bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuromuscular control of lumbar instability following static work of various loads
Authors: Le Brook , Davidson Bradley , Solomonow Deborah , Zhou Bing He , Lu Yun , Patel Vikas , Solomonow Moshe
Published: December 2008

Neuromuscular control of lumbar stability following exposure to prolonged static work, under low and high loads, was assessed in the in vivo feline model. Six sessions of 10 min work at 20N with 10 min between rest was compared to a group subjected to the same protocol but carrying high loads of 60N. Displacement and tension developed in the spine at the instant the multifidus muscles applied stabilizing contractions, and their amplitudes were obtained from their electromyogram (EMG). Significant (P < 0.001) laxity developed in the various viscoelastic tissues of the lumbar spine that did not recover during and up to 7 h of rest postwork. Simultaneously, there was a significant (P < 0.001) decrease in muscular activity in the 3–4 h immediately postwork under low load but only during the first hour in the high load group. After that period the musculature compensated for the laxity of the viscoelastic tissues by a significant (P < 0.001) increase in activity in the high‐load group and a nonsignificant increase in the low group. It was concluded that during 1–3 h immediately poststatic work a significant decrease in the stabilizing function of viscoelastic tissues together with a significant decrease in muscular activity is present, and they render the spine unstable and exposed to high risk of injury. Performance of prolonged static work under low loads, while not harmful during the work, cannot be designated as a “no‐risk” condition, as it may result in injury postwork. Muscle Nerve 39: 71–82, 2009
Proton MRS of the breast in the clinical setting
Authors: Mountford Carolyn , Ramadan Saadallah , Stanwell Peter , Malycha Peter
Published: December 2008

Information for determining whether a primary breast lesion is invasive and its receptor status and grade can be obtained before surgery by performing proton MRS on a fine‐needle aspiration biopsy (FNAB) specimen and analyzing the MRS information by a pattern recognition method. Two‐dimensional MRS, on either specimens or cells, allows the unambiguous assignment of most resonances. When correlated with the spectral regions selected by the pattern recognition method, there are strong indications for the biochemical markers responsible for prognostic information of invasive capacity and metastatic spread. Spectral assignments and biological correlations can be made using cell models. In vivo MRS can distinguish invasive from benign lesions. This pathological distinction can be made from the presence of resonances at discrete frequencies. To achieve this level of spectral resolution and signal‐to‐noise ratio, there are stringent requirements when acquiring and processing the data. The challenge now is to implement two‐dimensional MRS in vivo. Until this is realized, the combination of in vivo MR, for diagnosis and spatial location, and MRS, for image‐guided biopsy to provide information on tumor spread, promises to provide a higher level of preoperative diagnosis than previously achieved. Copyright © 2008 John Wiley & Sons, Ltd.
Investigation of breast cancer using two‐dimensional MRS
Authors: Thomas M. Albert , Lipnick Scott , Velan S. Sendhil , Liu Xiaoyu , Banakar Shida , Binesh Nader , Ramadan Saadallah , Ambrosio Art , Raylman Raymond R. , Sayre James , DeBruhl Nanette , Bassett Lawrence
Published: December 2008

Proton (1H) MRS enables non‐invasive biochemical assay with the potential to characterize malignant, benign and healthy breast tissues. In vitro studies using perchloric acid extracts and ex vivo magic angle spinning spectroscopy of intact biopsy tissues have been used to identify detectable metabolic alterations in breast cancer. The challenges of 1H MRS in vivo include low sensitivity and significant overlap of resonances due to limited chemical shift dispersion and significant inhomogeneous broadening at most clinical magnetic field strengths. Improvement in spectral resolution can be achieved in vivo and in vitro by recording the MR spectra spread over more than one dimension, thus facilitating unambiguous assignment of metabolite and lipid resonances in breast cancer. This article reviews the recent progress with two‐dimensional MRS of breast cancer in vitro, ex vivo and in vivo. The discussion includes unambiguous detection of saturated and unsaturated fatty acids, as well as choline‐containing groups such as free choline, phosphocholine, glycerophosphocholine and ethanolamines using two‐dimensional MRS. In addition, characterization of invasive ductal carcinomas and healthy fatty/glandular breast tissues non‐invasively using the classification and regression tree (CART) analysis of two‐dimensional MRS data is reviewed. Copyright © 2008 John Wiley & Sons, Ltd.
Concurrently coupled atomistic and XFEM models for dislocations and cracks
Authors: Gracie Robert , Belytschko Ted
Published: December 2008

A method for the modeling of dislocations and cracks by atomistic/continuum models is described. The methodology combines the extended finite element method with the bridging domain method (BDM). The former is used to model crack surfaces and slip planes in the continuum, whereas the BDM is used to link the atomistic models with the continuum. The BDM is an overlapping domain decomposition method in which the atomistic and continuum energies are blended so that their contributions decay to their boundaries on the overlapping subdomain. Compatibility between the continua and atomistic domains is enforced by a continuous Lagrange multiplier field. The methodology allows for simulations with atomistic resolution near crack fronts and dislocation cores while retaining a continuum model in the remaining part of the domain and so a large reduction in the number of atoms is possible. It is applied to the modeling of cracks and dislocations in graphene sheets. Energies and energy distributions compare very well with direct numerical simulations by strictly atomistic models. Copyright © 2008 John Wiley & Sons, Ltd.
On methods for stabilizing constraints over enriched interfaces in elasticity
Authors: Sanders Jessica D. , Dolbow John E. , Laursen Tod A.
Published: December 2008

