bluuebunny/crossref_metadata_2025 huggingface dataset:
A MAYER-VIETORIS THEOREM FOR THE KAUFFMAN BRACKET SKEIN MODULE
Authors: LOFARO WALTER F.
Published: April 2003

The nth relative Kauffman bracket skein modules are defined and two theorems are given relating them to the Kauffman bracket skein module of a 3-manifold. The first theorem covers the case when the 3-manifold is split along a separating closed orientable surface and the second theorem addresses the case when the surface is nonseparating.
TURNING DOUBLE-TORUS LINKS INSIDE OUT
Authors: NORWOOD RICK
Published: April 2003

The notation of t/i numbers is used to described knots and links on the double torus in two different ways, as a step toward the eventual classification of double-torus links.
THE BRAID INDEX AND THE GROWTH OF VASSILIEV INVARIANTS
Authors: Stoimenow A.
Published: April 2003

We use the new approach of braiding sequences to prove exponential upper bounds for the number of Vassiliev invariants on knots with bounded braid index, bounded bridge number and arborescent knots.

We prove, that any Vassiliev invariant of degree k is determined by its values on knots with braid index at most k + 1.
λ-unknotting-number-one knots need not be prime
Authors: ASKITAS N.
Published: April 2003

We show that for certain unknotting operations λ their unknotting number uλ is not additive with respect to connected sums. In general the unknotting number of the connected sum of two knots is smaller than or equal to the sum of the unknotting numbers of the summands; we provide examples where the inequality is strict.
SKEIN RELATIONS FOR THE LINK INVARIANTS COMING FROM EXCEPTIONAL LIE ALGEBRAS
Authors: BERGER ANNA-BARBARA , STASSEN INES
Published: April 2003

Pulling back the weight systems associated with the exceptional Lie algebras and their standard representations by a modification of the universal Vassiliev-Kontsevich invariant yields link invariants; extending them to coloured 3-nets, we derive for each of them a skein relation.
BOUNDARY STRING LINKS
Authors: DE CAMPOS JOSÉ EDUARDO PRADO PIRES
Published: April 2003

The group BSL(k) of boundary cobordism classes of boundary k-string links is defined. An epimorphism from BSL(k) to a group of cobordism classes of matrices is defined. An action of a certain group of pure braids on BSL(k) provides all possible splittings for a given boundary k-link. A necessary and sufficient condition is given for two elements of BSL(k) to have the same closure as an F(k)-link (i.e., a boundary k-link with one of its splittings), up to F(k)-cobordism.
GENUS ONE, THREE-BRIDGE KNOTS ARE PRETZEL
Authors: FUKUHAMA SATOSHI , OZAWA MAKOTO , TERAGAITO MASAKAZU
Published: April 2003

We prove that genus one, three-bridge knots are pretzel knots.
LINKS WITH UNLINKING NUMBER ONE AND CONWAY POLYNOMIALS
Authors: HONGLER CAM VAN QUACH
Published: April 2003

Contrary to the case of knots, the property that a link has an unlinking number one is reflected in its Conway polynomial. Examples of the determination of the unlinking number are given.
UNKNOTTING OPERATIONS BY USING ORIENTED TRIVIAL TANGLE DIAGRAMS
Authors: NAGURA MAKI
Published: April 2003

Our main theorem is that the local move between any non equivalent oriented trivial tangle diagrams is an unknotting operation.
TANGLE DECOMPOSITIONS OF DOUBLE TORUS KNOTS AND LINKS
Authors: OZAWA MAKOTO
Published: April 2003

We characterize composite double torus knots and links, 2-string composite double torus knots.
GAUSS WORDS OF CURVES ON A TORUS
Authors: TANIO HITOE
Published: April 2003

In 1993, Cairns and Elton gave a condition for an abstract Gauss word to be realized as the Gauss word of a planar curve. In this paper, we extend their result to curves on surfaces of higher genus. In particular, we give a solution in the case of torus T2.
SOLUTIONS OF THE YANG-BAXTER EQUATION AND QUANTUM $\mathfrak{sl} (2)$
Authors: VYBORNOV MAXIM
Published: April 2003

We construct a quantum deformation of a family of the Yang-Baxter equation solutions naturally arising from a Lie algebra [Formula: see text].
INFORMATION SHARING GAMES
Authors: SLIKKER MARCO , NORDE HENK , TIJS STEF
Published: April 2003

In this paper we study information sharing situations. For every information sharing situation we construct an associated cooperative game, which we call an information sharing game. We show that the class of information sharing games coincides with the class of cooperative games with a population monotonic allocation scheme.
ON THE EVOLUTIONARY STABILITY OF "TOUGH" BARGAINING BEHAVIOR
Authors: POULSEN ANDERS
Published: April 2003

This paper investigates whether "tough" bargaining behavior, which gives rise to inefficiency, can be evolutionarily stable. We show that in a two-stage Nash Demand Game such behavior survives. Indeed, almost all the surplus may be wasted. We also study the Ultimatum Game. Here evolutionary selection wipes out all tough behavior, as long as the Proposer does not directly observe the Responder's commitment to rejecting low offers.
A VERTICALLY DIFFERENTIATED DUOPOLY WITH MARGINAL COST DIFFERENTIALS
Authors: SCHMITT PAMELA M.
Published: April 2003

