bluuebunny/crossref_metadata_2025 huggingface dataset:
AGU education and public outreach programs: Empowering future Earth and space scientists
Authors: Adamec Bethany , Asher Pranoti
Published: October 2011

The staff and leadership of AGU are committed to fostering excellence in Earth and space science education. While AGU's Strategic Plan does not specifically highlight primary or secondary education among its objectives, outreach in this area plays a significant role in developing and nurturing the next generation of Earth and space scientists. Several educational goals along with specific strategies will help AGU meet its goal related to workforce or talent pool development. Particular emphasis is being placed on building partnerships and collaborations that will increase the effectiveness of AGU's outreach efforts related to education.
Potential solution to the cool tropics paradox
Authors: Schultz Colin
Published: October 2011

The “cool tropics paradox” has been a thorn in the side of paleoclimate researchers, who draw on diverse techniques to improve their estimates of ancient climates. For the early Paleogene, between approximately 56 million and 49 million years ago, atmospheric reconstructions hint at a world much warmer than present, yet estimates of tropical sea surface temperatures determined by looking at the shells of foraminifera— a type of marine plankton—skew low, falling below present values. Throughout their lives, foramanifera form a calcium carbonate shell that records chemical parameters of the ambient seawater, and analyzing the oxygen isotope ratios in preserved shells is one of the dominant methods of estimating ancient ocean temperatures. Recently, however, researchers have found that posthumous alteration can displace the original biological structures, changing the oxygen isotope ratio and presenting a potential explanation for the source of the cool tropics paradox.
High‐resolution model reproduces heliospheric current sheet fold
Authors: Schultz Colin
Published: October 2011

Spewing from the Sun, magnetic field lines are carried by the solar wind to the outer reaches of the solar system. Crossing over the extended reach of the Sun' equator, these magnetic field lines turn inward toward the Sun's opposite hemisphere. Particularly during solar minimum, the path traced by these magnetic fields creates an equatorially partitioned solar system, with distinct halves of inward and outward polarity. The heliospheric current sheet, a thin region of space with no magnetic polarity and a large electrical current, divides the inward polarity and outward polarity regions.
First map of sea ice production in Arctic coastal polynyas
Authors: Balcerak Ernie
Published: October 2011

In Arctic coastal polynyas, persistent areas of thin ice, a large amount of new ice forms during winters. Significant heat is lost through these regions of thin ice. Knowing how much ice is produced in polynyas is important for determining overall cold saline water formation in the Arctic Ocean. However, because of the difficulty of making in situ measurements, there have been few studies of ice production in coastal Arctic polynyas.
Shrinking Alpine glaciers spell trouble for Europe's rivers
Authors: Schultz Colin
Published: October 2011

Within the frosted peaks of the Swiss Alps, the cycle of winter precipitation accumulation and springtime melt provides a seasonal flow of water to much of western Europe. Research into the freshwater contributions of Alpine glaciers has predominantly looked to measure water released directly from glacier melt. A glacier's overall water storage, however, which takes into account the snow that resides on the glacier's surface, more accurately describes the role Swiss glaciers play in feeding European streams. A new analysis by Huss that investigated the effects of changing Swiss glacier storage on the flows of four of Europe's largest rivers suggests that glaciers may be more important than previously realized.
Examining nitrogen isotope ratios as a paleoproxy
Authors: Balcerak Ernie
Published: October 2011

The relative consumption of nutrients by diatoms in the ocean, with regard to both supply and demand of nitrate, affects the nitrogen isotope composition of diatoms. Sedimentary nitrogen isotope ratios are often used as a proxy for past conditions. However, there are uncertainties associated with these nitrogen isotope proxies. Bulk sediment nitrogen isotope ratios differ from fossil diatom‐bound nitrogen isotope ratios. To learn more about these uncertainties, Horn et al. measured nitrogen isotopes in five different species of cultured diatoms. The results indicate that there are significant interspecies variations in the offsets between isotope ratios in the total biomass and isotope ratios in the diatom‐bound nitrogen. These differences should be considered when interpreting nitrogen isotope ratios. (Paleoceanography, doi:10.1029/2010PA002080, 2011)
Holocene evolution of deep circulation in the northern North Atlantic traced by Sm, Nd and Pb isotopes and bulk sediment mineralogy
Authors: Fagel N. , Mattielli N.
Published: October 2011

Bulk mineralogy, Sm, Nd and Pb elemental and isotopic compositions of the clay‐size fraction of Holocene sediments were analyzed in three deep North Atlantic cores to trace the particle provenance. The aims of the present paper are to identify the origin of the particles driven by deep currents and to reconstruct deep circulation changes over the Holocene in the North Atlantic. The three cores are retrieved in fracture zones; two of them are located in the Island Basin along the gyre of North Atlantic Deep Water, and the third core is located off the present deep circulation gyre in the Labrador Sea. Whereas sedimentary supplies in the Labrador Sea were constantly derived from proximal sources, the geochemical mixing trends in the Iceland Basin samples indicate pronounced changes in the relative contribution of continental margin inputs over the past 6 kyr. Supplies from western European margin that sharply increased at 6 kyr were progressively diluted by a larger contribution of Scandinavian margins over the last 3 kyr. Changes in composition of the particles imply significant reorganization of paleocirculation of the deep North Atlantic components in the eastern basins: mainly reorganizations for both Iceland‐Scotland Overflow Water and Norwegian Sea Overflow Water. Moreover the unusual Pb isotopic composition of the oldest sediments from the southern Iceland Basin indicates that distal supplies from Greenland margin were driven into the Iceland Basin, supporting a deep connection between Labrador Sea and Iceland Basin through the Charlie Gibbs Fracture Zone prior the Holocene Transition period.
Structure–activity relationships of methyl-lysine reader antagonists
Authors: Herold J. Martin , James Lindsey Ingerman , Korboukh Victoria K. , Gao Cen , Coil Kaitlyn E. , Bua Dennis J. , Norris Jacqueline L. , Kireev Dmitri B. , Brown Peter J. , Jin Jian , Janzen William P. , Gozani Or , Frye Stephen V.
Published: October 2011

