166 research outputs found
LâHistoire de la peinture en Italie : un sanctuaire pour lâheureux petit nombre
In the Histoire de la peinture en Italie (1817), Stendhal does not describe the paintings. He depreciates the formal aspect of the art of painting because he assigns to it a symbolic fonction : painting is constructed spirituality. To speak about painting is to educate the readerâs sensibility in order for him to create a bond of sympathy with the soul of the artist and of his figures. Painting becomes a sanctuary. To keep away the non believers, Stendhal elaborates a encrypted writing intended for the happy few
Precipitate stability and recrystallisation in the weld nuggets of friction stir welded Al-Mg-Si and Al-Mg-Sc alloys
Two different precipitate hardening aluminium alloys processed by friction
stir welding were investigated. The microstructure and the hardness of the as
delivered materials were compared to that of the weld nugget. Transmission
electron microscopy observations combined with three-dimensional atom probe
analyses clearly show that \beta;" precipitates dissolved in the nugget of the
Al-Mg-Si giving rise to some supersaturated solid solution. It is shown that
the dramatic softening of the weld could be partly recovered by post-welding
ageing treatments. In the Al-Mg-Sc alloy, Al3Sc precipitate size and density
are unchanged in the nugget comparing to the base metal. These precipitates
strongly reduce the boundary mobility of recrystallised grains, leading to a
grain size in the nugget much smaller than in the Al-Mg-Si alloy. Both coherent
and incoherent precipitates were detected. This feature may indicate that a
combination of continuous and discontinuous recrystallisation occurred in the
weld nugget
Isolation and sequence analysis of the wheat B genome subtelomeric DNA
<p>Abstract</p> <p>Background</p> <p>Telomeric and subtelomeric regions are essential for genome stability and regular chromosome replication. In this work, we have characterized the wheat BAC (bacterial artificial chromosome) clones containing Spelt1 and Spelt52 sequences, which belong to the subtelomeric repeats of the B/G genomes of wheats and <it>Aegilops </it>species from the section <it>Sitopsis</it>.</p> <p>Results</p> <p>The BAC library from <it>Triticum aestivum </it>cv. Renan was screened using Spelt1 and Spelt52 as probes. Nine positive clones were isolated; of them, clone 2050O8 was localized mainly to the distal parts of wheat chromosomes by <it>in situ </it>hybridization. The distribution of the other clones indicated the presence of different types of repetitive sequences in BACs. Use of different approaches allowed us to prove that seven of the nine isolated clones belonged to the subtelomeric chromosomal regions. Clone 2050O8 was sequenced and its sequence of 119 737 bp was annotated. It is composed of 33% transposable elements (TEs), 8.2% Spelt52 (namely, the subfamily Spelt52.2) and five non-TE-related genes. DNA transposons are predominant, making up 24.6% of the entire BAC clone, whereas retroelements account for 8.4% of the clone length. The full-length CACTA transposon <it>Caspar </it>covers 11 666 bp, encoding a transposase and CTG-2 proteins, and this transposon accounts for 40% of the DNA transposons. The <it>in situ </it>hybridization data for 2050O8 derived subclones in combination with the BLAST search against wheat mapped ESTs (expressed sequence tags) suggest that clone 2050O8 is located in the terminal bin 4BL-10 (0.95-1.0). Additionally, four of the predicted 2050O8 genes showed significant homology to four putative orthologous rice genes in the distal part of rice chromosome 3S and confirm the synteny to wheat 4BL.</p> <p>Conclusion</p> <p>Satellite DNA sequences from the subtelomeric regions of diploid wheat progenitor can be used for selecting the BAC clones from the corresponding regions of hexaploid wheat chromosomes. It has been demonstrated for the first time that Spelt52 sequences were involved in the evolution of terminal regions of common wheat chromosomes. Our research provides new insights into the microcollinearity in the terminal regions of wheat chromosomes 4BL and rice chromosome 3S.</p
The impact of Ty3-gypsy group LTR retrotransposons Fatima on B-genome specificity of polyploid wheats
<p>Abstract</p> <p>Background</p> <p>Transposable elements (TEs) are a rapidly evolving fraction of the eukaryotic genomes and the main contributors to genome plasticity and divergence. Recently, occupation of the A- and D-genomes of allopolyploid wheat by specific TE families was demonstrated. Here, we investigated the impact of the well-represented family of <it>gypsy </it>LTR-retrotransposons, <it>Fatima</it>, on B-genome divergence of allopolyploid wheat using the fluorescent <it>in situ </it>hybridisation (FISH) method and phylogenetic analysis.