bluuebunny/crossref_metadata_2025 huggingface dataset:
MAPK/JNK signalling: a potential autophagy regulation pathway
Authors: Zhou Yuan-Yuan , Li Ying , Jiang Wei-Qin , Zhou Lin-Fu
Published: April 2015

Autophagy refers to a lysosomal degradative pathway or a process of self-cannibalization. This pathway maintains nutrients levels for vital cellular functions during periods of starvation and it provides cells with survival advantages under various stress situations. However, the mechanisms responsible for the induction and regulation of autophagy are poorly understood. The c-Jun NH2-terminal kinase (JNK) signal transduction pathway functions to induce defence mechanisms that protect organisms against acute oxidative and xenobiotic insults. This pathway has also been repeatedly linked to the molecular events involved in autophagy regulation. The present review will focus on recent advances in understanding of the relationship between mitogen-activated protein kinase (MAPK)/JNK signalling and autophagic cell death.
Primary user localisation and uplink resource allocation in orthogonal frequency division multiple access cognitive radio systems
Authors: Nam Haewoon , Saeed Nasir , Ben‐Ghorbel Mand , Alouini Mohamed Slim
Published: April 2015

In cognitive radio networks, secondary users (SUs) can share spectrum with primary users (PUs) under the condition that no interference is caused to the PUs. To evaluate the interference imposed to the PUs, the cognitive systems discussed in the literature usually assume that the channel state information (CSI) of the link from a secondary transmitter to a primary receiver (interference link) is known at the secondary transmitter. However, this assumption may often be impractical in cognitive radio systems, since the PUs need to be oblivious to the presence of the SUs. The authors first discuss PU localisation and then introduce an uplink resource allocation algorithm for orthogonal frequency division multiple access‐based cognitive radio systems, where relative location information between primary and SUs is used instead of CSI of the interference link to estimate the interference. Numerical and simulation results show that it is indeed effective to use location information as a part of resource allocation and thus a near‐optimal capacity is achieved.
Trajectory‐based anomalous behaviour detection for intelligent traffic surveillance
Authors: Cai Yingfeng , Wang Hai , Chen Xiaobo , Jiang Haobin
Published: April 2015

This study proposes an efficient anomalous behaviour detection framework using trajectory analysis. Such framework includes the trajectory pattern learning module and the online abnormal detection module. In the pattern learning module, a coarse‐to‐fine clustering strategy is utilised. Vehicle trajectories are coarsely grouped into coherent clusters according to the main flow direction (MFD) vectors followed by a three‐stage filtering algorithm. Then a robust K ‐means clustering algorithm is used in each coarse cluster to get fine classification by which the outliers are distinguished. Finally, the hidden Markov model (HMM) is used to establish the path pattern within each cluster. In the online detection module, the new vehicle trajectory is compared against all the MFD distributions and the HMMs so that the coherence with common motion patterns can be evaluated. Besides that, a real‐time abnormal detection method is proposed. The abnormal behaviour can be detected when happening. Experimental results illustrate that the detection rate of the proposed algorithm is close to the state‐of‐the‐art abnormal event detection systems. In addition, the proposed system provides the lowest false detection rate among selected methods. It is suitable for intelligent surveillance applications.
Miniaturised printed elliptical nested fractal multiband antenna for energy harvesting applications
Authors: Taghadosi Mansour , Albasha Lutfi , Qaddoumi Nasser , Ali Mai
Published: April 2015

This study presents the design, optimisation, simulation and fabrication of a novel printed elliptical nested fractal (planar) antenna for multiband operation. The proposed antenna is intended to function as the receptor element in radio‐frequency energy harvesting applications. The simple microstrip structure and the compact size of the antenna ease its fabrication and allow it to be integrated with other electronic circuitry. It consists of nested elliptical structures fed by 50 Ω microstrip line with complementary elliptical ground along with rectangular ground plane. The added Hilbert structures at both sides of the antenna feeding line on the top layer enhance its performance to operate in multi‐frequency bands. This antenna exhibits good radiation and reflection characteristics at 910 MHz (global system of mobile (GSM 900)), 2.4 GHz (Bluetooth/wireless local area network), 3.2 GHz (Radiolocation, third generation (3G)), 3.8 GHz (for long‐term evolution, 4G) and additional 5 GHz band (wireless fidelity signals). The overall dimension of antenna is 41 mm (width) × 44 mm (length) × 1.778 mm (thickness). To the best knowledge of the authors, this is the widest bandwidth antenna to be developed at these small dimensions covering major standards from 900 MHz up to 6 GHz for electromagnetic energy harvesting applications.
Investigation on phonon scattering in a GaAs nanowire field effect transistor using the non-equilibrium Green's function formalism
Authors: Price A. , Martinez A.
Published: April 2015

