bluuebunny/crossref_metadata_2025 huggingface dataset:
L
3
—towards an open learning environment
Authors: Leidig Torsten
Published: July 2002

This article describe the use of dedicated ontology for teaching in the context of the
L
3
project, a national joint project for deploying further vocational education in Germany. The requirements for the open
L
3
learning infrastructure are presented in order to motivate our approach to metamodeling learning resources and services by using dedicated ontolgies of pedagogics and didactics. The basic concepts and parts of the pedagogical ontology are outlined, and the practical implications for several of today's problems such as authoring and design, retrieval and adaptive of training resources are illustrated. An overview of the
L
3
runtime architecture shows how the didactical ontology is used to deliver adaptive learning.
Probabilistic logic programming with conditional constraints
Authors: Lukasiewicz Thomas
Published: July 2002

We introduce a new approach to probabilistic logic programming in which probabilities are defined over a set of possible worlds. More precisely, classical program clauses are extended by a subinterval of [0,1] that describes a range for the conditional probability of the head of a clause given its body. We then analyze the complexity of selected probabilistic logic programming tasks. It turns out that probabilistic logic programming is computationally more complex than classical logic programming, More precisely, the tractability of special cases of classical logic programming generally does not carry over to the corresponding special cases of probabilistic logic programming. Moreover, we also draw a precise picture of the complexity of deciding and computing tight logical consequences in probabilistic reasoning with conditional constraints in general. We then present linear optimization techniques for deciding satisfiability and computing tight logical consequencesof probabilistic logic programs. These techniques are efficient in the special case in which we have little relevant purely probabilistic knowledge. We finally show that probabilistic logic programming under certain syntactic and semantic restrictions is closely related to van Emden's quantitative deduction, and thus has computational properties similar to calssical logic programming. Based on this result, we present an efficient approximation technique for probabilistic logic programming.
Characterizing the scalability of a large web-based shopping system
Authors: Arlitt Martin , Krishnamurthy Diwakar , Rolia Jerry
Published: July 2002

This article presents an analysis of five days of workload data from a large Web-based shopping system. The multitier environment of this Web-based shopping system includes Web servers, application servers, database servers, and an assortment of load-balancing and firewall appliances. We characterize user requests and sessions and determine their impact on system performance scalability. The purpose of our study is to assess scalability and support capacity planning exercises for the multitier system. We find that horizontal scalability is not always an adequate mechanism for supporting increased workloads and that personalization and robots can have a significant impact on system scalability.
Algorithm 812: BPOLY
Authors: Tsai Yi-Feng , Farouki Rida T.
Published: July 2002

The design, implementation, and testing of a C++ software library for univriate polynomials in Bernstein form is described. By invoking the class environment and operator overloading, each polynomial in an expression is interpreted as an object compatible with the arithmetic operations and other common functions (subdivision, degree, elevation, differentiation and integration, compoistion, greatest common divisor, real-root solving, etc.) for polynomials in Bernstein form. The library allows compact and intuitive implementation of lengthy manipulation of Bernstein-form polynomials, which often arise in computer graphics and computer-aided design and manufacturing applications. A series of empirical tests indicates that the library functions are typically very accurate and reliable, even for polynomials of surprisingly high degree.
Markov chains and computer aided geometric design: Part II—examples and subdivision matrices
Authors: Goldman Ronald N.
Published: July 2002

In Part I, Markov chains were shown to be associated with solutions to several standard problems in computer-aided geometric design. Constraints on these Markov chains were also derived. Examples are given here of Markov chains that either satisfy some of these constraints or solve one of these problems. Subdivision matrices are also studied in special detail.
Hypertext and the Oxford English dictionary
Authors: Raymond Darrell,R. , Tompa Frank,WM.
Published: July 2002

Hypertext databases can be produced by converting existing text documents to electronic form. The basic task in conversion is identification of fragments. We illustrate that this is not always a straightforward process with an analysis of the Oxford English Dictionary.
How do I loaf here? let me count the ways
Authors: Lim Vivien K. G. , Teo Thompson S. H. , Loo Geok Leng
Published: July 2002

Cyberloafing in an Asian context.
Does electronic monitoring of employee internet usage work?
Authors: Urbaczewski Andrew , Jessup Leonard M.
Published: July 2002

Using a controlled setting to study the effects of monitoring.
Conceptual models
Authors: Johnson Jeff , Henderson Austin
Published: July 2002

Suppose you are designing a software product, electronic appliance, or Web service. You've gathered functional requirements from Marketing and from prospective customers and users. You've done a task-analysis and created user profiles. What's your next step?
Achieving extensibility through product-lines and domain-specific languages
Authors: Batory Don , Johnson Clay , MacDonald Bob , von Heeder Dale
Published: July 2002

