Symbiont diversity is not involved in depth acclimation in the Mediterranean sea whip Eunicella singularis

In symbiotic cnidarians, acclimation to depth and lower irradiance can involve physiological changes in the photosynthetic dinoflagellate endosymbiont, such as increased chlorophyll content, or qualitative modifications in the symbiont population in favour of better adapted strains. It has been argued that a lack of capacity to acquire new symbionts could limit the bathymetric distribution of the host species, or compromise its long-term survival in a changing environment. But is that always true? To address this question, we investigated the symbiont genetic diversity in Eunicella singularis, a Mediterranean sea whip species with a wide bathymetric distribution (10 to 50 m depth), which has recently suffered from mass mortalities after periods of abnormally high sea temperatures. We measured symbiont population densities and chlorophyll content in natural populations, and followed the response of the holobionts after reciprocal transplantations to deep and shallow depths. A total of 161 colonies were sampled at 2 depths (10 and 30 m) at 5 sites in the northwestern Mediterranean. All colonies harboured a single ribosomal Symbiodinium clade (A'), but a relatively high within-clade genetic diversity was found among and within colonies. This diversity was not structured by depth, even though the deeper colonies contained significantly lower population densities of symbionts and less chlorophyll. We did, however, reveal host-symbiont specificity among E. singularis and other Mediterranean cnidarian species. Transplantation experiments revealed a limit of plasticity for symbiont population density and chlorophyll content, which in turn questions the importance of the trophic role of Symbiodinium in E. singularis

Control of Pre-mRNA Splicing by the General Splicing Factors PUF60 and U2AF65

Pre-mRNA splicing is a crucial step in gene expression, and accurate recognition of splice sites is an essential part of this process. Splice sites with weak matches to the consensus sequences are common, though it is not clear how such sites are efficiently utilized. Using an in vitro splicing-complementation approach, we identified PUF60 as a factor that promotes splicing of an intron with a weak 3' splice-site. PUF60 has homology to U2AF(65), a general splicing factor that facilitates 3' splice-site recognition at the early stages of spliceosome assembly. We demonstrate that PUF60 can functionally substitute for U2AF(65)in vitro, but splicing is strongly stimulated by the presence of both proteins. Reduction of either PUF60 or U2AF(65) in cells alters the splicing pattern of endogenous transcripts, consistent with the idea that regulation of PUF60 and U2AF(65) levels can dictate alternative splicing patterns. Our results indicate that recognition of 3' splice sites involves different U2AF-like molecules, and that modulation of these general splicing factors can have profound effects on splicing

Possible Superconductivity at 37 K in Graphite-Sulfur Composite

Sulfur intercalated graphite composites with diamagnetic transitions at 6.7 K and 37 K are prepared. The magnetization hysteresis loops (MHL), Xray diffraction patterns, and resistance were measured. From the MHL, a slight superconducting like penetration process is observed at 15 K in low field region. The XRD shows no big difference from the mixture of graphite and sulfur indicating that the volume of the superconducting phase (if any) is very small. The temperature dependence of resistance shows a typical semiconducting behavior with a saturation in low temperature region. This saturation is either induced by the de-localization of conducting electrons or by possible superconductivity in this system.Comment: CHIN. PHYS.LETT v18 1648 (2001

Towards improved socio-economic assessments of ocean acidification’s impacts

Ocean acidification is increasingly recognized as a component of global change that could have a wide range of impacts on marine organisms, the ecosystems they live in, and the goods and services they provide humankind. Assessment of these potential socio-economic impacts requires integrated efforts between biologists, chemists, oceanographers, economists and social scientists. But because ocean acidification is a new research area, significant knowledge gaps are preventing economists from estimating its welfare impacts. For instance, economic data on the impact of ocean acidification on significant markets such as fisheries, aquaculture and tourism are very limited (if not non-existent), and non-market valuation studies on this topic are not yet available. Our paper summarizes the current understanding of future OA impacts and sets out what further information is required for economists to assess socio-economic impacts of ocean acidification. Our aim is to provide clear directions for multidisciplinary collaborative research

