Classification of Bipartite and Tripartite Qutrit Entanglement under SLOCC

We classify biqutrit and triqutrit pure states under stochastic local operations and classical communication. By investigating the right singular vector spaces of the coefficient matrices of the states, we obtain explicitly two equivalent classes of biqutrit states and twelve equivalent classes of triqutrit states respectively.Comment: 10 page

Modular differential equations for torus one-point functions

It is shown that in a rational conformal field theory every torus one-point function of a given highest weight state satisfies a modular differential equation. We derive and solve these differential equations explicitly for some Virasoro minimal models. In general, however, the resulting amplitudes do not seem to be expressible in terms of standard transcendental functions.Comment: 19 pages, LaTeX; reference adde

Investigating the impact of nicotine on executive functions using a novel virtual reality assessment

Aims Nicotine is known to enhance aspects of cognitive functioning in abstinent smokers but the effects on specific areas of executive functions, and in non-smokers are inconclusive. This may be due in part to the poor sensitivity of tests used to assess executive functions. This study used a new virtual reality assessment of executive functions known as JEF (the Jansari assessment of Executive Functions) to address this issue. Design 2x2 design manipulating group (smokers and never-smokers) and drug (nicotine [4mg for smokers; 2mg for never smokers] vs placebo gum). Setting School of Psychology; University of East LondonParticipants 72 participants (aged 18 to 54). 36 minimally-deprived (2 hr) smokers and 36 never-smokers.Measurements Components of executive function were measured using the virtual reality paradigm JEF, which assesses eight cognitive constructs simultaneously as well as providing an overall performance measure. Results Univariate ANOVAs revealed that nicotine improved overall JEF performance, time-based prospective memory and event-based prospective memory in smokers (p < 0.01) but not in never-smokers. Action-based prospective memory was enhanced in both groups (p < 0.01) and never-smokers out-performed smokers on selective thinking and adaptive thinking (p < 0.01). Conclusions. Overall executive functioning and prospective memory can be enhanced by nicotine gum in abstinent smokers. That smokers were only minimally deprived suggests that JEFis a sensitive measure of executive functioning and that prospective memory is particularly susceptible to disruption by abstinence

A Submillimetre Search for Cold Extended Debris Disks in the Beta Pictoris Moving Group

The Beta Pictoris Moving Group is a nearby stellar association of young (12Myr) co-moving stars including the classical debris disk star beta Pictoris. Due to their proximity and youth they are excellent targets when searching for submillimetre emission from cold, extended, dust components produced by collisions in Kuiper-Belt-like disks. They also allow an age independent study of debris disk properties as a function of other stellar parameters. We observed 7 infrared-excess stars in the Beta Pictoris Moving Group with the LABOCA bolometer array, operating at a central wavelength of 870 micron at the 12-m submillimetre telescope APEX. The main emission at these wavelengths comes from large, cold dust grains, which constitute the main part of the total dust mass, and hence, for an optically thin case, make better estimates on the total dust mass than earlier infrared observations. Fitting the spectral energy distribution with combined optical and infrared photometry gives information on the temperature and radial extent of the disk. From our sample, beta Pic, HD181327, and HD172555 were detected with at least 3-sigma certainty, while all others are below 2-sigma and considered non-detections. The image of beta Pic shows an offset flux density peak located near the south-west extension of the disk, similar to the one previously found by SCUBA at the JCMT. We present SED fits for detected sources and give an upper limit on the dust mass for undetected ones. We find a mean fractional dust luminosity f_dust=11x10^{-4} at t=12Myr, which together with recent data at 100Myr suggests an f_dust propto t^{-alpha} decline of the emitting dust, with alpha > 0.8.Comment: 11 pages, 3 figures, 3 tables; accepted for publication in Astronomy & Astrophysic

Endothelial dysfunction is associated with carotid plaque: a cross-sectional study from the population based Northern Manhattan Study

BACKGROUND: Impaired vascular function occurs early in atherogenesis. Brachial flow mediated dilatation (FMD) is a non-invasive measure of vascular function and may be an important marker of preclinical atherosclerosis. Data on the association between FMD and carotid plaque in multi-ethnic populations are limited. The objective of this study was to determine whether endothelial dysfunction is independently associated with carotid plaque in a community of northern Manhattan. METHODS: In the population-based Northern Manhattan Study (NOMAS), high-resolution B-mode ultrasound images of the brachial and carotid arteries were obtained in 643 stroke-free subjects (mean age 66 years; 55% women; 65% Caribbean-Hispanic, 17% African-American, 16% Caucasian). Brachial FMD was measured during reactive hyperemia. Maximum carotid plaque thickness (MCPT) was measured at the peak plaque prominence. RESULTS: The mean brachial FMD was 5.78 ± 3.83 %. Carotid plaque was present in 339 (53%) subjects. The mean MCPT was 1.68 ± 0.82 mm, and the 75(th )percentile was 2.0 mm. Reduced FMD was significantly associated with increased MCPT. After adjusting for demographics, vascular risk factors, and education, each percent of FMD decrease was associated with a significant 0.02 mm increase in MCPT (p = 0.028). In a dichotomous adjusted model, blunted FMD was associated with an increased risk of MCPT ≥ 2.0 mm (OR, 1.11 for every 1% decrease in FMD; 95% CI, 1.03–1.19). CONCLUSION: Decreased brachial FMD is independently associated with carotid plaque. Non-invasive evaluation of endothelial dysfunction may be a useful marker of preclinical atherosclerosis and help to individualize cardiovascular risk assessment beyond traditional risk factors

