bluuebunny/crossref_metadata_2025 huggingface dataset:
Bayesian experimental design of tracer studies to monitor wastewater leakage from sewer networks
Authors: Rieckermann J. , Borsuk M. E. , Sydler D. , Gujer W. , Reichert P.
Published: August 2010

Despite more than a decade of research, the magnitude of wastewater leakage from defective sewer systems into groundwater supplies is still largely unknown, partly because reliable measurement methods are lacking. Although recently suggested in‐sewer tracer studies present a promising solution, it is unclear how to optimally design such studies in network settings. In this study we present a formal experimental design procedure, which uses Bayesian data analysis to improve the diagnosis of sewer leakage by combining tracer test data with prior knowledge on network topology and condition. From a simulation study, we show that (1) if a single sewer section is expected to have high leakage, that section should be distinguished in measurement layouts through isolated tests or appropriate overlapping of multiple tests; (2) if multiple sections are expected to have high leakage, layouts with tests that cover more than one high‐leakage section should be avoided; and (3) if a robust experimental design is desired, a balanced layout of tests that overlap multiple sections of high leakage, yet minimizes stretch length, should be chosen. This design will have the additional benefit of inducing covariance in the posterior distribution of exfiltration estimates, which can be used to advantage in subsequent studies. We apply these guidelines to a case study of a catchment in Zurich, Switzerland, and find that optimal layout design can improve the anticipated gain of information substantially relative to designs based on practical considerations alone. Remaining concerns regarding the procedure include (1) the generally poor understanding of the mechanisms governing sewer leakage, which can hamper reliable prior information on exfiltration; (2) the currently low measurement precision of sewer tracer studies, which might only allow for the detection of large leaks; and (3) the need for numerical implementation of the Bayesian inference procedure, which requires careful tuning and long computation times. In general, we were able to demonstrate that the incorporation of prior information through a Bayesian procedure adds significant value to experimental design, especially in situations with few “hard” data but good site‐specific knowledge, which is common in water resources research.
A dual active‐restrictive approach to incorporating environmental flow targets into existing reservoir operation rules
Authors: Shiau Jenq‐Tzong , Wu Fu‐Chun
Published: August 2010

Environmental flow schemes may be implemented through active or restrictive strategies. The former may be applied via reservoir releases, and the latter can be executed by reducing water demands. We present a dual active‐restrictive approach to devising the optimal reservoir operation rules that aim to secure off‐stream water supplies while maximizing environmental benefits. For the active part, a multicomponent environmental flow target (including the minimum and monthly flows) is incorporated in the operation rules. For the restrictive counterpart, we use a novel demands partitioning and prioritizing (DPP) approach to reallocating the demands of various sectors. The DPP approach partitions the existing off‐stream demand and newly incorporated environmental demand and reassembles the two as the first‐ and second‐priority demands. Water is reallocated to each demand according to the ratios derived from the prioritized demands. The proposed approach is coupled with a multicriteria optimization framework to seek the optimal operation rules for the existing Feitsui Reservoir system (Taiwan) under various scenarios. The best overall performance is achieved by an optimal dual strategy whose operational parameters are all determined by optimization. The optimal environmental flow target may well be a top‐priority constant base flow rather than the variable quantities. The active strategy would outperform the restrictive one. For the former, a top‐priority base flow target is essential; for the latter, the off‐stream demand can become vanishingly small in compensation for the eliminated base flow target, thus promoting the monthly flow target as nearly the top‐priority demand. For either the active or restrictive strategy, a prioritized environmental flow demand would provide a path toward the optimal overall performance. A significantly improved overall performance over the existing operation rules is unlikely if the active and restrictive parameters are both favorable to the off‐stream demand.
Function-specific response to depletion of microbial diversity
Authors: Peter Hannes , Beier Sara , Bertilsson Stefan , Lindström Eva S , Langenheder Silke , Tranvik Lars J
Published: August 2010

Recent meta-analyses suggest that ecosystem functioning increases with biodiversity, but contradictory results have been presented for some microbial functions. Moreover, observations of only one function underestimate the functional role of diversity because of species-specific trade-offs in the ability to carry out different functions. We examined multiple functions in batch cultures of natural freshwater bacterial communities with different richness, achieved by a dilution-to-extinction approach. Community composition was assessed by molecular fingerprinting of 16S rRNA and chitinase genes, representing the total community and a trait characteristic for a functional group, respectively. Richness was positively related to abundance and biomass, negatively correlated to cell volumes and unrelated to maximum intrinsic growth rate. The response of chitin and cellulose degradation rates depended on the presence of a single phylotype. We suggest that species identity and community composition rather than richness matters for specific microbial processes.
Synthesized Speech Output and Children: A Scoping Review
Authors: Drager Kathryn D. R. , Reichle Joe , Pinkoski Carrie
Published: August 2010

Purpose

Many computer-based augmentative and alternative communication systems in use by children have speech output. This article (a) provides a scoping review of the literature addressing the intelligibility and listener comprehension of synthesized speech output with children and (b) discusses future research directions.

Method

Studies investigating synthesized speech intelligibility and/or comprehension with children as listeners were systematically identified and coded according to their objectives and methodology.

Results

Ten studies were identified. They were organized according to the following variables: intelligibility variables related to the stimuli (context and rate), intelligibility variables related to aspects of the listener (age of the child, the language or languages spoken by the listener, experience, and practice effects), and comprehension. Each of these factors—and the research support with child participants—was discussed.