Using quantum transport simulations, the impact of electron-phonon scattering on the transfer characteristic of a gate-all-around nanowire (GaAs) field effect transistor (NWFET) has been thoroughly investigated. The Non-Equilibrium Green's Function formalism in the effective mass approximation using a decoupled mode decomposition has been deployed. NWFETs of different dimensions have been considered, and scattering mechanisms including acoustic, optical and polar optical phonons have been included. The effective masses were extracted from tight binding simulations. High and low drain bias have been considered. We found substantial source to drain tunnelling current and significant impact of phonon scattering on the performance of the NWFET. At low drain bias, for a 2.2 × 2.2 nm2 cross-section transistor, scattering caused a 72%, 77%, and 81% decrease in the on-current for a 6 nm, 10 nm, and 20 nm channel length, respectively. This reduction in the current due to scattering is influenced by the increase in the tunnelling current. We include the percentage tunnelling for each valley at low and high drain bias. It was also found that the strong quantisation caused the relative position of the valleys to vary with the cross-section. This had a large effect on the overall tunnelling current. The phonon-limited mobility was also calculated, finding a mobility of 950 cm2/V s at an inversion charge density of 1012 cm−2 for a 4.2 × 4.2 nm2 cross-section device.
Carrier transfer in vertically stacked quantum ring-quantum dot chains
Authors: Mazur Yu. I. , Lopes-Oliveira V. , de Souza L. D. , Lopez-Richard V. , Teodoro M. D. , Dorogan V. G. , Benamara M. , Wu J. , Tarasov G. G. , Marega E. , Wang Z. M. , Marques G. E. , Salamo G. J.
Published: April 2015

The interplay between structural properties and charge transfer in self-assembled quantum ring (QR) chains grown by molecular beam epitaxy on top of an InGaAs/GaAs quantum dot (QD) superlattice template is analyzed and characterized. The QDs and QRs are vertically stacked and laterally coupled as well as aligned within each layer due to the strain field distributions that governs the ordering. The strong interdot coupling influences the carrier transfer both along as well as between chains in the ring layer and dot template structures. A qualitative contrast between different dynamic models has been developed. By combining temperature and excitation intensity effects, the tuning of the photoluminescence gain for either the QR or the QD mode is attained. The information obtained here about relaxation parameters, energy scheme, interlayer and interdot coupling resulting in creation of 1D structures is very important for the usage of such specific QR–QD systems for applied purposes such as lasing, detection, and energy-harvesting technology of future solar panels.
Analysis and design of nonlocal spin devices with electric-field-induced spin-transport acceleration
Authors: Takamura Yota , Akushichi Taiju , Shuto Yusuke , Sugahara Satoshi
Published: April 2015

We apply electric-field-induced acceleration for spin transport to a four-terminal nonlocal device and theoretically analyze its Hanle-effect signals. The effect of the ferromagnetic contact widths of the spin injector and detector on the signals is carefully discussed. Although Hanle-effect signals are randomized owing to the effect of the contact widths, this can be excluded by selecting an appropriate electric field for acceleration of spin transport. Spin lifetime can be correctly extracted by nonlocal devices with electric-field acceleration even using the spin injector and detector with finite contact widths.
Enhancement of Curie temperature in Mn2RuSn by Co substitution
Authors: Nelson A. , Kharel P. , Huh Y. , Fuglsby R. , Guenther J. , Zhang W. , Staten B. , Lukashev P. , Valloppilly S. , Sellmyer D. J.
Published: April 2015

The Co-substituted Mn2RuSn nanomaterials, namely, Mn2Ru0.5Co0.5Sn and Mn2Ru0.35Co0.65Sn have been synthesized and investigated. The presence of Co in the Mn2RuSn (a = 6.21 Å) decreased the lattice parameter, where a = 6.14 Å and 6.12 Å for the as prepared Mn2Ru0.5Co0.5Sn and Mn2Ru0.35Co0.65Sn, respectively. The samples show a ferrimagnetic spin order with relatively small coercivities, similar to those of soft magnetic materials. There is a substantial increase in the Curie temperature (Tc = 448 K for Mn2Ru0.5Co0.5Sn and 506 K for Mn2Ru0.35Co0.65Sn) of Mn2RuSn (Tc = 272.1 K) due to Co substitution, which is a result of strengthening of the positive exchange interaction in this material. These materials are highly stable against heat treatment of up to 450 °C. The first-principles calculations are consistent with our experimentally observed structural and magnetic properties. They also provide insight on how the magnetic and electronic structures change when Ru is replaced with Co in Mn2RuSn.
Controlling the size and relaxation dynamics of superferromagnetic domains
Authors: Chowdhury N. , Bedanta S. , Sing S. , Kleemann W.
Published: April 2015

The magnetization reversal process has been studied on a discontinuous metal-insulator multilayer sample [Co80Fe20(1.3 nm)/Al2O3(3 nm)]10 showing superferromagnetic (SFM) behavior. Size and shape of SFM domains can be changed by varying the angle θ between the magnetic field and the easy axis (EA). The magnetization reversal process along the EA is governed by domain wall motion. However, upon approaching the hard axis at increasing θ coherent rotation of superspins becomes dominant in the magnetization reversal process. This leads to the reduction of domain sizes for larger values of θ. The relaxation of magnetization has also been studied for various values of θ. We find fast relaxation along the easy axis, while the relaxation time increases for increasing θ. In general, the angular dependence of the magnetization reversal of SFM domains shows properties similar to continuous thin films.
Comparative analysis of scintillation characteristics derived from different emission mechanisms in BaCl2
Authors: Fukabori Akihiro
Published: April 2015