The structure–activity relationships for small molecule antagonists of the Malignant Brain Tumor (MBT) domain family of methyl-lysine readers are described and activity demonstrated in histone peptide pull-down assays.
Drag reduction of a hairy disk
Authors: Niu Jun , Hu David L.
Published: October 2011

We investigate experimentally the hydrodynamics of a hairy disk immersed in a two-dimensional flowing soap film. Drag force is measured as a function of hair length, density, and coating area. An optimum combination of these parameters yields a drag reduction of 17%, which confirms previous numerical predictions (15%). Flow visualization indicates the primary mechanism for drag reduction is the bending, adhesion, and reinforcement of hairs trailing the disk, which reduces wake width and traps “dead water.” Thus, the use of hairy coatings can substantially reduce an object’s drag while negligibly increasing its weight.
Single crystal nuclear magnetic resonance in spinning powders
Authors: Pell Andrew J. , Pintacuda Guido , Emsley Lyndon
Published: October 2011

We present a method for selectively exciting nuclear magnetic resonances (NMRs) from well-defined subsets of crystallites from a powdered sample under magic angle spinning. Magic angle spinning induces a time dependence in the anisotropic interactions, which results in a time variation of the resonance frequencies which is different for different crystallite orientations. The proposed method exploits this by applying selective pulses, which we refer to as XS (for crystallite-selective) pulses, that follow the resonance frequencies of nuclear species within particular crystallites, resulting in the induced flip angle being orientation dependent. By selecting the radiofrequency field to deliver a 180 ○ pulse for the target orientation and employing a train of such pulses combined with cogwheel phase cycling, we obtain a high degree of orientational selectivity with the resulting spectrum containing only contributions from orientations close to the target. Typically, this leads to the selection of between 0.1% and 10% of the crystallites, and in extreme cases to the excitation of a single orientation resulting in single crystal spectra of spinning powders. Two formulations of this method are described and demonstrated with experimental examples on [1 − 13C]-alanine and the paramagnetic compound Sm2Sn2O7.
Photoelectron-photofragment coincidence spectroscopy in a cryogenically cooled linear electrostatic ion beam trap
Authors: Johnson Christopher J. , Shen Ben B. , Poad Berwyck L. J. , Continetti Robert E.
Published: October 2011

A cryogenically cooled linear electrostatic ion beam trap for use in photoelectron-photofragment coincidence (PPC) spectroscopy is described. Using this instrument, anions created in cold, low-duty-cycle sources can be stored for many seconds in a ∼20 K environment to cool radiatively, removing energetic uncertainties due to vibrationally excited precursor anions. This apparatus maintains a well-collimated beam necessary for high-resolution fragment imaging and the high experimental duty cycle needed for coincidence experiments. Ion oscillation is bunched and phase-locked to a modelocked laser, ensuring temporal overlap between ion bunches and laser pulses and that ions are intersected by the laser only when travelling in one direction. An electron detector is housed in the field-free center of the trap, allowing PPC experiments to be carried out on ions while they are stored and permitting efficient detection of 3-dimensional electron and neutral recoil trajectories. The effects of trapping parameters on the center-of-mass trajectories in the laser-ion interaction region are explored to optimize neutral particle resolution, and the impact of bunching on ion oscillation is established. Finally, an initial demonstration of radiative cooling is presented.
Theory and simulation of diffusion-influenced, stochastically gated ligand binding to buried sites
Authors: Barreda Jorge L. , Zhou Huan-Xiang
Published: October 2011

We consider the diffusion-influenced rate coefficient of ligand binding to a site located in a deep pocket on a protein; the binding pocket is flexible and can reorganize in response to ligand entrance. We extend to this flexible protein-ligand system a formalism developed previously [A. M. Berezhkovskii, A, Szabo, and H.-X. Zhou, J. Chem. Phys. 135, 075103 (2011)10.1063/1.3609973] for breaking the ligand-binding problem into an exterior problem and an interior problem. Conformational fluctuations of a bottleneck or a lid and the binding site are modeled as stochastic gating. We present analytical and Brownian dynamics simulation results for the case of a cylindrical pocket containing a binding site at the bottom. Induced switch, whereby the conformation of the protein adapts to the incoming ligand, leads to considerable rate enhancement.
Controlling flow patterns in oscillating sessile drops by breaking azimuthal symmetry
Authors: Mampallil Dileep , van den Ende Dirk , Mugele Frieder
Published: October 2011

