bluuebunny/crossref_metadata_2025 huggingface dataset:
RECEPTORS FOR HLA CLASS-I MOLECULES IN HUMAN NATURAL KILLER CELLS
Authors: Moretta Alessandro , Bottino Cristina , Vitale Massimo , Pende Daniela , Biassoni Roberto , Mingari Maria Cristina , Moretta Lorenzo
Published: July 2002

▪ Abstract  Natural killer cells are likely to play an important role in the host defenses because they kill virally infected or tumor cells but spare normal self-cells. The molecular mechanism that explains why NK cells do not kill indiscriminately has recently been elucidated. It is due to several specialized receptors that recognize major histocompatibility complex (MHC) class I molecules expressed on normal cells. The lack of expression of one or more class I alleles leads to NK-mediated target cell lysis. During NK cell development, the class I–specific receptors have adapted to self–class I molecules on which they recognize epitopes shared by groups of class I alleles. As such, they may fail to recognize either self-molecules that bound unusual peptides or allogeneic class I molecules unrelated to self-alleles. Different types of receptors specific for groups of HLA-C or HLA-B alleles have been identified. While in most instances, they function as inhibiting receptors, an activating form of the HLA-C-specific receptors has been identified in some donors. Molecular cloning of HLA-C- and HLA-B-specific receptors has revealed new members of the immunoglobulin superfamily with two or three Ig-like domains, respectively, in their extracellular portion. While the inhibiting form is characterized by a long cytoplasmic tail associated with a nonpolar transmembrane portion, the activating one has a short tail associated with a Lys-containing transmembrane portion. Thus, these human NK receptors are different from the murine Ly49 that is a type II transmembrane protein characterized by a C type lectin domain. A subset of cytolytic T lymphocytes expresses NK-type class I–specific receptors. These receptors exert an inhibiting activity on T cell receptor–mediated functions and offer a valuable model to analyze the regulatory mechanisms involved in receptor-mediated cell activation and inactivation.
Synthesis and Characterization of Monodisperse Nanocrystals and Close-Packed Nanocrystal Assemblies
Authors: Murray C. B. , Kagan C. R. , Bawendi M. G.
Published: July 2002

▪ Abstract  Solution phase syntheses and size-selective separation methods to prepare semiconductor and metal nanocrystals, tunable in size from ∼1 to 20 nm and monodisperse to ≤5%, are presented. Preparation of monodisperse samples enables systematic characterization of the structural, electronic, and optical properties of materials as they evolve from molecular to bulk in the nanometer size range. Sample uniformity makes it possible to manipulate nanocrystals into close-packed, glassy, and ordered nanocrystal assemblies (superlattices, colloidal crystals, supercrystals). Rigorous structural characterization is critical to understanding the electronic and optical properties of both nanocrystals and their assemblies. At inter-particle separations 5–100 Å, dipole-dipole interactions lead to energy transfer between neighboring nanocrystals, and electronic tunneling between proximal nanocrystals gives rise to dark and photoconductivity. At separations <5 Å, exchange interactions cause otherwise insulating assemblies to become semiconducting, metallic, or superconducting depending on nanocrystal composition. Tailoring the size and composition of the nanocrystals and the length and electronic structure of the matrix may tune the properties of nanocrystal solid-state materials.
PROGNOSIS IN CONGESTIVE HEART FAILURE
Authors: Rector, Ph.D Thomas S. , Cohn, M.D Jay N.
Published: July 2002

▪ Abstract  Prognostic variables such as the ejection fraction and peak oxygen consumption can be used to place patients with heart failure in risk strata. Some vasodilators have been shown to improve survival at all stages of heart failure with the probability of benefit increasing as the prognosis worsens. Quantitative estimates of survival among groups defined by prognostic variables and treatments should be used to make more informed benefit-to-risk assessments.
TISSUE FACTOR PATHWAY INHIBITOR AND THE REVISED THEORY OF COAGULATION
Authors: Broze George J.
Published: July 2002

▪ Abstract  Tissue factor pathway inhibitor (TFPI) is a multivalent, Kunitz-type plasma proteinase inhibitor that regulates tissue factor-induced coagulation. TFPI directly inhibits activated factor X and, in a factor Xa-dependent fashion, produces feedback inhibition of the factor VIIa/tissue factor catalytic complex. The properties of this rediscovered inhibitor appear, at least in part, to explain the clinical requirement for both the extrinsic and intrinsic pathways of the cascade and waterfall theories of blood clotting and have led to a reformulation of the coagulation mechanism. In the revised hypothesis, factor VIIa/tissue factor is responsible for the initiation of coagulation, but owing to TFPI-mediated inhibition, sustained hemostasis requires the persistent and amplified procoagulant action of intrinsic factors VIII, IX, and XI.
THE GENETICIST'S APPROACH TO COMPLEX DISEASE
Authors: Ghosh, M.D., Ph.D Soumitra , Collins, M.D., Ph.D Francis S.
Published: July 2002

