bluuebunny/crossref_metadata_2025 huggingface dataset:
Indonesia's Postcolonial Regional Imaginary: From a ‘Neutralist’ to an ‘All-Directions’ Foreign Policy
Authors: CLARK MARSHALL
Published: June 2011

This paper will examine the various ways in which the regional imaginary has been conceptualized and developed in maritime Southeast Asia, primarily focussing on Indonesia. Utilizing the recent debate on the notion of a ‘Postcolonial International Relations,’ this paper examines the role of imperialism and the colonial experience on the development of Indonesian ‘ideas’ of region and regionalism. This paper is structured into four sections. First of all, it explores the link between postcolonial theory and regionalism studies. Second, it takes into account early ideas of regionalism in the post-independence era. This includes President Sukarno's ‘neutralist’ foreign policy culminating in Indonesia's hosting of the Bandung Conference as well as President Suharto's endorsement of ASEAN. The third and final section examines Indonesia's foreign policy orientation and practices in the post-authoritarian period, particularly under President Susilo Bambang Yudhoyono. With its embrace of democracy in the post-New Order era, the concluding discussion suggests that Indonesia appears to be increasingly prepared to expand its regional engagement concentrically beyond the immediate Southeast Asian region. The question of the ‘imperial’ role of the US – which has its own foreign policy ambitions in the region – is instrumental in this regard, and can be usefully understood from a postcolonial framework.
Motivated Processing of Fear Appeal and Disgust Images in Televised Anti-Tobacco Ads
Authors: Leshner Glenn , Bolls Paul , Wise Kevin
Published: June 2011

The current study experimentally tested the effects of two types of content commonly found in anti-tobacco television messages – content focused on communicating a health threat about tobacco use (fear) and content containing disgust related images – on how viewers processed these messages. In a 2 × 2 within-subjects experiment, participants watched anti-tobacco television ads that varied in the amount of fear and disgust content. The results of this study suggest that both fear and disgust content in anti-tobacco television ads have significant effects on resources allocated to encoding the messages, on recognition memory, and on emotional responses. Most interesting, although messages high in both fear and disgust content were rated the most unpleasant and arousing, these same messages reduced corrugator responses, accelerated heart rate, and worsened recognition memory. Implications for the study of motivated processing and for the construction of anti-tobacco messages are discussed.
The Caribbean–North America–Cocos Triple Junction and the dynamics of the Polochic–Motagua fault systems: Pull‐up and zipper models
Authors: Authemayou C. , Brocard G. , Teyssier C. , Simon‐Labric T. , Guttiérrez A. , Chiquín E. N. , Morán S.
Published: June 2011

The Polochic‐Motagua fault systems (PMFS) are part of the sinistral transform boundary between the North American and Caribbean plates. To the west, these systems interact with the subduction zone of the Cocos plate, forming a subduction‐subduction‐transform triple junction. The North American plate moves westward relative to the Caribbean plate. This movement does not affect the geometry of the subducted Cocos plate, which implies that deformation is accommodated entirely in the two overriding plates. Structural data, fault kinematic analysis, and geomorphic observations provide new elements that help to understand the late Cenozoic evolution of this triple junction. In the Miocene, extension and shortening occurred south and north of the Motagua fault, respectively. This strain regime migrated northward to the Polochic fault after the late Miocene. This shift is interpreted as a “pull‐up” of North American blocks into the Caribbean realm. To the west, the PMFS interact with a trench‐parallel fault zone that links the Tonala fault to the Jalpatagua fault. These faults bound a fore‐arc sliver that is shared by the two overriding plates. We propose that the dextral Jalpatagua fault merges with the sinistral PMFS, leaving behind a suturing structure, the Tonala fault. This tectonic “zipper” allows the migration of the triple junction. As a result, the fore‐arc sliver comes into contact with the North American plate and helps to maintain a linear subduction zone along the trailing edge of the Caribbean plate. All these processes currently make the triple junction increasingly diffuse as it propagates eastward and inland within both overriding plates.
Hypoxic exercise training promotes antitumour cytotoxicity of natural killer cells in young men
Authors: Wang Jong-Shyan , Weng Tzu-Pin
Published: June 2011

