bluuebunny/crossref_metadata_2025 huggingface dataset:
Algorithm 473: Computation of Legendre series coefficients [C6]
Authors: Piessens Robert
Published: July 2002

LEGSER
approximates the first
N
+ 1 coefficients

B
n

of the Legendre series expansion of a function ƒ(
x
) having known Chebyshev series coefficients

A
n

. Several algorithms are available for the computation of coefficients

A
n

of the truncated Chebyshev series expansion on [-1, 1] ƒ(
x
) ≃ ∑′

N

n
=0

A
n
T
n

(
x
), (1) where ∑′ donotes a sum whose first term is halved. The commonly used algorithms are based on the orthogonal property of summation of the Chebyshev polynomials [1]. The application of the analogous property of the Legendre polynomials for the calculation of the coefficients

B
n

of the expansion ƒ(
x
) ≃ ∑

N

n
=0

B
n
P
n

(
x
) (2) is less suitable for practical use since it requires the abscissas and weights of the Gauss-Legendre quadrature formulas [2].
Optimizing binary trees grown with a sorting algorithm
Authors: Martin W. A. , Ness D. N.
Published: July 2002

Items can be retrieved from binary trees grown with a form of the Algorithm Quicksort in an average time proportional to log
n
, where
n
is the number of items in the tree. The binary trees grown by this algorithm sometimes have some branches longer than others; therefore, it is possible to reduce the average retrieval time by restructuring the tree to make the branches as uniform in length as possible. An algorithm to do this is presented. The use of this algorithm is discussed, and it is compared with another which restructures the tree after each new item is added.
Optimizing the polyphase sort
Authors: Shell Donald L.
Published: July 2002

Various dispersion algorithms for the polyphase sorting procedure are examined. The optimum algorithm based on minimizing the total number of unit strings read is displayed. The logic of this algorithm is rather complicated; hence, several other new dispersion algorithms with more straightforward logic are presented. Of the simple dispersion algorithms discussed, the Horizontal is best. It does approximately one-fourth to one and one-half percent less reading and writing than most algorithms in use today. An additional two and one-fourth to three percent improvement can be achieved by utilizing the Modified Optimum Algorithm. This algorithm is relatively straightforward, but it requires a fairly close estimate of the total number of unit strings before the dispersion begins.
An anomaly in space-time characteristics of certain programs running in a paging machine
Authors: Belady L. A. , Nelson R. A. , Shedler G. S.
Published: July 2002

The running time of programs in a paging machine generally increases as the store in which programs are constrained to run decreases. Experiment, however, have revealed cases in which the reverse is true: a decrease in the size of the store is accompanied by a decrease in running time.

An informal discussion of the anomalous behavior is given, and for the case of the FIFO replacement algorithm a formal treatment is presented.
Scientific Applications: An algorithm for identifying the ergodic subchains and transient states of a stochastic matrix
Authors: Fox B. L. , Landi D. M.
Published: July 2002

An algorithm for identifying the ergodic subchains and transient states of a stochastic matrix is presented. Applications in Markov renewal programming and in the construction of variable length codes are reviewed, and an updating procedure for dealing with certain sequences of stochastic matrices is discussed. Computation times are investigated experimentally and compared with those of another recently proposed method.
Comparing the combinational complexities of arithmetic functions
Authors: Alt Helmut
Published: July 2002

Methods are presented for finding reductions between the computations of certain arithmetic functions that preserve asymptotic Boolean complexities (circuit depth or size). They can be used to show, for example, that all nonlinear algebraic functions are as difficult as integer multiplication with respect to circuit size. As a consequence, any lower or upper bound (e.g.,
O
(
n
log
n
log log
n
)) for one of them applies to the whole class. It is also shown that, with respect to depth and size simultaneously, multiplication is reducible to any nonlinear and division to any nonpolynomial algebraic function.
An
O
(n
2
(m +
N
log
n
)log
n
) min-cost flow algorithm
Authors: Galil Zvi , Tardos Éva
Published: July 2002

The minimum-cost flow problem is: Given a network with
n
vertices and
m
edges, find a maximum flow of minimum cost. Many network problems are easily reducible to this problem. A polynomial-time algorithm for the problem has been known for some time, but only recently a strongly polynomial algorithm was discovered. In this paper an
O
(
n
2
(
m
+
n
log
n
)log
n
) algorithm is designed. The previous best algorithm, due to Fujishige and Orlin, had an
O
(
m
2
(
m
+
n
log
n
)log
n
) time bound. Thus, for dense graphs an improvement of two orders of magnitude is obtained.