Crack-free La3+-substituted BaCl2 single crystals without and with Eu2+ as an activator were successfully grown using the micro-pulling-down method. Luminescence bands from BaCl2 without and with the Eu2+ activator were assigned as mainly intrinsic and extrinsic, respectively. Therefore, BaCl2 as a host material is suitable for investigating the effects of the emission mechanism on the non-proportionality curves and energy resolution plots. First, the scintillation characteristics of BaCl2:La3+(11 at. %) and BaCl2:La3+(7.7 at. %):Eu2+(0.5 at. %) single crystals were determined along with those of BaCl2 and BaCl2:Eu2+(0.5 at. %) crystals. Second, the non-proportionality curves from the different emission origins in BaCl2 were confirmed to be consistent with phenomenological models. Third, the non-proportionality curves and energy resolution plots originating from intrinsic (without Eu2+) and extrinsic (with Eu2+) luminescence were compared. The results experimentally demonstrated that the emission mechanism influenced scintillator non-proportionality curves.
Soft mode characteristics of up-up-down-down spin chains: The role of exchange interactions on lattice dynamics
Authors: Guo Y. J. , Gao Y. J. , Ge C. N , Guo Y. Y. , Yan Z. B. , Liu J.-M.
Published: April 2015

In this work, the dynamics of a diatomic chain is investigated with ↑↑↓↓ spin order in which the dispersion relation characterizes the effect of magnetic interactions on the lattice dynamics. The optical or acoustic mode softening in the center or boundary of the Brillouin zone can be observed, indicating the transitions of ferroelectric state, antiferromagnetic state, or ferroelastic state. The coexistence of the multiferroic orders related to the ↑↑↓↓ spin order represents a type of intrinsic multiferroic with strong ferroelectric order and different microscopic mechanisms.
Thermal relaxation in magnetic multi-layer materials with mixed hysteretic behavior
Authors: Dimian M. , Andrei P. , Mehta M. , Idubor O. A.
Published: April 2015

Thermal relaxation phenomena in mixed-type hysteretic systems are investigated by using recently developed mixed Preisach model and Monte Carlo technique. The anomalous hysteretic behavior observed in several heterogeneous materials, especially in nanoscale embedding, is also generating unconventional relaxation processes which may involve several steps before relaxing to the anhysteretic state. The medium-term relaxation behavior is studied under various noisy environments and applied magnetic fields, analyzing the influence of noise strength, noise bandwidth, and field values on the relaxation characteristics.
Dissipative time-dependent quantum transport theory: Quantum interference and phonon induced decoherence dynamics
Authors: Zhang Yu , Yam ChiYung , Chen GuanHua
Published: April 2015

A time-dependent inelastic electron transport theory for strong electron-phonon interaction is established via the equations of motion method combined with the small polaron transformation. In this work, the dissipation via electron-phonon coupling is taken into account in the strong coupling regime, which validates the small polaron transformation. The corresponding equations of motion are developed, which are used to study the quantum interference effect and phonon-induced decoherence dynamics in molecular junctions. Numerical studies show clearly quantum interference effect of the transport electrons through two quasi-degenerate states with different couplings to the leads. We also found that the quantum interference can be suppressed by the electron-phonon interaction where the phase coherence is destroyed by phonon scattering. This indicates the importance of electron-phonon interaction in systems with prominent quantum interference effect.
Impact of symmetry on the ferroelectric properties of CaTiO3 thin films
Authors: Biegalski Michael D. , Qiao Liang , Gu Yijia , Mehta Apurva , He Qian , Takamura Yayoi , Borisevich Albina , Chen Long-Qing
Published: April 2015

Epitaxial strain is a powerful tool to induce functional properties such as ferroelectricity in thin films of materials that do not possess ferroelectricity in bulk form. In this work, a ferroelectric state was stabilized in thin films of the incipient ferroelectric, CaTiO3, through the careful control of the biaxial strain state and TiO6 octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO3 films grown on La0.18Sr0.82Al0.59Ta0.41O3 (LSAT) and NdGaO3 (NGO) substrates experienced a 1.1% biaxial strain state but differed in their octahedral tilt structures. A suppression of the out-of-plane rotations of the TiO6 octahedral in films grown on LSAT substrates resulted in a robust ferroelectric I4 mm phase with remnant polarization ∼5 μC/cm2 at 10 K and Tc near 140 K. In contrast, films grown on NGO substrates with significant octahedral tilting showed reduced polarization and Tc. These results highlight the key role played by symmetry in controlling the ferroelectric properties of perovskite oxide thin films.
Stress-induced anomalous shift of optical band gap in Ga-doped ZnO thin films: Experimental and first-principles study
Authors: Wang Yaqin , Tang Wu , Liu Jie , Zhang Lan
Published: April 2015

In this work, highly c-axis oriented Ga-doped ZnO thin films have been deposited on glass substrates by RF magnetron sputtering under different sputtering times. The optical band gap is observed to shift linearly with the electron concentration and in-plane stress. The failure of fitting the shift of band gap as a function of electron concentration using the available theoretical models suggests the in-plane stress, instead of the electron concentration, be regarded as the dominant cause to this anomalous redshift of the optical band gap. And the mechanism of stress-dependent optical band gap is supported by the first-principles calculation based on density functional theory.
Thermal tuning of infrared resonant absorbers based on hybrid gold-VO2 nanostructures
Authors: Kocer Hasan , Butun Serkan , Banar Berker , Wang Kevin , Tongay Sefaatttin , Wu Junqiao , Aydin Koray
Published: April 2015