We study time-averaged flows within sessile drops that oscillate under the influence of an AC voltage applied in electrowetting configuration. We show that the average flow velocity in the azimuthal plane correlates with the eigenmodes of the drop in the polar direction and—most importantly—we demonstrate that the azimuthal symmetry of the flow fields can be broken by introducing pinning sites along the contact line of the drop. We anticipate that the controlled introduction of azimuthal vortices increases the mixing efficiency inside the droplet.
Collisional current drive in two interpenetrating plasma jets
Authors: Ryutov D. D. , Kugland N. L. , Park H.-S. , Pollaine S. M. , Remington B. A. , Ross J. S.
Published: October 2011

The magnetic field generation in two interpenetrating, weakly collisional plasma streams produced by intense lasers is considered. The generation mechanism is very similar to the neutral beam injection current drive in toroidal fusion devices, with the differences related to the absence of the initial magnetic field, short interaction time, and different geometry. Spatial and temporal characteristics of the magnetic field produced in two counterstreaming jets are evaluated; it is shown that the magnetic field of order of 1 T can be generated for modest jet parameters. Conditions under which this mechanism dominates that of the “Biermann battery” are discussed. Other settings where the mechanism of the collisional current drive can be important for the generation of seed magnetic fields include astrophysics and interiors of hohlraums.
Improved negative bias illumination instability of sol-gel gallium zinc tin oxide thin film transistors
Authors: Seo Seok-Jun , Hyuck Jeon Jun , Hwan Hwang Young , Bae Byeong-Soo
Published: October 2011

We investigated the Ga doping effect on the performance and negative bias illumination instability of sol-gel zinc tin oxide (ZTO) thin film transistors (TFTs). The performance of the Ga doped ZTO (GZTO) TFTs is controlled and optimized by the concentration of Ga ions, which suppress the formation of oxygen vacancies. The negative bias illumination instability of the devices with a sol-gel hybrid material passivation layer is compared through a time-evolution stress analysis and illumination wavelength dependence measurements. The GZTO TFT exhibits improved stability relative to the ZTO TFT, because Ga ions effectively decrease charge trapping sites originating from oxygen vacancies.
Origin of the giant electro-optic Kerr effect in La-doped 75PMN-25PT transparent ceramics
Authors: Ruan Wei , Li Guorong , Zeng Jiangtao , Kamzina Liudmila S. , Zeng Huarong , Zhao Kunyu , Zheng Liaoying , Ding Aili
Published: October 2011

Transparent ceramics of La-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) x/75/25 are prepared, and the ferroelectric domains, dielectric, and ferroelectric properties of x/75/25 are investigated. A double hysteresis loop and small fingerprint domains with uniform distribution observed for 3/75/25 indicate an intermediate ferroelectric state. The dielectric behavior under dc bias and the evolution of the hysteresis loop with increasing electric field for 3/75/25 indicate an electric field-induced phase transition, and it is proposed that the unstable intermediate ferroelectric state which would experience obvious field-induced phase transition is the origin of the giant electro-optic Kerr effect observed in La-doped PMN-PT 3/75/25.
Electron-vibron coupling in halogenated acenaphthenequinone upon O K-edge soft x-ray absorption
Authors: Schmidt Norman Anja , Clark Tim , Urquhart Stephen G. , Fink Rainer H.
Published: October 2011

We present high resolution oxygen K near-edge x-ray absorption spectra of the acenaphthenequinone (ANQ) derivative 3,8-dibromo-5,6-dichloro-ANQ (Br2Cl2-ANQ). The spectral features exhibit an almost identical vibronic fine structure compared to that shown by ANQ. The unequal distances of the vibronic levels as derived from the least-squares fit analysis of the vibronic progressions allows us to determine the anharmonicity of the excited state potentials involved. We conclude that a single vibrational progression couples to the resonant excitation of O 1s core electrons preferentially. Comparison of the two ANQ derivatives gives a clear indication that the vibronic mode corresponds to a C=O stretching mode, rather than coupling to a C–H mode as suggested previously. These conclusions are supported by density functional theory calculations.
The transition probabilities from the ground state to the excited J = 0 $\sideset{^1}{ _u^+}{\Sigma}$Σu+1 levels of H2: Measurements and ab initio quantum defect study
Authors: Glass-Maujean M. , Jungen Ch. , Schmoranzer H. , Haar I. , Knie A. , Reiss P. , Ehresmann A.
Published: October 2011

The energies, widths and absolute intensities of the P(1) v′′ = 0, J′′ = 1 absorption transitions of H2 have been measured in the spectral range of 81-75 nm using monochromatized synchrotron radiation. This work completes and extends previous observations, in particular those of Herzberg and Jungen [J. Mol. Spectrosc. 41, 425 (1972)]10.1016/0022-2852(72)90064-1. Ab initio multichannel quantum defect theory (MQDT) is used to corroborate the spectral analysis of the experimental data. Line intensities and decay widths are also calculated using MQDT.
Low-loss polymer waveguides on nanoporous layers
Authors: Wicht G. , Ferrini R. , Schüttel S. , Zuppiroli L.
Published: October 2011

