bluuebunny/crossref_metadata_2025 huggingface dataset:
Theopatheia: Nestorius's main charge against Cyril of Alexandria
Authors: Gavrilyuk Paul
Published: June 2003

Was Cyril of Alexandria a theopaschite? In order to resolve this controversial issue, this paper will look at Cyril's Christology with Nestorius's eyes. The charge of theopatheia appears from the very beginning in Nestorius's correspondence with Cyril and retains its central place in Nestorius's work Liber Heraclidis. The paper discusses Nestorian arguments against Cyril's position and Cyril's counter-charges. The conclusion is reached that Nestorius asserted unqualified divine impassibility. Cyril, in contrast, held a qualified view of the divine impassibility and maintained that neither divinity suffered alone, apart from humanity (in which case the assumption of humanity would be superfluous), nor humanity suffered alone, apart from and in sharp contrast to the impassible divinity (in which case the reality of divine involvement in the incarnation would be put at risk).
GIVING UP LEVELLING DOWN
Authors: BROWN CAMPBELL
Published: June 2003

The so-called “Levelling Down Objection” is commonly believed to occupy a central role in the debate between egalitarians and prioritarians. Egalitarians think that equality is good in itself, and so they are committed to finding value even in such equality as may only be achieved by “levelling down”–i.e., by merely reducing the better off to the level of the worse off. Although egalitarians might deny that levelling down could ever make for an all-things-considered improvement, they cannot deny that it may make things better in at least one respect. Prioritarians, on the other hand, do deny this; according to them, levelling down cannot make things better in any respect. In this paper I argue that the Levelling Down Objection leans far too heavily on a heretofore unanalysed notion: namely, the notion of “being better in this or that respect.” I propose what I take to be a plausible analysis of that notion, and show that, given the proposed analysis, the prioritarian is no less vulnerable to the Levelling Down Objection than is the egalitarian. I conclude that proponents of the Levelling Down Objection need either to suggest a better analysis or abandon the Levelling Down Objection altogether.
Early words, multiword utterances and maternal reading strategies as predictors of mastering word inflections in Finnish
Authors: SILVÉN MAARIT , AHTOLA ANNARILLA , NIEMI PEKKA
Published: June 2003

This is the first study to report how children's language skills and mothers' book-reading strategies, measured at 2;0, predict mastery of word inflections at 3;0 and 5;0 in a sample of 66 Finnish children. Three theoretical models were tested on the longitudinal data using path analyses. The testing of the models suggests direct developmental continuity from producing words and multiword utterances on later inflectional growth, but indirect effects of maternal strategies on language outcomes. Moreover, mothers' complex expansions and questions are positively related, whereas labellings and corrections are negatively related, to children's concurrent and subsequent language skills. Finally, vocabulary size relates negatively to maternal attention regulation. When joint attention is easily built up in the dyad, mothers concentrate more on direct reading, which, together with the child's vocabulary, predicts mastery of inflections. In conclusion, the results can be viewed as support for a child-driven view on the future course of language acquisition.
Morphosyntactic constructs in the development of spoken and written Hebrew text production
Authors: RAVID DORIT , ZILBERBUCH SHOSHANA
Published: June 2003

This study examined the distribution of two Hebrew nominal structures – N–N compounds and denominal adjectives – in spoken and written texts of two genres produced by 90 native-speaking participants in three age groups: eleven/twelve-year-olds (6th graders), sixteen/seventeen-year-olds (11th graders), and adults. The two constructions are later linguistic acquisitions, part of the profound lexical and syntactic changes that occur in language development during the school years. They are investigated in the context of learning how modality (speech vs. writing) and genre (biographical vs. expository texts) affect the production of continuous discourse.

Participants were asked to speak and write about two topics, one biographical, describing the life of a public figure or of a friend; and another, expository, discussing one of ten topics such as the cinema, cats, or higher academic studies. N–N compounding was found to be the main device of complex subcategorization in Hebrew discourse, unrelated to genre. Denominal adjectives are a secondary subcategorizing device emerging only during the late teen years, a linguistic resource untapped until very late, more restricted to specific text types than N–N compounding, and characteristic of expository writing. Written texts were found to be denser than spoken texts lexically and syntactically as measured by number of novel N–N compounds and denominal adjectives per clause, and in older age groups this difference was found to be more pronounced. The paper contributes to our understanding of how the syntax/lexicon interface changes with age, modality and genre in the context of later language acquisition.
Early syntactic creativity: a usage-based approach
Authors: LIEVEN ELENA , BEHRENS HEIKE , SPEARES JENNIFER , TOMASELLO MICHAEL
Published: June 2003