Resonant absorbers based on plasmonic materials, metamaterials, and thin films enable spectrally selective absorption filters, where absorption is maximized at the resonance wavelength. By controlling the geometrical parameters of nano/microstructures and materials' refractive indices, resonant absorbers are designed to operate at wide range of wavelengths for applications including absorption filters, thermal emitters, thermophotovoltaic devices, and sensors. However, once resonant absorbers are fabricated, it is rather challenging to control and tune the spectral absorption response. Here, we propose and demonstrate thermally tunable infrared resonant absorbers using hybrid gold-vanadium dioxide (VO2) nanostructure arrays. Absorption intensity is tuned from 90% to 20% and 96% to 32% using hybrid gold-VO2 nanowire and nanodisc arrays, respectively, by heating up the absorbers above the phase transition temperature of VO2 (68 °C). Phase change materials such as VO2 deliver useful means of altering optical properties as a function of temperature. Absorbers with tunable spectral response can find applications in sensor and detector applications, in which external stimulus such as heat, electrical signal, or light results in a change in the absorption spectrum and intensity.
Static and high frequency magnetic properties of FeGa thin films deposited on convex flexible substrates
Authors: Yu Ying , Zhan Qingfeng , Wei Jinwu , Wang Jianbo , Dai Guohong , Zuo Zhenghu , Zhang Xiaoshan , Liu Yiwei , Yang Huali , Zhang Yao , Xie Shuhong , Wang Baomin , Li Run-Wei
Published: April 2015

Magnetostrictive FeGa thin films were deposited on the bowed flexible polyethylene terephthalate (PET) substrates, which were fixed on the convex mold. A compressive stress was induced in FeGa films when the PET substrates were shaped from convex to flat. Due to the effect of magnetostriction, FeGa films exhibit an obvious in-plane uniaxial magnetic anisotropy which could be enhanced by increasing the applied pre-strains on the substrates during growth. Consequently, the ferromagnetic resonance frequency of the films was significantly increased, but the corresponding initial permeability was decreased. Moreover, the films with pre-strains less than 0.78% exhibit a working bandwidth of microwave absorption about 2 GHz. Our investigations demonstrated a convenient method via the pre-strained substrates to tune the high frequency properties of magnetic thin films which could be applied in flexible microwave devices.
Numerical study of the S809 airfoil aerodynamic performance using a co-flow jet active control concept
Authors: Xu He-Yong , Xing Shi-Long , Ye Zheng-Yin
Published: April 2015

A Co-Flow Jet (CFJ) active flow control concept is implemented on the S809 airfoil and numerically investigated by using an in-house code based on Reynolds-averaged Navier-Stokes equations and the Spalart-Allmaras turbulence model, aiming to systematically study the jet effect on the airfoil aerodynamic performance. The solver is validated by comparing the computed results with the baseline experiment measurement. The calculated aerodynamic force and moment coefficients agree fairly well with the experimental data, demonstrating the present solver can predict the attached as well as separated flows around the S809 airfoil with an acceptable precision. The CFJ jet-off geometry of S809 airfoil is simulated to study the jet channel effect on the baseline aerodynamic characteristic, showing that the jet channel could reduce the lift, increase the drag and cause an earlier abrupt stall at angle of attack (AoA) 16.24°. The CFJ jet-on geometry is elaborately studied at three jet momentum coefficient levels, showing that co-flow jet has a significantly positive effect in increasing lift, stall margin, and drag reduction. For the cases with jet momentum coefficients 0.12 and 0.18, the total drag even becomes negative. It is found that the drag from pressure and shear stress of CFJ airfoil is larger than that of baseline, and it is the negative mass-flow-produced drag that significantly reduces the total drag to be below zero. For cases in which AoA are below a critical value (e.g., 20.15° for the case with jet momentum coefficient 0.18), the power required to drive the jet flow decreases when AoA increases, demonstrating that the CFJ concept has an attractive advantage of minimum energy consuming. The present CFJ concept is proved to be a promising and effective active flow control method in the wind turbine application.
Formation of lipid bilayer membrane in a poly(dimethylsiloxane) microchip integrated with a stacked polycarbonate membrane support and an on-site nanoinjector
Authors: Teng Wei , Ban Changill , Hahn Jong Hoon
Published: April 2015

This paper describes a new and facile approach for the formation of pore-spanning bilayer lipid membranes (BLMs) within a poly(dimethylsiloxane) (PDMS) microfluidic device. Commercially, readily available polycarbonate (PC) membranes are employed for the support of BLMs. PC sheets with 5 μm, 2 μm, and 0.4 μm pore diameters, respectively, are thermally bonded into a multilayer-stack, reducing the pore density of 0.4 μm-pore PC by a factor of 200. The BLMs on this support are considerably stable (a mean lifetime: 17 h). This multilayer-stack PC (MSPC) membrane is integrated into the PDMS chip by an epoxy bonding method developed to secure durable bonding under the use of organic solvents. The microchip has a special channel for guiding a micropipette in the proximity of the MSPC support. With this on-site injection technique, tens to hundreds of nanoliters of solutions can be directly dispensed to the support. Incorporating gramicidin ion channels into BLMs on the MSPC support has confirmed the formation of single BLMs, which is based on the observation from current signals of 20 pS conductance that is typical to single channel opening. Based on the bilayer capacitance (1.4 pF), about 15% of through pores across the MSPC membrane are estimated to be covered with BLMs.
The analysis on the impact of the roof angle on electricity energy generation of photovoltaic panels in Kahramanmaras, Turkey—A case study for all seasons
Authors: Yilmaz Saban , Ozcalik Hasan Riza , Dincer Furkan
Published: April 2015