Multimode planar polymer waveguides were fabricated on hybrid polymer nanoporous layers with a fast industrial aqueous-based method well adapted to coat large-surface plastic substrates and easily scalable up to economical mass production volumes. Using a fiber probe internal light source technique, we were able to measure quantitatively the modal propagation losses. In particular, attenuation coefficients lower than 0.5 dB/cm were found for the fundamental modes, thus showing the potential of our polymer nanoporous layers as optical isolation layers in waveguiding applications.
Lead-free ternary perovskite compounds with large electromechanical strains
Authors: Jarupoom Parkpoom , Patterson Eric , Gibbons Brady , Rujijanagul Gobwute , Yimnirun Rattikorn , Cann David
Published: October 2011

Lead-free compounds based on perovskite solid solutions in the ternary system (Bi1/2Na1/2)TiO3–(Bi1/2K1/2)TiO3–Bi(X1/2Ti1/2)O3, where X = Ni and Mg have been shown to exhibit large electromechanical strains. While the perovskite end members Bi(Mg1/2Ti1/2)O3 and Bi(Ni1/2Ti1/2)O3 display limited stability in their pure state, both compounds were found to have solid solubilities of at least 50 mol. % with (Bi1/2Na1/2)TiO3 and (Bi1/2K1/2)TiO3. Most importantly, under relatively large applied fields, these materials exhibited large hysteretic electromechanical strains characterized by a parabolic shape. With effective piezoelectric coefficients (d33*) greater than 500 pm/V, these systems have excellent potential as a Pb-free piezoelectric materials.
Total electron emission yield measurement of insulator by a scanning small detector
Authors: Chen Yu , Kouno Takanori , Toyoda Kazuhiro , Cho Mengu
Published: October 2011

Due to the injection of primary electrons and the emission of secondary electrons in the surface layer of insulating materials, the target surface will be negatively or positively charged. A method by injecting a single pulse beam and using a small current detector for the total electron emission yield measurement of insulating material is proposed, which can avoid the influence from charged surface. Using the developed system, the total electron emission yield of 25 μm thick polyimide film has been studied, as induced by a single 50 μs pulse of primary electrons with energy up to 2500 eV.
Toward compact millimeter-wave diode in thin stacked-hole array assisted by a dielectric grating
Authors: Beruete M. , Serebryannikov A. E. , Torres V. , Navarro-Cía M. , Sorolla M.
Published: October 2011

Unidirectional transmission in thin stacked hole arrays (SHAs), whose spatial inversion symmetry is broken by adding a dielectric grating at one of the interfaces, is theoretically predicted and experimentally validated in the millimeter-wave regime. It appears at a fixed nonzero angle of incidence due to hybridization of SHA resonances with diffraction effects. In contrast to the earlier suggested structures with the diffraction relevant unidirectional transmission mechanism, the nonsymmetric diode-like structure founded on the intrinsically subwavelength SHA, which supports left-handed propagation, is less than one wavelength thick.
Photoluminescence and cathodoluminescence from nanostructured silicon surface
Authors: Ranjan Gartia Manas , Chen Yi , Logan Liu Gang
Published: October 2011

We report the photoluminescence (PL) and cathodoluminescence (CL) study of nanostructured poly-crystalline silicon surface fabricated by lithography-less, reactive ion etching process. Photoluminescence in visible range at room temperature with peak position between 630 nm and 720 nm is observed without any oxidation or annealing steps. X-ray photoemission (XPS) and Auger electron spectroscopy (AES) revealed the presence of silicon oxide. The observed cathodoluminescence in green and red regions of the visible spectrum are due to nano-scaled tips and their coating with nonstoichiometric silicon oxide.
Observation of electric-field induced aggregation in crystallizing protein solutions by forward light scattering
Authors: Wakamatsu Takashi , Toyoshima Susumu , Shimizu Hidehiko
Published: October 2011

Protein aggregation has been observed in-situ in lysozyme solutions under an internal electric field using a forward light scattering technique. Light scattering at small forward angles revealed that the application of a low voltage to the protein solutions significantly promotes aggregate formation. The solutions required a specific amount of time exposed to an electric field before the solution had undergone sufficient protein aggregation. The in-situ results from forward light scattering allow the characterization of the process.
Determinant influence of surfaces on the Co clustering trend at ZnO
Authors: Sanchez N. , Gallego S. , Muñoz M. C.
Published: October 2011

Based on ab-initio calculations, we demonstrate that Co tends to cluster at the bulk host favoring [0001] planar structures. However, this tendency is modified at surfaces, involving energy variations an order of magnitude larger than in the bulk. The energy cost to replace Zn by Co, either for isolated impurities or for one- and two-dimensional aggregates, is considerably reduced close to both stoichiometric and polar surfaces, evidencing a tendency of Co impurities to approach the ZnO surface. The formation of Co aggregates strongly depends on the crystallographic termination, leading to the suppression of the Co clustering trend at the O-ended (0001¯).
Quantitative analysis of the trapping effect on terahertz AlGaN/GaN resonant tunneling diode
Authors: Yang Lin’an , He Hanbing , Mao Wei , Hao Yue
Published: October 2011

