bluuebunny/crossref_metadata_2025 huggingface dataset:
Closed Rupture of the Flexor Tendons Caused by Carpal Bone and Joint Disorders
Authors: YAMAZAKI H. , KATO H. , HATA Y. , NAKATSUCHI Y. , TSUCHIKANE A.
Published: August 2007

We analysed 21 patients with closed rupture of the flexor tendons caused by carpal bone and joint disorders. The tendon that ruptured depended on the location of the bone perforation into the carpal tunnel. Radiocarpal arthrography was performed in 13 patients and capsular perforation was demonstrated by contrast medium leakage into the carpal canal in 11 patients. This proved a useful diagnostic test. The flexor tendon(s) were reconstructed with free tendon graft in 17 patients, crossover transfer of flexor tendons from adjacent digits in two and buddying to an adjacent flexor tendon in one patient. Postoperative total active range of motion in the fingers after 13 free tendon graft reconstructions averaged 213° (range 170–265°). The active range of motion of the thumb-interphalangeal joint after free tendon graft reconstruction in three cases improved from 0° to 33° on average (range 10°–40°).
Why was democracy lost in Russia's regions? Lessons from Nizhnii Novgorod
Authors: Sharafutdinova Gulnaz
Published: August 2007

The phenomenon of crony capitalism has been explored primarily with reference to its impact on economic growth. This study investigates the political implications of crony capitalism and, specifically, the interaction between political competition and crony capitalism. Based on a case study of a political trajectory in one of the regions of the Russian Federation, I argue that under crony capitalism political competition can undermine the legitimacy of state authorities and such democratic institution as the electoral mechanism. Played out in public during the electoral campaigns unrestricted political competition uncovers the predatory nature of crony elites engaged in struggle for power and wealth and increases public perceptions of corruption.
May–June precipitation reconstruction of southwestern anatolia, Turkey during the last 900 years from tree rings
Authors: Touchan Ramzi , Akkemik Ünal , Hughes Malcolm K. , Erkan Nesat
Published: August 2007

A May–June precipitation reconstruction (AD 1097–2000) has been developed for southwestern Anatolia in Turkey, the longest reported to date in this region. The reconstruction was derived from a regional Juniperus excelsa chronology that was built from material sampled at four sites in the Antalya and Mersin Districts. The regional tree-ring chronology accounts for 51% of the variance of instrumentally observed May–June precipitation. The years AD 1518 to 1587 are the most humid period in the reconstruction, coinciding with a major shift in European climate. The driest 70-year period in the reconstruction is AD 1195 to 1264. The period AD 1591–1660 represents the third driest and was characterized by instability climatically, politically, and socially in Anatolia.
Bridging the Gap Between Measurement Models and Theories of Human Memory
Authors: Brandt Martin
Published: August 2007

Two types of formal memory models can be distinguished: measurement models and computational models. Measurement models aim at measuring memory processes. In contrast, computational models focus on explaining the structures and processes underlying memory performance. Whereas measurement models involve a statistical framework for testing the model's assumptions, computational models often cannot be applied to empirical data directly. On the other hand, measurement models usually lack psychological theory, whereas computational models are formalized theories allowing for precise predictions. Using the computational model MINERVA2 as an example, it is shown that the gap between both types of formal models can be bridged quite easily by developing closed-form equations for the model's predictions. The resulting multinomial model combines the advantages of measurement models and computational models. The benefits are demonstrated by applying the model to two experiments on the global similarity effect and the list-length effect. The MINERVA 2-inspired multinomial model provides an excellent fit to the data, a coherent explanation of the effects, and statistically sound measures of the processes involved.
The effective antenna noise figure Fa for a vertical loop antenna and its application to extremely low frequency/very low frequency atmospheric noise
Authors: Fraser‐Smith Antony C.
Published: August 2007

Expressions tabulated for the effective antenna noise figure Fa usually assume an electric field antenna, since most measurements of radio noise are made on the electric field of the noise. Furthermore, the International Radio Consultative Committee (CCIR) noise model predictions for Fa are made only for electrically short grounded vertical monopoles over a perfect ground. However, at frequencies lower than those traditionally used for communications, i.e., at extremely low frequencies (ELF; frequencies in the range 3 Hz to 3 kHz) and very low frequencies (VLF; frequencies in the range 3–30 kHz), it is common for magnetic field loop antennas to be used, and the tabulated expressions for Fa do not apply. This communication reports the derivation of an expression for Fa as measured by a small vertical magnetic loop antenna and its subsequent application to ELF/VLF radio noise measurements made at a variety of locations around the world. There is good agreement between the measured Fa values and estimates of maximum and minimum Fa values for the ELF/VLF range published by Spaulding and Hagn in 1978, but an improved fit to the measurements can be obtained by making moderate adjustments to the maximum and minimum values at both the low (10–100 Hz) and high (8–32 kHz) frequency limits.
A science metrics based citation for tagging the biomedical researchers
Authors: Brandao Adeilton
Published: August 2007

With the thousands of scientific papers being produced every month, picking an authors name, associate it to a research field and right evaluate his or her performance is in most of times a cumbersome task. I am proposing here that science indexes as h-index, g-index, total citations and published papers could be added to biomedical bibliographic citation in order to create a unique identifier for a given researcher.
Unification and extension of the similarity scaling criteria and mixing transition for studying astrophysics using high energy density laboratory experiments or numerical simulations
Authors: Zhou Ye
Published: August 2007

