bluuebunny/crossref_metadata_2025 huggingface dataset:
A 1 year record of carbonaceous aerosols from an urban site in the Indo‐Gangetic Plain: Characterization, sources, and temporal variability
Authors: Ram Kirpa , Sarin M. M. , Tripathi S. N.
Published: December 2010

This study presents a comprehensive 1 year (January 2007–March 2008) data set on the chemical composition of ambient aerosols collected from an urban location (Kanpur) in the Indo‐Gangetic Plain (IGP) and suggests that the varying strength of the regional emission sources, boundary layer dynamics, and formation of secondary aerosols all contribute significantly to the temporal variability in the mass concentrations of elemental carbon (EC), organic carbon (OC), and water‐soluble OC (WSOC). On average, carbonaceous aerosols contribute nearly one third of the PM10 mass during winter, whereas their fractional mass is only ∼10% during summer. A three‐ to four‐fold increase in the OC and K+ concentrations during winter and a significant linear relation between them suggest biomass burning (wood fuel and agricultural waste) emission as a dominant source. The relatively high OC/EC ratio (average: 7.4 ± 3.5 for n = 66) also supports that emissions from biomass burning are overwhelming for the particulate OC in the IGP. The WSOC/OC ratios vary from 0.21 to 0.70 over the annual seasonal cycle with relatively high ratios in the summer, suggesting the significance of secondary organic aerosols. The long‐range transport of mineral aerosols from Iran, Afghanistan, and the Thar Desert (western India) is pronounced during summer months. The temporal variability in the concentrations of selected inorganic constituents and neutralization of acidic species (SO42− and NO3−) by NH4+ (dominant during winter) and Ca2+ (in summer) reflect conspicuous changes in the source strength of anthropogenic emissions.
Heterogeneous uptake of carbonyl sulfide onto kaolinite within a temperature range of 220–330 K
Authors: Liu Yongchun , Ma Jinzhu , Liu Chang , He Hong
Published: December 2010

In this study the heterogeneous uptake of carbonyl sulfide (OCS) onto kaolinite was investigated using a Knudsen cell reactor within the temperature range of 220–330 K. Results showed that OCS could only be adsorbed at Al‐OH sites on kaolinite reversibly within this temperature region. The initial true uptake coefficient was measured to be (1.68 ± 0.12) × 10−7 at 300 K. It showed no observable dependence on the pressure of OCS, while it varied significantly with temperature, and can be expressed as γt = exp(1293/T − 20.0)/[1 + exp(1293/T − 20.0]. The values of ΔHobs and ΔSobs during the adsorption process were −10.7 ± 1.1 kJ mol−1 and −166.3 ± 4.5 J K−1 mol−1, respectively. The activation energy for desorption of OCS on kaolinite was 19.5 ± 1.1 kJ mol−1. The uptake of OCS by kaolinite owing to reversible physisorption may have little influence on the sink of OCS in the atmosphere.
Toward understanding the dust deposition in Antarctica during the Last Glacial Maximum: Sensitivity studies on plausible causes
Authors: Li Fuyu , Ramaswamy V. , Ginoux Paul , Broccoli Anthony J. , Delworth Thomas , Zeng Fanrong
Published: December 2010

Understanding the plausible causes for the observed high dust concentrations in Antarctic ice cores during the Last Glacial Maximum (LGM) is crucial for interpreting the Antarctic dust records in the past climates and could provide insights into dust variability in future climates. Using the Geophysical Fluid Dynamics Laboratory (GFDL) General Circulation Models, we conduct an investigation into the various factors modulating dust emission, transport, and deposition, with a view toward an improved quantification of the LGM dust enhancements in the Antarctic ice cores. The model simulations show that the expansion of source areas and changes in the Antarctic ice accumulation rates together can account for most of the observed increase of dust concentrations in the Vostok, Dome C, and Taylor Dome cores, but there is an overestimate of the LGM/present ratio in the case of the Byrd core. The source expansion due to the lowering of sea level yields a factor of 2–3 higher contribution than that due to the reduction of continental vegetation. The changes in other climate parameters (e.g., SH precipitation change) are estimated to be relatively less important within the context of this sensitivity study, while the model‐simulated LGM surface winds yield a 20%–30% reduction rather than an increase in dust deposition in Antarctica. This research yields insights toward a fundamental understanding of the causes for the significant enhancement of the dust deposition in the Antarctic ice cores during the LGM.
Simulating the one‐dimensional structure of Titan's upper atmosphere: 2. Alternative scenarios for methane escape
Authors: Bell Jared M. , Bougher Stephen W. , Waite J. Hunter , Ridley Aaron J. , Magee Brian A. , Mandt Kathleen E. , Westlake Joseph , DeJong Anna D. , De La Haye Virginie , Bar‐Nun Akiva , Jacovi Ronen , Toth Gabor , Gell David , Fletcher Gregory
Published: December 2010

