Assessment of RNAi-induced silencing in banana (Musa spp.)

In plants, RNA- based gene silencing mediated by small RNAs functions at the transcriptional or post-transcriptional level to negatively regulate target genes, repetitive sequences, viral RNAs and/or transposon elements. Post-transcriptional gene silencing (PTGS) or the RNA interference (RNAi) approach has been achieved in a wide range of plant species for inhibiting the expression of target genes by generating double-stranded RNA (dsRNA). However, to our knowledge, successful RNAi-application to knock-down endogenous genes has not been reported in the important staple food crop banana

The star-forming complex LMC-N79 as a future rival to 30 Doradus

Within the early Universe, `extreme' star formation may have been the norm rather than the exception. Super Star Clusters (SSCs; $M_\star$ $\gtrsim$ 10$^5$ M$_\odot$) are thought to be the modern-day analogs of globular clusters, relics of a cosmic time ($z$ $\gtrsim$ 2) when the Universe was filled with vigorously star-forming systems. The giant HII region 30 Doradus in the Large Magellanic Cloud (LMC) is often regarded as a benchmark for studies of extreme star formation. Here, we report the discovery of a massive embedded star forming complex spanning $\sim$ 500 pc in the unexplored southwest region of the LMC, which manifests itself as a younger, embedded twin of 30 Doradus. Previously known as N79, this region has a star formation efficiency exceeding that of 30 Doradus by a factor of $\sim$ 2 as measured over the past $\lesssim$ 0.5 Myr. Moreover, at the heart of N79 lies the most luminous infrared (IR) compact source discovered with large-scale IR surveys of the LMC and Milky Way, possibly a precursor to the central SSC of 30 Doradus, R136. The discovery of a nearby candidate SSC may provide invaluable information to understand how extreme star formation proceeds in the current and high-redshift Universe.Comment: Nature Astronomy, published online 2nd of October 201

OVI, NV and CIV in the Galactic Halo: II. Velocity-Resolved Observations with Hubble and FUSE

We present a survey of NV and OVI (and where available CIV) in the Galactic halo, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope (HST) along 34 sightlines. These ions are usually produced in nonequilibrium processes such as shocks, evaporative interfaces, or rapidly cooling gas, and thus trace the dynamics of the interstellar medium. Searching for global trends in integrated and velocity-resolved column density ratios, we find large variations in most measures, with some evidence for a systematic trend of higher ionization (lower NV/OVI column density ratio) at larger positive line-of-sight velocities. The slopes of log[N(NV)/N(OVI)] per unit velocity range from -0.015 to +0.005, with a mean of -0.0032+/-0.0022(r)+/-0.0014(sys) dex/(km/s). We compare this dataset with models of velocity-resolved high-ion signatures of several common physical structures. The dispersion of the ratios, OVI/NV/CIV, supports the growing belief that no single model can account for hot halo gas, and in fact some models predict much stronger trends than are observed. It is important to understand the signatures of different physical structures to interpret specific lines of sight and future global surveys.Comment: ApJ in press 43 pages, 22 fig

Impact of three-dimensional standing waves on a flat horizontal plate

International audienceA set-up is designed in order to study the wave impact on structures. These structures can be the stern part of cruiser, a fixed structure as a pier or the roof of LNG-tank. The traveling waves impact was already studied by Smith et al. (1998) but it seems difficult to elaborate a model except some empirical formulæ linking the drop height, the wavelength and the wave steepness. Barrholm (2001) as well studied the travelling wave impact underneath decks of platforms. His modelling is based on a two-dimensional Wagner model where the determination of the wetted surface is not a simple task. Here a simplified impact phenomenon is investigated since standing waves are generated

Hydrodynamic modeling of partial dikes

International audienceDue to lack of space, the city of Monaco has extended over the sea, by land reclaiming. The bordering waterdepths are now so deep that the city has been considering building housings set on jacket types of struc tures. These constructions would have to be protected from sea waves, by so-called "partial dikes". An example of such partial dikes is the BYBOP caisson that was installed recently at the mouth of Port Hercule. Its shape was optimized through systematic model tests. Quite noticeable are the slanted parts that protrude both on the up-wave and down-wave sides. The appendix on the lee-side was found to have quite a strong effect on the reduction of the transmission coeffcient

Fragmentation Instability of Molecular Clouds: Numerical Simulations

We simulate fragmentation and gravitational collapse of cold, magnetized molecular clouds. We explore the nonlinear development of an instability mediated by ambipolar diffusion, in which the collapse rate is intermediate to fast gravitational collapse and slow quasistatic collapse. Initially uniform stable clouds fragment into elongated clumps with masses largely determined by the cloud temperature, but substantially larger than the thermal Jeans mass. The clumps are asymmetric, with significant rotation and vorticity, and lose magnetic flux as they collapse. The clump shapes, intermediate collapse rates, and infall profiles may help explain observations not easily fit by contemporary slow or rapid collapse models.Comment: 25pp, 20 small eps figures, in press ApJ, April 1, 200

HCI and environmental public policy:opportunities for engagement

This note discusses opportunities for the HCI community to engage with environmental public policy. It draws on insights and observations made during the primary author’s recent work for a policy unit at Global Affairs Canada, which is a federal ministry of the Government of Canada. During that work, the primary author identified several domains of environmental public policy that are of direct relevance to the HCI commu- nity. This note contributes a preliminary discussion of how, why, with whom, and in what capacity HCI researchers and practitioners might engage with three types of environmental public policy: climate change, waste electrical and electronic equipment, and green ICT procurement policies. This builds on existing public policy and environmental knowledge within the HCI community and responds directly to calls from some members to engage with environmental public policy