The Euler similarity criteria for laboratory experiments and time-dependent mixing transition are important concepts introduced recently for application to prediction and analysis of astrophysical phenomena. However, Euler scaling by itself provides no information on the distinctive spectral range of high Reynolds number turbulent flows found in astrophysics situations. On the other hand, time-dependent mixing transition gives no indication on whether a flow that just passed the mixing transition is sufficient to capture all of the significant dynamics of the complete astrophysical spectral range. In this paper, a new approach, based on additional insight gained from review of Navier-Stokes turbulence theory, is developed. It allows for revelations about the distinctive spectral scale dynamics associated with high Reynolds number astrophysical flows. From this perspective, the energy-containing range of the turbulent flow measured in a laboratory setting must not be unintentionally contaminated in such a way that the interactive influences of this spectral scale range in the corresponding astrophysical situation cannot be faithfully represented. In this paper, the concept of a minimum state is introduced as the lowest Reynolds number turbulent flow that a time-dependent mixing transition must achieve to fulfill this objective. Later in the paper, the Reynolds number of the minimum state is determined as 1.6×105. The temporal criterion for the minimum state is also obtained. The efforts here can be viewed as a unification and extension of the concepts of both similarity scaling and transient mixing transition concepts. Finally, the implications of our approach in planning future intensive laser experiments or massively parallel numerical simulations are discussed. A systematic procedure is outlined so that as the capabilities of the laser interaction experiments and supporting results from detailed numerical simulations performed in recently advanced supercomputing facilities increase progressively, a strategy is developed so that a progressively increasing range of dynamic structures and their statistical influences on evolving astrophysical flows can be attained in laboratory investigations.
Static and dynamic second hyperpolarizability calculated by time-dependent density functional cubic response theory with local contribution and natural bond orbital analysis
Authors: Ye Aijun , Patchkovskii Serguei , Autschbach Jochen
Published: August 2007

The static and dynamic second hyperpolarizability γ has been investigated by time-dependent density functional cubic response theory. The third-order coupled perturbed Kohn-Sham equations were solved to obtain the third-order perturbed charge density. Calculations on a number of small molecules (N2, CO2, C2H4, CO, HF, H2O, and CH4), paradisubstituted oligoacetylene chains, benzene, and eight paradisubstituted benzenes were performed to verify the implementation and to assess the accuracy of the nonhybrid and hybrid time-dependent density functional theory computations. Nitroaniline and a derivative were taken as examples to investigate the distribution of the “γ density” and to demonstrate the feasibility of analyzing cubic response functions in terms of contributions from natural bond orbitals (NBOs) and natural localized molecular orbitals (NLMOs). The results highlight the contributions from atoms and bonds on different functional groups to the total value of γ based on the NBO/NLMO analysis, which might be helpful for new nonlinear optical materials design.
Experimental investigation of steady buoyant-thermocapillary convection near an evaporating meniscus
Authors: Dhavaleswarapu Hemanth K. , Chamarthy Pramod , Garimella Suresh V. , Murthy Jayathi Y.
Published: August 2007

Micro-particle image velocimetry measurements of the three-dimensional (3D) convection patterns generated near an evaporating meniscus in horizontally oriented capillary tubes are presented. Analysis of the vapor diffusion away from the meniscus reveals a zone of intense heat flux near the solid-liquid-vapor junction that creates a temperature gradient along the meniscus. This results in a surface tension gradient which, coupled with buoyancy effects, causes buoyant-thermocapillary convection in the liquid film. The relative influence of buoyancy and thermocapillarity on the flow was investigated for tube diameters ranging from 75 to 1575μm. A transition from a pure two-dimensional thermocapillary flow to a 3D buoyant-thermocapillary flow is observed with an increase in tube diameter. For the 75μm tube, a symmetrical toroidal vortex is observed near the meniscus. For larger tubes, buoyancy effects become apparent as they dominate the flow field. The high mass fluxes in smaller-diameter tubes drive stronger vortices. Particle streaks and micro-particle image velocimetry images obtained in multiple horizontal and vertical planes provide an understanding of this three-dimensional flow behavior. A scaling analysis shows the importance of thermocapillary convection in evaporating menisci.
Effects of low and high mode number tearing modes in divertor tokamaks
Authors: Punjabi Alkesh , Ali Halima , Boozer Allen , Evans Todd
Published: August 2007

The topological effects of magnetic perturbations on a divertor tokamak, such as DIII-D, are studied using field-line maps that were developed by Punjabi et al. [A. Punjabi, A. Verma, and A. Boozer, Phys. Rev. Lett. 69, 3322 (1992)]. The studies consider both long-wavelength perturbations, such as those of m=1, n=1 tearing modes, and localized perturbations, which are represented as a magnetic dipole. The parameters of the dipole map are set using DIII-D data from shot 115467 in which the C-coils were activated [J. L. Luxon and L. E. Davis, Fusion Technol. 8, 441 (1985)]. The long-wavelength perturbations alter the structure of the interception of magnetic field lines with the divertor plates, but the interception is in sharp lines. The dipole perturbations cause a spreading of the interception of the field lines with the divertor plates, which alleviates problems associated with heat deposition. Magnetic field lines are the trajectories of a one-and-a-half degree of freedom Hamiltonian, which strongly constrains the topological features of the lines. Although the field line maps that we use do not accurately represent the trajectories through ordinary space of individual field lines, they do represent their topological structure.
Dynamic analysis of the fractional-order Liu system and its synchronization
Authors: Wang Xing-yuan , Wang Ming-jun
Published: August 2007

