Assessing the operating temperature of multi-junction solar cells with novel rear side layer stack and local electrical contacts

Sub-bandgap sunlight provides a source of heat generation in solar cells that is detrimental to performance, especially in space applications where heat dissipation is limited. In this work we assess the impact that an advanced rear-side contact scheme for multi-junction solar cells has on the cell temperature. Our results show that this scheme reduces the optical power absorption below the bandgap of germanium by 81% compared to a standard, full metallization design. Measurements of the electrical and thermal power fluxes performed in vacuum demonstrate that this lower near-infrared light absorption results in 8% less heat dissipated in the cell with the novel rear-side contact scheme when operating at 25 ºC. Modelling of the operating temperature for both cells when fully encapsulated with glass indicates that this effect will also result in a reduction of the operating temperature of 9 ºC for the novel design

Fusion of SPOT5 multispectral and Ikonos panchromatic images

International audienceThe offer of high spectral and high spatial resolutions images has grown in the last decade. It is know possible to obtain data from different sources with different spatial and spec-tral resolutions. The field of data fusion of remotely sensed data grown also very fast in the last years. In this paper, an algorithm allowing the merging of SPOT 5 images and Ikonos images are proposed. This algorithm is based on the ARSIS concept and presents an implementation for a ratio of spatial resolution equal to 10. The ARSIS concept is first detailed. Then, the way of de-fining a new implementation based on this concept is presented, allowing to understand how to define new implementations and to develop new solutions based on this concept. The proposed algorithm is developed, describing the different steps for building a fused product from a SPOT 5 multispectral data at 10 m and from a IKONOS panchromatic data at 1 m. Some other methods are proposed. The evaluation of the quality of the different methods is achieved using a set of quantitative quality parameters. The visual quality of the products are evaluated by a set of inter-preters. Conclusions are drawn on the quality of the proposed products

Evaluation of the quality of Quickbird fused products

International audienceMost of the satellite sensors, presently operating in the optical domain, are providing a data set comprising multispectral images at a low spatial resolution and images at a higher spatial resolution but with a lower spectral content. The trend of satellite sensors is similar to the present situation. The idea of fusing multispectral images with a highest spatial resolution enables the creation of useful products for a set of applications. This paper aims at evaluating a set of methods for construction of synthetic multispectral images having a highest spatial resolution available within the data set. These methods are evaluated through the construction of fused products from a set of Quickbird panchromatic and multispectral images. Of interest are the most used methods: the Intensity-Hue-Saturation method, the Brovey transform, the multiplicative methods and a set of methods derived from the ARSIS concept. The different methods are shortly presented. These methods are tested in a dataset from the area of Madrid. The dataset proposed a good diversity of landscape allowing the measure of the impact of fusion methods on different cases. The resulting images are evaluated through visual criteria from a set of photointerpreters. They classified the fused products and pro-vided a ranking for the visual quality. Then the proposed protocol defined by Wald et al. (1997) is applied to all methods. A set of quantitative parameters is computed allowing an objective comparison of the results. Finally a new parameter allowing the quantification of the information brought by the fusion method is proposed. This parameter is based on the analysis of the difference of the real structures of a multispectral image and of the computed structures of the fused products. It is applied to the different methods and favors the evaluation of the impact of an algorithm on the resulting images. Some conclusions are drawn on the ranking of the different methods and on the appropriate parameters for the evaluation of the quality of fused products

Contact transmission of influenza virus between ferrets imposes a looser bottleneck than respiratory droplet transmission allowing propagation of antiviral resistance

Influenza viruses cause annual seasonal epidemics and occasional pandemics. It is important to elucidate the stringency of bottlenecks during transmission to shed light on mechanisms that underlie the evolution and propagation of antigenic drift, host range switching or drug resistance. The virus spreads between people by different routes, including through the air in droplets and aerosols, and by direct contact. By housing ferrets under different conditions, it is possible to mimic various routes of transmission. Here, we inoculated donor animals with a mixture of two viruses whose genomes differed by one or two reverse engineered synonymous mutations, and measured the transmission of the mixture to exposed sentinel animals. Transmission through the air imposed a tight bottleneck since most recipient animals became infected by only one virus. In contrast, a direct contact transmission chain propagated a mixture of viruses suggesting the dose transferred by this route was higher. From animals with a mixed infection of viruses that were resistant and sensitive to the antiviral drug oseltamivir, resistance was propagated through contact transmission but not by air. These data imply that transmission events with a looser bottleneck can propagate minority variants and may be an important route for influenza evolution

Mineralogical characterization of silica sinters from the El Tatio geothermal field, Chile

11 páginas.Silica sinters, deposited from alkali chloride waters in the El Tatio geothermal field in northern Chile (22°20'S, 68°01'W), have been characterized by XRD, SEM, TG-DTA, and FTIR. The dominant silica phase is opal-A. Minor contents of opal-A/-CT and opal-CT are also present together with halite (NaCl), sylvite (KCl), and realgar (AsS). Accessory phases include teruggite [Ca4MgAs2B12O22(OH)12·12(H2O)], sassolite (H3BO3), and detrital quartz (SiO2). FWHM values reflect the immature nature of the studied opal-A. DTA heating experiments of opal-A show cristobalite crystallization at ~1000 °C, whereas DTA cooling experiments show the β -alfacristobalite transformation at ~200 °C. The total weight loss is related to changes in the sinter microtextures, mineral phases, and organic matter contents. FTIR spectra show the effects of silica maturation as consequence of the loss of trapped and absorbed water attached to silanols.Peer reviewe

A semantic interoperability approach to support integration of gene expression and clinical data in breast cancer

[Abstract] Introduction. The introduction of omics data and advances in technologies involved in clinical treatment has led to a broad range of approaches to represent clinical information. Within this context, patient stratification across health institutions due to omic profiling presents a complex scenario to carry out multi-center clinical trials. Methods. This paper presents a standards-based approach to ensure semantic integration required to facilitate the analysis of clinico-genomic clinical trials. To ensure interoperability across different institutions, we have developed a Semantic Interoperability Layer (SIL) to facilitate homogeneous access to clinical and genetic information, based on different well-established biomedical standards and following International Health (IHE) recommendations. Results. The SIL has shown suitability for integrating biomedical knowledge and technologies to match the latest clinical advances in healthcare and the use of genomic information. This genomic data integration in the SIL has been tested with a diagnostic classifier tool that takes advantage of harmonized multi-center clinico-genomic data for training statistical predictive models. Conclusions. The SIL has been adopted in national and international research initiatives, such as the EURECA-EU research project and the CIMED collaborative Spanish project, where the proposed solution has been applied and evaluated by clinical experts focused on clinico-genomic studies.Instituto de Salud Carlos III, PI13/02020Instituto de Salud Carlos III, PI13/0028