bluuebunny/crossref_metadata_2025 huggingface dataset:
Generalized sum‐free subsets
Authors: Caro Yair
Published: September 2002

Let F = {A(i) : 1 ≤ i ≤ t, t ≥ 2}, be a finite collection of finite, pairwise disjoint subsets of Z+. Let S ⊂ R\{0} and A ⊂ Z+ be finite sets. Denote by SA = {, Si ∈ S, the si are not necessarily distinct}. For S and F as above we say that S is F‐free if for every A(i), A(j) ∈ F, i ≠ j, SA(i) ⋂ SA(j) = ϕ.

We prove that for S and F as above, S contains an F‐free subset Q such that |Q| ≥ c(F)|S|, when c(F) is a positive constant depending only on F.

This result generalizes earlier results of Erdos [3] and Alon and Kleitman [2], on sum‐free subsets. Several possible extensions are also discussed.
Analysis of a model in solar magnetohydrostatics
Authors: Eberly David
Published: September 2002

The model for resistive diffusion of a force‐free magnetic field in a compressible plasma is analysed. Such a model has been suggested for describing the behavior of the solar outer atmosphere and that of solar flares. Previous analysis of the model involved assumptions of linear plasma velocity and constant magnetic energy. This paper deals with nonconstant magnetic energy in the cases of linear plasma velocity and planar plasma velocity. Some necessary conditions on the plasma direction vectors are derived. Finally, some aspects of the model assumptions are discussed, including nonnormality of initial data vectors to initial surfaces.
The effect of a single point on correlation and slope
Authors: Farnsworth David L.
Published: September 2002

By augmenting a bivariate data set with one point, the correlation coefficient and/or the slope of the regression line can be changed to any prescribed values. For the target value of the correlation coefficient or the slope, the coordinates of the new point are found as a function of certain statistics of the original data. The location of this new point with respect to the original data is investigated.
Banach‐Mackey spaces
Authors: Qiu Jing Hui , McKennon Kelly
Published: September 2002

In recent publications the concepts of fast completeness and local
barreledness have been shown to be related to the property of all weak‐* bounded
subsets of the dual (of a locally convex space) being strongly bounded. In this paper
we clarify those relationships, as well as giving several different characterizations
of this property.
Inner composition of analytic mappings on the unit disk
Authors: Gill John
Published: September 2002

A basic theorem of iteration theory (Henrici [6]) states that f analytic on
the interior of the closed unit disk D and continuous on D with Int(D)f(D) carries
any point z ϵ D to the unique fixed point α ϵ D of f. That is to say, fn(z) → α as
n → ∞. In [3] and [5] the author generalized this result in the following way:
Let Fn(z) : = f1∘…∘fn(z). Then fn → f uniformly on D implies Fn(z)λ, a
constant, for all z ϵ D. This kind of compositional structure is a generalization of
a limit periodic continued fraction. This paper focuses on the convergence behavior
of more general inner compositional structures f1∘…∘fn(z) where the fj′s are
analytic on Int(D) and continuous on D with Int(D)fj(D), but essentially random.
Applications include analytic functions defined by this process.
Best approximation in Orlicz spaces
Authors: Al-Minawi H. , Ayesh S.
Published: September 2002

Let X be a real Banach space and (Ω, μ) be a finite measure space and ϕ be a
strictly icreasing convex continuous function on [0, ∞) with ϕ(0) = 0. The space
Lϕ(μ, X) is the set of all measurable functions f with values in X such that for some c > 0. One of the main results of this paper is:
“For a closed subspace Y of X, Lϕ(μ, Y) is proximinal in Lϕ(μ, X) if and only if
L1(μ, Y) is proximinal in L1(μ, X) ′​′. As a result if Y is reflexive subspace of X,
then Lϕ(ϕ, Y)
is proximinal in Lϕ(μ, X). Other results on proximinality of subspaces
of Lϕ(μ, X) are proved.
Inverses of measures on a class of discrete groups
Authors: Karanikas C.
Published: September 2002

We examine a class of groups G, having a certain growth condition. We given an estimate for the norm of the inverse of an element in ll(G) in terms of the
spectral radius and the cardinality of the support.
Characterization of Hankel transformable generalized functions
Authors: Betancor J. J.
Published: September 2002

In this paper we prove a characterization theorem for the elements of the
space of generalized functions defined by A. H. Zemanian.
Some Bazilevič functions of order beta
Authors: Halim S. A.
Published: September 2002

Distortion theorems and coefficient estimates are obtained for a new class of Bazilevič functions.
Some Friedmann cosmological solutions in the scale covariant theory of gravitation
Authors: Beesham Aroonkumar
Published: September 2002

The scale covariant theory of gravity admits the possibility of a time varying
gravitational constant but contains a gauge function for which there is no independent equation.
The circumstances under which explicit forms for a gauge function may be derived within the
context of Friedmann‐Robertson‐Walker cosmological models are investigated and several forms
are derived.
Fuzzy θ‐closure operator on fuzzy topological spaces
Authors: Mukherjee M. N. , Sinha S. P.
Published: September 2002

The paper contains a study of fuzzy θ‐closure operator, θ‐closures of fuzzy sets in a
fuzzy topological space are characterized and some of their properties along with their relation with
fuzzy δ‐closures are investigated. As applications of these concepts, certain functions as well as
some spaces satisfying certain fuzzy separation axioms are characterized in terms of fuzzy θ‐closures
and δ‐closures.
Remarks on semiseparation of lattices
Authors: Vlad Carmen D.
Published: September 2002