Photovoltaic (PV) panels absorb solar energy most when solar radiation perpendicularly reaches on upon surface. This leads to the notion of optimal roof angle. Optical and geometrical properties of the panels are of vital importance in order to obtain maximum energy from the Sun. Therefore, this study focuses on the horizontal roof angle which has a crucial impact on the performance of PV panels. Total solar radiation, optimal roof angle and effects of different angles on PV panels in Kahramanmaras province of Turkey on different days are numerically and experimentally analyzed and discussed. Additionally, roof angle influences the amount of solar radiation reaching on the surface and varies depending on the geographic location and seasons. 7.9% more energy can be generated in the proposed systems where roof angle can be daily adjusted. This greatly influences the amount of solar energy when optimal roof angles are calculated annually depending on the seasons in a region. However, it is quite costly and challenging to adjust the roof angle as far as a building is concerned.
Enhancement of two dimensional electron gas concentrations due to Si3N4 passivation on Al0.3Ga0.7N/GaN heterostructure: strain and interface capacitance analysis
Authors: Dinara Syed Mukulika , Jana Sanjay Kr. , Ghosh Saptarsi , Mukhopadhyay Partha , Kumar Rahul , Chakraborty Apurba , Bhattacharya Sekhar , Biswas Dhrubes
Published: April 2015

Enhancement of two dimensional electron gas (2DEG) concentrations at Al0.3Ga0.7N/GaN hetero interface after a-Si3N4 (SiN) passivation has been investigated from non-destructive High Resolution X-ray Diffraction (HRXRD) analysis, depletion depth and capacitance-voltage (C-V) profile measurement. The crystalline quality and strained in-plane lattice parameters of Al0.3Ga0.7N and GaN were evaluated from double axis (002) symmetric (ω-2θ) diffraction scan and double axis (105) asymmetric reciprocal space mapping (DA RSM) which revealed that the tensile strain of the Al0.3Ga0.7N layer increased by 15.6% after SiN passivation. In accordance with the predictions from theoretical solution of Schrödinger-Poisson’s equations, both electrochemical capacitance voltage (ECV) depletion depth profile and C-V characteristics analyses were performed which implied effective 9.5% increase in 2DEG carrier density after passivation. The enhancement of polarization charges results from increased tensile strain in the Al0.3Ga0.7N layer and also due to the decreased surface states at the interface of SiN/Al0.3Ga0.7N layer, effectively improving the carrier confinement at the interface.
Determination of band offsets at the Al:ZnO/Cu2SnS3 interface using X-ray photoelectron spectroscopy
Authors: Dias Sandra , Krupanidhi S. B.
Published: April 2015

The Al:ZnO/Cu2SnS3 semiconductor heterojunction was fabricated. The structural and optical properties of the semiconductor materials were studied. The band offset at the Al:ZnO/Cu2SnS3 heterojunction was studied using X-ray photoelectron spectroscopy technique. From the measurement of the core level energies and valence band maximum of the constituent elements, the valence band offset was calculated to be −1.1 ± 0.24 eV and the conduction band offset was 0.9 ± 0.34 eV. The band alignment at the heterojunction was found to be of type-I. The study of Al:ZnO/Cu2SnS3 heterojunction is useful for solar cell applications.
Increasing the proportion of female lambs by feeding Merino ewes a diet high in omega-6 fatty acids around mating
Authors: Clayton E. H. , Friend M. A. , Wilkins J. F.
Published: April 2015

In previous experiments, the proportion of female lambs was higher when BL × Merino ewes were offered a diet high in omega-6 (n-6) than when offered one low in n-6 around joining. The aim of the current study was to determine whether the proportion of female lambs increases when Merino ewes are fed a diet high in n-6 and to further test the effect of time of feeding relative to mating. Ewes were fed a low n-6 (ryegrass silage) or high n-6 (oats and cottonseed meal) diet for ~40 days pre-mating or 40 days pre- and 17 days post-mating. Liveweight, fat score, plasma fatty acid status and lamb sex were determined. The concentration of plasma n-6 was higher (P < 0.001) and the time to oestrus shorter (P < 0.001) when ewes received the high n-6 compared with the low n-6 diet. The proportion of female lambs was higher when ewes were fed the high n-6 compared with the low n-6 diet either pre-mating only (71.3% vs 48.7%, P = 0.017) or both pre- and post-mating (69.6% vs 37.3%, P < 0.001). The sex ratio differed from an expected 50 : 50 when ewes were fed the high n-6 diet (P < 0.001), but not the low n-6 diet (P = 0.223). The effect of the high n-6 diet on the sex ratio of lambs in Merino ewes may act pre-conception, as the effect of the diet was not greater when ewes were fed both pre- and post-mating. Altering diet to increase female lamb proportions may be economically viable to producers of first-cross ewes.
Structure, floristics and diversity of tropical montane rain forests over ultramafic soils on Mount Kinabalu (Borneo) compared with those on non-ultramafic soils
Authors: Aiba Shin-ichiro , Sawada Yoshimi , Takyu Masaaki , Seino Tatsuyuki , Kitayama Kanehiro , Repin Rimi
Published: April 2015

