bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of induced dissipative small-scale motions and mixing on optical distortion in a plane shear layer
Authors: OLJACA MIODRAG , GLEZER ARI
Published: December 2008

Optical distortion through a plane shear layer between two uniform streams of unequal temperatures is investigated using imaging of scalar mixing by planar laser-induced fluorescence (LIF). Simultaneous fluorescence intensity measurements of disodium fluorescein and rhodamine B (the fluorescence of the latter is temperature dependent) are used to extract the temperature distribution within the plane of a laser sheet. This planar imaging technique allows a direct measurement of the index of refraction field, which is used to determine optical distortions in the imaging plane. While a given ray within the sheet is refracted at a cumulative angle that depends on the local index of refraction gradient along its path, LIF measurements in the cross-stream plane of the flow show substantial optical distortions near the upstream and downstream edges of the primary vortices where the angle between the local temperature (or index) gradient and the wavevector of the incident light is large. These distortions are manifested by the appearance of low- and high-intensity streaks that are advected with the flow and whose characteristic spatial scales significantly diminish with the onset of small-scale (mixing) transition. The formation of secondary (streamwise) vortical structures leads to substantial spanwise variations in index of refraction and consequently to optical distortions that vary with the phase of the base flow and can exceed the distortions in the cross-stream plane. An important aim of the present research is the investigation of the effects of direct actuation of small-scale motions on the mixing and consequently on optical distortion within the shear layer. The actuation suppresses the formation of the large coherent vortical structures and leads to localized enhancement of dissipation and reduction in turbulent kinetic energy. The actuation enhances mixing across the entire width of the forced shear layer and leads to significant reduction of optical distortion, suggesting that active small-scale mixing can play a significant role in the mitigation of aero-optical effects through turbulent shear flows.
Turbulent dynamics of pipe flow captured in a reduced model: puff relaminarization and localized ‘edge’ states
Authors: WILLIS ASHLEY P. , KERSWELL RICH R.
Published: December 2008

Fully three-dimensional computations of flow through a long pipe demand a huge number of degrees of freedom, making it very expensive to explore parameter space and difficult to isolate the structure of the underlying dynamics. We therefore introduce a ‘2+ε-dimensional’ model of pipe flow, which is a minimal three-dimensionalization of the axisymmetric case: only sinusoidal variation in azimuth plus azimuthal shifts are retained; yet the same dynamics familiar from experiments are found. In particular the model retains the subcritical dynamics of fully resolved pipe flow, capturing realistic localized ‘puff-like’ structures which can decay abruptly after long times, as well as global ‘slug’ turbulence. Relaminarization statistics of puffs reproduce the memoryless feature of pipe flow and indicate the existence of a Reynolds number about which lifetimes diverge rapidly, provided that the pipe is sufficiently long. Exponential divergence of the lifetime is prevalent in shorter periodic domains. In a short pipe, exact travelling-wave solutions are found near flow trajectories on the boundary between laminar and turbulent flow. In a long pipe, the attracting state on the laminar–turbulent boundary is a localized structure which resembles a smoothened puff. This ‘edge’ state remains localized even for Reynolds numbers at which the turbulent state is global.
The shape of submarine levees: exponential or power law?
Authors: BIRMAN V. K. , MEIBURG E. , KNELLER B.
Published: December 2008

Field observations indicate that the height of submarine levees decays with distance from the channel either exponentially or according to a power law. This investigation clarifies the flow conditions that lead to these respective shapes, via a shallow water model for the overflow currents that govern the levee formation. The model is based on a steady state balance of sediment supply by the turbidity current, and sediment deposition onto the levee, with the settling velocity and the entrainment rate appearing as parameters. It demonstrates that entrainment of ambient fluid is the determining factor for the levee shape. For negligible entrainment rates, levee shapes tend to exhibit exponential profiles, while constant rates of entrainment or detrainment result in power law shapes. Interestingly, whether a levee has an exponential or a power law shape is determined by kinematic considerations only, viz. the balance laws for sediment mass and fluid volume. We find that the respective coefficients governing the exponential or power law decay depend on the settling speeds of the sediment grains, which in turn is a function of the grain size. Two-dimensional, unsteady Navier–Stokes simulations confirm the emergence of a quasi-steady state. The depositional behaviour of this quasi-steady state is consistent with the predictions of the shallow water model, thus validating the assumptions underlying the model, and demonstrating its predictive abilities.
Discrimination of English and Thai words ending with voiceless stops by native Thai listeners differing in English experience
Authors: Tsukada Kimiko , Roengpitya Rungpat
Published: December 2008

This study examines the discrimination of words ending with voiceless stops /p t k/ in first language (L1) and second language (L2) by three groups of native Thai participants. These participants differed in their countries of residence and experience with L2 English in the formal education system. The first group (T1) was a group of 18 Thai listeners who were living in Australia. The second and third groups consisted of 12 university students (T2) and 12 high-school students (T3) living in Thailand. Eighteen Australian English (AusE) listeners were included as controls. English and Thai words minimally contrasting in the final stop (e.g. ‘cap’ vs. ‘cat’) were presented to the listeners to investigate whether L2 phonetic learning occurs even for the contrasts that are expected to be discriminated with high accuracy from the onset of L2 learning and if so, how it is influenced by L2 experience. All three Thai groups showed reasonably accurate discrimination for both English and Thai words, but only T1 showed discrimination accuracy comparable to AusE in English. Further, only T3 was clearly more accurate in discriminating unreleased Thai than English stop contrasts, most of which were accompanied with release bursts. These two findings are taken to be evidence for phonetic learning of specific aspects of L2 contrasts rather than positive L1 transfer.
A book not to be embraced: A critical appraisal of Stacy Johnson's A Time to Embrace
Authors: Gagnon Robert A. J.
Published: December 2008

