Superfluidity versus Anderson localization in a dilute Bose gas

in Physical Review Letters (2007), 98(21),

We consider the motion of a quasi-one-dimensional beam of Bose-Einstein condensed particles in a disordered region of finite extent. Interaction effects lead to the appearance of two distinct regions of ... [more ▼]

We consider the motion of a quasi-one-dimensional beam of Bose-Einstein condensed particles in a disordered region of finite extent. Interaction effects lead to the appearance of two distinct regions of stationary flow. One is subsonic and corresponds to superfluid motion. The other one is supersonic and dissipative and shows Anderson localization. We compute analytically the interaction-dependent localization length. We also explain the disappearance of the supersonic stationary flow for large disordered samples. [less ▲]

The supergiant Bep star CD - 42 11721 deg and its surrounding nebula

in Astronomy and Astrophysics (1990), 238

New spectroscopic and direct imagery observations of the supergiant Bep star CD - 42 11721 deg and its surrounding nebula are reported. The spectrum of the star essentially consists of Balmer and Fe II ... [more ▼]

New spectroscopic and direct imagery observations of the supergiant Bep star CD - 42 11721 deg and its surrounding nebula are reported. The spectrum of the star essentially consists of Balmer and Fe II emission lines, He I emission lines are also observed, confirming the presence of spectral variations on long timescales. The clumpy arc-shaped structure of the nebula as well as the presence of motions relative to the central star highly suggest that it has been influenced by a variable mass-loss. The nebula shows both the reflection and emission characteristics. Its spectrum displays the red forbidden N II and S II lines while no oxygen forbidden lines can be detected. Its tempting to interpret this situation by a N/O overabundance which may indicate the presence of processed material in the nebula and thus confirm the evolved nature of the star. [less ▲]

Superhydrophobic surfaces by electrospinning of polymer mixtures

Poster (2008, May 22)

Hydrophobic surfaces have found great interest in environment resist coating, antifouling marine structures and low friction devices whereas superhydrophobic materials, with contact angle higher than 150° ... [more ▼]

Hydrophobic surfaces have found great interest in environment resist coating, antifouling marine structures and low friction devices whereas superhydrophobic materials, with contact angle higher than 150°, are of special interest in self-cleaning surfaces and stain resistant textiles. (Super)hydrophobicity is a key property that depends on both the surface chemistry and surface roughness. Numerous methods were reported for the preparation of superhydrophobic surfaces by either increasing the surface roughness of an inherently hydrophobic material or decreasing the surface free energy of a rough surface by post-treatment. For instance, controlled crystallization, lithography , etching were reported in the literature for the production of such surfaces. Nevertheless, all these techniques suffer from some drawback such as high cost, time consuming and expensive processes. As an alternative approach, electrospinning was proposed for the production of superhydrophobic surfaces with controlled roughness, morphology and/or porosity. For instance, Acatay et Al. reported on the preparation of electrospun fibers starting from a poly(AN-co-TMI)/fluorolink-D mixture followed by the annealing of these material in order to enable the reorientation of the perfluorinated groups to the solid-air interface. Rutledge et al. described the preparation of superhydrophobic surfaces by combining electrospinning of PCL and initiated chemical vapor deposition of perfluoroalkyl ethyl methacrylate. Allcock et al. prepared superhydrophibic nanofibers by electrospinning of an organic-soluble poly[bis(2,2,2-trifluoroethoxy)phosphazene]. In order to simplify the experimental protocols described in the literature on the preparation of superhydrophobic surfaces and decrease the cost related to the use of pure fluoropolymers, electrospinning of homopolymer/semifluorinated diblock copolymer mixture, i.e. a polyisobornylacrylate/poly(isobornyl acrylate-b-heptadecafluorodecyl acrylate) mixture, onto aluminum plates is proposed in this study. In practice, a diblock copolymer based on 1H,1H,2H,2H heptadecafluorodecyl acrylate and isobornyl acrylate was prepared by RAFT polymerization. In a second step, electrospinning of PIBA/PAC8-b-PIBA mixtures of different compositions was investigated. At high fluorine content ([PIBA]/[PAC8-b-PIBA] = 50/50), the electrospun mats show high surface roughness (microparticles of undefined morphologies) and a superhydrophic character. By decreasing the fluorine content, the morphology of the films changed from particles to beaded fibers (([PIBA]/[PAC8-b-PIBA] = 70/30) or fibers (([PIBA]/[PAC8-b-PIBA] = 85/15), which is consistent with an increase of the solution viscosity, but the surfaces still demonstrate or tend to superhydrophobicity. [less ▲]