This is a case study in the use of
product-line architectures (PLAs)
and
domain-specific languages (DSLs)
to design an extensible command-and-control simulator for Army fire support. The reusable components of our PLA are layers or "aspects" whose addition or removal simultaneously impacts the source code of multiple objects in multiple, distributed programs. The complexity of our component specifications is substantially reduced by using a DSL for defining and refining state machines, abstractions that are fundamental to simulators. We present preliminary results that show how our PLA and DSL synergistically produce a more flexible way of implementing state-machine-based simulators than is possible with a pure Java implementation.
A semantic approach to visualizing online conversations
Authors: Donath Judith
Published: July 2002

Visualizing patterns in online conversations give participants a better grasp of their cyber environment and their fellow inhabitants.
Productivity enhancement from computer-mediated communication: a systems contingency approach
Authors: Hiltz Starr Roxanne
Published: July 2002

A systems contingency approach to social impacts of computing predicts that productivity enhancement will be a function of a complex interaction of social and technical systems.
A language for music printing
Authors: Gourlay John S.
Published: July 2002

A music-description language designed to facilitate both electronic communication and publication-quality printing of musical scores incorporates a syntax for expressing concurrency and two-dimensionality and places new demands on text formatters.
Computer anxiety in management: myth or reality?
Authors: Howard Geoffry S. , Smith Robert D.
Published: July 2002

Although many informal surveys in the business press have contended that computer anxiety has a significant adverse impact on managers' willingness to use microcomputers, the problem is neither as extensive nor as severe as once believed.
Introduction to special section on software testing
Authors: Hamlet R.
Published: July 2002

The field of software testing spans mathematical theory, the art and practice of validation, and methodology of software development. To cover this range would require a textbook (or several texts), not a trio of articles. But the work presented in this special section
is
a kind of "test set." Each paper is a significant contribution within one of the three broad areas. The reader must now make the assessment that is critical to any review of test points: are they representative? My own answer is 'no'; these articles are provocative and revealing rather than routine summaries. And perhaps that is what software testing is all about: good tests are the ones that provide new insights, not the ones that cover well worn ground.
The growth of software testing
Authors: Gelperin D. , Hetzel B.
Published: July 2002

We can trace the evolution of software test engineering by examining changes in the testing process model and the level of professionalism over the years. The current definition of a good software testing practice involves some preventive methodology.
A generalized model management system for mathematical programming
Authors: Dolk Daniel R.
Published: July 2002

This paper examines mathematical programming software in the context of model management and decision support. The concept of a model management system (MMS) is introduced and compared to traditional modeling systems. An MMS is seen as a much more generalized software system that requires the confluence of existing operations research, database management, and artificial intelligence techniques. By incorporating powerful, abstraction-based representation structures, an MMS can support multiple levels of model abstraction, only one of which corresponds to traditional, solution-oriented modeling software. The database structures required to implement a knowledge-based MMS are discussed and a prototype system for mathematical programming, the Generalized eXperimental Math Programming system (GXMP), is described. An algebraic language developed for use in GXMP is described in detail.
Boxer: a reconstructible computational medium
Authors: diSessa A. A , Abelson H.
Published: July 2002

Programming is most often viewed as a way for experts to get computers to perform complex tasks efficiently and reliably. Boxer presents an alternative image—programming as a way for nonexperts to control a reconstructible medium, much like written language, but with dramatically extended interactive capabilities.
Microprocessor architectures: a comparison based on code generation by compiler
Authors: Wirth Niklaus
Published: July 2002

By carefully tuning computer and compiler, it is possible to avoid the otherwise inevitable compromises between complex compiling algorithms and less-than-optimal compiled code, where the key to performance appears to lie neither in sophisticated nor drastically reduced architectures, but in the key concepts of regularity and completeness.
Software errors and complexity: an empirical investigation0
Authors: Basili Victor R. , Perricone Barry T.
Published: July 2002

An analysis of the distributions and relationships derived from the change data collected during development of a medium-scale software project produces some surprising insights into the factors influencing software development. Among these are the tradeoffs between modifying an existing module as opposed to creating a new one, and the relationship between module size and error proneness.
The maximum concurrent flow problem
Authors: Shahrokhi Farhad , Matula D. W.
Published: July 2002

The maximum concurrent flow problem (MCFP) is a multicommodity flow problem in which every pair of entities can send and receive flow concurrently. The ratio of the flow supplied between a pair of entities to the predefined demand for that pair is called
throughput
and must be the same for all pairs of entities for a concurrent flow. The MCFP objective is to maximize the throughput, subject to the capacity constraints. We develop a fully polynomial-time approximation scheme for the MCFP for the case of arbitrary demands and uniform capacity. Computational results are presented. It is shown that the problem of associating costs (distances) to the edges so as to maximize the minimum-cost of routing the concurrent flow is the dual of the MCFP. A path-cut type duality theorem to expose the combinatorial structure of the MCFP is also derived. Our duality theorems are proved constructively for arbitrary demands and uniform capacity using the algorithm. Applications include packet-switched networks [1, 4, 8], and cluster analysis [16].
Interface design issues for advice-giving expert systems
Authors: Carroll John M. , McKendree Jean
Published: July 2002