We report on a simulation for terahertz aluminum gallium nitride (AlGaN)/gallium nitride (GaN) resonant tunneling diode (RTD) at room temperature by introducing deep-level defects into the polarized AlGaN/GaN/AlGaN quantum well. Results show that an evident degradation in negative-differential-resistance characteristic of RTD occurs when the defect density is higher than ∼106 cm−2, which is consistent with the measurements of the state-of-the-art GaN RTDs. At around 300 GHz, the simulation for a RTD oscillator also demonstrates evident decreases of rf power and efficiency because of the electron trapping effect.
Current-induced coupled domain wall motions in a two-nanowire system
Authors: Purnama I. , Chandra Sekhar M. , Goolaup S. , Lew W. S.
Published: October 2011

In two closely spaced nanowires system, where domain walls exist in both of the nanowires, applying spin-polarized current to any of the nanowire will induce domain wall motions in the adjacent nanowire. The zero-current domain wall motion is accommodated by magnetostatic interaction between the domain walls. As the current density is increased, chirality flipping is observed in the adjacent nanowire where no current is applied. When current is applied to both nanowires, the coupled domain wall undergoes oscillatory motion. Coupling breaking is observed at a critical current density which varies in a non-linear manner with respect to the interwire spacing.
Enhanced dc magnetic field sensitivity by improved flux concentration in magnetoelectric laminates
Authors: Gao Junqi , Gray David , Shen Ying , Li Jiefang , Viehland D.
Published: October 2011

In this letter, we present magnetostatic modeling results that show significant magnetic field concentration tunability through geometric modification of high-mu magnetostatic Metglas layers of laminate magnetoelectric (ME) sensors. Based on the modeling results, composite ME sensors were fabricated with longer Metglas foils and found to exhibit notably higher ME voltage coefficients at smaller DC magnetic biases in response to a 1 kHz driving signal. Such ME sensors have been used to detect DC magnetic field changes as small as 6 nT at 1 kHz, while maintaining a signal-to-noise ratio greater than 10. This represents an enhancement of ∼250% relative to values previously reported for Metglas/Pb(Zr,Ti)O3 laminates.
Optical breakdown of air triggered by femtosecond laser filaments
Authors: Polynkin Pavel , Moloney Jerome V.
Published: October 2011

We report experiments on the generation of dense plasma channels in ambient air using a dual laser pulse excitation scheme. The dilute plasma produced through the filamentation of an ultraintense femtosecond laser pulse is densified via avalanche ionization driven by a co-propagating multi-Joule nanosecond pulse.
Theoretical analysis of the formation of face-centered cubic Si nanocrystals by magnetron sputtering
Authors: Hu Shengliang , Zhang Jingqi , Yang Jinlong , Liu Jun , Cao Shirui
Published: October 2011

To have a clear insight into the physical origin of the nucleation of face-centered cubic Si in the magnetron sputtering condition, a theoretical model was proposed by taking the capillary effect of the nanosized curvatures of the critical nucleus and the concave surface on the substrate into account. The calculation shows that the size and energy of the critical nucleation depend on the radius of the concave surface on the substrate and the temperature. Both the smaller radius of concave surface and the higher temperature are propitious to the formation of face-centered cubic Si nanocrystals.
The post-fire response of an obligate seeding Triodia species (Poaceae) in the fire-prone Kimberley, north-west Australia
Authors: Armstrong Graeme , Legge Sarah
Published: October 2011

Triodia spp. have been described as behaving functionally as a shrub because above ground biomass accumulates slowly over time culminating as the dominant vegetation layer. When combined with high flammability, little seed dormancy and conflicting evidence for fire induced seed germination, obligate seeding species may be more vulnerable to short fire intervals than resprouting species. This study investigated the post-fire regeneration response of the obligate seeder Triodia sp. nov. (aff. T. schinzii Henrard) in the fire prone Kimberley, Western Australia. Adult plants were destroyed by fire in experimental plots to assess the degree of regeneration from either resprouting or germination from seed due to fire. To control for the removal of adults, without fire, plants were pulled out by hand in replicate plots. Germination of Triodia sp. nov. seed from the soil seed bank was strongly induced by fire. Establishment and survival of seedlings through the first dry season was high with a small proportion of individuals flowering at this time. It is concluded that Triodia sp. nov. is resilient to the short fire intervals experienced in the Kimberley where it is a successful localised species.
Genetic differentiation and introgression amongst Thylogale (pademelons) taxa in eastern Australia
Authors: Eldridge M. D. B. , Heckenberg K. , Neaves L. E. , Metcalfe C. J. , Hamilton S. , Johnson P. M. , Close R. L.
Published: October 2011

Although pademelons (Thylogale) are widespread and common in coastal eastern Australia, they have been largely neglected in population genetic studies. Here we use 10 microsatellite loci and the mitochondrial DNA (mtDNA) cytochrome b (Cytb) gene to examine genetic differentiation amongst populations of the red-necked (Thylogale thetis) and red-legged (T. stigmatica) pademelon in eastern Australia. Evidence of hybridisation was detected between subspecies of T. stigmatica in central Queensland. Specimens sampled between Eungella and Sarina were found to represent a broad (~90 km) zone of introgression, for both nuclear and mtDNA markers, between T. s. stigmatica (Wet Tropics) and T. s. wilcoxi (south-east Queensland). In addition, individuals sampled from around Proserpine were genetically T. s. stigmatica rather than T. s. wilcoxi, as had previously been assumed. This observation raises some intriguing questions about the dispersal ability of T. stigmatica and the phylogeographic history of moist forest taxa in eastern Australia. Only limited evidence of introgression was detected between sympatric populations of T. thetis and T. s. wilcoxi in south-east Queensland.
Lizard diversity on a rainforest - savanna altitude gradient in north-eastern Australia
Authors: Kutt A. S. , Bateman B. L. , Vanderduys E. P.
Published: October 2011

