bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of the CALIPSO‐CALIOP extinction coefficients from in situ observations in midlatitude cirrus clouds during the CIRCLE‐2 experiment
Authors: Mioche Guillaume , Josset Damien , Gayet Jean‐François , Pelon Jacques , Garnier Anne , Minikin Andreas , Schwarzenboeck Alfons
Published: June 2010

This paper presents a comparison of combined Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP) extinction retrievals with airborne lidar and in situ cirrus cloud measurements. Specially oriented research flights were carried out in western Europe in May 2007 during the Cirrus Cloud Experiment (CIRCLE‐2) with the German Deutsches Zentrum für Luft‐ und Raumfahrt (DLR) and the French Service des Avions Français Instrumentés pour la Recherche en Environnement (SAFIRE) Falcon aircraft equipped for remote and in situ measurements, respectively. Four cirrus cloud situations including thin cirrus layers and outflow cirrus linked to midlatitude fronts and convective systems were chosen to perform experimental collocated observations along the satellite overpasses. The measurements were carried out with temperatures ranging between −38°C and −60°C and with extinction coefficients no larger than 2 km−1. Comparisons between CALIOP and airborne lidar (LEANDRE New Generation (LNG)) attenuated backscatter coefficients reveal much larger CALIOP values for one frontal cirrus situation which could be explained by oriented pristine ice crystals. During the four selected cases the CALIOP cirrus extinction profiles were compared with in situ extinction coefficients derived from the Polar Nephelometer. The results show a very good agreement for two situations (frontal and outflow cases) despite very different cloud conditions. The slope parameters of linear fittings of CALIOP extinction coefficients with respect to in situ measurements are 0.90 and 0.94, with correlation coefficients of 0.69 and only 0.36 for the latter case because of a small number of measurements. On the contrary, significant differences are evidenced for two other situations. In thin frontal cirrus at temperatures ranging between −58°C and −60°C, systematic larger CALIOP extinctions can be explained by horizontally oriented ice crystals with prevalent planar‐plate shape as revealed by the Cloud Particle Imager instrument. This nicely explains the disagreements between CALIOP and LNG observations for that case. For the last cirrus situation related to dense outflow cirrus, CALIOP extinctions are systematically lower than the in situ observations. No clear explanations can be drawn to assess this feature, but the shattering of ice crystals on probe tips may enhance the measured extinction because numerous large ice crystals are observed during this cirrus situation. Finally, relationships between the ice water content and the extinction coefficient, the effective diameter, and the temperature are determined from this in situ measurements data set.
Inception of stream incision by seepage erosion
Authors: Pornprommin A. , Izumi N.
Published: June 2010

Because seepage erosion is generated by complex interactions with other processes, associated stream incision process is not well understood. In this study, some fundamental characteristics of incipient incision by seepage erosion were investigated by laboratory experiments and linear stability analysis. The experiments were conducted with various sediment layer depths and gradients. With similar discharges in the experiments, incision spacing decreases with increasing depth of the sediment layer and with increasing gradient, whereas incision width increases with increasing sediment layer depth. A linear stability analysis was performed using the Dupuit‐Forchheimer equation and an expression of the planimetric retreat of the scarp. The retreat velocity of the scarp consists of two terms: (1) a power law function that describes the specific discharge in excess of a critical discharge and (2) a diffusion‐like function that describes the incision edge shapes, in which the retreat rate is enhanced or reduced by the convexity and concavity of the edges, respectively. This analysis shows that the characteristic incision spacing becomes infinitely small when the effect of the edge shapes is excluded. Using the experimental data of incision spacings, the values of the diffusion‐like coefficient in the second term were estimated. Since the weight of a failure block and hydraulic pressure are the driving forces in the slope stability analysis, a relationship was found between the diffusion‐like coefficient and the combination of the two forces.
Origin of coarsely crystalline gypsum domes in a saline playa environment at the White Sands National Monument, New Mexico
Authors: Szynkiewicz Anna , Moore Craig H. , Glamoclija Mihaela , Bustos David , Pratt Lisa M.
Published: June 2010

Dome‐like structures up to 3 m in height, composed predominantly of coarse crystals of selenite gypsum, occur on the surface of Alkali Flat, a saline playa lake in White Sands National Monument, New Mexico. The structures were investigated using field observations, aerial images, and geochemical methods. The domes are inferred to be remnants of lake sediments that have been preserved from Holocene eolian erosion due to higher cementation resulting from crystallization of large gypsum (selenite) crystals in the playa's clay‐rich sediments. Low δ2H values of the selenite, from −90 to −69 ‰, suggest precipitation from saturated solutions associated with groundwater seepage in the playa related to the upward flows of groundwater, primarily fed by meteoric water rather than the evaporation of the playa water. Values of δ34S for selenite range from 12.1 to 13.8 ‰ (median 13.0 ‰) and are notably higher than the dissolved sulfate in the modern groundwater system that has δ34S values from 10.2 to 11.8 ‰ (median 11.4 ‰). The two main regional sources of sulfate are Middle Permian evaporites with median δ34S values of 12.0 ‰ and Lower Permian evaporites with median δ34S values of 13.0 ‰. The δ34S values measured in domes suggest their formation during a period of time when groundwater seepage might have been dominated by deeply circulating water that interacted with Lower Permian evaporites buried in the basin center. The apparent alignments of domes suggest that past groundwater seepage was controlled by fractures beneath Alkali Flat which are associated with a regional fault system in the area.
From nappe stacking to out‐of‐sequence postcollisional deformations: Cretaceous to Quaternary exhumation history of the SE Carpathians assessed by low‐temperature thermochronology
Authors: Merten S. , Matenco L. , Foeken J. P. T. , Stuart F. M. , Andriessen P. A. M.
Published: June 2010