Advice giving could become the first successful domain for intelligent interfaces.
Survey of closed queueing networks with blocking
Authors: Onvural Raif O.
Published: July 2002

Closed queueing networks are frequently used to model complex service systems such as production systems, communication systems, computer systems, and flexible manufacturing systems. When limitations are imposed on the queue sizes (i.e., finite queues), a phenomenon called
blocking
occurs. Queueing networks with blocking are, in general, difficult to treat. Exact closed form solutions have been reported only in a few special cases. Hence, most of the techniques that are used to analyze such queueing networks are in the form of approximations, numerical analysis, and simulation. In this paper, we give a systematic presentation of the literature related to closed queueing networks with finite queues. The results are significant for both researchers and practitioners.
A general framework for visualizing abstract objects and relations
Authors: Kamada Tomihisa , Kawai Satoru
Published: July 2002

Pictorial representations significantly enhance our ability to understand complicated relations and structures, which means that information systems strongly require user interfaces that support the visualization of many kinds of information with a wide variety of graphical forms. At present, however, these difficult visualization problems have not been solved. We present a visualization framework for translating abstract objects and relations, typically represented in textual forms, into pictorial representations, and describe a general visualization interface based on this framework. In our framework, abstract objects and relations are mapped to graphical objects and relations by user-defined mapping rules. The kernel of our visualization process is to determine a layout of graphical objects under geometric constraints. A constraint-based object layout system named COOL has been developed to handle this layout problem. COOL introduces the concept of rigidity of constraints in order to reasonably handle, a set of conflicting constraints by use of the least squares method. As applications of our system, we show the generation of kinship diagrams, list diagrams, Nassi-Shneiderman diagrams, and entity-relationship diagrams.
THE ANTHROPOLOGY OF CITIES: Imagining and Theorizing the City
Authors: Low Setha M.
Published: July 2002

▪ Abstract  This review considers the following questions: Why is the city undertheorized in anthropology? Why is an anthropological voice rarely heard in the urban studies and urban policy discourse? Anthropological literature published since 1989 is reviewed, with an emphasis on contributions to urban theory and the locating of anthropological studies within the broader context of urban studies. The city is found not to be absent in anthropological theory, but it has had no major theoretical impact. The images of the ethnic city, divided city, deindustrialized city, and global city have been most influential, as has research in the areas of racism, migration, poststructural studies of conflict and resistance, and critiques of architecture and urban planning. The literature continues to focus on the links between the experience of individuals and sociopolitical and economic processes as well as on the cultural meaning of the urban environment. The newest areas of inquiry include the study of urban space and time, metropolitan knowledge, and ethnoaesthetics.
Discourse and Racism: European Perspectives
Authors: Wodak R. , Reisigl M.
Published: July 2002

▪ Abstract  This paper provides an overview of the main approaches to the discursive analysis of racist utterances. Moreover, we discuss the notions of racism and race historically and from the point of view of different cultures and languages. We restrict ourselves to the discourse analytical concepts and methodologies, which vary greatly, both in theory and in analysis. We present one example and analyze it in detail as an illustration of the linguistic tools that help make hidden and latent meanings transparent.
Archaeology, Property, and Prehistory
Authors: Earle Timothy
Published: July 2002

▪ Abstract  Property determines exclusive rights to things. It is a key theoretical concept in the social sciences and a material reality in human societies. Since the defining work of Lewis Henry Morgan, property has been studied by anthropologists interested in human economies, societies, and social evolution. Cross-cultural studies suggest systematic associations of contrasting property rights with particular characteristics of social institutions and resource developments. From the works of Childe, Adams, and Renfrew, archaeologists have considered property as related to ecological concepts of territoriality and to Marxist concepts of control and alienation. Techniques to study property archaeologically included patterns of labor investment, warfare, settlement distributions, and physical marking. Although each technique is open to alternative interpretations, combining the techniques provides a robust description of property regimes in prehistory.
CYTOSKELETALPERSPECTIVES ONROOTGROWTH ANDMORPHOGENESIS
Authors: Barlow Peter W. , Baluška František
Published: July 2002

▪ Abstract  Growth and development of all plant cells and organs relies on a fully functional cytoskeleton comprised principally of microtubules and microfilaments. These two polymeric macromolecules, because of their location within the cell, confer structure upon, and convey information to, the peripheral regions of the cytoplasm where much of cellular growth is controlled and the formation of cellular identity takes place. Other ancillary molecules, such as motor proteins, are also important in assisting the cytoskeleton to participate in this front-line work of cellular development.

