bluuebunny/crossref_metadata_2025 huggingface dataset:
Dialogue Act Modeling for Automatic Tagging and Recognition of Conversational Speech
Authors: Stolcke Andreas , Ries Klaus , Coccaro Noah , Shriberg Elizabeth , Bates Rebecca , Jurafsky Daniel , Taylor Paul , Martin Rachel , Ess-Dykema Carol Van , Meteer Marie
Published: July 2002

We describe a statistical approach for modeling dialogue acts in conversational speech, i.e., speech-act-like units such as STATEMENT, Question, BACKCHANNEL, Agreement, Disagreement, and Apology. Our model detects and predicts dialogue acts based on lexical, collocational, and prosodic cues, as well as on the discourse coherence of the dialogue act sequence. The dialogue model is based on treating the discourse structure of a conversation as a hidden Markov model and the individual dialogue acts as observations emanating from the model states. Constraints on the likely sequence of dialogue acts are modeled via a dialogue act n-gram. The statistical dialogue grammar is combined with word n-grams, decision trees, and neural networks modeling the idiosyncratic lexical and prosodic manifestations of each dialogue act. We develop a probabilistic integration of speech recognition with dialogue modeling, to improve both speech recognition and dialogue act classification accuracy. Models are trained and evaluated using a large hand-labeled database of 1,155 conversations from the Switchboard corpus of spontaneous human-to-human telephone speech. We achieved good dialogue act labeling accuracy (65% based on errorful, automatically recognized words and prosody, and 71% based on word transcripts, compared to a chance baseline accuracy of 35% and human accuracy of 84%) and a small reduction in word recognition error.
Activation in Human MT/MST by Static Images with Implied Motion
Authors: Kourtzi Zoe , Kanwisher Nancy
Published: July 2002

A still photograph of an object in motion may convey dynamic information about the position of the object immediately before and after the photograph was taken (implied motion). Medial temporal/medial superior temporal cortex (MT/MST) is one of the main brain regions engaged in the perceptual analysis of visual motion. In two experiments we examined whether MT/MST is also involved in representing implied motion from static images. We found stronger functional magnetic resonance imaging (fMRI) activation within MT/MST during viewing of static photographs with implied motion compared to viewing of photographs without implied motion. These results suggest that brain regions involved in the visual analysis of motion are also engaged in processing implied dynamic information from static images.
Formation of Direction Selectivity in Natural Scene Environments
Authors: Blais Brian , Cooper Leon N. , Shouval Harel
Published: July 2002

Most simple and complex cells in the cat striate cortex are both orientation and direction selective. In this article we use single-cell learning rules to develop both orientation and direction selectivity in a natural scene environment. We show that a simple principal component analysis rule is inadequate for developing direction selectivity, but that the BCM rule as well as similar higher-order rules can. We also demonstrate that the convergence of lagged and nonlagged cells depends on the velocity of motion in the environment, and that strobe rearing disrupts this convergence, resulting in a loss of direction selectivity.
A Neural Network Architecture for Visual Selection
Authors: Amit Yali
Published: July 2002

This article describes a parallel neural net architecture for efficient and robust visual selection in generic gray-level images. Objects are represented through flexible star-type planar arrangements of binary local features which are in turn star-type planar arrangements of oriented edges. Candidate locations are detected over a range of scales and other deformations, using a generalized Hough transform. The flexibility of the arrangements provides the required invariance. Training involves selecting a small number of stable local features from a predefined pool, which are well localized on registered examples of the object. Training therefore requires only small data sets. The parallel architecture is constructed so that the Hough transform associated with any object can be implemented without creating or modifying any connections. The different object representations are learned and stored in a central module. When one of these representations is evoked, it “primes” the appropriate layers in the network so that the corresponding Hough transform is computed. Analogies between the different layers in the network and those in the visual system are discussed. Furthermore, the model can be used to explain certain experiments on visual selection reported in the literature.
An Amplitude Equation Approach to Contextual Effects in Visual Cortex
Authors: Bressloff Paul C. , Cowan Jack D.
Published: July 2002

A mathematical theory of interacting hypercolumns in primary visual cortex (V1) is presented that incorporates details concerning the anisotropic nature of long-range lateral connections. Each hypercolumn is modeled as a ring of interacting excitatory and inhibitory neural populations with orientation preferences over the range 0 to 180 degrees. Analytical methods from bifurcation theory are used to derive nonlinear equations for the amplitude and phase of the population tuning curves in which the effective lateral interactions are linear in the amplitudes. These amplitude equations describe how mutual interactions between hypercolumns via lateral connections modify the response of each hypercolumn to modulated inputs from the lateral geniculate nucleus; such interactions form the basis of contextual effects. The coupled ring model is shown to reproduce a number of orientation-dependent and contrast-dependent features observed in center-surround experiments. A major prediction of the model is that the anisotropy in lateral connections results in a nonuniform modulatory effect of the surround that is correlated with the orientation of the center.
Slow Feature Analysis: Unsupervised Learning of Invariances
Authors: Wiskott Laurenz , Sejnowski Terrence J.
Published: July 2002