The aim of the current study was to determine the degree to which a sample of one child's creative utterances related to utterances that the child previously produced. The utterances to be accounted for were all of the intelligible, multi-word utterances produced by the child in a single hour of interaction with her mother early in her third year of life (at age 2;1.11). We used a high-density database consisting of 5 hours of recordings per week together with a maternal diary for the previous 6 weeks. Of the 295 multi-word utterances on tape, 37% were ‘novel’ in the sense that they had not been said in their entirety before. Using a morpheme-matching method, we identified the way(s) in which each novel utterance differed from its closest match in the preceding corpus. In 74% of the cases we required only one operation to match the previous utterance and the great majority of these consisted of the substitution of a word (usually a noun) into a previous utterance or schema. Almost all the other single-operation utterances involved adding a word onto the beginning or end of a previous utterance. 26% of the novel, multi-word utterances required more than one operation to match the closest previous utterance, although many of these only involved a combination of the two operations seen for the single-operation utterances. Some others were, however, more complex to match. The results suggest that the relatively high degree of creativity in early English child language could be at least partially based upon entrenched schemas and a small number of simple operations to modify them. We discuss the implications of these results for the interplay in language production between strings registered in memory and categorial knowledge.
Subject realization and crosslinguistic interference in the bilingual acquisition of Spanish and English: what is the role of the input?
Authors: PARADIS JOHANNE , NAVARRO SAMUEL
Published: June 2003

This study investigated whether crosslinguistic interference occurs in the domain of subject realization in Spanish in a bilingual acquisition context. We were also interested in exploring whether the source of the interference is due to child-internal crosslanguage contact between English and Spanish, as is commonly assumed, or due to the nature of the language input in a bilingual family, a factor which has not typically been considered in studies of crosslinguistic influence. The use of subjects in a null subject language like Spanish is a phenomenon linked to the pragmatics/syntax interface of the grammar, and thus, is a domain where crosslinguistic interference is predicted to be likely to occur in bilingual acquisition (Müller & Hulk, 2001). Using spontaneous language data available from CHILDES (www.childes.psy.cmu.edu), we examined the use of overt subjects in Spanish by two Spanish monolingual children (ages: 1;8–2;7 and 1;8–1;11) one Spanish–English bilingual child (age 1;9–2;6) and their parental interlocutors. We looked at the proportions of overt versus null subjects as well as the discourse-pragmatic contexts of overt subject use by the children in order to uncover bilingual/monolingual differences in the distributional properties and the functional determinants of subject realization. We also looked at identical variables in the speech of the children's parental interlocutors to investigate the potential influence of the input on the children's output. Our results suggest that the bilingual child showed patterns in her subject realizations in Spanish that could be interpreted as due to crosslinguistic effects from English; however, there is also evidence that these effects may have a source in the input, rather than resulting from internal crosslanguage contact. While our data do not permit us to distinguish conclusively between these two possible sources, they indicate that future research on crosslinguistic influence in bilingual acquisition should take input into account.
Opposites attract: the role of predicate dimensionality in preschool children's processing of negations
Authors: MORRIS BRADLEY J.
Published: June 2003

Three experiments investigated the role of oppositional predicate dimensionality in four- and five-year-old children's processing of negation. In Experiment 1 children (37 four-year-olds, mean age 4;8, and 20 five-year-olds, mean age 5;9) were asked to produce opposites for common terms (e.g. ‘big’). In Experiment 2 children (27 four-year-olds, mean age 4;8; 23 five-year-olds, mean age 5;9) were asked to make pictures corresponding to statements phrased as negations (e.g. The arrow is NOT pointing up). In Experiment 3, children were asked to evaluate a series of pictures made by ‘another child’ using materials and procedures similar to those used in Experiment 2. Preschool children made use of predicate dimensionality when producing negations but could accurately evaluate truth-values regardless of content. Children often recalled negated items as affirmations (usually corresponding to antipodal opposites), which suggests that children's use of predicate dimensionality contributes to non-classical processing.
Speech technologies for pronunciation feedback and evaluation
Authors: HINCKS REBECCA
Published: June 2003

Educators and researchers in the acquisition of L2 phonology have called for
empirical assessment of the progress students make after using new methods for learning
(Chun, 1998, Morley, 1991). The present study investigated whether unlimited access to a
speech-recognition-based language-learning program would improve the general standard of
pronunciation of a group of middle-aged immigrant professionals studying English in Sweden.
Eleven students were given a copy of the program Talk to Me from Auralog as a supplement to a
200-hour course in Technical English, and were encouraged to practise on their home computers.
Their development in spoken English was compared with a control group of fifteen students who
did not use the program. The program is evaluated in this paper according to Chapelle’s (2001)
six criteria for CALL assessment. Since objective human ratings of pronunciation are costly and
can be unreliable, our students were pre- and post-tested with the automatic PhonePass SET-10 test
from Ordinate Corp. Results indicate that practice with the program was beneficial to those
students who began the course with a strong foreign accent but was of limited value for
students who began the course with better pronunciation. The paper begins with an overview of the
state of the art of using speech recognition in L2 applications.
Creating a computer-based language learning environment
Authors: BARR J. DAVID , GILLESPIE JOHN H.
Published: June 2003

This paper considers key questions concerning computer-based language-learning environments.
Using evidence from current literature, it discusses the main characteristics of such environments including
human, technical and physical resources, communicative structures, information management, and cultural contexts.
It then uses data from an investigation of the universities of Cambridge, Toronto and Ulster to assess the
pedagogical effectiveness of the computer-based environments currently in operation in these three
institutions.

