Microscopic evidence for field-induced magnetism in CeCoIn5_5

We present NMR data in the normal and superconducting states of CeCoIn$_5$ for fields close to $H_{\rm c2}(0)=11.8$ T in the $ab$ plane. Recent experiments identified a first-order transition from the normal to superconducting state for $H> 10.5$ T, and a new thermodynamic phase below 290 mK within the superconducting state. We find that the Knight shifts of the In(1), In(2) and the Co are discontinuous across the first-order transition and the magnetic linewidths increase dramatically. The broadening differs for the three sites, unlike the expectation for an Abrikosov vortex lattice, and suggests the presence of static spin moments in the vortex cores. In the low-temperature and high-field phase the broad NMR lineshapes suggest ordered local moments, rather than a long wavelength quasiparticle spin density modulation expected for an FFLO phase.Comment: 4 pages, 4 figures. to appear in Phys. Rev. Let

75^{75}As NMR of Ba(Fe0.93_{0.93}Co0.07_{0.07})2_{2}As2_{2} in High Magnetic Field

The superconducting state of an optimally doped single crystal of Ba(Fe$_{0.93}$Co$_{0.07}$)$_2$As$_2$ was investigated by $^{75}$As NMR in high magnetic fields from 6.4 T to 28 T. It was found that the Knight shift is least affected by vortex supercurrents in high magnetic fields, $H>11$ T, revealing slow, possibly higher order than linear, increase with temperature at $T \lesssim 0.5 \, T_c$, with $T_c \approx 23 \, K$. This is consistent with the extended s-wave state with $A_{1g}$ symmetry but the precise details of the gap structure are harder to resolve. Measurements of the NMR spin-spin relaxation time, $T_2$, indicate a strong indirect exchange interaction at all temperatures. Below the superconducting transition temperature vortex dynamics lead to an anomalous dip in $T_2$ at the vortex freezing transition from which we obtain the vortex phase diagram up to $H = 28$ T.Comment: 13 pages, 9 figure

Interface characteristics in an {\alpha}+{\beta} titanium alloy

The alpha/beta interface in Ti-6Al-2Sn-4Zr-6Mo (Ti-6246) is investigated via centre of symmetry analysis, both as-grown and after 10% cold work. Semi-coherent interface steps are observed at a spacing of 4.5 +/-1.13 atoms in the as-grown condition, in good agreement with theory prediction (4.37 atoms). Lattice accommodation is observed, with elongation along [-1 2 -1 0]alpha and contraction along [1 0 -1 0]alpha . Deformed alpha exhibited larger, less coherent steps with slip bands lying in {110}beta. This indicates dislocation pile-up at the grain boundary, a precursor to globularisation, offering insight into the effect of deformation processing on the interface, which is important for titanium alloy processing route design.Comment: Revised after revie

Anomalous Attenuation of Transverse Sound in 3He

We present the first measurements of the attenuation of transverse sound in superfluid 3He-B. We use fixed path length interferometry combined with the magneto-acoustic Faraday effect to vary the effective path length by a factor of two, resulting in absolute values of the attenuation. We find that attenuation is significantly larger than expected from the theoretical dispersion relation, in contrast to the phase velocity of transverse sound. We suggest that the anomalous attenuation can be explained by surface Andreev bound states.Comment: 4 pages, 5 figures, accepted to Phys. Rev. Let

The hydraulic jump as a white hole

In the geometry of the circular hydraulic jump, the velocity of the liquid in the interior region exceeds the speed of capillary-gravity waves (ripplons), whose spectrum is `relativistic' in the shallow water limit. The velocity flow is radial and outward, and thus the relativistic ripplons cannot propagating into the interior region. In terms of the effective 2+1 dimensional Painleve-Gullstrand metric appropriate for the propagating ripplons, the interior region imitates the white hole. The hydraulic jump represents the physical singularity at the white-hole horizon. The instability of the vacuum in the ergoregion inside the circular hydraulic jump and its observation in recent experiments on superfluid 4He by E. Rolley, C. Guthmann, M.S. Pettersen and C. Chevallier in physics/0508200 are discussed.Comment: 10 pages, no figures, references added, version submitted to JETP Letter

Alien Species in the Flora of the Middle Volga Region

The article presents information on the diversity and structure of the alien flora of the Middle Volga region on the border between the steppe and forest-steppe zones of the European botanical and geographical province. In the studied area, we identified 440 alien species of plants (24.6% of the total floristic diversity), including 59 invasive and potentially invasive species, the dispersal of which has already caused environmental consequences or could become a threat in the future. According to the degree of naturalization, alien plant species among the regional flora are represented by 146 ephemerophytes (33.2%), 122 colonophytes (27.7%), 151 epecophytes (34.3%) and 21 agriophytes (4.8%). As verified via the main method of skidding, alien species are distributed almost equally – 228 xenophytes (51.8%) and 212 ergasiophygophytes (48.2%). It was revealed that of the 150 species of alien plants, there are only 84 of the most common European species in the Middle Volga region, most of which do not show high cenotic activity. The obtained results actualize the development of a system of ecological and economic assessment of the consequences of introducing alien plant species into regional flora. Keywords: alien plants, invasive species, Middle Volga region, regional flor

Structure and Metal Binding Properties of ZnuA, a Periplasmic Zinc Transporter from \u3cem\u3eEscherichia coli\u3c/em\u3e