A vertically differentiated duopoly model analyzes the impact of marginal cost differentials on price and quality. Firms play a two-stage game, first simultaneously choosing quality and then simultaneously choosing price. When the firm producing the high quality good faces an increase in its marginal cost, both firms increase price and upgrade quality. When the firm producing the low quality good faces an increase in its marginal cost, both firms decrease price and downgrade quality. When a first firm enters the market, quality position decisions are examined under the assumption that both the firm-specific and the quality-specific marginal costs are higher when a firm produces a higher quality good. The results show that the first entrant produces the low quality good and earns higher profits.
FLUCTUATIONS, NOISE AND SCALING IN THE CARDIO-PULMONARY SYSTEM
Authors: SUKI BÉLA , ALENCAR ADRIANO M. , FREY URS , IVANOV PLAMEN CH. , BULDYREV SERGEY V. , MAJUMDAR ARNAB , EUGENE STANLEY H. , DAWSON CHRISTOPHER A. , KRENZ GARY S. , MISHIMA MICHIAKI
Published: April 2003

The structure and the functioning of cardio-pulmonary system is complex and statistical physics appear to be suitable for their characterization. In this review, we examine scaling in cardio-pulmonary physiology. The focus will be on the interpretation of scaling behaviors and their relation to structure-function in the normal and diseased cardio-pulmonary system. First, we overview fluctuations and scaling in respiratory rate variability in terms of a neural network model. Next, we analyze fluctuations in human heartbeat dynamics under healthy and pathologic conditions using wavelets and multifractal approaches. We then discuss avalanche behavior of airway openings as well as scaling behavior of crackling sound generated during the process of airway openings. We also examine the relationship between the observed scaling properties and the design features of the pulmonary vascular tree. Finally, we show how the network failure of lung tissue structure leads to emphysema, a leading cause of respiratory disability and death worldwide.
Dual integral equations—revisited
Authors: Banerjea Sudeshna , Kar C. C.
Published: April 2003

Dual integral equations with trigonometric kernel are
reinvestigated here for a solution. The behaviour of one of the
integrals at the end points of the interval complementary to the
one in which it is defined plays the key role in determining the
solution of the dual integral equations. The solution of the dual
integral equations is then applied to find an exact solution of
the water wave scattering problems.
Seven‐dimensional considerations of Einstein′s connection. III. The seven‐dimensional Einstein′s connection
Authors: Kim Mi Ae , So Keum Sook , Cho Chung Hyun , Chung Kyung Tae
Published: April 2003

The purpose of the present paper is to prove a necessary and
sufficient condition for a unique Einstein′s connection to exist in
7‐g‐UFT and to display a surveyable tensorial representation of
seven‐dimensional Einstein′s connection in terms of the unified field
tensor, employing the powerful recurrence relations of the third kind obtained in earlier papers. All considerations in this paper are restricted to the first and second classes of X7, since the case of the third class, the simplest case, was already studied by many authors.
A construction of some ideals in affine vertex algebras
Authors: AdamoviĆ Dražen
Published: April 2003

We study ideals generated by singular vectors in vertex operator
algebras associated with representations of affine Lie algebras of types A and C. We find new explicit formulas for singular vectors in these vertex operator algebras at integer and half‐integer levels. These formulas generalize the expressions for singular vectors from Adamović (1994). As a consequence, we obtain a new family of vertex operator algebras for which we
identify the associated Zhu′s algebras. A connection with the
representation theory of Weyl algebras is also discussed.
On a criterion of Yakubovich type for the absolute stability of nonautonomous control processes
Authors: Fabbri R. , Impram S. T. , Johnson R.
Published: April 2003

We generalize a criterion of Yakubovich for the absolute
stability of control processes with periodic coefficients to the
case when the coefficients are bounded and uniformly continuous
functions.
Complexity of terms, composition, and hypersubstitution
Authors: Denecke Klaus , Wismath Shelly L.
Published: April 2003

We consider four useful measures of the complexity of a term: the maximum depth (usually called the depth), the minimum depth, the
variable count, and the operation count. For each of these, we produce a formula for the complexity of the composition in terms of the complexity
of the inputs s, t1, …, tn. As a corollary, we also obtain formulas for the complexity of
in terms of the complexity of t when t is a compound term and σ is a hypersubstitution. We then apply these formulas to the theory of M‐solid varieties, examining the k‐normalization chains of a variety with respect to the four complexity measures.
Mapping properties for convolutions involving hypergeometricfunctions
Authors: Kim J. A , Shon K. H.
Published: April 2003

For μ ≥ 0, we consider a linear operator Lμ : A → A defined by the convolution fμ∗f,
where . Let φ∗(A, B) denote the class of normalized functions f which are analytic in the open unit disk and satisfy the condition zf′/f≺(1 + Az)/1 + Bz,
−1 ≤ A < B ≤ 1, and let Rη(β) denote the class of
normalized analytic functions f for which there exits a number
η ∈ (−π/2, π/2) such that
Re(eiη(f′(z) − β)) > 0, (β < 1). The main object of
this paper is to establish the connection between
Rη(β) and φ∗(A, B) involving the operator
Lμ(f). Furthermore, we treat the convolution
for f ∈ Rη(β).
Bergman spaces of temperature functions on a cylinder
Authors: López-García Marcos
Published: April 2003

We define the weighted Bergman space consisting of temperature functions on the cylinder ST = S1 × (0, T) and belonging to Lp(ΩT, tβdxdt), where ΩT = (0, 2) × (0, T). For β > −1 we construct a family of bounded projections of Lp(ΩT, tβdxdt) onto . We use this to get, for 1 < p < ∞ and 1/p + 1/p′ = 1, a duality , where β′ depends on p and
β.
Common periodic points for a class of continuous commuting mappings on an interval
Authors: Kang Shin Min , Wang Weili
Published: April 2003