Roots provide not only a ready source of cells for fundamental analyses of the cytoskeleton, but the formative zone at their apices also provides a locale whereby experimental studies can be made of how the cytoskeleton permits cells to communicate between themselves and to cooperate with growth-regulating information supplied from the apoplasm.
Physical Conditions in Regions of Star Formation
Authors: Evans II Neal J.
Published: July 2002

▪ Abstract  The physical conditions in molecular clouds control the nature and rate of star formation, with consequences for planet formation and galaxy evolution. The focus of this review is on the conditions that characterize regions of star formation in our Galaxy. A review of the tools and tracers for probing physical conditions includes summaries of generally applicable results. Further discussion distinguishes between the formation of low-mass stars in relative isolation and formation in a clustered environment. Evolutionary scenarios and theoretical predictions are more developed for isolated star formation, and observational tests are beginning to interact strongly with the theory. Observers have identified dense cores collapsing to form individual stars or binaries, and analysis of some of these cores support theoretical models of collapse. Stars of both low and high mass form in clustered environments, but massive stars form almost exclusively in clusters. The theoretical understanding of such regions is considerably less developed, but observations are providing the ground rules within which theory must operate. The richest and most massive star clusters form in massive, dense, turbulent cores, which provide models for star formation in other galaxies.
Transcription Elongation and Human Disease
Authors: Conaway Joan Weliky , Conaway Ronald C.
Published: July 2002

▪ Abstract  Eukaryotic mRNA synthesis is catalyzed by multisubunit RNA polymerase II and proceeds through multiple stages referred to as preinitiation, initiation, elongation, and termination. Over the past 20 years, biochemical studies of eukaryotic mRNA synthesis have largely focused on the preinitiation and initiation stages of transcription. These studies led to the discovery of the class of general initiation factors (TFIIB, TFIID, TFIIE, TFIIF, and TFIIH), which function in intimate association with RNA polymerase II and are required for selective binding of polymerase to its promoters, formation of the open complex, and synthesis of the first few phosphodiester bonds of nascent transcripts. Recently, biochemical studies of the elongation stage of eukaryotic mRNA synthesis have led to the discovery of several cellular proteins that have properties expected of general elongation factors and that have been found to play unanticipated roles in human disease. Among these candidate general elongation factors are the positive transcription elongation factor b (P-TEFb), eleven-nineteen lysine-rich in leukemia (ELL), Cockayne syndrome complementation group B (CSB), and elongin proteins, which all function in vitro to expedite elongation by RNA polymerase II by suppressing transient pausing or premature arrest by polymerase through direct interactions with the elongation complex. Despite their similar activities in elongation, the P-TEFb, ELL, CSB, and elongin proteins appear to play roles in a diverse collection of human diseases, including human immunodeficiency virus-1 infection, acute myeloid leukemia, Cockayne syndrome, and the familial cancer predisposition syndrome von Hippel-Lindau disease. Here we review our current understanding of the P-TEFb, ELL, CSB, and elongin proteins, their mechanisms of action, and their roles in human disease.
Metabolic Engineering
Authors: Koffas M. , Roberge C. , Lee K. , Stephanopoulos G.
Published: July 2002

▪ Abstract  Metabolic engineering is the science that combines systematic analysis of metabolic and other pathways with molecular biological techniques to improve cellular properties by designing and implementing rational genetic modifications. As such, metabolic engineering deals with the measurement of metabolic fluxes and elucidation of their control as determinants of metabolic function and cell physiology. A novel aspect of metabolic engineering is that it departs from the traditional reductionist paradigm of cellular metabolism, taking instead a holistic view. In this sense, metabolic engineering is well suited as a framework for the analysis of genome-wide differential gene expression data, in combination with data on protein content and in vivo metabolic fluxes. The insights of the integrated view of metabolism generated by metabolic engineering will have profound implications in biotechnological applications, as well as in devising rational strategies for target selection for screening candidate drugs or designing gene therapies. In this article we review basic concepts of metabolic engineering and provide examples of applications in the production of primary and secondary metabolites, improving cellular properties, and biomedical engineering.
Electrophysiological Modeling of Cardiac Ventricular Function: From Cell to Organ
Authors: Winslow R. L. , Scollan D. F. , Holmes A. , Yung C. K. , Zhang J. , Jafri M. S.
Published: July 2002

▪ Abstract  Three topics of importance to modeling the integrative function of the heart are reviewed. The first is modeling of the ventricular myocyte. Emphasis is placed on excitation-contraction coupling and intracellular Ca2+ handling, and the interpretation of experimental data regarding interval-force relationships. Second, data on use of diffusion tensor magnetic resonance (DTMR) imaging for measuring the anatomical structure of the cardiac ventricles are presented. A method for the semi-automated reconstruction of the ventricles using a combination of gradient recalled acquisition in the steady state (GRASS) and DTMR images is described. Third, we describe how these anatomically and biophysically based models of the cardiac ventricles can be implemented on parallel computers.
EUKARYOTIC TRANSCRIPTION FACTOR-DNA COMPLEXES
Authors: Patikoglou G. , Burley S. K.
Published: July 2002

