bluuebunny/crossref_metadata_2025 huggingface dataset:
Bile bilirubin pigment analysis in disorders of bilirubin metabolism in early infancy
Authors: Lee W S , McKiernan P J , Beath S V , Preece M A , Baty D , Kelly D A , Burchell B , Clarke D J
Published: July 2002

BACKGROUND

Early and accurate diagnosis of Crigler–Najjar syndrome, which causes prolonged unconjugated hyperbilirubinaemia in infancy, is important, as orthotopic liver transplantation is the definitive treatment.

AIM

To determine whether bilirubin pigment analysis of bile in infants with prolonged unconjugated hyperbilirubinaemia provides useful diagnostic information in the first 3 months of life.

METHODS

Retrospective review of patients with prolonged unconjugated hyperbilirubinaemia referred to the liver unit, Birmingham Children's Hospital, for the diagnosis of Crigler–Najjar syndrome. Bile bilirubin pigment composition was determined by high performance liquid chromatography. Initial diagnoses were made based on the result of bile bilirubin pigment composition. Final diagnoses were made after reviewing the clinical course, response to phenobarbitone, repeat bile bilirubin pigment composition analysis, and genetic studies.

RESULTS

Between 1992 and 1999, nine infants aged less than 3 months of age with prolonged hyperbilirubinaemia underwent bile bilirubin pigment analyses. Based on these, two children were diagnosed with Crigler–Najjar syndrome (CNS) type 1, six with CNS type 2, and one with Gilbert's syndrome. Five children whose initial diagnosis was CNS type 2 had resolution of jaundice and normalisation of serum bilirubin after discontinuing phenobarbitone, and these cases were thought to be normal or to have Gilbert's syndrome. One of the initial cases of CNS type 1 responded to phenobarbitone with an 80% reduction in serum bilirubin consistent with CNS type 2. In all, the diagnoses of six cases needed to be reviewed.

CONCLUSIONS

Early bile pigment analysis, performed during the first 3 months of life, often shows high levels of unconjugated bilirubin or bilirubin monoconjugates, leading to the incorrect diagnosis of both type 1 and type 2 Crigler–Najjar syndrome.
Excess molar enthalpies of mixtures of methyl derivatives of polyethylene glycol with 1-alkanol at 298.15 K and 101.3 kPa
Authors: de Ruiz Holgado M EF , Fernandez J , Paz Andrade M I , Arancibia E L
Published: July 2002

Excess molar enthalpies (H E) of the binary mixtures containing tetraethylene glycol dimethyl ether (TEGDME) or polyethylene glycol 350 monomethyl ether with a 1-alkanol (1-propanol, 1-butanol, or 1-pentanol) at 298.15 K and atmospheric pressure were measured using a Calvet microcalorimeter. All the H E experimental values were positive and increase as the 1-alkanol length increases. The results are discussed qualitatively in terms of molecular interactions. The UNIFAC and DISQUAC group contribution models have been used to compare the predicted and the experimental values.Key words: excess enthalpy, 1-alkanol, polyether, binary system.
POISSON-NIJENHUIS STRUCTURES AND SATO HIERARCHY
Authors: MAGNANO G. , MAGRI F.
Published: July 2002

We show that the direct sum of n copies of a Lie algebra is endowed with a sequence of affine Lie-Poisson brackets, which are pairwise compatible and define a multi-Hamiltonian structure; to this structure one can associate a recursion operator and a Kac-Moody algebra of Hamiltonian vector fields. If the initial Lie algebra is taken to be an associative algebra of differential operators, a suitable family of Hamiltonian vector fields reproduce either the n-th Gel'fand-Dikii hierarchy (for n finite) or Sato's hierarchy (for n = ∞). Within the same framework, it is also possible to recover a class of integro-differential hierarchies involving a finite number of fields, which generalize the Gel'fand-Dikii equations and are equivalent to Sato's hierarchy.
GLOBAL CHIRAL VERTEX OPERATORS ON RIEMANN SURFACES
Authors: BONORA L. , TOPPAN F.
Published: July 2002

Using Krichever-Novikov bosonic oscillators we introduce chiral vertex operators on a higher genus Riemann surface Σ. These are essentially the normal-ordered exponential of line integrals of connections in a suitable line bundle over Σ. We discuss globally defined affine algebras in Σ and use chiral vertices to construct level 1 representations of the latter.
EFFICIENT SUPPORT FOR SKELETONS ON WORKSTATION CLUSTERS
Authors: DANELUTTO MARCO
Published: July 2002

Beowulf class clusters are gaining more and more interest as low cost parallel architectures. They deliver reasonable performance at a very reasonable cost, compared to classical MPP machines. Parallel applications are usually developed on clusters using MPI/PVM message passing or HPF programming environments. Here we discuss new implementation strategies to support structured parallel programming environments for clusters based on skeletons. The adoption of structured parallel programming models greatly reduces the time spent in developing new parallel applications on clusters. The adoption of our implementation techniques based on macro data flow allows very efficient parallel applications to be developed on clusters. We discuss experiments that demonstrate the full feasibility of the approach.
SCANNING NEAR-FIELD OPTICAL MICROSPECTROSCOPY OF SINGLE PERYLENE MICROCRYSTALS
Authors: NIITSUMA JUN-ICHI , FUJIMURA TORU , ITOH TADASHI , KASAI HITOSHI , OKADA SHUJI , OIKAWA HIDETOSHI , NAKANISHI HACHIRO
Published: July 2002

