Transcription, signaling receptor activity, oxidative phosphorylation, and fatty acid metabolism mediate the presence of closely related species in distinct intertidal and cold-seep habitats

Bathyal cold seeps are isolated extreme deep-sea environments characterized by low species diversity while biomass can be high. The Hakon Mosby mud volcano (Barents Sea, 1,280 m) is a rather stable chemosynthetic driven habitat characterized by prominent surface bacterial mats with high sulfide concentrations and low oxygen levels. Here, the nematode Halomonhystera hermesithrives in high abundances (11,000 individuals 10 cm(-2)). Halomonhystera hermesi is a member of the intertidal Halomonhystera disjuncta species complex that includes five cryptic species (GD 1-5). GD1-5's common habitat is characterized by strong environmental fluctuations. Here, we compared the transcriptomes of H. hermesi and GD1, H. hermesi's closest relative. Genes encoding proteins involved in oxidative phosphorylation are more strongly expressed in H. hermesi than in GD1, and many genes were only observed in H. hermesi while being completely absent in GD1. Both observations could in part be attributed to high sulfide concentrations and low oxygen levels. Additionally, fatty acid elongation was also prominent in H. hermesi confirming the importance of highly unsaturated fatty acids in this species. Significant higher amounts of transcription factors and genes involved in signaling receptor activity were observed in GD1 (many of which were completely absent in H. hermesi), allowing fast signaling and transcriptional reprogramming which can mediate survival in dynamic intertidal environments. GC content was approximately 8% higher in H. hermesi coding unigenes resulting in differential codon usage between both species and a higher proportion of amino acids with GC-rich codons in H. hermesi. In general our results showed that most pathways were active in both environments and that only three genes are under natural selection. This indicates that also plasticity should be taken in consideration in the evolutionary history of Halomonhystera species. Such plasticity, as well as possible preadaptation to low oxygen and high sulfide levels might have played an important role in the establishment of a cold-seep Halomonhystera population

A unified approach to solve ill-posed inverse problems in econometrics

We consider the general issue of estimating a nonparametric function x from the inverse problem r = Tx given estimates of the function r and of the linear transform T. Two typical examples include the estimation of a probability density function fromdata contaminated by a noise whose distribution is unknown (blind deconvolution) and the nonparametric instrumental regression. We provide a unified framework based on Hilbert scales that synthesizes most of existing results in the econometric literature and also covers new relevant structural models. Results are given on the rate of convergence of the estimator of x as well as of its derivatives.inverse problem, Hilbert scale, deconvolution, instrumental variable, nonparametric regression

The aid of TRNSYS simulation for the conservation of an artwork: a case study

Due to secularization more and more churches lose their original function, that is a place to worship, and become a place of cultural interest. To fulfil the comfort demands, a heating system or a HVAC-system was installed. These systems however impose new boundary conditions for the interior objects like paintings,. which may lead to damage. The case of the Saint-Bavo Cathedral in Ghent, Belgium is presented in this paper. In this church hangs the valuable polyptic 'The adoration of the mystic Lamb' painted by van Eyck. Use was made of a computer simulation to get insight in the working of different solutions to combine comfort and preservation. Because we want to be able in first instance to evaluate a whole year, a BES-software, was used. Using the dynamic simulation code TRNSYS the system performance in controlling thermal-hygrometric ambient parameters were obtained