bluuebunny/crossref_metadata_2025 huggingface dataset:
Global vs local energy dissipation: The energy cycle of the turbulent von Kármán flow
Authors: Kuzzay Denis , Faranda Davide , Dubrulle Bérengère
Published: July 2015

In this paper, we investigate the relations between global and local energy transfers in a turbulent von Kármán flow. The goal is to understand how and where energy is dissipated in such a flow and to reconstruct the energy cycle in an experimental device where local as well as global quantities can be measured. In order to do so, we use particle image velocimetry (PIV) measurements and we model the Reynolds stress tensor to take subgrid scales into account. This procedure involves a free parameter that is calibrated using angular momentum balance. We then estimate the local and global mean injected and dissipated powers for several types of impellers, for various Reynolds numbers, and for various flow topologies. These PIV estimates are then compared with direct injected power estimates provided by torque measurements at the impellers. The agreement between PIV estimates and direct measurements depends on the flow topology. In symmetric situations, we are able to capture up to 90% of the actual global energy dissipation rate. However, our results become increasingly inaccurate as the shear layer responsible for most of the dissipation approaches one of the impellers and cannot be resolved by our PIV setup. Finally, we show that a very good agreement between PIV estimates and direct measurements is obtained using a new method based on the work of Duchon and Robert [“Inertial energy dissipation for weak solutions of incompressible Euler and Navier-Stokes equations,” Nonlinearity 13, 249–225 (2000)] which generalizes the Kármán-Howarth equation to nonisotropic, nonhomogeneous flows. This method provides parameter-free estimates of the energy dissipation rate as long as the smallest resolved scale lies in the inertial range. These results are used to evidence a well-defined stationary energy cycle within the flow in which most of the energy is injected at the top and bottom impellers and dissipated within the shear layer. The influence of the mean flow geometry and the Reynolds number on this energy cycle is studied for a wide range of parameters.
Structural exploration and Förster theory modeling for the interpretation of gas-phase FRET measurements: Chromophore-grafted amyloid-β peptides
Authors: Kulesza Alexander , Daly Steven , MacAleese Luke , Antoine Rodolphe , Dugourd Philippe
Published: July 2015

The distance-dependence of excitation energy transfer, e.g., being described by Förster theory (Förster resonance energy transfer (FRET)), allows the use of optical techniques for the direct observation of structural properties. Recently, this technique has been successfully applied in the gas phase. The detailed interpretation of the experimental FRET results, however, relies on the comparison with structural modeling. We therefore present a complete first-principles modeling approach that explores the gas-phase structure of chromophore-grafted peptides and achieves accurate predictions of FRET efficiencies. We apply the approach to amyloid-β 12-28 fragments, known to be involved in amyloid plaque formation connected to Alzheimer’s disease. We sample structures of the peptides that are grafted with 5-carboxyrhodamine 575 (Rh575) and QSY-7 chromophores by means of replica-exchange molecular dynamics simulations upon an Amber-type forcefield parametrization as a function of the charge state. The generated ensembles provide chromophore-distance and -orientation distributions which are used with the spectral parameters of the Rh575/QSY-7 chromophores to model FRET-efficiencies for the systems. The theoretical values agree with the experimental average “action”-FRET efficiencies and motivate to use the herein reported parametrization, sampling, and FRET-modeling technique in future studies on the structural properties and aggregation-behavior of related systems.
A magnetocaloric effect arising from a ferromagnetic transition in the martensitic state in Heusler alloy of Ni50Mn36Sb8Ga6
Authors: Tian Fanghua , Zeng Yuyang , Xu Minwei , Yang Sen , Lu Tao , Wang Jieqiong , Chang Tieyan , Adil Murtaza , Zhang Yin , Zhou Chao , Song Xiaoping
Published: July 2015

We report a magnetocaloric effect with nearly zero thermal hysteresis in Heusler alloy of Ni50Mn36Sb8Ga6 around room temperature due to a ferromagnetic transition in martensitic state (FTMS). The refrigerant capacity value of this ferromagnetic transition in the vicinity of onset temperature TCM can arrive at 163.8 J/kg, much higher than that of first-order magnetically martensitic transition in the same alloy. Such a magnetocaloric effect in FTMS is attributed to a second-order (or a weak first-order) transition from an antiferromagnetic phase with modulated 7 M orthorhombic structure to a ferromagnetic phase with modulated 4O orthorhombic structure.
Generalized graph states based on Hadamard matrices
Authors: Cui Shawn X. , Yu Nengkun , Zeng Bei
Published: July 2015

Graph states are widely used in quantum information theory, including entanglement theory, quantum error correction, and one-way quantum computing. Graph states have a nice structure related to a certain graph, which is given by either a stabilizer group or an encoding circuit, both can be directly given by the graph. To generalize graph states, whose stabilizer groups are abelian subgroups of the Pauli group, one approach taken is to study non-abelian stabilizers. In this work, we propose to generalize graph states based on the encoding circuit, which is completely determined by the graph and a Hadamard matrix. We study the entanglement structures of these generalized graph states and show that they are all maximally mixed locally. We also explore the relationship between the equivalence of Hadamard matrices and local equivalence of the corresponding generalized graph states. This leads to a natural generalization of the Pauli (X, Z) pairs, which characterizes the local symmetries of these generalized graph states. Our approach is also naturally generalized to construct graph quantum codes which are beyond stabilizer codes.
Proton tunneling in low dimensional cesium silicate LDS-1
Authors: Matsui Hiroshi , Iwamoto Kei , Mochizuki Dai , Osada Shimon , Asakura Yusuke , Kuroda Kazuyuki
Published: July 2015

