bluuebunny/crossref_metadata_2025 huggingface dataset:
Off-resonance energy absorption in a linear Paul trap due to mass selective resonant quenching
Authors: Sivarajah I. , Goodman D. S. , Wells J. E. , Narducci F. A. , Smith W. W.
Published: November 2013

Linear Paul traps (LPT) are used in many experimental studies such as mass spectrometry, atom-ion collisions, and ion-molecule reactions. Mass selective resonant quenching (MSRQ) is implemented in LPT either to identify a charged particle's mass or to remove unwanted ions from a controlled experimental environment. In the latter case, MSRQ can introduce undesired heating to co-trapped ions of different mass, whose secular motion is off resonance with the quenching ac field, which we call off-resonance energy absorption (OREA). We present simulations and experimental evidence that show that the OREA increases exponentially with the number of ions loaded into the trap and with the amplitude of the off-resonance external ac field.
Ionization photophysics and spectroscopy of dicyanoacetylene
Authors: Leach Sydney , Schwell Martin , Garcia Gustavo A. , Bénilan Yves , Fray Nicolas , Gazeau Marie-Claire , Gaie-Levrel François , Champion Norbert , Guillemin Jean-Claude
Published: November 2013

Photoionization of dicyanoacetylene was studied using synchrotron radiation over the excitation range 8–25 eV, with photoelectron-photoion coincidence techniques. The absolute ionization cross-section and detailed spectroscopic aspects of the parent ion were recorded. The adiabatic ionization energy of dicyanoacetylene was measured as 11.80 ± 0.01 eV. A detailed analysis of the cation spectroscopy involves new aspects and new assignments of the vibrational components to excitation of the quasi-degenerate A2Πg, B2Σg+ states as well as the C2Σu+ and D2Πu states of the cation. Some of the structured autoionization features observed in the 12.4–15 eV region of the total ion yield spectrum were assigned to vibrational components of valence shell transitions and to two previously unknown Rydberg series converging to the D2Πu state of C4N2+. The appearance energies of the fragment ions C4N+, C3N+, C4+, C2N+, and C2+ were measured and their heats of formation were determined and compared with existing literature values. Thermochemical calculations of the appearance potentials of these and other weaker ions were used to infer aspects of dissociative ionization pathways.
Spectral asymmetry of the massless Dirac operator on a 3-torus
Authors: Downes Robert J. , Levitin Michael , Vassiliev Dmitri
Published: November 2013

Consider the massless Dirac operator on a 3-torus equipped with Euclidean metric and standard spin structure. It is known that the eigenvalues can be calculated explicitly: the spectrum is symmetric about zero and zero itself is a double eigenvalue. The aim of the paper is to develop a perturbation theory for the eigenvalue with smallest modulus with respect to perturbations of the metric. Here the application of perturbation techniques is hindered by the fact that eigenvalues of the massless Dirac operator have even multiplicity, which is a consequence of this operator commuting with the antilinear operator of charge conjugation (a peculiar feature of dimension 3). We derive an asymptotic formula for the eigenvalue with smallest modulus for arbitrary perturbations of the metric and present two particular families of Riemannian metrics for which the eigenvalue with smallest modulus can be evaluated explicitly. We also establish a relation between our asymptotic formula and the eta invariant.
Near-edge band structures and band gaps of Cu-based semiconductors predicted by the modified Becke-Johnson potential plus an on-site Coulomb U
Authors: Zhang Yubo , Zhang Jiawei , Gao Weiwei , Abtew Tesfaye A. , Wang Youwei , Zhang Peihong , Zhang Wenqing
Published: November 2013

Diamond-like Cu-based multinary semiconductors are a rich family of materials that hold promise in a wide range of applications. Unfortunately, accurate theoretical understanding of the electronic properties of these materials is hindered by the involvement of Cu d electrons. Density functional theory (DFT) based calculations using the local density approximation or generalized gradient approximation often give qualitative wrong electronic properties of these materials, especially for narrow-gap systems. The modified Becke-Johnson (mBJ) method has been shown to be a promising alternative to more elaborate theory such as the GW approximation for fast materials screening and predictions. However, straightforward applications of the mBJ method to these materials still encounter significant difficulties because of the insufficient treatment of the localized d electrons. We show that combining the promise of mBJ potential and the spirit of the well-established DFT + U method leads to a much improved description of the electronic structures, including the most challenging narrow-gap systems. A survey of the band gaps of about 20 Cu-based semiconductors calculated using the mBJ + U method shows that the results agree with reliable values to within ±0.2 eV.
Interaction of nonthermal muon beam with electron-positron-photon plasma: A thermal field theory approach
Authors: Noorian Zainab , Eslami Parvin , Javidan Kurosh
Published: November 2013

Interaction of a muon beam with hot dense QED plasma is investigated. Plasma system contains electrons and positrons with Fermi-Dirac distribution and Bose-Einstein distributed photons while the beam particles have nonthermal distribution. The energy loss of the beam particles during the interaction with plasma is calculated to complete leading order of interaction in terms of the QED coupling constant using thermal field theory approach. The screening effects of the plasma are computed consistently using resummation of perturbation theory with hard thermal loop approximation according to the Braaten-Pisarski method. Time evolution of the plasma characteristics and also plasma identifications during the interaction are investigated. Effects of the nonthermal parameter of the beam distribution on the energy exchange and the evolution of plasma-beam system are also explained.
Electron attachment to indole and related molecules
Authors: Modelli Alberto , Jones Derek , Pshenichnyuk Stanislav A.
Published: November 2013