In Bell et al. (2010) (paper 1), we provide a series of benchmark simulations that validate a newly developed Titan Global Ionosphere‐Thermosphere Model (T‐GITM) and calibrate its estimates of topside escape rates with recent work by Cui et al. (2008), Strobel (2009), and Yelle et al. (2008). Presently, large uncertainties exist in our knowledge of the density and thermal structure of Titan's upper atmosphere between the altitudes of 500 km and 1000 km. In this manuscript, we explore a spectrum of possible model configurations of Titan's upper atmosphere that are consistent with observations made by the Cassini Ion‐Neutral Mass Spectrometer (INMS), Composite Infrared Spectrometer, Cassini Plasma Spectrometer, Magnetospheric Imaging Instrument, and by the Huygens Gas Chromatograph Mass Spectrometer and Atmospheric Science Instrument. In particular, we explore the ramifications of multiplying the INMS densities of Magee et al. (2009) by a factor of 3.0, which significantly alters the overall density, thermal, and dynamical structures simulated by T‐GITM between 500 km and 1500 km. Our results indicate that an entire range of topside CH4 escape fluxes can equivalently reproduce the INMS measurements, ranging from ∼108 − 1.86 × 1013 molecules m−2 s−1 (referred to the surface). The lowest topside methane escape rates are achieved by scaling the INMS densities by a factor of 3.0 and either (1) increasing the methane homopause altitude to ∼1000 km or (2) including a physicochemical loss referred to as aerosol trapping. Additionally, when scaling the INMS densities by a factor of 3.0, we find that only Jeans escape velocities are required to reproduce the H2 measurements of INMS.
Structure and dynamics of the Martian lower and middle atmosphere as observed by the Mars Climate Sounder: Seasonal variations in zonal mean temperature, dust, and water ice aerosols
Authors: McCleese D. J. , Heavens N. G. , Schofield J. T. , Abdou W. A. , Bandfield J. L. , Calcutt S. B. , Irwin P. G. J. , Kass D. M. , Kleinböhl A. , Lewis S. R. , Paige D. A. , Read P. L. , Richardson M. I. , Shirley J. H. , Taylor F. W. , Teanby N. , Zurek R. W.
Published: December 2010

The first Martian year and a half of observations by the Mars Climate Sounder aboard the Mars Reconnaissance Orbiter has revealed new details of the thermal structure and distributions of dust and water ice in the atmosphere. The Martian atmosphere is shown in the observations by the Mars Climate Sounder to vary seasonally between two modes: a symmetrical equinoctial structure with middle atmosphere polar warming and a solstitial structure with an intense middle atmosphere polar warming overlying a deep winter polar vortex. The dust distribution, in particular, is more complex than appreciated before the advent of these high (∼5 km) vertical resolution observations, which extend from near the surface to above 80 km and yield 13 dayside and 13 nightside pole‐to‐pole cross sections each day. Among the new features noted is a persistent maximum in dust mass mixing ratio at 15–25 km above the surface (at least on the nightside) during northern spring and summer. The water ice distribution is very sensitive to the diurnal and seasonal variation of temperature and is a good tracer of the vertically propagating tide.
Venus' atomic hot oxygen environment
Authors: Gröller H. , Shematovich V. I. , Lichtenegger H. I. M. , Lammer H. , Pfleger M. , Kulikov Yu. N. , Macher W. , Amerstorfer U. V. , Biernat H. K.
Published: December 2010

We present a Monte Carlo study of the atomic hot oxygen corona of Venus. In this model we consider elastic, inelastic, and quenching collisions between the traced hot particle and the ambient neutral atmosphere as well as differential cross sections to determine the scattering angle in the collisions. We also include rotational and vibrational excitation energies for the calculation of the initial energy of the produced hot oxygen atoms. Our results indicate that the differential cross sections and the fraction between elastic, inelastic, and quenching collisions are the most sensitive parameters which effect the corona density. We found that the hot O densities inferred from PVO observations can only be reproduced during high solar activity based on a forward scattering model but without inelastic and quenching collisions. The corona densities for low solar activity (VEX solar conditions) are about a factor of 2–3 smaller than for high solar activity.
Development of a formal likelihood function for improved Bayesian inference of ephemeral catchments
Authors: Smith Tyler , Sharma Ashish , Marshall Lucy , Mehrotra Raj , Sisson Scott
Published: December 2010

The application of formal Bayesian inferential approaches in hydrologic modeling is often criticized for requiring explicit assumptions to be made about the distribution of the errors via the likelihood function. These assumptions can be adequate in some situations, but often little attention is paid to the selection of an appropriate likelihood function. This paper investigates the application of Bayesian methods in modeling ephemeral catchments. We consider two modeling case studies, including a synthetically generated data set and a real data set of an arid Australian catchment. The case studies investigate some typical forms of the likelihood function which have been applied widely by previous researchers, as well as introducing new implementations aimed at better addressing likelihood function assumptions in dry catchments. The results of the case studies indicate the importance of explicitly accounting for model residuals that are highly positively skewed due to the presence of many zeros (zero inflation) arising from the dry spells experienced by the catchment. Specifically, the form of the likelihood function was found to significantly impact the calibrated parameter posterior distributions, which in turn have the potential to greatly affect the uncertainty estimates. In each application, the likelihood function that explicitly accounted for the nonconstant variance of the errors and the zero inflation of the errors resulted in (1) equivalent or better fits to the observed discharge in both timing and volume, (2) superior estimation of the uncertainty as measured by the reliability and sharpness metrics, and (3) more linear quantile‐quantile plots indicating the errors were more closely matched to the assumptions of this form of the likelihood function.
Measurement of Cerebral Blood Flow Responses to the Thigh Cuff Maneuver: A Comparison of TCD with a Novel MRI Method
Authors: Saeed Nazia P , Horsfield Mark A , Panerai Ronney B , Mistri Amit K , Robinson Tom G
Published: December 2010