</p> <p>Results</p> <p>FISH analysis of a BAC clone (BAC_2383A24) initially screened with Spelt1 repeats demonstrated its predominant localisation to chromosomes of the B-genome and its putative diploid progenitor <it>Aegilops speltoides </it>in hexaploid (genomic formula, BBAADD) and tetraploid (genomic formula, BBAA) wheats as well as their diploid progenitors. Analysis of the complete BAC_2383A24 nucleotide sequence (113 605 bp) demonstrated that it contains 55.6% TEs, 0.9% subtelomeric tandem repeats (Spelt1), and five genes. LTR retrotransposons are predominant, representing 50.7% of the total nucleotide sequence. Three elements of the <it>gypsy </it>LTR retrotransposon family <it>Fatima </it>make up 47.2% of all the LTR retrotransposons in this BAC. <it>In situ </it>hybridisation of the <it>Fatima</it>_2383A24-3 subclone suggests that individual representatives of the <it>Fatima </it>family contribute to the majority of the B-genome specific FISH pattern for BAC_2383A24. Phylogenetic analysis of various <it>Fatima </it>elements available from databases in combination with the data on their insertion dates demonstrated that the <it>Fatima </it>elements fall into several groups. One of these groups, containing <it>Fatima</it>_2383A24-3, is more specific to the B-genome and proliferated around 0.5-2.5 MYA, prior to allopolyploid wheat formation.</p> <p>Conclusion</p> <p>The B-genome specificity of the <it>gypsy</it>-like <it>Fatima</it>, as determined by FISH, is explained to a great degree by the appearance of a genome-specific element within this family for <it>Ae. speltoides</it>. Moreover, its proliferation mainly occurred in this diploid species before it entered into allopolyploidy.</p> <p>Most likely, this scenario of emergence and proliferation of the genome-specific variants of retroelements, mainly in the diploid species, is characteristic of the evolution of all three genomes of hexaploid wheat.</p
Trends of labile trace metals in tropical urban water under highly contrasted weather conditions
International audienceThe spatio-temporal trend of trace metals (Cd, Co, Cr, Cu, Ni, Pb, and Zn) in a tropical urban estuary under the influence of monsoon was determined using diffusive gradient in thin films (DGT) in situ samplers. Three different climatic periods were observed: period 1, dry with dredging activity; period 2, intermediate meaning from dry to wet event; and period 3, wet having continuous rainfall. Conforming to monsoon regimes, these periods correspond to the following: transition from winter to summer, winter, and summer monsoons, respectively. The distinction of each period is defined by their specific hydrological and physico-chemical conditions. Substantial concentrations of the trace metals were detected. The distribution and trend of the trace metals under the challenge of a tropical climate were able to follow using DGT as a sensitive in situ sampler. In order to identify the differences among periods, statistical analyses were performed. This allowed discriminating period 2 (oxic water) as significantly different compared to other periods. The spatio-temporal analysis was then applied in order to distinguish the trend of the trace metals. Results showed that the trend of trace metals can be described according to their response to (i) seasonal variations (Cd and Cr), (ii) spatio-temporal conditions (Co, Cu, Ni, and Pb), and (iii) neither (i) nor (ii) meaning exhibiting no response or having constant change (Zn). The correlation of the trace metals and the physico-chemical parameters reveals that Cd, Co, Cu, and Cr are proportional to the dissolved oxygen (DO), Cd and Ni are correlated pH, and Zn lightly influenced by salinity
Distribution of trace elements in waters and sediments of the Seversky Donets transboundary watershed (Kharkiv region, Eastern Ukraine)
International audienceThis paper reports on the aquatic chemistry of trace elements in terms of spatial and temporal distribution, but also pollution sources in the transboundary watershed of the Seversky Donets River (Ukraine/Russia). Bed sediments and filtered water were collected from the Udy and Lopan Rivers at sites from the river source in the Belgorod region (Russia) to rural and urban areas in the Kharkiv region (Ukraine) in May and August 2009. Priority trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn), an urban tracer (Ag) and additional metals (Co, Mo, V) and Th were measured in stream water and sediments. The low levels and variability of Th-normalized concentrations indicated the absence of geochemical anomalies in the upstream part of the rivers and suggested that these data represent a regional baseline for trace elements in bed sediments. In contrast, water and sediments within the city of Kharkiv were contaminated by Ag, Pb, Cd, Cu, Cr and Zn, which are mainly attributed to municipal wastewater inputs and urban run-off. Results of the environmental quality assessment showed that element concentrations in the sediments can be considered as potentially toxic to aquatic organisms in sites downstream of the wastewater discharges
Husbandry factors and health conditions influencing the productivity of French rabbit farms
