bluuebunny/crossref_metadata_2025_split huggingface dataset:
Developmental increase of asynchronic glutamate release from hippocampal synapses in mutant taiep rat
Authors: Fuenzalida Marco , Aliaga Esteban , Olivares Virginia , Roncagliolo Manuel , Bonansco Christian 
Published: February 2009

AbstractDuring development, regulation of the strength of synaptic transmission plays a central role in the formation of mammalian brain circuitries. In taiep rat, a neurological mutant with severe reactive astrogliosis and demyelination, we have described alterations in the synaptic transmission in central neurons, characterized by asynchronous excitatory postsynaptic currents (ASYNEPSCs), because of delayed neurotransmitter release. This hippocampal synaptic dysfunction has been described in juvenile mutants, concomitantly with the appearance of their main glial alterations. However, it is unknown whether this abnormal synaptic activity is correlated with some alterations of synaptic maturation during the postnatal development. Using intracellular electrophysiological recordings and immunohistochemistry assays, we studied the maturation of CA3‐CA1 synapses in taiep rats. In taiep, the number of ASYNEPSCs evoked by conventional stimulation of Schaffer collaterals increases with age (P7–P30) and can be evoked by stimulation of single fiber. The amplitude and frequency of spontaneous EPSC (sEPSC) increased during the postnatal development in both control and taiep rats. However, in taiep, the increase of sEPSC frequency was significantly higher than in the control rats. The frequency of miniature EPSC (mEPSC) increased over the studied age range, without differences between taiep and control rats. In both control and taiep groups, the synaptophysin immunostaining (SYP‐IR) in the stratum radiatum of CA1 region was significantly lower in the juvenile (P30) than in the neonatal (P10) rats, suggesting that synaptic pruning is normally occurring in taiep, even when SYP‐IR was higher in taiep than control in both ages studied. These results suggest that, in taiep mutants, the asynchronic transmission is due to a dysfunction in the glutamate release mechanisms that progressively increases during development, which is not attributable to the existence of aberrant synaptic contacts. Synapse 63:502–509, 2009. © 2009 Wiley‐Liss, Inc.
Transperineal ultrasound imaging in prolonged second stage of labor with occipitoanterior presenting fetuses: how well does the ‘angle of progression’ predict the mode of delivery?
Authors: Kalache K. D. , Dückelmann A. M. , Michaelis S. A. M. , Lange J. , Cichon G. , Dudenhausen J. W. 
Published: February 2009

AbstractObjectivesTo compare the angle of progression on transperineal ultrasound imaging between different modes of delivery in prolonged second stage of labor with occipitoanterior fetal position.MethodsWe prospectively evaluated 41 women at term (≥ 37 weeks) with failure to progress in the second stage of labor. Only cases with occipitoanterior fetal position were included in the final analysis. These cases were classified into three groups: Cesarean section for failure to progress, vacuum extraction for failure to progress, and spontaneous delivery following prolonged second stage of labor. Transperineal ultrasound examination was performed just before digital examination and subsequent delivery. The angle between a line placed through the midline of the pubic symphysis and a line running from the inferior apex of the symphysis tangentially to the fetal skull (the so‐called ‘angle of progression’) was measured offline by an observer blinded to the mode of delivery.ResultsThere were 26 cases with occipitoanterior fetal position (Cesarean section, n = 5; vacuum extraction, n = 16; spontaneous delivery, n = 5). Logistic regression analysis showed a strong relationship between the angle of progression and the need for Cesarean delivery (R2 measure of fit = 55%, likelihood ratio chi‐square P < 0.0001). When the angle of progression was 120°, the fitted probability of either an easy and successful vacuum extraction or spontaneous vaginal delivery was 90%.ConclusionsThis is the first report to document a strong relationship between an objective ultrasound marker (angle of progression) and the mode of delivery following prolonged second stage of labor with occipitoanterior fetal position. A predictive model using this parameter would allow better decision making regarding operative delivery for obstructed labor. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Three‐dimensional endoanal ultrasonography: intraobserver and interobserver agreement using scoring systems for classification of anal sphincter defects
Authors: Norderval S. , Dehli T. , Vonen B. 
Published: February 2009