Enriched finite element approaches such as the extended finite element method provide a framework for constructing approximations to solutions of non‐smooth problems. Internal features, such as boundaries, are represented in such methods by using discontinuous enrichment of the standard finite element basis. Within such frameworks, however, imposition of interface constraints and/or constitutive relations can cause unexpected difficulties, depending upon how relevant fields are interpolated on un‐gridded interfaces. This work address the stabilized treatment of constraints in an enriched finite element context.

Both the Lagrange multiplier and penalty enforcement of tied constraints for an arbitrary boundary represented in an enriched finite element context can lead to instabilities and artificial oscillations in the traction fields. We demonstrate two alternative variational methods that can be used to enforce the constraints in a stable manner. In a ‘bubble‐stabilized approach,’ fine‐scale degrees of freedom are added over elements supporting the interface. The variational form can be shown to have a similar form to a second approach we consider, Nitsche's method, with the exception that the stabilization terms follow directly from the bubble functions.

In this work, we examine alternative variational methods for enforcing a tied constraint on an enriched interface in the context of two‐dimensional elasticity. We examine several benchmark problems in elasticity, and show that only Nitsche's method and the bubble‐stabilization approach produce stable traction fields over internal boundaries. We also demonstrate a novel difference between the penalty method and Nitsche's method in that the latter passes the patch test exactly, regardless of the stabilization parameter's magnitude. Results for more complicated geometries and triple interface junctions are also presented. Copyright © 2008 John Wiley & Sons, Ltd.
Comparative study of paclitaxel physically encapsulated in and chemically conjugated with PEG‐PLA
Authors: Xu Xiaoyi , Zhang Xuefei , Wang Xiuhong , Li Yuxin , Jing Xiabin
Published: December 2008

Paclitaxel‐loaded poly(ethylene glycol)‐b‐poly(l‐lactide (LA)) (PEG‐PLA) micelles were prepared by two methods. One is physical encapsulation of paclitaxel in micelles composed of a PEG‐PLA block copolymer and the other is based on a PEG‐PLA–paclitaxel conjugate, abbreviated as “conjugate micelles”. Their physicochemical characteristics, e.g. critical micelle concentration (CMC), morphology, and micelle size distribution were then evaluated by means of fluorescence spectroscopy, scanning electron microscopy (SEM), and dynamic light scattering (DLS). The results show that the CMC of PEG‐PLA–paclitaxel and PEG‐PLA are 6.31 × 10−4 and 1.78 × 10−3 g L−1, respectively. Both micelles assume a spherical shape with comparable diameters and have unimodal size distribution. Moreover, invitro drug delivery behavior was studied by high performance liquid chromatography (HPLC). The antitumor activity of the paclitaxel‐loaded micelles against human liver cancer H7402 cells was evaluated by 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) method. The conjugate micelles show a lower burst release during the initial stage and higher accumulative release amount of paclitaxel after a period of time while the encapsulated ones behave in the opposite way. Both the paclitaxel‐loaded micelles showed comparable anticancer efficacy with the free drug. Copyright © 2008 John Wiley & Sons, Ltd.
Tribological properties of epoxy/polyurea composite
Authors: Hu Haixia , Yu Sirong , Wang Mingyu , Ma Jun , Liu Kaixin
Published: December 2008

The tribological behavior of epoxy/polyurea composite under dry friction was investigated. The worn surface morphologies of epoxy and epoxy/polyurea composite have been analyzed using scanning electron microscopy (SEM), and the functional group of epoxy and epoxy/polyurea composite before and after wear have been analyzed by a Fourier transform infrared spectrometer (FT‐IR). It has been found that epoxy terminal groups, which exist in an epoxy molecule, can react with the end group amine of the polyurea copolymer, generating more HO bonds, which enhances the deformation capacity. Polyurea particles are dispersed uniformly in epoxy matrix before wear, while plastic deformation and distorted domains occur on the worn surface of epoxy/polyurea composite. This indicates that the wear resistance of epoxy/polyurea composite was greatly improved by the addition of polyurea elastomer, which led to low frictional coefficients and wear mass losses. Copyright © 2008 John Wiley & Sons, Ltd.
A novel cyanate ester resin/microcapsules system
Authors: Yuan Li , Gu Aijuan , Liang Guozheng
Published: December 2008