Cerebral autoregulation (CA) describes the mechanism responsible for maintaining cerebral blood flow (CBF) relatively constant, despite changes in mean arterial blood pressure (ABP). This paper introduces a novel method for assessing CA using magnetic resonance imaging (MRI). Images are rapidly and repeatedly acquired using a gradient-echo echo-planar imaging pulse sequence for a period of 4minutes, during which a transient decrease in ABP is induced by rapid release of bilateral thigh cuffs. The method was validated by comparing the observed MRI signal intensity change with the CBF velocity change in the middle cerebral arteries, as measured by transcranial Doppler (TCD) ultrasound, using a standardized thigh cuff maneuver in both cases. Cross-correlation analysis of the response profiles from the left and right hemispheres showed a greater consistency for MRI measures than for TCD, both for interhemisphere comparisons and for repeated measures. The new MRI method may provide opportunities for assessing regional autoregulatory changes following acute stroke, and in other conditions in which poor autoregulation is implicated.
Nano-enabled Biological Materials
Authors: Alicea Bradly
Published: December 2010

This talk is an attempt to define a new field called “Nano-enabled Biological Tissues”. As such, this talk serves as a review of both the theoretical underpinnings and relevant recent results.The presentation is divided into several parts:* in the first section (slides 3-4), the concept of nano-enabled tissues are introduced as a complex system that can be engineered at multiple scales.* the second section (slides 5-12) contains three essential ingredients to achieve the technological vision. Current examples of each ingredient are introduced separately.* in the third section (slides 13-17), additional essential ingredients are considered. This includes strategies for system construction (top-down vs. bottom-up), and additional tools for functionality such as computational intelligence.
Wavefield characterization of nearly diffraction-limited focused hard x-ray beam with size less than 10 nm
Authors: Kimura Takashi , Mimura Hidekazu , Handa Soichiro , Yumoto Hirokatsu , Yokoyama Hikaru , Imai Shota , Matsuyama Satoshi , Sano Yasuhisa , Tamasaku Kenji , Komura Yoshiki , Nishino Yoshinori , Yabashi Makina , Ishikawa Tetsuya , Yamauchi Kazuto
Published: December 2010

In situ wavefront compensation is a promising method to realize a focus size of only a few nanometers for x-ray beams. However, precise compensation requires evaluation of the wavefront with an accuracy much shorter than the wavelength. Here, we characterized a one-dimensionally focused beam with a width of 7 nm at 20 keV using a multilayer mirror. We demonstrate that the wavefront can be determined precisely from multiple intensity profiles measured around the beamwaist. We compare the phase profiles recovered from intensity profiles measured under the same mirror condition but with three different aperture sizes and find that the accuracy of phase retrieval is as small as λ/12.
Simulations of the gyroid phase in diblock copolymers with the Gaussian disphere model
Authors: Karatchentsev A. , Sommer J.-U.
Published: December 2010

Pure melts of asymmetric diblock copolymers are studied by means of the off-lattice Gaussian disphere model with Monte-Carlo kinetics. In this model, a diblock copolymer chain is mapped onto two soft repulsive spheres with fluctuating radii of gyration and distance between centers of mass of the spheres. Microscopic input quantities of the model such as the combined probability distribution for the radii of gyration and the distance between the spheres as well as conditional monomer number densities assigned to each block were derived in the previous work of F. Eurich and P. Maass [J. Chem. Phys. 114, 7655 (2001)] within an underlying Gaussian chain model. The polymerization degree of the whole chain as well as those of the individual blocks are freely tunable parameters thus enabling a precise determination of the regions of stability of various phases. The model neglects entanglement effects which are irrelevant for the formation of ordered structures in diblock copolymers and which would otherwise unnecessarily increase the equilibration time of the system. The gyroid phase was reproduced in between the cylindrical and lamellar phases in systems with box sizes being commensurate with the size of the unit cell of the gyroid morphology. The region of stability of the gyroid phase was studied in detail and found to be consistent with the prediction of the mean-field theory. Packing frustration was observed in the form of increased radii of gyration of both blocks of the chains located close to the gyroid nodes.
Sensitized Yb3+ emission in (Nd, Yb):Y3Al5O12 transparent ceramics
Authors: Lupei V. , Lupei A. , Gheorghe C. , Ikesue A.
Published: December 2010

The characteristics of Nd→Yb energy transfer in (Nd, Yb):Y3Al5O12 (YAG) transparent ceramics, obtained from steady state and dynamic spectral studies on different single doped and codoped samples, prepared by solid state synthesis, are presented. The Yb3+ emission in codoped (Nd, Yb):YAG samples under cw excitation of the donors (Nd3+) revealed efficient energy transfer to Yb3+ (at low temperatures too), due to the overlap of the Nd3+ F43/2→I49/2 emission and Yb3+ F27/2→F25/2 absorption. From the global decays of the Nd3+ F43/2 level in single and codoped samples, the transfer efficiencies were estimated; they increase with Yb3+ content reaching ∼93% for 1 at. % Nd, 5 at. % Yb:YAG sample. The mechanisms and parameters of the Nd→Yb energy transfer were inferred from the Nd3+ decays in the codoped samples, after the separation of the self-quenching inside the donors (Nd3+) from the transfer to acceptors (Yb3+). It was proved that the Nd→Yb energy is resonant and dominated by dipole-dipole interactions. Due to the large transfer efficiencies, (Nd, Yb):YAG ceramic could be a promising material for Yb3+ emission under pumping in strong Nd3+ absorption lines.
Compression and strong rarefaction in high power impulse magnetron sputtering discharges
Authors: Horwat David , Anders André
Published: December 2010