Gas-phase formation of temporary negative ion states via resonance attachment of low-energy (0–6 eV) electrons into vacant molecular orbitals of indoline (I), indene (II), indole (III), 2-methylen-1,3,3-trimethylindoline (IV), and 2,3,3-trimethyl-indolenine (V) was investigated for the first time by electron transmission spectroscopy (ETS). The description of their empty-level structures was supported by density functional theory and Hartree-Fock calculations, using empirically calibrated linear equations to scale the calculated virtual orbital energies. Dissociative electron attachment spectroscopy (DEAS) was used to measure the fragment anion yields generated through dissociative decay channels of the parent molecular anions of compounds I-V, detected with a mass filter as a function of the incident electron energy in the 0–14 eV energy range. The vertical and adiabatic electron affinities were evaluated at the B3LYP/6-31+G(d) level as the anion/neutral total energy difference. The same theoretical method is also used for evaluation of the thermodynamic energy thresholds for production of the negative fragments observed in the DEA spectra. The loss of a hydrogen atom from the parent molecular anion ([M-H]−) provides the most intense signal in compounds I-IV. The gas-phase DEAS data can provide support for biochemical reaction mechanisms in vivo involving initial hydrogen abstraction from the nitrogen atom of the indole moiety, present in a variety of biologically important molecules.
Non-dissociative activation of chemisorbed dinitrogen on Ni{110} by co-adsorbed lithium
Authors: Liu Tao , Temprano Israel , Jenkins Stephen J. , King David A.
Published: November 2013

Weakening the intramolecular N–N bond is essential to promote direct hydrogenation of adsorbed N2 on catalyst surfaces. The interaction of N2 with Li on Ni{110} surfaces has been investigated. We show that the N–N bond is significantly weakened with increasing Li coverage, evidenced by large redshifts in N–N stretch frequency of up to 380 cm−1 compared to the gas phase. Some increased thermal stability of the most weakened N2,ads states is also observed. We speculate that the various observed redshifts in N–N stretch frequency are associated with an enhanced backfilling of the 2π* antibonding orbital of N2 due to both the Li-induced surface electrostatic field, and the formation of Lix(N2)y surface complexes.
Optimization of the parameters of plasma liners with zero-dimensional models
Authors: Oreshkin V. I.
Published: November 2013

The efficiency of conversion of the energy stored in the capacitor bank of a high-current pulse generator into the kinetic energy of an imploding plasma liner is analyzed. The analysis is performed by using a model consisting of LC circuit equations and equations of motion of a cylindrical shell. It is shown that efficient energy conversion can be attained only with a low-inductance generator. The mode of an "ideal" load is considered where the load current at the final stage of implosion is close to zero. The advantages of this mode are, first, high efficiency of energy conversion (80%) and, second, improved stability of the shell implosion. In addition, for inertial confinement fusion realized by the scheme of a Z pinch dynamic hohlraum, not one but several fusion targets can be placed in the cavity on the pinch axis due to the large length of the liner.
Electron acceleration by Z-mode and whistler-mode waves
Authors: Lee K. H. , Omura Y. , Lee L. C.
Published: November 2013

We carried out a series of particle simulations to study electron acceleration by Z-mode and whistler-mode waves generated by an electron ring distribution. The electron ring distribution leads to excitations of X-mode waves mainly in the perpendicular direction, Z-mode waves in the perpendicular and parallel directions, and whistler-mode waves mainly in the parallel direction. The parallel Z- and whistler-mode waves can lead to an effective acceleration of ring electrons. The electron acceleration is mainly determined by the wave amplitude and phase velocity, which in turn is affected by the ratio of electron plasma to cyclotron frequencies. For the initial kinetic energy ranging from 100 to 500 keV, the peak energy of the accelerated electrons is found to reach 2–8 times the initial kinetic energy. We further study the acceleration process by test-particle calculations in which electrons interact with one, two, or four waves. The electron trajectories in the one-wave case are simple diffusion curves. In the multi-wave cases, electrons are accelerated simultaneously by counter-propagating waves and can have a higher final energy.
Bandgap engineering of Cu2CdxZn1−xSnS4 alloy for photovoltaic applications: A complementary experimental and first-principles study
Authors: Xiao Zhen-Yu , Li Yong-Feng , Yao Bin , Deng Rui , Ding Zhan-Hui , Wu Tom , Yang Gang , Li Chun-Ran , Dong Zi-Yuan , Liu Lei , Zhang Li-Gong , Zhao Hai-Feng
Published: November 2013

We report on bandgap engineering of an emerging photovoltaic material of Cu2CdxZn1−xSnS4 (CCZTS) alloy. CCZTS alloy thin films with different Cd contents and single kesterite phase were fabricated using the sol-gel method. The optical absorption measurements indicate that the bandgap of the kesterite CCZTS alloy can be continuously tuned in a range of 1.55–1.09 eV as Cd content varied from x = 0 to 1. Hall effect measurements suggest that the hole concentration of CCZTS films decreases with increasing Cd content. The CCZTS-based solar cell with x = 0.47 demonstrates a power conversion efficiency of 1.2%. Our first-principles calculations based on the hybrid functional method demonstrate that the bandgap of the kesterite CCZTS alloy decreases monotonically with increasing Cd content, supporting the experimental results. Furthermore, Cu2ZnSnS4/Cu2CdSnS4 interface has a type-I band-alignment with a small valence-band offset, explaining the narrowing of the bandgap of CCZTS as the Cd content increases. Our results suggest that CCZTS alloy is a potentially suitable material to fabricate high-efficiency multi-junction tandem solar cells with different bandgap-tailored absorption layers.
Swift heavy ion irradiation of ZnO nanoparticles embedded in silica: Radiation-induced deoxidation and shape elongation
Authors: Amekura H. , Okubo N. , Ishikawa N. , Tsuya D. , Mitsuishi K. , Nakayama Y. , Singh U. B. , Khan S. A. , Mohapatra S. , Avasthi D. K.
Published: November 2013