It considers, in particular, the integrative role that computer-based language learning environments
seem to provide. Although each institution has integrated computer technology into language teaching and learning
in different ways, a key element of each environment has been the establishment of a common computer-mediated
infrastructure, enabling effective information dissemination, resource distribution, communication and
teaching and learning. No single common infrastructure would be suitable in all three, however, in each case,
it was found that the environments created were valuable, especially in integrating elements of the teaching
and learning process that would normally have remained apart.

In concluding that the creation of a computer-based
language learning environment in the present climate is beneficial, it was noted that adequate technical
resources and a management that is keen to integrate computer technology into all aspects of university life
is a key factor in their success.
Beyond interaction: the study of collaborative activity in computer-mediated tasks
Authors: GÁNEM GUTIÉRREZ GABRIELA ADELA
Published: June 2003

Research, design, implementation, and evaluation of CALL materials needs to be based on
sound SLA theories and research. A research agenda of CALL issues needs to be identified and investigated by
means of suitable methodology. I propose that a Sociocultural approach to language learning provides a useful
theoretical framework to investigate the process of collaborative activity in computer-mediated tasks. Following
a brief overview of Sociocultural theory in relation to its claims about the usefulness of collaborative activity
in the language classroom, I provide an account of issues to be addressed in task design. Finally,
I exemplify from a study currently taking place how collaborative activity in computer-mediated tasks can
be empirically studied, and I outline some of the methodological considerations underpinning such research
work.
EUROCALL Annual Report 2001/2002
Authors: THOMPSON JUNE
Published: June 2003

EUROCALL continued to operate from the C&IT Centre of the Language
Institute at the University of Hull, with June Thompson as Secretary, Graham Chesters as
Treasurer and Julie Venner as Membership Secretary, assisted by Fred Riley and Janet Bartle.
However, due to impending changes in the staffing arrangements at Hull, steps are being taken to
identify an appropriate venue for the EUROCALL headquarters from September 2003.
La valence: l'approche pronominale et son application au lexique verbal
Authors: VAN DEN EYNDE KAREL , MERTENS PIET
Published: June 2003

L'article décrit le cadre méthodologique de l'approche pronominale et présente la base de données lexicale PROTON, un dictionnaire de valence verbale pour le français, élaboré dans cette approche. La valence y est caractérisée par les paradigmes de pronoms proportionnels (dont les traits s'unifient avec ceux des constituants comportant des éléments lexicaux). On présente, dans une forme actualisée, les notions-clef pour la description des constructions et des schèmes de valence, ainsi que les prolégomènes à la typologie des prédicateurs et de leurs actants. Ensuite on précise le contenu et les conventions formelles du lexique de valence. Une entrée du lexique est commentée à titre d'exemple. Cette même entrée est ensuite comparée aux articles correspondants du dictionnaire de valence spécialisé de Busse et Dubost (1983).
Stage-dependent sensitivity to ultraviolet radiation in zygotes of the brown alga Fucus serratus
Authors: Altamirano María , Flores-Moya Antonio , Kuhlenkamp Ralph , Figueroa Félix L.
Published: June 2003

Sensitivity to ultraviolet (UV) radiation (UV-A, λ = 315-400 nm; plus UV-B, λ = 280-315 nm) of zygotes of the brown alga Fucus serratus L. (Phaeophyta) has been assessed through effects on growth of developing germlings. Different stages of development were distinguished by considering 5 h periods of time after fertilisation. Both the stage of the zygote and the UV radiation condition significantly affected growth of developing germlings. The negative response of growth rate of early stages of the zygotes to UV radiation seemed to be caused by UV-B rather than UV-A radiation, as the lowest relative growth rates were always estimated for germlings developed from zygotes irradiated with UV-B radiation. As regards the stage of the zygote, those germlings that developed from zygotes irradiated at 5-10 h after fertilisation showed the strongest inhibition of growth compared with the other stages. These results point to polarisation as the most UV-sensitive process during the first 24 h of the development of the zygote. A non-linear relationship between the developmental stage of the zygote and the sensitivity to UV radiation is suggested.
Effect of the addition of glutathione and glucose to the culture medium on embryo development of IVM-IVF prepubertal goat oocytes
Authors: Urdaneta Aixa , Jiménez Ana Raquel , Izquierdo Dolors , Paramio María-Teresa
Published: June 2003