The existence of common periodic points for a family of continuous
commuting self‐mappings on an interval is proved and two
illustrative examples are given in support of our theorem and
definition.
Time estimates for the Cauchy problem for a third‐order hyperbolic equation
Authors: Varlamov Vladimir
Published: April 2003

A classical solution is considered for the Cauchy problem:
, x ∈ ℝ3, t > 0; u(x, 0) = f0(x), ut(x, 0) = f1(x), and
utt(x) = f2(x), x ∈ ℝ3, where α = const,
0 < α < 1. The above equation governs the propagation of
time‐dependent acoustic waves in a relaxing medium. A classical
solution of this problem is obtained in the form of convolutions
of the right‐hand side and the initial data with the fundamental
solution of the equation. Sharp time estimates are deduced for
the solution in question which show polynomial growth for small
times and exponential decay for large time when f = 0. They also
show the time evolution of the solution when f ≠ 0.
Asymptotic expansions and positivity of coefficients for largepowers of analytic functions
Authors: De Angelis Valerio
Published: April 2003

We derive an asymptotic expansion as n → ∞ for a large range of coefficients of (f(z)) n, where f(z) is a power series satisfying |f(z)| < f(|z|) for z ∈ ℂ,
z ∉ ℝ+. When f is a polynomial and the two
smallest and the two largest exponents appearing in f are
consecutive integers, we use the expansion to generalize results
of Odlyzko and Richmond (1985) on log concavity of polynomials,
and we prove that a power of f has only positive coefficients.
Wavelet analysis on a Boehmian space
Authors: Roopkumar R.
Published: April 2003

We extend the wavelet transform to the space of periodic
Boehmians and discuss some of its properties.
On sequentially retractive inductive limits
Authors: García Armando
Published: April 2003

Every locally complete inductive limit of sequentially complete
locally convex spaces, which satisfies Retakh′s condition (M)
is regular, sequentially complete and sequentially retractive. A
quasiconverse for this theorem and a criterion for sequential
retractivity of inductive limits of webbed spaces are given.
A more generalized Gronwall‐like integral inequality with applications
Authors: Ma Qinghua , Debnath Lokenath
Published: April 2003

This paper deals with a new Gronwall‐like integral inequality
which is a generalization of integral inequalities proved by Engler (1989) and Pachpatte (1992). The new Gronwall‐like integral inequality can be used in various problems in the theory of certain class of ordinary and integral equations.
On the special solutions of an equation in a finite field
Authors: Hailong Li , Wenpeng Zhang
Published: April 2003

The main purpose of this paper is to prove the following
conclusion: let p be a prime large enough and let k be a fixed positive integer with 2k|p − 1. Then for any finite field Fp and any element 0 ≠ c ∈ Fp, there exist three generators x, y, and z ∈ Fp such that xkyk + ykzk + xkzk = c.
Invariant manifold of hyperbolic‐elliptic type for nonlinear waveequation
Authors: Yuan Xiaoping
Published: April 2003

It is shown that there are plenty of hyperbolic‐elliptic
invariant tori, thus quasiperiodic solutions for a class of nonlinear wave equations.
Fatou maps in ℙn dynamics
Authors: Robertson John W.
Published: April 2003

We study the dynamics of a holomorphic self‐map f of complex
projective space of degree d > 1 by utilizing the notion of a
Fatou map, introduced originally by Ueda (1997) and independently
by the author (2000). A Fatou map is intuitively like an analytic
subvariety on which the dynamics of f are a normal family (such as a local stable manifold of a hyperbolic periodic point). We show that global stable manifolds of hyperbolic fixed points are given by Fatou maps. We further show that they are necessarily Kobayashi hyperbolic and are always ramified by f (and therefore any hyperbolic periodic point attracts a point of the
critical set of f). We also show that Fatou components are
hyperbolically embedded in ℙn and that a Fatou component which is attracted to a taut subset of itself is
necessarily taut.
On certain means of two arguments and their extensions
Authors: Neuman Edward , Sándor József
Published: April 2003

Inequalities for three means introduced by H.‐J. Seiffert are
obtained. Generalizations of these means, their basic properties, and inequalities satisfied by the new class of means are also included.
Closed orbits of (G, τ)‐extension of ergodic toral automorphisms
Authors: Noorani Mohd. Salmi Md.
Published: April 2003

Let A : T → T be an ergodic automorphism of a finite‐dimensional torus T. Also, let G be the set of elements in T
with some fixed finite order. Then, G acts on the right of T,
and by denoting the restriction of A to G by τ, we have A(xg) = A(x)τ(g) for all x ∈ T and g ∈ G. Now, let
be the (ergodic)
automorphism induced by the G‐action on T. Let
be an ‐closed orbit (i.e., periodic orbit) and τ
an A‐closed orbit which is a lift of . Then, the
degree of τ over is defined by the integer
,
where λ( ) denotes the (least) period of the respective
closed orbits. Suppose that τ1, …, τt is the distinct
A‐closed orbits that covers . Then,
. Now, let
. Then, the previous equation
implies that the t‐tuple is a partition of the
integer |G| (after reordering if needed). In this case, we say
that induces the partition of the
integer |G|. Our aim in this paper is to characterize this
partition for which
induces the partition is nonempty and
provides an asymptotic formula involving the closed orbits in such
a set as their period goes to infinity.
Cauchy approximation for sums of independent random variables
Authors: Neammanee K.
Published: April 2003

