bluuebunny/crossref_metadata_2025 huggingface dataset:
Ab initiodynamics trajectory study of the heterolytic cleavage of H2 by a Lewis acid [B(C6F5)3] and a Lewis base [P(tBu)3]
Authors: Pu Maoping , Privalov Timofei
Published: April 2013

Activation of H2 by a “frustrated Lewis pair” (FLP) composed of B(C6F5)3 and P(tBu)3 species has been explored with high level direct ab initio molecular dynamics (AIMD) simulations at finite temperature (T = 300 K) in gas phase. The initial geometrical conditions for the AIMD trajectory calculations, i.e., the near attack conformations of FLP + H2, were devised using the host-guest model in which suitable FLP conformations were obtained from the dynamics of the B(C6F5)3/P(tBu)3 pair in gas phase. AIMD trajectory calculations yielded microscopic insight into effects which originate from nuclear motion in the reacting complex, e.g., the alternating compression/elongation of the boron-phosphorous distance and the change of the pyramidality of boron in B(C6F5)3. The ensemble averaged trajectory analysis has been compared with the minimum energy path (MEP) description of the reaction. Similar to MEP, AIMD shows that an attack of the acid/base pair on the H–H bond gives rise to the polarization of the H2 molecule and as a consequence generates a large dipole moment of the reacting complex. The MEP and AIMD portrayals of the reaction are fundamentally different in terms of the magnitude of the motion of nuclei in B(C6F5)3 and P(tBu)3 during the H2 cleavage. In the AIMD trajectory simulations, geometries of B(C6F5)3 and P(tBu)3 appear as nearly “frozen” on the short time scale of the H2 cleavage. This is contrary to the MEP picture. Several of the concepts which arise from this work, e.g., separation of time scales of nuclear motion and the time-dependence of the donor-acceptor interactions in the reacting complex, are important for the understanding of chemical reactivity and catalysis.
Electronic spectroscopy and electronic structure of diatomic IrSi
Authors: Garcia Maria A. , Vietz Carolin , Ruipérez Fernando , Morse Michael D. , Infante Ivan
Published: April 2013

The optical spectrum of diatomic IrSi has been investigated for the first time, with transitions observed in the range from 17 178 to 23 858 cm−1 (582–419 nm). A rich spectrum has been recorded, consisting of 14 electronic band systems and a number of unclassified bands. Thirty-one bands have been investigated with rotational resolution, allowing the ground state to be identified as X2Δ5/2 arising from the 1σ21π42σ21δ33σ2 configuration. The ground X2Δ5/2 state is characterized by ΔG1/2 = 533 cm−1 and r0 = 2.0899(1) Å for the more abundant isotopic form, 193Ir28Si (57.8%). The measured excited electronic states have equilibrium bond lengths ranging from 2.17 to 2.25 Å and vibrational frequencies ranging from 365 to 452 cm−1. Ab initio calculations were also carried out on the molecule using the complete active space self-consistent field and multistate complete active space second-order perturbation theory methods, with relativistic and spin-orbit effects included through the restricted active space state-interaction with spin-orbit coupling method. The calculated ground state agrees with experiment, and a large number of excited states lying within 20 000 cm−1 of the ground state are reported.
Noncommutative Common Cause Principles in algebraic quantum field theory
Authors: Hofer-Szabó Gábor , Vecsernyés Péter
Published: April 2013

States in algebraic quantum field theory “typically” establish correlation between spacelike separated events. Reichenbach's Common Cause Principle, generalized to the quantum field theoretical setting, offers an apt tool to causally account for these superluminal correlations. In the paper we motivate first why commutativity between the common cause and the correlating events should be abandoned in the definition of the common cause. Then we show that the Noncommutative Weak Common Cause Principle holds in algebraic quantum field theory with locally finite degrees of freedom. Namely, for any pair of projections A, B supported in spacelike separated regions VA and VB, respectively, there is a local projection C not necessarily commuting with A and B such that C is supported within the union of the backward light cones of VA and VB and the set {C, C⊥} screens off the correlation between A and B.
Tri-Hamiltonian duality between the Wadati-Konno-Ichikawa hierarchy and the Song-Qu-Qiao hierarchy
Authors: Tian Kai , Liu Q. P.
Published: April 2013

A linear eigenvalue problem is constructed for the gradients of the eigenvalue of the Wadati-Konno-Ichikawa (WKI) spectral problem. This in turn leads to a compatible pair of Hamiltonian operators, which endows the WKI hierarchy with a bi-Hamiltonian structure. Furthermore, a proper recombination of these two Hamiltonian operators, or the duality of this bi-Hamiltonian structure, generates a coupled system of Camassa-Holm type, which is nothing but a system proposed by Song, Qu, and Qiao [J. Math. Phys. 52, 013503 (2011)]10.1063/1.3530865 recently.
Temperature–electric field hysteresis loop of electrocaloric effect in ferroelectricity—Direct measurement and analysis of electrocaloric effect. I
Authors: Wang Jinfei , Yang Tongqing , Wei Kun , Yao Xi
Published: April 2013