Gas compression and strong rarefaction have been observed for high power impulse magnetron sputtering (HIPIMS) discharges using a copper target in argon. Time-resolved ion saturation currents of 35 probes were simultaneously recorded for HIPIMS discharges operating far above the self-sputtering runaway threshold. The argon background pressure was a parameter for the evaluation of the spatial and temporal development of the plasma density distribution. The data can be interpreted by a massive onset of the sputtering flux (sputter wind) that causes a transient densification of the gas, followed by rarefaction and the replacement of gas plasma by the metal plasma of sustained self-sputtering. The plasma density pulse follows closely the power pulse at low pressure. At high pressure, the relatively remote probes recorded a density peak only after the discharge pulse, indicative for slow, diffusive ion transport.
Riemann surface approach to bound and resonant states for a nonlocal potential
Authors: Grama Cornelia , Grama N. , Zamfirescu I.
Published: December 2010

The Riemann surface approach to bound and resonant states is extended to the case of a separable nonlocal potential that is constant on a certain domain of the inner region and vanishes in the rest of the domain. The approach consists in the construction of the Riemann surface \documentclass[12pt]{minimal}\begin{document}$R_g$\end{document}Rg of the S-matrix pole function k = k(g) over the g-plane, where g is the strength of the complex nonlocal potential. On the Riemann surface \documentclass[12pt]{minimal}\begin{document}$R_g$\end{document}Rg the pole function k = k(g) is single-valued and analytic. The branch points of the pole function k = k(g) and their k-plane images are determined and analyzed as a function of the position of the region of nonlocality. The Riemann surface of the S-matrix pole function is constructed. According to the Riemann surface approach to each bound or resonant state a sheet of the Riemann surface \documentclass[12pt]{minimal}\begin{document}$R_g$\end{document}Rg is associated. All the natural modes (bound and resonant states) of the system are identified and treated in a unified way. The nonlocal potential generates narrow resonant states that cannot be produced by a local potential.
Electron-hole duality during band-to-band tunneling process in graphene-nanoribbon tunnel-field-effect-transistors
Authors: Sarkar Deblina , Krall Michael , Banerjee Kaustav
Published: December 2010

This letter provides clear insight into the interplay between electron and hole characteristics of carriers within the forbidden gap during the band-to-band tunneling process, taking graphene-nanoribbons as an example. Accurate numerical models are presented and analytical formulas for tunneling probabilities are derived for both source/drain to channel and direct source-drain tunneling based on the Wentzel–Kramers–Brillouin (WKB) method. It is shown that not considering the electron-hole duality can lead to significant errors in numerical calculations, and more importantly, lack of proper understanding of the phenomenon gives rise to seriously misleading conclusions. Furthermore, the regime of validity of the WKB approximation for graphene-nanoribbon tunnel-field-effect-transistors is discussed in light of the electron-hole duality concept.
Simulation and theory for two-dimensional beam-plasma instability
Authors: Yi Sumin , Rhee Tongnyeol , Ryu Chang-Mo , Yoon Peter H.
Published: December 2010

A comparative study of the dynamics of the electron beam-plasma system in two spatial dimensions is carried out by means of particle-in-cell (PIC) simulation and quasilinear theory. In the literature, the beam-plasma instability is usually studied with one-dimensional assumption. Among the few works that include higher-dimensional effects are two- and three-dimensional quasilinear theory and two-dimensional PIC simulations. However, no efforts were made to compare the theory and simulation side by side. The present paper carries out a detailed comparative study of two-dimensional simulation and quasilinear theory. It is found that the quasilinear theory quite adequately accounts for most important features associated with the simulation result. For instance, the particle diffusion time scale, the maximum wave intensity, dynamical development of the electron distribution function, and the change in the wave spectrum all agree quantitatively. However, certain nonlinear effects such as the Langmuir condensation phenomenon are not reproduced by the quasilinear theory. Nevertheless, the present paper verifies that the simple quasilinear theory is quite effective for the study of beam-plasma instability for the present choice of parameters.
Field emission and material transfer in microswitches electrical contacts
Authors: Vincent M. , Rowe S. W. , Poulain C. , Mariolle D. , Chiesi L. , Houzé F. , Delamare J.
Published: December 2010

Material transfer from one electrical contact part to the other has already been reported in microswitches operating under hot switching conditions. By using an atomic force microscope with a conductive cantilever, we highlighted that electrons are emitted from the cathode when electrode separation becomes less than a few tens of nanometers. This electronic emission proves to follow Fowler–Nordheim theory and leads to the damage of the opposite contact member (anode) by impact heating. Anode material evaporates under this extreme heating and deposits on the opposite contact member (cathode), leading to a material transfer from anode to cathode.
Effective method to identify the vacancies in crystalline GeTe
Authors: Tong F. , Miao X. S. , Wu Y. , Chen Z. P. , Tong H. , Cheng X. M.
Published: December 2010