▪ Abstract  Many studies are in progress worldwide to elucidate the genetics of complex diseases. Nevertheless, few articles are available that provide the scientific rationale and give guidelines for such ambitious endeavours. We describe the methodology and background necessary to study the genetics of complex disease and discuss how to analyze the data. We also provide a table of some ongoing studies. In particular, we wish to emphasize the analysis of intermediate, heritable, quantitative traits as a means of dissecting the genetic basis of a complex trait.
CURRENT STATUS OF THE SURGICAL TREATMENT OF PATIENTS WITH CAROTID ARTERY DISEASE: The Surgical Management of Carotid Atherosclerosis
Authors: Wittgen, MD C. M. , Brewster, MD D. C.
Published: July 2002

▪ Abstract  Patients with carotid atherosclerotic disease present with a history of a neurologic event or with the presence of a bruit on physical examination. Recently, large randomized prospective studies have examined this group of patients to determine the optimal course of medical and surgical management. The data from these studies, together with the natural history of carotid disease and factors associated with stroke risk, are reviewed.
The Open-Artery Hypothesis
Authors: Solomon A. , Gersh B.
Published: July 2002

Early reperfusion of an infarct-related coronary artery results in myocardial salvage, with subsequent improvement in left ventricular function and survival. However, late reperfusion, which occurs at a time when myocardial salvage is no longer possible, still exerts a favorable impact on left ventricular function and survival. This concept is known as the open-artery hypothesis. Possible mechanisms for this benefit include improved infarct healing, limitation of ventricular remodeling, decreased ventricular arrhythmias, and reperfusion of hibernating myocardium. Although an open infarct-related coronary artery is crucial, it has not been proven that opening an occluded coronary artery using angioplasty is beneficial. A large randomized clinical trial is clearly needed.
Applications of NMR Spectroscopy to Study Muscle Glycogen Metabolism in Man
Authors: Roden, MD M. , Shulman, MD, PhD G. I.
Published: July 2002

Prior to the advent of nuclear magnetic resonance (NMR) spectroscopy, human glucose metabolism was studied through tracer and tissue biopsy methodology. NMR spectroscopy now provides a noninvasive means to monitor metabolic flux and intracellular metabolite concentrations continuously. 13C NMR spectroscopy has shown that muscle glycogen synthesis accounts for the majority of insulin-stimulated muscle glucose uptake in normal volunteers and that defects in this process are chiefly responsible for insulin resistance in type 1 and type 2 diabetes mellitus, as well as in other insulin resistant states (obesity, insulin-resistant offspring of type 2 diabetic parents, elevation of plasma FFA concentrations). Furthermore, using 31P NMR spectroscopy to measure intracellular glucose-6-phosphate, it has been shown that defects in insulin-stimulated glucose transport/phosphorylation activity are primarily responsible for the insulin resistance in these states.
THE BIOCHEMISTRY AND GENETICS OF CAPSULAR POLYSACCHARIDE PRODUCTION IN BACTERIA
Authors: Roberts Ian S.
Published: July 2002

Bacterial polysaccharides are usually associated with the outer surface of the bacterium. They can form an amorphous layer of extracellular polysaccharide (EPS) surrounding the cell that may be further organized into a distinct structure termed a capsule. Additional polysaccharide molecules such as lipopolysaccharide (LPS) or lipooligosaccharide (LOS) may also decorate the cell surface. Polysaccharide capsules may mediate a number of biological processes, including invasive infections of human beings. Discussed here are the genetics and biochemistry of selected bacterial capsular polysaccharides and the basis of capsule diversity but not the genetics and biochemistry of LPS biosynthesis (for reviews see 100 , 140 ).
Oral Microbial Communities: Biofilms, Interactions, and Genetic Systems
Authors: Kolenbrander Paul E.
Published: July 2002

▪ Abstract  Oral microbial-plaque communities are biofilms composed of numerous genetically distinct types of bacteria that live in close juxtaposition on host surfaces. These bacteria communicate through physical interactions called coaggregation and coadhesion, as well as other physiological and metabolic interactions. Streptococci and actinomyces are the major initial colonizers of the tooth surface, and the interactions between them and their substrata help establish the early biofilm community. Fusobacteria play a central role as physical bridges that mediate coaggregation of cells and as physiological bridges that promote anaerobic microenvironments which protect coaggregating strict anaerobes in an aerobic atmosphere. New technologies for investigating bacterial populations with 16S rDNA probes have uncovered previously uncultured bacteria and have offered an approach to in situ examination of the spatial arrangement of the participant cells in oral-plaque biofilms. Flow cells with saliva-coated surfaces are particularly useful for studies of biofilm formation and observation. The predicted sequential nature of colonization of the tooth surface by members of different genera can be investigated by using these new technologies and imaging the cells in situ with confocal scanning laser microscopy. Members of at least seven genera now can be subjected to genetic studies owing to the discovery of gene-transfer systems in these genera. Identification of contact-inducible genes in streptococci offers an avenue to explore bacterial responses to their environment and leads the way toward understanding communication among inhabitants of a multispecies biofilm.
Quorum Sensing in Bacteria
Authors: Miller Melissa B. , Bassler Bonnie L.
Published: July 2002