We use Stein′s method to find a bound for Cauchy approximation.
The random variables which are considered need to be independent.
Fixed‐point theorems for multivalued non‐expansive mappings without uniform convexity
Authors: Benavides T. Domínguez , Ramírez P. Lorenzo
Published: April 2003

Let X be a Banach space whose characteristic of noncompact convexity
is less than 1 and satisfies the nonstrict Opial condition. Let C be a bounded closed convex subset of X, KC(C) the family of all
compact convex subsets of C, and T a nonexpansive mapping from C into KC(C). We prove that T has a fixed point. The nonstrict Opial condition can be removed if, in addition, T is a 1‐χ‐contractive mapping.
Topological structure of solution sets of differential inclusions: the constrained case
Authors: Kryszewski Wojciech
Published: April 2003

We survey and announce some current results on the existence, the viability, and the topological structure of the viable solutions of differential equations and inclusion in Banach spaces under set constraints. Some new results concerning semilinear differential inclusions with state variables constrained to the so‐called regular and strictly regular sets, together with their applications, are presented and discussed.
Local solvability of a constrainedgradient system of total variation
Authors: Chidume C. E. , Zegeye H.
Published: April 2003

Suppose X is a real q‐uniformly smooth Banach space and F, K : X → X with D(K) = F(X) = X are accretive maps. Under various continuity assumptions on F and K such that 0 = u + KFu has a solution, iterative methods which converge strongly to
such a solution are constructed. No invertibility assumption is
imposed on K and the operators K and F need not be defined on compact subsets of X. Our method of proof is of independent interest.
Local uniform linear convexity with respect to the Kobayashi distance
Authors: Budzyńska Monika
Published: April 2003

We introduce the notion of local uniform linear convexity of bounded convex domains with respect to their Kobayashi distances.
Current and Future Gene Therapy for Malignant Gliomas
Authors: Kanzawa Takao , Ito Hideaki , Kondo Yasuko , Kondo Seiji
Published: April 2003

Malignant gliomas are the most common neoplasm in the central
nervous system. When treated with conventional treatments
including surgery, irradiation, and chemotherapy, the average
life expectancy of the most malignant type, glioblastoma
multiforme is usually less than 1 year. Therefore, gene therapy
is expected to be an effective and possibly curative treatment.
Many gene therapeutic approaches have demonstrated efficacy in
experimental animal models. However, the current clinical trials
are disappointing. This review focuses on current therapeutic
genes/vectors/delivery systems/targeting strategies in order to
introduce updated trends and hopefully indicate prospective gene
therapy for malignant gliomas.
Gene Therapy for Pediatric Cancer: State of the Art and Future Perspectives
Authors: Biagi Ettore , Bollard Catherine , Rousseau Raphael , Brenner Malcolm
Published: April 2003

While modern treatments have led to a dramatic improvement in
survival for pediatric malignancy, toxicities are high and a
significant proportion of patients remain resistant. Gene
transfer offers the prospect of highly specific therapies for
childhood cancer. “Corrective” genes may be transferred to
overcome the genetic abnormalities present in the precancerous
cell. Alternatively, genes can be introduced to render the
malignant cell sensitive to therapeutic drugs. The tumor can also
be attacked by decreasing its blood supply with genes that
inhibit vascular growth. Another possible approach is to modify
normal tissues with genes that make them more resistant to
conventional drugs and/or radiation, thereby increasing the
therapeutic index. Finally, it may be possible to attack the
tumor indirectly by using genes that modify the behavior of the
immune system, either by making the tumor more immunogenic, or by
rendering host effector cells more efficient. Several gene
therapy applications have already been reported for pediatric
cancer patients in preliminary Phase 1 studies. Although no major
clinical success has yet been achieved, improvements in gene
delivery technologies and a better understanding of mechanisms of
tumor progression and immune escape have opened new perspectives
for the cure of pediatric cancer by combining gene therapy with
standard therapeutic available treatments.
EMEA and Gene Therapy Medicinal Products Development in the European Union
Authors: Papaluca Amati Marisa , Pignatti Francesco , Nolte Alexis , Amerasinghe Nirosha , Gustafsson Daniel , Moulon Isabelle , Le Courtois Patrick
Published: April 2003

The evaluation of quality, safety, and efficacy of medicinal
products by the European Medicines Evaluation Agency (EMEA) via
the centralized procedure is the only available regulatory
procedure for obtaining marketing authorization for gene therapy
(GT) medicinal products in the European Union. The
responsibility for the authorization of clinical trials remains
with the national competent authorities (NCA) acting in a
harmonized framework from the scientific viewpoint. With the
entry into force of a new directive on good clinical practice
implementation in clinical trials as of 1 May 2004, procedural
aspects will also be harmonized at EU level. Scientifically sound
development of medicinal products is the key for the successful
registration of dossiers and for contributing to the promotion
and protection of public health. The objective of this paper is
to introduce the EMEA regulatory processes and scientific
activities relevant to GT medicinal products.
Retroviral Vector Biosafety: Lessons from Sheep
Authors: Van den Broeke Anne , Burny Arsène
Published: April 2003

