bluuebunny/crossref_metadata_2025 huggingface dataset:
Memory-constrained task scheduling on a network of dual processors
Authors: Fuchs Ken , Kafura Dennis
Published: July 2002

One aspect of network design is the extent to which memory is shared among the processing elements. In this paper a model with limited sharing (only two processors connected to each memory) is analyzed and its performance compared with the performance of two other models that have appeared in the literature. One of these is a model of multiple processors sharing a single memory; the other model considers a multiprocessor configuration in which each processor has its own dedicated memory. The tasks processed by these networks are described by both time and memory requirements. The largest-memory-first (LMF) scheduling algorithm is employed and its performance with respect to an enumerative optimal scheduling algorithm is bounded. On the basis of this measure we conclude that memory sharing is only desirable on very small networks and is disadvantageous on networks of larger size.
Disaggregations in databases
Authors: Abiteboul Serge
Published: July 2002

An algebraic foundation of database schema design is presented. A new database operator, namely, disaggregation, is introduced. Beginning with “free” families, repeated applications of disaggregation and three other operators (matching function, Cartesian product, and selection) yield families of increasingly elaborate structure. In particular, families defined by one join dependency and several “embedded” functional dependencies can be obtained in this manner.
A performance-driven IC/MCM placement algorithm featuring explicit design space exploration
Authors: Esbensen Henrik , Kuh Ernest S.
Published: July 2002

A genetic algorithm for building-block placement of ICs and MCMs is presented that simultaneously minimizes layout area and an Elmore-based estimate of the maximum path delay while trying to meet a target aspect ratio. Explicit design space exploration is performed by using a vector-valued, 3-dimensional cost function and searching for a set of distinct solutions representing the best trade-offs of the cost dimensions. From the output solutions, the designer can choose the solution with the preferred trade-off. In contrast to existing approaches, the required properties of the output solutions are specified without using weights or bounds. Consequently, the practical problems of specifying these quantities are eliminated. Promising experimental results are obtained for various placement problems, including a real-world design. Solution sets representing good, balanced cost trade-offs are found using a reasonable amount of runtime. Furthermore, the performance is shown to be comparable to that of simulated annealing in the special case of 1-dimensional optimization, in which direct comparison is possible.
Evaluating uniform expressions within two steps of minimum parallel time
Authors: Wagner Robert A.
Published: July 2002

Consider an array of Processing Elements [PEs], connected by a 2-dimensional grid network, and holding at most one operand of an expression in each PE. Suppose that each PE is allowed, in any one parallel step, to receive one item of data from any of its four immediate neighbors, and to transmit one datum, as well. How can an associative operator, such as addition, combine all the operands, using as little time for communciation as possible? An expression using such a single operator is termed a uniform expression. When the total number of communication links used is the measure of goodness, this problem becomes a Steiner Tree problem, in the Manhattan Distance metric. When the measure is minimizing the parallel time to completion, a method for solving this problem is given which is optimal to within an additive constant of two time-steps. The method has applications when the operands are matrices, spread over an array of PEs, as well. Some lower bounds for this problem, in more general networks, are also proven.
An efficient ILP-based scheduling algorithm for control-dominated VHDL descriptions
Authors: Münch Michael , Wehn Norbert , Glesner Manfred
Published: July 2002

To adopt behavioral synthesis techniques in existing design flows, the synthesis methodology must provide the designer with a mechanism to specify a component's interface timing. This will permit pre- and postsynthesis validation through cosimulation with other subsystems or even through formal verification. In control-flow dominated designs, additional timing constraints will result in a complex specification/constraint system for which the scheduling problem has been shown to be NP-complete. In this article, we present a mathematical framework for solving a special instance of the scheduling problem in control-flow dominated behavioral VHDL descriptions given that the timing of I/O signals has been completely or partially specified. It is based on a code-transformation approach that fully preserves the VHDL semantics. The scheduling problem is mapped onto an integer linear program (ILP) solvable in polynomial time assuming a restricted partial order on selected statements. It captures both control-flow and timing constraints in a single model and also exploits dataflow information to optimize the statement sequence across basic block boundaries.
The directional parameter plane transform of a height field
Authors: Paglieroni David W.
Published: July 2002

The linear
Parameter Plane Transform (PPT)
of a height field attributes an inverted cone of empty space to each height field cell. In is known that height field ray-tracing efficiency can be improved by traversing rays in steps across inverted cones of empty space. However, steps across inverted cones of empty space along rays close to the base of a steep ridge will be short, even if there are no obstructions along the line of sight, because the cones will be narrow. This weakness can be virtually eliminated by allowing the opening angles of the inverted cones of empty space to vary between sectors, i.e., by directionalizing the linear PPT. An efficient algorithm for computing the linear directional PPT of a height field is given and its properties are investigated.
Efficient householder QR factorization for superscalar processors
Authors: Carrig James J. , Meyer Gerard G. L.
Published: July 2002

