bluuebunny/crossref_metadata_2025 huggingface dataset:
The information structure of Danish grammar constructions
Authors: Paggio Patrizia
Published: May 2009

This paper addresses the issue of how information structure can be accounted for in a formal grammar of Danish. Three information structure features – topic, focus and background – are discussed, and it is shown how they are instantiated in a number of different grammatical constructions from a corpus of spoken Danish. Prosodic, syntactic and information structure constraints characterising the various constructions are represented as typed feature structures following Head-driven Phrase Structure Grammar (HPSG), and the constructions themselves are ordered in a type hierarchy. The proposed approach modifies and extends earlier HPSG-based accounts by integrating information structure as a dimension of phrasal and clausal grammar constructions.
Linguistic Purism, Protectionism, and Nationalism in the Germanic Languages Today
Authors: McLelland Nicola
Published: May 2009

This paper re-examines the notions of “linguistic purism” and “linguistic nationalism” with respect to public discourses of language cultivation in recent years in a number of Germanic-speaking countries (Germany, the Netherlands, Sweden, Denmark, and, briefly, Norway). In particular, the paper considers domain protection and attitudes to spelling variability and spelling reform. While in Germany linguistic nationalism and linguistic purism meet in speaker attitudes towards loanwords and spelling reform, in other Germanic-speaking countries linguistic nationalism may also take different forms, and linguistic purism may have other targets and motivations.
Editorial A Glimpse of EU Government
Authors: JWS  , WTE
Published: May 2009

A glimpse of EU government

When president Sarkozy said, before the European Parliament on 16 December 2008, that the French presidency had allowed the European institutions to function at full capacity and successfully, he corrected a widely held image. The image, proffered in the media and in even better informed circles, was that he, Nicolas Sarkozy, happening into a repetition of crises which plunged him into his element, had personally gone around to solve one crisis after the other. According to Sarkozy himself, that was not the case. It was the European states, the Brussels institutions and the Parliament that had for once taken their responsibility and had acted.
The Dynamics of the European Union Legal Order: An Increasingly
Coherent Framework of Action and Interpretation
Authors: Wessel Ramses A.
Published: May 2009

Institutional and normative convergence – Common Foreign and Security
Policy – Pillar Structure – External Relations –
Role of the Court – Normative Consistency – EU Legal Order
– Legal Nature CFSP – Treaty of Lisbon – Legal
Instruments – Decision-Making
The Czech Republic: The Constitutional Court on the Lisbon Treaty Decision of 26 November 2008
Authors: Bříza Petr
Published: May 2009

On 26 November 2008 the Czech Constitutional Court (hereinafter Court) handed down a long-awaited opinion in which it unanimously found the Lisbon Treaty (hereinafter Treaty) to be compatible with the Czech constitutional order. The decision has drawn broad attention at all levels, be it political circles, academia or even general public. It is certainly one of the most significant decisions in the Court's history and it has EU-wide implications.
Ambulatory Assessment
Authors: Ebner-Priemer Ulrich W. , Trull Timothy J.
Published: May 2009

Convergent experimental data, autobiographical studies, and investigations on daily life have all demonstrated that gathering information retrospectively is a highly dubious methodology. Retrospection is subject to multiple systematic distortions (i.e., affective valence effect, mood congruent memory effect, duration neglect; peak end rule) as it is based on (often biased) storage and recollection of memories of the original experience or the behavior that are of interest. The method of choice to circumvent these biases is the use of electronic diaries to collect self-reported symptoms, behaviors, or physiological processes in real time. Different terms have been used for this kind of methodology: ambulatory assessment, ecological momentary assessment, experience sampling method, and real-time data capture. Even though the terms differ, they have in common the use of computer-assisted methodology to assess self-reported symptoms, behaviors, or physiological processes, while the participant undergoes normal daily activities. In this review we discuss the main features and advantages of ambulatory assessment regarding clinical psychology and psychiatry: (a) the use of realtime assessment to circumvent biased recollection, (b) assessment in real life to enhance generalizability, (c) repeated assessment to investigate within person processes, (d) multimodal assessment, including psychological, physiological and behavioral data, (e) the opportunity to assess and investigate context-specific relationships, and (f) the possibility of giving feedback in real time. Using prototypic examples from the literature of clinical psychology and psychiatry, we demonstrate that ambulatory assessment can answer specific research questions better than laboratory or questionnaire studies.
Ambulatory Assessment in Industrial/Organizational Psychology
Authors: Klumb Petra , Elfering Achim , Herre Christiane
Published: May 2009

In this review, we demonstrate the contribution of ambulatory assessment (AA) research to I/O psychology by reference to four dynamic phenomena, the investigation of which we judge to benefit most from the application of AA techniques: (a) work strain and coping with work stressors, (b) the work/nonwork interface, (c) social interactions at the workplace, and (d) job attitudes and work-related emotions. As we see it, the greatest potential of these studies lies in the analysis of how interindividual differences modulate intraindividual processes. After demonstrating the value of the method, we outline and discuss ways of tackling a number of methodological issues raised in the studies reviewed: selective participation and attrition, altered reporting behavior and reactivity, noncompliance with study instructions, low acceptance, and development of reduced scales or single-item measures. Future studies can pave the way for the broad acceptance and utilization of AA methods by contributing to the resolution of these issues.
The Vicissitudes of Conflict Measurement
Authors: Burk William J. , Denissen Jaap , Van Doorn Muriel D. , Branje Susan J.T. , Laursen Brett
Published: May 2009