This paper is concerned primarily with conditions for semiseparation and
separation of lattices. These conditions are expressed in terms of the general
Wallman space.
From paths to stars
Authors: Alameddine A. F.
Published: September 2002

The number of cycles in the complement T′ of a tree T is known to increase
with the diameter of the tree. A similar question is raised and settled for the number of
complete subgraphs in T′ for a special class of trees via Fibonacci numbers. A structural
characterization of extremal trees is also presented.
Boundary value problems for partial differential equations with piecewise contant delay
Authors: Wiener Joseph
Published: September 2002

The influence of certain discontinuous delays on the behavior
of solutions to some typical equations of mathematical physics is
studied.
Some results on the span of families of Banach valued independent, random variables
Authors: Hemasinha Rohan
Published: September 2002

Let E be a Banach space, and let (Ω, ℱ, P) be a probability space.
If L1(Ω) contains an isomorphic copy of L1[0, 1] then in (1 ≤ P < ∞), the closed
linear span of every sequence of independent, E valued mean zero random variables has
infinite codimension. If E is reflexive or B‐convex and 1 < P < ∞ then the closed
linear span of any family of independent, E valued, mean zero random
variables is super‐reflexive.
Measure characterizations and properties of normal and regular lattices
Authors: Grassi Peter M.
Published: September 2002

Various equivalent characterizations of normality are considered and a
measure theoretic definition is given for strongly normal lattices. Measure
conditions related to the apace of σ‐smooth, lattice‐regular, 0 − 1 measures are noted
which imply, or are equivalent to, the space being Hausdorff, regular, or prime
complete.
A double chain of coupled circuits in analogy with mechanical lattices
Authors: Boyd J. N. , Raychowdhury P. N.
Published: September 2002

A unitary transformation obtained from group theoretical considerations is applied to the problem of
finding the resonant frequencies of a system of coupled LC‐circuits. This transformation was previously derived to
separate the equations of motion for one dimensional mechanical lattices. Computations are performed in matrix
notation. The electrical system is an analog of a pair of coupled linear lattices. After the resonant frequencies have
been found, comparisons between the electrical and mechanical systems are noted.
On the Arens products and reflexive Banach algebras
Authors: Wong Pak-Ken
Published: September 2002

We give a characterization of reflexive Banach algebras involving the Arens product.
On a fixed point theorem of Pathak
Authors: Fisher Brian
Published: September 2002

It is shown that the continuity of the mapping in Pathak′s fixed point theorem for
normed spaces is not necessary.
Note on quasi‐bounded sets
Authors: Bosch Carlos , Kucera Jan , McKennon Kelly
Published: September 2002

It is shown that a union of two quasi‐bounded sets, as well as the closure of a
quasi‐bounded set, may not be quasi‐bounded.
An optimal control problem in economics
Authors: Highfill Jannett , McAsey Michael
Published: September 2002

The first problem in the economics of natural resources is to find the rate at
which to extract the resource in order to optimize its value when there are no extraction
costs. It is shown that the existence of an optimal extraction path is not guaranteed by a
utility function that is merely (strictly) concave, but that the additional requirement of
asymptotic nonlinearity will assure the existence of the desired optimum.
On weights which admit the reproducing kernel of Bergman type
Authors: Pasternak-Winiarski Zbigniew
Published: September 2002

In this paper we consider (1) the weights of integration for which the reproducing kernel of the Bergman type can be defined, i.e., the admissible weights, and (2) the kernels defined by such weights. It is verified that the weighted Bergman kernel has the analogous properties as the classical one. We prove several sufficient conditions and necessary and sufficient conditions for a weight to be an admissible weight. We give also an example of a weight which is not of this class. As a positive example we consider the weight μ(z) = (Imz)2 defined on the unit disk in ℂ.
On cat (X\p)
Authors: Perez Juan Julian Rivadeneyra
Published: September 2002

The Lusternik‐Schnirelmann category of a PL‐manifold does not increase if we delete a point of it. This is false in the CW‐complex category.

Corrigendum to
“On cat (X\p)”dx.doi.org/10.1155/S0161171292001066
Fourier transforms of Dini‐Lipschitz functions on Vilenkin groups
Authors: Younis M. S.
Published: September 2002

In [4] we proved some theorems on the Fourier Transforms of functions satisfying conditions related to the Dini‐Lipschitz conditions on the n‐dimensional Euclidean space Rn and the torus group Tn. In this paper we extend those theorems for functions with Fourier series on Vilenkin groups.
Common fixed points of maps on fuzzy metric spaces
Authors: Mishra S. N. , Sharma Nilima , Singh S. L.
Published: September 2002

Following Grabiec′s approach to fuzzy contraction principle, the purpose of this note is to obtain common fixed point theorems for asymptotically commuting maps on fuzzy metric spaces.
Fuzzy congruences on groups and rings
Authors: Samhan Marouf A. , Ahsanullah T. M. G.
Published: September 2002

We prove that the lattice of fuzzy congruences of a group G (resp. ring R) is isomorphic to the lattice of fuzzy normal subgroups of G (resp. fuzzy ideals of R).
A fully parallel method for tridiagonal eigenvalue problem
Authors: Li Kuiyuan
Published: September 2002

