Z content than the wild type (0.2 mg Z per g dry weight or 0.5 × 10−16 mol Z/cell). Lack of N, V, and A did not affect photosynthesis or growth of the zea1 strain. Biochemical analyses suggested that Z constitutively and quantitatively substitutes for N, V, and A in the zea1 strain. This mutant is discussed in terms of its commercial value and potential utilization by the algal biotechnology industry for the production of zeaxanthin, a high‐value bioproduct. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 115–124, 2003.
The response of virally infected insect cells to dissolved oxygen concentration: Recombinant protein production and oxidative damage
Authors: Saarinen Mark A. , Murhammer David W.
Published: November 2002

The effects of dissolved oxygen (DO) concentration on virally infected insect cells were investigated in 3‐L bioreactor culture. Specifically, cultures of Spodoptera frugiperda Sf‐9 (Sf‐9) and Trichoplusia ni BTI‐Tn‐5B1‐4 (Tn‐5B1‐4) were infected with Autographa californica multiple nucleopolyhedrovirus expressing secreted alkaline phosphatase (SEAP). Following infection at a DO concentration of 50% air saturation, the DO concentration was adjusted to a final value of either 190%, 50%, or 10% air saturation. Recombinant SEAP production, cell viability, protein carbonyl content, and thiobarbituric acid reactive substances (TBARS) content were monitored. The increases in protein carbonyl and TBARS contents are taken to be indicators of protein oxidation and lipid oxidation, respectively. DO concentration was found to have no noticeable effect on SEAP production or cell viability decline in the Sf‐9 cell line. In the Tn‐5B1‐4 cell line, cells displayed an increased peak SEAP production rate for 190% air saturation and displayed an increased rate of viability decline at increased DO concentration. Protein carbonyl content showed no significant increase in the Sf‐9 cell line by 72 h postinfection (pi) at any DO concentration but showed a twofold increase at 10% and 50% DO concentration and a threefold increase at 190% DO concentration by 72 h pi in Tn‐5B1‐4 cells. TBARS content was found to increase by ≈ 50% in Sf‐9 cells and by ≈ twofold in Tn‐5B1‐4 cells by 72 h pi with no clear relationship to DO concentration. It is hypothesized that oxygen uptake changes due to the viral infection process may bear a relation to the observed increases in protein and lipid oxidation and that lipid oxidation may play an important role in the death of virally infected insect cells. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 106–114, 2003.
Novel CNBP‐ and La‐based translation control systems for mammalian cells
Authors: Schlatter Stefan , Fussenegger Martin
Published: November 2002

Throughout the development of Xenopus, production of ribosomal proteins (rp) is regulated at the translational level. Translation control is mediated by a terminal oligopyrimidine element (TOP) present in the 5′ untranslated region (UTR) of rp‐encoding mRNAs. TOP elements adopt a specific secondary structure that prevents ribosome‐binding and translation‐initiation of rp‐encoding mRNAs. However, binding of CNBP (cellular nucleic acid binding protein) or La proteins to the TOP hairpin structure abolishes the TOP‐mediated transcription block and induces rp production. Based on the specific CNBP‐TOP/La‐TOP interactions we have designed a translation control system (TCS) for conditional as well as adjustable translation of desired transgene mRNAs in mammalian cells. The generic TCS configuration consists of a plasmid encoding CNBP or La under control of the tetracycline‐responsive expression system (TETOFF) and a target expression vector containing a TOP module between a constitutive PSV40 promoter and the human model product gene SEAP (human secreted alkaline phosphatase) (PSV40‐TOP‐SEAP‐pA). The TCS technology showed excellent SEAP regulation profiles in transgenic Chinese hamster ovary (CHO) cells. Alternatively to CNBP and La, TOP‐mediated translation control can also be adjusted by artificial phosphorothioate anti‐TOP oligodeoxynucleotides. Confocal laser‐scanning microscopy demonstrated cellular uptake of FITC‐labeled oligodeoxynucleotides and their localization in perinuclear organelles within 24 hours. Besides their TOP‐based translation‐controlling capacity, CNBP and La were also shown to increase cap‐independent translation from polioviral internal ribosomal entry sites (IRES) and La alone to boost cap‐dependent translation initiation. CNBP and La exemplify for the first time the potential of RNA‐binding proteins to exert translation control of desired transgenes and to increase heterologous protein production in mammalian cells. We expect both of these assets to advance current gene therapy and biopharmaceutical manufacturing strategies. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 1–12, 2003.
Expression of a plant‐derived peptide harboring water‐cleaning and antimicrobial activities
Authors: Suarez M. , Entenza J. M. , Doerries C. , Meyer E. , Bourquin L. , Sutherland J. , Marison I. , Moreillon P. , Mermod N.
Published: November 2002

