bluuebunny/crossref_metadata_2025 huggingface dataset:
Quasi- Newton Methods for Nonlinear Equations
Authors: Zeleznik Frank J.
Published: July 2002

A unified derivation is presented of the quasi-Newton methods for solving systems of nonlinear equations. The general algorithm contains, as special cases, all of the previously proposed quasi-Newton methods.
Indexed Grammars—An Extension of Context-Free Grammars
Authors: Aho Alfred V.
Published: July 2002

A new type of grammar for generating formal languages, called an indexed grammar, is presented. An indexed grammar is an extension of a context-free grammar, and the class of languages generated by indexed grammars has closure properties and decidability results similar to those for context-free languages. The class of languages generated by indexed grammars properly includes all context-free languages and is a proper subset of the class of context-sensitive languages. Several subclasses of indexed grammars generate interesting classes of languages.
A
-Stable Composite Multistep Methods
Authors: Sloate Harry M. , Bickart Theodore A.
Published: July 2002

Consider the set of multistep formulas ∑

l
-1

j
mn
-
k

α
ij

x

mn
+
j

-
h
∑

l
-1

j
mn
-
k

β
ij

x

mn
+
j

= 0,
i
= 1, ···,
l
, where
x

mn
+
j

=
y

mn
+
j

for
j
= -
k
, ···, -1 and

x
n

= ƒ

n

= ƒ(

x
n
, t
n

). These formulas are solved simultaneously for the
x

mn
+
j

with
j
= 0, ···,
l
- 1 in terms of the
x

mn
+
j

with
j
= -
k
, ··· , - 1, which are assumed to be known.

Then
y

mn
+
j

is defined to be
x

mn
+
j

for
j
= 0, ··· ,
m
- 1. For
j
=
m
, ··· ,
l
- 1,
x

mn
+
j

is discarded. The set of
y
's generated in this manner for successive values of
n
provide an approximate solution of the initial value problem:
y
= ƒ(
y, t
),
y
(
t
0
) =
y
0
. It is conjectured that if the method, which is referred to as the composite multistep method, is
A
-stable, then its maximum order is 2
l
. In addition to noting that the conjecture conforms to Dahlquist's bound of 2 for
l
= 1, the conjecture is verified for
k
= 1. A third-order
A
-stable method with
m
=
l
= 2 is given as an example, and numerical results established in applying a fourth-order
A
-stable method with
m
= 1 and
l
= 2 are described.
A
-stable methods with
m
=
l
offer the promise of high order and a minimum of function evaluations—evaluation of ƒ(
y, t
) at solution points. Furthermore, the prospect that such methods might exist with
k
= 1—only one past point—means that step-size control can be easily implemented
Some Results in Computational Topology
Authors: Tourlakis G. , Mylopoulos J.
Published: July 2002

It is the object of this paper to study the topological properties of finite graphs that can be embedded in the
n
-dimensional integral lattice (denoted

N
n

). The basic notion of deletability of a node is first introduced. A node is deletable with respect to a graph if certain computable conditions are satisfied on its neighborhood. An equivalence relation on graphs called reducibility and denoted by “∼” is then defined in terms of deletability, and it is shown that (a) most important topological properties of the graph (homotogy, homology, and cohomology groups) are ∼-invariants; (b) for graphs embedded in
N
3
, different knot types belong to different ∼-equivalence classes; (c) it is decidable whether two graphs are reducible to each other in
N
2
but this problem is undecidable in

N
n

for
n
≥ 4. Finally, it is shown that two different methods of approximating an
n
-dimensional closed manifold with boundary by a graph of the type studied in this paper lead to graphs whose corresponding homology groups are isomorphic.
The Solution of a Toeplitz Set of Linear Equations
Authors: Zohar Shalhav
Published: July 2002

The solution of a set of
m
linear equations with a non-Hermitian Toeplitz associated matrix is considered. Presently available fast algorithms solve this set with 4
m
2
“operations” (an “operation” is defined here as a set of one addition and one multiplication). An improved algorithm requiring only 3
m
2
“operations” is presented.
Efficient Algorithms for Shortest Paths in Sparse Networks
Authors: Johnson Donald B.
Published: July 2002

Algorithms for finding shortest paths are presented which are faster than algorithms previously known on networks which are relatively sparse in arcs. Known results which the results of this paper extend are surveyed briefly and analyzed. A new implementation for priority queues is employed, and a class of “arc set partition” algorithms is introduced. For the single source problem on networks with nonnegative arcs a running time of
O
(min(
n

1+1/
k

+
e
,
n
+
e
) log
n
)) is achieved, where there are
n
nodes and
e
arcs, and
k
is a fixed integer satisfying
k
> 0. This bound is
O
(
e
) on dense networks. For the single source and all pairs problem on unrestricted networks the running time is
O
(min(
n