I wish that I could commend William Stacy Johnson's book, A Time to Embrace, as a rigorous and fair assessment of Christianity and homosexuality from a homosexualist perspective. Unfortunately, Johnson so regularly violates scholarly standards for honesty and accuracy in representing secondary literature, conceals from readers the most important counter-arguments to his position and shows gaps in logic, that I cannot embrace A Time to Embrace. Given space constraints, it is impossible to give a systematic presentation of the book's errors in fact or argumentation. I refer readers to my website for material that could not fit here and for a rejoinder to Johnson's response (http://robgagnon.net/ArticlesOnline.htm).
Newton, Locke and the Trinity: Sir Isaac's comments on Locke's:A Paraphrase and Notes on the Epistle of St Paul to the Romans
Authors: Parker Kim Ian
Published: December 2008

Until the recent discovery of a page of Isaac Newton's observations on John Locke'sParaphrase and Notes on St Paul's Epistle to the Romans, it was not known whether Newton had received or remarked upon Locke's work or, in turn, whether Locke had ever received Newton's comments. Since its discovery, however, it is possible to trace Locke's corrections and speculate on the extent and direction to which Newton may have influenced Locke. This article first establishes the theological relationship between Newton and Locke and, second, argues that Locke's revisions in light of Newton's suggestions reveal an anti-trinitarian spirit to his discussion. A previously unpublished transcription of Newton's manuscript fragment is also included.
Finding our way forward
Authors: Johnson William Stacy
Published: December 2008

I thank the editor for the opportunity to respond to two forceful conservative critics of my position. As everyone knows, this is a controversy that threatens to split churches and divide society. Yet there is also hope for a way forward.
Iodine status in a Sherpa community in a village of the Khumbu region of Nepal
Authors: Heydon Emma E , Thomson Christine D , Mann Jim , Williams Sheila M , Skeaff Sheila A , Sherpa Kami T , Heydon John L
Published: December 2008

Objective

To assess the iodine status of Sherpa residents living in Kunde village, Khumbu region, Nepal.

Design

Prevalence of goitre was determined by palpation. Urinary iodine concentrations (UIC) were determined in casual morning samples, and thyroid-stimulating hormone (TSH) in finger-prick blood samples on filter paper. Dietary and demographic data were obtained via questionnaire, and selected foods analysed for iodine.

Setting

Khumbu region is an area of low soil iodine in Nepal, where the prevalence of goitre was greater than 90 % in the 1960s prior to iodine intervention.

Subjects

Two hundred and fifteen of 219 permanent residents of Kunde were studied.

Results

Overall prevalence of goitre was 31 % (Grade 1 goitre, 27·0 %; Grade 2, 4·2 %). When adjusted to a world population, goitre prevalence was 27 % (95 % CI 23, 32 %); Grade 2 goitre prevalence was 2·8 % (95 % CI 1·0, 4·6 %). Median UIC was 97 μg/l, but only 75 μg/l in women of childbearing age. Thirty per cent had UIC < 50 μg/l and 52 % had UIC < 100 μg/l, while 31 % of children aged <14 years had UIC > 300 μg/l. Ten per cent of participants had TSH concentrations >5 μU/ml.

Conclusions

The prevalence of severe iodine deficiency has decreased since the 1960s, but mild iodine deficiency persists, particularly in women of childbearing age. The consumption of high-iodine uncooked instant noodles and flavour sachets by school-aged children contributed to their low prevalence of goitre and excessive UIC values. This finding may obscure a more severe iodine deficiency in the population, while increasing the risk of iodine-induced hyperthyroidism in children. Ongoing monitoring is essential.
Socio-environmental, personal and behavioural predictors of fast-food intake among adolescents
Authors: Bauer Katherine W , Larson Nicole I , Nelson Melissa C , Story Mary , Neumark-Sztainer Dianne
Published: December 2008

Objective

To identify the socio-environmental, personal and behavioural factors that are longitudinally predictive of changes in adolescents’ fast-food intake.

Design

Population-based longitudinal cohort study.

Setting

Participants from Minnesota schools completed in-class assessments in 1999 (Time 1) while in middle school and mailed surveys in 2004 (Time 2) while in high school.

Subjects

A racially, ethnically and socio-economically diverse sample of adolescents (n 806).

Results

Availability of unhealthy food at home, being born in the USA and preferring the taste of unhealthy foods were predictive of higher fast-food intake after 5 years among both males and females. Among females, personal and behavioural factors, including concern about weight and use of healthy weight-control techniques, were protective against increased fast-food intake. Among males, socio-environmental factors, including maternal and friends’ concern for eating healthy food and maternal encouragement to eat healthy food, were predictive of lower fast-food intake. Sports team participation was a strong risk factor for increased fast-food intake among males.