Mountain ecosystems act as natural experiments for investigating the relationship between environmental heterogeneity and species diversity. A review of the global altitudinal distribution of reptiles identified a diverse range of patterns driven by climate and taxonomy. No Australian examples were included in this analysis. We addressed this gap by surveying the reptile assemblage along an altitude gradient from upland rainforest (~1000 m) through to open savanna woodlands (~350 m) in north-eastern Australia. Reptiles were sampled on four separate occasions between May 2006 and November 2007. Thirty-six species, representing seven families, were recorded along the gradient. As we used only diurnal active searching, snakes and nocturnal geckoes were probably under-sampled; thus we considered only lizards in the analysis of altitude pattern. Lizard species richness peaked at the mid-altitudes (600–900 m, 11–12 spp.) and abundance highest at the lower (<500 m) and higher (>800 m) zones. This pattern is likely a factor of both the increase in radiant heat sources (reduced canopy cover) and increased species packing due to the diversity of niches available (presence of rock cover and increase in saxicolous species). In the lower-altitude sites the high abundance of few species seems linked to the dominance of disturbance-tolerant species. We conclude that lizard richness and abundance patterns on this transect are not necessarily exhibiting a mid-domain effect, but instead are a function of species-specific ecological and habitat requirements.
Geographic distribution of Rhyncholestes raphanurus Osgood, 1924 (Paucituberculata:Caenolestidae), an endemic marsupial of the Valdivian Temperate Rainforest
Authors: Martin Gabriel M.
Published: October 2011

The Chilean shrew opossum (Rhyncholestes raphanurus) is the southernmost representative of the family Caenolestidae (Marsupialia : Paucituberculata). The species lives in temperate forests of southern Chile and Argentina and is currently known from <25 localities, spanning a latitudinal and longitudinal range of 2°44′ (~320 km) and 2°20′ (~190 km), respectively. Species distribution was analysed in a historical, geographic and biogeographic context, with the use of maps at different scales (region, subregion, province, ecoregion, forest types), and two potential distribution models were generated with MaxEnt. The models show a few isolated areas of high prediction values (>50%) in coastal Chile and the Andes from 39°30′ to ~42°S, and most of Chiloé Island, plus a northern and southern expansion of medium to low (<50%) prediction values. The most important environmental variables identified from the models include precipitation and some temperature-related variables. The species occurrence lies within the Andean region, Subantarctic subregion, and Valdivian biogeographic province. At a smaller scale, most of the localities occur in eight of the 22 forest types described for the Valdivian ecoregion, implying narrow ecological requirements. Identification of critical areas through potential distribution modelling may have implications for species conservation and identification of biogeographic patterns.
Ecology of Stimson's python (Antaresia stimsoni) in the MacDonnell Ranges of central Australia
Authors: McDonald Peter J. , Luck Gary W. , Wassens Skye , Pavey Chris R.
Published: October 2011

Stimson’s python (Antaresia stimsoni) is a small nocturnal python (Pythonidae) that occurs throughout Australia’s arid zone. Despite its wide distribution and localised abundance, no field-based studies have been undertaken on this species. We investigated activity patterns, habitat use, diet, and body sizes of A. stimsoni in the MacDonnell Ranges bioregion of the Northern Territory. Data were collected at night by road-cruising along a sealed road transect over 12 consecutive months. We found that the species copes with the extreme weather variability of arid Australia by remaining active over a broad range of air temperatures and maximising activity following rainfall when relative humidity is high and ground-dwelling frogs, a significant prey source, are likely to be abundant. A. stimsoni ceased activity only during the coldest months of the year. The species occurs in a range of vegetation types, with an apparent preference for riparian woodland, and its ability to thrive in the MacDonnell Ranges may be related to the abundance of rock-outcrops for refuge. Our results for diet and body size support previous research based on museum specimens, confirming that A. stimsoni feeds on a range of terrestrial vertebrates and is not sexually dimorphic.
Frames and the experiential basis of the Moving Time metaphor
Authors: Moore Kevin Ezra
Published: October 2011

It is not satisfactory to analyze temporal metaphors such Moving Ego (e.g. We are approaching the end of the year) and Moving Time (e.g. The end of the year is approaching) simply as mappings from SPACE to TIME. In this case, the intuitively obvious experiential basis of Moving Ego leads to a paradox if applied (with suitable adjustments) to Moving Time. Frame analysis makes possible an adequate account of the experiential basis of both metaphors.
FrameNet as a resource for paraphrase research
Authors: Hasegawa Yoko , Lee-Goldman Russell , Kong Albert , Kimi Akita
Published: October 2011

Theoretically as well as empirically, paraphrase is a pivotal concept in many academic and nonacademic fields. And yet, its investigation has made very slow progress, due mainly to the lack of a framework that is versatile enough to deal with the nebulous nature of paraphrase in use. This paper demonstrates how the mechanisms of FrameNet can be utilized as a resource for systematic and coherent research into paraphrase. The semantic framework it provides, including detailed frame descriptions, frame-to-frame relations, and the recording of syntactic information, allows one to see in more principled ways why some set of sentences can be considered paraphrases of each other.
A frame-based approach to connectives
Authors: Uchida Satoru , Fujii Seiko
Published: October 2011

