bluuebunny/crossref_metadata_2025 huggingface dataset:
A family of asymptotically hyperbolic manifolds with arbitrary energy-momentum vectors
Authors: Cortier Julien
Published: October 2012

A family of non-radial solutions to the Yamabe equation, modeled on the hyperbolic space, is constructed using power series. As a result, we obtain a family of asymptotically hyperbolic metrics, with spherical conformal infinity, with scalar curvature greater than or equal to −n(n − 1), but which are a priorinot complete. Moreover, any vector of \documentclass[12pt]{minimal}\begin{document}$\mathbb {R}^{n+1}$\end{document}Rn+1 is performed by an energy-momentun vector of one suitable metric of this family. They can in particular provide counter-examples to the positive energy-momentum theorem when one removes the completeness assumption.
Differential-algebraic and bi-Hamiltonian integrability analysis of the Riemann hierarchy revisited
Authors: Prykarpatsky Yarema A. , Artemovych Orest D. , Pavlov Maxim V. , Prykarpatsky Anatoliy K.
Published: October 2012

A differential-algebraic approach to studying the Lax integrability of the generalized Riemann type hydrodynamic hierarchy is revisited and its new Lax representation is constructed in exact form. The bi-Hamiltonian integrability of the generalized Riemann type hierarchy is discussed by means of the gradient-holonomic and symplectic methods and the related compatible Poissonian structures for N = 3 and N = 4 are constructed.
Coherent versus incoherent excitation energy transfer in molecular systems
Authors: Chang Hung-Tzu , Cheng Yuan-Chung
Published: October 2012

We investigate the Markovian limit of a polaronic quantum master equation for coherent resonance energy transfer proposed recently by Jang et al. [J. Chem. Phys. 129, 101104 (2008)10.1063/1.2977974]. An expression for the rate of excitation energy transfer (EET) is derived and shown to exhibit both coherent and incoherent contributions. We then apply this theory to calculated EET rates for model dimer systems, and demonstrate that the small-polaron approach predicts a variety of dynamical behaviors. Notably, the results indicate that the EET dynamical behaviors can be understood by the interplay between noise-assisted EET and dynamical localization, while both are well captured by the polaron theory. Finally, we investigate bath correlation effects on the rate of EET and show that bath correlations (or anti-correlations) can either enhance or suppress EET rate depending on the strength of individual system-bath couplings. In summary, we introduce the small-polaron approach as an intuitive physical framework to consolidate our understanding of EET dynamics in the condensed phase.
An “edge to edge” jigsaw-puzzle two-dimensional vapor-phase transport growth of high-quality large-area wurtzite-type ZnO (0001) nanohexagons
Authors: Li Jian-Min , Dai Long-Gui , Wan Xiao-Ping , Zeng Xian-Lin
Published: October 2012

The authors reported the synthesis of large but thin transparent regularly shaped single-crystalline zinc oxide (ZnO) (0001) hexagonal nanodisks (or nanohexagons) (the most probable area scale of 95 μm2 and 40–70 nm in thickness) by an indium assisted vapor-phase transport (VPT) growth route at ambient pressure. These large-area ZnO nanohexagons exhibit excellent luminescent properties with a strong ultraviolet emission band centered at about 384 nm and a very weak green band shoulder emission, leading to the further creation of a promising low-defect-concentration nanohexagons-based nanooptoelectronics. Finally, a two-dimensional VPT growth mechanism was proposed to understand the formation of high-quality wurtzite-type ZnO nanohexagons.
Coaction and competition between the ferroelectric field effect and the strain effect in Pr0.5Ca0.5MnO3 film/0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 crystal heterostructures
Authors: Zhu Q. X. , Wang W. , Yang S. W. , Li X. M. , Wang Y. , Habermeier H.-U. , Luo H. S. , Chan H. L. W. , Li X. G. , Zheng R. K.
Published: October 2012

The coaction and competition between the ferroelectric field effect and the strain effect in Pr0.5Ca0.5MnO3 (PCMO) film/0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 crystal heterostructures were studied. Based on different types of resistance-electric field hysteresis loops at various temperatures, it is clearly identified that the strain effect dominates over the ferroelectric field effect for temperature T above the charge-ordering temperature TCO of PCMO. With the strong localization of charge carriers for T < TCO, the ferroelectric field effect strongly competes with the strain effect and finally dominates over the latter for T < 0.8TCO. Moreover, the poling-induced strain effect is considerably enhanced by a magnetic field, demonstrating the important role of the phase separation in understanding the strain effect in such heterostructures.
High Seebeck effects from conducting polymer: Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) based thin-film device with hybrid metal/polymer/metal architecture
Authors: Stanford Michael , Wang Hsin , Ivanov Ilia , Hu Bin
Published: October 2012

Conductive polymers are of particular interest for thermoelectric applications due to their low thermal conductivity and relatively high electrical conductivity. In this study, commercially available conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) was used in a hybrid metal/polymer/metal thin film design in order to achieve a high Seebeck coefficient with the value of 252 μV/k on a relatively low temperature scale. Polymer film thickness was varied in order to investigate its influence on the Seebeck effect. The high Seebeck coefficient indicates that the metal/polymer/metal design can develop a large entropy difference in internal energy of charge carriers between high and low-temperature metal electrodes to develop electrical potential due to charge transport in conducting polymer film through metal/polymer interface. Therefore, the metal/polymer/metal structure presents a new design to combine inorganic metals and organic polymers in thin-film form to develop Seebeck devices.
Optoacoustic measurements of the porosity of paper samples with foxings
Authors: Balakhnina I. A. , Brandt N. N. , Chikishev A. Yu. , Pelivanov I. M. , Rebrikova N. L.
Published: October 2012

