bluuebunny/crossref_metadata_2025 huggingface dataset:
METHODS FOR ASSESSING CHILDREN'S SYNTAX.Dana
McDaniel, Cecile McKee, & Helen Smith Cairns (Eds.). Cambridge, MA: MIT Press,
1996. Pp. xviii + 390. $45.00 cloth.
Authors: Lakshmanan Usha
Published: July 2002

Methods for assessing children's syntax is an invaluable contribution to the
study of child syntax. As the editors note in their preface, the volume has two major aims. First,
it is designed in part to function as a how-to manual to aid students and researchers in the
selection and use of methods for investigating children's linguistic performance and
competence. Second, it is intended to serve as a valuable resource for the evaluation of research
in the area of child language acquisition. The volume, which includes contributions by some of
the most prominent scholars in the field, succeeds admirably in fulfilling both of the above
goals.
Cr [Kscr ]-versality of the graph
deformation of a Cr stable map-germ
Authors: NISHIMURA TAKASHI
Published: July 2002

In his celebrated paper [7], Martinet
showed the equivalence between the
infinitesimal versality and the versality for [Ascr ]- and [Kscr ]-morphisms. By using this
theorem, he obtained the following Theorem 1·1 which played one of the key roles
for the classification of C∞ stable map-germs
([1, 7]).
Identification of Ships and Transfer of Information through Transponders
Authors: Poleo Mora Antonio J. , Melón Enrique García , Pérez José Díaz
Published: July 2002

In this paper, we shall outline the reasons why the installation

of shipborne equipment, which
enables vessels to be positively identified from the shore and from other

vessels, is so important
and necessary. We shall also describe the latest innovations in this field
and propose minimum
standards for a transponder system.
Satellite-Based Augmentation
Systems: The Need for International
Standards
Authors: Kinal George V. , Ryan Fintan
Published: July 2002

This paper discusses the technical, administrative and certification
compatibility issues
associated with satellite augmentation of GPS/GLONASS. It indicates
that the Signal-in-Space specifications are central to compatibility and interoperability.
ICAO Standards and
Recommended Practices are a key mechanism for interoperability. The paper
recommends
that one standard be implemented worldwide. It also urges a mechanism for
the
co-ordination and management of augmentation services.
Remembering, forgetting, and the effects of trauma on memory:
A developmental psychopathology perspective
Authors: TOTH SHEREE L. , CICCHETTI DANTE
Published: July 2002

A developmental psychopathology framework, with its emphasis on an interdisciplinary
perspective, the interplay between work conducted with normal and atypical populations, and its
focus on investigating functioning in multiple domains of development concurrently, possesses
significant potential for advancing work on memory and trauma. A brief historical overview of
memory and trauma is provided. Significant issues are highlighted that must be confronted in
order to advance the understanding of the effects of trauma on memory and the utility of a
developmental psychopathology perspective for informing research efforts is examined. The
implications of a developmental psychopathology perspective for guiding research, clinical, and
social policy initiatives of relevance to trauma and memory are discussed.
Asymptotic analysis of the bifurcation diagram
for symmetric one-dimensional solutions of the
Ginzburg–Landau equations
Authors: AFTALION A. , CHAPMAN S. J.
Published: July 2002

The bifurcation of symmetric superconducting solutions from the normal solution is
considered for the one-dimensional Ginzburg–Landau equations by the methods of formal
asymptotics. The behaviour of the bifurcating branch depends upon the parameters d, the
size of the superconducting slab, and κ, the Ginzburg–Landau parameter. It was found
numerically by Aftalion & Troy [1] that there are three distinct regions of the
(κ, d) plane, labelled S1, S2 and
S3, in which there are at most one, two and three symmetric solutions
of the Ginzburg–Landau system, respectively. The curve in the
(κ, d) plane across which the bifurcation switches from being subcritical to
supercritical is identified, which is the boundary between
S2 and S1∪S3,
and the bifurcation diagram is analysed in its vicinity. The triple point,
corresponding to the point at which S1, S2 and
S3 meet, is determined, and the bifurcation
diagram and the boundaries of S1, S2 and
S3 are analysed in its vicinity. The results provide
formal evidence for the resolution of some of the conjectures of
Aftalion & Troy [1].
On the uniqueness of solutions of the Ginzburg–Landau system for thin films
Authors: AFTALION AMANDINE , TROY WILLIAM C.
Published: July 2002

In this paper we investigate the uniqueness of solutions of the Ginzburg–Landau system for
superconductivity in the regime where the thickness 2a of the film is small. We analyse the
equations of first variation with respect to two shooting parameters and obtain estimates on
all relevant quantities at the end of the film where the boundary conditions are prescribed.
Using these estimates, we prove that the bifurcation curve of symmetric solutions is given by
a decreasing function of the order parameter β when the film is thin enough. In addition, we
prove that there is no curve of asymmetric solutions branching from the symmetric curve.
Dynamic tabbing for automatic indentation with the layout rule
Authors: LAPALME GUY
Published: July 2002

We show the design principles of an automatic indentation GNU Emacs
mode for Haskell
and Miranda(tm), functional languages using the ‘layout rule’

instead of the usual parenthetic
structures for indentifying dependent program parts.
Computer mediated communication: learning German online in Australia
Authors: MÖLLERING MARTINA
Published: July 2002