▪ Abstract  Quorum sensing is the regulation of gene expression in response to fluctuations in cell-population density. Quorum sensing bacteria produce and release chemical signal molecules called autoinducers that increase in concentration as a function of cell density. The detection of a minimal threshold stimulatory concentration of an autoinducer leads to an alteration in gene expression. Gram-positive and Gram-negative bacteria use quorum sensing communication circuits to regulate a diverse array of physiological activities. These processes include symbiosis, virulence, competence, conjugation, antibiotic production, motility, sporulation, and biofilm formation. In general, Gram-negative bacteria use acylated homoserine lactones as autoinducers, and Gram-positive bacteria use processed oligo-peptides to communicate. Recent advances in the field indicate that cell-cell communication via autoinducers occurs both within and between bacterial species. Furthermore, there is mounting data suggesting that bacterial autoinducers elicit specific responses from host organisms. Although the nature of the chemical signals, the signal relay mechanisms, and the target genes controlled by bacterial quorum sensing systems differ, in every case the ability to communicate with one another allows bacteria to coordinate the gene expression, and therefore the behavior, of the entire community. Presumably, this process bestows upon bacteria some of the qualities of higher organisms. The evolution of quorum sensing systems in bacteria could, therefore, have been one of the early steps in the development of multicellularity.
Advances in the Bacteriology of the Coliform Group: Their Suitability as Markers of Microbial Water Safety
Authors: Leclerc H. , Mossel D. A. A. , Edberg S. C. , Struijk C. B.
Published: July 2002

▪ Abstract  Advances in the elaboration of novel genomic types of β-galactosidase-positive Enterobacteriaceae and comprehensive studies of their habitats have resulted in an innovative approach to the assessment of the merits and shortcomings of the thermotrophic and fecal species Escherichia coli and all other coliforms as markers of the microbiological safety of water. As one of the consequences, it is recommended to abolish the “technical” designation fecal coliforms because their current method of detection will result in the isolation of thermotrophic organisms that have been demonstrated, beyond a doubt, to be of environmental, rather than uniquely enteric origin. Additional population studies have demonstrated that none of the coliforms can function as reliable markers for all enteric pathogens (index organisms sensu Ingram), nor be of use in validating adequate processing for safety of raw water, which represents the indicator function of markers, as defined by Ingram. Future studies along these lines will have to provide the data required to assess the suitability of additional markers for the reliable monitoring of drinking water for microbiological safety.
FEEDBACK: Theory and Accelerator Applications
Authors: Himel T.
Published: July 2002

▪ Abstract  The use of feedback to stabilize the beam and improve the performance of accelerators is becoming more common. The methods used to design the feedback algorithms are introduced and some practical implementation details are described. The design of a PID loop using classical control techniques is covered as is the design of an optimal controller using modern control theory. Some adaptive control techniques are also briefly described. Examples are given of multiple-input-multiple-output loops and of how to handle systems of many interacting feedback loops.
Prospects for Spin Physics at RHIC
Authors: Bunce Gerry , Saito Naohito , Soffer Jacques , Vogelsang Werner
Published: July 2002

▪ Abstract  Colliding beams of 70% polarized protons at up to [Formula: see text] GeV, with high luminosity, L = 2 × 1032cm−2sec−1, will represent a new and unique laboratory for studying the proton. RHIC-Spin will be the first polarized-proton collider and will be capable of copious production of jets, directly produced photons, and W and Z bosons. Features will include direct and precise measurements of the polarization of the gluons and of [Formula: see text], u, and d quarks in a polarized proton. Parity violation searches for physics beyond the standard model will be competitive with unpolarized searches at the Fermilab Tevatron. Transverse spin will explore transversity for the first time, as well as quark-gluon correlations in the proton. Spin dependence of the total cross section and in the Coulomb nuclear interference region will be measured at collider energies for the first time. These qualitatively new measurements can be expected to deepen our understanding of the structure of matter and of the strong interaction.
DEVELOPMENT OF FOOD PREFERENCES
Authors: Birch Leann L.
Published: July 2002

▪ Abstract  Using a developmental systems perspective, this review focuses on how genetic predispositions interact with aspects of the eating environment to produce phenotypic food preferences. Predispositions include the unlearned, reflexive reactions to basic tastes: the preference for sweet and salty tastes, and the rejection of sour and bitter tastes. Other predispositions are (a) the neophobic reaction to new foods and (b) the ability to learn food preferences based on associations with the contexts and consequences of eating various foods. Whether genetic predispositions are manifested in food preferences that foster healthy diets depends on the eating environment, including food availability and child-feeding practices of the adults. Unfortunately, in the United States today, the ready availability of energy-dense foods, high in sugar, fat, and salt, provides an eating environment that fosters food preferences inconsistent with dietary guidelines, which can promote excess weight gain and obesity.
The Clinical Pharmacology of L-Arginine
Authors: Böger Rainer H , Bode-Böger Stefanie M
Published: July 2002