The algorithm in this paper is based on Fujishige's algorithm (which is based on Tardos's algorithm). Fujishige's algorithm consists of up to
m
iterations, each consisting of
O
(
m
log
n
) steps. Each step solves a single source shortest path problem with nonnegative edge lengths. This algorithm is modified in order to make an improved analysis possible. The new algorithm may still consist of up to
m
iterations, and an iteration may still consist of up to
O
(
m
log
n
) steps, but it can still be shown that the total number of steps is bounded by
O
(
n
2
log
n
. The improvement is due to a new technique that relates the time spent to the progress achieved.
A new class of heuristic algorithms for weighted perfect matching
Authors: Grigoriadis M. D. , Kalantari B.
Published: July 2002

The minimum-weight perfect matching problem for complete graphs ofnvertices with edge weights satisfying the triangle inequality is considered. For each nonnegative integerk≤ log3n, and for any perfect matching algorithm that runs int(n) time and has an error bound of ƒ(n) times the optimal weight, anO(max{n2,t(3-kn)})-time heuristic algorithm with an error bound of (7/3)k(1 + ƒ(3kn)) - 1 is given. By the selection ofkas appropriate functions ofn, heuristics that have better running times and/or error bounds than existing ones are derived.
Computational limitations on learning from examples
Authors: Pitt Leonard , Valiant Leslie G.
Published: July 2002

The computational complexity of learning Boolean concepts from examples is investigated. It is shown for various classes of concept representations that these cannot be learned feasibly in a distribution-free sense unless R = NP. These classes include (a) disjunctions of two monomials, (b) Boolean threshold functions, and (c) Boolean formulas in which each variable occurs at most once. Relationships between learning of heuristics and finding approximate solutions to NP-hard optimization problems are given.
A study of student privacy issues at Stanford University
Authors: The Stanford Student Computer and Network Privacy Project
Published: July 2002

An ambitious study by students for students points out privacy policy weaknesses and concerns at Stanford.
Software for estimating sparse Hessian matrices
Authors: Coleman Thomas F. , Garbow Burton S. , Moré Jorge J.
Published: July 2002

The solution of a nonlinear optimization problem often requires an estimate of the Hessian matrix for a function
f
. In large scale problems, the Hessian matrix is usually sparse, and then estimation by differences of gradients is attractive because the number of differences can be small compared to the dimension of the problem. In this paper we describe a set of subroutines whose purpose is to estimate the Hessian matrix with the least possible number of gradient evaluations.
Probabilistic inductive inference
Authors: Pitt L.
Published: July 2002

Inductive inference machines construct programs for total recursive functions given only example values of the functions.
Probabilistic
inductive inference machines are defined, and for various criteria of successful inference, it is asked whether a probabilistic inductive inference machine can infer larger classes of functions if the inference criterion is relaxed to allow inference with probability at least
p
, (0 <
p
< 1) as opposed to requiring certainty. For the most basic criteria of success (
EX
and
BC
), it is shown that any class of functions that can be inferred from examples with probability exceeding 1/2 can be inferred deterministically, and that for probabilities
p
≤ 1/2 there is a discrete hierarchy of inferability parameterized by
p
. The power of probabilistic inference strategies is characterized by equating the classes of probabilistically inferable functions with those classes that can be inferred by
teams
of inductive inference machines (a parallel model of inference), or by a third model called
frequency
inference.
Fast parallel thinning algorithms: parallel speed and connectivity preservation
Authors: Hall R. W.
Published: July 2002

A recently published parallel thinning approach
[
4
] is evaluated. An improvement is suggested to enable preservation of certain diagonal lines which are not preserved by this algorithm. A unified notion of what is meant by an iteration (or subiteration) and parallel speed is presented, and with regard to its parallel speed this algorithm is argued to be comparable to other two-subiteration algorithms. The parallel speed of this algorithm is compared experimentally to the original algorithm that it improves [
12
] and it is shown that, unlike execution time on a specific machine, parallel speed is not improved. Finally, a more complete connectivity analysis is given illustrating sufficient additional conditions for applying fully in parallel the basic thinning operator used in both algorithms while maintaining all image connectivity properties.
Cyc: toward programs with common sense
Authors: Lenat Douglas B. , Guha R. V. , Pittman Karen , Pratt Dexter , Shepherd Mary
Published: July 2002

Cyc is a bold attempt to assemble a massive knowledge base (on the order of 10
8
axioms) spanning human consensus knowledge. This article examines the need for such an undertaking and reviews the authos' efforts over the past five years to begin its construction. The methodology and history of the project are briefly discussed, followed by a more developed treatment of the current state of the representation language used (epistemological level), techniques for efficient inferencing and default reasoning (heuristic level), and the content and organization of the knowledge base.
Early stopping in Byzantine agreement
Authors: Dolev Danny , Reischuk Ruediger , Strong H. Raymond
Published: July 2002

Two different kinds of Byzantine Agreement for distributed systems with processor faults are defined and compared. The first is required when coordinated actions may be performed by each participant at different times. This kind is called Simultaneous Byzantine Agreement (SBA).