Perylene microcrystals are known to show characteristic change in the exciton fluorescence spectra depending on the crystal size less than about 200nm. However, the origin of the size-dependence is not yet clear. In this work, we have studied on individual microcrystals by a scanning near-field optical microscope (SNOM). The samples were prepared by a modified technique based on reprecipitation method. As a result, we could successfully measure the topographic and fluorescence images of perylene microcrystals with the size of ~200nm by SNOM at room temperature. In the fluorescence spectra of the single microcrystals, free and self-trapped exciton bands were successfully observed but they did not show any critical difference from that of the bulk crystals. Some possibility of environmental difference is discussed.
The Flow Rate and Current Density of ERF (Corn Starch-Transformer Oil) Flowing through an Annulus
Authors: Kobayashi K. , Ogura J. , Kodama R. , Sakai T. , Sato M.
Published: July 2002

The purpose of the work is to examine fluidity and to formulate the flow rate and current density of ERF against applied voltage when it flows through a duct, an annulus in this study, under an electric field. In this paper the equations for the ratio of flow rate and current density are proposed for the following cases: a short entrance length or none and a long or sufficient entrance length. The effects of the electrode length, a change in the inner diameter and concentration of an ERF on the fluidity of the ERF are investigated. The equations proposed in this paper accurately represent the experimental results.
NEW REPRESENTATION FOR DESCRIBING LOWERING AND ASCENDING OF AN ELECTRON'S ANGULAR MOMENTUM IN A UNIFORM MAGNETIC FIELD
Authors: FAN HONG-YI , ZOU H. , FAN YUE
Published: July 2002

We construct a new quantum mechanical representation |l,r> for describing an electron's angular momentum in a uniform magnetic field, where l is the eigenvalue of the azimuthal angular momentum Lz and r is the orbit radius of the electron's motion. The ascending and lowering operators for |l,r>→|l± 1,r> are also obtained. Throughout our discussion the <λ| representation is fully employed (see Hong-Yi Fan and Yong Ren, Mod. Phys. Lett.B10, 523 (1996).
DYNAMICAL INSTABILITY OF ONE-DIMENSIONAL MORSE SYSTEM
Authors: OKABE TSUNEYASU , YAMADA HIROAKI
Published: July 2002

Dynamical instability in an one-dimensional many-body system with Morse-type interaction potential is studied by computer simulation. The dynamical instability of the Morse system is caused by two kinds of instability. One is the parametric instability caused by the stochastic fluctuation of positive curvature of a Riemannian manifold and the other is the local instability approximated by the local negative eigenvalues of the Hessian matrix for the potential function. We investigate the energy dependence of the maximal Lyapunov exponent in order to emphasize the characteristic dynamical instability of the Morse system and compare the characteristics with results have been reported in Fermi–Pasta–Ulam system and Lennard–Jones system. We also investigate the energy dependence of the particle diffusion in the Morse system.
THE MAGNETIC BEHAVIOR OF (Y1-xTbx)3Co11B4 INTERMETALLIC COMPOUNDS
Authors: TETEAN R. , POP V. , BURZO E. , DEAC I. GR.
Published: July 2002

The R 3 Co 11 B 4 compounds belong to the R n+1 Co 3n+5 B 2n intermetallic systems. The R 3 Co 11 B 4 borides crystallize in a hexagonal structure of Ce 3 Co 11 B 4 type having the space group P6/mmm. The composition dependencies of the lattice parameters in ( Y 1-x Tb x)3 Co 11 B 4 compounds are linear and different for a and c parameters. The magnetic properties of ( Y 1-x Tb x)3 Co 11 B 4 compounds were investigated in the temperature range 4.2–950 K and external fields up to 10 T. The Y 3 Co 11 B 4 compound is ferromagnetically ordered. For the compounds with x>0, a ferrimagnetic ordering is evidenced. The Curie temperatures increase when yttrium is substituted by terbium, as a consequence of the increase of the exchange interactions in the system. The magnetic behavior of cobalt in the above system is analyzed.
GROWTH OF FINITELY GENERATED POLYNILPOTENT LIE ALGEBRAS AND GROUPS, GENERALIZED PARTITIONS, AND FUNCTIONS ANALYTIC IN THE UNIT CIRCLE
Authors: PETROGRADSKY V. M.
Published: July 2002

Recently, the author has suggested a series of dimensions of algebras which includes as first terms dimension of a vector space, Gelfand–Kirillov dimension, and superdimension. These dimensions enabled us to describe the change of the growth in the transition from a Lie algebra to its universal enveloping algebra. In fact, this is a result on some generalized partitions. In this paper, we obtain more precise asymptotics for generalized partitions. As a main application, we obtain more precise asymptotics for the growth of free polynilpotent finitely generated Lie algebras. As a corollary, we specify the asymptotic growth of the lower central series ranks for free polynilpotent finitely generated groups. We essentially use Hilbert–Poincaré series and some facts on the growth of functions analytic in the unit circle. By the growth of such functions, we mean their growth when the variable tends to 1. Finally, we study two kinds of p-central series for free polynilpotent finitely generated groups. We obtain asymptotics for the ranks of these series, in one case we have an example of a polynomial, but not rational growth.
THE KINETICS AND INFRARED SPECTROSCOPY OF C1 HYDROCARBONS ADSORBED ON CLEAN AND OXYGEN-MODIFIED Mo(100)
Authors: WU GEFEI , KALTCHEV M. , TYSOE W. T.
Published: July 2002