Conclusions

Our findings suggest that addressing socio-environmental factors such as acculturation and home food availability may help reduce fast-food intake among adolescents. Additionally, gender-specific intervention strategies, including working with boys’ sports teams, family members and the peer group, and for girls, emphasizing the importance of healthy weight-maintenance strategies and the addition of flavourful and healthy food options to their diet, may help reduce fast-food intake.
Maternal perceptions of their child’s weight status: the GENESIS study
Authors: Manios Yannis , Kondaki Katerina , Kourlaba Georgia , Vasilopoulou Emilia , Grammatikaki Evangelia
Published: December 2008

Objective

The objective of the present work was to quantify mothers’ misclassification of pre-school children’s weight status and to determine factors associated with the maternal misperception.

Design

A representative sample of 2287 children aged 2–5 years was examined (GENESIS study). Mothers’ perceptions of their child’s weight status and the children’s and mothers’ anthropometric and other characteristics (sociodemographic and lifestyle) were recorded.

Results

Almost 38 % of mothers underestimated their child’s weight status. The frequency of underestimation was much higher among ‘at risk of being overweight’ and ‘overweight’ children (88·3 % and 54·5 %, respectively) compared with ‘underweight/normal-weight’ children (18·0 %,P< 0·001). Multiple logistic regression modelling revealed that the likelihood of mothers’ underestimation of their child’s weight status was significantly higher in boys, in children engaging in physical activity for less than 3 h/week and in children whose mothers had low education status, compared with their counterparts. Moreover, the higher the BMI-for-ageZ-score, the greater the odds that the mother would underestimate her child’s weight status.

Conclusions

The current study demonstrated that more than one-third of mothers misclassify their children’s weight status as being lower than the actual. Given that mother’s weight perception might be an important determinant of child’s body weight development, clinicians and health professionals should help mothers correctly classify their children’s weight status, which could potentially help in the early prevention of overweight and obesity.
Jupiter – friend or foe? II: the Centaurs
Authors: Horner J. , Jones B.W.
Published: December 2008

It has long been assumed that the planet Jupiter acts as a giant shield, significantly lowering the impact rate of minor bodies upon the Earth, and thus enabling the development and evolution of life in a collisional environment which is not overly hostile. In other words, it is thought that, thanks to Jupiter, mass extinctions have been sufficiently infrequent that the biosphere has been able to diversify and prosper. However, in the past, little work has been carried out to examine the validity of this idea. In the second of a series of papers, we examine the degree to which the impact risk resulting from objects on Centaur-like orbits is affected by the presence of a giant planet, in an attempt to fully understand the impact regime under which life on Earth has developed. The Centaurs are a population of ice-rich bodies which move on dynamically unstable orbits in the outer Solar system. The largest Centaurs known are several hundred kilometres in diameter, and it is certain that a great number of kilometre or sub-kilometre sized Centaurs still await discovery. These objects move on orbits which bring them closer to the Sun than Neptune, although they remain beyond the orbit of Jupiter at all times, and have their origins in the vast reservoir of debris known as the Edgeworth–Kuiper belt that extends beyond Neptune. Over time, the giant planets perturb the Centaurs, sending a significant fraction into the inner Solar System where they become visible as short-period comets. In this work, we obtain results which show that the presence of a giant planet can act to significantly change the impact rate of short-period comets on the Earth, and that such planets often actually increase the impact flux greatly over that which would be expected were a giant planet not present.
Multiphase magmatic flows at Yucca Mountain, Nevada
Authors: Dartevelle S. , Valentine G. A.
Published: December 2008

The proposed Yucca Mountain radioactive waste repository is sited in southern Nevada in a region that has experienced sporadic basaltic volcanism since the late Miocene. Volcanic risk assessment for the proposed repository requires estimating the consequences of a new monogenetic volcano intersecting the underground facility during its 104–106 year performance period. We report numerical studies aimed at understanding the range of processes and dynamic parameter values that could accompany intersection of an open repository drift by a volatile‐rich trachybasaltic magma as it ascends in a dike. We focus on one end‐member type of magmatic behavior, namely, a fragmented magmatic mixture under pressure interacting with an underground cavity. Initial and boundary conditions are based upon field data and previous modeling studies of the interaction between vertically propagating dikes and a repository opening. The calculations are two‐dimensional and time‐dependent and are conducted with the multiphase hydrodynamics code GMFIX. Calculations indicate that gas‐particle mixtures, as they rise from below and interact with horizontal openings, form complex flow patterns involving varying degrees of recirculation and deposition of pyroclasts. Dynamic pressures are up to 106 Pa but are more typically on the order of 103 to 104 Pa. The geometry and number of outlets play a key role in determining the types of flow patterns, as do volatile contents and the degree of fragmentation. The detailed numerical simulations provide information that will be used to confirm the adequacy of simplified probabilistic consequence models used in risk assessments.
Transport upscaling in heterogeneous aquifers: What physical parameters control memory functions?
Authors: Willmann M. , Carrera J. , Sánchez‐Vila X.
Published: December 2008