This paper deals with the number of rounds of message exchange required to reach Byzantine Agreement of either kind (BA). If an algorithm allows its participants to reach Byzantine agreement in every execution in which at mosttparticipants are faulty, then the algorithm is said to toleratetfaults. It is well known that any BA algorithm that toleratestfaults (witht<n- 1 wherendenotes the total number of processors) must run at leastt+ 1 rounds in some execution. However, it might be supposed that in executions where the numberfof actual faults is small compared tot, the number of rounds could be correspondingly small. A corollary of our first result states that (whent<n- 1) any algorithm for SBA must runt+ 1 rounds in some execution where there are no faults. For EBA (witht<n- 1), a lower bound of min(t+ 1,f+ 2) rounds is proved. Finally, an algorithm for EBA is presented that achieves the lower bound, provided thattis on the order of the square root of the total number of processors.
Interoperability of multiple autonomous databases
Authors: Litwin Witold , Mark Leo , Roussopoulos Nick
Published: July 2002

Database systems were a solution to the problem of shared access to heterogeneous files created by multiple autonomous applications in a centralized environment. To make data usage easier, the files were replaced by a globally integrated database. To a large extent, the idea was successful, and many databases are now accessible through local and long-haul networks. Unavoidably, users now need shared access to multiple autonomous databases. The question is what the corresponding methodology should be. Should one reapply the database approach to create globally integrated distributed database systems or should a new approach be introduced?

We argue for a new approach to solving such data management system problems, called
multidatabase
or
federated
systems. These systems make databases interoperable, that is, usable without a globally integrated schema. They preserve the autonomy of each database yet support shared access.

Systems of this type will be of major importance in the future. This paper first discusses why this is the case. Then, it presents methodologies for their design. It further shows that major commerical relational database systems are evolving toward multidatabase systems. The paper discusses their capabilities and limitations, presents and discusses a set of prototypes, and, finally, presents some current research issues.
Airway Wall Mechanics
Authors: Kamm Roger D.
Published: July 2002

▪ Abstract  The dimensions, composition, and stiffness of the airway wall are important determinants of airway cross-sectional area during dynamic collapse in a forced expiration or when airway smooth muscle is constricted. Under these circumstances, airway caliber is determined by an interaction between the forces acting to open the airway (parenchymal tension and wall stiffness) and those acting to close it (smooth-muscle force and surface tension at the inner gas-liquid interface). Experimental measurements and theoretical models of the airway tube law (relationship between cross-sectional area and transmural pressure) are presented. Data are presented for the elastic properties of the wall tissue. Simulations of airway constriction in normal and asthmatic airways are discussed. To the extent possible, comparisons are presented between the various models and existing experimental data.
STRUCTURAL PERSPECTIVES OF PHOSPHOLAMBAN, A HELICAL TRANSMEMBRANE PENTAMER
Authors: Arkin Isaiah T. , Adams Paul D. , Brünger Axel T. , Smith Steven O. , Engelman Donald M.
Published: July 2002

▪ Abstract  Phospholamban is a 52-amino-acid protein that assembles into a pentamer in sarcoplasmic reticulum membranes. The protein has a role in the regulation of the resident calcium ATPase through an inhibitory association that can be reversed by phosphorylation. The phosphorylation of phospholamban is initiated by β-adrenergic stimulation, identifying phospholamban as an important component in the stimulation of cardiac activity by β-agonists. It is this role of phospholamban that has motivated studies in recent decades. There is evidence that phospholamban may also function as a Ca2+-selective ion channel. The structural properties of phospholamban have been studied by mutagenesis, modeling, and spectroscopy, resulting in a new view of the organization of this key molecule in membranes.
Conspecific Sperm and Pollen Precedence and Speciation
Authors: Howard Daniel J.
Published: July 2002

▪ Abstract  The evolution of reproductive isolation is perhaps the most significant stage in the process of species formation, and the study of reproductive barriers currently dominates investigations of speciation. The discovery that conspecific sperm and pollen precedence play an important role in the reproductive isolation of some closely related animals and plants is one of the real surprises to emerge from this field in recent years. This review begins with a brief history of the study of reproductive isolation with the aim of understanding why conspecific sperm and pollen precedence were generally overlooked in early work on reproductive barriers. It then examines: case studies, the prevalence of conspecific sperm and pollen precedence, the isolating potential of this class of reproductive barriers, the mechanisms that account for the operation of these barriers, and potential explanations for the rapid divergence of populations in traits related to fertilization. Conspecific sperm and pollen precedence appear to be quite effective in limiting gene exchange; these barriers are widespread although not universal in animals and plants, and they operate through a number of different mechanisms. Much more work remains to be done on a number of fronts to elucidate the processes responsible for the evolution of these reproductive barriers.
NUCLEAR POWER ECONOMIC PERFORMANCE: Challenges and Opportunities
Authors: Kazimi Mujid S. , Todreas Neil E.
Published: July 2002

▪ Abstract  In the last decade, the economics of existing nuclear power plants have improved in the United States and worldwide. Further economic improvements could be realized by better management of planned outages, understanding of unplanned outages, resource sharing among several plants, and more efficient use of nuclear fuel. Dry spent-fuel storage has removed the limitation of on-site storage caused by the limited size of the originally designed storage pools. However, delays and uncertainty about the date by which the national U.S. program will receive the spent fuel have significant financial penalties that could be mitigated if a central interim facility were established to receive spent fuel. Furthermore, a higher incentive for spent-fuel minimization could be obtained if the waste fees were based on spent-fuel volume rather than on electricity sales. Introducing thorium into the fuel cycle has the potential to improve the economics of the fuel cycle while reducing the volume of spent fuel and improving its proliferation resistance.
THE ENGLAND AND WALES NON-FOSSIL FUEL OBLIGATION: History and Lessons
Authors: Mitchell Catherine
Published: July 2002