The surface infrared spectra (700–2300 cm -1) of CH 3 I , CD 3 I , CH 2 I 2 and CD 2 I 2 adsorbed on Mo(100) at 80 K have been observed and assigned. The strongest infrared absorption of CH 3 I is the δs( CH 3) mode at 1236 cm -1, which shifts significantly on heating the surface to 135 K, yielding a new peak at 1106 cm -1 indicating the formation of a surface- CH 3 species. This new feature dominates the spectrum after annealing to 160 K and disappears at 235 K, where the TPD results show the desorption of methane. This chemistry was also studied on oxygen-covered Mo(100) with oxygen coverages of 1.0 and 1.5. These were not found to substantially affect the surface chemistry. When CH 2 I 2 is adsorbed on Mo(100), the ω( CH 2) mode at 1107 cm -1 is the strongest feature, and when one heats the sample to 135 K, a new peak appears at 1061 cm -1 which is ascribed to the formation of a surface- CH 2 I species. This peak disappears on heating at about 200 K, where previous ultraviolet-photoelectron-spectroscopic data showed the formation of a surface- C 1 species. No RAIRS data have been reported for adsorbed-methylene species, because of either a low-adsorption cross section or the lack of appropriate symmetry of these modes. The deuterated molecules show the same effects except that peaks are shifted as expected so that ν(H)/ν(D) ~1.35.
DEPOSITION OF PETROLEUM HEAVY ORGANIC COMPOUNDS ON A LOW CARBON STEEL TUBING
Authors: COSULTCHI A. , GARCÍAFIGUEROA E. , MUÑOZ-FLORES A. , GARCÍA-BÓRQUEZ A. , ZEIFERT B. , LARA V. H. , BOSCH P.
Published: July 2002

Reduction of petroleum wells production is often observed and related to the presence of solid deposits adhered on the internal wall of the tubing. A piece of tubing with organic material adhered on its surface was recovered from a Mexican southeastern region well. Its composition and morphology was studied applying scanning electron microscopy with X-ray energy dispersion spectroscopy (SEM-EDXS), X-ray diffraction (XRD) and reflection Fourier Transform Infrared Spectroscopy (FT-IRS). High-condensed hydrocarbons with hydroxyl and carboxyl functional groups and 6.4 wt% total sulfur were found. The adhered-material morphology suggests vitreous solid structure usually identified in polycyclic aromatic compounds. Iron (II, III) oxides and nonstoichiometric sulfides are present; the last, as a corrosion product obtained in petroleum with low H 2 S concentration. Pyrrhotite ( Fe 1-x S ), which exhibits a nonstoichiometric structure, was reported as the active phase of iron oxide catalysts in hydrogen interchange processes.
FUTURE NEEDS IN INTEGRATION OF INFORMATION
Authors: WIEDERHOLD GIO
Published: July 2002

Requirements for continuing progress in Information Systems usability are surveyed and analyzed.
RELATIVE TORSION
Authors: BURGHELEA DAN , FRIEDLANDER LEONID , KAPPELER THOMAS
Published: July 2002

This paper achieves, among other things, the following:

• It frees the main result of [9] from the hypothesis of determinant class and extends this result from unitary to arbitrary representations.

• It extends (and at the same times provides a new proof of) the main result of Bismut and Zhang [3] from finite dimensional representations of Γ to representations on an [Formula: see text]-Hilbert module of finite type ([Formula: see text] a finite von Neumann algebra). The result of [3] corresponds to [Formula: see text].

• It provides interesting real valued functions on the space of representations of the fundamental group Γ of a closed manifold M. These functions might be a useful source of topological and geometric invariants of M.

These objectives are achieved with the help of the relative torsion ℛ, first introduced by Carey, Mathai and Mishchenko [12] in special cases. The main result of this paper calculates explicitly this relative torsion (cf. Theorem 1.1).
COBOL on a PC: a new perspective on a language and its performance
Authors: Jalics Paul J.
Published: July 2002

A comparison of Cobol performance on the PC AT Enhanced versus an IBM 370 mainframe suggests that high-quality PC compiler implementations—combined with the new language features of the Cobol 85 Standard—are improving the PC environment for Cobol to the point where serious applications can now be developed and debugged on the PC, either to be run on the PC itself, or for eventual uploading to a mainframe.
Parallel linear programming in fixed dimension almost surely in constant time
Authors: Alon Noga , Megiddo Nimrod
Published: July 2002

For any fixed dimension
d
, the linear programming problem with
n
inequality constraints can be solved on a probabilistic CRCW PRAM with
O
(
n
) processors almost surely in constant time. The algorithm always finds the correct solution. With
nd
/log
2
d
processors, the probability that the algorithm will not finish within
O
(
d
2
log
2
d
) time tends to zero exponentially with
n
. —
Authors' Abstract
Parallel logic simulation of VLSI systems
Authors: Bailey Mary L. , Briner Jack V. , Chamberlain Roger D.
Published: July 2002

Fast, efficient logic simulators are an essential tool in modern VLSI system design. Logic simulation is used extensively for design verification prior to fabrication, and as VLSI systems grow in size, the execution time required by simulation is becoming more and more significant. Faster logic simulators will have an appreciable economic impact, speeding time to market while ensuring more thorough system design testing. One approach to this problem is to utilize parallel processing, taking advantage of the concurrency available in the VLSI system to accelerate the logic simulation task.