Apatite fission track (AFT) and (U‐Th)/He (AHe) thermochronology have been combined to constrain the exhumation history of the SE Carpathians. Cooling ages generally decrease from Cretaceous for the internal basement nappes (AFT ages), to Miocene–Quaternary (AFT and AHe, respectively) for the external sedimentary wedge. The AFT and AHe data show a Paleogene age cluster, which confirms a suspected but never demonstrated tectonic event. The new data furthermore suggest that the SE Carpathians have been affected by a middle Miocene exhumation phase related to continental collision, which occurred at rates of ∼0.8 mm/yr, similar to the one previously inferred for the East Carpathians. The SE Carpathian tectonic evolution, however, is overprinted by two younger exhumation events in the Pliocene–Pleistocene. The first exhumation phase (latest Miocene–early Pliocene) occurred at high exhumation rates (∼1.7 mm/yr) and is interpreted as a tectonic event and/or associated with a sea level drop in the Paratethys basins during the Messinian low stand. The youngest recorded tectonic phase suggests rapid Pleistocene exhumation (∼1.6 mm/yr) and is interpreted to represent crustal‐scale shortening different in mechanics from collisional processes. The data suggest that the SE Carpathians did not develop as a typical double‐vergent orogenic wedge; instead, exhumation was related to a foreland‐vergent sequence of nappe stacking during collision and was subsequently followed by a large out‐of‐sequence shortening event truncating the already locked collisional boundary.
Rare gases in lavas from the ultraslow spreading Lena Trough, Arctic Ocean
Authors: Nauret F. , Moreira M. , Snow J. E.
Published: June 2010

Mid‐ocean ridge basalts (MORB) from the Arctic Ocean have been much less studied than those from the Indian, Atlantic, and Pacific due to the difficulty of access related to ice cover. In 2001 and 2004 the Arctic ridges (Gakkel Ridge and Lena Trough) were intensively sampled. In this study we present the first helium, neon, and argon concentrations and isotopic ratios in a suite of samples from the ultraslow spreading Lena Trough (∼0.75 cm/yr effective full rate). Central Lena Trough (CLT) lavas display 4He/3He between 89,710 and 97,530 (R/Ra between 7.4 and 8.1), similar to the mean MORB ratio of 90,000 ± 10,000 (R/Ra = 8 ± 1). In a three neon isotope diagram, the samples fall on the MORB line, without showing any excess of nucleogenic 21Ne. The 40Ar/36Ar ratios vary from 349 to 6964. CLT samples have a typical MORB He and Ne isotopic composition. Rare gases do not indicate any mantle heterogeneities or contribution of subcontinental lithospheric mantle, although this has been suggested previously on the basis of the Sr‐Nd and Pb isotopic systems. Based on noble gas systematics, a DUPAL‐like anomaly is not observed in the Arctic Ocean. We propose two possible models which reconcile the rare gases with these previous studies. The first is that the Lena Trough mantle has a marble cake structure with small‐scale heterogeneities (<1 km), allowing rapid diffusion and homogenization of rare gases compared to elements such as Sr, Nd, and Pb. The second model proposes that the recycled component identified by other isotopic systems was fully degassed at a recent date. It would therefore have a negligible mass budget of rare gases compared to other isotopic systems. This would suggest that the mantle enrichment beneath Lena Trough was generated by rift‐forming processes and not by recycling.
Intermolecular phosphotransfer is crucial for efficient catalytic activity of nucleoside diphosphate kinase
Authors: Dar Haider Hussain , Chakraborti Pradip K.
Published: June 2010

NDK (nucleoside diphosphate kinase) is primarily involved in maintaining cellular nucleotide pools in both prokaryotes and eukaryotes. We cloned ndk from Salmonella typhimurium and expressed it in Escherichia coli as a histidine-tagged protein. The Ni-NTA (Ni2+-nitrilotriacetate)-purified protein (sNDK) was found to be tetrameric with a monomeric unit molecular mass of ~18 kDa. The sNDK exhibited bivalent-cation-dependent autophosphorylation at a wide range of pH values and the phosphorylation withstands acid or alkali treatment. Surprisingly, nucleoside diphosphates did not behave as ‘true inhibitors’ of autophosphorylation activity. The sNDK displayed phosphotransfer activity from nucleoside triphosphates to nucleoside diphosphates; however, it was Mg2+/Mn2+-dependent. Mutational analysis established His117 as the predominantly phosphorylating residue in sNDK. Although it is a histidine kinase, we found that substitution of Ser119 with alanine/glutamate significantly affected the autophosphorylation, as well as the NTP-synthesizing ability of sNDK. Interestingly, the mixture of inactive (H117A) and partially active (S119A) proteins was found to be catalytically more efficient than the presence of corresponding amounts of active population, advocating transfer of phosphate from phospho-His117 to Ser119. Consistent with this observation, the Ni-NTA-purified H117A protein, obtained following co-expression of both of the mutant constructs [His-tagged H117A and GST (glutathione transferase)-tagged S119A] in E. coli, exhibited autophosphorylation, thereby alluding to intermolecular phosphotransfer between His117 and Ser119. Although this housekeeping enzyme has long been discovered and characterized from different sources, the results of the present study portray how Ser119 in sNDK is phosphorylated. Furthermore, our findings illustrate for the first time that the intermolecular phosphotransfer is mandatory for the efficient NTP synthesis in any NDK.
Left-handed and right-handed one-way edge modes in a gyromagnetic photonic crystal
Authors: He Cheng , Chen Xiao-Lin , Lu Ming-Hui , Li Xue-Feng , Wan Wei-Wei , Qian Xiao-Shi , Yin Ruo-Cheng , Chen Yan-Feng
Published: June 2010