X-ray diffraction and photoelectron spectroscopy of different Co-doped concentration GeTe have been made to identify the vacancies in rock-salt GeTe. The results show that Co occupies germanium vacancy and forms Co–Te bond, but the alloy retains a rock-salt structure when the concentration of doped Co is less than the vacancy ratio in crystalline GeTe. If we construct 8% germanium vacancy and relative distortion in rock-salt GeTe, the magnetism calculation based on spin-polarized density functional theory of Co-doped GeTe agrees well with superconducting quantum interference device magnetometer result. From experiment and calculation results, we can confirm the existence of vacancies in rock-salt GeTe and the ratio is 8%.
Characterizing ultrashort optical pulses using second-order nonlinear nanoprobes
Authors: Li Haifeng , Zhang Zhe , Xu Qian , Shi Kebin , Jia Yaoshun , Zhang Baigang , Xu Yong , Liu Zhiwen
Published: December 2010

We report a second-order nonlinear nanoprobe for characterizing ultrafast optical near fields. The proposed nanoprobe comprises second harmonic nanocrystals attached to a carbon nanotube, which is in turn attached to a silica fiber taper. We demonstrate in situ pulse characterization directly in the air core of a photonic crystal fiber. Further, it is shown that nanoprobes containing a single nanocrystal in the tip of the nanotube can be fabricated by auxiliary focused ion beam nanomilling. These results indicate that the proposed nanoprobe can open an avenue for probing the evolution of ultrafast optical fields in complex three-dimensional micro- or nanostructures.
Thermal stability of TiN/HfSiON gate stack structures studied by synchrotron-radiation photoemission spectroscopy
Authors: Toyoda S. , Kamada H. , Kumigashira H. , Oshima M. , Iwamoto K. , Sukegawa T. , Liu Z.
Published: December 2010

We have investigated the thermal stability of TiN/HfSiON gate stack structures using synchrotron-radiation photoemission spectroscopy. Spectral intensities of the Si-oxide components in Si 2p core-level spectra systematically increase with annealing temperature, which strongly depends on the thickness of the TiN metal gate layer. Changes brought by annealing procedures in depth profiles of atomic concentration indicate segregation of Si-atoms at the TiN surface. Furthermore, chemical-state-resolved depth analyses by angle-resolved photoemission spectroscopy suggest formation of TiSix and HfNy components due to chemical bond breaking in the HfSiON layer during TiN film growth. This can be related to the degradation of thermal stability.
Switching control of resistive switching devices
Authors: Chen An
Published: December 2010

Switching current control plays a critical role in the operation of resistive switching devices. Both on-state resistance and maximum reset current show strong dependence on the current limit during set switching. The dependence in unipolar switching devices can be explained by the power-driven nature of reset and dynamic competition between set and reset forces. Effective switching control improves device characteristics including uniform resistance distribution and low reset current. However, it also presents challenges for the choice of selection devices and the feasibility of unconventional architectures for resistive switching devices.
Effect of domain structure on dielectric nonlinearity in epitaxial BiFeO3 films
Authors: Ihlefeld J. F. , Folkman C. M. , Baek S. H. , Brennecka G. L. , George M. C. , Carroll J. F. , Eom C. B.
Published: December 2010

Rayleigh analysis has been used to investigate dielectric nonlinearity in epitaxial (001)-oriented BiFeO3 films with engineered domain structures from single- to four-variant and stripe domain samples with 71° and 109° domain walls. Single-domain variant films display minimal irreversible contributions, whereas the ratio of irreversible to reversible contributions increases by approximately one order of magnitude as the number of variants increases to two- and four-variants, respectively. These measurements indicate that the density of domain walls and degree of domain wall complexity influence the number and strength of domain wall pinning sites.
A graphene quantum dot with a single electron transistor as an integrated charge sensor
Authors: Wang Lin-Jun , Cao Gang , Tu Tao , Li Hai-Ou , Zhou Cheng , Hao Xiao-Jie , Su Zhan , Guo Guang-Can , Jiang Hong-Wen , Guo Guo-Ping
Published: December 2010

A quantum dot (QD) with an integrated charge sensor is becoming a common architecture for a spin or charge based solid state qubit. To implement such a structure in graphene, we have fabricated a twin-dot structure in which the larger dot serves as a single electron transistor (SET) to read out the charge state of the nearby gate controlled small QD. A high SET sensitivity of 10−3e/Hz allowed us to probe Coulomb charging as well as excited state spectra of the QD, even in the regime where the current through the QD is too small to be measured by conventional transport means.
Genetic signals of origin, spread, and introgression in a large sample of maize landraces
Authors: van Heerwaarden Joost , Doebley John , Briggs William H. , Glaubitz Jeffrey C. , Goodman Major M. , de Jesus Sanchez Gonzalez Jose , Ross-Ibarra Jeffrey
Published: December 2010