Based on the stability theory of fractional-order systems, the dynamic behaviors of fractional-order Liu system are studied theoretically. Coupling synchronization of two identical fractional-order chaotic systems is also studied and a simple criterion is presented. Numerical simulations show the effectiveness of our methods.
The experimental localization of Aubry–Mather sets using regularization techniques inspired by viscosity theory
Authors: Guzzo Massimiliano , Bernardi Olga , Cardin Franco
Published: August 2007

We provide a new method for the localization of Aubry-Mather sets in quasi-integrable two-dimensional twist maps. Inspired by viscosity theories, we introduce regularization techniques based on the new concept of “relative viscosity and friction,” which allows one to obtain regularized parametrizations of invariant sets with irrational rotation number. Such regularized parametrizations allow one to compute a curve in the phase-space that passes near the Aubry-Mather set, and an invariant measure whose density allows one to locate the gaps on the curve. We show applications to the “golden” cantorus of the standard map as well as to a more general case.
Toward effective and reliable fluorescence energies in solution by a new state specific polarizable continuum model time dependent density functional theory approach
Authors: Improta Roberto , Scalmani Giovanni , Frisch Michael J. , Barone Vincenzo
Published: August 2007

A state specific (SS) model for the inclusion of solvent effects in time dependent density functional theory (TD-DFT) computations of emission energies has been developed and coded in the framework of the so called polarizable continuum model (PCM). The new model allows for a rigorous and effective treatment of dynamical solvent effects in the computation of fluorescence and phosphorescence spectra in solution, and it can be used for studying different relaxation time regimes. SS and conventional linear response (LR) models have been compared by computing the emission energies for different benchmark systems (formaldehyde in water and three coumarin derivatives in ethanol). Special attention is given to the influence of dynamical solvation effects on LR geometry optimizations in solution. The results on formaldehyde point out the complementarity of LR and SS approaches and the advantages of the latter model especially for polar solvents and/or weak transitions. The computed emission energies for coumarin derivatives are very close to their experimental counterparts, pointing out the importance of a proper treatment of nonequilibrium solvent effects on both the excited and the ground state energies. The availability of SS-PCM/TD-DFT models for the study of absorption and emission processes allows for a consistent treatment of a number of different spectroscopic properties in solution.
Novel apparatus to measure hyperthermal heavy ion damage to DNA: Strand breaks, base loss, and fragmentation
Authors: Sellami L. , Lacombe S. , Hunting D. , Wagner R. J. , Huels M. A.
Published: August 2007

We have developed a novel apparatus that allows us to irradiate nonvolatile organic films of high mass (1–100μg range) spread out over a large surface area (42cm2) with low energy (kT–100eV) heavy ions and to quantitatively analyze the film substance via standard biochemical techniques afterwards. Here we discuss the details of the apparatus and method and show that it allows us to measure substantial damage to double stranded DNA molecules (plasmids) and its fundamental subunits induced by heavy ions with unprecedented low energies, i.e., 2.5eV∕amu; these energies correspond to track end energies of stopping ions or secondary ions created along primary ion tracks. We find that hyperthermal Ar+ ions interacting with plasmid DNA will lead to the formation of single and double strand breaks, as well as fragmentation of nucleosides, which also involve chemical modifications and site specific rupture along the N1–C1 glycosidic bond, resulting in base release. In cells, such localized clustered damage will enhance the severity of DNA strand lesions, thus making them harder to repair.
Dependence of the energies of fusion on the intermembrane separation: Optimal and constrained
Authors: Lee J. Y. , Schick M.
Published: August 2007

We calculate the characteristic energies of fusion between planar bilayers as a function of the distance between them, measured from the hydrophobic/hydrophilic interface of one of the two nearest, cis, leaves to the other. The two leaves of each bilayer are of equal composition: 0.6 volume fraction of a lamellar-forming amphiphile, such as dioleoylphosphatidylcholine, and 0.4 volume fraction of a hexagonal-forming amphiphile, such as dioleoylphosphatidylethanolamine. Self-consistent field theory is employed to solve the model. We find that the largest barrier to fusion is that to create the metastable stalk. This barrier is the smallest, about 14.6kBT, when the bilayers are at a distance about 20% greater than the thickness of a single leaf, a distance which would correspond to between 2 and 3nm for typical bilayers. The very size of the protein machinery which brings the membranes together can prevent them from reaching this optimum separation. For even modestly larger separations, we find a linear rate of increase of the free energy with distance between bilayers for the metastable stalk itself and for the barrier to the creation of this stalk. We estimate these rates for biological membranes to be about 7.1kBT∕nm and 16.7kBT∕nm, respectively. The major contribution to this rate comes from the increased packing energy associated with the hydrophobic tails. From this we estimate, for the case of hemagglutinin, a free energy of 38kBT for the metastable stalk itself and a barrier to create it of 73kBT. Such a large barrier would require that more than a single hemagglutinin molecule be involved in the fusion process, as is observed.
In situ mechanical characterization of polymers with the association of three optical techniques
Authors: André Stéphane , Baravian Christophe , Renault Norbert , Cunat Christian
Published: August 2007