Invariant features of temporally varying signals are useful for analysis and classification. Slow feature analysis (SFA) is a new method for learning invariant or slowly varying features from a vectorial input signal. It is based on a nonlinear expansion of the input signal and application of principal component analysis to this expanded signal and its time derivative. It is guaranteed to find the optimal solution within a family of functions directly and can learn to extract a large number of decor-related features, which are ordered by their degree of invariance. SFA can be applied hierarchically to process high-dimensional input signals and extract complex features. SFA is applied first to complex cell tuning properties based on simple cell output, including disparity and motion. Then more complicated input-output functions are learned by repeated application of SFA. Finally, a hierarchical network of SFA modules is presented as a simple model of the visual system. The same unstructured network can learn translation, size, rotation, contrast, or, to a lesser degree, illumination invariance for one-dimensional objects, depending on only the training stimulus. Surprisingly, only a few training objects suffice to achieve good generalization to new objects. The generated representation is suitable for object recognition. Performance degrades if the network is trained to learn multiple invariances simultaneously.
Antipredictable Sequences: Harder to Predict Than Random Sequences
Authors: Zhu Huaiyu , Kinzel Wolfgang
Published: July 2002

For any discrete-state sequence prediction algorithm A, it is always possible, using an algorithm B no more complicated than A, to generate a sequence for which A's prediction is always wrong. For any prediction algorithm A and sequence x, there exists a sequence y no more complicated than x, such that if A performs better than random on x, then it will perform worse than random on y by the same margin. An example of a simple neural network predicting a bit sequence is used to illustrate this very general but not widely recognized phenomenon. This implies that any predictor with good performance must rely on some (usually implicitly) assumed prior distributions of the problem.
Classification of Temporal Patterns in Dynamic Biological Networks
Authors: Roberts Patrick D.
Published: July 2002

A general method is presented to classify temporal patterns generated by rhythmic biological networks when synaptic connections and cellular properties are known. The method is discrete in nature and relies on algebraic properties of state transitions and graph theory. Elements of the set of rhythms generated by a network are compared using a metric that quantifies the functional differences among them. The rhythms are then classified according to their location in a metric space. Examples are given, and biological implications are discussed.
Dynamics of Membrane Excitability Determine Interspike Interval Variability: A Link Between Spike Generation Mechanisms and Cortical Spike Train Statistics
Authors: Gutkin Boris S. , Ermentrout G. Bard
Published: July 2002

We propose a biophysical mechanism for the high interspike interval variability observed in cortical spike trains. The key lies in the nonlinear dynamics of cortical spike generation, which are consistent with type I membranes where saddle-node dynamics underlie excitability (Rinzel & Ermentrout, 1989). We present a canonical model for type I membranes, the θ-neuron. The θ-neuron is a phase model whose dynamics reflect salient features of type I membranes. This model generates spike trains with coefficient of variation (CV) above 0.6 when brought to firing by noisy inputs. This happens because the timing of spikes for a type I excitable cell is exquisitely sensitive to the amplitude of the suprathreshold stimulus pulses. A noisy input current, giving random amplitude “kicks” to the cell, evokes highly irregular firing across a wide range of firing rates; an intrinsically oscillating cell gives regular spike trains. We corroborate the results with simulations of the Morris-Lecar (M-L) neural model with random synaptic inputs: type I M-L yields high CVs. When this model is modified to have type II dynamics (periodicity arises via a Hopf bifurcation), however, it gives regular spike trains (CV below 0.3). Our results suggest that the high CV values such as those observed in cortical spike trains are an intrinsic characteristic of type I membranes driven to firing by “random” inputs. In contrast, neural oscillators or neurons exhibiting type II excitability should produce regular spike trains.
Absence of Cycles in Symmetric Neural Networks
Authors: Wang Xin , Jagota Arun , Botelho Fernanda , Garzon Max
Published: July 2002

For a given recurrent neural network, a discrete-time model may have asymptotic dynamics different from the one of a related continuous-time model. In this article, we consider a discrete-time model that discretizes the continuous-time leaky integrat or model and study its parallel, sequential, block-sequential, and distributed dynamics for symmetric networks. We provide sufficient (and in many cases necessary) conditions for the discretized model to have the same cycle-free dynamics of the corresponding continuous-time model in symmetric networks.
Inferring Perceptual Saliency Fields from Viewpoint-Dependent Recognition Data
Authors: Cutzu Florin , Tarr Michael
Published: July 2002

We present an algorithm for computing the relative perceptual saliencies of the features of a three-dimensional object using either goodness-of-view scores measured at several viewpoints or perceptual similarities among several object views. This technique addresses the inverse, illposed version of the direct problem of predicting goodness-of-view scores or view point similarities when the object features are known. On the basis of a linear model for the direct problem, we solve the inverse problem using the method of regularization. The critical assumption we make to regularize the solution is that perceptual salience varies slowly on the surface of the object. The salient regions derived using this assumption empirically indicate what object structures are important in human three-dimensional object perception, a domain where theories typically have been based on somewhat ad hoc features.
Algorithmic Stability and Sanity-Check Bounds for Leave-One-Out Cross-Validation
Authors: Kearns Michael , Ron Dana
Published: July 2002

In this article we prove sanity-check bounds for the error of the leave-oneout cross-validation estimate of the generalization error: that is, bounds showing that the worst-case error of this estimate is not much worse than that of the training error estimate. The name sanity check refers to the fact that although we often expect the leave-one-out estimate to perform considerably better than the training error estimate, we are here only seeking assurance that its performance will not be considerably worse. Perhaps surprisingly, such assurance has been given only for limited cases in the prior literature on cross-validation.