In this paper, a fully parallel method for finding all eigenvalues of a real matrix pencil (A, B) is given, where A and B are real symmetric tridiagonal and B is positive definite. The method is based on the homotopy continuation coupled with the strategy ?Divide‐Conquer? and Laguerre iterations. The numerical results obtained from implementation of this method on both single and multiprocessor computers are presented. It appears that our method is strongly competitive with other methods. The natural parallelism of our algorithm makes it an excellent candidate for a variety of advanced architectures.
Some characterizations of totients
Authors: Haukkanen Pentti
Published: September 2002

An arithmetical function is said to be a totient if it is the Dirichlet convolution between a completely multiplicative function and the inverse of a completely multiplicative function. Euler′s phi‐function is a famous example of a totient. All completely multiplicative functions are also totients. There is a large number of characterizations of completely multiplicative functions in the literature, while characterizations of totients have not been widely studied in the literature. In this paper we present several arithmetical identities serving as characterizations of totients. We also introduce a new concrete example of a totient.
On approximation of functions and their derivatives by quasi‐Hermite interpolation
Authors: Min G.
Published: September 2002

In this paper, we consider the simultaneous approximation of the derivatives of the
functions by the corresponding derivatives of quasi‐Hermite interpolation based on the zeros of (1 − x2)pn(x) (where pn(x)is a Legendre polynomial). The corresponding approximation degrees are given.
It is shown that this matrix of nodes is almost optimal.
Some results on boundary value problems for functional differential equations
Authors: Tsamatos P. Ch. , Ntouyas S. K.
Published: September 2002

Existence results for a second order boundary value problem for functional differential
equation, are givn. The results are based on the nonlinear Alternative, of Leray‐Schauder and rely
on a priori bounds on solutions. These results are generalizations of recent results from ordinary
differential equations and complete our earlier results on the same problem.
On oblique waves forcing by a porous cylindrical wall
Authors: Faltas M. S.
Published: September 2002

The problem of oblique cylindrical linearized wave motion is considered for a fluid
of infinite depth or finite constant depth in the presence of an impermeable cylindrical wall and coaxial
porous wall immersed vertically in the fluid. The motion is generated once by the oscillations, which are
periodic in time and in θ‐direction, of the impermeable wall and next by the porous wall. The velocity
potentials have been found in closed forms in the different regions of the fluid and then calculating the
hydrodynamic pressure distribution on the porous wall and the profile of the free surface. The scattering
problem of oblique waves is then considered. A wave trapping phenomenon is investigated. Numerical
results are given to the case of radial incident waves and the case when the angle of incident waves is 30°
to the radial direction.
Steady state temperatures in a quarter plane
Authors: Aggarwala B. D. , Nasim C.
Published: September 2002

The discontinuous boundary value problem of steady state temperatures in a
quarter plane gives rise to a pair of dual integral equations which are not of Titchmarch
type. These dual integral equations are considered in this paper.
On the approximate solution of nonlinear singular integral equations with positive index
Authors: Amer S. M.
Published: September 2002

This paper is devoted to investigating a class of nonlinear singular integral equations
with a positive index on a simple closed smooth Jordan curve by the collocation method. Sufficient
conditions are given for the convergence of this method in Holder space.
A remark on certain p‐valent functions
Authors: Aouf M. K. , Darwish H. E.
Published: September 2002

The object of the present paper is to prove an interesting result for
certain analytic and p‐valent functions in the unit disc U = {z : |z| < 1}.
On weak solutions of semilinear hyperbolic‐parabolic equations
Authors: Ferreira Jorge
Published: September 2002

In this paper we prove the existence and uniqueness of weak solutions of the mixed
problem for the nonlinear hyperbolic‐parabolic equation

urn:x-wiley:01611712:media:ijmm289648:ijmm289648-math-0001

with null Dirichlet boundary conditions and
zero initial data, where F(s) is a continuous function such
that sF(s) ≥ 0, ∀s ∈ R and {A(t); t ≥ 0} is a family of operators of .
For the
existence we apply the Faedo‐Galerkin method with
an unusual a priori estimate and a result of
W. A. Strauss. Uniqueness is proved only for some
particular classes of functions F.
A fixed point theorem for non‐self set‐valued mappings
Authors: Rhoades B. E.
Published: September 2002

Let X be a complete, metrically convex metric space, K a closed convex subset of X, CB(X) the set of closed and bounded subsets of X. Let F : K → CB(X) satisfying definition (1) below, with the added condition that Fx⫅K for each x ∈ ∂K. Then F has a fixed point in K. This result is an extension to multivalued mappings of a result of Ćirić [1].
The GL(n, Fp)—invariance of the Potts Hamiltonian
Authors: Caragiu Mihai , Caragiu Mellita
Published: September 2002

After defining a meanfield by arithmetic means, using multiplicative characters of finite
fields, its Potts Hamiltonian is exactly computed. Moreover, it proves to be invariant with respect to
every change of basis in Fq over the prime field Fp.
On X‐valued sequence spaces
Authors: Pehlivan S.
Published: September 2002

Certain spaces of X‐valued sequences are introduced and some of their properties are
investigated. Köthe‐ Toeplitz duals of these spaces are examined.
A note on connectedness in cartesian closed categories
Authors: Vainio Reino
Published: September 2002

