bluuebunny/crossref_metadata_2025 huggingface dataset:
Bilingual and monolingual processing of competing lexical items
Authors: MARIAN VIORICA , SPIVEY MICHAEL
Published: August 2003

Performance of bilingual Russian–English speakers and monolingual English speakers during auditory processing of competing lexical items was examined using eye tracking. Results revealed that both bilinguals and monolinguals experienced competition from English lexical items overlapping phonetically with an English target item (e.g., spear and speaker). However, only bilingual speakers experienced competition from Russian competitor items overlapping crosslinguistically with an English target (e.g., spear and spichki, Russian for matches). English monolinguals treated the Russian competitors as they did any other filler items. This difference in performance between bilinguals and monolinguals tested with exactly the same sets of stimuli suggests that eye movements to a crosslinguistic competitor are due to activation of the other language and to between-language competition rather than being an artifact of stimulus selection or experimental design.
Assessing phonemic awareness in kindergarten: The case for the phoneme recognition task
Authors: VAN BON W. H. J. , VAN LEEUWE J. F. J.
Published: August 2003

The validity of phoneme recognition as an indicator of phonemic awareness at kindergarten age is investigated. Six paper and pencil phonemic awareness (PA) tests, phoneme recognition among them, are administered groupwise to Dutch children a few months before the beginning of formal literacy education. Additional phonological tests and an early reading test are administered individually. Ten months later, children are tested again with PA and literacy tests. Structural equation modeling shows the relations among tests to correspond broadly with findings reported in the literature. The PA test scores are determined by one common factor, and the early PA factor influences later literacy through its influence on later PA skill. Phoneme segmentation has the highest loading on the PA factor, but phoneme recognition is its best paper and pencil representative. Unlike phoneme segmentation, phoneme recognition competence can develop in the absence of literacy skills. Phoneme recognition equals phoneme segmentation in sensitivity and specificity when predicting later literacy failure.
Nonword reading across orthographies: How flexible is the choice of reading units?
Authors: GOSWAMI USHA , ZIEGLER JOHANNES C. , DALTON LOUISE , SCHNEIDER WOLFGANG
Published: August 2003

It was predicted that children learning to read inconsistent orthographies (e.g., English) should show considerable flexibility in making use of spelling–sound correspondences at different unit sizes whereas children learning to read consistent orthographies (e.g., German) should mainly employ small-size grapheme–phoneme strategies. This hypothesis was tested in a cross-language blocking experiment using nonwords that could only be read using small-size grapheme–phoneme correspondences (small-unit nonwords) and phonologically identical nonwords that could be decoded using larger correspondences (large-unit nonwords). These small-unit and large-unit nonwords were either presented mixed together in the same lists or blocked by unit size. It was found that English children, but not German children, showed blocking effects (better performance when items were blocked by nonword type than in mixed lists). This suggests that in mixed lists, English readers have to switch back and forth between small-unit and large-unit processing, resulting in switching costs. These results are interpreted in terms of differences concerning the grain size of the phonological recoding mechanisms developed by English and German children.
A silent Finn, a silent Finno–Ugric, or a silent Nordic? A comparative study of Estonian, Finnish, and Swedish mother–adolescent interactions
Authors: TULVISTE TIIA , MIZERA LUULE , DE GEER BOEL , TRYGGVASON MARJA-TERTTU
Published: August 2003

The aim of this study was to compare some verbal characteristics of family interaction in the stereotypically tongue-tied Nordic region of the Western world. To this end we compared mothers' and early adolescents' talkativeness and monologuing and mothers' conversational dominance emerging in real-life video recordings in Estonian, Finnish, and Swedish mono- and bilingual families. All these nations have been characterized by previous research as “silent” and less talkative than other nations. The present study found that the Swedish mothers living in Sweden were talkative, as were the adolescents from Swedish monolingual and Swedish–Estonian bilingual families. In all measures of the amount of speech the mothers and adolescents from monolingual Estonian and Finnish families did not differ. According to our results, little talk seems to be characteristic of Finno–Ugric people, and the rate may be decreasing over time under the influence of a more talk-oriented cultural context.
Understanding child bilingual acquisition using parent and teacher reports
Authors: GUTIÉRREZ–CLELLEN VERA F. , KREITER JACQUELINE
Published: August 2003

There is limited research regarding what levels of proficiency in each language should characterize the language behavior of bilingual children and the impact of language exposure or language use variables on bilingual performance. This study was designed to examine the extent to which years of exposure to a language(s), amount of language input at home and at school, and amount of exposure to reading and other literacy activities in a language(s) relate to observed bilingual performance in young children, as obtained from parent and teacher reports. A secondary goal was to determine the extent to which parents or teachers could assist in determining language status by examining relationships between their ratings of the child's use and proficiency in the two languages and the child's grammatical performance. Fifty-seven children and their families were sampled from second grade classes of a large school district serving primarily low-income families in southern California. Multiple regression analyses for each language indicated that amount of Spanish input at home was a significant predictor of grammatical performance in that language. These input effects did not hold for English. Although there were some crosslinguistic differences, parent and teacher ratings of use and proficiency correlated with the child's grammatical performance in the target language. The findings suggest that parent and teacher estimates may be useful to determine bilingual status.
English word recognition and word integration skills of native Arabic- and Japanese-speaking learners of English as a second language
Authors: FENDER MICHAEL
Published: August 2003

