bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel spectro-electrochemical cell for in situ/operando observation of common composite electrode with liquid electrolyte by X-ray absorption spectroscopy in the tender X-ray region
Authors: Nakanishi Koji , Kato Daisuke , Arai Hajime , Tanida Hajime , Mori Takuya , Orikasa Yuki , Uchimoto Yoshiharu , Ohta Toshiaki , Ogumi Zempachi
Published: August 2014

A novel spectro-electochemical cell for X-ray absorption spectroscopy in the tender X-ray region (TX-XAS) was designed and fabricated to investigate the electrochemical behavior of common battery materials with liquid electrolytes under in situ/operando conditions. The cell has several unique features, such as high X-ray transmittance, high signal to noise ratio, and high vacuum tightness. These features enable us quick and reliable XAS measurements. Operando P K-edge XAS measurements of an olivine-type LiFePO4 composite positive electrode were carried out to clarify its phosphorus environment during the electrochemical charging process. Results of spectral analysis show that there is no significant change in the oxidation state of phosphorus and in the coordination of the phosphate anions in the charging process, but a closer look of the consecutive XAS spectra suggests the shrinkage of the PO4 cage during the charging process, and the structural changes in a biphasic manner. These results demonstrate the usefulness of the cell for in situ/operando TX-XAS observations of light elements in practical batteries.
Investigation of the hard x-ray background in backlit pinhole imagers
Authors: Fein J. R. , Peebles J. L. , Keiter P. A. , Holloway J. P. , Klein S. R. , Kuranz C. C. , Manuel M. J.-E. , Drake R. P.
Published: August 2014

Hard x-rays from laser-produced hot electrons (>10 keV) in backlit pinhole imagers can give rise to a background signal that decreases signal dynamic range in radiographs. Consequently, significant uncertainties are introduced to the measured optical depth of imaged plasmas. Past experiments have demonstrated that hard x-rays are produced when hot electrons interact with the high-Z pinhole substrate used to collimate the softer He-α x-ray source. Results are presented from recent experiments performed on the OMEGA-60 laser to further study the production of hard x-rays in the pinhole substrate and how these x-rays contribute to the background signal in radiographs. Radiographic image plates measured hard x-rays from pinhole imagers with Mo, Sn, and Ta pinhole substrates. The variation in background signal between pinhole substrates provides evidence that much of this background comes from x-rays produced in the pinhole substrate itself. A Monte Carlo electron transport code was used to model x-ray production from hot electrons interacting in the pinhole substrate, as well as to model measurements of x-rays from the irradiated side of the targets, recorded by a bremsstrahlung x-ray spectrometer. Inconsistencies in inferred hot electron distributions between the different pinhole substrate materials demonstrate that additional sources of hot electrons beyond those modeled may produce hard x-rays in the pinhole substrate.
Gallium phosphide as a new material for anodically bonded atomic sensors
Authors: Dural Nezih , Romalis Michael V.
Published: August 2014

Miniaturized atomic sensors are often fabricated using anodic bonding of silicon and borosilicate glass. Here we describe a technique for fabricating anodically bonded alkali-metal cells using GaP and Pyrex. GaP is a non-birefringent semiconductor that is transparent at alkali-metal resonance wavelengths, allowing new sensor geometries. GaP also has a higher thermal conductivity and lower He permeability than borosilicate glass and can be anodically bonded below 200 °C, which can also be advantageous in other vacuum sealing applications.
Asymmetric steady streaming as a mechanism for acoustic propulsion of rigid bodies
Authors: Nadal François , Lauga Eric
Published: August 2014

Recent experiments showed that standing acoustic waves could be exploited to induce self-propulsion of rigid metallic particles in the direction perpendicular to the acoustic wave. We propose in this paper a physical mechanism for these observations based on the interplay between inertial forces in the fluid and the geometrical asymmetry of the particle shape. We consider an axisymmetric rigid near-sphere oscillating in a quiescent fluid along a direction perpendicular to its symmetry axis. The kinematics of oscillations can be either prescribed or can result dynamically from the presence of an external oscillating velocity field. Steady streaming in the fluid, the inertial rectification of the time-periodic oscillating flow, generates steady stresses on the particle which, in general, do not average to zero, resulting in a finite propulsion speed along the axis of the symmetry of the particle and perpendicular to the oscillation direction. Our derivation of the propulsion speed is obtained at leading order in the Reynolds number and the deviation of the shape from that of a sphere. The results of our model are consistent with the experimental measurements, and more generally explains how time periodic forcing from an acoustic field can be harnessed to generate autonomous motion.
Modeling direct interband tunneling. II. Lower-dimensional structures
Authors: Pan Andrew , Chui Chi On
Published: August 2014

We investigate the applicability of the two-band Hamiltonian and the widely used Kane analytical formula to interband tunneling along unconfined directions in nanostructures. Through comparisons with k·p and tight-binding calculations and quantum transport simulations, we find that the primary correction is the change in effective band gap. For both constant fields and realistic tunnel field-effect transistors, dimensionally consistent band gap scaling of the Kane formula allows analytical and numerical device simulations to approximate non-equilibrium Green's function current characteristics without arbitrary fitting. This allows efficient first-order calibration of semiclassical models for interband tunneling in nanodevices.
Study on in situ calibration for neutron flux monitor in the Large Helical Device based on Monte Carlo calculations
Authors: Nakano Y. , Yamazaki A. , Watanabe K. , Uritani A. , Ogawa K. , Isobe M.
Published: August 2014

