Temperature dependence of the superconducting gap anisotropy in Bi2_{2}Sr2_{2}Ca1_{1}Cu2_{2}O8+x_{8+x}

We present the first detailed data of the momentum-resolved, temperature dependence of the superconducting gap of $Bi_{2}Sr_{2}Ca_{1}Cu_{2}O_{8+x}$, complemented by similar data on the intensity of the photoemission superconducting condensate spectral area. The gap anisotropy between the $\Gamma-\bar{M}$ and $\Gamma-X$ directions increases markedly with increasing temperature, contrary to what happens for conventional anisotropic-gap superconductors such as lead. Specifically, the size of the superconducting gap along the $\Gamma-X$ direction decreases to values indistinguishable from zero at temperatures for which the gap retains virtually full value along the $\Gamma-\bar{M}$ direction.Comment: APS_REVTEX. 19 pages, including 8 figures, available upon request. UW-Madison preprin

Observation of a van Hove Singularity in Bi2Sr2Ca1Cu2O8+xBi_{2}Sr_{2}Ca_{1}Cu_{2}O_{8+x} with Angle Resolved Photoemission

We have performed high energy resolution angle-resolved photoemission studies of the normal state band structure of oxygen overdoped $Bi_{2}Sr_{2}Ca_{1}Cu_{2}O_{8+x}$. We find that there is an extended saddle point singularity in the density of states along $\Gamma-\bar{M}-Z$ direction. The data also indicate that there is an asymmetry in the Fermi surface for both the $\Gamma-\bar{M}-Z$ and perpendicular directions.Comment: APS_Revtex. 28 pages, including 16 figures, available upon request. UW-Madison preprint#

Diffusion in pores and its dependence on boundary conditions

We study the influence of the boundary conditions at the solid liquid interface on diffusion in a confined fluid. Using an hydrodynamic approach, we compute numerical estimates for the diffusion of a particle confined between two planes. Partial slip is shown to significantly influence the diffusion coefficient near a wall. Analytical expressions are derived in the low and high confinement limits, and are in good agreement with numerical results. These calculations indicate that diffusion of tagged particles could be used as a sensitive probe of the solid-liquid boundary conditions.Comment: soumis \`a J.Phys. Cond. Matt. special issue on "Diffusion in Liquids, Polymers, Biophysics and Chemical Dynamics

Mass mortality or exceptional fossilization? The case of the early and middle Toarcian fossiliferous beds from the Digne-Les-Bains area (southeastern France)

La série sédimentaire d’âge domérien supérieur à toarcien supérieur (de –190 à –180 Ma) dans la Réserve Géologique de Haute-Provence (Sud-Est de la France) a l’intérêt de présenter deux types de gisements fossilifères remarquables. Le premier type, d’âge toarcien inférieur, a la particularité de présenter des restes d’ichtyosaures (dans au moins six sites) en plus de très nombreux autres fossiles. Le deuxième type, d’âge toarcien moyen, est caractérisé par l’abondance et la présence presque exclusive d’ammonites et de nautiles. Des études lithostratigraphiques, biostratigraphiques, paléontologiques, sédimentologiques et géochimiques, ont permis de savoir si ces accumulations résultaient de mortalité en masse ou bien si elles n’étaient dues qu’à des fossilisations exceptionnelles d’organismes à taux de mortalité normal. Les accumulations d’âge toarcien inférieur se sont effectuées, après mortalité normale, par piégeage avec des sédiments terrigènes dans des hémigrabens à la suite de jeu de blocs basculés et pendant une période d’anoxie ou d’hypoxie. Les gisements d’âge toarcien moyen correspondent à des condensations et concentrations fauniques lors de sédimentation carbonatée très réduite en liaison avec une transgression marine de grande ampleur. Diverses conditions, tectoniques locales de rifting, eustatiques régionales liées à l’évolution du domaine liguro-piémontais, océanographiques globales d’anoxie et de crise de production carbonatée, ont toutes joué un rôle dans la genèse des gisements fossilifères. Tout lien avec des extinctions massives, en rapport ou non avec des crises biologiques, est exclu

Pb0.4Bi1.6Sr2Ca1Cu2O8+xPb_{0.4}Bi_{1.6}Sr_{2}Ca_{1}Cu_{2}O_{8+x} and Oxygen Stoichiometry: Structure, Resistivity, Fermi Surface Topology and Normal State Properties