Conclusions

Overall, there is a paucity of research investigating synthesized speech for use with children. Available evidence suggests that children produce similar trends but lower levels of intelligibility performance when compared with adults. Future areas of applied research are required to adequately define this relationship and the variables that may contribute to improving the intelligibility and comprehension of synthesized speech for children.
Assignment of near-edge x-ray absorption fine structure spectra of metalloporphyrins by means of time-dependent density-functional calculations
Authors: Schmidt Norman Anja , Fink Rainer , Hieringer Wolfgang
Published: August 2010

The C 1s and N 1s near-edge x-ray absorption fine structure (NEXAFS) spectra of three prototype tetraphenyl porphyrin (TPP) molecules are discussed in the framework of a combined experimental and theoretical study. We employ time-dependent density-functional theory (TDDFT) to compute the NEXAFS spectra of the open- and closed-shell metalloporphyrins CoTPP and ZnTPP as well as the free-base 2HTPP in realistic nonplanar conformations. Using Becke’s well-known half-and-half hybrid functional, the computed core excitation spectra are mostly in good agreement with the experimental data in the low-energy region below the appropriate ionization threshold. To make these calculations feasible, we apply a new, simple scheme based on TDDFT using a modified single-particle input spectrum. This scheme is very easy to implement in standard codes and allows one to compute core excitation spectra at a similar cost as ordinary UV/vis spectra even for larger molecules. We employ these calculations for a detailed assignment of the NEXAFS spectra including subtle shifts in certain peaks of the N 1s spectra, which depend on the central coordination of the TPP ligand. We furthermore assign the observed NEXAFS resonances to the individual molecular subunits of the investigated TPP molecules.
Silver/silicon nanostructure for surface-enhanced fluorescence of Ln3+ (LnNd, Ho, and Er)
Authors: Zhuo Shu-Juan , Shao Ming-Wang , Cheng Liang , Que Rong-Hui , Ma Dorthy Duo Duo , Lee Shuit-Tong
Published: August 2010

The surface-enhanced fluorescence of lanthanide ions (neodymium ions Nd3+, holmium ions Ho3+, and erbium ions Er3+) owing to resonant plasmons oscillation on the surface of Ag/Si nanostructure was described. In the presence of Ag/Si nanomaterials, the fluorescence peaks were significantly enhanced, which resulted in a typical 185-fold enhancement at 592 nm for Nd3+, 82-fold at 550 nm for Ho3+, and 80-fold at 533 nm for Er3+ at the concentration of 0.05 M. This Ag/Si nanostructure had larger enhancement factor than that caused by unsupported Ag nanoparticles, which might be attributed to the local field overlap originated from the closed and fixed Ag nanoparticles on silicon nanowires.
Fe–Pd thin films as a model system for self-organized exchange coupled nanomagnets
Authors: Schied T. , Lotnyk A. , Zamponi C. , Kienle L. , Buschbeck J. , Weisheit M. , Holzapfel B. , Schultz L. , Fähler S.
Published: August 2010

In equilibrium the Fe–Pd system on the iron rich side of the phase diagram demixes into Fe and L10-ordered FePd. Here, we examine the suitability of the demixing process for self-organized formation of exchange coupled thin film magnets. In this way the benefit of the high magnetization of Fe is combined with the high magnetocrystalline anisotropy of FePd. By using combinatorial methods the influence of composition and thickness on structure, microstructure, and magnetic properties is analyzed. Experiments show the different thermodynamic and kinetic conditions required for demixing and ordering. In particular, for nanostructures the interface energy during demixing must be considered.
Performance of Z-type hexagonal ferrite core under demagnetizing and external static fields
Authors: Kato Tomotsugu , Mikami Hideto , Noguchi Shin
Published: August 2010

The effects of a demagnetizing field and an external static magnetic field on the effective Snoek’s product of textured Z-type hexagonal ferrite, which is the product of effective susceptibility and resonance frequency, were examined in order to apply the Z-type hexagonal ferrite to high-frequency devices. As a result, the demagnetizing field due to the thin plate geometry increased the resonance frequency and the effective Snoek’s product when a high-frequency magnetic field was applied parallel to the c-plane of the Z-type hexagonal ferrite. Moreover, the resonance frequency, effective susceptibility, and effective Snoek’s product of 7.7 GHz, 10.7, and 82.2 GHz, respectively, were obtained when an external magnetic field that was sufficient to saturate the Z-type hexagonal ferrite slab was applied parallel to the c-plane and perpendicular to the high-frequency magnetic field. Furthermore, the Landau–Lifshitz equation suggested that a large Snoek’s product of over 50 GHz could be obtained with an external static field as small as 31 kA/m, which is enough to saturate the Z-type hexagonal ferrite.
ac susceptibility measurement of magnetic markers in suspension for liquid phase immunoassay
Authors: Enpuku K. , Tamai Y. , Mitake T. , Yoshida T. , Matsuo M.
Published: August 2010

ac susceptibility measurement of magnetic markers in solution was performed for the liquid phase detection of biological targets. First, the properties of the magnetic markers were clarified, such as size distribution, frequency dependence of susceptibility, and field dependence of magnetization. Next, we demonstrated a detection method in which we used large polymer beads to immobilize and prolong the Brownian relaxation time of the bound markers. In this method, we could detect the bound markers by the decrease in the susceptibility that they displayed. Using this method, we detected biotin-conjugated polymer beads with avidin-coated Fe3O4 markers. Changes in susceptibility caused by the binding reaction between them were measured with a magnetoresistive sensor. A strong relationship was observed between the decrease in susceptibility and the number of polymer beads, which indicates that the bound markers were detected correctly without the use of the washing process called bound/free separation. The sensitivity of the system was estimated to be as high as 1.3×10−16 mol/ml in terms of the molecular-number concentration of the markers. The binding process was also discussed from the dependence of the signal on the incubation time.
Axial polarizers based on dichroic liquid crystals
Authors: Nersisyan Sarik , Tabiryan Nelson , Steeves Diane M. , Kimball Brian R.
Published: August 2010