Neutron monitoring is important to manage safety of fusion experiment facilities because neutrons are generated in fusion reactions. Monte Carlo simulations play an important role in evaluating the influence of neutron scattering from various structures and correcting differences between deuterium plasma experiments and in situ calibration experiments. We evaluated these influences based on differences between the both experiments at Large Helical Device using Monte Carlo simulation code MCNP5. A difference between the both experiments in absolute detection efficiency of the fission chamber between O-ports is estimated to be the biggest of all monitors. We additionally evaluated correction coefficients for some neutron monitors.
Near-infrared spectroscopy for divertor plasma diagnosis and control in DIII-D tokamak
Authors: Soukhanovskii V. A. , McLean A. G. , Allen S. L.
Published: August 2014

New near infrared (NIR) spectroscopic measurements performed in the DIII-D tokamak divertor plasma suggest new viable diagnostic applications: divertor recycling and low-Z impurity flux measurements, a spectral survey for divertor Thomson scattering (DTS) diagnostic, and Te monitoring for divertor detachment control. A commercial 0.3 m spectrometer coupled to an imaging lens via optical fiber and a InGaAs 1024 pixel array detector enabled deuterium and impurity emission measurements in the range 800–2300 nm. The first full NIR survey identified D, He, B, Li, C, N, O, Ne lines and provided plasma Te, ne estimates from deuterium Paschen and Brackett series intensity and Stark line broadening analysis. The range 1.000–1.060 mm was surveyed in high-density and neon seeded divertor plasmas for spectral background emission studies for λ = 1.064 μm laser-based DTS development. The ratio of adjacent deuterium Paschen-α and Brackett Br9 lines in recombining divertor plasmas is studied for divertor Te monitoring aimed at divertor detachment real-time feedback control.
Ultrahigh-resolution and non-contact diameter measurement of metallic wire using eddy current sensor
Authors: Li Wei , Wang Hongbo , Feng Zhihua
Published: August 2014

This paper proposes a new method using eddy current sensor (ECS) for online non-contact diameter measurement of metallic wires with ultrahigh resolution. A prototype sensor was designed, fabricated, and tested for copper wires with diameters ranging from 1.12 mm to 1.30 mm. A solenoid coil with dimensions of 16 mm long and 2.1 mm in diameter is used as sensing element with a working frequency of 1.3 MHz. With a well-designed bridge, the sensing coil's inductance variation can be detected and the wire's diameter can be calculated. The ECS system demonstrated a dynamic resolution better than 2.2 μm and a static resolution better than 0.42 nm for a wire with a diameter of 1.3 mm. This non-contact method has competitive advantages over other methods in many aspects, especially in terms of measurement resolution.
Three-dimensional direct numerical simulation study of conditioned moments associated with front propagation in turbulent flows
Authors: Yu R. , Lipatnikov A. N. , Bai X. S.
Published: August 2014

In order to gain further insight into (i) the use of conditioned quantities for characterizing turbulence within a premixed flame brush and (ii) the influence of front propagation on turbulent scalar transport, a 3D Direct Numerical Simulation (DNS) study of an infinitely thin front that self-propagates in statistically stationary, homogeneous, isotropic, forced turbulence was performed by numerically integrating Navier-Stokes and level set equations. While this study was motivated by issues relevant to premixed combustion, the density was assumed to be constant in order (i) to avoid the influence of the front on the flow and, therefore, to know the true turbulence characteristics as reference quantities for assessment of conditioned moments and (ii) to separate the influence of front propagation on turbulent transport from the influence of pressure gradient induced by heat release. Numerical simulations were performed for two turbulence Reynolds numbers (50 and 100) and four ratios (1, 2, 5, and 10) of the rms turbulent velocity to the front speed. Obtained results show that, first, the mean front thickness is decreased when a ratio of the rms turbulent velocity to the front speed is decreased. Second, although the gradient diffusion closure yields the right direction of turbulent scalar flux obtained in the DNS, the diffusion coefficient Dt determined using the DNS data depends on the mean progress variable. Moreover, Dt is decreased when the front speed is increased, thus, indicating that the front propagation affects turbulent scalar transport even in a constant-density case. Third, conditioned moments of the velocity field differ from counterpart mean moments, thus, disputing the use of conditioned velocity moments for characterizing turbulence when modeling premixed turbulent combustion. Fourth, computed conditioned enstrophies are close to the mean enstrophy in all studied cases, thus, suggesting the use of conditioned enstrophy for characterizing turbulence within a premixed flame brush.
New insight into power-law behavior of fragment size distributions in the C60 multifragmentation regime
Authors: Qian D. B. , Ma X. , Chen Z. , Li B. , Zhang D. C. , Zhu X. L. , Wen W. Q. , Liu H. P.
Published: August 2014