Any nontrivial bound on the error of leave-one-out must rely on some notion of algorithmic stability. Previous bounds relied on the rather strong notion of hypothesis stability, whose application was primarily limited to nearest-neighbor and other local algorithms. Here we introduce the new and weaker notion of error stability and apply it to obtain sanity-check bounds for leave-one-out for other classes of learning algorithms, including training error minimization procedures and Bayesian algorithms. We also provide lower bounds demonstrating the necessity of some form of error stability for proving bounds on the error of the leave-one-out estimate, and the fact that for training error minimization algorithms, in the worst case such bounds must still depend on the Vapnik-Chervonenkis dimension of the hypothesis class.
Analog Neural Nets with Gaussian or Other Common Noise Distributions Cannot Recognize Arbitrary Regular Languages
Authors: Maass Wolfgang , Sontag Eduardo D.
Published: July 2002

We consider recurrent analog neural nets where the output of each gate is subject to gaussian noise or any other common noise distribution that is nonzero on a sufficiently large part of the state-space. We show that many regular languages cannot be recognized by networks of this type, and we give a precise characterization of languages that can be recognized. This result implies severe constraints on possibilities for constructing recurrent analog neural nets that are robust against realistic types of analog noise. On the other hand, we present a method for constructing feedfor-ward analog neural nets that are robust with regard to analog noise of this type.
Reunion: John Cage, Marcel Duchamp, Electronic Music and Chess
Authors: Cross Lowell
Published: July 2002

The author chronicles his involvement in Reunion, a 1968 collaborative performance featuring John Cage, Marcel Duchamp and Teeny Duchamp, with electronic music by David Behrman, Gordon Mumma, David Tudor and Lowell Cross. After addressing some misconceptions about Reunion, the author outlines specific details about the conditions surrounding the performance and the sound-distributing chessboard he built, then offers an interpretation of the event.
Effects of Characteristics of Image Quality in an Immersive Environment
Authors: Duh Henry Been-Lirn , Lin James J. W. , Kenyon Robert V. , Parker Donald E. , Furness Thomas A.
Published: July 2002

Image quality issues such as field of view (FOV) and resolution are important for evaluating “presence” and simulator sickness (SS) in virtual environments (VEs). This research examined effects on postural stability of varying FOV, image resolution, and scene content in an immersive visual display. Two different scenes (a photograph of a fountain and a simple radial pattern) at two different resolutions were tested using six FOVs (30, 60, 90, 120, 150, and 180 deg.). Both postural stability, recorded by force plates, and subjective difficulty ratings varied as a function of FOV, scene content, and image resolution. Subjects exhibited more balance disturbance and reported more difficulty in maintaining posture in the wide-FOV, highresolution, and natural scene conditions.
Real-Time Continuous Multiresolution Method for Models of Arbitrary Topology
Authors: Lau Rynson W.H. , Green Mark , To Danny , Wong Janis
Published: July 2002

Many multiresolution methods have been proposed. Most of them emphasize accuracy and hence are slow. Some methods may be fast, but they may not preserve the geometry of the model. Although there are a few real-time multiresolution methods available, they are developed mainly for handling large terrain models. In this paper, we present a very efficient multiresolution method for continuously reducing the resolution of a triangle model by incrementally removing triangles from it. The algorithm is simple to implement, requires no complicated data structures, and has a linear triangle deletion rate. We also present a method for caching the most recent sequence of triangle removal operations into a list, called the simplification list, so that it is possible to continuously increase the resolution of the model by inserting triangles in the reverse order of the sequence. We will compare our method with Hoppe's progressive meshes. Towards the end of the paper, we discuss the performance and memory usage of our method.
Virtual Eyes Can Rearrange Your Body: Adaptation to Visual Displacement in See-Through, Head-Mounted Displays
Authors: Biocca Frank A. , Rolland J.P.
Published: July 2002

