4 research outputs found

    Unravelling migration connectivity reveals unsustainable hunting of the declining ortolan bunting

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    In France, illegal hunting of the endangered ortolan bunting Emberiza hortulana has been defended for the sake of tradition and gastronomy. Hunters argued that ortolan buntings trapped in southwest France originate from large and stable populations across the whole of Europe. Yet, the European Commission referred France to the Court of Justice of the European Union (EU) in December 2016 for infringements to legislation (IP/16/4213). To better assess the impact of hunting in France, we combined Pan-European data from archival light loggers, stable isotopes, and genetics to determine the migration strategy of the species across continents. Ortolan buntings migrating through France come from northern and western populations, which are small, fragmented and declining. Population viability modeling further revealed that harvesting in southwest France is far from sustainable and increases extinction risk. These results provide the sufficient scientific evidence for justifying the ban on ortolan harvesting in France.Peer reviewe

    Analysis of full-disc Ca II K spectroheliograms

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    International audienceContext. Studies of long-term solar activity and variability require knowledge of the past evolution of the solar surface magnetism. The archives of full-disc Ca II K observations that have been performed more or less regularly at various sites since 1892 can serve as an important source of such information. Aims. We derive the plage area evolution over the last 12 solar cycles by employing data from all Ca II K archives that are publicly available in digital form, including several as-yet-unexplored Ca II K archives. Methods. We analysed more than 290 000 full-disc Ca II K observations from 43 datasets spanning the period between 1892–2019. All images were consistently processed with an automatic procedure that performs the photometric calibration (if needed) and the limb-darkening compensation. The processing also accounts for artefacts affecting many of the images, including some very specific artefacts, such as bright arcs found in Kyoto and Yerkes data. Our employed methods have previously been tested and evaluated on synthetic data and found to be more accurate than other methods used in the literature to treat a subset of the data analysed here. Results. We produced a plage area time-series from each analysed dataset. We found that the differences between the plage areas derived from individual archives are mainly due to the differences in the central wavelength and the bandpass used to acquire the data at the various sites. We empirically cross-calibrated and combined the results obtained from each dataset to produce a composite series of plage areas. The ’backbone’ approach was used to bridge the series together. We have also shown that the selection of the backbone series has little effect on the final composite of the plage area. We quantified the uncertainty of determining the plage areas with our processing due to shifts in the central wavelength and found it to be less than 0.01 in fraction of the solar disc for the average conditions found on historical data. We also found the variable seeing conditions during the observations to slightly increase the plage areas during the activity maxima. Conclusions. We provide the most complete so far time series of plage areas based on corrected and calibrated historical and modern Ca II K images. Consistent plage areas are now available on 88% of all days from 1892 onwards and on 98% from 1907 onwards

    Pericentromeric Non-Coding DNA Transcription Is Associated with Niche Impairment in Patients with Ineffective or Partially Effective Multiple Myeloma Treatment

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    Mesenchymal stromal cells (MSC) ‘educated’ by tumor cells are an essential component of the multiple myeloma (MM) tumor microenvironment (TME) involved in tumor progression. Transcription of tandemly repeated (TR) non-coding DNA is often activated in many tumors and is required for tumor progression and cancer cells genome reorganization. The aim of the work was to study functional properties including the TR DNA transcription profile of MSC from the hematopoietic niche of treated MM patients. Healthy donors (HD) and patients after bortezomib-based treatment (with partial or complete response, PoCR, and non-responders, NR) were enrolled in the study. Their trephine biopsies were examined histologically to evaluate the hematopoietic niche. MSC cultures obtained from the biopsies were used for evaluation of the proliferation rate, osteogenic differentiation, presence of tumor MSC markers, resistance to bortezomib, and pericentromeric TR DNA transcription level. The MSC ‘education’ by multiple myeloma cells was mimicked in co-culture experiments with or without bortezomib. The TR DNA transcription profile was accessed. The histological examination revealed the persistence of the tumor microenvironment (especially of the vasculature) in treated patients. In co-culture experiments, MSC of bortezomib-treated patients were more resistant to bortezomib and protected cancer MM cells of the RPMI8226 cell line more effectively than HD-MSC did. The MSC obtained from PoCR and NR samples differed in their functional properties (proliferation capacity, osteogenic potential, and cancer-associated fibroblasts markers). Transcriptome analysis revealed activation of the TR transcription in cells of non-hematopoietic origin from NR patients’ bone marrow. The pericentromeric TR DNA of HS2/HS3 families was among the most upregulated in stromal MSC but not in cancer cells. The highest level of transcription was observed in NR-MSC. Transcription of HS2/HS3 was not detected in healthy donors MSC unless they were co-cultured with MM cancer cells and acquired cancer-associated phenotype. Treatment with TNFα downregulated HS2/HS3 transcription in MSC and upregulated in MM cells. Our results suggest that the hematopoietic niche retains the cancer-associated phenotype after treatment. Pericentromeric non-coding DNA transcription is associated with the MSC cancer-associated phenotype in patients with ineffective or partially effective multiple myeloma treatment
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