The cytotoxic functions of NKs (natural killer cells) are critical in enabling the immune system to cope efficiently with malignancy. In the present study, we compared how various exercise regimens without/with hypoxia influence phenotypic characteristics of NK subsets and cytotoxicity of NKs to NPCs (nasopharyngeal carcinoma cells). A total of 60 sedentary males were randomly divided into five groups. Each group (n=12) underwent one of five regimens: normoxic (21% O2) control (N-C), hypoxic (15% O2) control (H-C), normoxic exercise (50% maximal work rate under 21% O2; N-E), hypoxic relative exercise (50% maximal heart rate reserve under 15% O2; H-RE) or hypoxic absolute exercise (50% maximal work rate under 15% O2; H-AE) for 30 min/day, 5 days/week for 4 weeks. The results showed that hypoxic exercise regimens increased pulmonary ventilation and tissue oxygen utilization. Moreover, the H-RE regimen resulted in enhanced aerobic fitness at a less intensive training workload in the H-AE regimen. Before each regimen, strenuous exercise elevated NK perforin/granzyme B content and promoted cytotoxicity of NKs to NPCs. However, the percentage of NKs expressing homing (CD11a)/terminally differentiated (CD57)/inhibitory [KLRG1 (killer cell lectin-like receptor G1)] molecules that entered the bloodstream from peripheral tissues increased following this exercise. After 4 weeks, both the H-AE and H-RE regimens produced an up-regulated expression of memory (CD45RO)/activating (NKG2D) molecules and was accompanied by a decrease in CD57/KLRG1 levels on NKs at rest and after strenuous exercise. Furthermore, the two regimens increased resting and exercise NK perforin/granzyme B content and NK-induced phosphatidylserine exposure of NPCs. In contrast, no significant change in the phenotypic characteristics of blood NK subsets or NK-induced NPC apoptosis was observed in the N-C, H-C and N-E regimens. Therefore we conclude that 15% O2 exercise training reduces terminally differentiated NK subsets and up-regulates the expression of activating molecules and cytotoxic granule proteins in NKs, thereby enhancing the capacity of anti-NPC cytotoxicity by NKs. These findings could help to determine effective hypoxic exercise regimens for improving individual aerobic capacity and simultaneously promoting the natural cytotoxicity of NKs.
ZnO Schottky barriers and Ohmic contacts
Authors: Brillson Leonard J. , Lu Yicheng
Published: June 2011

ZnO has emerged as a promising candidate for optoelectronic and microelectronic applications, whose development requires greater understanding and control of their electronic contacts. The rapid pace of ZnO research over the past decade has yielded considerable new information on the nature of ZnO interfaces with metals. Work on ZnO contacts over the past decade has now been carried out on high quality material, nearly free from complicating factors such as impurities, morphological and native point defects. Based on the high quality bulk and thin film crystals now available, ZnO exhibits a range of systematic interface electronic structure that can be understood at the atomic scale. Here we provide a comprehensive review of Schottky barrier and ohmic contacts including work extending over the past half century. For Schottky barriers, these results span the nature of ZnO surface charge transfer, the roles of surface cleaning, crystal quality, chemical interactions, and defect formation. For ohmic contacts, these studies encompass the nature of metal-specific interactions, the role of annealing, multilayered contacts, alloyed contacts, metallization schemes for state-of-the-art contacts, and their application to n-type versus p-type ZnO. Both ZnO Schottky barriers and ohmic contacts show a wide range of phenomena and electronic behavior, which can all be directly tied to chemical and structural changes on an atomic scale.
Optimal use of data in parallel tempering simulations for the construction of discrete-state Markov models of biomolecular dynamics
Authors: Prinz Jan-Hendrik , Chodera John D. , Pande Vijay S. , Swope William C. , Smith Jeremy C. , Noé Frank
Published: June 2011

Parallel tempering (PT) molecular dynamics simulations have been extensively investigated as a means of efficient sampling of the configurations of biomolecular systems. Recent work has demonstrated how the short physical trajectories generated in PT simulations of biomolecules can be used to construct the Markov models describing biomolecular dynamics at each simulated temperature. While this approach describes the temperature-dependent kinetics, it does not make optimal use of all available PT data, instead estimating the rates at a given temperature using only data from that temperature. This can be problematic, as some relevant transitions or states may not be sufficiently sampled at the temperature of interest, but might be readily sampled at nearby temperatures. Further, the comparison of temperature-dependent properties can suffer from the false assumption that data collected from different temperatures are uncorrelated. We propose here a strategy in which, by a simple modification of the PT protocol, the harvested trajectories can be reweighted, permitting data from all temperatures to contribute to the estimated kinetic model. The method reduces the statistical uncertainty in the kinetic model relative to the single temperature approach and provides estimates of transition probabilities even for transitions not observed at the temperature of interest. Further, the method allows the kinetics to be estimated at temperatures other than those at which simulations were run. We illustrate this method by applying it to the generation of a Markov model of the conformational dynamics of the solvated terminally blocked alanine peptide.
Gravity from the extension of spatial diffeomorphisms
Authors: Farkas Szilard , Martinec Emil J.
Published: June 2011

The possibility of the extension of spatial diffeomorphisms to a larger family of symmetries in a class of classical field theories is studied. The generator of the additional local symmetry contains a quadratic kinetic term and a potential term which can be a general (not necessarily local) functional of the metric. From the perspective of the foundation of Einstein's gravity our results are positive: The extended constraint algebra is either that of Einstein's gravity or ultralocal gravity. If our goal is a simple modification of Einstein's gravity that for example makes it perturbatively renormalizable, as has recently been suggested, then our results show that there is no such theory within this class.
Effects of small-scale freestream turbulence on turbulent boundary layers with and without thermal convection
Authors: Nagata Kouji , Sakai Yasuhiko , Komori Satoru
Published: June 2011