ZnO nanoparticles (NPs) embedded in amorphous SiO2 were irradiated with 200 MeV Xe14+ swift heavy ions (SHIs) to a fluence of 5.0 × 1013 ions/cm2. Optical linear dichroism was induced in the samples by the irradiation, indicating shape transformation of the NPs from spheres to anisotropic ones. Transmission electron microscopy observations revealed that some NPs were elongated to prolate shapes; the elongated NPs consisted not of ZnO but of Zn metal. The SHI irradiation induced deoxidation of small ZnO NPs and successive shape elongation of the deoxidized metal NPs.
Experimental investigation of the structure and the dynamics of nanosecond laser-induced plasma in 1-atm argon ambient gas
Authors: Ma Qianli , Motto-Ros Vincent , Bai Xueshi , Yu Jin
Published: November 2013

We have investigated the structure and the dynamics of the plasma induced on a metallic target in 1-atm argon ambient by a nanosecond laser pulse with irradiance in the range of 10 GW/cm2. The structure is revealed to be sensitively dependent on the laser wavelength. A layered structure of different species characterizes the plasma induced by ultraviolet 355 nm pulse, while an effective mixing between the ablation vapor and the shocked ambient gas is observed with infrared 1064 nm pulse. The absorption property of the shocked gas is found to be crucial for determining the structure of the plasma.
Electrical properties of Si/Si interfaces by using surface-activated bonding
Authors: Liang J. , Miyazaki T. , Morimoto M. , Nishida S. , Shigekawa N.
Published: November 2013

Electrical properties of n-Si/n-Si, p-Si/n-Si, and p−-Si/n+-Si junctions fabricated by using surface-activated-bonding are investigated. The transmission electron microscopy/energy dispersive X-ray spectroscopy of the n-Si/n-Si interfaces reveals no evidence of oxide layers at the interfaces. From the current-voltage (I-V) and the capacitance-voltage (C-V) characteristics of the p-Si/n-Si and p−-Si/n+-Si junctions, it is found that the interface states, likely to have formed due to the surface activation process using Ar plasma, have a more marked impact on the electrical properties of the p-Si/n-Si junctions. An analysis of the temperature dependence of the I-V characteristics indicates that the properties of carrier transport across the bonding interfaces for reverse-bias voltages in the p-Si/n-Si and p−-Si/n+-Si junctions can be explained using the trap-assisted-tunneling and Frenkel-Poole models, respectively.
Note: Near infrared spectral and transient measurements of PbS quantum dots luminescence
Authors: Parfenov P. S. , Litvin A. P. , Ushakova E. V. , Fedorov A. V. , Baranov A. V. , Berwick K.
Published: November 2013

We describe an experimental setup for the characterization of luminescence from nanostructures. The setup is intended for steady-state and time-resolved luminescence measurements in the near-infrared region. The setup allows us to study spectral luminescence properties in the spectral range of 0.8–2.0 μm with high spectral resolution and kinetic luminescence properties between 0.8 and 1.7 μm with a time resolution of 3 ns. The capabilities of the system are illustrated by taking luminescence measurements from PbS quantum dots. We established the size dependencies of the optical properties of the PbS quantum dots over a wide spectral range. Finally, the energy transfer process was studied with a high temporal and spectral resolution.
Combined short scale roughness and surface dielectric function gradient effects on the determination of tip-sample force in atomic force microscopy
Authors: Gusso André
Published: November 2013

The contribution of tip roughness to the van der Waals force between an atomic force microscopy probe tip and the sample is calculated using the multilayer effective medium model, which allows us to consider the relevant case of roughness characterized by correlation length and amplitude in the nanometer scale. The effect of the surface dielectric function gradient is incorporated in the tip-sample force model. It is concluded that for rms roughness in the few nanometers range the effect of short scale tip roughness is quite significant.
Networks of silicon nanowires: A large-scale atomistic electronic structure analysis
Authors: Keleş Ümit , Liedke Bartosz , Heinig Karl-Heinz , Bulutay Ceyhun
Published: November 2013

Networks of silicon nanowires possess intriguing electronic properties surpassing the predictions based on quantum confinement of individual nanowires. Employing large-scale atomistic pseudopotential computations, as yet unexplored branched nanostructures are investigated in the subsystem level as well as in full assembly. The end product is a simple but versatile expression for the bandgap and band edge alignments of multiply-crossing Si nanowires for various diameters, number of crossings, and wire orientations. Further progress along this line can potentially topple the bottom-up approach for Si nanowire networks to a top-down design by starting with functionality and leading to an enabling structure.
Real-time atomic-resolution imaging of crystal growth process in water by phase modulation atomic force microscopy at one frame per second
Authors: Miyata Kazuki , Asakawa Hitoshi , Fukuma Takeshi
Published: November 2013