▪ Abstract  The first phase of promoting renewable energy in Europe is coming to an end. The timetable of the European Commission's Single Electricity Market (SEM) Directive has been the key recent driver of change within European energy and electricity markets. As mainland European countries have been forced to restructure their electricity industries and reappraise their renewable energy policies, they have been impressed by the results of the England and Wales Renewable Non-Fossil Fuel Obligation (NFFO). The NFFO is a mechanism for promoting renewable energy that has a competitive basis. However, the United Kingdom is in the process of creating a new policy. As new renewable energy policies have been discussed or put in place in mainland European countries, so these have influenced those of the United Kingdom. Renewable energy policies throughout Europe are converging. This paper analyzes the history behind these changes and underlines the lessons to be learned.
TESTS OFREPRODUCTIVE-SKEWMODELS INSOCIALINSECTS
Authors: Reeve H. Kern , Keller Laurent
Published: July 2002

▪ Abstract  Reproductive-skew theory can be broadly divided into transactional models, in which reproduction is shared among group members in return for some fitness benefit, and tug-of-war models, in which reproductive sharing arises solely from an inability of each group member to fully control the others. For small-colony social insects in which complete reproductive control by a single individual is plausible, transactional-concession models account, better than any other existing model, for observed relationships between each of the dependent variables of skew, changes in reproductive partitioning over time, group size, and within-group aggression, and each of the predictor variables of genetic relatedness, ecological constraints on solitary breeding, and benefits of group living. An extension of transactional-concession models via the “workers-as-a-collective-dominant” model potentially offers new insights into some of the most striking reproductive patterns in large-colony eusocial Hymenopteran species, from the loss of worker capacity to produce female offspring to patterns of skew and aggression in polygynous societies.
MOLECULAR GENETIC BASIS OF ADAPTIVE SELECTION: Examples From Color Vision in Vertebrates
Authors: Yokoyama Shozo
Published: July 2002

▪ Abstract  A central unanswered question in phototransduction is how photosensitive molecules, visual pigments, regulate their absorption spectra. In nature, there exist various types of visual pigments that are adapted to diverse photic environments. To elucidate the molecular mechanisms involved in the adaptive selection of these pigments, we have to identify amino acid changes of pigments that are potentially important in changing the wavelength of maximal absorption (λmax) and then determine the effects of these mutations on the shift in λmax. The desired mutants can be constructed using site-directed mutagenesis, expressed in tissue culture cells, and the functional effect of virtually any such mutant can be rigorously determined. The availability of these cell/molecular methods makes vision an ideal model system in studying adaptive mechanisms at the molecular level. The identification of potentially important amino acid changes using evolutionary biological means is an indispensable step in elucidating the molecular mechanisms that underlie the spectral tuning of visual pigments.
GENE AMPLIFICATION AND GENOMIC PLASTICITY IN PROKARYOTES
Authors: Romero David , Palacios Rafael
Published: July 2002

▪ Abstract  Gene amplification is a common feature of the genome of prokaryotic organisms. In this review, we analyze different instances of gene amplification in a variety of prokaryotes, including their mechanisms of generation and biological role. Growing evidence supports the concept that gene amplification be considered not as a mutation but rather as a dynamic genomic state related to the adaptation of bacterial populations to changing environmental conditions or biological interactions. In this context, the potentially amplifiable DNA regions impose a defined dynamic structure on the genome. If such structure has indeed been selected during evolution, it is a particularly challenging hypothesis.
THE ROLE OF THE FHIT/FRA3B LOCUS IN CANCER
Authors: Huebner Kay , Garrison Preston N. , Barnes Larry D. , Croce Carlo M.
Published: July 2002

▪ Abstract  Common fragile sites form gaps at characteristic chromosome bands in metaphases from normal cells after aphidicolin induction. The distribution of common fragile sites parallels the positions of neoplasia-associated chromosomal rearrangements, prompting the proposal that fragility disposes to chromosomal rearrangements. Implicit in this hypothesis is that genes at fragile sites are altered by chromosome rearrangement and thus contribute to neoplastic growth. Chromosome band 3p14.2, encompassing the most inducible common fragile region, FRA3B, has been cloned and the FHIT gene, straddling FRA3B, characterized. The gene is inactivated by deletions in cancer-derived cell lines and primary tumors and Fhit protein is absent or reduced in lung, stomach, kidney, and cervical carcinomas, consistent with function as a tumor suppressor. FRA3B thus fulfills the prophecy that fragile site alterations contribute to the neoplastic process through inactivation of a tumor suppressor gene.
Bioinformatics Tools for Whole Genomes
Authors: Searls David B.
Published: July 2002

The advent of whole-genome data resources—not only sequence but also other genome-scale data collections such as gene expression, protein interaction, and genetic variation—is having two marked, complementary effects on the relatively new discipline of bioinformatics. First, the veritable flood of data is creating a need and demand for new tools for dealing adequately with the deluge, and, second, the unprecedented extent, diversity, and impending completeness of the data sets are creating opportunities for new approaches to discovery based on computational methods.
Future Directions in Carbon Science
Authors: Dresselhaus M. S.
Published: July 2002

