Development of satisfactory lateral- directional handling qualities in the landing approach

Developing lateral stability and directional control handling qualities in landing approach control of aircraf

Pressure-induced superconductivity in the giant Rashba system BiTeI

At ambient pressure, BiTeI is the first material found to exhibit a giant Rashba splitting of the bulk electronic bands. At low pressures, BiTeI undergoes a transition from trivial insulator to topological insulator. At still higher pressures, two structural transitions are known to occur. We have carried out a series of electrical resistivity and AC magnetic susceptibility measurements on BiTeI at pressure up to ~40 GPa in an effort to characterize the properties of the high-pressure phases. A previous calculation found that the high-pressure orthorhombic P4/nmm structure BiTeI is a metal. We find that this structure is superconducting with Tc values as high as 6 K. AC magnetic susceptibility measurements support the bulk nature of the superconductivity. Using electronic structure and phonon calculations, we compute Tc and find that our data is consistent with phonon-mediated superconductivity.Comment: 7 pages, 7 figure

Defect formation in superconducting rings: external fields and finite-size effects

Consistent with the predictions of Kibble and Zurek, scaling behaviour has been seen in the production of fluxoids during temperature quenches of superconducting rings. However, deviations from the canonical behaviour arise because of finite-size effects and stray external fields. Technical developments, including laser heating and the use of long Josephson tunnel junctions, have improved the quality of data that can be obtained. With new experiments in mind we perform large-scale 3D simulations of quenches of small, thin rings of various geometries with fully dynamical electromagnetic fields, at nonzero externally applied magnetic flux. We find that the outcomes are, in practice, indistinguishable from those of much simpler Gaussian analytical approximations in which the rings are treated as one-dimensional systems and the magnetic field fluctuation-free.Comment: 10 pages, 3 figures, presentation at QFS2012, to appear in JLT

Searches for New Quarks and Leptons Produced in Z-Boson Decay

We have searched for events with new-particle topologies in 390 hadronic Z decays with the Mark II detector at the SLAC Linear Collider. We place 95%-confidence-level lower limits of 40.7 GeV/c^2 for the top-quark mass, 42.0 GeV/c^2 for the mass of a fourth-generation charge - 1/3 quark, and 41.3 GeV/c^2 for the mass of an unstable Dirac neutral lepton

Phase Transition in Strongly Degenerate Hydrogen Plasma

Direct fermionic path-integral Monte-Carlo simulations of strongly coupled hydrogen are presented. Our results show evidence for the hypothetical plasma phase transition. Its most remarkable manifestation is the appearance of metallic droplets which are predicted to be crucial for the electrical conductivity allowing to explain the rapid increase observed in recent shock compression measurments.Comment: 1 LaTeX file using jetpl.cls (included), 5 ps figures. Manuscript submitted to JETP Letter

Determination of Effective Permittivity and Permeability of Metamaterials from Reflection and Transmission Coefficients

We analyze the reflection and transmission coefficients calculated from transfer matrix simulations on finite lenghts of electromagnetic metamaterials, to determine the effective permittivity and permeability. We perform this analysis on structures composed of periodic arrangements of wires, split ring resonators (SRRs) and both wires and SRRs. We find the recovered frequency-dependent permittivity and permeability are entirely consistent with analytic expressions predicted by effective medium arguments. Of particular relevance are that a wire medium exhibits a frequency region in which the real part of permittivity is negative, and SRRs produce a frequency region in which the real part of permeability is negative. In the combination structure, at frequencies where both the recovered real part of permittivity and permeability are simultaneously negative, the real part of the index-of-refraction is found also to be unambigously negative.Comment: *.pdf file, 5 figure

The equivalence of four extensions of context-free grammars

There is currently considerable interest among computational linguists in grammatical formalisms with highly restricted generative power. This paper concerns the relationship between the class of string languages generated by several such formalisms, namely, combinatory categorial grammars, head grammars, linear indexed grammars, and tree adjoining grammars. Each of these formalisms is known to generate a larger class of languages than context-free grammars. The four formalisms under consideration were developed independently and appear superficially to be quite different from one another. The result presented in this paper is that all four of the formalisms under consideration generate exactly the same class of string languages

High pressure transport properties of the topological insulator Bi2Se3

We report x-ray diffraction, electrical resistivity, and magnetoresistance measurements on Bi2Se3 under high pressure and low temperature conditions. Pressure induces profound changes in both the room temperature value of the electrical resistivity as well as the temperature dependence of the resistivity. Initially, pressure drives Bi2Se3 towards increasingly insulating behavior and then, at higher pressures, the sample appears to enter a fully metallic state coincident with a change in the crystal structure. Within the low pressure phase, Bi2Se3 exhibits an unusual field dependence of the transverse magnetoresistance that is positive at low fields and becomes negative at higher fields. Our results demonstrate that pressures below 8 GPa provide a non-chemical means to controllably reduce the bulk conductivity of Bi2Se3

Gliadin antibody detection in gluten enteropathy

Circulating antigliadin antibody has been described in patients with gluten enteropathy although the prevalence varies in different studies. It has been suggested that the investigation for antigliadin antibody might be useful as a screening test. The object of the present study was to evaluate two different techniques for assaying these antibodies - an indirect immunofluorescent method and an enzyme-linked immunosorbent assay (ELISA). Antibodies were assayed in the sera of 102 patients in whom jejunal biopsies were also obtained. The specificity of both tests was greater than 95%, and the correlation between the presence of antibody and histology was significant (p <0.005), though the sensitivity of each test was less than 70%

Rural men and mental health: their experiences and how they managed

There is a growing awareness that a primary source of information about mental health lies with the consumers. This article reports on a study that interviewed rural men with the aim of exploring their mental health experiences within a rural environment. The results of the interviews are a number of stories of resilience and survival that highlight not only the importance of exploring the individuals' perspective of their issues, but also of acknowledging and drawing on their inner strengths. Rural men face a number of challenges that not only increase the risk of mental illness but also decrease the likelihood of them seeking and/or finding professional support. These men's stories, while different from each other, have a common thread of coping. Despite some support from family and friends participants also acknowledged that seeking out professional support could have made the recovery phase easier. Mental health nurses need to be aware, not only of the barrier to professional support but also of the significant resilience that individuals have and how it can be utilised