Recent advancement in dynamic-mode atomic force microscopy (AFM) has enabled its operation in liquid with atomic-scale resolution. However, its imaging speed has often been too slow to visualize atomic-scale dynamic processes. Here, we propose a method for making a significant improvement in the operation speed of dynamic-mode AFM. In this method, we use a wideband and low-latency phase detector with an improved algorithm for the signal complexification. We demonstrate atomic-scale imaging of a calcite crystal growth process in water at one frame per second. The significant improvement in the imaging speed should enable various studies on unexplored atomic-scale interfacial processes.
Communication: Nuclear quadrupole moment-induced Cotton-Mouton effect in noble gas atoms
Authors: Fu Li-juan , Rizzo Antonio , Vaara Juha
Published: November 2013

New, high-sensitivity and high-resolution spectroscopic and imaging methods may be developed by exploiting nuclear magneto-optic effects. A first-principles electronic structure formulation of nuclear electric quadrupole moment-induced Cotton-Mouton effect (NQCME) is presented for closed-shell atoms. In NQCME, aligned quadrupole moments alter the index of refraction of the medium along with and perpendicular to the direction of nuclear alignment. The roles of basis-set convergence, electron correlation, and relativistic effects are investigated for three quadrupolar noble gas isotopes: 21Ne, 83Kr, and 131Xe. The magnitude of the resulting ellipticities is predicted to be 10−4–10−6 rad/(M cm) for fully spin-polarized nuclei. These should be detectable in the Voigt setup. Particularly interesting is the case of 131Xe, in which a high degree of spin polarization can be achieved via spin-exchange optical hyperpolarization.
Schottky barrier height measurements of Cu/Si(001), Ag/Si(001), and Au/Si(001) interfaces utilizing ballistic electron emission microscopy and ballistic hole emission microscopy
Authors: Balsano Robert , Matsubayashi Akitomo , LaBella Vincent P.
Published: November 2013

The Schottky barrier heights of both n and p doped Cu/Si(001), Ag/Si(001), and Au/Si(001) diodes were measured using ballistic electron emission microscopy and ballistic hole emission microscopy (BHEM), respectively. Measurements using both forward and reverse ballistic electron emission microscopy (BEEM) and (BHEM) injection conditions were performed. The Schottky barrier heights were found by fitting to a linearization of the power law form of the Bell-Kaiser BEEM model. The sum of the n-type and p-type barrier heights are in good agreement with the band gap of silicon and independent of the metal utilized. The Schottky barrier heights are found to be below the region of best fit for the power law form of the BK model, demonstrating its region of validity.
Laser Flash Photolysis on Electron Transfer Reactions between 1,8-Dihydroxyanthraquinone with Adenine and Cytosine
Authors: Liu Xiang , Chen Lin , Zhou Qiao-hui , Zhou Xiao-guo , Liu Shi-lin
Published: November 2013

Electron transfer (ET) reactions between 1,8-dihydroxyanthraquinone (DHAQ) and two DNA bases, adenine (A) and cytosine (C), have been investigated in CH3CN/H2O solution with nanosecond time-resolved laser flash photolysis. After irradiation at 355 nm, the triplet DHAQ is produced via intersystem crossing and reacts with two nucleobases. ET processes for both reactions have been definitely identified, in which two bases play a significant role of electron donor. Based on the measured decay dynamics of various intermediates and the corresponding quenching rates, an initial ET process followed by a secondary proton-transfer reaction is suggested for both the overall reactions. By plotting the observed quenching rate against the concentration of two DNA bases, the bimolecular quenching rate constants are determined as 9.0×108 L/(mol?s) for the 3DHAQ*+C reaction and 3.3×108 L/(mol?s) for the 3DHAQ*+A reaction, respectively.
Analysis of Potential Energy Surface for Butanone Isomerization
Authors: Yang Xue , Yan Bing , Xu Hai-feng , Zhu Rui-han , Zhang Mei-xia , Ding Da-jun
Published: November 2013

The potential energy surfaces for butanone isomerization have been investigated by density function theory calculation. Six main reaction pathways are confirmed using the intrinsic reaction coordinate method, and the corresponding isomerization products are 1-buten-2-ol, 2-buten-2-ol, butanal or 1-buten-1-ol, methyl 1-propenyl ether, methyl allyl ether, and ethyl vinyl ether, respectively. Among them, there are three pathways through butylene oxide, indicating butylene oxide is an important intermediate product during butanone isomerization. The calculated vertical ionization energies of the reactant and its products are in a good agreement with the experimental values available. From the consideration for the relative energies of transition states and the number of high-energy barriers we infer that the reaction pathway butanone→1-buten-2-ol →2-buten-2-ol is the most competitive. The obtained results are informative for future studies on isomerization of ketone molecules.
Theoretical Investigation on Interaction between Guanine and Luteolin
Authors: Li Lai-cai , Bai Kun-kun , Cai Wan-fei
Published: November 2013

The interacting patterns of the luteolin and guanine have been investigated by using the density functional theory B3LYP method with 6−31+G* basis set. Eighteen stable structures for the luteolin-guanine complexes have been found respectively. The results indicate that the complexes are mainly stabilized by the hydrogen bonding interactions. Meanwhile, both the number and strength of hydrogen bond play important roles in determining the stability of the complexes which can form two or more hydrogen bonds. Theories of atoms in molecules and natural bond orbital have also been utilized to investigate the hydrogen bonds involved in all the systems. The interaction energies of all the complexes which were corrected by basis set superposition error are 6.04–56.94 kJ/mol. The calculation results indicate that there are strong hydrogen bonding interactions in the luteolin-guanine complexes. We compared the interaction between luteolin and four bases of DNA, and found luteolin-thymine was the strongest and luteolin-adenine was the weakest. The interaction between luteolin and DNA bases are all stronger than luteolin-water.
DFT Study on Homolytic Dissociation Enthalpies of C—I Bonds
Authors: Zheng Wen-rui , Chen Zhi-chong , Xu Wu-xia
Published: November 2013