Previous experimental work has shown that a phase transition in C60 multifragmentation induced by nanosecond laser occurs at almost constant temperature covering a wide range of laser fluency. Here the relative yields of ionic fragments (IFs) Cn+ (n = 1–20) resulting from the multifragmentation are measured within the phase transition region. By excluding two small IFs and magic IFs due to their abnormal behavior, the data for residual IFs are used to estimate the size distributions of primary intermediate-mass IFs in the multifragmentation regime. The distributions are found to obey power laws n−τ. Furthermore, the exponent τ values have sensitive dependence on lower laser fluency and converge to a constant of about 2.4 ± 0.2 for larger fluencies. These observations are in good agreement with an explanation based on the Fisher droplet model, offering the tantalizing possibility of a liquid-to-gas phase transition in C60 systems.
Domain switching by electron beam irradiation of Z+-polar surface in Mg-doped lithium niobate
Authors: Shur V. Ya. , Chezganov D. S. , Smirnov M. M. , Alikin D. O. , Neradovskiy M. M. , Kuznetsov D. K.
Published: August 2014

The appearance of the static domains with depth above 200 μm in the bulk of MgO-doped lithium niobate single crystals as a result of focused electron beam irradiation of Z+-polar surface was demonstrated. The created domain patterns were visualized by high-resolution methods including piezoresponse force microscopy, scanning electron microscopy, and confocal Raman microscopy. The main stages of the domain structure formation were revealed and explained in terms of the original model.
Application of one-dimensional stagnation solutions to three-dimensional simulation of compact wire array in absence of radiation
Authors: Yu Edmund P. , Velikovich A. L. , Maron Y.
Published: August 2014

We investigate the stagnation phase of a three-dimensional (3D), magnetohydrodynamic simulation of a compact, tungsten wire-array Z pinch, under the simplifying assumption of negligible radiative loss. In particular, we address the ability of one-dimensional (1D) analytic theory to describe the time evolution of spatially averaged plasma properties from 3D simulation. The complex fluid flows exhibited in the stagnated plasma are beyond the scope of 1D theory and result in centrifugal force as well as enhanced thermal transport. Despite these complications, a 1D homogeneous (i.e., shockless) stagnation solution can capture the increase of on-axis density and pressure during the initial formation of stagnated plasma. Later, when the stagnated plasma expands outward into the imploding plasma, a 1D shock solution describes the decrease of on-axis density and pressure, as well as the growth of the shock accretion region.
Scaling up the shape: A novel growth pattern of gallium clusters
Authors: Kaware Vaibhav , Joshi Kavita
Published: August 2014

Putative global minima for \documentclass[12pt]{minimal}\begin{document}${\rm Ga}_{N}^+$\end{document} Ga N+ clusters with size “N” ranging from 49 to 70 are found by employing the Kohn-Sham formulation of the density functional theory, and their evolution is described and discussed in detail. We have discovered a unique growth pattern in these clusters, all of which are hollow core-shell structures. They evolve with size from one spherical core-shell to the next spherical core-shell structure mediated by prolate geometries, with an increase in overall diameter of the core, as well as the shell, without putting on new layers of atoms. We also present a complete picture of bonding in gallium clusters by critically analyzing the molecular orbitals, the electron localization function, and Bader charges. Bonding in these clusters is a mixture of metallic and covalent type that leans towards covalency, accompanied by marginal charge transfer from the surface to the core. Most molecular orbitals of Ga clusters are non-jellium type. Covalency of bonding is supported by a wide localization window of electron localization function, and joining of its basins along the bonds.
Exceptional orthogonal polynomials and generalized Schur polynomials
Authors: Grandati Yves
Published: August 2014

We show that the exceptional orthogonal polynomials can be viewed as confluent limits of the generalized Schur polynomials introduced by Sergeev and Veselov.
A strategy to stabilise the local structure of Ti4+ and Zn2+ species against aging in TiO2/aluminium-doped ZnO bi-layers for applications in hybrid solar cells
Authors: Pellegrino Giovanna , La Magna Antonino , Condorelli Guglielmo G. , Bongiorno Corrado , Mocuta Cristian , Smecca Emanuele , Alberti Alessandra
Published: August 2014

We explore a strategy to counteract aging issues in TiO2/aluminium-doped ZnO bi-layers used in hybrid solar cells photo-anodes, mainly related to Zn diffusion in the TiO2 matrix. Different Ti4+ and Zn2+ local structures within the anatase grains and along the film thickness were found as a function of post-deposition annealing treatments in the range between 200 °C and 500 °C by synchrotron radiation extended x-ray absorption fine structure analyses. In particular, in the 500 °C-treated sample, diffusion of zinc species along the TiO2 grain-boundaries has been observed with aging (3 years). In contrast, a mild thermal budget at 200 °C favours a proper atomic arrangement of the zinc-containing anatase lattice which reduces Zn diffusion, thus guaranteeing a good stability with aging.
Observed damage during Argon gas cluster depth profiles of compound semiconductors
Authors: Barlow Anders J. , Portoles Jose F. , Cumpson Peter J.
Published: August 2014