2+1/
k

+
ne
,
n
2
log
n
+
ne
log
n
).
A code-motion pruning technique for global scheduling
Authors: Dos Santos Luiz C. V. , Heijligers M. J. M. , Van Eijk C. A. J. , Van Eijnhoven J. , Jess J. A. G.
Published: July 2002

In the high-level synthesis of ASICs or in the code generation for ASIPs, the presence of conditionals in the behavioral description represents an obstacle to exploit parallelism. Most existing methods use greedy choices in such a way that the search space is limited by the applied heuristics. For example, they might miss opportunities to optimize across basic block boundaries when treating conditional execution. We propose a constructive method which allows generalized code motions. Scheduling and code motion are encoded in the form of a unified resource-constrained optimization problem. In our approach many alternative solutions are constructed and explored by a search algorithm, while optimal solutions are kept in the search space. Our method can cope with issues like speculative execution and code such duplication. Moreover, it can tackle constraints imposed by the advance choice of a controller, such as pipelined-control delay and limited branch capabilities. The underlying timing models support chaining and multicycling. As tasking code motion into account may lead to a larger search space, a code-motion pruning technique is presented. This pruning is proven to keep optimal solutions in the search space for cost functions in terms of schedule lengths.
Issues in the pragmatics of qualitative modeling: lessons learned from a xerographics project
Authors: Shrager Jeff , Jordan Daniel S. , Moran Thomas P. , Kiczales Gregor , Russell Daniel M.
Published: July 2002

The photocopier is one of the most complex machines because xerography involves many types of physical phenomena. ARIA is a qualitative simulation of xerography that is intended to teach technicians the reasons behind some of the subtle problems that occur in copiers. This effort to model xerography exposed shortcomings in the techniques of qualitative modeling as applied to complex systems and helped to better understand the impact of certain basic modeling decisions.
Mining and visualizing recommendation spaces for elliptic PDEs with continuous attributes
Authors: Ramakrishnan Naren , Ribbens Calvin J.
Published: July 2002

In this paper we extend previous work in mining recommendation spaces based on symbolic problem features to PDE problems with continuous-valued attributes. We identify the research issues in mining such spaces, present a dynamic programming algorithm form the data-mining literature, and describe how
a priori
domain metaknowledge can be used to control the complexity of induction. A visualization aid for continuous-valued recommendation spaces is also outlined. Two case studies are presented to illustrate our approach and tools: (i) a comparison of an iterative and a direct linear system solver on nearly singular problems, and (ii) a comparison of two iterative solvers on problems posed on nonrectangular domains. Both case studies involve continuously varying problem and method parameters which strongly influence the choice of best algorithm in particular cases. By mining the results from thousands of PDE solves, we can gain valuable insight into the relative performance of these methods on similar problems.
Satchel
Authors: Lamming Mik , Eldridge Marge , Flynn Mike , Jones Chris , Pendlebury David
Published: July 2002

Current solutions for providing access to electronic documents while away from the office do not meet the special needs of mobile document workers. We describe ”Satchel,“ a system that is designed specifically to support the distinctive features of mobile document work. Satchel is designed to meet the following five high-level design goals (1) easy access to document services; (2) timely document access; (3) streamlined user interface; (4) ubiquity; and (5)compliance with security policies. Our current prototype uses a Nokia 9000 Communicator as the mobile device; it communicates to the rest of the Satchel system using wireless communications, both infrared and radio. A fundamental Satchel concept is the use of tokens, or small secure references, to represent documents on the mobile device. The mobile client only transmits small tokens over te wireless channels, leaving the wired network to transmit the contents of documents when, and only when, they are required. Another fundmental Satchel concept is the highly speclized and context-sensitive user interface on the mobile device. The user's interactions ae streamlined because of this specialization and though the use of contextual information gained by uing infrared communications. We report the results of a trial of Satchel that was carried out within our own company, and discuss how well Satchel met our design goals. We call Satchel a ”document appliance” because it provides a streamlined soultion to the problem of remote document access—it aims to support only a limited set of activities, but supports them very well.
Studying programmer behavior experimentally
Authors: Brooks Ruven E.
Published: July 2002

The application of behavioral or psychological techniques to the evaluation of programming languages and techniques is an approach which has found increased applicability over the past decade. In order to use this approach successfully, investigators must pay close attention to methodological issues, both in order to insure the generalizability of their findings and to defend the quality of their work to researchers in other fields. Three major areas of methodological concern, the selection of subjects, materials, and measures, are reviewed. The first two of these areas continue to present major difficulties for this type of research.
Data prefetch mechanisms
Authors: Vanderwiel Steven P. , Lilja David J.
Published: July 2002