This article investigates the use of computer-mediated communication technologies in the context
of teaching German by distance mode in Australia. More conventional delivery modes such as audiocassettes
and printed study guides were augmented by electronic support mechanisms. Students were able to access their
study guides, timetables and assignment tasks online and communicated with their course convener as well
as with fellow students via a bulletin board and an internal email system set up for the course. The article
reports on the extent to which students used these facilities rather than more conventional modes of
communication (fax., telephone, written submission of assignments), on how students managed the set tasks
and what difficulties they encountered.
CQ Sources/Bibliography
Authors: Young Judith Schaeffer
Published: July 2002

These CQ Sources were compiled by Judith Schaeffer Young.
The Path Resistance Method for Bounding the
Smallest Nontrivial Eigenvalue of a Laplacian
Authors: GUATTERY S. , LEIGHTON T. , MILLER G. L.
Published: July 2002

We introduce the path resistance method for lower bounds on the smallest nontrivial
eigenvalue of the Laplacian matrix of a graph. The method is based on viewing the graph
in terms of electrical circuits: it uses clique embeddings to produce
lower bounds on λ2 and
star embeddings to produce lower bounds on the smallest Rayleigh quotient when there
is a zero Dirichlet boundary condition. The method assigns priorities to the paths in the
embedding; we show that, for an unweighted tree T, using uniform priorities for a clique
embedding produces a lower bound on λ2 that is off by at most
an O(log diameter(T)) factor. We show that the best bounds this method can
produce for clique embeddings are the same as for a related method that uses clique embeddings
and edge lengths to produce bounds.
The DINOUS parser
Authors: DRAGGIOTIS ANTHONY , GRIGORIADOU MARIA , PHILOKYPROU GIORGOS
Published: July 2002

This paper deals with the development of parsing techniques for
the analysis of natural
language sentences. We present a paradigm of a multi- path shift-reduce
parser which
combines two differently structured computational subsystems. The first
uses information
concerning native speakers' preferences, and the second
deals with the linguistic knowledge.
To apply preferences on parsing, we propose a method to rank the alternative
partial analyses
on the basis of parse context and frequency of use effects. The method
is mainly based
on psycholinguistic evidence, since we hope eventually to build a parser
working as closely
as possible to the way native speakers analyse natural sentences. We also
discuss in detail
techniques for optimizing the effectiveness of the proposed model. The
system has worked
successfully in parsing sentences in Modern Greek, a language where the
relatively free word
order characteristic results in many ambiguity problems. The proposed parsing
model is
consistent with many directions in the field of preference-based parsing,
and it is proved to
be adequate in building effective and maintainable natural language analysers.
It is believed
that this model can also be used in parsing sentences in languages other
than Greek.
At Last, Neuropsychology's Coming Of Age
Authors: Walter Marc S.
Published: July 2002

In his forward to Clinical Neuropsychology
Arthur Benton comments, “More aptly than might have
been anticipated, clinical neuropsychology is coming of
age. I mean by this that it is evolving from what was largely
a set of assessment procedures coupled with a diagnostic
inference to be drawn from them into a true discipline,
conscious of its conceptual bases and concerned with the
cognitive and neuromechanisms that mediate the behavior
of normal individuals and patients with brain disease.”
Dr. Benton's assessment catches the thrust of the
book well. It concerns itself with the development and
maturation of the field, its relationship to sister disciplines
such as behavioral neurology and neuropsychiatry, focuses
in on important practice and credentialing issues, and
provides cogent reviews of progress in many important content
areas.
Obsessed With Tics
Authors: Denckla Martha Bridge
Published: July 2002

This is an excellent clinical textbook by a group
steeped in a quarter of a century's clinical experience
and basic research experience. For members of INS who desire
a rich and deep resource book on Tourette syndrome (this
reviewer was trained to omit the possessive ‘s’
for all eponymous genetic designations) this one from the
Yale Child Study Center provides the best choice. The organization
of the book is also praiseworthy, as each chapter ends
with a “look back” summary and a preview of
the next chapter. It has the virtues of harmonious voices,
coming as it does from a single center. The medical (including
but not limited to neuropsychiatric) and biological sciences
are presented in depth, clearly and thoughtfully, and well
integrated with the clinical breadth of coverage of the
core disorder and Tourette syndrome's (TS) comorbidities.
Attention Deficit Hyperactivity Disorder (ADHD), and Obsessive
Compulsive Disorder (OCD).
Treatment of naming disorders: New issues regarding old therapies
Authors: HILLIS ARGYE E.
Published: July 2002

I report a series of single case studies involving
an aphasic patient, H.G., which illustrates both the usefulness
and the limitations of cognitive neuropsychological models
and methods in aphasia rehabilitation. The first set of
experiments analyze H.G.'s pattern of performance
across lexical tasks in order to identify the loci of her
damage to the cognitive mechanisms underlying the tasks
of naming, comprehension, repetition, reading, and spelling.
The second set of studies evaluates her response to two
different types of treatment and identifies a few of the
variables that influence the effectiveness of treatment.
(JINS, 1998, 4, 648–660.)
Legislative Records, 2000
Authors: Iwai Tomoaki
Published: July 2002

The political scene behind Japan's legislation in 2000 was uneasy and flurried. The ascent to political power by Prime Minister Yoshiro Mori following the sudden death of Prime Minister Keizo Obuchi, the shift in political framework caused by the separation of the Liberal Party from the coalition government, and the general election came one after the other in a series of restless succession.
Editor's Introduction to the inaugural issue
Authors: Blackhurst Richard
Published: July 2002