To extract the potential promised by superscalar processors, algorithm designers must streamline memory references and allow for efficient data reuse throughout the memory hierarchy. Two parameterized Householder QR factorization algorithms are presented that take into account the caches and registers typical of such processors. Guidelines are developed for choosing parameter values that obtain near-optimal cache and register utilization. The new algorithms are implemented and performance-tuned on an Intel Pentium Pro system, a single thin POWER2 node of the IBM Scalable Parallel system 2 (SP2), and a single R8000 processor of a Silicon Graphs POWER Challenge XL.
Algorithm 774
Authors: Facchinei Francisco , Júdice Joaquim , Soares João
Published: July 2002

We describe a set of Fortran routines for generatig box-constrained nonlinear programming test problems. The technique, as described by Facchinei et al. (this issue), allows the user to control relevant properties of the generated problems
On first-order-logic databases
Authors: Rybiński Henryk
Published: July 2002

The use of first-order logic as database logic is shown to be powerful enough for formalizing and implementing not only relational but also hierarchical and network-type databases. It enables one to treat all the types of databases in a uniform manner. This paper focuses on the database language for heterogeneous databases. The language is shown to be general enough to specify constraints for a particular type of database, so that a specification of database type can be “translated” to the specification given in the database language, creating a “logical environment” for different views that can be defined by users. Owing to the fact that any database schema is seen as a first-order theory expressed by a finite set of sentences, the problems concerned with completeness and compactness of the database logic discussed by Jacobs ("On Database Logic,”
J. ACM 29
,2 (Apr. 1982), 310-332) are avoided.
A timing-driven design and validation methodology for embedded real-time systems
Authors: Dasdan Ali , Ramanathan Dinesh , Gupta Rajesh K.
Published: July 2002

We address the problem of timing constraint derivation and validation for reactive and real-time embedded systems. We assume that such a system is structured into its tasks, and the structure is modeled using a task graph. Our solution uses the timing behavior committed by the environment to the system first to derive the timing constraints on the system's internal behavior and then use them to derive and validate the timing constraints on the system's external behavior. Our solution consists of the following contributions: a generalized task graph model, a comprehensive classification of timing constraints, algorithms for derivation and validation of timing constraints of the system modeled in the generalized task graph model, a codesign methodology that combines the model and the algorithms, and the implementation of this methodology in a tool called RADHA-RATAN. The main advantages of our solution are that it simplifies the problem of ensuring timing correctness of the system by reducing the complexity of the problem from system level to task level, and that it makes the codesign methodology timing-driven in that our solution makes it possible to maintain a handle on the system's timing correctness from very early stages in the system's design flow.
On the reliability of consensus-based fault-tolerant distributed computing systems
Authors: Babaoğlu Özalp
Published: July 2002

The designer of a fault-tolerant distributed system faces numerous alternatives. Using a stochastic model of processor failure times, we investigate design choices such as replication level, protocol running time, randomized versus deterministic protocols, fault detection, and authentication. We use the probability with which a system produces the correct output as our evaluation criterion. This contrasts with previous fault-tolerance results that guarantee correctness only if the percentage of faulty processors in the system can be bounded. Our results reveal some subtle and counterintuitive interactions between the design parameters and system reliability.
An object-oriented approach to database system implementation
Authors: Baroody A. James , DeWitt David J.
Published: July 2002

This paper examines object-oriented programming as an implementation technique for database systems. The object-oriented approach encapsulates the representations of database entities and relationships with the procedures that manipulate them. To achieve this, we first define abstractions of the modeling constructs of the data model that describe their common properties and behavior. Then we represent the entity types and relationship types in the conceptual schema and the internal schema by objects that are instances of these abstractions. The generic procedures (data manipulation routines) that comprise the user interface can now be implemented as calls to the procedures associated with these objects.

A generic procedure model of database implementation techniques is presented and discussed. Several current database system implementation techniques are illustrated as examples of this model, followed by a critical analysis of our implementation technique based on the use of objects. We demonstrate that the object-oriented approach has advantages of data independence, run-time efficiency due to eliminating access to system descriptors, and support for low-level views.
On the ``Reverse Order Law'' Related to the Generalized Inverse of Matrix Products
Authors: Erdelyi Ivan
Published: July 2002

The “reverse order law” related to ordinary inverses of matrix products, i.e., (
AB
)
-1
=
B
-1
A
-1
, is generally not transferable to the generalized inverse. There are, however, applications in which the reverse order law related to the generalized inverse reveals interesting properties in certain classes of matrices.

In this paper, some necessary and sufficient conditions for the reverse order property to hold are given.
Parsing of Graph-Representable Pictures
Authors: Shaw Alan C.
Published: July 2002

A syntax-directed picture analysis system based on a formal picture description scheme is described. The system accepts a description of a set of pictures in terms of a grammar generating strings in a picture description language; the grammar is explicitly used to direct the analysis or parse, and to control the calls on pattern classification routines for primitive picture components. Pictures are represented by directed graphs with labeled edges, where the edges denote elementary picture components and the graph connectivity mirrors the picture component connectivity; blank and don't care “patterns” allow the description of simple relations between visible patterns. The bulk of the paper is concerned with the picture parsing algorithm which is an
n
-dimensional analog of a classical top-down string parser, and an application of an implemented system to the analysis of spark chamber film. The potential benefits of this approach, as demonstrated by the application, include ease of implementation and modification of picture processing systems, and simplification of the pattern recognition problem by automatically taking advantage of contextual information.
A Note on the Effect or the Central Processor Service Time Distribution on Processor Utilization in Multiprogrammed Computer Systems
Authors: Price Thomas G.
Published: July 2002

