4,310 research outputs found
Vortex and droplet in holographic D-wave superconductors
We investigate non-trivial localized solutions of the condensate in a
(2+1)-dimensional D-wave holographic superconductor model in the presence of a
background magnetic field. The calculation is done in the context of the
(3+1)-dimensional dual gravity theory of a charged massive spin-2 field in an
AdS black hole background. By using numeric techniques, we find both vortex and
droplet solutions. These solutions are important for studying the full phase
diagram of D-wave superconductors.Comment: 9 pages, 8 figures, several references were added, to appear in Phys.
Lett.
Positive lifestyle behaviours and emotional health factors are associated with low back pain resilience
Purpose: To evaluate the relationship between lifestyle behaviours, emotional health factors, and low back pain (LBP) resilience. Methods: This retrospective longitudinal study utilised 1,065 twins with a recent history of LBP from the Washington State Twin Registry. A lifestyle behaviour score was built using variables of body mass index, physical activity engagement, sleep quality, smoking status, and alcohol consumption. An emotional health score was built using variables of the absence of depressed mood, perceived stress, and active coping. The main outcome was LBP resilience, assessed as recovery (“bouncing back”), and sustainability (maintaining high levels of function despite LBP). Results: After adjusting for covariates, there was no relationship between the lifestyle behaviour score (OR 1.05, 95% CI 0.97–1.15, p = 0.218) and the emotional health score (OR 1.08, 95% CI 0.98–1.19, p = 0.142) with the likelihood of recovering from LBP. There was however, evidence of a positive association between the lifestyle behaviour score (β 0.20, 95% CI 0.04–0.36, p = 0.013), the emotional health score (β 0.22, 95% CI 0.00–0.43, p = 0.049), and greater levels of sustainability. These results were confirmed by a within-pair analysis (lifestyle behaviour score: β 1.79, 95% CI 0.05–3.53, p = 0.043) and (emotional health score: β 0.52, 95% CI 0.09–0.96, p = 0.021) adjusting for genetic and early shared environmental confounding. Conclusion: Findings from this study suggest that people who adopt optimal lifestyle behaviours and positive emotional factors are more likely to be resilient and maintain high levels of function despite suffering from LBP
Identification of dynamic displacements and modal frequencies of amedium-span suspension bridge using multimode GNSS processing
Global Navigation Satellite System (GNSS) positioning technology has been employed in the dynamic monitoring of long-span bridges in the recent years. However, it has difficulties to meet the higher accuracy requirements of the dynamic monitoring of small or medium span bridges, due to the presence of measurement noise from multipath, cycle slips, ionosphere delay, orbital errors, etc. To verify the feasibility of using current GNSS technology to monitor these bridges, a series of monitoring experiments have been carried out on the Wilford suspension bridge in Nottingham (UK) with GNSS and a triaxial accelerometer. Three GNSS data processing modes, i.e. Real-Time Kinematic (RTK), network RTK and Post-Processing Kinematic (PPK), were considered. An innovative multimode adaptive filtering (MAF) that combining adaptive filter with Chebyshev highpass filter was used to identify the dynamic displacements of the bridge from the multimode GNSS data. To validate the GNSS results, the dynamic displacements were also computed from double integration of the accelerometer-measured accelerations. The differences of the displacements between the GNSS and accelerometer results were obtained. The standard deviation and the mean deviation of these differences are less than 1 mm, which is good enough for the monitoring purposes. The modal frequencies of the bridge can be accurately identified from GNSS measurements, and successfully validated by those from the accelerometer data. Using the multimode GNSS data and the proposed the MAF algorithm, with sub-millimeter level accuracy GNSS can be used to monitor the vibration response of small or medium span bridges as well as long-span bridges
Irreducible characters of GSp(4, q) and dimensions of spaces of fixed vectors
In this paper, we compute the conjugacy classes and the list of irreducible
characters of GSp(4,q), where q is odd. We also determine precisely which
irreducible characters are non-cuspidal and which are generic. These characters
are then used to compute dimensions of certain subspaces of fixed vectors of
smooth admissible non-supercuspidal representations of GSp(4,F), where F is a
non-archimedean local field of characteristic zero with residue field of order
q.Comment: 48 pages, 21 tables. Corrected an error in Table 16 for type V*
representations (theta_11 and theta_12 were switched
Berry Phase in Atom-Molecule Conversion Systems and Fractional Monopole
We investigate the geometric phase or Berry phase of adiabatic quantum
evolution in an atom-molecule conversion system, and find that the Berry phase
in such system consists of two parts: the usual Berry connection term and a
novel term from the nonlinearity brought forth by the atom-molecule conversion.
The geometric phase can be viewed as the flux of the magnetic field of a
monopole through the surface enclosed by a closed path in parameter space. The
charge of the monopole, however, is found to be one third of the elementary
charge of the usual quantized monopole.Comment: 4 pages, 1 figur
Multifrequency Strategies for the Identification of Gamma-Ray Sources
More than half the sources in the Third EGRET (3EG) catalog have no firmly
established counterparts at other wavelengths and are unidentified. Some of
these unidentified sources have remained a mystery since the first surveys of
the gamma-ray sky with the COS-B satellite. The unidentified sources generally
have large error circles, and finding counterparts has often been a challenging
job. A multiwavelength approach, using X-ray, optical, and radio data, is often
needed to understand the nature of these sources. This chapter reviews the
technique of identification of EGRET sources using multiwavelength studies of
the gamma-ray fields.Comment: 35 pages, 22 figures. Chapter prepared for the book "Cosmic Gamma-ray
Sources", edited by K.S. Cheng and G.E. Romero, to be published by Kluwer
Academic Press, 2004. For complete article and higher resolution figures, go
to: http://www.astro.columbia.edu/~muk/mukherjee_multiwave.pd
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