Spin-dependent thermoelectric transport coefficients in near-perfect quantum wires

Thermoelectric transport coefficients are determined for semiconductor quantum wires with weak thickness fluctuations. Such systems exhibit anomalies in conductance near 1/4 and 3/4 of 2e^2/h on the rising edge to the first conductance plateau, explained by singlet and triplet resonances of conducting electrons with a single weakly bound electron in the wire [T. Rejec, A. Ramsak, and J.H. Jefferson, Phys. Rev. B 62, 12985 (2000)]. We extend this work to study the Seebeck thermopower coefficient and linear thermal conductance within the framework of the Landauer-Buettiker formalism, which also exhibit anomalous structures. These features are generic and robust, surviving to temperatures of a few degrees. It is shown quantitatively how at elevated temperatures thermal conductance progressively deviates from the Wiedemann-Franz law.Comment: To appear in Phys. Rev. B 2002; 3 figure

Using Topological Statistics to Detect Determinism in Time Series

Statistical differentiability of the measure along the reconstructed trajectory is a good candidate to quantify determinism in time series. The procedure is based upon a formula that explicitly shows the sensitivity of the measure to stochasticity. Numerical results for partially surrogated time series and series derived from several stochastic models, illustrate the usefulness of the method proposed here. The method is shown to work also for high--dimensional systems and experimental time seriesComment: 23 RevTeX pages, 14 eps figures. To appear in Physical Review

Long-term exposures to air pollution and the risk of atrial fibrillation in the women’s health initiative cohort

BACKGROUND: Atrial fibrillation (AF) is associated with substantial morbidity and mortality. Short-term exposures to air pollution have been associated with AF triggering; less is known regarding associations between long-term air pollution exposures and AF incidence. OBJECTIVES: Our objective was to assess the association between long-term exposures to air pollution and distance to road on incidence of AF in a cohort of U.S. women. METHODS: We assessed the association of high resolution spatiotemporal model predictions of long-term exposures to particulate matter (PM10 and PM2:5 ), sulfur dioxide (SO2 ), nitrogen dioxide (NO2 ), and distance to major roads with incidence of AF diagnosis, identified through Medicare link-age, among 83,117 women in the prospective Women’s Health Initiative cohort, followed from enrollment in Medicare through December 2012, incidence of AF, or death. Using time-varying Cox proportional hazards models adjusted for age, race/ethnicity, study component, body mass index, physical activity, menopausal hormone therapy, smoking, diet quality, alcohol consumption, educational attainment, and neighborhood socioeconomic status, we estimated the relative risk of incident AF in association with each pollutant. RESULTS: A total of 16,348 incident AF cases were observed over 660,236 person-years of follow-up. Most exposure–response associations were non-linear. NO2 was associated with risk of AF in multivariable adjusted models [Hazard Ratio ðHRÞ = 1:18; 95% confidence interval (CI): 1.13, 1.24, comparing the top to bottom quartile, p-for-trend = < 0:0001]. Women living closer to roadways were at higher risk of AF (e.g., HR = 1:07; 95% CI: 1.01, 1.13 for living within 50 m of A3 roads, compared with ≥1,000 m, p-for-trend = 0:02), but we did not observe adverse associations with exposures to PM10, PM2:5, or SO2 . There were adverse associations with PM10 (top quartile HR = 1:10; 95% CI: 1.05, 1.16, p-for-trend = &lt; 0:0001) and PM2:5 (top quartile HR = 1:09; 95% CI: 1.03, 1.14, p-for-trend = 0:002) in sensitivity models adjusting for census region. DISCUSSION: In this study of postmenopausal women, NO2 and distance to road were consistently associated with higher risk of AF. https://doi.org/10.1289/EHP7683

Shadowing in Inelastic Scattering of Muons on Carbon, Calcium and Lead at Low XBj

Nuclear shadowing is observed in the per-nucleon cross-sections of positive muons on carbon, calcium and lead as compared to deuterium. The data were taken by Fermilab experiment E665 using inelastically scattered muons of mean incident momentum 470 GeV/c. Cross-section ratios are presented in the kinematic region 0.0001 < XBj <0.56 and 0.1 < Q**2 < 80 GeVc. The data are consistent with no significant nu or Q**2 dependence at fixed XBj. As XBj decreases, the size of the shadowing effect, as well as its A dependence, are found to approach the corresponding measurements in photoproduction.Comment: 22 pages, incl. 6 figures, to be published in Z. Phys.

Multi-ancestry transcriptome-wide association analyses yield insights into tobacco use biology and drug repurposing

Most transcriptome-wide association studies (TWASs) so far focus on European ancestry and lack diversity. To overcome this limitation, we aggregated genome-wide association study (GWAS) summary statistics, whole-genome sequences and expression quantitative trait locus (eQTL) data from diverse ancestries. We developed a new approach, TESLA (multi-ancestry integrative study using an optimal linear combination of association statistics), to integrate an eQTL dataset with a multi-ancestry GWAS. By exploiting shared phenotypic effects between ancestries and accommodating potential effect heterogeneities, TESLA improves power over other TWAS methods. When applied to tobacco use phenotypes, TESLA identified 273 new genes, up to 55% more compared with alternative TWAS methods. These hits and subsequent fine mapping using TESLA point to target genes with biological relevance. In silico drug-repurposing analyses highlight several drugs with known efficacy, including dextromethorphan and galantamine, and new drugs such as muscle relaxants that may be repurposed for treating nicotine addiction

Association of mitochondrial antioxidant enzymes with mitochondrial DNA as integral nucleoid constituents

Mitochondrial DNA (mtDNA) is organized in protein-DNA macrocomplexes called nucleoids. Average nucleoids contain 2–8 mtDNA molecules, which are organized by the histone-like mitochondrial transcription factor A. Besides well-characterized constituents, such as single-stranded binding protein or polymerase γ (Polγ), various other proteins with ill-defined functions have been identified. We report for the first time that mammalian nucleoids contain essential enzymes of an integral antioxidant system. Intact nucleoids were isolated with sucrose density gradients from rat and bovine heart as well as human Jurkat cells. Manganese superoxide dismutase (SOD2) was detected by Western blot in the nucleoid fractions. DNA, mitochondrial glutathione peroxidase (GPx1), and Polγ were coimmunoprecipitated with SOD2 from nucleoid fractions, which suggests that an antioxidant system composed of SOD2 and GPx1 are integral constituents of nucleoids. Interestingly, in cultured bovine endothelial cells the association of SOD2 with mtDNA was absent. Using a sandwich filter-binding assay, direct association of SOD2 by salt-sensitive ionic forces with a chemically synthesized mtDNA fragment was demonstrated. Increasing salt concentrations during nucleoid isolation on sucrose density gradients disrupted the association of SOD2 with mitochondrial nucleoids. Our biochemical data reveal that nucleoids contain an integral antioxidant system that may protect mtDNA from superoxide-induced oxidative damage.—Kienhöfer, J., Häussler, D. J. F., Ruckelshausen, F., Muessig, E., Weber, K., Pimentel, D., Ullrich, V., Bürkle, A., Bachschmid, M. M. Association of mitochondrial antioxidant enzymes with mitochondrial DNA as integral nucleoid constituents