A combination of three optical techniques is presented for in situ monitoring of macroscopic and microscopic variables characterizing the deformation of polymers. A video extensometer allows for the monitoring of true stress and strain. An infrared imager along with an appropriate mathematical algorithm allows for the determination of the energies that are converted into heat during the whole test. This makes possible a quantification of thermomechanical couplings revealing structural effects at microscopic scales. Finally, incoherent steady light transport is used to produce images of backscattered intensities. A physical model enables the authors to follow damaging processes occurring at microscopic scales.
Synthesis and analysis of abnormal wurtzite ZnSe nanowheels
Authors: Jin Lei , Choy Wallace C. H. , Leung Yee P. , Yuk Tong I. , Ong Hock C. , Wang Jian-bo
Published: August 2007

An abnormal structure of the ZnSe nanowheels composed of teethlike extended patterns on nanoring bases has been successfully synthesized by thermal evaporation method. It is interesting to note that the as-synthesized ZnSe nanowheels are metastable wurtzite phase with the dominant exposed surfaces of ±(21¯1¯0) while the stable ZnSe is typically zinc blende phase. A full picture of the growth mechanism of the metastable wurtzite phase ZnSe nanostructures will be proposed from the thermodynamic point of view. Meanwhile, the formation of the nanowheels is also explained by a two-stage mechanism. In the first stage, the base of the nanowheel begins to form by vapor-solid mechanism, while in the second stage, the teethlike extended structures grow through the self-catalyzed growth process. The cathodoluminescence spectrum of ZnSe nanowheel exhibited a band edge transition at about 460nm and a strong self-activated luminescence at 610nm. It is important to note that the discussions of the nanostructure thermodynamics and stability can be applied to understand the growth mechanism of other nanostructures which are critical for optimization of the nanostructures.
Nonlinear kinetic model for lower-hybrid solitary structures
Authors: Jovanović D. , Shukla P. K. , Morfill G.
Published: August 2007

Nonlinear drift-kinetic theory is proposed for lower-hybrid solitary structures in near-Earth plasmas, based on a two time scale kinetic description of nonlinear interactions between the lower-hybrid and dispersive Alfvén waves. The detailed derivation of the nonlinear coupling terms in an arbitrary geometry is presented, that include the ponderomotive potential, non-curl-free component of the perpendicular electron velocity, and the electron diffusion in velocity space. It is shown that the resonant particles are trapped by the combined effects of the slow and ponderomotive potentials, and that their density is further modified by their diffusion in velocity space, yielding a new type of coherent structure, which is identified as an electron hole, coupled with a nonlinear Schrödinger-type soliton. A numerical solution is found in the form of train of soliton-like lower-hybrid spikes, trapped inside a weakly two-dimensional slab electron hole.
Nitrogen passivation of (0001) 4H-SiC silicon-face dangling bonds
Authors: Pennington G. , Ashman C. R.
Published: August 2007

The authors report a density functional theory study of nitrogen passivation of the (0001) Si face of 4H-SiC. Results indicate that (1) upon passivation dangling bond density is reduced near the conduction band and increased near the valence band and (2) stable nitrogen coverage is allowed only up to 1∕3 of a monolayer. Although an oxygen environment is not considered, these findings concur with experimental studies of 4H-SiC metal-oxide-semiconductor field-effect transistors which have undergone gate oxide annealing in the presence of nitrogen. Simulations indicate that nitrogen may reduce interface state density by removing 4H-SiC Si-face dangling bonds.
Efficient terahertz room-temperature photonic crystal nanocavity laser
Authors: Englund Dirk , Altug Hatice , Fushman Ilya , Vučković Jelena
Published: August 2007

The authors describe an efficient surface-passivated photonic crystal nanocavity laser, demonstrating room-temperature operation with 3ps pulse duration (detector response limited) and low-temperature operation with an ultralow threshold of 9μW.
Organic solar cells on indium tin oxide and aluminum doped zinc oxide anodes
Authors: Schulze Kerstin , Maennig Bert , Leo Karl , Tomita Yuto , May Christian , Hüpkes Jürgen , Brier Eduard , Reinold Egon , Bäuerle Peter
Published: August 2007

The authors compare organic solar cells using two different transparent conductive oxides as anode: indium tin oxide (ITO) and three kinds of aluminum doped zinc oxide (ZAO). These anodes with different work functions are used for small molecule photovoltaic devices based on an oligothiophene derivative as donor and fullerene C60 as acceptor molecule. It turns out that cells on ITO and ZAO have virtually identical properties. In particular, the authors demonstrate that the work function of the anode does not influence the Voc of the photovoltaic device due to the use of doped transport layers.
Coupling between surface plasmons and nonresonant transmission in subwavelength holes at terahertz frequencies
Authors: Han Jiaguang , Azad Abul K. , Gong Mufei , Lu Xinchao , Zhang Weili
Published: August 2007