Effects of weak, small-scale freestream turbulence on turbulent boundary layers with and without thermal convection are experimentally investigated using a wind tunnel. Two experiments are carried out: the first is isothermal boundary layers with and without grid turbulence, and the second is non-isothermal boundary layers with and without grid turbulence. Both boundary layers develop under a small favorable pressure gradient. For the latter case, the bottom wall of the test section is heated at a constant wall temperature to investigate the effects of thermal convection under the effects of freestream turbulence. For both cases, the turbulence intensity in the freestream is Tu = 1.3% ∼ 2.4%, and the integral length scale of freestream turbulence, L∞, is much smaller than the boundary layer thickness δ, i.e., L∞/δ≪1. The Reynolds numbers Reθ based on the momentum thickness and freestream speed U∞ are Reθ = 560, 1100, 1310, and 2330 in isothermal boundary layers without grid turbulence. Instantaneous velocities, U and V, and instantaneous temperature T are simultaneously measured using a hot-wire anemometry and a constant-current resistance thermometer. The results show that the rms velocities and Reynolds shear stress normalized by the friction velocity are strongly suppressed by the freestream turbulence throughout the boundary layer in both isothermal and non-isothermal boundary layers. In the non-isothermal boundary layers, the normalized rms temperature and vertical turbulent heat flux are also strongly suppressed by the freestream turbulence. Turbulent momentum and heat transfer at the wall are enhanced by the freestream turbulence and the enhancement is notable in unstable stratification. The power spectra of u, v, and θ and their cospectra show that motions of almost all scales are suppressed by the freestream turbulence in both the isothermal and non-isothermal boundary layers.
Development of a plasma generator for a long pulse ion source for neutral beam injectors
Authors: Watanabe K. , Dairaku M. , Tobari H. , Kashiwagi M. , Inoue T. , Hanada M. , Jeong S. H. , Chang D. H. , Kim T. S. , Kim B. R. , Seo C. S. , Jin J. T. , Lee K. W. , In S. R. , Oh B. H. , Kim J. , Bae Y. S.
Published: June 2011

A plasma generator for a long pulse H+/D+ ion source has been developed. The plasma generator was designed to produce 65 A H+/D+ beams at an energy of 120 keV from an ion extraction area of 12 cm in width and 45 cm in length. Configuration of the plasma generator is a multi-cusp bucket type with SmCo permanent magnets. Dimension of a plasma chamber is 25 cm in width, 59 cm in length, and 32.5 cm in depth. The plasma generator was designed and fabricated at Japan Atomic Energy Agency. Source plasma generation and beam extraction tests for hydrogen coupling with an accelerator of the KSTAR ion source have been performed at the KSTAR neutral beam test stand under the agreement of Japan-Korea collaborative experiment. Spatial uniformity of the source plasma at the extraction region was measured using Langmuir probes and ±7% of the deviation from an averaged ion saturation current density was obtained. A long pulse test of the plasma generation up to 200 s with an arc discharge power of 70 kW has been successfully demonstrated. The arc discharge power satisfies the requirement of the beam production for the KSTAR NBI. A 70 keV, 41 A, 5 s hydrogen ion beam has been extracted with a high arc efficiency of 0.9 −1.1 A/kW at a beam extraction experiment. A deuteron yield of 77% was measured even at a low beam current density of 73 mA/cm2.
Extraordinary transmission through a silver film perforated with bowtie-shaped aperture array in midinfrared region
Authors: Huang Shao-Yu , Hsiao Hui-Hsin , Chang Yi-Tsung , Chen Hung-Hsin , Jiang Yu-Wei , Huang Hao-Fu , Chang Pei-En , Chang Hung-Chun , Lee Si-Chen
Published: June 2011

The transmission spectra of bowtie aperture consisting of opposing triangular holes arranged in rectangular array on silver/silicon structure were investigated. It is found that the second order surface plasmon polaritons mode is much stronger than the fundamental one. In addition, by increasing the separation and angles of the tips or silver film thickness, the second order modes decrease gradually. These phenomena suggest magnetic field coupling between metal tips which results in higher order mode enhancement.
Refractive index of lithium fluoride ramp compressed to 800 GPa
Authors: Fratanduono D. E. , Boehly T. R. , Barrios M. A. , Meyerhofer D. D. , Eggert J. H. , Smith R. F. , Hicks D. G. , Celliers P. M. , Braun D. G. , Collins G. W.
Published: June 2011

We report the highest pressure under which a transparent insulator has been observed. The refractive index of ramp-compressed lithium fluoride (LiF) is measured up to a pressure of 800 GPa and is observed to maintain its linear dependence on density. An effective single-oscillator model infers that the bandgap monotonically closes with increasing density, indicating that metallization of LiF should occur at pressures above 4000 GPa, and that LiF should remain transparent at extremely high pressures.
Photoreflectance and photoluminescence studies of epitaxial InGaAs quantum rods grown with As2 and As4 sources
Authors: Nedzinskas R. , Čechavičius B. , Karpus V. , Kavaliauskas J. , Valušis G. , Li L. H. , Khanna S. P. , Linfield E. H.
Published: June 2011

Photoreflectance spectroscopy and photoluminescence (PL) have been used to explore the optical properties and electronic structure of InGaAs quantum rods (QRs) grown by molecular beam epitaxy. Different As sources — As2 and As4 — were used during epitaxial growth in order to evaluate their effect on the optical properties of the nanostructures. Spectral features associated with interband optical transitions taking place in the QR and the surrounding quantum well (QW) regions are examined. A redshift of the QR- and a blueshift of the QW-related optical transitions, along with a significant increase in PL intensity, have been observed if an As4 source is used. These changes in optical properties are mainly attributed to quantum confinement effects related to a variation of indium content in the QR and QW regions.
Global conservative and dissipative solutions of a coupled Camassa-Holm equations
Authors: Tian Lixin , Wang Yujuan , Zhou Jiangbo
Published: June 2011