For much of the post-war period, interest in the multilateral trading system – as
embodied in the General Agreement on Tariffs and Trade (GATT) – was limited to
national delegates posted to Geneva, a small number of technocrats in capitals, and
a handful of academics, mostly legal scholars plus a few economists and an even
smaller number of political scientists. Among politicians and the general public, the
GATT was virtually unknown. During those years, a professional journal devoted
exclusively to the multilateral trading system would have been hard pressed to fill its
pages.
The chimeric leucine-rich repeat/extensin cell wall protein LRX1 is required for root hair morphogenesis inArabidopsis thaliana
Authors: Baumberger Nicolas , Ringli Christoph , Keller Beat
Published: July 2002

In plants, the cell wall is a major determinant of cell morphogenesis. Cell enlargement depends on the tightly regulated expansion of the wall, which surrounds each cell. However, the qualitative and quantitative mechanisms controlling cell wall enlargement are still poorly understood. Here, we report the molecular and functional characterization ofLRX1, a newArabidopsisgene that encodes a chimeric leucine-rich repeat/extensin protein.LRX1is expressed in root hair cells and the protein is specifically localized in the wall of the hair proper, where it becomes insolubilized during development.lrx1-null mutants, isolated by a reverse-genetic approach, develop root hairs that frequently abort, swell, or branch. Complementation and overexpression experiments using modified LRX1 proteins indicate that the interaction with the cell wall is important for LRX1 function. These results suggest that LRX1 is an extracellular component of a mechanism regulating root hair morphogenesis and elongation by controlling either polarized growth or cell wall formation and assembly.
The orphan receptor ALK7 and the Activin receptor ALK4 mediate signaling by Nodal proteins during vertebrate development
Authors: Reissmann Eva , Jörnvall Henrik , Blokzijl Andries , Andersson Olov , Chang Chenbei , Minchiotti Gabriella , Persico M. Graziella , Ibáñez Carlos F. , Brivanlou Ali H.
Published: July 2002

Nodal proteins have crucial roles in mesendoderm formation and left–right patterning during vertebrate development. The molecular mechanisms of signal transduction by Nodal and related ligands, however, are not fully understood. In this paper, we present biochemical and functional evidence that the orphan type I serine/threonine kinase receptor ALK7 acts as a receptor for mouse Nodal and Xenopus Nodal-related 1 (Xnr1). Receptor reconstitution experiments indicate that ALK7 collaborates with ActRIIB to confer responsiveness to Xnr1 and Nodal. Both receptors can independently bind Xnr1. In addition, Cripto, an extracellular protein genetically implicated in Nodal signaling, can independently interact with both Xnr1 and ALK7, and its expression greatly enhances the ability of ALK7 and ActRIIB to respond to Nodal ligands. The Activin receptor ALK4 is also able to mediate Nodal signaling but only in the presence of Cripto, with which it can also interact directly. A constitutively activated form of ALK7 mimics the mesendoderm-inducing activity of Xnr1 in Xenopus embryos, whereas a dominant-negative ALK7 specifically blocks the activities of Nodal and Xnr1 but has little effect on other related ligands. In contrast, a dominant-negative ALK4 blocks all mesoderm-inducing ligands tested, including Nodal, Xnr1, Xnr2, Xnr4, and Activin. In agreement with a role in Nodal signaling, ALK7 mRNA is localized to the ectodermal and organizer regions of Xenopus gastrula embryos and is expressed during early stages of mouse embryonic development. Therefore, our results indicate that both ALK4 and ALK7 can mediate signal transduction by Nodal proteins, although ALK7 appears to be a receptor more specifically dedicated to Nodal signaling.
The ATM-related domain of TRRAP is required for histone acetyltransferase recruitment and Myc-dependent oncogenesis
Authors: Park Jeonghyeon , Kunjibettu Sudeesha , McMahon Steven B. , Cole Michael D.
Published: July 2002

The ATM-related TRRAP protein is a component of several different histone acetyltransferase (HAT) complexes but lacks the kinase activity characteristic of other ATM family members. We identified a novel function for this evolutionarily conserved domain in its requirement for the assembly of a functional HAT complex. Ectopic expression of TRRAP protein with a mutation in the ATM-related domain inhibits Myc-mediated oncogenic transformation. The Myc-binding region of TRRAP maps to a separable domain, and ectopic expression of this domain inhibits cell growth. These findings demonstrate that the ATM-related domain of TRRAP forms a structural core for the assembly and recruitment of HAT complexes by transcriptional activators.
BIG: a calossin-like protein required for polar auxin transport in Arabidopsis
Authors: Gil Pedro , Dewey Elizabeth , Friml Jiri , Zhao Yunde , Snowden Kimberley C. , Putterill Jo , Palme Klaus , Estelle Mark , Chory Joanne
Published: July 2002