We describe here the structure, floristics and diversity of tropical montane rain forests over ultramafic soils on Mount Kinabalu, Borneo, and compared them with those on non-ultramafic soils. We used 14 sample plots from 1580 to 3080 m elevation, six on ultramafic soils and eight on non-ultramafic soils, and identified all trees ≥4.8 cm diameter. The plot area ranged from 0.1 to 1 ha, the majority (nine plots) being 0.25 ha. Forests on ultramafic soils showed more stunted structure, especially at higher altitudes, than those on non-ultramafic soils and on ridges than on slopes. Species of Coniferae (Araucariaceae and Podocarpaceae) and Myrtaceae strongly dominated on ultramafic soils occupying 61–96% of basal area in each plot, compared with 22–63% on non-ultramafic soils. Among 287 species found in the 14 plots, only nine species (including four species endemic to Mount Kinabalu) were strictly restricted to ultramafic soils. Nonmetric multidimensional scaling demonstrated that elevational change in species composition was accelerated on ultramafic soils and on ridges. Tree species diversity was generally lower on ultramafic soils than on non-ultramafic soils at the comparative altitudes. Multiple regression analysis suggested that soil nutrients (phosphorus and nitrogen) could be the cause of vegetation differentiation between ultramafic and non-ultramafic soils, although the data on soil metals are lacking. Comparison of our results with those from other mountains with ultramafic soils in South-east Asia demonstrated the uniqueness of the montane rain forests over ultramafic soils on Mount Kinabalu.
Herbicide resistance in Bromus and Hordeum spp. in the Western Australian grain belt
Authors: Owen Mechelle J. , Martinez Neree J. , Powles Stephen B.
Published: April 2015

Random surveys conducted in the Western Australian (WA) grain belt have shown that herbicide-resistant Lolium rigidum and Raphanus raphanistrum are a widespread problem across the cropping region. In 2010, a random survey was conducted to establish the levels of herbicide resistance for common weed species in crop fields, including the minor but emerging weeds Bromus and Hordeum spp. This is the first random survey in WA to establish the frequency of herbicide resistance in these species. For the annual grass weed Bromus, 91 populations were collected, indicating that this species was present in >20% of fields. Nearly all populations were susceptible to the commonly used herbicides tested in this study; however, a small number of populations (13%) displayed resistance to the acetolactate synthase-inhibiting sulfonylurea herbicides. Only one population displayed resistance to the acetyl-coenzyme A carboxylase-inhibiting herbicides. Forty-seven Hordeum populations were collected from 10% of fields, with most populations being susceptible to all herbicides tested. Of the Hordeum populations, 8% were resistant to the sulfonylurea herbicide sulfosulfuron, some with cross-resistance to the imidazolinone herbicides. No resistance was found to glyphosate or paraquat, although resistance to these herbicides has been documented elsewhere in Australia for Hordeum spp. (Victoria) and Bromus spp. (Victoria, South Australia and WA).
Significant genetic structure despite high vagility revealed through mitochondrial phylogeography of an Australian freshwater turtle (Chelodina longicollis)
Authors: Hodges K. , Donnellan S. , Georges A.
Published: April 2015

Restriction to the freshwater environment plays a dominant role in the population genetic structure of freshwater fauna. In taxa with adaptations for terrestriality, however, the restrictions on dispersal imposed by drainage divides may be overcome. We investigate the mitochondrial phylogeographic structure of the eastern long-necked turtle (Chelodina longicollis), a widespread Australian freshwater obligate with strong overland dispersa\l capacity and specific adaptations to terrestriality. We predict that such characteristics make this freshwater species a strong candidate to test how life-history traits can drive gene flow and interbasin connectivity, overriding the constraining effects imposed by hydrological boundaries. Contrary to expectations, and similar to low-vagility freshwater vertebrates, we found two ancient mitochondrial haplogroups with clear east–west geographic partitioning either side of the Great Dividing Range. Each haplogroup is characterised by complex genetic structure, demographically stable subpopulations, and signals of isolation by distance. This pattern is overlaid with signatures of recent gene flow, likely facilitated by late Pleistocene and ongoing anthropogenic landscape change. We demonstrate that the divergent effects of landscape history can overwhelm the homogenising effects of life-history traits that connect populations, even in a highly vagile species.
Figure-ground modulation in awake primate thalamus
Authors: Jones Helen E. , Andolina Ian M. , Shipp Stewart D. , Adams Daniel L. , Cudeiro Javier , Salt Thomas E. , Sillito Adam M.
Published: April 2015

Significance

Perceptually, the visual cortical areas are considered to reconstruct objects from the diverse components of early distributed processing by grouping image elements and segregating them from the background as a figure. An assumption here is that raw, essentially unchanged information from the visual thalamus provides the basic pattern essential for the operation of these higher-level abstractions. However, here we demonstrate strong enhancement of neuronal firing to the figure component of a figure-ground stimulus in recordings from the visual thalamus of behaving primates. This suggests the signature of a higher-order percept is introduced into the thalamus in a reentrant manner via the corticofugal feedback connections and causes our visual input to confirm what we think we are seeing.
Implausibility of the vibrational theory of olfaction
Authors: Block Eric , Jang Seogjoo , Matsunami Hiroaki , Sekharan Sivakumar , Dethier Bérénice , Ertem Mehmed Z. , Gundala Sivaji , Pan Yi , Li Shengju , Li Zhen , Lodge Stephene N. , Ozbil Mehmet , Jiang Huihong , Penalba Sonia F. , Batista Victor S. , Zhuang Hanyi
Published: April 2015