We theoretically reveal that a two-dimensional magneto-optical photonic crystal shows two pairs of one-way edge Dirac cones, whereby only clockwise and anticlockwise circle wave scattering (facing the direction of external applied magnetic field) are allowed in the second and third band-gaps, respectively. These two different chiral pathways originate from the different exchange of Chern numbers, which are attributed to the broken time-reversal symmetry. Moreover, below and above the edge Dirac point, the edge modes show the left-handed (counter propagation of group velocity and phase velocity) and right-handed characters, respectively.
Soliton solutions and quasiperiodic solutions of modified Korteweg–de Vries type equations
Authors: Geng Xianguo , Xue Bo
Published: June 2010

A hierarchy of new nonlinear evolution equations which contains the modified Korteweg–de Vries equation is proposed. With the aid of the inverse scattering transformation, N-soliton solutions of the first two nonlinear evolution equations in this hierarchy are derived. Based on the theory of algebraic curve, the corresponding flows are straightened under the Abel–Jacobi coordinates. The meromorphic function ϕ and the hyperelliptic curve Kn are introduced by which quasiperiodic solutions of the first two nonlinear evolution equations are constructed according to the asymptotic properties and the algebrogeometric characters of ϕ and Kn.
Characterization of diamond-like nanocomposite thin films grown by plasma enhanced chemical vapor deposition
Authors: Santra T. S. , Liu C. H. , Bhattacharyya T. K. , Patel P. , Barik T. K.
Published: June 2010

Diamond-like nanocomposite (DLN) thin films, comprising the networks of a-C:H and a-Si:O were deposited on pyrex glass or silicon substrate using gas precursors (e.g., hexamethyldisilane, hexamethyldisiloxane, hexamethyldisilazane, or their different combinations) mixed with argon gas, by plasma enhanced chemical vapor deposition technique. Surface morphology of DLN films was analyzed by atomic force microscopy. High-resolution transmission electron microscopic result shows that the films contain nanoparticles within the amorphous structure. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) were used to determine the structural change within the DLN films. The hardness and friction coefficient of the films were measured by nanoindentation and scratch test techniques, respectively. FTIR and XPS studies show the presence of CC, CH, SiC, and SiH bonds in the a-C:H and a-Si:O networks. Using Raman spectroscopy, we also found that the hardness of the DLN films varies with the intensity ratio ID/IG. Finally, we observed that the DLN films has a better performance compared to DLC, when it comes to properties like high hardness, high modulus of elasticity, low surface roughness and low friction coefficient. These characteristics are the critical components in microelectromechanical systems (MEMS) and emerging nanoelectromechanical systems (NEMS).
Correlation between corrosion performance and surface wettability in ZrTiCuNiBe bulk metallic glasses
Authors: Wang Y. B. , Li H. F. , Zheng Y. F. , Wei S. C. , Li M.
Published: June 2010

The corrosion properties of two Zr-based bulk metallic glass, Zr41Ti14Cu12Ni10Be23 (LM1) and Zr44Ti11Cu10Ni10Be25 (LM1b) were investigated by electrochemical measurements in simulated body fluid with pH value 7.4. With much lower current density and higher impedance values, as well as higher pitting potential, LM1b showed superior corrosion resistance to LM1. Under identical sample preparation and testing conditions, the difference in corrosion performance is found to relate closely to their surface wettability difference, as contact angle tests showed that LM1b is more hydrophobic than LM1. The excess free volume was measured and found having a close correlation with the wettability or the surface energy.
Time resolved studies of catastrophic optical mirror damage in red-emitting laser diodes
Authors: Elliott Stella N. , Smowton Peter M. , Ziegler Mathias , Tomm Jens W. , Zeimer Ute
Published: June 2010