Transmission spectra of terahertz pulses through periodic array of subwavelength holes exhibit a characteristic evolution with various hole widths. The peak absolute transmittance approaches a maximum value at a critical hole width, while linewidth broadening and blueshift of peak frequency are observed with increasing hole width. Such characteristic evolution is attributed to the coupling between discrete resonant excitation of surface plasmons and continuum nonresonant transmission through the holes; this agrees well with the numerical analysis based on the Fano model and the measured angle-resolved transmission band structures.
Finite temperature corrections and embedded strings in noncommutative geometry and the standard model with neutrino mixing
Authors: Martins R. A.
Published: August 2007

The recent extension of the standard model to include massive neutrinos in the framework of noncommutative geometry and the spectral action principle involves new scalar fields and their interactions with the usual complex scalar doublet. After ensuring that they bring no unphysical consequences, we address the question of how these fields affect the physics predicted in the Weinberg-Salam theory, particularly in the context of the electroweak phase transition. Applying the Dolan-Jackiw procedure, we calculate the finite temperature corrections, and find that the phase transition is first order. The new scalar interactions significantly improve the stability of the electroweak Z string, through the “bag” phenomenon described by Vachaspati and Watkins [“Bound states can stabilize electroweak strings,” Phys. Lett. B 318, 163–168 (1993)]. (Recently, cosmic strings have climbed back into interest due to a new evidence.) Sourced by static embedded strings, an internal space analogy of Cartan’s torsion is drawn, and a possible Higgs-force-like “gravitational” effect of this nonpropagating torsion on the fermion masses is described. We also check that the field generating the Majorana mass for the νR is nonzero in the physical vacuum.
Current transport mechanism of Au∕Ni∕GaN Schottky diodes at high temperatures
Authors: Huang S. , Shen B. , Wang M. J. , Xu F. J. , Wang Y. , Yang H. Y. , Lin F. , Lu L. , Chen Z. P. , Qin Z. X. , Yang Z. J. , Zhang G. Y.
Published: August 2007

Current transport mechanism in Au∕Ni∕GaN Schottky diodes has been investigated using current-voltage characterization technique between 27 and 350°C. It is found that the ideality factor n of the diode decreases with increasing temperature when the temperature is lower than 230°C, and then increases with increasing temperature when the temperature is higher than 230°C. The corresponding Schottky barrier height (SBH) increases all through the temperature range. Thermionic-emission model with a Gaussian distribution of SBHs is thought to be responsible for the electrical behavior at temperatures lower than 230°C, while the generation-recombination (GR) process takes place in at temperatures above 230°C. The effective Richardson constant is determined to be 24.08Acm−2K−2, in excellent agreement with the theoretical value. The extrapolated activation energy of the GR process is determined to be 1.157eV. Based on the cathodoluminescence measurements, it is suggested that the deep level defects inducing yellow luminescence facilitate the GR process of the current transport in the diodes.
Study on the synthesis of high quality single crystalline Si1−xGex nanowire and its transport properties
Authors: Whang S. J. , Lee S. J. , Yang W. F. , Cho B. J. , Kwong D. L.
Published: August 2007

In this wok, the authors report a synthesis of high quality single crystalline homogeneous Si1−xGex nanowires and investigate the effects of growth temperature on the microstructures, morphologies, and properties of Si1−xGex nanowires. Fabricated phosphorus-doped Si1−xGex nanowire metal-oxide-semiconductor (MOS) field effect transistor integrated with 5nm HfO2, TaN∕Ta metal gate, and Pd source/drain electrode demonstrated enhancement mode p-MOS operation with Ion∕Ioff∼104, subthreshold swing of ∼136mV/decade, and small hysteresis of 90mV.
Temperature-dependent leakage mechanisms of Pt∕BiFeO3∕SrRuO3 thin film capacitors
Authors: Yang H. , Jain M. , Suvorova N. A. , Zhou H. , Luo H. M. , Feldmann D. M. , Dowden P. C. , DePaula R. F. , Foltyn S. R. , Jia Q. X.
Published: August 2007

Epitaxial c-axis oriented BiFeO3 (BFO) thin films were deposited on conductive SrRuO3 (SRO) on (001) SrTiO3 substrates by pulsed laser deposition. A Pt/BFO/SRO capacitor was constructed by depositing a top Pt electrode. The leakage current density versus. electric field characteristics were investigated from 80to350K. It was found that the leakage mechanisms were a strong function of temperature and voltage polarity. At temperatures between 80 and 150K, space-charge-limited current was the dominant leakage mechanism for both negative and positive biases. On the other hand, at temperatures between 200 and 350K the dominant leakage mechanisms were Poole-Frenkle emission and Fowler-Nordheim tunneling for negative and positive biases, respectively.
Continuous-wave stimulated emission and optical amplification in europium (III)-aluminum nanocluster-doped polymeric waveguide
Authors: Yamashita K. , Taniguchi H. , Yuyama S. , Oe K. , Sun J. , Mataki H.
Published: August 2007