L-Arginine (2-amino-5-guanidinovaleric acid) is the precursor of nitric oxide, an endogenous messenger molecule involved in a variety of endothelium-mediated physiological effects in the vascular system. Acute and chronic administration of L-arginine has been shown to improve endothelial function in animal models of hypercholesterolemia and atherosclerosis. L-Arginine also improves endothelium-dependent vasodilation in humans with hypercholesterolemia and atherosclerosis. The responsiveness to L-arginine depends on the specific cardiovascular disease studied, the vessel segment, and morphology of the artery. The pharmacokinetics of L-arginine have recently been investigated. Side effects are rare and mostly mild and dose dependent. The mechanism of action of L-arginine may involve nitric oxide synthase substrate provision, especially in patients with elevated levels of the endogenous NO synthase inhibitor asymmetric dimethylarginine. Endocrine effects and unspecific reactions may contribute to L-arginine-induced vasodilation after higher doses. Several long-term studies have been performed that show that chronic oral administration of L-arginine or intermittent infusion therapy with L-arginine can improve clinical symptoms of cardiovascular disease in man.
IN MY TIME: Scenes of Scientific Life
Authors: Leach Sydney
Published: July 2002

[Figure: see text]

▪ Abstract  A narrative account of the ingredients in the making of a young scientist, his wartime science in England, and subsequent career in France, where, starting in molecular electronic spectroscopy, he has grown older and has expanded his horizons to address problems of astrophysical, nonlinear optical, and biological interest, using, with the aid of many good scientists, a variety of techniques, mainly of optical and mass spectroscopies and with synchrotron radiation as an important excitation source. He has plans to continue….
THE DYNAMICS OF “STRETCHED MOLECULES”: Experimental Studies of Highly Vibrationally Excited Molecules With Stimulated Emission Pumping
Authors: Silva Michelle , Jongma Rienk , Field Robert W , Wodtke Alec M
Published: July 2002

▪ Abstract  We review stimulated emission pumping as used to study molecular dynamics. The review presents unimolecular as well as scattering studies. Topics include intramolecular vibrational redistribution, unimolecular isomerization and dissociation, van der Waals clusters, rotational energy transfer, vibrational energy transfer, gas-surface interactions, atmospheric effects resulting from nonequilibrium vibrational excitation, and vibrational promotion of electron transfer.
What Do We Know About Democratization After Twenty Years?
Authors: Geddes Barbara
Published: July 2002

This essay synthesizes the results of the large number of studies of late–20th-century democratization published during the last 20 years. Strong evidence supports the claims that democracy is more likely in more developed countries and that regime transitions of all kinds are more likely during economic downturns. Very few of the other arguments advanced in the transitions literature, however, appear to be generally true. This study proposes a theoretical model, rooted in characteristics of different types of authoritarian regimes, to explain many of the differences in democratization experience across cases in different regions. Evidence drawn from a data set that includes 163 authoritarian regimes offers preliminary support for the model proposed.
BARGAININGTHEORY ANDINTERNATIONALCONFLICT
Authors: Powell Robert
Published: July 2002

▪ Abstract  International relations theory has long seen the origins, conduct, and termination of war as a bargaining process. Recent formal work on these issues draws very heavily on Rubinstein's (1982) seminal analysis of the bargaining problem and the research that flowed from it. There is now what might be called a standard or canonical model of the origins of war that sees this outcome as a bargaining breakdown. This essay reviews this standard model and current efforts to extend it to the areas of (a) multilateral bargaining, which is at the heart of old issues such as balancing and bandwagoning as well as newer ones such as the role of third-party mediation; (b) the effects of domestic politics on international outcomes; (c) efforts to explicitly model intra-war bargaining; and (d) dynamic commitment problems.
FAMILIES AS SYSTEMS
Authors: Cox Martha J. , Paley Blair
Published: July 2002

▪ Abstract  In this chapter, we discuss theoretical and conceptual models that use an organismic or systems metaphor for understanding families. We suggest that such theories are important for stimulating new research and organizing existing data, and that advances in these theories over the past few decades have expanded the potential for understanding child development, as well as adult adaptation and the development of close relationships. These paradigms follow from models that view development as resulting from the transactional regulatory processes of dynamic systems. Such models are helpful for considering multiple influences on development and adaptation and have implications for the design of effective interventions. We focus on the specifics of systems theories as applied to families, and the research generated by or consistent with these views. Our review is not exhaustive; rather, we intend to give a sense of the direction of this work and its importance for the understanding of development and adaptation.
ORGANIZATIONAL CHANGE AND DEVELOPMENT
Authors: Weick Karl E. , Quinn Robert E.
Published: July 2002

▪ Abstract  Recent analyses of organizational change suggest a growing concern with the tempo of change, understood as the characteristic rate, rhythm, or pattern of work or activity. Episodic change is contrasted with continuous change on the basis of implied metaphors of organizing, analytic frameworks, ideal organizations, intervention theories, and roles for change agents. Episodic change follows the sequence unfreeze-transition-refreeze, whereas continuous change follows the sequence freeze-rebalance-unfreeze. Conceptualizations of inertia are seen to underlie the choice to view change as episodic or continuous.
Personality
Authors: Funder David C.
Published: July 2002

▪ Abstract  Personality psychology is as active today as at any point in its history. The classic psychoanalytic and trait paradigms are active areas of research, the behaviorist paradigm has evolved into a new social-cognitive paradigm, and the humanistic paradigm is a basis of current work on cross-cultural psychology. Biology and evolutionary theory have also attained the status of new paradigms for personality. Three challenges for the next generation of research are to integrate these disparate approaches to personality (particularly the trait and social-cognitive paradigms), to remedy the imbalance in the person-situation-behavior triad by conceptualizing the basic properties of situations and behaviors, and to add to personality psychology's thin inventory of basic facts concerning the relations between personality and behavior.
Adolescent Development
Authors: Steinberg Laurence , Morris Amanda Sheffield
Published: July 2002