$Pb_{0.4}Bi_{1.6}Sr_2CaCu_2O_{8+x}$ ($Bi(Pb)-$2212) single crystal samples were studied using transmission electron microscopy (TEM), $ab-$plane ($\rho_{ab}$) and $c-$axis ($\rho_c$) resistivity, and high resolution angle-resolved ultraviolet photoemission spectroscopy (ARUPS). TEM reveals that the modulation in the $b-$axis for $Pb(0.4)-$doped $Bi(Pb)-$2212 is dominantly of $Pb-$type that is not sensitive to the oxygen content of the system, and the system clearly shows a structure of orthorhombic symmetry. Oxygen annealed samples exhibit a much lower $c-$axis resistivity and a resistivity minimum at $80-130$K. He-annealed samples exhibit a much higher $c-$axis resistivity and $d\rho_c/dT<0$ behavior below 300K. The Fermi surface (FS) of oxygen annealed $Bi(Pb)-$2212 mapped out by ARUPS has a pocket in the FS around the $\bar{M}$ point and exhibits orthorhombic symmetry. There are flat, parallel sections of the FS, about 60\% of the maximum possible along $k_x = k_y$, and about 30\% along $k_x = - k_y$. The wavevectors connecting the flat sections are about $0.72(\pi, \pi)$ along $k_x = k_y$, and about $0.80(\pi, \pi)$ along $k_x = - k_y$, rather than $(\pi,\pi)$. The symmetry of the near-Fermi-energy dispersing states in the normal state changes between oxygen-annealed and He-annealed samples.Comment: APS_REVTEX 3.0, 49 pages, including 11 figures, available upon request. Submitted to Phys. Rev. B

Visceral, subcutaneous abdominal adiposity and liver fat content distribution in normal glucose tolerance, impaired fasting glucose and/or impaired glucose tolerance

Q1Q1Objectives: To examine the specific distribution of liver fat content, visceral and subcutaneous adiposity in normal glucose tolerance (NGT/NGT), isolated impaired fasting glucose (iIFG), isolated impaired glucose tolerance (iIGT) and combined conditions (IFG+IGT), as well as with newly diagnosed type 2 diabetes (nT2D). Design: Multicenter, international observational study: cross-sectional analysis. Subjects: Two thousand five hundred and fifteen patients (50.0% women, 54.5% non-Caucasian) without previously known diabetes were recruited from 29 countries. Abdominal fat distribution was measured by computed tomography (CT). Liver fat was estimated using the CT-liver mean attenuation. Results: Compared with NGT/NGT patients, increased visceral adiposity was found in iIFG, iIGT, IFG+IGT and nT2D; estimated liver fat progressively increased across these conditions. A one-s.d. increase in visceral adiposity was associated with an increased risk of having iIFG (men: odds ratio (OR) 1.41 (95% confidence interval (CI) 1.15–1.74), women: OR 1.62 (1.29–2.04)), iIGT (men: OR 1.59 (1.15–2.01), women: OR 1.30 (0.96–1.76)), IFG+IGT (men: OR 1.64 (1.27–2.13), women: OR 1.83 (1.36–2.48)) and nT2D (men: OR 1.80 (1.35–2.42), women: OR 1.73 (1.25–2.41)). A one-s.d. increase in estimated liver fat was associated with iIGT (men: OR 1.46 (1.12–1.90), women: OR 1.81 (1.41–2.35)), IFG+IGT (men: OR 1.42 (1.14–1.77), women: OR 1.74 (1.35–2.26)) and nT2D (men: OR 1.77 (1.40–2.27), women: OR 2.38 (1.81–3.18)). Subcutaneous abdominal adipose tissue showed an inverse relationship with nT2D in women (OR 0.63 (0.45–0.88)). Conclusions: Liver fat was associated with iIGT but not with iIFG, whereas visceral adiposity was associated with both. Liver fat and visceral adiposity were associated with nT2D, whereas subcutaneous adiposity showed an inverse relationship with nT2D in women

Phenotyping progenies for complex architectural traits: a strategy for 1-year-old apple trees (Malus x domestica Borkh.)

International audienceThe aim of this study was to define a methodology for describing architectural traits in a quantitative way on tree descendants. Our strategy was to collect traits related to both tree structural organization, resulting from growth and branching, and tree form and then to select among these traits relevant descriptors on the basis of their genetic parameters. Because the complexity of tree architecture increases with tree age, we chose to describe the trees in the early stages of development. The study was carried out on a 1-year-old apple progeny derived from two parent cultivars with contrasted architecture. A large number of variables were collected at different positions and scales within the trees. Broad-sense heritability and genetic correlations were estimated and the within tree variability was analyzed for variables measured on long sylleptic axillary shoots (LSAS). These results were combined to select heritable and not correlated variables. Finally, the selection of variables proposed combines topological with geometric traits measured on both trunks and LSAS: (1) on the trunk, mean internode length, and number of sylleptic axillary shoots; (2) on axillary shoots, conicity, bending, and number of sylleptic axillary shoots born at order 3. The trees of the progeny were partitioned on the basis of these variables. The putative agronomic interest of the selected variables with respect to the subsequent tree development is discussed

French Pregnancy Physical Activity Questionnaire Compared with an Accelerometer Cut Point to Classify Physical Activity among Pregnant Obese Women

