17,269 research outputs found
Benchmark calculations for reduced density-matrix functional theory
Reduced density-matrix functional theory (RDMFT) is a promising alternative
approach to the problem of electron correlation. Like standard density
functional theory, it contains an unknown exchange-correlation functional, for
which several approximations have been proposed in the last years. In this
article, we benchmark some of these functionals in an extended set of molecules
with respect to total and atomization energies. Our results show that the most
recent RDMFT functionals give very satisfactory results compared to more
involved quantum chemistry and density functional approaches.Comment: 17 pages, 1 figur
Onset of Electron Acceleration in a Flare Loop
We carried out detailed analysis of X-ray and radio observations of a simple
flare loop that occurred on 12th August 2002, with the impulsive hard X-ray
(HXR) light curves dominated by a single pulse. The emission spectra of the
early impulsive phase are consistent with an isothermal model in the coronal
loop with a temperature reaching several keVs. A power-law high-energy spectral
tail is evident near the HXR peak time, in accordance with the appearance of
footpoints at high energies, and is well correlated with the radio emission.
The energy content of the thermal component keeps increasing gradually after
the disappearance of this nonthermal component. These results suggest that
electron acceleration only covers a central period of a longer and more gradual
energy dissipation process and that the electron transport within the loop
plays a crucial role in the formation of the inferred power-law electron
distribution. The spectral index of power-law photons shows a very gradual
evolution indicating a quasi-steady state of the electron accelerator, which is
confirmed by radio observations. These results are consistent with the theory
of stochastic electron acceleration from a thermal background. Advanced
modeling with coupled electron acceleration and spatial transport processes is
needed to explain these observations more quantitatively, which may reveal the
dependence of the electron acceleration on the spatial structure of the
acceleration region
Use of inorganic fertiliser in place of poultry manure for rehabilitation of gold and bauxite ore refining residues
Ore refining residues are difficult substrates for revegetation because they often contain extremely low plant available levels of one or more essential elements (Hossner and Hons 1992). Organic amendments would generally be attractive additions for revegetation because residues also contain little organic matter, and organic amendments may also ameliorate elevated concentrations of salts and other elements. However organic materials are generally not available on mine sites in sufficient quantities and they are bulky handle. In the present study, the opportunities for substituting inorganic fertilisers in place of poultry manure were investigated for revegetation of three alkaline, variably saline residues: bauxite residue (mixed sand and clay fractions), bauxite residue sand, and gold refining residue from mined oxide clays
Words That Can Kill: The Mugesera Speech and the 1994 Tutsi Genocide in Rwanda
One of the most significant extant documents attesting to the dissemination of genocide ideology in Rwanda in the early 1990s is the speech delivered on 22 November 1992 by the political figure Léon Mugesera, a member of the incumbent MRND party. It is particularly significant because it constitutes the earliest example of explicit genocidal discourse expressed by a member of the ruling political party in a public forum, and as such it has often been regarded as offering a ‘blueprint’ for the practical implementation of the genocide. In addition, the contents of the speech have been the subject of intense scrutiny and heated debate within the framework of a judicial process in Canada spanning more than a decade to determine whether Mugesera should be deported to Rwanda to face prosecution for genocide. The original speech was delivered in Kinyarwanda, the national language of Rwanda, which effectively meant it was largely inaccessible to foreign commentators until it was translated into French and English. This article examines key thematic, lexical and stylistic elements within the original speech as it was heard by its target audience, as well as fundamental issues raised by the Canadian hearings relating to the translation process such as accuracy, fidelity, impartiality and subjectivity which were crucial elements in the decision-making process which finally led to Mugesera being deported to Rwanda on 23 January 2012
"A Genocide of Little Importance": The Impact of the Terminology Used by Members of the French Government on the Representation of the 1994 Tutsi Genocide in Rwanda'