Polarizers capable of producing linearly polarized beams with axial (radial and azimuthal) symmetry have been fabricated with the aid of a dichroic liquid crystal. Photoalignment was achieved using a printing technique to reduce the UV exposure time required for production of axially aligning substrates from 1 h, typical for direct writing techniques, to 10 min. The polarizing features of axial polarizers and their pairs are characterized and their differences outlined. We demonstrate that the transmission switching contrast of an axial polarizer/analyzer pair, comprised of an electrically controlled liquid crystal cell, is comparable to conventional systems with linear polarizers. The opportunities for using axial polarizers for polarization imaging, sensor protection, and nonlinear optics are discussed. Particularly, we show that the technology could reduce the fluence of a laser beam on an optical sensor without affecting imaging.
Effect of pre-existing disorder on surface amorphization in GaN
Authors: Azarov A. Yu. , Titov A. I. , Kucheyev S. O.
Published: August 2010

Single crystal GaN epilayers with pre-existing surface disordered layers are bombarded at room temperature with 40 and 100 keV P ions. Stable lattice defects are studied by Rutherford backscattering/channeling spectrometry. Results show that the rate of planar surface amorphization is independent of the concentration of pre-existing defects near the amorphous/crystalline (a/c) interface. In contrast, the formation of stable defects in the crystal bulk in the vicinity of an a/c interface is influenced by the presence of the interface. These experimental observations suggest that the a/c interface, as compared to stable bulk damage, is a more efficient sink for mobile point defects with respect to both processes of point defect recombination and trapping.
Spin-injection device prospects for half-metallic Fe3O4:Al0.1Ga0.9As interfaces
Authors: Mansell R. , Laloë J.-B. , Holmes S. N. , Wong P. K. J. , Xu Y. B. , Farrer I. , Jones G. A. C. , Ritchie D. A. , Barnes C. H. W.
Published: August 2010

Electrical spin-injection across the Fe3O4:Al0.1Ga0.9As interface has been measured. We quantify this effect in an In0.2Ga0.8As:GaAs spin-light emitting diode optical device. The optical polarization signal is maintained from 4.2 up to 200 K without influence of the metal–insulator Verwey transition in the bulk of the Fe3O4 film. An incomplete oxidation at the interface may be detrimental for this device, as it has a similar spin-injection efficiency to that of Fe:Al0.1Ga0.9As. Ambient temperature operation of this device may be possible although the present polarization levels remain too low for practical spintronic applications. We demonstrate the first step in the integration of molecular beam epitaxy-grown magnetic oxides into III–V semiconductor devices.
Excitation-induced germanium quantum dot formation on Si(100)-(2×1)
Authors: Er Ali Oguz , Elsayed-Ali Hani E.
Published: August 2010

The effect of nanosecond pulsed laser excitation on the self-assembly of Ge quantum dots grown by pulsed laser deposition on Si(100)-(2×1) was studied. In situ reflection high-energy electron diffraction and ex situ atomic force microscopy were used to probe the quantum dot structure and morphology. At room temperature, applying the excitation laser decreased the surface roughness of the grown Ge film. With surface electronic excitation, crystalline Ge quantum dots were formed at 250 °C, a temperature too low for their formation without excitation. At a substrate temperature of 390 °C, electronic excitation during growth was found to improve the quantum dot crystalline quality, change their morphology, and decrease their size distribution almost by half. A purely electronic mechanism of enhanced surface hopping of the Ge adatoms is proposed.
Optimization of low-head, dam-toe, small hydropower projects
Authors: Singal S. K. , Saini R. P. , Raghuvanshi C. S.
Published: August 2010

In most developing countries, such as India, there exists a large amount of hydropower potential. This is especially true in the small hydro plant capacity range of up to 25 MW. Only a small fraction of this potential has been tapped so far, perhaps due to higher per kilowatt installation cost as compared to large hydro. Small hydropower sites can be classified as (i) run-of-river; (ii) canal based, and (iii) dam-toe schemes, depending on their location. Dam-toe schemes need low investment and can be developed in a shorter period of time. In the present study, an attempt has been made to estimate the cost of the low-head, dam-toe, small hydropower schemes. A methodology for cost optimization of such schemes has been developed considering the quantities of various items for each component of the scheme and prevailing prices. Further, to determine financial viability of the scheme at different load factors, sensitivity analysis has also been carried out. It has been found that low-head, dam-toe, small hydropower schemes are financially viable.
Damaged carbon nanotubes get healed by ion irradiation
Authors: Jeet Kiran , Jindal V. K. , Bharadwaj L. M. , Avasthi D. K. , Dharamvir Keya
Published: August 2010