AbstractObjectivesTo determine the degree of intraobserver and interobserver agreement for an experienced and an inexperienced sonologist using two scoring systems for ultrasonographic assessment of anal sphincter defects.MethodsThe study sample comprised the datasets of all women aged between 20 and 40 years who had attended our outpatient clinic and undergone a complete three‐dimensional (3D) endoanal ultrasound (EAUS) examination in the period from January 2003 to December 2005. The EAUS datasets were assessed twice independently by two sonologists: one with experience of > 400 3D EAUS assessments and one inexperienced sonologist who had performed approximately 50 assessments before the study. Cases with intraobserver disagreement were resolved by a third (final) assessment. The final assessment from each observer was used to determine the degree of interobserver agreement. Sphincter defects were classified according to our EAUS defect score and the Starck score.ResultsEAUS datasets of 55 women were included. Based on first vs. second assessments, intraobserver agreement for the experienced sonologist was good for our EAUS defect score (weighted kappa, 0.75) and the Starck score (weighted kappa, 0.73). Intraobserver agreement for the inexperienced sonologist was moderate for our EAUS defect score (weighted kappa, 0.58) and good for the Starck score (weighted kappa, 0.62). Interobserver agreement was good for both our EAUS defect score (weighted kappa, 0.65) and the Starck score (weighted kappa, 0.74).ConclusionsIntraobserver and interobserver agreement was acceptable for both scoring systems. The experienced sonologist obtained a higher degree of intraobserver agreement than did the inexperienced sonologist. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
On the singularities of constrained tensegrity systems – application to a modified T3 model
Authors: Pirentis A.P. , Markatis S. , Lazopoulos K.A. , Lazopoulos A.K. 
Published: February 2009

AbstractSingularity theory is applied for the study of constrained tensegrity systems. Previous studies have already been performed on non‐constrained systems; however, the present one allows for general non‐symmetric equilibrium configurations. A modified T3 tensegrity model comprising seven rigid bars, three elastic cables and one rotational spring is considered. The stability of this model is examined performing singularity theory for deformations under conservative quasistatic loading. Critical conditions for branching of the equilibrium paths are defined and their post‐critical behavior is discussed. Classification of the simple and compound singularities of the total potential energy function is effected. The theory is implemented into the fold catastrophe of the asymmetric configuration of the modified T3 tensegrity model and an elliptic umbilic singularity for the case of compound branching. It is pointed out that singularity studies with constraints demand a quite different mathematical approach than those without constraints.
Vektorfeldalgebren, Gruppenaktionen und das Keplerproblem
Authors: Hamburger C. 
Published: February 2009

AbstractWe supply an analytic proof of the theorem of Palais about the existence of a Lie group action on a compact manifold M with a Lie algebra 𝔳 of vector fields. Every compact connected integral manifold N of 𝔳 is then diffeomorphic to a homogeneous manifold. In the special case of a Lie algebra of Hamiltonian vector fields, the group action consists of symplectic diffeomorphisms. Applications are the non‐commutative version of the Cauchy initial value problem for Hamilton‐Jacobi systems and of Liouville's theorem. As examples with non‐compact M, we determine group actions for the harmonic oscillator and for Kepler's problem.
Study of Materials Deformation in Nanometric Cutting by Large-scale Molecular Dynamics Simulations
Authors: Pei QX , Lu C , Lee HP , Zhang YW 
Published: February 2009