The polarization of polar domain in ferroelectric materials is orientated and reversed with the alternating electric field, and the hysteresis loops of polarization-electric field (P-E) and strain-electric field (S-E) are observed. For electrocaloric (EC) effect, the temperature change with the application and removal of electric field is also attributed to the change of polarization with the applied field. In most reports about EC, the temperature change is shown as an abrupt jump or slump due to the applied electric field that is a pulsed wave. Obviously, it is impossible to observe the hysteresis loop of EC. In our research, both sine wave and pulsed wave electric field are applied to samples in direct measurement, and temperature-electric field hysteresis loop (T-E) is observed only in measurement of sine wave. The T-E hysteresis loop displays a shape of butterfly, just like the shape of S-E. The electric field dependence of EC is also given. The obtained results will be helpful for us to know the electrocaloric effect further.
Manipulation of metal-insulator transition characteristics in aspect ratio-controlled VO2 micro-scale thin films on TiO2 (001) substrates
Authors: Ueda Hiroki , Kanki Teruo , Tanaka Hidekazu
Published: April 2013

We manipulated the metal-insulator transition characteristics of VO2 thin films on TiO2 (001) substrates by changing their micro-scaled metallic domain configurations through size- and aspect ratio-control. A very steep resistance drop at 294 K was demonstrated for a 1D parallel domain configuration in a low aspect ratio sample, whereas a multi-level resistance change was exhibited for a 1D series domain configuration in a high aspect ratio sample. This difference was explained using simple resistor models. The results illustrate the importance of spatially distributed metallic domain positions in tuning electrical transport properties.
Self-referenced sensing based on terahertz metamaterial for aqueous solutions
Authors: Wu Xiaojun , Pan Xuecong , Quan Baogang , Xu Xinlong , Gu Changzhi , Wang Li
Published: April 2013

We demonstrated a self-referenced sensing method in reflection geometry for characterizing aqueous solutions based on terahertz metamaterials. The sensing signal and the reference signal are taken in one measurement from different interfaces of the substrate. For ethanol-water mixture and aqueous solution of NaCl, the line-shape of the modulated response shows distinct polarity, while the peak-valley value near resonant region depends linearly on the solution concentration. These observations result from the variation of dielectric environment near the interface between the metamaterials and the aqueous solutions. This method holds promise for future application in monitoring real aqueous biosystems and ecological water systems.
A capillary dielectrophoretic chip for real-time blood cell separation from a drop of whole blood
Authors: Liao Shu-Hsien , Chang Ching-Yu , Chang Hsien-Chang
Published: April 2013

This study proposes a capillary dielectrophoretic chip to separate blood cells from a drop of whole blood (approximately 1 μl) sample using negative dielectrophoretic force. The separating efficiency was evaluated by analyzing the image before and after dielectrophoretic force manipulation. Blood samples with various hematocrits (10%–60%) were tested with varied separating voltages and chip designs. In this study, a chip with 50 μm gap design achieved a separation efficiency of approximately 90% within 30 s when the hematocrit was in the range of 10%–50%. Furthermore, glucose concentration was electrochemically measured by separating electrodes following manipulation. The current response increased significantly (8.8-fold) after blood cell separation, which was attributed not only to the blood cell separation but also to sample disturbance by the dielectrophoretic force.
Dual-band MgZnO ultraviolet photodetector integrated with Si
Authors: Hou Y. N. , Mei Z. X. , Liang H. L. , Ye D. Q. , Gu C. Z. , Du X. L.
Published: April 2013

We have constructed a dual-band ultraviolet photodetector by growing high quality MgxZn1−xO layers on Si substrate with molecular beam epitaxy. The device performance was studied by current-voltage, capacitance-voltage, spectra photoresponse, and time-resolved photoresponse characterizations. It demonstrates a high UV/visible light rejection ratio of more than 2 orders of magnitude and a fast response speed of less than 100 ms. The cutoff wavelength can be at solar-blind (280 nm)/visible-blind (301 nm) region by applying 1 V forward/2 V reverse bias. The working principle of the dual-band photodetector was finally investigated by interpretation of the specific carrier transport behavior with the energy band diagram.
Terahertz intersubband transition in GaN/AlGaN step quantum well
Authors: Wu F. , Tian W. , Yan W. Y. , Zhang J. , Sun S. C. , Dai J. N. , Fang Y. Y. , Wu Z. H. , Chen C. Q.
Published: April 2013

The influences of polarization and structure parameters on the intersubband transition frequency within terahertz (THz) range and oscillator strength in GaN/AlGaN step quantum well have been investigated by solving Schrödinger and Poisson equations self-consistently. The results show that the Al mole compositions of step quantum well and space barrier have a significant effect on the THz intersubband transition frequency. A specific phenomenon is found that the minimum energy spacing between the ground state and first excited state can be achieved as the Al mole composition of space barrier is about twice of that of step well. In particular, an intersubband transition with energy of 19.8 meV (4.83 THz) can be obtained with specifically designed parameters. This specific phenomenon still exists in a wide range of step well width and a narrow range of well width with less than 3% fluctuation of the Al mole composition of barrier. In addition, oscillator strength and dipole matrix element versus the widths of well and step well, the influences of doping location and concentration on the absorption coefficient, are also investigated in detail in this study. The results should be of benefit to the design of devices operating in the THz frequency range.
An energetic model for the direct formation and evolution of nanorings
Authors: Gill S. P. A.
Published: April 2013