Drinking water is currently a scarce world resource, the preparation of which requires complex treatments that include clarification of suspended particles and disinfection. Seed extracts of Moringa oleifera Lam., a tropical tree, have been proposed as an environment‐friendly alternative, due to their traditional use for the clarification of drinking water. However, the precise nature of the active components of the extract and whether they may be produced in recombinant form are unknown. Here we show that recombinant or synthetic forms of a cationic seed polypeptide mediate efficient sedimentation of suspended mineral particles and bacteria. Unexpectedly, the polypeptide was also found to possesses a bactericidal activity capable of disinfecting heavily contaminated water. Furthermore, the polypeptide has been shown to efficiently kill several pathogenic bacteria, including antibiotic‐resistant isolates of Staphylococcus, Streptococcus, and Legionella species. Thus, this polypeptide displays the unprecedented feature of combining water purification and disinfectant properties. Identification of an active principle derived from the seed extracts points to a range of potential for drinking water treatment or skin and mucosal disinfection in clinical settings. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 13–20, 2003.
The segment projection method for interface tracking
Authors: Tornberg Anna‐Karin , Engquist Björn
Published: November 2002

There has recently been important progress in the development of front tracking and level set methods for the numerical simulation of moving interfaces. The segment projection method is a new technique for computational geometry. It can be seen as a compromise between front tracking and level set methods. It is based on the regular mathematical representation of a manifold as an atlas of charts. Each chart or segment is evolved independently by a partial differential equation that is discretized on an Eulerian grid. The connectivity of the segments is handled by an appropriate data structure and by numerical interpolation. The method is presented and its properties are analyzed. Applications to multiphase flow, epitaxial growth, and high‐frequency wave propagation are given. © 2002 Wiley Periodicals, Inc.
Multiscale homogenization with bounded ratios and anomalous slow diffusion
Authors: Ben Arous Gérard , Owhadi Houman
Published: November 2002

We show that the effective diffusivity matrix D(Vn) for the heat operator ∂t − (Δ/2 − ∇Vn∇) in a periodic potential Vn = ΣUk(x/Rk) obtained as a superposition of Hölder‐continuous periodic potentials Uk (of period 𝕋d := ℝd/ℤd, d ∈ ℕ*, Uk(0) = 0) decays exponentially fast with the number of scales when the scale ratios Rk+1/Rk are bounded above and below. From this we deduce the anomalous slow behavior for a Brownian motion in a potential obtained as a superposition of an infinite number of scales, dyt = dωt − ∇V∞(yt)dt. © 2002 Wiley Periodicals, Inc.
On Schrödinger maps
Authors: Nahmod Andrea , Stefanov Atanas , Uhlenbeck Karen
Published: November 2002

We study the question of well‐posedness of the Cauchy problem for Schrödinger maps from ℝ × ℝ2 to the sphere 𝕊2 or to ℍ2, the hyperbolic space. The idea is to choose an appropriate gauge change so that the derivatives of the map will satisfy a certain nonlinear Schrödinger system of equations and then study this modified Schrödinger map system (MSM). We then prove local well‐posedness of the Cauchy problem for the MSM with minimal regularity assumptions on the data and outline a method to derive well‐posedness of the Schrödinger map itself from it. In proving well‐posedness of the MSM, the heart of the matter is resolved by considering truly quatrilinear forms of weighted L2‐functions. © 2002 Wiley Periodicals, Inc.
Extracting macroscopic stochastic dynamics: Model problems
Authors: Huisinga Wilhelm , Schütte Christof , Stuart Andrew M.
Published: December 2002

