bluuebunny/crossref_metadata_2025 huggingface dataset:
Learning sciences
Authors: Nathan Mitchell J. , Wagner Alibali Martha
Published: March 2010

The aims of the learning sciences (LS) are to understand the nature of learning from a broad range of perspectives, and to shape the ways that learning environments and resources are designed and used. LS incorporates bothsystemicandelementalapproaches to investigating questions about learning, as a complement to the primarily elemental approach emphasized in cognitive science research. Thus, its greatest potential is in the integration of systemic and elemental perspectives. Four major themes are central. First, research in LS attempts to bridge the divide between research and practice. Second, research in LS is motivated by limitations of theories of learning and cognition for specifying instruction. Third, research in LS embraces the importance of analyzing and assessing complex interventions through both experimental and design‐based research. Fourth, research in LS emphasizes the learning and behavior of the individual in interaction with the physical, social, and cultural world, as well as with semiotic and technical resources. Research in LS can be conceptualized along a continuum of time scales, from the more microscopic to the more macroscopic. The time‐scale framework illustrates how disparate research traditions and research methods can function within a unifying framework for the study of learning and complex behavior. The effort to ‘scale‐up’ from more elemental findings to more complex, authentic settings has been generative for LS, but faces serious challenges. There is an alternate route to establishing a cumulative scientific knowledge base, namely, ‘scaling down’ from more complex, ecologically valid levels to more elemental levels. Studies of basic learning processes, framed in the context of the larger system, are well positioned to support impact in authentic settings. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Psychology > Development and Aging
Formalism and functionalism in linguistics
Authors: Newmeyer Frederick J.
Published: March 2010

Formalism and functionalism in linguistics are often taken to be diametrically opposed approaches. However, close examination of the relevant phenomena reveals that the two are complementary, rather than being irrevocably in opposition to each other. One can be a formal linguist and a functional linguist at the same time, without there being any contradiction. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Linguistics > Linguistic Theory
Propagation of melting front in structurally heterogeneous media having phase transitions of inhomogeneities
Authors: Savatorova V.L. , Talonov A.V. , Shirochin D.L.
Published: March 2010

Problems of propagation of melting (solidification) front in close to periodical heterogeneous media are studied using a structure homogenization technique. Our method describes not only the averaged behavior of the material of a cell as the classic homogenization techniques do, but also the local behavior of the material within a cell. The generalized formulation of the problems allows us to model more complicated than the commonly studied problems, e.g. problems when the inhomogeneities (e.g.frozen liquid layers) may perturb phase transformation (melting) and change their properties during the propagation of heat front. It is shown that for materials of relatively simple geometry, an analytical solution can be obtained to the heat conductivity problem in the heterogeneous media with phase transformations of the layers. Although the analytical solution to the generalized problem is not as simple as the classic self‐similar solution to the one‐dimensional problem, it keeps some main features of the classic solution. In particular, it is shown that in the case of a fixed heat input, the coordinate of melting front in the direction of the heat transfer is directly proportional to the square root of time. Applications of the new techniques to specific heterogeneous media are presented.
The influence of encounters on domain coarsening
Authors: Niethammer B.
Published: March 2010

We review recent progress on the derivation and analysis of higher order corrections to the classical mean‐field theory of Lifshitz, Slyozov, and Wagner for domain coarsening. Most research on this subject in the applied literature has focussed on the effect of screening induced fluctuations, however some of the resulting models lack self‐consistency. We discuss here recent work in which a self‐consistent model for fluctuations is derived and compare it to a model that has first been suggested in the original paper by Lifshitz and Slyozov. This model takes the effect of encounters between domains into account, but has seemingly gone unnoticed in the literature. Contrary to common expectations self‐similar solutions of this model predict a much larger coarsening rate than the models accounting for fluctuations.
A Kraemer-type Rescaling that Transforms the Odds Ratio into the Weighted Kappa Coefficient
Authors: Warrens Matthijs J.
Published: March 2010

This paper presents a simple rescaling of the odds ratio that transforms the association measure into the weighted kappa statistic for a 2 × 2 table.
Is there Light at the End of the Tunnel? Controversies in the Diagnosis and Management of Carpal Tunnel Syndrome
Authors: Prime Mathew S. , Palmer Jonathan , Goddard Nicholas J. , Khan Wasim S.
Published: March 2010

Carpal tunnel syndrome is a common disorder responsible for considerable patient suffering and cost to health services. Despite extensive research, controversies still exist with regards to best practice in diagnosis, treatment, and service provision. Current best practise would support the use of history, examination and electro-diagnostic studies. The role for ultrasound scanning in diagnosis of carpal tunnel syndrome is yet to be proven. It appears magnetic resonance image scanning has a role where a rare cause for carpal tunnel syndrome may be suspected and also in the detailed reconstruction of the anatomy to aid endoscopic procedures. Treatment options can be surgical or non-surgical and patient choice will dictate the decision. For non-surgical interventions many options have been trialled but until now only steroid use, acupuncture, and splinting have shown discernable benefits. Open surgical decompression of the carpal tunnel appears to be more simple and cost-effective than minimally invasive interventions. For those patients who reject surgery, splinting, acupuncture, and steroid injection can play a role. Recent work looking at different service delivery options has shown some positive results in terms of decreasing patient waiting time for definitive treatment. However, no formal cost-effectiveness analysis has been published and concerns exist about the impact of a stream-lined service on surgical training. In this review, we look at the different diagnostic and treatment options for managing carpal tunnel syndrome. We then consider the different service delivery options and finally the cost-effectiveness evidence.
Synthesis and Surface Properties Characterization of Perfluoroalkylated Oligo(oxyethylene)glycols
Authors: Zaggia Alessandro , Padoan Gennifer , Conte Lino
Published: March 2010