In low dimensional cesium silicate LDS-1 (monoclinic phase of CsHSi2O5), anomalous infrared absorption bands observed at 93, 155, 1210, and 1220 cm−1 are assigned to the vibrational mode of protons, which contribute to the strong hydrogen bonding between terminal oxygen atoms of silicate chain (O–O distance = 2.45 Å). The integrated absorbance (oscillator strength) for those modes is drastically enhanced at low temperatures. The analysis of integrated absorbance employing two different anharmonic double-minimum potentials makes clear that proton tunneling through the potential barrier yields an energy splitting of the ground state. The absorption bands at 93 and 155 cm−1, which correspond to the different vibrational modes of protons, are attributed to the optical transition between the splitting levels (excitation from the ground state (n = 0) to the first excited state (n = 1)). Moreover, the absorption bands at 1210 and 1220 cm−1 are identified as the optical transition from the ground state (n = 0) to the third excited state (n = 3). Weak Coulomb interactions in between the adjacent protons generate two types of vibrational modes: symmetric mode (93 and 1210 cm−1) and asymmetric mode (155 and 1220 cm−1). The broad absorption at 100–600 cm−1 reveals an emergence of collective mode due to the vibration of silicate chain coupled not only with the local oscillation of Cs+ but also with the proton oscillation relevant to the second excited state (n = 2).
Growth and spin-wave properties of thin Y3Fe5O12 films on Si substrates
Authors: Stognij A. I. , Lutsev L. V. , Bursian V. E. , Novitskii N. N.
Published: July 2015

We describe synthesis of submicron Y3Fe5O12 (YIG) films sputtered on Si substrates and present results of the investigation of ferromagnetic resonance (FMR) and spin waves in YIG/SiO2/Si structures. It is found that decrease of the annealing time leads to essential reduction of the FMR linewidth ΔH and, consequently, to reduction of relaxation losses of spin waves. Spin-wave propagation in in-plane magnetized YIG/SiO2/Si structures is studied. We observe the asymmetry of amplitude-frequency characteristics of the Damon-Eshbach spin waves caused by different localizations of spin waves at the free YIG surface and at the YIG/SiO2 interface. Growth of the generating microwave power leads to spin-wave instability and changes amplitude-frequency characteristics of spin waves.
Trap modulated photoresponse of InGaN/Si isotype heterojunction at zero-bias
Authors: Chandan Greeshma , Mukundan Shruti , Mohan Lokesh , Roul Basanta , Krupanidhi S. B.
Published: July 2015

n-n isotype heterojunction of InGaN and bare Si (111) was formed by plasma assisted molecular beam epitaxy without nitridation steps or buffer layers. High resolution X-ray diffraction studies were carried out to confirm the formation of epilayers on Si (111). X-ray rocking curves revealed the presence of large number of edge threading dislocations at the interface. Room temperature photoluminescence studies were carried out to confirm the bandgap and the presence of defects. Temperature dependent I-V measurements of Al/InGaN/Si (111)/Al taken in dark confirm the rectifying nature of the device. I-V characteristics under UV illumination, showed modest rectification and was operated at zero bias making it a self-powered device. A band diagram of the heterojunction is proposed to understand the transport mechanism for self-powered functioning of the device.
Development of an enhanced surface plasmon resonance sensor substrate by investigating a periodic nanohole array configuration
Authors: Yokoyama K. , Oishi M. , Oshima M.
Published: July 2015

The sensor system utilizing a surface plasmon resonance (SPR) with nanoparticles and nanostructures measures a peak wavelength shift. In order to enhance the measurement accuracy, it is important to acquire the higher and sharper peak wavelength so as to identify accurately the position of the peak wavelength. We developed an enhanced SPR sensor substrate by investigating the configuration of a periodic nanohole array. We simulated the effects of the configuration parameters. The simulation results revealed that the proposed sensor substrate achieved the higher and sharper peak wavelength by strengthening the SPR intensity as the number of holes per unit structure was increased from one to three, and with allocation of the unit structure in a triangular lattice so as to have one rotational symmetry. We also verified our simulation results experimentally by fabricating nanohole array sensor substrates.
Direct current-dielectrophoresis assisted microscale machining of metal by femtosecond pulsed laser
Authors: Park ChangKyoo , Farson Dave F.
Published: July 2015