ZnuA is the periplasmic Zn2+-binding protein associated with the high-affinity ATP-binding cassette ZnuABC transporter from Escherichia coli. Although several structures of ZnuA and its homologs have been determined, details regarding metal ion stoichiometry, affinity, and specificity as well as the mechanism of metal uptake and transfer remain unclear. The crystal structures of E. coli ZnuA (Eco-ZnuA) in the apo, Zn2+-bound, and Co2+-bound forms have been determined. ZnZnuA binds at least two metal ions. The first, observed previously in other structures, is coordinated tetrahedrally by Glu59, His60, His143, and His207. Replacement of Zn2+ with Co2+ results in almost identical coordination geometry at this site. The second metal binding site involves His224 and several yet to be identified residues from the His-rich loop that is unique to Zn2+ periplasmic metal binding receptors. Electron paramagnetic resonance and X-ray absorption spectroscopic data on CoZnuA provide additional insight into possible residues involved in this second site. The second site is also detected by metal analysis and circular dichroism (CD) titrations. Eco-ZnuA binds Zn2+ (estimated K d \u3c 20 nM), Co2+, Ni2+, Cu2+, Cu+, and Cd2+, but not Mn2+. Finally, conformational changes upon metal binding observed in the crystal structures together with fluorescence and CD data indicate that only Zn2+ substantially stabilizes ZnuA and might facilitate recognition of ZnuB and subsequent metal transfer

Elitologia da educação e desafios do século XXI

The object of this research is the elitology of education which represents a new character and a new meaning of elite selection according to the principle of high-quality professional knowledge. The article analyzes the key categories, approaches and directions, as well as the problems of changing attitudes towards elites and the elite in the context of the upcoming information society. In turn, the subject of this work is the challenges that the education system will have to face in the conditions of early post-industrial society. In the content of the work, the authors substantiate that the challenges of the 21st century will lead to a change not only in the system of elite (qualitative) training of specialists but also affect the very study of elites, making it more humanitarian. Nanotechnologies, the development of which has now become particularly accelerated and relevant should play a special role in this process.El objetivo de esta investigación es la elitología de la educación, que representa un nuevo carácter y un nuevo significado de la selección de élite de acuerdo con el principio de conocimiento profesional de alta calidad. El artículo analiza las categorías clave, los enfoques y las direcciones, así como los problemas de cambiar las actitudes hacia las elites y la élite en el contexto de la próxima sociedad de la información. A su vez, el tema de este trabajo son los desafíos que el sistema educativo tendrá que enfrentar en las condiciones de la sociedad postindustrial temprana. En el contenido del trabajo, los autores corroboran que los desafíos del siglo XXI conducirán a un cambio no solo en el sistema de entrenamiento de élite (cualitativo) de especialistas, sino que también afectarán el estudio mismo de las élites, haciéndolo más humanitario. Las nanotecnologías, cuyo desarrollo ahora se ha acelerado y es especialmente relevante, deben desempeñar un papel especial en este proceso.O objetivo desta pesquisa é a elitologia da educação, que representa um novo caráter e um novo significado de seleção de elite de acordo com o princípio do conhecimento profissional de alta qualidade. O artigo analisa as principais categorias, abordagens e direções, bem como os problemas de mudança de atitudes em relação às elites e à elite no contexto da próxima sociedade da informação. Por sua vez, o tema deste trabalho são os desafios que o sistema educacional terá que enfrentar nas condições da primeira sociedade pós-industrial. O conteúdo do trabalho, os autores confirmam que os desafios do século XXI vai levar a uma mudança não só no sistema de treinamento de elite especialistas (qualitativos), mas também afetam o mesmo estudo das elites, tornando-o mais humano. As nanotecnologias, cujo desenvolvimento agora se acelerou e é especialmente relevante, devem desempenhar um papel especial nesse processo

Manipulation and removal of defects in spontaneous optical patterns

Defects play an important role in a number of fields dealing with ordered structures. They are often described in terms of their topology, mutual interaction and their statistical characteristics. We demonstrate theoretically and experimentally the possibility of an active manipulation and removal of defects. We focus on the spontaneous formation of two-dimensional spatial structures in a nonlinear optical system, a liquid crystal light valve under single optical feedback. With increasing distance from threshold, the spontaneously formed hexagonal pattern becomes disordered and contains several defects. A scheme based on Fourier filtering allows us to remove defects and to restore spatial order. Starting without control, the controlled area is progressively expanded, such that defects are swept out of the active area.Comment: 4 pages, 4 figure

The Compact Group of Galaxies HCG 31 is in an early phase of merging

We have obtained high spectral resolution (R = 45900) Fabry-Perot velocity maps of the Hickson Compact Group HCG 31 in order to revisit the important problem of the merger nature of the central object A+C and to derive the internal kinematics of the candidate tidal dwarf galaxies in this group. Our main findings are: (1) double kinematic components are present throughout the main body of A+C, which strongly suggests that this complex is an ongoing merger (2) regions $A2$ and E, to the east and south of complex A+C, present rotation patterns with velocity amplitudes of $\sim 25 km s^{-1}$ and they counterrotate with respect to A+C, (3) region F, which was previously thought to be the best example of a tidal dwarf galaxy in HCG 31, presents no rotation and negligible internal velocity dispersion, as is also the case for region $A1$. HCG 31 presents an undergoing merger in its center (A+C) and it is likely that it has suffered additional perturbations due to interactions with the nearby galaxies B, G and Q.Comment: 5 pages + figures - Accepted to ApJ Lette