[EN] In 2009 productivity data from 95 kindling to finishing rabbit farms in France were analysed to identify rearing factors and health conditions that influenced their productivity. Farm productivity, expressed on a yearly basis, was described with 4 productivity indices: doe fertility and prolificacy, viability of young rabbits in the nest and mortality during the fattening period. The productivity data were obtained with the technical support of the farm and expressed in a standardised way. The average numerical productivity observed in the sample of farms was 50.9 rabbits produced per doe and per year (CI95% [49.6-52.2]). The husbandry management and health conditions were described based on a questionnaire filled out during an interview with the farmer and a farm visit. Explanatory data were organised into meaningful blocks relative to biosecurity measures, del using a Partiamaternity management, the sanitary context and the farm structure. The relationship between the 4 thematic blocks and the productivity indices was studied in a single mol Least Squares (PLS) regression model. Fertility (81.0%, CI95% [80.0-82.0]) and viability of young at nest (85.1%, CI95% [85.0-85.3] and mortality rate during fattening: 7.2%, CI95% [6.4-7.9]) were significantly associated with common factors relative to maternity management and the health context whereas prolificacy (9.7 live kits per parturition, CI95% [9.5-9.9]) was mostly influenced by a specific set of variables pertaining to those 2 blocks. Farm structure and biosecurity measures had a limited impact on fertility and on kit viability before weaning. The health conditions of the doe herd and the fattening rabbits were found to be significantly associated with several productivity indexes, but their impacts on productivity were as high as the impact of the other blocks. Genetic strain of the females, doe replacement strategy and nursing and weaning practices appeared to significantly influence reproductive performance, viability of kits before weaning and mortality rate during the fattening period. Maternity management therefore seemed to be the key point in rabbit unit management that governed the numerical productivity of the farm.The authors wish to acknowledge the CLIPP-Lapin de France, the SNGTV (French Veterinary Society - rabbit
branch) and the FFC (French Federation of Cuniculture) for their collaboration. We also wish to thank the farmers and the rabbit
production organisations who participated in the study. The authors are grateful to Ms. AnaĂŻs Croisier for her participation as an
investigator and to Mr. Guillaume Coutelet from the French Institute for Avian Production for his technical expertise. Funding was
provided by the French Agency for Veterinary Medicinal Products (ANSES-ANMV)Huneau-SalaĂŒn, A.; Bougeard, S.; Balaine, L.; Eono, F.; Le Bouquin, S.; Chauvin, C. (2015). Husbandry factors and health conditions influencing the productivity of French rabbit farms. World Rabbit Science. 23(1):27-37. https://doi.org/10.4995/wrs.2015.3076SWORD2737231Castellini, C., Dal Bosco, A., Arias-Ălvarez, M., Lorenzo, P. L., Cardinali, R., & Rebollar, P. G. (2010). The main factors affecting the reproductive performance of rabbit does: A review. Animal Reproduction Science, 122(3-4), 174-182. doi:10.1016/j.anireprosci.2010.10.003Coutelet G. 2011. Performances moyennes des Ă©levages cunicoles en France pour l'annĂ©e 2010. Cuniculture Magazine, 38: 24-27.EFSA. 2005. Scientific Opinion of the Scientific Panel on Animal Health and Welfare on the impact of the current housing and husbandry systems on the health and welfare of farmed domestic rabbits. EFSA J., 2005: 1-31.Lebas F. 2010. Situation cunicole en France en 2009: performances moyennes des Ă©levages selon les rĂ©sultats du RENACEB pour l'annĂ©e 2009, situation du marchĂ© cunicole français et premiĂšres Ă©valuations pour l'annĂ©e 2010. Cuniculture Magazine, 37: 74-82.Licois D., Coudert P., Marlier D. 2006. Epizootic rabbit enteropathy. In: L. Maertens, P. Coudert (ed). Recent advances in rabbit sciences. Institute for Agricultural and Fisheries Research, Melle, Belgium, 163-170.Marongiu M.L., Dimauro C., Floris B. 2007. A six-year investigation on reproductive performance of hybrid rabbits. 1. Pregnancy rate and numerical productivity at weaning as affected by season. Ital. J. Anim. Sci., 6: 770-772.Rommers J., Maertens L., Kemp B. 2006. New perspectives in rearing systems for rabbit does. In: L. Maertens, P. Coudert (ed). Recent advances in rabbit sciences. Institute for Agricultural and Fisheries Research, Melle, Belgium, 39-51.Serrano P., Pascual M., GĂłmez E.A. 2012. Analysis of management techniques on productivity indicators using the bdcuni Spanish database. In Proc.: 10th World Rabbit Congress, 3-6 September, 2012. Sharm El-Sheikh, Egypt. 1: 803-807
An unusual carbon cycle budget of a small stream in a mountain silicate terrain: The case of the Gravona river (Corsica)
Abstract