Accumulation of ablation debris particles interferes with femtosecond laser micromachining of high-aspect ratio grooves in metal. Debris removal from such grooves by an air or inert gas jet requires that the gas jet axis be aligned with the groove. This requirement constrains the motion system design and programming as well as the gas nozzle design for cutting of arbitrary shapes. Gas jet debris removal is also not feasible in vacuum environments. In this study, a novel technique based on DC-dielectrophoresis (DEP) for removing debris from the cut groove was investigated. Femtosecond laser ablation of linear and circular grooves from thick sections of aluminum was performed with no debris removal and with debris removal by air jet or DC-DEP force. Ablation depth and precision were compared for the three experimental conditions. Debris removal by DC-DEP force resulted in the most accurate, consistent, and orientation-independent machining of high-aspect ratio grooves. Moreover, larger electric fields exerted stronger DC-DEP force on debris particles and resulted in better ablation precision and machining rate.
Preliminary design and optimization of a G-band extended interaction oscillator based on a pseudospark-sourced electron beam
Authors: Yin Y. , He W. , Zhang L. , Yin H. , Cross A. W.
Published: July 2015

The design and simulation of a G-band extended interaction oscillator (EIO) driven by a pseudospark-sourced electron beam is presented. The characteristic of the EIO and the pseudospark-based electron beam were studied to enhance the performance of the newly proposed device. The beam-wave interaction of the EIO can be optimized by choosing a suitable pseudospark discharging voltage and by widening the operating voltage region of the EIO circuit. Simulation results show that a peak power of over 240 W can be achieved at G-band using a pseudospark discharge voltage of 41 kV.
Cut-cell method based large-eddy simulation of tip-leakage flow
Authors: Pogorelov Alexej , Meinke Matthias , Schröder Wolfgang
Published: July 2015

The turbulent low Mach number flow through an axial fan at a Reynolds number of 9.36 × 105 based on the outer casing diameter is investigated by large-eddy simulation. A finite-volume flow solver in an unstructured hierarchical Cartesian setup for the compressible Navier-Stokes equations is used. To account for sharp edges, a fully conservative cut-cell approach is applied. A newly developed rotational periodic boundary condition for Cartesian meshes is introduced such that the simulations are performed just for a 72° segment, i.e., the flow field over one out of five axial blades is resolved. The focus of this numerical analysis is on the development of the vortical flow structures in the tip-gap region. A detailed grid convergence study is performed on four computational grids with 50 × 106, 250 × 106, 1 × 109, and 1.6 × 109 cells. Results of the instantaneous and the mean fan flow field are thoroughly analyzed based on the solution with 1 × 109 cells. High levels of turbulent kinetic energy and pressure fluctuations are generated by a tip-gap vortex upstream of the blade, the separating vortices inside the tip gap, and a counter-rotating vortex on the outer casing wall. An intermittent interaction of the turbulent wake, generated by the tip-gap vortex, with the downstream blade, leads to a cyclic transition with high pressure fluctuations on the suction side of the blade and a decay of the tip-gap vortex. The disturbance of the tip-gap vortex results in an unsteady behavior of the turbulent wake causing the intermittent interaction. For this interaction and the cyclic transition, two dominant frequencies are identified which perfectly match with the characteristic frequencies in the experimental sound power level and therefore explain their physical origin.
Coalescence of silver clusters by immersion in diluted HF solution
Authors: Milazzo R. G. , Mio A. M. , D’Arrigo G. , Grimaldi M. G. , Spinella C. , Rimini E.
Published: July 2015

The galvanic displacement deposition of silver on H-terminated Si (100) in the time scale of seconds is instantaneous and characterized by a cluster density of 1011-1012 cm−2. The amount of deposited Ag follows a t1/2 dependence in agreement with a Cottrell diffusion limited mechanism. At the same time, during the deposition, the cluster density reduces by a factor 5. This behavior is in contrast with the assumption of immobile clusters. We show in the present work that coalescence and aggregation occur also in the samples immersed in the diluted hydrofluoric acid (HF) solution without the presence of Ag+. Clusters agglomerate according to a process of dynamic coalescence, typical of colloids, followed by atomic redistribution at the contact regions with the generation of multiple internal twins and stacking-faults. The normalized size distributions in terms of r/rmean follow also the prediction of the Smoluchowski ripening mechanism. No variation of the cluster density occurs for samples immersed in pure H2O solution. The different behavior might be associated to the strong attraction of clusters to oxide-terminated Si surface in presence of water. The silver clusters are instead weakly bound to hydrophobic H-terminated Si in presence of HF. HF causes then the detachment of clusters and a random movement on the silicon surface with mobility of about 10−13 cm2/s. Attractive interaction (probably van der Waals) among particles promotes coarsening.
A new form of Ca3P2 with a ring of Dirac nodes
Authors: Xie Lilia S. , Schoop Leslie M. , Seibel Elizabeth M. , Gibson Quinn D. , Xie Weiwei , Cava Robert J.
Published: July 2015

We report the synthesis and crystal structure of a new high-temperature form of Ca3P2. The crystal structure was determined through Rietveld refinements of synchrotron powder x-ray diffraction data. This form of Ca3P2 has a crystal structure of the hexagonal Mn5Si3 type, with a Ca ion deficiency compared to the ideal 5:3 stoichiometry. This yields a stable, charge-balanced compound of Ca2+ and P3−. We also report the observation of a secondary hydride phase, Ca5P3H, which again is a charge-balanced compound. The calculated band structure of Ca3P2 indicates that it is a three-dimensional Dirac semimetal with a highly unusual ring of Dirac nodes at the Fermi level. The Dirac states are protected against gap opening by a mirror plane in a manner analogous to what is seen for graphene.
Studies on the microwave permittivity and electromagnetic wave absorption properties of Fe-based nano-composite flakes in different sizes
Authors: Wu Yanhui , Han Mangui , Liu Tao , Deng Longjiang
Published: July 2015