The purpose of this work is to shed light on an algorithm designed to extract effective macroscopic models from detailed microscopic simulations. The particular algorithm we study is a recently developed transfer operator approach due to Schütte et al. [20]. The investigations involve the formulation, and subsequent numerical study, of a class of model problems. The model problems are ordinary differential equations constructed to have the property that, when projected onto a low‐dimensional subspace, the dynamics is approximately that of a stochastic differential equation exhibiting a finite‐state‐space Markov chain structure. The numerical studies show that the transfer operator approach can accurately extract finite‐state Markov chain behavior embedded within high‐dimensional ordinary differential equations. In so doing the studies lend considerable weight to existing applications of the algorithm to the complex systems arising in applications such as molecular dynamics. The algorithm is predicated on the assumption of Markovian input data; further numerical studies probe the role of memory effects. Although preliminary, these studies of memory indicate interesting avenues for further development of the transfer operator methodology. © 2002 Wiley Periodicals, Inc.
Parenting style and obsessive‐compulsive symptoms and personality traits in a student sample
Authors: Aycicegi Ayse , Harris Catherine L. , Dinn Wayne M.
Published: December 2002

There is widespread acceptance of the idea that aspects of parenting such as overprotectiveness and perfectionism contribute to the pathogenesis of obsessive‐compulsive disorder (OCD). Less resolved is whether the important dimensions of parenting are overprotectiveness, lack of acceptance, authoritarian style, discouragement of risk‐taking, and/or induction of guilt. It is also unclear whether different parenting characteristics are associated with the development of symptoms of OCD, compared to the traits of obsessive‐compulsive personality disorder (OCPD). OCD symptoms and OC personality traits were measured in a non‐clinical, student sample and correlated with students' report of parents' acceptance, disciplinary firmness, and psychological control (a construct which included psychological manipulation and guilt‐induction). Following the literature on both clinical and subclinical OCD and OCPD, we predicted that all three scales would correlate with OCD symptoms and OCPD traits. Stepwise regression analysis revealed that psychological control was the unique predictor, controlling for depressive symptoms. Unexpectedly, a controlling parenting style was not selectively associated with classical OC symptoms or OC personality traits. Rather, psychological control was associated with a broad‐spectrum of anxiety and depressive symptoms which cut across diagnostic boundaries. Findings are generally compatible with a single underlying vulnerability to both OCD and OCPD, as well as generalized/social anxiety and depressive symptoms, which can be shaped by cultural and familial factors to a specific clinical presentation. Copyright © 2002 John Wiley & Sons, Ltd.
Homogeneous and heterogeneous distributed cluster processing for two‐ and three‐dimensional viscoelastic flows
Authors: Baloch A. , Grant P. W. , Webster M. F.
Published: November 2002

A finite‐element study of two‐ and three‐dimensional incompressible viscoelastic flows in a planar lid‐driven cavity and concentric rotating cylinders is presented. The hardware platforms consist of both homogeneous and heterogeneous clusters of workstations. A semi‐implicit time‐stepping Taylor–Galerkin scheme is employed using the message passing mechanism provided by the Parallel Virtual Machine libraries. DEC‐alpha, Intel Solaris and AMD‐K7(Athlon) Linux clusters are utilized. Parallel results are compared against single processor (sequentially) solutions, using the parallelism paradigm of domain decomposition. Communication is effectively masked and practically ideal, linear speed‐up with the number of processors is realized. Copyright © 2002 John Wiley & Sons, Ltd.
Computation of unsteady viscous incompressible flows in generalized non‐inertial co‐ordinate system using Godunov‐projection method and overlapping meshes
Authors: Pan H. , Damodaran M.
Published: November 2002

Time‐dependent incompressible Navier–Stokes equations are formulated in generalized non‐inertial co‐ordinate system and numerically solved by using a modified second‐order Godunov‐projection method on a system of overlapped body‐fitted structured grids. The projection method uses a second‐order fractional step scheme in which the momentum equation is solved to obtain the intermediate velocity field which is then projected on to the space of divergence‐free vector fields. The second‐order Godunov method is applied for numerically approximating the non‐linear convection terms in order to provide a robust discretization for simulating flows at high Reynolds number. In order to obtain the pressure field, the pressure Poisson equation is solved. Overlapping grids are used to discretize the flow domain so that the moving‐boundary problem can be solved economically. Numerical results are then presented to demonstrate the performance of this projection method for a variety of unsteady two‐ and three‐dimensional flow problems formulated in the non‐inertial co‐ordinate systems. Copyright © 2002 John Wiley & Sons, Ltd.
Performance of finite volume solutions to the shallow water equations with shock‐capturing schemes
Authors: Erduran K. S. , Kutija V. , Hewett C. J. M.
Published: November 2002

Numerical methods have become well established as tools for solving problems in hydraulic engineering. In recent years the finite volume method (FVM) with shock capturing capabilities has come to the fore because of its suitability for modelling a variety of types of flow; subcritical and supercritical; steady and unsteady; continuous and discontinuous and its ability to handle complex topography easily.