Among the most critical issues in the design of immersive virtual environments are those that deal with the problem of technologically induced intersensory conflict and one of the results, sensorimotor adaptation. An experiment was conducted to support the design of a prototype see-through, head-mounted display (HMD). When wearing video see-through HMDs in augmented reality systems, subjects see the world around them through a pair of head-mounted video cameras. The study looked at the effects of sensory rearrangement caused by a HMD design that displaced the user's “virtual” eye position forward (165 mm) and above (62 mm) toward the spatial position of the cameras. The position of the cameras creates images of the world that are slightly downward and inward from normal. Measures of hand-eye coordination and speed on a manual pegboard task revealed substantial perceptual costs of the eye displacement initially, but also evidence of adaptation. Upon first wearing the video see-through HMD, subjects' pointing errors increased significantly along the spatial dimensions displaced (the y dimension, above-below the target, and z dimension, in front-behind the target). Speed of performance on the pegboard task decreased by 43% compared to baseline performance. Pointing accuracy improved by approximately 33% as subjects adapted to the sensory rearrangement, but it did not reach baseline performance. When subjects removed the see-through HMD, there was evidence that their hand-eye coordination had been altered. Negative aftereffects were observed in the form of greater errors in pointing accuracy compared to baseline. Although these aftereffects are temporary, the results may have serious practical implications for the use of video see-through HMDs by users (e.g., surgeons) who depend on very accurate hand-eye coordination.
Self-Evolution in a Constructive Binary String System
Authors: Dittrich Peter , Banzhaf Wolfgang
Published: July 2002

We examine the qualitative dynamics of a catalytic self-organizing system of binary strings that is inspired by the chemical information processing metaphor. A string is interpreted in two different ways: either (a) as raw data or (b) as a machine that is able to process another string as data in order to produce a third one. This article focuses on the phenomena of evolution whose appearance is notable because no explicit mutation, recombination, or artificial selection operators are introduced. We call the system self-evolving because every variation is performed by the objects themselves in their machine form.
Self-Replicating and Self-Repairing Multicellular Automata
Authors: Tempesti Gianluca , Mange Daniel , Stauffer André
Published: July 2002

Biological organisms are among the most intricate structures known to man, exhibiting highly complex behavior through the massively parallel cooperation of numerous relatively simple elements, the cells. As the development of computing systems approaches levels of complexity such that their synthesis begins to push the limits of human intelligence, engineers are starting to seek inspiration in nature for the design of computing systems, both at the software and at the hardware levels. We present one such endeavor, notably an attempt to draw inspiration from biology in the design of a novel digital circuit: a field-programmable gate array (FPGA). This reconfigurable logic circuit will be endowed with two features motivated and guided by the behavior of biological systems: self-replication and self-repair.
Book
Authors: Steinfeld Jeffrey I.
Published: July 2002

Green Chemistry: Theory and Practice, by Paul T. Anastas and John C. Warner

Green Chemistry: Frontiers in Benign Chemical Synthesis and Processes, ed. by Paul T. Anastas and Tracy C. Williamson

Green Chemistry: Designing Chemistry for the Environment, ed. by Paul T. Anastas and Tracy C. Williamson
Consumption and Environment in a Global Economy
Authors: Conca Ken
Published: July 2002

Economic globalization demands two important adjustments in how we understand and undertake efforts to protect the global environment. One critical but overlooked effect of globalization is its impact on the “sustaining middle”—the large but fragile stratum of the Earth's population that lives, works, and consumes in ways most closely approximating genuine sustainability. Although we tend to view the world in dichotomous North/South terms, perhaps the greatest challenge of global environmental protection is to stem the corrosive effects of globalization on both ends of this middle stratum. Second, we must understand and respond to the ways that globalization undermines traditional regulatory approaches to environmental protection. Power in global production systems has shifted both upstream and downstream from the factory floor, where environmental efforts traditionally have focused. Viewing the problem from the consumption angle calls attention to the importance of following economic power “downstream” in global commodity chains, to the ideologies, symbols, relationships and practices that drive consumption.
A Comparative Look at NGO Influence in International Environmental Negotiations: Desertification and Climate Change
Authors: Corell Elisabeth , Betsill Michele M.
Published: July 2002

There is a need to better understand the significance of NGOs in global environmental politics. Addressing a number of weaknesses in the current literature on NGOs, we have developed an analytical framework for analysis of NGO influence in international environmental negotiations. This paper demonstrates the utility of our framework by applying it to two cases: the negotiations of the Desertification Convention and of the Kyoto Protocol to the Climate Change Convention. We argue that the use of our research framework enables researchers to compare with confidence NGO influence across cases and that such comparison allows for a much needed examination of factors that explain variation in NGO influence in international environmental negotiations. Analysis of explanatory factors contributes to an improved understanding of the degree to which NGOs matter in global environmental policy-making.
Did Plotinus and Porphyry disagree on Aristotle's Categories?
Authors: De Haas Frans
Published: July 2002