▪ Abstract  Eukaryotes have three distinct RNA polymerases that catalyze transcription of nuclear genes. RNA polymerase II is responsible for transcribing nuclear genes encoding the messenger RNAs and several small nuclear RNAs. Like RNA polymerases I and III, polymerase II cannot recognize its target promoter directly and initiate transcription without accessory factors. Instead, this large multisubunit enzyme relies on general transcription factors and transcriptional activators and coactivators to regulate transcription from class II promoters. X-ray crystallography and nuclear magnetic resonance spectroscopy have been used to study complexes of general transcription factors and transcriptional activators with their specific DNA targets. This work has provided important structural insights into transcription initiation by polymerase II and the more general problem of DNA sequence recognition.
NITROXIDE SPIN-SPIN INTERACTIONS: Applications to Protein Structure and Dynamics
Authors: Hustedt Eric J. , Beth Albert H.
Published: July 2002

▪ Abstract  Measurement of the distance between two spin label probes in proteins permits the spatial orientation of elements of defined secondary structure. By using site-directed spin labeling, it is possible to determine multiple distance constraints and thereby build tertiary and quaternary structural models as well as measure the kinetics of structural changes. New analytical methods for determining interprobe distances and relative orientations for uniquely oriented spin labels have been developed using global analysis of multifrequency electron paramagnetic resonance data. New methods have also been developed for determining interprobe distances for randomly oriented spin labels. These methods are being applied to a wide range of structural problems, including peptides, soluble proteins, and membrane proteins, that are not readily characterized by other structural techniques.
CLOSING IN ON BACTERIORHODOPSIN: Progress in Understanding the Molecule
Authors: Haupts Ulrich , Tittor Jörg , Oesterhelt Dieter
Published: July 2002

▪ Abstract  Bacteriorhodopsin is the best understood ion transport protein and has become a paradigm for membrane proteins in general and transporters in particular. Models up to 2.5 Å resolution of bacteriorhodopsin's structure have been published during the last three years and are basic for understanding its function. Thus one focus of this review is to summarize and to compare these models in detail. Another focus is to follow the protein through its catalytic cycle in summarizing more recent developments. We focus on literature published since 1995; a comprehensive series of reviews was published in 1995 ( 112 ).
Evolutionary Physiology
Authors: Feder Martin E. , Bennett Albert F. , Huey Raymond B.
Published: July 2002

▪ Abstract  Evolutionary physiology represents an explicit fusion of two complementary approaches: evolution and physiology. Stimulated by four major intellectual and methodological developments (explicit consideration of diverse evolutionary mechanisms, phylogenetic approaches, incorporation of the perspectives and tools of evolutionary genetics and selection studies, and generalization of molecular techniques to exotic organisms), this field achieved prominence during the past decade. It addresses three major questions regarding physiological evolution: (a) What are the historical, ecological, and phylogenetic patterns of physiological evolution? (b) How important are and were each of the known evolutionary processes (natural selection, sexual selection, drift, constraint, genetic coupling/hitchhiking, and others) in engendering or limiting physiological evolution? and (c) How do the genotype, phenotype, physiological performance, and fitness interact in influencing one another's future values? To answer these questions, evolutionary physiology examines extant and historical variation and diversity, standing genetic and phenotypic variability in populations, and past and ongoing natural selection in the wild. Also, it manipulates genotypes, phenotypes, and environments of evolving populations in the laboratory and field. Thus, evolutionary physiology represents the infusion of paradigms, techniques, and approaches of evolutionary biology, genetics, and systematics into physiology. The reciprocal infusion of physiological approaches into evolutionary biology and systematics can likewise have great value and is a future goal.

…each level [of biological integration] offers unique problems and insights, and….each level finds its explanations of mechanism in the levels below, and its significance in the levels above. George A. Bartholomew ( 7 , p. 8)
ENVIRONMENTAL LIFE-CYCLE COMPARISONS OF RECYCLING, LANDFILLING, AND INCINERATION: A Review of Recent Studies
Authors: Denison Richard A.
Published: July 2002

▪ Abstract  This paper reviews and analyzes the major recent North American studies that have compared on an environmental basis the major options used to manage the materials that comprise municipal solid waste (MSW). The reviewed studies provide quantitative comparative information on one or more of the following environmental parameters: solid waste output, energy use, and releases of pollutants to the air and water. The review finds that all of the studies support the following conclusions: Systems based on recycled production plus recycling offer substantial system-wide or “life-cycle” environmental advantages over systems based on virgin production plus either incineration or landfilling, across all four parameters examined. Only when the material recovery or waste management activities are analyzed in isolation—which does not account for the system-wide consequences of choosing one system option over another—do the virgin material–based systems appear to offer advantages over recycled production plus recycling.
PUBLIC HEALTH IMPACT OF AIR POLLUTION AND IMPLICATIONS FOR THE ENERGY SYSTEM
Authors: Rabl Ari , Spadaro Joseph V.
Published: July 2002

▪ Abstract  Low environmental damage is one of the main justifications for continued efforts to reduce energy consumption and to shift to cleaner sources such as solar energy, especially now that supply security has slipped from public consciousness. In recent years there has been much progress in the analysis of environmental damages, in particular thanks to the ExternE (External Costs of Energy) Project of the European Commission. This paper presents a summary of the methodology and key results for the external costs of the major energy technologies. Even though the uncertainties are large, the results provide substantial evidence that the classic air pollutants (particles, NOx and SOx) from fossil fuels impose significant public health costs, comparable to the cost of global warming from CO2 emissions.
GENETIC DISSECTION OF SEXUAL BEHAVIOR IN DROSOPHILA MELANOGASTER
Authors: Yamamoto Daisuke , Jallon Jean-Marc , Komatsu Akira
Published: July 2002