This study investigated the effects of first language word-level reading skills on the development of English as a second language (ESL) word-level reading skills. A crosslinguistic analysis indicates that native Arabic and Japanese speakers are likely to encounter different types of ESL word-level reading difficulties. Specifically, native Arab speakers are likely to exhibit difficulties with prelexical ESL word recognition processes, whereas native Japanese speakers are likely to exhibit difficulties with on-line ESL word integration processes that integrate words into phrase/clause structures for comprehension. Results from a lexical decision task showed that a group of Japanese ESL learners had significantly faster and more accurate word recognition skills compared to a proficiency-matched Arab ESL group. In contrast, both groups read words within sentences in a sentence reading task at the same speed, though the Arab ESL group was significantly more accurate in integrating words into larger phrase and clause units and comprehending them than the Japanese ESL group. These results indicate that Arab and Japanese ESL students have different word-level reading difficulties, implicating different learning needs and pedagogical interventions for developing ESL reading proficiency.
Patterns of change in maternal–child discourse behaviors across repeated storybook readings
Authors: MCDONNELL SUSAN A. , FRIEL–PATTI SANDY , ROLLINS PAMELA ROSENTHAL
Published: August 2003

Fourteen mother–child dyads were videotaped four times over 16 days as they repeatedly read an initially unfamiliar storybook. Videotapes were transcribed and a variety of discourse measures were coded for both mother and child. Principal components analysis was used to combine three maternal and three child variables into a single composite variable, engagement, which described levels and quality of maternal and child participation in extratextual interactions during the first reading session. Dyads with the highest levels of engagement during the first session showed the greatest rates of change for a number of discourse measures. Results are discussed in terms of maternal scaffolding approaches, child participation, the importance of context and the nature of the task, and implications for intervention.
Argument structure distribution of predicates in Korean agrammatic speech
Authors: KIM YOUNG-JOO , KIM HYANGHEE , SONG HONG-KI
Published: August 2003

The present study focuses on the production of predicates by Korean agrammatic aphasic patients with respect to the argument structure distribution of the predicates. We analyzed narrative production data and picture/scene description data elicited from three Broca's aphasic patients in comparison with matched controls. In particular, we examined whether our subjects have the same kind of difficulties that Kegl's English agrammatic patient exhibited in the production of noncopular unaccusative constructions. The results show that our Korean aphasics do not exhibit any dramatic discrepancy from the control group in the pattern of argument structure distribution of the predicates produced. Regarding methodology, our studies reveal that the picture/scene description measures the subjects' competence more effectively than the narrative production task. We propose that the difference found between our agrammatic patients and Kegl's agrammatic subject may be due to the differences in the syntactic processes for deriving unaccusative constructions in the two languages.
Mode of acquisition of word meanings: The viability of a theoretical construct
Authors: WAUTERS LOES N. , TELLINGS AGNES E. J. M. , VAN BON WIM H. J. , VAN HAAFTEN A. WOUTER
Published: August 2003

This article examines the reliability and validity of the construct, mode of acquisition (MOA). The MOA of a word denotes the way in which the word's meaning is learned. A word's meaning can be acquired perceptually, linguistically, or by some combination of both. In Experiment 1, 26 student volunteers from third year special education courses rated 566 words, taken from reading texts in elementary school, on MOA. Our findings show that MOA ratings gradually change over grades, shifting from mainly perceptually acquired word meanings in Grade 1 texts to mainly linguistically acquired concepts in Grade 6 texts. In Experiment 2, 34 educational professionals completed a list on MOA, concreteness, or imageability. Judgments on the MOA proved to be different from judgments of concreteness and imageability. We suggest that the increasingly linguistic character of word meanings contribute to explaining some of the reading difficulties of deaf children.
Specific relations between alphanumeric-naming speed and reading speeds of monosyllabic and multisyllabic words
Authors: VAN DEN BOS KEES P. , ZIJLSTRA BONNE J. H. , VAN DEN BROECK WIM
Published: August 2003

The goals of this study are to investigate, at three elementary school grade levels, how word reading speed is related to rapidly naming series of numbers, letters, colors, and pictures, and to general processing speed (measured by nonnaming or visual matching tasks), and also to determine how these relationships vary with the reading task employed. The results indicate that, compared to color- and picture-naming speeds and nonnaming or visual matching speed, letter- and number-naming speeds are superior predictors of word reading speed. Furthermore, throughout the grade levels, associations between alphanumeric naming and monosyllabic word reading speeds are considerably stronger than for a widely used Dutch single-word reading test combining monosyllabic and multisyllabic words. It is suggested that, unlike multisyllabic words but similar to letters and numbers, monosyllabic words act as relatively holistic stimuli, which are recognized as sight words.
Linguistic distance and initial reading acquisition: The case of Arabic diglossia
Authors: SAIEGH–HADDAD ELINOR
Published: August 2003