The last two decades have seen important advances in our knowledge of maize domestication, thanks in part to the contributions of genetic data. Genetic studies have provided firm evidence that maize was domesticated from Balsas teosinte (
Zea mays
subspecies
parviglumis
), a wild relative that is endemic to the mid- to lowland regions of southwestern Mexico. An interesting paradox remains, however: Maize cultivars that are most closely related to Balsas teosinte are found mainly in the Mexican highlands where subspecies
parviglumis
does not grow. Genetic data thus point to primary diffusion of domesticated maize from the highlands rather than from the region of initial domestication. Recent archeological evidence for early lowland cultivation has been consistent with the genetics of domestication, leaving the issue of the ancestral position of highland maize unresolved. We used a new SNP dataset scored in a large number of accessions of both teosinte and maize to take a second look at the geography of the earliest cultivated maize. We found that gene flow between maize and its wild relatives meaningfully impacts our inference of geographic origins. By analyzing differentiation from inferred ancestral gene frequencies, we obtained results that are fully consistent with current ecological, archeological, and genetic data concerning the geography of early maize cultivation.
Explicit knowledge and learning in SLA
Authors: Roehr Karen
Published: December 2010

SLA researchers agree that explicit knowledge and learning play an important role in adult L2 development. In the field of cognitive linguistics, it has been proposed that implicit and explicit knowledge differ in terms of their internal category structure and the processing mechanisms that operate on their representation in the human mind. It has been hypothesized that linguistic constructions which are captured easily by metalinguistic descriptions can be learned successfully through explicit processes, resulting in accurate use. However, increased accuracy of use arising from greater reliance on explicit processing may lead to decreased fluency. Taking these hypotheses as a starting point, I present a case study of an adult L2 learner whose development of oral proficiency was tracked over 17 months. Findings indicate that explicit knowledge and learning have benefits as well as limitations. Use of metalinguistic tools was associated with increased accuracy; moreover, there was no obvious trade-off between accuracy and fluency. At the same time, resource-intensive explicit processing may impose too great a cognitive load in certain circumstances, apparently resulting in implicit processes taking over. I conclude that explicit and implicit knowledge and learning should be considered together in order to gain a full understanding of L2 development.
Empirical observation of term variations and principles for their description
Authors: Daille Béatrice , Habert Benoît , Jacquemin Christian , Royauté Jean
Published: December 2010

Terms are often supposed not to be prone to variation. Empirical observation of terms in various corpora (telecommunication, physics, medicine) shows, on the contrary, the quantitative and qualitative importance of term variation. We give a precise linguistic description of the rules relating to controlled terms and observed variants and of the constraints on these rules. This description leads to novel means of enriching terminologies via the generation of possible term variants or the simplification of nominal parse trees in order to discover potential variants.
Methods of automatic term recognition
Authors: Kageura Kyo , Umino Bin
Published: December 2010

Following the growing interest in "corpus-based" approaches to computational linguistics, a number of studies have recently appeared on the topic of automatic term recognition or extraction. Because a successful term-recognition method has to be based on proper insights into the nature of terms, studies of automatic term recognition not only contribute to the applications of computational linguistics but also to the theoretical foundation of terminology. Many studies on automatic term recognition treat interesting aspects of terms, but most of them are not well founded and described.
This paper tries to give an overview of the principles and methods of automatic term recognition. For that purpose, two major trends are examined, i.e., studies in automatic recognition of significant elements for indexing mainly carried out in information-retrieval circles and current research in automatic term recognition in the field of computational linguistics.
Definition of an evaluation grid for term-extraction software
Authors: L'Homme Marie-Claude , Benali Loubna , Bertrand Claudine , Lauduique Patricia
Published: December 2010

This paper examines evaluation criteria for term-extraction software. These tools have gained popularity over the past few years, but they come in all sorts of structures and their performance cannot be compared (qualitatively) to that of humans performing the same task. The lists obtained after an automated extraction must always be filtered by users. The evaluation form proposed here consists of a certain number of preprocessing criteria (such as the language analyzed by the software, identification strategies used, etc.) and a postprocessing criterion (performance of software) that users must take into account before they start using such systems. Each criterion is defined and illustrated with examples. Commercial tools have also been tested.
An information-base system based on the self-organization of concepts represented by terms
Authors: Lai Jingjuan , Chen Hanxiong , Fujiwara Yuzuru
Published: December 2010

Since multimedia information is complicated inform and vast in amount, conventional database-management systems or knowledge-base-management systems are hardly appropriate to store, manage, and utilize expertise effectively. A new type of information model is developed according to an analysis of the information used by specialists for research and development, and a prototype information-management system is implemented. The system consists of three parts: (1) flexible storage without special constraints on format and representation; (2) self-organization of terms by extracting semantic relationships among them; and (3) advanced utilization functions such as analogical reasoning, inductive inference, abductive inference, as well as information retrieval, numerical calculation, and deductive inference. Thesauri which are automatically compiled and refined are used as conceptual structures of the information. Thus obtained, conceptual structures can be used for sophisticated applications, including analogical reasoning, induction, and abduction. The principle of open-world reasoning and an algorithm of analogy are developed. An example of practical application to polymer information is presented.
Why English definitions should begin with articles in ISO terminology standards
Authors: Gilreath Charles T.
Published: December 2010