This report examined the stability and reliability of self-reported conflict frequency in relationships with mothers, fathers, and best friends. Participants were drawn from three independent samples in the Netherlands (n = 72, M = 15.6 years), Germany (n = 242, M = 19.7 years), and the United States (n = 250, M = 19.8 years). Participants completed both topic-based surveys and interaction-based diary assessments of conflict frequency. Within samples, comparable levels of internal consistency and temporal stability emerged in each relationship for both assessment techniques. Topic-based and interaction-based assessments of conflict frequency were moderately correlated in each relationship within samples. Daily topic-based assessments with short intervals between time points may provide the most advantageous assessment strategy for obtaining reliable measures of conflict frequency in adolescents’ close relationships.
Ambulatory Assessment in Lifespan Psychology
Authors: Hoppmann Christiane A. , Riediger Michaela
Published: May 2009

Ambulatory assessment represents a powerful research tool in lifespan psychology because it allows assessing the within-person variability of developmental processes as it occurs within context-specific influences of people’s natural environments. Following a discussion of historical origins, we review four current research themes in developmentally relevant ambulatory assessment studies that use electronic devices as assessment instruments: (a) affective-motivational development, (b) social contexts of development, (c) age-related challenges and everyday functioning, and (d) cognitive development. Overall, the reviewed research demonstrates that ambulatory assessment complements traditional developmental study designs and laboratory assessments in important ways. Acknowledging the strengths and limitations of ambulatory assessment approaches, we propose that ambulatory assessment will benefit lifespan psychology most if it becomes an integral part of multimethod investigations of developmental phenomena that balance the external and internal validity of findings. Future research should strengthen the lifespan perspective in ambulatory assessment approaches, combine multiple indicators (subjective and objective) of successful development, and attend to the fact that individual development often interacts with significant others.
Exploring the Validity of Graphology with the Rorschach Test
Authors: Thiry Benjamin
Published: May 2009

Considered by some as a personality assessment technique, graphology is defended by its partisans but finds little solid scientific base. Our research (N = 45) compares the judgment of graphologists (k = 2) and 13 graphological variables with 13 variables of the Rorschach test according to the comprehensive system. The average reliability of graphologists’ judgments was .43. Their average validity was .05. Sixteen correlations were significant (p < .05) between graphological variables and Rorschach variables. Some are compatible with graphological theories. Others are random or difficult to understand. Great caution is essential in the isolated use of graphology as a personality assessment technique.
Rocket observations of two distinct types of dispersive features of auroral HF waves
Authors: Colpitts C. A. , Samara M. , LaBelle J. , Yoon P.
Published: May 2009

Two dispersive auroral HF emissions have been observed on two sounding rockets 5 years apart, employing different sensors with different effective antenna lengths and payload orientations. Both the SIERRA and CHARM rockets were launched to ∼735 km over active auroral substorms from Poker Flat, Alaska. On both flights, two distinct types of dispersed features occurred, each of which exhibited a frequency‐time structure characterized by an impulsive signal at one end of the frequency range, with progressively greater dispersion as the emission frequency approached a bounding frequency from either above or below. The first type of emissions, called “swishers,” occurred in the frequency range 1200–1500 kHz, with a characteristic signature whereby the signal is progressively more delayed as its frequency approaches a lower bound from above. The second type of emissions, called “hooks,” were observed in the frequency range 600–1100 kHz and were progressively more delayed as their frequency approached an upper bound from below. Qualitatively, hooks and swishers might both be explained purely by wave propagation: As the wave frequency approaches the lower cutoff of the Langmuir, O‐mode, or Z‐mode (in the case of swishers) or the upper cutoff of the whistler mode (in the case of hooks), the group velocity becomes small and the signals are delayed. In the case of hooks, ray‐tracing calculations support this explanation by showing that wave dispersion can explain the observed signature, if the emission originates on the whistler mode resonance cone on the 60° invariant field line. In the case of swishers, ray‐tracing calculations suggest that wave dispersion alone cannot explain the observed signature for any possible mode.
Recurrent CIR‐accelerated ions observed by STEREO SEPT
Authors: Gómez‐Herrero R. , Klassen A. , Müller‐Mellin R. , Heber B. , Wimmer‐Schweingruber R. , Böttcher S.
Published: May 2009