The expanding gap between microprocessor and DRAM performance has
necessitated the use of increasingly aggressive techniques designed to reduce or hide the latency of main memory access. Although large cache hierarchies have proven to be effective in reducing this latency for the most frequently used data, it is still not uncommon for many programs to spend more than half their run times stalled on memory requests. Data prefetching has been proposed as a technique for hiding the access latency of data referencing patterns that defeat caching strategies. Rather than waiting for a cache miss to initiate a memory fetch, data prefetching anticipates such misses and issues a fetch to the memory system in advance of the actual memory reference. To be effective, prefetching must be implemented in such a way that prefetches are timely, useful, and introduce little overhead. Secondary effects such as cache pollution and increased memory bandwidth requirements must also be taken into consideration. Despite these obstacles, prefetching has the potential to significantly improve overall program execution time by overlapping computation with memory accesses. Prefetching strategies are diverse, and no single strategy has yet been proposed that provides optimal performance. The following survey examines several alternative approaches, and discusses the design tradeoffs involved when implementing a data prefetch strategy.
FOCUS microcomputer number system
Authors: Edgar Albert D. , Lee Samuel C.
Published: July 2002

FOCUS is a number system and supporting computational algorithms especially useful for microcomputer control and other signal processing applications. FOCUS has the wide-ranging character of floating-point numbers with a uniformity of state distributions that give FOCUS better than a twofold accuracy advantage over an equal word length floating-point system. FOCUS computations are typically five times faster than single precision fixed-point or integer arithmetic for a mixture of operations, comparable in speed with hardware arithmetic for many applications. Algorithms for 8-bit and 16-bit implementations of FOCUS are included.
The lemniscate constants
Authors: Todd John
Published: July 2002

The lemniscate constants, and indeed some of the methods used for actually computing them, have played an enormous part in the development of mathematics. An account is given here of some of the methods used—most of the derivations can be made by elementary methods. This material can be used for teaching purposes, and there is much relevant and interesting historical material. The acceleration methods developed for the purpose of evaluating these constants are useful in other problems.
The restriction language for computer grammars of natural language
Authors: Sager Naomi , Grishman Ralph
Published: July 2002

Over the past few years, a number of systems for the computer analysis of natural language sentences have been based on augmented context-free grammars: a context-free grammar which defines a set of parse trees for a sentence, plus a group of restrictions to which a tree must conform in order to be a valid sentence analysis. As the coverage of the grammar is increased, an efficient representation becomes essential for further development. This paper presents a programming language designed specifically for the compact and perspicuous statement of restrictions of a natural language grammar. It is based on ten years' experience parsing text sentences with the comprehensive English grammar of the N.Y.U. Linguistic String Project, and embodies in its syntax and routines the relations which were found to be useful and adequate for computerized natural language analysis. The language is used in the current implementation of the Linguistic String Parser.
Self-stabilizing systems in spite of distributed control
Authors: Dijkstra Edsger W.
Published: July 2002

The synchronization task between loosely coupled cyclic sequential processes (as can be distinguished in, for instance, operating systems) can be viewed as keeping the relation “the system is in a legitimate state” invariant. As a result, each individual process step that could possibly cause violation of that relation has to be preceded by a test deciding whether the process in question is allowed to proceed or has to be delayed. The resulting design is readily—and quite systematically—implemented if the different processes can be granted mutually exclusive access to a common store in which “the current system state” is recorded.
Automatic data structure choice in a language of very high level
Authors: Schwartz J. T.
Published: July 2002

SETL is a set-theoretically oriented language of very high level whose repertoire of semantic objects includes finite sets, ordered n-tuples, and sets of ordered n-tuples usable as mappings. This paper describes the structure of an optimizer for this language. Among other methods of interest, the optimizer uses techniques which allow relations of inclusion and membership to be established, the domains and ranges of (tabulated) mappings to be estimated from above and below, and the single-valuedness of (tabulated) mappings to be proved. Once facts of this kind have been established, automatic choice of data structures becomes possible. The methods employed are based upon, and extend, known techniques of data flow analysis.
An overview of the ISPL computer systems design
Authors: Balzer R. M.
Published: July 2002

This paper explores the advantages of the concurrent design of the language, operating system, and machine (via microcode) to create an interactive programming laboratory. It describes the synergistic effect that the freedom to move and alter features from one of these domains to another has had on the design of this system (which has not been implemented). This freedom simplified both incremental compilation and the system's addressing structure, and centralized the communication mechanisms enabling the construction of hierarchical subsystems. It also suggested an important new concept for operating systems: separation of the scheduling from the maintenance functions in resource allocation. This separation enables incorporation of new scheduling algorithms (decision of what to do) without endangering the system integration (correctly performing the scheduling decisions).
String processing techniques
Authors: Madnick Stuart E.
Published: July 2002

The internal organization of string processing systems is discussed. Six techniques for data structures are presented and evaluated on the basis of: (1) creation of strings; (2) examination of strings; and (3) alteration of strings. Speed of operation, storage requirements, effect on paging, and programmer convenience are also considered. One of the techniques, single-word linked blocks, is used in an example demonstrating an implementation of a SNOBOL string processing language on an IBM System/360.
The use of English as a programming language
Authors: Sammet Jean E.
Published: July 2002