This paper is an assessment and comparison of the performance of finite volume solutions to the shallow water equations with the Riemann solvers; the Osher, HLL, HLLC, flux difference splitting (Roe) and flux vector splitting. In this paper implementation of the FVM including the Riemann solvers, slope limiters and methods used for achieving second order accuracy are described explicitly step by step. The performance of the numerical methods has been investigated by applying them to a number of examples from the literature, providing both comparison of the schemes with each other and with published results. The assessment of each method is based on five criteria; ease of implementation, accuracy, applicability, numerical stability and simulation time. Finally, results, discussion, conclusions and recommendations for further work are presented. Copyright © 2002 John Wiley & Sons, Ltd.
Energy dynamics in a turbulent channel flow using the Karhunen‐Loéve approach
Authors: Webber G. A. , Handler R. A. , Sirovich L.
Published: November 2002

The dynamical equations for the energy in a turbulent channel flow have been developed by using the Karhunen‐Loéve modes to represent the velocity field. The energy balance equations show that all the energy in the flow originates from the applied pressure gradient acting on the mean flow. Energy redistribution occurs through triad interactions, which is basic to understanding the dynamics. Each triad interaction determines the rate of energy transport between source and sink modes via a catalyst mode. The importance of the proposed method stems from the fact that it can be used to determine both the rate of energy transport between modes as well as the direction of energy flow. The effectiveness of the method in determining the mechanisms by which the turbulence sustains itself is demonstrated by performing a detailed analysis of triad interactions occurring during a turbulent burst in a minimal channel flow. The impact on flow modification is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Analysis of the near‐wall behaviour of some self‐adaptive subgrid‐scale models in finite‐differenced simulations of channel flow
Authors: Sagaut P. , Montreuil E. , Labbé2 O. , Cambon C.
Published: November 2002

Self‐adaptive subgrid‐scale models are proposed and assessed. They are based on the use of the Germano–Lilly dynamic procedure and the use of a selection function. These models, which do not incorporate any information related to the location of the solid walls, are well suited for the simulation of turbulent flows in complex geometries. Their reliability, when used together with a second‐order non‐dissipative numerical method, is assessed on the plane channel configuration for two values of the Reynolds number (Reτ = 180 and 395) for two grid resolutions. The selection function approach for deriving self‐adaptive subgrid models is found to yield results very similar to those obtained using a dynamic model, without requiring any numerical stabilization procedure. The use of the selection function is shown to be the only one which is able to capture the backscatter process in the buffer layer, while producing a strictly positive subgrid viscosity. This is demonstrated to be linked to the capability of the selection function to permit a decorrelation between the mean strain and the fluctuations of the subgrid stresses. That point is illustrated thanks to the introduction of a new decomposition of the fluctuating strain subgrid dissipation. Copyright © 2002 John Wiley & Sons, Ltd.
An approximate projection method for incompressible flow
Authors: Stevens David E. , Chan Stevens T. , Gresho Phil
Published: November 2002

This paper presents an approximate projection method for incompressible flows. This method is derived from Galerkin orthogonality conditions using equal‐order piecewise linear elements for both velocity and pressure, hereafter Q1Q1. By combining an approximate projection for the velocities with a variational discretization of the continuum pressure Poisson equation, one eliminates the need to filter either the velocity or pressure fields as is often needed with equal‐order element formulations. This variational approach extends to multiple types of elements; examples and results for triangular and quadrilateral elements are provided. This method is related to the method of Almgren et al. (SIAM J. Sci. Comput. 2000; 22: 1139–1159) and the PISO method of Issa (J. Comput. Phys. 1985; 62: 40–65). These methods use a combination of two elliptic solves, one to reduce the divergence of the velocities and another to approximate the pressure Poisson equation. Both Q1Q1 and the method of Almgren et al. solve the second Poisson equation with a weak error tolerance to achieve more computational efficiency.