A series of perfluoroalkylated oligo(oxyethylene) glycols as non‐ionic fluorinated surfactants was prepared. The synthesis was performed by adding a molecule of a oligo(oxyethylene)glycol of the general formula HO(CH2CH2O)nOH (n = 1, 2, 4, 6.4, 22.3) to 2‐(perfluorooctylmethyl) oxirane in the presence of catalytic amounts of a Lewis acid. This procedure led to the formation of an amphiphilic molecule characterized by an hydrophobic lipophobic perfluorinated tail and hydrophilic non‐ionic oligo(oxyethylene)chain. Infra red spectroscopy, mass spectroscopy and multinuclear NMR spectroscopy allowed the chemical characterization of the synthesized compounds to be made. Critical micellar concentration, surface tension, interfacial tension and cloud point measurements carries out on aqueous solutions allowed us to evaluate the surface and interfacial properties of the perfluoroalkylated oligo(oxyethylene)glycols. In addition, surface pressure‐area (π, A) diagrams allowed us to determine the principal parameters characterizing the state of their monolayers. The aim of the work was to investigate the effect of the hydrophilic chain length on physical and surface properties.
Brief report: Multilevel analysis of school smoking policy and pupil smoking behaviour in Wales
Authors: Wiium Nora , Burgess Stephen , Moore Laurence
Published: March 2010

A multilevel analysis of cross‐sectional data from a survey involving 1941 pupils (in grades 10 and 11) and policy indicators developed from interviews with staff from 45 secondary schools in Wales examined the hypotheses that pupil smoking prevalence would be associated with: restrictive staff and pupil smoking policies; dissemination of school smoking policies; and implementation of smoking policies in the context of a health promoting whole school environment. The only statistically significant association found was that pupils attending schools that did not disseminate pupil smoking policy in a written document had a greater tendency (OR = 2.16, 95% CI 1.13–4.10) to smoke daily on school premises than those who attended schools that disseminated policy through a written document. This association was not significant (p < 0.05) when pupil level covariates were included. Further research is required to identify the effectiveness and optimal content, enforcement and support of school smoking policies.
Decreased GLT‐1 and increased SOD1 and HO‐1 expression in astrocytes contribute to lumbar spinal cord vulnerability of SOD1‐G93A transgenic mice
Authors: Guo Yansu , Duan Weisong , Li Zhongyao , Huang Jing , Yin Yunxia , Zhang Kunxi , Wang Qian , Zhang Zhifang , Li Chunyan
Published: March 2010

The SOD1‐G93A transgenic mouse is a widely used ALS model, but the death of lower motor neurons is the hallmark. Here, we show that the SOD1‐G93A transgene and HO‐1 are preferentially over‐expressed in the lumbar spinal cord, particularly in the activated astrocytes of the transgenic mice. We also show down‐regulation of GLT‐1 in spite of the proliferating astrocytes. However, GLT‐1, SOD1‐G93A transgene and HO‐1 expression were not obviously changed in the motor cortex. Our data link spinal cord vulnerability to relatively decreased expression of GLT‐1, and high expression of the transgene and HO‐1 in astrocytes in SOD1‐G93A transgenic mice.
The uses of analogy: James Clerk Maxwell's ‘On Faraday's lines of force’ and early Victorian analogical argument
Authors: LAMBERT KEVIN
Published: March 2010

Early Victorian analogical arguments were used to order the natural and the social world by maintaining a coherent collective experience across cultural oppositions such as the ideal and material, the sacred and profane, theory and fact. Maxwell's use of analogical argument in ‘On Faraday's lines of force’ was a contribution to that broad nineteenth-century discussion which overlapped theology and natural philosophy. I argue here that Maxwell understood his theoretical work as both a technical and a socially meaningful practice and that embedding his use of analogy in the social and intellectual context of Victorian Britain provides a means of telling a sociocultural history of Maxwell's development of a new cognitive tool: a way of thinking on paper analogous to thinking with objects in the laboratory.

And analogy can do no more, immediately or directly, than shew such and such things to be true or credible considered only as matters of fact.