Fast solar wind streams originating from coronal holes interact with the preceding slow wind, leading to the formation of corotating interaction regions (CIRs) in the interplanetary medium. Near solar minimum CIR‐associated shocks become the dominant source of energetic ion increases observed near 1 AU in the energy range between some tens of keV/n and 10 MeV/n. Between March 2007 and February 2008, solar activity remained very low, and only a few minor solar energetic particle events were observed. Under these quiet conditions, recurrent CIR‐accelerated ion events were regularly observed by the Solar Electron and Proton Telescope (SEPT) on board the twin STEREO spacecraft. The increasing angular separation between STEREO‐A and STEREO‐B and observations available from near‐Earth spacecraft provide an excellent opportunity for multispacecraft analysis of the CIR‐associated particle events in the inner heliosphere during an extended period of low solar activity. The ion energy spectrum in the range of 0.6–2.2 MeV is characterized by a power law with spectral indices around 2.7. Below 0.6 MeV the spectrum is flatter and shows more variability. During near‐Earth periods, magnetospheric ion bursts contribute significantly to the observed intensities at low energies. Ballistic back mapping has been used to correlate multipoint in situ measurements and coronal synoptic maps. This made it possible to identify the parent coronal holes and to track the same stream for several consecutive rotations. Discrepancies in the structures and the spectra observed by different spacecraft for the same event are sometimes present. These deviations become more evident as the spatial separation between STEREO‐A and STEREO‐B increases. Coronal hole evolution, radial and latitudinal separation, and interactions between CIRs and interplanetary coronal mass ejections are found to be the main sources of these differences.
Indian Ocean intraseasonal sea surface temperature variability during boreal summer: Madden‐Julian Oscillation versus submonthly forcing and processes
Authors: Duncan Benét , Han Weiqing
Published: May 2009

Intraseasonal sea surface temperature (SST) variability in the Indian Ocean during boreal summer is investigated with a series of experiments using the Hybrid Coordinate Ocean Model (HYCOM). QuickSCAT winds and satellite‐observed outgoing longwave radiation (OLR) are used to identify the wind and convection patterns associated with atmospheric intraseasonal oscillations (ISOs). Effects of the Madden‐Julian Oscillation (MJO; 30–90 days) and submonthly ISOs are separately examined. Similar to winter, MJO forcing dominates summertime SST variability, even though submonthly forcing is stronger. Wind plays a much larger role in altering SSTs than either shortwave fluxes or precipitation. Different from winter cases, the maximum summertime SST variability shifts to the Arabian Sea (AS) and the Bay of Bengal (BOB), when ISOs also shift to the Northern Hemisphere. In the BOB, surface heat fluxes due to changes in wind speed have a stronger influence on SST than upwelling and advection induced by wind stress, whereas in winter, the effects of surface heat fluxes and oceanic upwelling and advection are comparable. This difference arises from the barrier layer and thin surface mixed layer in the BOB, which reduce the effects of upwelling and amplify the effects of surface heat fluxes. In the AS, surface heat fluxes and entrainment cooling due to changes in wind speed have a larger effect on MJO‐scale SST than upwelling induced by wind stress, while the two have comparable effects on submonthly SST. In the equatorial region, wind speed and stress are equally important.
An assessment of aerosol‐cloud interactions in marine stratus clouds based on surface remote sensing
Authors: McComiskey Allison , Feingold Graham , Frisch A. Shelby , Turner David D. , Miller Mark A. , Chiu J. Christine , Min Qilong , Ogren John A.
Published: May 2009

An assessment of aerosol‐cloud interactions (ACI) from ground‐based remote sensing under coastal stratiform clouds is presented. The assessment utilizes a long‐term, high temporal resolution data set from the Atmospheric Radiation Measurement (ARM) Program deployment at Pt. Reyes, California, United States, in 2005 to provide statistically robust measures of ACI and to characterize the variability of the measures based on variability in environmental conditions and observational approaches. The average ACIN (= dlnNd/dlnα, the change in cloud drop number concentration with aerosol concentration) is 0.48, within a physically plausible range of 0–1.0. Values vary between 0.18 and 0.69 with dependence on (1) the assumption of constant cloud liquid water path (LWP), (2) the relative value of cloud LWP, (3) methods for retrieving Nd, (4) aerosol size distribution, (5) updraft velocity, and (6) the scale and resolution of observations. The sensitivity of the local, diurnally averaged radiative forcing to this variability in ACIN values, assuming an aerosol perturbation of 500 cm−3 relative to a background concentration of 100 cm−3, ranges between −4 and −9 W m−2. Further characterization of ACI and its variability is required to reduce uncertainties in global radiative forcing estimates.
Changes in the predictability of the daily thermal structure in southern South America using information theory
Authors: Naumann Gustavo , Vargas Walter M.
Published: May 2009

Spatiotemporal behaviors of predictability of climate system were studied. These were analyzed as changes in persistence and system memory using information theory. This study was performed by coupling a cluster analysis algorithm and conditional entropy in southern South America. The spatial analysis of the entropy showed that a meridional gradient exists in the entire region, and its maximum is in the southern region. In this study, the gradients of this property in the northern regions yield predictabilities that are twice those in the southern part of South America. Temporal changes in conditional entropy were observed with quasi‐cyclical variations. The low frequency variability estimate in the conditional entropy indicates that the dominant wave is approximately 18 years. The changes observed in the persistence and conditional entropy, especially in groups that representing the warm and cold days, suggest that changes in objective forecasting are necessary.
High‐frequency P‐wave seismic noise driven by ocean winds
Authors: Zhang Jian , Gerstoft Peter , Shearer Peter M.
Published: May 2009

Earth's background vibrations at frequencies below about 0.5 Hz have been attributed to ocean‐wave energy coupling into the ground and propagating as surface waves and P‐waves (compressional waves deep within the Earth). However, the origin and nature of seismic noise on land at frequencies around 1 Hz has not yet been well studied. Using array beamforming, we analyze the seismic noise fields at two remote sites (Parkfield and the Mojave Desert) in California, for durations of one and six months respectively. We find that (1) the seismic background noise at about 0.6–2 Hz consists of a significant amount of continuous P‐waves originating offshore, and (2) the power of the P‐wave noise is highly correlated with the offshore wind speed, demonstrating that these high‐frequency P‐waves are excited by distant ocean winds. Our result suggests a land‐based seismological proxy for monitoring oceanic weather.
Hamilton–Jacobi theory in three-dimensional Minkowski space via Cartan geometry
Authors: Horwood Joshua T. , McLenaghan Raymond G. , Smirnov Roman G.
Published: May 2009