A liquid crystalline copper phthalocyanine derivative for high performance organic thin film transistors

This journal is © The Royal Society of Chemistry 2012Bottom-gate, bottom-contact organic thin film transistors (OTFTs) were fabricated using solvent soluble copper 1,4,8,11,15,18,22,25-octakis(hexyl)phthalocyanine as the active semiconductor layer. The compound was deposited as 70 nm thick spin-coated films onto gold source–drain electrodes supported on octadecyltrichlorosilane treated 250 nm thick SiO2 gate insulators. The performance of the OTFTs was optimised by investigating the effects of vacuum annealing of the films at temperatures between 50 0C and 200 0C, a range that included the thermotropic mesophase of the bulk material. These effects were monitored by ultraviolet-visible absorption spectroscopy, atomic force microscopy and XRD measurements. Device performance was shown to be dependent upon the annealing temperature due to structural changes of the film. Devices heat treated at 100 0C under vacuum (≥10-7 mbar) were found to exhibit the highest field-effect mobility, 0.7 cm2 V^-1 s^-1, with an on–off current modulation ratio of~107, a reduced threshold voltage of 2.0 V and a sub-threshold swing of 1.11 V per decade.UK Technology Strategy Board (Project no: TP/6/EPH/6/S/K2536J) and UK National Measurement System (Project IRD C02 ‘‘Plastic Electronics’’, 2008–2011)

Planetary and Other Short Binary Microlensing Events from the MOA Short Event Analysis

We present the analysis of four candidate short duration binary microlensing events from the 2006-2007 MOA Project short event analysis. These events were discovered as a byproduct of an analysis designed to find short timescale single lens events that may be due to free-floating planets. Three of these events are determined to be microlensing events, while the fourth is most likely caused by stellar variability. For each of the three microlensing events, the signal is almost entirely due to a brief caustic feature with little or no lensing attributable mainly to the lens primary. One of these events, MOA-bin-1, is due to a planet, and it is the first example of a planetary event in which stellar host is only detected through binary microlensing effects. The mass ratio and separation are q = 4.9 +- 1.4 x 10^{-3} and s = 2.10 +- 0.05, respectively. A Bayesian analysis based on a standard Galactic model indicates that the planet, MOA-bin-1Lb, has a mass of m_p = 3.7 +- 2.1 M_{Jup}, and orbits a star of M_* = 0.75{+0.33 -0.41} M_solar at a semi-major axis of a = 8.3 {+4.5 -2.7} AU. This is one of the most massive and widest separation planets found by microlensing. The scarcity of such wide separation planets also has implications for interpretation of the isolated planetary mass objects found by this analysis. If we assume that we have been able to detect wide separation planets with a efficiency at least as high as that for isolated planets, then we can set limits on the distribution on planets in wide orbits. In particular, if the entire isolated planet sample found by Sumi et al. (2011) consists of planets bound in wide orbits around stars, we find that it is likely that the median orbital semi-major axis is > 30 AU.Comment: 47 pages with 14 figure

Quasiparticle dynamics in ferromagnetic compounds of the Co-Fe and Ni-Fe systems

We report a theoretical study of the quasiparticle lifetime and the quasiparticle mean free path caused by inelastic electron-electron scattering in ferromagnetic compounds of the Co-Fe and Ni-Fe systems. The study is based on spin-polarized calculations, which are performed within the $GW$ approximation for equiatomic and Co- and Ni-rich compounds, as well as for their constituents. We mainly focus on the spin asymmetry of the quasiparticle properties, which leads to the spin-filtering effect experimentally observed in spin-dependent transport of hot electrons and holes in the systems under study. By comparing with available experimental data on the attenuation length, we estimate the contribution of the inelastic mean free path to the latter.Comment: 10 pages, 10 figure

N=4 Twisted Superspace from Dirac-Kahler Twist and Off-shell SUSY Invariant Actions in Four Dimensions

We propose N=4 twisted superspace formalism in four dimensions by introducing Dirac-Kahler twist. In addition to the BRST charge as a scalar counter part of twisted supercharge we find vector and tensor twisted supercharges. By introducing twisted chiral superfield we explicitly construct off-shell twisted N=4 SUSY invariant action. We can propose variety of supergauge invariant actions by introducing twisted vector superfield. We may, however, need to find further constraints to identify twisted N=4 super Yang-Mills action. We propose a superconnection formalism of twisted superspace where constraints play a crucial role. It turns out that N=4 superalgebra of Dirac-Kahler twist can be decomposed into N=2 sectors. We can then construct twisted N=2 super Yang-Mills actions by the superconnection formalism of twisted superspace in two and four dimensions.Comment: 62page

Scaling of Star Polymers with one to 80 Arms

We present large statistics simulations of 3-dimensional star polymers with up to $f=80$ arms, and with up to 4000 monomers per arm for small values of $f$. They were done for the Domb-Joyce model on the simple cubic lattice. This is a model with soft core exclusion which allows multiple occupancy of sites but punishes each same-site pair of monomers with a Boltzmann factor $v<1$. We use this to allow all arms to be attached at the central site, and we use the `magic' value $v=0.6$ to minimize corrections to scaling. The simulations are made with a very efficient chain growth algorithm with resampling, PERM, modified to allow simultaneous growth of all arms. This allows us to measure not only the swelling (as observed from the center-to-end distances), but also the partition sum. The latter gives very precise estimates of the critical exponents $\gamma_f$. For completeness we made also extensive simulations of linear (unbranched) polymers which give the best estimates for the exponent $\gamma$.Comment: 7 pages, 7 figure