The purpose of this talk is to make a personal plea, backed up by some practical comments, for the use of English or anyone else's natural language as a programming language. This seems to be a suitable subject for the conference, since whatever definition of pragmatics is decided upon, it certainly seems to be tied in with the users of any programming language and what the language means to them.
Mathematical experimentation in time-lag modulation
Authors: Bellman Richard , Buell June , Kalaba Robert
Published: July 2002

Equations of the form
du
/
dt
=
g
(
u
(
t
),
u
(
h
(
t
))) arise in a number of scientific contexts. The authors point out some interesting properties of the solution of
u
′(
t
) = -
u
(
t
- 1 -
k
sin
ωt
) + sin
at
. These properties were obtained by means of numerical solution.
The BKS system for the Philco-2000
Authors: Smith Richard B.
Published: July 2002

The BKS System is a program sequencing system designed for the Philco-2000 computer to meet operational requirements of the Bettis and Knolls Atomic Power Laboratories. The Philco-2000 on which this system is being used has a 32,768-word memory, 16 tape transports on-line, and an electric typewriter on-line. The card-to-tape, card-to-printer, tape-to-card, tape-to-printer, and routine tape-to-tape operations are performed with off-line equipment.
Source-oriented topology aggregation with multiple QoS parameters in hierarchical networks
Authors: Korkmaz Turgay , Krunz Marwan
Published: July 2002

In this paper, we investigate the problem of topology aggregation (TA) for scalable, QoS-based routing in hierarchical networks. TA is the process of summarizing the topological information of a subset of network elements. This summary is flooded throughout the network and used by various nodes to determine appropriate routes for connection requests. A key issue in the design of a TA scheme is the appropriate balance between compaction and the corresponding routing performance. The contributions of this paper are twofold. First, we introduce a source-oriented approach to TA, hich provides better performance than existing approaches. The intuition behind this approach is that the advertised topology-state information is used by
source
nodes to determine tentative routes for connection requests. Accordingly, only information relevant to source nodes needs to be advertised. We integrate the source-oriented approach into three new TA schemes that provide different trade-offs between compaction and accuracy. Second, we extend our source-oriented approach to multi-QoS-based TA. A key issue here is the determination of appropriate values for the multiple QoS parameters associated with a logical link. Two new approaches to computing these values are introduced. Extensive simulations are used to evaluate the performance of out proposed schemes.
Object representation by means of nonminimal division quadtrees and octrees
Authors: Ayala D. , Brunet P. , Juan R. , Navazo I.
Published: July 2002

Quadtree representation of two-dimensional objects is performed with a tree that describes the recursive subdivision of the more complex parts of a picture until the desired resolution is reached. At the end, all the leaves of the tree are square cells that lie completely inside or outside the object. There are two great disadvantages in the use of quadtrees as a representation scheme for objects in geometric modeling system: The amount of memory required for polygonal objects is too great, and it is difficult to recompute the boundary representation of the object after some Boolean operations have been performed. In the present paper a new class of quadtrees, in which nodes may contain zero or one edge, is introduced. By using these quadtrees, storage requirements are reduced and it is possible to obtain the exact backward conversion to boundary representation. Algorithms for the generation of the quadtree, Boolean operations, and recomputation of the boundary representation are presented, and their complexities in time and space are discussed. Three-dimensional algorithms working on octrees are also presented. Their use in the geometric modeling of three-dimensional polyhedral objects is discussed.
Impact of system response time on state anxiety
Authors: Guynes Jan L.
Published: July 2002

Recent research has shown that user satisfaction and productivity are affected by system response time. Our purpose is to provide the results of empirical research on system response time and its effect on state anxiety. Test subjects were classified as Type A or Type B personality in order to determine if personality type had any affect on the relationship between system response time and state anxiety. The results show that both Type A and Type B personalities exhibit a statistically significant increase in state anxiety during poor or variable system response times.
DSS design: a systemic view of decision support
Authors: Ariav Gad , Ginzberg Michael J.
Published: July 2002

A systemic view of DSS can provide a concrete framework for effective design of DSS and can also serve as a basis for accumulating DSS research results.
Finite monoids and the fine structure of
NC
1
Authors: Barrington David A. Mix , Thérien Denis
Published: July 2002

Recently a new connection was discovered between the parallel complexity class
NC
1
and the theory of finite automata in the work of Barrington on bounded width branching programs. There (nonuniform)
NC
1
was characterized as those languages recognized by a certain nonuniform version of a DFA. Here we extend this characterization to show that the internal structures of
NC
1
and the class of automata are closely related.