Upper and lower bounds on processor utilization for the queueing model M/G/1/N are derived. The upper bound is equal to the utilization for constant service times and the lower bound is approached when the average number of operations per busy period approaches one. These bounds show that the form of the processing time distribution can have a substantial effect on processor utilization. We show that the utilization will be near the lower bound if there are a large number of short processing times. The variance does not always give an accurate indication of the effect of the distribution on utilization.
On the use of flexible, rectilinear blocks to obtain minimum-area floorplans in mixed block and cell designs
Authors: Mehta Dinesh P. , Sherwani Naveed
Published: July 2002

This paper presents three minimum-area floorplanning algorithms that use flexible arbitrary rectilinear shapes for the standard cell regions in MBC design. The first algorithm (pure HCST) introduces a grid traversal technique which guarantees a minimum-area floorplan. The second algorithm (Hybrid-BF) uses a combination of HCST and Breadth First (BF) traversals to give a practical solution that approximately places flexible blocks at specified locations calledseeds. The third algorithm (Hybrid-MBF) improves on the shapes of the flexible blocks generated by Hybrid-BF by using a combination of HCST and a Modified Breadth First (MBF) traversal. All three algorithms are polynomial in the number of grid squares. Optimized implementations of Hybrid-BF and Hybrid-MBF required less than two seconds on a SUN SPARCstation 10.
Algorithm 418: calculation of Fourier integrals [D1]
Authors: Einarsson Bo
Published: July 2002

The most commonly used formula for calculating Fourier integrals is Filon's formula, which is based on the approximation of the function by a quadratic in each double interval. In order to obtain a better approximation the cubic spline fit is used in [1]. The obtained formulas do not need the explicit calculation of the spline fit, but in addition to the function values at all intermediate points, the values of the first and second derivatives at the boundary points are required. However, these values are often obtained from symmetry conditions. If the derivatives at the end-points are unknown, they may be calculated from a cubic spline fit, for example by using some exterior points or by using two extra interior conditions for the spline fit. It can also be noted that in certain periodic cases the terms containing the derivatives will cancel, and their values will be superfluous. The use of Algorithm 353 [2] is recommended if the frequency
ω
/
π
is a positive integer and the interval is [0,1]. Test computations reported in [1] indicate that the spline formula is more accurate than Filon's formula. Both are of the fourth order. The expansion of the error term in powers of the step length contains only even powers, and therefore the use of Richardson extrapolation is very efficient.
Computer languages for heuristic processes
Authors: Hormann Aiko
Published: July 2002

The applicability of computers to many problem-solving situations—chess playing, mathematical proofs, music composition, etc.—has been demonstrated. We wish to explore further heuristic processes suggested by human problem-solving activity. One step toward this goal has been the design of a system named ROVER. ROVER refers both to the simulated computer and the information processing language it uses.
Comparison of iterative methods for the calculation of
n
th roots
Authors: Traub J. F.
Published: July 2002

Three iterative methods for calculation of
n
th roots (including one proposed by the author) are compared in two ways: (1) Theoretical convergence estimates are given. (2) A new macro-compiler which estimates machine running time is used to compare the running time of the three methods for a variety of input data.
Bitwise operations
Authors: Strachey C.
Published: July 2002

Recent contributions on the subject of counting the ones or reversing the digits of a binary word have prompted some rather more general observations on bitwise operations which treat each binary digit in a computer word as a separate entity.
A technique for counting ones in a binary computer
Authors: Wegner Peter
Published: July 2002

Standard methods of counting binary
ones
on a computer with a 704 type instruction code require an inner loop which is carried out once for each bit in the machine word. Program 1 (written in SAP language for purposes of illustration) is an example of such a standard program.
Evaluating numbers expressed as strings of English words
Authors: Swift Charles J.
Published: July 2002

Integer numbers can be expressed in English by a series of words such as “one hundred thirty three million two hundred four.” The process indicated by the accompanying flowchart evaluates numbers represented by such a string. To include words up to “billion” requires four terms “Sum

i

.” The multiplications can be done by shifting on a decimal machine.
Greatest common divisors of polynomials given by straight-line programs
Authors: Kaltofen Erich
Published: July 2002

Algorithms on multivariate polynomials represented by straight-line programs are developed. First, it is shown that most algebraic algorithms can be probabilistically applied to data that are given by a straight-line computation. Testing such rational numeric data for zero, for instance, is facilitated by random evaluations modulo random prime numbers. Then, auxiliary algorithms that determine the coefficients of a multivariate polynomial in a single variable are constructed. The first main result is an algorithm that produces the greatest common divisor of the input polynomials, all in straight-line representation. The second result shows how to find a straight-line program for the reduced numerator and denominator from one for the corresponding rational function. Both the algorithm for that construction and the greatest common divisor algorithm are in random polynomial time for the usual coefficient fields and output a straight-line program, which with controllably high probability correctly determines the requested answer. The running times are polynomial functions in the binary input size, the input degrees as unary numbers, and the logarithm of the inverse of the failure probability. The algorithm for straight-line programs for the numerators and denominators of rational functions implies that every degree-bounded rational function can be computed fast in parallel, that is, in polynomial size and polylogarithmic depth.
Enabling crypto
Authors: Weber Arnd
Published: July 2002