A complete solution to the problem of orthogonal separation of variables of the Hamilton–Jacobi equation in three-dimensional Minkowski space is obtained. The solution is based on the underlying ideas of Cartan geometry and ultimately developed into a general new algorithm that can be employed in the study of Hamiltonian systems defined by natural Hamiltonians within the framework of Hamilton–Jacobi theory. To demonstrate its effectiveness, we investigate from this viewpoint the Morosi–Tondo integrable system derived as a stationary reduction of the seventh-order Korteweg–de Vries flow to show explicitly that the system in question is an orthogonally separable Hamiltonian system. The latter result is a new characterization of the Morosi–Tondo system.
Hydrogen quantification in hydrogenated amorphous carbon films by infrared, Raman, and x-ray absorption near edge spectroscopies
Authors: Buijnsters J. G. , Gago R. , Jiménez I. , Camero M. , Agulló-Rueda F. , Gómez-Aleixandre C.
Published: May 2009

In this study, we have employed infrared (IR) absorption spectroscopy, visible Raman spectroscopy, and x-ray absorption near edge structure (XANES) to quantify the hydrogen (H) content in hydrogenated amorphous carbon (a-C:H) films. a-C:H films with a hydrogen content varying from 29 to 47 at. % have been synthesized by electron cyclotron resonance chemical vapor deposition at low substrate temperatures (<120 °C) applying a wide range of bias voltage, Vb, (−300 V<Vb<+100 V). With the application of high negative Vb, the a-C:H films undergo a dehydrogenation process accompanied by a sharp structural modification from polymer- to fullerenelike films. The trend in the H content derived from elastic recoil detection analysis (ERDA) is quantitatively reproduced from the intensity of the C–H bands and states in the IR and XANES spectra, respectively, as well as from the photoluminescence (PL) background drop in the Raman spectra. Using the H contents obtained by ERDA as reference data, semiquantitative expressions are inferred for the amount of bonded hydrogen as a function of the experimental spectroscopic parameters, i.e., the integrated area of the IR C–H stretching band at about 2900 cm−1, the PL background in visible Raman spectra, and the XANES intensity of the σ∗-CH peak.
Green luminescence of ZnS and ZnS:Cu quantum dots embedded in zeolite matrix
Authors: Nath S. S. , Chakdar D. , Gope G. , Kakati J. , Kalita B. , Talukdar A. , Avasthi D. K.
Published: May 2009

We report the synthesis of ZnS and ZnS:Cu (copper doped ZnS) quantum dots by chemical method at room temperature. In this technique ZnS and ZnS:Cu quantum dots are produced by simple chemical reactions where zeolite acts as matrix and plays the key role in controlling particle growth during synthesis. ZnS exhibits luminescence properties such as Zn2+ related emission. ZnS:Cu possesses Cu related emission, efficient low voltage electroluminescence, and super linear voltage-brightness electroluminescence characteristics. This study demonstrates the technological importance of semiconductor quantum dots prepared by low cost chemical route.
Collective branch regularization of simultaneous binary collisions in the 3D N-body problem
Authors: ElBialy Mohamed Sami
Published: May 2009

In this work we study simultaneous binary collision (SBC) singularities of M⩽N∕2 binaries in the three dimensional classical gravitational N-body problem. We show the following: (1) In the generalized Kustaanheimo–Stiefel variables, the totality of SBC orbits, the totality of simultaneous binary collisions (SBE) orbits, and the collision singularity itself together form a real analytic submanifold which we call the collision-ejection manifold. (2) We use the collision-ejection manifold to show geometrically, without writing down any power series, that SBC solutions can be collectively analytically continued. That is, all SBC orbits, not just a single orbit, can be written as a convergent power series in s=t1∕3 with coefficients that depend real analytically on initial conditions that lie in a real analytic submanifold. (3) There are two important ingredients in our work. (i) We use the intrinsic energies and properly rescaled intrinsic angular momenta of the binaries as variables in order to reduce the order of the singularity and to parametrize (distinguish between different) collision orbits that constitute the stable manifolds of the rest points that appear on the collision manifold in the McGehee coordinates. (ii) We use what we call the Kustaanheimo–Stiefel-projective transformation near a SBC singularity to resolve the singularity and isolate collision and ejection orbits from nearby near-collision and near-ejection orbits. We will see that quaternionic multiplication and quaternionic projective spaces are not suitable.
A novel mechanism for exciting intrinsic toroidal rotation
Authors: McDevitt C. J. , Diamond P. H. , Gürcan Ö. D. , Hahm T. S.
Published: May 2009