Bishop Butler, 17361
Instrumental images: the visual rhetoric of self-presentation in Hevelius's Machina Coelestis
Authors: VERTESI JANET
Published: March 2010

This article places the famous images of Johannes Hevelius's instruments in his Machina Coelestis (1673) in the context of Hevelius's contested cometary observations and his debate with Hooke over telescopic sights. Seen thus, the images promote a crafted vision of Hevelius's astronomical practice and skills, constituting a careful self-presentation to his distant professional network and a claim as to which instrumental techniques guarantee accurate observations. Reviewing the reception of the images, the article explores how visual rhetoric may be invoked and challenged in the context of controversy, and suggests renewed analytical attention to the role of laboratory imagery in instrumental cultures in the history of science.
Disaggregating Deliberation’s Effects: An Experiment within a Deliberative Poll
Authors: Farrar Cynthia , Fishkin James S. , Green Donald P. , List Christian , Luskin Robert C. , Levy Paluck Elizabeth
Published: March 2010

Using data from a randomized field experiment within a Deliberative Poll, this paper examines deliberation’s effects on both policy attitudes and the extent to which ordinal rankings of policy options approach single-peakedness (a help in avoiding cyclical majorities). The setting was New Haven, Connecticut, and its surrounding towns; the issues were airport expansion and revenue sharing – the former highly salient, the latter not at all. Half the participants deliberated revenue sharing, then the airport; the other half the reverse. This split-half design helps distinguish the effects of the formal on-site deliberations from those of other aspects of the treatment. As expected, the highly salient airport issue saw only a slight effect, while much less salient revenue-sharing issue saw a much larger one.
An assessment of the antibacterial activity in larval excretion/secretion of four species of insects recorded in association with corpses, using Lucilia sericata Meigen as the marker species
Authors: Barnes K.M. , Gennard D.E. , Dixon R.A.
Published: March 2010

The relative antibacterial activities of excretion/secretion (ES) from two carrion-feeding insects, Calliphora vicina Robineau-Desvoidy and Dermestes maculatus DeGeer, and a detritivore, Tenebrio molitor Linnaeus, were compared to that of Lucilia sericata Meigen, a species with ES of known antibacterial capacity, in order to explore the antimicrobial potential of other carrion and detritivore species. Viable counts were used to assess time-kill of ES against five bacterial species, Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa and Proteus mirabilis. Antibacterial activity was recorded in all four insect species although T. molitor and D. maculatus were the most effective in controlling growth of P. mirabilis. The blowflies were more effective in controlling a wider range of both Gram-positive and Gram-negative bacteria. The larval ES from all species was shown to reduce bacterial growth rate although differences in antibacterial spectrum were noted and the degree of potency varied between the four species. These differences may be explained ecologically by the different colonisation times of each insect species on the corpse. Overall, this study demonstrates that research into other carrion-feeding insect species has potential to provide an increased source of antimicrobial chemicals to broaden the range of bacterial species beyond that currently controlled using L. sericata.
STRONGLY BOUNDED REPRESENTING MEASURES AND CONVERGENCE THEOREMS
Authors: GHENCIU IOANA , LEWIS PAUL
Published: March 2010

Let K be a compact Hausdorff space, X a Banach space and C(K, X) the Banach space of all continuous functions f: K → X endowed with the supremum norm. In this paper we study weakly precompact operators defined on C(K, X).
Instability of a viscous liquid coating a cylindrical fibre
Authors: GONZÁLEZ ALEJANDRO G. , DIEZ JAVIER A. , GRATTON ROBERTO , CAMPANA DIEGO M. , SAITA FERNANDO A.
Published: March 2010

The instability of a liquid layer coating the surface of a thin cylindrical wire is studied experimentally and numerically with negligible gravity effects. The initial uniform film is obtained as the residual of a sliding drop, and the thickness measurements are performed with an anamorphic optical system that compresses the vertical scale (allowing to observe several wavelengths) and widens the horizontal one (to follow in detail the evolution of local minima and maxima). Experimental timelines showing the growth and position of the maxima and minima are compared with linear theory and fully nonlinear simulations. A primary mode grows in the early stages of the instability, and its wavelength λ1 is not always in agreement with that corresponding to the maximum growth rate predicted by the linear theory λm. In later stages, a secondary mode appears, whose wavelength is half that of the primary mode. The behaviour of the secondary mode allows us to classify the experimental results into two cases, depending on whether it is linearly stable (case I) or unstable (case II). In case I, the amplitude of the secondary mode remains small compared with that of the primary one, while in case II both amplitudes may become very similar at the end. Thus, the distance between the final drops may be quite different from that seen between initial protuberances. The analysis of the experiments allows us to define a simple criterion based on the comparison between λ1 and λm. Contrary to the predictions of widely used previous quasi-static theories, experiments show that the relation between maximum and minimum of the primary mode is better approximated by a kinematic model based on the assumption that primary maxima increase as fast as the minima decrease. Numerical simulations confirm this hypothesis.
Formation of turbulent patterns near the onset of transition in plane Couette flow
Authors: DUGUET Y. , SCHLATTER P. , HENNINGSON D. S.
Published: March 2010

The formation of turbulent patterns in plane Couette flow is investigated near the onset of transition, using numerical simulation in a very large domain of size 800 h × 2 h × 356 h. Based on a maximum observation time of 20 000 inertial units, the threshold for the appearance of sustained turbulent motion is Rec = 324 ± 1. For Rec < Re ≤ 380, turbulent-banded patterns form, irrespective of whether the initial perturbation is a noise or localized disturbance. Measurements of the turbulent fraction versus Re show evidence for a discontinuous phase transition scenario where turbulent spots play the role of the nuclei. Using a smaller computational box, the angle selection of the turbulent bands in the early stages of their development is shown to be related to the amplitude of the initial perturbation.
Determining maximum load-carrying capacity of robots using adaptive robust neural controller
Authors: Korayem M. H. , Alamdari A. , Haghighi R. , Korayem A. H.
Published: March 2010