Abstract
Nanometric cutting involves materials removal and deformation evolution in the surface at nanometer scale. At this length scale, atomistic simulation is a very useful tool to study the cutting process. In this study, large-scale molecular dynamics (MD) simulations with the model size up to 10 millions atoms have been performed to study three-dimensional nanometric cutting of copper. The EAM potential and Morse potential are used, respectively, to compute the interaction between workpiece atoms and the interactions between workpiece atoms and tool atoms. The material behavior, surface and subsurface deformation, dislocation movement, and cutting forces during the cutting processes are studied. We show that the MD simulation model of nanometric cutting has to be large enough to eliminate the boundary effect. Moreover, the cutting speed and the cutting depth have to be considered in determining a suitable model size for the MD simulations. We have observed that the nanometric cutting process is accompanied with complex material deformation, dislocation formation, and movement. We find that as the cutting depth decreases, the tangential cutting force decreases faster than the normal cutting force. The simulation results reveal that as the cutting depth decreases, the specific cutting force increases, i.e., “size effect” exists in nanometric cutting.
The neural basis of auditory temporal discrimination in girls with fragile X syndrome
Authors: Hall Scott S. , Walter Elizabeth , Sherman Elena , Hoeft Fumiko , Reiss Allan L. 
Published: February 2009

Abstract
Fragile X syndrome (FXS) is a common genetic disorder in which temporal processing may be impaired. To our knowledge however, no studies have examined the neural basis of temporal discrimination in individuals with FXS using functional magnetic resonance imaging (fMRI). Ten girls with fragile X syndrome and ten developmental age-matched typically developing controls performed an auditory temporal discrimination task in a 3T scanner. Girls with FXS showed significantly greater brain activation in a left-lateralized network, comprising left medial frontal gyrus, left superior and middle temporal gyrus, left cerebellum, and left brainstem (pons), when compared to a developmental age-matched typically developing group of subjects who had similar in-scanner task performance. There were no regions that showed significantly greater brain activation in the control group compared to individuals with FXS. These data indicate that networks of brain regions involved in auditory temporal processing may be dysfunctional in FXS. In particular, it is possible that girls with FXS employ left hemispheric resources to overcompensate for relative right hemispheric dysfunction.
Continuous Methanolysis of Palm Oil Using a Liquid–Liquid Film Reactor
Authors: Narváez P. C. , Sánchez F. J. , Godoy‐Silva R. D. 
Published: February 2009

AbstractA system for the continuous methanolysis of palm oil using a liquid–liquid film reactor (LLFR) was developed and characterized. This reactor is a co‐current, constant diameter (0.01 m), custom‐made packed column where the mass transfer area between the partially miscible methanol‐rich and vegetable oil‐rich phases is created in a non‐dispersive way, without the intervention of mechanical stirrers or ultrasound devices. An increase in contact area between phases enhances reaction rate while the absence of small, dispersed droplets of one phase into the other diminishes the settling time at the end of the reaction. In this study variations on the concentration of catalyst (sodium hydroxide), flow rate of palm oil and normalized length of the reactor (L/Lmax) were explored, keeping constant both the methanol to oil molar ratio and the temperature of the reaction (6:1 and 60 °C). The best experimental results with a reactor of 1.26 m (L/Lmax = 1.0) showed a conversion of palm oil of 97.5% and a yield of methyl esters of 92.2% of the theoretical yield, when the mass flow rate and the residence time of the palm oil were 9.0 g min−1 and 5.0 min, respectively. To determine the mean residence time and the degree of axial mixing in the reactor, a residence time distribution (RTD) study was performed using a step‐function input. The dispersion model appears to fit well the RTD experimental data.
Effect of Alkyl Chain Unsaturation on Methyl Ester Thermo‐Oxidative Decomposition and Residue Formation
Authors: Pillar Rachel , Ginic‐Markovic Milena , Clarke Stephen , Matisons Janis 
Published: February 2009

