All Inequalities for the Relative Entropy

The relative entropy of two n-party quantum states is an important quantity exhibiting, for example, the extent to which the two states are different. The relative entropy of the states formed by reducing two n-party to a smaller number $m$ of parties is always less than or equal to the relative entropy of the two original n-party states. This is the monotonicity of relative entropy. Using techniques from convex geometry, we prove that monotonicity under restrictions is the only general inequality satisfied by relative entropies. In doing so we make a connection to secret sharing schemes with general access structures. A suprising outcome is that the structure of allowed relative entropy values of subsets of multiparty states is much simpler than the structure of allowed entropy values. And the structure of allowed relative entropy values (unlike that of entropies) is the same for classical probability distributions and quantum states.Comment: 15 pages, 3 embedded eps figure

The genetic architecture of the human cerebral cortex

INTRODUCTION The cerebral cortex underlies our complex cognitive capabilities. Variations in human cortical surface area and thickness are associated with neurological, psychological, and behavioral traits and can be measured in vivo by magnetic resonance imaging (MRI). Studies in model organisms have identified genes that influence cortical structure, but little is known about common genetic variants that affect human cortical structure. RATIONALE To identify genetic variants associated with human cortical structure at both global and regional levels, we conducted a genome-wide association meta-analysis of brain MRI data from 51,665 individuals across 60 cohorts. We analyzed the surface area and average thickness of the whole cortex and 34 cortical regions with known functional specializations. RESULTS We identified 306 nominally genome-wide significant loci (P < 5 × 10−8) associated with cortical structure in a discovery sample of 33,992 participants of European ancestry. Of the 299 loci for which replication data were available, 241 loci influencing surface area and 14 influencing thickness remained significant after replication, with 199 loci passing multiple testing correction (P < 8.3 × 10−10; 187 influencing surface area and 12 influencing thickness). Common genetic variants explained 34% (SE = 3%) of the variation in total surface area and 26% (SE = 2%) in average thickness; surface area and thickness showed a negative genetic correlation (rG = −0.32, SE = 0.05, P = 6.5 × 10−12), which suggests that genetic influences have opposing effects on surface area and thickness. Bioinformatic analyses showed that total surface area is influenced by genetic variants that alter gene regulatory activity in neural progenitor cells during fetal development. By contrast, average thickness is influenced by active regulatory elements in adult brain samples, which may reflect processes that occur after mid-fetal development, such as myelination, branching, or pruning. When considered together, these results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness. To identify specific genetic influences on individual cortical regions, we controlled for global measures (total surface area or average thickness) in the regional analyses. After multiple testing correction, we identified 175 loci that influence regional surface area and 10 that influence regional thickness. Loci that affect regional surface area cluster near genes involved in the Wnt signaling pathway, which is known to influence areal identity. We observed significant positive genetic correlations and evidence of bidirectional causation of total surface area with both general cognitive functioning and educational attainment. We found additional positive genetic correlations between total surface area and Parkinson’s disease but did not find evidence of causation. Negative genetic correlations were evident between total surface area and insomnia, attention deficit hyperactivity disorder, depressive symptoms, major depressive disorder, and neuroticism. CONCLUSION This large-scale collaborative work enhances our understanding of the genetic architecture of the human cerebral cortex and its regional patterning. The highly polygenic architecture of the cortex suggests that distinct genes are involved in the development of specific cortical areas. Moreover, we find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function

KINETICS OF GLASS FORMATION AND DEVITRIFICATION BEHAVIOR

La formation du verre est considérée sous un aspect cinétique. La cinétique de nucléation, aussi bien homogène qu'hétérogène, ainsi que la croissance du cristal sont initialement suivies. Les informations obtenues dans ces domaines sont réunies avec des traitements de cristallisation pendant un refroidissement constant afin d'évaluer des vitesses critiques de refroidissement nécessaires à la formation de verres de différents matériaux. Les paramètres du matériau contribuant à la formation et au procédé de cristallisation à chaud du verre sont considérés. Le traitement cinétique est aussi utilisé pour décrire d'autres phénomènes comme les effets d'hétérogénéités de nucléation sur la formation du verre et l'utilisation d'expériences de DTA pour évaluer les barrières de la nucléation du cristal.The process of glass formation is viewed from a kinetic perspective. Initial attention is directed to the kinetics of nucleation, both homogeneous and heterogeneous, and of crystal growth. Information obtained in these areas is combined with treatments of crystallization during continuous cooling to evaluate the critical cooling rates required to form glasses of various materials. Consideration is given to the material parameters which are conducive to glass formation, and to the process of crystallization on reheating of glass. The kinetic treatment is also used to describe other phenomena such as the effects of nucleating heterogeneities on glass formation and the use of DTA experiments to evaluate the barriers to crystal nucleation