▪ Abstract  This chapter identifies the most robust conclusions and ideas about adolescent development and psychological functioning that have emerged since Petersen's 1988 review. We begin with a discussion of topics that have dominated recent research, including adolescent problem behavior, parent-adolescent relations, puberty, the development of the self, and peer relations. We then identify and examine what seem to us to be the most important new directions that have come to the fore in the last decade, including research on diverse populations, contextual influences on development, behavioral genetics, and siblings. We conclude with a series of recommendations for future research on adolescence.
Human Aggression
Authors: Anderson Craig A. , Bushman Brad J.
Published: July 2002

▪ Abstract  Research on human aggression has progressed to a point at which a unifying framework is needed. Major domain-limited theories of aggression include cognitive neoassociation, social learning, social interaction, script, and excitation transfer theories. Using the general aggression model (GAM), this review posits cognition, affect, and arousal to mediate the effects of situational and personological variables on aggression. The review also organizes recent theories of the development and persistence of aggressive personality. Personality is conceptualized as a set of stable knowledge structures that individuals use to interpret events in their social world and to guide their behavior. In addition to organizing what is already known about human aggression, this review, using the GAM framework, also serves the heuristic function of suggesting what research is needed to fill in theoretical gaps and can be used to create and test interventions for reducing aggression.
REVIEW OF COMMUNITY-BASED RESEARCH: Assessing Partnership Approaches to Improve Public Health
Authors: Israel Barbara A. , Schulz Amy J. , Parker Edith A. , Becker Adam B.
Published: July 2002

▪ Abstract  Community-based research in public health focuses on social, structural, and physical environmental inequities through active involvement of community members, organizational representatives, and researchers in all aspects of the research process. Partners contribute their expertise to enhance understanding of a given phenomenon and to integrate the knowledge gained with action to benefit the community involved. This review provides a synthesis of key principles of community-based research, examines its place within the context of different scientific paradigms, discusses rationales for its use, and explores major challenges and facilitating factors and their implications for conducting effective community-based research aimed at improving the public's health.
Nonstandard Employment Relations: Part-time, Temporary and Contract Work
Authors: Kalleberg Arne L.
Published: July 2002

Nonstandard employment relations—such as part-time work, temporary help agency and contract company employment, short-term and contingent work, and independent contracting—have become increasingly prominent ways of organizing work in recent years. Our understanding of these nonstandard work arrangements has been hampered by inconsistent definitions, often inadequate measures, and the paucity of comparative research. This chapter reviews the emerging research on these nonstandard work arrangements. The review emphasizes the multidisciplinary nature of contributions to this field, including research by a variety of sociologists, economists, and psychologists. It also focuses on cross-national research, which is needed to investigate how macroeconomic, political, and institutional factors affect the nature of employment relations. Areas for future research are suggested.
Birds of a Feather: Homophily in Social Networks
Authors: McPherson Miller , Smith-Lovin Lynn , Cook James M
Published: July 2002

Similarity breeds connection. This principle—the homophily principle—structures network ties of every type, including marriage, friendship, work, advice, support, information transfer, exchange, comembership, and other types of relationship. The result is that people's personal networks are homogeneous with regard to many sociodemographic, behavioral, and intrapersonal characteristics. Homophily limits people's social worlds in a way that has powerful implications for the information they receive, the attitudes they form, and the interactions they experience. Homophily in race and ethnicity creates the strongest divides in our personal environments, with age, religion, education, occupation, and gender following in roughly that order. Geographic propinquity, families, organizations, and isomorphic positions in social systems all create contexts in which homophilous relations form. Ties between nonsimilar individuals also dissolve at a higher rate, which sets the stage for the formation of niches (localized positions) within social space. We argue for more research on: (a) the basic ecological processes that link organizations, associations, cultural communities, social movements, and many other social forms; (b) the impact of multiplex ties on the patterns of homophily; and (c) the dynamics of network change over time through which networks and other social entities co-evolve.
Inhibitory Effects of Protein Kinase C on Inwardly Rectifying K
+
- and ATP-Sensitive K
+
Channel-Mediated Responses of the Basilar Artery
Authors: Chrissobolis Sophocles , Sobey Christopher G.
Published: July 2002

Background and Purpose

—

The structurally related, inwardly rectifying K
+
(K
IR
) channel and the ATP-sensitive K
+
(K
ATP
) channel are important modulators of cerebral artery tone. Although protein kinase C (PKC) activators have been shown to inhibit these channels with the use of patch-clamp electrophysiology, effects of PKC on K
+
channel function in intact cerebral blood vessels are unknown. We therefore tested whether pharmacological alteration of PKC activity affects cerebral vasodilator responses to K
IR
and/or K
ATP
channel activators in vivo.

Methods

—

We measured changes in basilar artery diameter using a cranial window preparation in anesthetized rats. In addition, intracellular recordings of smooth muscle membrane potential were made in isolated basilar arteries.