The C—I bond dissociation enthalpies (BDE) of various organic iodides were calculated using high-level theoretical methods including MP2 and CCSD(T) with extrapolated basis set as well as a number of density functional theory methods. After systematic evaluation of the theoretical results against available experimental C—I BDEs, it was found that the MPW-LYP1M method gave the lowest root mean square error. We, therefore, used this method to examine the substituent effects on different categories of C(sp3)—I and C(sp2)—I bonds. Furthermore, the remote substituent effects on the C—I BDEs of substituted iodobenzenes and substituted (iodomethyl)benzenes were also investigated at the same level. The C—I BDEs of typical heteroaromatic iodides including five-membered and six-membered heterocyclic iodides were also examined.
Mean Residence Time of CO2 Molecules in Flexible ZIF-8 Cages Explored by Molecular Dynamics Simulations
Authors: Yang Zhen , Liu Lian , Gui Tian , Zhou Rong-fei , Chen Xiang-shu
Published: November 2013

The adsorption sites and diffusion mechanism of CO2 molecules in the flexible Zn(MeIM)2 (MeIM=2-methylimidazole) (ZIF-8) have been investigated by grand canonical Monte Carlo and molecular dynamics simulations. A reasonable time correlation function is for the first time constructed to explore the mean residence time of CO2 molecules in the ZIF-8 cages, suggesting that CO2 molecules can remain in the same cage for up to several tens of picoseconds. Furthermore, we find that the mean residence time almost linearly increases with the increasing pressure (or loading) at 273 and 298 K.
Orthorhombic γ-LiV2O5 as Cathode Materials in Lithium Ion Batteries: Synthesis and Property
Authors: Li Na , Gong Hua-xu , Qian Yi-tai
Published: November 2013

The rod-like and bundle-like γ-LiV2O5 were synthesized via a simple solvothermal processing. The rod-like γ-LiV2O5 with diameter of 500–800 nm and the bundle-like architectures are composed of several of order-attached rods with diameter of 100–600 nm. γ-LiV2O5 were synthesized using LiOH·H2O, NH4VO3, HNO3, C2H5OH without and with PVP as raw materials. At the same time, the actual formation mechanism of γ-LiV2O5 was also investigated. As the cathode materials for lithium ion batteries, the bundle-like γ-LiV2O5 prepared with PVP delivers a better electrochemical performance, which has an initial discharge capacity of 269.3 mAh/g at a current density of 30 mA/g and is still able to achieve 228 mAh/g after the 20th cycle. The good electrochemical properties of the as-synthesized γ-LiV2O5 coupled with the simple, relatively low temperature, and low cost of the preparation method may make this material a promising candidate as a cathode material for lithium ion batteries.
Fabrication of Highly Conductive Pd Nanowires using PDMS Transfer Method on DNA Scaffolds through Ethanol-Reduction
Authors: Cai Hong-bing , Wang Zhen-xing , Liu Jin-yang , Zhang Kun , Wang Xiao-ping
Published: November 2013

We have developed a simple, productive, and effective poly(dimethysiloxane) (PDMS) transfer method to fabricate highly conductive Pd nanowires following DNA scaffolds on various substrates, based on ethanol-reduction at low temperature. Pd nanoparticles were selectively deposited and confined onto the DNA templates on a PDMS sheet to form Pd nanowires and then the nanowires were transferred to other various substrates with a low occurrence of parasitic nanoparticles. The structure, morphology and the conductance of Pd nanowires were characterized with transmission electron microscopy, field emission scanning electron microscopy, and electrical transport measurement, respectively. Moreover, the growth process of the Pd nanowires was investigated by varying the incubation time and reaction temperature. The present strategy provides a new method to fabricate extremely dense, highly conductive, and well aligned Pd nanowires on various substrates, which make it promising for building nanosensors and nanoelectronic devices.
An Efficient One-pot Two-component Protocol for Regio- and Chemoselective Synthesis of 5-Aryloyl-1,3,7,9-tetraalkyl-2,8-dithioxo-2,3,8,9-tetrahydro-1H-pyrano[2,3-d:6,5-d′]dipyrimidine-4,6(5H,7H)-diones
Authors: Rimaz Mehdi , Rabiei Hossein , Khalili Behzad , Prager Rolf H.
Published: November 2013

Novel symmetric fused pyrano[2,3-d]pyrimidine derivatives were synthesized in 75–92 % yield by a one-pot two-component reaction of arylglyoxals and 1,3-dialkyl-2-thiobarbituric acids in ethanol at room temperature. This is the first protocol to be reported for the synthesis of 5-aryloyl-1,3,7,9-tetraalkyl-2,8-dithioxo-2,3,8,9-tetrahydro-1H-pyrano[2,3-d:6,5-d′]dipyrimidine-4,6(5H,7H)-diones and the significant features of the present protocol are simplicity, high yields, a simple isolation procedure, and high chemoselectivity.
Summer fallow weed control and residue management impacts on winter crop yield though soil water and N accumulation in a winter-dominant, low rainfall region of southern Australia
Authors: Hunt J. R. , Browne C. , McBeath T. M. , Verburg K. , Craig S. , Whitbread A. M.
Published: November 2013