The materials science of carbon-based materials has enjoyed a tremendous growth in the past half century. Selected highlights are reviewed with emphasis given to future opportunities in this research field.
The Genetics of the Amyloidoses
Authors: Buxbaum Joel N. , Tagoe Clement E.
Published: July 2002

▪ Abstract  The amyloidoses are diseases in which abnormalities in the secondary structure of precursor proteins result in decreased solubility under physiologic conditions, with subsequent organ compromise. A total of 18 proteins have been definitively identified as amyloid precursors associated with human disease. Mutations in the genes that encode some of these proteins produce autosomal dominant disease in mid to late adult life. Until recently, the late onset has obscured the familial nature of some of the disorders. This is especially true in the apparently sporadic diseaseproducing deposits found even later in life. In many instances, these deposits are derived from precursors encoded by wild-type genes (perhaps influenced by alleles that are polymorphic in the normal population); in other cases, they represent autosomal dominant disease with age-dependent penetrance. The genetic aspects of amyloid diseases produced by the deposition of four different proteins have been investigated in detail and provide insights into the particular diseases and amyloidogenesis in general.
Irritable Bowel Syndrome
Authors: Ringel Yehuda , Sperber Ami D. , Drossman Douglas A.
Published: July 2002

▪ Abstract  The irritable bowel syndrome (IBS) is a functional gastrointestinal disorder whose hallmark is abdominal pain or discomfort associated with a change in the consistency or frequency of stools. In the western world, 8% to 23% of adults have IBS and its socioeconomic cost is substantial. Research-generated insights have led to the understanding of IBS as a disorder of brain-gut regulation. The experience of symptoms derives from dysregulation of the bidirectional communication system between the gastrointestinal tract and the brain, mediated by neuroendocrine and immunological factors and modulated by psychosocial factors. The biopsychosocial model integrates the various physical and psychosocial factors that contribute to the patient's illness. This model and the recently revised symptom-based criteria (i.e. the “Rome II criteria”) form the basis for establishing a comprehensive and effective approach for the diagnosis and management of the disorder.
Directions of Drug Discovery in Osteoporosis
Authors: Mundy Gregory R.
Published: July 2002

▪ Abstract  Osteoporosis is a condition of increasing importance and prevalence in all parts of the world and particularly in Asia. Recent advances have led to the introduction of effective drugs that decrease bone resorption and stabilize bone mass. However, these drugs have been identified by serendipity rather than rational drug design and are not ideal because of limited bioavailability, mode of administration, or other unwanted effects. There is still a place for even more suitable and effective resorption inhibitors than those currently available. The more compelling need in this field is an acceptable drug that is anabolic for bone, that safely and acceptably increases bone mass and improves the disturbances in bone microarchitecture that characterize established and advanced osteoporosis. Possible approaches to identifying more effective resorption inhibitors and new anabolic agents are discussed.
Bacterial Gliding Motility: Multiple Mechanisms for Cell Movement over Surfaces
Authors: McBride Mark J.
Published: July 2002

▪ Abstract  The mechanisms responsible for bacterial gliding motility have been a mystery for almost 200 years. Gliding bacteria move actively over surfaces by a process that does not involve flagella. Gliding bacteria are phylogenetically diverse and are abundant in many environments. Recent results indicate that more than one mechanism is needed to explain all forms of bacterial gliding motility. Myxococcus xanthus “social gliding motility” and Synechocystis gliding are similar to bacterial “twitching motility” and rely on type IV pilus extension and retraction for cell movement. In contrast, gliding of filamentous cyanobacteria, mycoplasmas, members of the Cytophaga-Flavobacterium group, and “adventurous gliding” of M. xanthus do not appear to involve pili. The mechanisms of movement employed by these bacteria are still a matter of speculation. Genetic, biochemical, ultrastructural, and behavioral studies are providing insight into the machineries employed by these diverse bacteria that enable them to glide over surfaces.
Odor Encoding as an Active, Dynamical Process: Experiments, Computation, and Theory
Authors: Laurent Gilles , Stopfer Mark , Friedrich Rainer W , Rabinovich Misha I , Volkovskii Alexander , Abarbanel Henry DI
Published: July 2002

▪ Abstract  We examine early olfactory processing in the vertebrate and insect olfactory systems, using a computational perspective. What transformations occur between the first and second olfactory processing stages? What are the causes and consequences of these transformations? To answer these questions, we focus on the functions of olfactory circuit structure and on the role of time in odor-evoked integrative processes. We argue that early olfactory relays are active and dynamical networks, whose actions change the format of odor-related information in very specific ways, so as to refine stimulus identification. Finally, we introduce a new theoretical framework (“winnerless competition”) for the interpretation of these data.
Strangeness Production in Heavy-Ion Collisions
Authors: Margetis Spyridon , Safarík Karel , Villalobos Baillie Orlando
Published: July 2002