Power law tailing is often observed in the breakthrough curves (BTCs) of tracer tests. Tailing is attributed to heterogeneity of aquifer properties and cannot be properly modeled by means of the homogeneous advection‐dispersion equation. Mass transfer models (e.g., continuous time random walk method, multirate mass transfer, or fractional‐order advection‐dispersion equations) using memory have been widely applied for reproducing observed tails. The relationship between memory parameters obtained from BTC fitting and the parameters characterizing the heterogeneity of hydraulic properties is still unclear. Here we investigate the conditions under which heterogeneity produces the type of tailing observed in the field and how memory functions are influenced by measurable heterogeneity parameters (e.g., variance, variogram, or integral scale of the underlying transmissivity field). We find that the slope of a BTC in a log‐log plot is mainly influenced by the connectivity of the underlying permeability field but is insensitive to its variance. The slope BTC reaches asymptotically 2 as connectivity increases. We conclude that an appropriate choice of the memory function allows reproducing the spreading caused by hydraulic heterogeneity but not necessarily the rate of mixing.
HDO and H2O vertical distributions and isotopic ratio in the Venus mesosphere by Solar Occultation at Infrared spectrometer on board Venus Express
Authors: Fedorova A. , Korablev O. , Vandaele A.‐C. , Bertaux J.‐L. , Belyaev D. , Mahieux A. , Neefs E. , Wilquet W. V. , Drummond R. , Montmessin F. , Villard E.
Published: December 2008

Vertical distributions of the molecular density and mixing ratios of H2O and HDO in the Venus mesosphere have been obtained using Solar Occultation at Infrared (SOIR), a high‐resolution (with λ/δλ ∼ 20,000) echelle spectrometer on Venus Express. The atmosphere is sounded in solar occultation in the range of altitudes from 65 to 130 km. Simultaneous measurements of water vapor lines in the spectral range around 2.61 μm (3830 cm−1) at altitudes between 70 and 110 km and HDO lines around 3.58 μm (2715cm−1) at altitudes 70–95 km have been performed. During 1 1/2 years, from April 2006 to August 2007, 54 such measurements have been carried out at different locations of Venus from the north pole to middle south latitudes. Most of the observations at morning and evening terminator correspond to high northern latitudes. We report values of mixing ratio and isotopic ratio obtained for 22 of those measurements occurring in the northern polar area. The average value of the volume mixing ratio of H2O is 1.16 ± 0.24 ppm and that of HDO is 0.086 ± 0.020 ppm. A depletion in the mixing ratio for both H2O and HDO is observed at 85 km, which can be related to a depletion of CO2 density above (∼95 km) and a possible temperature inversion at these altitudes. The vertical variation of HDO and H2O mixing ratio is within a factor of 2–3 for the analyzed set of observations. The temporal variations have been investigated, and no noticeable variability of H2O is reported at high northern altitudes. The average ratio of HDO/H2O obtained in this work, 240 ± 25 times the terrestrial ratio, is higher (≈1.5 times) than the value of 157 ± 30 times terrestrial reported for the lower atmosphere. This could be explained by a lower photodissociation of HDO and/or a lower escape rate of D atoms versus H atoms.
Forecasting Solar Cycle 24 using the relationship between cycle length and maximum sunspot number
Authors: Watari S.
Published: December 2008

The parameters characterizing a solar cycle are its length and its maximum sunspot number. There is a good negative correlation (correlation coefficient is −0.661) between the length of a solar cycle and the maximum monthly smoothed sunspot number of the next cycle. This suggests that the length is an important parameter in determining the variations of solar activity. Using this relationship, I forecast lower solar activity in Cycle 24 than in Cycle 23.
A traffic signal for heterodimeric amino acid transporters to transfer from the ER to the Golgi
Authors: Ganapathy Vadivel
Published: December 2008

Heterodimeric amino acid transporters represent a unique class of transport systems that consist of a light chain that serves as the ‘transporter proper’ and a heavy chain that is necessary for targeting the complex to the plasma membrane. The currently prevailing paradigm assigns no role for the light chains in the cellular processing of these transporters. In this issue of the Biochemical Journal, Sakamoto et al. provide evidence contrary to this paradigm. Their studies with the rBAT –b0,+AT (related to b0,+ amino acid transporter–b0,+-type amino acid transporter) heterodimeric amino acid transporter show that the C-terminus of the light chain b0,+AT contains a sequence motif that serves as the traffic signal for the transfer of the heterodimeric complex from the endoplasmic reticulum to the Golgi. This is a novel function for the light chain in addition to its already established role as the subunit responsible for the transport activity. These new findings also seem to be applicable to other heterodimeric amino acid transporters as well.
Binary-collision-induced longitudinal relaxation in gas-phase Kr83
Authors: Cleveland Zackary I. , Meersmann Thomas
Published: December 2008

Density dependent NMR relaxation measurements of noble gases can provide complementary information to that obtained from relaxation studies of molecular gases. However, conventional noble gas NMR is typically hindered by low sensitivity or prohibitively long relaxation times. In this work, the low sensitivity of Kr83 (I=9∕2) was overcome by spin exchange optical pumping, and the quadrupolar interaction dominated Kr83 T1 times of 40–400s enabled rapid collection of relaxation data. The density dependence of the Kr83 longitudinal relaxation in pure krypton was found to be about 1.6×10−3amagat−1s−1. Experiments were also performed in krypton mixtures containing either helium or nitrogen as a buffer gas. By varying the composition and the density of these mixtures, the density dependence of buffer gas induced relaxation and the relaxation efficiency of Kr83-buffer gas collisions were determined. The results from these gas mixtures are compared with those from pure krypton.
About the ergodic regime in the analogical Hopfield neural networks: Moments of the partition function
Authors: Barra Adriano , Guerra Francesco
Published: December 2008