The majority of rain used by winter grain crops in the Mallee region of Victoria, Australia, falls during the cooler months of the year (April–October). However, rain falling during the summer fallow period (November–March) and stored as soil moisture contributes to grain yield. Strategies to better capture and store summer fallow rain include (i) retention of crop residues on the soil surface to improve water infiltration and evaporation; and (ii) chemical or mechanical control of summer fallow weeds to reduce transpiration. Despite the widespread adoption of no-till farming systems in the region, few published studies have considered the benefits of residue management during the summer fallow relative to weed control, and none quantify the impacts or identify the mechanisms by which summer fallow weeds influence subsequent crop yield.
Over 3 years (2009–11), identical experiments on adjacent sand and clay soil types at Hopetoun in the southern Mallee were conducted to quantify the effect of residue management (standing, removed, or slashed) and summer fallow weed control (± chemical control) compared with cultivation on soil water and nitrogen (N) accumulation and subsequent crop yield. The presence of residue (2.4–5.8 t/ha) had no effect on soil water accumulation and a small negative effect on grain yield on the clay soil in 2011. Controlling summer weeds (Heliotropium europaeum and volunteer crop species) increased soil water accumulation (mean 45 mm) and mineral N (mean 45 kg/ha) before sowing on both soil types in 2 years of the experiment with significant amounts of summer fallow rain (2010 and 2011). Control of summer weeds increased grain yield of canola by 0.6 t/ha in 2010 and wheat by 1.4 t/ha in 2011. Using the data from these experiments to parameterise the APSIM model, simulation of selected treatments using historical climate data (1958–2011) showed that an extra 40 mm of stored soil water resulted in an average additional 0.4 t/ha yield, most of which was achieved in dry growing seasons. An additional 40 kg/ha N increased yield only in wetter growing seasons (mean 0.4 t/ha on both soil types). The combination of extra water and N that was found experimentally to result from control of summer fallow weeds increased subsequent crop yield in all season types (mean 0.7 t/ha on sand, 0.9 t/ha on clay). The co-limitation of yield by water and N in the Mallee environment means that yield increases due to summer weed control (and thus returns on investment) are very reliable.
The Nature Study Idea in New South Wales: The Role of Charles Tucker Musson (1856–1928)
Authors: Kass Dorothy
Published: November 2013

Charles Tucker Musson was a highly respected teacher at Hawkesbury Agricultural College from 1891 to 1919 and a prolific contributor of articles to scientific and other journals in New South Wales. In addition, he became a strong advocate of Nature Study, a subject widely discussed as it was introduced to schools throughout the English-speaking world in the early twentieth century but since fallen into obscurity within historical research. Musson's understandings of ecology and adaptation promoted a holistic study of nature. For him any action that affected the natural environment had wider implications that needed to be understood. He came to believe that environmental understanding required more than factual scientific investigation and thus embraced the additional appeal to emotional attachment and aesthetic appreciation that Nature Study endorsed. A study of his life and writing thus provides insight into the particular ideology of Nature Study as it was introduced into New South Wales schools and its wider connection with conservationist and preservationist thought.
How do primary health-care practitioners identify and manage communication impairments in preschool children?
Authors: Woolfenden Sue , Short Kate , Blackmore Roger , Pennock Rene , Moore Michael
Published: November 2013

Communication impairments (CIs) in preschool children are common and can have long-term adverse consequences if not detected and treated early. This study investigated the knowledge, training and practice of primary health-care practitioners in the identification and management of CIs in preschool-aged children. A cross-sectional survey of 277 primary health-care practitioners in the Inner West and South West Sydney was undertaken. The majority of practitioners surveyed understood the importance of early identification of CIs. Eight per cent of practitioners correctly identified all of the ‘red flags’ for verbal and non-verbal communication. The majority (80%) correctly described the management of a typical case presentation. Two-thirds of practitioners reported using a tool in their practice for developmental surveillance, but the quality of surveillance tools was variable. One-third felt their training in this area was poor and 90% indicated they would like further training. Barriers to referral included waiting times, availability and cost of services. We concluded that primary health-care practitioners are aware that CIs are significant and they need to be identified early. There are opportunities for further training and promoting high-quality developmental surveillance in primary care. In addition, there are broader health system issues that include promotion of an integrated response to the detection and management of CIs.
Responding to Australia's National Hepatitis B Strategy 2010–13: gaps in knowledge and practice in relation to Indigenous Australians
Authors: Olsen Anna , Wallace Jack , Maher Lisa
Published: November 2013

The Australian National Hepatitis B Strategy 2010–13 outlines five priority areas for developing a comprehensive response to the hepatitis B virus (HBV): building partnerships and strengthening community action; preventing HBV transmission; optimising diagnosis and screening; clinical management of people with chronic hepatitis B (CHB); and developing health maintenance, care and support for people with HBV. A scoping study was used to map the main sources and types of evidence available on the epidemiology and natural history of HBV among Indigenous Australians as well as public health responses published since 2001 (January 2001–May 2013). Gaps in current knowledge were identified. While the literature documents the success of universal infant immunisation and indicates the potential for screening initiatives to identify infected and susceptible individuals, prevalence of CHB and hepatocellular cancer remain high in Indigenous Australians. Significant gaps in knowledge and practice were identified in relation to each of the five National Hepatitis B Strategy priority action areas. Successful implementation of the strategy in Indigenous communities and reducing the burden of HBV and hepatocellular cancer in Indigenous Australians will require increased investment in research and knowledge transfer across all priority areas.
Tolerance of spermatozoa to hypotonic stress: role of membrane fluidity and correlation with cryosurvival
Authors: Oldenhof Harriëtte , Heutelbeck Anna , Blässe Anne-Kathrin , Bollwein Heinrich , Martinsson Gunilla , Wolkers Willem F. , Sieme Harald
Published: November 2013