▪ Abstract  Mating of Drosophila melanogaster is a stereotypically patterned behavior consisting of a fixed sequence of actions that are primarily under genetic control. Mutations that disrupt specific aspects of mating activities offer a starting point for exploring the molecular machineries underlying sexual behavior. Several genes, identified as causing aberrant sexual behavior when mutated, have been isolated and cloned, providing molecular probes for expression and mosaic analyses that can be used in specifying the cells responsible for the behavior. This review presents current understandings of mating behavior obtained by such molecular and cellular approaches and provides an overview of future directions of research in behavioral genetics.
REPRODUCTIVE CASTE DETERMINATION IN EUSOCIAL WASPS (HYMENOPTERA: VESPIDAE)
Authors: O'Donnell Sean
Published: July 2002

▪ Abstract  Wasps (Vespidae) exhibit a range of social complexity, from solitary living to eusocial colonies, and thus are exemplary for studies of the evolutionary origin and maintenance of social behavior in animals. Integral to the definition of eusociality is the presence of reproductive castes, group members that differ qualitatively in their ability to reproduce in a social setting. Behavioral and morphological evidence suggests that caste determination, the developmental process by which differences in fecundity are established, occurs to a large extent before adult emergence (pre-imaginally) in many species of Vespidae, in both basal and advanced taxa within the clade (Vespinae + Polistinae), which includes most eusocial species. Pre-imaginal determination has been documented in many taxa (e.g. independent-founding Polistinae) where it was not thought to occur. Correlative and experimental studies indicate that differences in nutrition during larval development are often the basis of pre-imaginal caste determination. Pre-imaginal caste determination has important implications for the roles of subfertility and manipulation by nest mates in the evolution of eusocial behavior.
EVOLUTION AND ECOLOGY OF SPIDER COLORATION
Authors: Oxford G. S. , Gillespie R. G.
Published: July 2002

▪ Abstract  Genetic color variation provides a tangible link between the external phenotype of an organism and its underlying genetic determination and thus furnishes a tractable system with which to explore fundamental evolutionary phenomena. Here we examine the basis of color variation in spiders and its evolutionary and ecological implications. Reversible color changes, resulting from several mechanisms, are surprisingly widespread in the group and must be distinguished from true genetic variation for color to be used as an evolutionary tool. Genetic polymorphism occurs in a large number of families and is frequently sex limited: Sex linkage has not yet been demonstrated, nor have the forces promoting sex limitation been elucidated. It is argued that the production of color is metabolically costly and is principally maintained by the action of sight-hunting predators. Key avenues for future research are suggested.
COMPUTING AERODYNAMICALLY GENERATED NOISE
Authors: Wells Valana L. , Renaut Rosemary A.
Published: July 2002

▪ Abstract  In contrast to computational aerodynamics, which has advanced to a fairly mature state, computational aeroacoustics (CAA) has only recently emerged as a separate area of study. Following a discussion of the classical field of aeroacoustics as introduced by Lighthill, the paper provides an overview and analysis of the problems associated with utilizing standard computational aerodynamics procedures for acoustic computations. Numerical aspects of computing sound-wave propagation are considered, including assessments of several schemes for spatial and temporal differencing. Issues of particular concern in computing aerodynamically generated noise, such as implementing surface and radiation boundary conditions and algorithms for predicting nonlinear steepening and shocks, are discussed. In addition, the paper briefly reviews alternatives to the conventional finite-difference schemes, such as boundary-element and spectral methods and the uncommon lattice-gas method.
NONLINEAR BUBBLE DYNAMICS
Authors: Feng Z. C. , Leal L. G.
Published: July 2002

▪ Abstract  The inertia-dominated dynamics of a single gas or vapor bubble in an incompressible or nearly incompressible liquid has been the subject of intense investigation for many years. Studies prior to 1976 were thoroughly reviewed by Plesset & Prosperetti (1977) in Volume 9 of this series. Our review fills the gap between Plesset & Prosperetti's review and the present. We focus on new understandings of bubble dynamics through a nonlinear dynamical systems approach.
REGULATION OF SYMBIOTIC ROOT NODULE DEVELOPMENT
Authors: Schultze M. , Kondorosi A.
Published: July 2002

▪ Abstract  Symbiosis between rhizobia and leguminous plants leads to the formation of N2-fixing root nodules. The interaction of rhizobia and plants shows a high degree of host specificity based on the exchange of chemical signals between the symbiotic partners. The plant signals, flavonoids exuded by the roots, activate the expression of nodulation genes, resulting in the production of the rhizobial lipochitooligosaccharide signals (Nod factors). Nod factors act as morphogens that, under conditions of nitrogen limitation, induce cells within the root cortex to divide and to develop into nodule primordia. This review focuses on how the production of Nod factors is regulated, how these signals are perceived and transduced by the plant root, and the physiological conditions and plant factors that control the early events leading to root nodule development.
Bacterial Cell Division
Authors: Rothfield L , Justice S , García-Lara J
Published: July 2002

▪ Abstract  Formation of the bacterial division septum is catalyzed by a number of essential proteins that assemble into a ring structure at the future division site. Assembly of proteins into the cytokinetic ring appears to occur in a hierarchial order that is initiated by the FtsZ protein, a structural and functional analog of eukaryotic tubulins.

