1,138 research outputs found

    Importance-satisfaction analysis for marine-park hinterlands: A Western Australian case study

    Get PDF
    Tourist use of national and marine parks continues to increase worldwide. Effective management depends on being able to evaluate the quality of visitors' experiences, as well as protecting the natural environment. In tourism management, importance-performance analysis (IPA) has been used as part of quality management. It has recently been applied to national park management. This paper reconceptualises this analysis to one of importance satisfaction, enabling a focus on the quality of experience. Two methods, importanceperformance analysis and service quality gap, were modified and applied in the hinterland of Swan Estuary Marine Park in Western Australia. Both provided data useful for evaluating satisfaction, with the choice of method depending on the end user's resources and requirements as well as cognisance of each method's limitations. For most of the Marine Park attributes, satisfaction exceeded importance and hence no management attention is needed. Exceptions were the condition of the Swan River and associated footpaths, and the presence of litter and wildlife. For these, satisfaction was lower than importance, suggesting management attention is needed

    Phonon transport in large scale carbon-based disordered materials: Implementation of an efficient order-N and real-space Kubo methodology

    Get PDF
    We have developed an efficient order-N real-space Kubo approach for the calculation of the phonon conductivity which outperforms state-of-the-art alternative implementations based on the Green's function formalism. The method treats efficiently the time-dependent propagation of phonon wave packets in real space, and this dynamics is related to the calculation of the thermal conductance. Without loss of generality, we validate the accuracy of the method by comparing the calculated phonon mean free paths in disordered carbon nanotubes (isotope impurities) with other approaches, and further illustrate its upscalability by exploring the thermal conductance features in large width edge-disordered graphene nanoribbons (up to ~20 nm), which is out of the reach of more conventional techniques. We show that edge-disorder is the most important scattering mechanism for phonons in graphene nanoribbons with realistic sizes and thermal conductance can be reduced by a factor of ~10.Comment: Accepted for publication in Physical Review B - Rapid Communication

    Three-dimensional simulations of laser-plasma interactions at ultrahigh intensities

    Get PDF
    Three-dimensional (3D) particle-in-cell (PIC) simulations are used to investigate the interaction of ultrahigh intensity lasers (>1020> 10^{20} W/cm−2^{-2}) with matter at overcritical densities. Intense laser pulses are shown to penetrate up to relativistic critical density levels and to be strongly self-focused during this process. The heat flux of the accelerated electrons is observed to have an annular structure when the laser is tightly focused, showing that a large fraction of fast electrons is accelerated at an angle. These results shed light into the multi-dimensional effects present in laser-plasma interactions of relevance to fast ignition of fusion targets and laser-driven ion acceleration in plasmas.Comment: 2 pages, 1 figur

    An alternate proton acceptor for excited-state proton transfer in green fluorescent protein: Rewiring GFP

    Get PDF
    The neutral form of the chromophore in wild-type green fluorescent protein (wtGFP) undergoes excited-state proton transfer (ESPT) upon excitation, resulting in characteristic green (508 nm) fluorescence. This ESPT reaction involves a proton relay from the phenol hydroxyl of the chromophore to the ionized side chain of E222, and results in formation of the anionic chromophore in a protein environment optimized for the neutral species (the I* state). Reorientation or replacement of E222, as occurs in the S65T and E222Q GFP mutants, disables the ESPT reaction and results in loss of green emission following excitation of the neutral chromophore. Previously, it has been shown that the introduction of a second mutation (H148D) into S65T GFP allows the recovery of green emission, implying that ESPT is again possible. A similar recovery of green fluorescence is also observed for the E222Q/H148D mutant, suggesting that D148 is the proton acceptor for the ESPT reaction in both double mutants. The mechanism of fluorescence emission following excitation of the neutral chromophore in S65T/H148D and E222Q/H148D has been explored through the use of steady state and ultrafast time-resolved fluorescence and vibrational spectroscopy. The data are contrasted with those of the single mutant S65T GFP. Time-resolved fluorescence studies indicate very rapid (<1 ps) formation of I* in the double mutants, followed by vibrational cooling on the picosecond time scale. The time-resolved IR difference spectra are markedly different to those of wtGFP or its anionic mutants. In particular, no spectral signatures are apparent in the picosecond IR difference spectra that would correspond to alteration in the ionization state of D148, leading to the proposal that a low-barrier hydrogen bond (LBHB) is present between the phenol hydroxyl of the chromophore and the side chain of D148, with different potential energy surfaces for the ground and excited states. This model is consistent with recent high-resolution structural data in which the distance between the donor and acceptor oxygen atoms is =2.4 Ã…. Importantly, these studies indicate that the hydrogen-bond network in wtGFP can be replaced by a single residue, an observation which, when fully explored, will add to our understanding of the various requirements for proton-transfer reactions within proteins

    Labour and Northern Ireland: The Long Road Back to Devolution

    Get PDF

    Irish Pan nationalism: Myth or Reality?

    Get PDF

    Molecular structure of S-ethylthioacrylate Combined vibrational spectroscopic and abinitioSCF-MO study

    Get PDF
    Ab initio 6-31G* SCF-MO calculations have been carried out on S-ethyl thioacrylate [CH2CHC(O)SCH2CH3]. Fully optimized geometries, relative stabilities, dipole moments and harmonic force fields for several conformers of this molecule have been determined and the results compared with those for similar molecules. Together with FTIR and Raman spectroscopic data, the theoretical results demonstrate that S-ethyl thioacrylate exists in two different conformations about the Cα–C bond (the s-cis and s-trans forms, with CC–CO dihedral angles equal to 0° and 180°, respectively); the s-cis conformation being more stable than the s-trans form by ca. 6 kJ mol-1 for the isolated molecule. Comparison of the experimental and theoretical vibrational spectra confirms that, as concluded from our previous study on the analogous trans-S-ethyl thiocrotonate molecule (R. Fausto, P. J. Tonge and P. R. Carey, J. Chem. Soc., FaradayTrans., 1994, 90, 3491), the presence of the s-trans isomer of an α,β-unsaturated thioester can be successfully monitored by the IR band at ca. 1170 cm-1, ascribed to the Cα–C stretching mode of this form. In addition, we were also able to identify some IR bands sensitive to the conformation of the ethyl group that may be used as spectroscopic probes to study conformational equilibria associated with this internal degree of freedom in more complex S-ethyl thioester
    • …
    corecore