HST Observations of the QSO pair Q1026-0045A,B

The spatial distribution of the Ly$\alpha$ forest is studied using new HST data for the quasar pair Q~1026--0045 A and B at $z_{em}$ = 1.438 and 1.520 respectively. The angular separation is 36 arcsec and corresponds to transverse linear separations between lines of sight of $\sim300h^{-1}_{50}$ kpc ($q_{o}$ = 0.5) over the redshift range 0.833 < z < 1.438. From the observed numbers of coincident and anti-coincident Ly$\alpha$ absorption lines, we conclude that, at this redshift, the Ly$\alpha$ structures have typical dimensions of $\sim500h^{-1}_{50}$ kpc, larger than the mean separation of the two lines of sight. The velocity difference, $\Delta V$, between coincident lines is surprisingly small (4 and 8 pairs with $\Delta V < 50 and 200 km/s respectively). Metal line systems are present at$z_{abs}$= 1.2651 and 1.2969 in A,$z_{abs}$= 0.6320, 0.7090, 1.2651 and 1.4844 in B. In addition we tentatively identify a weak Mg II system at$z_{abs}$= 0.11 in B. It is remarkable that the$z_{abs}$= 1.2651 system is common to both lines of sight. The system at$z_{abs}$= 1.4844 There is a metal-poor associated system at$z_{abs}$= 1.4420 along the line of sight to A with complex velocity profile. We detect a strong Ly$\alpha$absorption along the line of sight to B redshifted by only 300 km/s relatively to the associated system. It is tempting to interpret this as the presence of a disk of radius larger than 300$h^{-1}_{50}$ kpc surrounding quasar A.Comment: 4 pages, 2 figures, A&A Letter acccepte

Supervised Gaze Bias Correction for Gaze Coding in Interactions

Understanding the role of gaze in conversations and social interactions or exploiting it for HRI applications is an ongoing research subject. In these contexts, vision based eye trackers are preferred as they are non-invasive and allow people to behave more naturally. In particular, appearance based methods (ABM) are very promising, as they can perform online gaze estima- tion and have the potential to be head pose and person invariant, accommodate more situations as well as user mobility and the resulting low resolution images. However, they may also suffer from a lack of robustness when several of these challenges are jointly present. In this work, we address gaze coding in human-human interactions, and present a simple method based on a few manually annotated frames that is able to much reduce the error of a head pose invariant ABM method, as shown on a dataset of 6 interactions

Towards the Use of Social Interaction Conventions as Prior for Gaze Model Adaptation

Gaze is an important non-verbal cue involved in many facets of social interactions like communication, attentiveness or attitudes. Nevertheless, extracting gaze directions visually and remotely usually suffers large errors because of low resolution images, inaccurate eye cropping, or large eye shape variations across the population, amongst others. This paper hypothesizes that these challenges can be addressed by exploiting multimodal social cues for gaze model adaptation on top of an head-pose independent 3D gaze estimation framework. First, a robust eye cropping refinement is achieved by combining a semantic face model with eye landmark detections. Investigations on whether temporal smoothing can overcome instantaneous refinement limitations is conducted. Secondly, to study whether social interaction convention could be used as priors for adaptation, we exploited the speaking status and head pose constraints to derive soft gaze labels and infer person-specific gaze bias using robust statistics. Experimental results on gaze coding in natural interactions from two different settings demonstrate that the two steps of our gaze adaptation method contribute to reduce gaze errors by a large margin over the baseline and can be generalized to several identities in challenging scenarios

Perception des effets de l’aménagement de la salle d’apprentissage actif sur les interactions pédagogiques

Cet article présente les résultats d’une étude exploratoire des effets des espaces d’apprentissage actif sur la relation étudiant-enseignant et étudiant-étudiant en particulier en termes d’interactions et de changement de posture. À partir d’une démarche mixte combinant un questionnaire étudiant et des entretiens enseignant, nous partagerons les résultats d’une première étude appelée à se renouveler pour rendre davantage compte des effets des salles d’apprentissage actif sur le rôle de l’enseignant et les apprentissages des étudiants. Notre étude portant sur deux espaces d’apprentissage actif a été menée auprès de 7 enseignants et 467 étudiants dans une école d’ingénieur. Les résultats présentés dans cet article démontrent que l’aménagement et la configuration de la salle d’apprentissage actif&nbsp;: 1) ne transforment pas les activités pédagogiques mais les soutiennent et facilitent leur mise en place 2) enseignant et étudiant changent de posture et de rôle pour une relation basée sur l’accompagnement et la collaboration