In this paper we introduce and exploit the real replica approach for a minimal generalization of the Hopfield model by assuming the learned patterns to be distributed according to a standard unit Gaussian. We consider the high storage case, when the number of patterns linearly diverges with the number of neurons. We study the infinite volume behavior of the normalized momenta of the partition function. We find a region in the parameter space where the free energy density in the infinite volume limit self-averages around its annealed approximation, as well as the entropy and the internal energy density. Moreover, we evaluate the corrections to their extensive counterparts with respect to their annealed expressions. The fluctuations of properly introduced overlaps, which act as order parameters, are also discussed.
Near-field modal microscopy of subwavelength light confinement in multimode silicon slot waveguides
Authors: Foubert Kevin , Lalouat Loïc , Cluzel Benoît , Picard Emmanuel , Peyrade David , Delamadeleine Eric , de Fornel Frédérique , Hadji Emmanuel
Published: December 2008

Silicon-on-insulator slot waveguides are studied by scanning near-field optical microscopy. Images of the standing wave pattern were established experimentally and compared with numerical simulations. Fourier analysis along the propagation direction reveals noticeable frequencies both on the experiment and the computation that could be related not only to the guided mode but also to beating phenomena between the coupled waveguides. Finally, light confinement above the slot is directly visualized with a subwavelength resolution and is compared with the expected field distribution.
Interaction of NO(A Σ2+) with rare gas atoms: Potential energy surfaces and spectroscopy
Authors: Kłos Jacek , Alexander Millard H. , Hernández-Lamoneda Ramón , Wright Timothy G.
Published: December 2008

We present the results of an ab initio study of the interaction of electronically excited NO(A Σ2+) with rare gas (Rg) atoms. The bound states of each NO(A)–Rg species are determined from potential energy surfaces calculated at the RCCSD(T) level of theory. Making use of the NO(X 2Π)–Rg vibrational wavefunctions, we then simulate electronic spectra. For NO–Kr and NO–Xe we obtain good qualitative agreement with the previously published experimental spectra. For NO–Ar, the shallowness of the surface gives rise to agreement that is less satisfactory, but a global scaling provides better qualitative agreement. The assignment of the spectra is far from straightforward and is only possible with guidance from the calculated energies and wavefunctions of the energy levels of the complex. Previous assignments are discussed in the light of this conclusion.
Uranyl interaction with the hydrated (001) basal face of gibbsite: A combined theoretical and spectroscopic study
Authors: Veilly Edouard , Roques Jérôme , Jodin-Caumon Marie-Camille , Humbert Bernard , Drot Romuald , Simoni Eric
Published: December 2008

The sorption of uranyl cations and water molecules on the basal (001) face of gibbsite was studied by combining vibrational and fluorescence spectroscopies together with density functional theory (DFT) computations. Both the calculated and experimental values of O–H bond lengths for the gibbsite bulk are in good agreement. In the second part, water sorption with this surface was studied to take into account the influence of hydration with respect to the uranyl adsorption. The computed water configurations agreed with previously published molecular dynamics studies. The uranyl adsorption in acidic media was followed by time-resolved laser-induced fluorescence spectroscopy and Raman spectrometry measurements. The existence of only one kind of adsorption site for the uranyl cation was then indicated in good agreement with the DFT calculations. The computation of the uranyl adsorption has been performed by means of a bidentate interaction with two surface oxygen atoms. The optimized structures displayed strong hydrogen bonds between the surface and the -yl oxygen of uranyl. The uranium-surface bond strength depends on the protonation state of the surface oxygen atoms. The calculated U–Osurface bond lengths range between 2.1–2.2 and 2.6–2.7 Å for the nonprotonated and protonated surface O atoms, respectively.
Tuning magnetic frustration of nanomagnets in triangular-lattice geometry
Authors: Ke Xianglin , Li Jie , Zhang Sheng , Nisoli Cristiano , Crespi Vincent H. , Schiffer Peter
Published: December 2008

We study the configuration of magnetic moments on triangular lattices of single-domain ferromagnetic islands, examining the consequences of magnetostatic interactions in this frustrated geometry. By varying the island-island distance along one direction, we are able to tune the ratios of different interactions between neighboring islands, resulting in a corresponding variation in the local correlations between the island moments. Unlike other artificial frustrated magnets, this lattice geometry displays regions of ordered moment orientation, possibly resulting from a higher degree of anisotropy leading to a reduced level of frustration.
Extended negative glow and “hollow anode” discharges for submillimeter-wave observation of CN−, C2H−, and C4H−
Authors: Amano T.
Published: December 2008

Three molecular anions, CN−, C2H−, and C4H−, have been detected in an extended negative glow discharge and a “hollow anode” discharge in the submillimeter-wave region. These electrical discharges have been unexpectedly found to be reasonable anion sources. The measurements have been extended up to 830 GHz, and the molecular constants have been improved significantly compared with those determined by microwave and millimeter-wave spectroscopy. The parent gas mixture of C2N2 or C2H2 of 2 mTorr and Ar or Ne buffer of 15 mTorr was used for the production of CN− or C2H− and C4H−. The number densities of the anions in the cell were estimated to be ∼1×109, ∼3×107, and ∼3×106 cm−3 for CN−, C2H−, and C4H−, respectively.
Direct evidence of spin-polarized band structure of Sb(111) surface
Authors: Kadono T. , Miyamoto K. , Nishimura R. , Kanomaru K. , Qiao S. , Shimada K. , Namatame H. , Kimura A. , Taniguchi M.
Published: December 2008