The effective permittivity of composites containing Fe-Cu-Nb-Si-B nanocrystalline micro flakes has been studied within 0.5–10 GHz. Obvious differences in microwave permittivity have been observed for composites consisting of large flakes (size range: 23–111 μm, average thickness: 4.5 μm) and small flakes (size range: 3–21 μm, average thickness: 1.3 μm). Both the real part and imaginary part of permittivity of large flake composite are much larger than these small one in a given frequency. And faster decrease of permittivity with the increasing frequency can be observed for large flake composite than that of small one. These differences in permittivity spectra of different flakes have been explained from the perspective of interfacial polarization and ac conductivity. The assumption that more extensive ohmic contact interface between large flakes and matrix has been validated by the fittings and the calculated percolation threshold. Meanwhile, the permeability spectra of both composites also have been studied by Lorentzian dispersion law. The broadened spectra can be attributed to the distribution of magnetic anisotropy fields of two kinds of ferromagnetic phases in the particles. Finally, the composite containing the small flakes exhibits better electromagnetic wave absorption properties.
Anisotropic magnetic-field-induced phase transition in MnAs nanoribbons
Authors: Fernandez Baldis F. , Sirena Martín , Steren Laura B. , Etgens V. H. , Eddrief M. , Ulysse C. , Faini G.
Published: July 2015

MnAs thin films present a phase coexistence of regularly arranged ferromagnetic (α) and paramagnetic (β) stripes below the Curie temperature when grown onto GaAs(100) substrates. In this letter, we report the observation of a magneto-structural phase transition induced by magnetic field on MnAs nanoribbons below the Curie temperature. A transformation of high-resistance paramagnetic regions into low-resistance ferromagnetic ones is observed above temperature-dependent critical magnetic fields. The phenomenon is hysteretic, highly anisotropic, and size dependent and could be the origin of the high magneto-resistance effect observed at temperatures close to room temperature in these systems.
Fast terahertz imaging using a quantum cascade amplifier
Authors: Ren Yuan , Wallis Robert , Jessop David Stephen , Degl'Innocenti Riccardo , Klimont Adam , Beere Harvey E. , Ritchie David A.
Published: July 2015

A terahertz (THz) imaging scheme based on the effect of self-mixing in a 2.9 THz quantum cascade (QC) amplifier has been demonstrated. By coupling an antireflective-coated silicon lens to the facet of a QC laser, with no external optical feedback, the laser mirror losses are enhanced to fully suppress lasing action, creating a THz QC amplifier. The addition of reflection from an external target to the amplifier creates enough optical feedback to initiate lasing action and the resulting emission enhances photon-assisted transport, which in turn reduces the voltage across the device. At the peak gain point, the maximum photon density coupled back leads to a prominent self-mixing effect in the QC amplifier, leading to a high sensitivity, with a signal to noise ratio up to 55 dB, along with a fast data acquisition speed of 20 000 points per second.
A magnetic atomic laminate from thin film synthesis: (Mo0.5Mn0.5)2GaC
Authors: Meshkian R. , Ingason A. S. , Arnalds U. B. , Magnus F. , Lu J. , Rosen J.
Published: July 2015

We present synthesis and characterization of a new magnetic atomic laminate: (Mo0.5Mn0.5)2GaC. High quality crystalline films were synthesized on MgO(111) substrates at a temperature of ∼530 °C. The films display a magnetic response, evaluated by vibrating sample magnetometry, in a temperature range 3-300 K and in a field up to 5 T. The response ranges from ferromagnetic to paramagnetic with change in temperature, with an acquired 5T-moment and remanent moment at 3 K of 0.66 and 0.35 μB per metal atom (Mo and Mn), respectively. The remanent moment and the coercive field (0.06 T) exceed all values reported to date for the family of magnetic laminates based on so called MAX phases.
Plasmon enhanced broadband optical absorption in ultrathin silicon nanobowl array for photoactive devices applications
Authors: Sun Rui-Nan , Peng Kui-Qing , Hu Bo , Hu Ya , Zhang Fu-Qiang , Lee Shuit-Tong
Published: July 2015

Both photonic and plasmonic nanostructures are key optical components of photoactive devices for light harvesting, enabling solar cells with significant thickness reduction, and light detectors capable of detecting photons with sub-band gap energies. In this work, we study the plasmon enhanced broadband light absorption and electrical properties of silicon nanobowl (SiNB) arrays. The SiNB-metal photonic-plasmonic nanostructure-based devices exhibited superior light-harvesting ability across a wide range of wavelengths up to the infrared regime well below the band edge of Si due to effective optical coupling between the SiNB array and incident sunlight, as well as electric field intensity enhancement around metal nanoparticles due to localized surface plasmon resonance. The photonic-plasmonic nanostructure is expected to result in infrared-light detectors and high-efficiency solar cells by extending light-harvesting to infrared frequencies.
Taming electromagnetic metamaterials for isotropic perfect absorbers
Authors: Anh Doan Tung , Viet Do Thanh , Trang Pham Thi , Thang Nguyen Manh , Quy Ho Quang , Hieu Nguyen Van , Lam Vu Dinh , Tung Nguyen Thanh
Published: July 2015