Carbon nanotubes (CNTs) are being used for varied applications. It is therefore important to study their stability under extreme conditions of temperature and irradiation. In this work, we report the stability of CNTs [both single-wall CNTs (SWCNTs) and multiwalled CNTs (MWCNTs)] under irradiation of a carbon ion beam of energy 55 MeV. The irradiated samples were analyzed using Raman spectroscopy. The Raman results indicate the interesting phenomenon of healing or annealing of CNTs under ion beam irradiation. The annealing process appears to begin at the lowest value of fluences and persists for quite a good range of fluence values. As the irradiation dose increases (≈1×1014 ions/cm2) the MWCNTs begin to amorphize whereas the SWCNTs system continues to heal.
Thermoelectric properties of LaFeAsO1−y at low temperature
Authors: Kihou K. , Lee C. H. , Miyazawa K. , Shirage P. M. , Iyo A. , Eisaki H.
Published: August 2010

We have studied the thermoelectric properties of LaFeAsO1−y in the temperature range 10–300 K. The resistivity decreases with carrier doping induced by oxygen deficiency up to y=0.16. On the other hand, the Seebeck coefficient shows a maximum absolute value at a finite doping level. The power factor (PF) and the dimensionless thermoelectric figure of merit (ZT) in y=0.16 are PF=4.1 mW m−1 K−2 at T=75 K and ZT=0.061 at T=125 K. The results indicate that iron pnictides have potential as a good low temperature thermoelectric material.
Atmospheric pressure plasma jets beyond ground electrode as charge overflow in a dielectric barrier discharge setup
Authors: Jiang Nan , Ji Ailing , Cao Zexian
Published: August 2010

With a proper combination of applied voltage and the width of ground electrode, atmospheric pressure plasma jets extending beyond the ground electrode, whether it sits on the downstream or the upstream side, can be equally obtained with a dielectric barrier discharge setup, which can be ascribed to the overflow of deposited charges [J. Appl. Phys. 106, 013308 (2009)]. Here, we show that, by using narrower ground electrodes, such an overflow jet can be successfully launched at a much reduced voltage (down to below 10 kV). Moreover, by using transparent and triadic ground electrodes, development of charge overflow beneath the ground electrode was temporally and spatially resolved. Temporal evolution of discharge currents measured on the severed ground electrode helps establish the propagation dynamics of discharges along the dielectric surface beneath ground electrode, and also reinforces the conception that the streamer’s head is in connection to the active electrode via a conducting channel. A small propagation velocity of 3.3×103 m/s was measured for the “overflow” jet inside the dielectric tube. The availability of such overflow jets is enormously advantageous concerning their application to living bodies, to which the high voltage at active electrode is lethally dangerous.
On the applicability of a few level rate equation model to the determination of exciton versus biexciton kinetics in quasi-zero-dimensional structures
Authors: Sęk G. , Musiał A. , Podemski P. , Misiewicz J.
Published: August 2010

Hereby, we present a few level rate equation model in a context of the interpretation of excitation power dependent exciton and biexciton emission intensity from single quantum-dot-like structures. We emphasize that it not only allows identifying the excitonic and biexcitonic emission from one quasi-zero-dimensional object, but gives also an insight into the kinetics of the carriers confined in the system (both the internal dynamics of the exciton within its fine structure and the relative exciton to biexciton lifetimes ratio), the regime of the confinement itself and the importance of the higher energy levels occupation. Eventually, there are presented and discussed examples of the rate equation model application for an analysis of the experimental data for several kinds of epitaxial nanostructures.
Direct determination of the crystallographic orientation of graphene edges by atomic resolution imaging
Authors: Neubeck S. , You Y. M. , Ni Z. H. , Blake P. , Shen Z. X. , Geim A. K. , Novoselov K. S.
Published: August 2010

In this letter, we show how high-resolution scanning tunneling microscopy (STM) imaging can be used to reveal that certain edges of micromechanically exfoliated single layer graphene crystals on silicon oxide follow either zigzag or armchair orientation. Using the cleavage technique, graphene flakes are obtained that very often show terminating edges seemingly following the crystallographic directions of the underlying honeycomb lattice. Performing atomic resolution STM-imaging on such flakes, we were able to directly prove this assumption. Raman imaging carried out on the same flakes further validated our findings.
Theoretical modeling of refractive index in ion implanted LiNbO3 waveguides
Authors: Yin Jiao-Jian , Lu Fei , Ming Xian-Bing , Ma Yu-Jie , Huang Meng-bing
Published: August 2010

A theoretical model is developed to evaluate the roles of various mechanisms, including the molar polarization and molar volume, the spontaneous polarization and the photoelastic effect, for the modifications of refractive indices in ion-implanted LiNbO3 waveguides. Based on the model, numerical calculations of refractive indices as a function of the lattice damage level in LiNbO3 crystals of different crystalline orientations (X, Y, and Z), are performed, with results in a good agreement with experimental data. The analysis indicates that the spontaneous polarization, the molar polarization, and molar volume play important roles in determining the index profiles in ion implanted LiNbO3. In addition, the contribution of the strain-induced photoelastic effect has been identified for different damage levels.
Effect of composition on damage accumulation in ternary ZnO-based oxides implanted with heavy ions
Authors: Azarov A. Yu. , Svensson B. G. , Hallén A. , Du X. L. , Kuznetsov A. Yu.
Published: August 2010