The goal of this work is to investigate the porosity of old paper with foxings. Initially, paper samples are characterized using the conventional absorption and Fourier transform infrared spectroscopies. Optoacoustic method based on laser excitation of short ultrasound transients is used for porosity measurements. The paper porosity is calculated using the theory of two-component mixture with the experimentally determined sound speeds in paper samples saturated with liquids. An increase in the porosity in foxing stains on paper in comparison with the foxing-free fragments is clearly demonstrated.
Gold coating of micromechanical DNA biosensors by pulsed laser deposition
Authors: Rebollar Esther , Sanz Mikel , Esteves Carina , Martínez Nicolás F. , Ahumada Óscar , Castillejo Marta
Published: October 2012

In this work, we describe the gold-coating of silicon microcantilever sensors by pulsed laser deposition (PLD) and their performance as DNA biosensors. To test optimum deposition conditions for coating the sensors, silicon substrates were gold coated by PLD using the fifth harmonic of a Nd:YAG laser (213 nm, pulse duration 15 ns). The gold deposits were characterized by atomic force microscopy and x-ray diffraction. The adequate conditions were selected for coating the sensors with a 20 nm thick gold layer and subsequently functionalized with a self-assembled monolayer of thiolated DNA. To verify PLD as a tool for gold coating of biomechanical sensors, they were characterized by using a scanning laser analyzer platform. Characterization consisted in the measurement of the differential stress of the cantilevers upon hydration forces before and after functionalization with a double-stranded DNA monolayer. The measurements showed that the sensor surface stress induced by the adsorption of water molecules is approximately seven times higher than that of functionalized sensors gold coated by thermal evaporation. These results indicate that gold coating by PLD could be an advantageous method to enhance the response of biomechanical sensors based on gold-thiol chemistry.
Surface tension effects on submerged electrosprays
Authors: Marín Álvaro G. , Loscertales Ignacio G. , Barrero Antonio
Published: October 2012

Electrosprays are a powerful technique to generate charged micro/nanodroplets. In the last century, the technique has been extensively studied, developed, and recognized with a shared Nobel price in Chemistry in 2002 for its wide spread application in mass spectrometry. However, nowadays techniques based on microfluidic devices are competing to be the next generation in atomization techniques. Therefore, an interesting development would be to integrate the electrospray technique into a microfluidic liquid-liquid device. Several works in the literature have attempted to build a microfluidic electrospray with disputable results. The main problem for its integration is the lack of knowledge of the working parameters of the liquid-liquid electrospray. The “submerged electrosprays” share similar properties as their counterparts in air. However, in the microfluidic generation of micro/nanodroplets, the liquid-liquid interfaces are normally stabilized with surface active agents, which might have critical effects on the electrospray behavior. In this work, we review the main properties of the submerged electrosprays in liquid baths with no surfactant, and we methodically study the behavior of the system for increasing surfactant concentrations. The different regimes found are then analyzed and compared with both classical and more recent experimental, theoretical and numerical studies. A very rich phenomenology is found when the surface tension is allowed to vary in the system. More concretely, the lower states of electrification achieved with the reduced surface tension regimes might be of interest in biological or biomedical applications in which excessive electrification can be hazardous for the encapsulated entities.
Investigations on loop antenna excited whistler waves in a cylindrical plasma based on laboratory experiments and simulations
Authors: Pfannmöller J. P. , Lechte C. , Grulke O. , Klinger T.
Published: October 2012

Experimental investigations and simulations of loop antenna excited whistler waves in a cylindrical low temperature plasma are presented. Experiments are performed in the VINETA [Franck et al., Plasma Sources Sci. Technol. 14, 226 (2005)] device and simulations are generated using IPF-FD3D [C. Lechte, IEEE Trans. Plasma Sci. 37, 1099 (2009)], an implementation of the Yee-algorithm. A good agreement of the experiment and the simulation is found. The simulation is used to predict the spatial structure of the wave, the dominant source of the electric field, the relative contribution of electron, and displacement current as well as parallel and perpendicular currents to the magnetic field of the wave.
A simple maximum power point tracking based control strategy applied to a variable speed squirrel cage induction generator
Authors: Merabet Boulouiha H. , Allali A. , Tahri A. , Draou A. , Denaï M.
Published: October 2012

This paper presents a comprehensive modelling and control study of a variable speed wind energy conversion system based on a squirrel-cage induction generator (SCIG). The mathematical model of the SCIG is derived in Park frame along with the indirect field oriented control (IFOC) scheme based on a proportional and integral speed controller. A simple maximum power point tracking strategy is used to determine the optimal speed under variable wind speed conditions which is then used as the reference in the IFOC scheme. Power flow between the supply and the inverter is regulated via simultaneous control of the active and reactive currents of the grid and the DC link voltage. The simulation results show that the proposed control technique is able to maximise the energy extracted from the wind during the simulation scenarios considered. The results also demonstrate good transient response characteristics in the decoupled real and reactive powers.
Effect of load variations on exergy performance of solar box type cooker
Authors: Kumar Naveen , Vishwanath G. , Gupta Anurag
Published: October 2012