In this paper, the combination of neural network (NN), proportional derivative (PD), and robust controller are used for determining the maximum load-carrying capacity (MLCC) of articulated robots, subject to both actuator and end-effector deflection constraints. The proposed technique is then applied to articulated robots, and MLCC is obtained for a given trajectory. In the practical simulations, it's impossible to determine the parameters of robot model exactly, so the trajectory tracking performance of the proportional integral derivative (PID) and computed torque methods significantly decrease. The PD control of robot has major problem, it cannot guarantee zero steady state error. For this reason, the NN controller with PD and robust controller are used. The multilayer neural network is also used to compensate gravity and friction effects. By using Lyapunov Direct Method it is shown that the stability of closed loop system would be guaranteed, if the weights of multilayer had certain learning rules. Standard back propagation algorithm is used as a learning algorithm to update the connection weights of the NN controller. The simulation results of the proposed adaptive robust neural network (ARNN) controller are compred with sliding mode and feedback linearization methods for flexible joint robot, and compared with open loop controller for 3D industrial robot. The obtained results assured the robustness and improvement in MLCC in the presence of uncertainties in dynamic model of the robot arm and external disturbances. In fact, adaptive robust NN controller suppresses disturbances accurately and achieves very small errors between commanded and actual trajectories.
COINTEGRATION RANK TESTING UNDER CONDITIONAL HETEROSKEDASTICITY
Authors: Cavaliere Giuseppe , Rahbek Anders , Taylor A.M. Robert
Published: March 2010

We analyze the properties of the conventional Gaussian-based cointegrating rank tests of Johansen (1996, Likelihood-Based Inference in Cointegrated Vector Autoregressive Models) in the case where the vector of series under test is driven by globally stationary, conditionally heteroskedastic (martingale difference) innovations. We first demonstrate that the limiting null distributions of the rank statistics coincide with those derived by previous authors who assume either independent and identically distributed (i.i.d.) or (strict and covariance) stationary martingale difference innovations. We then propose wild bootstrap implementations of the cointegrating rank tests and demonstrate that the associated bootstrap rank statistics replicate the first-order asymptotic null distributions of the rank statistics. We show that the same is also true of the corresponding rank tests based on the i.i.d. bootstrap of Swensen (2006, Econometrica 74, 1699–1714). The wild bootstrap, however, has the important property that, unlike the i.i.d. bootstrap, it preserves in the resampled data the pattern of heteroskedasticity present in the original shocks. Consistent with this, numerical evidence suggests that, relative to tests based on the asymptotic critical values or the i.i.d. bootstrap, the wild bootstrap rank tests perform very well in small samples under a variety of conditionally heteroskedastic innovation processes. An empirical application to the term structure of interest rates is given.
LOCAL RANK ESTIMATION OF TRANSFORMATION MODELS WITH FUNCTIONAL COEFFICIENTS
Authors: Shin Youngki
Published: March 2010

This paper considers a nonparametric functional coefficient model with an unknown link function. The model gives flexibility to the standard interaction-variable model by allowing an arbitrary functional form of heterogeneous marginal effects.A local rank estimation procedureis proposed for the functional coefficients along with its asymptotic property.
A NEW PROJECTION-TYPE SPLIT-SAMPLE SCORE TEST IN LINEAR INSTRUMENTAL VARIABLES REGRESSION
Authors: Chaudhuri Saraswata , Richardson Thomas , Robins James , Zivot Eric
Published: March 2010

In this paper we introduce a new method of projection-type inference and describe it in the context of two stage least squares–based split-sample inference on subsets of structural coefficients in a linear instrumental variables regression model. The use of the new method not only guards against the uncontrolled overrejection of the true value of the parameters of interest but also reduces the conservativeness of the usual method of projection proposed by Dufour and his coauthors (Dufour, 1997,Econometrica65, 1365–1388; Dufour and Jasiak, 2001,International Economic Review41, 815–843; Dufour and Taamouti, 2005, discussion paper; Dufour and Taamouti, 2005,Econometrica73, 1351–1365; Dufour and Taamouti, 2007,Journal of Econometrics139, 133–153).
Implicational markedness and frequency in constraint-based computational models of phonological learning
Authors: JAROSZ GAJA
Published: March 2010

This study examines the interacting roles of implicational markedness and frequency from the joint perspectives of formal linguistic theory, phonological acquisition and computational modeling. The hypothesis that child grammars are rankings of universal constraints, as in Optimality Theory (Prince & Smolensky, 1993/2004), that learning involves a gradual transition from an unmarked initial state to the target grammar, and that order of acquisition is guided by frequency, along the lines of Levelt, Schiller & Levelt (2000), is investigated. The study reviews empirical findings on syllable structure acquisition in Dutch, German, French and English, and presents novel findings on Polish. These comparisons reveal that, to the extent allowed by implicational markedness universals, frequency covaries with acquisition order across languages. From the computational perspective, the paper shows that interacting roles of markedness and frequency in a class of constraint-based phonological learning models embody this hypothesis, and their predictions are illustrated via computational simulation.
Population-based surveillance study ofCampylobacterinfections in Finland
Authors: NAKARI U.-M. , HUOVINEN E. , KUUSI M. , SIITONEN A.
Published: March 2010

