839 research outputs found
Anderson-Hubbard model with box disorder: Statistical dynamical mean-field theory investigation
Strongly correlated electrons with box disorder in high-dimensional lattices
are investigated. We apply the statistical dynamical mean-field theory, which
treats local correlations non-perturbatively. The incorporation of a finite
lattice connectivity allows for the detection of disorder-induced localization
via the probability distribution function of the local density of states. We
obtain a complete paramagnetic ground state phase diagram and find
correlation-induced as well as disorder-induced metal-insulator transitions.
Our results qualitatively confirm predictions obtained by typical medium
theory. Moreover, we find that the probability distribution function of the
local density of states in the metallic phase strongly deviates from a
log-normal distribution as found for the non-interacting case.Comment: 13 pages, 15 figures, published versio
Green bonds, transition to a low-carbon economy, and intergenerational fairness: Evidence from an extended DICE model
Perceived intergenerational unfairness is one of the obstacles for a rapid transition to a low carbon economy whereby current generations have to carry the burden of paying for mitigation, while the next generations will enjoy the benefits for free. Green bonds are believed to be able to distribute the burdens over generations more evenly. In this paper, we examine whether green bonds can indeed resolve the intergenerational inequity challenge. To do so, we employ the DICE model and supplement it with bonds and green tax through which future generations repay the debt. We show that bonds can reduce but cannot completely eliminate the intergenerational inequities. Lower interest rates shorten the initial time period when the society is worse off if a mitigation policy is implemented. Additional compensation mechanisms ensuring that the current generation retains the consumption level equal to the one without mitigation are needed to achieve a Pareto improvement of the mitigation scenario for all generations
The earth's climate at the end of the century
Local climate is dependent on the global climate. Here, a global picture on climate change is presented using predictions from the EC-Earth simulations for the end of the century. The results indicate a general rise in annual mean temperature everywhere: 2-4 degrees (global average), 1-6 degrees (over Europe) and 1-4 degrees (Ireland). Changes in precipitation are more varied: large increases (>100%) at high northern latitudes and in the equatorial Pacific but decreases of more than 50% over the subtropics; winters in Europe are predicted to be up to 20% wetter and summers up to 20% drier. Changes in extremes are also presented in this chapter
Localization of correlated fermions in optical lattices with speckle disorder
Strongly correlated fermions in three- and two-dimensional optical lattices
with experimentally realistic speckle disorder are investigated. We extend and
apply the statistical dynamical mean-field theory, which treats local
correlations non-perturbatively, to incorporate on-site and hopping-type
randomness on equal footing. Localization due to disorder is detected via the
probability distribution function of the local density of states. We obtain a
complete paramagnetic ground state phase diagram for experimentally realistic
parameters and find a strong suppression of the correlation-induced metal
insulator transition due to disorder. Our results indicate that the
Anderson-Mott and the Mott insulator are not continuously connected due to the
specific character of speckle disorder. Furthermore, we discuss the effect of
finite temperature on the single-particle spectral function.Comment: 12 pages, 16 figures, published versio
Memorandum on a new financial architecture and new regulations
The financial crisis is global and is deeply rooted in a decade-long misuse of the financial market for rent-seeking. The financial industry has largely abandoned its role as a service industry, supposedly charging reasonable fees for the services of spreading risk and allocating capital and credit. Instead it provides a market for corporate control āmergers and acquisitionsā and a casino for betting on or hedging practically any kind of risk āthe derivatives marketā.Publisher's Versio
Priming theta burst stimulation enhances motor cortex plasticity in young but not old adults
Abstract not availableGeorge M. Opie, Eleni Vosnakis, Michael C. Ridding, Ulf Ziemann, John G. Semmle
Efficient Elimination of Inhaled Nanoparticles from the Alveolar Region: Evidence for Interstitial Uptake and Subsequent Reentrainment onto Airways Epithelium