In particular, using Thérien's classification of finite monoids, we give new characterizations of the classes
AC
0
, depth-
k
AC
0
, and
ACC
, the last being the
AC
0
closure of the mod
q
functions for all constant
q
. We settle some of the open questions in [3], give a new proof that the dot-depth hierarchy of algebraic automata theory is infinite [8], and offer a new framework for understanding the internal structure of
NC
1
.
Computing graphical queries over XML data
Authors: Comai Sara , Damiani Ernesto , Fraternali Piero
Published: July 2002

The rapid evolution of XML from a mere data exchange format to a universal syntax for encoding domain-specific information raises the need for new query languages specifically conceived to address the characteristics of XML. Such languages should be able not only to extract information from XML documents, but also to apply powerful transformation and restructuring operators, based on a well-defined semantics. Moreover, XML queries should be natural to write and understand, as nontechnical persons also are expected to access the large XML information bases supporting their businesses. This article describes XML-GL, a graphical query language for XML data. XML-GL's uniqueness is in the definition of a graph-based syntax to express a wide variety of XML queries, ranging from simple selections to expressive data transformations involving grouping, aggregation, and arithmetic calculations. XML-GL has an operational semantics based on the notion of graph matching, which serves as a guideline both for the implementation of native processors, and for the adoption of XML-GL as a front-end to any of the XML query languages that are presently under discussion as the standard paradigm for querying XML data.
A framework for geometric warps and deformations
Authors: Milliron Tim , Jensen Robert J. , Barzel Ronen , Finkelstein Adam
Published: July 2002

We present a framework for geometric warps and deformations. The framework provides a conceptual and mathematical foundation for analyzing known warps and for developing new warps, and serves as a common base for many warps and deformations. Our framework is composed of two components: a generic modular algorithm for warps and deformations; and a concise, geometrically meaningful formula that describes how warps are evaluated. Together, these two elements comprise a complete framework useful for analyzing, evaluating, designing, and implementing deformation algorithms. While the framework is independent of user-interfaces and geometric model representations and is formally capable of describing
any
warping algorithm, its design is geared toward the most prevalent class of user-controlled deformations: those computed using geometric operations. To demonstrate the expressive power of the framework, we cast several well-known warps in terms of the framework. To illustrate the framework's usefulness for analyzing and modifying existing warps, we present variations of these warps that provide additional functionality or improved behavior. To show the utility of the framework for developing new warps, we design a novel 3-D warping algorithm: a
mesh warp
---useful as a modeling and animation tool---that allows users to deform a detailed surface by manipulating a low-resolution mesh of similar shape. Finally, to demonstrate the mathematical utility of the framework, we use the framework to develop guarantees of several mathematical properties such as commutativity and continuity for large classes of deformations.
An object-oriented requirements specifications method
Authors: Bailin S. C.
Published: July 2002

Analyzing requirements for object-oriented software is examined in an alternative methodology from the more standard structured analysis approach. Through parallel processes of decomposing objects and allocating functions, the methodology is explained in detail.
Efficient placement of audio data on optical disks for real-time applications
Authors: Yu Clement , Sun Wei , Bitton Dina , Yang Qi , Bruno Richard , Tullis John
Published: July 2002

Optical disks are among the most promising secondary storage devices for data-intensive applications and database management systems. A means of optimizing the storage capacity of optical disks is presented here.
The displacement method for implicit blending surfaces in solid models
Authors: Rockwood A. P.
Published: July 2002

To date, methods that blend solids, that is, B-rep or CSG models, with implicit functions require successive composition of the blending functions to handle an arbitrary solid model. The shape of the resulting surfaces depends upon the algebraic distances defined by these functions. To achieve meaningful shapes, previous methods have relied on blending functions that have a pseudo-Euclidean distance measure. These methods are abstracted, resulting in some general observations. Unfortunately, the functions used can exhibit unwanted discontinuities. A new method, the displacement form of blending, embeds the zero surface of the blending functions in a form for which algebraic distance is C
1
continuous in the entire domain of definition.

Characteristics of the displacement form are demonstrated using the superelliptic blending functions. Intuitive and mathematical underpinnings are provided.
A new model for handling input
Authors: Myers Brad A.
Published: July 2002

Although there has been important progress in models and packages for theoutputof graphics to computer screens, there has been little change in the way thatinputfrom the mouse, keyboard, and other input devices is handled. New graphics standards are still using a fifteen-year-old model even though it is widely accepted as inadequate, and most modern window managers simply return a stream of low-level, device-dependent input events. This paper presents a new model that handles input devices for highly interactive, direct manipulation, graphical user interfaces, which could be used in future toolkits, window managers, and graphics standards. This model encapsulates interactive behaviors into a few “Interactor” object types. Application programs can then create instances of these Interactor objects which hide the details of the underlying window manager events. In addition, Interactors allow a clean separation between the input handling, the graphics, and the application programs. This model has been extensively used as part of the Garnet system and has proven to be convenient, efficient, and easy to learn.
NATURE OF MIXED-LAYER CLAYS AND MECHANISMS OF THEIR FORMATION AND ALTERATION
Authors: Środoń Jan
Published: July 2002