The annual incidence in 14 361 campylobacteriosis cases reported in Finland in 2002–2005 varied between 61 and 76/100 000 population. The mean incidence was highest (148/100 000) in the 25–29 years age group and lowest (range 21–24/100 000) in children aged 5–14 years and patients aged ⩾75 years. The number of domestic cases was low in winter and peaked in summer. A total of 622 strains isolated from domestic infections and 785 foreign travel-related strains were serotyped. Serotypes Pen 3 and Pen 37 had the strongest association with travel-related infections (96%,P<0·001), and Pen 6,7, Pen 12 and Pen 27 were significantly associated with domestic infections (>70% domestic within each serotype,P<0·001). Pen 2 and Pen 1,44 were less common in older than in younger patients. Of domestic strains, a higher proportion of Pen 2 strains was isolated in winter (18%) compared to the other serotypes (0–10%).
Morphologic and molecular diversity of the foraminiferal genusGlobocassidulinain Admiralty Bay, King George Island
Authors: Majewski Wojciech , Pawlowski Jan
Published: March 2010

Four distinctive morphological types can be found among livingGlobocassidulinain surface sediments of Admiralty Bay (King George Island, South Shetland Islands). The molecular analysis of the SSU and ITS rDNA indicates that they are monospecific and belong toGlobocassidulina biora, except for minute forms from deeper than 200 m water depth which probably representG. subglobosa. The morphological types ofG. biorathat show doubled or branched apertures, varied test size and shape as well as colour of cytoplasm, represent populations at different stages of ontogenetic development. However, the variability among largeG. biorafrom the same locations is difficult to comprehend. It seems probable thatG. biorais the only recent, large, shallow waterGlobocassidulinarepresented throughout the Antarctica, whileG. crassais typical for the Magellan region.
The paediatric cardiology Hall of Fame: Maude Elizabeth Abbott
Authors: Evans William N. , Béland Marie J.
Published: March 2010

Few paediatric cardiologists know of Maude Abbott. Yet before Helen Taussig, no one contributed more to founding the speciality than Maude Abbott. She achieved international fame as the early 20th century expert on cardiac malformations. We summarise here her life and contributions, indicating how she is more than justified in being inducted to the Hall of Fame.
Detecting changes in seasonal precipitation extremes using regional climate model projections: Implications for managing fluvial flood risk
Authors: Fowler H. J. , Wilby R. L.
Published: March 2010

There is growing evidence of coherent, global patterns of change in annual precipitation and runoff with high latitudes experiencing increases consistent with climate model projections. This paper describes a methodology for estimating detection times for changes in seasonal precipitation extremes. The approach is illustrated using changes in UK precipitation projected by the European Union PRUDENCE climate model ensemble. We show that because of high variability from year to year and confounding factors, detection of anthropogenic climate change at regional scales is not generally expected for decades to come. Overall, the earliest detection times were found for 10 day winter precipitation totals with 10 year return period in SW England. In this case, formal detection could be possible within a decade from now if the climate model projections are realized. The outlook for changes in summer flash flood risk is highly uncertain. Our analysis further demonstrates that existing precautionary allowances for climate change used for flood management may not be sufficiently robust in NE England and east Scotland. These findings imply that for certain types of flood mechanism, adaptation decisions might have to be taken in advance of formally detected changes in flood risk. This reinforces the case for long‐term environmental monitoring and reporting of climate change indices at “sentinel” locations.
Flow rate perturbations in a black smoker hydrothermal vent in response to a mid‐ocean ridge earthquake swarm
Authors: Crone Timothy J. , Wilcock William S. D. , McDuff Russell E.
Published: March 2010

Although there is indirect evidence for strong connections between tectonic processes and mid‐ocean ridge hydrothermal flow, there are no direct observations of these links, primarily because measuring flow in these systems is difficult. Here we use an optical analysis technique to obtain a 44 day record of flow rate changes in a black smoker vent in the Main Endeavour field of the Juan de Fuca Ridge. We show that variations in the flow rate coincide with an earthquake swarm observed using an ocean bottom seismometer array. These observations indicate that connections between tectonics and flow are indeed strong, that hydraulic connections within this hydrothermal system are long ranging, and that enhanced tidal pumping of fluids may be initiated by earthquake activity. Because the effects of the swarm cross over an intervening vent field, we infer that the upflow zones feeding this field are narrow. Using the time lag between the swarm onset and the flow rate changes we estimate that the bulk permeability of the crust on the Endeavour segment ranges from 3.0 × 10−13 m2 to 6.0 × 10−12 m2.
Mid‐Brunhes strengthening of the Indian Ocean Dipole caused increased equatorial East African and decreased Australasian rainfall
Authors: Gupta Anil K. , Sarkar Sudipta , De Soma , Clemens Steven C. , Velu Angamuthu
Published: March 2010