Placement of the division site at its correct location in Escherichia coli requires a division inhibitor (MinC), that is responsible for preventing septation at unwanted sites near the cell poles, and a topological specificity protein (MinE), that forms a ring at midcell and protects the midcell site from the division inhibitor. However, the mechanism responsible for identifying the position of the midcell site or the polar sites used for spore septum formation is still unclear.

Regulation of the division process and its coordination with other cell cycle events, such as chromosome replication, are poorly understood. However, a protein has been identified in Caulobacter (CtrA) that regulates both the initiation of chromosome regulation and the transcription of ftsZ, and that may play an important role in the coordination process.
Molecular Genetics of Human Retinal Disease
Authors: Rattner Amir , Sun Hui , Nathans Jeremy
Published: July 2002

▪ Abstract  The past decade has witnessed extraordinary progress in retinal disease gene identification, the analysis of animal and tissue culture models of disease processes, and the integration of this information with clinical observations and with retinal biochemistry and physiology. During this period over twenty retinal disease genes were identified and for many of these genes there are now significant insights into their role in disease. This review presents an overview of the basic and clinical biology of the retina, summarizes recent progress in understanding the molecular mechanisms of inherited retinal diseases, and offers an assessment of the role that genetics will play in the next phase of research in this area.
DYNAMIC LOCALIZATION OF BACTERIAL AND PLASMID CHROMOSOMES
Authors: Hiraga Sota
Published: July 2002

▪ Abstract  Plasmid-encoded partition genes determine the dynamic localization of plasmid molecules from the mid-cell position to the 1/4 and 3/4 positions. Similarly, bacterial homologs of the plasmid genes participate in controlling the bidirectional migration of the replication origin (oriC) regions during sporulation and vegetative growth in Bacillus subtilis, but not in Escherichia coli. In E. coli, but not B. subtilis, the chromosomal DNA is fully methylated by DNA adenine methyltransferase. The E. coli SeqA protein, which binds preferentially to hemimethylated nascent DNA strands, exists as discrete foci in vivo. A single SeqA focus, which is a SeqA-hemimethylated DNA cluster, splits into two foci that then abruptly migrate bidirectionally to the 1/4 and 3/4 positions during replication. Replicated oriC copies are linked to each other for a substantial period of generation time, before separating from each other and migrating in opposite directions. The MukFEB complex of E. coli and Smc of B. subtilis appear to participate in the reorganization of bacterial sister chromosomes.
ENU Mutagenesis: Analyzing Gene Function in Mice
Authors: Balling Rudi
Published: July 2002

With the completion of the human genome, sequence analysis of gene function will move into the center of future genome research. One of the key strategies for studying gene function involves the genetic dissection of biological processes in animal models. Mouse mutants are of particular importance for the analysis of disease pathogenesis and transgenic techniques, and gene targeting have become routine tools. Recently, phenotype-driven strategies using chemical mutagenesis have been the target of increasing interest. In this review, the current state of ENU mutagenesis and its application as a systematic tool of genome analysis are examined.
The Human Repertoire of Odorant Receptor Genes and Pseudogenes
Authors: Mombaerts Peter
Published: July 2002

The nose of Homo sapiens is a sophisticated chemical sensor. It is able to smell almost any type of volatile molecule, often at extraordinarly low concentrations, and can make fine perceptual discriminations between structurally related molecules. The diversity of odor recognition is mediated by odorant receptor (OR) genes, discovered in 1991 by Buck & Axel. OR genes form the largest gene families in mammalian genomes. A decade after their discovery, advances in the sequencing of the human genome have provided a first draft of the human OR repertoire: It consists of ∼1000 sequences, residing in multiple clusters spread throughout the genome, with more than half being pseudogenes. Allelic variants are beginning to be recognized and may provide an opportunity for genotype-phenotype correlations. Here, I review the current knowledge of the human OR repertoire and summarize the limited information available regarding putative pheromone and taste receptors in humans.
X-Linked Lymphoproliferative Disease: A Progressive Immunodeficiency
Authors: Morra Massimo , Howie Duncan , Grande Maria Simarro , Sayos Joan , Wang Ninghai , Wu Chengbin , Engel Pablo , Terhorst Cox
Published: July 2002