Examining the key factors and influences in the development of cryptography.
Optimum polynomial retrieval functions based on the probability ranking principle
Authors: Fuhr Norbert
Published: July 2002

We show that any approach to developing optimum retrieval functions is based on two kinds of assumptions: first, a certain form of representation for documents and requests, and second, additional simplifying assumptions that predefine the type of the retrieval function. Then we describe an approach for the development of optimum polynomial retrieval functions: request-document pairs (

f
l

,

d
m

) are mapped onto description vectors
x
(

f
l

,

d
m

), and a polynomial function
e
(
x
) is developed such that it yields estimates of the probability of relevance P(
R
| x (

f
l

,

d
m

) with minimum square errors. We give experimental results for the application of this approach to documents with weighted indexing as well as to documents with complex representations. In contrast to other probabilistic models, our approach yields estimates of the actual probabilities, it can handle very complex representations of documents and requests, and it can be easily applied to multivalued relevance scales. On the other hand, this approach is not suited to log-linear probabilistic models and it needs large samples of relevance feedback data for its application.
MEIOTIC CHROMOSOME ORGANIZATION AND SEGREGATION IN PLANTS
Authors: Dawe R. Kelly
Published: July 2002

▪ Abstract  During meiosis, homologous chromosomes are brought together to be recombined and segregated into separate haploid gametes. This requires two cell divisions, an elaborate prophase with five substages, and specialized mechanisms that regulate the association of sister chromatids. This review focuses on plant chromosomes and chromosome-associated structures, such as recombination nodules and kinetochores, that ensure accurate meiotic chromosome segregation.
ACYL-COENZYME A:CHOLESTEROL ACYLTRANSFERASE
Authors: Chang T. Y. , Chang Catherine C. Y. , Cheng Dong
Published: July 2002

Due to its presumed role in regulating cellular cholesterol homeostasis, and in various pathophysiological conditions, acyl-coenzyme A:cholesterol acyltransferase (ACAT) has attracted much attention. Cloning the ACAT gene provides the necessary tool to advance molecular studies of this enzyme. The topics reviewed in this chapter include the pathophysiological roles of ACAT, the biochemistry and molecular biology of the ACAT protein and the ACAT gene, and the mode of regulation by sterol or nonsterol agents in mammalian cells. In addition, we present a working model linking the presumed allosteric property of ACAT with cholesterol trafficking into and out of the endoplasmic reticulum.
Synthesis of Native Proteins by Chemical Ligation
Authors: Dawson Philip E. , Kent Stephen B. H.
Published: July 2002

▪ Abstract  In just a few short years, the chemical ligation of unprotected peptide segments in aqueous solution has established itself as the most practical method for the total synthesis of native proteins. A wide range of proteins has been prepared. These synthetic molecules have led to the elucidation of gene function, to the discovery of novel biology, and to the determination of new three-dimensional protein structures by both NMR and X-ray crystallography. The facile access to novel analogs provided by chemical protein synthesis has led to original insights into the molecular basis of protein function in a number of systems. Chemical protein synthesis has also enabled the systematic development of proteins with enhanced potency and specificity as candidate therapeutic agents.
Fc RECEPTORS AND THEIR INTERACTIONS WITH IMMUNOGLOBULINS
Authors: Raghavan Malini , Bjorkman Pamela J.
Published: July 2002

▪ Abstract  Receptors for the Fc domain of immunoglobulins play an important role in immune defense. There are two well-defined functional classes of mammalian receptors. One class of receptors transports immunoglobulins across epithelial tissues to their main sites of action. This class includes the neonatal Fc receptor (FcRn), which transports immunoglobulin G (IgG), and the polymeric immunoglobulin receptor (pIgR), which transports immunoglobulin A (IgA) and immunoglobulin M (IgM). Another class of receptors present on the surfaces of effector cells triggers various biological responses upon binding antibody-antigen complexes. Of these, the IgG receptors (FcγR) and immunoglobulin E (IgE) receptors (FcεR) are the best characterized. The biological responses elicited include antibody-dependent, cell-mediated cytotoxicity, phagocytosis, release of inflammatory mediators, and regulation of lymphocyte proliferation and differentiation. We summarize the current knowledge of the structures and functions of FcRn, pIgR, and the FcγR and FcεRI proteins, concentrating on the interactions of the extracellular portions of these receptors with immunoglobulins.
THE BIOLOGY OF NONFRUGIVOROUS TEPHRITID FRUIT FLIES
Authors: Headrick D. H. , Goeden R. D.
Published: July 2002