The study examined phonemic awareness and pseudoword decoding in kindergarten and first grade Arabic native children. Because native speakers of Arabic first learn to read in Modern Standard Arabic (MSA), a language structurally distinct from the local form of the language they grow up speaking, it was hypothesized that the linguistic differences between the two varieties, the so-called diglossic variables, would interfere with the acquisition of basic reading processes in MSA. Two diglossic variables were examined: phoneme and word syllabic structure. The children's phoneme isolation and pseudoword decoding skills were tested. The results showed that both diglossic variables interfered with the children's performance of both tasks in both grades. The findings support the role of linguistic distance in the acquisition of basic reading processes in a diglossic context.
The processing of ambiguous sentences by first and second language learners of English
Authors: FELSER CLAUDIA , ROBERTS LEAH , MARINIS THEODORE , GROSS REBECCA
Published: August 2003

This study investigates the way adult second language (L2) learners of English resolve relative clause attachment ambiguities in sentences such as The dean liked the secretary of the professor who was reading a letter. Two groups of advanced L2 learners of English with Greek or German as their first language participated in a set of off-line and on-line tasks. The results indicate that the L2 learners do not process ambiguous sentences of this type in the same way as adult native speakers of English do. Although the learners' disambiguation preferences were influenced by lexical–semantic properties of the preposition linking the two potential antecedent noun phrases (of vs. with), there was no evidence that they applied any phrase structure–based ambiguity resolution strategies of the kind that have been claimed to influence sentence processing in monolingual adults. The L2 learners' performance also differs markedly from the results obtained from 6- to 7-year-old monolingual English children in a parallel auditory study, in that the children's attachment preferences were not affected by the type of preposition at all. We argue that children, monolingual adults, and adult L2 learners differ in the extent to which they are guided by phrase structure and lexical–semantic information during sentence processing.
Teaching English as an international language. Sandra Lee McKay. Oxford: Oxford University Press, 2002. Pp. 150.
Authors: Hamayan Else
Published: August 2003

This concise overview of English as an international language is written so clearly that not only does it provide an excellent discussion of the major issues in the field, but it also is a highly enjoyable book to read. The central premise in this book is that English is in fact an international language par excellence, and that teaching it as such and doing research in it calls for unique approaches and methodologies.
Flexibility principles in Boolean semantics: The interpretation of coordination, plurality, and scope in natural language. Yoad Winter. Cambridge, MA: MIT Press, 2001. Pp. 307.
Authors: Lasersohn Peter
Published: August 2003

Recent years have seen a whole series of book-length studies on the formal semantics of plurality and its relation to coordination, quantifier scope, and related phenomena (Landman, 2000; Lasersohn, 1995; Schein, 1993; Schwarzschild, 1996; etc.). Winter's book provides a very interesting and worthwhile addition to this list, and shows that despite the extensive attention this subject has received, there is a good deal more to be said.
Communication counts: Speech and language difficulties in the early years. Fleur Griffiths. London: David Fulton Publishers, 2002.
Authors: Nathan Liz
Published: August 2003

This book presents a personal view of working with young children who have communication problems. It is aimed at practitioners working in early years settings, including nursery teachers, teaching assistants, speech and language therapists, and parents. Fleur Griffiths communicates her practice with heartfelt conviction. The reader is left with some vivid pictures of how successful interactions can be achieved between children with communication difficulties and adults. She also describes some useful techniques for working with children. Because the book is aimed primarily at practitioners, the author might assume that her readers have knowledge of communication problems. However, the range of speech and language difficulties, the plethora of names and labels for these difficulties, the lack of precision in the use of the labels, and the differing and often competing theories of language development and disorder make it almost obligatory for an author to specify what is meant by children with communication problems and to define what is meant by any technical term or piece of professional jargon the author might use. These terms are generally not clearly defined (e.g., the age range that corresponds to “early years” is not specified). For a lay reader, this lack of context and explanation could make parts of this book difficult to follow, with terms like semantic-pragmatics and phrases like “moments of agency with a synchronous partner” (p. 23) left poorly defined.
Research into the advanced experimental methods for precision
ion stopping range measurements in matter
Authors: BAKHMETJEV I.E. , FERTMAN A.D. , GOLUBEV A.A. , KANTSYREV A.V. , LUCKJASHIN V.E. , SHARKOV B.Yu. , TURTIKOV V.I. , KUNIN A.V. , VATULIN V.V. , ZHIDKOV N.V. , BALDINA E.G. , NEUNER U. , WIESER J. , JACOBY J. , HOFFMANN D.H.H.
Published: August 2003

The article presents the results of the experimental research
on precision measurement of total stopping range and energy
deposition function of intermediate and heavy ion beams in cold
solid matter. The “thick target” method proves to
be appropriate for this purpose. Two types of detectors were
developed which provide an error of the total stopping range
measurement of less than 3% and of the beam energy deposition
function of about 7%. The experiments with 58Ni+26,
197Au+65, and 238U+72 ion
beams in the energy range 100–300 MeV/u were performed on
SIS-18 (Gesellschaft für Schwerionenforschung, Darmstadt)
in 1999–2001. The measured data on the total stopping
ranges for the above ion species in bulk and foiled Al and Cu
targets are presented. The investigation showed that there is
a noticeable discrepancy between the measured stopping ranges
and the theoretically predicted ones. Also, it was shown that
realistic ion energy deposition depends on the type of target
(bulk or foiled). Further investigation is necessary to clarify
the latter.
Stopping power of dense helium plasma for fast heavy ions
Authors: HASEGAWA J. , YOKOYA N. , KOBAYASHI Y. , YOSHIDA M. , KOJIMA M. , SASAKI T. , FUKUDA H. , OGAWA M. , OGURI Y. , MURAKAMI T.
Published: August 2003