▪ Abstract  Strangeness production is a very useful diagnostic tool in finding the quark-gluon plasma. We review its uses in understanding relativistic heavy-ion collisions. A brief introduction to the main theoretical tools used in interpreting strangeness production is given, and the experimental methods used to extract the signals are discussed in detail. The experimental results from the Brookhaven AGS and CERN SPS programs are presented. We discuss the interpretation of these results, emphasizing their role in the discovery of deconfined quark matter at CERN. Future experiments at RHIC and at the CERN LHC are described.
LIPOLYSIS:Contribution from Regional Fat
Authors: Jensen Michael D.
Published: July 2002

▪ Abstract  In vitro studies of adipocytes taken from different body fat regions suggest substantial differences in lipolysis between intra-abdominal, lower-body subcutaneous, and abdominal subcutaneous regions. Gender and obesity appear to influence these regional differences. In situ measurements of glycerol release from adipose tissue provided further evidence that regional heterogeneity of lipolysis occurs in humans. In vivo studies of regional free fatty acid (FFA) release have confirmed that adipose tissue lipolysis varies between upper- and lower-body fat. Release of FFA from lower-body adipose tissue is less than that from upper-body adipose tissue in both obese and non-obese men and women. In non-obese men and women, meal ingestion suppresses FFA release from all adipose tissue regions, and adrenergic stimulation activated FFA release from different sites in a gender-specific fashion. Significant regional and gender differences in adipose tissue lipolysis occur in humans, and this could contribute to differences in the health effects of adipose tissue and could theoretically influence body fat distribution.
The Biochemistry and Physiology of S-Nitrosothiols
Authors: Hogg Neil
Published: July 2002

S-nitrosothiols are biological metabolites of nitric oxide. It has often been suggested that they represent a more stable metabolite of nitric oxide that can either be stored, or transported, although the evidence for this is sparse. There are many unanswered questions concerning how S-nitrosothiols are formed, how they are metabolized and how they elicit biological responses. These questions are highlighted by the fact that the known chemistry of nitric oxide, thiols, and S-nitrosothiols cannot serve to explain their proposed biological activities. This review attempts to highlight the gulf between our chemical understanding of S-nitrosothiols and the proposed biological activities of these compounds with respect to guanylyl cyclase–independent nitric oxide bioactivity and also the control of vascular tone.
COINCIDENCE SPECTROSCOPY
Authors: Continetti Robert E
Published: July 2002

▪ Abstract  The application of coincidence techniques to the study of the reaction dynamics of isolated molecules is reviewed. Coincidence spectroscopy is a powerful approach for carrying out a number of measurements. At its most basic level, coincidence techniques can identify the source of a specific signal, as in the well-known photoelectron-photoion coincidence approach used for several years. By carrying out coincidence experiments in an increasingly differential manner, correlated energy and angular distributions of reaction products may be recorded. Completely energy- and angle-resolved measurements of photoelectrons and ionic or neutral products can reveal molecular-frame photoelectron and photofragment angular distributions and aid in the characterization of dissociative states of molecules and ions. Recent work in this area is reviewed, including examples from studies of dissociative photodetachment, dissociative photoionization, time-resolved studies of dissociative photoionization, and three-body dissociation processes.
DR. GOTTHOLD STEINER (1886–1961): VERSATILE NEMATOLOGIST
Authors: Esser Robert P.
Published: July 2002

[Figure: see text]

▪ Abstract  Swiss-born Dr. Gotthold Steiner was a pioneer in formulating the discipline of nematology. He worked with the American nematologist NA Cobb and together they were responsible for acceptance of the concept of nematode phytoparasites. Steiner had special expertise in anatomy, morphology, phytonematology, marine nematodes, nutrition, mermithids, and selected invertebrate taxa. He authored 191 scientific papers, established the ubiquitous phytoparasitic genus Helicotylenchus, described the pinewood nematode, and did significant work with three important economic pests, Ditylenchus dipsaci, Heterodera rostochiensis, and H. schachtii. He was responsible for introducing training programs in nematology in USDA laboratories.
REFLECTIONS ON SPACE, TIME, AND DIVERSITY
Authors: Zadoks JC
Published: July 2002

▪ Abstract  Farmers motivated and inspired me to pursue a career in plant disease epidemiology. A taste for field observation and a need for reflexion led to a theory of disease foci, which grow in space and time. Quantitative effects are modulated by qualitative factors such as race differentiation of the pathogen and partial resistance of the host plant. Moving to larger scales of operation, within- and between-crop diversity become important. Diversity may be amenable to management. Whereas reductionistic experimentation will remain necessary to explain details, this paper makes a plea to use modern techniques for tackling complexity in crop protection.
Genetic Diversity and Evolution of Closteroviruses
Authors: Karasev Alexander V.
Published: July 2002

