5,086 research outputs found

    Mechanisms of Auger-induced chemistry derived from wave packet dynamics

    Get PDF
    To understand how core ionization and subsequent Auger decay lead to bond breaking in large systems, we simulate the wave packet dynamics of electrons in the hydrogenated diamond nanoparticle C_(197)H_(112). We find that surface core ionizations cause emission of carbon fragments and protons through a direct Auger mechanism, whereas deeper core ionizations cause hydrides to be emitted from the surface via remote heating, consistent with results from photon-stimulated desorption experiments [Hoffman A, Laikhtman A, (2006) J Phys Condens Mater 18:S1517–S1546]. This demonstrates that it is feasible to study the chemistry of highly excited large-scale systems using simulation and analysis tools comparable in simplicity to those used for classical molecular dynamics

    Time for "justice" : Research to inform the development of a human rights framework for the design and implementation of an "acknowledgement and accountability forum" on historic abuse of children in Scotland

    Get PDF
    In 2002, Chris Daly raised a petition to the Scottish Executive (PE535) calling for an independent inquiry into the historic abuse of children in Scotland. This led to the setting up of a reference group in 2003, in order to explore the role of a truth and reconciliation process that was identified as an important step in dealing with historic abuse. In 2004, there was an apology for such abuse by the then First Minister, Jack McConnell. In 2005, Tom Shaw led the Historic Abuse Systemic Review. This covered the period 1950 – 1995 and was completed in 2007. In 2006, a sub-group of the reference group that was set up in 2003 identified the need for a service for survivors. This led to the funding of ‘In Care Survivor Scotland’ in 2008, under the umbrella of ‘Open Secret’. It is important to see this current report in this context. Eight years on from the initial petition, it is clear that this process has been seen by many as a long road to acknowledging the need to address outstanding human rights issues in relation to the historic abuse of children in care in Scotland

    U.S. Consumers’ Preference and Willingness to Pay for Country-of-Origin-Labeled Beef Steak and Food Safety Enhancements

    Get PDF
    The mandatory Country of Origin Labeling (COOL) troubles beef exporters to the U.S. This study evaluates the extent that U.S. consumers are receptive to imported steak and their perception of food safety level of beef from various countries. In addition, using conjoint analysis, willingness to pay for strip loin steak from Australia, Canada and the United States is estimated along with several increasingly important food safeties and quality attributes in beef. We find that on average U.S. consumers are willing to pay significantly less for imported steaks.beef, consumer preferences, country-of-origin labeling, conjoint experiment, willingness to pay, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, International Relations/Trade, Livestock Production/Industries,

    Willingness to Pay for Imported Beef and Risk Perception: An application of Individual-Level Parameter

    Get PDF
    The controversy surrounding the Mandatory Country-of-Origin Labeling (COOL) has attracted research attentions. A number of studies have reported consumers are willing to pay more for beef labeled with U.S. origin versus beef from unknown or other origins. Despite that, relatively little is known about what motivates consumers’ preference for origin-labeled food products (Lusk et al 2006). Using Individual-Level Parameters following a mixed logit model, we found that U.S. consumers were willing to pay significantly less for imported steak from Australia and Canada compare to U.S. steak. Further, we found that the negative willingness to pay is associated strongly with consumers’ perception of food safety on the exporting country.beef, country of origin, mixed logit, individual-level parameters, stated choice experiment, Agribusiness, Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety, Marketing, Q13, Q18,

    Protection of the LHC against Unsynchronised Beam Aborts

    Get PDF
    An unsynchronised beam abort in the LHC could damage downstream accelerator components, in particular the extraction septum magnets, the experimental low-beta triplet magnet apertures and the tertiary collimators. Although the LHC beam dumping system includes design features to minimise their frequency, such unsynchronised aborts cannot be excluded. A system of protection devices comprising fixed and moveable diluters and collimators will protect the downstream LHC aperture from the misdirected bunches in case of such a failure. The sources of unsynchronised aborts are described, together with the requirements and design of the protection devices and their expected performance. The accompanying operational requirements and envisaged solutions are discussed, in particular the problem of ensuring the local orbit at the protection devices

    Strongly correlated wave functions for artificial atoms and molecules

    Full text link
    A method for constructing semianalytical strongly correlated wave functions for single and molecular quantum dots is presented. It employs a two-step approach of symmetry breaking at the Hartree-Fock level and of subsequent restoration of total spin and angular momentum symmetries via Projection Techniques. Illustrative applications are presented for the case of a two-electron helium-like single quantum dot and a hydrogen-like quantum dot molecule.Comment: 9 pages. Revtex with 2 GIF and 1 EPS figures. Published version with extensive clarifications. A version of the manuscript with high quality figures incorporated in the text is available at http://calcite.physics.gatech.edu/~costas/qdhelproj.html For related papers, see http://www.prism.gatech.edu/~ph274c

    Conformations of N-Heterocyclic Carbene Ligands in Ruthenium Complexes Relevant to Olefin Metathesis

    Get PDF
    The structure of ruthenium-based olefin metathesis catalyst 3 and model π-complex 5 in solution and in the solid state are reported. The N-tolyl ligands, due to their lower symmetry than the traditional N-mesityl substituents, complicate this analysis, but ultimately provide explanation for the enhanced reactivity of 3 relative to standard catalyst 2. The tilt of the N-tolyl ring provides additional space near the ruthenium center, which is consistent with the enhanced reactivity of 3 toward sterically demanding substrates. Due to this tilt, the more sterically accessible face bears the two methyl substituents of the N-aryl rings. These experimental studies are supported by computational studies of these complexes by DFT. The experimental data provides a means to validate the accuracy of the B3LYP and M06 functionals. B3LYP provides geometries that match X-ray crystal structural data more closely, though it leads to slightly less (0.5 kcal mol^(−1)) accuracy than M06 most likely because it underestimates attractive noncovalent interactions

    Uniqueness of Flat Spherically Symmetric Spacelike Hypersurfaces Admitted by Spherically Symmetric Static Spactimes

    Full text link
    It is known that spherically symmetric static spacetimes admit a foliation by {\deg}at hypersurfaces. Such foliations have explicitly been constructed for some spacetimes, using different approaches, but none of them have proved or even discussed the uniqueness of these foliations. The issue of uniqueness becomes more important due to suitability of {\deg}at foliations for studying black hole physics. Here {\deg}at spherically symmetric spacelike hy- persurfaces are obtained by a direct method. It is found that spherically symmetric static spacetimes admit {\deg}at spherically symmetric hypersurfaces, and that these hypersurfaces are unique up to translation under the time- like Killing vector. This result guarantees the uniqueness of {\deg}at spherically symmetric foliations for such spacetimes.Comment: 10 page
    • …
    corecore