We have observed the changing light intensity during catastrophic optical mirror damage (COMD) on the timescale of tens of nanoseconds using red-emitting AlGaInP quantum well based laser diodes. Using as-cleaved facets and this material system, which is susceptible to COMD, we recorded the drop in light intensity and the area of damage to the facet, as a function of current, for single, high current pulses. We found that in the current range up to 40 A, the total COMD process up to the drop of light intensity to nonlasing levels takes place on a timescale of hundreds of nanoseconds, approaching a limiting value of 200 ns, and that the measured area of facet damage showed a clear increase with drive current. Using a straightforward thermal model, we propose an explanation for the limiting time at high currents and the relationship between the time to COMD and the area of damaged facet material.
Time-dependent three-dimensional domain reverse mechanism in nucleation, growth, and breakdown of ferroelectric films
Authors: Shi Y. P. , Hong L. , Soh A. K.
Published: June 2010

A three-dimensional domain reversal and growth mechanism in ferroelectrics has been proposed based on domain shape evolution analysis, which can also be used to study the ferroelectric domain breakdown (FDB) phenomenon initialized by a high inhomogeneous electric field. It has been found that the aspect ratio of critical conic nucleus remained unchanged in the nucleation stage, and it abruptly decreased to an equilibrium value during the formation stage of the depolarization field, where ferroelectrics began to maintain a saturation domain radius. Consequently, the reverse domain would breakdown in a cylinder-shaped mode. Moreover, LiNbO3 ferroelectrics were found to possess the lowest critical tip voltage to cause FDB compared with other ferroelectrics.
Low loss high dielectric permittivity of polyvinylidene fluoride and KxTiyNi1−x−yO (x=0.05, y=0.02) composites
Authors: Bhadra Debabrata , Biswas A. , Sarkar S. , Chaudhuri B. K. , Tseng K. F. , Yang H. D.
Published: June 2010

Homogeneous thick film (∼0.10 mm) of high dielectric K0.05Ti0.02Ni0.93O; abbreviated as KTNO/polyvinylidene fluoride (PVDF) composite has been prepared by hot-molding technique. The frequency and temperature dependent dielectric behavior of this composite has been studied by varying the KTNO volume fraction (fKTNO). Near the percolation threshold (fKTNO=0.40), a large enhancement of effective dielectric permittivity (εeff∼400 which is 40 times higher than that of pure PVDF) with low loss (∼0.20 at 1 kHz) is observed. The experimental εeff data have been fitted with different theoretical models and found to follow percolation theory successfully. Such a high εeff and low loss flexible dielectric material appears to be suitable for technological applications.
Magnetization reversal in an individual 25 nm iron-filled carbon nanotube
Authors: Banerjee Palash , Wolny F. , Pelekhov D. V. , Herman M. R. , Fong K. C. , Weissker U. , Mühl T. , Obukhov Yu. , Leonhardt A. , Büchner B. , Hammel P. Chris
Published: June 2010

The magnetization reversal and switching behavior of an individual Fe-filled carbon nanotube has been measured using vibrating cantilever magnetometry. We report measurements of the magnetic field at which the 25 nanometer diameter iron core inside the nanotube reverses. The fields at which reversal occurs, characterized by an exceptionally narrow distribution (σH≤1 G at 6.3 K), are determined by thermally activated excitation over a field dependent barrier. The high precision achievable by virtue of measuring individual nanowires allows detailed quantitative understanding of magnetization reversal.
The low-lying states of the scandium dimer
Authors: Camacho Cristopher , Witek Henryk A. , Cimiraglia Renzo
Published: June 2010

A systematic investigation of low-lying states of Sc2 using multireference perturbation theory (NEVPT2 and NEVPT3) indicates that the ground state of this system is Σ5u− with re=2.611 Å, ωe=241.8 cm−1, and De=1.78 eV. This state is closely followed by other low-lying states of Sc2: Σ3u−, Δ5u, Π3g, Π1g, and Σ1u−. Our energy ordering of the Σ5u− and Σ3u− states confirms the recent MRCI results of Kalemos et al. [J. Chem. Phys. 132, 024309 (2010)] and is at variance with the earlier diffusion Monte Carlo predictions of Matxain et al. [J. Chem. Phys. 128, 194315 (2008)]. An excellent agreement between the second- and third-order NEVPT results and between the computed and experimental values of ωe (241.8 versus 238.9 cm−1) for the Σ5u− state suggests high accuracy of our predictions.
Magnetized plasma flows and magnetoplasmadynamic thrusters
Authors: Andreussi T. , Pegoraro F.
Published: June 2010

An axisymmetric magnetohydrodynamics (MHD) model of the acceleration channel of an applied-field magnetoplasmadynamic thruster is presented. A set of general relationships between the flow features and the thruster performance is obtained. The boundary conditions and the flow regime, which depends on the Alfvén Mach number, are shown to provide the ideal limits of steady state thruster operation. In the present analysis, a Hamiltonian formulation of the MHD plasma flow model is adopted. This formulation makes it possible to cast the model equations in a variational form, which is then solved by using a finite element numerical algorithm.
Potential and life cycle assessment of biodiesel production in China
Authors: Guo Rui , Hanaki Keisuke
Published: June 2010