▪ Abstract  Mixed-layer clay minerals are intermediate products of reactions involving pure end-member clays. They come from natural environments ranging from surface to low-grade metamorphic and hydrothermal conditions. Most often mixed layering is essentially two component, but more complicated interstratifications have also been documented. Variable tendency to form regular 1:1 interstratifications has been observed and explanations of this phenomenon have been proposed. Mixed-layer clays are either di- or trioctahedral; di/trioctahedral interstratifications are rare. Most mixed-layer clays contain smectite or vermiculte as a swelling component. Exceptions are all trioctahedral: serpentine/chlorite in low-temperature environments, and mica/chlorite and talc/chlorite at high temperatures. Solid state transformation and dissolution/crystallization are the two mechanisms responsible for the formation of different mixed-layer clays. In general, the weathering reactions that produce mixed layering are reversals of the corresponding high-temperature reactions, but the reaction paths are quite different. Weathering reactions alter smectite into kaolinite via mixed-layer kaolinite/smectite. Illite, chlorite, and micas react into mixed-layer clays involving vermiculite layer, then into vermiculite, and finally smectite. Interstratifications of smectite and glauconite, serpentine and chlorite, and smectite and talc are characteristic of early diagenesis and indicative of sedimentary environments. Three reactions involving mixed-layer clays—smectite to illite, smectite to chlorite, and serpentine/chlorite to chlorite—proceed gradually during burial diagenesis and are used for reconstructing maximum burial conditions, illite/smectite being the most useful tool. Rectorite, tosudite, talc/chlorite, and mica/chlorite are mixed-layer minerals indicative of temperatures higher than diagenetic, characteristic of low-temperature metamorphism or hydrothermal alteration.
Plant Competition Underground
Authors: Casper Brenda B. , Jackson Robert B.
Published: July 2002

Belowground competition occurs when plants decrease the growth, survival, or fecundity of neighbors by reducing available soil resources. Competition belowground can be stronger and involve many more neighbors than aboveground competition. Physiological ecologists and population or community ecologists have traditionally studied belowground competition from different perspectives. Physiologically based studies often measure resource uptake without determining the integrated consequences for plant performance, while population or community level studies examine plant performance but fail to identify the resource intermediary or mechanism. Belowground competitive ability is correlated with such attributes as root density, surface area, and plasticity either in root growth or in the properties of enzymes involved in nutrient uptake. Unlike competition for light, in which larger plants have a disproportionate advantage by shading smaller ones, competition for soil resources is apparently more symmetric. Belowground competition often decreases with increases in nutrient levels, but it is premature to generalize about the relative importance of above- and belowground competition across resource gradients. Although shoot and root competition are often assumed to have additive effects on plant growth, some studies provide evidence to the contrary, and potential interactions between the two forms of competition should be considered in future investigations. Other research recommendations include the simultaneous study of root and shoot gaps, since their closures may not occur simultaneously, and improved estimates of the belowground neighborhood. Only by combining the tools and perspectives from physiological ecology and population and community biology can we fully understand how soil characteristics, neighborhood structure, and global climate change influence or are influenced by plant competition belowground.
TECHNOLOGIESSUPPORTIVE OFSUSTAINABLETRANSPORTATION
Authors: Dearing A.
Published: July 2002

▪ Abstract  Meeting the growing demand for personal mobility and transport of goods in a sustainable way presents a wide range of interrelated engineering and public policy challenges. This chapter reviews some of the technical options being developed for mitigating the local and global environmental impact of road vehicles, made possible using developments in the materials and combustion sciences, sensor technologies, catalysis, and information processing. Although the improved technical performance of these options can be quantified, the likelihood of commercial success is harder to predict. This review considers factors that may support the adoption of innovative vehicle technologies, recognizing that the ubiquity of existing solutions and infrastructures will make any change process complex.
Insecticide Resistance in Insect Vectors of Human Disease
Authors: Hemingway Janet , Ranson Hilary
Published: July 2002

▪ Abstract  Insecticide resistance is an increasing problem in many insect vectors of disease. Our knowledge of the basic mechanisms underlying resistance to commonly used insecticides is well established. Molecular techniques have recently allowed us to start and dissect most of these mechanisms at the DNA level. The next major challenge will be to use this molecular understanding of resistance to develop novel strategies with which we can truly manage resistance. State-of-the-art information on resistance in insect vectors of disease is reviewed in this context.
UNSTRUCTURED GRID TECHNIQUES
Authors: Mavriplis D. J.
Published: July 2002

▪ Abstract  An overview of the current state of the art in unstructured mesh techniques for computational fluid dynamics is given. The topics of mesh generation and adaptation, spatial discretization, and solution techniques for steady flows are covered. Remaining difficulties in these areas are highlighted, and directions for future work are outlined.
TUMOR SUPPRESSOR GENE MUTATIONS IN MICE
Authors: Jacks Tyler
Published: July 2002