The direct transformation of nanoclusters into nanorings has recently been observed during the annealing of Au clusters on an indium-tin-oxide layer [F. Ruffino et al., Appl. Phys. Lett. 98, 023101 (2011)]. The energetic origins of this process are investigated in the context of an analytical model for general heteroepitaxial systems. It is shown that a strained nanocluster (or quantum dot) is metastable and can always reduce its energy by adopting a ring shape as long as the radius of the newly formed ring is above a critical value. This stability constraint requires that part of the wetting layer in the centre of the ring be removed. A very high energy barrier must be surmounted to achieve the morphological change unless the slope of the nanoclusters can increase during the transformation. If this is the case, it is predicted that nanoclusters above a certain size can undergo a barrierless transformation into nanorings. It is found that predicted ring shapes are only consistent with experimental observations if there is a penalty for removal of the substrate. These features indicate why the transformation is possible in some material systems but not others. Once formed nanorings have no equilibrium state and will continue to expand indefinitely. It is predicted that the nanoring population will coarsen (grow) at the expense of any remaining nanoclusters to complete the transformation of the entire system.
Direct patterning of solution-processed organic thin-film transistor by selective control of solution wettability of polymer gate dielectric
Authors: Fujisaki Yoshihide , Ito Hiroshi , Nakajima Yoshiki , Nakata Mitsuru , Tsuji Hiroshi , Yamamoto Toshihiro , Furue Hirokazu , Kurita Taiichiro , Shimidzu Naoki
Published: April 2013

A simple direct patterning method for solution-processable organic semiconductors (OSCs) is demonstrated. The solution-wettable and nonwettable regions of a polymer gate dielectric layer were selectively controlled by a short tetrafluoromethane gas plasma treatment, and we precisely patterned the OSC film in the desired channel region by lamination coating. The patterned OSC films represent polycrystalline structures consisting of crystalline domains varying from 30 to 60 μm, and the resulting short-channel thin-film transistor (TFT) showed a high mobility of up to 1.3 cm2/Vs, a large on/off ratio over 108, and a negligible hysteresis curve. The proposed method is scalable for patterning TFT arrays with large-area dimensions.
Efficient broadband frequency conversion via simultaneous adiabatic three wave mixing processes
Authors: Porat Gil , Arie Ady
Published: April 2013

Two frequency-cascaded and spatially simultaneous three-wave-mixing processes, each pumped by a different frequency, are studied in a quasi-phase-matching crystal with chirped poling. Theory, numerical simulation, and experiment all show that efficient two-process adiabatic frequency conversion takes place over a broad range of input wavelengths. Experimentally, up to five process cascades are obtained. Furthermore, it is demonstrated that reversing the chirp sign results in a different conversion for the same input wavelength. This method can be applied to generation of an all-optically tunable frequency comb.
On-chip measurements of Brownian relaxation of magnetic beads with diameters from 10 nm to 250 nm
Authors: Østerberg Frederik Westergaard , Rizzi Giovanni , Hansen Mikkel Fougt
Published: April 2013

We demonstrate the use of planar Hall effect magnetoresistive sensors for AC susceptibility measurements of magnetic beads with frequencies ranging from DC to 1 MHz. This wide frequency range allows for measuring Brownian relaxation of magnetic beads with diameters ranging from 10 nm to 250 nm. Brownian relaxation is measured for six different magnetic bead types and their hydrodynamic diameters are determined. The hydrodynamic diameters are found to be within 40% of the nominal bead diameters. We discuss the applicability of the different bead types for volume-based biosensing with respect to sedimentation, magnetic trapping, and signal per bead. Among the investigated beads, we conclude that the beads with a nominal diameter of 80 nm are best suited for future on-chip volume-based biosensing experiments using planar Hall effect sensors.
Tunneling conduction in graphene/(poly)vinyl alcohol composite
Authors: Mitra Sreemanta , Banerjee Sourish , Chakravorty Dipankar
Published: April 2013

Graphene/(Poly)vinyl alcohol (PVA) composite film with thickness 60 μm was synthesized by solidification of a PVA solution comprising of dispersed graphene nanosheets. The close proximity of the graphene sheets enables the fluctuation induced tunneling of electrons to occur from one sheet to another. The dielectric data show that the present system can be simulated to a parallel resistance-capacitor network. The high frequency exponent of the frequency variation of the ac conductivity indicates that the charge carriers move in a two-dimensional space. The sample preparation technique will be helpful for synthesizing flexible conductors.
Structural transitions in [001]/[111]-oriented 0.26Pb(In1/2Nb1/2)O3-0.46Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 single crystals probed via neutron diffraction and electrical characterization
Authors: Li Qian , Liu Yun , Wang Jian , Studer Andrew J. , Withers Ray L. , Li Zhenrong , Xu Zhuo
Published: April 2013

We report changes in the metric symmetry of unpoled and electrically poled single crystals of 0.26Pb(In1/2Nb1/2)O3-0.46Pb(Mg1/3Nb2/3)O3-0.28PbTiO3, as revealed by neutron diffraction in conjunction with electrical measurements. The unpoled crystals show relaxor characteristics and an average rhombohedral symmetry that persists from ambient temperature up to the Curie temperature of ∼165 °C. Poling along a [111] direction enhances the rhombohedral distortion away from cubic metric symmetry but appears not to induce any monoclinic phases. By contrast, the poled [001]-oriented crystal has orthorhombic (or monoclinic MC) metric symmetry at 25 °C. An intermediate transition to a metrically tetragonal phase around 120 °C is confirmed for both poled crystals.
Magnetic correlation between La0.7Sr0.3MnO3 and La0.7Sr0.3CoO3 layers in artificial superlattices
Authors: Malik Vivek K. , Hieu Vo Chi , Arenholz Elke , Scholl Andreas , Young Anthony T. , Takamura Yayoi
Published: April 2013