This study proposes an extended FrameNet approach for the description of connectives. The meanings of connectives are described with respect to the two frames evoked by each of the conjoined clauses, whose combinational patterns are termed “frame valences”. Taking the English polysemous connective while as an example, features of each meaning were statistically analyzed based on the frame valences using correspondence analysis. The correspondence analysis has revealed that in the contrastive use the same frame tends to be evoked in the conjoined clauses. To test this result, this study has further examined the contrastive connective whereas, which has firmly supported the results of the correspondence analysis and shown that frames that are closely related via ‘frame-to-frame relations’ can be evoked in the contrastive uses. These findings, in turn, corroborate the validity of the frame-based approach for the description of connectives.
Serious or non-serious?
Authors: Haddington Pentti
Published: October 2011

By drawing on methods used in conversation analysis and interactional linguistics this article discusses the interplay between grammar and social interaction. It investigates a reduplicate linguistic item in Finnish called the ‘joke-joke’ structure. It is shown that the structure is used in interactional sequences in which some prior turn can be understood to be ambiguous in meaning and to have been produced either seriously or non-seriously. Speakers use the ‘joke-joke’ structure, as a kind of metacomment, to shift from an implied serious stance to a non-serious position. In essence, they use the structure to recontextualize and make the prior position ambiguous retroactively. It can thus be considered as a specific form of repair. The structure predominantly occurs in teasing and overstatements. The use of the structure can be seen to reflect the participants’ mutual understanding of sociocultural values. The use of the reduplicate structure can also be seen to be functionally motivated: it can be produced quickly and it iconically intensifies the meaning of ‘joking’. The findings here also support previous findings that reduplicates are frequently used to display emotional states. Finally, this article shows that meanings and understandings frequently emerge and are negotiated in social interaction.
Prosody as a genre-distinguishing feature in Ahtna
Authors: Berez-Kroeker Andrea L.
Published: October 2011

This article is a quantitative examination of the function of prosody in distinguishing between the genres of oral performance and expository discourse in Ahtna, an Athabascan language of south-central Alaska. Within the framework of the intonation unit (e.g., Chafe 1987) I examine features of prosody related to both timing (intonation unit length and duration, pause duration and distribution, and syllable pacing) and pitch (pitch reset, boundary tones, and intonational phrasing). I show to a statistically significant degree that most of the prosodic burden of distinguishing genre is carried by a particular intonation contour that is associated with Ahtna oral performance and causes several measurable distinctions between genres.
Out of the Space of Reasons
Authors: Tindale Christopher W.
Published: October 2011

The paper investigates the ‘logical space of reasons’ as a social space in which rational agents operate and persons in an important sense come to be. Building from an investigation of argumentative agents in Aristotle’s Rhetoric, I discuss both interior and exterior criteria for personhood and propose that the latter shows how argumentation, as a principal activity of the space of reasons, results in the particular kinds of persons we recognize there as rational agents. The overall analysis is indebted to Robert Brandom’s centralizing of the practice of giving and receiving reasons and the suggestive ways this can be applied to the realm of argumentation.
An analysis of three Japanese tags
Authors: Asano-Cavanagh Yuko
Published: October 2011

This paper presents an analysis of three Japanese words — ne, yone, and daroo. These three expressions are often interpreted as tag questions in English. Although these words are semantically closely related, they are not always interchangeable. The subtle differences between them are difficult to grasp, especially for language learners. Numerous studies have been undertaken in order to clarify the meanings of ne, yone, and daroo. However, opinions vary among different scholars, and definitions for these markers are not fully established. This paper applies the Natural Semantic Metalanguage (NSM) approach. It proposes new explications in terms of semantic primes. The proposed semantic formulae clarify the differences between the three expressions and serve as practical tools: Tools which indicate criteria that can assist in choosing an appropriate word for a given situation.
Prosody of humor in Sex and the City
Authors: Urios-Aparisi Eduardo , Wagner Manuela Maria
Published: October 2011

This article investigates the role of prosody in conversational humor in the HBO series Sex and the City (SATC) in an exploratory study. Specifically, we examine how pitch and pauses are part of the prosodic bundle that can be used to mark an utterance as humoristic. We find that the use of prosodic resources participates not only in the marking but also the creation of humor. In this regard, we view pitch variation and pauses as having communicative strategies and cognitive benefits. They are part of the performance of humor and participate in the characterization of the personage. The authors suggest the existence of a repertoire of prosodic devices associated to humor and to a particular discourse.
Between irony and humor
Authors: Hirsch Galia
Published: October 2011

The goal of this paper is to propose a model that distinguishes between irony and humor in the context of literary texts. The comparative model was constructed based on existing models, and elaborated on them, substantiating the model through textual analysis focusing on cues for irony (Clark and Gerrig 1984; Grice 1975, 1978; Haverkate 1990; Sperber and Wilson 1981; Wilson and Sperber 1992;) and cues for humor (Alexander 1997; Jeffers 1995; Oring 1989; Raskin and Attardo 1994). The research was based on four conceptual paradigms: pragmatic studies of irony, pragmatic studies of humor, a pragmatic approach to the study of literary texts, and theories of text interpretation. The textual analysis was based on an existing model for the interpretation of indirect speaker’s meanings (Dascal and Weizman 1987; Weizman and Dascal 1991; 2005), and on the concepts “cues” and “clues” as employed in that model.
Co-creation of experiential qualities
Authors: Uskoković Vuk
Published: October 2011