In this paper I propose a reading of Plotinus Enneads VI.1-3 \[41-43] On the genera of being which regards this treatise as a coherent whole in which Aristotle's Categories is explored in a way that turns it into a decisive contribution to Plotinus' Platonic ontology. In addition, I claim that Porphyry's Isagoge and commentaries on the Categories start by adopting Plotinus' point of view, including his notion of genus, and proceed by explaining its consequences for a more detailed reading of the Categories. After Plotinus' integration of the Categories into the Platonic frame of thought Porphyry saw the possibilities of exploiting the Peripatetic tradition both as a means to support the Platonic interpretation of the Categories and as a source for solutions to traditional questions. His allegiance to a division of being into ten, and his emphasis on semantics rather than ontology can be explained from this orientation. In the light of our investigation the alleged disagreement between Plotinus and Porphyry on the Categories changes its appearance completely. There are differences, but these can be best explained as confirmation and extension of Plotinus' perspective on the Categories and its role in Platonism.
A LONG-TERM STUDY OF A SHORT-LIVED FISH: THE DEMOGRAPHY OF GASTEROSTEUS ACULEATUS
Authors: Wootton R.J. , Smith
Published: July 2002

(1) We present the results of the first long-term investigation on the demography of a population of three-spined sticklebacks. This study describes the changes in the abundance of a population from a backwater of the Afon Rheidol in mid-Wales, based on mark-recapture data collected in October of each year from 1972 until 1998. (2) The population showed quasi-cyclical changes in abundance around a trend line with a period of approximately 6 years. Over the duration of the study there was a tendency for the population to decline. During the unusually dry summers of 1976, 1983, 1984 and 1989 the population was either at a minimum size or was below the estimated trend line. Estimates of stickleback densities varied between 7-28 m-2. (3) Analysis of length-frequency data showed there were two cohorts present. These were assumed to represent two age classes, 0+ and 1+ , with the population consisting largely of the 0+ class. Thus the population was essentially annual. (4) There was evidence of density-dependent mortality and growth of 0+ sticklebacks during and shortly after the spawning period.
THE PIVOTAL ROLE OF RANK IN GROOMING AND SUPPORT BEHAVIOR IN A CAPTIVE GROUP OF BONOBOS (PAN PANISCUS)
Authors: Vervaecke Hilde , De Vries Han , Van Elsacker Linda
Published: July 2002

We investigated dyadic grooming relationships in a captive group of bonobos (Pan paniscus) and questioned what social function grooming fulfils in the 'market of services and favors'. Hereto we examined which of two theoretical models - grooming for support (Seyfarth, 1977, 1980) or grooming according to the similarity principle (de Waal & Luttrell, 1986) - best accounted for the observed grooming distribution. Similarity in traits did not correlate with increased grooming or close proximity among the individuals. Therefore, the similarity hypothesis was rejected. Seyfarth's model of rank-related grooming was largely confirmed. The animals distributed their grooming according to the rank of the receivers. We found an exchange between grooming and receipt of support. There was more grooming up than down the hierarchy. However, not all predictions about rank-related competition over grooming were confirmed. We found that dyadic grooming reciprocity indeed increased with decreasing rank distance. Yet, there was no increase of grooming within the dyad with decreasing rank distance and high ranking individuals were not competed over at the highest rates. The observed correlation between grooming and support received represents an important fit with Seyfarth's prediction, but does not allow for conclusions about underlying causal processes. Other causal explanations, besides the 'groom to receive support' hypothesis, that could explain a similar correlation are discussed.
TOLERATED CO-FEEDING IN RELATION TO DEGREE OF KINSHIP IN JAPANESE MACAQUES
Authors: Belisle Patrick , Chapais Bernard
Published: July 2002

We analyzed co-feeding in relation to degree of kinship in Japanese macaques Macaca fuscata), testing experimentally five categories of matrilineal kin dyads: mother-daughter, grandmother-granddaughter, sisters, aunt-niece and nonkin. In each test, two adult females with a clear dominance relationship had access to a box containing a limited quantity of highly prized food. The dominant female could easily prevent the subordinate from eating so that food was easily monopolizable, hence the use of the expression tolerated co-feeding. Rates of tolerated co-feeding increased steeply with degree of kinship. The aggression levels of dominant females towards subordinate females decreased with increasing degree of kinship and this effect was most apparent between mothers and daughters. The confidence level of subordinate females increased with degree of kinship and this effect became apparent above the aunt-niece kin class. Prior access to food by the subordinate female was a significant means of access to food, mostly beyond the grandmother-granddaughter kin category. The results point to a relatedness threshold for the preferential treatment of kin at r = 0.25 (grandmother-granddaughter and sister dyads), beyond which (r = 0.125: aunt-niece dyads), levels of tolerated co-feeding were comparable to those of nonkin females. The identity of this threshold with that found in previous studies on the same group for two different types of interactions suggests the existence of a generalized relatedness threshold for kin favoritism in Japanese macaques. Assuming that the costs of food defense by the dominant females were negligible and that tolerated co-feeding was altruistic, our results support the role of kin selection in the evolution of altruism in primates beyond the mother-offspring bond.
LEARNING BY INSTRUCTION OR SELECTION: IMPLICATIONS FOR PATTERNS OF GEOGRAPHIC VARIATION IN BIRD SONG
Authors: Nelson Douglas , Khanna Hitesh , Marler Peter
Published: July 2002