Our previous studies have shown that larger and more competent oocytes can be selected using the brilliant cresyl blue (BCB) test. The objective of this study was to assess, in BCB-selected oocytes, the effect on the embryo development of prepubertal goat oocytes of the addition to in vitro culture (IVC) medium of either glutathione (GSH) alone or GSH in combination with glucose . Oocytes were exposed to 26 mM BCB and were classified as: oocytes with a blue cytoplasm or grown oocytes (BCB+) and oocytes without blue cytoplasm or growing oocytes (BCB-). Oocytes were matured in TCM-199 with 100 μM cysteamine. Presumptive zygotes were cultured in synthetic oviductal fluid (SOF) in the presence or absence of 1 mM glutathione (experiment 1) for 7 days (8 days post-insemination, p.i.). In experiment 2 we tested the addition to culture of 2.78 mM glucose at day 5 p.i. BCB+ oocytes showed higher percentages of nuclear maturation than the BCB- and control groups (82.6%, 55.7% and 74.7%, respectively). The percentage of polyspermic oocytes was higher in BCB- than BCB+ oocytes. Supplementation of SOF medium with 1 mM GSH did not affect embryo development but the percentage of total embryos developed after culture was higher in BCB+ oocytes than in BCB- oocytes independently of the GSH supplementation. Glucose, alone or with GSH, added at 5 days p.i. did not affect embryo development. In conclusion, prepubertal goat oocytes were unable to develop beyond the 8-cell stage embryo under the culture conditions in this study.
Activation of pig oocytes by intracytoplasmic injection of strontium and barium
Authors: Okada Konosuke , Miyano Takashi , Miyake Masashi
Published: June 2003

Ovulated mouse oocytes are activated by exposure to culture medium containing Sr2+ or Ba2+ or by intracytoplasmic injection of the divalent cations. It is known that in vitro matured pig oocytes are activated by the intracytoplasmic injection of Ca2+. In this study, we examined the effect of exposure and of intracytoplasmic injection of Sr2+ or Ba2+ on in vitro matured pig oocytes (MII-oocytes). When MII-oocytes were exposed to the medium containing divalent cations, no oocytes were activated. However, in the case of oocytes that were injected with Sr2+, Ba2+ and Ca2+, at 6 h after injection, 64%, 71% and 86% of the oocytes had been released from MII-arrest, and 51%, 67% and 84% formed female pronuclei, respectively. The initial transient in intracellular Ca2+ concentration ([Ca2+]i)
was measured by the Ca2+ indicator dye fluo-4 dextran.
Microinjection of Sr2+, Ba2+ or Ca2+ induced a rapid
elevation of [Ca2+]i. The exocytosis of cortical
granules was examined by staining with fluorescein isothiocyanate (FITC)-labelled peanut agglutinin. After an injection of divalent cations, a release of cortical granules was observed in the oocytes. Maturation promoting factor (MPF) activity declined to a low level after 6 h in all the oocytes injected with divalent cations. To test their developmental ability, injected oocytes were treated with cytochalasin B and then cultured for 168 h in NCSU23 medium. After 168 h, 29% (Sr2+), 29% (Ba2+) and 51% (Ca2+) of the oocytes had developed to the blastocyst stage. These results indicate that intracytoplasmic injection of Sr2+ and Ba2+, like that of Ca2+, induces in vitro matured pig oocytes to be released from MII-arrest and leads them into a series of events related to oocyte activation.
Imaging intercellular calcium waves during late epiboly in intact zebrafish embryos
Authors: Webb Sarah E. , Miller Andrew L.
Published: June 2003

Through the injection of f-aequorin and the use of a photon imaging microscope, we have previously reported that a rhythmic series of intercellular Ca2+ waves circumnavigate zebrafish embryos over a 10 h period during gastrulation and axial segmentation. These waves first appear at about 65% epiboly and continue to arise every 5-10 min up to at least the 16-somite stage. In response to our publication, it was suggested that the waves may be an artefact caused by dechorionation of the embryos and would not be observed during the development of intact embryos (i.e. those with chorions). Here we demonstrate (again initially by aequorin imaging) that the rhythmic intercellular Ca2+ waves that traverse the blastoderm margin can also be observed in embryos that have an intact chorion. In addition, the appearance time, propagation pathway, velocity, duration and Ca2+ rise of the waves, as well as the interwave interval and the timing of wave onset, are approximately the same in both dechorionated embryos and those with an intact chorion. Furthermore, by loading intact embryos with Ca2+-green dextran at the single-cell stage and then using scanning confocal microscopy to obtain high-resolution images, we confirm the presence of circumferential Ca2+ waves and show that they pass through a population of deep cells located at the blastoderm margin. The confirmation of these pan-embryonic Ca2+ waves in zebrafish further corroborates our earlier suggestion that such waves might play a fundamental role in normal embryonic patterning during the gastrula period.
Changes in oligosaccharide expression on plasma membrane of the mouse oocyte during fertilisation and early cleavage
Authors: Kitamura Kimiya , Suganuma Nobuhiko , Takata Kayoko , Matsuyama Kaoru , Goto Junko , Furuhashi Madoka , Kanayama Naohiro
Published: June 2003

It has been reported that various structural and functional changes occur on the surface of the plasma membrane of the ovum and embryo during fertilisation and cleavage in preparation for implantation. Glycoproteins are thought to be one of the factors in cell attachment. Thus, we investigated the changes in glycoprotein expression on the cell surface membrane of the mouse embryo by using lectins. Among seven types of lectin (ConA, WGA, UEA-I, MPA, LCA, DBA and PNA), the fluorescent intensities of ConA and WGA markedly increased from unfertilised ova to blastocysts. By quantitative analysis using immuno-scanning electron microscopy, the numbers of ConA-gold particles were small until 4-cell cleavage, but increased significantly at the blastocyst stage. In contrast, an increased number of WGA-gold particles was detected even at the 4-cell stage, and this increase continued to the blastocyst stage. From the above observations, we conclude that the numbers of sugar chains bound to both ConA and WGA increases with blastocyst formation and earlier expression is observed with WGA. The present study clearly shows that glycoproteins on the cell membrane surface of the mouse embryo quantitatively increase at the time of implantation, and the possibility has been indicated that glycoproteins are involved in intercellular recognition and adhesion between the embryo and endometrial epithelium.
Finite state methods for hyphenation
Authors: BOUMA GOSSE
Published: June 2003

