Mesure des coefficients de déplacement de fréquence du rubidium 87 plongé dans l'azote moléculaire (N2)

Le but poursuivi dans cette thèse est la mesure du déplacement de la fréquence hyperfine du Rubidium 87 plongé dans l'azote moléculaire (N₂) à différentes densités, autour d'une température T₀ de 60 °C. Les résultats sont représentés par un développement en série, jusqu’au second degré en (T-T₀).Nous donnons la valeur des coefficients de déplacement de fréquence, définis comme les coefficients de ce développement normalisés à la densité de N₂. Nous avons observé une non linéarité du déplacement de fréquence en fonction de la densité de N₂, que nous interprétons comme découlant d'une erreur systématique sur la densité. Cette interprétation s'appuie sur une évaluation théorique de la non linéarité, et nous conduit à donner au coefficient de pression la valeur de la pente à l'origine de la courbe du déplacement de fréquence en fonction de la densité…Québec Université Laval, Bibliothèque 201

F.A.R.O.G. FORUM, Vol. 5 No. 1

https://digitalcommons.library.umaine.edu/francoamericain_forum/1059/thumbnail.jp

The hydrophobic region of the Leishmania peroxin 14 : requirements for association with a glycosome mimetic membrane

This work was funded by operating grants from the Canadian Institutes of Health Research (CIHR) and a Natural Sciences Engineering Research Council of Canada (NSERC) Discovery grant [Fonds de recherche du Québec — Nature et technologies (FRQNT) Regroupement Stratégique grant to the Centre for Host-Parasite Interactions (A.J.)]. N.C. was supported by a doctoral research scholarship from FRQNT. E.B. was supported by a Banting postdoctoral fellowship from CIHR. This work was also supported in part by Wellcome Trust grants [086658 and 093228] to T.K.S. C.S. recognizes the financial support from the Natural Sciences and Engineering Research Council of Canada and a Canada Foundation for Innovation grant [16299].Protein import into the Leishmania glycosome requires docking of the cargo-loaded peroxin 5 (PEX5) receptor to the peroxin 14 (PEX14) bound to the glycosome surface. To examine the LdPEX14-membrane interaction, we purified L. donovani promastigote glycosomes and determined the phospholipid and fatty acid composition. These membranes contained predominately phosphatidylethanolamine, phosphatidylcholine, and phosphatidylglycerol (PG) modified primarily with C18 and C22 unsaturated fatty acid. Using large unilamellar vesicles (LUVs) with a lipid composition mimicking the glycosomal membrane in combination with sucrose density centrifugation and fluorescence-activated cell sorting technique, we established that the LdPEX14 membrane-binding activity was dependent on a predicted transmembrane helix found within residues 149-179. Monolayer experiments showed that the incorporation of PG and phospholipids with unsaturated fatty acids, which increase membrane fluidity and favor a liquid expanded phase, facilitated the penetration of LdPEX14 into biological membranes. Moreover, we demonstrated that the binding of LdPEX5 receptor or LdPEX5-PTS1 receptor-cargo complex was contingent on the presence of LdPEX14 at the surface of LUVs.PostprintPeer reviewe

Le Forum, Vol. 44 #4

https://digitalcommons.library.umaine.edu/francoamericain_forum/1106/thumbnail.jp

F.A.R.O.G. FORUM, Vol. 5 No. 8

https://digitalcommons.library.umaine.edu/francoamericain_forum/1064/thumbnail.jp

F.A.R.O.G. FORUM, Vol. 5 No. 4

https://digitalcommons.library.umaine.edu/francoamericain_forum/1062/thumbnail.jp

Stripes in cuprate superconductors: Excitations and dynamic dichotomy

We present a short account of the present experimental situation of stripes in cuprates followed by a review of our present understanding of their ground state and excited state properties. Collective modes, the dynamical structure factor, and the optical conductivity of stripes are computed using the time-dependent Gutzwiller approximation applied to realistic one band and three band Hubbard models, and are found to be in excellent agreement with experiment. On the other hand, experiments like angle-resolved photoemission and scanning tunneling microscopy show the coexistence of stripes at high energies with Fermi liquid quasiparticles at low energies. We show that a phenomenological model going beyond mean-field can reconcile this dynamic dichotomy.Comment: 20 pages, 14 figures. Review paper for a Special Issue of Physica C on "Stripes and Electronic Liquid Crystals in Strongly Correlated Systems

F.A.R.O.G. FORUM, Vol. 6 No. 4

https://digitalcommons.library.umaine.edu/francoamericain_forum/1065/thumbnail.jp

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe