bluuebunny/crossref_metadata_2025 huggingface dataset:
Epitaxial CuIn1–xGaxSe2/ZnS heterostructures grown on (001)GaAs by co‐evaporation
Authors: Roussak Liudmila , Wagner Gerald , Makhova Liudmila , Konovalov Igor
Published: February 2009

Epitaxial heterostructures of ZnS/Cu(In,Ga)Se2 have been successfully grown on (001)‐oriented GaAs substrates by co‐evaporation during one single deposition process. The influence of the growth conditions on the compositional, structural and morphological properties of thin Cu(In,Ga)Se2 (CIGSe) and ZnS films was investigated. It was found, the stoichiometry of the CIGSe films strongly depends on the pSe/(pCu+pIn+pGa)‐ratio. A large Se evaporation rate is found to avoid the segregation of a Cu‐rich secondary phase. The interfaces between ZnS and Cu(In,Ga)Se2 as well as GaAs und CIGSe were examined by TEM‐EDX, TEM and HRTEM. At a substrate temperature of about 250 °C it is possible to achieve quite chemically and structurally sharp ZnS/Cu(In,Ga)Se2 heterojunctions. The dominant structural defects in both the CIGSe and ZnS films are dislocations, stacking faults, twins and diffusion‐induced defects at the GaAs/CIGSe interface. The density of the latter ones can be appreciably reduced by an additional pre‐treatment of the GaAs substrate surface with Na2S solution. Despite the relatively high crystalline quality of the epitaxial double‐heterostructures, due to the high resistivity and high compensation of the ZnS as well as the modification of the ZnS/Cu(In,Ga)Se2 interface it was difficult to produce efficient CIGSe based photovoltaic devices. Moreover, due to the diffusion of copper from the CIGSe film into the GaAs substrate an undesired additional p‐n junction is formed inside the GaAs. It is the main reason that the GaAs/CIGSe/ZnS double‐heterostructures formed by the co‐evaporation process and described here cannot be used for an effective photovoltaic application. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐situ XRD on formation reactions of Cu2ZnSnS4 thin films
Authors: Weber Alfons , Mainz Roland , Unold Thomas , Schorr Susan , Schock Hans‐Werner
Published: February 2009

Starting from stacked binary sulphide precursor layers with copper‐ and zinc‐rich composition the formation of Cu2ZnSnS4 (kesterite) has been investigated. Precursors with different layer thicknesses were deposited to evaluate the influence of material transport on the reaction kinetics. During annealing experiments the formation of kesterite in the different precursors was monitored by in‐situ energy‐dispersive X‐ray diffraction. An evaluation of the reaction rates revealed that at a temperature of 500 °C a kesterite film of 2 μm thickness can be formed within few minutes. The long annealing times reported in literature for well‐performing kesterite photovoltaic absorbers do therefore not owe to a general kinetic limitation for the formation of kesterite thin films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural analysis of lithium lanthanum titanate with perovskite structure
Authors: Ohara Koji , Kawakita Yukinobu , Temleitner László , Pusztai László , Kohara Shinji , Jono Atsushi , Shimakura Hironori , Inoue Naoki , Takeda Shin'ichi
Published: February 2009

Neutron and high‐energy X‐ray diffraction analysis of polycrystalline La4/3‐xLi3xTi2O6 have been performed to clarify the extent of disorder of the distribution of La and Li ions and to understand the relation of these distributions to ionic conduction. The distributions of the La and Li ions in a 10 × 10 × 20 cubic box (i.e., 10 × 10 × 10 unit cell) super‐structure, in which Ti and O atoms are fixed onto their regular sites, were obtained by the reverse Monte Carlo (RMC) structural modelling of both diffraction data sets. When the occupancy of La ions in the planes perpendicular to the c‐axis is analysed, one can find a La‐rich and La‐poor layers alternating, which is consistent with the results of earlier Rietveld analysis (Stramare et al., Chem. Mater. 15, 3974 (2003) [1]). Of particular interest, the Li ions are found mainly on the interstitial sites between the O‐3 triangle plane of the TiO6 octahedron and a La ion, which is different from the earlier work (Yashima et al., J. Am. Chem. Soc. 127, 3491 (2005) [2]). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modulation of drug resistance in staphylococcus aureus by a kaempferol glycoside from herissantia tiubae (malvaceae)
Authors: Falcão‐Silva Vivyanne S. , Silva Davi A. , Souza Maria de Fátima V. , Siqueira‐Junior José P.
Published: February 2009

In an ongoing project to evaluate natural compounds isolated from plants from the Brazilian biodiversity as modulators of antibiotic resistance, kaempferol‐3‐O‐β‐d‐(6″‐E‐p‐coumaroyl) glucopyranoside (tiliroside), isolated from Herissantia tiubae (Malvaceae) was investigated using the strain SA‐1199B of Staphylococcus aureus, which overexpresses the norA gene encoding the NorA efflux protein which extrudes hydrophilic fluorquinolones and some biocides, such as benzalkonium chloride, cetrimide, acriflavine and ethidium bromide. The minimum inhibitory concentrations (MICs) of the antibiotics and biocides were determined by the microdilution assay in the absence and in the presence of sub‐inhibitory concentration of tiliroside. Although tiliroside did not display relevant antibacterial activity (MIC = 256 µg/mL), it modulated the activity of antibiotics, i.e. in combination with antibiotics a reduction in the MIC was observed for norfloxacin (16‐fold), ciprofloxacin (16‐fold), lomefloxacin (four‐fold) and ofloxacin (two‐fold), and an impressive reduction in the MICs for the biocides (up to 128‐fold). The results presented here represent the first report of a kaempferol glycoside as a putative efflux pump inhibitor in bacteria. The present finding indicates that H. tiubae (and broadly Malvaceae) could serve as a source of plant‐derived natural products that modulate bacterial resistance, i.e. a source of potential adjuvants of antibiotics. Copyright © 2009 John Wiley & Sons, Ltd.
Characterization of different poly(2‐ethyl‐2‐oxazoline)s via matrix‐assisted laser desorption/ionization time‐of‐flight tandem mass spectrometry
Authors: Baumgaertel Anja , Weber Christine , Knop Katrin , Crecelius Anna , Schubert Ulrich S.
Published: February 2009

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) coupled with CID (collision‐induced dissociation) has been used for the detailed characterization of two poly(2‐ethyl‐2‐oxazoline)s as part of a continuing study of synthetic polymers by MALDI‐TOF MS/MS. These experiments provided information about the variety of fragmentation pathways for poly(oxazoline)s. It was possible to show that, in addition to the eliminations of small molecules, like ethene and hydrogen, the McLafferty rearrangement is also a possible fragmentation route. A library of fragmentation pathways for synthetic polymers was also constructed and such a library should enable the fast and automated data analysis of polymers in the future. Copyright © 2009 John Wiley & Sons, Ltd.
Global set stabilization of the spacecraft attitude control problem based on quaternion
Authors: Li Shihua , Ding Shihong , Li Qi
Published: February 2009

In this paper, we develop a global set stabilization method for the attitude control problem of spacecraft system based on quaternion. The control law that uses both optimal control and finite‐time control techniques can globally stabilize the attitude of spacecraft system to a set of equilibria. First, for the kinematic subsystem, we design a virtual optimal angular velocity. To obtain the global minimum of the performance index, this optimal angular velocity is only discontinuous in initial values. It can be regarded as a combination of open loop control and closed loop control. Then for the dynamic subsystem, we design a finite‐time control law that can force the angular velocity to track the virtual optimal angular velocity. It is proved that the closed loop system satisfies global set stability in the absence of disturbances. In the presence of disturbances, the system trajectory will converge to a neighborhood of the equilibrium set. Rigorous analysis shows that by introducing finite‐time control techniques, the closed loop system possesses a better disturbance rejection property. The control method is more natural and energy‐efficient. The effectiveness of the proposed method is demonstrated by simulation results. Copyright © 2009 John Wiley & Sons, Ltd.
A model‐based analysis of meander restoration
Authors: Krapesch Gerald , Tritthart Michael , Habersack Helmut
Published: February 2009

Meander reconnection is becoming a widely applied river restoration measure, aiming to enhance the ecological status of river systems. Based on a physical model study and a 3D hydrodynamic‐numerical simulation, the effects of different forms of meander reconnections on flow dynamics, water level and river morphology are investigated in present study including retention of the old main channel for flood protection when the bankfull discharge is exceeded. The distribution of total discharge between the reconnected meander bend and the flood channel during floods decreases flow velocity and bed shear stress and leads to aggradation. At higher discharges, the flow velocity decreases in the meander bend whereas it increases in the flood channel. The controlling parameter for flow diversion—hence for flow velocity and bed shear stress—is the elevation of the ramp diverting the flow.

Using the hydrodynamic model RSim‐3D a particle tracing study simulated the trajectories of conservative particles at six vertical levels. The vertical movements of the particles on trajectories going through the reconnected meander were investigated by calculating the number of level changes of each particle. This novel approach in simulating particle movement in channels facilitating qualitative decision‐making in the framework of river restoration issues. In particular, it reveals information regarding heterogeneity and turbulence of the water and also nutrient movements under variable flow conditions and can thus help answer restoration‐related ecological questions. Copyright © 2009 John Wiley & Sons, Ltd.
Scientific design strategy for promoting sustainable sediment management: the case of the Magra River (Central‐Northern Italy)
Authors: Rinaldi Massimo , Simoncini Cristina , Piégay Hervé
Published: February 2009

The Magra River (Central‐Northern Italy) and its main tributary, the Vara River, have been heavily affected by sediment mining and other human disturbances that have caused channel incision and a series of associated negative environmental effects. As a consequence, the Basin Authority of Magra River has recently implemented a new river management policy based on an understanding and analysis of geomorphic processes. This paper describes and illustrates a methodology that defines a scientifically‐based strategy for promoting future sustainable management of sediment and channel processes within this catchment. The methodology is based on a diagnosis which incorporates retrospective analyses of channel geometry, causes of changes and hydraulic sediment budgets to evaluate potential sediment transport. All these data are summarized using a multi‐criteria approach to develop an overall design strategy for medium‐term (i.e. some decades) bed sediment management. A practical methodology to identify potential sources of sediment at the catchment scale and to promote sediment delivery is also described. Finally, a ‘map of strategies for sediment management’ is presented, which synthesises all the aspects studied (morphological evolution, sediment budgets and considerations of potential sediment recharge). Copyright © 2009 John Wiley & Sons, Ltd.
Embedded security framework for integrated classical and quantum cryptography services in optical burst switching networks
Authors: Chen Yuhua , Verma Pramode K. , Kak Subhash
Published: February 2009

Optical burst switching (OBS) is the most promising optical switching technology for the future Internet, but it suffers from security vulnerabilities. In this paper, we propose to embed a security framework which incorporates the strengths of classical and the emerging quantum cryptography techniques in the native OBS network architecture, providing a means to make the future Internet secure from the ground up. The proposed embedded security architecture allows the best suited classical and quantum cryptography techniques to be deployed, making it possible to offer robust security. The security of quantum cryptography is based on the inherent randomness in quantum phenomena. The application of quantum techniques to optical networks is ideally suited to the problem because photons, which carry information in optical modality, are quantum objects. Since the well‐known BB84 quantum cryptography protocol is susceptible to siphoning attacks on the multiple photons emitted by practical sources, we propose to use a new 3‐stage quantum cryptography protocol which is immune to siphoning attacks, as it is based on random rotations of the polarization vector. This would allow multiple photons to be used in the quantum key exchange, and make it feasible to extend quantum cryptography services beyond trusted routers. Copyright © 2009 John Wiley & Sons, Ltd.
Nicotine sensitization and analysis of brain‐derived neurotrophic factor in adolescent ß‐arrestin‐2 knockout mice
Authors: Correll Jennifer A. , Noel Daniel M. , Sheppard A. Brianna , Thompson Kimberly N. , Li Yi , Yin Deling , Brown Russell W.
Published: February 2009

Nicotine sensitization and levels of brain‐derived neurotrophic factor (BDNF) were analyzed in adolescent ß‐arrestin‐2 knockout (ßA‐2 KO) and wild type (WT) mice. The ß‐arrestin‐2 protein has been shown to be important in G‐protein hydrolysis and receptor internalization. Four‐ to five‐week‐old adolescent ßA‐2 KO and WT C57/Bl6 mice were administered either nicotine (0.5 mg/kg free base) or saline 10 min before being placed into a locomotor arena on each of 7 (Experiment 1) or 14 (Experiment 2) consecutive days. A nicotine challenge was given 7 days after sensitization was complete. In Experiment 1, ßA‐2 KO mice administered nicotine or saline and WT mice administered nicotine demonstrated significant hypoactivity during early in testing, and neither WT nor ßA‐2 KO mice administered nicotine demonstrated sensitization. On the nicotine challenge, WT mice administered nicotine demonstrated significantly higher activity levels compared to all groups, and this same group demonstrated significantly higher levels of accumbal BDNF compared to all groups. In Experiment 2, ßA‐2 KO mice were again hypoactive compared to WT mice, whereas WT mice administered nicotine demonstrated significant hypoactivity during initial testing and significantly higher levels of activity compared to all other groups late in testing. On the nicotine challenge, WT mice that received nicotine demonstrated a significant increase in activity compared to all groups, and showed increased accumbal BDNF compared to all groups. These results show that the ß‐arrestin‐2 protein is important in induction and expression of nicotine sensitization as well as nicotine's effects on accumbal BDNF. Synapse 63:510–519, 2009. © 2009 Wiley‐Liss, Inc.
Hydromagnetic effects on the flow of a micropolar fluid in a diverging channel
Authors: Srinivasacharya D. , Shiferaw M.
Published: February 2009

Steady flow of an incompressible and electrically conducting micropolar fluid through a diverging channel is studied. The flow is subjected to a uniform magnetic field perpendicular to the flow direction. Perturbation solutions have been obtained for the velocity and microrotation components in terms of effective Reynolds number. The profiles of velocity and microrotation components are presented for different micropolar fluid parameters and magnetic parameter. The influence of magnetic parameter on the pressure gradient is also studied.
Modeling FGM brake disk against global thermoelastic instability (hot‐spot)
Authors: Hernik S.
Published: February 2009

This paper deals with study of the global thermoelastic instability of brake disk made of either the isotropic homogeneous metal matrix composite (MMC) or the isotropic inhomogeneous functionally graded material composite (FGM). The main idea of the FGM composite is a smooth variation of material properties due to continuous change in microstructure. The estimates in diffusion equation are characterized both by non‐stationary heat flux and non‐stationary heat convection terms enhanced by the characteristic frictional heat sources. Global instability is characterized by the Schaefer–Papkovich condition. Application of functionally graded A356R‐based composite to brake disk structure prevents loss of global stability in contrast with homogeneous A356R composite and stainless steel ASTM321 brake disk which guaranties safety and durability of the braking system.
A Bayesian Semiparametric Item Response Model with Dirichlet Process Priors
Authors: Miyazaki Kei , Hoshino Takahiro
Published: February 2009

In Item Response Theory (IRT), item characteristic curves (ICCs) are illustrated through logistic models or normal ogive models, and the probability that examinees give the correct answer is usually a monotonically increasing function of their ability parameters. However, since only limited patterns of shapes can be obtained from logistic models or normal ogive models, there is a possibility that the model applied does not fit the data. As a result, the existing method can be rejected because it cannot deal with various item response patterns.

To overcome these problems, we propose a new semiparametric IRT model using a Dirichlet process mixture logistic distribution. Our method does not rely on assumptions but only requires that the ICCs be a monotonically nondecreasing function; that is, our method can deal with more types of item response patterns than the existing methods, such as the one-parameter normal ogive models or the two- or three-parameter logistic models.

We conducted two simulation studies whose results indicate that the proposed method can express more patterns of shapes for ICCs and can estimate the ability parameters more accurately than the existing parametric and nonparametric methods. The proposed method has also been applied to Facial Expression Recognition data with noteworthy results.
Nanometer Sized Silver Particles Embedded Silica Particles—Spray Method
Authors: Gnana kumar G , Karunagaran B , Nahm KeeSuk , Nimma Elizabeth R
Published: February 2009

Spherical shaped, nanometer to micro meter sized silica particles were prepared in a homogeneous nature by spray technique. Silver nanoparticles were produced over the surface of the silica grains in a harmonized manner. The size of silver and silica particles was effectively controlled by the precursors and catalysts. The electrostatic repulsion among the silica spheres and the electro static attraction between silica spheres and silver particles make the synchronized structure of the synthesized particles and the morphological images are revealed by transmission electron microscope. The silver ions are reduced by sodium borohydride. Infra red spectroscopy and X-ray photoelectron spectroscopy analysis confirm the formation of silver–silica composite particles. Thermal stability of the prepared particles obtained from thermal analysis ensures its higher temperature applications. The resultant silver embedded silica particles can be easily suspended in diverse solvents and would be useful for variety of applications.
Body Compositional Changes and Growth Alteration in Chicks from Hens Fed Conjugated Linoleic Acid
Authors: Leone Vanessa A. , Worzalla Sharon P. , Cook Mark E.
Published: February 2009

Effects of feeding conjugated linoleic acid (CLA) to hens on progeny chick development and composition at hatch (NHC) and three weeks of age (TWC) were assessed. CLA (0 or 0.5%, composed of mixed isomers of cis‐9,trans‐11 or trans‐10,cis‐12‐CLA) was fed to hens with either safflower (SO) or olive oil (OO) (3 or 3.5%) to assure successful hatch for 2 weeks prior to collection for incubation. Maternal CLA feeding had no effect on hatchability, but improved egg fertility (p < 0.05). Maternal feeding of CLA with SO increased 21 day‐old progeny growth, while CLA with OO decreased growth (oil*CLA, p < 0.05). In 25 day‐old chicks (TWC), but not NHC, maternal CLA decreased the proportion of total body water (p < 0.05) and increased body ash (p < 0.05). While monounsaturated fatty acids were decreased and saturated fatty acids increased in eggs and NHC from hens fed CLA, no differences in fatty acid composition were observed in chicks at 25 days of age from hens fed CLA. Maternal CLA feeding resulted in the presence of c9,t11 and t10,c12‐CLA in NHC, but only c9,t11 in the TWC. In conclusion, hens fed CLA led to improved fertility and altered body composition at 3 weeks of age.
Rationality and Rationalistic Choice in the California Recall
Authors: Michael Alvarez R. , Roderick Kiewiet D.
Published: February 2009

The California recall election of 2003 provides an excellent setting for investigating voter rationality and certain forms of sophisticated voting. In a pre-election telephone survey, 1,500 registered voters were asked to make pairwise comparisons between the major candidates, and their responses were combined to infer preferences. Individuals’ preference orderings over the major candidates rarely exhibited intransitivity. The patterns of tactical voting observed in the replacement part of the recall election were consistent with the declining rate hypothesis. Voters also engaged in ‘hedge voting’ on the recall question itself. The results suggest that voters’ decisions are ‘rationalistic’: while voters are consistent in forming utility-based preference rankings and choosing on that basis, their voting strategies do not incorporate probability assessments in a realistic, consistent fashion, if at all.
Fixation probability of beneficial mutations in a fluctuating population
Authors: ENGEN STEINAR , LANDE RUSSELL , SÆTHER BERNT-ERIK
Published: February 2009

We compute an accurate approximation to the probability of fixation for a beneficial mutation in a population fluctuating with a stationary distribution of population size. The population dynamics are described by the theta-logistic model with environmental variance, assuming that the population size is large enough to ignore demographic variance. We show that stochastic fluctuations of population size reduce the probability of fixation. However, it is not the magnitude of the population fluctuationsper sethat creates this reduction. Only the environmental variance has a substantial effect on the probability of fixation. The strength of density dependence (or expected return time to equilibrium) and the functional form of density-regulation, given by the parameter θ in the theta-logistic model, have little effect on the fixation probability. Effective population size based on harmonic mean population size will therefore underestimate the expected fixation rate of beneficial mutations in fluctuating populations.
Triosephosphate isomerase activity-deficient mice show haemolytic anaemia in homozygous condition
Authors: PRETSCH WALTER
Published: February 2009

A triosephosphate isomerase (TPI) mutant,Tpi1a-m6Neu, with approximately 57% residual enzyme activity in blood compared with wild-type was detected among offspring of triethylenemelamine-treated male mice. Homozygous mutants with about 13% residual enzyme activity were recovered in progeny ofinter sematings of heterozygotes. The loss of TPI activity was evident both in blood and in other tissue extracts. Values for haematocrit, haemoglobin, number of red blood cells (RBC), mean corpuscular volume of RBC, mean corpuscular haemoglobin concentration and spleen weight show significant differences between wild-type animals and homozygous mutants. Sequence analysis revealed a substitution (c.A149G) in theTpi1gene. This mutation results in an Asp to Gly substitution at codon 49 in exon 2 at a highly conserved position located in the functional domain of the TPI protein which is responsible for the correct dimerization of the subunits. As a potential animal model,Tpi1a-m6Neurepresents the only available TPI-deficient homozygous viable mouse mutation.
Scrapie-resistant sheep show certain coat colour characteristics
Authors: SAWALHA R. M. , BELL L. , BROTHERSTONE S. , WHITE I. , WILSON A. J. , VILLANUEVA B.
Published: February 2009

Susceptibility to scrapie is known to be associated with polymorphisms at the prion protein (PrP) gene, and this association is the basis of current selective programmes implemented to control scrapie in many countries. However, these programmes might have unintended consequences for other traits that might be associated withPrPgenotype. The objective of this study was to investigate the relationship betweenPrPgenotype and coat colour characteristics in two UK native sheep breeds valued for their distinctive coat colour patterns. Coat colour pattern, darkness and spotting andPrPgenotype records were available for 11 674 Badgerfaced Welsh Mountain and 2338 Shetland sheep. The data were analysed with a log–linear model using maximum likelihood. Results showed a strong significant association ofPrPgenotype with coat colour pattern in Badgerfaced Welsh Mountain and Shetland sheep and with the presence of white spotting in Shetland sheep. Animals with the ARR/ARR genotype (the most scrapie resistant) had higher odds of having a light dorsum and a dark abdomen than the reverse pattern. The implication of these associations is that selection to increase resistance to scrapie based only onPrPgenotype could result in change in morphological diversity and affect other associated traits such as fitness.
On a logical difficulty in the directed mutation debate
Authors: ZHENG QI
Published: February 2009

This paper calls attention to an overlooked logical difficulty that has impeded the directed mutation debate for over half a century. It further suggests that the random mutation hypothesis be regarded at present as a null hypothesis in evolutionary biology.
Molecular organization of 5S rDNA in sharks of the genusRhizoprionodon: insights into the evolutionary dynamics of 5S rDNA in vertebrate genomes
Authors: PINHAL DANILLO , ARAKI CARLOS S. , GADIG OTTO B. F. , MARTINS CESAR
Published: February 2009

In this study, we attempted a molecular characterization of the 5S rDNA in two closely related species of carcharhiniform sharks,Rhizoprionodon lalandiiandRhizoprionodon porosus, as well as a further comparative analysis of available data on lampreys, several fish groups and other vertebrates. Our data show thatRhizoprionodonsharks carry two 5S rDNA classes in their genomes: a short repeat class (termed class I) composed of ~185 bp repeats, and a large repeat class (termed class II) arrayed in ~465 bp units. These classes were differentiated by several base substitutions in the 5S coding region and by completely distinct non-transcribed spacers (NTS). In class II, both species showed a similar composition for both the gene coding region and the NTS region. In contrast, class I varied extensively both within and between the two shark species. A comparative analysis of 5S rRNA gene sequences of elasmobranchs and other vertebrates showed that class I is closely related to the bony fishes, whereas the class II gene formed a separate cartilaginous clade. The presence of two variant classes of 5S rDNA in sharks likely maintains the tendency for dual ribosomal classes observed in other fish species. The present data regarding the 5S rDNA organization provide insights into the dynamics and evolution of this multigene family in the fish genome, and they may also be useful in clarifying aspects of vertebrate genome evolution.
The career of Aldhelm
Authors: Lapidge Michael
Published: February 2009

A re-examination of the evidence on which the life of Aldhelm can be reconstructed. Attention is focussed initially on Aldhelm's links with the royal family of Wessex, and the relationship between the West Saxon and Northumbrian royal houses is used to throw light on the period in Aldhelm's early life when he was fostered along with Aldfrith on Iona. The same relationship is reflected thereafter in Aldhelm's ties with Aldfrith as king of Northumbria, and Aldhelm's fosterage on Iona is reflected in aspects of his later literary activity. His period with Theodore and Hadrian (after 670) is illuminated by his familiarity with texts known to have been studied at Canterbury, and the length of Aldhelm's period of study there is extended by reconsideration of the date of his appointment as abbot of Malmesbury. Evidence also suggests that, while abbot, Aldhelm accompanied the West Saxon king Ceadwalla to Rome (688), and made a careful study of Latin inscriptions while there. An Appendix supplies a revised chronology of the composition of Aldhelm's Latin writings.
An abbot, an archbishop, and the viking raids of 1006–7 and 1009–12
Authors: Keynes Simon
Published: February 2009

After a period of sustained viking pressure, from 991 to 1005, the English had to endure two major raids in quick succession: the attack by ‘the great fleet’ in 1006–7, and the attack by ‘the immense raiding army’, also known as ‘Thorkell's army’, in 1009–12. This article reviews the impact of these raids on the English people, as reflected in the writings of Ælfric, abbot of Eynsham, and Wulfstan, archbishop of York, with reference at the same time to Æthelred's programme of prayer (VII Æthelred), devised by the king and his councillors in 1009, to the Agnus Dei coinage, and to the appearance of distinctive chrismons in charters. It is also suggested that Wulfstan's Sermo ad Anglos originated during these tumultuous years.
Attempted sounds are sometimes not: an expanded view of phonological selection and avoidance
Authors: Schwartz Richard G. , Leonard Laurence B. , Loeb Diane M. Frome , Swanson Lori A.
Published: February 2009

Young children readily acquire new words with consonants and syllable structures already used accurately (IN words). They have more difficulty acquiring new words with consonants or syllable structures never before produced or attempted (OUT words). In the present study, we examined children's acquisition of a third type of word, containing consonants the children had attempted in the past but never produced accurately (ATTEMPTED words). IN, OUT and ATTEMPTED words and their object referents were presented to 11 young children in a series of play sessions. The children's production and comprehension of the words were then assessed. No comprehension differences among the three types of words were observed. However, ATTEMPTED words as well as OUT words were less likely to be acquired in production than IN words. Some revisions in models of child phonology are proposed to accommodate these findings.
Individual variation and its relevance to a theory of phonological acquisition
Authors: Goad Heather , Ingram David
Published: February 2009

Stoel-Gammon & Cooper (1984) have recently presented phonological analyses in this journal of three children acquiring English. Their general conclusion is that the three children are each following their own unique pattern of acquisition. This paper is a response to that conclusion. We first point out that such research needs to distinguish different possible causes of variation. We then go on to criticize the method of analysis they used, arguing that it disposes the results towards individual variation. Next, we present an alternative analysis, using a different methodology, and show that the children's patterns of acquisition are actually relatively similar. Lastly, we conclude that both their and our results provide evidence for early phonological processing in opposition to the biological model presented in Locke (1983).
Age-relation, reliability and grammatical validity of measures of utterance length
Authors: Rondal Jean A. , Ghiotto Martine , Bredart Serge , Bachelet Jean-François
Published: February 2009

This study evaluated the age-relationship, intra-sample reliability and grammatical validity of MLU-like measures of utterance length in the free speech of 21 normally developing children aged 1;8 to 2;8 with MLU between 1·05 and 3·06. Contrary to a previous study by Klee & Fitzgerald (1985). it was found that measures of utterance length hold a good relation with age, are reliable and predict grammatical development well in the age and MLU range considered. It is argued that there are identifiable points in the developmental evolution of MLU and MLU-like indices beyond which their reliability and validity have serious problems. Below these points, they constitute sound measures of syntactic development.
The role of the initial utterance in contingent query sequences: its influence on responses to requests for clarification
Authors: Furrow David , Lewis Sherry
Published: February 2009

Utterances for which clarification is requested have not always been considered an integral part of the ensuing contingent query sequence. To examine this issue, characteristics of children's utterances which were targeted for requests for clarification were examined to determine if they influence the nature of responses. Any relationship here would (a) establish the role of the initial utterance as part of the contingent query discourse unit, and (b) begin the documentation of that role. Twenty-six children (nine aged between two and three, eleven between three and four, and six between four and five) were videotaped in a one-hour free-play session. Twenty times during the session an experimenter signalled non-comprehension of a comprehensible utterance by asking ‘What?’. The queried utterances were categorized as serving one of three functions (interpersonal, child activity or environmental) and as occurring in one of three social contexts (eye contact, other social or private). Responses were classified as being either a no-response, repetition or revision. Results showed that social context interacted with response type: more no-responses and fewer repetitions occurred in the private relative to the eye-contact context. This interaction demonstrated that the initial utterance plays a role in response determination, and is therefore an important part of the contingent query sequence. Findings also indicated that response type changed with development.
Child characteristics and maternal speech
Authors: Smolak Linda
Published: February 2009

Infant temperament characteristics of activity level, task persistence and affect were measured in an eight-month longitudinal study of eight children. Discourse and pragmatic features of their mothers' speech, specifically total number of utterances and use of self-repetitions, directives and attention-getting devices, were also monitored. Pearson correlation analysis suggested complex interactions between maternal speech and infant temperament. In some cases a maternal speech pattern appears to maintain an infant temperament characteristic. In others, a child characteristic appears to maintain a maternal speech form. The results are used to argue that non-linguistic child behaviours may influence maternal speech and deserve further attention in investigations of the link between maternal speech and child-language development.
Types of linguistic knowledge: interpreting and producing compound nouns
Authors: Clark Eve V. , Berman Ruth A.
Published: February 2009

The present study examined the types of linguistic knowledge that affect children's ability to understand and produce novel compounds in Hebrew. Sixty children aged 3;0–9;0, and 12 adults, were asked to interpret and to produce novel Noun + Noun compounds. Their comprehension was in advance of their production. In comprehension, morphological form of head nouns had little effect: from age four, children did equally well on all the compound forms tested; they identified head nouns and also possible relations between heads and their modifiers. In production, though, knowledge of morphological form was crucial. The fewer the changes children had to make in the forms of head nouns, the earlier they mastered that compound pattern. Finally, children who produced novel compounds correctly were also able to interpret novel compounds, but not vice versa.
How to make young children produce cleft sentences
Authors: Hupet Michel , Tilmant Brigitte
Published: February 2009

The present study focuses on the effects of contextual demands on the selection of a particular syntactic device, in asking whether French-speaking children from 4 to 10 years old will spontaneously produceit-cleft sentences if there is a functional necessity arising from the context. Taking into account recent studies that have specified the discourse function(s) served by this marked sentence form, it was hypothesized that the cleft formulation would be more likely than its uncleft counterpart whenever the child's intention was to contrast their own belief or knowledge with that of their addressee. The study showed this to be the case when the matter of the disagreement concerned the agent of an action: that situation elicited an overwhelming majority (from 80% to 97%) of cleft constructions, even from the youngest children. On the other hand, when the matter of the disagreement concerned the patient, there were only a few cleft constructions, even with the oldest children; contrastive stress on the object constituent was the predominant device employed for marking information in that situation. The high proportion of clefts in the Agent condition, and the high proportion of stressed object constituents in the Patient condition, both differ from previously reported data. These differences are discussed with reference to differences in task requirements and to differences between the prosodie constraints of French and English.
The linguistic marking of agentivity and control in child language
Authors: Budwig Nancy
Published: February 2009

The present study examines the relationship between linguistic forms and the functions they serve in children's early talk about agentivity and control. The spontaneous linguistic productions of six children ranging between 1;8 and 2;8 served as the data base. Preliminary analyses of who the children referred to and what forms were used in subject position suggest that the children could be divided into two groups. Three children primarily referred to Self and relied on multiple Self reference forms in subject position, while the other children referred to both Self and Other and primarily used the Self reference form, I. A functional analysis was carried out to examine whether the seemingly interchangeable use of Self reference forms could be related to semantic and pragmatic patterns. The findings indicate that at a time before they regularly refer to others, the children systematically employed different Self reference forms to mark distinct perspectives on agency.
Form and function in the acquisition of Korean wh-questions
Authors: Clancy Patricia M.
Published: February 2009

In this paper the order in which wh-questions are acquired in the production and comprehension of two Korean children, aged 1;8–2;8 and 1;10–2; 10, is analysed and compared with the available crosslinguistic data. Consistencies in acquisition order are hypothesized to be based on universals of cognitive development, which constrain the comprehension and production of wh-forms and influence the order in which mothers introduce them, and on functionally based similarities in the input of form/function pairs across children and languages. Discrepancies in acquisition order are attributed to differences in interactive style across caregivers and children, leading to different input frequencies of particular forms and individual children's selection of different forms for use.
How children understand idioms in discourse
Authors: Cacciari Cristina , Levorato Maria Chiara
Published: February 2009

Some studies have shown that children tend to interpret figurative language literally. Our hypothesis is that they can reach an idiomatic competence if idioms are presented within a rich informational environment allowing children to grasp their figurative sense. First and third graders were presented with narratives biased both to the figurative meaning of idioms (experiment 1) and to the literal meaning (experiment 2) and then given a comprehension task. Experiment 3 was designed to investigate children's production of idioms as compared to the comprehension abilities explored in experiments 1 and 2. Results show that informative contexts can improve children's ability to perceive idiomatic meanings even at the age of seven; and that children are less able to produce idioms than to comprehend them. Generally results emphasize that children seem able to perceive that language can be both figurative and literal.
A cross-language study of prosodic modifications in mothers' and fathers' speech to preverbal infants
Authors: Fernald Anne , Taeschner Traute , Dunn Judy , Papousek Mechthild , de Boysson-Bardies Bénédicte , Fukui Ikuko
Published: February 2009

This study compares the prosodie modifications in mothers' and fathers' speech to preverbal infants in French, Italian, German, Japanese, British English, and American English. At every stage of data collection and analysis, standardized procedures were used to enhance the comparability across data sets that is essential for valid cross-language comparison of the prosodie features of parental speech. In each of the six language groups, five mothers and five fathers were recorded in semi-structured home observations while speaking to their infant aged 0; 10–1;2 and to an adult. Speech samples were instrumentally analysed to measure seven prosodic parameters: mean fundamental frequency (f0), f0-minimum, f0-maximum, f0-range, f0-variability, utterance duration, and pause duration. Results showed cross-language consistency in the patterns of prosodic modification used in parental speech to infants. Across languages, both mothers and fathers used higher mean-f0, f0-minimum, and f0-maximum, greater f0-variability, shorter utterances, and longer pauses in infant-directed speech than in adult-directed speech. Mothers, but not fathers, used a wider f0-range in speech to infants. American English parents showed the most extreme prosodic modifications, differing from the other language groups in the extent of intonational exaggeration in Speech to infants. These results reveal common patterns in caretaker's use of intonation across languages, which may function developmentally to regulate infant arousal and attention, to communicate affect, and to facilitate speech perception and language comprehension. In addition to providing evidence for possibly universal prosodic features of speech to infants, these results suggest that language-specific variations are also important, and that the findings of the numerous studies of early language input based on American English are not necessarily generalisable to other cultures.
The transition from optional to required subjects
Authors: O'Grady William , Peters Ann M. , Masterson Deborah
Published: February 2009

We propose (contra Hyams, 1986) that the optional subject phenomenon in early child language arises because children have not yet acquired the morphological elements (primarily modals and tense) necessary to distinguish Subject-Taking (ST) verbs (e.g. finite verbs) from their non-Subject-Taking (NST) counterparts (e.g. infinitives). Unaware of this distinction, children are able only to observe that verbs sometimes occur with subjects and sometimes without. We show that our proposal makes a number of developmental predictions which we then test with the help of longitudinal data from three children. We conclude that: (i) There is no systematic morphological distinction between ST and NST verbs during the optional subject stage (OSS). (2) The emergence of the distinction between ST and NST verbs is gradual rather than sudden. (3) There is variation from child to child in terms of which morphologically-defined subclass of verbs is first recognized as subject-taking. (4) There is no link between the emergence of modals or contracted copulas and the end of the OSS.
Limits on negative information in language input
Authors: Morgan James L. , Travis Lisa L.
Published: February 2009

Hirsh-Pasek, Treiman & Schneiderman (1984).and Demetras, Post & Snow (1986).have recently suggested that certain types of parental repetitions and clarification questions may provide children with subtle cues to their grammatical errors. We further investigated this possibility by examining parental responses to inflectional over-regularizations and wh-question auxiliary-verb omission errors in the sets of transcripts from Adam, Eve and Sarah (Brown 1973). These errors were chosen because they are exemplars of overgeneralization, the type of mistake for which negative information is, in theory, most critically needed. Expansions and Clarification Questions occurred more often following ill-formed utterances in Adam's and Eve's input, but not in Sarah's. However, these corrective responses formed only a small proportion of all adult responses following Adam's and Eve's grammatical errors. Moreover, corrective responses appear to drop out of children's input while they continue to make overgeneralization errors. Whereas negative feedback may occasionally be available, in the light of these findings the contention that language input generally incorporates negative information appears to be unfounded.
Patterns of object–name extension in production
Authors: Chapman Kathy L. , Mervis Carolyn B.
Published: February 2009

The evolution of young children's categories, as measured by category name production, was studied. The focus was on categories whose names initially were overextended. Four children (initially aged 1; 1 to 1; 3) were visited at home twice a week over a four- to six-month period, until they were approximately 1;7. The play sessions included eli-citations of the names of specially chosen objects. Results indicated that, as predicted, four sequences of category evolution were found, formed by the intersection of two factors: overlap vs. mutual exclusivity and first re-assignment separate vs. first re-assignment joint. As expected, most sequences involved initial overlap, and the choice of first reassignment option varied as a function of the relationship (hierarchical or non-hierarchical) between the initial child-basic category and the new category.
Contextual information and temporal terms
Authors: Gorrell Paul , Crain Stephen , Fodor Janet Dean
Published: February 2009

We report an experiment designed to identify how contextual information can influence children's performance on an experimental task involving temporal terms. Grain (1982) reported improved performance on a comprehension task when subjects were provided with contextual information, and he suggested that the improvement was due to satisfaction of presuppositions. However, this contextual information might have served to simplify task demands by providing prior information concerning an important aspect of the task. The present study distinguishes these factors by incorporating contextual information into the subordinate clause of the test sentences in a comprehension experiment (to satisfy presupposions) or into the main clause (to provide comparable prior information without satisfying presuppositions). We conclude that contextual information results in a significant improvement only when such information can be used to satisfy presuppositions.