The tropical Indian Ocean is an important component of the largest warm pool, marked by changes in sea surface temperatures and depths of thermocline and mixed layer in its western and eastern extremities leading to the development of a dipole mode ‐ the Indian Ocean Dipole (IOD). A narrow band of westerlies (7°N to 7°S) sweep the equatorial Indian Ocean during the April–May and October–November transitions between the summer‐ and winter‐monsoon seasons. These Indian Ocean equatorial westerlies (IEW) are closely related to the IOD, intensifying the upper ocean Eastward Equatorial current also known as Wyrtki jets. The strength of the IOD/IEW determines the moisture content in East Africa. A major decrease in the strength of the IEW (strengthening or positive mode of the IOD) during the mid‐Brunhes epoch (∼300–250 Kyr BP) coincides with a wetter equatorial East Africa, a drier Australasia and a stronger Indian summer monsoon, indicating that the IOD/IEW play a significant role in driving climate change in East Africa, Australasia and South Asia.
Analytical model of infiltration under constant‐concentration boundary conditions
Authors: Triadis D. , Broadbridge P.
Published: March 2010

Known integrable models for 1D flow in unsaturated soil have a rescaled soil water diffusivity that is either constant or proportional to C(C − 1)/(C − Θ)2, where Θ is the degree of saturation and C > 1 is constant. With a wider more realistic range of hydraulic conductivity functions than has been used in this context before, a formal series solution is developed for infiltration, subject to constant‐concentration boundary conditions. A readily programmed iteration algorithm, applicable for any value of C, is used to construct many coefficients of the infiltration series without requiring any numerical integration. In particular, for either C − 1 small or 1/C small, several infiltration series coefficients are constructed as formal power series in C − 1 or in 1/C, for which we construct a number of terms explicitly. In the limit as the diffusivity approaches a delta function, the infiltration coefficients are obtained in simpler closed form. All but the sorptivity depend on the form of the conductivity function.
Lattice relaxation process and crystallographic tilt in GaP layers grown on misoriented Si(001) substrates by metalorganic vapor phase epitaxy
Authors: Takagi Yasufumi , Furukawa Yuzo , Wakahara Akihiro , Kan Hirofumi
Published: March 2010

A lattice relaxation process and a crystallographic tilt in GaP layers grown on misoriented Si(001) substrates by metalorganic vapor phase epitaxy were investigated. Strained pseudomorphic GaP layers without defects on Si were successfully achieved by the optimization of growth conditions. Below critical thickness, the strained GaP layers were tilted in the misoriented direction of the Si substrates and triclinically distorted. Above critical thickness, the residual strain in the GaP layers was progressively relaxed with increased thickness of the GaP layers by forming 60° misfit dislocations propagating to the two orthogonal ⟨110⟩ directions at the heterointerface. X-ray diffuse scattering around the symmetrical GaP(004) diffraction was observed after introducing misfit dislocations. Diffuse scattering became dominant with an increase in the density of the misfit dislocations and resulted in a broadening of the full width at half maximum of the x-ray rocking curves. The GaP layers that were relaxed with highly dense misfit dislocations were tilted opposite of the misoriented direction due to the imbalance nucleation of the misfit dislocations on each {111} glide plane.
Well posedness for the nonlinear Klein–Gordon–Schrödinger equations with heterointeractions
Authors: Shi Qihong , Wang Shu , Li Yong , Wang Changyou
Published: March 2010

In this paper we study the well posedness of solution to a certain system of nonlinear Klein–Gordon–Schrödinger equations in three space dimensions. Basing on the Strichartz estimates, we obtain the global existence, uniqueness of the solutions, and continuous dependence with respect to initial data in the Sobolev spaces of low regularities by setting appropriate contraction and taking difference estimates.
Direct observation of ferroelectric domains created by Wigner crystallization of electrons in α-[bis(ethylenedithio)tetrathiafulvalene]2I3
Authors: Yamamoto Kaoru , Kowalska Aneta Aniela , Yakushi Kyuya
Published: March 2010

The organic conductor α-[bis(ethylenedithio)tetrathiafulvalene]2I3 undergoes a ferroelectric transition due to the Wigner-crystal-like charge ordering. The present paper reports the direct observation of 180° polar domains growing in the ferroelectric phase by means of optical second-harmonic generation interferometry. Mapping observation of the nonlinear optical interference revealed the development of large polar domains, illustrating a strong tendency of single-domain growth in the ferroelectric compound. The domain structures were varied when the crystal was annealed above the transition temperature and recooled into the ferroelectric phase. The variation indicates the mobile nature of the domains in the ferroelectric organic conductor.
Indium substituted PrCo5 sintered magnet: A microstructure view
Authors: Li W. F. , Gabay A. M. , Ni C. , Hadjipanayis G. C.
Published: March 2010

Indium addition in PrCo5 magnets can facilitate their sintering and improve their coercivity significantly. Transmission electron microscope studies showed the presence of indium-rich phase PrCo2In, at the intergranular region in the sintered Pr18Co81.5In0.5 magnets annealed at 800 and 950 °C. Another new ternary phase, Pr3Co9In2, appeared only in magnets annealed at 950 °C. Both of these phases are believed to be helpful to improve the sintering behavior of the magnets. Especially, the Pr3Co9In2 phase is observed in the form of a thin layer along the grain boundaries, which is believed to improve the magnetic performance of the magnet.
Valence band and core-level analysis of highly luminescent ZnO nanocrystals for designing ultrafast optical sensors
Authors: Joshi Amish G. , Sahai Sonal , Gandhi Namita , Krishna Y. G. Radha , Haranath D.
Published: March 2010