Argon Gas Cluster Ion Beam (GCIB) sources have become very popular in XPS and SIMS in recent years, due to the minimal chemical damage they introduce in the depth-profiling of polymer and other organic materials. These GCIB sources are therefore particularly useful for depth-profiling polymer and organic materials, but also (though more slowly) the surfaces of inorganic materials such as semiconductors, due to the lower roughness expected in cluster ion sputtering compared to that introduced by monatomic ions. We have examined experimentally a set of five compound semiconductors, cadmium telluride (CdTe), gallium arsenide (GaAs), gallium phosphide (GaP), indium arsenide (InAs), and zinc selenide (ZnSe) and a high-κ dielectric material, hafnium oxide (HfO), in their response to argon cluster profiling. An experimentally determined HfO etch rate of 0.025 nm/min (3.95 × 10−2 amu/atom in ion) for 6 keV Ar gas clusters is used in the depth scale conversion for the profiles of the semiconductor materials. The assumption has been that, since the damage introduced into polymer materials is low, even though sputter yields are high, then there is little likelihood of damaging inorganic materials at all with cluster ions. This seems true in most cases; however, in this work, we report for the first time that this damage can in fact be very significant in the case of InAs, causing the formation of metallic indium that is readily visible even to the naked eye.
Radiative cooling of two-component wire-array Z-pinch plasma
Authors: Ivanov V. V. , Mancini R. C. , Papp D. , Hakel P. , Durmaz T. , Florido R.
Published: August 2014

Wire-array two-component Z-pinch plasmas containing Al and other elements were studied experimentally and the observations interpreted with the help of theoretical modeling. Special attention was given to achieving reproducible implosions. Cascading implosions in star wire arrays mix components during the implosion phase and implosion dynamics were not affected by changes in concentration. A reduction in Al K-shell radiation and an increase in soft x-ray radiation emission were observed in Al-W plasma with 84% concentration of Al ions compared to only-Al plasma. Plasma with 84% of Al ions has radiative properties like those of W Z-pinches. The analysis of Al K-shell x-ray spectra with a collisional-radiative atomic kinetics model shows a drop of the electron temperature from 400 eV in pure Al plasma to below 300 eV in the Al-W mix. Al-Au Z-pinches present radiation features similar to Al-W plasma. This is indicative of a similar plasma cooling effect due to the presence of a high-Z element.
Cathodic peeling damage of Cu6Sn5 phase in Cu/SnAg3.0Cu0.5/Cu bridge interconnections under current stressing
Authors: Zhang Z. H. , Cao H. J. , Li M. Y. , Wang Y. , Liu Z. Q.
Published: August 2014

The cathodic interfacial damage behavior that has been attributed to electromigration is serious but has often been confused with thermomigration damage in solder interconnections. In this paper, after the effects of the non-uniform temperature distribution of Cu/SnAg3.0Cu0.5/Cu bridge joints are decoupled from the effects of the current stress, the microstructural evolution of the cathodic Cu6Sn5 phase is investigated under an average current density of 7.12 × 107 A·m−2 for 0–350 h. The results show that the interfacial Cu6Sn5 peels rather than dissolving completely at the cathode, because of both adhesion degradation at the Cu6Sn5/Cu interface and sustained cathodic stresses. This unrecorded peeling behavior will contribute to the rapid formation of interfacial voids and will thus dramatically increase the risk of interfacial failure. Fortunately, by restricting the intergranular diffusion and enhancing the bond strengths between adjacent Cu6Sn5 grains, an aging pre-treatment of the solder joints is found to be an effective way to slow down the Cu6Sn5 peeling process and achieve robust solder interconnections.
Circular dichroism in a three-dimensional semiconductor chiral photonic crystal
Authors: Takahashi S. , Tajiri T. , Ota Y. , Tatebayashi J. , Iwamoto S. , Arakawa Y.
Published: August 2014

Circular dichroism covering the telecommunication band is experimentally demonstrated in a semiconductor-based three-dimensional chiral photonic crystal (PhC). We design a rotationally stacked woodpile PhC structure where neighboring layers are rotated by 60° and three layers construct a single helical unit. The mirror-asymmetric PhC made from GaAs with sub-micron periodicity is fabricated by a micro-manipulation technique. Due to the large contrast of refractive indices between GaAs and air, the experimentally obtained circular dichroism extends over a wide wavelength range, with the transmittance of right-handed circularly polarized incident light being 85% and that of left-handed light being 15% at a wavelength of 1.3 μm. The obtained results show good agreement with numerical simulations.
Effects of ions on the diffusion coefficient of water in carbon nanotubes
Authors: Gao Xiang , Zhao Tianshou , Li Zhigang
Published: August 2014