Primaxily working in the category of limit spaces and continuous maps we suggest
a new concept of connectivity with application in all categories where function space objects
satisfy natural exponential laws. In a separate Appendix we motivate the development of
a homotopy theory for spaces of real‐valued continuous maps endowed with the structure of
continuous convergence.
Ordered compactifications and families of maps
Authors: Liu D. M. , Kent D. C.
Published: September 2002

For a T3.5‐ordered space, certain families of maps are designated as “defining families.“
For each such defining family we construct the smallest T2‐ordered compactification such that
each member of the family can be extended to the compactification space. Each defining family
also generates a quasi‐uniformity on the space whose bicompletion produces the same T2‐ordered
compactification.
Multistep methods for coupled second order integro‐differential equations: stability, convergence and error bounds
Authors: Jódar Lucas , Marera José Luis , Rubio Gregorio
Published: September 2002

In this paper multistep methods for systems of coupled second order Volterra integro‐differential
equations are proposed. Stability and convergence properties are studied and an error bound
for the discretization error is given.
Finite difference approximations for a class of non‐local parabolic equations
Authors: Lin Yanping , Xu Shuzhan , Yin Hong-Ming
Published: September 2002

In this paper we study finite difference procedures for a class of parabolic equations
with non‐local boundary condition. The semi‐implicit and fully implicit backward Euler schemes
are studied. It is proved that both schemes preserve the maximum principle and monotonicity of
the solution of the original equation, and fully‐implicit scheme also possesses strict monotonicity.
It is also proved that finite difference solutions approach to zero as t → ∞ exponentially. The
numerical results of some examples are presented, which support our theoretical justifications.
On an inverse to the Hölder inequality
Authors: Pečarić J. , Pearce C. E. M.
Published: September 2002

An extension is given for the inverse to Hölder′s inequality obtained recently
by Zhuang.
Convergence of composition sequences of bilinear and other transformations {fn}, fn → z
Authors: Gill John
Published: September 2002

This paper investigates convergence behavior of composition sequences
f1∘f2∘…∘fn(z) and fn∘fn−1∘…∘f1(z) where the fn′s are bilinear transformations and fn → z.
Additional results are provided for the case when the fn′s are more general functions.
Subclasses of univalent functions subordinate to convex functions
Authors: Kim Yong Chan , Jung Il Bong
Published: September 2002

In this paper, we define a new subclass ℳα(A, B) of univalent functions and investigate
several interesting characterization theorems involving a general class of starlike functions.
On the global solvability of a class of fourth‐order nonlinear boundary value problems
Authors: Elgindi M. B. M. , Guan Zhengyuan
Published: September 2002

This paper is concerned with the global solvability of a class of fourth‐order nonlinear
boundary value problems that govern the deformation of an elastic beam which is acted upon by axial
compression, lateral forces and is in contact with a semi‐infinite medium acting as a foundation For
certain ranges of the acting axial compression force, the solvability of the equations follows from the
coercivity of their linear parts. Beyond these ranges this coercivity is lost. It is shown here that the
coercivity which ensures the global solvability can be generated by the nonlinear parts of the equations for
a certain type of foundation.
New approach to asymptotic stability: time‐varying nonlinear systems
Authors: Grujić L. T.
Published: September 2002

The results of the paper concern a broad family of time‐varying nonlinear systems with
differentiable motions. The solutions are established in a form of the necessary and sufficient conditions
for: 1) uniform asymptotic stability of the zero state, 2) for an exact single construction of a system
Lyapunov function and 3) for an accurate single determination of the (uniform) asymptotic stability
domain. They permit arbitrary selection of a function p(⋅) from a defined functional family to
determine a Lyapunov function v(⋅), [v(⋅)], by solving v′(⋅) = −p(⋅) {or equivalently,
v′(⋅) = −p(⋅)[1 − v(⋅)]}, respectively. Illstrative examples are worked out.
The neutrix convolution product in Z′(m) and the exchange formula
Authors: Li C. K. , Koh E. L.
Published: September 2002

One of the problems in distribution theory is the lack of definition for convolutions and
products of distribution in general. In quantum theory and physics (see e.g. [1] and [2]), one finds that
some convolutions and products such as
are in use. In [3], a definition for product of distributions
and some results of products are given using a specific delta sequence δn(x) = Cmnmρ(n2r2) in an
m‐dimensional space. In this paper, we use the Fourier transform on D′(m) and the exchange formula to
define convolutions of ultradistributions in Z′(m) in terms of products of distributions in D′(m). We
prove a theorem which states that for arbitrary elements
and
in Z′(m), the neutrix convolution exists in Z′(m) if and only if the product f∘g
exists in D′(m). Some results of convolutions are
obtained by employing the neutrix calculus given by van der Corput [4].
The universal semilattice compactification of a semigroup
Authors: Vishki H. R. Ebrahimi , Pourabdollah M. A.
Published: September 2002

The universal abelian, band, and semilattice compactifications of
a semitopological semigroup are characterized in terms of three function algebras. Some relationships among these function algebras and some well‐known ones, from the universal compactification point of view, are also discussed.
Rings with many idempotents
Authors: Chen Huanyin
Published: September 2002

We introduce a new stable range condition and investigate the structures of rings with many idempotents. These are also generalizations of corresponding results of J. Stock and H. P. Yu.
Nonlinear functional integrodifferential equations in Hilbert space
Authors: Park J. Y. , Lee S. Y. , Lee M. J.
Published: September 2002