Conventional metamaterial absorbers, which consist of a dielectric spacer sandwiched between metamaterial resonators and a metallic ground plane, have been inherently anisotropic. In this paper, we present an alternative approach for isotropic perfect absorbers using symmetric metamaterial structures. We show that by systematically manipulating the electrically and magnetically induced losses, one can achieve a desired absorption without breaking the structural homogeneity. Finite integration simulations and standard retrieval method are performed to elaborate on our idea.
The effects of essential oil and condensed tannin on fermentation and methane production under in vitro conditions
Authors: Pinski Brittany , Günal Mevlüt , AbuGhazaleh Amer A.
Published: July 2015

The potential of five different essential oils (EO) and quebracho condensed tannin extract (QCT) as antimethanogenic additives in ruminant feeds were investigated. The first experiment was conducted to screen the effects rosemary oil, sage oil, cinnamon oil (CNO), eucalyptus oil and myrrh oil at 500 mg/L of culture fluid on methane (CH4) production under in vitro conditions. Rumen contents were collected from a cannulated Holstein dairy cow and used for a 24-h batch-culture experiment. Treatments were a control (CON) or CON plus EO at 500 mg/L. Results showed that CNO decreased CH4 production and, therefore, was selected for Experiment 2. The second experiment was designed to test the effects of CNO at three different dose levels on CH4 production and fermentation in 24-h batch-culture experiments. Treatments were CON or CON plus CNO supplemented at 125, 250 and 500 mg/L. Relative to CON, CNO decreased total gas production at the 250 and 500 mg/L doses. All doses of CNO decreased CH4 production. Total volatile fatty acid production was lower in cultures incubated with CNO at the 500 mg/L. Ammonia-N concentration decreased in cultures incubated with CNO at the 500 mg/L. The third experiment was designed to test the effects of QCT on CH4 production and fermentation in 24-h batch cultures. Treatments were CON or CON plus QCT at 25, 50 and 75 g/kg of diet DM. Relative to CON, total volatile fatty acid concentration increased with the 50 g/kg QCT, but was similar to the 25 and 75 g/kg QCT. The proportions of acetate decreased, while the proportions of propionate increased with the 25 g/kg QCT compared with CON. Methane production was not affected in cultures incubated with QCT. Relative to CON, all doses of QCT decreased ammonia-N concentration. In conclusion, results from the present study showed that except for CNO, EO tested in the study had no effects on rumen CH4 production. Addition of CNO to rumen cultures at 125 and 250 mg/L reduced CH4 production without negative effects on rumen fermentation. Quebracho condensed tannin-extract supplementation had no effects on CH4 production and fermentation parameters except for ammonia-N concentration.
Comparison of B-splines and non-linear functions to describe growth patterns and predict mature weight of female beef cattle
Authors: Cano G. , Blanco M. , Casasús I. , Cortés-Lacruz X. , Villalba D.
Published: July 2015

The objective of this study was to compare the ability of Basis spline (B-spline) models and five non-linear functions (Richards, Brody, Von Bertalanffy, Gompertz and Logistic) to describe the growth of females of a beef cattle breed and predict cow mature weight (A). Random regression models that included animal variation within function parameters were fitted using mixed model procedures. Comparisons were made among these functions for goodness of fit, standardised residuals and biological interpretability of the growth curve parameters. The B-spline function showed the best goodness of fit and within non-linear functions, the Richards and Von Bertalanffy functions estimated bodyweight at different periods accurately. The method of fitting the residual variance that provided the best goodness of fit in the model was the constant plus power variance function. The Richards function was found to be the best non-linear function and was compared with the B-spline function to predict mature weight. When the A parameter was estimated using fixed effects, it had a low correlation with the actual mature weight of the cow and the use of this estimate yielded no more gain in predictive accuracy of mature weight than the use of average breed mature weight. When A was estimated using fixed and random effects, it had a moderate correlation with actual mature weight for the B-spline and Richards functions. The use of both types of effects to estimate the maturity index reduced the error compared with the use of average mature weight, especially for the B-spline function, which is recommended as the best function to describe animal growth and predict mature weight.
Management and meteorological factors affect fertility after artificial insemination in Murciano-Granadina goats
Authors: Arrébola Francisco , Palacios Carlos , Gil María-Jesús , Abecia José-Alfonso
Published: July 2015

Over 6 years, 2004 artificial inseminations (AI) were documented from 13 goat farms. We quantified the effect on fertility rate of management factors (farm, year, month, timing and order of insemination, dose of progestagen, prostaglandin, equine chorionic gonadotrophin and prostaglandin doses, age, technician, problems at AI, body condition and buck) and meteorological conditions at AI (mean, maximum and minimum temperatures, mean relative humidity, mean solar radiation, and total rainfall). Meteorological variables were converted to categorical variables to quartiles and deciles. Overall fertility was 56%. Each of the management factors had a significant (P < 0.05) effect on fertility. Non-pregnant goats differed significantly in most of the meteorological variables. Successful inseminations were associated with significantly (P < 0.001) higher mean, maximum and minimum temperatures, and solar radiation, and lower relative humidity, and rainfall, than were failed inseminations. Fertility rates of the highest and lowest deciles were significantly different for each of the meteorological variables. Inseminations performed when meteorological values were in the highest decile of mean (62%), maximum (61%) and minimum temperature (60%), and solar radiation (59%), and the lowest of relative humidity (61%) and rainfall (57%) had a significantly (P < 0.0001) higher proportion of does that became pregnant than when meteorological values were within the opposite decile (47%; 34%; 55%; 46%; 45%, and 43%, respectively). In conclusion, management and meteorological factors affected the success of AI in goats. Although technical factors can be controlled, it remains to be determined whether scheduling the dates of insemination based on forecasted temperatures can improve the success of AI.
Assessing threats from coral and crustose coralline algae disease on the reefs of New Caledonia
Authors: Aeby Greta , Tribollet Aline , Lasne Gregory , Work Thierry
Published: July 2015