A Fourier analysis of Q1Q1 shows that a consistent mass matrix has a positive effect on both accuracy and mass conservation. A numerical comparison with the widely used Q1Q0 (piecewise linear velocities, piecewise constant pressures) on a periodic test case with an analytic solution verifies this analysis. Q1Q1 is shown to have comparable accuracy as Q1Q0 and good agreement with experiment for flow over an isolated cubic obstacle and dispersion of a point source in its wake. Copyright © 2002 John Wiley & Sons, Ltd.
Optimal control of unsteady compressible viscous flows
Authors: Scott Collis S. , Ghayour Kaveh , Heinkenschloss Matthias , Ulbrich Michael , Ulbrich Stefan
Published: November 2002

The control of complex, unsteady flows is a pacing technology for advances in fluid mechanics. Recently, optimal control theory has become popular as a means of predicting best case controls that can guide the design of practical flow control systems. However, most of the prior work in this area has focused on incompressible flow which precludes many of the important physical flow phenomena that must be controlled in practice including the coupling of fluid dynamics, acoustics, and heat transfer. This paper presents the formulation and numerical solution of a class of optimal boundary control problems governed by the unsteady two‐dimensional compressible Navier–Stokes equations. Fundamental issues including the choice of the control space and the associated regularization term in the objective function, as well as issues in the gradient computation via the adjoint equation method are discussed. Numerical results are presented for a model problem consisting of two counter‐rotating viscous vortices above an infinite wall which, due to the self‐induced velocity field, propagate downward and interact with the wall. The wall boundary control is the temporal and spatial distribution of wall‐normal velocity. Optimal controls for objective functions that target kinetic energy, heat transfer, and wall shear stress are presented along with the influence of control regularization for each case. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of rotation on Goertler vortices in the boundary layer flow on a curved surface
Authors: Chen C. T. , Lin M. H.
Published: November 2002

This paper presents a numerical prediction of the formation of Goertler vortices on a curved surface with effect of rotation. The criterion of flow visualization marking the onset position of Goertler vortices is employed in the present paper. For facilitating the numerical study, the computation is carried out in the transformed x and ηplane. The results show that the onset position characterized by the Goertler number, depends on the rotation number Ro, the Prandtl number and the wave number. The value of critical Goertler number increases with the increase in negative rotation, while the value of Goertler number decreases with the increase in positive rotation on a concave surface. On the contrary, the value of critical Goertler number decreases with the increase in negative rotation on a convex surface. The obtained critical Goertler number and wave number are compared with the previous theoretical and experimental data. Copyright © 2002 John Wiley & Sons, Ltd.
Large‐eddy simulation of a bluff‐body flow on unstructured grids
Authors: Camarri S. , Salvetti M. V. , Koobus B. , Dervieux A.
Published: November 2002

Large‐eddy simulations of the flow around a square cylinder on coarse unstructured grids are investigated. The numerical solver is based on a mixed finite‐volume/finite‐element formulation. A modified Roe scheme is employed for convective terms, together with the MUSCL method to increase the order of accuracy. An upwinding parameter, γs, directly controls the numerical diffusion, which is formed of fourth‐order space derivatives. The eddy‐viscosity Smagorinsky model and its dynamic version are used for the subgrid scale (SGS) terms in the LES equations. The effects of upwinding, and, in particular, the interaction between SGS and numerical dissipation, are studied by varying the value of γs. The sensitivity to grid inhomogeneity and to SGS modelling are also investigated. Results are compared to those obtained in other LES in the literature and to experimental data. Copyright © 2002 John Wiley & Sons, Ltd.
Stochastic volatility and the mean reverting process
Authors: Sabanis Sotirios
Published: November 2002

This article employs an approach that is an extension of the Hull and White (1987) model, for pricing European options under the assumption of a mean reverting
volatility for the underlying asset. The approach uses a Taylor series expansion method to approximate the price
of a European call option in a market with no arbitrage opportunities. The transition to a riskneutral economy is
accomplished by introducing an equivalent martingale measure based on the findings of Romano and Touzi
(1997). Numerical results are obtained and compared with similar studies
(Lewis, 2000). © 2003 Wiley Periodicals, Inc. Jrl Fut Mark
23:33–47, 2003
Does tick size influence price discovery? Evidence from the Toronto Stock Exchange
Authors: Beaulieu Marie‐Claude , Ebrahim Shafiq K. , Morgan Ieuan G.
Published: November 2002