IMIDE SILANES-ADHESION PROMOTERS FOR POLYIMIDE

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STRUCTURE OF SODIUM ALUMINOSILICATE GLASSES : X-RAY PHOTOELECTRON SPECTROSCOPY

Plusieurs séries de verre d'aluminosilicate de sodium ont été étudiées par spectroscopie des photoélectrons X (XPS) de l'oxygène. Les spectres sont interprétés sur la base de l'existence de 3 types d'environnement de l'oxygène : des oxygènes pontants symétriques BO1 (Si-O-Si), des oxygènes pontants asymétriques BO2 (Si-O-Al) et des oxygènes non-pontants NBO (Si-O-, Na+) . Les résultats sont compatibles avec la théorie classique qui prédit que la fraction d'oxygène non-pontant tend vers zéro quand le rapport Al/Na croît de 0 à 1, et que le rapport BO2/BO1 croît constamment.X-ray photoelectron spectroscopy (X.P.S) of the oxygen O1S spectra has been measured in several series of sodium alumino silicate glasses. The spectra are interpreted in terms of 3 types of oxygen environment : - a symmetric bridging oxygen - BO1 (Si-O-Si), an assymmetric bridging oxygen - BO2 (Si-O-Al), and a non-bridging oxygen - NBO (Si-O-, Na+). The results are in agreement with the classical theory which predicts that the fraction of non-bridging oxygen atoms fNBO → 0 as Al/Na increases from zero to unity, and the ratio BO2/BO1 steadily increases

Electrochromic glazing

Commercialization of large-area electrochromic glazing is reviewed with respect to device configuration and materials employed. Device configurations including electrochromic solutions and solid state electrochromic layers are discussed as well as novel user-controlled photochromic and gasochromic devices

STRUCTURE OF SODIUM ALUMINOSILICATE GLASSES : T1 LUMINESCENCE SPECTROSCOPY

Les spectres optiques des ions Tl+, correspondant à une émission à 350 nm, ont été mesurés dans des verres d'aluminosilicate de sodium. Les spectres mettent en évidence deux contributions dues respectivement à T1+ agissant comme modifieur du réseau ou comme compensateur de charge pour l'aluminium. Quand le rapport Al/Na devient plus grand que 1, le spectre de compensation de charge est seul observé. En dessous de 1, le spectre de modifieur du réseau prend de plus en plus d'importance quand Al/Na décroît. Ceci est bien en accord avec le modèle traditionnel des structures d'aluminosilicate alcalins, où la composition critique pour la disparition des oxygènes non-pontants est donnée par Al/Na = 1.Optical excitation spectra of Tl+ ions, corresponding to emission at 350 nm, have been measured in Na aluminosilicate glasses. The excitation spectra are shown to be superpositions of two primary spectra, which are identified with T1+ acting as network modifiers or as charge compensators for network aluminums. When Al/Na ≥ 1, only the charge compensator spectrum can be observed. As Al/Na decreases below unity, the fraction of the charge compensator spectrum decreases rapidly, and the fraction of the network modifier spectrum increases correspondingly. These results strongly support the traditional model of alkali aluminosilicate structure, in which the critical compositions for (dis)appearance of nonbridging oxygens are given by Al/Na = 1 ; they contradict reports of XPS measurements from which it had been concluded that the critical compositions are given by Al/Na ≈ 0.7. The network modifier spectra do not depend strongly on glass composition, whereas the charge compensator peaks vary significantly with composition. These results are fully consistant with new oxygen is XPS spectra