The present study reports the results of the first quantitative survey of lesions on coral and crustose coralline algae (CCA) on reefs in the lagoon of New Caledonia. Surveys on inshore and offshore reefs were conducted at 13 sites in 2010, with 12 sites resurveyed in 2013. Thirty coral diseases affecting 15 coral genera were found, with low overall disease prevalence (<1%). This study extends the known distribution of growth anomalies to the coral genera Platygyra and Hydnophora, endolithic hypermycosis to Platygyra, Leptoria and Goniastrea and extends the geographic range of three CCA diseases. We found the first trematode infection in Porites outside of Hawaii. Disease prevalence differed among coral genera, with Porites having more lesions, and Acropora and Montipora fewer lesions, than expected on the basis of field abundance. Inshore reefs had a lower coral-colony density, species diversity and reduced CCA cover than did the offshore reefs. Disease prevalence was significantly higher on inshore reefs in 2013 than in 2010, but did not change on offshore reefs. The potential ecological impact of individual coral diseases was assessed using an integrative-scoring and relative-ranking scheme based on average frequency of occurrence, prevalence and estimated degree of virulence. The top-five ranked diseases were all tissue-loss diseases.
Unravelling the impact of harvesting pressure on canopy-forming macroalgae
Authors: Stagnol Doriane , Michel Renaud , Davoult Dominique
Published: July 2015

Canopy-forming macroalgae create a specific surrounding habitat (the matrix) with their own ecological properties. Previous studies have shown a wide range of responses to canopy removal. Magnitude and strength of the effects of harvesting are thought to be context-dependent, with the macroalgal matrix that can either soften or exacerbate the impact of harvesting. We experimentally examined in situ the effect of harvesting on targeted commercial species, and how these potential impacts might vary in relation to its associated matrix. We found that patterns of recovery following the harvesting disturbance were variable and matrix specific, suggesting that local factors and surrounding habitat characteristics mediated the influence of harvesting. The greatest and longest effects of harvesting were observed for the targeted species that created a dominant and monospecific canopy on their site prior to the disturbance. Another relevant finding was the important natural spatiotemporal variability of macrobenthic assemblages associated with canopy-forming species, which raises concern about the ability to discriminate the natural variability from the disturbance impact. Finally, our results support the need to implement ecosystem-based management, assessing both the habitat conditions and ecological roles of targeted commercial species, in order to insure the sustainability of the resource.
Phytoplankton dynamics in a subtropical tidal creek: influences of rainfall and water residence time on composition and biomass
Authors: Badylak Susan , Phlips Edward , Dix Nicole , Hart Jane , Srifa Akeapot , Haunert Daniel , He Zenli , Lockwood Jean , Stofella Peter , Sun Detong , Yang Yaugen
Published: July 2015

Concerns about global climate change have heightened awareness of the role changing rainfall regimes play in altering plankton communities of coastal ecosystems. In this study spatial and temporal patterns of phytoplankton composition and biomass in a sub-tropical tidal creek in Florida were observed over three wet and dry seasons, which included the major storm year of 2005 and the drought year of 2006. Shifts in rainfall levels were associated with changes in phytoplankton composition and biomass, but the effects varied between the upper and lower reaches of the creek. The upper reach of the creek was fresh throughout the study period. The oligohaline to mesohaline lower creek alternated between fresh and marine species in response to shifts in salinity regimes. Blooms of the freshwater dinoflagellate Peridinium sp., small centric diatoms and nitrogen-fixing cyanobacteria were common in the upper Ten Mile Creek during low rainfall years. The euryhaline marine dinoflagellate Akashiwo sanguinea and centric diatoms (e.g. Leptocylindrus minimus) were observed at bloom levels in the lower creek during low to average rainfall periods. The results are discussed within the context of how variability in rainfall influence water residence times, nutrient concentrations and salinity regimes, which in turn influence phytoplankton composition and biomass.
What factors affect the density of cane toads (Rhinella marina) in the Solomon Islands?
Authors: Pikacha Patrick , Lavery Tyrone , Leung Luke K.-P.
Published: July 2015