The interaction process between fast heavy ions and dense plasma
was experimentally investigated. We injected 4.3-MeV/u or
6.0-MeV/u iron ions into a z-pinch-discharge helium
plasma and measured the energy loss of the ions by the time
of flight method. The energy loss of 4.3-MeV/u ions fairly
agreed with theoretical prediction when the electron density
of the target was on the order of 1018 cm−3.
With increasing electron density beyond 1019
cm−3, the difference between the experiment
and the theory became remarkable; the experimental energy loss
was 15% larger than the theoretical value at the peak density.
For 6.0-MeV/u ions, the deviation from the theory appeared
even at densities below 1019 cm−3.
These discrepancies indicated that density effects such as ladderlike
ionization caused the enhancement of the projectile mean charge in the
target.
Diagnostics of discharge channels for neutralized chamber
transport in heavy ion fusion
Authors: NIEMANN C. , PENACHE D. , TAUSCHWITZ A. , ROSMEJ F.B. , NEFF S. , BIRKNER R. , CONSTANTIN C. , KNOBLOCH R. , PRESURA R. , YU S.S. , SHARP W.M. , PONCE D.M. , HOFFMANN D.H.H.
Published: August 2003

The final beam transport in the reactor chamber for heavy ion
fusion in preformed plasma channels offers many attractive
advantages compared to other transport modes. In the past few
years, experiments at the Gesellschaft für
Schwerionenforschung (GSI) accelerator facility have addressed
the creation and investigation of discharge plasmas, designed
for the transport of intense ion beams. Stable, self-standing
channels of 50 cm length with currents up to 55 kA were initiated
in low-pressure ammonia gas by a CO2-laser pulse
along the channel axis before the discharge is triggered. The
channels were characterized by several plasma diagnostics including
interferometry and spectroscopy. We also present first experiments
on laser-guided intersecting discharges.
Heavy ion beam final transport through an insulator guide
in heavy ion fusion
Authors: KAWATA SHIGEO , SOMEYA TETSUO , NAKAMURA TAKASHI , MIYAZAKI SHUJI , SHIMIZU KOJI , OGOYSKI ALEKSANDAR I.
Published: August 2003

Key issues of heavy ion beam (HIB) inertial confinement fusion
(ICF) include an efficient stable beam transport, beam focusing,
uniform fuel pellet implosion, and so on. To realize a HIB fine
focus on a fuel pellet, space-charge neutralization of incident
focusing HIB is required at the HIB final transport just after
a final focusing element in an HIB accelerator. In this article,
an insulator annular tube guide is proposed at the final transport
part, through which a HIB is transported. The physical mechanism
of HIB charge neutralization based on an insulator annular guide
is as follows: A local electric field created by HIB induces
local discharges, and plasma is produced on the insulator inner
surface. Then electrons are extracted from the plasma by the
HIB net space charge. The electrons emitted neutralize the HIB
space charge well.
ECR plasma source for heavy ion beam charge neutralization
Authors: EFTHIMION PHILIP C. , GILSON ERIK , GRISHAM LARRY , KOLCHIN PAVEL , DAVIDSON RONALD C. , YU SIMON , LOGAN B. GRANT
Published: August 2003

Highly ionized plasmas are being considered as a medium for
charge neutralizing heavy ion beams in order to focus beyond
the space-charge limit. Calculations suggest that plasma at
a density of 1–100 times the ion beam density and at a
length ∼0.1–2 m would be suitable for achieving a
high level of charge neutralization. An Electron Cyclotron
Resonance (ECR) source has been built at the Princeton Plasma
Physics Laboratory (PPPL) to support a joint Neutralized Transport
Experiment (NTX) at the Lawrence Berkeley National Laboratory
(LBNL) to study ion beam neutralization with plasma. The ECR
source operates at 13.6 MHz and with solenoid magnetic fields
of 1–10 gauss. The goal is to operate the source at pressures
∼10−6 Torr at full ionization. The initial
operation of the source has been at pressures of
10−4–10−1 Torr. Electron
densities in the range of 108 to 1011
cm−3 have been achieved. Low-pressure operation
is important to reduce ion beam ionization. A cusp magnetic
field has been installed to improve radial confinement and reduce
the field strength on the beam axis. In addition, axial confinement
is believed to be important to achieve lower-pressure operation.
To further improve breakdown at low pressure, a weak electron
source will be placed near the end of the ECR source. This article
also describes the wave damping mechanisms. At moderate pressures
(> 1 mTorr), the wave damping is collisional, and at low
pressures (< 1 mTorr) there is a distinct electron cyclotron
resonance.
Conducting versus insulating walls in a heavy ion reaction chamber
Authors: VAY J.-L. , KAWATA S. , NAKAMURA T. , SASAKI J. , SOMEYA T. , DEUTSCH C.
Published: August 2003