ISO 10241:1992 ("International Terminology Standards — Preparation and Layout") is a basic standard which prescribes a uniform method for drafting the standard glossaries known as ISO terminology standards. Among other problems with ISO 10241 is a clause which generally prohibits the use of articles at the beginning of definitions. Here I shall identify two specific reasons why English definitions should begin with articles. They are the enormous precedent for this practice throughout the English language and the semantic precision that is lost when articles are missing. I maintain that there is no place in ISO for a rule that forces English or any other language into violation of its semantic precision and norms of usage.
Macromolecule and polymer
Authors: Staudinger-Woit Magda
Published: December 2010

The article suggests that instead of the obsolete and imprecise "polymer", the exact term is "macromolecule ", and in the future it should be applied in all fields of macromolecular science.
Theories 'of' terminology
Authors: Kageura Kyo
Published: December 2010

Traditional "theory " of terminology, as far as I understand it, has two shortcomings. The first, which is now pointed out by many researchers, is that the way in which the study of terms is viewed is too restricted, and the descriptive means such as "concepts" are not rich enough. This becomes clear if one faces actual terms as empirical objects. The second shortcoming is that there is no guarantee in the "theoretical" framework itself that the resultant description can logically be claimed to be about terms and/or terminology. This shortcoming seems to have been overlooked by most researchers. This paper is devoted to an examination of this second problem, with special reference to the study of term formation.
In search of a foundation
Authors: Sager Juan C.
Published: December 2010

The major objection to a purely linguistic theory of terms stems from the fact that formally terms are indistinguishable from words. For a justification of terms as a distinct category of lexical items we have to look in two areas: (1) the things terms refer to and (2) the nature of this reference. An examination of some philosophical writings on the subject will lead to an attempt to explain the different nature of terms.
"Concepts" and Term Hierarchy
Authors: Lara Luis Fernando
Published: December 2010

The paper proposes a coherent, exhaustive and verifiable theory of terminology. It demonstrates the empirical and methodological inadequacy of the notion of "concept" in philosophical semantics and Wusterian terminology. It maintains that the social nature of cognition allocates linguistics an important role in the construction and validation of human knowledge. It suggests a four stage hierarchy for classifying lexical units based upon four successive stages of knowledge acquisition.
Why traditional terminology theory impedes a realistic description of categories and terms in the life sciences
Authors: Temmerman Rita
Published: December 2010

On the basis of an empirical study of categorisation and lexicalisation processes in a corpus of English language scientific publications in the domain of the life sciences, we claim that traditional terminology theory (the Vienna school) has five principles which impede a realistic description of many categories and terms. We propose an alternative socio-cognitive terminology theory inspired by cognitive semantics.
Principes formels et fonctionnels de la variation en terminologie
Authors: Faulstich Enilde
Published: December 2010

The theory of terminology has to admit two temporal ways for the analysis of terms in the discourse: one concerns the synchronic aspect where variants present the same referential signifié, the other, which is diachronic, accounts for changes in meaning, and so permits us to reconstruct the historical development of conceptual structures. To enable us to deal with the (re)organization of the conceptual structures, we suggest that there is a dynamic word-concept relation within languages. The scope of this paper is the functional analysis of the terminology in the synchronic and diachronic axes of social discourses. Its purpose is to prove that scientific and technical as well as the popular terminologies do not belong exclusively to the synchronic axis of languages and that terminologies have their own history and contribute to the history of languages.
Sciences, language and social interaction
Authors: Barona Josep Lluis
Published: December 2010

The traditional perception of terminology as a tool for scientists used mainly in standardisation and for the regulation of the term-concept relationship is currently undergoing a critical re-appraisal with the intention of transcending purely pragmatic considerations at the moment of formulating the foundations for a new theory of terms. The present paper concentrates on three issues. First it critically examines the traditional concept of what constitutes a scientific discipline; secondly it re-assesses the idea of the objectivity of scientific knowledge from the standpoint of the concept of "Denkstil", and, finally, it discusses the difficult tension between popularisation of science and social interaction.
PP6 puts the brakes on spindle assembly
Authors: Short Ben
Published: December 2010

The phosphatase limits Aurora A's kinase activity during mitosis.
Ramanujan Hegde: The prion puzzle and protein translocation
Authors: Sedwick Caitlin
Published: December 2010

Hegde uses prion protein as a model to explore how cells handle protein translocation and trafficking.
SIRT1 contributes to telomere maintenance and augments global homologous recombination
Authors: Palacios Jose A. , Herranz Daniel , De Bonis Maria Luigia , Velasco Susana , Serrano Manuel , Blasco Maria A.
Published: December 2010

Yeast Sir2 deacetylase is a component of the silent information regulator (SIR) complex encompassing Sir2/Sir3/Sir4. Sir2 is recruited to telomeres through Rap1, and this complex spreads into subtelomeric DNA via histone deacetylation. However, potential functions at telomeres for SIRT1, the mammalian orthologue of yeast Sir2, are less clear. We studied both loss of function (SIRT1 deficient) and gain of function (SIRT1super) mouse models. Our results indicate that SIRT1 is a positive regulator of telomere length in vivo and attenuates telomere shortening associated with aging, an effect dependent on telomerase activity. Using chromatin immunoprecipitation assays, we find that SIRT1 interacts with telomeric repeats in vivo. In addition, SIRT1 overexpression increases homologous recombination throughout the entire genome, including telomeres, centromeres, and chromosome arms. These findings link SIRT1 to telomere biology and global DNA repair and provide new mechanistic explanations for the known functions of SIRT1 in protection from DNA damage and some age-associated pathologies.
Targeted ablation of TRAF6 inhibits skeletal muscle wasting in mice
Authors: Paul Pradyut K. , Gupta Sanjay K. , Bhatnagar Shephali , Panguluri Siva K. , Darnay Bryant G. , Choi Yongwon , Kumar Ashok
Published: December 2010