This paper develops a new approach in the analysis of a coupled Camassa-Holm equations. A continuous semigroup of global conservative solutions and a continuous semigroup of global dissipative solutions are obtained, respectively. The solutions are conservative, in the sense that the total energy equals to a constant, for almost every time. While the solutions are dissipative, in the sense that energy loss occurs through wave breaking. Compared to the approaches used by Bressan, A. and Constantin, A., “Global conservative solutions of the Camassa-Holm equation,” Arch. Ration. Mech. Anal. 183, 215–239 (2007)10.1007/s00205-006-0010-z and Bressan, A. and Constantin, A., “Global dissipative solutions of the Camassa–Holm equation,” Anal. Appl. (Singapore) 5, 1–27 (2007)10.1142/S0219530507000857 for the Camassa-Holm equation, two characteristics are introduced and a new set of independent and dependent variables are applied to the coupled Camassa-Holm equations.
Thermally exfoliated graphene based counter electrode for low cost dye sensitized solar cells
Authors: Kaniyoor Adarsh , Ramaprabhu Sundara
Published: June 2011

Graphene obtained from thermal exfoliation of graphite oxide are highly wrinkled and have large surface area. Their wrinkled nature is expected to give them excellent catalytic activity. Herein, we demonstrate the use of thermally exfoliated graphene (TEG) as cost effective electrocatalyst for the tri-iodide reduction in dye sensitized solar cells (DSSCs). X-ray diffraction, Raman and Infra red spectroscopy and electron microscopy studies confirm the defective and wrinkled nature of TEG. BET surface area measurement show a large surface area of ∼ 470 m2/g. The counter electrode was fabricated by drop casting a slurry of TEG dispersed in a Nafion:Ethanol solution on fluorine doped tin oxide (FTO) substrates. The use of Nafion prevented film “peel off,” thus ensuring a good substrate adhesion. Electrochemical impedance spectroscopy reveals that TEG had a catalytic performance comparable to that of Pt, suggesting its use as counter electrode material. As expected, the DSSC fabricated with Nafion solubilized TEG/FTO as counter electrode shows an efficiency of about 2.8%, comparable to Pt counter electrode based DSSC which has an efficiency of about 3.4%.
Laser mass-spectrometry for online diagnosis of reactive plasmas with many species
Authors: Feng Chun-Lei , Gao Liang , Liu Jia-Hong , Zhang Lei , Ding Hongbin
Published: June 2011

The purpose of this study is to design a diagnostic system for reactive plasma environment by combining molecular-beam time-of-flight (TOF) mass spectroscopy with laser spectroscopy technique. The combination of TOF mass spectrometers and pulsed lasers is favorable in the diagnosis of intermediate species distribution since they allow the simultaneous but separate recording of the spectra of different species. In the plasma system, the intermediate species in electronic ground state or low lying excited state is pumped to higher energy level with resonant laser excitation, and then, the ionization with a second laser system is possible which can readily be detected by the TOF analyzer. The ionization itself is only used as a detection mechanism for the observation of the excitation of these states. In this manner, the population distribution of intermediate species can be determined with state-selective and mass-selective feature. Also, in this article, a flexible data acquisition and automatic control system based on LABVIEW was designed to integrate all the stand-alone measurement instruments including a TOF spectrometer, a laser system, a high performance oscilloscope, and a digital delay generator into a single personal computer-based control unit. Moreover, a virtual Boxcar integrator with hundreds of channels has been developed to enhance the signal while filtering out the random noises. Finally, the many potentials of this technique in the application of plasma diagnosis will be discussed.
Femtosecond laser crystallization of amorphous Ge
Authors: Salihoglu Omer , Kürüm Ulas¸ , Gul Yaglioglu H. , Elmali Ayhan , Aydinli Atilla
Published: June 2011

Ultrafast crystallization of amorphous germanium (a-Ge) in ambient has been studied. Plasma enhanced chemical vapor deposition grown a-Ge was irradiated with single femtosecond laser pulses of various durations with a range of fluences from below melting to above ablation threshold. Extensive use of Raman scattering has been employed to determine post solidification features aided by scanning electron microscopy and atomic force microscopy measurements. Linewidth of the Ge optic phonon at 300 cm−1 as a function of laser fluence provides a signature for the crystallization of a-Ge. Various crystallization regimes including nanostructures in the form of nanospheres have been identified.
Shear flow over a porous layer: Velocity in the real proximity of the interface via rheological tests
Authors: Carotenuto Claudia , Minale Mario
Published: June 2011

In this paper, we have experimentally investigated the velocity profile of a fluid undergoing simple shear above a porous medium. To this end, we used for the first time rheological tests performed with a constant stress rheometer equipped with parallel plate geometry with a real porous medium glued on the lower plate. The velocity at the interface between the porous layer and the free fluid was inferred by extrapolating the linear velocity profile in the free fluid to the interface. These data were nicely compared with predictions obtained integrating the Brinkman extension of Darcy law in the porous medium together with Stokes equations in the free fluid coupled at the interface by the continuity of velocity and by the momentum balance suggested by Ochoa-Tapia and Whitaker [Int. J. Heat Mass Transfer 38(14), 2635 (1995)]. In the literature, the physical origin of the stress jump imposed by Ochoa-Tapia and Whitaker at the interface has been attributed to a perturbation of the velocity profile in the vicinity of the interface, both in the porous medium and in the free fluid. For the first time, the disturbance in the free fluid has been measured and quantified resulting in a satisfactory agreement with theoretical predictions.
The onset of double diffusive convection in a binary Maxwell fluid saturated porous layer with cross-diffusion effects
Authors: Malashetty M. S. , Biradar Bharati S.
Published: June 2011