Cane toads (Rhinella marina) were introduced to the Solomon Islands in the 1940s, and quickly spread across the archipelago. Between May 2009 and August 2012, cane toads were recorded on 11 of 13 islands surveyed, and the densities of toads were estimated by distance sampling on seven of these islands. Modified Akaike’s Information Criterion (AICc) tests were used to find the most parsimonious model for cane toad density in the Solomon Islands. The results showed that mean toad density was higher on Gatokae and Guadalcanal than on Bougainville, Choiseul, Kolombangara and Rendova. A plausible explanation for this is that Guadalcanal had an abundance of breeding sites, and that Gatokae may have been recently colonised with a typical sharp rise in toad densities. The model also showed that mean toad density was higher in coastal forests than in other forest types (e.g lowland, hill and montane forests). Coastal forests have higher disturbance levels as a result of villages and towns. Disturbance was associated with increased toad densities in the model. These findings suggest that cane toad management efforts should target coastal forests and disturbed areas along roads and tracks leading to important biodiversity reserves.
Seeing in colour: a hundred years of studies on bee vision since the work of the Nobel laureate Karl von Frisch
Authors: Dyer Adrian G. , Garcia Jair E. , Shrestha Mani , Lunau Klaus
Published: July 2015

One hundred years ago it was often assumed that the capacity to perceive colour required a human brain. Then in 1914 a young Austrian researcher working at Munich University in Germany published evidence that honeybees could be trained to collect sugar water from a ‘blue’ coloured card, and find the colour among a number of different shades of achromatic grey. Von Frisch thus established honeybees as an important model of sensory processing in animals, and for work including his demonstration that bees used a symbolic dance language, won a Nobel Prize in 1973. This work led to the establishment of several research groups in Germany that developed a rich understanding of how bee vision has shaped flower colour evolution in the Northern Hemisphere. Applying these insights to Australian native bees offers great insights due to the long-term geological isolation of the continent. Australian bees have a phylogenetically ancient colour visual system and similar colour perception to honeybees. In Australia similar patterns of flower colour evolution have resulted and provide important evidence of parallel evolution, thanks to the pioneering work of Karl von Frisch 100 years ago.
Experimental analysis of fire spread across a two-dimensional ridge under wind conditions
Authors: Raposo J. R. , Cabiddu S. , Viegas D. X. , Salis M. , Sharples J.
Published: July 2015

Results from a laboratory-scale investigation of a fire spreading on the windward face of a triangular-section hill of variable shape with wind perpendicular to the ridgeline are reported. They confirm previous observations that the fire enlarges its lateral spread after reaching the ridgeline, entering the leeward face with a much wider front. Reference fire spread velocities were measured and analysed, putting in evidence the importance of the dynamic effect due to flow velocity and its associated horizontal-axis separation vortex strength without dependence on hill geometry. Similar parameters estimated from three forest fires compared favourably with the laboratory-scale measurements.
Carbon footprint from helitankers: sustainable decision making in aerial wildfire fighting
Authors: Alvarez Sergio , Planelles Rosa , Rubio Agustín
Published: July 2015

Carbon footprint (CF) can be a key factor stimulating innovation while driving sustainable decision making. The air transport sector and wildfires are considered to be relevant contributors to greenhouse gas emissions. Among the available resources for wildfire suppression, aerial firefighting – particularly using helitankers – is the most effective method. However the high economic costs and fuel-related emissions incurred by helitankers prevent their widespread use. This work aims to calculate the CF from helitankers in order to assess this new indicator for sustainable decision making. The CF is calculated here by a compound method based on the financial accounts of a Spanish company that owns 20 helitankers. The total cumulative corporate CF in 2012 was 5497 t CO2 equivalents. We discuss the influence of the method, its implications and future actions for the reduction of greenhouse gas emissions. Our experience should be considered as a pilot study providing further evidence of the value of using sustainable indicators in decision making.
Suppression of conformational heterogeneity at a protein–protein interface
Authors: Deis Lindsay N. , Wu Qinglin , Wang You , Qi Yang , Daniels Kyle G. , Zhou Pei , Oas Terrence G.
Published: July 2015

Significance

The emergence of antibiotic-resistant strains of bacteria, such as methicillin-resistantStaphylococcus aureus, is an increasing threat to human health.S. aureusinfections cause a variety of health complications, ranging from skin lesions to life-threatening infections. Staphylococcal protein A (SpA) is the major cell-surface protein and a multitarget virulence factor. The design of SpA-targeted therapeutics requires a molecular description of its interactions with host proteins. Here we report the crystal structure of a complete SpA domain in complex with an Fcfragment of human IgG. Our structure reveals changes in SpA when it binds to Fc, including a significant reduction in conformational heterogeneity as well as displacement of a SpA side chain by an Fcside chain in a molecular-recognition pocket.
Structure of LacY with an α-substituted galactoside: Connecting the binding site to the protonation site
Authors: Kumar Hemant , Finer-Moore Janet S. , Kaback H. Ronald , Stroud Robert M.
Published: July 2015

Significance

Substituted
d
-galactopyranosides, particularly those in the α configuration and/or with hydrophobic constituents at the anomeric position, bind to LacY with higher affinity than the physiological substrate lactose that has a β configuration. The structure of a conformationally restricted LacY mutant with bound
p
-nitrophenyl-α-
d
-galactopyranoside (α-NPG), a high-affinity lactose analog, is described. Higher affinity, gained by nonspecific hydrophobic interaction of the nitrophenyl group, shows identical interaction at the key galactosyl moiety as in thio-digalactoside and so validates the highly specific, oriented set of hydrogen bonds with the key galactosyl moiety of substrates. Confirmation of galactose-specific binding interactions delineates a directional hydrogen-bonding network that couples the binding site to sites that are sensitive to protonation in the mechanism.
Between “ethnocide” and “genocide”: violence and Otherness in the coverage of the Afghanistan and Chechnya wars
Authors: Casula Philipp
Published: July 2015