We have probed the interfacial magnetism between La0.7Sr0.3MnO3 (LSMO) and La0.7Sr0.3CoO3 (LSCO) layers in a [LSMO(10 u.c.)/LSCO(10 u.c.)]X6 superlattice (SL) using X-ray magnetic circular dichroism and photoemission electron microscopy. Strong magnetic coupling exists between the LSMO and LSCO layers such that the magnetic domains in both layers have similar size and shape, and they flip their magnetization simultaneously. While 10 u.c. LSCO thin films show no evidence of ferromagnetism, the LSCO layer in the superlattice remains ferromagnetic. Such a modification of magnetic properties is proposed to occur due to strong correlations between the layers along the c-axis of the superlattice.
Enhanced light absorption in thin film solar cells with embedded dielectric nanoparticles: Induced texture dominates Mie scattering
Authors: Nagel James R. , Scarpulla Michael A.
Published: April 2013

We elucidate the dominant physical mechanisms for enhanced light absorption in thin film solar cells with embedded dielectric nanoparticles and conformal surface texturing. A prior work reported enhancement in short-circuit current for such a structure and attributed this gain to increased photon absorption due to Mie scattering by the embedded nanoparticles [S. Nunomura, A. Minowa, H. Sai, and M. Kondo, Appl. Phys. Lett. 97(6), 063507 (2010)]. On the contrary, simulations indicate that absorption gain is categorically dominated by the roughened surface texture that resulted from conformal overgrowth of amorphous silicon above the deposited dielectric nanoparticles.
Macrospin model of precessional spin-transfer-torque switching in planar magnetic tunnel junctions with perpendicular polarizer
Authors: Mejdoubi A. , Lacoste B. , Prenat G. , Dieny B.
Published: April 2013

We developed a macrospin model describing the storage layer magnetization dynamics under spin-transfer-torque (STT) in in-plane magnetized magnetic tunnel junctions comprising a perpendicular, out-of-plane magnetized, polarizer. Two regimes were observed in the storage layer magnetization dynamics under the influence of the two STT contributions originating from the perpendicular polarizer and in-plane reference layer: (i) a regime of steady precession under DC current when the STT from the perpendicular polarizer dominates and (ii) a regime of bipolar switching in a direction determined by the current direction when the STT from the in-plane reference layer dominates.
High performance semitransparent phosphorescent white organic light emitting diodes with bi-directional and symmetrical illumination
Authors: Hong Choi Wing , Lam Tam Hoi , Zhu Furong , Ma Dongge , Sasabe Hisahiro , Kido Junji
Published: April 2013

A semitransparent white organic light-emitting diode (WOLED) is produced based on a blue phosphorescence from iridium(III)[bis(4,6-difuorophenyl)-pyridinato-N,C2] picolinate and an orange phosphorescence from bis(2-(9,9-diethyl-9H-fluoren-2-yl)-1-phenyl-1H-benzoimidazol-N,C3) iridium(acetylacetonate). In this work, a hole-transporting layer of N,N′-diphenyl-N,N′-bis(1-naphthylphenyl)-1,1′-biphenyl-4,4′-diamine (NPB) and an electron-transporting layer of 3,5,3″,5″-tetra-3-pyridyl-[1,1′;3′,1″] terphenyl (B3PyPB) were used. B3PyPB has high electron mobility and a high triplet energy level. The use of B3PyPB helps to reduce the triplet quenching and also to confine the charge recombination in the emissive region of a single-host two-color WOLED. A bi-layer Ag (10 nm)/MoO3 (2.5 nm)-modified indium tin oxide anode and a cathode of Al (1.5 nm)/Ag (15 nm)/NPB (50 nm) were employed. The semitransparent WOLEDs thus developed have perfect symmetrical, bi-directional illumination characteristics, and the weak angular dependent EL emission spectra, which are beneficial for application in planar diffused lighting.
Magnetoresistance based resonance monitoring with pulse-excited planar coils
Authors: Hu Jiafei , Tian Wugang , Zhao Jianqiang , Pan Mengchun , Chen Dixiang , Tian Guiyun , Luo Feilu
Published: April 2013

Magnetoresistance sensing is an attractive resonance monitoring technique for micro/nano-electromechanical systems, due to its merits of simplicity, effectiveness, and independence of capacitance and stress. Nevertheless, the previous schemes suffer from the uncertain magnetic disturbances. In this letter, current pulse based magnetoresistance sensing is proposed to resist this uncertainty. By energizing a pair of planar coils with current pulses, the magnetic disturbances correlated in time can be identified and eliminated in pulse intervals. The detection sensitivity is tunable by varying with the intensity of the pulsed current. Presently, an amplitude detection limit of 0.1 nm/√Hz has been achieved.
Communication: Fullerene resolution by the magnetic circular dichroism
Authors: Štěpánek Petr , Straka Michal , Andrushchenko Valery , Bouř Petr
Published: April 2013

The similarity in shape makes separation and identification of fullerenes difficult. In this work, the magnetic circular dichroism (MCD) spectroscopy is presented as a useful tool for this purpose. Experimental C60 and C70 spectra were obtained and reproduced with the aid of density functional computations and the complex polarization propagator method. Theoretical spectra of other fullerenes revealed distinctive patterns extremely sensitive to molecular structure as well. Requiring tiny amounts of the sample, the MCD technique thus appears as a useful for detailed fullerene studies.
Fabrication and characterization of thermally drawn fiber capacitors
Authors: Lestoquoy Guillaume , Chocat Noémie , Wang Zheng , Joannopoulos John D. , Fink Yoel
Published: April 2013