In this work, we investigate the ion effects on the diffusion of water in carbon nanotubes through molecular dynamics simulations. The diffusion coefficient of water molecules Dw in the presence of cations (Na+ and K+) and anions (F−, Cl−, and Br−) are calculated by changing the ion concentration. The dependence of Dw on the ion concentration is found highly nonlinear and distinct for different ions. For positively charged systems, as the ion concentration is varied, Dw assumes a maximum under the competition between the number and orientation changes of free OH bonds and the effects of ionic hydration. For negatively charged systems, however, Dw decreases monotonously with increasing ion concentration for F−. For Cl− and Br−, Dw reaches the minima at certain ion concentrations and then gently increases. The different behaviors of Dw in the presence of different anions are caused by the stability change of water hydrogen bonds due to ionic hydration.
Graphene defect formation by extreme ultraviolet generated photoelectrons
Authors: Gao A. , Lee C. J. , Bijkerk F.
Published: August 2014

We have studied the effect of photoelectrons on defect formation in graphene during extreme ultraviolet (EUV) irradiation. Assuming the major role of these low energy electrons, we have mimicked the process by using low energy primary electrons. Graphene is irradiated by an electron beam with energy lower than 80 eV. After e-beam irradiation, it is found that the D peak, I(D), appears in the Raman spectrum, indicating defect formation in graphene. The evolution of I(D)/I(G) follows the amorphization trajectory with increasing irradiation dose, indicating that graphene goes through a transformation from microcrystalline to nanocrystalline and then further to amorphous carbon. Further, irradiation of graphene with increased water partial pressure does not significantly change the Raman spectra, which suggests that, in the extremely low energy range, e-beam induced chemical reactions between residual water and graphene are not the dominant mechanism driving defect formation in graphene. Single layer graphene, partially suspended over holes was irradiated with EUV radiation. By comparing with the Raman results from e-beam irradiation, it is concluded that the photoelectrons, especially those from the valence band, contribute to defect formation in graphene during irradiation.
DNA combing on low-pressure oxygen plasma modified polysilsesquioxane substrates for single-molecule studies
Authors: Sriram K. K. , Chang Chun-Ling , Rajesh Kumar U. , Chou Chia-Fu
Published: August 2014

Molecular combing and flow-induced stretching are the most commonly used methods to immobilize and stretch DNA molecules. While both approaches require functionalization steps for the substrate surface and the molecules, conventionally the former does not take advantage of, as the latter, the versatility of microfluidics regarding robustness, buffer exchange capability, and molecule manipulation using external forces for single molecule studies. Here, we demonstrate a simple one-step combing process involving only low-pressure oxygen (O2) plasma modified polysilsesquioxane (PSQ) polymer layer to facilitate both room temperature microfluidic device bonding and immobilization of stretched single DNA molecules without molecular functionalization step. Atomic force microscopy and Kelvin probe force microscopy experiments revealed a significant increase in surface roughness and surface potential on low-pressure O2 plasma treated PSQ, in contrast to that with high-pressure O2 plasma treatment, which are proposed to be responsible for enabling effective DNA immobilization. We further demonstrate the use of our platform to observe DNA-RNA polymerase complexes and cancer drug cisplatin induced DNA condensation using wide-field fluorescence imaging.
Improvement of bias-stability in amorphous-indium-gallium-zinc-oxide thin-film transistors by using solution-processed Y2O3 passivation
Authors: An Sungjin , Mativenga Mallory , Kim Youngoo , Jang Jin
Published: August 2014

We demonstrate back channel improvement of back-channel-etch amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors by using solution-processed yttrium oxide (Y2O3) passivation. Two different solvents, which are acetonitrile (35%) + ethylene glycol (65%), solvent A and deionized water, solvent B are investigated for the spin-on process of the Y2O3 passivation—performed after patterning source/drain (S/D) Mo electrodes by a conventional HNO3-based wet-etch process. Both solvents yield devices with good performance but those passivated by using solvent B exhibit better light and bias stability. Presence of yttrium at the a-IGZO back interface, where it occupies metal vacancy sites, is confirmed by X-ray photoelectron spectroscopy. The passivation effect of yttrium is more significant when solvent A is used because of the existence of more metal vacancies, given that the alcohol (65% ethylene glycol) in solvent A may dissolve the metal oxide (a-IGZO) through the formation of alkoxides and water.
High-performance chemical-bath deposited CdS thin-film transistors with ZrO2 gate dielectric
Authors: Dondapati Hareesh , Ha Duc , Jenrette Erin , Xiao Bo , Pradhan A. K.
Published: August 2014

We demonstrate high performance chemical bath deposited CdS thin-film transistors (TFTs) using atomic layer deposited ZrO2 based high-k gate dielectric material. Our unique way of isolation of the CdS-based TFTs devices yielded significantly low leakage current as well as remarkable lower operating voltages (<5 V) which is four times smaller than the devices reported on CdS-based TFTs using SiO2 gate dielectric. Upon thermal annealing, the devices demonstrate even higher performance, including μFE exceeding 4 ± 0.2 cm2 V−1S−1, threshold voltage VT of 3.8 V, and Ion-off of 104–105, which hold much promise for applications in future electronic and optical devices.
Investigation on biogas production process from chicken processing industry wastewater using statistical analysis: Modelling and optimization
Authors: Karichappan Thirugnanasambandham , Venkatachalam Sivakumar , Jeganathan Prakash Maran
Published: August 2014