▪ Abstract  This review is the first comprehensive treatment of the biology of nonfrugivorous fruit flies of the family Tephritidae. Feeding habits of destructive and useful species, morphology of immature stages, and hypotheses regarding structural homology and the evolutionary biology of nonfrugivorous tephritids are reviewed, including zoogeography and theories involving resource heterogeneity, guild structure, resource partitioning, resource utilization, facultative niche exploitation, extrinsic and intrinsic factors, host associations, seasonal distribution and phenology, aggregative and circumnatal life history strategies, voltinism, diapause, aestivation, oviposition site, clutch size, and supernumerary oviposition.
INSECT PESTS OF PIGEONPEA AND THEIR MANAGEMENT
Authors: Shanower T. G. , Romeis J. , Minja E. M.
Published: July 2002

▪ Abstract  Pigeonpea (Cajanus cajan) is an important crop in semi-arid tropical and subtropical farming systems, providing high quality vegetable protein, animal feed, and firewood. Insect pests feeding on flowers, pods, and seeds are the most important biotic constraint affecting pigeonpea yields. This review summarizes the biology and ecology of the three most important groups of pests: flower- and pod-feeding Lepidoptera, pod-sucking Hemiptera, and seed-feeding Diptera and Hymenoptera. Recent research investigating the complex interactions among pigeonpea, its key pests, and their natural enemies is also reviewed. These relationships have implications on the pest status of individual species and on possible control strategies. Pigeonpea pest management research has focused until recently on the identification and development of resistant cultivars and on chemical control. Future research must focus on environmentally sound pest management strategies that are compatible with the needs and limitations of pigeonpea farmers. Several priority areas for research are suggested.
STRUCTURE, FUNCTION, AND REPLICATION OF SACCHAROMYCES CEREVISIAE TELOMERES
Authors: Zakian Virginia A.
Published: July 2002

▪ Abstract  A combination of classical genetic, biochemical, and molecular biological approaches have generated a rather detailed understanding of the structure and function of Saccharomyces telomeres. Yeast telomeres are essential to allow the cell to distinguish intact from broken chromosomes, to protect the end of the chromosome from degradation, and to facilitate the replication of the very end of the chromosome. In addition, yeast telomeres are a specialized site for gene expression in that the transcription of genes placed near them is reversibly repressed. A surprisingly large number of genes have been identified that influence either telomere structure or telomere function (or both), although in many cases the mechanism of action of these genes is poorly understood. This article reviews the recent literature on telomere biology and highlights areas for future research.
SUN EXPOSURE AND SKIN DISEASE
Authors: Taylor, M.D Charles R. , Sober, M.D Arthur J.
Published: July 2002

▪ Abstract  Sunlight exposure produces a variety of adverse cutaneous effects. Erythema, photosensitivity, and immunologic alterations represent acute events, whereas photoaging and carcinogenesis are long-term consequences. These adverse cutaneous sequelae can be minimized by photoprotection in the form of sun avoidance, regular cover-up with clothing, and sunscreen application. This chapter reviews the diagnosis and treatment of sun-related skin disorders and recommendations for reducing photodamage.
The Spectrum of Human Herpesvirus 6 Infection: From Roseola Infantum to Adult Disease
Authors: Stoeckle Mark Young
Published: July 2002

▪ Abstract  Human herpesvirus 6 is the causative agent of roseola infantum, a generally benign rash illness of infants. Most persons acquire HHV-6 infection by age 2 years, and HHV-6 infection is a common cause of fever and febrile seizures in infants. In adults, primary infection with HHV-6 can produce a mononucleosis-like illness and, more rarely, severe disease, including encephalitis. In addition to primary infections, HHV-6 can cause clinical illness during reactivation, particularly in immunocompromised persons.
NORMAL AND ABNORMAL CONSEQUENCES OF APOPTOSIS IN THE HUMAN HEART
Authors: James Thomas N.
Published: July 2002

▪ Abstract  Knowledge about apoptosis has become essential for understanding many aspects of cardiac structure and function. In the human heart there are major periods of morphogenesis that begin only after birth, and some of these processes recur intermittently for many years. Although the exact mechanisms by which these events are initiated or terminated remain poorly understood, it is clear that their benefits may be mirrored in destructive effects. In this review, selected examples include normal morphogenesis of the cardiac conduction system and the normal postnatal involution of the right ventricle, both of which are mediated by apoptosis. Destructive counterparts include familial heart block ending in fatal arrhythmias, similar results in the long QT syndrome, and the pathogenesis of both Uhl's anomaly and arrhythmogenic right ventricular dysplasia; in each apoptosis is an important factor.
RECOMBINATION IN MAGNAPORTHE GRISEA
Authors: Zeigler Robert S.
Published: July 2002

▪ Abstract  The heterothallic ascomycete, Magnaporthe grisea, is the blast pathogen of rice and about 50 other grasses, and has potential for sexual and asexual reproduction. In most populations, data from mating type, fertility assays, and genotypic diversity strongly suggest that the pathogen is asexual. However, parasexual recombination cannot be ruled out. Chromosome length polymorphisms and translocations may prevent successful meiosis in most populations. Pathogens of millets and some grasses growing with rice appear to be largely genetically isolated, though some gene flow may occur. Sexual fertility has repeatedly been reported in rice pathogens from mountainous regions of South and East Asia. Several means by which sexual fertility may be lost in an agricultural setting are advanced.
NATURAL GENOMIC AND ANTIGENIC VARIATION IN WHITEFLY-TRANSMITTED GEMINIVIRUSES (BEGOMOVIRUSES)
Authors: Harrison BD , Robinson DJ
Published: July 2002