We first pay attention to the inflight charge state distribution
in a Pb ion beam propagating in a reactor-sized chamber delimited
by metallic walls. We thus compare Livermore (code BIC) and
Orsay (code BPIC) distributions in the presence of a residual
Flibe gas pressure. Next, we replace the electron plasma due
to Flibe ionization by a gliding plasma produced by the polarization
of the incoming ion beam on insulating walls. Corresponding electrons,
when attracted by the beam, are demonstrated to yield a very efficient
current neutralization.
Effect of induced betatron motion on longitudinal wiggler
free-electron laser gain
Authors: COUHAN SHAILENDRA , MISHRA G.
Published: August 2003

In this article, we discuss the modifications that occur in
the brightness and gain of a longitudinal wiggler-free electron
laser with the aid of induced betatron oscillation. Two novel
approaches have been discussed to improve the gain of the system.
In the first scheme, an auxiliary undulator field with betatron
oscillations brings in additional bunching and results in enhanced
gain. In the second scheme, an axial magnetic field is tuned
to provide additional bunching for gain enhancement.
High-intensity ultrashort laser-induced ablation of stainless
steel foil targets in the presence of ambient gas
Authors: DI BERNARDO A. , COURTOIS C. , CROS B. , MATTHIEUSSENT G. , BATANI D. , DESAI T. , STRATI F. , LUCCHINI G.
Published: August 2003

Ablation depths of stainless steel targets irradiated by 80-fs
laser pulses at a flux F ≤ 40 J/cm2
(intensity ≤ 5 × 1014 W/cm2)
in the presence of air at atmospheric pressure are experimentally
measured. These values are lower than the theoretical predictions
for metal targets in vacuum. Results are analyzed on the basis of
the role of the ambient gas and of crater formation on the behavior
of the ablated material.
Study of optical emission from laser-produced plasma expanding
across an external magnetic field
Authors: RAI VIRENDRA N. , SINGH JAGDISH P. , YUEH FANG Y. , COOK ROBERT L.
Published: August 2003

The laser-induced plasma obtained from the liquid target and
expanding across a steady magnetic field has been studied using
atomic emission spectroscopy. The line emission from the plasma
was enhanced (>1.5 times) in the presence of a magnetic field,
whereas background emission decreases. Enhancement in line
intensity was found to be mainly a function of plasma beta (β).
An increased rate of three-body recombination in plasma particles
due to the cooling of the plasma during its expansion and an
increase in effective plasma density as a result of its confinement
seems to be the reason behind this enhancement.
X-ray spectra of fast ions generated from clusters by ultrashort
laser pulses
Authors: MAGUNOV A.I. , FAENOV A.YA. , SKOBELEV I.YU. , PIKUZ T.A. , DOBOSZ S. , SCHMIDT M. , PERDRIX M. , MEYNADIER P. , GOBERT O. , NORMAND D. , STENZ C. , BAGNOUD V. , BLASCO F. , ROCHE J.R. , SALIN F. , SHARKOV B.YU.
Published: August 2003

The high precision X-ray spectroscopy studies of plasma created
from the CO2 clusters in gas jet targets by the
ultrashort laser pulses (35 and 60 fs duration) were performed
at the intensities IL ∼
1017–1018 W cm−2. The
spectral line shape of the H-like and He-like oxygen ions gains
an asymmetry with increasing the laser pulse intensity. Theoretical
modeling of the line shape shows that the asymmetry can be
explained by absorption of the Doppler-shifted line radiation
from the essential fraction of ions (over 10−3)
with energies above 1 MeV due to photoionization of inner shells
of carbon ions. The results obtained demonstrate measurement
capabilities of the X-ray spectral measurements of multicharged
ions accelerated during the interaction with a laser radiation.
Deuterium targets and the MDMT code
Authors: AKSENOV A.G. , CHURAZOV M.D.
Published: August 2003

By means of a new two-dimensional three-temperature hydrodynamical
code we considered the burning of the deuterium fuel with a small amount
of a catalytic 3He in a cylindrical channel. To reduce the
requirements for an ignition heavy ion beam we used an irradiated DT
tablet (Jbeam = 4·106 TW/g,
Ebeam = 0.5 MJ). We received the steady burning
wave for the parameter ρr [gsim ] 8–10
g/cm2 with a gain coefficient G [gsim ] 30
in comparison with such parameters for the DT fuel G ∼
140 at ρr = 0.5 g/cm2. Upon reducing the
parameter ρr ∼ 4 g/cm2, the burning
wave disappears moving along a channel. A part of the deuterium
fuel burns with a reduced gain coefficient of 3–5. In
the case of large fuel densities ρ = 100 g/cm3,
our estimates show extremely large requirements for a compression beam
450–750 MJ for ρr ∼ 4 g/cm2.
Inverse mean free path of swift electrons in metals irradiated
by a strong laser field
Authors: MORENO-MARÍN JUAN CARLOS , ABRIL ISABEL , GARCIA-MOLINA RAFAEL , ARISTA NÉSTOR R.
Published: August 2003