Potential biodiesel production was evaluated by assuming that waste and cutover forestlands and burnt site areas, equivalent to 5.94% of China’s land area, were used to cultivate the most suitable energy crop in each province of China. Jatropha, Xanthoceras, Pistacia, and Swida were the candidate energy crops in that order of priority based on yield and oil content. The crop was assigned by comparing crop climatic requirements and the meteorological statistics of each province and choosing the best match. Potential production for all of China was estimated to be 57.6×106 tons/yr on the basis of seed yields and biodiesel conversion factors. A logistics scenario was created for the transportation of crops and biodiesel, and a life cycle analysis of greenhouse gas (GHG) emissions and costs were evaluated for the cultivation, refinement, and transportation stages using local data on energy sources and costs. The production of biodiesel with and without waste biomass utilization creates emissions of 0.95 and 1.31 t CO2eq/t biodiesel, respectively, as compared to 2.08 t CO2eq/t fossil diesel. Fertilizer use in the cultivation stage accounts for 61% and 44% of GHG emissions with and without waste biomass utilization, respectively. The use of waste biomass and proper use of fertilizers are essential in reducing GHG emissions and enhancing the advantages of using biodiesel.
Electric modulus-based analysis of the dielectric relaxation in carbon black loaded polymer composites
Authors: Belattar J. , Graça M. P. F. , Costa L. C. , Achour M. E. , Brosseau C.
Published: June 2010

A thorough investigation of the ac electrical properties of carbon black (CB) mixed into ethylene butylacrylate copolymer has been conducted using ac impedance spectroscopy in the frequency range 10 Hz–100 kHz and over the temperature range of 150 (Tg−48 K)–319 (Tg+121 K) K. For this investigation, a series of eight samples were prepared with various filler contents above the percolation threshold. Using the electric modulus formalism it has been found that the Cole–Cole equation of dielectric relaxation expressed in the electric modulus form is capable of quantitatively describing the experimental data from which we extract the relaxation time and a parameter α which gauges the broadening of the loss spectrum. The small values of α ranging from 0.06 to 0.10 suggest a behavior close to the state of a single relaxation time. Furthermore, the relaxation time as a function of temperature is characterized by an Arrhenius behavior. While the effective activation energy is on the order of 60 meV and is insensitive to CB volume fraction, the Arrhenius prefactor is found to strongly depend on this volume fraction. The observed relaxation mechanism does not result simply from thermally activated dipolar interactions but is a collective cooperative effect of the CB mesostructure.
Fabrication and visible emission of single-crystal diameter-modulated gallium phosphide nanochains
Authors: Fu Lu-Tang , Chen Zhi-Gang , Zou Jin , Cong Hong-Tao , (Max) Lu Gao-Qing
Published: June 2010

The diameter-modulated single crystalline gallium phosphide (GaP) nanochains were synthesized by a facile method within a confined reaction zone. By varying the Ga concentration in the reaction zone, the size of knots of GaP nanochains can be manipulated. These zinc-blende structured GaP nanochains with ⟨111⟩ axial directions possess strong visible emissions around 700 nm at room temperature, indicating their potential applications in light sources, laser or light emitting display devices.
Insights into the ultraviolet spectrum of liquid water from model calculations
Authors: Cabral do Couto Paulo , Chipman Daniel M.
Published: June 2010

With a view toward a better molecular level understanding of the effects of hydrogen bonding on the ultraviolet absorption spectrum of liquid water, benchmark electronic structure calculations using high level wave function based methods and systematically enlarged basis sets are reported for excitation energies and oscillator strengths of valence excited states in the equilibrium water monomer and dimer and in a selection of liquid-like dimer structures. Analysis of the electron density redistribution associated with the two lowest valence excitations of the water dimer shows that these are usually localized on one or the other monomer, although valence hole delocalization can occur for certain relative orientations of the water molecules. The lowest excited state is mostly associated with the hydrogen bond donor and the significantly higher energy second excited state mostly with the acceptor. The magnitude of the lowest excitation energies is strongly dependent on where the valence hole is created, and only to a lesser degree on the perturbation of the excited electron density distribution by the neighboring water molecule. These results suggest that the lowest excitation energies in clusters and liquid water can be associated with broken acceptor hydrogen bonds, which provide energetically favorable locations for the formation of a valence hole. Higher valence excited states of the dimer typically involve delocalization of the valence hole and/or delocalization of the excited electron and/or charge transfer. Two of the higher valence excited states that involve delocalized valence holes always have particularly large oscillator strengths. Due to the pervasive delocalization and charge transfer, it is suggested that most condensed phase water valence excitations intimately involve more than one water molecule and, as a consequence, will not be adequately described by models based on perturbation of free water monomer states. The benchmark calculations are further used to evaluate a series of representative semilocal, global hybrid, and range separated hybrid functionals used in efficient time-dependent density functional methods. It is shown that such an evaluation is only meaningful when comparison is made at or near the complete basis set limit of the wave function based reference method. A functional is found that quantitatively describes the two lowest excitations of water dimer and also provides a semiquantitative description of the higher energy valence excited states. This functional is recommended for use in further studies on the absorption spectrum of large water clusters and of condensed phase water.
Implementation and characterization of a quartz tuning fork based probe consisted of discrete resonators for dynamic mode atomic force microscopy
Authors: Akiyama Terunobu , de Rooij Nicolaas F. , Staufer Urs , Detterbeck Manfred , Braendlin Dominik , Waldmeier Simon , Scheidiger Martin
Published: June 2010