In recent times, performing the exergy based analysis on solar cookers has gained momentum. It has been observed that the variations in exergy output power and exergy power lost with temperature difference are qualitatively similar in nature for various topological designs of solar cookers. In the present manuscript, variations in the exergy power output and exergy power lost with temperature difference for different loads/mass of water have been reported for solar box type cooker. The four different benchmark parameters, viz., heat loss coefficient, quality factor, peak exergy, and exergy temperature difference gap product are determined for each case. The mutual dependence of these parameters and the conceptual understanding of their variations with different load of water are explained. The adjusted value of the quality factor has been found to be independent of the mass of water kept inside the cooker during full load tests. The findings also confirm the earlier reports in terms of qualitative response and strengthen the case of exergy based test protocol for solar cookers.
Effect of diamond like carbon layer on heat dissipation and optoelectronic performance of vertical-type InGaN light emitting diodes
Authors: Horng Ray-Hua , Kao Wei-Cheng , Ou Sin-Liang , Wuu Dong-Sing
Published: October 2012

This study reports the transfer of InGaN light-emitting diodes (LEDs) embedded with and without a diamond like carbon (DLC) layer to Si substrates. It also investigates the heat dissipation and output power performance after the addition of the DLC layer. The LED device with a DLC layer had a lower thermal resistance (13.2 K/W) and surface temperature (55.51-65.34 °C at 700 mA) than that without a DLC layer. This likely resulted from the fast heat dissipation of the DLC layer in both vertical and horizontal directions. The LED device with a DLC layer achieved a 20.8% improvement in output power.
Spin Hall effect of light reflected from a magnetic thin film
Authors: Ren Jinli , Li Yan , Lin Yida , Qin Yi , Wu Rui , Yang Jinbo , Xiao Yun-Feng , Yang Hong , Gong Qihuang
Published: October 2012

The displacements for |P> polarization (electric field parallel to the plane-of-incidence) and |S> polarization (electric field perpendicular to the plane-of-incidence) induced by the spin Hall effect of light reflected from a magnetic cobalt thin film have been investigated. The significant differences from those of an air-glass interface are attributed to the special complex permittivity and refractive index of the cobalt film. The real part of the complex refractive index has more influence on displacements for |P> polarization than for |S> polarization. There also exists a particular incident angle corresponding to the zero displacement for |P> polarization. It shifts from 52° to 76° when the real part rises from 1.0 to 4.0. For both |P> and |S> polarizations, the maximal displacements rapidly rise with the decrease of the imaginary part. Our simulations further demonstrate that polarization-insensitive spin separations can be realized by choosing the medium with an optimal permeability.
Polarization-stable vertical-cavity surface-emitting lasers with inverted grating relief for use in microscale atomic clocks
Authors: Al-Samaneh A. , Bou Sanayeh M. , Miah M. J. , Schwarz W. , Wahl D. , Kern A. , Michalzik R.
Published: October 2012

Vertical-cavity surface-emitting lasers (VCSELs) with single-mode, single-polarization emission at a wavelength of 894.6 nm have become attractive light sources for miniaturized Cs-based atomic clocks. So far, VCSELs used for these applications are single-mode because of small active diameters which has the drawbacks of increased ohmic resistance and reduced lifetime. By employing surface grating reliefs, enhanced fundamental-mode emission as well as polarization-stable laser oscillation are achieved. VCSELs with 5 μm active diameter show side-mode suppression ratios of 20 dB even at currents close to thermal roll-over with orthogonal polarization suppression ratios better than 20 dB at elevated ambient temperatures up to 100 °C.
Surface roughness effects on the corona discharge intensity of long-term operating conductors
Authors: Bian X. M. , Chen L. , Yu D. M. , Wang L. M. , Guan Z. C.
Published: October 2012

An investigation into the effect of surface roughness on corona discharge intensity of long-term operating conductors is presented. The electric field distortion level was found to increase linearly with surface average roughness Ra. At the corona inception voltages, the ionization intensity ξ in the ionization zone was calculated, it would increase exponentially with the raise of Ra. As a result, the corona discharge intensity of long-term operating conductors was stronger, and the corona inception voltages were lower than those of the new conductors. The deviation of radio noise and audible noise was found to increase linearly with the raise of Ra.
Microwave assisted resonant domain wall nucleation in permalloy nanowires
Authors: Hayashi Masamitsu , Takahashi Yukiko K. , Mitani Seiji
Published: October 2012

We have designed a system to study microwave assisted domain wall nucleation in permalloy nanowires. We find a substantial decrease in the nucleation field when microwave fields are applied, in comparison to pulse fields. A clear resonance peak is observed in the frequency dependence of the nucleation field, which coincides with the uniform mode ferromagnetic resonance frequency. Owing to the well-defined nucleation process, the switching field distribution is small in contrast to previous reports. Our results show that localized microwave field provides an efficient tool for injecting domain walls into magnetic nanowires.
Critical flux ratio of hydrogen radical to film precursor in microcrystalline silicon deposition for solar cells
Authors: Abe Yusuke , Fukushima Atsushi , Takeda Keigo , Kondo Hiroki , Ishikawa Kenji , Sekine Makoto , Hori Masaru
Published: October 2012