Polar auxin transport is crucial for the regulation of auxin action and required for some light-regulated responses during plant development. We have found that two mutants ofArabidopsis—doc1, which displays altered expression of light-regulated genes, and tir3, known for its reduced auxin transport—have similar defects and define mutations in a single gene that we have renamed BIG. BIG is very similar to theDrosophila gene Calossin/Pushover, a member of a gene family also present in Caenorhabditis elegans and human genomes. The protein encoded by BIG is extraordinary in size, 560 kD, and contains several putative Zn-finger domains. Expression-profiling experiments indicate that altered expression of multiple light-regulated genes in doc1 mutants can be suppressed by elevated levels of auxin caused by overexpression of an auxin biosynthetic gene, suggesting that normal auxin distribution is required to maintain low-level expression of these genes in the dark. Double mutants of tir3 with the auxin mutants pin1,pid, and axr1 display severe defects in auxin-dependent growth of the inflorescence. Chemical inhibitors of auxin transport change the intracellular localization of the auxin efflux carrier PIN1 in doc1/tir3 mutants, supporting the idea that BIG is required for normal auxin efflux.
Association Between Nuclear Lamin A/C R482Q Mutation and Partial Lipodystrophy with Hyperinsulinemia, Dyslipidemia, Hypertension, and Diabetes
Authors: Hegele Robert A. , Anderson Carol M. , Wang Jian , Jones Doreen C. , Cao Henian
Published: July 2002

Nuclear lamins A and C are encoded by LMNA and are present in terminally differentiated cells. Lamins participate in DNA replication, chromatin organization, arrangement of nuclear pores, nuclear growth, and anchorage of nuclear membranes. In several Canadian probands with partial lipodystrophy, since found to have a common ancestor, we identified a rare novel LMNA mutation, R482Q, that completely cosegregated with the partial lipodystrophy phenotype. We evaluated the relationship between quantitative metabolic phenotypes in both diabetic and nondiabetic carriers of LMNA R482Q and family controls, who were LMNA R482/R482 homozygotes. We found that when compared with LMNA R482/R482 homozygotes: (1) diabetic LMNA Q482/R482 heterozygotes had significantly higher glucose, glycosylated hemoglobin, triglycerides, insulin and C-peptide, and significantly lower HDL cholesterol; and (2) nondiabeticLMNA Q482/R482 heterozygotes had significantly higher triglycerides, insulin and C-peptide, and significantly lower HDL cholesterol. We also found that diabetic LMNA Q482/R482 heterozygotes were older and more likely to take antihypertensive medications. Thus, LMNA R482Q was associated with lipodystrophy, hyperinsulinemia, dyslipidemia, diabetes, and hypertension. The results indicate that perturbations in plasma lipids precede the plasma glucose abnormalities in LMNAQ482-associated hyperinsulinemia. Thus, rare mutations in a nuclear structural protein can be associated with markedly abnormal qualitative and quantitative metabolic phenotypes
Characterization of Flavonol Synthase and Leucoanthocyanidin Dioxygenase Genes in Arabidopsis (Further Evidence for Differential Regulation of "Early" and "Late" Genes)
Authors: Pelletier M. K. , Murrell J. R. , Shirley B. W.
Published: July 2002

As part of an ongoing investigation into the organization and regulation of the flavonoid biosynthetic pathway, two Arabidopsis thaliana expressed sequence tag (EST) clones (153O10T7 and YAY780) with high homology to leucoanthocyanidin dioxygenase (LDOX) or flavonol synthase (FLS) were identified. EST YAY780 was sequenced and found to encode a protein 49 to 78% identical to all LDOX sequences in the database. EST 153O10T7 was used to isolate a genomic clone encoding a protein with 59 to 61% sequence identity to petunia (Petunia hybrida) and potato (Solanum tuberosum) FLS. DNA blot analysis was used to screen the Arabidopsis genome for sequences related to FLS and LDOX and to determine the positions of the two clones on the RI map. The expression patterns of FLS and LDOX in etiolated seedlings moved to white light and in two putative regulatory mutants (ttg and tt8) were determined by RNA blot analysis. These studies indicate that FLS is an “early” flavonoid gene in Arabidopsis seedlings, whereas LDOX is a “late” gene. Furthermore, FLS is the first flavonoid enzyme identified in Arabidopsis that may be encoded by a gene family.
Cloning, Expression inEscherichia coli, and Characterization ofArabidopsis thalianaUMP/CMP Kinase1
Authors: Zhou Lan , Lacroute François , Thornburg Robert
Published: July 2002

A cDNA encoding theArabidopsis thaliana uridine 5′-monophosphate (UMP)/cytidine 5′-monophosphate (CMP) kinase was isolated by complementation of a Saccharomyces cerevisiae ura6 mutant. The deduced amino acid sequence of the plant UMP/CMP kinase has 50% identity with other eukaryotic UMP/CMP kinase proteins. The cDNA was subcloned into pGEX-4T-3 and expressed as a glutathione S-transferase fusion protein in Escherichia coli. Following proteolytic digestion, the plant UMP/CMP kinase was purified and analyzed for its structural and kinetic properties. The mass, N-terminal sequence, and total amino acid composition agreed with the sequence and composition predicted from the cDNA sequence. Kinetic analysis revealed that the UMP/CMP kinase preferentially uses ATP (Michaelis constant [Km] = 29 μm when UMP is the other substrate andKm = 292 μm when CMP is the other substrate) as a phosphate donor. However, both UMP (Km = 153 μm) and CMP (Km = 266 μm) were equally acceptable as the phosphate acceptor. The optimal pH for the enzyme is 6.5. P1, P5-di(adenosine-5′) pentaphosphate was found to be a competitive inhibitor of both ATP and UMP.
Characterization of Two Divergent Endo-β-1,4-Glucanase cDNA Clones Highly Expressed in the Nonclimacteric Strawberry Fruit
Authors: Llop-Tous Immaculada , Domı́nguez-Puigjaner Eva , Palomer Xavier , Vendrell Miquel
Published: July 2002

Two cDNAs clones (Cel1and Cel2) encoding divergent endo-β-1,4-glucanases (EGases) have been isolated from a cDNA library obtained from ripe strawberry (Fragaria xananassa Duch) fruit. The analysis of the amino acid sequence suggests thatCel1 and Cel2 EGases have different secondary and tertiary structures and that they differ in the presence of potential N-glycosylation sites. By in vitro translation we show that Cel1 and Cel2bear a functional signal peptide, the cleavage of which yields mature proteins of 52 and 60 kD, respectively. Phylogenetic analysis revealed that the Cel2 EGase diverged early in evolution from other plant EGases. Northern analysis showed that both EGases are highly expressed in fruit and that they have different temporal patterns of accumulation. The Cel2 EGase was expressed in green fruit, accumulating as the fruit turned from green to white and remaining at an elevated, constant level throughout fruit ripening. In contrast, the Cel1 transcript was not detected in green fruit and only a low level of expression was observed in white fruit. The level of Cel1 mRNA increased gradually during ripening, reaching a maximum in fully ripe fruit. The high levels ofCel1 and Cel2 mRNA in ripe fruit and their overlapping patterns of expression suggest that these EGases play an important role in softening during ripening. In addition, the early expression of Cel2 in green fruit, well before significant softening begins, suggests that the product of this gene may also be involved in processes other than fruit softening, e.g. cell wall expansion.
Synchrotron radiation X-ray powder diffractometer with a cylindrical imaging plate
Authors: Fujiwara A. , Ishii K. , Watanuki T. , Suematsu H. , Nakao H. , Ohwada K. , Fujii Y. , Murakami Y. , Mori T. , Kawada H. , Kikegawa T. , Shimomura O. , Matsubara T. , Hanabusa H. , Daicho S. , Kitamura S. , Katayama C.
Published: July 2002

A synchrotron radiation X-ray powder diffractometer for samples of very small amount has been developed to collect high-quality diffraction patterns under extreme conditions,i.e.at low temperature and/or high pressure. A new cylindrical imaging plate (CIP) is used as a detector, in addition to a conventional flat-type imaging plate (FIP). By using the CIP system, the diffraction data in a diffraction angle range −44 ≤ 2θ ≤ 122° are collected with a dynamic range of about 106. The alignment of the diffractometer, measurement and analysis are automatically operated by a workstation. A performance test shows that the CIP system has spatial resolution of about 0.07° with a dynamic range of 106. The diffraction pattern of a standard sample of Si measured by the CIP system has high quality; the refinement of the structure reachesRw= 3.68% even in the case of a small amount of sample (about 2 µg) and a short exposure time (60 s). Examples of experiments at low temperatures under ambient and high pressures are also presented.
Hardness of oxide films formed as a result of aluminium anode oxidation processes
Authors: Chis M. , Cojocaru M. O. , Cojocaru D. , Palmer R. A.
Published: July 2002

Factors that influence the anode oxidation processes of aluminium and its alloys are discussed. The main parameters involved in such processes have been selected and subjected to measurement under controlled experimental conditions. The effects of the variation of the chemical, electrical and thermal parameters of the aluminium anode oxidation process on the hardness level of the resulting oxide layer have been studied. In order to quantify the relationships that govern the kinetics of the anode oxidation process, these data were subjected to analysis employing a central compositional rotatory programming matrix. Parameters employed were electrolyte concentration, temperature, current density and immersion time of the product in the electrolyte to achieve a desired oxide layer. The hardness of the resulting oxide layers is discussed.
Multiple-data-set Rietveld analysis using isotopes in powder neutron diffraction. I. Accurate determination of the doping level in the ternary system NixMg1−xO, 0.005 <x< 0.1
Authors: Henry Paul F. , Weller Mark T. , Wilson Chick C.
Published: July 2002

The use of isotopes to extract precise and very accurate structural information in complex Rietveld analysis has been demonstrated by comparison of results obtained for single-data-set analysis with those from multiple-data-set single-crystallographic-model analysis of NixMg1−xO doped with various nickel isotopes. Fractional occupancies of dopants can be accurately determined down to at least the 0.5% doping level, which cannot be obtained through single-sample-data-set refinements because of correlation effects, even when a large contrast exists between the nickel isotope used and magnesium.
Small-angle neutron scattering from poly(NIPA-co-AMPS) gels
Authors: Travas-Sejdic J. , Easteal A. , Knott R. , Pedersen J.S.
Published: July 2002

The microstructure of the poly(N-isopropylacrylamide-co-acrylamido-2-methyl-1-propane sulphonic acid) gel, poly(NIPA-co-AMPS), was investigated as a function of temperature and cross-link density using the small angle neutron scattering technique. The sample temperature was varied in the range 30 to 55C. Two different behaviours of poly(NIPA-co-AMPS) gels were observed. At low temperature (30C), the magnitude of the scattered intensity increased with cross-link density suggesting that additional cross-links introduced more inhomogeneities in the gel network. At high temperatures the trend was reversed; that is the lower cross-link density, the higher the scattered intensity. Therefore, the role of cross-links at high temperature was to suppress microphase separation. The fitting of the experimental data with the Rabin and Panyukov theory indicated qualitative agreement.
Outcomes of the International Union of Crystallography Commission on Powder Diffraction Round Robin on Quantitative Phase Analysis: samples 1ato 1h
Authors: Madsen Ian C. , Scarlett Nicola V. Y. , Cranswick Lachlan M. D. , Lwin Thaung
Published: July 2002

The International Union of Crystallography (IUCr) Commission on Powder Diffraction (CPD) has sponsored a round robin on the determination of quantitative phase abundance from diffraction data. Specifically, the aims of the round robin were (i) to document the methods and strategies commonly employed in quantitative phase analysis (QPA), especially those involving powder diffraction, (ii) to assess levels of accuracy, precision and lower limits of detection, (iii) to identify specific problem areas and develop practical solutions, (iv) to formulate recommended procedures for QPA using diffraction data, and (v) to create a standard set of samples for future reference. Some of the analytical issues which have been addressed include (a) the type of analysis (integrated intensities or full-profile, Rietveld or full-profile, database of observed patterns) and (b) the type of instrument used, including geometry and radiation (X-ray, neutron or synchrotron). While the samples used in the round robin covered a wide range of analytical complexity, this paper reports the results for only the sample 1 mixtures. Sample 1 is a simple three-phase system prepared with eight different compositions covering a wide range of abundance for each phase. The component phases were chosen to minimize sample-related problems, such as the degree of crystallinity, preferred orientation and microabsorption. However, these were still issues that needed to be addressed by the analysts. The results returned indicate a great deal of variation in the ability of the participating laboratories to perform QPA of this simple three-component system. These differences result from such problems as (i) use of unsuitable reference intensity ratios, (ii) errors in whole-pattern refinement software operation and in interpretation of results, (iii) operator errors in the use of the Rietveld method, often arising from a lack of crystallographic understanding, and (iv) application of excessive microabsorption correction. Another major area for concern is the calculation of errors in phase abundance determination, with wide variations in reported values between participants. Few details of methodology used to derive these errors were supplied and many participants provided no measure of error at all.
New contrasts of piezoelectric devices using synchrotron stroboscopic section topography at ESRF
Authors: Capelle B. , Détaint J. , Epelboin Y.
Published: July 2002

The propagation modes of ultra-acoustic waves in quartz planar resonators have been studied by means of stroboscopic section topographs at ESRF. The images present a number of internal lines inside the section that allow a quantitative analysis of the vibration modes. When the excitation level increases, the shape of the lines enables the study of the dumping of the vibration along the surface of the device. Such analysis was made possible because of the small divergence of the white beam delivered by a third-generation synchrotron source.
Texture analysis with high-energy synchrotron radiation
Authors: Wcislak L. , Klein H. , Bunge H. J. , Garbe U. , Tschentscher T. , Schneider J. R.
Published: July 2002

Texture measurement with short-wave X-ray synchrotron radiation in the range of λ ≃ 0.1 Å is described. The measurements were carried out with the multipurpose diffraction instrument at the high-field wiggler, high-energy beamline BW5 at HASYLAB. The instrument was equipped with an on-line image-plate area detector for diffraction-image registration and a Eulerian cradle for sample orientation. The particular features of texture measurement with the BW5 instrument are: good resolution in the Bragg angle, extremely high angular resolution in crystal orientation (pole-figure angles) and particularly high penetration depth of several millimetres to centimetres, comparable with that of neutrons but at high spatial resolution. Several examples illustrate the particular advantages of this method for texture studies using large or encased samples (in situstudies in complicated environments, such as cryostats, furnaces, vacuum or pressure chambers, with no serious window problems). This allows, among others, non-destructive texture analysis in technological parts and whole components. Because of the extremely high beam intensity (short exposure times) compared with all other methods of texture measurement, the new technique is particularly suited for the study of large sample series (as is often necessary in industrial applications).
Unbiased analysis of neutron and X-ray reflectivity data by an evolution strategy
Authors: Politsch Erich , Cevc Gregor
Published: July 2002

A new method for the unbiased determination of scattering length density (SLD) profiles from neutron or X-ray reflectograms is presented, based on an evolution strategy. In contrast to existing methods, the new approach uses no constraints that could influence the fit result improperly. While it is widely agreed that SLD profile oscillations with small wavelength and small amplitude cannot be resolved, randomly occurring long-wavelength oscillations have been neglected to date despite the fact that such oscillations can tremendously affect the calculated SLD profile. No easy remedy exists for this problem within the framework of conventional reflectogram analysis methods. The analytical approach proposed in this work offers a solution based on the recognition that each perturbation which leads to an indistinguishable reflectivity has a negative pendant. Averaging of numerous different, randomly perturbed, profiles therefore cancels out random deviations and accentuates reliable features. Moreover, the resulting averaged free-form fit has maximum (information) entropy. The performance of the novel approach is demonstrated by analysing complex molecular arrangements at an air–water interface and comparing the results with prior evaluations.
Helium temperatures in a four-circle neutron diffractometer
Authors: Herbert I. R. , Campbell S. J.
Published: July 2002

The cooling of single-crystal samples to helium temperatures within a four-circle neutron diffractometer has been achieved by a novel continuous-flow system. The system relies solely on helium for its cooling power with two flow circuits being used. The first delivers liquid to a reservoir cryostat of capacity 1–4 l located close to the Eulerian cradle of the diffractometer and the second draws the refrigerant from this cryostat via a flexible transfer tube into the sample region of a compact cooling unit mounted off the cradle. This arrangement allows unhindered motion of the diffractometer circles for sample temperature operation in the range 3.9–300 K. The system requires a total helium flow of 1.0 l h−1 to maintain a temperature of 20±0.1 K, decreasing to 0.5 l h−1 at higher temperatures.
Quantitative microanalysis of cristobalite by X-ray powder diffraction
Authors: Bye E.
Published: July 2002

A method for the quantitative X-ray diffraction analysis of microgram amounts of cristobalite is presented. Dust samples (1–2 mg) distributed on Nuclepore membrane filters are placed upon a silver membrane filter in a rotating sample holder. The diffraction pattern intensities of the silver filter are used to correct for absorption and for long-term instrumental drift. The detection limit is 10 μg with an accuracy of ± 10% at the 0.3 mg level.
Relationship of crystallographic polarity to piezoelectric, pyroelectric and chemical etching in Li2GeO3 and LiGaO2 single crystals
Authors: Bhalla A. S. , Tongson L. L. , Newnham R. E.
Published: July 2002

Absolute assignment of the atomic planes of Li2GeO3 and LiGaO2 is made by ion surface scattering (ISS) and the crystallographic polarity is defined. Pyroelectric coefficients p
3 and the piezoelectric constants d
33 of lithium metagermanate and lithium gallate are determined. Pyroelectric and piezoelectric coefficient signs when defined on the crystallographic sign convention of the axes are negative and positive, respectively. The results are correlated with chemical etching studies.
G-TDSCOR: one-phonon TDS corrections for measured integrated Bragg intensities
Authors: Sakata M. , Stevenson A. W. , Harada J.
Published: July 2002

A computer program for calculating the one-phonon thermal diffuse scattering (TDS) contribution to observed integrated intensities of Bragg reflections from single crystals has been written. The program is based on a general formula [Harada & Sakata (1974). Acta Cryst. A30, 77–82; Sakata & Harada (1976). Acta Cryst. A35, 426–433] which is applicable to any crystal system if elastic constants are available. The volume integral with respect to the wavevector, over the region swept out around the reciprocal-lattice point by the counter in the course of a measurement, has been simplified by use of the spherical volume approximation (SVA). Use of the SVA greatly reduces computing time for the case of large data sets. Comparison of the results with those obtained without using the SVA is given and the limitations of the SVA are pointed out.
A new optical method and apparatus `HAUP' for measuring simultaneously optical activity and birefringence of crystals. II. Application to triglycine–sulphuric acid (NH2CH2CO2H)3.H2SO4
Authors: Kobayashi J. , Uesu Y. , Takehara H.
Published: July 2002

As the test for the utility of HAUP, simultaneous determinations of birefringence, optical activity, and rotation of the indicatrix, and electrooptic, and electrogyration coefficients were made for both paraelectric and ferroelectric states of triglycine-sulfuric acid, 3C2H5NO2.H2SO4. In the ferroelectric state, the hysteresis loop of the gyration tensor g
22 was clearly observed. Electrooptic and electrogyration coefficients referred to polarization are found to be nearly independent of temperature over the paraelectric and ferroelectric states. It is important to note that gyration is more largely induced than birefringence under lower electric fields. This fact, contrary to the previous belief, indicates that simultaneous determinations of gyration and birefringence are indispensable for the correct evaluations of the optical properties of crystals.
Texture of extruded uranium alloy by neutron diffraction
Authors: Choi C. S. , Prask H. J.
Published: July 2002

The pole-density distributions of two hydrostatically extruded samples, a U–0.75 wt.% Ti alloy and a U–0.75 wt % Ti/W composite alloy, were studied by neutron diffraction methods. Analysis of U 112, U 131 and U 111 pole figures revealed that the α-U phases of both samples possess a [010]/[340] duplex fiber texture with a probability ratio of approximately 2.8:1 in favor of the [010] direction. The W phase of the composite sample had a [110] fiber texture. The orientation distribution profiles of the fiber axes obtained from the rocking curves (as a function of the tilt angle) were represented best by a Gaussian–Lorentzian combination function. The full widths at half maximum of the distributions were approximately 21, 11, and 5° for the U [010], U [340] and W [110] fiber axes, respectively.
Etude de la structure d'une multicouche synthétique par la méthode de diffraction par dispersion d'énergie des rayons X
Authors: Malaurent J. C. , Duval H. , Fert A.
Published: July 2002

An energy-scanning X-ray diffraction technique is used to study a synthetic periodic multilayer structure with two amorphous components. The source was the Bremsstrahlung from the X-ray tube, and the detector was a silicon–lithium diode. Experimental results obtained for a multilayer PdSi/MgCu with large period show a deviation from the classical Bragg's law. The deviation is produced by the variation of the refractive index of the multilayer with the wavelength of the incident X-ray. The period d was determined to within 1%. A measure of the refraction index enabled an estimate to be made of the width of each layer. It was also possible to estimate the fluctuation of the period along the multilayer from the full widths of the diffracted Bragg peaks at maximum intensities. The limits of the method are discussed.
Residual stress analysis using overlapping diffraction peaks. Case of textured cubic materials
Authors: Brakman C. M.
Published: July 2002