Parallel logic simulation has received a great deal of attention over the past several years, but this work has not yet resulted in effective, high-performance simulators being available to VLSI designers. A number of techniques have been developed to investigate performance issues: formal models, performance modeling, empirical studies, and prototype implementations. Analyzing reported results of these techniques, we conclude that five major factors affect performance: synchronization algorithm, circuit structure, timing granularity, target architecture, and partitioning. After reviewing techniques for parallel simulation, we consider each of these factors using results reported in the literature. Finally we synthesize the results and present directions for future research in the field.
A general explanation component for conceptual modeling in CASE environments
Authors: Gulla Jon Atle
Published: July 2002

In information systems engineering, conceptual models are constructed to assess existing information systems and work out requirements for new ones. As these models serve as a means for communication between customers and developers, it is paramount that both parties understand the models, as well as that the models form a proper basis for the subsequent design and implementation of the systems. New CASE environments are now experimenting with formal modeling languages and various techniques for validating conceptual models, though it seems difficult to come up with a technique that handles the linguistic barriers between the parties involved in a satisfactory manner. In this article, we discuss the theoretical basis of an explanation component implemented for the PPP CASE environment. This component integrates other validation techniques and provides a very flexible natural-language interface to complex model information. It describes properties of the modeling language and the conceptual models in terms familiar to users, and the explanations can be combined with graphical model views. When models are executed, it can justify requested inputs and explain computed outputs by relating trace information to properties of the models.
TeleNotes
Authors: Whittaker Steve , Swanson Jerry , Kucan Jakov , Sidner Candy
Published: July 2002

Communication theories and technology have tended to focus on extended, formal meetings and have neglected a prevalent and vital form of workplace communication—namely, lightweight communication. Unlike formal, extended meetings, lightweight interaction is brief, informal, unplanned, and intermittent. We analyze naturalistic data from a study of work-place communication and derive five design criteria for lightweight interaction systems. These criteria require that systems for lightweight interaction support
conversational tracking, rapid connection
, the ability to
leave a message, context management,
and
shared real-time objects
. Using these criteria, we evaluate existing interpersonal communications technologies. We then describe an implementation of a system (TeleNotes) that is designed to support lightweight interaction by meeting these criteria. The interface metaphor allows communications to be based around desktop objects, resembling “sticky notes.” These objects are also organized into “desktop piles” to support conversational threads and provide mechanisms for initiating real-time audio, video, and application sharing. We conducted informal user testing of several system prototypes. Based on our findings, outstanding issues concerning theory and systems design for communication systems are outlined—in particular, with regard to the issue of managing conversations over time.
Shading models for point and linear sources
Authors: Nishita Tomoyuki , Okamura Isao , Nakamae Eihachiro
Published: July 2002

The degree of realism of the shaded image of a tree-dimensional scene depends on the successful simulation of shading effects. The shading model has two main ingredients, properties of the surface and properties of the illumination falling on it. Most previous work has concentrated on the former rather than the latter.

This paper presents an improved version for generating scenes illuminated by point and linear light sources. The procedure can include intensity distributions for point light sources and output both umbrae and penumbrae for linear light sources, assuming thr environment is composed of convex polyhedra. This paper generalizes Crow's procedure for computing shadow volumes caused by the end points of the linear source results in an easy determination of the reions of penumbrae and umbrae on the face prior to shading calculation.

This paper also discusses a method for displaying illuminance distribution on a shaded image aby using colored isolux contours.
The patchwork rejection technique for sampling from unimodal distributions
Authors: Stadlober Ernst , Zechner Heinz
Published: July 2002

We report on both theoretical developments and comutational experience with the
patchwork rejection
technique in Zechner and Stadlober [1993] and Zechner [1997]. The basic approach is due to Minh [1988], who suggested a special sampling method for the gamma distribution. The method's general objective is to rearrange the area below the density of histogram
f
(
x
) in the body of the distribution by certain point reflections such that variates may be generated efficiently within a large center interval. This is carried out via uniform hat functions, combined with minorizing rectangles for immediate acceptance of one transformed uniform deviate. The remaining tails of
f
(
x
) are covered by exponential functions. Experiments show that patchwork rejection algorithms are in general faster than their competitors at the cost of higher set-up times.
Matrix Inversion Using Parallel Processing
Authors: Pease Marshall C.
Published: July 2002

Two general methods of matrix inversion, Gauss's algorithm and the method of bordering, are analyzed from the viewpoint of their adaptability for parallel computation. The analysis is not based on any specific type of parallel processor; its purpose is rather to see if parallel capabilities could be used effectively in matrix inversion.