Results

—

K
+
(5 to 15 mmol/L) and aprikalim (1 to 10 μmol/L) each elicited reproducible vasodilatation. The PKC activator phorbol-12,13-dibutyrate (PdBu) (50 nmol/L) inhibited responses to K
+
(by 40% to 55%) and aprikalim (by 40% to 70%), whereas responses to papaverine were unaffected. The PKC inhibitor calphostin C (0.1 μmol/L) augmented responses to K
+
(by 2- to 3-fold) and aprikalim (2-fold) but not papaverine. In addition, K
+
(5 mmol/L) and aprikalim (3 μmol/L) each hyperpolarized the basilar artery. PdBu inhibited these responses to aprikalim by 45% but had no effect on K
+
-induced hyperpolarization.

Conclusions

—

These data suggest that both basal and stimulated PKC activity inhibit K
IR
and K
ATP
channel–mediated cerebral vasodilatation in vivo. The inhibitory effect on K
ATP
channel–mediated vasodilatation occurs at least partly by inhibition of hyperpolarization mediated by K
ATP
channels. PKC inhibits K
+
-induced vasodilatation without affecting hyperpolarization, suggesting that the inhibitory effect of PKC on vasodilator responses to K
+
does not involve altered K
IR
channel function.
The Critical Barrier to Civil War Settlement
Authors: Walter Barbara F.
Published: July 2002

Unlike interstate wars, civil wars rarely end in negotiated settlements. Between 1940 and 1990 55 percent of interstate wars were resolved at the bargaining table, whereas only 20 percent of civil wars reached similar solutions. Instead, most internal wars ended with the extermination, expulsion, or capitulation of the losing side. In fact, groups fighting civil wars almost always chose to fight to the finish unless an outside power stepped in to guarantee a peace agreement. If a third party agreed to enforce the terms of a peace treaty, negotiations always succeeded regardless of the initial goals, ideology, or ethnicity of the participants. If a third party did not intervene, these talks usually failed.
Learning Methods to Combine Linguistic Indicators: Improving Aspectual Classification and Revealing Linguistic Insights
Authors: Siegel Eric V. , McKeown Kathleen R.
Published: July 2002

Aspectual classification maps verbs to a small set of primitive categories in order to reason about time. This classification is necessary for interpreting temporal modifiers and assessing temporal relationships, and is therefore a required component for many natural language applications.

A verb's aspectual category can be predicted by co-occurrence frequencies between the verb and certain linguistic modifiers. These frequency measures, called linguistic indicators, are chosen by linguistic insights. However, linguistic indicators used in isolation are predictively incomplete, and are therefore insufficient when used individually.

In this article, we compare three supervised machine learning methods for combining multiple linguistic indicators for aspectual classification: decision trees, genetic programming, and logistic regression. A set of 14 indicators are combined for classification according to two aspectual distinctions. This approach improves the classification performance for both distinctions, as evaluated over unrestricted sets of verbs occurring across two corpora. This demonstrates the effectiveness of the linguistic indicators and provides a much-needed full-scale method for automatic aspectual classification. Moreover, the models resulting from learning reveal several linguistic insights that are relevant to aspectual classification. We also compare supervised learning methods with an unsupervised method for this task.
Bounds on Error Expectation for Support Vector Machines
Authors: Vapnik V. , Chapelle O.
Published: July 2002

We introduce the concept of span of support vectors (SV) and show that the generalization ability of support vector machines (SVM) depends on this new geometrical concept. We prove that the value of the span is always smaller (and can be much smaller) than the diameter of the smallest sphere containing the support vectors, used in previous bounds (Vapnik, 1998). We also demonstate experimentally that the prediction of the test error given by the span is very accurate and has direct application in model selection (choice of the optimal parameters of the SVM).
Estimating the Support of a High-Dimensional Distribution
Authors: Schölkopf Bernhard , Platt John C. , Shawe-Taylor John , Smola Alex J. , Williamson Robert C.
Published: July 2002

Suppose you are given some data set drawn from an underlying probability distribution P and you want to estimate a “simple” subset S of input space such that the probability that a test point drawn from P lies outside of S equals some a priori specified value between 0 and 1.

We propose a method to approach this problem by trying to estimate a function f that is positive on S and negative on the complement. The functional form of f is given by a kernel expansion in terms of a potentially small subset of the training data; it is regularized by controlling the length of the weight vector in an associated feature space. The expansion coefficients are found by solving a quadratic programming problem, which we do by carrying out sequential optimization over pairs of input patterns. We also provide a theoretical analysis of the statistical performance of our algorithm.