Experience can have both instructive and selective effects on vocal development in song birds. Learning by instruction occurs when one male imitates the song of another. Learning by selection occurs when a male chooses one or more songs to retain in his repertoire based on interaction with other individuals. These models of learning make different predictions about the degree of microgeographic variation in song present in wild populations of birds. If males are instructed by their immediate territory neighbors, then the songs of territory neighbors should be more similar than are the songs of non-neighbors. In contrast, if males select a song for retention that was learned elsewhere in the dialect, the songs of neighbors should be no more similar than are the songs of non-neighbors sampled from the same dialect. We compared the songs of males sampled in two sedentary populations and four migratory populations of four subspecies of the white-crowned sparrow, Zonotrichia leucophrys. In the two sedentary nuttalli populations, males on neighboring territories sang very similar songs, indicating that males are instructed by their territory neighbors after they disperse short distances to their breeding territories. Learning by selection during territory establishment after natal dispersal appears to predominate in the four migratory populations: the songs of territory neighbors were no more similar than were the songs of non-neighbors. We conclude that the sedentary/migratory distinction in the annual cycle determines the form of vocal learning that occurs between territory neighbors.
Nematode assemblages from the moss Hypnum cupressiforme Hedw. growing on different substrates in a balkanic durmast oak forest (Quercus dalechampii Ten.) on Mount Vitosha, Bulgaria
Authors: Penev Lyubomir , Lazarova Stela , Peneva Vlada
Published: July 2002

Species and generic composition, trophic structure and some ecological parameters of nematode assemblages from the moss, Hypnum cupressiforme Hedw., in a durmast oak (Quercus dalechampii Ten.) forest were studied on three substrates (soil, stone and tree trunks). Nematode abundance was very variable between samples and substrates. Nematode assemblages varied in species composition but were similar in generic composition, diversity and trophic group structure. Bacterial feeders were the most abundant, frequent and diverse trophic group, while the proportion of omnivorous and predatory nematodes was remarkably low, i.e., the nematode assemblages present can be characterised as of the 'detritus foodweb' type. No clear substrate-dependent patterns in the distribution of single species were found, with the exception of Chiloplectus andrassyi which was typical and abundant for mosses growing on stones.La composition spécifique et générique, la structure trophique et quelques paramètres écologiques des communautés de nématodes vivant dans la mousse Hypnum cupressiforme Hedw. poussant dans une forêt de chênes (Quercus dalechampii Ten.) ont été étudiés sur trois substrats: sol, rochers et troncs d'arbres. L'abondance des nématodes variait fortement suivant l'échantillon et le substrat. Les communautés de nématodes présentaient une composition spécifique variable, mais étaient très semblables en ce qui concerne la composition générique, la diversité et la structure des groupes trophiques. Les bactérivores représentaient le groupe trophique le plus abondant, fréquent et diversifié, tandis que la proportion des nématodes omnivores et prédateurs était remarquablement faible, c'est à-dire que les communautés de nématodes présentes peuvent être considérées du type 'réseau détritivore'. Aucun modèle net de dépendance envers le substrat n'a été observé dans la répartition des espèces à l'exception de Chiloplacus andrassyi, typique et abondant dans les mousses poussant sur les rochers.
Deutschland über alles?: The National Anthem Debate in the Federal Republic of Germany
Authors: Feinstein Margarete Myers
Published: July 2002

Languages evolve, and through the negotiations of public discourse, particular phrases acquire connotations and meanings beyond their grammatical structure. Occasionally, the meanings become contested and the resultant debate can be politically charged. The struggle to define language is fundamentally a struggle for power. This explains the current concerns of the French government to protect the French language from anglicisms. In recent years, the United States has become embroiled in debates over interpretations of the Constitution. Should our reconstruction of the eighteenth-century intent of the authors be the standard or should we reinterpret the language in the spirit of our present day context? The answer is fundamentally a political one. Perhaps nowhere has language been more highly contested than in postwar West Germany.
Metachromasy in clay dye systems: the adsorption of acridine orange by Na-beidellite
Authors: Garfinkel-Shweky D. , Yariv S.
Published: July 2002

The adsorption of the metachromic dye acridine orange (AO) by Na-beidellite was investigated by visible spectroscopy. Different types of clay-AO association were identified from the appearance and location of absorption bands α or β. The colloidal properties were determined from curves of the absorbance vs. the degree of saturation. Three regions were identified in the absorbance curve. In the first region beidellite is peptized with small amounts of AO and the dye penetrates into the interlayer space where it undergoes metachromasy due to π interactions between the aromatic entity and the oxygen plane of the clay. With larger amounts of AO (second region), the clay flocculates due to the aggregation of the dye cations in the interparticle space of the flocs. In excess AO (third region), beidellite is gradually peptized, forming small tactoids with monomeric AO in the interlayer space and at the same time adsorbing dimeric and polymeric AO cationic species at the solid-liquid interface. Compared with the other smectites, AO shows the greatest tendency to undergo metachromasy in the presence of beidellite.
I1̄ – I2/c ferroelastic phase transition in the Ca0.2Pb0.8Al2Si2O8 feldspar as a function of temperature
Authors: Benna P. , Tribaudino M. , Bruno E.
Published: July 2002