It is shown that both methods are indeed able to make effective use of parallel capability. With reasonable assumptions on the parallelism that is available, the speeds of the two methods are roughly comparable. The two methods, however, make use of different kinds of parallelism.

To implement Gauss's algorithm we would like to have (a) parallel transfer capability for
n
numbers, if the matrix is
n
X
n
, (b) the capability for parallel multiplication of the accessed numbers by a common multiplier, and (c) parallel additive read-in capability. For the method of bordering, we need, primarily, the capability of forming the Euclidean inner product of two
n
-dimensional real vectors. The latter seems somewhat harder to implement, but, because it is an operation that is fundamental to linear algebra in general, it is one that might be made available for other purposes. If so, then the method of bordering becomes of interest.
Grouping and parameterizing irregularly spaced points for curve fitting
Authors: Goshtasby A. Ardeshir
Published: July 2002

Given a large set of irregularly spaced points in the plane, an algorithm for partitioning the points into subsets and fitting a parametric curve to each subset is described. The points could be measurements from a physical phenomenon, and the objective in this process could be to find patterns among the points and describe the phenomenon analytically. The points could be measurements from a geometric model, and the objective could be to reconstruct the model by a combination of parametric curves. The algorithm proposed here can be used in various applications, especially where given points are dense and noisy. Examples demonstrating the behavior of the algorithm under noise and density of the points are presented and discussed.
A quadtree medial axis transform
Authors: Samet Hanan
Published: July 2002

As printed

Quadtree skeletons are exact representations of the image and are used because they are observed to yield space efficiently and a decreased sensitivity to shifts in contrast with the quadtree. The QMAT can be used as the underlying representation when solving most problems that can be solved by using a quadtree. An algorithm is presented for the computation of the QMAT of a given quadtree by only examining each BLACK node's adjacent and abutting neighbors.

Corrected Abstract (published as corrigendum in CACM 27, 2 (February 1984) p. 151)

The skeletal and medial axis transform concepts used in traditional image processing representations are adapted to the quadtree representation. The result is the definition of of a new data structure termed the Quadtree Medial Axis Transform (QMAT). A QMAT results in a partition of the image into a set of nondisjoint squares having sides whose lengths are sums of powers of 2 rather than, as is the case with quadtrees, a set of disjoint squares having sides of lengths which are powers of 2. The motivation is not to study skeletons for the usual purpose of obtainings approximations of the image. Instead, quadtree skeletons are exact representations of the image and are used because they are observed to yield space efficiency and a decreased sensitvity to shifts in contrast with the quadtree. The QMAT can be used as the underlying representation when solving most problems that can be solved by using a quadtree. An algorithm is presented for the computation of the QMAT of a given quadtree by only examining each BLACK node's adjacent and abutting neighbors. Analysis of the algorithm reveals an average execution time proportional to the complexity of the image, i.e., the number of BLACK blocks.
A policy-driven scheduler for a time-sharing system
Authors: Bernstein A. J. , Sharp J. C.
Published: July 2002

The services received by a process from a time-sharing operating system can be characterized by a resource count ∑
w

i

R

ij

where
R

ij

is the number of units of service received by process
j
from resource
i
and
w

i

is the cost per unit of the service. Each class of users can be characterized by a policy function which specifies the amount of service a user who belongs to this class should receive as a function of time. Priority changes dynamically as a function of the difference between the service promised to the user by the policy function and the service he actually receives.

A scheduling and swapping algorithm which keeps the resource count of each process above its policy function will provide the specified level of service. Overhead can be reduced by avoiding swaps of processes which have received at least this level of service. The algorithm has been implemented in a general purpose operating system, and it has provided significantly better service to interactive and to batch jobs than the previous scheduler.
On arithmetic expressions and trees
Authors: Redziejowski R. R.
Published: July 2002

A description is given of how a tree representing the evaluation of an arithmetic expression can be drawn in such a way that the number of accumulators needed for the computation can be represented in a straightforward manner. This representation reduces the choice of the best order of computation to a specific problem under the theory of graphs. An algorithm to solve this problem is presented.
A comparison of techniques for the specification of external system behavior
Authors: Davis Alan M.
Published: July 2002

The elimination of ambiguity, inconsistency, and incompleteness in a Software Requirements Specification (SRS) document is inherently difficult, due to the use of natural language. The focus here is a survey of available techniques designed to reduce these negatives in the documentation of a software product's external behavior.
Bounded concurrent timestamp systems using vector clocks
Authors: Haldar Sibsankar , Vitányi Paul
Published: July 2002

Shared registers are basic objects used as communication mediums in asynchronous concurrent computation. A concurrent timestamp system is a higher typed communication object, and has been shown to be a powerful tool to solve many concurrency control problems. It has turned out to be possible to construct such higher typed objects from primitive lower typed ones. The next step is to find efficient constructions. We propose a very efficient wait-free construction of bounded concurrent timestamp systems from 1-writer shared registers. This finalizes, corrects, and extends a preliminary bounded multiwriter construction proposed by the second author in 1986. That work partially initiated the current interest in wait-free concurrent objects, and introduced a notion of discrete vector clocks in distributed algorithms.
A workstation model for an interactive graphics system
Authors: Heck Mike , Plaehn Martin
Published: July 2002