We report on the fabrication of all-in-fiber capacitors with poly(vinylidene fluoride) (PVDF) as the dielectric material. Electrodes made of conductive polymer are separated by a PVDF thin film within a polycarbonate casing that is thermally drawn into multiple meters of light-weight, readily functional fiber. Capacitive response up to 20 kHz is measured and losses at higher-frequencies are accounted for in a materials-based model. A multilayered architecture in which a folded PVDF film separates interdigitated electrodes over an increased area is fabricated. This structure greatly enhances the capacitance, which scales linearly with the fiber length and is unaffected by fiber dimension fluctuations.
Thin Ni film on graphene current spreading layer for GaN-based blue and ultra-violet light-emitting diodes
Authors: Shim Jae-Phil , Hoon Seo Tae , Min Jung-Hong , Mo Kang Chang , Suh Eun-Kyung , Lee Dong-Seon
Published: April 2013

We introduced a thin nickel (Ni) film onto graphene as a current spreading layer for GaN-based blue and ultraviolet (UV) light emitting diodes (LEDs). The thin Ni film was confirmed to improve the electrical properties of the graphene by reducing the sheet and contact resistances. The advantages of Ni on graphene were more remarkable in UV LEDs, in which the operation voltage was reduced from 13.2 V for graphene alone to 7.1 V. As a result, UV LEDs with Ni on graphene showed a uniform and reliable light emission, at ∼83% of electroluminescence of indium tin oxide.
Electron emission from a two-dimensional crystal with atomic thickness
Authors: Wei Xianlong , Chen Qing , Peng Lianmao
Published: April 2013

Electron emission from a two-dimensional (2D) crystal with atomic thickness is theoretically studied with all the features associated with the low dimensionality and the atomic thickness being well considered. It is shown that, the atomic thickness results in quantum confinement of electrons in the crystal along thickness direction, and consequently two different ways of electron emission from it without and with quantum confinement of electrons normal to emission boundary: edge emission and surface emission. While electron emission from the edge of a 2D crystal can be described by the existing model,electron emission from the surface goes beyond its reach. Here, to describe the latter electron emission, a model based on the energy band theory with the quantum confinement along thickness direction being considered is proposed. It is shown that, the proposed model is a general one capable of describing not only electron emission with quantum confinement normal to an emission boundary but also electron emission without the regarded quantum confinement. The model is expected to advance the understanding and description of electron emission from a solid.
Shared Space, Divided Space: Narrating Ethnic Histories of Osh
Authors: Megoran Nick
Published: April 2013

In June 2010 the Kyrgyzstani city of Osh was engulfed in three days of mass killing, arson, and looting. Accounts by journalists, academics, politicians, and organisations tend to either overdetermine ethnicity as a causal factor, or dismiss its significance as a social process. As a result, internal responses to the tragedy have been viewed by outsiders as mendaciously irrational. To overcome this impasse, this paper foregrounds the idea of Osh as national territory. Based on ongoing ethnographic study since 1995, plus an analysis of media reports, it shows the ways in which Uzbek and Kyrgyz residents of the city have narrated its ethnic past as one of divided or shared space. The resonance of these narratives can both help account for responses to the violence within Kyrgyzstan that have puzzled outsiders, and also uncover resources of hope. The paper highlights the importance of considering nationalism as a geographical phenomenon in explicating ethnic-based violence in contemporary Central Asia.
Religious Residential Segregation and Internal Migration: The British Muslim Case
Authors: Gale Richard
Published: April 2013

Concerns over British Muslim integration have been to the fore of public debate over much of the last decade, with Muslim segregation constituting a key issue. Recent analyses have usefully shown that current concerns over segregation levels in the UK are exaggerated. However, these analyses continue to rely on census ethnicity data, which are used as proxy for religion to draw inferences about Muslim residential phenomena. Focusing on Birmingham, this paper redresses this tendency by using religion data to explore religious segregation directly. Adopting established measures of segregation and Special Migration Statistics (SMS) by religion for the year 2000/01, the paper shows that, whilst Muslim segregation in Birmingham is high, there has been a significant if spatially constrained movement away from concentrated inner urban areas.
Social Capital and the Innovative Performance of Italian Provinces
Authors: Crescenzi Riccardo , Gagliardi Luisa , Percoco Marco
Published: April 2013

Social capital has remained relatively underexplored in innovation literature due to the lack of consensus on the most suitable operationalisation for the analysis of innovative dynamics. This paper aims to fill this gap by looking at social capital as propensity towards civicness and prosocial behaviour that facilitates the circulation of nonredundant knowledge among otherwise disconnected groups. The quantitative analysis of the innovative performance of Italian provinces shows that social capital—proxied by blood donations and participation into voluntary associations—is an important predictor of innovative performance after controlling for ‘traditional’ knowledge inputs (R&D and human capital). In addition, instrumental variable analysis makes it possible to identify clear causal links between social capital and innovation, suggesting that social norms play an important role in shaping the incentives for knowledge generation, circulation, and accumulation.
The Making of a Void Sovereignty: Political Implications of the Military Checkpoints in the West Bank
Authors: Amir Merav
Published: April 2013