Feldspar of composition Ca0.2Pb0.8Al2Si2O8 (PbF80An20) was synthesized from melt and subsequently isothermally annealed at T = 960°C for 4 days. In situ HT X-ray powder spectra of PbF80An20 feldspar, triclinic I1̄ at room temperature, were collected in the temperature range 20–800°C, and a displacive continuous ferroelastic transition to a I2/c monoclinic phase was observed. An analysis of the symmetry-required components of the spontaneous strain tensor reveals the second order character (β = 0.46 ± 0.02) of the transition with TC = 680 ± 15°C. A linear coupling was observed between the e4 and e6 components of the spontaneous strain. The transition is analogous to those observed, with increasing temperature, along the join An–SrF and in disordered Na-rich alkali feldspars. A comparison with Ca0.2Sr0.8Al2Si2O8 feldspar (TC = 680°C, McGuinn and Redfern, 1997) shows that PbF80An20 has a higher spontaneous strain (εs = 0.028 in PbF80An20vs 0.020 in Ca0.2Sr0.8Al2Si2O8) and a higher e4 component, possibly related to the higher distortion of the non-tetrahedral polyhedron in lead feldspar.
Iron-rich and iron-poor prehnites from the Way Linggo epithermal Au-Ag deposit, southwest Sumatra, and the Heber geothermal field, California
Authors: Wheeler R. S. , Browne P. R. L. , Rodgers K. A.
Published: July 2002

Electron microprobe analyses of prehnites from the Way Linggo low-sulphidation epithermal Au-Ag deposit of southern Sumatra, show that the mole fraction of octahedral Fe3+, expressed as Fe3+/(Fe3++AlVI), ranges from 0.0 to ~0.6, the higher values being among the most iron-rich reported for prehnite in a hydrothermal environment. Prehnites from a diabase sill in the Heber geothermal field of California have mole fractions of octahedral Fe3+ ranging from 0.03 to 0.3. The Way Linggo prehnites formed below 220°C, some 20–30°C lower than those at the Heber field; the lower crystallization temperatures perhaps enhanced the opportunity for Fe3+ to substitute in octahedral sites. In both occurrences, prehnite predates late-stage calcite, consistent with the need for waters depositing prehnite to have aCO2 <0.01 moles. At higher CO2 activities the stability field of calcite would swamp the range of aCa2+/aH+ values appropriate for crystallizing prehnite. Consequently, the presence of prehnite in a hydrothermal environment primarily indicates that degassing of the hydrothermal fluid in CO2 occurred prior to deposition.
Use of organo-zeolitic fertilizer to sustain plant growth and stabilize metallurgical and mine-waste sites
Authors: Leggo P. J. , Ledésert B.
Published: July 2002

Land south of Lille, contaminated by heavy metals from local metal refining, has become the subject of intensive research. Topsoil from this area is used in the current work to investigate the growth behaviour of Spring wheat (Triticum aestivum L., cv. Paragon) when amended with organo-zeolitic fertilizer. Research has shown that soil substrates amended with ammoniated zeolitic tuff promote large populations of nitrifying bacteria which, as the result of ensuing enzyme reactions, produce available nitrogen together with H+ ions. It appears that the proton activity promotes cation mobilization allowing plant uptake to reach levels which, to a large extent, satisfy the nutritional requirements of the plant; only in the case of Zn is the level far exceeded. Very large differences in plant morphology occur when plants are grown in the amended substrates and the resulting development of large dense root systems, which have the ability to bind soil particles, are particularly important in their ability to reduce surface erosion and pollution from run-off.
The crystal structure of Na4(UO2)(CO3)3 and its relationship to schröckingerite
Authors: Li Yaping , Krivovichev S. V. , Burns P. C.
Published: July 2002

Crystals of the compound Na4(UO2)(CO3)3 have been synthesized and the structure has been solved. It is trigonal with a= 9.3417(6), c = 12.824(1) Å, V = 969.2(1) Å3, space group Pc1 and Z = 4. The structure was refined on the basis of F2 (wR2 = 4.2%) for all unique data collected using Mo-Kα X-radiation and a CCD-based detector. The final R1 was 2.0%, calculated for 534 unique observed (Fo ≥ 4σF) reflections, and the goodness-of-fit (S) was 0.91. The structure contains a uranyl tricarbonate cluster composed of a uranyl hexagonal bipyramid that shares three equatorial edges with CO3 triangles. The uranyl tricarbonate clusters are connected through NaO6 and NaO5 polyhedra, forming a heteropolyhedral framework structure. This compound may be related to a uranyl carbonate phase with the same composition which has been reported as an alteration phase on the surface of Chernobyl ‘lava’, and as a mineral in the Jachymov ore district, Czech Republic.
Magma replenishment, and the significance of poikilitic texlures, in the Lower Main Zone of the western Bushveld Complex, South Africa
Authors: Mitchell Andrew A. , Eales Hugh V. , Johan Kruger F.
Published: July 2002