The quartz tuning fork based probe {e.g., Akiyama et al. [Appl. Surf. Sci. 210, 18 (2003)]}, termed “A-Probe,” is a self-sensing and self-actuating (exciting) probe for dynamic mode atomic force microscope (AFM) operation. It is an oscillatory force sensor consisting of the two discrete resonators. This paper presents the investigations on an improved A-Probe: its batch fabrication and assembly, mounting on an AFM head, electrical setup, characterization, and AFM imaging. The fundamental features of the A-Probe are electrically and optically characterized in “approach-withdraw” experiments. Further investigations include the frequency response of an A-Probe to small mechanical vibrations externally applied to the tip and the effective loading force yielding between the tip and the sample during the periodic contact. Imaging of an electronic chip, a compact disk stamper, carbon nanotubes, and Si beads is demonstrated with this probe at ambient conditions in the so-called frequency modulation mode. A special probe substrate, which can snap on a receptacle fixed on an AFM head, and a special holder including a preamplifier electronic are introduced. We hope that the implementation and characterization of the A-Probe described in this paper will provide hints for new scanning probe techniques.
Efficient evaluation of the Coulomb force in the Gaussian and finite-element Coulomb method
Authors: Kurashige Yuki , Nakajima Takahito , Sato Takeshi , Hirao Kimihiko
Published: June 2010

We propose an efficient method for evaluating the Coulomb force in the Gaussian and finite-element Coulomb (GFC) method, which is a linear-scaling approach for evaluating the Coulomb matrix and energy in large molecular systems. The efficient evaluation of the analytical gradient in the GFC is not straightforward as well as the evaluation of the energy because the SCF procedure with the Coulomb matrix does not give a variational solution for the Coulomb energy. Thus, an efficient approximate method is alternatively proposed, in which the Coulomb potential is expanded in the Gaussian and finite-element auxiliary functions as done in the GFC. To minimize the error in the gradient not just in the energy, the derived functions of the original auxiliary functions of the GFC are used additionally for the evaluation of the Coulomb gradient. In fact, the use of the derived functions significantly improves the accuracy of this approach. Although these additional auxiliary functions enlarge the size of the discretized Poisson equation and thereby increase the computational cost, it maintains the near linear scaling as the GFC and does not affects the overall efficiency of the GFC approach.
On chip, high-sensitivity thermal sensor based on high-Q polydimethylsiloxane-coated microresonator
Authors: Li Bei-Bei , Wang Qing-Yan , Xiao Yun-Feng , Jiang Xue-Feng , Li Yan , Xiao Lixin , Gong Qihuang
Published: June 2010

A high-sensitivity thermal sensing is demonstrated by coating a layer of polydimethylsiloxane (PDMS) on the surface of a silica toroidal microresonator on a silicon wafer. Possessing high-Q whispering gallery modes (WGMs), the PDMS-coated microresonator is highly sensitive to the temperature change in the surroundings. We find that, when the PDMS layer becomes thicker, the WGM experiences a transition from redshift to blueshift with temperature increasing due to the negative thermal-optic coefficient of PDMS. The measured sensitivity (0.151 nm/K) is one order of magnitude higher than pure silica microcavity sensors. The ultrahigh resolution of the thermal sensor is also analyzed to reach 10−4 K.
Electrostatic charge accumulation versus electrochemical doping in SrTiO3 electric double layer transistors
Authors: Ueno K. , Shimotani H. , Iwasa Y. , Kawasaki M.
Published: June 2010

In electric double layer transistors with SrTiO3 single crystals, we found distinct differences between electrostatic charge accumulation and electrochemical reaction depending on bias voltages. In contrast to the reversible electrostatic process below 3.7 V with a maximum sheet charge carrier density, nS, of 1014 cm−2, the electrochemical process causes persistent conduction even after removal of the gate bias above 3.75 V. nS reached 1015 cm−2 at 5 V, and the electron mobility at 2 K was as large as 104 cm2/V s. This persistent conduction originates from defect formation within a few micrometers depth of SrTiO3.
Elimination of threading dislocations in as-grown PbSe film on patterned Si(111) substrate using molecular beam epitaxy
Authors: Weng Binbin , Zhao Fanghai , Ma Jiangang , Yu Guangzhe , Xu Jian , Shi Zhisheng
Published: June 2010

A high-quality as-grown PbSe film with a record low threading dislocation density of 9×105 cm−2 on patterned Si(111) substrate has been obtained using molecular beam epitaxy. The mechanisms leading to the remarkable reduction in threading dislocation density are analyzed. Based on the analysis, further reduction in dislocation density is anticipated. Materials with such low dislocation density should significantly improve the Si-based IV-VI group device performance.
Photoemission from localized surface plasmons in fractal metal nanostructures
Authors: Word R. C. , Dornan T. , Könenkamp R.
Published: June 2010

We use photoemission microscopy to characterize localized surface plasmon distributions in nanostructured gold layers on indium-tin-oxide/glass substrates. The Au films have a fractal dimension of ∼1.3 and smallest feature sizes of ∼100 nm. We use femtosecond laser pulses at a wavelength of ∼800 nm for the plasmon excitation. Photoelectron emission occurs by a three-photon process in localized areas of indium-tin-oxide with ∼70 nm diameter. In these areas the photoemission rate is enhanced several thousand fold compared to nonstructured surface areas. The results show that plasmon enhanced photoemission can be induced in a nonabsorbing material in proximity to a plasmon-active metal nanostructure.
Dielectric properties of fully hydrated nucleotides in the terahertz frequency range
Authors: Glancy P. , Beyermann W. P.
Published: June 2010