We investigate the price discovery role of an exchange‐traded fund and the futures contract for the
same market index. We find that the fund predicts the index in the subperiod after but not in the subperiod
before a substantial decrease in the minimum tick size. The futures predict the index in both subperiods. The
results are consistent with the view that the factors leading to successful price discovery do not depend on
zero investment, as in futures markets, but do depend on a small tick size. © 2003 Wiley Periodicals, Inc.
Jrl Fut Mark 23:49–66, 2003
Expiration day effects: The case of Hong Kong
Authors: Chow Ying‐Foon , Yung Haynes H. M. , Zhang Hua
Published: November 2002

Regulators around the world often express concerns about the high volatility of stock markets due to index
derivative expirations. Earlier studies of expiration day effects have found large volume effects, abnormal return
volatility, and price effects during the last hour of trading on expiration days when the settlement is based on
the closing price. This article examines the impact of the expiration of Hang Seng Index (HSI)
derivatives on the underlying cash market in Hong Kong for the period from 1990 to 1999. The HSI derivative market
is different from most other markets in the sense that the settlement price is computed by taking the average of
5‐minute quotations of the HSI on the last trading day, thus providing an alternative setting for testing
expiration day effects. Our empirical findings indicate that expiration days in Hong Kong may be associated with a
negative price effect and some return volatility on the underlying stock market, but there is no evidence of
abnormal trading volume on the expiration day, or price reversal after expiration. Thus, the existence of
expiration day effects cannot be confirmed in the Hong Kong market. [JEL classification: G13; G14;
G15]. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:67–86, 2003
The valuation of reset options with multiple strike resets and reset dates
Authors: Liao Szu‐Lang , Wang Chou‐Wen
Published: November 2002

This article makes two contributions to the literature. The first contribution is to provide the
closed‐form pricing formulas of reset options with strike resets and predecided reset dates. The exact
closed‐form pricing formulas of reset options with strike resets and continuous reset period are also
derived. The second contribution is the finding that the reset options not only have the phenomena of Delta jump
and Gamma jump across reset dates, but also have the properties of Delta waviness and Gamma waviness, especially
near the time before reset dates. Furthermore, Delta and Gamma can be negative when the stock price is near the
strike resets at times close to the reset dates. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark
23:87–107,2003
The behavior and performance of major types of futures traders
Authors: Wang Changyun
Published: November 2002

This article examines the behavior and performance of speculators and hedgers in 15 U.S. futures markets. We
find that after controlling for market risk factors, speculators are contrarians, but respond positively to market
sentiment. In contrast, hedgers engage in positive feedback trading and trade against market sentiment. We also
find that trades of speculators (hedgers) are positively (negatively) correlated with
subsequent abnormal returns; however, it does not appear that speculators possess superior forecasting power.
Therefore, hedging pressure effects likely explain the negative relation between the performance of speculators and
hedgers. The positive feedback trading by hedgers together with their negative performance suggests that hedgers
have a destabilizing impact on futures prices. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:1–31,
2003
Efficacy of transfection rates on head and neck squamous cell cancer by a novel adenovirus: An in vivo and in vitro study
Authors: Lalonde Elise S. , Beyer Gregory , Friedlander Paul L. , Kolls Jay K.
Published: December 2002

Introduction

Internalization of wild‐type adenovirus is dependent on binding to a coxsackie‐adenovirus receptor (CAR). Unfortunately, many tumors lack these receptors. We hypothesized that a novel RGD adenovirus, which binds by way of cellular integrins, would improve the transfection of head and neck cancers.

Materials and Methods

Three squamous cell cancer lines were transfected with either the wild type or the novel RGD containing a luciferase reporter gene. After 48 hours, the transfection rate was determined. This was correlated with CAR and αVβ3 and αVβ5 integrin expression as determined by flow cytometry. A similar experiment was performed in a nude mouse model to determine in vivo differences of transfection rate.