The algorithm is a natural extension of the support vector algorithm to the case of unlabeled data.
Mechanisms Shaping Fast Excitatory Postsynaptic Currents in the Central Nervous System
Authors: Glavinović Mladen I.
Published: July 2002

How different factors contribute to determine the time course of the basic element of fast glutamate-mediated excitatory postsynaptic currents (mEPSCs) in the central nervous system has been a focus of interest of neurobiologists for some years. In spite of intensive investigations, these mechanisms are not well understood. In this review, basic hypotheses are summarized, and a new hypothesis is proposed, which holds that desensitization of AMPA receptros plays a major role in shaping the time course of fast mEPSCs. According to the new hypothesis, desensitization shortens the time course of mEPSCs largely by reducing the buffering of glutamate molecules by AMPA receptors. The hypothesis accounts for numerous findings on fast mEPSCs and is expected to be equally fruitful as a framework for further experimental and theoretical investigations.
Neural Network Pruning with Tukey-Kramer Multiple Comparison Procedure
Authors: Duckro Donald E. , Quinn Dennis W. , Gardner Samuel J.
Published: July 2002

Reducing a neural network's complexity improves the ability of the network to generalize future examples. Like an overfitted regression function, neural networks may miss their target because of the excessive degrees of freedom stored up in unnecessary parameters. Over the past decade, the subject of pruning networks produced nonstatistical algorithms like Skeletonization, Optimal Brain Damage, and Optimal Brain Surgeon as methods to remove connections with the least salience. The method proposed here uses the bootstrap algorithm to estimate the distribution of the model parameter saliences. Statistical multiple comparison procedures are then used to make pruning decisions. We show this method compares well with Optimal Brain Surgeon in terms of ability to prune and the resulting network performance.
Kernel-Based Equiprobabilistic Topographic Map Formation
Authors: Hulle Marc M. Van
Published: July 2002

We introduce a new unsupervised competitive learning rule, the kernel-based maximum entropy learning rule (kMER), which performs equiprobabilistic topographic map formation in regular, fixed-topology lattices, for use with nonparametric density estimation as well as nonparametric regression analysis. The receptive fields of the formal neurons are overlapping radially symmetric kernels, compatible with radial basis functions (RBFs); but unlike other learning schemes, the radii of these kernels do not have to be chosen in an ad hoc manner: the radii are adapted to the local input density, together with the weight vectors that define the kernel centers, so as to produce maps of which the neurons have an equal probability to be active (equiprobabilistic maps). Both an “online” and a “batch” version of the learning rule are introduced, which are applied to nonparametric density estimation and regression, respectively. The application envisaged is blind source separation (BSS) from nonlinear, noisy mixtures.
Modeling and Prediction of Human Behavior
Authors: Pentland Alex , Liu Andrew
Published: July 2002

We propose that many human behaviors can be accurately described as a set of dynamic models (e.g., Kalman filters) sequenced together by a Markov chain. We then use these dynamic Markov models to recognize human behaviors from sensory data and to predict human behaviors over a few seconds time. To test the power of this modeling approach, we report an experiment in which we were able to achieve 95% accuracy at predicting automobile drivers' subsequent actions from their initial preparatory movements.
Hijikata Tatsumi Chronology
Authors: Nanako Kurihara
Published: July 2002

For the first time in English, we present many of Hijikata's aesthetic and poetic texts. These texts are put into context by Kurihara Nanako's introductory essay. The section includes an interview with Hijikata and a conversation between Hijikata and Japanese experimental theatre innovator Suzuki Tadashi.
A Conceptual Model of the Sense of Presence in Virtual Environments
Authors: Bystrom Karl-Erik , Barfield Woodrow , Hendrix Claudia
Published: July 2002

This paper proposes a model of interaction in virtual environments which we term the immersion, presence, performance (IPP) model. This model is based on previous models of immersion and presence proposed by Barfield and colleagues and Slater and colleagues. The IPP model describes the authors' current conceptualization of the effects of display technology, task demands, and attentional resource allocation on immersion, presence, and performance in virtual environments. The IPP model may be useful for developing a theoretical framework for research on presence and for interpreting the results of empirical studies on the sense of presence in virtual environments. The model may also be of interest to designers of virtual environments.
Ant Algorithms for Discrete Optimization
Authors: Dorigo Marco , Caro Gianni Di , Gambardella Luca M.
Published: July 2002

This article presents an overview of recent work on ant algorithms, that is, algorithms for discrete optimization that took inspiration from the observation of ant colonies' foraging behavior, and introduces the ant colony optimization (ACO) metaheuristic. In the first part of the article the basic biological findings on real ants are reviewed and their artificial counterparts as well as the ACO metaheuristic are defined. In the second part of the article a number of applications of ACO algorithms to combinatorial optimization and routing in communications networks are described. We conclude with a discussion of related work and of some of the most important aspects of the ACO metaheuristic.
THE DAUGHTER, THE SINGING-GIRL, AND THE SEDUCTION OF SUICIDE
Authors: Carlitz Katherine
Published: July 2002

This paper examines how the suicides of singing-girls and young gentry women were commemorated by the poets Kang Hai (1475-1541) and Wang Jiusi (1468- 1551) whose devotion to wine, women, and song were, and still are, legendary. Witnessing the suicides of mutually-related female family members as well as a concubine of a mutual friend, these two poets valorized these deaths in terms of qing (passion). The girls of good family defy their elders in order to consummate their suicides, and Wang's songs for the concubine singing-girl are filled with evocations of sensual satisfaction. Thus, in the writings of Kang and Wang we see how the norms of the chastity cult were made not restrictive but alluring; the author suggests that this helped the poets to conquer the imagination of the governing class, with the ultimate results that they were able to diffuse these images throughout the whole of society.
CHARTING CULTURAL VARIATION IN CHIMPANZEES
Authors: Whiten  , Goodall  , McGrew W.C. , Nishida  , Reynolds  , Sugiyama  , Tutin C.E.G. , Wrangham R.W. , Boesch
Published: July 2002