In this present study, biogas production process was investigated using four factors—three level Box-Behnken statistical experimental design under different anaerobic conditions such as pH (4–10), temperature (25–45 °C), alkalinity dose (6%–24%), and time (6–30 days) from chicken processing industry wastewater. The obtained results were analyzed by analysis of variance and the second order polynomial model was developed to study the interactive effect of process conditions on the biogas yield. Optimum conditions for maximizing the biogas yield were determined using derringer's desired function methodology and it was found to be pH of 7, temperature of 40 °C, alkalinity dose of 16%, and time of 21 days. Under optimum conditions, predicted biogas yield was found to be 905 ml with a desirability value of 0.985. Suitability of the predicted optimum conditions was validated using experimental data.
A neutral oxygen-vacancy center in diamond: A plausible qubit candidate and its spintronic and electronic properties
Authors: Zhang Y. G. , Tang Z. , Zhao X. G. , Cheng G. D. , Tu Y. , Cong W. T. , Peng W. , Zhu Z. Q. , Chu J. H.
Published: August 2014

Spintronic and electronic properties of a neutral oxygen-vacancy (O-V) center, an isoelectronic defect similar to the negatively charged nitrogen-vacancy center in diamond, were studied by combining first-principles calculations and a mean-field theory for spin hyperfine interaction. It is elucidated that the neutral O-V center is stable in the p-type diamond and possesses an S = 1 triplet ground state and four spin-conserved excited states with the spin coherence times in an order of second at T = 0 K. The results indicate that the neutral O-V center is another promising candidate for spin coherent manipulation and qubit operation.
Discounting of medicines in Australian community pharmacies
Authors: Thai Loc P. , Vitry Agnes I. , Moss John R.
Published: August 2014

Objective There are many medicines listed on the Australian Pharmaceutical Benefits Scheme (PBS) in which point of sale price is less than the level of the general patient co-payment. In these circumstances, the patient covers the total cost of the medicine from their own pocket with no government subsidy. The aim of the present study was to compare the consumer prices of under general co-payment prescription medicines between banner group pharmacies with open discounting policies and community pharmacies without; and to assess the impact of the April 2012 PBS price disclosure policies on the discounts offered. Methods The consumer prices of 31 under co-payment medicines were collected from banner group pharmacy websites and individual pharmacies both before and after April 2012. PBS maximum prices were obtained from the PBS website. Absolute and relative price differences between PBS and pharmacy groups were calculated. Results Before April 2012, banner group pharmacies provided discounts to patients of around 40% per prescription, whereas other pharmacies provided discounts of around 15%. Total price savings were on average $9 per prescription at banner group pharmacies and $3.50 at other pharmacies. Percentage discounts did not change greatly after April 2012, when price decreases occurred on the PBS. Conclusions Banner group pharmacies with pricing strategies are able to provide greater discounts to patients compared with other pharmacies. Community pharmacies still have the ability to provide substantial discounts after the April 2012 price reductions. What is known about the topic? There is currently little known about the under co-payment medicines market in Australia and the price discounts available to patients. What does this paper add? This research shows that patients who purchase under co-payment medicines are able to save money if they purchase from pharmacies with openly advertised discounting policies. Price reductions related to the implementation of the price disclosure policy had a small effect on the discounts offered by community pharmacies to patients. What are the impacts for practitioners? The effect of discounting on under co-payment medicines to patients may increase their ability to afford essential medicines. Questions remain on whether the effect of discounting on under co-payment medicines may affect the quality of professional services provided to patients by pharmacists.
Free-energy inference from partial work measurements in small systems
Authors: Ribezzi-Crivellari Marco , Ritort Felix
Published: August 2014

Significance

Fluctuation relations (FRs) provide general results about work (or total entropy production) distributions in nonequilibrium systems. However, in many cases the full work is not measurable and only partial work measurements are possible. The latter do not fulfill a FR and cannot be used to extract free-energy differences from irreversible work measurements. We show how FRs can be used to infer the full work distribution from partial work measurements. We illustrate the inference process, using dual-trap optical tweezers where two forces (one per trap) are measured, and we can access both the full and the partial work distributions. We derive a set of results of direct interest to single-molecule scientists and, more generally, to physicists and biophysicists.
Temporal and spatial organization of ESCRT protein recruitment during HIV-1 budding
Authors: Bleck Marina , Itano Michelle S. , Johnson Daniel S. , Thomas V. Kaye , North Alison J. , Bieniasz Paul D. , Simon Sanford M.
Published: August 2014

Significance

HIV-1 infection and the associated disease AIDS are a major cause of human death worldwide with no vaccine or cure available. The assembly of virus particles involves numerous host and viral proteins that are potential therapeutic targets. We used high-resolution microscopy techniques to investigate how the virus hijacks cellular proteins to enable the release of virions from an infected cell. We show with high temporal and spatial resolution that components of the host endosomal sorting complex required for transport (ESCRT) machinery are recruited to the neck of the assembling virus to facilitate scission of the link between the virus and the cell.
Comparative Swimming Performance of Five Catostomus Species and Roundtail Chub
Authors: Underwood Zachary E. , Myrick Christopher A. , Compton Robert I.
Published: August 2014