The authors have demonstrated stimulated emission from polymer-based planar waveguide doped with Eu–Al nanoclusters under continuous-wave optical pumping. For the waveguide sample with a nanocluster concentration of 5.0wt%, amplified spontaneous emission was observed in the spectra of the light decoupled from the waveguide edge under a pumping density of 0.16–1.55W∕cm2. The optical gain coefficient was 0.92mm−1 when pumped at 1.55W∕cm2. The well-suppressed concentration quenching and multiphonon quenching may cause the high-gain and low-threshold optical amplification. These results show that the Eu–Al nanocluster is a promising material for polymer-based solid-state lasers and waveguide-type optical amplifiers.
Generation of nanoparticle colloids by picosecond and femtosecond laser ablations in liquid flow
Authors: Barcikowski Stephan , Menéndez-Manjón Ana , Chichkov Boris , Brikas Marijus , Račiukaitis Gediminas
Published: August 2007

Fabrication of silver nanoparticle colloids using ultrashort pulse laser ablation in water is studied. Ablation in liquid flow improves the reproducibility and increases the nanoparticle productivity by 380% compared to stationary liquid. Femtosecond laser ablation in water is 20% more efficient than picosecond laser ablation, but due to higher picosecond laser power (higher repetition rate), the nanoparticle productivity at the same pulse fluence is three times higher for picosecond laser ablation. With picosecond laser pulses, the maximum productivity of 8.6μg∕s is achieved at a pulse energy of 110μJ and repetition rate of 50kHz.
Thermally mediated droplet formation in microchannels
Authors: Nguyen Nam-Trung , Ting Teck-Hui , Yap Yit-Fatt , Wong Teck-Neng , Chai John Chee-Kiong , Ong Wee-Liat , Zhou Junlong , Tan Say-Hwa , Yobas Levent
Published: August 2007

Precise dispensing of microdroplets is an important process for droplet-based microfluidics. The droplet formation by shear force between two immiscible fluids depends on their flow rates, the viscosities, and the interfacial tension. In this letter, the authors report the use of integrated microheater and temperature sensor for controlling the droplet formation process. The technique exploits the dependency on temperature of viscosities and interfacial tension. Using a relatively low heating temperature ranging from 25to70°C, the droplet diameter can be adjusted to over two times of its original value. The relatively low temperature range makes sure that this concept is applicable for droplets containing biological samples.
Serendipitous backyard hybridization and the origin of crops
Authors: Hughes Colin E. , Govindarajulu Rajanikanth , Robertson Ashley , Filer Denis L. , Harris Stephen A. , Bailey C. Donovan
Published: August 2007

Backyard gardens, dump heaps, and kitchen middens are thought to have provided important venues for early crop domestication via generation of hybrids between otherwise isolated plant species. However, this process has rarely been demonstrated empirically. For the majority of polyploid crops, it remains uncertain to what extent hybridization and polyploidization preceded domestication or were precipitated by human activities. Using archaeological, ethnobotanical, geographical, and genetic data, we investigate the extent and significance of predomestication cultivation, backyard sympatry, and spontaneous hybridization for the Mimosoid legume tree
Leucaena
, which is used as a food crop throughout south-central Mexico. We show that predomestication cultivation was widespread, involved numerous independent transitions from the wild to cultivation, and resulted in extensive artificial sympatry of 2–6 species locally and 13 species in total. Using chloroplast and rapidly evolving nuclear-encoded DNA sequences, we demonstrate that hybridization in
Leucaena
has been extensive and complex, spawning a diverse set of novel hybrids as a result of juxtaposition of species in cultivation. The scale and complexity of hybridization in
Leucaena
is significantly greater than that documented for any other Mexican plant domesticates so far. However, there are striking parallels between
Leucaena
and the other major Mexican perennial domesticates
Agave
and
Opuntia
, which show very similar domestication via backyard hybridization pathways. Our results suggest that backyard hybridization has played a central role in Mesoamerican crop domestication and demonstrate that the simple step of bringing species together in cultivation can provide a potent trigger for domestication.
Heteroresistance to penicillin in
Streptococcus pneumoniae
Authors: Morand Brigitte , Mühlemann Kathrin
Published: August 2007

Heteroresistance to β-lactam antibiotics has been mainly described for staphylococci, for which it complicates diagnostic procedures and therapeutic success. This study investigated whether heteroresistance to penicillin exists in
Streptococcus pneumoniae
. Population analysis profile (PAP) showed the presence of subpopulations with higher penicillin resistance in four of nine clinical pneumococcal strains obtained from a local surveillance program (representing the multiresistant clones ST179, ST276, and ST344) and in seven of 16 reference strains (representing the international clones Spain
23F
-1, Spain
9V
-3, Spain
14
-5, Hungary
19A
-6, South Africa
19A
-13, Taiwan
23F
-15, and Finland
6B
-12). Heteroresistant strains had penicillin minimal inhibitory concentrations (MICs) (for the majority of cells) in the intermediate- to high-level range (0.19–2.0 μg/ml). PAP curves suggested the presence of subpopulations also for the highly penicillin-resistant strains Taiwan
19F
-14, Poland
23F
-16, CSR
19A
-11, and CSR
14
-10. PAP of bacterial subpopulations with higher penicillin resistance showed a shift toward higher penicillin-resistance levels, which reverted upon multiple passages on antibiotic-free media. Convergence to a homotypic resistance phenotype did not occur. Comparison of two strains of clone ST179 showed a correlation between the heteroresistant phenotype and a higher-penicillin MIC and a greater number of altered penicillin-binding proteins (PBP1a, -2b, and -2x), respectively. Therefore, heteroresistance to penicillin occurs in international multiresistant clones of
S. pneumoniae
. Pneumococci may use heteroresistance to penicillin as a tool during their evolution to high penicillin resistance, because it gives the bacteria an opportunity to explore growth in the presence of antibiotics before acquisition of resistance genes.
Stability and control of resistive wall modes in high beta, low rotation DIII-D plasmas
Authors: Garofalo A.M. , Jackson G.L. , La Haye R.J. , Okabayashi M. , Reimerdes H. , Strait E.J. , Ferron J.R. , Groebner R.J. , In Y. , Lanctot M.J. , Matsunaga G. , Navratil G.A. , Solomon W.M. , Takahashi H. , Takechi M. , Turnbull A.D.
Published: August 2007