Thin films of wurtzite MgxZn1−xO (x≤0.3) grown by molecular beam epitaxy and wurtzite CdxZn1−xO (x≤0.05) grown by metal organic chemical vapor deposition were implanted at room temperature with 150 keV Er+ ions and 200 keV Au+ ions in a wide dose range. Damage accumulation was studied by Rutherford backscattering/channeling spectrometry. Results show that the film composition affects the damage accumulation behavior in both MgZnO and CdZnO dramatically. In particular, increasing the Mg content in MgZnO results in enhanced damage accumulation in the region between the bulk and surface damage peaks characteristically distinguished in the pure ZnO. However, the overall damage accumulation in MgZnO layers, as well as in pure ZnO, exhibits saturation with increasing ion dose and MgZnO cannot be amorphized even at the highest ion dose used (3×1016 Er/cm2). Increasing the Cd content in CdZnO affects the saturation stage of the damage accumulation and leads to an enhancement of damage production in both Cd and Zn sublattices.
Design of an electrically pumped SiGeSn/GeSn/SiGeSn double-heterostructure midinfrared laser
Authors: Sun G. , Soref R. A. , Cheng H. H.
Published: August 2010

This paper presents the conception, modeling, and simulation of a silicon-based group-IV semiconductor injection laser diode in which the GeSn-alloy active region has a direct band gap wavelength in the 1.8 to 3.0 μm midwave infrared for 6%–12% α-Sn. The strain-free monolithic P-type semiconductor/Intrinsic semiconductor/N-type semiconductor (PIN) bulk heterostructure, grown lattice matched upon a relaxed GeSn-buffer on silicon-on-insulator, is believed to be manufacturable in a complementary metal-oxide semiconductor fab. Detailed modeling is given for the type-I band offsets, carrier lifetimes, infrared gain profile and laser threshold current density Jth in a Fabry–Perot cavity having 20–100 cm−1 loss. The laser’s temperature of operation is determined by a combination of the radiative lifetime and the nonradiative lifetime due to unwanted Auger electron-hole recombination. If we keep Jth below 10 kA/cm2, then we find that this laser requires cooling in the 100–200 K range, whereas Jth at 300 K appears to be too high for a practical device. However, the GeSn quantum-well laser diode does offer a pathway to room-temperature operation.
Bulk sensitive x-ray absorption and magnetic circular dichroism investigation of Mn- and Co-doped ZnO thin films
Authors: Di Trolio A. , Larciprete R. , Turchini S. , Zema N.
Published: August 2010

Bulk sensitive L2,3 x-ray magnetic circular dichroism spectra were measured in transmission on Mn- and Co-doped ZnO thin films grown by pulsed laser deposition on soft x-ray transparent silicon nitride membranes. The absorption spectra line shapes support that Mn and Co divalent ions substitute Zn ions ruling out the hint of cluster formation. The lack of dichroic signal at the Mn and Co-edges in such bulk sensitive measurements indicates that the ferromagnetism witnessed by vibrating sample magnetometry measurements could arise from delocalized magnetic moments, due to itinerant electrons associated with defects.
Electrochemical hydrogen termination of boron-doped diamond
Authors: Hoffmann René , Kriele Armin , Obloh Harald , Hees Jakob , Wolfer Marco , Smirnov Waldemar , Yang Nianjun , Nebel Christoph E.
Published: August 2010

Boron-doped diamond is a promising transducer material for numerous devices which are designed for contact with electrolytes. For optimized electron transfer the surface of diamond needs to be hydrogen terminated. Up to now H-termination of diamond is done by plasma chemical vapor deposition techniques. In this paper, we show that boron-doped diamond can be H-terminated electrochemically by applying negative voltages in acidic solutions. Electrochemical H-termination generates a clean surface with virtually no carbon–oxygen bonds (x-ray photoelectron spectroscopy), a reduced electron affinity (scanning electron microscopy), a highly hydrophobic surface (water contact angle), and a fast electron exchange with Fe(CN)6−3/−4 (cyclic voltammetry).
Comatic aberration-induced wavy vortex in gas
Authors: Chu Hong-Yu , Lin Shang-Bin , Ko Chang-Rong
Published: August 2010

We investigate the evolution of laser-induced wavy vortex at 460 torr nitrogen gas environment. We show that Rayleigh–Taylor instability and Kelvin–Helmholtz instability are not the causes of the growth of the wavy vortex. Normal diffusion inducing the growth of the ripple-type perturbation is identified. The ratio of the perturbation amplitude to the wavelength of perturbation is found with 0.16. Through a quick estimation, measurements show the consistent scaling relations. We further show that the comatic aberration is suspected to be responsible for the asymmetric rarefaction wave, which triggers Kelvin–Helmholtz instability and induces the wavy vortex.
Resistive switching transition induced by a voltage pulse in a Pt/NiO/Pt structure
Authors: Hwang Inrok , Lee Myung-Jae , Buh Gyoung-Ho , Bae Jieun , Choi Jinsik , Kim Jin-Soo , Hong Sahwan , Kim Yeon Soo , Byun Ik-Su , Lee Seung-Woong , Ahn Seung-Eon , Kang Bo Soo , Kang Sung-Oong , Park Bae Ho
Published: August 2010

We have observed a switching transition between bistable memory switching and monostable threshold switching in Pt/NiO/Pt structure. Bistable memory switching could be changed to monostable threshold switching by applying a positive electrical pulse with height of 2 V and width between 10−2 and 10−4 s. The change is reversible by applying a negative electrical pulse with the same height and width. By considering polarity- and width-dependence of the switching transition and compositional difference on electrical properties in NiOx, we have proposed a model in which the migration of oxygen ions (O2−) is responsible for the switching transition in Pt/NiO/Pt structures.
Switchable metamaterial reflector/absorber for different polarized electromagnetic waves
Authors: Zhu Bo , Feng Yijun , Zhao Junming , Huang Ci , Jiang Tian
Published: August 2010