Abstract.—Decreased habitat connectivity and competition with nonnative species have led to declines of many freshwater fishes. An understanding of swimming performance can aid in the conservation of these fishes; however, acquiring sufficient numbers of rare and threatened species to perform swimming studies can be logistically challenging and ecologically costly. In order to determine whether swimming data for common sucker species may be substituted for that of similar but rare sucker species, we compared the swimming abilities of two rare western catostomids, Bluehead Sucker Catostomus discobolus and Flannelmouth Sucker C. latipinnis, as well as one catostomid with a less well understood status, Mountain Sucker C. platyrhynchus, with those of the common White Sucker C. commersonii and Longnose Sucker C. catostomus. We also examined Roundtail Chub Gila robusta because they are often included in conservation efforts involving Bluehead Sucker and Flannelmouth Sucker. The critical swimming velocities (Ucrit), standardized by body length, of Bluehead Sucker and Longnose Sucker differed significantly from those of White Sucker. However, there was no significant difference between the Ucrit of Mountain Sucker, Flannelmouth Sucker, and White Sucker. During constant acceleration trials, Bluehead Sucker exhibited the greatest swimming ability, reaching a mean maximum velocity of 4.56 ± 1.28 body lengths per second (BL/s; mean ± SD), followed by Mountain Sucker (3.56 ± 0.57 BL/s), White Sucker (3.28 ± 0.90 BL/s), Longnose Sucker (2.97 ± 0.31 BL/s), and Flannelmouth Sucker (2.22 ± 0.42 BL/s). Additionally, key behavioral differences in the swimming behaviors of the fishes studied were observed. We conclude that swimming performance data for common White Sucker should not be used in place of data for rarer species. Comprehensive swimming studies should be conducted on individual sucker species before implementing conservation strategies involving fish passageways or barriers.

Received November 6, 2013; accepted February 28, 2014
Use of an Ecosystem-Based Model to Evaluate Alternative Conservation Strategies for Juvenile Chinook Salmon in a Headwater Stream
Authors: Warren D. R. , Harvey C. J. , McClure M. M. , Sanderson B. L.
Published: August 2014

Declining abundance of Chinook Salmon Oncorhynchus tshawytscha across the Pacific Northwest is an issue of great concern ecologically, culturally, and economically. Growth during the first summer is vitally important for juvenile Chinook Salmon, as it influences not only life history decisions (to smolt or not to smolt) but also subsequent river and ocean survival. Using Ecopath with Ecosim, we developed a food web model for a representative stream in the Salmon River basin, Idaho, to evaluate potential species-specific and food web effects of three management strategies: (1) adding salmon carcasses or carcass analogs to promote primary production and detrital availability that were lost due to declining salmon returns; (2) removal of nonnative Brook Trout Salvelinus fontinalis, which are competitors with and predators on juvenile Chinook Salmon; and (3) stocking hatchery Chinook Salmon into streams to supplement wild production. Overall, juvenile Chinook Salmon responded strongly to increases in basal resources. Removal of Brook Trout had little effect on potential production for juvenile Chinook Salmon, but the responses of sculpins Cottus spp. were strong, primarily due to the sculpins’ high degree of dietary overlap with and predation by Brook Trout. Supplementation with hatchery-origin juveniles depressed the production of wild juvenile Chinook Salmon, especially at the densities commonly applied to streams in this region. Our results suggest that efforts to enhance basal resources are likely to be the most effective in promoting the production of juvenile Chinook Salmon and nearly all food web groups considered in our model system. Removal of nonnative Brook Trout is unlikely to substantially affect salmon but could have a disproportionately large effect on nongame species, which are generally overlooked in single-species management approaches.

Received October 2, 2013; accepted March 24, 2014
Otolith Daily Increment Deposition in Age-0 Smallmouth Bass Reared in Constant and Fluctuating Water Temperatures
Authors: Hill Angela A. , Bestgen Kevin R.
Published: August 2014

We reared embryos and larvae of Smallmouth Bass Micropterus dolomieu in constant and diel fluctuating water temperatures (mean of 20°C) to clarify when otolith first daily increments were deposited and the periodicity of increment formation. Unlike the results of previously published studies, we found that first-increment formation began at hatching rather than 7–11 d later at swim-up. We confirmed that increment deposition was daily and extended the daily increment validation period from 21 d to 30 d posthatch. Accurate and precise age estimation was possible for Smallmouth Bass reared in both constant and fluctuating temperature environments, as age estimates rarely varied more than 1 d from true age. We also found consistent estimated ages using either left or right sagittae and showed relationships for Smallmouth Bass total length as a function of age, and otolith diameter as a function of total length. Otolith daily increment counts allow accurate and precise estimates of Smallmouth Bass age, which enables determination of hatch date, timing of spawning, and growth rate. These findings may assist with the management of this species, as well as provide information that can be used to disadvantage reproductive success of invasive Smallmouth Bass.

