The role of endosymbionts in the evolution of haploid-male genetic systems in scale insects (Coccoidea)

There is an extraordinary diversity in genetic systems across species, but this variation remains poorly understood. In part, this is because the mechanisms responsible for transitions between systems are often unknown. A recent hypothesis has suggested that conflict between hosts and endosymbiotic microorganisms over transmission could drive the transition from diplodiploidy to systems with male haploidy (haplodiploidy, including arrhenotoky and paternal genome elimination [PGE]). Here, we present the first formal test of this idea with a comparative analysis across scale insects (Hemiptera: Coccoidea). Scale insects are renowned for their large variation in genetic systems, and multiple transitions between diplodiploidy and haplodiploidy have taken place within this group. Additionally, most species rely on endosymbiotic microorganisms to provide them with essential nutrients lacking in their diet. We show that species harboring endosymbionts are indeed more likely to have a genetic system with male haploidy, which supports the hypothesis that endosymbionts might have played a role in the transition to haplodiploidy. We also extend our analysis to consider the relationship between endosymbiont presence and transitions to parthenogenesis. Although in scale insects there is no such overall association, species harboring eukaryote endosymbionts were more likely to be parthenogenetic than those with bacterial symbionts. These results support the idea that intergenomic conflict can drive the evolution of novel genetic systems and affect host reproduction.Peer reviewe

Parallel machine architecture and compiler design facilities

The objective is to provide an integrated simulation environment for studying and evaluating various issues in designing parallel systems, including machine architectures, parallelizing compiler techniques, and parallel algorithms. The status of Delta project (which objective is to provide a facility to allow rapid prototyping of parallelized compilers that can target toward different machine architectures) is summarized. Included are the surveys of the program manipulation tools developed, the environmental software supporting Delta, and the compiler research projects in which Delta has played a role

CMB anisotropy from spatial correlations of clusters of galaxies

The SZ effect from clusters of galaxies is a dominant source of secondary CMB anisotropy in the low-redshift universe. We present analytic predictions for the CMB power spectrum from massive halos arising from the SZ effect. Since halos are discrete, the power spectrum consists of a Poisson and a correlation term. The latter is always smaller than the former, which is dominated by nearby bright rich clusters. In practice however, those bright clusters are easy to indentify and can thus be subtracted from the map. After this subtraction, the correlation term dominates degree-scale fluctuations over the Poisson term, as the main contribution to the correlation term comes from distant clusters. We find that the correlation term is detectable by Planck experiment. Since the degree scale spectrum is quite insensitive to the highly uncertain core structures of halos, our predictions are robust on these scales. Measuring the correlation term on degree scales thus cleanly probes the clustering of distant halos. This has not been measured yet, mainly because optical and X-ray surveys are not sufficiently sensitive to include such distant clusters and groups. Our analytic predictions are also compared to adiabatic hydrodynamic simulations. The agreement is remarkably good, down to ten arcminutes scales, indicating that our predictions are robust for the Planck experiment. Below ten arcminute scales, where the details of the core structure dominates the power spectrum, our analytic and simulated predictions might fail. In the near future, interferometer and bolometer array experiments will measure the SZ power spectrum down to arcminutes scales, and yield new insight into the physics of the intrahalo medium.Comment: 9 pages, 4 figures. submitted to Proceedings of the 9th Marcel Grossmann meetin

Evaluating railway track support stiffness from trackside measurements in the absence of wheel load data

It is generally accepted that track support stiffness is a major factor controlling rates of track geometry deterioration, particularly where the track support stiffness changes abruptly. There is, therefore, considerable potential benefit in being able to quantify and detect changes in the track support stiffness. In recent years, trackside techniques using various types of transducer have been developed to determine track deflections as trains pass. However, deducing the track support stiffness from these measurements requires assumptions to be made concerning train loading and track behaviour, and scope for different interpretations remains. For example, loads from moving trains vary dynamically and it is not usually feasible to measure their exact values at any given point along the track. This paper presents new methods of analysis, which can be applied to frequency spectra of track displacement, velocity or acceleration generated as trains pass to calculate the track support stiffness for trains of known axle intervals, without needing to know the actual loads applied. The approach is demonstrated with reference to theory and measured data from a range of field sites

RE@CT - Immersive Production and Delivery of Interactive 3D Content

International audienceThis paper describes the aims and concepts of the FP7 RE@CT project. Building upon the latest advances in 3D capture and free-viewpoint video RE@CT aims to revolutionise the production of realistic characters and significantly reduce costs by developing an automated process to extract and represent animated characters from actor performance capture in a multiple camera studio. The key innovation is the development of methods for analysis and representation of 3D video to allow reuse for real-time interactive animation. This will enable efficient authoring of interactive characters with video quality appearance and motion

Sex Ratios under Asymmetrical Local Mate Competition: Theory and a Test with Parasitoid Wasps

International audienceOnline enhancement: appendix. abstract: Sex ratio theory allows unparalleled opportunities for testing how well animal behavior can be predicted by evolutionary theory. For example, Hamilton's theory of local mate competition (LMC) is well understood and can explain variation in sex allocation across numerous species. This allows more specific predictions to be developed and tested. Here we extend LMC theory to a situation that will be common in a range of species: asymmetrical LMC. Asymmetrical LMC occurs when females lay eggs on a patch asynchro-nously and male offspring do not disperse, leading to relatively weaker LMC for males emerging from later broods. Varying levels of LMC then lead to varying optimal sex ratios for females, depending on when and where they oviposit. We confirm the assumptions of our theory using the wasp Nasonia vitripennis and then test our predictions. We show that females adjust their offspring sex ratios in the directions predicted, laying different sex ratios on different hosts within a patch. Specifically, there was a less female-biased sex ratio when ovipositing on an unparasitized host if another host on the patch had previously been parasitized and a less female-biased sex ratio on parasitized hosts if females also oviposited on an un-parasitized host

Proving MEMS technologies for smarter railway infrastructure

Quantifying how railway track responds to passing trains in terms of displacement, velocity or acceleration, can provide insights into both the performance and the condition of the track. A number of trackside monitoring technologies have been shown to be capable of providing this information; however these are primarily research tools and tend to be costly hence actual deployments are relatively limited in scope. To assess systematically the changing health of railway track, more cost-effective continuous approaches to monitoring are required. Micro electrical mechanical systems (MEMS) are commonplace sensors in consumer electronics, low cost and can be used to measure acceleration. Thus they have the potential to provide the kind of data required to assess railway track behaviour at a much lower cost and in an environmentally robust small deployment package. However confidence in the quality of the data is required. This paper discusses the criteria for the selection of MEMS devices for this application. Laboratory trials and direct comparison of trackside measurements with well-established monitoring techniques demonstrate the effectiveness of the selected MEMS devices, and show their potential for use in continuous monitoring schemes to evaluate changes in track performance. The paper thus provides evidence that these kinds of low cost technologies are suitable for railway applications, building confidence in their use and enabling their adoption in self-monitoring smart infrastructure