Results

Statistically significant increased rates of transfection were seen for the novel adenovirus at all multiplicities of infection (MOIs) in the CAL‐27 and SCC‐4 cell lines. Increased rates of transfection were seen at lower viral titers for the SCC‐25 cells. Flow cytometry revealed low CAR expression in all cell lines but no consistent pattern of integrin expression. The nude mouse model demonstrated a 43‐fold higher rate of transfection for the novel RGD adenovirus.

Conclusions

A modified RGD adenovirus increased the efficacy of transfection in specific cell lines and in the nude mouse model. It is possible that modified adenoviruses may improve gene delivery to patients with advanced or recurrent head and neck cancers. © 2002 Wiley Periodicals, Inc.
Association between smoking during radiotherapy and prognosis in head and neck cancer: A follow‐up study
Authors: Browman George P. , Mohide E. Ann , Willan Andrew , Hodson Ian , Wong Gene , Grimard Laval , MacKenzie Robert G. , El‐Sayed Samy , Dunn Edward , Farrell Sylvia
Published: December 2002

Background.

The study objective was to confirm a previous finding that patients with stage III/IV squamous head and neck cancer (SHNC) who smoke during radiotherapy (RT) experience reduced survival.

Methods.

An observational cohort study. Patients' smoking status was assessed weekly by questionnaire plus blood cotinine. Patients were assessed every 3 to 4 months for survival. Logistic regression and Cox proportional hazards analyses were used to detect the independent contribution of smoking on survival.

Results.

Of 148 patients, 113 smoked during RT. Blood cotinine and smoking questionnaire responses were highly correlated (Spearman R = .69; p < .0005). Abstainers and very light smokers experienced better survival than light, moderate, and heavy smokers (median, 42 vs 29 months; p = .07). Tumor and nodal status and years smoked were the most important prognostic factors. Smoking during RT was not an independent predictor of survival, but baseline smoking status was (p = .016).

Conclusion.

Smoking status should be documented in all future trials of RT in SHNC to allow for pooled analyses with sufficient power to address this question. © 2002 Wiley Periodicals, Inc. Head Neck 24: 1031–1037, 2002
Differential effects of happy, neutral, and sad still‐faces on 2‐, 4‐ and 6‐month‐old infants
Authors: Rochat Philippe , Striano Tricia , Blatt Lauren
Published: November 2002

The role of facial expression in the determination of infants' reaction to the sudden still‐face of a social partner was investigated. In a within subject design, 2, 4 and 6‐month‐old infants were tested in periods of normal interaction interspersed with periods of prolonged still‐face episodes in which the female adult social partner adopted either a happy, neutral, or sad static facial expression while maintaining eye contact with the infant. Proportion of infants' smiling and gazing at the social partner as indices of reaction from the various still‐face episodes reveal that, in comparison with same age control groups, four and six‐month‐old infants did not demonstrate any differential responses depending on either happy, neutral, and sad still‐faced expression. In contrast, two‐month olds demonstrated some evidence of a reduced still‐face effect in the happy still‐face condition. These results point to early developmental changes in the mechanisms underlying the still‐face phenomenon. We propose that by 4 months, and not prior, the reaction to still‐face episodes are essentially based on the detection of social contingencies. Copyright © 2002 John Wiley & Sons, Ltd.
Caring for infant daughters and sons in dual‐earner households: maternal reports of father involvement in weekday time and tasks
Authors: Manlove Elizabeth E. , Vernon‐Feagans Lynne
Published: November 2002

This study focused on maternal reports of gender differences in weekday father involvement with 12‐month‐olds in 47 dual‐earner households utilizing full time infant day care. Three involvement variables were considered: father's time alone with the infant; father's time available to the infant; and father participation in caregiving tasks. The results showed fathers to be available to sons significantly more than daughters. Fathers were also significantly more involved in caregiving tasks with sons than with daughters. There was no difference in father time alone with sons and daughters. Examination of these three involvement measures in relation to demographic, family environment, and infant temperament measures revealed that mothers' reported fathers as being available more to sons than to daughters. In addition, mothers reported fathers to be more available to temperamentally easy sons than to temperamentally difficult sons. Recommendations are made for future research. Copyright © 2002 John Wiley & Sons, Ltd.
Mediation in a sibling context: the relations of older siblings' mediating behaviour and younger siblings' task performance
Authors: Klein Pnina S. , Feldman Ruth , Zarur Shlomit
Published: November 2002