The family Closteroviridae comprises more than 30 plant viruses with flexuous, filamentous virions and includes representatives with either mono- or bipartite positive-strand ssRNA genomes. Closteroviruses are transmitted semipersistently by insects from three families of Homoptera, in infected plants are associated with phloem tissue, and demonstrate an astonishing genetic diversity that suggests extensive, on-going evolution. Phylogenetic analyses of their replicative genes as well as the conserved HSP70 demonstrate that closteroviruses co-evolved with their insect vectors, resulting in three major lineages, i.e. aphid-, mealybug-, and whitefly-transmitted viruses. Closteroviruses apparently represent an ancient and diverse virus family that may pose threats to agriculture and needs serious attention.
SOCIAL SCIENCE AND SCIENTIFIC CHANGE: A Note on Thomas S. Kuhn's Contribution
Authors: Polsby Nelson W.
Published: July 2002

▪ Abstract  A new reading is proposed for The Structure of Scientific Revolutions by the late Thomas S. Kuhn, in which the sort of resistance to change he describes as integral to paradigm shifts is found to be less common in the contemporary hard sciences but useful and applicable in understanding political and social science.
PERSONALITY: Individual Differences and Clinical Assessment
Authors: Butcher James N. , Rouse Steven V.
Published: July 2002

▪ Abstract  Research in clinical personality assessment continues to be produced at a high rate. The MMPI/MMPI-2 remains the most popular instrument for both clinical application and psychopathology research. Two other clinical personality instruments, the Rorschach and TAT, continue to find a place in research and clinical assessment. Some new instruments have surfaced recently to deal with areas, such as personality disorders, that have been considered inadequately addressed. There is a growing recognition that the Five-Factor Model is too superficial for clinical assessment that requires more refined and broadened patient information. Clinical personality assessment has successfully survived a number of past challenges. The newest challenge stems from the health-care revolution, in which managed-care providers are reluctant to pay for assessment because of shrinking funds. Psychologists need to develop models for incorporating assessment information into the treatment process. The future is likely to see more extensive research and theoretical development in this endeavor.
HEALTH STATUS ASSESSMENT METHODS FOR ADULTS: Past Accomplishments and Future Challenges
Authors: McHorney Colleen A.
Published: July 2002

▪ Abstract  Over the past 30 years, health status assessment methods for adults have proliferated. Numerous generic, disease-specific, and preference-based measures now exist that tap diverse aspects of functioning, well-being, symptom states, and subjective perceptions of health. The evolution of the state of the art in adult health status assessment is reviewed. Applications of these tools in health services research, health policy, and clinical practice are discussed. Recommendations are offered for selecting among the armamentaria of tools. Conceptual and methodological challenges that confront instrument users and developers alike are identified and discussed.
Morbidity and Mortality from Medical Errors: An Increasingly Serious Public Health Problem
Authors: Phillips David P. , Bredder Charlene C.
Published: July 2002

▪ Abstract  From 1983 to 1998, U.S. fatalities from acknowledged prescription errors increased by 243%, from 2,876 to 9,856. This percentage increase was greater than for almost any other cause of death, and far outpaced the increase in the number of prescriptions. Many nonfatal prescription errors also occur, but estimates of the frequency of these errors vary widely, because various definitions, geographic settings, and institutions have been used. Efforts to reduce fatal and nonfatal prescription errors have encountered perceptual, legal, medical, and cultural barriers. It may be possible to reduce prescription errors by instituting a central agency responsible for collecting, analyzing, and reporting harmful or potentially harmful drug events, and for issuing recommendations and directives.
Grigory Gidoni: Another Renascent Name
Authors: Galeyev Bulat M.
Published: July 2002

The author discusses the life and work of Grigory Gidoni, artist-inventor of the early days of the Soviet Union. Nearly forgotten, Gidoni's works and ideas shed light on the spirit and the artistic and ideological atmosphere of the U.S.S.R. in the decades following the Revolution.
Design Predicts the Future When It Anticipates Experience
Authors: Morello Augusto
Published: July 2002

Design is an activity that, in a complex, computerized society such as the one that we are entering now, calls for appropriate technical skills, creativity, and an attentive eye for aesthetic values, but also a marked ability to ponder the relationship between humanism and the world. This is the new human frontier: designing complexity.
Computer-Based Training of Stimulus Detection Improves Color and Simple Pattern Recognition in the Defective Field of Hemianopic Subjects
Authors: Kasten Erich , Poggel Dorothe A. , Sabel Bernhard A.
Published: July 2002