We have directly characterized the spin-polarized energy-band structures of Sb(111) near the Fermi level by spin- and angle-resolved photoemission spectroscopy. The results clearly indicate that the energy bands are spin-split due to the spin-orbit coupling and the broken space inversion symmetry.
Enhanced stimulated Raman scattering in silicon nanocrystals embedded in silicon-rich nitride/silicon superlattice structures
Authors: Sirleto L. , Ferrara M. A. , Rendina I. , Basu S. N. , Warga J. , Li R. , Dal Negro L.
Published: December 2008

In this paper, we report on the observation of stimulated Raman scattering in amorphous silicon nanocrystals embedded in Si-rich nitride/silicon superlattice structures (SRN/Si-SLs). In particular, we have experimentally demonstrated amplification of Stokes signal up to 0.9dB∕cm at 1540.6nm using a 1427nm continuous-wavelength pump laser, consistent with a preliminary valuation of approximately a fourfold enhancement of the gain coefficient in Raman amplifier based on SRN/Si-SLs with respect to silicon. Finally, a significant reduction in threshold power of about 40% is also reported. Our findings indicate that silicon nanocrystals embedded in Si nitride-based superlattice structures show great promise for Si-based Raman lasers.
Effect of misfit strain on the multiferroism and nonlinear optical response in epitaxial PbVO3 thin films
Authors: Ju Sheng , Cai Tian-Yi
Published: December 2008

Based on density functional theory (the generalized gradient approximation plus on-site Coulomb repulsion method), we investigate the misfit strain dependence of multiferroism and second-harmonic generation (SHG) in epitaxial PbVO3 thin films. G-type antiferromagnetic ordering, large polar distortion, and significant SHG susceptibilities are revealed in PbVO3 over a wide range of substrates. In particular, the low frequency SHG susceptibility reaches as high as 300×10−9 esu in all the cases we considered, providing solid evidence of its potential application in nonlinear optoelectronic device.
Reduced carrier backscattering in heterojunction SiGe nanowire channels
Authors: Jiang Y. , Singh N. , Liow T. Y. , Lo G. Q. , Chan D. S. H. , Kwong D. L.
Published: December 2008

In this work, we investigate the effect of energy band profile modulation on carrier backscattering in SiGe nanowire (SGNW) heterojunction p-channel field effect transistors. The energy band profile is modulated by increasing the Ge mole fraction in nanowire channels as compared to source/drain regions using the pattern-dependent Ge condensation technique. The carrier backscattering characteristics of the fabricated heterojunction p-type SGNW transistors, extracted using a temperature-dependent analytical model, exhibited a decrease of 19% in hole backscattering coefficient in comparison to the reference planar devices with uniform Ge concentration. The reduction in backscattering coefficient is attributed to KT/q barrier layer thinning of the source-to-channel barrier for the holes as a result of the modulation in energy band profile caused by variation in Ge concentration.
X-ray absorption and magnetic circular dichroism characterization of a novel ferromagnetic MnNx phase in Mn/Si3N4 multilayers
Authors: Céspedes E. , Huttel Y. , Martínez L. , de Andrés A. , Chaboy J. , Vila M. , Telling N. D. , van der Laan G. , Prieto C.
Published: December 2008

Ferromagnetism above room temperature has been observed in Mn/Si3N4 multilayered films for the first time. Characterization of the structural and electronic properties was performed to study the ferromagnetic behavior of this system. X-ray absorption spectroscopy at the Mn K and L edges, as well as x-ray magnetic circular dichroism, evidences the presence of divalent Mn in the films. X-ray absorption near edge structure measurements, which are compared to calculations, confirms the presence of a slightly distorted Mn3N2 phase that is proposed to be the origin of the ferromagnetism in this system.
Cutting down the forest of peaks in acoustic dynamic atomic force microscopy in liquid
Authors: Carrasco C. , Ares P. , de Pablo P. J. , Gómez-Herrero J.
Published: December 2008

Acoustic dynamic force microscopy in liquids is a fundamental technique for the investigation of biological samples under physiological conditions. However, it shows an important drawback that consists of producing a myriad of resonance peaks, known as the forest of peaks, which hides the natural resonance frequency of the cantilever and prevents an optimum operation of the microscope. In this work, we propose a simple remedy for this problem, which consists on adding a small clay damper to the dither piezoelectric. The resulting frequency spectrum exhibits a single resonance peak that is comparable with the one obtained using magnetic excitation.
A p-n homojunction ZnO nanorod light-emitting diode formed by As ion implantation
Authors: Yang Y. , Sun X. W. , Tay B. K. , You G. F. , Tan S. T. , Teo K. L.
Published: December 2008

We report stable and repeatable UV and red electroluminescence (EL) from ZnO nanorod (NR) array light-emitting diodes (LEDs), where the p-type ZnO was formed by As+ ion implantation into the as-grown ZnO NRs. Both doped and undoped single ZnO NRs were probed using nanomanipulator, where the former ones showed good rectification characteristics, confirming the formation of p-n homojunctions by ion implantation. Distinct EL emissions in UV and red regions were observed at room temperature under forward bias, where the emission intensity shows amplified spontaneous emission characteristics, suggesting high efficiency of these LEDs.
Transformation-optical design of sharp waveguide bends and corners
Authors: Roberts D. A. , Rahm M. , Pendry J. B. , Smith D. R.
Published: December 2008