Let X be a Hilbert space and let Ω ⊂ Rn be a bounded domain with smooth boundary ∂Ω. We establish the existence and norm estimation of solutions for the parabolic partial functional integro‐differential equation in X by using the fundamental solution.
On the strongly damped wave equation and the heat equation with mixed boundary conditions
Authors: Neves Aloisio F.
Published: September 2002

We study two one‐dimensional equations: the strongly damped wave equation and the heat equation, both with mixed boundary conditions. We prove the existence of global strong solutions and the existence of compact global attractors for these equations in two different spaces.
Local existence result of the single dopant diffusion including cluster reactions of high order
Authors: Bader R. , Merz W.
Published: September 2002

We consider the pair diffusion process which includes cluster
reactions of high order. We are able to prove a local (in time)
existence result in arbitrary space dimensions. The model
includes a nonlinear system of reaction‐drift‐diffusion equations,
a nonlinear system of ordinary differential equations in Banach
spaces, and a nonlinear elliptic equation for the electrochemical
potential. The local existence result is based on the fixed point
theorem of Schauder.
Coercive solvability of the nonlocal boundary value problem for parabolic differential equations
Authors: Ashyralyev A. , Hanalyev A. , Sobolevskii P. E.
Published: September 2002

The nonlocal boundary value problem, v′(t) + Av(t) = f(t)(0 ≤ t ≤ 1), v(0) = v(λ) + μ(0 < λ ≤ 1), in an arbitrary Banach space E with the strongly positive operator A, is considered. The coercive stability estimates
in Hölder norms for the solution of this problem are proved. The exact
Schauder′s estimates in Hölder norms of solutions of the
boundary value problem on the range {0 ≤ t ≤ 1, xℝ n}
for 2m‐order multidimensional parabolic equations are obtaine.
On second‐order multivalued impulsive functional differential inclusions in Banach spaces
Authors: Benchohra M. , Henderson J. , Ntouyas S. K.
Published: September 2002

A fixed point theorem for condensing maps due to Martelli is used
to investigate the existence of solutions to second‐order
impulsive initial value problem for functional differential
inclusions in Banach spaces.
An inverse problem for evolution inclusions
Authors: Ton Bui An
Published: September 2002

An inverse problem, the determination of the shape and a
convective coefficient on a part of the boundary from partial
measurements of the solution, is studied using 2‐person optimal
control techniques.
Isolation and simplicity for the first eigenvalue of the p‐Laplacian with a nonlinear boundary condition
Authors: Martínez Sandra , Rossi Julio D.
Published: September 2002

We prove the simplicity and isolation of the first eigenvalue for the problem Δpu = |u|p−2u in a bounded smooth domain Ω ⊂ ℝN, with a nonlinear boundary condition given by |∇u|p−2∂u/∂v = λ|u|p−2u on the boundary of the domain.
Nonlinear ergodic theorems for a semitopological semigroup ofnon‐Lipschitzian mappings without convexity
Authors: Li G. , Kim J. K.
Published: September 2002

Let G be a semitopological semigroup, C a nonempty subset of a
real Hilbert space H, and ℑ = {Tt : t ∈ G} a representation of G as asymptotically nonexpansive type mappings of C into itself. Let L(x) = {z ∈ H : infs∈Gsupt∈G‖Tts x − z‖ = inft∈G‖Tt x − z‖} for each x ∈ C and L(ℑ) = ∩x∈C L(x). In this paper, we prove that is nonempty for each x ∈ C if and only if there exists a unique nonexpansive retraction P of C into L(ℑ) such that PTs = P for all s ∈ G and for every x ∈ C. Moreover, we prove the ergodic convergence theorem for a semitopological semigroup of non‐Lipschitzian mappings without convexity.
A‐properness and fixed point theorems for dissipative type maps
Authors: Lan K. Q. , Webb J. R. L.
Published: September 2002

We obtain new A‐properness results for demicontinuous, dissipative type mappings defined only on closed convex subsets of a Banach space X with uniformly convex dual and which satisfy a property called weakly inward. The method relies on a new property of the duality mapping in such spaces. New fixed point results are obtained by utilising a theory of fixed point index.
Picking Some News about the Retroviral Vector World from the 9th Symposium of the European Society of Gene Therapy
Authors: Bagnis Claude
Published: September 2002

The 9th symposium of the European Society of Gene Therapy (ESGT) organized by Murat Tuncer (President of the Meeting), Bernd Gansbacher (President of the ESGT), and Meral Ozguc (Secretary of the Meeting) took place in Antalya, South Turkey, on 2–4 November 2001. Although the international political context made difficult the coming of some researchers, this symposium has drawn an interesting picture of the works in progress in Europe and in the Mediterranean area.
A multiplicity result for a quasilinear gradient elliptic system
Authors: Ahammou Abdelaziz
Published: September 2002

The aim of this work is to establish the existence of infinitely
many solutions to gradient elliptic system problem, placing only
conditions on a potential function H, associated to the problem,
which is assumed to have an oscillatory behaviour at infinity. The
method used in this paper is a shooting technique combined with
an elementary variational argument. We are concerned with the
existence of upper and lower solutions in the sense of Hernández.
A new method for numerical solution of checkerboard fields
Authors: Berggren Stein A. , Lukkassen Dag , Meidell Annette , Simula Leon
Published: September 2002