The onset of double diffusive convection in a binary Maxwell fluid saturated porous layer with cross diffusion effects is studied using linear and weakly nonlinear stability analyses. The modified Darcy-Maxwell model is used for the momentum equation. The onset criterion for stationary and oscillatory convection is derived analytically. There is a competition between the processes of viscoelasticity and diffusions that causes the convection to set in through oscillatory rather than stationary. The effect of relaxation parameter, Dufour and Soret parameters, Lewis number, solute Rayleigh number, Vadasz number, and normalized porosity parameter on the stability of the system is investigated. The nonlinear theory based on the truncated representation of Fourier series method is used to find the heat and mass transfer. The effect of various parameters on transient heat and mass transfer is also brought out.
Progressive breakdown dynamics and entropy production in ultrathin SiO2 gate oxides
Authors: Miranda E. , Jiménez D. , Suñé J.
Published: June 2011

The progressive breakdown of ultrathin (≈2nm) SiO2 gate oxides subjected to constant electrical stress is investigated using a simple equivalent circuit model. It is shown how the interplay among series, parallel, and filamentary conductances that represent the breakdown path and its surroundings leads under certain hypothesis to a sigmoidal current-time characteristic compatible with the experimental observations. The dynamical properties of the breakdown trajectories are analyzed in terms of the logistic potential function, the Lyapunov exponent, and the system’s attractor. It is also shown that the current evolution is compatible with Prigogine’s minimum entropy production principle.
Padé spectrum decompositions of quantum distribution functions and optimal hierarchical equations of motion construction for quantum open systems
Authors: Hu Jie , Luo Meng , Jiang Feng , Xu Rui-Xue , Yan YiJing
Published: June 2011

Padé spectrum decomposition is an optimal sum-over-poles expansion scheme of Fermi function and Bose function [J. Hu, R. X. Xu, and Y. J. Yan, J. Chem. Phys. 133, 101106 (2010)]10.1063/1.3484491. In this work, we report two additional members to this family, from which the best among all sum-over-poles methods could be chosen for different cases of application. Methods are developed for determining these three Padé spectrum decomposition expansions at machine precision via simple algorithms. We exemplify the applications of present development with optimal construction of hierarchical equations-of-motion formulations for nonperturbative quantum dissipation and quantum transport dynamics. Numerical demonstrations are given for two systems. One is the transient transport current to an interacting quantum-dots system, together with the involved high-order co-tunneling dynamics. Another is the non-Markovian dynamics of a spin-boson system.
Development of a high pressure automated lag time apparatus for experimental studies and statistical analyses of nucleation and growth of gas hydrates
Authors: Maeda Nobuo , Wells Darrell , Becker Norman C. , Hartley Patrick G. , Wilson Peter W. , Haymet Anthony D. J. , Kozielski Karen A.
Published: June 2011

Nucleation in a supercooled or a supersaturated medium is a stochastic event, and hence statistical analyses are required for the understanding and prediction of such events. The development of reliable statistical methods for quantifying nucleation probability is highly desirable for applications where control of nucleation is required. The nucleation of gas hydrates in supercooled conditions is one such application. We describe the design and development of a high pressure automated lag time apparatus (HP-ALTA) for the statistical study of gas hydrate nucleation and growth at elevated gas pressures. The apparatus allows a small volume (≈150 μl) of water to be cooled at a controlled rate in a pressurized gas atmosphere, and the temperature of gas hydrate nucleation, Tf, to be detected. The instrument then raises the sample temperature under controlled conditions to facilitate dissociation of the gas hydrate before repeating the cooling-nucleation cycle again. This process of forming and dissociating gas hydrates can be automatically repeated for a statistically significant (>100) number of nucleation events. The HP-ALTA can be operated in two modes, one for the detection of hydrate in the bulk of the sample, under a stirring action, and the other for the detection of the formation of hydrate films across the water-gas interface of a quiescent sample. The technique can be applied to the study of several parameters, such as gas pressure, cooling rate and gas composition, on the gas hydrate nucleation probability distribution for supercooled water samples.
Vibrationally quantum-state-specific dynamics of the reactions of CN radicals with organic molecules in solution
Authors: Rose Rebecca A. , Greaves Stuart J. , Oliver Thomas A. A. , Clark Ian P. , Greetham Gregory M. , Parker Anthony W. , Towrie Michael , Orr-Ewing Andrew J.
Published: June 2011

