271 research outputs found

    Surface criticality and multifractality at localization transitions

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    We develop the concept of surface multifractality for localization-delocalization (LD) transitions in disordered electronic systems. We point out that the critical behavior of various observables related to wave functions near a boundary at a LD transition is different from that in the bulk. We illustrate this point with a calculation of boundary critical and multifractal behavior at the 2D spin quantum Hall transition and in a 2D metal at scales below the localization length.Comment: Published versio

    N-3 PUFAs induce inflammatory tolerance by formation of KEAP1-containing SQSTM1/p62-bodies and activation of NFE2L2

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    Inflammation is crucial in the defense against infections but must be tightly controlled to limit detrimental hyperactivation. Our diet influences inflammatory processes and omega-3 polyunsaturated fatty acids (n-3 PUFAs) have known anti-inflammatory effects. The balance of pro- and anti-inflammatory processes is coordinated by macrophages and macroautophagy/autophagy has recently emerged as a cellular process that dampens inflammation. Here we report that the n-3 PUFA docosahexaenoic acid (DHA) transiently induces cytosolic speckles of the autophagic receptor SQSTM1/p62 (sequestosome 1) (described as SQSTM1/p62-bodies) in macrophages. We suggest that the formation of SQSTM1/p62-bodies represents a fast mechanism of NFE2L2/Nrf2 (nuclear factor, erythroid 2 like 2) activation by recruitment of KEAP1 (kelch like ECH associated protein 1). Further, the autophagy receptor TAX1BP1 (Tax1 binding protein 1) and ubiquitin-editing enzyme TNFAIP3/A20 (TNF α induced protein 3) could be identified in DHA-induced SQSTM1/p62-bodies. Simultaneously, DHA strongly dampened the induction of pro-inflammatory genes including CXCL10 (C-X-C motif chemokine ligand 10) and we suggest that formation of SQSTM1/p62-bodies and activation of NFE2L2 leads to tolerance towards selective inflammatory stimuli. Finally, reduced CXCL10 levels were related to the improved clinical outcome in n-3 PUFA-supplemented heart-transplant patients and we propose CXCL10 as a robust marker for the clinical benefits mobilized by n-3 PUFA supplementation

    Wave function statistics and multifractality at the spin quantum Hall transition

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    The statistical properties of wave functions at the critical point of the spin quantum Hall transition are studied. The main emphasis is put onto determination of the spectrum of multifractal exponents Δq\Delta_q governing the scaling of moments ∼L−qd−Δq\sim L^{-qd-\Delta_q} with the system size LL and the spatial decay of wave function correlations. Two- and three-point correlation functions are calculated analytically by means of mapping onto the classical percolation, yielding the values Δ2=−1/4\Delta_2=-1/4 and Δ3=−3/4\Delta_3=-3/4. The multifractality spectrum obtained from numerical simulations is given with a good accuracy by the parabolic approximation Δq≃q(1−q)/8\Delta_q\simeq q(1-q)/8 but shows detectable deviations. We also study statistics of the two-point conductance gg, in particular, the spectrum of exponents XqX_q characterizing the scaling of the moments . Relations between the spectra of critical exponents of wave functions (Δq\Delta_q), conductances (XqX_q), and Green functions at the localization transition with a critical density of states are discussed.Comment: 16 pages, submitted to J. Phys. A, Special Issue on Random Matrix Theor

    Further Evidence for the Decay K+ to pi+ neutrino-antineutrino

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    Additional evidence for the rare kaon decay K+ to pi+ neutrino-antineutrino has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211<P<229 MeV/c, bringing the total for the combined data set to two. Including all data taken, the backgrounds were estimated to contribute 0.15 pm 0.05 events. The branching ratio is B=1.57^{+1.75}_{-0.82} 10^{-10}.Comment: 10 pages, 2 figure

    Aerosol optical properties in the North China Plain during HaChi campaign: an in-situ optical closure study

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    The largest uncertainty in the estimation of climate forcing stems from atmospheric aerosols. In early spring and summer of 2009, two periods of in-situ measurements on aerosol physical and chemical properties were conducted within the HaChi (Haze in China) project at Wuqing, a town between Beijing and Tianjin in the North China Plain (NCP). Aerosol optical properties, including the scattering coefficient (&amp;sigma;&lt;sub&gt;sp&lt;/sub&gt;), the hemispheric back scattering coefficient (&amp;sigma;&lt;sub&gt;bsp&lt;/sub&gt;), the absorption coefficient (&amp;sigma;&lt;sub&gt;ap&lt;/sub&gt;), as well as the single scattering albedo (ω), are presented. The diurnal and seasonal variations are analyzed together with meteorology and satellite data. The mean values of &amp;sigma;&lt;sub&gt;sp, 550 nm&lt;/sub&gt; of the dry aerosol in spring and summer are 280&amp;plusmn;253 and 379&amp;plusmn;251 Mm&lt;sup&gt;−1&lt;/sup&gt;, respectively. The average &amp;sigma;&lt;sub&gt;ap&lt;/sub&gt; for the two periods is respectively 47&amp;plusmn;38 and 43&amp;plusmn;27 Mm&lt;sup&gt;−1&lt;/sup&gt;. The mean values of &amp;omega; at the wavelength of 637 nm are 0.82&amp;plusmn;0.05 and 0.86&amp;plusmn;0.05 for spring and summer, respectively. The relative high levels of &amp;sigma;&lt;sub&gt;sp&lt;/sub&gt; and &amp;sigma;&lt;sub&gt;bsp&lt;/sub&gt; are representative of the regional aerosol pollution in the NCP. Pronounced diurnal cycle of $&amp;sigma;&lt;sub&gt;sp&lt;/sub&gt;, &amp;sigma;&lt;sub&gt;ap&lt;/sub&gt; and ω are found, mainly influenced by the evolution of boundary layer and the accumulation of local emissions during nighttime. The pollutants transported from the southwest of the NCP are more significant than that from the two megacities, Beijing and Tianjin, in both spring and summer. An optical closure experiment is conducted to better understand the uncertainties of the measurements. Good correlations (&lt;i&gt;R&lt;/i&gt;&gt;0.98) are found between the values measured by the nephelometer and the values calculated with a modified Mie model. The Monte Carlo simulation shows an uncertainty of about 30 % for the calculations. Considering all possible uncertainties of measurements, calculated &amp;sigma;&lt;sub&gt;sp&lt;/sub&gt; and &amp;sigma;&lt;sub&gt;bsp&lt;/sub&gt; agree well with the measured values, indicating a stable performance of instruments and thus reliable aerosol optical data
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