Research on the Israeli checkpoints in the West Bank has emphasized not only that these checkpoints have dire implications for the Palestinians living there, at the personal, familial, and communal levels, and devastating effects on the Palestinian economy, but also that they have far-reaching consequences for the ability of the Palestinians to establish an independent political entity. At the same time, analysis of the Israeli forms of domination over the Palestinians has also stressed the role of a Palestinian governing authority in sustaining the Israeli rule, since the former relieves the latter of its responsibility to care for the occupied Palestinian population. This paper aims to address this apparent contradiction claiming that a comprehensive analysis of Israeli forms of domination requires a spatial examination of the operation of sovereignty with an assessment of governmentalizing arrays. This combined analysis suggests that a Palestinian sovereignty, but one which is emptied of its actual ruling power, is construed at the checkpoints as an epiphenomenon of Israeli apparatuses of control.
Water, Power, and the Production of Neoliberalism in Chile, 1973–2005
Authors: Budds Jessica
Published: April 2013

Chile's free-market economic and political reforms, designed and implemented under General Pinochet's military regime (1973–90), have been important in discussions of neoliberal public policy and environmental governance. However, understandings of how and why these reforms unfolded often overlook the complex power dynamics involved. This paper examines the role of water in consolidating the design, implementation, and outcomes of Chile's neoliberal programme, through the contested production, retention, and reform of the 1981 Water Code. Drawing on the idea that water and power are mutually constitutive, it demonstrates the significance of the transition to private tradable water rights with minimal state regulation not only for changing social relationships with water, but also for consolidating the neoliberal programme and the ambitions of the military regime, government technocrats, and business groups. I make three related arguments: first, that water was more central to the formation and effectiveness of the neoliberal programme in Chile, and the ambitions of its core supporters than hitherto acknowledged; second, that political interest groups, and their alliances, can play crucial roles in neoliberalising nature; and third, that water reforms consolidate power relationships and produce waterscapes in particular ways.
Ensiling corn silage with different levels of a multi-species lactic acid bacteria inoculant
Authors: Mohammadzadeh H. , Khorvash M. , Ghorbani G. R.
Published: April 2013

A multi-species lactic acid bacterial inoculant (Lactisil maize, LM) was applied to whole-crop corn at different maturities in laboratory silos, to evaluate its effects on biochemical characteristics and aerobic stability. The corn crop was harvested at hard dough (HD, 253.1 g/DM kg), one-third milkline (ML, 293.7 g/DM kg) and one-third milkline with a killing frost (MLF, 297.6 g/DM kg). Crops were chopped to a 2.5-cm theoretical cut length, subsampled and treated with two levels of inoculant (LB1 = 1.5 × 105 cfu/g forage, LB2 = 3 × 105 cfu/g forage) or untreated (WO). The chemical composition of MLF crops was very similar to that of ML crops. However, lower (P < 0.01) numbers of lactic acid bacteria and higher numbers of yeast were enumerated in MLF than in ML crops. Higher percentages of DM and neutral detergent fibre and higher pH, but lower (P < 0.01) concentrations of water soluble carbohydrate and crude protein were measured in ML and MLF crops than in HD crops. Application of the inoculant increased (P < 0.01) concentrations of volatile fatty acids, neutral detergent fibre and acid detergent fibre in silages. Lactic acid concentration increased (P < 0.01) in HD treatments with an increasing level of inoculant. In contrast, the highest (P < 0.01) lactic acid concentration was measured in LB1 treatment compared with WO and LB2 in ML and MLF silages. Silages prepared from ML and MLF crops had higher (P < 0.01) lactic and acetic acid concentrations but lower (P < 0.01) butyric acid concentrations than did those prepared from HD. The pH in LB1 and LB2 silages was higher (P < 0.01) than that measured in WO silages. Aerobic stability was not influenced by inoculant treatment but low-DM silages were more (P < 0.01) resistant to spoilage. Frost-killed corn crops had a good potential to produce well fermented silage. Using LM resulted in silages with slightly higher fermentation products but it failed to improve aerobic stability of silage after 120 days of ensiling. These results indicated that inoculation of corn crops with LM for a short-duration ensilage period cannot enhance aerobic stability of silages due to insufficient acetic acid production from lactic acid conversion.
Performance, return and risk of different dairy systems in Australia and New Zealand
Authors: Ho C. K. M. , Newman M. , Dalley D. E. , Little S. , Wales W. J.
Published: April 2013

Changes in the farm operating and policy environments and a need to remain profitable under a cost-price squeeze have contributed to dairy systems in Australia and New Zealand becoming more intensive and complex in recent decades. Farm systems in both countries are now diverse, varying from being based predominantly on pasture with little purchased supplements, to those dependent on high levels of feed supplements and even having zero grazing. Dairy farm performance (defined in this paper as production or technical performance), return (return on assets or profit) and risk (variation in economic performance over time), and intensity of dairy systems was examined using farm survey data, case studies and existing published studies. The level of single technical performance measures, such as milk production, feed conversion efficiency and pasture consumption, prevailing in a business are not guides to the operating profit and return on assets of a business. In addition, when survey data of farm performance was grouped by return on assets, few farms were in the top 25% in successive years. Farms that performed consistently well were characterised by good, but not extreme, technical performance in a range of key areas, which translated to favourable business return (return on asset and profit). The knowledge and skills of farm managers are critical, and means that many different dairy systems can perform well physically and financially and successfully meet farmer goals. The relation between risk and the intensity of dairy systems was also investigated. Options that intensified systems generally resulted in higher net wealth for the farm owner, but almost always at increased risk. The best system for any farmer to operate is one which best meets their multifaceted preferences and goals, regardless of system type.
The mixotrophic nature of photosynthetic plants
Authors: Schmidt Susanne , Raven John A. , Paungfoo-Lonhienne Chanyarat
Published: April 2013