The aim of this study was to evaluate inter-individual variability in osmotic properties of stallion spermatozoa and its correlation with cryosurvival. In addition, temperature dependency of hypo-osmotic tolerance and membrane fluidity were studied. Stallion sperm membranes exhibited good resistance towards hypotonic stress in the 15–30°C temperature range, whereas membrane stability was found to be decreased at 4 and 37°C. Bull spermatozoa showed greater hypo-osmotic tolerance compared with stallion spermatozoa, especially at temperatures above 30°C, which coincided with decreased membrane fluidity of bovine spermatozoa in this temperature range. The critical osmolality at 22°C, at which half of the sperm population survived exposure to hypotonic saline solution, was found to vary between 55 and 170 mOsm kg–1 among different stallions. Clear correlations were found for pre- versus post-freeze sperm motility and membrane integrity. Pre-freeze percentages of membrane-intact spermatozoa after exposure to hypotonic stress showed a weak correlation with sperm motility after cryopreservation. This correlation, however, was not found when data were corrected for initial numbers of membrane-intact spermatozoa in the sample. We thus conclude that studies on pre-freeze tolerance towards hypotonic stress cannot be used to predict sperm cryosurvival rates for individual stallions.
The Safety of Aquaflor (50% Florfenicol) Administered in Feed to Fingerling Yellow Perch
Authors: Bowker James D , Carty Dan , Bowman Molly P
Published: November 2013

Aquaflor is an aquaculture feed premix containing 50% florfenicol and is approved for use in more than 50 countries to control mortality in a variety of cultured fishes caused by diseases associated with infectious bacterial pathogens. As part of an effort to expand the current approval in the United States, we conducted a study to evaluate the safety of Aquaflor to Yellow Perch Perca flavescens when administered in feed at 0× (0 mg/kg), 1× (15 mg/kg), 3× (45 mg/kg), or 5× (75 mg/kg) the proposed maximum therapeutic treatment dose of 15 mg florfenicol·kg fish−1·d−1 for 20 consecutive days, 2× the proposed therapeutic treatment duration of 10 consecutive days. Fingerling Yellow Perch (7.8 ± 1.6 cm and 5.0 ± 3.4 g; mean ± SD) were stocked into flow-through test tanks at 15 fish per tank, and treatments were randomly assigned to tanks in triplicate. At the end of the 20-d exposure period, mean cumulative mortality in the 0× and 3× groups (6.7% for both) was greater than that in the 1× and 5× groups (2.2% and 0.0%, respectively); however, differences among the groups were not significant (P = 0.3741). Throughout the study, general fish behavior was characterized as normal, and fish consumed virtually all feed offered. Fish health and histology assessments revealed no signs or lesions associated with toxicity of florfenicol. In conclusion, there is an adequate margin of safety associated with administering Aquaflor-medicated feed to fingerling Yellow Perch at the proposed therapeutic treatment regimen of 15 mg florfenicol·kg fish−1·d−1 for 10 d.
The Effect of Stocking Different Ratios of Nile Tilapia Oreochromis niloticus, Striped Mullet Mugil cephalus, and Thinlip Grey Mullet Liza ramada in Polyculture Ponds on Biomass Yield, Feed Efficiency, and Production Economics
Authors: Tahoun Al-Azab , Suloma Ashraf , Hammouda Yasser , Abo-State Hanan , El-Haroun Ehab
Published: November 2013

A 180-d trial was done to evaluate the effect of stocking different ratios of Nile Tilapia Oreochromis niloticus, Striped Mullet Mugil cephalus, and Thinlip Grey Mullet Liza ramada on production and economic return in brackish-water ponds. The trial was conducted in twelve 3,000-m2 earthen ponds with four treatments (3 ponds/treatment): Nile Tilapia alone (100% Nile Tilapia, monoculture group [MG]); 75% Nile Tilapia and 25% Thinlip Grey Mullet (polyculture group 1 [PG1]); 75% Nile Tilapia, 12.5% Thinlip Grey Mullet, and 12.5% Striped Mullet (PG2); and 75% Nile Tilapia and 25% Striped Mullet (PG3). Fish were fed a commercial diet containing 25% crude protein twice per day. The efficiency of feed utilization was determined in terms of feed conversion ratio (FCR; feed intake/weight gain). Polyculture group 3 had the best FCR, whereas the FCR results did not differ significantly among the MG, PG1, and PG2 treatments. In addition, PG3 had the highest total yield (3,350.3 kg/pond), followed in descending order by PG2 (3,234.4 kg/pond), PG1 (3,078.4 kg/pond), and MG (2,856.3 kg/pond). The PG3 treatment achieved the highest net financial return, followed by PG2, PG1, and MG. This study indicates that tilapia–mullet polyculture may improve the efficiency with which natural food resources are used within the system, resulting in better environmental quality, system sustainability, feed utilization, and net financial return.
Opposing actions of septins and Sticky on Anillin promote the transition from contractile to midbody ring
Authors: El Amine Nour , Kechad Amel , Jananji Silvana , Hickson Gilles R.X.
Published: November 2013