By introducing the concept of an abstract graphics device called the workstation, an existing graphics system is generalized to support multiple devices in applications software.
Compression, information theory, and grammars: a unified approach
Authors: Bookstein Abraham , Klein Shmuel T.
Published: July 2002

Text compression is of considerable theoretical and practical interest. It is, for example, becoming increasingly important for satisfying the requirements of fitting a large database onto a single CD-ROM. Many of the compression techniques discussed in the literature are model based. We here propose the notion of a formal grammar as a flexible model of text generation that encompasses most of the models offered before as well as, in principle, extending the possibility of compression to a much more general class of languages. Assuming a general model of text generation, a derivation is given of the well known Shannon entropy formula, making possible a theory of information based upon text representation rather than on communication. The ideas are shown to apply to a number of commonly used text models. Finally, we focus on a Markov model of text generation, suggest an information theoretic measure of similarity between two probability distributions, and develop a clustering algorithm based on this measure. This algorithm allows us to cluster Markov states, and thereby base our compression algorithm on a smaller number of probability distributions than would otherwise have been required. A number of theoretical consequences of this approach to compression are explored, and a detailed example is given.
Two remarks on Tau-splines
Authors: Lasser Dieter
Published: July 2002

We present a Bézier representation of τ-splines, curvature and torsion-continuous quintics, which were introduced in CAGD by Hagen in 1985 [32]. Explicit formulas are given for the conversion from Bézier representation to τ-spline representation, and vice versa. Thus, by embedding the Bézier representation in a Β-spline representation of curvature and torsion-continuous quintic spline curves, given in [20], a Β-spline-Bézier representation of τ-splines results.

Second, positivity conditions for the design parameters of the Bézier representation and certain ranges of tension values are derived, which ensure properties like the convex hull and the variation-diminishing property of the Β-spline-Bézier representation.
Quartic Beta-splines
Authors: Joe Barry
Published: July 2002

Quartic Beta-splines have third-degree arc-length or geometric continuity at simple knots and are determined by three β or shape parameters. We present a general explicit formula for quartic Beta-splines, and determine and illustrate the effects of varying the β parameters on the shape of a quartic Beta-spline curve. We show that quartic (and higher degree) rational Beta-splines with arc-length continuity satisfy the same continuity conditions as (nonrational) Beta-splines. We also show that the torsion continuous spline curves presented by Boehm ("Smooth Curves and Surfaces.” In
Geometric Modeling: Algorithms and New Trends
, G. E. Farin, Ed. SIAM, Philadelphia, Pa., 1987, pp. 175-184.) are equivalent to nonrational quartic Beta-spline curves, and determine the relationship between the shape parameters for the two types of curves. Finally, we present an algorithm for inserting a new knot and determining the refined control polygon.
STUDIES OF MULTICOMPONENT OXIDE FILMS AND LAYERED HETEROSTRUCTURE GROWTH PROCESSES VIA IN SITU, TIME-OF-FLIGHT ION SCATTERING AND DIRECT RECOIL SPECTROSCOPY
Authors: Auciello Orlando , Krauss Alan R. , Im Jaemo , Schultz J. Albert
Published: July 2002

▪ Abstract  The understanding of film growth processes is critical for fabricating a variety of thin film-based devices. Many novel film-based devices require growth of films in background gas atmospheres such as oxygen and nitrogen for oxide or nitride films. The studies of film growth processes in background gas environments require special analytical techniques. We discuss a novel time-of-flight ion scattering and direct recoil spectroscopy (TOF-ISARS) technique developed in our laboratory that is capable of providing a wide range of information including film composition and surface structure during growth, at the atomic scale. We also discuss recent work focused on the growth of ferroelectric thin films and their integration with electrode layers relevant to the fabrication of ferroelectric capacitors.
NEUROBIOLOGICAL CONSTRAINTS ON BEHAVIORAL MODELS OF MOTIVATION
Authors: Nader Karim , Bechara Antoine , van der Kooy Derek
Published: July 2002

▪ Abstract  The application of neurobiological tools to behavioral questions has produced a number of working models of the mechanisms mediating the rewarding and aversive properties of stimuli. The authors review and compare three models that differ in the nature and number of the processes identified. The dopamine hypothesis, a single system model, posits that the neurotransmitter dopamine plays a fundamental role in mediating the rewarding properties of all classes of stimuli. In contrast, both nondeprived/deprived and saliency attribution models claim that separate systems make independent contributions to reward. The former identifies the psychological boundary defined by the two systems as being between states of nondeprivation (e.g. food sated) and deprivation (e.g. hunger). The latter identifies a boundary between liking and wanting systems. Neurobiological dissociations provide tests of and explanatory power for behavioral theories of goal-directed behavior.
Design's Own Knowledge
Authors: Narváez Luz María Jiménez
Published: July 2002

Doxa: from the Greek, opinion, way of thinking. According to Parmenides, the world of doxa was the world of the opinions of mortals. When substituted by “what is” for what seems to be, or when mortals concur to manipulate things, or understand themselves, it becomes a falsehood or an error. Husserl held that all expressions are a doxic act in their full sense, i.e, a certainty, a belief. 1