The dynamics of reactions of CN radicals with cyclohexane, d12-cyclohexane, and tetramethylsilane have been studied in solutions of chloroform, dichloromethane, and the deuterated variants of these solvents using ultraviolet photolysis of ICN to initiate a reaction. The H(D)-atom abstraction reactions produce HCN (DCN) that is probed in absorption with sub-picosecond time resolution using ∼500 cm−1 bandwidth infrared (IR) pulses in the spectral regions corresponding to C−H (or C−D) and C≡N stretching mode fundamental and hot bands. Equivalent IR spectra were obtained for the reactions of CN radicals with the pure solvents. In all cases, the reaction products are formed at early times with a strong propensity for vibrational excitation of the C−H (or C−D) stretching (v3) and H−C−N (D−C−N) bending (v2) modes, and for DCN products there is also evidence of vibrational excitation of the v1 mode, which involves stretching of the C≡N bond. The vibrationally excited products relax to the ground vibrational level of HCN (DCN) with time constants of ∼130–270 ps (depending on molecule and solvent), and the majority of the HCN (DCN) in this ground level is formed by vibrational relaxation, instead of directly from the chemical reaction. The time-dependence of reactive production of HCN (DCN) and vibrational relaxation is analysed using a vibrationally quantum-state specific kinetic model. The experimental outcomes are indicative of dynamics of exothermic reactions over an energy surface with an early transition state. Although the presence of the chlorinated solvent may reduce the extent of vibrational excitation of the nascent products, the early-time chemical reaction dynamics in these liquid solvents are deduced to be very similar to those for isolated collisions in the gas phase. The transient IR spectra show additional spectroscopic absorption features centered at 2037 cm−1 and 2065 cm−1 (in CHCl3) that are assigned, respectively, to CN-solvent complexes and recombination of I atoms with CN radicals to form INC molecules. These products build up rapidly, with respective time constants of 8−26 and 11–22 ps. A further, slower rise in the INC absorption signal (with time constant >500 ps) is attributed to diffusive recombination after escape from the initial solvent cage and accounts for more than 2/3 of the observed INC.
Conduction mechanism in Polyaniline-flyash composite material for shielding against electromagnetic radiation in X-band & Ku band
Authors: Singh Avanish Pratap , S. Anoop Kumar , Chandra Amita , Dhawan S. K.
Published: June 2011

β–Naphthalene sulphonic acid (β–NSA) doped polyaniline (PANI)–flyash (FA) composites have been prepared by chemical oxidative polymerization route whose conductivity lies in the range 2.37–21.49 S/cm. The temperature dependence of electrical conductivity has also been recorded which shows that composites follow Mott's 3D–VRH model. SEM images demonstrate that β–NSA leads to the formation of the tubular structure with incorporated flyash phase. TGA studies show the improvement in thermal stability of composites with increase in loading level of flyash. Complex parameters i.e. permittivity (ɛ* = ɛ′- iɛ″) and permeability (μ*=μ′- iμ″) of PANI-FA composites have been calculated from experimental scattering parameters (S11 & S21) using theoretical calculations given in Nicholson–Ross and Weir algorithms. The microwave absorption properties of the composites have been studied in X-band (8.2 – 12.4 GHz) & Ku–Band (12.4 – 18 GHz) frequency range. The maximum shielding effectiveness observed was 32dB, which strongly depends on dielectric loss and volume fraction of flyash in PANI matrix.
Long-term membership of whale sharks (Rhincodon typus) in coastal aggregations in Seychelles and Djibouti
Authors: Rowat David , Brooks Katie , March Abi , McCarten Ciara , Jouannet Daniel , Riley Luke , Jeffreys Gareth , Perri Morgan , Vely Michel , Pardigon Bruno
Published: June 2011

In coastal waters of several locations globally, whale sharks (Rhincodon typus) form seasonal aggregations, most of which largely comprise juvenile males of 4–8 m length. Evaluation of the period that individuals stay within these size- and age-specific groupings will clarify our understanding of the transition between life-stages in this species and how this might affect their long-term conservation. Long-term photo-identification studies in Seychelles and Djibouti provided data to evaluate this. The Seychelles aggregation had 443 individuals averaging 5.8 m identified between 2001 and 2009; however, the Djibouti aggregation comprised smaller individuals of 3.7 m mean length with 297 individuals identified between 2003 and 2010. In Seychelles, 27% of individuals identified in 2001 were seen again in 2009, while in Djibouti none of the whale sharks identified in 2003 were seen in 2010, although 13% from 2004 were. This suggests that membership periods in the Djibouti aggregation are shorter than in the other juvenile aggregations, such as in Seychelles. Continued photo-identification monitoring of other Indian Ocean aggregations might in time show the next location of these young sharks’ life-cycle and thereby allow development of informed national and regional management plans.
Uterine fluid composition of the dwarf ornate wobbegong shark (Orectolobus ornatus) during gestation
Authors: Ellis Megan T. , Otway Nicholas M.
Published: June 2011

Low fecundity in chondrichthyans makes them extremely susceptible to fishing, so understanding the various reproductive strategies in this group is vital for management. Knowledge of the uterine fluid (UF) composition throughout gestation is fundamental to this understanding, yet is restricted to a few species. This study focussed on the UF composition of the wobbegong (Orectolobus ornatus), which inhabits coastal waters off eastern Australia. The UF was quantified throughout pregnancy. Fluids surrounding uterine eggs had a complex composition, with mean urea (98.48 mmol L–1), sodium (560.25 mmol L–1) and potassium (13.93 mmol L–1) concentrations significantly greater than those in seawater. A change in composition, from complex to simple, occurred after 3–4 months gestation. Major electrolyte concentrations then resembled seawater for the remainder of gestation, suggesting the flushing of the uteri with seawater and evidenced by fluctuating low levels of urea. The gestation period reflected the time for metabolism of yolk stores, osmotic and ionic adjustment, development of functioning immunological systems and prevention of external yolk sac damage. Our study is the first documentation of UF composition for a wobbegong shark and increases understanding of its reproductive biology.
From hunters to nature observers: a record of 53 years of diver attitudes towards sharks and rays and marine protected areas
Authors: Whatmough Sally , Van Putten Ingrid , Chin Andrew
Published: June 2011