The safety of retroviral‐based systems and the possible
transmission of replication‐competent virus to patients is a
major concern associated with using retroviral vectors for gene
therapy. While much effort has been put into the design of safe
retroviral production methods and effective in vitro monitoring
assays, there is little data evaluating the risks resulting from
retroviral vector instability at post‐transduction stages
especially following in vivo gene delivery. Here, we briefly
describe and discuss our observations in an in vivo experimental
model based on the inoculation of retroviral vector‐transduced
tumor cells in sheep. Our data indicates that the in vivo
generation of mosaic viruses is a dynamic process and that virus
variants, generated by retroviral vector‐mediated recombination,
may be stored and persist in infected individuals prior to
selection at the level of replication. Recombination may not only
restore essential viral functions or provide selective advantages
in a changing environment but also reestablish or enhance the
pathogenic potential of the particular virus undergoing
recombination. These observations in sheep break new ground in
our understanding of how retroviral vectors may have an impact on
the course of a preestablished disease or reactivate dormant or
endogenous viruses. The in vivo aspects of vector stability raise
important biosafety issues for the future development of safe
retroviral vector‐based gene therapy.
Taking Gene Therapy into the Clinic
Authors: Palmer Daniel H. , Chen Ming-Jen , Kerr David J.
Published: April 2003

Gene therapy represents a promising novel treatment strategy for
colorectal cancer. Preclinical data has been encouraging and
several clinical trials are underway. Many phase 1 trials have
proven the safety of the reagents but have yet to demonstrate
significant therapeutic benefit. Ongoing efforts are being made
to improve the efficiency of gene delivery and accuracy of gene
targeting with the aim of enhancing antitumor potency. It is
envisaged that gene therapy will be used in combination with other
therapies including surgery, chemotherapy, and radiotherapy to
facilitate the improvements in cancer treatments in the future.
The dynamics of Cosserat nets
Authors: Gratus J. , Tucker R. W.
Published: April 2003

A formulation of the dynamics of a collection of connected
simple 1‐dimensional Cosserat continua and rigid bodies is presented in terms of sections of an SO(3) fibration over a 1‐dimensional net. A large class of junction conditions is considered in a unified framework. All the equations of motion
and junction conditions are derived as extrema of a constrained variational principle on the net and are analysed perturbatively for structures with Kirchhoff constitutive properties. The whole discussion is based on the notion of a Cosserat net and its contractions obtained by taking certain limits that transform Cosserat elements to rigid structures. Generalisations are
briefly discussed within this framework.
Generalized Cahn‐Hilliard equations based on a microforce balance
Authors: Miranville Alain
Published: April 2003

We present some models of Cahn‐Hilliard equations
based on a microforce balance proposed by M. Gurtin. We then study the existence and uniqueness of solutions.
High-Dimensional Analysis of Evolutionary Autonomous Agents
Authors: Segev Lior , Aharonov Ranit , Meilijson Isaac , Ruppin Eytan
Published: April 2003

This article presents a new approach to the important challenge of localizing function in a neurocontroller. The approach is based on the basic functional contribution analysis (FCA) presented earlier, which assigns contribution values to the elements of the network, such that the ability to predict the network's performance in response to multi-unit lesions is maximized. These contribution values quantify the importance of each element to the tasks the agent performs. Here we present a generalization of the basic FCA to high-dimensional analysis, using high-order compound elements. Such elements are composed of conjunctions of simple elements. Their usage enables the explicit expression of sets of neurons or synapses whose contributions are interdependent, a prerequisite for localizing the function of complex neurocontrollers. High-dimensional FCA is shown to significantly improve on the accuracy of the basic analysis, to provide new insights concerning the main subsets of simple elements in the network that interact in a complex nonlinear manner, and to systematically reveal the types of interactions that characterize the evolved neurocontroller.
Self-Replicating Machines in Continuous Space with Virtual Physics
Authors: Smith Arnold , Turney Peter , Ewaschuk Robert
Published: April 2003

JohnnyVon is an implementation of self-replicating machines in continuous two-dimensional space. Two types of particles drift about in a virtual liquid. The particles are automata with discrete internal states but continuous external relationships. Their internal states are governed by finite state machines, but their external relationships are governed by a simulated physics that includes Brownian motion, viscosity, and springlike attractive and repulsive forces. The particles can be assembled into patterns that can encode arbitrary strings of bits. We demonstrate that, if an arbitrary seed pattern is put in a soup of separate individual particles, the pattern will replicate by assembling the individual particles into copies of itself. We also show that, given sufficient time, a soup of separate individual particles will eventually spontaneously form self-replicating patterns. We discuss the implications of JohnnyVon for research in nanotechnology, theoretical biology, and artificial life.
Toward a Formalization of Emergence
Authors: Kubí Aleš
Published: April 2003

Emergence is a concept widely used in the sciences, the arts, and engineering. Some effort has been made to formalize it, but it is used in various contexts with different meanings, and a unified theory of emergence is still distant. The ultimate goal of a theory of emergence should include using emergence to model, design, or predict the behavior of multiagent systems. The author proposes a formal definition of a basic type of emergence using a language-theoretic and grammar systems approach. It is shown which types of phenomena can be modeled in this sense and what the consequences are for other more complex phenomena.
RandScape: Complex Images from Simple Algorithms
Authors: Smith Jeremy
Published: April 2003

This letter presents a range of complex patterns, some that seem eerily lifelike, that were produced from some simple algorithms. Some observations are offered that suggest the algorithms are modeling some natural processes.
Artifact & Artifice: Views on Life
Authors: Dorin Alan
Published: April 2003

The views of some artists on what constitutes life are explored, with the aim of challenging those within the artificial life research community to rethink and perhaps expand their own views about the term and its meaningful application. The focus is on the musical works of Steve Reich and the paintings of Wassily Kandinsky. The role of the observer in determining when it is appropriate to label a thing as living is also discussed.
GUESTHOOD AS ETHICAL DECOLONISING RESEARCH METHOD
Authors: Harvey Graham
Published: April 2003