Given the high risk for inactivity during pregnancy in obese women, validated questionnaires for physical activity (PA) assessment in this specific population is required before evaluating the effect of PA on perinatal outcomes. No questionnaire was validated in pregnant obese women. The Pregnancy Physical Activity Questionnaire (PPAQ) has been designed based on activities reported during pregnancy and validated in pregnant women. We translated the PPAQ to French and assessed reliability and accuracy of this French version among pregnant obese women. In this cross-sectional study, pregnant obese women were evenly recruited at the end of each trimester of pregnancy. They completed the PPAQ twice, with an interval of 7 days in-between, to recall PA of the last three months. Between PPAQ assessments, participants wore an accelerometer (Actigraph GT1M) during 7 consecutive days. Fourty-nine (49) pregnant obese women (29.8±4.2 yrs, 34.7±5.1 kg.m−2) participated to the study. The intraclass correlation coefficients (ICCs) between the two PPAQ assessments were 0.90 for total activity, 0.86 for light and for moderate intensity, and 0.81 for vigorous intensity activities. It ranged from 0.59 for “Transportation” to 0.89 for “Household and Caregiving” activities. Spearman correlation coefficients (SCCs) between the PPAQ and the Matthews’ cut point used to classify an activity of moderate and above intensity were 0.50 for total activity, 0.25 for vigorous intensity and 0.40 for moderate intensity. The correlations between the PPAQ and the accelerometer counts were 0.58 for total activity, 0.39 for vigorous intensity and 0.49 for moderate intensity. The highest SCCs were for “Occupation” and “Household and Caregiving” activities. Comparisons with other standard cutpoints were presented in files S1, S2, S3, S4, S5, S6, S7. The PPAQ is reliable and moderately accurate for the measure of PA of various intensities and types among pregnant obese women

Transcriptional Analysis of Distant Signaling Induced by Insect Elicitors and Mechanical Wounding in Zea mays

When plants are under insect herbivore attack defensive measures are activated not only locally, but also in distant and systemic tissues. While insect elicitors (IE) abundant in the oral secretions of the attacking herbivore are essential in the regulation of induced defenses, little is known about their effects on systemic defense signaling in maize (Zea mays). The goal of this study was therefore to identify genetic markers that can be used to further characterize local and systemic signaling events induced by IE or mechanical wounding (MW). We selected genes for this study based on their putative involvement in signaling (allene oxide synthase), regulation of gene expression (transcription factor MYC7), and in direct defenses (ribosome inactivating protein) and analyzed their expression in different sections of the treated leaf as well as in systemic parts of the same plant. We found the most significant transcript accumulation of the selected genes after treatment with insect elicitors in those parts with increased JA levels. Additionally, treatment with IE did also induce the accumulation of MYC7 transcripts in basal parts of the treated leaf and systemically. MW, in contrast, did induce RIP and AOS only locally, but not MYC7. This local suppression of MYC7 was further studied by adding glutathione (GSH) as an electron donor to MW plants to quench putative α, β-unsaturated carbonyls, which build up to significant levels around the damage site. Indeed, GSH-treated MW plants accumulated MYC7 at the damage site and also produced more volatiles, suggesting a putative redox-regulatory element being involved in the suppression of MYC7. The results presented herein provide evidence for the specific induction of distant signaling events triggered by IE, most likely through electric signaling. Additionally, a putative role for MW-induced α, β-unsaturated carbonyls in the transcriptional regulation of defense genes was discovered

Differential Metabolisms of Green Leaf Volatiles in Injured and Intact Parts of a Wounded Leaf Meet Distinct Ecophysiological Requirements

Almost all terrestrial plants produce green leaf volatiles (GLVs), consisting of six-carbon (C6) aldehydes, alcohols and their esters, after mechanical wounding. C6 aldehydes deter enemies, but C6 alcohols and esters are rather inert. In this study, we address why the ability to produce various GLVs in wounded plant tissues has been conserved in the plant kingdom. The major product in completely disrupted Arabidopsis leaf tissues was (Z)-3-hexenal, while (Z)-3-hexenol and (Z)-3-hexenyl acetate were the main products formed in the intact parts of partially wounded leaves. 13C-labeled C6 aldehydes placed on the disrupted part of a wounded leaf diffused into neighboring intact tissues and were reduced to C6 alcohols. The reduction of the aldehydes to alcohols was catalyzed by an NADPH-dependent reductase. When NADPH was supplemented to disrupted tissues, C6 aldehydes were reduced to C6 alcohols, indicating that C6 aldehydes accumulated because of insufficient NADPH. When the leaves were exposed to higher doses of C6 aldehydes, however, a substantial fraction of C6 aldehydes persisted in the leaves and damaged them, indicating potential toxicity of C6 aldehydes to the leaf cells. Thus, the production of C6 aldehydes and their differential metabolisms in wounded leaves has dual benefits. In disrupted tissues, C6 aldehydes and their α,β-unsaturated aldehyde derivatives accumulate to deter invaders. In intact cells, the aldehydes are reduced to minimize self-toxicity and allow healthy cells to survive. The metabolism of GLVs is thus efficiently designed to meet ecophysiological requirements of the microenvironments within a wounded leaf