We analyze the influence of a high-intensity laser field in
the inverse mean free path of electrons moving through a degenerate
electron gas. Our calculations are based on the
random-phase-approximation formalism, in terms of the dielectric
function of the medium, where the effects of the laser field
are included in the dynamical response. The main effects on
the slowing down of the electrons are studied as a function
of the intensity and frequency of the laser field, as well as
a function of the projectile velocity. A modification of the
electron inverse mean free path for plasmon and electron-hole
excitations is obtained due to multiphoton-exchange processes.
Kinetic simulation of the coherent radio emission from pulsars
Authors: SCHOPPER RÜDIGER , RUHL HARTMUT , KUNZL THOMAS A. , LESCH HARALD
Published: August 2003

On hand of 3D PIC simulations we show that in a strongly
magnetized plasma a relativistic electron beam can be forced
to emit highly coherent radio emission by self-induced nonlinear
density fluctuations. Such slowly moving nonlinear structures
oscillate with the local plasma frequency at which the relativistic
electrons are scattered. Beam electrons dissipate a significant
amount of their kinetic energy by inverse Compton radiation
at a frequency of about γ2ωpe. Since
the beam is sliced into pancake structures which experience
the same electric field the inverse Compton scattering is coherent.
Such a process is a very promising candidate for the coherent
radio emission of pulsars.
High-power UV excilamps excited by a glow discharge
Authors: SKAKUN V.S. , LOMAEV M.I. , TARASENKO V.F. , SHITTS D.V. , JOHNSON G.L. , WANG F.T.
Published: August 2003

The results on study of light sources based on spontaneous
radiation of molecules KrCl* (λ ∼ 222 nm) and XeCl*
(λ ∼ 308 nm) excited by a glow discharge are presented.
It is demonstrated that additions of light inert gases (He and
Ne) lead to increase in emission of radiation power and efficiency
in mixtures Kr(Xe)-Cl2. A high-power cylindrical
multi-section excilamp was built and energy, time, and spectrum
characteristics have been studied. Average output power obtained
in the UV spectral range were 1,9 kW at λ ∼ 222 nm and
1,1 kW at λ ∼ 308 nm with efficiencies with respect
to the excitation power of up to 14%.
Conceptual, methodological, and statistical issues in developmental psychopathology: A Special Issue in honor of Paul E. Meehl
Authors: CICCHETTI DANTE , HINSHAW STEPHEN P.
Published: August 2003

With the passing of Paul E. Meehl, Regents Professor of Psychology at the University of Minnesota, on February 14, 2003, the world lost one of the most influential clinical psychologists of the 20th century. The breadth of his interests, the preciseness and clarity of his thinking, the elegance of his writing, and his ability to integrate scientific and clinical matters of import were hallmarks of his illustrious career (see, e.g., Meehl, 1954, 1973, 1991). Yet, it is the very magnitude of his professional pursuits that defy categorization or even placement within a single field of inquiry. Whether they pertain to philosophical matters, measurement and psychodiagnostic issues, or elucidating psychopathological processes, Paul Meehl's contributions were seminal and established a base on which scholars could build their own theoretical and research perspectives. Although Paul certainly did not consider himself to be a developmental psychopathologist, his influence can be seen in the theoretical and methodological streams that have nurtured the emergence and growth of the field. Thus, it seems a fitting tribute to Paul that this Special Issue, “Conceptual, Methodological, and Statistical Issues in Developmental Psychopathology,” be dedicated in his honor.
Taxometrics and developmental psychopathology
Authors: BEAUCHAINE THEODORE P.
Published: August 2003

Developmental psychopathologists have criticized categorical classification systems for their inability to account for within-group heterogeneity in biological, etiological, developmental, and cultural influences on behavior. Dichotomizing continuous scores of symptom severity is also inadvisable statistically. Perhaps because of a resulting wariness of categorizing, few explorations into the ontological status of traits or disorders as dimensional versus discrete have been conducted. It is argued here that the limitations of categorizing have little to do with the ontological status of traits and that developmental psychopathologists should be concerned with identifying discrete behavioral syndromes. Common taxometric methods for resolving discrete traits are described, and questions of concern to developmental psychopathologists are outlined that can be addressed through taxometrics studies. These include (a) identifying children who are at risk for future psychopathology, (b) identifying discrete subtypes within current diagnostic classes, (c) locating sensitive periods in the development of discrete pathological traits, (d) discovering moderators of treatment outcome, and (e) elucidating mechanisms of equifinality and multifinality. Although most behavioral traits probably are distributed continuously, identifying those that are discrete will advance the science of developmental psychopathology. Disorders for which taxometric analyses might be applied include anxiety, attention deficit hyperactivity disorder, autism spectrum disorders, conduct problems, depression, and schizophrenia.
Natural categories or fundamental dimensions: On carving nature at the joints and the rearticulation of psychopathology
Authors: PICKLES ANDREW , ANGOLD ADRIAN
Published: August 2003