We demonstrate a controllable electromagnetic wave reflector/absorber for different polarizations with metamaterial involving electromagnetic resonant structures coupled with diodes. Through biasing at different voltages to turn ON and OFF the diodes, we are able to switch the structure between nearly total reflection and total absorption of a particularly polarized incident wave. By arranging orthogonally orientated resonant cells, the metamaterial can react to different polarized waves by selectively biasing the corresponding diodes. Both numerical simulations and microwave measurements have verified the performance.
Bioavailability of copper and zinc to poplar and microorganisms in a biosolids-amended soil
Authors: Jeyakumar P. , Loganathan P. , Sivakumaran S. , Anderson C. W. N. , McLaren R. G.
Published: August 2010

The effects of high concentrations of copper (Cu) and zinc (Zn) in a soil treated with biosolids previously spiked with these metals on poplar (Populus deltoides × yunnanensis) were investigated in a pot trial. The total soil metal concentrations in the treatments were 12, 46, 137, and 226 mg Cu/kg and 25, 141, 433, and 686 mg Zn/kg. Copper accumulation was lower in poplar leaves than Zn and the maximum bioconcentration factor was 0.8 for Cu and 10 for Zn. Copper was not found to be toxic to plants at any level of application or to mycorrhiza up to 137 mg/kg, but it was found to be toxic to soil microorganisms at all levels of Cu addition. Copper application increased mycorrhiza colonisation up to 137 mg Cu/kg and root dry matter at 226 mg Cu/kg, but had no effect on leaf dry matter. Increasing Zn rate decreased all plant and soil parameters. Lower percentages of Cu in the soil exchangeable fraction, and a lower Cu2+ concentrations in soil solution relative to Zn indicated lower bioavailability of Cu. Dehydrogenase activity was reduced by 50% at total solution-phase Cu and Zn concentrations of 0.1 and 27 mg/L, respectively, and solid-phase exchangeable Cu and Zn concentrations of 5 and 169 mg/kg, respectively.
Boron contents and solubility in Australian fly ashes and its uptake by canola (Brassica napus L.) from the ash-amended soils
Authors: Manoharan V. , Yunusa I. A. M. , Loganathan P. , Lawrie R. , Murray B. R. , Skilbeck C. G. , Eamus D.
Published: August 2010

Phytotoxicity due to excessive boron (B) uptake by plants impedes routine agronomic utilisation of coal fly ash. We assessed 11 fly ashes (pH 3.14–10.77) having total B content (Bt) of 12–136 mg/kg, of which 20–30% was hot water soluble (Bs) in the acidic ashes (pH <5) and 5–10% in the alkaline ashes, for their potential to supply B to plants and their risk associated with phytotoxicity. We found the Bs/Bt to be negatively correlated (R2 = 0.63**, N = 11) with ash pH.
We conducted two pot trials in which canola was grown in soils amended with fly ash. In the first trial, an alkaline fly ash (Bt 66 mg/kg) was incorporated at 5 rates of up to 625 Mg/ha into the top 50 mm of 2 acidic soils in 0.30-m-long intact cores, and sown with canola. Boron concentration in leaves at flowering reached the phytotoxic threshold, and both plant growth and seed yield were reduced, only at 625 Mg/ha. In the second trial, 4 fly ashes (pH 3.29–10.77, Bt 12–127 mg/kg) were incorporated at 4 rates of up to 108 Mg/ha into the top 0.10 m of 2 acidic soils in 1.0-m-long intact cores and then sown with canola. Ashes with highest Bt, when applied at 108 Mg/ha, increased B concentration in the topsoil only. Of the 2 ashes with the highest Bt, only that which produced low soil pH and applied at 108 Mg/ha increased B concentration in the shoot, but was still below phytotoxic threshold. The results suggest that B derived from these ashes may not cause phytotoxicity and excessive soil B accumulation if the ashes are applied at modest rates (<36 Mg/ha) to the topsoil layers.
Farnesylated Nuclear Proteins Kugelkern and Lamin Dm0 Affect Nuclear Morphology by Directly Interacting with the Nuclear Membrane
Authors: Polychronidou Maria , Hellwig Andrea , Grosshans Jörg
Published: August 2010

Nuclear shape changes are observed during a variety of developmental processes, pathological conditions, and ageing. The mechanisms underlying nuclear shape changes in the above-mentioned situations have mostly remained unclear. To address the molecular mechanism behind nuclear shape changes, we analyzed how the farnesylated nuclear envelope proteins Kugelkern and lamin Dm0 affect the structure of the nuclear membrane. We found that Kugelkern and lamin Dm0 affect nuclear shape without requiring filament formation or the presence of a classical nuclear lamina. We also could show that the two proteins do not depend on a group of selected inner nuclear membrane proteins for their localization to the nuclear envelope. Surprisingly, we found that farnesylated Kugelkern and lamin Dm0 protein constructs change the morphology of protein-free liposomes. Based on these findings, we propose that farnesylated proteins of the nuclear membrane induce nuclear shape changes by being asymmetrically inserted into the phospholipid bilayer via their farnesylated C-terminal part.
The Double-stranded RNA–dependent Protein Kinase Differentially Regulates Insulin Receptor Substrates 1 and 2 in HepG2 Cells
Authors: Yang Xuerui , Nath Aritro , Opperman Michael J. , Chan Christina
Published: August 2010