BACKGROUND: There is ongoing discussion that inhaled nanoparticles (NPs, < 100 nm) may translocate from epithelial deposition sites of the lungs to systemic circulation. OBJECTIVES AND METHODS: We studied the disappearance of NPs from the epithelium by sequential lung retention and clearance and bronchoalveolar lavage (BAL) measurements in healthy adult Wistar Kyoto (WKY) rats at various times over 6 months after administration of a single 60- to 100-min intratracheal inhalation of iridium-192 ((192)Ir)āradiolabeled NPs. A complete (192)Ir balance of all organs, tissues, excretion, remaining carcass, and BAL was performed at each time point. RESULTS: Directly after inhalation we found free NPs in the BAL; later, NPs were predominantly associated with alveolar macropages (AMs). After 3 weeks, lavageable NP fractions decreased to 0.06 of the actual NP lung burden. This is in stark contrast to the AM-associated fraction of micron-sized particles reported in the literature. These particles remained constant at about 0.8 throughout a 6-month period. Three weeks after inhalation, 80% of the retained Ir NPs was translocated into epithelium and interstitium. CONCLUSION: There is a strong size-selective difference in particle immobilization. Furthermore, AM-mediated NP transport to the larynx originates not only from the NP fraction retained on the epithelium but also from NPs being reentrained from the interstitium to the luminal side of epithelium. We conclude that NPs are much less phagocytized by AMs than large particles but are effectively removed from the lung surface into the interstitium. Even from these interstitial sites, they undergo AM-mediated long-term NP clearance to the larynx
The selective phosphodiesterase 4 inhibitor roflumilast and phosphodiesterase 3/4 inhibitor pumafentrine reduce clinical score and TNF expression in experimental colitis in mice.
The specific inhibition of phosphodiesterase (PDE)4 and dual inhibition of PDE3 and PDE4 has been shown to decrease inflammation by suppression of pro-inflammatory cytokine synthesis. We examined the effect of roflumilast, a selective PDE4 inhibitor marketed for severe COPD, and the investigational compound pumafentrine, a dual PDE3/PDE4 inhibitor, in the preventive dextran sodium sulfate (DSS)-induced colitis model. The clinical score, colon length, histologic score and colon cytokine production from mice with DSS-induced colitis (3.5% DSS in drinking water for 11 days) receiving either roflumilast (1 or 5 mg/kg body weight/d p.o.) or pumafentrine (1.5 or 5 mg/kg/d p.o.) were determined and compared to vehicle treated control mice. In the pumafentrine-treated animals, splenocytes were analyzed for interferon-Ī³ (IFNĪ³) production and CD69 expression. Roflumilast treatment resulted in dose-dependent improvements of clinical score (weight loss, stool consistency and bleeding), colon length, and local tumor necrosis factor-Ī± (TNFĪ±) production in the colonic tissue. These findings, however, were not associated with an improvement of the histologic score. Administration of pumafentrine at 5 mg/kg/d alleviated the clinical score, the colon length shortening, and local TNFĪ± production. In vitro stimulated splenocytes after in vivo treatment with pumafentrine showed a significantly lower state of activation and production of IFNĪ³ compared to no treatment in vivo. These series of experiments document the ameliorating effect of roflumilast and pumafentrine on the clinical score and TNF expression of experimental colitis in mice
Correlated electrons in the presence of disorder
Several new aspects of the subtle interplay between electronic correlations
and disorder are reviewed. First, the dynamical mean-field theory
(DMFT)together with the geometrically averaged ("typical") local density of
states is employed to compute the ground state phase diagram of the
Anderson-Hubbard model at half-filling. This non-perturbative approach is
sensitive to Anderson localization on the one-particle level and hence can
detect correlated metallic, Mott insulating and Anderson insulating phases and
can also describe the competition between Anderson localization and
antiferromagnetism. Second, we investigate the effect of binary alloy disorder
on ferromagnetism in materials with -electrons described by the periodic
Anderson model. A drastic enhancement of the Curie temperature caused by
an increase of the local -moments in the presence of disordered conduction
electrons is discovered and explained.Comment: 17 pages, 7 figures, final version, typos corrected, references
updated, submitted to Eur. Phys. J. for publication in the Special Topics
volume "Cooperative Phenomena in Solids: Metal-Insulator Transitions and
Ordering of Microscopic Degrees of Freedom
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