Our understanding of the X-linked lymphoproliferative syndrome (XLP) has advanced significantly in the last two years. The gene that is altered in the condition (SAP/SH2D1A) has been cloned and its protein crystal structure solved. At least two sets of target molecules for this small SH2 domain-containing protein have been identified: A family of hematopoietic cell surface receptors, i.e. the SLAM family, and a second molecule, which is a phosphorylated adapter. A SAP-like protein, EAT-2, has also been found to interact with this family of surface receptors. Several lines of evidence, including structural studies and analyses of missense mutations in XLP patients, support the notion that SAP/SH2D1A is a natural inhibitor of SH2-domain-dependent interactions with members of the SLAM family. However, details of its role in signaling mechanisms are yet to be unravelled. Further analyses of the SAP/SH2D1A gene in XLP patients have made it clear that the development of dys-gammaglobulinemia and B cell lymphoma can occur without evidence of prior EBV infection. Moreover, preliminary results of virus infections of a mouse in which the SAP/SH2D1A gene has been disrupted suggest that EBV infection is not per se critical for the development of XLP phenotypes. It appears therefore that the SAP/SH2D1A gene controls signaling via the SLAM family of surface receptors and thus may play a fundamental role in T cell and APC interactions during viral infections.
ALCOHOL IN THE ELDERLY
Authors: Dufour, M.D., M.P.H Mary , Fuller, M.D., M.S Richard K.
Published: July 2002

▪ Abstract  Although older individuals drink less and report fewer alcohol-related problems than do younger individuals, alcohol use and abuse are significant health issues for older patients. The signs and symptoms of alcohol problems and dependence in the elderly may not only differ from those of young problem drinkers, but may also be present at lower levels of alcohol consumption. Older alcoholics do well in alcohol treatment. Therefore, discussion of alcohol consumption is a critical part of every history and physical examination for all patients, including older individuals.
GLUCOCORTICOID AND MINERALOCORTICOID RECEPTORS: Biology and Clinical Relevance
Authors: Funder, MD John W.
Published: July 2002

▪ Abstract  Mineralocorticoid and glucocorticoid receptors act as homodimers via canonical pentadecamer hormone response elements to regulate transcription. Glucocorticoid, but as yet not mineralocorticoid, receptors have been shown also to modulate AP-1- and NFκB-induced transcription by direct protein-protein interactions. The role of 11β-hydroxysteroid dehydrogenase in conferring aldosterone specificity on epithelial mineralocorticoid receptors has been proven by the demonstration of sequence mutations in all cases of apparent mineralocorticoid excess examined to date. The autosomal form of aldosterone resistance (pseudohypoaldosteronism) has been shown to reflect loss-of-function mutations in epithelial sodium channel subunit sequence. (Patho)physiological roles for aldosterone and glucocorticoid membrane receptors, and for the recently described nuclear receptors for 11–ketosteroids in 11β–hydroxysteroid dehydrogenase–protected epithelia, remain to be established.
NALTREXONE IN THE TREATMENT OF ALCOHOLISM
Authors: Weinrieb, MD Robert M. , O'Brien, MD, PhD Charles P.
Published: July 2002

▪ Abstract  Alcoholism affects nearly 12.5 million Americans and is responsible for annual costs of over $130 billion from loss of job productivity, deleterious health effects, and direct treatment expenses. Research on treating alcoholism from the standpoint of relapse prevention using psychosocial interventions alone has produced only modest results. Studies on the efficacy of adjunctive medications using multiple medications in placebo-controlled and open trials combined with psychosocial interventions have shown mixed results. Recently, a safe and well-tolerated opiate antagonist, naltrexone, was approved by the Food and Drug Administration (FDA) for the adjunctive treatment of alcoholism. This review describes the pertinent preclinical and clinical research that led to the FDA's approval. Details are provided describing the subjects, methods, and results of the two pivotal human studies that led to the FDA review for this indication. Clinical therapeutic guidelines, appropriate patient selection, and future directions are also elucidated.
Idiopathic Ventricular Tachycardia
Authors: Altemose, MD Gregory T. , Buxton, MD Alfred E.
Published: July 2002

Most ventricular tachycardias encountered in clinical practice occur in patients who have structural heart disease. Idiopathic ventricular tachycardia refers to those arrhythmias that occur in patients without structural heart disease, metabolic/electrolyte abnormalities, or the long QT syndrome. Three commonly recognized forms of idiopathic ventricular tachycardia include: (a) ventricular tachycardia associated with mitral valve prolapse, (b) ventricular tachycardia originating from the right ventricular outflow tract, and (c) ventricular tachycardia originating from the left ventricle. Recently, a fourth type of idiopathic ventricular tachycardia, termed the Brugada syndrome, has been identified as responsible for some cases of cardiac arrest in persons without apparent structural heart disease. Each form of ventricular tachycardia may be considered a discrete syndrome based on its electrocardiographic characteristics, mechanisms, responses to pharmacologic intervention, and prognosis (good in most cases). Ventricular tachycardias range from the common to the exotic, but all represent syndromes with which the internist and general cardiologist should be familiar.