▪ Abstract  Begomoviruses have circular single-stranded DNA genomes, cause many diseases of dicotyledons in areas with warm climates and are transmitted by whiteflies of the Bemisia tabaci complex. Their genomic and antigenic variation represents geography-related lineages that have little relation to host range. Genomic variation resulting from mutation is amplified by acquisition of extra DNA components, pseudo-recombination and recombination, both intraspecific and interspecific. Recombination, especially interspecific recombination, seems the key mechanism for generating novel virus forms, for enhancing biological fitness of pseudo-recombinants derived from closely related species and for maintaining the flow of genetic material among different geminiviruses occurring in the same geographical region. Recent begomovirus epidemics reflect favorable conjunctions of plant, vector, and viral (e.g. emergence of a novel recombinant virus) factors. Such epidemics typically result in co-infection of plants with different begomoviruses, leading to the appearance of further variants, especially recombinants. In their patterns of variation and evolution, begomoviruses differ greatly from plant viruses with RNA genomes.
Toxicological Bases for the Setting of Health-Related Air Pollution Standards
Authors: Lippmann M. , Schlesinger R. B.
Published: July 2002

▪ Abstract  The development of air pollution standards ideally involves the integration of data from the disciplines of epidemiology, controlled clinical studies, and animal toxicology. Epidemiological studies show statistical associations between health outcomes and exposure; they cannot establish a definite cause-effect relationship. The utility of toxicological studies is to establish this relationship. Recently, there was simultaneous promulgation of a new National Ambient Air Quality Standard (NAAQS) for particulate matter <2.5 μm in aerodynamic diameter (PM2.5) and a revised NAAQS for ozone (O3). The O3 NAAQS was based, in part, on a sound foundation of toxicological data from controlled exposure studies in humans and animals. It also relied on epidemiological studies of hospital admissions for respiratory diseases. Such studies also served as important bases for the new PM2.5 NAAQS. However, the most influential bases for the PM NAAQS were the numerous and generally consistent epidemiological studies that associated exposure with premature mortality in susceptible subpopulations and the inability of numerous hypothesized confounding factors to negate the associations. Using ozone and PM as examples, this paper discusses the scientific basis for NAAQS promulgations in situations in which the underlying database differed greatly in the extent of toxicological support.
Estrogen Receptor-α Mediates the Protective Effects of Estrogen Against Vascular Injury
Authors: Pare Gary , Krust Andrée , Karas Richard H. , Dupont Sonia , Aronovitz Mark , Chambon Pierre , Mendelsohn Michael E.
Published: July 2002

Blood vessel cells express the 2 known estrogen receptors, α and β (ERα, ERβ), which are thought to mediate estrogen inhibition of vascular injury and atherosclerosis, but the relative role of ERα and ERβ in these events is controversial. Estrogen inhibits the vascular injury response to the same extent in ovariectomized female wild-type mice and in the original single gene knockout mice for ERα (ERαKO
Chapel Hill
[ERαKO
CH
]) and ERβ (ERβKO
Chapel Hill
[ERβKO
CH
]). In double gene knockout mice generated by crossing these animals (ERα,βKO
CH
), estrogen no longer inhibits medial thickening after vascular injury, but still inhibits vascular smooth muscle cell proliferation and increases uterine weight. The partial retention of estrogen responsiveness in ERα,βKO
CH
mice could be due either to the presence of a novel, unidentified estrogen receptor or to functional expression of an estrogen receptor-α splice variant in the parental ERαKO
CH
mice. To distinguish between these possibilities, we studied recently generated mice fully null for estrogen receptor α (ERαKO
Strasbourg
[ERαKO
St
]) and examined the effect of estrogen on the response to vascular injury. In the present study, we show that after vascular injury in ovariectomized ERαKO
St
mice, estrogen has no detectable effect on any measure of vascular injury, including medial area, proteoglycan deposition, or smooth muscle cell proliferation. These data demonstrate that estrogen receptor-α mediates the protective effects of estrogen on the response to vascular injury.
Selective Serotonin Reuptake Inhibitors and the Risk of Stroke
Authors: Bak Søren , Tsiropoulos Ioannis , Kjærsgaard Jens Ole , Andersen Morten , Mellerup Erling , Hallas Jesper , García Rodríguez Luis Alberto , Christensen Kaare , Gaist David
Published: July 2002

Background and Purpose

—

Selective serotonin reuptake inhibitors (SSRIs) have been associated with increased risk of bleeding complications, possibly as a result of inhibition of platelet aggregation. Little is known about the risk of intracerebral hemorrhage in users of SSRIs and whether the effect on platelet aggregation reduces the risk of ischemic stroke. We used population-based data to estimate the risk of hemorrhagic and ischemic stroke in users of SSRIs.