Recent high-β DIII-D (Luxon J.L.2002Nucl. Fusion4264) experiments with the new capability of balanced neutral beam injection show that the resistive wall mode (RWM) remains stable when the plasma rotation is lowered to a fraction of a per cent of the Alfvén frequency by reducing the injection of angular momentum in discharges with minimized magnetic field errors. Previous DIII-D experiments yielded a high plasma rotation threshold (of order a few per cent of the Alfvén frequency) for RWM stabilization when resonant magnetic braking was applied to lower the plasma rotation. We propose that the previously observed rotation threshold can be explained as the entrance into a forbidden band of rotation that results from torque balance including the resonant field amplification by the stable RWM. Resonant braking can also occur naturally in a plasma subject to magnetic instabilities with a zero frequency component, such as edge localized modes. In DIII-D, robust RWM stabilization can be achieved using simultaneous feedback control of the two sets of non-axisymmetric coils. Slow feedback control of the external coils is used for dynamic error field correction; fast feedback control of the internal non-axisymmetric coils provides RWM stabilization during transient periods of low rotation. This method of active control of then= 1 RWM has opened access to new regimes of high performance in DIII-D. Very high plasma pressure combined with elevatedqminfor high bootstrap current fraction, and internal transport barriers for high energy confinement, are sustained for almost 2 s, or 10 energy confinement times, suggesting a possible path to high fusion performance, steady-state tokamak scenarios.
Non-linear dynamics of Alfvén eigenmodes excited by thermonuclear alpha particles in the presence of ion cyclotron resonance heating
Authors: Bergkvist T. , Hellsten T. , Holmström K.
Published: August 2007

Alfvén eigenmodes (AEs) excited by thermonuclear α-particles can degrade the heating efficiency by spatial redistribution of the resonant α-particles. Changes of the orbit invariants in phase space by collisions and interactions with other waves, such as magnetosonic waves during ion cyclotron resonance heating (ICRH), lead to changes in the phase between the α-particles and AEs, causing a decorrelation of the interactions and stronger redistribution of the α-particles. Cyclotron interactions increase the decorrelation of the AE interactions with the high-energy ions and hence a stronger radial redistribution of the high-energy α-particles by the AEs. Renewal of the distribution function by thermonuclear reactions and losses of α-particles to the wall lead to a continuous drive of the AEs and a radial redistribution of the α-particles. The condition for excitation of AEs is shown to depend on the heating scenario where heating at the low field side creates a significant population of high-energy non-standard orbits which drive the modes. The redistribution results in a reduction in the averaged α-particle energy and a degradation of the heating efficiency. The effect on the distribution function in the presence of several unstable modes is not additive and the particle redistribution is found to saturate with an increasing number of modes.
Pioneering Modern Corporate Governance: A View from London in 1900
Authors: Hannah Leslie
Published: August 2007

Around 1900 Britain was exceptionally suited to pioneering large scale enterprises because of the precocious development of its equity markets and London's experimentation with a more eclectic range of corporate governance techniques than the world's smaller and less cosmopolitan financial centers. Information dissemination, incentives, and reputation—developed by a serendipitous mix of legal compulsions and flexible voluntarism—set the scene for the growth of large, UK-based, national and international corporations in the twentieth century.

“The investment business is not with us as well developed or as well understood as it is in England.”

W. H. Lyon, Capitalization (Boston, 1913), 207.
Anglerfish catchability for swept-area abundance estimates in a new survey trawl
Authors: Reid D. G. , Allen V. J. , Bova D. J. , Jones E. G. , Kynoch R. J. , Peach K. J. , Fernandes P. G. , Turrell W. R.
Published: August 2007