Hyphenation is the task of identifying potential hyphenation points inwords. In this paper, three finite-state hyphenation methods for Dutch are presented and compared in terms of accuracy and size of the resulting automata.
Lenient morphological analysis
Authors: OFLAZER KEMAL
Published: June 2003

This paper presents a scheme that allows one to relax the all-or-none nature of two-level constraints in two-level morphology in a controlled manner, so that word forms with violations of some of the two-level constraints can be analyzed and ranked. The problem has been motivated by a recent phenomenon in Turkish with imported words that violate a fundamental assumption of Turkish that pronunciation and orthography have almost a one-to-one correspondence, and by a problem in Basque words with differing amounts of competence errors. We present the formulation of our proposal, and provide details of implementations for both problems using the XRCE Finite State Toolkit.
Logical specification of regular relations for NLP
Authors: VAILLETTE NATHAN
Published: June 2003

This paper describes how the use of monadic second-order logic for specifying regular languages can be extended for specifying regular relations, providing a declarative description language for finite state transductions of the sort used in NLP. We discuss issues arising in the integration into an automaton toolkit of an implementation of the conversion from logic formulas to automata. The utility of the logic of regular relations is demonstrated by showing how it can be used to define the family of replacement operators in a way that lends itself to straightforward proofs of correctness.
Recursion by optimization: on the complexity of bidirectional optimality theory
Authors: JÄGER GERHARD
Published: June 2003

The paper investigates the computational complexity of different versions of Optimality Theory (OT). The result of Frank and Satta (1998) is used as a starting point. These authors show that unidirectional optimization can be implemented by finite state techniques if only binary constraints are used. The consequences of (a) taking gradient constraints into account and (b) using bidirectional optimization in the sense of Blutner (2000) are explored. The central result of the paper is that the combination of gradient constraints and bidirectionality leads to a massive increase of computational complexity.
An efficient incremental DFA minimization algorithm
Authors: WATSON BRUCE W. , DACIUK JAN
Published: June 2003

In this paper, we present a new Deterministic Finite Automata (DFA) minimization algorithm. The algorithm is incremental – it may be halted at any time, yielding a partially-minimized automaton. All of the other (known) minimization algorithms have intermediate results which are not useable for partial minimization. Since the first algorithm is easily understood but inefficient, we consider three practical and effective optimizations. The first two optimizations do not affect the asymptotic worst-case running time – though they perform well on a large class of automata. The third optimization yields an quadratic-time algorithm which is competitive with the previously known ones.
The Role of China's Bureaucracy in its No-Devaluation Policy during the Asian Financial Crisis
Authors: LIEW LEONG H.
Published: June 2003

Analysts have generally offered two explanations for China's no-devaluation policy during the Asian financial crisis. The first is China's good economic fundamentals and the renminbi is not fully convertible. The second is China's foreign relations' imperative. China was endeavouring to seek favourable entry conditions into the WTO and improve relations with its Asian neighbours. At the same time it sought to exploit the undercurrent of resentment in Asia towards the role played by the US during the crisis. Policy making in China has become more institutionalized in the post-Deng era, but these explanations ignore the role of China's domestic bureaucratic actors in exchange rate policy making. This paper examines the exchange rate regime preferences of China's key economic ministries and their influences in exchange rate policy making and argues that Party leaders were able to adopt a no-devaluation policy throughout the crisis because China's key economic ministries actively supported or acquiesced to that policy.
Does ‘Contextual Rationality’ Really Advance the Study of Rational Nomination Strategies under the Single Non-Transferable Vote?
Authors: LIU TSUNG-WEI
Published: June 2003

The concept of ‘contextual rationality’ proposed by Browne and Patterson seems to advance our understanding of rational nomination strategies under the Single Non-Transferable Vote. The plausibility of this concept hinges on the assumption of perfect information. However, perfect information not only cannot be obtained in practice, but is also impossible to obtain if we follow Browne and Patterson's approach. What their approach provides is a post hoc rationalization for parties' nomination strategies rather than a priori criterion against which whether parties make rational decisions can be judged. This approach therefore may be helpful to the study of whether parties are punished for inappropriate nomination strategies, but is far from providing the rationale for them.
Compaction localization and fluid flow
Authors: Holcomb D. J. , Olsson W. A.
Published: June 2003