Beginning from a phase space conserving gyrokinetic formulation, a systematic derivation of parallel momentum conservation uncovers two physically distinct mechanisms by which microturbulence may drive intrinsic rotation. The first mechanism, which emanates from E×B convection of parallel momentum, has already been analyzed [O. D. Gurcan et al., Phys. Plasmas 14, 042306 (2007); R. R. Dominguez and G. M. Staebler, Phys. Fluids B 5, 3876 (1993)] and was shown to follow from radial electric field shear induced symmetry breaking of the spectrally averaged parallel wave number. Thus, this mechanism is most likely active in regions with steep pressure gradients or strong poloidal flow shear. The second mechanism uncovered, which appears in the gyrokinetic formulation through the parallel nonlinearity, emerges due to charge separation induced by the polarization drift. This novel means of driving intrinsic rotation, while nominally higher order in an expansion of the mode frequency divided by the ion cyclotron frequency, does not depend on radial electric field shear. Thus, while the magnitude of the former mechanism is strongly reduced in regions of weak radial electric field shear, this mechanism remains unabated and is thus likely relevant in complementary regimes.
Micro-Raman scattering of selenium-filled double-walled carbon nanotubes: Temperature study
Authors: Sendova Mariana , Datas Lucien , Flahaut Emmanuel
Published: May 2009

Selenium-filled double-walled carbon nanotubes (Se@DWNT) have been studied by high resolution transmission electron microscopy (HRTEM) and micro-Raman spectroscopy in the temperature interval from 80to600K employing 785nm excitation wavelength. The temperature dependences of the dominant bands (G-band and G′-band) are analyzed in terms of the model developed by Klemens [Phys. Rev. 148, 845 (1966)], Hart et al. [Phys. Rev. B 1, 638 (1970)], Cowley [J. Phys. (France) 26, 659 (1965)] and extended by Balkanski et al. [Phys. Rev. B 26, 1928 (1983)] for anharmonic decay of optical phonons. The findings were compared to analogous study for empty double-walled carbon nanotubes (DWNTs). The DWNT interatomic force constant modification as a result of the presence of the Se atoms inside the tubes is revealed through larger anharmonicity constants describing the temperature dependences of the G′-band and the inner tube tangential modes (G-band).
“Negative resistance” errors in four-point measurements of tunnel junctions and other crossed-wire devices
Authors: Pomeroy J. M. , Grube H.
Published: May 2009

“Negative resistance” errors due to nonuniform current distributions significantly distort the apparent electronic performance of devices formed with crossed wires, demonstrated here by resistance, magnetoresistance, current-voltage, and variable temperature measurements with and without corrections. Crossed-wire devices are frequently used in research settings for exploratory systems or rapid process recipe evolution due to the ease of depositing complete devices in situ through shadow masks. Unfortunately, this geometry suffers from a negative resistance effect that dominates the measurement when the device resistance is similar to or less than the wires’ resistance. We use a finite-element model and experimental data to extend work (by others) to quantify these errors when (1) devices are not square in shape, (2) when the two wires are not in the same resistivity, and (3) when the junction resistance is nonlinear in voltage. Using this knowledge and pre-existing analytical work, a straightforward method for correcting experimental measurements is suggested and evaluated. Finally, we illustrate the importance of correcting the data in magnetoresistance, current-voltage, and temperature dependent transport measurements for correct physical interpretation.
Impact response of nickel in the 150–1150 K temperature range
Authors: Zaretsky E. B.
Published: May 2009

Samples of polycrystalline nickel of high (99.9945%) and commercial (99.5%) purity were studied in a series of planar impact experiments with initial, preshot, sample temperature ranging from 150 to 1150 K. The free surface velocity of the impacted sample was monitored by velocity interferometer. On the base of the recorded waveforms, the temperature dependences of the dynamic tensile (spall) and the dynamic yield strength of the two kinds of nickel were determined. Both strength parameters of the two types of nickel decline gradually with temperature. The trend, however, is broken by strong anomalies of the yield strength near the Curie point of nickel, 630 K. While the yield strength of the high purity nickel shows a twofold increase over a narrow interval in close vicinity of the magnetic transformation, the strength of commercially pure material experiences, in the same temperature interval, a threefold drop approaching the strength level characteristic for high-purity nickel. The possible mechanisms of the observed phenomena are discussed.
Irreducible SU(3) Schwinger bosons
Authors: Anishetty Ramesh , Mathur Manu , Raychowdhury Indrakshi
Published: May 2009

We develop simple computational techniques for constructing all possible SU(3) representations in terms of irreducible SU(3) Schwinger bosons. We show that these irreducible Schwinger oscillators make SU(3) representation theory as simple as SU(2). The new Schwinger oscillators satisfy certain Sp(2,R) constraints and solve the multiplicity problem as well. These SU(3) techniques can be generalized to SU(N).
A new pressurizable dilatometer for measuring the time-dependent bulk modulus and pressure-volume-temperature properties of polymeric materials
Authors: Meng Yan , Bernazzani Paul , O’Connell Paul A. , McKenna Gregory B. , Simon Sindee L.
Published: May 2009

A new piston-cylinder-type pressurizable dilatometer controlled by a stepper motor has been developed to measure the time-dependent bulk modulus and pressure-volume-temperature (PVT) behavior of polymeric materials. The dilatometer can be operated from 35 to 230 °C and at pressures of up to 250 MPa. The sample cell, which contains the sample and a fluorinated oil as the confining fluid, is totally submerged into a high precision oil bath to achieve a temperature stability of better than 0.01 °C. The instrument is calibrated with mercury and quartz. The total instrument volume is 4.0 cm3, of which 2.3 cm3 is the sample cell; the total volume can be measured with an average absolute error of better than 5.0×10−4 cm3. To demonstrate the instrument’s capabilities, the time-dependent bulk modulus and the PVT behavior of a polystyrene are obtained and compared to the literature.
Influence of dc bias currents on Co/Cu/Co nonlocal spin valves
Authors: Wang X. J. , Zou H. , Ocola L. E. , Divan R. , Ji Y.
Published: May 2009