During cytokinesis, closure of the actomyosin contractile ring (CR) is coupled to the formation of a midbody ring (MR), through poorly understood mechanisms. Using time-lapse microscopy of Drosophila melanogaster S2 cells, we show that the transition from the CR to the MR proceeds via a previously uncharacterized maturation process that requires opposing mechanisms of removal and retention of the scaffold protein Anillin. The septin cytoskeleton acts on the C terminus of Anillin to locally trim away excess membrane from the late CR/nascent MR via internalization, extrusion, and shedding, whereas the citron kinase Sticky acts on the N terminus of Anillin to retain it at the mature MR. Simultaneous depletion of septins and Sticky not only disrupted MR formation but also caused earlier CR oscillations, uncovering redundant mechanisms of CR stability that can partly explain the essential role of Anillin in this process. Our findings highlight the relatedness of the CR and MR and suggest that membrane removal is coordinated with CR disassembly.
Death of developing neurons: New insights and implications for connectivity
Authors: Dekkers Martijn P.J. , Nikoletopoulou Vassiliki , Barde Yves-Alain
Published: November 2013

The concept that target tissues determine the survival of neurons has inspired much of the thinking on neuronal development in vertebrates, not least because it is supported by decades of research on nerve growth factor (NGF) in the peripheral nervous system (PNS). Recent discoveries now help to understand why only some developing neurons selectively depend on NGF. They also indicate that the survival of most neurons in the central nervous system (CNS) is not simply regulated by single growth factors like in the PNS. Additionally, components of the cell death machinery have begun to be recognized as regulators of selective axonal degeneration and synaptic function, thus playing a critical role in wiring up the nervous system.
Chris Bakal: Look and learn
Authors: Sedwick Caitlin
Published: November 2013

Bakal studies the signaling networks that control cell shape.
Measuring credit capacity on Danish farms using DEA
Authors: Friis Pedersen Michael , Vesterlund Olsen Jakob
Published: November 2013

Purpose

– The purpose of this paper is to introduce a novel measure of access to credit suited to estimate the relative change in credit reserves.

Design/methodology/approach

– A debt possibility frontier is estimated using data envelopment analysis and the Malmquist index is calculated. The Malmquist index is redubbed the Debt Development index and decomposed into “change in debt capacity” and “change in debt capacity utilization”. Bootstrapping is applied for statistical inference. The method is applied to an unbalanced panel of 92,000 Danish farm accounts from 1996 to 2009.

Findings

– The paper finds that credit capacity roughly doubled for Danish farmers over the period, and that utilization of credit capacity generally was proportional to capacity change, utilization being higher for dairy and pig farms, than for crop farms.

Research limitations/implications

– Changes in credit reserves may have important implications for risk management practice, investment and technology adoption and related policy issues. The method is limited by the possibility of strategic behavior of lenders during credit cycle busts. In credit cycle booms, the method gives a good basis for the estimates of change in credit reserves.

Practical implications

– In a period of increasing credit reserves, risk management institutions are unlikely to develop. Like agricultural policy, access to credit may crowd out market-based risk management.

Originality/value

– The study represents a novel application and interpretation of a well-known method.
Quantifying the sources of revenue variation in the Northern Great Plains
Authors: C. Hadrich Joleen
Published: November 2013

Purpose

– The purpose of this paper is to determine the sources and factors affecting farm revenue variation on crop and livestock farms in the Northern Great Plains.

Design/methodology/approach

– A two method approach is used. Variance decomposition analysis is completed on an 18-year balanced panel data set of North Dakota producers to determine the sources of farm revenue variation. The second component of this research uses a random effects estimator to determine the effect of farm characteristics on farm revenue variation measured by coefficient of variation.

Findings

– Crop revenue is the largest source of farm revenue variation, with crop insurance being the largest source of revenue variation diversification. Small market crops and corn were found to increase revenue variation compared to those operations that received the largest sum of their revenue from wheat. Government payments and insurance payments were also found to increase farm revenue variation indicating they may provide an incentive to plant more risky crops.

Originality/value

– This analysis examined specific enterprises that affect farm revenue variation, which has not been examined in earlier work. This distinction allows for focus on potential policy implications of small market crops and new crops in “transitional planting zones”.
Resettled refugee community perspectives to the Canterbury earthquakes
Authors: Marlowe Jay
Published: November 2013

Purpose

– This research project examined resettled refugees’ perspectives on the Canterbury Earthquakes to better understand the organisational implications for disaster preparedness and response with culturally and linguistically diverse groups.

Design/methodology/approach

– The method of data collection for this exploratory pilot study involved conducting semi-structured focus group discussions during January 2012 with the Bhutanese, Afghani and Ethiopian communities. The project was conducted in partnership with Refugee Services Aotearoa which is New Zealand's primary refugee resettlement organisation.

Findings

– The participant comments identify the importance of local ethnic community responses to a natural disaster. The need for a pre-established meeting centre(s) and community liaisons with key support organisations was highlighted as vital. Central to recovery is how organisations can work alongside refugee communities in disaster preparedness and response opportunities.

Originality/value

– The paper offers insight into the additional considerations of disaster risk reduction strategies with refugee background communities – a group that is relatively under-researched in disaster contexts.