When subjected to nonhydrostatic, compressive stresses, some porous sandstones exhibit nonuniform compaction. The compaction occurs as a localization process, analogous to shear localization, but results in a thickening, tabular zone of compaction as opposed to culminating in a shear fracture. We report the results of several triaxial compression experiments done at a confining pressure of 45 MPa on Castlegate sandstone, measuring simultaneously, stress, strain, acoustic emission locations, and permeability. A major result is that compaction localization produces up to a 2 order‐of‐magnitude decrease in permeability. Correlation of local strain measurements and acoustic emission locations made on the same specimen show that the compaction process proceeds as a propagating front approximately 20 mm thick. A model of the compaction process was developed that incorporates the moving boundary between compacted, low‐permeability regions and uncompacted, higher‐permeability regions, and compaction‐induced fluid injection at the boundaries. Because of the inhomogeneous nature of compaction produced by compaction localization, and its temporal evolution, a number of phenomena related to fluid flow are predicted by the model: locally increased pore pressures and spatial changes in the effective permeability. Experimental results are reported that show the evolution of effective permeability to be linear with respect to the distance the compaction fronts propagated as predicted by the model. Implications of the results for future experimentation and for reservoirs are briefly discussed; in particular, the interaction between compaction‐induced fluid pressure and compaction localization should lead to a phenomenon analogous to dilatancy hardening, impeding the propagation of compaction bands.
Warren revisited: Atmospheric freshwater fluxes and “Why is no deep water formed in the North Pacific”
Authors: Emile‐Geay Julien , Cane Mark A. , Naik Naomi , Seager Richard , Clement Amy C. , van Geen Alexander
Published: June 2003

Warren's [1983] “Why is no deep water formed in the North Pacific” is revisited. His box model of the northern North Pacific is used with updated estimates of oceanic volume transports and boundary freshwater fluxes derived from the most recent data sets, using diverse methods. Estimates of the reliability of the result and its sensitivity to error in the data are given, which show that the uncertainty is dominated by the large observational error in the freshwater fluxes, especially the precipitation rate. Consistent with Warren's conclusions, it is found that the subpolar Atlantic‐Pacific salinity contrast is primarily explained by the small circulation exchange between the subpolar and subtropical gyres, and by the local excess of precipitation over evaporation in the northern North Pacific. However, unlike Warren, we attribute the latter excess to atmospheric water vapor transports, in particular the northern moisture flux associated with the Asian Monsoon. Thus the absence of such a large transport over the subpolar North Atlantic may partly explain why it is so salty, and why deep water can form there and not in the North Pacific.
Relationship between the variation of isotopic ratios and the source of summer precipitation in eastern Siberia
Authors: Kurita Naoyuki , Numaguti Atusi , Sugimoto Atsuko , Ichiyanagi Kimpei , Yoshida Naohiro
Published: June 2003

The response of the isotopic ratio of summer precipitation in eastern Siberia to precipitation sources is estimated by examination of stable isotope ratios in the summer precipitation and by atmospheric data analysis, based on water balance considerations. The isotopic ratio (δ18O) was analyzed in samples of precipitation that were collected daily or weekly, from May 2000 to August 2000, in the Yakutsk region of eastern Siberia. The results of the isotopic data show that during spring, the variation of isotopic ratio is controlled mainly by the Rayleigh distillation process. During summer, on the other hand, the variation of isotopic ratio bears no relation to the Rayleigh process, and isotopic variation at this time is mainly caused by changes in the sources of precipitation. This is reinforced by comparison with the analysis of atmospheric data and observed isotopic data. The comparison shows that only in the summer samples, there was a good correlation (R2 = 0.88) between heavier isotopic ratios and increases in the proportion of the moisture supply that originates from the west, which is the dominant source of precipitation (about one half of the moisture). This linear relationship indicates the summer precipitation in eastern Siberia is a composite of source water from the west with heavy isotopic ratio and other sources with light isotopic ratio. The origin of this light isotopic ratio in summer precipitation might be recycled water from the land surface. Recycled water with light isotopic ratio results from the contribution of thaw water.
Pyrogenic carbon in native grassland soils along a climosequence in North America
Authors: Glaser Bruno , Amelung Wulf
Published: June 2003

Elucidating the role of pyrogenic carbon (Cpyr) as a global pool for CO2 sequestration in temperate ecosystems requires information on the contribution of Cpyr to soil organic carbon (SOC) across different climatic regions. We investigated the effect of climate and basic soil properties on the accumulation of Cpyr in surface soils across the native North American prairies. Topsoil samples (0–10 cm) of 18 native grassland sites along temperature and precipitation transects from central Saskatoon, Canada, to south Texas, USA, were analyzed for benzenecarboxylic acids as molecular markers for Cpyr after nitric acid oxidation in the bulk soil (<2 mm), clay‐ (<2 μm) and silt‐sized (2–20 μm) separates. Cpyr contributed between 4 and 18% to SOC, the major proportions of Cpyr being mostly found in the clay and silt fractions. Cpyr in soil did not correlate with basic inorganic soil properties such as pH or clay content, but it increased significantly as SOC contents increased (r2 = 0.78; P < 0.001). Obviously, Cpyr co‐accumulated with dead biomass. Since this accumulation depends on climate, also Cpyr contents in soil depend on climate and may be predicted by the logarithm of the ratio of mean annual temperature (MAT) to mean annual precipitation (MAP) (P < 0.05). We conclude that the natural potential of soils to sequester Cpyr reflects both, (1) higher Cpyr production at sites with high plant biomass in moist climates, and (2) lower Cpyr residence time at soils acting as a CO2 source in warm climates.
Percolating magmas and explosive volcanism
Authors: Gaonac'h Hélène , Lovejoy Shaun , Schertzer Daniel
Published: June 2003