Poly(urea‐formaldehyde) microcapsules filled with epoxy resins(MCEs) were applied to bisphenol A dicyanate ester (BADCy) resin to develop a novel BADCy/MCEs system. The effects of MCEs on the viscosity and the reactivity of BADCy were investigated. The mechanical properties and the hot water resistance of cured BADCy/MCEs systems were evaluated. The morphologies of the cured systems were characterized using a scanning electron microscope. The thermal property of cured systems was investigated using thermogravimetric analysis. The results indicate that MCEs may influence the reaction of BDACy. The proper addition of MCEs can significantly improve the mechanical property and the hot water resistance of cured BADCy resin. MCEs have a negative influence on the initial thermal decomposition temperature (Td) of cured BADCy resin. POLYM. COMPOS., 2010. © 2008 Society of Plastics Engineers.
Development of Nano‐TiO2 dye sensitised solar cells on high mobility transparent conducting oxide thin films
Authors: Bowers J. W. , Upadhyaya H. M. , Calnan S. , Hashimoto R. , Nakada T. , Tiwari A. N.
Published: December 2008

The optical transmission of dye‐sensitised solar cells (DSCs) can be tuned by altering the dye and/or particle size of the mesoporous TiO2 layers, to allow their application as the top device in tandem solar cells. To benefit from this semi‐transparency, parasitic optical losses by the transparent electrodes must be minimised. This work investigates the influence of using two different transparent conductors, namely, the high mobility material titanium doped indium oxide (ITiO) and fluorine doped tin oxide (FTO) as electrodes for semi‐transparent DSCs. The overall NIR transparency through the DSCs increased significantly as each FTO electrode was replaced by an ITiO electrode. This increase was from 20–45% in the 1300–700 nm wavelength range for fully FTO‐based cells, to about 60% for fully ITiO‐based cells, across the same spectrum. DSCs prepared on these electrodes exhibited short circuit currents ranging from 14·0–14·9 mA/cm2. The conversion efficiency of the cell with ITiO as both the front and rear electrodes was 5·8%, which though significant, was lower than the 8·2% attained by the cell using FTO electrodes, as a result of a lower fill factor. Improvements in the ITiO thermal stability and in the processing of the TiO2 interfacial layer are expected to improve the cell efficiency of such single DSC devices. The high current density and optical transparency of ITiO‐based DSCs make them an interesting option for tandem solar cells. Copyright © 2008 John Wiley & Sons, Ltd.
Chemistry of aryl N‐(2‐pyridyl) thionocarbamates in basic media
Authors: Silva Daniel , Norberto Fátima , Santos Susana , Hervés Pablo
Published: December 2008

Three aryl N‐pyridylthionocarbamates were synthesized by thioacylation of 2‐aminopyridine and 2‐methylaminopyridine with the respective chlorothionoformates. Their hydrolysis mechanism was studied in aqueous basic media. The aryl N‐(2‐pyridyl)thionocarbamates are considerably less reactive than their oxo analogues, the aryl N‐(2‐pyridyl) carbamates, especially the N‐monosubstituted ones (1a‐b). Absence of significant buffer catalysis, isolation of the product resulting from trapping of the unsaturated intermediate with piperidine and the entropy of activation observed for the hydrolysis of compound 1b clearly indicate an E1cB mechanism for the N‐monosubstituted aryl N‐(2‐pyridyl)thionocarbamates. The experimental data suggest that the N,N‐disubstituted substrate (2) undergoes basic hydrolysis by a general base catalysed BAC2 mechanism. Copyright © 2008 John Wiley & Sons, Ltd.
Solubility behavior of amphiphilic block and random copolymers based on 2‐ethyl‐2‐oxazoline and 2‐nonyl‐2‐oxazoline in binary water–ethanol mixtures
Authors: Lambermont‐Thijs Hanneke M. L. , Hoogenboom Richard , Fustin Charles‐André , Bomal‐D'Haese Cécile , Gohy Jean‐François , Schubert Ulrich S.
Published: December 2008

The solution properties of random and block copolymers based on 2‐ethyl‐2‐oxazoline (EtOx) and 2‐nonyl‐2‐oxazoline (NonOx) were investigated in binary solvent mixtures ranging from pure water to pure ethanol. The solubility phase diagrams for the random and block copolymers revealed solubility (after heating), insolubility, dispersions, micellization as well as lower critical solution temperature (LCST) and upper critical solution temperature behavior. The random and block copolymers containing over 60 mol % pNonOx were found to be solubilized in ethanol upon heating, whereas the dissolution temperature of the block copolymers was found to be much higher than for the random copolymers due to the higher extent of crystallinity. Furthermore, the block copolymer containing 10 mol % pNonOx exhibited a LCST in aqueous solution at 68.7 °C, whereas the LCST for the random copolymer was found to be only 20.8 °C based on the formation of hydrophobic microdomains in the block copolymer. The random copolymer displayed a small increase in LCST up to a solvent mixture of 9 wt % EtOH, whereas further increase of ethanol led to a decrease in LCST, which is probably due to the “water‐breaking” effect causing an increased attraction between ethanol and the hydrophobic part of the copolymer. In addition, the EtOx‐NonOx block copolymers revealed the formation of micelles and dynamic light scattering demonstrated that the micellar size is increasing with increasing the ethanol content due to the enhanced solubility of EtOx. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 515–522, 2009
Long‐lived layered silicates‐immobilized 2,6‐bis(imino)pyridyl iron (II) catalysts for hybrid polyethylene nanocomposites by in situ polymerization: Effect of aryl ligand and silicate modification
Authors: Leone Giuseppe , Bertini Fabio , Canetti Maurizio , Boggioni Laura , Conzatti Lucia , Tritto Incoronata
Published: December 2008

Heterogeneous‐layered silicate‐immobilized 2,6‐bis(imino)pyridyl iron (II) dichloride/MMAO catalysts, in which the active polymerization species are intercalated within sodium‐ and organomodified‐layered silicate galleries, were prepared for producing hybrid exfoliated polyethylene (PE) nanocomposites by means of in situ polymerization. The inorganic filler was first treated with modified‐methylaluminoxane (MMAO) to produce a supported cocatalyst: MMAO reacts with silicates replacing most of the organic surfactant, thus modifying the original crystallographic clay order. MMAO anchored to the nanoclay was able to activate polymerization iron complexes initiating the polymer growth directly from the filler lamellae interlayer. The polymerization mechanism taking place in between the montmorillonite lamellae separates the layers, thus promoting deagglomeration and effective clay dispersion. Transmission electron microscopy revealed that in situ polymerization by catalytically active iron complexes intercalated within the lower organomodified clay led to fine dispersion and high exfoliation extent. The intercalated clay catalysts displayed a longer polymerization life‐time and brought about ethylene polymerization more efficiently than analogous homogeneous systems. PEs having higher molecular masses were obtained. These benefits resulted to be dependent more on the filler nature than on the ligand environment around the iron metal center and the experimental synthetic route. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 548–564, 2009
Prediction of 3D metal binding sites from translated gene sequences based on remote‐homology templates
Authors: Levy Ronen , Edelman Marvin , Sobolev Vladimir
Published: December 2008

Database‐scale analysis was performed to determine whether structural models, based on remote homologues, are effective in predicting 3D transition metal binding sites in proteins directly from translated gene sequences. The extent by which side chain modeling alone reduces sensitivity and selectivity is shown to be <10%. Surprisingly, selectivity was not dependent on the level of sequence homology between template and target, or on the presence of a metal ion in the structural template. Applying a modification of the CHED algorithm (Babor et al., Proteins 2008;70:208–217) and machine learning filters, a selectivity of ∼90% was achieved for protein sequences using unrelated structural templates over a sequence identity range of 18–100%. Below ∼18% identity, the number of analyzable target‐template pairs and predictability of metal binding sites falls off sharply. A full third of structural templates were found to have target partners only in the remote homology range of 18–30%. In this range, nonmetal‐binding templates are calculated to be the majority and serve to predict with 50% sensitivity at the geometric level. Overall, sensitivity at the geometric level for targets having templates in the 18–30% sequence identity range is 73%, with an average of one false positive site per true site. Protein sequences described as “unknown” in the UniProt database and composed largely of unidentified genome project sequences were studied and metal binding sites predicted. A web server for prediction of metal binding sites from protein sequence is provided. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Prediction of optimal CO2 emitter capacity developed for modified atmosphere packaging of fresh salmon fillets (Salmo salar L.)
Authors: Hansen Anlaug Ådland , Høy Martin , Pettersen Marit Kvalvåg
Published: December 2008

Pieces of pre‐rigor filleted Atlantic salmon were modified atmosphere (MA)‐packaged (60% CO2 and 40% N2) in eight different ways according to tray sizes (ml), gas/product ratios (g/p ratios), number of fillet layers and capacities of the CO2 emitters being used (based on the fish weight or on the surface area of the fish). All the samples were stored at 2°C for 21 days.

Gas measurement showed that the CO2 emitter based on fish weight developed too much CO2, and the emitters based on surface area developed too less during storage. Samples with the lowest CO2 level in the headspace (emitter based on surface area), and also probably the lowest amount of absorbed CO2, had the highest bacterial growth after 17 days of storage for some of the samples. Both the pH and the bacterial growth were similar between the top layer and the bottom layer within the packages of more than one layer in each tray. This indicates that the CO2 was also available for the bottom layers. The liquid loss was similar for the trays with the different emitter types, but it differed between the tray sizes.

A model based on the weight and surface area of the fish, and g/p ratio and capacity (ml) of the tray was made in order to more precisely calculate an optimal amount of the CO2 emitter ingredients because of a predefined CO2 level in the headspace. Copyright © 2008 John Wiley & Sons, Ltd.
Pain induced by a single simulated office‐work session: Time course and association with muscle blood flux and muscle activity
Authors: Strøm Vegard , Knardahl Stein , Stanghelle Johan K. , Røe Cecilie
Published: December 2008

The present study aimed to assess the development of pain during computer work with high precision demand and time pressure, and the association between pain and muscle blood fluxes and muscle activity. Twenty‐eight healthy subjects (range 22–44 years) performed a 90‐min standardized task of correcting a text on a word‐processor. Monetary reward was given according to productivity in order to induce time pressure. Pain intensity, general tension, and eye strain were reported on visual analogue scales before, during and after the computer session. Intramuscular trapezius blood fluxes were recorded by laser‐Doppler flowmetry (LDF) and analyzed as % of baseline level. Muscle activity was measured from the upper trapezius and forearm extensors by surface electromyography (EMG), analyzed as % of a maximal calibration contraction, %EMGmax. Pain, tension, and eye strain increased considerably during the computer session with different time course for pain and tension. The LDF of the active side of trapezius was elevated for 30min followed by a falling trend. There was an initial short‐lasting increase in the inactive trapezius. The upper trapezius EMG was low (<3 % of EMGmax) but increased during the work, similar in both the active and passive side. There was a significant time and blood flux interaction effect on pain in the shoulders/neck, but no association with EMG. In conclusion, considerable neck/shoulder pain may develop in healthy pain‐free subjects during 90min of office‐work and seems to be related to the regulation of trapezius muscle blood flow.
Mechanism of arginine regulation of acetylglutamate synthase, the first enzyme of arginine synthesis
Authors: Sancho-Vaello Enea , Fernández-Murga María L. , Rubio Vicente
Published: December 2008

N‐acetyl‐l‐glutamate synthase (NAGS), the first enzyme of arginine biosynthesis in bacteria/plants and an essential urea cycle activator in animals, is, respectively, arginine‐inhibited and activated. Arginine binds to the hexameric ring‐forming amino acid kinase (AAK) domain of NAGS. We show that arginine inhibits Pseudomonas aeruginosa NAGS by altering the functions of the distant, substrate binding/catalytic GCN5‐related N‐acetyltransferase (GNAT) domain, increasing

urn:x-wiley:00145793:media:feb2s001457930800985x:feb2s001457930800985x-math-si1 decreasing V
max and triggering substrate inhibition by AcCoA. These effects involve centrally the interdomain linker, since we show that linker elongation or two‐residue linker shortening hampers and mimics, respectively, arginine inhibition. We propose a regulatory mechanism in which arginine triggers the expansion of the hexameric NAGS ring, altering AAK–GNAT domain interactions, and the modulation by these interactions of GNAT domain functions, explaining arginine regulation.
Dcp1a phosphorylation along neuronal development and stress
Authors: Blumenthal Jacob , Behar Leah , Elliott Evan , Ginzburg Irith
Published: December 2008

Decapping protein 1a (Dcp1a) is found in P‐bodies and functions in mRNA cap removal prior to its degradation. The function and binding partners of Dcp1a have been thoroughly studied, however its expression pattern is still unclear. In this study we have monitored Dcp1a expression along brain development, neuronal differentiation and during cellular stress. We found that Dcp1a is hyperphosphorylated under these physiological conditions. We followed our observations and identified the specific amino acid residues that are phosphorylated. These findings suggest a novel post‐translational modification that may influence the function of Dcp1a in response to various physiological cues.
The intimate and mysterious relationship between proton channels and NADPH oxidase
Authors: Musset Boris , Cherny Vladimir V. , Morgan Deri , DeCoursey Thomas E.
Published: December 2008

Voltage gated proton channels and NADPH oxidase function cooperatively in phagocytes during the respiratory burst, when reactive oxygen species are produced to kill microbial invaders. Although these molecules are distinct entities, with no proven physical interaction, their presence and activity in many cells appears to be coordinated. We describe these interactions and discuss several types of mechanisms that might explain them.
Palaeomagnetic and anisotropy of magnetic susceptibility data bearing on the emplacement of the Western Granite, Isle of Rum, NW Scotland
Authors: PETRONIS M. S. , O'DRISCOLL B. , TROLL V. R. , EMELEUS C. H. , GEISSMAN J. W.
Published: December 2008

The Western Granite is the largest of several granitic bodies around the margin of the Rum Central Igneous Complex. We report palaeomagnetic and anisotropy of magnetic susceptibility (AMS) data that bear on the emplacement and deformation of the Western Granite. The collection includes samples from 27 sites throughout the Western Granite, five sites in adjacent feldspathic peridotite, and two sites in intermediate to mafic hybrid contact aureole rocks. Palaeomagnetic data from 22 of the 27 sites in the granite provide an in situ group mean D = 213.2°, I = −69.5°, α95 = 5.5° that is discordant to an early Paleocene reverse polarity expected field (about 184°, −66°, α95 = 4.3°). The discrepancy is eliminated by removing an inferred 15° of northwest-side-down tilting about a best fit horizontal tilt axis trending 040°. Data from the younger peridotite and hybrid rocks of the Rum Layered Suite provide an in situ group mean of D = 182.6°, I = −64.8°, α95 = 4.0°, which is statistically indistinguishable from an early Paleocene expected field, and imply no post-emplacement tilting of these rocks since remanence acquisition. The inferred tilt recorded in the Western Granite, which did not affect the younger Layered Suite, suggests that emplacement of the ultrabasic rocks resulted in roof uplift and associated tilt of the Western Granite to make space for mafic magma emplacement. Magnetic fabric magnitude and susceptibility parameters yield two subtle groupings in the Western Granite AMS data set. Group 1 data, defined by rocks from exposures to the east and south, have comparatively high bulk susceptibilities (Kmean, 29.51 × 10−3 in SI system), stronger anisotropies (Pj, 1.031) and oblate susceptibility ellipsoids. Group 2 data, from rocks in the west part of the pluton, have lower values of Kmean (15.89 × 10−3 SI) and Pj (1.014), and triaxial susceptibility ellipsoids. Magnetic lineations argue for emplacement of the granite as a tabular sheet from the south–southeast toward the north and west. Moderate to steeply outward-dipping magnetic foliations, together with deflection of the country rock bedding in the north, are consistent with doming accompanying magma emplacement.
Three-dimensional tidal sand waves
Authors: BLONDEAUX PAOLO , VITTORI GIOVANNA
Published: December 2008

The process which leads to the formation of three-dimensional sand waves is investigated by means of a stability analysis which considers the time development of a small-amplitude bottom perturbation of a shallow tidal sea. The weakly nonlinear interaction of a triad of resonant harmonic components of the bottom perturbation is considered. The results show that the investigated resonance mechanism can trigger the formation of a three-dimensional bottom pattern similar to that observed in the field.
Convective/absolute instability in miscible core-annular flow. Part 1: Experiments
Authors: d'OLCE M. , MARTIN J. , RAKOTOMALALA N. , SALIN D. , TALON L.
Published: December 2008

We address the issue of the convective or absolute nature of the instability of core-annular pipe flows, in experiments using two miscible fluids of equal density but different viscosities, the core fluid being much less viscous than the wall one. We use a concentric co-current injection of the two fluids. An axisymmetric parallel base state is obtained downstream the injector. The core radiusRIand the Reynolds numberReof the so-obtained base state are varied independently due to the control of the flow rate of each fluid. However, a downstream destabilization of this base state was observed within the explored range of the two control parametersRIandRe. Moreover, the fixed location of this destabilization, observed for some particular parameters, suggests an absolute nature of the instability. We present a tentative delineation of the nature (convective or absolute) of the instability and discuss the accessible measurements to experimentally address this issue.
Convective/absolute instability in miscible core-annular flow. Part 2. Numerical simulations and nonlinear global modes
Authors: SELVAM B. , TALON L. , LESSHAFFT L. , MEIBURG E.
Published: December 2008

The convective/absolute nature of the instability of miscible core-annular flow with variable viscosity is investigated via linear stability analysis and nonlinear simulations. From linear analysis, it is found that miscible core-annular flows with the more viscous fluid in the core are at most convectively unstable. On the other hand, flows with the less viscous fluid in the core exhibit absolute instability at high viscosity ratios, over a limited range of core radii. Nonlinear direct numerical simulations in a semi-infinite domain display self-excited intrinsic oscillations if and only if the underlying base flow exhibits absolute instability. This oscillator-type flow behaviour is demonstrated to be associated with the presence of a nonlinear global mode. Both the parameter range of global instability and the intrinsically selected frequency of nonlinear oscillations, as observed in the simulation, are accurately predicted from linear criteria. In convectively unstable situations, the flow is shown to respond to external forcing over an unstable range of frequencies, in quantitative agreement with linear theory. As discussed in part 1 of this study (d'Olce, Martin, Rakotomalala, Salin and Talon,J. Fluid Mech., vol. 618, 2008, pp. 305–322), self-excited synchronized oscillations were also observed experimentally. An interpretation of these experiments is attempted on the basis of the numerical results presented here.
Weakly nonlinear thermoacoustics for stacks with slowly varying pore cross-sections
Authors: IN 'T PANHUIS P.H.M.W. , RIENSTRA S. W. , MOLENAAR J. , SLOT J. J. M.
Published: December 2008

A general theory of thermoacoustics is derived for arbitrary stack pores. Previous theoretical treatments of porous media are extended by considering arbitrarily shaped pores with the only restriction that the pore cross-sections vary slowly in the longitudinal direction. No boundary-layer approximation is necessary. Furthermore, the model allows temperature variations in the pore wall. By means of a systematic approach based on dimensional analysis and small parameter asymptotics, we derive a set of ordinary differential equations for the mean temperature and the acoustic pressure and velocity, where the equation for the mean temperature follows as a consistency condition of the assumed asymptotic expansion. The problem of determining the transverse variation is reduced to finding a Green's function for a modified Helmholtz equation and solving two additional integral equations. Similarly the derivation of streaming is reduced to finding a single Green's function for the Poisson equation on the desired geometry.
Low-dimensional models of a temporally evolving free shear layer
Authors: WEI MINGJUN , ROWLEY CLARENCE W.
Published: December 2008

We develop low-dimensional models for the evolution of a free shear layer in a periodic domain. The goal is to obtain models simple enough to be analysed using standard tools from dynamical systems theory, yet including enough of the physics to model nonlinear saturation and energy transfer between modes (e.g. pairing). In the present paper, two-dimensional direct numerical simulations of a spatially periodic, temporally developing shear layer are performed. Low-dimensional models for the dynamics are obtained using a modified version of proper orthogonal decomposition (POD)/Galerkin projection, in which the basis functions can scale in space as the shear layer spreads. Equations are obtained for the rate of change of the shear-layer thickness. A model with two complex modes can describe certain single-wavenumber features of the system, such as vortex roll-up, nonlinear saturation, and viscous damping. A model with four complex modes can describe interactions between two wavenumbers (vortex pairing) as well. At least two POD modes are required for each wavenumber in space to sufficiently describe the dynamics, though, for each wavenumber, more than 90% energy is captured by the first POD mode in the scaled space. The comparison of POD modes to stability eigenfunction modes seems to give a plausible explanation. We have also observed a relation between the phase difference of the first and second POD modes of the same wavenumber and the sudden turning point for shear-layer dynamics in both direct numerical simulations and model computations.
Multi-dimensional instability of dust-ion-acoustic solitary waves in a multi-ion dusty plasma
Authors: ANOWAR M. G. M. , MAMUN A. A.
Published: December 2008

The basic features of obliquely propagating dust-ion-acoustic (DIA) solitary waves, and their multi-dimensional instability in a magnetized multi-ion dusty plasma containing hot adiabatic inertia-less electrons, cold positive and negative ions, and negatively charged static dust have been theoretically investigated by the reductive perturbation method, and the small-k perturbation expansion technique. The combined effects of electron adiabaticity, external magnetic field (obliqueness), and negative ions, which are found to significantly modify the basic properties (speed, amplitude, width, and instability) of small but finite-amplitude DIA solitary waves, are explicitly examined. It is also found that the instability criterion and the growth rate are significantly modified by the external magnetic field, the propagation directions of both the nonlinear waves and their perturbation modes, and the presence of negative ions. The implications of our results in space and laboratory dusty plasmas are briefly discussed.
Hallucinations and two types of free-recall intrusion in schizophrenia
Authors: Brébion G. , David A. S. , Bressan R. A. , Ohlsen R. I. , Pilowsky L. S.
Published: December 2008

Background

Previous research has demonstrated that various types of verbal source memory error are associated with positive symptoms in patients with schizophrenia. Notably, intrusions in free recall have been associated with hallucinations and delusions. We tested the hypothesis that extra-list intrusions, assumed to arise from poor monitoring of internally generated words, are associated with verbal hallucinations and that intra-list intrusions are associated with global hallucination scores.

Method

A sample of 41 patients with schizophrenia was administered four lists of words, followed by free recall. The number of correctly recalled words and the number of extra- and intra-list intrusions were tallied.

Results

The verbal hallucination score was significantly correlated with the number of extra-list intrusions, whereas it was unrelated to the number of correctly recalled words. The number of intra-list intrusions was significantly correlated with the global, but not with the verbal, hallucination score in the subsample of hallucinating patients. It was marginally significantly correlated with the delusion score in delusional patients.

Conclusions

The data corroborate the view that verbal hallucinations are linked to defective monitoring of internal speech, and that errors in context processing are involved in hallucinations and delusions.
Finger counting: The missing tool?
Authors: Andres Michael , Di Luca Samuel , Pesenti Mauro
Published: December 2008

Rips et al. claim that the principles underlying the structure of natural numbers cannot be inferred from interactions with the physical world. However, in their target article they failed to consider an important source of interaction: finger counting. Here, we show that finger counting satisfies all the conditions required for allowing the concept of numbers to emerge from sensorimotor experience through a bottom-up process.
What is still needed? On nativist proposals for acquiring concepts of natural numbers
Authors: Chiang Wen-Chi
Published: December 2008

Rips et al.'s analyses have boosted the plausibility of proposals that the human mind embodies some critical properties of natural numbers. I suggest that such proposals can be further evaluated by infant studies, neuropsychological data, and evolution-based considerations, and additionally, that Rips et al.'s model may need to be modified in order to more completely reflect infants' quantitative abilities.
Counting and arithmetic principles first
Authors: Gelman Rochel
Published: December 2008

The meaning and function of counting are subservient to the arithmetic principles of ordering, addition, and subtraction for positive cardinal values. Beginning language learners can take advantage of their nonverbal knowledge of counting and arithmetic principles to acquire sufficient knowledge of their initial verbal instantiations and move onto a relevant learning path to assimilate input for more advanced, abstract understandings.
Set representations required for the acquisition of the “natural number” concept
Authors: Halberda Justin , Feigenson Lisa
Published: December 2008

Rips et al. consider whether representations of individual objects or analog magnitudes are building blocks for the concept natural number. We argue for a third core capacity – the ability to bind representations of individuals into sets. However, even with this addition to the list of starting materials, we agree that a significant acquisition story is needed to capture natural number.
On some concepts associated with finite cardinal numbers
Authors: Hodes Harold T.
Published: December 2008

I catalog several concepts associated with finite cardinals, and then invoke them to interpret and evaluate several passages in Rips et al.'s target article. Like the literature it discusses, the article seems overly quick to ascribe the possession of certain concepts to children (and of set-theoretic concepts to non-mathematicians).
Specific and general underpinnings to number; parallel development
Authors: Martins-Mourao Antonio , Karmiloff-Smith Annette
Published: December 2008

In this commentary, we outline an epistemological continuum between earlier and later number concepts, showing how empirical findings support the view that specific and general underpinnings to number develop in parallel in children; and we raise the question, based on cross-syndrome comparisons in infancy, as to whether exact or approximate number abilities underlie these later skills.
Mathematical induction and its formation during childhood
Authors: Smith Leslie
Published: December 2008