We use terahertz time domain spectroscopy (THz-TDS) to determine the complex frequency-dependent dielectric response of all four nucleotides at different dilute concentrations. In addition, the suspension model’s ability to extract the dielectric response of just the nucleotide with the hydration shell εb excluding the dielectric information relating to the bulk will be verified. The suspension model enables us to make the determination that the nucleotides have influences on the water molecules out to the fourth hydration shell. We use a two Debye relaxation fit model for water, all concentrations and all εb values. We observed how the nucleotides affect the relaxation parameters in relation to that of pure bulk water. With this information, we notice a transition between purines and pyrimidines, where one is a hydrogen-bond network structure building type material with a low concentration increment and the other is a structure breaking type material with a low concentration decrement. Due to conductivity measurements, we determine that kinetic depolarization is a negligible affect compared to that of dielectric saturation, which we find to dominate where a decrement is found.
Population and family structure of brown trout, Salmo trutta, in a Mediterranean stream
Authors: Vera Manuel , Sanz Nuria , Hansen Michael M. , Almodóvar Ana , García-Marín José-Luis
Published: June 2010

The physical arrangement of closely related individuals is expected to significantly influence the pattern of population genetic structure. For example, if related individuals are non-randomly distributed and included in samples, this may lead to exaggerated conclusions about genetic differentiation. In the present study, we compared population structure v. family relationships of brown trout (Salmo trutta L.) along a Mediterranean stream (Pyrenees) by using eight microsatellite loci. Results showed low levels of genetic (FST) differentiation between collections in a 6.5-km transect along the stream, and a significant correlation between genetic and geographical distance matrices, indicating a weak population structure associated with spatial distribution. Our data also indicated that geographical proximity of related individuals in the youngest (0+, 1+) cohorts probably was associated with limited dispersal of younger brown trout from spawning redds. Family relationships provided evidence, however, for movement of adult trout over distances of a few kilometres that probably contributed to the low observed differentiation. Dispersal of adult Mediterranean trout contrasts with the clustering of related older trout observed for some north European rivers and could be related to the reduced productivity in southern stream basins.
Change in wild-oyster assemblages of Port Stephens, NSW, Australia, since commencement of non-native Pacific oyster (Crassostrea gigas) aquaculture
Authors: Bishop Melanie J. , Krassoi Fredrick R. , McPherson Ross G. , Brown Kenneth R. , Summerhayes Stephen A. , Wilkie Emma M. , O'Connor Wayne A.
Published: June 2010

Proliferation of species introduced for aquaculture can threaten the ecological and economic integrity of ecosystems. We assessed whether the non-native Pacific oyster, Crassostrea gigas, has proliferated, spread and overgrown native Sydney rock oysters, Saccostrea glomerata, in Port Stephens, New South Wales (NSW), Australia, following the 1991 decision to permit its aquaculture within this estuary. Sampling of seven rocky-shore and four mangrove sites immediately before (1990), immediately after (1991–1992) and nearly two decades after (2008) the commencement of C. gigas aquaculture did not support the hypotheses of C. gigas proliferation, spread or overgrowth of S. glomerata. The non-native oyster, uncommon immediately before the commencement of aquaculture, remained confined to the inner port and its percentage contribution to oyster assemblages generally declined over the two decades. C. gigas populations were dominated by individuals of <40-mm shell height, with established adults being rare. Only at one site was there an increase in C. gigas abundance that was accompanied by S. glomerata decline. The failure of C. gigas in Port Stephens to cause the catastrophic changes in fouling assemblages seen elsewhere in the world is likely to reflect estuarine circulation patterns that restrict larval transport and susceptibility of the oysters to native predators.
Conformational selection in the molten globule state of the nuclear coactivator binding domain of CBP
Authors: Kjaergaard Magnus , Teilum Kaare , Poulsen Flemming M.
Published: June 2010

Native molten globules are the most folded kind of intrinsically disordered proteins. Little is known about the mechanism by which native molten globules bind to their cognate ligands to form fully folded complexes. The nuclear coactivator binding domain (NCBD) of CREB binding protein is particularly interesting in this respect as structural studies of its complexes have shown that NCBD folds into two remarkably different states depending on the ligand being ACTR or IRF-3. The ligand-free state of NCBD was characterized in order to understand the mechanism of folding upon ligand binding. Biophysical studies show that despite the molten globule nature of the domain, it contains a small cooperatively folded core. By NMR spectroscopy, we have demonstrated that the folded core of NCBD has a well ordered conformer with specific side chain packing. This conformer resembles the structure of the NCBD in complex with the protein ligand, ACTR, suggesting that ACTR binds to prefolded NCBD molecules from the ensemble of interconverting structures.
Soviet war memorials and the re-construction of national and local identities in post-communist Poland
Authors: Ochman Ewa
Published: June 2010