AbstractThe formation of persistent residues by esters used in sheet metal‐working lubricant formulations interferes with metal surface cleanliness and impairs the integrity of subsequent surface coatings. Understanding the thermal decomposition and residue formation properties of esters is therefore crucial to minimising residue formation during furnace‐based cleaning and will aid in the improvement of coated metal products such as galvanised steel. The thermo‐oxidative decomposition profiles of four different methyl esters were studied by Thermogravimetric Analysis (TGA) and Pressure Differential Scanning Calorimetry (PDSC). Chemical characterisation of residues remaining at different stages during the thermo‐oxidative decomposition process was achieved by infrared spectroscopic analysis of TGA residue samples. Relationships between ester alkyl chain unsaturation levels and the amount/chemical nature of residue present at high temperature (500 °C) were assessed. In the presence of oxygen, polyunsaturated esters decomposed to leave significantly greater amounts of thermally‐stable residue, comprising of metal carboxylate and non‐volatile oxygenated compounds, than more saturated esters. Given that the formation of analogous residues by more complex esters used in sheet metal‐working lubricants may give rise to metal surface coating defects, the results of this study suggest that polyunsaturated esters should be avoided in lubricant formulations where preventing residue formation is of paramount importance.
An algorithmic model for constructing a linkage and linkage disequilibrium map in outcrossing plant populations
Authors: LI JIAHAN , LI QIN , HOU WEI , HAN KUN , LI YAO , WU SONG , LI YANCHUN , WU RONGLING 
Published: February 2009

SummaryA linkage–linkage disequilibrium map that describes the pattern and extent of linkage dis-equilibrium (LD) decay with genomic distance has now emerged as a viable tool to unravel the genetic structure of population differentiation and fine-map genes for complex traits. The prerequisite for constructing such a map is the simultaneous estimation of the linkage and LD between different loci. Here, we develop a computational algorithm for simultaneously estimating the recombination fraction and LD in a natural outcrossing population with multilocus marker data, which are often estimated separately in most molecular genetic studies. The algorithm is founded on a commonly used progeny test with open-pollinated offspring sampled from a natural population. The information about LD is reflected in the co-segregation of alleles at different loci among parents in the population. Open mating of parents will reveal the genetic linkage of alleles during meiosis. The algorithm was constructed within the polynomial-based mixture framework and implemented with the Expectation–Maximization (EM) algorithm. The by-product of the derivation of this algorithm is the estimation of outcrossing rate, a parameter useful to explore the genetic diversity of the population. We performed computer simulation to investigate the influences of different sampling strategies and different values of parameters on parameter estimation. By providing a number of testable hypotheses about population genetic parameters, this algorithmic model will open a broad gateway to understand the genetic structure and dynamics of an outcrossing population under natural selection.
Mapping QTL for multiple traits using Bayesian statistics
Authors: XU CHENWU , WANG XUEFENG , LI ZHIKANG , XU SHIZHONG 
Published: February 2009

SummaryThe value of a new crop species is usually judged by the overall performance of multiple traits. Therefore, in most quantitative trait locus (QTL) mapping experiments, researchers tend to collect phenotypic records for multiple traits. Some traits may vary continuously and others may vary in a discrete fashion. Although mapping QTLs jointly for multiple traits is more efficient than mapping QTLs separately for individual traits, the latter is still commonly practised in QTL mapping. This is primarily due to the lack of efficient statistical methods and computer software packages to implement the methods. Mapping multiple QTLs simultaneously in a single multivariate model has not been available, especially when categorical traits are involved. In the present study, we developed a Bayesian method to map QTLs of the entire genome for multiple traits with continuous, discrete or both types of phenotypic distribution. Instead of using the reversible jump Markov chain Monte Carlo (MCMC) for model selection, we adopt a parameter shrinkage approach to estimate the genetic effects of all marker intervals. We demonstrate the method by analysing a set of simulated data with both continuous and discrete traits. We also apply the method to mapping QTLs responsible for multiple disease resistances to the blast fungus of rice. A computer program written in SAS/IML that implements the method is freely available, on request, to academic researchers.
Increased accuracy of artificial selection by using the realized relationship matrix
Authors: HAYES B. J. , VISSCHER P. M. , GODDARD M. E. 
Published: February 2009