Cognitive sciences have been interminably in search for a consistent philosophical framework for the description of perceptual phenomena. Most of the frameworks in usage today fall in-between the extremes of constructivism and objective realism. However, whereas constructivist cognitive theories face difficulties when attempting to explain the experiential commonality of different cognitive entities, objectivistic theories fail in explaining the active role of the subject in the formation of experiences. This paper undertakes to compare and eventually combine these two major approaches to describing cognitive phenomena. It is argued that constructivist explanations inevitably refer to a ‘hidden’ ontological source of experience, and that a compromise between the constructivist and realistic standpoints presents a natural basis for understanding cognitive phenomena. A view of all experiences as co-created through an interplay between a constructivist creativity and a realistic source of perceptual stimuli is proposed. A middle ground between the hardly compatible constructivist and objectivistic approaches to experiential realities is proposed from the standpoint of experiential co-creation. Traditionally divided, idealistic and realistic philosophical stances may thus become merged into a single consistent epistemological framework. Many favorable cognitive and psychosomatic consequences may arise from acknowledging the balance between ‘inner’ and ‘outer’ creativity proposed by the co-creational thesis.
Surface plasmon enhancement in gold nanoparticles in the presence of an optical gain medium: an analysis
Authors: Sathiyamoorthy K , Sreekanth K V , Sidharthan R , Murukeshan V M , Xing Bengang
Published: October 2011

The localized surface plasmon (LSP) enhancement in a gold nanoparticle is demonstrated in this paper. The enhancement of LSP is influenced by both size and the dielectric gain medium surrounding the nanoparticles. The nanoparticle is found to induce plasmonic enhancement of varying degrees depending on its size, and it is inferred that a gold nanoparticle of size 60 nm exhibits the maximum LSP for 532 nm excitation. Singularity due to cancellation of SP loss by an infinite gain medium and LSP enhancement are studied using a pump-probe Rayleigh scattering experiment. Gold nanoparticles of average size 60 nm exhibit the lowest threshold power to observe Rayleigh scattering. Furthermore, compared with the bare nanoparticles, a 12.5 fold enhancement of LSP is observed when the nanoparticle of average size 60 nm is kept in the gain medium.
Interface effect on the electronic structure and optical properties of InAs/GaSb superlattices
Authors: Lang Xiao-Li , Xia Jian-Bai
Published: October 2011

The electronic structures of InAs/GaSb superlattices (SLs) are calculated in the framework of eight-band effective-mass theory, including the interface (IF) potential. With two adjustable parameters related to the types of two interfaces, the calculated energy gaps agree excellently with the experimental cut-off energy for a series of samples from different research groups, which proves the importance of IF effect, especially for the short-period SLs. Also, the optical properties of InAs/GaSb SLs are investigated. We proved that the intrinsic absorption coefficient of arbitrary polarization direction
can be expressed as a function of
and
for symmetric-interface SL (D
2d
symmetry). The calculated
agrees well with the experimental data. This method can be applied to predict the cut-off energy of InAs/GaSb SLs and design infrared detectors, and can also be applied to other SLs.
Simulation of current filamentation in a dc-driven planar gas discharge–semiconductor system
Authors: Mokrov M S , Raizer Yu P
Published: October 2011

We have performed a theoretical study of self-organized current filamentation in a dc-driven planar gas discharge–semiconductor system at very low currents and under cryogenic conditions. The discharge instability and the observed formation of current filaments are explained by a thermal mechanism, as proposed in our previous paper. We have found, for the first time, a stationary periodic current structure in a two-dimensional Cartesian geometry from first principles, by numerically solving the general system of continuity equations for ions and electrons, the Poisson equation for the electric field in the gas, together with the equation for gas temperature and the equation for electric field in the semiconductor. The space charge induced electric field redistribution, which usually leads to a discharge instability and is automatically included in the first three equations of the system, is practically absent at the very low currents considered, and thus it cannot be responsible for the discharge instability. This is why another mechanism of filamentation (thermal) should be considered. The calculated periodic current structure agrees with the hexagonal current pattern observed in the experiment, as well as with the periodic current structure found in the frame of the previously developed simple model. This serves as a corroboration of the fact that the thermal effect is essential for pattern formation under the conditions considered.
Surface effects on the postbuckling of nanowires
Authors: Li Yuhang , Song Jizhou , Fang Bo , Zhang Jiazhong
Published: October 2011

Surface effects are important to predict the mechanical behaviour of nanostructures. In this paper, postbuckling of nanowires under uniaxial compression is investigated using an energy method by accounting for both the effects of surface elasticity and residual surface tension. The critical buckling strain and the amplitude of the buckled nanowire are obtained analytically. The results show that the surface effects reduce the amplitude and are negligible when the compressive strain is a few times larger than the critical buckling strain. This study might guide the design of the mechanical properties of microscale and nanoscale structures in wide applications.