This article proposes to look afresh at the legacies of communism in urban spaces in post-1989 Poland. Specifically, it investigates the fate of Red Army monuments and explores how these public spaces have been used in the multifaceted and multileveled process of post-communist identity formation. The article suggests that Red Army monuments constitute sites for the articulation of new narratives about the country's past and future which are no longer grounded in the fundamental division between “us” (the nation) and “them” (the supporters of communism) and which are far from being fixed in the binary opposition of the banished and the embraced past. The reorganization of public memory space does not only involve contesting the Soviet past or affirming independence traditions but is rather the outcome of multilayered processes rooted in particularities of time and space. Moreover, the article argues that the dichotomy “liberator versus occupier,” often employed as a viable analytical tool by scholars investigating the post-communist memorial landscape, impedes our understanding of the role played by Soviet war memorials in the process of re-imagining national and local communities in post-1989 Eastern Europe.
Integration or separation? Nationality groups in the US and the Republican Party's ethnic politics, 1960s-1980s
Authors: Zake Ieva , Gormley Graham
Published: June 2010

Using examples of American Latvians, Estonians and Ukrainians in the states of Minnesota, New Jersey and New York this article explores the ambiguous nature of integration of nationalities groups inside the Republican Party during the 1960s-1980s. Based on the analysis of available archival information, it is shown that the Republican Party intentionally brought in the ethnics during the discussed period and created the Nationalities Sections within specific electoral campaigns, Nationalities Divisions inside the state party organizations and the National Republican Heritage Groups (Nationalities) Council within the Republican National Committee in order to recruit the ethnics and engage in the partisan struggle with the Democrats. Consequently, the nationalities were given a sense of importance, but little real power to actually influence the internal processes inside the party. At the same time, the nationalities eagerly responded to the invitation to join the Republican national and state-level organizations specifically designed for the ethnics. Yet in doing this they perceived themselves primarily as ethnics with a distinct, mainly anti-communist, agenda and only secondarily thought of themselves as Americans dedicated to Republican politics. Consequently, the Republican political strategy of creating Nationalities Sections and Divisions seemed to integrate the ethnics on the surface, while in reality intensifying political separation and even ghettoization of the ethnics in American politics. This research initiates a larger project, which will compare the Republican and Democratic strategies of directly involving ethnic groups and minorities inside the party organizations in the second part of the twentieth century.
Sovereignty, networks, and norms
Authors: Deets Stephen
Published: June 2010

Despite considerable scholarly work on ethnic mobilization, less attention has been paid to explicitly examining how differing notions of the state undergird our analysis and normative approaches. As the title of Ted Gurr's Peoples versus States reminds us, the state is central to these processes. Similarly, there seems to be widespread, yet little discussed, disagreement on the proper role of politics in ethno-politics. In other words, at what point do we shrug our shoulders and say, “minority X lost this political fight and that's the way democratic politics functions”? The three books here focus on vastly different topics (international minority rights norms, Native American struggles, and the Holy Roman Empire's decline), but in reading them together it is striking how their notions of the state and politics lead us to varying conclusions about the possibilities for minorities.
The dilemmas of identity faced by psychodynamic counsellors training in cognitive behavioural therapy
Authors: Owen-Pugh Valerie
Published: June 2010

Aim: A qualitative study was carried out to explore the dilemmas of identity experienced by qualified psychodynamic counsellors studying cognitive behavioural therapy (CBT). Method: Participants were students on a BA ‘top‐up’ programme that included an introductory module in CBT. Thematic analyses were carried out on participants' learning journals, and on the transcripts of focus groups convened a year after module completion. Findings: As they first engaged with the module, participants held highly negative views of CBT. Many were also resistant to engaging with module content. Over time, they were increasingly able to appraise CBT as an effective and ethical modality and find ways of integrating their new learning with their core theory. Conclusions: The study illustrates the ways in which macro‐political interventions, such as the Improving Access to Psychological Therapies initiative, can impact on the student experience. Training strategies are proposed for supporting counsellors' engagement with unfamiliar modalities.
The challenge of becoming an integrative counsellor: The trainee's perspective
Authors: Lowndes Lisa , Hanley Terry
Published: June 2010

Aim: Integrative therapeutic practice is commonplace within the UK. Counsellors and psychotherapists increasingly report working in this way and numerous training courses have developed which advocate such practice. Despite its popularity, researchers have paid little attention to the impact that such training has upon students. This study therefore explores newly qualified counsellors' reflections of undertaking professional training in integrative counselling. Design: Newly qualified counsellors were invited to take part in a focus group to discuss their training experiences. Two groups were held involving a total of seven people. The data generated was analysed using Grounded Theory. Findings: The core‐category ‘The challenge of becoming an integrative counsellor’ was identified. Embedded within this were four sub‐categories: (1) ‘training issues’, (2) ‘applied issues’, (3) ‘the development of an integrative theory and identity’, and (4) ‘the impact of integrative training post qualification’. Key findings include the willingness of trainees to tolerate theoretical ambiguity and the discomfort that surrounded not belonging to a pure paradigm community. Discussion: Recommendations are made that trainers and practice supervisors are mindful of the distinct struggles that integrative trainees encounter. Additionally, in response to the isolation that some trainees report, greater use of peer support networks is encouraged.