186,412 research outputs found
Mr Louis Guillot, La Forterre : son agriculture
No full textBloch Marc. Mr Louis Guillot, La Forterre : son agriculture. In: Annales d'histoire économique et sociale. 4ᵉ année, N. 16, 1932. p. 428
Mr Louis Guillot, La Forterre : son agriculture
No full textBloch Marc. Mr Louis Guillot, La Forterre : son agriculture. In: Annales d'histoire économique et sociale. 4ᵉ année, N. 16, 1932. p. 428
The Distribution and Impact of Viral Lineages in Domains of Life
No full textInternational audienceLiving organisms can be conveniently classified into three domains, Archaea, Bacteria,and Eukarya (Woeseetal.,1990). The three domains are united by several features that support the common origin of life including the presence of ribosomes, double-stranded DNA genomes,a nearly universal genetic code,physical compartments (i.e.,membranes),and the ability to carry out metabolism and oxidation- reduction reactions.In comparison,other types of genetic material and particles (e.g.,viruses,plasmids,andotherselfish geneticelements)are often excluded from the definition of "life"(for opposing views see Raoult and Forterre,2008; Forterre,2011,2012a). However,they can still influence the evolution of cellular organisms, and in conjunction,establish complex life cycles
The Mre11 protein interacts with both Rad50 and the HerA bipolar helicase and is recruited to DNA following gamma irradiation in the archaeon Sulfolobus acidocaldarius
No full textBackground: The ubiquitous Rad50 and Mre11 proteins play a key role in many processes involved in the maintenance of genome integrity in Bacteria and Eucarya, but their function in the Archaea is presently unknown. We showed previously that in most hyperthermophilic archaea, rad50-mre11 genes are linked to nurA encoding both a single-strand endonuclease and a 5' to 3' exonuclease, and herA, encoding a bipolar DNA helicase which suggests the involvement of the four proteins in common molecular pathway(s). Since genetic tools for hyperthermophilic archaea are just emerging, we utilized immuno-detection approaches to get the first in vivo data on the role(s) of these proteins in the hyperthermophilic crenarchaeon Sulfolobus acidocaldarius. Results: We first showed that S. acidocaldarius can repair DNA damage induced by high doses of gamma rays, and we performed a time course analysis of the total levels and sub-cellular partitioning of Rad50, Mre11, HerA and NurA along with the RadA recombinase in both control and irradiated cells. We found that during the exponential phase, all proteins are synthesized and display constant levels, but that all of them exhibit a different sub-cellular partitioning. Following gamma irradiation, both Mre11 and RadA are immediately recruited to DNA and remain DNA-bound in the course of DNA repair. Furthermore, we show by immuno-precipitation assays that Rad50, Mre11 and the HerA helicase interact altogether. Conclusion: Our analyses strongly support that in Sulfolobus acidocaldarius, the Mre11 protein and the RadA recombinase might play an active role in the repair of DNA damage introduced by gamma rays and/or may act as DNA damage sensors. Moreover, our results demonstrate the functional interaction between Mre11, Rad50 and the HerA helicase and suggest that each protein play different roles when acting on its own or in association with its partners. This report provides the first in vivo evidence supporting the implication of the Mre11 protein in DNA repair processes in the Archaea and showing its interaction with both Rad50 and the HerA bipolar helicase. Further studies on the functional interactions between these proteins, the NurA nuclease and the RadA recombinase, will allow us to define their roles and mechanism of action.Peer reviewe
Initiation of granular surface flows in a narrow channel
No full text5 pages, 5 figures, to be published in Physics of FluidsWe experimentally investigate how a long granular pile confined in a narrow channel destabilizes when it is inclined above the angle of repose. A uniform flow then develops, which is localized at the free surface. It first accelerates before reaching a steady uniform regime. During this process, an apparent erosion is observed and the thickness of the flowing layer increases. We precisely study the evolution of the vertical velocity profile in this transient regime. The measurements are compared with the prediction of a visco-plastic model [P. Jop, Y. Forterre and O. Pouliquen, Nature 441, 727 (2006)
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
DNA binding, compaction and negative supercolining by the architectural protein Sso7d of Sulfolobus solfataricus.
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