Human values, perceptions, attitudes and interactions with the natural environment have been found to change over time, with social and economic information used to inform management decisions and actions. Content analysis is applied here to a 53-year long collection of the popular dive magazine, SportDiving, to identify recreational divers’ experiences with regard to sharks and rays, the Great Barrier Reef (GBR) and marine protected areas (MPAs). This analysis suggests there has been a diversification of diver activities with the emergence of passive-observational activities such as SCUBA diving. Attitudes towards sharks and rays have changed significantly, with recreational divers changing from a group that could be described as adventure-seeking hunters to a group that can be described as nature-appreciating observers, suggesting an increase in conservation awareness. The GBR continues to be a highly regarded dive destination, with divers perceiving positive effects of protection within MPAs. However, declines in the abundance of large fish and sharks and rays were occasionally reported throughout the 53 year period. Collectively, these types of data can show changes in resource-use patterns, perceptions and attitudes and provide information that supplements scientific monitoring data. These data may be valuable where scientific data is scarce, historical records difficult to obtain, and where attitudinal change can significantly affect future resource use.
Distribution, reproduction and population structure of three gulper sharks (Centrophorus, Centrophoridae) in south-east Australian waters
Authors: Graham K. J. , Daley R. K.
Published: June 2011

Gulper sharks (Centrophorus spp.) are commercially fished in all oceans but the taxonomy and biology of many species are not clearly defined, and stocks are extremely vulnerable to over-exploitation. We present distributional, size-frequency and reproductive data for three species (Centrophorus harrissoni, C. moluccensis and C. zeehaani) that fishing has largely extirpated from the south-east Australian upper continental slope. Trawl-survey catches in 1976–77 from lightly exploited stocks comprised mostly mature males with few mature females or juveniles; a 2009 long-line survey caught higher proportions of mature females and, for C. harrissoni, more juveniles. Females of the three species grew larger and reached maturity at a greater size than males and, for both sexes, maturity sizes were more than 80% of their maximum observed lengths. Reproduction was continuous but data were insufficient to determine seasonality. Ovarian and uterine fecundity were singular for C. zeehaani whereas C. harrissoni and C. moluccensis developed two oocytes and produced one or two embryos; evidence suggests that the left-side uterus is less functional than the right-side. In response to these species’ inherent low productivity and continuing reduced numbers, managers have introduced landing restrictions and area closures to enhance Centrophorus stocks in southern Australian waters.
Abundance, habitat use and movement patterns of the shovelnose guitarfish (Rhinobatos productus) in a restored southern California estuary
Authors: Farrugia Thomas J. , Espinoza Mario , Lowe Christopher G.
Published: June 2011

Coastal elasmobranchs such as the shovelnose guitarfish (Rhinobatos productus) seasonally use bays and estuaries for mating, pupping and feeding. However, many human-populated coastal areas have been developed, making them unavailable to coastal fish populations. The Full Tidal Basin (FTB) of the Bolsa Chica Ecological Reserve, California, USA, was completed in 2006, with the aim to restore lost estuarine habitat in southern California. Monthly abundance surveys conducted inside the FTB between June 2008 and September 2009 showed that shovelnose guitarfish were present throughout the year. Over 96% of the individuals caught were juveniles and these were most abundant in waters between 20°C and 24°C. Concurrently, 23 shovelnose guitarfish were fitted with coded acoustic transmitters and continuously tracked within the FTB for 16 months. Telemetry data showed individuals remained inside the FTB for, on average, 73.9 days (range 15–172 days), and made few movements between the FTB and the ocean. Tagged individuals disproportionately used mud habitats and waters at temperatures of 22°C, both of which are more common in the FTB than the neighbouring coastal ocean. The present study examined the structure and functionality of a restored estuary and suggests that the FTB is important habitat for a benthic predator, a promising result three years after restoration.
Reducing the environmental impact of shark-control programs: a case study from KwaZulu-Natal, South Africa
Authors: Cliff Geremy , Dudley Sheldon F. J.
Published: June 2011

Large-scale shark-control programs at popular beaches in New South Wales and Queensland, Australia, and KwaZulu-Natal (KZN), South Africa, provide protection against shark attack. Although these programs have enhanced bathing safety, reducing the environmental impacts of decades of fishing for large sharks and the associated by-catch remains a challenge. Over the past three decades, there have been several interventions to reduce such impact in the KZN program. The first was the release of all live sharks, including those species known to be responsible for fatal shark attacks. Measures to reduce catches of sharks associated with the winter influx of shoals of sardines, Sardinops sagax, have been increasingly successful. In addition, extensive removal of nets has resulted in a major reduction in effort. Collectively, these initiatives reduced mortalities of sharks by 64%. Baited lines, termed drumlines, were introduced at 18 beaches, where they replaced some of the nets. The former had a far lower by-catch of rays, turtles and cetaceans and significantly lower catches of certain shark species. Replacement of some nets with drumlines is planned for the remaining beaches. Only two attacks, both non-fatal, have occurred at protected beaches in KZN over the past three decades, indicating that the program has maintained its public safety mandate while it has succeeded in reducing its impact on the environment.
Mechanism of von Willebrand factor scissile bond cleavage by a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13)
Authors: Xiang Yaozu , de Groot Rens , Crawley James T. B. , Lane David A.
Published: June 2011

