Application of time-dependent density functional theory to optical activity

As part of a general study of the time-dependent local density approximation (TDLDA), we here report calculations of optical activity of chiral molecules. The theory automatically satisfies sum rules and the Kramers-Kronig relation between circular dichroism and optical rotatory power. We find that the theory describes the measured circular dichroism of the lowest states in methyloxirane with an accuracy of about a factor of two. In the chiral fullerene C_76 the TDLDA provides a consistent description of the optical absorption spectrum, the circular dichroism spectrum, and the optical rotatory power, except for an overall shift of the theoretical spectrum.Comment: 17 pages and 13 PostScript figure

Parallel computation of 3-D soil-structure interaction in time domain with a coupled FEM/SBFEM approach

The final publication is available at Springer via http://dx.doi.org/10.1007/s10915-011-9551-xThis paper introduces a parallel algorithm for the scaled boundary finite element method (SBFEM). The application code is designed to run on clusters of computers, and it enables the analysis of large-scale soil-structure-interaction problems, where an unbounded domain has to fulfill the radiation condition for wave propagation to infinity. The main focus of the paper is on the mathematical description and numerical implementation of the SBFEM. In particular, we describe in detail the algorithm to compute the acceleration unit impulse response matrices used in the SBFEM as well as the solvers for the Riccati and Lyapunov equations. Finally, two test cases validate the new code, illustrating the numerical accuracy of the results and the parallel performances. © Springer Science+Business Media, LLC 2011.Jose E. Roman and Enrique S. Quintana-Orti were partially supported by the Spanish Ministerio de Ciencia e Innovacion under grants TIN2009-07519, and TIN2008-06570-C04-01, respectively.Schauer, M.; Román Moltó, JE.; Quintana Orti, ES.; Langer, S. (2012). Parallel computation of 3-D soil-structure interaction in time domain with a coupled FEM/SBFEM approach. Journal of Scientific Computing. 52(2):446-467. doi:10.1007/s10915-011-9551-xS446467522Anderson, E., Bai, Z., Bischof, C., Demmel, J., Dongarra, J., Croz, J.D., Greenbaum, A., Hammarling, S., McKenney, A., Sorensen, D.: LAPACK User’s Guide. Society for Industrial and Applied Mathematics, Philadelphia (1992)Antes, H., Spyrakos, C.: Soil-structure interaction. In: Beskos, D., Anagnotopoulos, S. (eds.) Computer Analysis and Design of Earthquake Resistant Structures, p. 271. Computational Mechanics Publications, Southampton (1997)Appelö, D., Colonius, T.: A high-order super-grid-scale absorbing layer and its application to linear hyperbolic systems. J. Comput. 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Biomedical colonialism or local autonomy?: local healers in the fight against tuberculosis

Analiza el papel de los agentes médicos autóctonos y sus conocimientos en las campañas antituberculosas contemporáneas en el África subsahariana. Sitúa la medicina contemporánea, llevada a cabo en África en la herencia cultural de la medicina colonial, para comprender el marco histórico en el que se desarrollaron, a partir de los años setenta del siglo XX, las estrategias de la Organización Mundial de la Salud de promoción y desarrollo de las medicinas 'tradicionales'. En los proyectos sanitarios analizados, se evalúan las prácticas médicas locales y se entrenan a los agentes autóctonos para integrarlos en actividades estrictamente biomédicas: identificación de síntomas, remisión a hospitales o supervisión de tratamientos farmacológicos.The article explores the role played by indigenous medical agents, and their knowledge, within contemporary tuberculosis campaigns in sub-Saharan Africa. To understand the historical framework within which the World Health Organization devised its strategies to promote and develop traditional medicine as of the 1970s, the article contextualizes contemporary medicine as a cultural legacy of colonial medicine. Under the public healthcare projects analyzed in the article, local medical practices were assessed and indigenous agents trained so they could take part in strictly biomedical activities, like symptom identification, referrals to hospitals, or supervision of drug treatments.Trabajo realizado para la obtención del Diploma de Estudios Avanzados (DEA) en el programa de doctorado Salud: Antropología e Historia, bajo la dirección de la profesora Rosa María Medina Doménech

Identification of common genetic risk variants for autism spectrum disorder

Autism spectrum disorder (ASD) is a highly heritable and heterogeneous group of neurodevelopmental phenotypes diagnosed in more than 1% of children. Common genetic variants contribute substantially to ASD susceptibility, but to date no individual variants have been robustly associated with ASD. With a marked sample-size increase from a unique Danish population resource, we report a genome-wide association meta-analysis of 18,381 individuals with ASD and 27,969 controls that identified five genome-wide-significant loci. Leveraging GWAS results from three phenotypes with significantly overlapping genetic architectures (schizophrenia, major depression, and educational attainment), we identified seven additional loci shared with other traits at equally strict significance levels. Dissecting the polygenic architecture, we found both quantitative and qualitative polygenic heterogeneity across ASD subtypes. These results highlight biological insights, particularly relating to neuronal function and corticogenesis, and establish that GWAS performed at scale will be much more productive in the near term in ASD.Peer reviewe

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

Mortgage product innovation in advanced economies: more choice, more risk

In many developed countries, house prices have been rising rapidly, mortgage debt has been increasing and affordability has worsened. It is in this context that the standard annuity mortgage is increasingly being supplanted by mortgages with non-standard features, such as longer terms or interest-only payments. Many of these new features aim to reduce the borrower's monthly debt service in the initial period of the loan. While these new mortgage types help households to enter owner-occupation and to vary their expenditure patterns, the long-term cost to the borrower cannot normally be less than for a standard product. Moreover, such mortgages can also be more risky: the interest-only borrower does not accumulate equity as an annuity borrower does, and loans with longer terms expose the borrower to greater risk of interest-rate or other economic shocks. As a result both borrowers pay more and the housing finance system may be more fragile. This paper brings together evidence from 13 developed countries about house prices, debt and affordability, and particularly the availability and market share of mortgages with these new features. It analyses trends over the last ten years and discusses the risks of these mortgages compared to standard annuity products