Plants typically have photosynthetically competent green shoots. To complement resources derived from the atmospheric environment, plants also acquire essential elements from soil. Inorganic ions and molecules are generally considered to be the sources of soil-derived nutrients, and plants tested in this respect can grow with only inorganic nutrients and so can live as autotrophs. However, mycorrhizal symbionts are known to access nutrients from organic matter. Furthermore, specialist lineages of terrestrial photosynthetically competent plants are mixotrophic, including species that obtain organic nutrition from animal prey (carnivores), fungal partners (mycoheterotrophs) or plant hosts (hemi-parasites). Although mixotrophy is deemed the exception in terrestrial plants, it is a common mode of nutrition in aquatic algae. There is mounting evidence that non-specialist plants acquire organic compounds as sources of nutrients, taking up and metabolising a range of organic monomers, oligomers, polymers and even microbes as sources of nitrogen and phosphorus. Plasma-membrane located transporter proteins facilitate the uptake of low-molecular mass organic compounds, endo- and phagocytosis may enable the acquisition of larger compounds, although this has not been confirmed. Identifying the mechanisms involved in the acquisition of organic nutrients will provide understanding of the ecological significance of mixotrophy. Here, we discuss mixotrophy in the context of nitrogen and phosphorus nutrition drawing parallels between algae and plants.
Mechanism of tyrosine D oxidation in Photosystem II
Authors: Saito Keisuke , Rutherford A. William , Ishikita Hiroshi
Published: April 2013

Using quantum mechanics/molecular mechanics calculations and the 1.9-Å crystal structure of Photosystem II [Umena Y, Kawakami K, Shen J-R, Kamiya N (2011)Nature473(7345):55–60], we investigated the H-bonding environment of the redox-active tyrosine D (TyrD) and obtained insights that help explain its slow redox kinetics and the stability of TyrD•. The water molecule distal to TyrD, located ∼4 Å away from the phenolic O of TyrD, corresponds to the presence of the tyrosyl radical state. The water molecule proximal to TyrD, in H-bonding distance to the phenolic O of TyrD, corresponds to the presence of the unoxidized tyrosine. The H+released on oxidation of TyrD is transferred to the proximal water, which shifts to the distal position, triggering a concerted proton transfer pathway involving D2-Arg180 and a series of waters, through which the proton reaches the aqueous phase at D2-His61. The water movement linked to the ejection of the proton from the hydrophobic environment near TyrD makes oxidation slow and quasiirreversible, explaining the great stability of the TyrD•. A symmetry-related proton pathway associated with tyrosine Z is pointed out, and this is associated with one of the Cl−sites. This may represent a proton pathway functional in the water oxidation cycle.
Genome-wide diel growth state transitions in the diatom
Thalassiosira pseudonana
Authors: Ashworth Justin , Coesel Sacha , Lee Allison , Armbrust E. Virginia , Orellana Mónica V. , Baliga Nitin S.
Published: April 2013

Marine diatoms are important primary producers that thrive in diverse and dynamic environments. They do so, in theory, by sensing changing conditions and adapting their physiology accordingly. Using the model species
Thalassiosira pseudonana
, we conducted a detailed physiological and transcriptomic survey to measure the recurrent transcriptional changes that characterize typical diatom growth in batch culture. Roughly 40% of the transcriptome varied significantly and recurrently, reflecting large, reproducible cell-state transitions between four principal states: (
i
) “dawn,” following 12 h of darkness; (
ii
) “dusk,” following 12 h of light; (
iii
) exponential growth and nutrient repletion; and (
iv
) stationary phase and nutrient depletion. Increases in expression of thousands of genes at the end of the reoccurring dark periods (dawn), including those involved in photosynthesis (e.g., ribulose-1,5-bisphosphate carboxylase oxygenase genes
rbcS
and
rbcL
), imply large-scale anticipatory circadian mechanisms at the level of gene regulation. Repeated shifts in the transcript levels of hundreds of genes encoding sensory, signaling, and regulatory functions accompanied the four cell-state transitions, providing a preliminary map of the highly coordinated gene regulatory program under varying conditions. Several putative light sensing and signaling proteins were associated with recurrent diel transitions, suggesting that these genes may be involved in light-sensitive and circadian regulation of cell state. These results begin to explain, in comprehensive detail, how the diatom gene regulatory program operates under varying environmental conditions. Detailed knowledge of this dynamic molecular process will be invaluable for new hypothesis generation and the interpretation of genetic, environmental, and metatranscriptomic data from field studies.
FURTHER EXAMINATION OF GIBBERELLIN A, EFFECTS ON FLOWERING OF GLOBE ARTICHOKES (CYNARA SCOLYMUS L.) UNDER CONTROLLED ENVIRONMENT AND FIELD CONDITIONS
Authors: Basnizki Jehuda , Goldschmidt Eliezer E.
Published: April 2013