Optimal Operation of the Multireservoir System in the Seine River Basin Using Deterministic and Ensemble Forecasts

International audienceThis article investigates the improvement of the operation of a four-reservoir system in the Seine River basin, France, by use of deterministic and ensemble weather forecasts and real-time control. In the current management, each reservoir is operated independently from the others and following prescribed rule-curves, designed to reduce floods and sustain low flows under the historical hydrological conditions. However, this management system is inefficient when inflows are significantly different from their seasonal average and may become even more inadequate to cope with the predicted increase in extreme events induced by climate change. In this work, a centralized real-time control system is developed to improve reservoirs operation by exploiting numerical weather forecasts that are becoming increasingly available. The proposed management system implements a well-established optimization technique, model predictive control (MPC), and its recently modified version that can incorporate uncertainties, tree-based model predictive control (TB-MPC), to account for deterministic and ensemble forecasts respectively. The management system is assessed by simulation over historical events and compared to the no-forecasts strategy based on rule-curves. Simulation results show that the proposed real-time control system largely outperforms the no-forecasts management strategy, and that explicitly considering forecast uncertainty through ensembles can compensate for the loss in performance due to forecast inaccuracy

Descobrindo “para-formalidades”: atividades que gritam por espaço

A pesquisa trabalha no sentido de mapear e dar visibilidade às cenas “para-formais” encontradas no espaço público dos centros de cidades latinoamericanas. Entendemos “para-formal” como todas as atividades encontradas no espaço público da cidade que não fazem parte de seu desenho urbano (original), mas que “agora” fazem parte de seu cotidiano. A investigação se dá a partir de cartografias urbanas, fazendo uso de recursos infográficos e sendo divulgado em tempo real por meio de website. Destacamos as principais “paraformalidades” encontradas na maioria das cidades que estudamos: trailers, para-ciclos inventados, para-formal no formal, vendedores isolados móveis e o grandes conjuntos para-formais. Podemos adiantar que é possível compreender que esses equipamentos são parte da cidade e devem ser levados em consideração pelos arquitetos e urbanistas, tanto em novos projetos como em revitalizações arquitetônicas e urbanísticas.The research works towards mapping and profiling the scenes “para-formal” found in the public space of the centers of Latin American cities. We understand “para-formal” as all activities found in the public space of the city that are not part of their urban design (the original), but that “now” part of their daily lives. The research starts from urban cartography, making use of infographics and resources being released in real time via the website. Highlight the main “to-tape” found in most cities we studied: trailers, for-cycles invented, paraformal in the formal, isolated mobile sallers and large ensembles para-formals. We anticipate that it is possible to understand that the equipment is part of the city and should be considered by architects and planners, both in new projects such as in architectural and urban revitalization.Eje 3: Derecho a la ciudad: mutaciones, recomposiciones, adaptaciones, reformulaciones.Facultad de Arquitectura y Urbanism