Initially identified to be activated upon virus infection, the double-stranded RNA–dependent protein kinase (PKR) is best known for triggering cell defense responses by phosphorylating eIF-2α, thus suppressing RNA translation. We as well as others showed that the phosphorylation of PKR is down-regulated by insulin. In the present study, we further uncovered a novel function of PKR in regulating the IRS proteins. We found that PKR up-regulates the inhibitory phosphorylation of IRS1 at Ser312, which suppresses the tyrosine phosphorylation of IRS1. This effect of PKR on the phosphorylation of IRS1 is mediated by two other protein kinases, JNK and IKK. In contrast, PKR regulates IRS2, another major IRS family protein in the liver, at the transcriptional rather than the posttranslational level, and this effect is mediated by the transcription factor, FoxO1, which has been previously shown to be regulated by insulin and plays a significant role in glucose homeostasis and energy metabolism. In summary, we found for the first time that initially known as a virus infection response gene, PKR regulates the upstream central transmitters of insulin signaling, IRS1 and IRS2, through different mechanisms.
A Microeconometric Analysis of Adapting Portfolios to Climate Change: Adoption of Agricultural Systems in Latin America
Authors: Seo S. Niggol
Published: August 2010

This paper develops a microeconometric analysis of adapting portfolios in response to climate change using information on South American farmers' adoption of agricultural systems taken from approximately 2,000 household surveys. The results show that farmers in a hotter climate prefer a mixed system over specialized systems either in crops or livestock. Under a hot and dry scenario, the land values of all three systems would fall, but the damage would be much smaller in the mixed system (−10%) than for the farms specializing in crops (−20%). Farmers are predicted to lose 8% of their land's value under the Canadian Climatic Center (CCC) scenario, but only 2% under the Parallel Climate Model (PCM). Losses would increase to 18% if they do not adapt.
Ultra-fast FFT protein docking on graphics processors
Authors: Ritchie David W. , Venkatraman Vishwesh
Published: August 2010

Motivation: Modelling protein–protein interactions (PPIs) is an increasingly important aspect of structural bioinformatics. However, predicting PPIs using in silico docking techniques is computationally very expensive. Developing very fast protein docking tools will be useful for studying large-scale PPI networks, and could contribute to the rational design of new drugs.

Results: The Hex spherical polar Fourier protein docking algorithm has been implemented on Nvidia graphics processor units (GPUs). On a GTX 285 GPU, an exhaustive and densely sampled 6D docking search can be calculated in just 15 s using multiple 1D fast Fourier transforms (FFTs). This represents a 45-fold speed-up over the corresponding calculation on a single CPU, being at least two orders of magnitude times faster than a similar CPU calculation using ZDOCK 3.0.1, and estimated to be at least three orders of magnitude faster than the GPU-accelerated version of PIPER on comparable hardware. Hence, for the first time, exhaustive FFT-based protein docking calculations may now be performed in a matter of seconds on a contemporary GPU. Three-dimensional Hex FFT correlations are also accelerated by the GPU, but the speed-up factor of only 2.5 is much less than that obtained with 1D FFTs. Thus, the Hex algorithm appears to be especially well suited to exploit GPUs compared to conventional 3D FFT docking approaches.

Availability:  http://hex.loria.fr/ and http://hexserver.loria.fr/

Contact:  dave.ritchie@loria.fr

Supplementary information:  Supplementary data are available at Bioinformatics online.
Soluble receptor of advanced glycation end products levels are related to ischaemic aetiology and extent of coronary disease in chronic heart failure patients, independent of advanced glycation end products levels
Authors: Raposeiras‐Roubín Sergio , Rodiño‐Janeiro Bruno K. , Grigorian‐Shamagian Lilian , Moure‐González María , Seoane‐Blanco Ana , Varela‐Román Alfonso , Alvarez Ezequiel , González‐Juanatey José R.
Published: August 2010

Aims

Knowledge of the role of advanced glycation end products (AGE), their receptor (RAGE), and the receptor's soluble form (sRAGE), in heart failure (HF) is very limited. We evaluated the clinical role of the AGE–RAGE system in HF and in particular any association it might have with ischaemic aetiology.

Methods and results

We measured fluorescent AGE, glycated albumin and sRAGE in 103 patients with chronic HF. We showed that sRAGE but not AGE was related to ischaemic aetiology (1638.3 ± 207.4 ischaemic vs. 1065.1 ± 94.2 pg/mL non‐ischaemic group; P =0.016) independent of age, sex, diabetes, renal function, clinical severity, or other variables (OR: 1.091; 95% CI (confidence interval): 1.032–1.153; P =0.007). Moreover, sRAGE was directly associated with extent of coronary disease (OR for three vessel disease compared with non‐coronary lesions: 1.186; 95% CI: 1.065–1.322; P =0.002). We also found a correlation between sRAGE and severity of HF, which increased with New York Heart Association (NYHA) class (741.9 ± 88.9 pg/mL in class 1, 1195.9 ± 113.2 pg/mL in class II, and 1724.8 ± 245.7 pg/mL in class III (P < 0.05)) and brain natriuretic peptide (BNP) levels (667.4 ± 68.0 vs. 1344.5 ± 126.0 pg/mL for BNP < and ≥400 pg/mL, respectively).