The spin signals of three Co/Cu/Co nonlocal spin valves have been measured as a function of a dc bias current. Both increases and decreases of spin signals have been observed. The increase in spin signal is attributed to the redistribution of the injection current at a high current density. A shift in effective injection point up to ∼100 nm is estimated. The decrease in spin signals is attributed to structural change of the materials and interfaces due to the prolonged exposure to a high-density current.
Compact models considering incomplete voltage swing in complementary metal oxide semiconductor circuits at ultralow voltages: A circuit perspective on limits of switching energy
Authors: Gupta Sumeet Kumar , Raychowdhury Arijit , Roy Kaushik
Published: May 2009

This paper presents a circuit perspective on complementary metal oxide semiconductor (CMOS) limits by analyzing a standard CMOS inverter driving a capacitive load at ultralow supply voltages. While the behavior of an inverter is well understood and modeled in the superthreshold region and for sufficiently high supply voltages in the subthreshold region, the analysis at ultralow supply voltages is different. In this region of operation, the voltage levels corresponding to logic “1” and logic “0” are not Vdd and Gnd, respectively. We model the incomplete voltage swing and show that the minimum supply voltage for a CMOS inverter (with pull-up and pull-down devices as ideal conventional metal oxide semiconductor field effect transistors) is, indeed, 2kT/q ln 2. The novelty of this approach lies in the fact that it gives an explicit mathematical relationship between the supply voltage and a measure of distinguishability of the binary states defined in terms of the expected voltage swing. The analysis shows that the minimum supply voltage corresponds to the state when the two states become completely indistinguishable. Further, we obtain a relationship between the switching energy and robustness of CMOS inverters and interconnects, valid for the entire range of supply voltages. This analysis also shows that a minimum supply voltage of 2kT/q ln 2 may not correspond to the fundamental energy dissipation of kT ln 2.
High field-effect mobility pentacene thin-film transistors with nanoparticle polymer composite/polymer bilayer insulators
Authors: Jang Yunseok , Lee Wi Hyoung , Park Yeong Don , Kwak Donghoon , Cho Jeong Ho , Cho Kilwon
Published: May 2009

High field-effect mobility organic thin-film transistors with nanoparticle polymer composite/polymer bilayer insulators were fabricated. A device composed of a polyvinylphenol (PVP) insulator filled with barium strontium titanate (BST) nanoparticles and coated with a thin polystyrene film was found to exhibit a field-effect mobility (1.2 cm2 V−1 s−1 for a pentacene device) and a field-induced current that are superior to those of devices with only a PVP insulator or a BST-filled PVP insulator. These improvements in the performance are due to an increase in the capacitance and a reduction in the interface roughness of the insulator.
Anticipating synchronization of a class of chaotic systems
Authors: Han Qi , Li Chuandong , Huang Tingwen
Published: May 2009

This paper studies the anticipating synchronization of a class of coupled chaotic systems. The asymptotic stability and exponential stability criteria for the involved error dynamical system are established by means of model transformation incorporated with Lyapunov–Krasovskii functional and linear matrix inequality. Based on the proposed stability conditions the coupling strength is then explicitly designed in terms of system parameters and anticipating time. Numerical simulations are presented to verify the theoretical results.
A generalized dressing approach for solving the extended KP and the extended mKP hierarchy
Authors: Liu Xiaojun , Lin Runliang , Jin Bo , Zeng Yunbo
Published: May 2009

A combination of dressing method and variation of constants as well as a formula for constructing the eigenfunction is used to solve the extended KP hierarchy, which is a hierarchy with one more series of time flow and based on the symmetry constraint of KP hierarchy. Similarly, extended mKP hierarchy is formulated and its zero-curvature form, Lax representation, and reductions are presented. Via gauge transformation, it is easy to transform dressing solutions of extended KP hierarchy to the solutions of extended mKP hierarchy. Wronskian solutions of extended KP and extended mKP hierarchies are constructed explicitly.
Lower limit to phonon thermal conductivity of disordered, layered solids
Authors: Hopkins Patrick E. , Piekos Edward S.
Published: May 2009

The minimum limit to the thermal conductivity of disordered, layered solids is studied by accounting for minimum scattering times and velocities from oscillations of atoms bound by different interatomic forces. The model developed in this work allows for quantification of changes in the lower limit to thermal conductivity in heavily disordered solids due to force differences arising from planar interfaces. This model sets a lower limit to recent data of thermal conductivity of WSe2 layered films, the data from which were below the lower limits predicted by previous models.
Toward photonic crystal based spatial filters with wide angle ranges of total transmission
Authors: Serebryannikov A. E. , Petrov A. Y. , Ozbay Ekmel
Published: May 2009

