5,839 research outputs found
Accuracy of the Hartree-Fock method for Wigner molecules at high magnetic fields
Few-electron systems confined in two-dimensional parabolic quantum dots at
high magnetic fields are studied by the Hartree-Fock (HF) and exact
diagonalization methods. A generalized multicenter Gaussian basis is proposed
in the HF method. A comparison of the HF and exact results allows us to discuss
the relevance of the symmetry of the charge density distribution for the
accuracy of the HF method. It is shown that the energy estimates obtained with
the broken-symmetry HF wave functions become exact in the infinite
magnetic-field limit. In this limit the charge density of the broken-symmetry
solution can be identified with the classical charge distribution.Comment: to appear in EPJ
Microborings in mid Cretaceous fish teeth
Fish teeth and other remains from the British Cretaceous contain abundant evidence for post-mortem colonization by endolithic organisms. The borings are here recognised as occurring in three morphotypes, including a flask-shaped form not previously recorded. There is strong evidence to suggest that each of these boring types shows a strong preference for a particular substrate histology. The damage and destruction of vertebrate remains by microborings is here considered to exert a major taphonomic control on microvertebrate assemblages. The relationships between the intensity of colonization of vertebrate material by endolithic organisms and palaeoenvironment have implications for using these bone microborings as palaeoenvironmental indicators
Insights from SONATA: Implementing and integrating a microservice-based NFV service platform with a DevOps methodology
A fundamental test of the Higgs Yukawa coupling at RHIC in A+A collisions
Searches for the intermediate boson, , the heavy quantum of the Weak
Interaction, via its semi-leptonic decay, , in the 1970's instead
discovered unexpectedly large hadron production at high , notably ,
which provided a huge background of from internal and external
conversions. Methods developed at the CERN ISR which led to the discovery of
direct-single- in 1974, later determined to be from the semi-leptonic
decay of charm which had not yet been discovered, were used by PHENIX at RHIC
to make precision measurements of heavy quark production in p-p and Au+Au
collisions, leading to the puzzle of apparent equal suppression of light and
heavy quarks in the QGP. If the Higgs mechanism gives mass to gauge bosons but
not to fermions, then a proposal that all 6 quarks are nearly massless in a
QGP, which would resolve the puzzle, can not be excluded. This proposal can be
tested with future measurements of heavy quark correlations in A+A collisionsComment: 12 pages, 16 figures, 26th Winter Workshop on Nuclear Dynamics, Ocho
Rios, Jamaica WI, January 2-9, 2010. Corrected citation of 1974 direct single
lepton discover
Model for the on-site matrix elements of the tight-binding hamiltonian of a strained crystal: Application to silicon, germanium and their alloys
We discuss a model for the on-site matrix elements of the sp3d5s*
tight-binding hamiltonian of a strained diamond or zinc-blende crystal or
nanostructure. This model features on-site, off-diagonal couplings between the
s, p and d orbitals, and is able to reproduce the effects of arbitrary strains
on the band energies and effective masses in the full Brillouin zone. It
introduces only a few additional parameters and is free from any ambiguities
that might arise from the definition of the macroscopic strains as a function
of the atomic positions. We apply this model to silicon, germanium and their
alloys as an illustration. In particular, we make a detailed comparison of
tight-binding and ab initio data on strained Si, Ge and SiGe.Comment: Submitted to Phys. Rev.
Palaeolimnological reconstruction of Holocene climate variability in Lützow Holm Bay, East Antarctica
Late Holocene climate variability as recorded in an isolation basin in the Lützow Holm Bay region, East Antarctica
Determinants of ageism against older adults: a systematic review
Ageism is a widespread phenomenon and constitutes a significant threat to older people’s
well-being. Identifying the factors contributing to ageism is critical to inform policies that minimise its
societal impact. In this systematic review, we gathered and summarised empirical studies exploring
the key determinants of ageism against older people for a period of over forty years (1970–2017).
A comprehensive search using fourteen databases identified all published records related to the
umbrella concept of “ageism”. Reviewers independently screened the final pool to identify all papers
focusing on determinants, according to a predefined list of inclusion and exclusion criteria. All
relevant information was extracted and summarised following a narrative synthesis approach. A
total of 199 papers were included in this review. We identified a total of 14 determinants as robustly
associated with ageism. Of these, 13 have an effect on other-directed ageism, and one on self-directed
ageism. The quality of contact with older people and the positive or negative presentation of older
people to others emerged as the most robust determinants of other-directed ageism; self-directed
ageism is mostly determined by older adults’ health status. Given the correlational nature of most
studies included in this review, inferences on causality should be made cautiously.info:eu-repo/semantics/publishedVersio
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