Magma under pressure rises in conduits, depressurizes, forms bubbles by the exsolution of gas and – at void fractions (P) typically of the order of 0.7 – can fragment and explode. The study of overlapping geometrical units – percolation theory – predicts that at a critical volume fraction Pc the size of the largest simply connected region becomes infinite. We apply percolation theory to overlapping bubbles arguing that this geometric singularity at Pc implies a physical singularity in the magma rheology. This would imply that if the magma is under stress, ‐ whether it is ductile or brittle ‐ this rapid development of a network of infinitely long “bubbles” triggers fragmentation and explosion. Classical monodisperse (equal size) continuum percolation theory predicts Pc = 0.2985 ± 0.005 which is far from the observed values. However, it has recently been shown that the bubble distribution is a power law associated with a huge range of bubble sizes. Using Monte Carlo percolation simulations, we show that distributions exhibiting the empirical exponents are very efficient at “packing” the bubbles, drastically raising Pc to the value = 0.70 ± 0.05. Explosive volcanism is thus explained by singular rheology at Pc.
Observations of auroral broadband emissions by CLUSTER
Authors: Wahlund J.‐E. , Yilmaz A. , Backrud M. , Sundkvist D. , Vaivads A. , Winningham D. , André M. , Balogh A. , Bonnell J. , Buchert S. , Carozzi T. , Cornilleau N. , Dunlop M. , Eriksson A. I. , Fazakerley A. , Gustafsson G. , Parrot M. , Robert P. , Tjulin A.
Published: June 2003

We present the results of a study based on several events of broadband ULF/ELF emissions observed in the auroral region by the CLUSTER multi‐spacecraft at distances around 4–5 RE. These emissions, observed below the ion plasma frequency, are similar to the broadband emissions observed at lower altitudes (800–4000 km) by rockets (e.g. AMICIST) and satellites (e.g. FREJA and FAST). As successive passages of the four CLUSTER satellites through nearly the same regions show, the intensity of the emissions depend on the thermal properties of the plasma and gradients thereof. The total Poynting flux is downward and is comparable to energy fluxes observed at lower altitudes. We believe the broadband emissions are the result of dispersed Alfvén waves (DAW), which propagates down the magnetic field lines, and emits higher frequency ion plasma wave modes.
Phytoplankton bloom in the Bay of Bengal during the northeast monsoon and its intensification by cyclones
Authors: Vinayachandran P. N. , Mathew Simi
Published: June 2003

Satellite derived chlorophyll a imageries are used to present a phytoplankton bloom in the Bay of Bengal during the northeast monsoon (November–February) and the mechanisms that can upwell nutrients to sustain the bloom are investigated using sea level anomalies and winds. OCTS and SeaWiFS chlorophyll a images show that there is a phytoplankton bloom in the southwestern part of the bay during November–January. The chlorophyll a concentration of the bloom can be as high as 2 mg m−3 compared to near zero value before the bloom. Open ocean upwelling driven by Ekman pumping causes the bloom. The cyclones which are common during this period lead to localized intense blooms in the western Bay of Bengal. The offshore extent and the intensity of the bloom varies from year to year. The bloom was absent during 1997 due to weak Ekman pumping.
Coherent interannual and decadal variations in the atmosphere‐ocean system
Authors: Dickey Jean O. , Marcus Steven L. , de Viron Olivier
Published: June 2003

We investigate the source of poleward propagating atmospheric zonal wind anomalies, originating at the equator and penetrating to high latitudes in both hemispheres in conjunction with ENSO [Dickey et al., 1992], and report the discovery of similar variability on decadal and longer timescales. Since atmospheric dissipation times are generally on the order of a month or less, we examine the ocean as a “memory” source for these globally coherent anomalies. This hypothesis is substantiated by the observation of complementary oscillation in the sea surface temperature (SST) field; further, we detect a robust decadal variability (∼10–12 yrs) in both the SST and contemporaneous atmospheric angular momentum (AAM) series. Analyzing GISST SST data beginning in 1902, we confirm this decadal mode and find signatures of longer (multidecadal) SST variability centered in the equatorial and North Pacific.
Increased northeast Pacific climatic variability during the warm middle Holocene
Authors: Friddell Julie E. , Thunell Robert C. , Guilderson Thomas P. , Kashgarian Michaele
Published: June 2003