The properties of thin-film silicon grown by plasma enhanced chemical vapor deposition were investigated with respect to the flux ratio of hydrogen radical to film precursor. The absolute density and translational temperature of H radicals in SiH4/H2 capacitively coupled plasma were measured using vacuum ultraviolet laser absorption spectroscopy. The flux of effective H radicals to the surface reactions was estimated from the results. The flux of effective film precursor for deposition was estimated from the deposition rate, so that the critical flux ratio of H radicals to film precursor to obtain suitable film properties was identified to be approximately 65–70.
Voltage-gated modulation of domain wall creep dynamics in an ultrathin metallic ferromagnet
Authors: Bauer Uwe , Emori Satoru , Beach Geoffrey S. D.
Published: October 2012

The influence of gate voltage, temperature, and magnetic field on domain wall (DW) creep dynamics is investigated in Pt/Co/gadolinium oxide (GdOx) films with perpendicular magnetic anisotropy and imaged by a scanning magneto-optical Kerr effect technique. The DW creep velocity can be controlled by an electric field applied to the Co/GdOx interface via a linear modulation of the activation energy barrier with gate voltage. At low speeds, the DW velocity can be changed significantly by a gate voltage, but the effect is diminished as the DW velocity increases, which limits electric field control of fast DW motion.
Broadband plate-type acoustic metamaterial for low-frequency sound attenuation
Authors: Badreddine Assouar M. , Senesi Matteo , Oudich Mourad , Ruzzene Massimo , Hou Zhilin
Published: October 2012

We show experimentally that plate-type acoustic metamaterials can serve to totally prohibit low frequency structure-borne sound at selective resonance frequencies ranging from 650 to 3500 Hz. Our metamaterial structures are consisting of a periodic arrangement of composite stubs (tungsten/silicone rubber) deposited on a thin aluminium plate. We report that these metamaterials present a broadband gap of out-of-plane modes at frequencies where the relevant sound wavelength in air is about three orders of magnitude larger than the plate thickness. Confinement and waveguiding of structure-borne sound in this sub-wavelength resonant regime is also experimentally evidenced and discussed.
Direct observation of guided-mode interference in polymer-loaded plasmonic waveguide
Authors: Cheng Q. Q. , Li T. , Guo R. Y. , Li L. , Wang S. M. , Zhu S. N.
Published: October 2012

We report a direct observation of guided-mode interference in polymer-loaded plasmonic waveguides by the technique of leakage radiation microscopy (LRM). Spatial beating patterns of the interferences were clearly characterized with respect to different structural parameters, and the interference properties were analyzed in detail. Besides, the capability of LRM for characterizing the multiple modes was also discussed extensively. Our finding not only offers an efficient technique in analyzing the guided modes and their interference, but also provides a definite guideline in evaluating the validity of LRM and deepens further studies on the dielectric-loaded hybrid waveguide system.
Importance of interface roughness induced intersubband scattering in mid-infrared quantum cascade lasers
Authors: Chiu YenTing , Dikmelik Yamac , Liu Peter Q. , Aung Nyan L. , Khurgin Jacob B. , Gmachl Claire F.
Published: October 2012

The electron transit time of many different quantum cascade lasers has been measured and compared to the calculated upper laser level lifetimes with and without taking into account interface roughness induced intersubband scattering. A significantly better correlation is found between the experimental results and the calculation when including the contribution from the interface roughness (corr. coeff.: 0.79 vs. 0.43 with and without the consideration of interface roughness, respectively). This suggests that in addition to longitudinal optical phonons, interface roughness is also crucial in determining the intersubband lifetimes in mid-infrared quantum cascade laser and should routinely be included in design.
Superelastic memory effect in in-situ NbTi-nanowire-NiTi nanocomposite
Authors: Hao Shijie , Cui Lishan , Jiang Daqiang , Wang Yandong , Shi Xiaobing , Jiang Jiang , Brown Dennis E. , Ren Yang
Published: October 2012

An in-situ NbTi-nanowire-NiTi composite wire fabricated by conventional metallurgical processing has the remarkable ability of remembering its previous stress/strain states where it was unloaded during multiple-step cyclic loading. In situ synchrotron x-ray diffraction studies revealed that an interactive stress between NbTi nanowires and NiTi matrix was introduced and retained after a load/unload cycle due to their strain mismatch. The different levels of interactive stress in different regions of the specimen resulted in a superelastic memory effect. Furthermore, the final loading curve could remember all previous loading histories, which may be of use in practical applications.
Cost-effective and high frequency surface acoustic wave filters on ZnO:Fe/Si for low-loss and wideband application
Authors: Luo J. T. , Pan F. , Fan P. , Zeng F. , Zhang D. P. , Zheng Z. H. , Liang G. X.
Published: October 2012

ZnO:Fe films with various piezoelectric coefficient d33 were employed to fabricate high frequency surface acoustic wave (SAW) filters on Si by conventional photolithography technology. Comparing with the SAW filters on undoped ZnO films, the electromechanical coupling factor and bandwidth, respectively, increases 75.7% and 14.8%, while the insertion loss decreases 20.3% when using Zn0.988Fe0.012O films with a d33 of ∼127 pC/N. Through annealing demonstration, d33 is considered as the intrinsic factor determining the SAW properties of filters, and the properties are improved by O2 annealing. ZnO:Fe films with enhanced d33 is promising for high frequency, low-loss, and wideband SAW applications.
Spin polarization of Zn1−xCoxO probed by magnetoresistance
Authors: Li Q. , Shen T. T. , Dai Z. K. , Cao Y. L. , Yan S. S. , Kang S. S. , Dai Y. Y. , Chen Y. X. , Liu G. L. , Mei L. M.
Published: October 2012

