79 research outputs found
Material-Specific Investigations of Correlated Electron Systems
We present the results of numerical studies for selected materials with
strongly correlated electrons using a combination of the local-density
approximation and dynamical mean-field theory (DMFT). For the solution of the
DMFT equations a continuous-time quantum Monte-Carlo algorithm was employed.
All simulations were performed on the supercomputer HLRB II at the Leibniz
Rechenzentrum in Munich. Specifically we have analyzed the pressure induced
metal-insulator transitions in Fe2O3 and NiS2, the charge susceptibility of the
fluctuating-valence elemental metal Yb, and the spectral properties of a
covalent band-insulator model which includes local electronic correlations.Comment: 14 pages, 7 figures, to appear in "High Performance Computing in
Science and Engineering, Garching 2009" (Springer
Electronic Structure Calculation by First Principles for Strongly Correlated Electron Systems
Recent trends of ab initio studies and progress in methodologies for
electronic structure calculations of strongly correlated electron systems are
discussed. The interest for developing efficient methods is motivated by recent
discoveries and characterizations of strongly correlated electron materials and
by requirements for understanding mechanisms of intriguing phenomena beyond a
single-particle picture. A three-stage scheme is developed as renormalized
multi-scale solvers (RMS) utilizing the hierarchical electronic structure in
the energy space. It provides us with an ab initio downfolding of the global
band structure into low-energy effective models followed by low-energy solvers
for the models. The RMS method is illustrated with examples of several
materials. In particular, we overview cases such as dynamics of semiconductors,
transition metals and its compounds including iron-based superconductors and
perovskite oxides, as well as organic conductors of kappa-ET type.Comment: 44 pages including 38 figures, to appear in J. Phys. Soc. Jpn. as an
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Mapping Philanthropic Foundations’ Characteristics: towards an international integrative framework of foundation types
As philanthropic foundations take on increasingly prominent sociopolitical roles, the need for stronger conceptualizations of foundations as an organizational form is articulated widely across academic, policy, and practice contexts. Building on institutional research’s tradition of categorizing, classifying and typologizing organizational forms, our article critically explores the different ways in which foundations have been cast and differentiated in international academic and practice literatures. Examining and integrating these, we propose an integrative framework of foundation types. Incorporating 13 categories—three contextual, five organizational, and five strategic ones—the framework allows for clarifying distinctions and identifying commonalities between different foundation forms, offering a basis for developing more reflective and differentiated research and practice knowledge
"They brought you back to the fact you're not the same": Sense of self after traumatic brain injury
This paper considers contexts following traumatic brain injury, exploring what may be at stake when dominant expectations predict a ‘lost’ or ‘broken’ self. I explore stories co-constructed with one young man and his mother to illustrate their personal and intersubjective understandings of identity, at times conflicting, within family interactions and when encountering normative practices of neurorehabilitation clinicians. The ower relations portrayed confront this man’s narrative attempts to align his present and pre-injury self, including standard assessments delineating change, administered by healthcare professionals. I consider a need for greater attention to interaction-generated disruption to sense of self, wthin contemporary conceptualisations of ‘person-centred care’
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