The current research of carbon cycling in inland waters lacks a sound knowledge of carbon outgassing from small streams. As a consequence, these compartments of the terrestrial water cycle might still be seriously underrepresented in estimates of global carbon transfer budgets from land surfaces. This study investigated carbon sources and sinks of a mountain river in a silicate catchment. For this purpose, the highârelief Gravona river, in the western part of the island of Corsica (France) in the Western Mediterranean, was investigated for field parameters, dissolved inorganic carbon (DIC) and its stable carbon isotopes (ÎŽ13CDIC). The source region was characterized by low DIC contents and high ÎŽ13CDIC values that decreased further downstream due to increasing soil respiration. Associated increasing DIC concentrations and elevated seasonality in the lower river section also indicated more respiration and subsequent DICâinput by weathering. The aqueous partial pressure (pCO2(aq)) was lowest at the source of the Gravona river and samples from the cold season even showed undersaturation that led to uptake of atmospheric CO2. Further downstream, the seasonality of pCO2(aq) increased and was particularly pronounced near the river mouth where CO2 degassing took place. Average DIC flux along the river was 0.129âGgâCâyearâ1 and was almost equal to CO2 degassing from the river surface with 0.128âGgâCâyearâ1. Our study showed that on an annual basis the river is an overall weak to medium source of CO2 to the atmosphere even though headwater parts of the river seasonally act as CO2 sinks
Recommended from our members
Past millennium hydroclimate variability from Corsican pine tree-ring chronologies
Palaeoclimatic evidence is necessary to place the current warming and drying trends of the Mediterranean region in a longâterm perspective of preâindustrial variability. Annually resolved and absolutely dated climate proxies that extend back into medieval times are, however, limited to a few sites only. Here we present a network of long ring width chronologies from Pinus nigra treeâline sites in northern Corsica (France) that cohere exceptionally well over centuries and support the development of a single highâelevation pine chronology extending back to 974 CE. We apply various detrending methods to these data to retain highâtoâlow frequency ring width variability and scale the resulting chronologies against instrumental precipitation and drought observations to produce hydroclimate reconstructions for the last millennium. Proxy calibration and transfer are challenged by a lack of highâelevation meteorological data, however, limiting our understanding of precipitation changes in subâalpine treeâline environments. Our new reconstructions extend beyond existing records and provide evidence for lowâfrequency precipitation variability in the centralâwestern Mediterranean from 974â2016 CE. Comparison with a European scale drought reconstruction network shows that regional predictor chronologies are needed to accurately estimate longâterm hydroclimate variability on Corsica
Tritium as a hydrological tracer in Mediterranean precipitation events
Climate models are in need of improved constraints for water vapor transport in the atmosphere, and tritium can serve as a powerful tracer in the hydrological cycle. Although the general principles of tritium distribution and transfer processes within and between the various hydrological compartments are known, variation on short timescales and aspects of altitude dependence are still under debate. To address questions regarding tritium sources, sinks, and transfer processes, the sampling of individual precipitation events in Corte on the island of Corsica in the Mediterranean Sea was performed between April 2017 and April 2018. Tritium concentrations of 46 event samples were compared to their moisture origin and corresponding air mass history. Air mass back-trajectories were generated from the novel high-resolution ERA5 dataset from the ECMWF (European Centre for Medium-Range Weather Forecasts). Geographical source regions with similar tritium concentrations were predefined using generally known tritium distribution patterns, such as the âcontinental effectâ, and from data records derived at long-term measurement stations of tritium in precipitation across the working area. Our model-derived source region tritium concentrations agreed well with annual mean station values. Moisture that originated from continental Europe and the Atlantic Ocean was most distinct regarding tritium concentrations with values up to 8.8âTU (tritium units) and near 0âTU, respectively. The seasonality of tritium values ranged from 1.6âTU in January to 10.1âTU in May, and they exhibited well-known elevated concentrations in spring and early summer due to increased stratosphereâtroposphere exchange. However, this pattern was interrupted by extreme events. The average altitude of trajectories was correlated with the tritium concentrations in precipitation, especially in spring and early summer and if outlier values of extreme tritium concentrations were excluded. However, in combination with the trajectory information, these outlier values proved to be valuable for improving the comprehension of tritium movement in the atmosphere. Our work shows how event-based tritium research can advance the understanding of its distribution in the atmosphere
- âŠ