We consider a generalized version of the standard checkerboard
and discuss the difficulties of finding the corresponding field
by standard numerical treatment. A new numerical method is
presented which converges independently of the local
conductivities.
Matrix variate Kummer‐Dirichlet distributions
Authors: Gupta Arjun K. , Cardeño Liliam , Nagar Daya K.
Published: September 2002

The multivariate Kummer‐Beta and multivariate Kummer‐Gamma
families of distributions have been proposed and studied recently
by Ng and Kotz. These distributions are extensions of Kummer‐Beta
and Kummer‐Gamma distributions. In this article we propose and
study matrix variate generalizations of multivariate Kummer‐Beta
and multivariate Kummer‐Gamma families of distributions.
Evaluating approximations to the optimal exercise boundary for American options
Authors: Mallier Roland
Published: September 2002

We consider series solutions for the location of the optimal exercise boundary of an American option close to expiry. By using Monte Carlo methods, we compute the expected value of an option if the holder uses the approximate location given by such a series as his exercise strategy, and compare this value to the actual value of the option. This gives an alternative method to evaluate approximations. We find the series solution for the call performs excellently under this criterion, even for large times, while the asymptotic approximation for the put is very good near to expiry but not so good further from expiry.
Laplace transforms and the American straddle
Authors: Alobaidi G. , Mallier R.
Published: September 2002

We address the pricing of American straddle options. We use
partial Laplace transform techniques due to Evans et al. (1950) to derive a pair of integral equations giving the locations of the optimal exercise boundaries for an American straddle option with a constant dividend yield.
Gauge independent Hamiltonian reduction of constrained systems
Authors: Muslih S. I.
Published: September 2002

A gauge independent method of obtaining the reduced space constrained dynamics is discussed in a purely Hamiltonian formalism. Three examples are studied.
Semigroup theory applied to options
Authors: Cruz-Báez D. I. , González-Rodríguez J. M.
Published: September 2002

Black and Scholes (1973) proved that under certain assumptions about the market place, the value of a European option, as a
function of the current value of the underlying asset and time, verifies a Cauchy problem. We give new conditions for the existence and uniqueness of the value of a European option by using semigroup theory. For this, we choose a suitable space that verifies some conditions, what allows us that the operator that appears in the Cauchy problem is the infinitesimal generator of a C0‐semigroup T(t). Then we are able to guarantee the existence and uniqueness of the value of a European option and we also achieve an explicit expression of that value.
The complexity of retina operators
Authors: Beauzamy Bernard
Published: September 2002

An artificial retina is a plane circuit, consisting of a matrix
of photocaptors; each has its own memory, consisting in a small
number of cells (3 to 5), arranged in parallel planes. The
treatment consists in logical operations between planes, plus
translations of any plane: they are called “elementary
operations” (EO). A retina operator (RO) is a transformation of
the image, defined by a specific representation of a Boolean
function of n variables (n is the number of neighboring cells
taken into account). What is the best way to represent an RO by
means of EO, considering the strong limitation of memory? For
most retina operators, the complexity (i.e., the number of EO
needed) is exponential, no matter what representation is used,
but, for specific classes, threshold functions and more generally
symmetric functions, we obtain a result several orders of
magnitude better than previously known ones. It uses a new
representation, called “Block Addition of Variables.” For
instance, the threshold function T 25,12 (find if at least 12
pixels are at 1 in a square of 5 × 5) required 62 403 599
EO to be performed. With our method, it requires only 38 084
operations, using three memory cells.
Serotonin Reuptake Inhibitor (Paxil) Does Not Prevent the Vasovagal Reaction Associated With Carotid Sinus Massage and/or Lower Body Negative Pressure in Healthy Volunteers
Authors: Takata Theodore S. , Wasmund Stephen L. , Smith Michael L. , Li Jian-Ming , Joglar Jose A. , Banks Kim , Kowal Robert C. , Page Richard L. , Hamdan Mohamed H.
Published: September 2002

Background—

The purpose of this study was to assess the effect of the serotonin reuptake inhibitor paroxetine hydrochloride (Paxil, SmithKline Beecham) on cardiovascular reflexes. We hypothesized that Paxil prevents neurally mediated syncope (NMS) by attenuating the sympathoinhibition and vagotonia associated with a vasovagal reaction.

Methods and Results—

In a double-blind randomized study, 25 healthy subjects with a positive response to either carotid sinus massage (CSM) or lower body negative pressure (LBNP) received Paxil (20 mg/d) or placebo for 6 weeks. Arterial baroreflex sensitivity (BRS), muscle sympathetic nerve activity (SNA), baroreflex control of SNA, blood pressure, and heart rate responses to CSM and LBNP were measured at baseline and at 6 weeks. Nineteen subjects completed the study (Paxil, n=9; placebo, n=10). In the Paxil group, BRS decreased significantly compared with baseline (15.8±4.0 ms/mm Hg versus 11.0±2.6 ms/mm Hg,
P
=0.05); however, all 9 subjects continued to have a positive response to LBNP with presyncope. Paxil did not attenuate the sympathoinhibition or vagotonia associated with a positive LBNP response and had no significant effect on baroreflex control of SNA. In the control group, no significant change in BRS was noted compared with baseline. Seven out of 9 subjects who had a positive LBNP response at baseline had a repeat positive LBNP response, and the subject with a positive CSM at baseline had a negative response at 6 weeks.