The detailed surface analysis such as survey scan, core-level, and valence band spectra of highly luminescent ZnO:Na nanocrystals were studied using the x-ray photoelectron spectroscopy to establish the performed presence of Na+ ions. The observed increase in band gap from 3.30 (bulk) to 4.16 eV (nano), is attributed to the quantum confinement of the motion of electron and holes in all three directions. The photoluminescence and decay measurements have complemented and supported our study to design an efficient and ultrafast responsive optical sensing device.
Breaking through the glass ceiling: The correlation between the self-diffusivity in and krypton permeation through deeply supercooled liquid nanoscale methanol films
Authors: Smith R. Scott , Matthiesen Jesper , Kay Bruce D.
Published: March 2010

Molecular beam techniques, temperature-programmed desorption (TPD), and reflection absorption infrared spectroscopy (RAIRS) are used to explore the relationship between krypton permeation through and the self-diffusivity of supercooled liquid methanol at temperatures (100–115 K) near the glass transition temperature, Tg (103 K). Layered films, consisting of CH3OH and CD3OH, are deposited on top of a monolayer of Kr on a graphene covered Pt(111) substrate at 25 K. Concurrent Kr TPD and RAIRS spectra are acquired during the heating of the composite film to temperatures above Tg. The CO vibrational stretch is sensitive to the local molecular environment and is used to determine the supercooled liquid diffusivity from the intermixing of the isotopic layers. We find that the Kr permeation and the diffusivity of the supercooled liquid are directly and quantitatively correlated. These results validate the rare-gas permeation technique as a tool for probing the diffusivity of supercooled liquids.
Ionic doping effect in ZrO2 resistive switching memory
Authors: Zhang Haowei , Gao Bin , Sun Bing , Chen Guopeng , Zeng Lang , Liu Lifeng , Liu Xiaoyan , Lu Jing , Han Ruqi , Kang Jinfeng , Yu Bin
Published: March 2010

Oxygen vacancy (VO) plays the critical role for resistive switching in transition metal oxide resistive random access memory (RRAM). First principles calculation is performed to study the impact of metallic ion (Al, Ti, or La) doping in ZrO2 on the behaviors of VO, including defect energy level and formation energy (Evf). Trivalent dopant (Al or La) significantly reduces Evf. Based on the calculated results, ZrO2-based RRAM devices are designed to control the formation of VO, and improved resistive switching uniformity is demonstrated in experiments.
Monolithic integration of plasmonic waveguides into a complimentary metal-oxide-semiconductor- and photonic-compatible platform
Authors: Sederberg S. , Van V. , Elezzabi A. Y.
Published: March 2010

A silicon-based plasmonic waveguide was designed and fabricated for use at telecommunications wavelengths. This waveguide is interfaced to the silicon photonics platform by use of a tapered silicon-on-insulator waveguide. Simulations indicate that this scheme excites the transverse magnetic plasmonic mode and that the electric fields are confined to the silicon-gold interface. Transmitted power is measured for several device lengths and the propagation distance and coupling efficiency are found to be 2.00 μm and 38.0%, respectively. These results demonstrate the potential for integration between silicon photonics and silicon plasmonic devices and demonstrate the ability to incorporate silicon-based plasmonic devices into complimentary metal-oxide-semiconductor electronic and photonic circuitry.
Gold-free GaAs/GaAsSb heterostructure nanowires grown on silicon
Authors: Plissard S. , Dick K. A. , Wallart X. , Caroff P.
Published: March 2010

Growth of GaAs/GaAsSb heterostructure nanowires on silicon without the need for gold seed particles is presented. A high vertical yield of GaAs nanowires is first obtained, and then GaAsxSb1-x segments are successfully grown axially in these nanowires. GaAsSb can also be integrated as a shell around the GaAs core. Finally, two GaAsSb segments are grown inside a GaAs nanowire and passivated using an AlxGa1-xAs shell. It is found that no stacking faults or twin planes occur in the GaAsSb segments.
Hypersonic acoustic mirrors and microcavities in porous silicon
Authors: Aliev G. N. , Goller B. , Kovalev D. , Snow P. A.
Published: March 2010

Periodic solid state structures exhibit transmission stop bands for waves of certain frequencies. We report the realization and direct measurement of acoustic band gaps in porous silicon multilayer structures which exhibit ∼50 dB stop bands for longitudinal acoustic waves in the gigahertz range. Furthermore, realization of an acoustic microcavity structure in porous silicon is demonstrated.
Boron-tuned bonding mechanism of Li-graphene complex for reversible hydrogen storage
Authors: Liu Chun-Sheng , Zeng Zhi
Published: March 2010

Based on first-principles density functional theory, we show that boron-doping significantly enhances the Li bond strength on the graphene. The transition from s–p hybridization of the Li-graphene complex to p–p hybridization of the Li-coated boron-doped graphene is responsible for the enhanced binding energy. The charge redistribution induced by boron-doping gives rise to two parts of an electrostatic potential energy (one is around the Li atom and the other is parallel to the graphene plane). Four polarized H2 molecules are attached to one Li atom with an optimal binding energy of ∼0.13 eV/H2.
Divacancies and the hydrogenation of Mg-Ti films with short range chemical order
Authors: Leegwater H. , Schut H. , Egger W. , Baldi A. , Dam B. , Eijt S. W. H.
Published: March 2010