I support Rips et al.'s critique of psychology through (1) a complementary argument about the normative, modal, constitutive nature of mathematical principles. I add two reservations about their analysis of mathematical induction, arguing (2) for constructivism against their logicism as to its interpretation and formation in childhood (Smith 2002), and (3) for Piaget's account of reasons in rule learning.
Précis ofSemantic Cognition: A Parallel Distributed Processing Approach
Authors: Rogers Timothy T. , McClelland James L.
Published: December 2008

In this précis of our recent book,Semantic Cognition: A Parallel Distributed Processing Approach(Rogers & McClelland 2004), we present a parallel distributed processing theory of the acquisition, representation, and use of human semantic knowledge. The theory proposes that semantic abilities arise from the flow of activation among simple, neuron-like processing units, as governed by the strengths of interconnecting weights; and that acquisition of new semantic information involves the gradual adjustment of weights in the system in response to experience. These simple ideas explain a wide range of empirical phenomena from studies of categorization, lexical acquisition, and disordered semantic cognition. In this précis we focus on phenomena central to the reaction against similarity-based theories that arose in the 1980s and that subsequently motivated the “theory-theory” approach to semantic knowledge. Specifically, we consider (1) how concepts differentiate in early development, (2) why some groupings of items seem to form “good” or coherent categories while others do not, (3) why different properties seem central or important to different concepts, (4) why children and adults sometimes attest to beliefs that seem to contradict their direct experience, (5) how concepts reorganize between the ages of 4 and 10, and (6) the relationship between causal knowledge and semantic knowledge. The explanations our theory offers for these phenomena are illustrated with reference to a simple feed-forward connectionist model. The relationships between this simple model, the broader theory, and more general issues in cognitive science are discussed.
Inductive reasoning and semantic cognition: More than just different names for the same thing?
Authors: Feeney Aidan , Crisp Aimee K. , Wilburn Catherine J.
Published: December 2008

We describe evidence that certain inductive phenomena are associated with IQ, that different inductive phenomena emerge at different ages, and that the effects of causal knowledge on induction are decreased under conditions of memory load. On the basis of this evidence we argue that there is more to inductive reasoning than semantic cognition.
Analogy and conceptual change in childhood
Authors: Opfer John E. , Doumas Leonidas A. A.
Published: December 2008

Analogical inferences are an important consequence of the way semantic knowledge is represented, that is, with relations as explicit structures that can take arguments. We review evidence that this feature of semantic cognition successfully predicts how quickly and broadly children's concepts change with experience and show that Rogers & McClelland's (R&M's) parallel distributed processing (PDP) model fails to simulate these cognitive changes due to its handling of relational information.
Bathymetric constraints on the tectonic and volcanic evolution of Deception Island Volcano, South Shetland Islands
Authors: Barclay A.H. , Wilcock W.S.D. , Ibáñez J.M.
Published: December 2008

Deception Island is the largest volcano in the actively extending Bransfield Basin, a marginal basin situated behind the extinct South Shetland Islands arc. Deception Island has been well studied but its submerged flanks have not. A multibeam bathymetry survey was conducted around the island in 2005. Data from the flooded caldera show no evidence for recent localized resurgence. The gently-sloped bottom of the caldera basin is consistent with either a broad zone of resurgence on its east side associated with trap door deformation or with higher rates of sediment supply from the east side of the island. Around the island, numerous tectonic and volcanic features on the volcano's east and west flanks are nearly all aligned with the regional strike (~060°) of the Bransfield rift and there is very little evidence for the other fault populations that have been identified on the island. We infer that models that link the ongoing tectonic development of Deception Island to complex regional tectonics are less likely than models in which the dominant regional extension in Bransfield Strait is modulated by the local effects of caldera collapse and possibly a small right-lateral transfer zone offsetting the primary extension axes in the Central and Western Bransfield Basins.
Detection of inteins among diverse DNA polymerase genes of uncultivated members of the Phycodnaviridae
Authors: Culley Alexander I , Asuncion Brenda F , Steward Grieg F
Published: December 2008

Viruses in the family Phycodnaviridae infect autotrophic protists in aquatic environments. Application of a PCR assay targeting the DNA polymerase of viruses in this family has revealed that phycodnaviruses are quite diverse and appear to be widespread, but a limited number of environments have been examined so far. In this study, we examined the sequence diversity among viral DNA pol genes amplified by PCR from subtropical coastal waters of O‘ahu, Hawai‘i. A total of 18 novel prasinovirus-like sequences were detected along with two other divergent sequences that differ at the genus-level relative to other sequences in the family. Of the 20 new sequence types reported here, three were serendipitously found to contain protein introns, or inteins. Sequence analysis of the inteins suggested that all three have self-splicing domains and are apparently capable of removing themselves from the translated polymerase protein. Two of the three also appear to be ‘active’, meaning they encode all the motifs necessary for a complete dodecapeptide homing endonuclease, and are therefore capable of horizontal transfer. A subsequent PCR survey of our samples with intein-specific primers suggested that intein-containing phycodnaviruses are common in this environment. A search for similar sequences in metagenomic data sets from other oceans indicated that viral inteins are also widespread, but how these genetic parasites might be influencing the ecology and evolution of phycodnaviruses remains unclear.