Conclusion

sRAGE is an indicator of chronic heart failure severity and an independent marker of coronary artery disease and its severity in patients with CHF.
On the relationship between squid and the environment: artisanal jigging for Loligo plei at São Sebastião Island (24°S), southeastern Brazil
Authors: Postuma Felippe A. , Gasalla Maria A.
Published: August 2010

Postuma, F. A., and Gasalla, M. A. 2010. On the relationship between squid and the environment: artisanal jigging for Loligo plei at São Sebastião Island (24°S), southeastern Brazil. – ICES Journal of Marine Science, 67: 1353–1362. The squid Loligo plei concentrates in the southeastern Brazil Bight, where it has traditionally supported small-scale fisheries around São Sebastião Island (SSI). Sea surface temperature (SST), chlorophyll-a (Chl a), windspeed, wave height, rainfall, and lunar phase are related to fishing records and to the results of a survey of local fishers to investigate how they believe environmental variables might affect catches of L. plei. Daily fishery-dependent data over the years 2005–2009 were obtained from a fishing cooperative and were matched with satellite and meteorological forecast data. Generalized linear models were used to explore the significance of environmental variables in relation to variability in catch and catch per unit effort (cpue). Squid are fished with jigs in water shallower than 20 m, generally where SST is warmer and Chl a and windspeed are lower. Cpue and monthly catches decreased from 2005 to 2008, followed by a slight increase in 2009. The correlations between fishery and environmental data relate well to fishers' oceanological knowledge, underscoring the potential of incorporating such knowledge into evaluations of the fishery.
Host and Nonhost Resistance in Medicago–Colletotrichum Interactions
Authors: Jaulneau Valérie , Cazaux Marc , Hoi Joanne Wong Sak , Fournier Sylvie , Esquerré-Tugayé Marie-Thérèse , Jacquet Christophe , Dumas Bernard
Published: August 2010

Medicago truncatula lines resistant (A17) or susceptible (F83005.5) to the alfalfa pathogen Colletotrichum trifolii were used to compare defense reactions induced upon inoculation with C. trifolii or with the nonadapted pathogens C. lindemuthianum and C. higginsianum. Nonadapted Colletotrichum spp. induced a hypersensitive response (HR)-like reaction similar to the one induced during the host-incompatible interaction. Molecular analyses indicated an induction of PR10 and chalcone synthase genes in host and nonhost interactions but delayed responses were observed in the F83005.5 line. The clste12 penetration-deficient C. lindemuthianum mutant induced an HR and defense gene expression, showing that perception of nonadapted strains occurs before penetration of epidermal cells. Cytological and transcriptomic analyses performed upon inoculation of near-isogenic M. truncatula lines, differing only at the C. trifolii resistance locus, Ct1, with the nonadapted Colletotrichum strain, showed that nonhost responses are similar in the two lines. These included a localized oxidative burst, accumulation of fluorescent compounds, and transient expression of a small number of genes. Host interactions were characterized by a group of defense and signaling-related genes induced at 3 days postinoculation, associated with an accumulation of salicylic acid. Together, these results show that M. truncatula displays a rapid and transient response to nonadapted Colletotrichum strains and that this response is not linked to the C. trifolii resistance locus.
TheUstilago maydisForkhead Transcription Factor Fox1 Is Involved in the Regulation of Genes Required for the Attenuation of Plant Defenses During Pathogenic Development
Authors: Zahiri Alexander , Heimel Kai , Wahl Ramon , Rath Magnus , Kämper Jörg
Published: August 2010

Ustilago maydis is a plant-pathogenic fungus that establishes a biotrophic relationship with its host plant, Zea mays. The pathogenic stage of U. maydis is initiated by the fusion of two haploid cells, resulting in the formation of a dikaryotic hypha that invades the plant cell. The switch from saprophytic, yeast-like cells to the biotrophic hyphae requires the complex regulation of a multitude of biological processes to constitute the compatible host–fungus interaction. Transcriptional regulators involved in the establishment of the infectious dikaryon and penetration of the host tissue have been identified; however, regulators required during the post-penetration stages remained to be elucidated. In this study, we report the identification of a U. maydis forkhead transcription factor, Fox1, which is exclusively expressed during biotrophic development. Deletion of fox1 results in reduced virulence and impaired tumor development. The Δfox1 hyphae induce the accumulation of H2O2in and around infected cells and a maize defense response phenotypically represented by the encasement of proliferating hyphae in a cellulose-containing matrix. The phenotype can be attributed to the fox1-dependent deregulation of several effector genes that are linked to pathogenic development and host defense suppression.
Male response to historical and geographical variation in bird song
Authors: Derryberry Elizabeth P.
Published: August 2010

In many species, individuals discriminate among sexual signals of conspecific populations in the contexts of mate choice and male–male competition. Differences in signals among populations (geographical variation) are in part the result of signal evolution within populations (temporal variation). Understanding the relative effect of temporal and geographical signal variation on signal salience may therefore provide insight into the evolution of behavioural discrimination. However, no study, to my knowledge, has compared behavioural response to historical signals with response to current signal variation among populations. Here, I measured the response of male white-crowned sparrows (
Zonotrichia leucophrys
) to historical songs compared with current songs from their local population, a nearby non-local population and a distant population. Males responded most strongly to current local songs, less, but equally, to historical local and current non-local songs, and least to songs of the distant population. Moreover, response to both temporal and geographical variation in song was proportional to how much songs differed acoustically from current local songs. Signal evolution on an ecological time scale appears to have an effect on signal salience comparable to differences found between current neighbouring populations, supporting the idea that behavioural discrimination among learned signals of conspecific populations can evolve relatively rapidly.