The question of whether to view psychopathology as categorical or dimensional continues to provoke debate. We review the many facets of this argument. These include the pragmatics of measurement; the needs of clinical practice; our ability to distinguish categories from dimensions empirically; methods of analysis appropriate to each and how they relate; and the potential theoretical biases associated with each approach. We conclude that much of the debate is misconceived in that we do not observe pathology directly; rather, we observe its properties. The same pathology can have some properties that are most easily understood using a dimensional conceptualization while at the same time having other properties that are best understood categorically. We suggest replacing Meehl's analogy involving qualitatively distinct species with an alternative analogy with the “duality” of light, a phenomenon with both wave- and particle-like properties.
Research strategies in developmental psychopathology: Dimensional identity and the person-oriented approach
Authors: VON EYE ALEXANDER , BERGMAN LARS R.
Published: August 2003

This article deals with alternative research strategies for developmental psychopathology. It argues that most applications of statistical methods in empirical research are variable centered, not person oriented. As a result, conclusions are often drawn that fail to do justice to the diverse nature of populations. It is recommended that we take seriously the importance of the implications of data aggregation. The difficulties of making inferences from a more aggregated level of analysis to a less aggregated level are explained and exemplified. We explain that a set of variables displays dimensional identity if the variable relationships remain unchanged across the levels or categories of other variables. Data examples of intelligence divergence and of Child Behavior Checklist subpopulation differences show that lack of dimensional identity can lead to incorrect conclusions. Schmitz' theorems on aggregation and the validity of results at the aggregate level for individuals are illustrated using data from a study on the development of alcoholism and discussed from a person-oriented perspective. Statistical methods suitable for person-oriented data analysis are reviewed.
Implications of latent trajectory models for the study of developmental psychopathology
Authors: CURRAN PATRICK J. , WILLOUGHBY MICHAEL T.
Published: August 2003

The field of developmental psychopathology is faced with a dual challenge. On the one hand, we must build interdisciplinary theoretical models that adequately reflect the complexity of normal and abnormal human development over time. On the other hand, to remain a viable empirical science, we must rigorously evaluate these theories using statistical methods that fully capture this complexity. The degree to which our statistical models fail to correspond to our theoretical models undermines our ability to validly test developmental theory. The broad class of random coefficient trajectory (or growth curve) models allow us to test our theories in ways not previously possible. Despite these advantages, there remain certain limits with regard to the types of questions these models can currently evaluate. We explore these issues through the pursuit of three goals. First, we provide an overview of a variety of trajectory models that can be used for rigorously testing many hypotheses in developmental psychopathology. Second, we highlight what types of research questions are well tested using these methods and what types of questions currently are not. Third, we describe areas for future statistical development and encourage the ongoing interchange between developmental theory and quantitative methodology.
Research strategies for capturing transactional models of development: The limits of the possible
Authors: SAMEROFF ARNOLD J. , MACKENZIE MICHAEL J.
Published: August 2003

Transactional models have informed research design and interpretation in studies relevant to developmental psychopathology. Bidirectional effects between individuals and social contexts have been found in many behavioral and cognitive domains. This review will highlight representative studies where the transactional model has been explicitly or implicitly tested. These studies include experimental, quasiexperimental, and naturalistic designs. Extensions of the transactional model have been made to interventions designed to target different aspects of a bidirectional system in efforts to improve developmental outcomes. Problems remain in the need to theoretically specify structural models and to combine analyses of transactions in the parent–child relationship with transactions in the broader social contexts. Longitudinal studies with sufficient time points to assess reciprocal processes continue to be important. Such longitudinal investigations will permit identifying developmental periods where the child or the context may be most influential or most open to change.
Dynamic systems methods for models of developmental psychopathology
Authors: GRANIC ISABELA , HOLLENSTEIN TOM
Published: August 2003

A survey of dynamic systems (DS) methods appropriate for testing systems-based models in developmental psychopathology is provided. The rationale for developing new methods for the field is reviewed first. In line with other scholars, we highlight the fundamental incompatibility between developmentalists' organismic, open systems models and the mechanistic research methods with which these models are tested. Key DS principles are explained and their commensurability with developmental psychopathologists' core theoretical concerns are discussed. Next, a survey of research designs and methodological techniques currently being used and refined by developmental DS researchers is provided. The strengths and limitations of each approach are discussed throughout this review. Finally, we elaborate on one specific dynamic systems method, state space grids, which addresses many of the limitations of previous DS techniques and may prove most useful for the discipline. This approach was developed as a middle road between DS methods that are mathematically heavy on the one hand and purely descriptive on the other. Examples of developmental and clinical studies that have applied state space grids are reviewed and suggestions for future analyses are made. We conclude with some implications for the application of this new methodology for studying change processes in clinical research.
Early experiences and psychological development: Conceptual questions, empirical illustrations, and implications for intervention
Authors: O'CONNOR THOMAS G.
Published: August 2003

This paper reviews alternative conceptual and descriptive models of how early exposure to risk may predict later development. Particular attention is paid to the methodological and data analytic strategies for differentiating among the models. Example empirical illustrations of human studies are then provided that highlight the potential significance of early experiences for behavioral/emotional development. Finally, implications of these models of early experiences for intervention and prevention are examined and identified as an important methodological tool for further research.
The development of psychopathology in females and males: Current progress and future challenges
Authors: CRICK NICKI R. , ZAHN–WAXLER CAROLYN
Published: August 2003