The Soviet occupation of Afghanistan and the two Russian wars in Chechnya were the longest, most protracted conflicts of the USSR and Russia after WWII. Both were conducted under conditions of unprecedented violence in peripheral territories. Despite their distance in time and space, both wars are closely linked to each other on the level of cultural representations in contemporary Russia. This paper analyses how the conflicts were represented in a key Soviet and Russian newspaper as the wars unfolded. It analyses the textual and visual coverage of the wars in theKrasnaia zvezda(1980–1986; 2000–2003), in order to disclose changing interpretations of violence and the Other. The paper argues, first, thatKrasnaia zvezdatold the story of two different types of violence prevailing in each conflict. The Afghan case was presented as one that put the social and cultural transformation of the population at the center of its attention – violence was hence not only physical and excessive but also cultural, as it aimed at the social fabric of society. The Chechen case focused on the recapture of territory and the restoration of sovereignty. Therefore, physical violence appeared more bluntly in the coverage of the conflict. Second, the paper shows that these two different types of violence implied two different visions of the Other. In Afghanistan, the Other was represented as becoming more and more similar to the socialist Self. This dynamic is visually underscored by numerous images of Afghans who have embarked on the path to Soviet modernity. In Chechnya, in contrast, the Other was presented as traditional, backward, and immutable. The Other was usually reduced to complete cultural difference and depicted a dehumanized fashion. This orientalization of the Other was a precondition for the use of excessive physical violence.
Effects of Increased Discharge on Spawning and Age-0 Recruitment of Rainbow Trout in the Colorado River at Lees Ferry, Arizona
Authors: Avery Luke A. , Korman Josh , Persons William R.
Published: July 2015

Negative interactions of Rainbow Trout Oncorhynchus mykiss with endangered Humpback Chub Gila cypha pose challenges to the operation of Glen Canyon Dam (GCD) to manage for both species in the Colorado River. Operations to enhance the Rainbow Trout tailwater fishery may lead to an increase in downstream movement of the trout to areas where they are likely to interact with Humpback Chub. We evaluated the effects of dam operations on age-0 Rainbow Trout in the tailwater fishery to inform managers about how GCD operations could benefit a tailwater fishery for Rainbow Trout; although this could affect a Humpback Chub population farther downstream. A near year-long increase in discharge at GCD in 2011 enabled us to evaluate whether high and stable flows led to increased spawning and production of age-0 Rainbow Trout compared with other years. Rainbow Trout spawning was monitored by fitting a model to observed redd counts to estimate the number of redds created over a spawning season. Data collected during electrofishing trips in July–September and November were used to acquire age-0 trout population and mortality rate estimates. We found that high and stable flows in 2011 resulted in 3,062 redds (1.7 times the mean of all survey years) and a population estimate of 686,000 age-0 Rainbow Trout (second highest on record). Despite high initial abundance, mortality remained low through the year (0.0043%/d) resulting in significant recruitment with a record high November population estimate of 214,000 age-0 Rainbow Trout. Recent monitoring indicates this recruitment event was followed by an increase in downstream migration, which may lead to increased interactions with downstream populations of Humpback Chub. Consequently, while our results indicate that manipulating flow at GCD can be used to manage Rainbow Trout spawning and recruitment, fisheries managers should use flow manipulation in moderation to minimize downstream migration in order to reduce negative interactions with other species in the Colorado River.

Received September 8, 2014; accepted March 28, 2015
Estimating Regional Fishing Mortality for Freshwater Systems: a Florida Largemouth Bass Example
Authors: Kerns Janice A. , Allen Micheal S. , Dotson Jason R. , Hightower Joseph E.
Published: July 2015

Species-specific harvest regulations in recreational fisheries are commonly applied regionally to protect stocks from overharvest and satisfy a diverse set of anglers. While setting regulations is a complex task and may incorporate the best available social and biological information, fisheries managers commonly obtain directed fishing mortality estimates within a single lake and then assume similar rates among other systems when setting regional harvest regulations. Thus, there is a need to assess regional levels of fishing mortality for informed use of regionally applied regulations. We implemented a practical method for assessing catch and harvest for a recreational fishery across a broad spatial region. We used a passive tag-reward study design and a regional management regulation area for Florida Largemouth Bass Micropterus salmoides floridanus in central Florida as our case study. The estimated fishing mortality rate included both harvest and deaths due to catch and release. We found overall regional fishing mortality for Florida Largemouth Bass in central Florida was relatively low. From the 247 dart tags returned, the mean annual instantaneous total fishing mortality rate was 0.11 (95% credible interval = 0.08–0.15). We also found fishing mortality rates did not vary with lake size or fish total length. Our study design did not provide mortality estimates for any specific lake due to a low number of tagged fish per lake, but the method could be used to elucidate the effectiveness of regulations that are applied at a regional scale.

Received November 20, 2014; accepted March 31, 2015