Cationic siRNAs Provide Carrier-Free Gene Silencing in Animal Cells

siRNA-mediated gene silencing requires intracellular delivery of the nucleic acid. We have developed a carrierless molecular approach that follows the same cell entry route as cationic supramolecular complexes, yet should avoid the extracellular barriers encountered by nanoparticles. Cationic oligospermine−oligonucleotide conjugates (ZNAs, for Zip Nucleic Acids) were synthesized stepwise on an oligonucleotide synthesizer using a DMT-spermine phosphoramidite derivative. They were shown to enter cells and have access to the cytoplasm, provided their formal charge ratio N/P was >1.5. Cationic siRNAs that fulfilled this condition were shown to achieve selective inhibition of luciferase gene expression in the submicromolar concentration range in constitutively luciferase-expressing cells

Induction of the HSP70 gene promoter by various anticancer drugs

International audienceHeLa cells containing the chloramphenicol acetyl transferase (CAT) gene under the control of the hsp70 promoter have been exposed in vitro to various anticancer drugs. Cisplatin induced CAT production with a dose-effect relationship at a non-cytotoxic dose, whereas no induction was detected with carboplatin. Etoposid induced a significant response at a cytotoxic concentration. The limited positive response with doxorubicin, daunomycin and mitoxantrone was not statistically significant. These chemicals are known to produce reactive oxygen species and induce apoptosis. No induction of the hsp70 promoter could be detected with the other cytostatic compounds that have been tested such as base analogues (5-fluorouracil, cytosine arabinoside 3'-MP), inhibitors of DNA synthesis (amethopterin, aminopterin), antimitotics (vinblastine, colchicine), and alkylating (streptozotocine, carboplatin, melphalan) or intercalating agents (bleomycin). In addition, the role of the transcription inhibitory activity of doxorubicin in this model is evidenced and the consequent question of the suitability of the reporter gene system is discussed. Our results suggest that specific genotoxic compounds are not able to induce the hsp70 promoter, and are in agreement with the concept that stimulation of HSP70 synthesis occurs through a biochemical process involving proteotoxicity

Polydiacetylenic nanofibers as new siRNA vehicles for in vitro and in vivo delivery

Polydiacetylenic nanofibers (PDA-Nfs) obtained by photopolymerization of surfactant 1 were optimized for intracellular delivery of small interfering RNAs (siRNAs). PDA-Nfs/siRNA complexes efficiently silenced the oncogene Lim-1 in the renal cancer cells 786-O in vitro. Intraperitoneal injection of PDA-Nfs/siLim1 downregulated Lim-1 in subcutaneous tumor xenografts obtained with 786-O cells in nude mice. Thus, PDA-Nfs represent an innovative system for in vivo delivery of siRNAs

The three pillars of natural product dereplication. Alkaloids from the bulbs of Urceolina peruviana (C. Presl) J.F. Macbr. as a preliminary test case

open access articleThe role and importance of the identification of natural products are first discussed in the perspective of the study of secondary metabolites. The rapid identification of already reported compounds, or structural dereplication, is recognized as a key element in natural product chemistry. The biological taxonomy of metabolite producing organisms, the knowledge of metabolite molecular structures, and the availability of metabolite spectroscopic signatures are considered as the three pillars of structural dereplication. The role and the construction of databases is illustrated by references to the KNApSAcK, UNPD, CSEARCH, and COCONUT databases, and by the importance of calculated taxonomic and spectroscopic data as substitutes for missing or lost original ones. Two NMR-based tools, the PNMRP database that derives from UNPD, and KnapsackSearch, a database generator that provides taxonomically focused libraries of compounds, are proposed to the community of natural product chemists. The study of the alkaloids from Urceolina peruviana, a plant from the Andes used in traditional medicine for antibacterial and anticancer actions, has given the opportunity to test different approaches to dereplication, favoring the use of publicly available data sources