In a previously conducted randomized placebo-controlled trial, we were able to demonstrate significant visual field enlargement induced by restitution therapy in patients with cerebral lesions [Kasten, E., Wuest, S., Behrens-Bamann, W., & Sabel, B. A. (1998c). Computer-based training for the treatment of partial blindness. Nature Medicine, 4, 1083-1087.]. Visual field training was performed on a computer monitor for 1 hr per day over a period of 6 months. Since the procedure included only stimulation with white light, in the present study we investigated if this simple detection training had a transfer effect on color or form recognition in the trained area (i.e., in the absence of modality specific training). Answering this question would be crucial for planning optimal restitution therapy: In case there is no transfer of training effects to other visual modalities, a specific treatment of each visual function must be performed in order to achieve maximum benefit. Therefore, we analyzed the data from 32 patients with visual field defects who had participated in the original trial and whose form and color recognition had been investigated. The experimental group (n = 19, restitution training) experienced not only an increase of 12.8% correctly detected stimuli (PeriMa program, p < .05), but also an improvement of 5.6% in pattern recognition (PeriForm) and of 6.1% in color perception (PeriColor), respectively. In contrast, the placebo group (n = 13, fixation training) showed no significant changes from baseline to final outcome in any of the visual modalities (PeriMa: 0.3%; PeriForm: -0.3%; PeriColor: 0.4%). Conventional perimetry yielded an increase of 7.8% detected stimuli in the experimental group, but only of 1.2% in the placebo group (p < .05). For form recognition and color perception, the differences between the results of the experimental and the placebo groups narrowly missed significance. However, correlations of diagnostic results showed that mainly those patients who had achieved visual field enlargement also improved in color and form perception: r = .67 (p < .05) between PeriMa and PeriForm and r = .32 between PeriMa and PeriColor. We conclude that visual restitution training using a simple white light stimulus has at least some influence on improving other visual functions such as color and pattern recognition. This result supports the “bottleneck theory” of visual restitution, i.e., training effects can be explained as a process of perceptual learning and increased processing of information by residual structures surviving lesions of the primary visual pathways.
Functional Changes in Brain Activity During Priming in Alzheimer's Disease
Authors: Backman Lars , Almkvist Ove , Nyberg Lars , Andersson Jesper
Published: July 2002

Patients with Alzheimer's disease (AD) are often impaired on certain forms of implicit memory, such as word-stem completion priming (WSCP). Lesion data suggest that deficient WSCP may be associated with abnormal functioning in the posterior neocortex. Using positron emission tomography (PET), we here provide direct support for this view. Compared with normal old adults, AD patients showed reduced priming on a word-stem completion task. The normal old showed decreased activity in right occipital cortex (area 19), whereas the AD patients showed increased activity in this region during priming. To the extent that decreased activity during priming reflects an experience-dependent reduction of the neuronal population involved, these results indicate that shaping of the relevant neurons is slower in AD, possibly as a result of inadequate initial-stimulus processing.
Color Vision and the Four-Color-Map Problem
Authors: Purves Dale , Lotto Beau , Polger Thomas
Published: July 2002

Four different colors are needed to make maps that avoid adjacent countries of the same color. Because the retinal image is two dimensional, like a map, four dimensions of chromatic experience would also be needed to optimally distinguish regions returning spectrally different light to the eye. We therefore suggest that the organization of human color vision according to four-color classes (reds, greens, blues, and yellows) has arisen as a solution to this logical requirement in topology.
Object Activation in Semantic Memory from Visual Multimodal Feature Input
Authors: Kraut Michael A. , Kremen Sarah , Moo Lauren R. , Segal Jessica B. , Calhoun Vincent , Hart John
Published: July 2002

The human brain's representation of objects has been proposed to exist as a network of coactivated neural regions present in multiple cognitive systems. However, it is not known if there is a region specific to the process of activating an integrated object representation in semantic memory from multimodal feature stimuli (e.g., picture–word). A previous study using word–word feature pairs as stimulus input showed that the left thalamus is integrally involved in object activation (Kraut, Kremen, Segal, et al., this issue). In the present study, participants were presented picture–word pairs that are features of objects, with the task being to decide if together they “activated” an object not explicitly presented (e.g., picture of a candle and the word “icing” activate the internal representation of a “cake”). For picture–word pairs that combine to elicit an object, signal change was detected in the ventral temporo-occipital regions, pre-SMA, left primary somatomotor cortex, both caudate nuclei, and the dorsal thalami bilaterally. These findings suggest that the left thalamus is engaged for either picture or word stimuli, but the right thalamus appears to be involved when picture stimuli are also presented with words in semantic object activation tasks. The somatomotor signal changes are likely secondary to activation of the semantic object representations from multimodal visual stimuli.
An MEG Study of Picture Naming
Authors: Levelt Willem J. M. , Praamstra Peter , Meyer Antje S. , Helenius Päivi , Salmelin Riitta
Published: July 2002

The purpose of this study was to relate a psycholinguistic processing model of picture naming to the dynamics of cortical activation during picture naming. The activation was recorded from eight Dutch subjects with a whole-head neuromagnetometer. The processing model, based on extensive naming latency studies, is a stage model. In preparing a picture's name, the speaker performs a chain of specific operations. They are, in this order, computing the visual percept, activating an appropriate lexical concept, selecting the target word from the mental lexicon, phonological encoding, phonetic encoding, and initiation of articulation. The time windows for each of these operations are reasonably well known and could be related to the peak activity of dipole sources in the individual magnetic response patterns. The analyses showed a clear progression over these time windows from early occipital activation, via parietal and temporal to frontal activation. The major specific findings were that (1) a region in the left posterior temporal lobe, agreeing with the location of Wernicke's area, showed prominent activation starting about 200 msec after picture onset and peaking at about 350 msec, (i.e., within the stage of phonological encoding), and (2) a consistent activation was found in the right parietal cortex, peaking at about 230 msec after picture onset, thus preceding and partly overlapping with the left temporal response. An interpretation in terms of the management of visual attention is proposed.