Petrographic and compositional variations in the Lower Main Zone (LMZ) of the western Bushveld Complex indicate changing regimes of magma replenishment. The lowermost unit of the LMZ, designated N-I, is an enigmatic sequence of leuconoritic cumulates, characterized primarily by up-sequence increases in both orthopyroxene Mg# and whole-rock Sr isotope initial ratio. The Sr isotope profile of N-I is ascribed to injection and progressive integration of small influxes of fresh magma with high (Main Zone-type) Sr isotope initial ratios. The basal Fe-enrichment in N-I, on the other hand, is ascribed to a separate, later mechanism involving the downward migration of late-stage Fe-rich liquids. The overlying two units, N-II and G-I, delineated chiefly in terms of basal Mg-enrichment of orthopyroxene, are ascribed to injections of fresh magma into the chamber. Poikilitic orthopyroxene grains in the basal parts of both N-II and G-I suggest entrainment and partial resorption of plagioclase grains from the semi-crystalline resident material into which the fresh magma was intruded.
The kinetics of dehydration in Ca-montmorillonite: an in situ X-ray diffraction study
Authors: Bray Helen J. , Redfern Simon A. T. , Clark Simon M.
Published: July 2002

The thermal dehydration of naturally occurring Ca-montmorillonite has been studied by in situ X-ray diffraction at temperatures between 60–120°C. The time-temperature-dependence of the position of the basal (001) reflection reveals that interlayer water loss on isothermal dehydration occurs in two stages. After an initial rapid decrease in interlayer spacing (on shock heating to an isothermal soak temperature) the reaction proceeds towards equilibrium more slowly. Furthermore, the width of the (001) reflection changes with time, reflecting transformation-dependent changes in homogeneity perpendicular to (001) with a maximum in peak width at the point where the rate of the reaction appears to change. This suggests that, as the interlayer spacing collapses, a local change is induced in the structure, affecting the means of movement of the water from the interlayer.
Lueshite, pyrochlore and monazite-(Ce) from apatite-dolomite carbonatite, Lesnaya Varaka complex, Kola Peninsula, Russia
Authors: Chakhmouradian A. R. , Mitchell R. H.
Published: July 2002

Apatite-dolomite carbonatite at Lesnaya Varaka, Kola Peninsula, Russia, hosts intricate mineral intergrowths composed of lueshite in the core and pyrochlore-group minerals in the rim. Lueshite is a primary Nb-bearing phase in the carbonatite and ranges in composition from cerian lueshite to almost pure NaNbO3. For comparison, the compositional variation of lueshite from the Kovdor and Sallanlatvi carbonatites is described. At Lesnaya Varaka, lueshite is replaced by nearly stoichiometric Na-Ca pyrochlore due to late-stage re-equilibration in the carbonatite system. X-ray powder diffraction data for both minerals are presented. Barian strontiopyrochlore, occurring as replacement mantles on Na-Ca pyrochlore, contains up to 43% Sr and 8–18% Ba at the A-site, and shows a high degree of hydration and strong ionic deficiency at the A- and Y-sites. This mineral is metamict and, upon heating, recrystallises to an aeschynite-type structure. Monazite-(Ce) found as minute crystals in fractures, represents the solid solution between monazite-(Ce) CePO4, brabantite CaTh(PO4)2 and SrTh(PO4)2. Our data indicate the high capacity of the monazite structure for Th and accompanying divalent cations at low temperatures and pressures that has a direct relevance to solving the problem of long-term conservation of radioactive wastes. Monazite-(Ce) and barian strontiopyrochlore are products of low-temperature hydrothermal or secondary (hypergene) alteration of the primary mineral assemblage of the carbonatite.
Occurrence of primary almandine-spessartine-rich garnet and zinnwaldite
phenocrysts in a Neogene rhyolite on the island of Chios, Aegean Sea,
Greece
Authors: Mitropoulos P. , Katerinopoulos A. , Kokkinakis A.
Published: July 2002

Primary almandine and spessartine-rich garnet and zinnwaldite phenocrysts
occur along with feldspar (plagioclase and sanidine) phenocrysts, in the rhyolite
of Profitis Ilias, which is located on the SE coast of the island of Chios,
Greece. The distinctive mineralogical composition of this rhyolite is described.
Although formed in the back-arc tectonic environment of the Aegean volcanic arc,
the Profitis llias rhyolite shows significant trace element compositional
differences when compared with typical arc or back-arc volcanic rocks of the area.
It shows extreme depletion in Sr and Ba and enrichment in Nb and Mn, and has much
more affinity with A-type granites and particularly Li-mica granites.

Apparently, both zinnwaldite and spessartine-rich garnet can be generated as
primary phases from a granite melt enriched in volatile constituents at low
P–T. This granite melt
could be the residual product of an un-exposed, earlier formed, typical back-arc
granite of the area, enriched in volatile constituents from a subcrustal source
above the active mantle of the eastern Aegean area.

The extensive and deep faulting in the broad eastern Aegean lithosphere
section would have facilitated the rapid ascent of that volatile-enriched granite
melt, the parent of the Profitis Ilias rhyolite.