In May 1994 France distinguished itself from other more reticent members of the international community by being the first country to explicitly identify the events occurring in Rwanda as a ‘genocide’. The present article elucidates the impact of the very particular ways in which key French government figures used the term ‘genocide’ to describe the Tutsi genocide in Rwanda both during and after the events of 1994
Unbuttoned: : The interaction between provocativeness of female work attire and occupational status
This document is the Accepted Manuscript. The final publication is available at Springer via https://doi.org/10.1007/s11199-015-0450-8.Gender-biased standards in United Kingdom (UK) workplaces continue to exist. Women experience gender discrimination in judgements of competence, even by other women. Clothing cues can subtly influence professional perceptions of women. The aim of this study was to investigate how minor manipulations to female office clothing affect the judgements of competence of them by other UK females and to examine whether such effects differ with occupational status. One group of female university students (n = 54) and one group of employed females (n = 90), all from London and the East of England, rated images of faceless female targets, on a global competence measure derived from six competence ratings (of intelligence, confidence, trustworthiness, responsibility, authority, and organisation). The dress style was conservative but varied slightly by skirt length and the number of buttons unfastened on a blouse. The female targets were ascribed different occupational roles, varying by status (high – senior manager, or low - receptionist). Participants viewed the images for a maximum of 5 s before rating them. Overall participants rated the senior manager less favourably when her clothing was more provocative, but more favourably when dressed more conservatively (longer skirt, buttoned up blouse). This interaction between clothing and status was not present for the receptionist. Employed participants also rated females lower than did student participants. We conclude that even subtle changes to clothing style can contribute towards negative impressions of the competence of women who hold higher status positions in a UK cultural contextPeer reviewedFinal Accepted Versio
Electron Inertial Effects on Rapid Energy Redistribution at Magnetic X-points
The evolution of non-potential perturbations to a current-free magnetic
X-point configuration is studied, taking into account electron inertial effects
as well as resistivity. Electron inertia is shown to have a negligible effect
on the evolution of the system whenever the collisionless skin depth is less
than the resistive scale length. Non-potential magnetic field energy in this
resistive MHD limit initially reaches equipartition with flow energy, in
accordance with ideal MHD, and is then dissipated extremely rapidly, on an
Alfvenic timescale that is essentially independent of Lundquist number. In
agreement with resistive MHD results obtained by previous authors, the magnetic
field energy and kinetic energy are then observed to decay on a longer
timescale and exhibit oscillatory behavior, reflecting the existence of
discrete normal modes with finite real frequency. When the collisionless skin
depth exceeds the resistive scale length, the system again evolves initially
according to ideal MHD. At the end of this ideal phase, the field energy decays
typically on an Alfvenic timescale, while the kinetic energy (which is equally
partitioned between ions and electrons in this case) is dissipated on the
electron collision timescale. The oscillatory decay in the energy observed in
the resistive case is absent, but short wavelength structures appear in the
field and velocity profiles, suggesting the possibility of particle
acceleration in oppositely-directed current channels. The model provides a
possible framework for interpreting observations of energy release and particle
acceleration on timescales down to less than a second in the impulsive phase of
solar flares.Comment: 30 pages, 8 figure
RC J1148+0455 identification: gravitational lens or group of galaxies ?
The structure of the radio source RC B1146+052 of the ``Cold'' catalogue is
investigated by data of the MIT-GB-VLA survey at 4850 MHz. This source belongs
to the steep spectrum radio sources subsample of the RC catalogue. Its spectral
index is = -1.04. The optical image of this source obtained with 6m
telescope is analysed. The radio source center is situated in a group of 8
galaxies of about 24 in the R-filter. The possible explanations of the
complex structure of radio components are considered.Comment: 6 pages, 5 figures, uses psfig.sty. This was the poster as presented
on Gamow Memorial Internat. Conference GMIC'99 "Early Universe: Cosmological
Problems and Instrumental Technologies" in St.Petersburg, 23-27 Aug., 1999.
Submitted to Proceedings to be published in A&A Transaction
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