1 Paul Foulquie, Diccionario del lenguaje filosófico (Barcelona: Editorial Labor, 1962), 42.
After Appropriation
Authors: Latrell Craig
Published: July 2002

Much of the critical rhetoric surrounding intercultural performance is accusatory, with the West pictured as plundering other cultures or transforming them into McDisney. Latrell advocates a different, more flexible, and locally based model.
Environmental Organizations: Changing Roles and Functions in Global Politics
Authors: Tamiotti Ludivine
Published: July 2002

This article addresses the transformation of the role played by environmental nongovernmental organizations in global politics. Such a change is placed into a larger framework of growing ecological concerns, the evolving political means to address them, and the overall mutation of the global state system. The relationship among environmental organizations, states, and intergovernmental institutions is framed as being an increasingly strategic one, where states seek to instrumentalize environmental organizations in order to prevail, while environmental organizations seek to take over functions previously held by states.
Clonal variation in the Caucasian rock lizard Lacerta armeniaca and its origin
Authors: Murphy Robert , Fu Jinzhong , Darevsky Ilya , MacCulloch Ross
Published: July 2002

Clonal variation in Lacerta armeniaca was investigated using allozyme electrophoresis and morphology. Among the 35 allozyme loci examined, three were variable, which divided L. armeniaca into four clones. One rare clone of L. armeniaca made up the majority of two populations. This contrasts to rare clones in other parthenogenetic Caucasian rock lizards which typically consist of only one or two individuals. Another rare clone, which showed a striking colouration difference, had different allelic composition at two loci. Although mutation is a possible explanation of the origin of the clonal variation, the alternative, multiple origin, is equally likely.
Nematodes associated with East African Highland cooking bananas and cv. Pisang Awak (Musa spp.) in Central Uganda
Authors: De Waele Dirk , Speijer Paul
Published: July 2002

A survey was conducted at 17 sites in Central Uganda. Suckers were detached from East African Highland cooking bananas (Musa spp., AAA-group) and the cultivar Pisang Awak (Musa spp., ABB-group), and assessed for nematode population densities and root damage. The frequency of occurrence on both Musa groups was Helicotylenchus multicinctus 88%, Radopholus similis 74% and Pratylenchus goodeyi 50%. Helicotylenchus multicinctus and R. similis densities were higher (P ≤ 0.05) on Highland cooking bananas compared to Pisang Awak, while P. goodeyi densities did not differ significantly between the groups. Helicotylenchus multicinctus and R. similis were observed to be the major pests of Highland cooking bananas in Central Uganda, causing extensive root death. Radopholus similis may be the more important of the two, as it was also highly associated with root necrosis.
Variable correction of host defense following gene transfer and bone marrow transplantation in murine X-linked chronic granulomatous disease
Authors: Dinauer Mary C. , Gifford Mary A. , Pech Nancy , Li Ling Lin , Emshwiller Patricia
Published: July 2002

Chronic granulomatous disease (CGD) is an inherited immunodeficiency in which the absence of the phagocyte superoxide-generating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase results in recurrent bacterial and fungal infections. A murine model of X-linked CGD (X-CGD) was used to explore variables influencing reconstitution of host defense following bone marrow transplantation and retroviral-mediated gene transfer. The outcomes of experimental infection with Aspergillus fumigatus, Staphylococcus aureus, orBurkholderia cepacia were compared in wild-type, X-CGD mice, and transplanted X-CGD mice that were chimeric for either wild-type neutrophils or neutrophils with partial correction of NADPH oxidase activity after retroviral-mediated gene transfer. Host defense to these pathogens was improved in X-CGD mice even with correction of a limited number of neutrophils. However, intact protection against bacterial pathogens required relatively greater numbers of oxidant-generating phagocytes compared to protection against A fumigatus. The host response also appeared to be influenced by the relative level of cellular NADPH oxidase activity, particularly forA fumigatus. These results may have implications for developing effective approaches for gene therapy of CGD.
Reduced incidence of thrombosis in mice with hereditary spherocytosis following neonatal treatment with normal hematopoietic cells
Authors: Wandersee Nancy J. , Lee John C. , Deveau Susan A. , Barker Jane E.
Published: July 2002

Thrombosis is a life-threatening complication of hemolytic anemia in humans. Cardiac thrombi are present in all adult α-spectrin–deficient (sph/sph) mice with severe hereditary spherocytosis, providing a model for events preceding thrombosis. The current study evaluated (1) the timing of thrombosis initiation and (2) the effect of postnatal transplantation of normal cells on life span and thrombotic incidence in adult mice. Thrombi are detected histologically following necropsy in untreatedsph/sph mice of various ages and are not observed until 6 weeks of age. Thrombotic incidence increases from 50% at 6 to 7 weeks of age to 100% at 9 weeks of age. As a potential therapy, nonablatedsph/sph neonates were transfused with either genetically marked normal peripheral blood (PB), bone marrow (BM), or both and assessed for donor cells and thrombosis. A single transfusion of PB, with or without BM, significantly increases the percentage ofsph/sph mice that survive to weaning (4 weeks of age). Replacement in all sph/sph recipients is limited to red blood cells (RBCs). RBCs derived from donor PB are lost within 5 weeks. PB plus BM prolongs high-level donor PB cell production better than BM alone. Thrombotic incidence is significantly reduced in allsph/sph mice treated with PB, BM, or both. Hence, the presence of normal blood cells in the peripheral circulation of neonatal and adult sph/sph mice rescues the former and abrogates the development of thrombosis in the latter.
WASP and N-WASP in human platelets differ in sensitivity to protease calpain
Authors: Shcherbina Anna , Miki Hiroaki , Kenney Dianne M. , Rosen Fred S. , Takenawa Tadaomi , Remold-O'Donnell Eileen
Published: July 2002