Received October 31, 2013; accepted March 28, 2014
Effects of Seawalls and Piers on Fish Assemblages and Juvenile Salmon Feeding Behavior
Authors: Munsch Stuart H. , Cordell Jeffery R. , Toft Jason D. , Morgan Erin E.
Published: August 2014

Shoreline modifications, such as seawall armoring and piers, are ubiquitous along developed waterfronts worldwide, and recent research suggests that their ecological effects are primarily negative. We utilized snorkel surveys to quantify the effects of seawalls and piers on fish in nearshore habitats of an urbanized estuary in Puget Sound, Washington. We observed 17 species of fish and 4 species of crab during April–August 2012 at sites modified by seawalls and piers and at reference beach sites with minimal anthropogenic structures. Species assemblages at modified sites were significantly different from those at reference beaches. At modified sites, fish distribution and assemblage structure varied with proximity to the shade cast by piers; overall fish abundances were reduced under piers, and the greatest abundances were observed at high tides in areas directly adjacent to piers. Juvenile Pacific salmon Oncorhynchus spp. were the dominant fish species, and piers reduced their presence and feeding, indicating that areas under piers provide less-valuable habitat to salmon species. Piers may interrupt movements of juvenile salmon when they use shallow waters along shorelines to migrate from freshwater to marine habitats, as juvenile salmon tend to avoid shade under piers, especially at high tides. Our results show that shoreline modifications can alter species assemblage structure, thus potentially creating novel combinations and abundances of species, and can reduce habitat function for species that utilize these and similar habitats elsewhere.

Received December 27, 2013; accepted March 27, 2014
Genetic Diversity and Population Structure of Spring Chinook Salmon from the Upper Willamette River, Oregon
Authors: Johnson Marc A. , Friesen Thomas A.
Published: August 2014

Effective management of Pacific salmon requires an accurate understanding of both population genetic diversity and structure. Spring Chinook Salmon Oncorhynchus tshawytscha from the upper Willamette River (UWR), Oregon, are listed as threatened under the U.S. Endangered Species Act, and although this evolutionarily significant unit is recognized to be distinct from other Columbia River stocks, genetic relationships among its constituent hatchery and wild populations remain obscure. We used genotypic data from 13 microsatellite loci to test whether hatchery populations of UWR spring Chinook Salmon are most similar to wild populations within the same subbasin, or whether hatchery populations from different subbasins are more similar to each other than to local wild populations. We also tested for differences between the genetic diversities of hatchery and wild populations, as measured through heterozygosity and allelic richness. Our results suggest that populations are weakly structured among subbasins and, in all cases, hatchery populations are genetically most similar to local wild populations. We also found heterozygosity to be higher (P = 0.009) in hatchery populations (median, 81.5%) than in wild populations (median, 75.2%), but observed no significant difference with respect to allelic richness (P = 0.406). We conclude that hatchery-origin UWR spring Chinook Salmon represent genetically appropriate founder populations for ongoing reintroduction programs and recommend that the conservation and recovery of this stock proceed through management actions developed specifically for each subbasin. We further recommend that current restrictions on hatchery stock transfers among UWR subbasins be continued to preserve extant population genetic structure.

Received January 8, 2014; accepted April 29, 2014
Long-Term Population Response of Triploid Grass Carp Stocked in Piedmont and Coastal Plain Reservoirs to Control Hydrilla
Authors: Kirk James P. , Manuel Kenneth L. , Lamprecht Scott D.
Published: August 2014

The triploid Grass Carp Ctenopharyngodon idella has been used to control hydrilla Hydrilla verticillata infestations in southern U.S. reservoirs for several decades. After eliminating hydrilla in the water column, Grass Carp must be maintained in sufficient densities to control hydrilla regrowth from the tuber banks in the hydrosoil. We monitored the long-term response of triploid Grass Carp populations that had eliminated hydrilla within the water column in two Piedmont (Lake Norman and Mountain Island Lake, North Carolina) and two Coastal Plain reservoirs (the Santee Cooper system comprising Lakes Marion and Moultrie, as well as the connecting canal in South Carolina). Triploid Grass Carp stocked in Lake Norman and Mountain Island Lake exhibited both slow growth and erratic, but potentially high, mortality. Due to erratic survival in the two Piedmont reservoirs, we could not estimate mortality using a catch curve. Fish stocked into the Santee Cooper system not only grew larger and faster, they also persisted (i.e., significant numbers of age-16–21 fish were collected during sampling in 2011). We hypothesize that Piedmont reservoirs without hydrilla in the water column and with little naturally occurring aquatic vegetation have a very low carrying capacity for triploid Grass Carp. Consistent, long-term survival of triploid Grass Carp in the Santee Cooper system may be due to available food provided by hydrilla regrowth in the water column, floating vegetation, and less-palatable, native, submersed vegetation. Hydrilla management in systems with residual plant food could involve estimating an average mortality rate and maintaining enough fish (i.e., about one fish per four hectares of surface area) to control hydrilla regrowth. In Piedmont reservoirs, possible management alternatives could include maintenance stockings based upon (1) yearling stocking rates that were successful in the past, (2) stockings determined from indirect measures of mortality such as from von Bertalanffy growth equation parameters, or (3) stockings derived from measures or indices of abundance such as counts conducted at night by bowfishers.

Received January 28, 2014; accepted April 20, 2014