Spatial filters with steep switching between wide ranges of total transmission and total reflection can be obtained by using two-dimensional dielectric photonic crystals, which are a few wavelengths thick. The guidelines for engineering bandpass and bandstop filters are given. The flatness of isofrequency contours that are localized around a periphery point of the first Brillouin zone is a necessary but insufficient condition for the existence of wide angle ranges of total transmission at intermediate and large angles of incidence. Such ranges that are wider than 20° are demonstrated.
Theoretical investigation of A-element atom diffusion in Ti2AC (A=Sn, Ga, Cd, In, and Pb)
Authors: Liu B. , Wang J. Y. , Zhang J. , Wang J. M. , Li F. Z. , Zhou Y. C.
Published: May 2009

The phase stability and mechanical properties of Ti2AC (A=Ga, Cd, Sn, In, and Pb) have close relationship with the behavior of group-A element atoms in these compounds. This letter shows that although the Al, Ga, and In (or Si, Sn, and Pb) are in the same group, the migration energy and vacancy formation energy of group-A atom in Ti2GaC/Ti2InC (or Ti2SnC/Ti2PbC) are noticeable lower than those in Ti2AlC (or Ti3SiC2). The present results are helpful for a better understanding of easy out diffusion and self-extrusion of group-A atoms in these compounds.
Characterization of local electrical properties of polycrystalline silicon thin films and hydrogen termination effect by conductive atomic force microscopy
Authors: Machida Emi , Uraoka Yukiharu , Fuyuki Takashi , Kokawa Ryohei , Ito Takeshi , Ikenoue Hiroshi
Published: May 2009

We observed local electrical properties of polycrystalline silicon films by conductive atomic force microscopy. Moreover, we investigated the effects of hydrogen termination on the polycrystalline silicon films. Before hydrogen termination, conductive regions in grain disappeared with the repeated scanning of the cantilever, while conductive regions in grain boundary almost unchanged. It is considered that hopping conduction is a major electrical conduction mechanism at grain boundaries. After 5 min hydrogen termination, locally nonterminated regions were observed near grain boundaries. This suggests that hydrogen termination of the polycrystalline silicon does not randomly progress, and there are regions that cannot be easily inactivated near grain boundaries.
Temperature dependence of time-resolved photoluminescence spectroscopy in InAs/GaAs quantum ring
Authors: Lin C. H. , Lin H. S. , Huang C. C. , Su S. K. , Lin S. D. , Sun K. W. , Lee C. P. , Liu Y. K. , Yang M. D. , Shen J. L.
Published: May 2009

We present detailed experimental results of the temperature dependence of continuous wave and time-resolved photoluminescence (PL) spectroscopy in self-assembled InAs/GaAs quantum dot and quantum ring nanostructures. A dramatic increase in PL decay time of the excited and ground states is observed in InAs quantum rings at high temperature. We speculate that the longer PL lifetime in quantum rings is due to the interplay among the dark states, ground states, and the reduced wave function overlapping between electrons and holes. A rate equation model is proposed to interpret the observed temperature dependence of the ground state exciton lifetime.
Electric field tunable 60 GHz ferromagnetic resonance response in barium ferrite-barium strontium titanate multiferroic heterostructures
Authors: Song Young-Yeal , Das Jaydip , Krivosik Pavol , Mo Nan , Patton Carl E.
Published: May 2009

A magnetic-ferroelectric film heterostructure with a large electric field tuning of the ferromagnetic resonance (FMR) mode was fabricated. Pulse laser deposited 30 nm thick Pt electrodes and 3 μm thick barium strontium titanate films on Nb-doped strontium titanate substrates were capped with an unbonded 200 μm thick single crystal in-plane c-axis barium hexaferrite slab. The structure gives a 60 GHz FMR frequency shift of 16 MHz at a bias of 29 V, for an average response of 0.55 MHz/V. The maximum incremental tuning response at 29 V was 1.3 MHz/V. This is a hundredfold improvement over previous results.
Medical physics standardizes clinical training
Authors: Feder Toni
Published: May 2009

Public safety is the motivation behind new requirements for becoming certified as a medical physicist.
Vast underestimation of Madagascar's biodiversity evidenced by an integrative amphibian inventory
Authors: Vieites David R. , Wollenberg Katharina C. , Andreone Franco , Köhler Jörn , Glaw Frank , Vences Miguel
Published: May 2009

Amphibians are in decline worldwide. However, their patterns of diversity, especially in the tropics, are not well understood, mainly because of incomplete information on taxonomy and distribution. We assess morphological, bioacoustic, and genetic variation of Madagascar's amphibians, one of the first near-complete taxon samplings from a biodiversity hotspot. Based on DNA sequences of 2,850 specimens sampled from over 170 localities, our analyses reveal an extreme proportion of amphibian diversity, projecting an almost 2-fold increase in species numbers from the currently described 244 species to a minimum of 373 and up to 465. This diversity is widespread geographically and across most major phylogenetic lineages except in a few previously well-studied genera, and is not restricted to morphologically cryptic clades. We classify the genealogical lineages in confirmed and unconfirmed candidate species or deeply divergent conspecific lineages based on concordance of genetic divergences with other characters. This integrative approach may be widely applicable to improve estimates of organismal diversity. Our results suggest that in Madagascar the spatial pattern of amphibian richness and endemism must be revisited, and current habitat destruction may be affecting more species than previously thought, in amphibians as well as in other animal groups. This case study suggests that worldwide tropical amphibian diversity is probably underestimated at an unprecedented level and stresses the need for integrated taxonomic surveys as a basis for prioritizing conservation efforts within biodiversity hotspots.
Top marine predators track Lagrangian coherent structures
Authors: Tew Kai Emilie , Rossi Vincent , Sudre Joel , Weimerskirch Henri , Lopez Cristobal , Hernandez-Garcia Emilio , Marsac Francis , Garçon Veronique
Published: May 2009