We investigated the sibling relationship as a context for cognitive development. Forty preschoolers (ages 5–6) and their younger siblings (ages 2–3) were visited at home. Four games were presented to the older siblings and they were asked (a) to estimate how well their younger sibling will perform on each game and (b) to teach the younger sibling how to use the games. The older siblings' mediating behaviours during the teaching session and the younger siblings' performance on the four tasks were coded. The frequency of mediating behaviours—including attention focusing, amplifying affect and providing meaning, fostering a sense of competence, regulating of the learning process, de‐contextualization, and negative feedback in the form of mocking and laughing at errors, predicted the younger siblings' task performance. The older sibling's accurate perception of the younger child's competence was uniquely predictive of task performance. The highest amount of mediation was observed in older‐brother–younger‐brother pairs, in particular the behaviours of negative feedback and amplifying affect. Results contribute to the discussion on the role of siblings as moderators of cognitive development and are discussed in terms of Vygotsky's cultural–historical perspective on apprenticeship. Copyright © 2002 John Wiley & Sons, Ltd.
Posture, muscular tone and visual attention in 5 month‐old infants
Authors: Lefèvre Carole
Published: November 2002

The present paper aims at studying the relationships between posture, muscle tone and visual attention in 5 month‐old infants. To this end, a specially designed seating arrangement made it possible to vary posture while keeping constant the spatial relationship between eyes and stimuli. Five month‐olds were placed in the reclining position (30°) or in a more erect position (60°). The more erect the posture, the more difficult it should be for the infant to maintain a straight body axis. Muscle tone was evaluated, and infants distinguished in terms of whether they were hypertonic or hypotonic. It was hypothesised that in a more erect position hypotonic children, who experience more difficulties in maintaining posture, should organise their visual exploration in ways different from those considered to be hypertonic. To test it, pairs of three‐dimensional stimuli were presented in the distal visual field for one group (N=48) and in the proximal visual field in another group (N=32) for 2 min in each posture.

The dynamical organisation of attention was evaluated through the number and duration of fixations on each target, the number of shifts from one target to the other (alternations) and the number of repetitions (back to the previous target). Results showed that visual behaviour was significantly affected by the distance at which stimuli were presented. Infants spent more time in visual exploration when the object was within reach than when it was out of reach. Although posture was shown to play a role in the organisation of visual exploration, no link with muscle tone was found, a surprising result which is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
The infant ‘motoric’ dream: where mothers' eye and scientist meet
Authors: Salzarulo Piero , Toselli Monica
Published: November 2002

One hundred twenty women were asked about their ideas on infants' dream. Two interviews were undertaken, before birth and 1 month after birth. The majority of women (both before and after birth) responded that infants dream. The reasons why they attributed dreaming to infants changed from before birth to after birth. At one month, these reasons were based on infant movements and behaviours, factors also taken into consideration by sleep researchers. Copyright © 2002 John Wiley & Sons, Ltd.
Evidence of chromosome regions and gene involvement in inflammatory breast cancer
Authors: Lerebours Florence , Bertheau Philippe , Bieche Ivan , Driouch Keltouma , de The Hugues , Hacene Kamel , Espie Marc , Marty Michel , Lidereau Rosette
Published: November 2002

Inflammatory breast cancer (IBC) is a rare but particularly aggressive form of primary breast cancer. In contrast to noninflammatory breast cancer (non IBC), the molecular alterations underlying IBC are poorly known. We postulated that the kind and frequency of these alterations might differ between IBC and non IBC and account for its particular aggressiveness. We investigated allelic losses associated with primary breast cancer (on chromosome arms 1p, 3p, 6p, 6q, 7q, 8p, 9p, 11p, 11q, 16q, 17p and 17q) by analyzing 71 microsatellite markers in 66 cases of IBC. Loss of heterozygosity (LOH) was frequent, with a mean fractional allelic loss (FAL) index of 52%. Relative to published data on non IBC, allelic loss was particularly frequent at 3p21‐p14, 6p, 8p22, 11q, 13q14 and 17q21, suggesting the presence of genes that are markedly altered in IBC. In contrast, the DNA amplification levels of ERBB2, MYC and CCND1, as measured by real‐time quantitative PCR, did not differ between IBC and non IBC. © 2002 Wiley‐Liss, Inc.