Conclusions—

Paxil decreases arterial BRS but does not prevent the presyncope associated with LBNP. The effect of Paxil on the autonomic reflexes in patients with neurally mediated syncope remains unclear.
Improving solid freeform fabrication by laser-based additive manufacturing
Authors: Hu D , Mei H , Kovacevic R
Published: September 2002

Solid freeform fabrication (SFF) methods for metal part building, such as three-dimensional laser cladding, are generally less stable and less repeatable than other rapid prototyping methods. A large number of parameters govern the three-dimensional laser cladding process. These parameters are sensitive to the environmental variations, and they also influence each other. This paper introduces the research work in Research Center for Advanced Manufacturing (RCAM) to improve the performance of its developed three-dimensional laser cladding process: laser-based additive manufacturing (LBAM). Metal powder delivery real-time sensing is studied to achieve a further controllable powder delivery that is the key technology to build a composite material or alloy with a functionally gradient distribution. An opto-electronic sensor is designed to sense the powder delivery rate in real time. The experimental results show that the sensor's output voltage has a good linear relationship with the powder delivery rate. A closed-loop control system is also built for heat input control in the LBAM process, based on infrared image sensing. A camera with a high frame rate (up to 800frame/s) is installed coaxially to the top of the laser—nozzle set-up. A full view of the infrared images of the molten pool can be acquired with a short nozzle—substrate distance in different scanning directions, eliminating the image noise from the metal powder. The closed-loop control results show a great improvement in the geometrical accuracy of the built feature.
Implementation of STEP Application Protocol 224 in an automated manufacturing planning system
Authors: Sharma R , Gao J X
Published: September 2002

This paper reports the results of an on-going research project at Cranfield University in collaboration with a leading consultant company. A major objective of the research to develop a new generation process planning system using the latest tools and technologies, and to fully comply with the international standard for the exchange of product model data (STEP) Application Protocol 224 (AP224) for process planning using machining features. Although AP224 has been accepted as an international standard, there is a surprising lack of compatible software packages in the market. The developed prototype STEP-enabled manufacturing planning system (SMPS) can generate process plans and associated documents from AP224 files automatically, without any user interaction. The system consists of decision logic stored in an external database that makes it generic and compatible with any manufacturing application. A graphical tool is provided for knowledge/logic capture. The system can also accept a feature tree generated using the feature model editor (FME), which has been developed as an add-on to the system. The FME is intended to be a tool for conceptual design of simple components. The FME feature tree is used in the early design stage while the AP224 file generated from the detailed design model is used in the later stages. The prototype system is intended for single-piece machined (prismatic) parts and has been tested with case studies provided by the project collaborators.
Engineering a new wrist joint replacement prosthesis—a multidisciplinary approach
Authors: Leonard L , Sirkett D M , Langdon I J , Mullineux G , Tilley D G , Keogh P S , Cunningham J L , Cole M O T , Prest P H , Giddins G E B , Miles A W
Published: September 2002

The wrist joint is highly complex and there remain unresolved problems to be overcome in designing a successful wrist joint prosthesis. Consequently, the results of total wrist joint replacements have been poor compared to those for hip and knee joint replacements. A multidisciplinary team of orthopaedic surgeons and engineers is working at Bath to tackle some of the key issues in the engineering of a new wrist joint prosthesis. Following a brief background to the work being undertaken by the group, this paper describes two ongoing research activities. Firstly, an assessment is being made of the optimum geometry for a wrist replacement through the use of a geometric constraint modeller. The second activity is the development of a mechanical simulator to assess wrist prosthesis function and loading. A computer algorithm controls articulation of the wrist using cables that mimic normal wrist tendons. This system allows for full movement of the hand and can also simulate external loading. The forces transmitted at the prosthesis/bone interfaces can be monitored using sensors attached adjacent to the prosthesis.
Determination of global design loads for large high-speed catamarans
Authors: Heggelund S E , Moan T , Oma S
Published: September 2002

Methods for calculation of design loads for high-speed vessels are investigated. The influence of operational restrictions on design loads is emphasized. Relevant operational criteria for high-speed displacement vessels are discussed. Procedures and criteria for numerical calculation of operational limits are incomplete and should be further investigated.

Operational limits and design loads for a 60 m catamaran are calculated on the basis of linear strip theory. Non-linear effects on design loads are assessed from calculations in regular waves. Simplified formulae commonly used by classification societies for prediction of operational limits seem to over-predict the reduction of motions and wave loads at reduced speed. When operational limits typically given by the shipmaster or the operator are used, the design loads found by direct calculations are comparable with design loads given by classification societies.

For vertical bending moment and torsion, the use of active foils is found to increase the linear loads. Owing to reduced motions, the foils reduce the non-linear loads and hence the total loads. The effect of non-linear horizontal loads is not investigated but can be important for transverse bending moment.
Homework assignments in couple and family therapy
Authors: Dattilio Frank M.
Published: September 2002

Homework has been cited as an integral part of a number of theoretical orientations and therapy formats; unfortunately, very little has been written about its use with couples and families. This is despite the fact that many couple and family therapists espouse the use of homework or out‐of‐session assignments in order to help the effects of therapy jell. This article reviews some of the empirical literature on homework assignments and their effectiveness in the domain of therapy for families and couples. It also highlights the effectiveness of and the need for out‐of‐session assignments in treatment. A case illustration is used to demonstrate how homework assignments may be used as a significant change agent in couple and family treatment. © 2002 Wiley Periodicals, Inc. J Clin Psychol/In Session 58: 535–547, 2002.
Multidrug resistance and behavioural phenotype of cancer cells
Authors: Bashir Imtiaz , Sikora Karol , Foster Christopher S.
Published: September 2002