Significance

The vibrational theory of olfaction posits detection of odorants through their vibrational frequencies rather than solely through “hand-in-glove” substrate/enzyme-like odorant–odorant receptor (OR) interactions. To test the theory, we compare responses of different human and mouse ORs toward deuterated and undeuterated isotopomers (isotopic atom isomers) of receptor-responsive odorants because isotopomers should differ in their molecular vibrational frequencies. However, no differences in receptor response are seen with any tested labeled/unlabeled odorant/receptor pairs. Because published behavioral studies have shown that humans can distinguish isotopomers, perireceptor events or impurities, rather than receptor-level vibrational effects, are suggested. Because theoretical aspects of the vibration theory are also found wanting, the vibration theory is deemed implausible in the absence of compelling receptor-level experimental evidence to the contrary.
Effect of Exhaustive Exercise on the Swimming Capability and Metabolism of Juvenile Siberian Sturgeon
Authors: Cai L. , Johnson D. , Mandal P. , Gan M. , Yuan X. , Tu Z. , Huang Y.
Published: April 2015

This study investigated the effect of exhaustive exercise on the swimming performance of Siberian Sturgeon Acipenser baeri and on the time required for recovery. Critical swimming speed (Ucrit), maximum metabolic rate (MMR), speed coefficient (c), and excess postexercise oxygen consumption (EPOC) were measured on three groups of juvenile sturgeon by stepped velocity tests at 20°C in a fish respirometer. After a recovery period of 1 h (group 1), 1 d (group 2), or 1 week (group 3), the four parameters were determined a second time and the results compared. The Ucrit of the sturgeon was 3.26 ± 0.11 body lengths per second (mean ± SE). After a 1 h recovery period, Ucrit was 78% of its initial value and complete recovery required slightly more than 1 d. Recovery of MMR followed the same pattern. The speed exponent (c) was approximately 1.0, indicating that the Siberian Sturgeon is an efficient swimmer; swimming efficiency decreased after exhaustive exercise and the effect appeared to last for at least 1 week. Exhaustive exercise strongly hindered anaerobic swimming in Siberian Sturgeon for more than an hour.
Infested stored crops in the Iron Age I granary at Tel Hadar
Authors: Kislev Mordechai E.
Published: April 2015

Large quantities of charred seeds of field crops were found in a granary at early Iron Age (end of the eleventh century BCE) Tel Hadar, located at the eastern shore of the Sea of Galilee, Israel. They include mainly local naked wheat (Triticum parvicoccum), as well as bitter vetch (Vicia ervilia) and chickpea (Cicer arietinum) seeds. While the wheat was heavily infested by two major storage pest beetles – granary weevil (Sitophilus granarius) and a newcomer, the lesser grain borer (Rhyzopertha dominica) – the two pulses were much less infested. The presence of a large number of adults and larvae ofR.dominicasuggests that the granary was burned in mid or late summer. Seeds of the weedLolium temulentumand several other weeds were also found.
ATR and a Chk1-Aurora B pathway coordinate postmitotic genome surveillance with cytokinetic abscission
Authors: Mackay Douglas R. , Ullman Katharine S.
Published: April 2015

Aurora B regulates cytokinesis timing and plays a central role in the abscission checkpoint. Cellular events monitored by this checkpoint are beginning to be elucidated, yet signaling pathways upstream of Aurora B in this context remain poorly understood. Here we reveal a new connection between postmitotic genome surveillance and cytokinetic abscission. Underreplicated DNA lesions are known to be transmitted through mitosis and protected in newly formed nuclei by recruitment of 53BP1 and other proteins until repair takes place. We find that this genome surveillance initiates before completion of cytokinesis. Elevating replication stress increases this postmitotic process and delays cytokinetic abscission by keeping the abscission checkpoint active. We further find that ATR activity in midbody-stage cells links postmitotic genome surveillance to abscission timing and that Chk1 integrates this and other signals upstream of Aurora B to regulate when the final step in the physical separation of daughter cells occurs.
The Role of Dendritic Signaling in the Anesthetic Suppression of Consciousness
Authors: Meyer Kaspar
Published: April 2015

AbstractAbstract

Despite considerable progress in the identification of the molecular targets of general anesthetics, it remains unclear how these drugs affect the brain at the systems level to suppress consciousness. According to recent proposals, anesthetics may achieve this feat by interfering with corticocortical top–down processes, that is, by interrupting information flow from association to early sensory cortices. Such a view entails two immediate questions. First, at which anatomical site, and by virtue of which physiological mechanism, do anesthetics interfere with top–down signals? Second, why does a breakdown of top–down signaling cause unconsciousness? While an answer to the first question can be gleaned from emerging neurophysiological evidence on dendritic signaling in cortical pyramidal neurons, a response to the second is offered by increasingly popular theoretical frameworks that place the element of prediction at the heart of conscious perception.

General anesthetics suppress signal conduction along the apical dendrites of cortical pyramidal neurons. Thereby, they interfere with corticocortical top–down signals and cause a breakdown of the continuous predictive process that is core to conscious perception.
The Effect of Ptosis Surgery on Brow Position and the Utility of Preoperative Phenylephrine Testing
Authors: Rootman Daniel B. , Karlin Justin , Moore Grant , Goldberg Robert
Published: April 2015

Introduction:

Many reports have suggested that upper eyelid position and brow height can be interdependent; however, the relation is not universally observed. This study aims to understand the prevalence of this phenomenon and examine the utility of phenylephrine testing in predicting brow height change after surgery.