Transformation optics is a recently appreciated approach for designing complex electromagnetic media. Here, we describe the extension of transformation optical techniques to include waveguide boundary conditions. We illustrate the use of finite embedded coordinate transformations to design a medium that can be incorporated into a waveguide bend or corner, rendering the structure reflectionless. The expected behavior of the waveguide bends is confirmed with numerical simulations.
Elastic, dielectric, and piezoelectric properties of BaTeMo2O9 single crystal
Authors: Gao Zeliang , Tao Xutang , Yin Xin , Zhang Weiguo , Jiang Minhua
Published: December 2008

Ba Te Mo 2 O 9 is a noncentrosymmetric single crystal for nonlinear optical applications. In this letter, we report complete set of elastic, dielectric, and piezoelectric constants of BaTeMo2O9 single crystal determined by resonance technique and impedance analysis, the relative constants have been obtained and discussed. Our results show that BaTeMo2O9 crystal has excellent piezoelectric property (d34=30.25pC∕N, s44=36.46pm2∕N) and could be a promising candidate for piezoelectric applications.
Ultrafast nonlinearities and gain dynamics in high-power semiconductor amplifiers
Authors: Motamedi Ali R. , Plant Jason J. , Donnelly Joseph P. , Juodawlkis Paul W. , Ippen Erich P.
Published: December 2008

The limits imposed by two-photon absorption and free-carrier absorption on the gain and output powers of an InGaAsP∕InP slab-coupled optical waveguide amplifier with a confinement factor of Γ=0.5% were studied. The two-photon absorption coefficient and the induced free-carrier absorption cross section were measured to be 65cm∕GW and 7×10−17cm2, respectively. The effects of two-photon absorption begin to limit the gain significantly for pulses shorter than 40ps. The carrier recovery times were observed to vary between 390 and 160ps for 1–4A bias currents, and the short-pulse saturation fluence of the gain was determined to be 1.4mJ∕cm2.
Mice lacking asparaginyl endopeptidase develop disorders resembling hemophagocytic syndrome
Authors: Chan Chi-Bun , Abe Michiyo , Hashimoto Noriyoshi , Hao Chunhai , Williams Ifor R. , Liu Xia , Nakao Shinji , Yamamoto Akitsugu , Zheng Chengyun , Henter Jan-Inge , Meeths Marie , Nordenskjold Magnus , Li Shi-Yong , Hara-Nishimura Ikuko , Asano Masahide , Ye Keqiang
Published: December 2008

Asparaginyl endopeptidase (AEP or legumain) is a lysosomal cysteine protease that cleaves protein substrates on the C-terminal side of asparagine. AEP plays a pivotal role in the endosome/lysosomal degradation system and is implicated in antigen processing. The processing of the lysosomal proteases cathepsins in kidney is completely defective in AEP-deficient mice with accumulation of macromolecules in the lysosomes, which is typically seen in lysosomal disorders. Here we show that mutant mice lacking AEP develop fever, cytopenia, hepatosplenomegaly, and hemophagocytosis, which are primary pathological manifestations of hemophagocytic syndrome/hemophagocytic lymphohistiocytosis (HLH). Moreover, AEP deficiency provokes extramedullary hematopoiesis in the spleen and abnormally enlarged histiocytes with ingested red blood cells (RBCs) in bone marrow. Interestingly, RBCs from AEP-null mice are defective in plasma membrane components. Further, AEP-null mice display lower natural killer cell activity, but none of the major cytokines is substantially abnormal. These results indicate that AEP might be a previously unrecognized component in HLH pathophysiology.
The interaction of metonymy and metaphor in the meaning and form of ‘bahuvrihi’ compounds
Authors: Barcelona Antonio
Published: December 2008

This paper reports on ongoing work on a large sample of bahuvrihi compounds in English and Spanish. After a brief characterization of bahuvrihi compounds, distinguishing them from a similar type of exocentric compounds (V+O compounds), the goal of the paper is clearly stated, namely to answer a number of questions, especially these two: (a) Does the metonymy CHARACTERISTIC PROPERTY FOR CATEGORY motivate the exocentric nature of all the compounds in the sample?; (b) Are other metonymies or metaphors also involved? If so, which are the metonymic or metaphoric patterns observable in conceptualizations underlying these compounds? The bulk of the paper is devoted to the detailed conceptual analysis of a large set of representative bahuvrihis in both languages. The results show that the above metonymy is responsible for the exocentric nature of all the compounds in the sample and that the characteristic property mapped by that metonymy is conceptualized in one of these three ways: literally, metonymically or metaphorico-metonymically. These three conceptualization patterns constitute the three major types of bahuvrihis in both languages; various further subtypes are proposed for each type. The paper ends with some tentative remarks on the Cognitive Grammar representation of the semantic structure of these compounds, on the connection between their semantic structure and their grammar and prosody, on a blending account of these lexemes, and on the contrasts identified between both languages.
La investigación del español del Suroeste
Authors: Marcos-Marín Francisco
Published: December 2008