The spin polarization of Zn0.32Co0.68O1−v (v means oxygen vacancies) concentrated magnetic semiconductor (CMS) films was extracted from measurements of tunneling magnetoresistance (TMR), and spin-dependent variable range hopping, respectively. A TMR ratio of 19.1% was observed at 2 K in Co/ZnO/Zn0.32Co0.68O1−v magnetic tunnel junctions, which gives a low limit of the spin polarization of 25% in the Zn0.32Co0.68O1−v CMS. The TMR decreases with increasing temperature and bias voltage mainly due to the tunneling via localized impurity states in the barrier. By contrast, the spin polarization of the Zn0.32Co0.68O1−v CMS was estimated to be 36.1% by spin-dependent variable range hopping.
An oversized X-band transit radiation oscillator
Authors: Cao Yibing , He Juntao , Zhang Jiande , Zhang Jun , Jin Zhenxing
Published: October 2012

An oversized transit radiation oscillator is designed to generate high power microwave at X-band. By using a coaxial structure, the power capacity of the device is improved significantly. In order to realize long-pulse operation, the cathode-anode gap, the collector location, and the surface field strength have been emphatically considered in our design. With a 710 kV, 14.5 kA beam guided by a 0.8 T magnetic field, a 2.7 GW microwave at 9.38 GHz has been obtained in the simulation. The power conversion efficiency is 26.2%. The simulation also indicates that the highest axial electric field strength on the surface of electrodynamic structure is only 590 kV/cm, which could be further decreased by increasing the radial dimension of the X-band device.
Polycrystalline ZnO Mott-barrier diodes
Authors: Liu Zi-Jheng , Huang Hsin-Wei , Gan Jon-Yiew , Yew Tri-Rung
Published: October 2012

This study reports the fabrication of polycrystalline ZnO Mott-barrier diodes at room temperature by sputtering deposition. Fundamental and systematic analyses of the diodes were conducted using current-voltage (I-V), capacitance-voltage (C-V), pulse-response, varying-temperature measurements, and reliability tests. The proposed diodes had a high rectifying ratio of 4.7 × 104 at ± 1.2 V, a fast switching speed of <50 ns, and stable rectification under a ±2 V pulse stress up to 1010 cycles. These results demonstrate polycrystalline ZnO Mott-barrier diodes' potential for future applications.
A facile approach for shape selective synthesis of rhodium nanostructures and conductivity studies
Authors: Sathe Bhaskar R.
Published: October 2012

Shape selective synthesis of Rh nanostructures has been demonstrated with the help of a single step chemical vapor deposition, where different shapes like cubes at 500 °C, pyramids and hexagons at 500 °C, 700 °C and 900 °C respectively have been obtained as a function of temperature. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and four probe conductivity measurements were used to study the morphology, crystallinity and phase purity of the structures. The conductivity values for as synthesised nanostructures have been obtained in the range of 2-7 kS/cm2. On the basis of the experimental results, from TGA and XPS studies possible mechanistic pathway for the evolution of Rh nanostructures was discussed.
Single-waveguide dual-wavelength interband cascade lasers
Authors: Li Lu , Zhao Lihua , Jiang Yuchao , Yang Rui Q. , Keay Joel C. , Mishima Tetsuya D. , Santos Michael B. , Johnson Matthew B.
Published: October 2012

Dual-wavelength interband cascade (IC) lasers with two different cascade regions in a single waveguide have been demonstrated in pulsed conditions to simultaneously lase based on spatially overlapping fundamental vertical modes near 5 and 6 μm. The fabricated broad-area devices operate at temperatures up to 155 K and 235 K in cw and pulsed modes, respectively. The temperature dependence of the device performance characteristics has been investigated. The threshold current of the dual wavelength IC lasers at the shorter wavelength showed different characteristics from that at the longer wavelength.
Bare-nosed wombats (Vombatus ursinus) use drainage culverts to cross roads
Authors: Crook Natasha , Cairns Stuart C. , Vernes Karl
Published: October 2012

Despite drainage culverts being numerous along highways, there is a scarcity of data evaluating their use as roadway underpasses by wildlife, including the bare-nosed wombat (Vombatus ursinus), a large marsupial that is involved in substantial numbers of vehicle collisions in New South Wales. Culvert use was measured with camera traps positioned at 19 drainage culverts along an 8-km stretch of ‘Thunderbolt’s Way’ near Nowendoc on the Northern Tableland, north-eastern New South Wales. The estimated probability of the occupancy/use of a culvert by a wombat was 0.46 ± 0.10. Culvert use was related to structural variables (e.g. diameter and length) and both the distance to the next adjacent culvert and to forest cover. This suggests that wombats readily use drainage culverts to cross under roads and that these structures could be modified (e.g. by maintaining proximate forest cover) to increase the likelihood that wombats would use them, thus reducing vehicle collisions and road mortality of wombats.
A way to reduce interference with Elliott traps
Authors: Page M. J. , Kuiper J. , Kabat A. P. , Legge S.
Published: October 2012