The platelet-tethering function of von Willebrand factor (VWF) is proteolytically regulated by ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), which cleaves the Tyr1605-Met1606 (P1-P1′) bond in the VWF A2 domain. To date, most of the functional interactions between ADAMTS13 and VWF that have been characterized involve VWF residues that are C terminal to the scissile bond. We now demonstrate that the substrate P3 position in VWF, Leu1603, is a critical determinant of VWF proteolysis. When VWF Leu1603 was substituted with Ser, Ala, Asn, or Lys in a short VWF substrate, VWF115, proteolysis was either greatly reduced or ablated (up to 400-fold reduction in kcat/Km). As Leu1603 must interact with residues proximate to the Zn2+ion coordinated in the active center of ADAMTS13, we sought the corresponding S3 interacting residues. Substitution of 10 candidate residues in the metalloprotease domain of ADAMTS13 identified two spatially separated clusters centered on Leu198 or Val195 (acting with Leu232 and Leu274, or with Leu151, respectively), as possible subsites interacting with VWF. These experimental findings using the short VWF115 substrate were replicated using full-length VWF. It is hypothesized that VWF Leu1603 interacts with ADAMTS13 Leu198/Leu232/Leu274 and that Val195/Leu151 may form part of a S1 subsite. The recognition of VWF Leu1603 by ADAMTS13, in conjunction with previously reported remote exosites C terminal of the cleavage site, suggests a mechanism whereby the VWF P1-P1′ scissile bond is brought into position over the active site for cleavage. Together with recently characterized remote exosite interactions, these findings provide a general framework for understanding the ADAMTS family substrate interactions.
Direct visualization of myosin-binding protein C bridging myosin and actin filaments in intact muscle
Authors: Luther Pradeep K. , Winkler Hanspeter , Taylor Kenneth , Zoghbi Maria E. , Craig Roger , Padrón Raúl , Squire John M. , Liu Jun
Published: June 2011

Myosin-binding protein C (MyBP-C) is a thick filament protein playing an essential role in muscle contraction, and MyBP-C mutations cause heart and skeletal muscle disease in millions worldwide. Despite its discovery 40 y ago, the mechanism of MyBP-C function remains unknown. In vitro studies suggest that MyBP-C could regulate contraction in a unique way—by bridging thick and thin filaments—but there has been no evidence for this in vivo. Here we use electron tomography of exceptionally well preserved muscle to demonstrate that MyBP-C does indeed bind to actin in intact muscle. This binding implies a physical mechanism for communicating the relative sliding between thick and thin filaments that does not involve myosin and which could modulate the contractile process.
Origin of hysteresis in the transfer characteristic of carbon nanotube field effect transistor
Authors: Ong H G , Cheah J W , Zou X , Li B , Cao X H , Tantang H , Li L-J , Zhang H , Han G C , Wang J
Published: June 2011

Using electrostatic force microscopy, we show direct evidence of charge injection at the carbon nanotube–SiO2 interface leading to the appearance of hysteresis. The dynamic screening effect of the injected charges is revealed step by step. Further temperature dependent tests also demonstrate the effect of SiO2 surface chemistry. Furthermore, we conclude that it is not practical to use such a device for memory application because of data retention and storage density issues.
Assessing the Diagnostic Accuracy of Pulse Pressure Variations for the Prediction of Fluid Responsiveness
Authors: Cannesson Maxime , Le Manach Yannick , Hofer Christoph K. , Goarin Jean Pierre , Lehot Jean-Jacques , Vallet Benoît , Tavernier Benoît
Published: June 2011

Background

Respiratory arterial pulse pressure variations (PPV) are the best predictors of fluid responsiveness in mechanically ventilated patients during general anesthesia. However, previous studies were performed in a small number of patients and determined a single cutoff point to make clinical discrimination. The authors sought to test the predictive value of PPV in a large, multicenter study and to express it using a gray zone approach.

Methods

The authors studied 413 patients during general anesthesia and mechanical ventilation in four centers. PPV, central venous pressure, and cardiac output were recorded before and after volume expansion (VE). Response to VE was defined as more than 15% increase in cardiac output after VE. The following approaches were used to determine the gray zones: resampled and two-graph receiver operator characteristic curves. The impact of changes in the benefit-risk balance of VE on the gray zone was also evaluated.

Results

The authors observed 209 responders (51%) and 204 nonresponders (49%) to VE. The area under receiver operating characteristic curve was 0.89 (95% CI: 0.86-0.92) for PPV, compared with 0.57 (95% CI: 0.54-0.59) for central venous pressure (P < 10). The gray zone approach identified a range of PPV values (between 9% and 13%) for which fluid responsiveness could not be predicted reliably. These PPV values were seen in 98 (24%) patients. Changes in the cost ratio of VE moderately affected the gray zone limits.

Conclusion

Despite a strong predictive value, PPV may be inconclusive (between 9% and 13%) in approximately 25% of patients during general anesthesia.