Debates about research methods have often been concerned with the situation of the researcher in relation to those they research among, about or "on." Reiterating the dualisms embedded in Western culture, many of these have privileged allegedly objective distance between researcher and researched, and worried about researchers "going native." This paper argues that researchers are always more than these dualities suggest, and that an acceptance and outworking of an alternative relational position would greatly enhance research and its outcomes. That alternative position is explored in dialogue with the protocols by which Maori convert strangers into guests, while allowing the possibility that strangers might be enemies. Similar protocols and relationships are available among other indigenous people, and more widely. Ethical and decolonising research might find rich resources for resolving some typically Western problems in the enhancement of dialogues and relationships that, reflection suggests, underpin the research experiences of many people (researchers and researched included). The paper argues that benefits will accrue not only to academic communities but also to those with whom they engage.
BUDDHISM, RELIGION, AND THE CONCEPT OF "GOD"
Authors: Pyysiäinen Ilkka
Published: April 2003

It is here argued that, although the Buddha and the buddhas are not regarded as gods by Buddhists, they clearly fulfill the criteria of "counter-intuitive agents" as they have been presented by Pascal Boyer. To the extent that religion can be understood as human thought, action, and experience that involve counter-intuitive representations, Buddhism does not have to be the problematic touchstone for a global concept of religion.
ARYENS ET SÉMITES: QUEL AVENIR? ARCHÉOLOGIES, LANGUES ET VISIONS DU MONDE
Authors: Van Berg Paul-Louis
Published: April 2003

Friedrich Max Mueller thought that the "absurdity" of Aryan myths could be explained by a "disease of language," that is a shift implying that metaphor was taken for reality. Thus, cosmic and meteorological phenomena came to be considered as human beings living human adventures. He found the etiology of this disease in language, and specially in the polysemy and ambiguity of Vedic Sanskrit which he opposed to the limpidity of Hebrew. While the difference between the two languages does exist, the explanation has long been acknowledged to be false. Actually, the opposition becomes understandable if we consider that Indo-Europeans and Semites belong to much wider cultural basins. Indeed, characteristics attributed by Max Mueller to the Aryans also belong to the Altaic cultures, while those assigned to the Semites are shared not only by Hebrews, but also by many other Semitic and by non-Semitic cultures of the Near East. Hence, we can define two large cultural sets north and south of the Black Sea and the Caucasus. In the northern one, Indo-European and Altaic cultures share many traits: organization of space and time, society and knowledge, unreliability of the visible world, conception of the human body, rejection of figuration, for instance. In the southern one, we find radically different conceptions shared by the indigenous Near Eastern cultures. Considering that linguistic communication and ways of thinking are only aspects of these two cultural sets, elaborated separately since the Neolithic and adapted to different conditions of life, we may expect mythologies to reflect these differences and understand that the opposition of Vedic Sanskrit and Hebrew is only a small facet of a global phenomenon.
DID THE HINDUS LACK A SENSE OF HISTORY?
Authors: Sharma Arvind
Published: April 2003

The view that the Hindus do not possess a sense of history has become so commonplace as to virtually achieve the status of an axiom in the study of Indic religion and culture. It is the argument of this paper that this view may stand in need of revision in the light of the epigraphic, literary, and even artisitic evidence presented therein, specially when it is assessed in the context of the various foreign invasions to which India has been subject.
Human neutrophils utilize a Rac/Cdc42-dependent MAPK pathway to direct intracellular granule mobilization toward ingested microbial pathogens
Authors: Zhong Bin , Jiang Kun , Gilvary Danielle L. , Epling-Burnette Pearlie K. , Ritchey Connie , Liu Jinhong , Jackson Rosalind J. , Hong-Geller Elizabeth , Wei Sheng
Published: April 2003

Elevated levels of mitogen-activated protein kinase/extracellular regulatory kinase (MAPK/ERK) activity are frequently found in some cancer cells. In efforts to reduce tumor growth, attempts have been made to develop cancer therapeutic agents targeting the MAPK. Here, by use of biologic, biochemical, and gene manipulation methods in human polymorphonuclear neutrophils (PMNs), we have identified a key pathway important in normal cell function involving MAPK/ERK in PMNs for growth inhibition of Candida albicans. Contact withC albicans triggered MAPK/ERK activation in PMNs within 5 minutes, and blocking of MAPK/ERK activation, either by the pharmacologic reagent PD098059 or by dominant-negative MAPK kinase (MEK) expression via vaccinia viral delivery, suppressed antimicrobial activity. Rac and Cdc42, but not Ras or Rho, were responsible for this MAPK/ERK activation. Expression of dominant-negative Rac (N17Rac) or Cdc42 (N17Cdc42) eliminated not only C albicans– mediated ERK phosphorylation but also phagocytosis and granule migration toward the ingested microbes, whereas dominant-negative Ras (N17Ras) and Rho (N19Rho) did not. PAK1 (p21-activated kinase 1) activation is induced by C albicans, suggesting that PAK1 may also be involved in the Rac1 activation of MAPK/ERK. We conclude from these data that Rac/Cdc42-dependent activation of MAPK/ERK is a critical event in the immediate phagocytic response of PMNs to microbial challenge. Therefore, use of MAPK pharmacologic inhibitors for the treatment of cancer may result in the interruption of normal neutrophil function. A balance between therapeutic outcome and undesirable side effects must be attained to achieve successful and safe anticancer therapy.
Novel epinephrine and cyclic AMP-mediated activation of BCAM/Lu-dependent sickle (SS) RBC adhesion
Authors: Hines Patrick C. , Zen Qin , Burney Sharran N. , Shea Deborah A. , Ataga Kenneth I. , Orringer Eugene P. , Telen Marilyn J. , Parise Leslie V.
Published: April 2003