Skeletal muscle wasting is a major human morbidity, and contributes to mortality in a variety of clinical settings, including denervation and cancer cachexia. In this study, we demonstrate that the expression level and autoubiquitination of tumor necrosis factor (α) receptor adaptor protein 6 (TRAF6), a protein involved in receptor-mediated activation of several signaling pathways, is enhanced in skeletal muscle during atrophy. Skeletal muscle–restricted depletion of TRAF6 rescues myofibril degradation and preserves muscle fiber size and strength upon denervation. TRAF6 mediates the activation of JNK1/2, p38 mitogen-activated protein kinase, adenosine monophosphate–activated protein kinase, and nuclear factor κB, and induces the expression of muscle-specific E3 ubiquitin ligases and autophagy-related molecules in skeletal muscle upon denervation. Inhibition of TRAF6 also preserves the orderly pattern of intermyofibrillar and subsarcolemmal mitochondria in denervated muscle. Moreover, depletion of TRAF6 prevents cancer cachexia in an experimental mouse model. This study unveils a novel mechanism of skeletal muscle atrophy and suggests that TRAF6 is an important therapeutic target to prevent skeletal muscle wasting.
Nessun Dorma, a novel centralspindlin partner, is required for cytokinesis in Drosophila spermatocytes
Authors: Montembault Emilie , Zhang Wei , Przewloka Marcin R. , Archambault Vincent , Sevin Emeric W. , Laue Ernest D. , Glover David M. , D'Avino Pier Paolo
Published: December 2010

Cytokinesis, the final step of cell division, usually ends with the abscission of the two daughter cells. In some tissues, however, daughter cells never completely separate and remain interconnected by intercellular bridges or ring canals. In this paper, we report the identification and analysis of a novel ring canal component, Nessun Dorma (Nesd), isolated as an evolutionarily conserved partner of the centralspindlin complex, a key regulator of cytokinesis. Nesd contains a pectin lyase–like domain found in proteins that bind to polysaccharides, and we present evidence that it has high affinity for β-galactosides in vitro. Moreover, nesd is an essential gene in Drosophila melanogaster, in which it is required for completion of cytokinesis during male meiosis and possibly in female germline cells. Our findings indicate that Nesd is a novel carbohydrate-binding protein that functions together with centralspindlin in late cytokinesis, thus highlighting the importance of glycosylation in this process.
Protein phosphatase 6 regulates mitotic spindle formation by controlling the T-loop phosphorylation state of Aurora A bound to its activator TPX2
Authors: Zeng Kang , Bastos Ricardo Nunes , Barr Francis A. , Gruneberg Ulrike
Published: December 2010

Many protein kinases are activated by a conserved regulatory step involving T-loop phosphorylation. Although there is considerable focus on kinase activator proteins, the importance of specific T-loop phosphatases reversing kinase activation has been underappreciated. We find that the protein phosphatase 6 (PP6) holoenzyme is the major T-loop phosphatase for Aurora A, an essential mitotic kinase. Loss of PP6 function by depletion of catalytic or regulatory subunits interferes with spindle formation and chromosome alignment because of increased Aurora A activity. Aurora A T-loop phosphorylation and the stability of the Aurora A–TPX2 complex are increased in cells depleted of PP6 but not other phosphatases. Furthermore, purified PP6 acts as a T-loop phosphatase for Aurora A–TPX2 complexes in vitro, whereas catalytically inactive mutants cannot dephosphorylate Aurora A or rescue the PPP6C depletion phenotype. These results demonstrate a hitherto unappreciated role for PP6 as the T-loop phosphatase regulating Aurora A activity during spindle formation and suggest the general importance of this form of regulation.
Local clustering of transferrin receptors promotes clathrin-coated pit initiation
Authors: Liu Allen P. , Aguet François , Danuser Gaudenz , Schmid Sandra L.
Published: December 2010

Clathrin-mediated endocytosis (CME) is the major pathway for concentrative uptake of receptors and receptor–ligand complexes (cargo). Although constitutively internalized cargos are known to accumulate into maturing clathrin-coated pits (CCPs), whether and how cargo recruitment affects the initiation and maturation of CCPs is not fully understood. Previous studies have addressed these issues by analyzing the global effects of receptor overexpression on CME or CCP dynamics. Here, we exploit a refined approach using expression of a biotinylated transferrin receptor (bTfnR) and controlling its local clustering using mono- or multivalent streptavidin. We show that local clustering of bTfnR increased CCP initiation. By tracking cargo loading in individual CCPs, we found that bTfnR clustering preceded clathrin assembly and confirmed that bTfnR-containing CCPs mature more efficiently than bTfnR-free CCPs. Although neither the clustering nor the related changes in cargo loading altered the rate of CCP maturation, bTfnR-containing CCPs exhibited significantly longer lifetimes than other CCPs within the same cell. Together these results demonstrate that cargo composition is a key source of the differential dynamics of CCPs.