Descobrindo “para-formalidades”: atividades que gritam por espaço

A pesquisa trabalha no sentido de mapear e dar visibilidade às cenas “para-formais” encontradas no espaço público dos centros de cidades latinoamericanas. Entendemos “para-formal” como todas as atividades encontradas no espaço público da cidade que não fazem parte de seu desenho urbano (original), mas que “agora” fazem parte de seu cotidiano. A investigação se dá a partir de cartografias urbanas, fazendo uso de recursos infográficos e sendo divulgado em tempo real por meio de website. Destacamos as principais “paraformalidades” encontradas na maioria das cidades que estudamos: trailers, para-ciclos inventados, para-formal no formal, vendedores isolados móveis e o grandes conjuntos para-formais. Podemos adiantar que é possível compreender que esses equipamentos são parte da cidade e devem ser levados em consideração pelos arquitetos e urbanistas, tanto em novos projetos como em revitalizações arquitetônicas e urbanísticas.The research works towards mapping and profiling the scenes “para-formal” found in the public space of the centers of Latin American cities. We understand “para-formal” as all activities found in the public space of the city that are not part of their urban design (the original), but that “now” part of their daily lives. The research starts from urban cartography, making use of infographics and resources being released in real time via the website. Highlight the main “to-tape” found in most cities we studied: trailers, for-cycles invented, paraformal in the formal, isolated mobile sallers and large ensembles para-formals. We anticipate that it is possible to understand that the equipment is part of the city and should be considered by architects and planners, both in new projects such as in architectural and urban revitalization.Eje 3: Derecho a la ciudad: mutaciones, recomposiciones, adaptaciones, reformulaciones.Facultad de Arquitectura y Urbanism

Descobrindo “para-formalidades”: atividades que gritam por espaço

A pesquisa trabalha no sentido de mapear e dar visibilidade às cenas “para-formais” encontradas no espaço público dos centros de cidades latinoamericanas. Entendemos “para-formal” como todas as atividades encontradas no espaço público da cidade que não fazem parte de seu desenho urbano (original), mas que “agora” fazem parte de seu cotidiano. A investigação se dá a partir de cartografias urbanas, fazendo uso de recursos infográficos e sendo divulgado em tempo real por meio de website. Destacamos as principais “paraformalidades” encontradas na maioria das cidades que estudamos: trailers, para-ciclos inventados, para-formal no formal, vendedores isolados móveis e o grandes conjuntos para-formais. Podemos adiantar que é possível compreender que esses equipamentos são parte da cidade e devem ser levados em consideração pelos arquitetos e urbanistas, tanto em novos projetos como em revitalizações arquitetônicas e urbanísticas.The research works towards mapping and profiling the scenes “para-formal” found in the public space of the centers of Latin American cities. We understand “para-formal” as all activities found in the public space of the city that are not part of their urban design (the original), but that “now” part of their daily lives. The research starts from urban cartography, making use of infographics and resources being released in real time via the website. Highlight the main “to-tape” found in most cities we studied: trailers, for-cycles invented, paraformal in the formal, isolated mobile sallers and large ensembles para-formals. We anticipate that it is possible to understand that the equipment is part of the city and should be considered by architects and planners, both in new projects such as in architectural and urban revitalization.Eje 3: Derecho a la ciudad: mutaciones, recomposiciones, adaptaciones, reformulaciones.Facultad de Arquitectura y Urbanism

Induced Magnetic Ordering by Proton Irradiation in Graphite

We provide evidence that proton irradiation of energy 2.25 MeV on highly-oriented pyrolytic graphite samples triggers ferro- or ferrimagnetism. Measurements performed with a superconducting quantum interferometer device (SQUID) and magnetic force microscopy (MFM) reveal that the magnetic ordering is stable at room temperature.Comment: 3 Figure

Probing complex RNA structures by mechanical force

RNA secondary structures of increasing complexity are probed combining single molecule stretching experiments and stochastic unfolding/refolding simulations. We find that force-induced unfolding pathways cannot usually be interpretated by solely invoking successive openings of native helices. Indeed, typical force-extension responses of complex RNA molecules are largely shaped by stretching-induced, long-lived intermediates including non-native helices. This is first shown for a set of generic structural motifs found in larger RNA structures, and then for Escherichia coli's 1540-base long 16S ribosomal RNA, which exhibits a surprisingly well-structured and reproducible unfolding pathway under mechanical stretching. Using out-of-equilibrium stochastic simulations, we demonstrate that these experimental results reflect the slow relaxation of RNA structural rearrangements. Hence, micromanipulations of single RNA molecules probe both their native structures and long-lived intermediates, so-called "kinetic traps", thereby capturing -at the single molecular level- the hallmark of RNA folding/unfolding dynamics.Comment: 9 pages, 9 figure