SummaryDense marker genotypes allow the construction of the realized relationship matrix between individuals, with elements the realized proportion of the genome that is identical by descent (IBD) between pairs of individuals. In this paper, we demonstrate that by replacing the average relationship matrix derived from pedigree with the realized relationship matrix in best linear unbiased prediction (BLUP) of breeding values, the accuracy of the breeding values can be substantially increased, especially for individuals with no phenotype of their own. We further demonstrate that this method of predicting breeding values is exactly equivalent to the genomic selection methodology where the effects of quantitative trait loci (QTLs) contributing to variation in the trait are assumed to be normally distributed. The accuracy of breeding values predicted using the realized relationship matrix in the BLUP equations can be deterministically predicted for known family relationships, for example half sibs. The deterministic method uses the effective number of independently segregating loci controlling the phenotype that depends on the type of family relationship and the length of the genome. The accuracy of predicted breeding values depends on this number of effective loci, the family relationship and the number of phenotypic records. The deterministic prediction demonstrates that the accuracy of breeding values can approach unity if enough relatives are genotyped and phenotyped. For example, when 1000 full sibs per family were genotyped and phenotyped, and the heritability of the trait was 0·5, the reliability of predicted genomic breeding values (GEBVs) for individuals in the same full sib family without phenotypes was 0·82. These results were verified by simulation. A deterministic prediction was also derived for random mating populations, where the effective population size is the key parameter determining the effective number of independently segregating loci. If the effective population size is large, a very large number of individuals must be genotyped and phenotyped in order to accurately predict breeding values for unphenotyped individuals from the same population. If the heritability of the trait is 0·3, andNe=1000, approximately 5750 individuals with genotypes and phenotypes are required in order to predict GEBVs of un-phenotyped individuals in the same population with an accuracy of 0·7.
The Name ‘Merovingian’ and the Dating of Beowulf
Authors: Goffart Walter 
Published: February 2009

AbstractReviving an argument of 1849, Tom Shippey has lately maintained that the dynasty name ‘Merovingian’ in Beowulf furnishes a firm criterion for attributing an early date to the poem. He contends, using an electronic database, that a deliberate damnatio memoriae caused the name ‘Merovingian’ to fade soon after the dynasty was deposed (751); its occurrence is therefore a terminus ad quem. This article shows that the Carolingians took pains to affirm continuity with their predecessors. The first Frankish dynasty was not condemned to oblivion. Its name was well known in the ninth century and occurs repeatedly in later historiography.
Poisoned places: the Avernian tradition in Old English poetry
Authors: Anlezark Daniel 
Published: February 2009

AbstractScholars have long disputed whether or not Beowulf reflects the influence of Classical Latin literature. This essay examines the motif of the ‘poisoned place’ present in a range of texts known to the Anglo-Saxons, most famously represented by Avernus in the Aeneid. While Grendel's mere presents the best-known poisonous locale in Old English poetry, another is found in the dense and enigmatic poem Solomon and Saturn II. The relationship between these poems is discussed beside a consideration of the possibility that their use of the ‘Avernian tradition’ points to the influence of Latin epic on their Anglo-Saxon authors.
Ethnographic interpretations of parent-child discourse in Huli
Authors: Goldman Laurence Richard 
Published: February 2009

ABSTRACTThis paper seeks to account for a culturally patterned set of analogic renamings found in Huli baby talk, nursery rhymes and children's verbal games. These socialization activities evidence a marked concern with body motifs and appellations. In accordance with ethnographic paradigms of explanation, the frame of reference is broadened to include consideration of inter-adult behaviour involving ‘talk about the body’ to assess what is being learnt from such interactions as well as what communicative intents are encoded. The argument is developed that in addition to the significance of these play routines in sensitizing the child to cultural rules about speaking, these ludic forms also appear implicated in both an evolutionary and logico-operational sense in the conventional anatomical nomenclature.