Methods

—

We performed a nested case-control study in Funen County (465 000 inhabitants), Denmark. All patients with a first-ever stroke discharge diagnosis in the period of 1994 to 1999 were identified, and a validated diagnosis of stroke was reached in 4765 cases. In all, 40 000 controls were randomly selected from the background population. Information on drug use for cases and controls was retrieved from a prescription registry with full coverage of the county. Odds ratios were adjusted for age, sex, calendar year, and use of other medication. To evaluate the effect of various potential confounders not recorded in the register data, we performed separate analyses on data from 2 large population-based surveys with more detailed information on risk factors.

Results

—

Of 659 patients with hemorrhagic stroke, 21 were current users of SSRIs. The adjusted odds ratio of hemorrhagic stroke in current SSRI users compared with never users was 1.0 [95% confidence interval (CI), 0.6 to 1.6]. Of 2717 patients with ischemic stroke, 100 were current users of SSRIs, and the adjusted odds ratio of ischemic stroke in cases compared with controls was 1.1 (95% CI, 0.9 to 1.4). The survey data indicated that additional confounder control would not have led to an increase in the relative risk estimates.

Conclusions

—

Current exposure to SSRIs is not associated with increased risk of intracerebral hemorrhage and is probably not associated with a decreased risk of ischemic stroke.
Entropy and Stability in Painting: An Information Approach to the Mechanisms of Artistic Creativity
Authors: Petrov Vladimir M.
Published: July 2002

The author presents a method for identifying the sequence of stages of the creative process in painting, specifically an artist's decisions about such parameters as genre, composition, color structure, etc. The method is based on the calculation of the coefficients of informativity relating to the distribution (and hence, entropy) of the artist's works over the above parameters. Using this method, 240 paintings by three famous Russian artists (Pavel
Computer Stereographics: The Coalescence of Virtual Space and Artistic Expression
Authors: Sorensen Vibeke , Russett Robert
Published: July 2002

Vibeke Sorensen describes her technical approach to computer stereographics and discusses in detail the actual genesis of several specific projects. She also discusses the history and future of spatial imaging, including its potential for challenging the centuries-old domination of twodimensional pictorial expression. Sorensen concludes her remarks on a cautionary note, stressing the need to place at least as much emphasis on the exploration of personal ideas and feelings as on the development of new hardware and computational processes. Robert Russett provides an introduction and background to Sorensen's life and work.
Beyond Asian American Jazz: My Musical and Political Changes in the Asian American Movement
Authors: Ho Fred
Published: July 2002

The author addresses the interconnection between making revolutionary Asian American music and the conditions for its development as contextualized by the ideological and political orientation from the Movement and its organizations. He discusses his own musical and political development as a leading revolutionary Chinese/Asian American artist.
Independence: An Intercultural Experience in North America
Authors: Privett Ray
Published: July 2002

Fourth Fest in Duluth, Minnesota, is not only about patriotism, upper-Midwest style, but a site for some criticism coming from Ojibwe Native Peoples.
Between Desktop and Head Immersion: Functional Visual Field During Vehicle Control and Navigation in Virtual Environments
Authors: Péruch Patrick , Mestre Daniel
Published: July 2002

The effects of available visual information in the periphery (enlargement of the functional visual field) on performance in navigation were evaluated in an experimental setup searching for a “compromise” between desktop and head-immersion situations. A Fixed Vision condition (fixed display) and two Mobile Vision conditions (head-tracking with a visual field of variable width) were compared in six virtual environments of different complexity and in four successive sessions. First, a global improvement in performance throughout the sessions revealed a gradual integration of the properties of the simulation device. Second, performance was higher in the Mobile Vision conditions, as shown by the smoothness of the subjects' paths (sharp curves could be negotiated without stopping), indicating the importance of a wide functional visual field. In conclusion, the need to design realistic and functionaly efficient human-machine interfaces for navigation is discussed.
War and Peace in the Strategy of the Communist Party of Greece, 1945–1949
Authors: Sfikas Thanasis D.
Published: July 2002

Using archival sources that only recently have become available, this article fo-cuses on the interplay between the concepts of war and peace in the strategy of the Communist Party of Greece (KKE) during the Greek Civil War of the late 1940s. The article demonstrates that the choices facing the KKE and its opponents changed quite dramatically in the period from 1945 to 1949. The active role of Great Britain in Greek domestic affairs and the relatively limited role of the Soviet nion meant that the KKE was increasingly ostracized in the international community. The unwillingness of the Greek Liberal Party to forge a political alliance with the KKE prompted the Communists to resume their armed struggle for power. This article presents the alternatives facing the KKE in light of the postwar domestic and international contexts.
The Tort of Injury and Dissolution of Marriage at the Wife's Initiative in Egyptian Mahkamat al-Naqd Rulings
Authors: Naveh Immanuel
Published: July 2002