Elliott traps are widely used in Australia to capture small terrestrial mammals. However, in some situations non-target species disturb the traps, resulting in fewer traps being available for the target species. This situation occurred on Faure Island Wildlife Sanctuary (Western Australia) where boodies (burrowing bettongs) were disturbing the Elliott traps deployed to monitor populations of shark bay mice and western barred bandicoots. This note presents the method used to alleviate this problem on Faure Island but would be more widely applicable in other situations where Elliott traps are disturbed by animals other than the target species.
A permanent security post for camera trapping
Authors: Meek Paul D. , Ballard Guy-Anthony , Fleming Peter J. S.
Published: October 2012

As the use of camera traps in wildlife management in Australia rapidly increases, government agencies, private enterprises, universities and individuals are investing considerable amounts of money in camera trap technology for research, monitoring and recreation. Often camera traps need to be placed along vehicle tracks or in obvious locations to detect animal activity. Consequently, units are frequently highly visible and therefore easily located by would-be thieves. We describe a field-tested security post design that increases security for both camera traps and data, whilst also offering a means of standardising placement.
A cellular automata model to link surface fires to firebrand lift-off and dispersal
Authors: Perryman Holly A. , Dugaw Christopher J. , Varner J. Morgan , Johnson Diane L.
Published: October 2012

In spite of considerable effort to predict wildland fire behaviour, the effects of firebrand lift-off, the ignition of resulting spot fires and their effects on fire spread, remain poorly understood. We developed a cellular automata model integrating key mathematical models governing current fire spread models with a recently developed model that estimates firebrand landing patterns. Using our model we simulated a wildfire in an idealised Pinus ponderosa ecosystem. Varying values of wind speed, surface fuel loading, surface fuel moisture content and canopy base height, we investigated two scenarios: (i) the probability of a spot fire igniting beyond fuelbreaks of various widths and (ii) how spot fires directly affect the overall surface fire’s rate of spread. Results were averages across 2500 stochastic simulations. In both scenarios, canopy base height and surface fuel loading had a greater influence than wind speed and surface fuel moisture content. The expected rate of spread with spot fires occurring approached a constant value over time, which ranged between 6 and 931% higher than the predicted surface fire rate of spread. Incorporation of the role of spot fires in wildland fire spread should be an important thrust of future decision-support technologies.
Differential Ly-6C expression identifies the recruited macrophage phenotype, which orchestrates the regression of murine liver fibrosis
Authors: Ramachandran Prakash , Pellicoro Antonella , Vernon Madeleine A. , Boulter Luke , Aucott Rebecca L. , Ali Aysha , Hartland Stephen N. , Snowdon Victoria K. , Cappon Andrea , Gordon-Walker Timothy T. , Williams Mike J. , Dunbar Donald R. , Manning Jonathan R. , van Rooijen Nico , Fallowfield Jonathan A. , Forbes Stuart J. , Iredale John P.
Published: October 2012

Although macrophages are widely recognized to have a profibrotic role in inflammation, we have used a highly tractable CCl
4
-induced model of reversible hepatic fibrosis to identify and characterize the macrophage phenotype responsible for tissue remodeling: the hitherto elusive restorative macrophage. This CD11B
hi
F4/80
int
Ly-6C
lo
macrophage subset was most abundant in livers during maximal fibrosis resolution and represented the principle matrix metalloproteinase (MMP) -expressing subset. Depletion of this population in
CD11B
promoter–diphtheria toxin receptor (CD11B-DTR) transgenic mice caused a failure of scar remodeling. Adoptive transfer and in situ labeling experiments showed that these restorative macrophages derive from recruited Ly-6C
hi
monocytes, a common origin with profibrotic Ly-6C
hi
macrophages, indicative of a phenotypic switch in vivo conferring proresolution properties. Microarray profiling of the Ly-6C
lo
subset, compared with Ly-6C
hi
macrophages, showed a phenotype outside the M1/M2 classification, with increased expression of MMPs, growth factors, and phagocytosis-related genes, including Mmp9, Mmp12, insulin-like growth factor 1 (Igf1), and Glycoprotein (transmembrane) nmb (Gpnmb). Confocal microscopy confirmed the postphagocytic nature of restorative macrophages. Furthermore, the restorative macrophage phenotype was recapitulated in vitro by the phagocytosis of cellular debris with associated activation of the ERK signaling cascade. Critically, induced phagocytic behavior in vivo, through administration of liposomes, increased restorative macrophage number and accelerated fibrosis resolution, offering a therapeutic strategy to this orphan pathological process.
Temperature‐Related Changes in Habitat Quality and Use by Bonneville Cutthroat Trout in Regulated and Unregulated River Segments
Authors: Hillyard Ryan W. , Keeley Ernest R.
Published: October 2012

The availability of suitable habitat is often viewed as one of most important limiting factors for animal populations. In this study, we examined the composition and spatial distribution of stream habitat based on summer water temperature using airborne thermal imagery, floating temperature surveys, and fixed temperature data loggers in a regulated and unregulated segment of the Bear River in Idaho and Wyoming. We also used temperature‐sensitive radio telemetry tags to measure water temperature in habitats used by Bonneville cutthroat trout Oncorhynchus clarkii utah. We found that when available water temperatures increased in the Bear River, cutthroat trout in the regulated segment continuously selected cooler habitats that followed a similar rate of increase as available water temperatures. In the unregulated segment, cutthroat trout did not select significantly cooler available water temperatures when measured over the entire study period. However, cutthroat trout in the unregulated segment did select cooler water temperatures during the peak period of high water temperatures in July. In the regulated river segment, patches of habitat with hospitable water temperatures were small, infrequent, and widely distributed. Whereas, in the unregulated river segment, habitat patches with hospitable water temperatures were larger, more frequent, and in closer proximity to one another. Our data indicate that during the peak of summer temperatures the availability of habitat below the thermal maxima of cutthroat trout becomes very limited, but they are able to locate and use these small patches of habitat during the warmest part of the summer.
Not a job for those who have brought libraries to crisis
1
Authors: Clarke Desmond
Published: October 2012