Residual stresses in polycrystalline materials can be determined from the 2θ shift of a reflection peak's line profile. Recently, multiple reflections have been used for residual stress analysis in single-phase textured cubic materials. Analogously, residual stresses in two-phase materials could be determined from overlapping peaks of both phases. Equations are derived for residual stress analysis using partially or completely overlapping diffraction peaks. Mainly textured cubic materials are considered. It is shown that the so-called quasi-isotropic diffraction elastic constants become connected to texture-dependent quantities. In the examples treated the calculated diffraction strains of three multiple reflections exhibit only small nonlinearities although the intensities oscillate strongly.
High-speed X-ray diffraction and in situ resistivity measurements at temperatures of 100 to 1000 K
Authors: Angilello J. , Thompson R. D. , Tu K. N.
Published: July 2002

A system has been constructed which uses a primary-beam focusing monochromator Debye–Scherrer X-ray method to perform simultaneously in situ X-ray diffraction and resistivity measurements at temperatures of 100 to 1000 K. The Inel curved linear detector, which is capable of recording 120° of 20 angle without moving the detector, makes the Debye–Scherrer geometry possible for high-speed dynamic studies. The angular resolution of this system is sufficient to observe the separation of a mixture of tungsten and molybdenum powders. The sensitivity of the system makes it possible to record the diffraction pattern from a 100 Å gold film. The sheet resistivity of the sample can be recorded simultaneously to provide a structure-property correlation. Comparisons with other X-ray diffraction methods using thin films are discussed.
Calculation of the crystal orientation distribution function from synchrotron radiation experimental data
Authors: Szpunar J. A. , Blandford P. , Hinz D. C.
Published: July 2002

Series-expansion coefficients for an orientation distribution function (ODF) of cold-rolled aluminium sheet were calculated from the intensity of Debye–Scherrer rings obtained in an experiment using synchrotron radiation. Calculated and observed pole figures demonstrate that a sufficiently good approximation to the ODF is obtained from coefficients calculated to l = 8.
X-ray study of CuGa
x
In1−x
Se2 solid solutions
Authors: Suri D. K. , Nagpal K. C. , Chadha G. K.
Published: July 2002

The semiconducting compound CuGa
x
In1 − x
Se2 crystallizes in the chalcopyrite structure (space group I{\bar 4}2d, Z = 4). The X-ray powder data for x = 1, 0.75, 0.6, 0.5, 0.4, 0.25 and 0.0 have been collected and it is found that the lattice parameters a and c and their ratio c/a vary linearly with x. Thus the composition of any chalcopyrite in the pseudo-binary system CuGaSe2 and CuInSe2 can be obtained from the accurate lattice parameters. The crystallite size determined from the (112) plane is minimum for x = 0.50 (~ 1000 Å) and away from x = 0.50 it increases. A value of u = 0.240 (5) has been established for fixing the Se-atom positions in the CuGa0.5In0.5Se2 solid solution. The JCPDS Diffraction File No. for CuInSe2 is 40-1487 and for CuGa0.5In0.5Se2 is 40-1488.
The internal structure of layered colloidal particles determined with SANS
Authors: Duits M. H. G. , May R. P. , de Kruif C. G.
Published: July 2002

Small-angle neutron scattering measurements at various contrasts were performed on dilute colloidal silica dispersions in order to resolve the internal structure of the particles. The particles were prepared by outgrowth of a commercially available silica core, followed by an esterification of the surface silanol groups with stearyl alcohol. Variation of the scattering contrast was achieved by using mixtures of 1H12- and 2H12-cyclohexane as dispersing medium. The scattering data were interpreted as originating from a polydisperse system of spherical three-layer particles. Model parameters were optimized sequentially, applying an increasing number of constraints. Good agreement between experimental and calculated scattering curves is obtained, even at higher K values and low contrasts. In comparison with other particles in the same size range, these silica particles represent a very suitable model system for small-angle scattering experiments at higher volume fractions.
32 bit personal computer version of the DIRECT-SEARCHER system
Authors: Okada K. , Koyama H.
Published: July 2002

A new version of DIRECT*SEARCHER (DIRECT-SEARCHER automatic system) for personal computers (PC) consisting of several crystallographic programs has been developed for automatic structure analysis of organic compounds as an innovation of the DS*SYSTEM [Koyama & Okada (1975). Acta Cryst. A31, S18]. Each program is improved and rewritten in Fortran77 for the 32 bit PC. The PC version of DS*SYSTEM is used by organic chemists rather than professional crystallographers.
High-energy resolution in X-ray scattering with the spectrometer INELAX. I. The principles and the test instrument
Authors: Burkel E. , Dorner B. , Illini Th. , Peisl J.
Published: July 2002

Very high-energy resolution measurements using X-rays can be achieved by extreme backreflection (Bragg angle close to 90°) from perfect crystals. This technique, combined with the high intensity of X-rays emitted by synchrotron-radiation sources, allowed the development of the instrument INELAX for inelastic scattering experiments. The principles and test results are discussed.
The determination of unit-cell parameters from Laue diffraction patterns using their gnomonic projections
Authors: Carr P. D. , Cruickshank D. W. J. , Harding M. M.
Published: July 2002

A method is described whereby the unit cell of a crystal and its orientation can be determined from a single Laue diffraction pattern (in transmission). The axial ratios and interaxial angles can be determined precisely, but the absolute scaling of the cell depends upon the accuracy with which the minimum wavelength for the experiment is known. Several examples are given.