Reid, D. G., Allen, V. J., Bova, D. J., Jones, E. G., Kynoch, R. J., Peach, K. J., Fernandes, P. G., and Turrell, W. R. 2007. Anglerfish catchability for swept-area abundance estimates in a new survey trawl. – ICES Journal of Marine Science, 64: 1503–1511. In 2005, a new trawl survey was launched in Scotland to estimate anglerfish (Lophius spp.) abundance using swept-area estimates. This required an understanding of the herding of the fish by the gear, particularly in the zone between the doors and wing ends. TV observations at the wing ends and along the sweeps were used to quantify the behavioural reactions of anglerfish. These observations were analysed to develop a gear efficiency estimate. This paper details the construction of the net and the procedures for data collection on the survey. In all, 54 reliable observations of anglerfish were recorded at the groundgear, the wing ends, and along the sweep/bridle combination. Detailed analysis of the recordings showed that all fish in the path of the net were captured, whereas more than half of the fish between the wings and the doors were not. The fish did not appear to herd and many of the encounters with the wires were passive. An individual-based particle-tracking model was constructed to use the behavioural observations to simulate the capture process and generate an efficiency factor. The calculated efficiency factor, based on the behavioural observations, was 1.04, indicating that almost all fish encountering the sweeps and bridles were lost. The implications and suggestions for development of this work are discussed.
Lemierre Syndrome: Two Cases and a Review
Authors: Syed Mohammed Iqbal , Baring David , Addidle Michael , Murray Craig , Adams Calum
Published: August 2007

Objectives: Lemierre syndrome is usually caused by an acute oropharyngeal infection in previously healthy young adults, resulting in thrombophlebitis of the internal jugular vein, leading to metastatic septic embolization and bacteraemia. The usual organism is Fusobacterium necrophorum. Lemierre syndrome, not so long ago labeled as the “forgotten disease,” is on the rise. Today with increasing antibiotic‐resistant organisms, and decreasing awareness of the syndrome, subsequent re‐emergence of this “forgotten disease” is becoming more common in clinical settings. Lemierre syndrome has significant morbidity. Cranial nerve complications associated with the condition have been increasingly diagnosed in the last few years. Looking back at literature on Lemierre syndrome, there have been review articles in medical and microbiology journals but rarely in otolaryngology journals. By presenting our cases we demonstrate the diverse presentations and severity of the illness.

Methods: A review of the literature and a case report on two cases seen in our institution in the last year are presented. Each of these had varied presentations and neurologic complications—one developed 9th to 12th cranial nerve palsies and Horner syndrome, which have not been described in previous literature, and the other developed polyneuropathy and a frontal lobe infarct among other multisystem complications.

Conclusions: Diagnosis of Lemierre syndrome is not always straightforward as clinical features are variable and blood cultures are often negative. Awareness of the syndrome and a high degree of suspicion are needed.
Switching of the core transcription machinery during myogenesis
Authors: Deato Maria Divina E. , Tjian Robert
Published: August 2007

Transcriptional mechanisms that govern cellular differentiation typically include sequence-specific DNA-binding proteins and chromatin-modifying activities. These regulatory factors are assumed necessary and sufficient to drive both divergent programs of proliferation and terminal differentiation. By contrast, potential contributions of the basal transcriptional apparatus to orchestrate cell-specific gene expression have been poorly explored. In order to probe alternative mechanisms that control differentiation, we have assessed the fate of the core promoter recognition complex, TFIID, during skeletal myogenesis. Here we report that differentiation of myoblast to myotubes involves the disruption of the canonical holo-TFIID and replacement by a novel TRF3/TAF3 (TBP-related factor 3/TATA-binding protein-associated factor 3) complex. This required switching of core promoter complexes provides organisms a simple yet effective means to selectively turn on one transcriptional program while silencing many others. Although this drastic but parsimonious transcriptional switch had previously escaped our attention, it may represent a more general mechanism for regulating cell type-specific terminal differentiation.
Dual Regulation Role of GH3.5 in Salicylic Acid and Auxin Signaling during Arabidopsis-Pseudomonas syringae Interaction
Authors: Zhang Zhongqin , Li Qun , Li Zhimiao , Staswick Paul E. , Wang Muyang , Zhu Ying , He Zuhua
Published: August 2007

Salicylic acid (SA) plays a central role in plant disease resistance, and emerging evidence indicates that auxin, an essential plant hormone in regulating plant growth and development, is involved in plant disease susceptibility. GH3.5, a member of the GH3 family of early auxin-responsive genes in Arabidopsis (Arabidopsis thaliana), encodes a protein possessing in vitro adenylation activity on both indole-3-acetic acid (IAA) and SA. Here, we show that GH3.5 acts as a bifunctional modulator in both SA and auxin signaling during pathogen infection. Overexpression of the GH3.5 gene in an activation-tagged mutant gh3.5-1D led to elevated accumulation of SA and increased expression of PR-1 in local and systemic tissues in response to avirulent pathogens. In contrast, two T-DNA insertional mutations of GH3.5 partially compromised the systemic acquired resistance associated with diminished PR-1 expression in systemic tissues. The gh3.5-1D mutant also accumulated high levels of free IAA after pathogen infection and impaired different resistance-gene-mediated resistance, which was also observed in the GH3.6 activation-tagged mutant dfl1-D that impacted the auxin pathway, indicating an important role of GH3.5/GH3.6 in disease susceptibility. Furthermore, microarray analysis showed that the SA and auxin pathways were simultaneously augmented in gh3.5-1D after infection with an avirulent pathogen. The SA pathway was amplified by GH3.5 through inducing SA-responsive genes and basal defense components, whereas the auxin pathway was derepressed through up-regulating IAA biosynthesis and down-regulating auxin repressor genes. Taken together, our data reveal novel regulatory functions of GH3.5 in the plant-pathogen interaction.