Desmond Clarke is a library campaigner. He retired as president and chief executive of International Thomson Publishing Services Group, a division of the Thomson Corporation (now Thomson Reuters) and is a former director of Faber and Faber.
On the closure of public libraries of Oxfordshire
Authors: Pullman Philip
Published: October 2012

Philip Pullman writes books for children. His best known is probably the His Dark Materials trilogy, Northern Lights, The Subtle Knife and The Amber Spyglass. His most contentious probably The Good Man Jesus and the Scoundrel Christ. He writes not so much to explain as to allow the reader’s own imagination to work on his words. The same purpose is at the core of his belief in the value of public libraries. The debate on the role and future of public libraries in the UK was marked by the accusation that authors had their own interests in mind when they objected to library closures. Philip Pullman leapt to the attack. This is an edited version of his mauling of Oxfordshire County Council.
Positive management in libraries: if you build it, they won’t necessarily come
Authors: Lynch Jim , St. V. Fitzgerald Stuart
Published: October 2012

Both Jim Lynch and Stuart Fitzgerald are UK representatives of the American company, Library Systems & Services. LSSI is a private management company working for local authorities wishing to outsource library services. Jim Lynch is also a consultant with Ploszajski Lynch Consulting, specialising in sport, leisure and cultural projects. Stuart Fitzgerald is a management consultant with many years’ experience in procurement and performance management in the private, public and voluntary sectors.
Choosing Here and Now versus There and Later: The Moderating Role of Psychological Distance on Assortment Size Preferences
Authors: Goodman Joseph K. , Malkoc Selin A.
Published: October 2012

Consumers prefer larger assortments, despite the negative consequences associated with choosing from these sets. This article examines the role of psychological distance (temporal and geographical) in consumers’ assortment size decisions and rectifies contradicting hypotheses produced by construal level theory. Six studies demonstrate that while consumers prefer larger assortments when the choice takes place in the here and now, they are more likely to prefer small assortments when choices pertain to distant locations and times. This decrease in preference for large assortments is due to psychological distance increasing the similarity of the options in a category, making them appear more substitutable. This effect of psychological distance reverses when consumers consider desirability/feasibility trade-off information inherent in the assortment size decision. These findings point to important outcomes of psychological distance, resolving opposing predictions of construal level theory, and identify boundary conditions for the well-established notion that consumers are attracted to large assortments.
The Precision of Human-Generated Hand-Hygiene Observations: A Comparison of Human Observation with an Automated Monitoring System
Authors: Sharma Deepti , Thomas Geb W. , Foster Eric D. , Iacovelli Jaclyn , Lea Krista M. , Streit Judy A. , Polgreen Philip M.
Published: October 2012

We compared the observations of nearly 1,400 hand-hygiene-related events recorded by an automated system and by human observers. Observation details differed for 38% of these events. Two likely explanations for these inconsistencies were the distance between the observer and the event and the busyness of the clinic.
Unassembled CD147 is an endogenous endoplasmic reticulum–associated degradation substrate
Authors: Tyler Ryan E. , Pearce Margaret M. P. , Shaler Thomas A. , Olzmann James A. , Greenblatt Ethan J. , Kopito Ron R.
Published: October 2012

Degradation of folding- or assembly-defective proteins by the endoplasmic reticulum–associated degradation (ERAD) ubiquitin ligase, Hrd1, is facilitated by a process that involves recognition of demannosylated N-glycans by the lectin OS-9/XTP3-B via the adaptor protein SEL1L. Most of our knowledge of the machinery that commits proteins to this fate in metazoans comes from studies of overexpressed mutant proteins in heterologous cells. In this study, we used mass spectrometry to identify core-glycoslyated CD147 (CD147(CG)) as an endogenous substrate of the ERAD system that accumulates in a complex with OS-9 following SEL1L depletion. CD147 is an obligatory assembly factor for monocarboxylate transporters. The majority of newly synthesized endogenous CD147(CG) was degraded by the proteasome in a Hrd1-dependent manner. CD147(CG) turnover was blocked by kifunensine, and interaction of OS-9 and XTP3-B with CD147(CG) was inhibited by mutations to conserved residues in their lectin domains. These data establish unassembled CD147(CG) as an endogenous, constitutive ERAD substrate of the OS-9/SEL1L/Hrd1 pathway.
Human Asunder promotes dynein recruitment and centrosomal tethering to the nucleus at mitotic entry
Authors: Jodoin Jeanne N. , Shboul Mohammad , Sitaram Poojitha , Zein-Sabatto Hala , Reversade Bruno , Lee Ethan , Lee Laura A.
Published: October 2012

