60,637 research outputs found
Effects of extended impurity perturbation in d-wave superconductor
We describe the effects of electronic perturbation distributed on nearest
neighbor sites to the impurity center in a planar \textit{d}-wave
superconductor, in approximation of circular Fermi surface. Alike the behavior
previously reported for point-like perturbation and square Fermi surface, the
quasiparticle density of states can display a resonance
inside the gap (and very weak features from low symmetry representations of
non-local perturbation) and asymptotically vanishes at as
. The local suppression of SC order parameter
in this model is found to be somewhat weaker than for an equivalent point-like
(non-magnetic) perturbation and much weaker than for a spin-dependent
(extended) perturbation.Comment: 7 pages, 5 figures, some minor typos and the curves in Fig. 5
correcte
Shareholder Engagement and Chevron’s Policy 520 on Human Rights: The Role Played by the United States Jesuit Conference’s “National Jesuit Committee on Investment Responsibility”
Purpose
To demonstrate how the Society of Jesus (Jesuits) in the United States through the “National Jesuit Committee on Investment Responsibility” played a significant role as a socially conscious institutional and religious investor in influencing Chevron’s Human Rights Policy 520 and to analyze the factors that contributed to a successful shareholder engagement with the company.
Methodology/approach
Case study based on firsthand information.
Findings
Our conclusion offers support for Allen et al.’s (2012) conclusion of legitimacy (credibility) being the dominant force in a successful engagement.
We found that coalition-building is a significant moderating variable in increasing shareholder salience. This finding contradicts the study by Gifford (2010).
Originality/value of chapter
The chapter is based on the actual process of shareholder engagement with Chevron Corporation that led to the human rights policy and is written mainly based on firsthand information
Hydrogen storage in the form of metal hydrides
Reversible reactions between hydrogen and such materials as iron/titanium and magnesium/ nickel alloy may provide a means for storing hydrogen fuel. A demonstration model of an iron/titanium hydride storage bed is described. Hydrogen from the hydride storage bed powers a converted gasoline electric generator
Coordinated balancing of muscle oxidative metabolism through PGC-1α increases metabolic flexibility and preserves insulin sensitivity
The peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) enhances oxidative metabolism in skeletal muscle. Excessive lipid oxidation and electron transport chain activity can, however, lead to the accumulation of harmful metabolites and impair glucose homeostasis. Here, we investigated the effect of over-expression of PGC-1α on metabolic control and generation of insulin desensitizing agents in extensor digitorum longus (EDL), a muscle that exhibits low levels of PGC-1α in the untrained state and minimally relies on oxidative metabolism. We demonstrate that PGC-1α induces a strictly balanced substrate oxidation in EDL by concomitantly promoting the transcription of activators and inhibitors of lipid oxidation. Moreover, we show that PGC-1α enhances the potential to uncouple oxidative phosphorylation. Thereby, PGC-1α boosts elevated, yet tightly regulated oxidative metabolism devoid of side products that are detrimental for glucose homeostasis. Accordingly, PI3K activity, an early phase marker for insulin resistance, is preserved in EDL muscle. Our findings suggest that PGC-1α coordinately coactivates the simultaneous transcription of gene clusters implicated in the positive and negative regulation of oxidative metabolism and thereby increases metabolic flexibility. Thus, in mice fed a normal chow diet, over-expression of PGC-1α does not alter insulin sensitivity and the metabolic adaptations elicited by PGC-1α mimic the beneficial effects of endurance training on muscle metabolism in this context
Abundance ratios of volatile vs. refractory elements in planet-harbouring stars: hints of pollution?
We present the [X/H] trends as function of the elemental condensation
temperature Tc in 88 planet host stars and in a volume-limited comparison
sample of 33 dwarfs without detected planetary companions. We gathered
homogeneous abundance results for many volatile and refractory elements
spanning a wide range of Tc, from a few dozens to several hundreds kelvin. We
investigate possible anomalous trends of planet hosts with respect to
comparison sample stars in order to detect evidence of possible pollution
events. No significant differences are found in the behaviour of stars with and
without planets. This result is in agreement with a ``primordial'' origin of
the metal excess in planet host stars. However, a subgroup of 5 planet host and
1 comparison sample stars stands out for having particularly high [X/H] vs. Tc
slopes.Comment: 10 pages, 7 figures, accepted for publication in A&A. Figures with
higher resolution are available at www.iac.es/proyect/abuntes
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