▪ Abstract  Over the past several years, a number of human tumor suppressor genes have been cloned and characterized. Germline mutations in tumor suppressor genes strongly predispose to cancer, and they are also mutated somatically in sporadic forms of the disease. In order to create animal models for the familial cancer syndromes caused by inherited mutations in these genes as well as to determine their role in embryogenesis, the homologues of several members of this class have been mutated in the mouse. The initial characterization of the heterozygous and homozygous phenotypes caused by these mutations has led to important insights into the mechanisms by which tumor suppressor genes participate in normal development and how their loss contributes to tumorigenesis.
THE ETHYLENE GAS SIGNAL TRANSDUCTION PATHWAY: A Molecular Perspective
Authors: Johnson Phoebe R. , Ecker Joseph R.
Published: July 2002

▪ Abstract  The gaseous hormone ethylene induces diverse effects in plants throughout their life cycle. Ethylene response is regulated at multiple levels, from hormone synthesis and perception to signal transduction and transcriptional regulation. As more genes in the ethylene response pathway are cloned and characterized, they illustrate the precision with which signaling can be controlled. Wounding, pathogenic attack, flooding, fruit ripening, development, senescence, and ethylene treatment itself induce ethylene production. Ethylene binding to receptors with homology to two-component regulators triggers a kinase cascade that is propagated through the CTR1 Raf-like kinase and other components to the nucleus. Activation of the EIN3 family of nuclear proteins leads to induction of the relevant ethyleneresponsive genes via other transcription factors, eliciting a response appropriate to the original stimulus.
NK CELL RECEPTORS
Authors: Lanier Lewis L.
Published: July 2002

▪ Abstract  NK cells are regulated by opposing signals from receptors that activate and inhibit effector function. While positive stimulation may be initiated by an array of co-stimulatory receptors, specificity is provided by inhibitory signals transduced by receptors for MHC class I. Three distinct receptor families, Ly49, CD94/NKG2, and KIR, are involved in NK cell recognition of polymorphic MHC class I molecules. A common pathway of inhibitory signaling is provided by ITIM sequences in the cytoplasmic domains of these otherwise structurally diverse receptors. Upon ligand binding and activation, the inhibitory NK cell receptors become tyrosine phosphorylated and recruit tyrosine phosphatases, SHP-1 and possibly SHP-2, resulting in inhibition of NK cell–mediated cytotoxicity and cytokine expression. Recent studies suggest these inhibitory NK cell receptors are members of a larger superfamily containing ITIM sequences, the inhibitory receptor superfamily (IRS).
Synthetic Cells–Self-Assembling Polymer Membranes and Bioadhesive Colloids
Authors: Hammer Daniel A , Discher Dennis E
Published: July 2002

▪ Abstract  We summarize developments in the construction of synthetic cells made from polymers, with a particular focus on mimicking the structure and behavior of blood cells. Two basic themes emerge—the use of block copolymers to make polmer vesicles and the functionalization of colloidal or polymeric microspheres with cell-like adhesive properties. Both platforms provide a means for building the complex hierarchy that is characteristic of biological cells, while also incorporating novel and perhaps superior properties of material strength, specific targeting, and controlled release.
MOLECULAR APPROACHES TO AMYOTROPHIC LATERAL SCLEROSIS
Authors: Smith, M.D., Ph.D R. Glenn , Appel, M.D Stanley H.
Published: July 2002

▪ Abstract  New discoveries are expanding our knowledge of mechanisms involved in amyotrophic lateral sclerosis (ALS) pathogenesis. Some recent advances in our understanding of motoneuron death in familial ALS (fALS) and sporadic ALS (sALS) are reviewed, with emphasis on molecular similarities that may further unite these phenotypically linked diseases.
EXPLAINING FATIGUE IN CONGESTIVE HEART FAILURE
Authors: Drexler, M.D Helmut , Coats, M.D Andrew J.S.
Published: July 2002

▪ Abstract  Fatigue is a prominent symptom in patients with chronic heart failure, limiting physical activity and impairing quality of life. Although the underlying mechanisms are not clearly identified, alterations associated with peripheral adaptation in heart failure appear to play an important role, including a variably impaired peripheral perfusion during exercise, reduced oxidative capacity of skeletal muscle, impaired muscle strength, and possibly reflex mechanisms associated with alterations in the metabolism of skeletal muscle. Exercise training can, in part, reverse these peripheral alterations, improve exercise capacity, and alleviate fatigue.
Ductal Carcinoma In Situ of the Breast
Authors: Silverstein Melvin J.
Published: July 2002

Ductal carcinoma in situ of the breast is a heterogeneous group of lesions with diverse malignant potential. It is the most rapidly growing subgroup in the breast cancer family; it is projected that more than 39,000 new cases will be diagnosed in the United States during 1999. Most new cases are nonpalpable and are discovered mammographically. Treatment is controversial and ranges from excision only, to excision with radiation therapy, to mastectomy. Genetic changes routinely precede morphologic evidence of malignant transformation. Medicine must learn how to recognize these genetic changes, exploit them, and in the future, prevent them.
Attention Deficit/Hyperactivity Disorder Across the Lifespan
Authors: Wilens Timothy E. , Biederman Joseph , Spencer Thomas J.
Published: July 2002