Meso- and submesoscales (fronts, eddies, filaments) in surface ocean flow have a crucial influence on marine ecosystems. Their dynamics partly control the foraging behavior and the displacement of marine top predators (tuna, birds, turtles, and cetaceans). In this work we focus on the role of submesoscale structures in the Mozambique Channel in the distribution of a marine predator, the Great Frigatebird. Using a newly developed dynamic concept, the finite-size Lyapunov exponent (FSLE), we identified Lagrangian coherent structures (LCSs) present in the surface flow in the channel over a 2-month observation period (August and September 2003). By comparing seabird satellite positions with LCS locations, we demonstrate that frigatebirds track precisely these structures in the Mozambique Channel, providing the first evidence that a top predator is able to track these FSLE ridges to locate food patches. After comparing bird positions during long and short trips and different parts of these trips, we propose several hypotheses to understand how frigatebirds can follow these LCSs. The birds might use visual and/or olfactory cues and/or atmospheric current changes over the structures to move along these biologic corridors. The birds being often associated with tuna schools around foraging areas, a thorough comprehension of their foraging behavior and movement during the breeding season is crucial not only to seabird ecology but also to an appropriate ecosystemic approach to fisheries in the channel.
The tumor suppressor WTX shuttles to the nucleus and modulates WT1 activity
Authors: Rivera Miguel N. , Kim Woo Jae , Wells Julie , Stone Amanda , Burger Alexa , Coffman Erik J. , Zhang Jianmin , Haber Daniel A.
Published: May 2009

WTX
encodes a tumor suppressor gene inactivated in Wilms tumor and recently implicated in WNT signaling through enhancement of cytoplasmic β-catenin (CTNNB1) degradation. Here, we report that WTX translocates to the nucleus, a property that is modified by an endogenous splicing variant and is modulated by a nuclear export inhibitor. WTX is present in distinct subnuclear structures and co-localizes with the paraspeckle marker p54NRB/NONO, suggesting a role in transcriptional regulation. Notably, WTX binds WT1, another Wilms tumor suppressor and stem cell marker that encodes a zinc-finger transcription factor, and enhances WT1-mediated transcription of
Amphiregulin
, an endogenous target gene. Together, these observations suggest a role for WTX in nuclear pathways implicated in the transcriptional regulation of cellular differentiation programs.
Historical invasions of the intertidal zone of Atlantic North America associated with distinctive patterns of trade and emigration
Authors: Brawley Susan H. , Coyer James A. , Blakeslee April M. H. , Hoarau Galice , Johnson Ladd E. , Byers James E. , Stam Wytze T. , Olsen Jeanine L.
Published: May 2009

Early invasions of the North American shore occurred mainly via deposition of ballast rock, which effectively transported pieces of the intertidal zone across the Atlantic. From 1773–1861, >880 European ships entered Pictou Harbor, Nova Scotia, as a result of emigration and trade from Europe. The rockweedFucus serratus(1868) and the snailLittorina littorea(≈1840) were found in Pictou during this same period. With shipping records (a proxy for propagule pressure) to guide sampling, we usedF. serratusas a model to examine the introductions because of its relatively low genetic diversity and dispersal capability. Microsatellite markers and assignment tests revealed 2 introductions of the rockweed into Nova Scotia: 1 from Galway (Ireland) to Pictou and the other from Greenock (Scotland) to western Cape Breton Island. To examine whether a high-diversity, high-dispersing species might have similar pathways of introduction, we analyzedL. littorea, using cytochromebhaplotypes. Eight of the 9 Pictou haplotypes were found in snails collected from Ireland and Scotland. Our results contribute to a broader understanding of marine communities, because these 2 conspicuous species are likely to be the tip of an “invasion iceberg” to the NW Atlantic from Great Britain and Ireland in the 19th Century.
Mechanism of procaspase-8 activation by c-FLIP
L
Authors: Yu Jong W. , Jeffrey Philip D. , Shi Yigong
Published: May 2009

Cellular FLICE-inhibitory protein (c-FLIP
L
) is a key regulator of the extrinsic cell death pathway. Although widely regarded as an inhibitor of initiator caspase activation and cell death, c-FLIP
L
is also capable of enhancing procaspase-8 activation through heterodimerization of their respective protease domains. However, the underlying mechanism of this activation process remains enigmatic. Here, we demonstrate that cleavage of the intersubunit linker of c-FLIP
L
by procaspase-8 potentiates the activation process by enhancing heterodimerization between the two proteins and vastly improving the proteolytic activity of unprocessed caspase-(C)8. The crystal structures of the protease-like domain of c-FLIP
L
alone and in complex with zymogen C8 identify the unique determinants that favor heterodimerization over procaspase-8 homodimerization, and induce the latent active site of zymogen C8 into a productive conformation. Together, these findings provide molecular insights into a key aspect of c-FLIP
L
function that modulates procaspase-8 activation to elicit diverse responses in different cellular contexts.