This is the second of two articles dealing with the epistemology of the analysis of Spanish in the Southwest of the United States of America. The content of this part is basically linguistic, with social implications, and mostly synchronic. The historical references, however, are never set aside. In the first place, it is important to make a distinction between the real melting languages and theoretical misinterpretations. English and Spanish are combined with social and literary implications in the diverse slang forms of the area: pachuco, caló, among others. Spurious interests, however, have given force to fantastic hypotheses brought to a climax by the invention of an allegedly “new” language, called Spanglish. This lexical choice is unfortunate, because it takes advantage of the existence of a more innocuous use of the word, simply referring to all forms of contact between the two languages. Four aspects are therefore mixed up and mistaken: the invention of an allegedly “new” language, in spite of a total lack of unification; the constant code-switching with different modalities and extent; the bad quality of certain translations; and the cultural relegation of Hispanics to speakers of a ghetto language. The set of two articles ends with a graphical presentation of a SWOT analysis (strengths, weaknesses, opportunities and threats). The conclusion refers to Judeo-Spanish and the dangers of ghetto languages, as well as to the role of education.
“International” forms of Biblical Hebrew personal names
Authors: Sadan Tsvi
Published: December 2008

The present study attempts to examine what presumably guided Zamenhof in choosing “international” forms for Biblical Hebrew personal names when he translated the whole Hebrew Bible into Esperanto. A comparison of these names graphically and phonetically with their equivalents in eight possible source languages, i.e., Hebrew, Latin, Italian, French, English, German, Polish and Russian, reveals a preference for Hebrew, German and Polish forms in descending order as possible etymons ascribable to Zamenhof’s own linguistic background. The morphological adaptation of these names is conditioned by the phonetic characteristics of their etymons.
Interlinguistics and Esperanto studies at universities
Authors: Fiedler Sabine
Published: December 2008

The Bologna process aims to create a European Higher Education Area by 2010, in which university studies are comparable and compatible and degrees more transparent. Its priority is the introduction of the three-cycle system Bachelor — Master — Doctorate. At the University of Leipzig a project was launched to connect the implementation of the new structures with the establishment of a programme in interlinguistics and Esperanto studies. In the winter semester 2007/2008 a compulsory-optional module with the title Universal Languages was taught, consisting of a weekly lecture, seminar and a language course Esperanto. It was an initiative of the Gesellschaft für Interlinguistik e.V. and financially supported by the Esperantic Studies Foundation. The paper reports on the structure, contents and results of the module and draws conclusions for similar initiatives at other European universities.
Une analyse méthodique pour l’extraction terminologique dans le domaine du nucléaire
Authors: Calberg-Challot Marie , Candel Danielle , Bourigault Didier , Dumont Xavier , Humbley John , Joseph Jacques
Published: December 2008

This article describes an evaluation of the Syntex tool used to define a terminology reference frame base for building a new dictionary. This tool is then used in an experiment in which technical terms are extracted from different corpora. These terms belong to the sub-domains “Fuel” and “Reactors” in the nuclear engineering field. The strategy used to exploit the results is explained and the terms extracted are analyzed. This method consists in submitting the results to nuclear field experts and combining their conclusions with terminological assessments. This article illustrates how these kinds of specialized contributions can be effectively employed. It is also shown how this orginal procedure can be generalized to other sub-domains in nuclear engineering.
Lotus japonicusCASTOR and POLLUX Are Ion Channels Essential for Perinuclear Calcium Spiking in Legume Root Endosymbiosis
Authors: Charpentier Myriam , Bredemeier Rolf , Wanner Gerhard , Takeda Naoya , Schleiff Enrico , Parniske Martin
Published: December 2008

The mechanism underlying perinuclear calcium spiking induced during legume root endosymbioses is largely unknown. Lotus japonicus symbiosis-defective castor and pollux mutants are impaired in perinuclear calcium spiking. Homology modeling suggested that the related proteins CASTOR and POLLUX might be ion channels. Here, we show that CASTOR and POLLUX form two independent homocomplexes in planta. CASTOR reconstituted in planar lipid bilayers exhibited ion channel activity, and the channel characteristics were altered in a symbiosis-defective mutant carrying an amino acid replacement close to the selectivity filter. Permeability ratio determination and competition experiments reveled a weak preference of CASTOR for cations such as potassium over anions. POLLUX has an identical selectivity filter region and complemented a potassium transport–deficient yeast mutant, suggesting that POLLUX is also a potassium-permeable channel. Immunogold labeling localized the endogenous CASTOR protein to the nuclear envelope of Lotus root cells. Our data are consistent with a role of CASTOR and POLLUX in modulating the nuclear envelope membrane potential. They could either trigger the opening of calcium release channels or compensate the charge release during the calcium efflux as counter ion channels.
Anthropology and Environment Section
Authors: Ogden Laura
Published: December 2008

•In Defense of Functionalism James Holland Jones, Rebecca Bliege Bird
Archeology Division
Authors: Alexander Rani T
Published: December 2008

•Barbara Voss Wins 2008 Gordon R Willey Award Ben Nelson
Association for Africanist Anthropology
Authors: Coffman Jennifer E
Published: December 2008

•AfAA at the 2008 AAA Meeting Bennetta Jules‐Rosette  •AfAA Invited Sessions in San Francisco Maria Cattell, David
Culture and Agriculture
Authors: Rich Ronald
Published: December 2008

•Task Force on World Food Problems Louise Sperling, Shawn McGuire