Cultural variation among chimpanzee communities or unit-groups at nine long-term study sites was charted through a systematic, collaborative procedure in which the directors of the sites first agreed a candidate list of 65 behaviour patterns (here fully defined), then classified each pattern in relation to its local frequency of occurrence. Thirty-nine of the candidate behaviour patterns were discriminated as cultural variants, sufficiently frequent at one or more sites to be consistent with social transmission, yet absent at one or more others where environmental explanations were rejected. Each community exhibited a unique and substantial profile of such variants, far exceeding cultural variation reported before for any other non-human species. Evaluation of these pan-African distributions against three models for the diffusion of traditions identified multiple cases consistent with cultural evolution involving differentiation in form, function and targets of behaviour patterns.
Molecular characterisation of 18 Pratylenchus species using rDNA Restriction Fragment Length Polymorphism
Authors: Waeyenberge Lieven , Ryss Alexander , Moens Maurice , Pinochet Jorge , Vrain Thierry
Published: July 2002

The RFLP technique was used to establish a reliable diagnostic method for 18 Pratylenchus species: Pratylenchus agilis, P. bolivianus, P. brachyurus, P. coffeae, P. crenatus, P. fallax, P. goodeyi, P. loosi, P. mediterraneus, P. neglectus, P. penetrans, P. pratensis, P. pseudocoffeae, P. scribneri, P. subranjani, P. thornei, P. vulnus and P. zeae. The polymerase chain reaction (PCR) amplified the ITS regions from all species and populations examined and revealed large differences in length, ranging in size from approximately 900 to 1250 bp. The rDNA fragments were digested with five restriction enzymes (CfoI, DdeI, HindIII, HpaII, and PstI). All Pratylenchus species can be differentiated from each other by a combination of at least two enzymes. CfoI differentiated all nematode species with the exception of P. fallax, P. penetrans and P. pseudocoffeae. P. fallax was further separated by a DdeI restriction, and P. pseudocoffeae by a PstI digestion. Intraspecific RFLP were observed. Upon CfoI, DdeI, HindIII, or HpaII digestion, it was possible to separate the three P. coffeae populations studied from each other. La technique RFLP a été utilisée pour créer une méthode fiable de diagnostic pour 18 espèces de Pratylenchus: Pratylenchus agilis, P. bolivianus, P. brachyurus, P. coffeae, P. crenatus, P. fallax, P. goodeyi, P. loosi, P. mediterraneus, P. neglectus, P. penetrans, P. pratensis, P. pseudocoffeae, P. scribneri, P. subranjani, P. thornei, P. vulnus et P. zeae. La réaction de polymérisation en chaîne (PCR) a amplifié les régions de l’ITS pour toutes les espèces et populations étudiées et a mis en évidence de grandes différences dans la taille des gammes de longueur, de 900 à 1250 bp approximativement. Les fragments de rDNA ont été digérés à l’aide de cinq enzymes de restriction (CfoI, DdeI, HindIII, HpaII, and PstI). Toutes les espèces de Pratylenchus ont pu être différenciées les unes des autres par une combinaison d’au moins deux enzymes. CfoI a différencié toutes les espèces à l’exception de P. fallax, P. penetrans et P. pseudocoffeae. P. fallax a été ultérieurement séparé par une restriction DdeI, et P. pseudocoffeae par une digestion PstI. Des RFLP intraspécifiques ont été observés. Par les digestions CfoI, DdeI, HindIII, ou HpaII, il s’est révélé possible de séparer les unes des autres les trois populations étudiées de P. coffeae.
Rapid and sensitive identification of Pratylenchus spp. using reverse dot blot hybridization
Authors: Uehara Taketo , Kushida Atsuhiko , Momota Yoji
Published: July 2002

A reverse dot blot assay for identification of Pratylenchus spp. has been developed using specific oligonucleotides designed from the sequence of the internal transcribed spacer (ITS) region. The reverse dot blot is a technique which can be especially used for the simultaneous identification of various bacteria. The target fragment was amplified, and labelled with digoxigenine by a polymerase chain reaction (PCR). The amplified fragment was hybridised with the membrane-immobilised oligonucleotide and the hybridization was detected non-radioactively. By this assay, it was possible to identify P. penetrans, P. coffeae, P. vulnus, P. loosi, P. brachyurus, P. crenatus and P. zeae in a single hybridization. Identification rapide et fiable de Pratylenchus spp. a l'aide de l'hybridation retro dot blot - Une technique retro dot blot pour l'identification de Pratylenchus spp. a ete mise au point en utilisant des oligonucleotides specifiques derives de la sequence de l'espaceur transcrit interne (ITS). La technique dot blot est une technique qui peut etre specialement utilisee pour l'identification simultanee de nombreuses bacteries. Le fragment cible a ete amplifie et marque par la digoxigenine a l'aide de la reaction de polymerisation en chaine (PCR). Le fragment amplifie a ete hybride avec l'oligonucleotide immobilise par membrane et l'hybridation detectee non-radioactivement. Grace a cette technique, il a ete possible d'identifier P. penetrans, P. coffeae, P. vulnus, P. loosi, P. brachyurus, P. crenatus et P. zeae en une seule hybridation.