▪ Abstract  Attention deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder presenting for treatment in youth. ADHD is often chronic with prominent symptoms and impairment spanning into adulthood. ADHD is often associated with co-occurring anxiety, mood, and disruptive disorders, as well as substance abuse. The diagnosis of ADHD by careful review of symptoms and impairment is both reliable and valid. Recent genetic, imaging, neurochemistry, and neuropsychological data support the biological underpinning of the disorder. All aspects of an individual's life must be considered in the diagnosis and treatment of ADHD. Pharmacotherapy, including stimulants, antidepressants, and antihypertensives, plays a fundamental role in the management of ADHD across the lifespan.
MESON SPECTROSCOPY AT LEAR
Authors: Landua Rolf
Published: July 2002

▪ Abstract  New results from LEAR experiments on the search for glueballs and other non-[Formula: see text] states have attracted considerable attention, particularly the discovery of the f0(1500), which is an excellent candidate for the scalar glueball. This article gives an overview about the special features of [Formula: see text] annihilation for meson spectroscopy, and about the use of initial and final-state selection for quantum-number filtering. The general model underlying the partial-wave analysis is discussed. An overview about the Crystal Barrel, OBELIX, and Jetset experiments and their results is followed by a comparison of results from other production mechanisms. Finally, an interpretation of the new results is given.
RELATIVISTIC QCD VIEW OF THE DEUTERON
Authors: Carlson C. E. , Hiller J. R. , Holt R. J.
Published: July 2002

▪ Abstract  The length scales for QCD and for nuclear physics are about the same, both about 1 fermi, and this directly motivates a search for a QCD explanation of nuclear phenomena, beginning with the deuteron. We first review the theoretical tools and results relevant to nuclear QCD, and then discuss data for several reactions. In particular, the remarkable data on deuteron photodisintegration agree with the naive perturbative QCD predictions for their scaling behavior and disagree with predictions from traditional approaches. This may be the first distinctive signature wherein considering the quark substructure in a nucleus is crucial in explaining some phenomenon.
The Shears Mechanism in Nuclei
Authors: Clark R. M. , Macchiavelli A. O.
Published: July 2002

▪ Abstract  This chapter reviews the experimental properties of shears bands. The most puzzling characteristic of these structures is the emergence of rotational-like behavior while the nucleus retains a small quadrupole deformation. Regardless of the details of particular theoretical models, it can be shown that the most important degree of freedom in describing the shears mechanism is the shears angle. It is then possible to develop a semiclassical description of the shears mechanism, in which the nature (multipole order) of the interaction between valence protons and neutrons constituting the shears “blades” may be derived and the dynamics of the system described. We discuss the competition between the shears mechanism and collective rotation and mention the connection to “magnetic rotation.” Directions for future theoretical and experimental efforts are suggested.
Developments in Rare Kaon Decay Physics
Authors: Barker A.R. , Kettell S.H.
Published: July 2002

▪ Abstract  We review the current status of the field of rare kaon decays. The study of rare kaon decays has played a key role in the development of the standard model, and the field continues to have significant impact. The two areas of greatest import are the search for physics beyond the standard model and the determination of fundamental standard-model parameters. Due to the exquisite sensitivity of rare kaon decay experiments, searches for new physics can probe very high mass scales. Studies of the K → π ν[Formula: see text] modes in particular, where the first event has recently been seen, will permit tests of the standard-model picture of quark mixing and CP violation.
Energy Loss in Perturbative QCD
Authors: Baier R. , Schiff D. , Zakharov B. G.
Published: July 2002

▪ Abstract  We review the propagation of energetic partons in hot or cold QCD matter, as known from recent work. We summarize advances in the understanding of both collisional and radiative energy loss. Our emphasis is on radiative energy loss, which has very interesting properties that may help to detect the quark-gluon plasma produced in heavy-ion collisions. We describe two different theoretical approaches, which lead to the same radiated gluon energy spectrum. The case of a longitudinally expanding QCD plasma is investigated. The energy lost by a jet with given opening angle is calculated with the aim of making predictions for the suppression (quenching) of hard jet production. Phenomenological implications for the difference between hot and cold matter are discussed. Numerical estimates of the loss suggest that it may be significantly greater in hot matter than in cold. This makes the magnitude of the radiative energy loss a remarkable signal for quark-gluon plasma formation.
NONADIABATICTRANSITIONS: What We Learned from Old Masters and How Much We Owe Them
Authors: Nikitin E. E.
Published: July 2002

▪ Abstract  This chapter discusses the impact of two-state models of nonadiabatic coupling by Landau, Zener, Stückelberg, Rosen, and Teller on the current theory of nonadiabatic interaction. In particular, the idea of analytical continuation of classical dynamical variables into complex-valued phase space and time is emphasized. The development of the basic models over the past 30 years has provided us with a useful means of investigating the nonadiabatic molecular dynamics; this is illustrated by the references to our earlier and most recent work.