The Auroral Planetary Imaging and Spectroscopy (APIS) service

The Auroral Planetary Imaging and Spectroscopy (APIS) service, accessible online, provides an open and interactive access to processed auroral observations of the outer planets and their satellites. Such observations are of interest for a wide community at the interface between planetology and magnetospheric and heliospheric physics. APIS consists of (i) a high level database, built from planetary auroral observations acquired by the Hubble Space Telescope (HST) since 1997 with its mostly used Far-UltraViolet spectro-imagers, (ii) a dedicated search interface aimed at browsing efficiently this database through relevant conditional search criteria and (iii) the ability to interactively work with the data online through plotting tools developed by the Virtual Observatory (VO) community, such as Aladin and Specview. This service is VO compliant and can therefore also been queried by external search tools of the VO community. The diversity of available data and the capability to sort them out by relevant physical criteria shall in particular facilitate statistical studies, on long-term scales and/or multi-instrumental multi-spectral combined analysis

Hydrogen bonding as a clustering agent in protic ionic liquids: like-charge vs opposite-charge dimer formation

The local structure of a series of homologous protic ionic liquids (PILs) is investigated using ab initio computations and ab initio-based molecular dynamics. The purpose of this work is to show that in PILs the network of hydrogen bonds may promote like-charge clustering between anionic species. We correlate the theoretical evidence of this possibility with viscosity experimental data. The homologous series of liquids is obtained by coupling choline with amino acid anions and varying the side chain. We find that the frictional properties of the liquids are clearly connected to the ability of the side chain to establish additional hydrogen bonds (other than the trivial cation–anion interaction). We also show that the large variation of bulk properties along the series of compounds can be explained by assuming that one of the sources of friction in the bulk liquid is the like-charge interaction between anions

Selection and Control of Individual Domain Walls in Nanowire Arrays via Asymmetric Depinning Fields

Artificially inscribed notches are often used to pin domain walls (DWs) in ferromagnetic nanowires. The process of selecting and moving the trapped DW in nanowire arrays is an important step for potential applications. The chirality of a DW leads to a pair of pinning positions at the inscribed notches, which can be modeled by a symmetric double well. The depinning field depends on the side of the well, the DW is trapped with respect to the applied field direction, and the DWs can also be transitioned between the two wells without depinning. We demonstrate how manipulating the double well improves the DW selectivity and control in wire arrays containing multiple DWs

Short time growth of a KPZ interface with flat initial conditions

The short time behavior of the 1+1 dimensional KPZ growth equation with a flat initial condition is obtained from the exact expressions of the moments of the partition function of a directed polymer with one endpoint free and the other fixed. From these expressions, the short time expansions of the lowest cumulants of the KPZ height field are exactly derived. The results for these two classes of cumulants are checked in high precision lattice numerical simulations. The short time limit considered here is relevant for the study of the interface growth in the large diffusivity/weak noise limit, and describes the universal crossover between the Edwards-Wilkinson and KPZ universality classes for an initially flat interface.Comment: 9 pages, 7 figure

Expression, purification, and characterization of recombinant basic fibroblast growth factor in pichia pastoris

Wounds in the mouth, occurring after oral surgery, take time to heal. No ointment can be added to help with the healing process because mouth saliva will constantly wash it away. In order to combat this problem, we propose engineering a normal flora microbe to grow at the site of injury and secrete a recombinant growth factor to promote healing of the damaged tissue. Our goal is to have the yeast Pichia pastoris produce human basic fibroblast growth factor (bFGF), which aids in cellular proliferation. P. pastoris is a good choice for this application because not only is it considered generally recognized as safe (GRAS) by the FDA, but it is a eukaryote that is able to perform posttranslational modifications and secrete large amounts of recombinant protein. Previous studies have shown that a strain of P. pastoris can be engineered to express bFGF from a methanol-sensitive promoter. The study also showed that the bFGF, which was purified from the yeast’s extracellular medium, was able to promote the growth of NIH/3T3 cells (mice fibroblasts). Because we needed the P. pastoris to express the bFGF in glucose –based tissue culture medium in the presence of mammalian cells, we expressed the bFGF from the constitutive promoter GAP promoter. Along with optimizing and characterizing expression of bFGF, we also investigated the effect of the recombinant protein on mammalian cell growth using both scratch ad MTS assays. In addition, the effects of the yeast being co-cultured with mammalian cells was studied. Our results provide a basis for how a recombinant protein can be clinically used to improve wound healing in the mouth using a yeast strain to produce and secrete a growth factor at the site of injury

Thermal regime of the NW shelf of the Gulf of Mexico. 1) Thermal and pressure fields

National audienceThe thermal field of the Gulf of Mexico (GoM) is analyzed from a comprehensive temperature-depth database of about 8500 Bottom Hole Temperatures and Reservoir Temperatures. Our stochastic analysis reveals a widespread, systematic sharp thermal gradient increase between 2500 and 4000 m. The analysis of the pressure regime indicates a systematic correlation between the pressure and temperature fields

Rise and fall of a multicomponent droplet in a surrounrdfing fluid: simulation study of a bumpy path

The coupling between mass transfer and hydrodynamic phenomena in two-phase flow is not necessarily straightforward due to the different effects that can be encountered. The treatment of such coupling is complex and requires particular efforts, especially in the modelling of the interface between phases. In this paper, we consider the case of a droplet composed of two components (one miscible and one immiscible in water) released in a 2D rectangular domain filled with water. Mass transfer occurs between the miscible element and the surrounding water, which leads to a density inversion that directly affects the droplet trajectory through buoyancy. We perform simulations using a ternary Cahn-Hilliard model (implemented in the "phase\_field" model of the TrioCFD code) to capture such coupled phenomena. The Boussinesq approximation for a multicomponent system is used to define the density law and an analytical chemical potential is proposed for the thermodynamic landscape. The effect of the mobility parameter on the flow is highlighted and the results found are in good agreement with the dynamics described from an experimental study of the open literature

Electromagnetic fields in compact binaries: a post-Newtonian approach

Galactic binaries, and notably double white dwarfs systems, will be a prominent source for the future LISA and Einstein Telescope detectors. Contrarily to the black holes observed by the current LIGO-Virgo-KAGRA network, such objects bear intense magnetic fields, that are naturally expected to leave some imprints on the gravitational wave emission. The purpose of this work is thus to study those imprints within the post-Newtonian (PN) framework, particularly adapted to double white dwarfs systems. To this end, we construct an effective action that takes into account the whole electromagnetic structure of a star, and then specify it to dipolar order. With this action at hand, we compute the acceleration and Noetherian quantities for generic electric and magnetic dipoles, at a relative 2PN order. Finally, focusing on physically relevant systems, we show that the magnetic effects on the orbital frequency, energy and angular momentum is significant, confirming previous works conclusions.Comment: 23 pages, no figure, supplementary material attached v2: references and acknowledgments update