Superinfection prevents recombination of the alphaherpesvirus bovine herpesvirus 1

in Journal of Virology (2004), 78(8), 3872-3879

Homologous recombination between strains of the same alphaherpesvirus species occurs frequently both in vitro and in vivo. This process has been described between strains of herpes simplex virus type 1 ... [more ▼]

Homologous recombination between strains of the same alphaherpesvirus species occurs frequently both in vitro and in vivo. This process has been described between strains of herpes simplex virus type 1, herpes simplex virus type 2, pseudorabies virus, feline herpesvirus 1, varicella-zoster virus, and bovine herpesvirus 1 (BoHV-1). In vivo, the rise of recombinant viruses can be modulated by different factors, such as the dose of the inoculated viruses, the distance between inoculation sites, the time interval between inoculation of the first and the second virus, and the genes in which the mutations are located. The effect of the time interval between infections with two distinguishable BoHV-1 on recombination was studied in three ways: (i) recombination at the level of progeny viruses, (ii) interference induced by the first virus infection on beta-gallactosidase gene expression of a superinfecting virus, and (iii) recombination at the level of concatemeric DNA. A time interval of 2 to 8 h between two successive infections allows the establishment of a barrier, which reduces or prevents any successful superinfection needed to generate recombinant viruses. The dramatic effect of the time interval on the rise of recombinant viruses is particularly important for the risk assessment of recombination between glycoprotein E-negative marker vaccine and field strains that could threaten BoHV-1 control and eradication programs. [less ▲]

Superiority of blue (470 nm) light in eliciting non-image forming brain responses during auditory working memory in humans: a fMRI study

in Journal of Sleep Research (2006, September), 15(Suppl. 1), 54

Superiority of blue (470nm) light in eliciting non-image forming brain responses during auditory working memory in humans : a fMRI study

Conference (2006)

Superlative Scaffold of 1,2,4-Triazole Derivative of Glycine Steering Linear Chain to a Chiral Helicate

in Crystal Growth & Design (2011), 11

Supernumerary outer hair cells arise external to the last row of sensory cells in the neonatal organ of Corti

Conference (2000)

Supernumerary outer hair cells arise external to the last row of sensory cells in the organ of corti.

in Acta Oto-Laryngologica (2001), 121(2), 164-8

During the development of the mammalian inner ear, the number of hair cells produced is highly regulated and remains constant throughout life. The mechanism underlying this regulation is beginning to be ... [more ▼]

During the development of the mammalian inner ear, the number of hair cells produced is highly regulated and remains constant throughout life. The mechanism underlying this regulation is beginning to be understood although many aspects still remain obscure. When late embryonic or early postnatal rat organs of Corti were cultured, the production of supernumerary hair cells was observed. This overproduction of sensory cells could be modulated by the addition of several growth factors. In this study, we examined explants of rat organs of Corti that produced supernumerary hair cells. In the supernumerary hair cell region, up to two rows of inner hair cells and five rows of outer hair cells were observed. Morphological evaluation of these specimens revealed that less mature hair cells were located in the most external rows of these sensory cells. When a supernumerary hair cell was produced, a supporting cell (i.e. Deiters' cell) was also produced, strongly suggesting that the conversion of a Deiters' cell into a hair cell was not the mechanism that produced these extra hair cells. Based on these results, we propose that prosensory cells located at the external edge of the organ of Corti retain a capacity to form hair cells and that it is these prosensory cells that differentiate into supernumerary hair cells and Deiters' cells. [less ▲]

Superovulation in the mare with commercially available pFSH

in Reproduction in Domestic Animals (2011), 46(s3), 138

Further studies on Stimufol with larger numbers, should be conducted as it might prove inexpensive and easy to superovulate mares.