The vasoocclusive crisis is the major clinical feature of sickle cell anemia, which is believed to be initiated or sustained by sickle (SS) red blood cell (RBC) adhesion to the vascular wall. SS RBCs, but not unaffected (AA) RBCs, adhere avidly to multiple components of the vascular wall, including laminin. Here we report a novel role for epinephrine and cyclic adenosine monophosphate (cAMP) in the regulation of human SS RBC adhesiveness via the laminin receptor, basal cell adhesion molecule/Lutheran (BCAM/Lu). Our data demonstrate that peripheral SS RBCs contain greater than 4-fold more cAMP than AA RBCs under basal conditions. Forskolin or the stress mediator epinephrine further elevates cAMP in SS RBCs and increases adhesion of SS RBCs to laminin in a protein kinase A (PKA)–dependent manner, with the low-density population being the most responsive. Epinephrine-stimulated adhesion to laminin, mediated primarily via the β2-adrenergic receptor, occurred in SS RBC samples from 46% of patients and was blocked by recombinant, soluble BCAM/Lu, implicating this receptor as a target of cAMP signaling. Thus, these studies demonstrate a novel, rapid regulation of SS RBC adhesion by a cAMP-dependent pathway and suggest that components of this pathway, particularly PKA, the β2-adrenergic receptor, and BCAM/Lu, should be further explored as potential therapeutic targets to inhibit SS RBC adhesion.
Regulation of neutrophil and eosinophil secondary granule gene expression by transcription factors C/EBPε and PU.1
Authors: Gombart Adrian F. , Kwok Scott H. , Anderson Karen L. , Yamaguchi Yuji , Torbett Bruce E. , Koeffler H. Phillip
Published: April 2003

In the bone marrow of C/EBPε−/− mice, expression of neutrophil secondary and tertiary granule mRNAs is absent for lactoferrin (LF), neutrophil gelatinase (NG), murine cathelinlike protein (MCLP), and the cathelin B9; it is severely reduced for neutrophil collagenase (NC) and neutrophil gelatinase-associated lipocalin (NGAL). In addition, the expression of eosinophil granule genes, major basic protein (MBP), and eosinophil peroxidase (EPX) is absent. These mice express C/EBPα, C/EBPβ, and C/EBPδ in the bone marrow at levels similar to those of their wild-type counterparts, suggesting a lack of functional redundancy among the family in vivo. Stable inducible expression of C/EBPε and C/EBPα in the murine fibroblast cell line NIH 3T3 activated expression of mRNAs for B9, MCLP, NC, and NGAL but not for LF. In transient transfections of C/EBPε and C/EBPα, B9 was strongly induced with weaker induction of the other genes. C/EBPβ and C/EBPδ proteins weakly induced B9 expression, but C/EBPδ induced NC expression more efficiently than the other C/EBPs. The expression of MBP was inefficiently induced by C/EBPε alone and weakly induced with C/EBPε and GATA-1, but the addition of PU.1 resulted in a striking cooperative induction of MBP in NIH 3T3 cells. Mutation of a predicted PU.1 site in the human MBP promoter-luciferase reporter construct abrogated the response to PU.1. Gel-shift analysis demonstrated binding of PU.1 to this site. MBP and EPX mRNAs were absent in a PU.1-null myeloid cell line established from the embryonic liver of PU.1−/− mice. Restitution of PU.1 protein expression restored MBP and EPX protein expression. This study demonstrates that C/EBPε is essential and sufficient for the expression of a particular subset of neutrophil secondary granule genes. Furthermore, it indicates the importance of PU.1 in the cooperative activation of eosinophil granule genes.
Involvement of ABC7 in the biosynthesis of heme in erythroid cells: interaction of ABC7 with ferrochelatase
Authors: Taketani Shigeru , Kakimoto Kazuhiro , Ueta Hiromi , Masaki Ryuichi , Furukawa Takako
Published: April 2003

A mitochondrial half-type ATP-binding cassette (ABC) protein, ABC7, plays a role in iron homeostasis in mitochondria, and defects in human ABC7 were shown to be responsible for the inherited disease X-linked sideroblastic anemia/ataxia. We examined the role of ABC7 in the biosynthesis of heme in erythroid cells where hemoglobin is a major product of iron-containing compounds. RNA blots showed that the amount of ABC7 mRNA in dimethylsulfoxide (Me2SO)-treated mouse erythroleukemia (MEL) cells increased markedly in parallel with the induction of the mRNA expression of ferrochelatase, the last enzyme in the pathway to synthesize heme. The transfection of the antisense oligonucleotide to mouse ABC7 mRNA into Me2SO-treated MEL cells led to a decrease of heme production, as compared with sense oligonucleotide–transfected cells. ABC7 protein was shown to be colocalized with ferrochelatase in mitochondria, as assessed by immunostaining. Furthermore, in vitro and in vivo pull-down assays revealed that ABC7 protein is interacted with the carboxy-terminal region containing the iron-sulfur cluster of ferrochelatase. The transient expression of ABC7 in mouse embryo liver BNL-CL2 cells resulted in an increase in the activity and level of ferrochelatase and thioredoxin, a cytosolic protein containing iron-sulfur. These increases were also observed in MEL cells stably expressing ABC7. When ABC7 transfectants were treated with Me2SO, an increase in cellular heme concomitant with a marked induction of the expression of ferrochelatase was observed. The extent of these increases was 3-fold greater than in control cells. The results indicated that ABC7 positively regulates not only the expression of extramitochondrial thioredoxin but also that of an intramitochondrial iron-sulfur–containing protein, ferrochelatase. Then, the expression of ABC7 contributes to the production of heme during the differentiation of erythroid cells.
Factors affecting antibody levels after allogeneic hematopoietic cell transplantation
Authors: Storek Jan , Viganego Federico , Dawson Monja A. , Herremans M. M. P. Tineke , Boeckh Michael , Flowers Mary E. D. , Storer Barry , Bensinger William I. , Witherspoon Robert P. , Maloney David G.
Published: April 2003

To obtain insight into the mechanism(s) of posttransplantation humoral immunodeficiency, we evaluated factors affecting serum antibody levels against polio, tetanus, Haemophilus influenzae, andStreptococcus pneumoniae in 87 patients. Patients with hematologic malignancies were randomized to receive marrow versus blood stem cells, which contain approximately 10 times more lymphocytes than marrow. Blood stem cell recipients did not have higher antibody levels than marrow recipients. Recipient pretransplantation antibody levels were correlated with the posttransplantation levels, especially in the first 6 months after transplantation when the correlation coefficients typically exceeded 0.6. Donor pretransplantation antibody levels had less of a correlation with posttransplantation levels in the recipient. Patient or donor age, total body irradiation, and graft-versus-host disease or its treatment appeared to have no effect. In conclusion, antibody levels in the first year after transplantation are affected primarily by pretransplantation antibody levels in the recipient and, to a lesser degree, in the donor. These findings suggest that immunization of the recipient and the donor before transplantation may be more effective in improving antibody immunity after transplantation than manipulating graft-versus-host disease, changing conditioning, or increasing the number of lymphocytes in the graft.
Prenatal and postnatal myeloid cells demonstrate stepwise progression in the pathogenesis of MLL fusion gene leukemia
Authors: Johnson Jennifer J. , Chen Weili , Hudson Wendy , Yao Qing , Taylor Marnie , Rabbitts Terence H. , Kersey John H.
Published: April 2003

The steps to leukemia following an in utero fusion ofMLL (HRX, ALL-1) to a partner gene in humans are not known. Introduction of the Mll-AF9 fusion gene into embryonic stem cells results in leukemia in mice with cell-type specificity similar to humans. In this study we used myeloid colony assays, immunophenotyping, and transplantation to evaluate myelopoiesis in Mll-AF9 mice. Colony assays demonstrated that both prenatal and postnatal Mll-AF9 tissues have significantly increased numbers of CD11b+/CD117+/Gr-1+/− myeloid cells, often in compact clusters. The self-renewal capacity of prenatal myeloid progenitors was found to decrease following serial replating of colony-forming cells. In contrast, early postnatal myeloid progenitors increased following replating; however, the enhanced self-renewal of early postnatal myeloid progenitor cells was limited and did not result in long-term cell lines or leukemia in vivo. Unlimited replating, long-term CD11b/Gr-1+ myeloid cell lines, and the ability to produce early leukemia in vivo in transplantation experiments, were found only in mice with overt leukemia. Prenatal Mll-AF9tissues had reduced total (mature and progenitor) CD11b/Gr-1+ cells compared with wild-type tissues. Colony replating, immunophenotyping, and cytochemistry suggest that any perturbation of cellular differentiation from the prenatal stage onward is partial and largely reversible. We describe a novel informative in vitro and in vivo model system that permits study of the stages in the pathogenesis of Mll fusion gene leukemia, beginning in prenatal myeloid cells, progressing to a second stage in the postnatal period and, finally, resulting in overt leukemia in adult animals.
AML1/MTG8 oncogene suppression by small interfering RNAs supports myeloid differentiation of t(8;21)-positive leukemic cells
Authors: Heidenreich Olaf , Krauter Jürgen , Riehle Heidemarie , Hadwiger Philipp , John Matthias , Heil Gerhard , Vornlocher Hans-Peter , Nordheim Alfred
Published: April 2003

The translocation t(8;21) yields the leukemic fusion gene AML1/MTG8 and is associated with 10%-15% of all de novo cases of acute myeloid leukemia. We demonstrate the efficient and specific suppression of AML1/MTG8 by small interfering RNAs (siRNAs) in the human leukemic cell lines Kasumi-1 and SKNO-1. siRNAs targeted against the fusion site of the AML1/MTG8 mRNA reduce the levels of AML1/MTG8 without affecting the amount of wild-type AML1. These data argue against a transitive RNA interference mechanism potentially induced by siRNAs in such leukemic cells. Depletion of AML1/MTG8 correlates with an increased susceptibility of both Kasumi-1 and SKNO-1 cells to tumor growth factor β1 (TGFβ1)/vitamin D3–induced differentiation, leading to increased expression of CD11b, macrophage colony-stimulating factor (M-CSF) receptor, and C/EBPα (CAAT/enhancer binding protein). Moreover, siRNA-mediated AML1/MTG8 suppression results in changes in cell shape and, in combination with TGFβ1/vitamin D3, severely reduces clonogenicity of Kasumi-1 cells. These results suggest an important role for AML1/MTG8 in preventing differentiation, thereby propagating leukemic blast cells. Therefore, siRNAs are promising tools for a functional analysis of AML1/MTG8 and may be used in a molecularly defined therapeutic approach for t(8;21)-positive leukemia.