Methods:

Ptotic eyelids undergoing Muller’s muscle conjunctiva resection surgery in which phenylephrine testing was performed were included. The distance from both the center of the pupil to the upper eyelid and the lower brow margin were measured in the midpupillary line. Measurements were performed based on photographs taken on presentation, after phenylephrine testing and at postsurgical follow-up. Change in eyelid margin and brow position between each of these conditions was assessed. Associations between changes in eyelid margin and brow position were analyzed, and a receiver operating characteristic curve for brow change after phenylephrine instillation as a predictor of postoperative brow change was fit.

Results:

In the sample of 125 eyes, there was a significant change in mean marginal reflex distance one both with application of phenylephrine and after surgery (p < 0.05). There was no significant change in brow height with instillation of phenylephrine (p > 0.05). There was a significant change in brow height with surgery (1 mm; p < 0.05). Change in marginal reflex distance one with surgery or with phenylephrine was not significantly correlated with change in brow height after surgery (Pearson’s r = 0.06; p > 0.05). Brow height change with phenylephrine was significantly correlated with brow height change after surgery (p < 0.05). Clinically relevant brow height change was defined as mean change minus one standard deviation, for a total decrease of 3.8 mm. By this criterion, 13.6% patients (n = 17) demonstrated clinically relevant brow height change. These patients had a greater preoperative brow height (p < 0.05) and a greater response to phenylephrine (p < 0.05). Based on receiver operating characteristic analysis, a threshold change of 3.5 mm in brow height with phenylephrine had a sensitivity of 0.94, and specificity of 0.10 for postoperative brow height change.

Conclusions:

Approximately 15% of the population studied tends to have a significant change in brow position with ptosis surgery. Patients who do not demonstrate a reduction in brow height of at least 3.5 mm after phenylephrine instillation preoperatively are unlikely to have clinically relevant brow height reduction after surgery.
Meta-analysis Identifies Serum C-Reactive Protein as an Indicator of Atrial Fibrillation Risk After Coronary Artery Bypass Graft
Authors: Li Tong , Sun Ze-Lin , Xie Qi-Ying
Published: April 2015

A meta-analysis–based study was conducted to examine the clinical value of serum C-reactive protein (CRP) levels in predicting postoperative atrial fibrillation (POAF) in patients with coronary artery disease (CAD) who underwent coronary artery bypass graft. Computer-based search of scientific literature databases was performed to identify relevant studies in strict accordance with our inclusion and exclusion criteria. Data extracted from the selected studies were used to perform meta-analysis using the STATA 12.0 statistical software. Standardized mean differences (SMDs) with their 95% confidence interval (95% CI) were calculated. The database search strategy initially identified 62 articles (Chinese = 17, English = 45). After multiple levels of screening and validation, 15 case–control studies (Chinese = 1, English = 14), containing of a total of 3110 atrial fibrillation patients (POAF = 925, non-POAF = 2185), were selected for our meta-analysis. The meta-analysis results confirmed that serum CRP level was remarkably higher in patients with POAF compared with non-POAF (SMD = 1.36; 95% CI, 0.44–2.28; P = 0.004). Ethnicity-stratified analysis revealed that elevated serum CRP levels were associated with an increased risk of POAF in white patients with CAD (SMD = 0.85; 95% CI, 0.12–1.58; P = 0.022), but not Asian patients with CAD (SMD = 3.31, 95% CI, −0.04 to 6.66; P = 0.053). Elevated CRP levels, indicating profound inflammation, may be associated with significantly increased risk of POAF in patients with CAD who underwent coronary artery bypass graft. Thus, serum CRP levels are important for early diagnosis and monitoring of POAF in high-risk patients.
Travelling waves in the Holling–Tanner model with weak diffusion
Authors: Ghazaryan Anna , Manukian Vahagn , Schecter Stephen
Published: April 2015

For a wide range of parameters, we study travelling waves in a diffusive version of the Holling–Tanner predator–prey model from population dynamics. Fronts are constructed using geometric singular perturbation theory and the theory of rotated vector fields. We focus on the appearance of the fronts in various singular limits. In addition, periodic travelling waves of relaxation oscillation type are constructed using a recent generalization of the entry–exit function.
Unexpected evolutionary diversity in a recently extinct Caribbean mammal radiation
Authors: Brace Selina , Turvey Samuel T. , Weksler Marcelo , Hoogland Menno L. P. , Barnes Ian
Published: April 2015

Identifying general patterns of colonization and radiation in island faunas is often hindered by past human-caused extinctions. The insular Caribbean is one of the only complex oceanic-type island systems colonized by land mammals, but has witnessed the globally highest level of mammalian extinction during the Holocene. Using ancient DNA analysis, we reconstruct the evolutionary history of one of the Caribbean's now-extinct major mammal groups, the insular radiation of oryzomyine rice rats. Despite the significant problems of recovering DNA from prehistoric tropical archaeological material, it was possible to identify two discrete Late Miocene colonizations of the main Lesser Antillean island chain from mainland South America by oryzomyine lineages that were only distantly related. A high level of phylogenetic diversification was observed within oryzomyines across the Lesser Antilles, even between allopatric populations on the same island bank. The timing of oryzomyine colonization is closely similar to the age of several other Caribbean vertebrate taxa, suggesting that geomorphological conditions during the Late Miocene facilitated broadly simultaneous overwater waif dispersal of many South American lineages to the Lesser Antilles. These data provide an important baseline by which to further develop the Caribbean as a unique workshop for studying island evolution.