Resistance to cytotoxic chemotherapy is a major obstacle preventing successful treatment of cancer, allowing dissemination of tumour metastases, and may be viewed as the ultimate cause of death in the majority of patients with a malignant disease. Although cytotoxic chemotherapy is classically employed to produce maximal killing of malignant cells, the therapeutic doses of individual drugs required to achieve this objective are, in general, highly toxic to non‐neoplastic host tissues. However, there are several different aspects of cancer cell biology, distinct from their susceptibility to cytotoxicity, that might be exploited in order to alter the behavioral phenotypes of malignant neoplasms. Such features include regulation of cell proliferation, tumorigenicity and metastatic potential Non‐cytotoxic modulation of malignant cells may provide an alternative, and more effective, method of controlling the aggressive behaviour of cancer cells while exhibiting less iatrogenic morbidity and mortality than the therapeutic regimens presently employed.
The influence of maternal nicotine exposure on neonatal lung alveolar epithelial status: an electron microscope study.
Authors: Maritz G. S. , Scott L. , Thomas R‐A.
Published: September 2002

The aim of the present study was to investigate the effect of maternal nicotine exposure (1 mg nicotine/kg body mass/day) on neonatal lung alveolar epithelial cells. Rats (Wistar descendants) were used. The data illustrate that maternal nicotine exposure during pregnancy and lactation resulted in alveolar fenestrations, blebbing and rupturing of the blood‐air barrier. The type I pneumocyte appears to be more sensitive to the effect of nicotine than the type II pneumocytes.
Adhesion characteristics of chondrocytes cultured separately and in co‐cultures with synovial fibroblasts.
Authors: Nevo Zvi , Silver Jonathan , Chorev Yochanan , Riklis Irena , Robinson Dror , Yosipovitch Zvi
Published: September 2002

The present study was designed to investigate the adherence mechanism(s) and behaviour of cultured chondrocytes under various culturing conditions, co‐culturing with fibroblasts, or growth in the presence of conditioned medium either of fibroblasts or chondrocytes. The findings obtained indicate that chondrocyte time‐adhesion curves and the final percentiles of attached cells to a plastic substrate are much slower and lower respectively than those of anchorage dependent cell types. The poorest adhesion occurs employing chondrocytes originated from suspension cultures, as compared to chondrocytes grown in monolayers. No interference with chondrocyte adhesion was found by inhibiting the production of proteoglycan (PG). Puromycin and to a lesser degree actinomycin but not cytosine arabinoside interfered with chondrocyte adhesion, suggesting the importance of protein synthesis in this process.

The nature of proadhesion modifying molecules in synoviocytes conditioned media and antiadhesive agents in chondrocyte conditioned media suggests that both substances are heat labile, non‐dialyzable, protein containing factors.
Apoptosis or programmed cell death?
Authors: Bowen Ivor D.
Published: September 2002

Although there are different ways in which cells may die, it is now thought that in a developmental context cells are induced to positively commit suicide whilst in a homeostatic context the absence of certain survival factors may provide the impetus for suicide. There appears to be some variation in the morphology and indeed the biochemistry of these suicide pathways; some treading the path of "apoptosis", others following a more generalized pathway to deletion, but both usually being genetically and synthetically motivated. There is some evidence that certain symptoms of "apoptosis" such as endonuclease activation can be spuriously induced without engaging a genetic cascade, however, presumably true apoptosis and programmed cell death must be genetically mediated. It is also becoming clear that mitosis and apoptosis are toggled or linked in some way and that the balance achieved depends on signals received from appropriate growth or survival factors.
Transforming growth factor(TGF)‐β1 induces leukemic cell‐growth‐promoting activity in fibroblast cells.
Authors: Komatsu K. , Nakamura H. , Akedo H.
Published: September 2002

The production of the leukemic cell‐growth‐promoting factor (LGF) in TGF‐β1‐treated fibroblast cells was studied. BALB/c3T3 mouse fibroblast(3T3) cells cultured in Eagle's medium containing a low concentration of TGF‐β1 (0.04‐1 ng/ml) secreted 3‐5 times more LGF than the cells cultured in the absence of TGF‐β1. The amount of LGF secretion was dose‐dependent on the concentration of post‐cultured medium and time‐dependent after the addition of TGF‐β1. Similar findings were obtained in human diploid fibroblasts, WI‐38 cells. LGF is a 18KD glycoprotein that is acid‐stable but heat‐unstable.
Is actin involved in the nuclear division in Amoeba proteus?
Authors: Pomorski Pawel , Grebecka Lucyna
Published: September 2002

During semi‐open mitosis of Amoeba proteus the nuclear envelope is not dispersed and nucleus divides by fission. The presence of actin layer close to nuclear envelope was demonstrated in interphase and telophase nuclei of that amoeba stained with rhodamine labelled phalloidin. In telophase, an accumulation of actin arises in the space between the future daughter nuclei. It appears to be comparable with the contractile ring of dividing cells. This suggests that actin associated with the nuclear envelope of Amoeba proteus may be involved in final separation of the daughter nuclei, forming a constriction ring at the middle of dividing nucleus.