We obtained evidence for the partial chemical segregation of as-deposited and hydrogenated Mg1−yTiy films (0≤y≤0.30) into nanoscale Ti and Mg domains using positron Doppler-broadening. We exclusively monitor the hydrogenation of Mg domains, owing to the large difference in positron affinity for Mg and Ti. The electron momentum distribution broadens significantly upon transformation to the MgH2 phase over the whole compositional range. This reveals the similarity of the metal-insulator transition for rutile and fluorite MgH2. Positron lifetime studies show the presence of divacancies in the as-deposited and hydrogenated Mg-Ti metal films. In conjunction with the relatively large local lattice relaxations we deduce to be present in fluorite MgH2, these may be responsible for the fast hydrogen sorption kinetics in this MgH2 phase.
Radicalism, Antiracism, and Nostalgia: The Burden of Loss in the Search for Convivial Culture
Authors: Bonnett Alastair
Published: March 2010

Drawing on the example of British antiracism, I argue that nostalgia is an integral and constitutive force within the radical imagination. The first section of the paper is historical and contextual. It shows how attachments to the past and associated feelings of loss and regret (attachments and emotions which combine to form nostalgia) became marginalised and repressed within modern radicalism. The second section looks at how antinostalgia and nostalgia were mapped onto radical antiracism in Britain in the 1980s. It is suggested that the stereotype of the ‘black rebel’ concealed and cohered the tensions between a declining socialist movement and the politics of loss. The third part of the paper explores the issue of nostalgia in the company of Gilroy's After Empire: Melancholia or Convivial Culture? My critique of After Empire is in two parts. First I look at the stereotyping and repression of themes of loss that sustain Gilroy's account. Second, I address After Empire as a nostalgic text, burdened with a yearning for lost political potency. The essay concludes with a call for radicals and antiracists to move beyond the a priori suspicion of nostalgia.
Territorial Politics in Hard Times: The Welfare State under Pressure in Germany, Spain, and the United Kingdom
Authors: Greer Scott
Published: March 2010

The author argues that the design of decentralized political institutions shapes the effect of economic crisis on the welfare state. He proposes a simple framework for understanding the effects of crisis on areas under the responsibility of regional governments: their responses and mediating effects will vary with the financial system, degree of regional input into central decisions, and legal framework. Further, the ways in which territorial political institutions channel economic pressures should lead to changing territorial politics as the relative resources and credibility of governments change. The author discusses the influence of territorial political institutions on responses to economic crisis in Germany, Spain, and the UK. It is concluded that Germany is most likely to proceed unchanged, Spain might see the hardest landing due to the difficult finances of many regional governments, and devolution in the UK is economically sustainable and limits negative welfare-state effects but might be politically unsustainable. The conclusion suggests that welfare-state analysis should take more account of specific territorial political institutions, that further analysis should include local government, and that economic pressure might reshape territorial politics in at least some countries.
Does Nationalism Trigger Welfare-State Disintegration? Social Policy and Territorial Mobilization in Belgium and Canada
Authors: Béland Daniel , Lecours André
Published: March 2010

Since the late 1990s a growing number of scholars have explored the relationship between decentralization, nationalism, and social policy development. In this paper we explore the impact of substate nationalism on the territorial integration or disintegration of the welfare state in Belgium and Canada. As argued, although substate nationalist mobilization is intuitively associated with welfare-state disintegration, there is little evidence to support this claim. In Belgium, despite Flemish nationalist pressures, francophone opposition and major constitutional obstacles have prevented the decentralization of the federal social insurance system. In Canada competitive nation building between the federal and Quebec governments has not led to the erosion of social protection. Instead, this logic has favored the creation of a decentralized and asymmetrical welfare state while exacerbating pressures for social policy expansion. In order to explain such contrasted outcomes we draw on the existing scholarship on the role of ideas and of institutions in policy development.
Doug Hilton: At home with blood cell biology
Authors: Sedwick Caitlin
Published: March 2010

Hilton's passion for blood makes his pulse race.
The Arf tumor suppressor protein inhibits Miz1 to suppress cell adhesion and induce apoptosis
Authors: Herkert Barbara , Dwertmann Anne , Herold Steffi , Abed Mona , Naud Jean-Francois , Finkernagel Florian , Harms Gregory S. , Orian Amir , Wanzel Michael , Eilers Martin
Published: March 2010

Oncogenic stress induces expression of the alternate reading frame (Arf) tumor suppressor protein. Arf then stabilizes p53, which leads to cell cycle arrest or apoptosis. The mechanisms that distinguish both outcomes are incompletely understood. In this study, we show that Arf interacts with the Myc-associated zinc finger protein Miz1. Binding of Arf disrupts the interaction of Miz1 with its coactivator, nucleophosmin, induces the sumoylation of Miz1, and facilitates the assembly of a heterochromatic complex that contains Myc and trimethylated H3K9 in addition to Miz1. Arf-dependent assembly of this complex leads to the repression of multiple genes involved in cell adhesion and signal transduction and induces apoptosis. Our data point to a tumor-suppressive pathway that weakens cell–cell and cell–matrix interactions in response to expression of Arf and that may thereby facilitate the elimination of cells harboring an oncogenic mutation.