In this essay, I examine the application of the codified sharī‘ a in Egyptian civil courts, drawing on the records of the Mahkamat al-Naqd from 1982. My examination is limited to the dissolution of marriage at the wife's initiative on the ground of injury (darar) caused to her by her husband. I have chosen to analyze this cause of action because of its shar‘ ī origins in Mālikī doctrine and its extensive treatment in parliamentary legislation, and because it exemplifies the broad judicial discretion used by Egyptian judges in the national courts, in their efforts to harmonize shar‘ ī and civil norms. By analyzing the Mālikī rules pertaining to the dissolution of marriage and the status of circumstantial evidence, as applied in the rulings of Mahkamat al-Naqd, I attempt to shed light on the judicial outlook of Egyptian judges with regard to both substantial and evidential questions.
ASCETICS AND AESTHETICS IN THE ANALECTS
Authors: Richey Jeffrey
Published: July 2002

The ancient Confucian Analects (Lunyu) often has been interpreted as nothing more than the "pure" ethical teachings of a humanistic Chinese sage, "Confucius" (Kongzi or Kong Qiu). A careful and historically-sensitive interpretation of the Lunyu reveals that the text is capable of resisting this reading, providing clues to an altogether different Confucius - not the storied pedant who dispenses common-sense wisdom to office-seeking disciples, but a spiritual teacher who guides his pupils toward sagehood through a combination of ascetic and aesthetic disciplines. Key references in the text to material privation, music and dance, and the exemplary disciple Yan Hui reveal how one fifth-century BCE Confucian (Ru) sect sought to preserve and construct a memory of the "historical Confucius" as a Master who instructed his disciples in ascetic disciplines, linking them to aesthetic techniques of ecstasy, and celebrated one disciple in particular, Yan Hui, as the living embodiment of his esoteric Way. Instead of proposing either a traditional, harmonizing hermeneutic of the text, or a demythologization which might reveal the "real" or "historical" Confucius and his followers, this essay argues for the toleration of multiple, even mutually-contradicting voices in this classic of ancient Chinese spirituality. A primary goal for future research on the text should be the examination of conflicts of interpretation among early Confucian sects competing to safeguard the Master's legacy.
DER PROPHET ALS FÜRBITTER: ZUM LITERARHISTORISCHEN ORT DER AMOS-VISIONEN
Authors: Becker Uwe
Published: July 2002

In der Frage, wie sich die Fürbitter-Tätigkeit eines Jesaja, Jeremia oder Amos zur Gerichtsverkündigung dieser Propheten verhält, spielen die Amos-Visionen eine Schlüsselrolle, weil hier der Weg vom Fürbitter zum Unheilspropheten gleichsam abgeschritten wird. Eine Neuuntersuchung der ursprünglich 4 Visionen (Am. vii 1-8; viii 1-2) zeigt, daß die einzelnen Szenen nicht isoliert je für sich gelesen und interpretiert werden dürfen. Vielmehr handelt es sich bei ihnen um einen literarisch einheitlich konzipierten, von vornherein auf viii 2 ausgerichteten Zyklus, der auf theologische Leittexte der Urgeschichte und die Plagenüberlieferung zurückgreift und das sich anbahnende Ende Israels als partielle Rücknahme der Schöpfung interpretiert. Insofern kann man von einer dramatisch inszenierten theologischen Reflexion sprechen (vgl. Gen. xviii 22-33), die der bleibenden Unbußfertigkeit des Volkes die (fast) unausschöpfliche Langmut Gottes entgegenstellt. Der Zyklus läßt sich darüber hinaus als literarische Fortführung und Exegese der Kernsammlung des Amos-Buches (Am. iii-vi), vielleicht auch schon von Teilen des Hosea-Buches lesen, womit sich u.a. das Fehlen der Schuldthematik in den Visionen selbst zwanglos erklärt. Literargeschichtlich sind die Visionen nicht vor der (früh-)nachexilischen Zeit anzusetzen.
Chondrocranium and visceral skeleton of Atelopus tricolor and Atelophryniscus chrysophorus tadpoles (Anura, Bufonidae)
Authors: De Sá Rafael , Lavilla E.O.
Published: July 2002

Atelopus tricolor and Atelophryniscus chrysophorus have gastromyzophorous tadpoles. Aside from specific differences, the larval chondrocrania and visceral skeletons show several shared character states, including an almost quadrangular, open chondrocranium, cornua trabeculae with expanded tips, cartilago suprarostralis as a single element, a posteriorly projected arcus subocularis quadrati, a closed muscular tunnel, and a simplified branchial basket, with only three pairs of ceratobranchiales. They are compared with diverse character states of suctorial larvae considering them as causally related to the stream life adaptations. Atelopus tricolor y Atelophryniscus chrysophorus poseen larvas gastromizóforas. Dejando de lado las diferencias específicas, los condrocráneos y esqueletos hiobranquiales larvales comparten diversos estados de carácter, incluyendo el condrocráneo cuadrangular y abierto, los cuernos trabeculares con extremos expandidos, el cartílago suprarostral como elemento único, el arco subocular proyectado hacia atrás, el túnel muscular cerrado y la cestilla branquial simplificada, con sólo tres pares de ceratobranquiales. Algunos de estos estados de carácter son comparados con aquellos de larvas suctoras considerados como causalmente relacionados a los hábitats torrentícolas, para una mejor comprensión de de la vida en ambientes de corriente rápida.