Mutations of Wiskott-Aldrich syndrome protein (WASP) underlie the severe thrombocytopenia and immunodeficiency of the Wiskott-Aldrich syndrome. WASP, a specific blood cell protein, and its close homologue, the broadly distributed N-WASP, function in dynamic actin polymerization processes. Here it is demonstrated that N-WASP is expressed along with WASP, albeit at low levels, in human blood cells. The presence of approximately 160 nmol/L rapidly acting N-WASP molecules may explain the normal capacity of WASP-negative patient platelets for early agonist-induced aggregation and filopodia formation. Ex vivo experiments revealed a significant difference between WASP and N-WASP in sensitivity to calpain, the Ca++-dependent protease activated in agonist-stimulated platelets. Through the use of a series of calpain-containing broken cell systems, it is shown that WASP is cleaved in a Ca++-dependent reaction inhibitable by calpeptin and E64d and that N-WASP is not cleaved, suggesting that the cleavage of WASP by calpain functions in normal platelets as part of a Ca++-dependent switch mechanism that terminates the surface projection phase of blood cell activation processes.
Functional consequences of naturally occurring mutations in human uroporphyrinogen decarboxylase
Authors: Phillips John D. , Parker Tiffany L. , Schubert Heidi L. , Whitby Frank G. , Hill Christopher P. , Kushner James P.
Published: July 2002

Functional consequences of 12 mutations—10 missense, 1 splicing defect, and 1 frameshift mutation—were characterized in the uroporphyrinogen decarboxylase (URO-D) gene found in Utah pedigrees with familial porphyria cutanea tarda (F-PCT). All but one mutation altered a restriction site in the URO-D gene, permitting identification of affected relatives using a combination of polymerase chain reaction and restriction enzyme digestion. In a bacterial expression system, 3 of the missense mutants were found in inclusion bodies, but 7 were expressed as soluble proteins. Enzymatic activity of soluble, recombinant mutant URO-D genes ranged from 29% to 94% of normal. URO-D mRNA levels in Epstein-Barr–virus transformed cells derived from patients were normal (with the exception of the frameshift mutation) even though protein levels were lower than normal, suggesting that missense mutations generally cause unstable URO-Ds in vivo. The crystal structures of 3 mutant URO-Ds were solved, and the structural consequences of the mutations were defined. All missense mutations reported here and by others were mapped to the crystal structure of URO-D, and structural effects were predicted. These studies define structural and functional consequences of URO-D mutations occurring in patients with F-PCT.
Allogeneic transplantation of CD34+selected cells from peripheral blood from human leukocyte antigen–identical siblings: detrimental effect of a high number of donor CD34+ cells?
Authors: Urbano-Ispizua Alvaro , Carreras Enric , Marı́n Pedro , Rovira Montserrat , Martı́nez Carmen , Fernández-Avilés Francesc , Xicoy Blanca , Hernández-Boluda Juan-Carlos , Montserrat Emili
Published: July 2002

Clinical results after T-cell–depleted allografts might be improved by modifying the graft content of progenitor and accessory cells. Although the association of the number of donor T cells with the clinical outcome has been studied extensively, the optimum number of progenitor cells that should be administered to patients is unknown. The characteristics of 84 consecutive human leukocyte antigen (HLA)–identical sibling transplants of granulocyte colony-stimulating factor (G-CSF)–mobilized peripheral blood progenitor cells depleted of T cells by CD34+ positive selection (allo-PBT/CD34+) were analyzed for their effect on clinical outcome. After a median follow-up of 24 months (range, 1-70 months), 50 patients remain alive (59.5%) and 34 have died (21 [25%] as a result of the transplant and 13 [15.5%] due to disease relapse). The median number of CD34+ cells administered to the patients was 3.9 × 106/kg (range, 1.2-14.3 × 106/kg). A number of CD34+ cells in the inoculum of 1 × 106/kg to 3 × 106/kg was associated with increased survival: 21 of 28 (75%) patients are alive, as compared with 29 of 56 (52%) patients receiving more than 3 × 106/kg (actuarial probability 75% vs. 42%, respectively; P = .01). In the multivariate analysis, the independent prognostic variables for survival were CD34+cell dose 1 × 106/kg to 3 × 106/kg (RR = 4.8; P = .0008), sex-pairing match (RR = 3.2;P = .002), and early stage of disease (RR = 2.8;P = .007). From these results it appears that, in allo-PBT/CD34+ from HLA-identical siblings, a number of CD34+ cells in the inoculum between 1 × 106/kg to 3 × 106/kg is an important factor for better survival, and that higher CD34+ cell doses might be associated with a poorer outcome.