In recent years, the role of gender in the development of psychopathology has increasingly attracted the attention of researchers, theoreticians, and other professionals interested in the well-being of children and adolescents. This interest has taken diverse forms, ranging from the examination of sex differences in the prevalence of adjustment difficulties to the exploration of unique etiologies and trajectories in the development of psychopathology for boys versus girls. In this paper we (a) critically examine the current status of available theories, research, and methods related to the study of gender and psychopathology and provide recommendations for future work; (b) identify promising new trends that appear to have utility for enhancing our understanding of the role of gender in the development of adjustment difficulties; and (c) generate conclusions regarding gender and psychopathology by integrating information from past and present work with new ideas about fruitful directions for future inquiry.
Moving research on resilience into the 21st century: Theoretical and methodological considerations in examining the biological contributors to resilience
Authors: CURTIS W. JOHN , CICCHETTI DANTE
Published: August 2003

Empirical investigations of resilience over the past 30 years have examined a wide range of psychosocial correlates of, and contributors to, this phenomenon. Thus far, theoretical treatments of resilience have focused almost exclusively on psychosocial levels of analysis to derive explanatory models. However, there have been no formal discussions of either theory or research that have examined the biological contributors to, or correlates of, competent functioning despite the experience of adversity. This paper seeks to fill this gap and sets forth a preliminary theoretical framework and outline of empirical strategies for studying the biological underpinnings of resilience. The initial sections of the paper discuss the particular suitability of a transactional organizational theoretical perspective as a conceptual foundation for including a biological level of analysis within the extant theoretical framework of resilience. Subsequently, other important theoretical considerations for the inclusion of a biological perspective on resilience are discussed, including the avoidance of an approach that would reduce resilience to merely a biological process, the application of the constructs of multifinality and equifinality to a biological perspective on resilience, as well as a general discussion of the potential for utilization of brain imaging and other technologies in the study of resilience. The possible relation between the mechanisms of neural plasticity and resilience are examined in some detail, with specific suggestions concerning research questions needed to examine this association. Sections of the paper discuss the likely relation of several areas of brain and biological functioning with resilience, including emotion, cognition, neuroendocrine and immune functioning, and genetics. The paper concludes with a discussion of the implications of a biological perspective on resilience for preventive interventions.
VOLUMETRIC AND STYLISTIC REASSESSMENT OF CLASSIC MAYA SITES IN THE PETEN, RÍO BEC, CHENES, AND PUUC HILLS
Authors: Adams R. E. W. , Adams Jane Jackson
Published: August 2003

This paper seeks to define and discuss the nature, size, variety, ideology, and change in the polities of three regions of the Maya Lowlands: the Greater Peten, Central Yucatan (Río Bec/Chenes), and the Puuc Hills. Patterned variety is demonstrable on all levels of analysis and even within stylistic regions, within suggested regional states, and within sites.
CLIMATE CHANGE AND DEFORESTATION: Implications for the Maya collapse
Authors: Shaw Justine M.
Published: August 2003

During the ninth century, many sites in the Southern Maya Lowlands were abandoned as elite and commoners felt the effects of the Classic-period Maya collapse. At the same time, sites to the north and east continued to flourish. Recent climatic data indicate that, at this time, much of the Maya area experienced a significant drought. However, this drought does not appear to have uniformly affected the entire region; instead, climate appears to have acted as a mosaic, shifting through time and space. It is hypothesized that one of the key factors responsible for these variable cultural trajectories is localized and regional climate change brought about through irregular anthropogenic deforestation. These changes, when coupled with an out-of-balance cultural system, may have served as a catalyst that sent some parts of the Maya world down the path to systems failure, while other zones were able—at least, temporarily—to adjust and continue.
T. PATRICK CULBERT: An appreciation
Authors: Yoffee Norman
Published: August 2003

Pat Culbert's scholarship and teaching are marked by both an
insistence on rigorous attention to data and a gentleness and
humaneness in which scholarly inquiry should flourish. I discuss in
this paper one aspect of his research—the size and degree of
political integration of Maya polities—by means of a comparison
with Mesopotamian examples.
SHAPING CERAMIC RESEARCH AT THE MAYA SITE OF CUELLO, BELIZE
Authors: Kosakowsky Laura J.
Published: August 2003

Traditional analyses of ceramics from Maya Lowland archaeological
sites have focused on descriptive typologies to define site and regional
chronologies. However, T. Patrick Culbert's groundbreaking work on
the ceramics of Tikal (1993) utilized vessel
shapes, as well, involving an analytical system of two levels: shape
classes and shapes. His systematized modal analysis and concentration
on vessel-shape classes, in conjunction with a focus on the importance
of deposit types and site-formation processes, revolutionized what
ceramics can tell us about prehistoric Maya behavior. The same approach
was applied to the research on the Cuello ceramics presented here to
gain a better understanding of the behavior associated with
ceramic-vessel usage during the Preclassic period at this northern
Belize site.