We use a pair of decadally resolved planktonic foraminiferal δ18O records from Santa Barbara Basin (SBB) to show that the warmest interval of the current interglacial, the middle Holocene, was characterized by increased decadal‐ to centennial‐scale climatic variability. Modern relationships between the Pacific Decadal Oscillation (PDO), the El Niño‐Southern Oscillation (ENSO), and upper water conditions in SBB also suggest a preference of the northeast (NE) Pacific climate during the warm mid‐Holocene toward the warm phase of the PDO and more intense ENSO warm events (“El Niños”). In the context of future climate, this study suggests increasing decadal‐ to centennial‐scale climatic variability in a globally warmed world.
Temporal variations in a four‐sheet field‐aligned current system and associated aurorae as observed during a Polar‐ground magnetic conjunction in the midmorning sector
Authors: Farrugia C. J. , Sandholt P. E. , Maynard N. C. , Torbert R. B. , Ober D. M.
Published: June 2003

We relate measurements of temporarily varying field‐aligned current systems (FACs) and their associated plasmas made by the Polar spacecraft at midmorning local times and likewise temporarily varying aurorae observed from Svalbard, Norway, when the magnetic footprint of the spacecraft passed across the field‐of‐view of the ground instruments on 3 December 1997. We combine the in situ observations of plasma and magnetic and electric fields with meridian scanning photometry and all‐sky imagery from the ground site. The interplanetary magnetic field (IMF) pointed strongly east (By ≫ 0) and generally south. Descending from ∼7.5 to ∼5.5 RE and heading south, Polar traversed a four‐sheet current system: a twin‐sheet cusp current system C1‐C2, spanning 80.6°–77.7° invariant latitudes (ILT), and then the traditional regions 1 (R1) and 2 (R2) currents, extending from 77.7° to 73.3° ILT. A convection reversal separated the C1‐C2 from the R1‐R2 FACs. Currents C1 and R2 flow out of the ionosphere, while C2 and R1 flow into the ionosphere. Within C1, Polar observed six bursts of ions of typically magnetosheath energies (≤2 keV) repeating every ∼5 min, accompanied by intensified field‐aligned electron beams and magnetic field depressions. Auroral data, acquired later but under very similar IMF conditions and at the same latitudes as when Polar was within C1, suggest auroral forms which are pulsed in both red and green lines with a similar period to the plasma bursts observed earlier at Polar. Within C2, at Polar, the pulsing ceased, but magnetosheath plasma was still present, albeit at diminished intensity. This was in part also a temporal change as the IMF clock angle decreased to ∼60°. Equatorward of the cusp aurora we find a mixing region of magnetosheath and magnetospheric plasmas with spectral characteristics of the boundary plasma sheet (BPS) forming the source of the R1 current. Plasma inhomogeneities and bipolar current elements embedded therein were related to discrete east‐west aligned arcs located equatorward of the cusp aurora. Within R2, when Polar was sampling the central plasma sheet, a field line resonance was observed on Polar and the underlying ground station HOP. A steady southward IMF rotation elicited a continued equatorward migration of all aurorae. Observations within C1‐C2 are discussed within the conceptual model of Taguchi et al. [1993] but extended to include the time‐dependent aspect so prominent in our observations. We thus hypothesize that the observations are due to time‐varying reconnection under positive By conditions. The passage of the resulting reconnected flux tubes are registered at Polar as ion bursts whose lack of significant energy‐latitude dispersion is likely due to the fact that Polar descends by only 1.1 degrees as it traverses the C1 current.
Radiation pressure measurements on micron‐size individual dust grains
Authors: Abbas M. M. , Craven P. D. , Spann J. F. , Witherow W. K. , West E. A. , Gallagher D. L. , Adrian M. L. , Fishman G. J. , Tankosic D. , LeClair A. , Sheldon R. , Thomas E.
Published: June 2003

Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2‐ to 6.82‐μm range and irradiating them from above with laser radiation focused to beam widths of ∼175–400 μm at ambient pressures ∼10−3–10−4 torr. The downward displacement of the particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least‐squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of SiO2 and the corresponding extinction and scattering efficiencies.
Quantitative relationships between plasma sheet fast flows and nightside auroral power
Authors: Shue J.‐H. , Ohtani S. , Newell P. T. , Liou K. , Meng C.‐I. , Ieda A. , Mukai T.
Published: June 2003

In this study we quantitatively investigate auroral power rate of change during periods of plasma sheet fast flows. We first identify plasma sheet fast flows from Geotail plasma and magnetic field data and then estimate the rate of change in integrated auroral power over the nightside auroral region using Polar Ultraviolet Imager auroral images over the course of the fast flows. It is found that almost all tailward fast flows are associated with increasing auroral power. Half of earthward fast flows are associated with decreasing auroral power, indicating that the earthward fast flows are not necessarily associated with increasing auroral power. In addition, we quantitatively investigate relationships between the integrated nightside auroral power rate of change and average local magnetic field Bz at Geotail during fast flow periods. We find that almost all negative Bz events are associated with increasing auroral power. The integrated auroral power for positive Bz events increases and decreases almost equally often. Results derived from a further division of the earthward fast flows events at X = −20 RE show that 67% of the earthward fast flows for X >−20 RE are associated with increasing auroral power, but 54% of the earthward fast flows for X < −20 RE are associated with decreasing auroral power. Moreover, percentage of earthward fast flows with increasing auroral power for the 2300–0100 MLT sector is significantly larger than those for other two local time sectors (2100–2300 and 0100–0300 MLT).