The effect of gibberellin A3(GA3) treatments on flowering of seed-grown globe artichoke (Cynara scolymus)was investigated under controlled environment and field conditions. GA3induced flower initiation in lines ‘060’ and ‘Talpiot’ under strictly noninductive, short-day-high-temperature conditions. In ‘Talpiot’, GA3induced microscopically detectable flower initiation but no stem elongation, suggesting involvement of gibberellins in the flower formation process. Under field conditions, GA3replaced the cold requirements of line ‘HU 271’, thereby enabling the start of flowering during autumn. The vegetative clone Bianca d'Espana flowered during autumn without GA3treatment, probably due to its minimum cold requirements. Definition of the response type and the role of gibberellins in the flowering of globe artichoke are discussed.
LONG-TERM SEED POSITION INFLUENCES ON SEED GERMINABILITY OF THE DESERT ANNUAL, MESEMBRYANTHEMUM NODIFLORUM L.
Authors: Gutterman Yitzchak
Published: April 2013

DryMesembryanthemum nodiflorumL. plants containing mature seeds in their capsules were harvested in summer 1972 and stored. Seeds separated from the capsules were tested for germination over more than two decades. In each capsule there are three groups of about 10 seeds each: terminal, central, and basal seeds. These are dispersed after different periods of wetting and also display differing germinability, even after 22 years of storage. The terminal seeds germinate to the highest and the basals to the lowest level at 10 to 30 °C. Germination of all three groups of seeds in the dark was higher than in light. After wetting at 30 °C, in the dark, the basal seeds germinated to the highest percentage. Even after 57 days of wetting, depending on the seed position in the capsule and environmental factors during wetting, seeds germinated in the range from 14 to 64%. Together with environmental influences during the time of wetting, the long-living seeds with long-term position effects on the low percentage of germination of theM. nodiflorumseed population are discussed.
EFFECTS OF INDIVIDUAL AND COMBINED INOCULATION OF MELOIDOGYNE JAVANICA, RHIZOCTONIA SOLANI, AND FUSARIUM OXYSPORUM F. SP. CICERI ON CHICKPEA
Authors: Fazal Munawar , Khan M.Imran , Raza M. Ashaq , A. Siddiqui Ziauddin
Published: April 2013

The effects of Meloidogyne javanica, Rhizoctonia solani, and Fusarium oxysporum f. sp. ciceri, both singly and in various combinations, on chickpea (Cicer arietinum) were studied. Singly, F. oxysporum f. sp. ciceri was the most aggressive pathogen. In concomitant inoculations, reduction in growth parameter was greater than the sum total of reductions caused by the pathogens alone. All three pathogens adversely affected nodulation singly as well as in concomitant inoculations, and reduction in nodulation followed a similar trend as plant growth. Rate of nematode multiplication and galling was significantly reduced in the presence of fungus.
CONTRIBUTIONS TO THE FLORA OF ISRAEL. VII. BROMUS COMMUTATUS SCHRADER, AEGILOPS CYLINDRICA HOST, AND VULPIA PERSICA (BOISS. ET BUHSE) V. KRECZ. ET BOBROV, NEW GRASSES IN ISRAEL
Authors: Danin Avinoam , Scholz Hildemar
Published: April 2013

Two adventive grasses, Bromus commutatus and Aegilops cylindrica, were discovered growing at roadsides in Jerusalem. The two weedy species are known from moister areas and are recorded here for the first time from Israel. Vulpia persica is a plant of Irano-Turanian steppes which was found in a natural habitat in the Negev Highlands. Their distribution and habitats are discussed.
COMBINED IRRIGATION AND FERTILIZATION IN ARID ZONES
Authors: Kafkafi Uzi
Published: April 2013

Sand dunes and highly calcareous soils occupy vast areas in arid zones. The soils are characterized by low available nutrient content and low to medium water-holding capacity of the upper soil surface. These features result in low vegetation density under arid climate conditions. The introduction of trickle irrigation coupled with liquid fertilizers turned desert sand dunes and highly calcareous soils into productive agricultural soils for high cash crops. The intensity of daily nutrient supply dictates the farmer's consideration of the form of nitrogen supplied to the crop and to the variable sensitivity of plants to the different forms of N supplied by various fertilizers through the irrigation system. The combination of high root temperature and high ammonium concentration is of particular importance. Plants that have relatively low carbohydrate content in their roots might suffer from ammonia toxicity if a high daily supply of ammonium is available. High concentrations of urea and very high calcium carbonate content in the soil are also dangerous to ammonium- sensitive plants like tomatoes. Planning the irrigation system and nutrient supply to the crops according to their physiological stage of development, and consideration of the soil and climate characteristics, can give high yields and high quality crops with minimum pollution, but salt accumulation on the soil surface should be prevented, either by sprinkle irrigation, or by plastic mulch during the growing season.
HYDRAULIC LIFT AND SOIL NUTRIENT HETEROGENEITY
Authors: Caldwell Martyn M. , Manwaring John H.
Published: April 2013

Water released at night from roots into upper portions of the soil profile in the process of hydraulic lift may contribute to reducing spatial soil nutrient heterogeneity. A manipulative field experiment was conducted in a semiarid shrub stand to determine if circumvention of hydraulic lift, by nighttime illumination of the shrub canopy, would result in greater soil nutrient heterogeneity than if the hydraulic lift process was allowed to operate. Nutrient-enriched patches were superimposed on the existing soil heterogeneity and after 40 days, the patches and interspaces were sampled for ions of different mobility and for root mass. There was no indication under these conditions that hydraulic lift was contributing to smoothing spatial nutrient heterogeneity.