Recruitment of dynein motors to the nuclear surface is an essential step for nucleus–centrosome coupling in prophase. In cultured human cells, this dynein pool is anchored to nuclear pore complexes through RanBP2–Bicaudal D2 (BICD2) and Nup133– centromere protein F (CENP-F) networks. We previously reported that the asunder (asun) gene is required in Drosophila spermatocytes for perinuclear dynein localization and nucleus–centrosome coupling at G2/M of male meiosis. We show here that male germline expression of mammalian Asunder (ASUN) protein rescues asun flies, demonstrating evolutionary conservation of function. In cultured human cells, we find that ASUN down-regulation causes reduction of perinuclear dynein in prophase of mitosis. Additional defects after loss of ASUN include nucleus–centrosome uncoupling, abnormal spindles, and multinucleation. Coimmunoprecipitation and overlapping localization patterns of ASUN and lissencephaly 1 (LIS1), a dynein adaptor, suggest that ASUN interacts with dynein in the cytoplasm via LIS1. Our data indicate that ASUN controls dynein localization via a mechanism distinct from that of either BICD2 or CENP-F. We present a model in which ASUN promotes perinuclear enrichment of dynein at G2/M that facilitates BICD2- and CENP-F-mediated anchoring of dynein to nuclear pore complexes.
LPIAT1 regulates arachidonic acid content in phosphatidylinositol and is required for cortical lamination in mice
Authors: Lee Hyeon-Cheol , Inoue Takao , Sasaki Junko , Kubo Takuya , Matsuda Shinji , Nakasaki Yasuko , Hattori Mitsuharu , Tanaka Fumiharu , Udagawa Osamu , Kono Nozomu , Itoh Toshiki , Ogiso Hideo , Taguchi Ryo , Arita Makoto , Sasaki Takehiko , Arai Hiroyuki
Published: October 2012

Dietary arachidonic acid (AA) has roles in growth, neuronal development, and cognitive function in infants. AA is remarkably enriched in phosphatidylinositol (PI), an important constituent of biological membranes in mammals; however, the physiological significance of AA-containing PI remains unknown. In an RNA interference–based genetic screen using Caenorhabditis elegans, we recently cloned mboa-7 as an acyltransferase that selectively incorporates AA into PI. Here we show that lysophosphatidylinositol acyltransferase 1 (LPIAT1, also known as MBOAT7), the closest mammalian homologue, plays a crucial role in brain development in mice. Lpiat1−/−mice show almost no LPIAT activity with arachidonoyl-CoA as an acyl donor and show reduced AA contents in PI and PI phosphates. Lpiat1−/−mice die within a month and show atrophy of the cerebral cortex and hippocampus. Immunohistochemical analysis reveals disordered cortical lamination and delayed neuronal migration in the cortex of E18.5 Lpiat1−/−mice. LPIAT1 deficiency also causes disordered neuronal processes in the cortex and reduced neurite outgrowth in vitro. Taken together, these results demonstrate that AA-containing PI/PI phosphates play an important role in normal cortical lamination during brain development in mice.
Implications of M Bias in Epidemiologic Studies: A Simulation Study
Authors: Liu Wei , Brookhart M. Alan , Schneeweiss Sebastian , Mi Xiaojuan , Setoguchi Soko
Published: October 2012

Collider-stratification bias arises from conditioning on a variable (collider) which opens a path from exposure to outcome. M bias occurs when the collider-stratification bias is transmitted through ancestors of exposure and outcome. Previous theoretical work, but not empirical data, has demonstrated that M bias is smaller than confounding bias. The authors simulated data for large cohort studies with binary exposure, an outcome, a collider, and 2 predictors of the collider. They created 178 scenarios by changing the frequencies of variables and/or the magnitudes of associations among the variables. They calculated the effect estimate, percentage bias, and mean squared error. M bias in these realistic scenarios ranged from −2% to −5%. When the authors increased one or both relative risks for the relation between the collider and unmeasured factors to ≥8, the negative bias was more substantial (>15%). The result was substantially biased (e.g., >20%) if an unmeasured confounder that was also a collider was not adjusted to avoid M bias. In scenarios resembling those the authors examined, M bias had a small impact unless associations between the collider and unmeasured confounders were very large (relative risk > 8). When a collider is itself an important confounder, controlling for confounding would take precedence over avoiding M bias.
Sildenafil in Heart Failure (SilHF). An investigator‐initiated multinational randomized controlled clinical trial: rationale and design
Authors: Cooper Trond J. , Guazzi Marco , Al‐Mohammad Abdallah , Amir Offer , Bengal Tuvia , Cleland John G. , Dickstein Kenneth
Published: October 2012

Aims

Heart failure (HF) is a major clinical problem and, despite advances in both pharmacological and device therapy, the mortality remains high and quality of life poor. Over the last decade there has been growing interest in using phosphodiesterase‐5 (PDE‐5) inhibitors in HF associated with group 2 pulmonary hypertension (PH), with benefits reported on pulmonary haemodynamic and functional status in single‐centre trials

Methods

The Sildenafil in Heart Failure (SilHF) trial is a randomized, placebo‐controlled multinational trial designed to assess efficacy and tolerability of PDE‐5 inhibition with sildenafil (target dose 40 mg three times per day) in 210 patients with HF, New York Heart Association (NYHA) functional class II or III, and evidence of group 2 PH. The co‐primary endpoints are patient global assessment and the 6 min walk test. Secondary endpoints include NYHA functional class and the quality of life tools Euro QoL 5D and the Kansas City questionnaire. Patients will be followed up for 6 months.

Perspective

The authors hypothesize that PDE‐5 inhibition can improve exercise capacity and symptoms with acceptable tolerability in patients with HF and group 2 PH