Effective Governance of Global Financial Markets:An Evolutionary Plan for Reform

Runaway electrons, which are generated in a plasma where the induced electric field exceeds a certain critical value, can reach very high energies in the MeV range. For such energetic electrons, radiative losses will contribute significantly to the momentum space dynamics. Under certain conditions, due to radiative momentum losses, a non-monotonic feature - a ‘bump' - can form in the runaway electron tail, creating a potential for bump-on-tail-type instabilities to arise. Here, we study the conditions for the existence of the bump. We derive an analytical threshold condition for bump appearance and give an approximate expression for the minimum energy at which the bump can appear. Numerical calculations are performed to support the analytical derivation

Similarity Measure Development for Case-Based Reasoning- A Data-driven Approach

In this paper, we demonstrate a data-driven methodology for modelling the local similarity measures of various attributes in a dataset. We analyse the spread in the numerical attributes and estimate their distribution using polynomial function to showcase an approach for deriving strong initial value ranges of numerical attributes and use a non-overlapping distribution for categorical attributes such that the entire similarity range [0,1] is utilized. We use an open source dataset for demonstrating modelling and development of the similarity measures and will present a case-based reasoning (CBR) system that can be used to search for the most relevant similar cases

Synchrotron radiation from a runaway electron distribution in tokamaks

The synchrotron radiation emitted by runaway electrons in a fusion plasma provides information regarding the particle momenta and pitch-angles of the runaway electron population through the strong dependence of the synchrotron spectrum on these parameters. Information about the runaway density and its spatial distribution, as well as the time evolution of the above quantities, can also be deduced. In this paper we present the synchrotron radiation spectra for typical avalanching runaway electron distributions. Spectra obtained for a distribution of electrons are compared to the emission of mono-energetic electrons with a prescribed pitch-angle. We also examine the effects of magnetic field curvature and analyse the sensitivity of the resulting spectrum to perturbations to the runaway distribution. The implications for the deduced runaway electron parameters are discussed. We compare our calculations to experimental data from DIII-D and estimate the maximum observed runaway energy.Comment: 22 pages, 12 figures; updated author affiliations, fixed typos, added a sentence at the end of section I

Discovery and quantitative spectral analysis of an Ofpe/WN9 (WN11) star in the Sculptor spiral galaxy NGC 300

We have discovered an Ofpe/WN9 (WN11 following Smith et al.) star in the Sculptor spiral galaxy NGC 300, the first object of this class found outside the Local Group, during a recent spectroscopic survey of blue supergiant stars obtained at the ESO VLT. The light curve over a five-month period in late 1999 displays a variability at the 0.1 mag level. The intermediate resolution spectra (3800-7200 A) show a very close resemblance to the Galactic LBV AG Car during minimum. We have performed a detailed non-LTE analysis of the stellar spectrum, and have derived a chemical abundance pattern which includes H, He, C, N, O, Al, Si and Fe, in addition to the stellar and wind parameters. The derived stellar properties and the He and N surface enrichments are consistent with those of other Local Group WN11 stars in the literature, suggesting a similar quiescent or post-LBV evolutionary status.Comment: 9 pages, 4 figures, 2 tables. Accepted for publication in the Astrophysical Journal Letter

Telemedicine and Primary Care Obesity Management in Rural Areas– Innovative Approach for Older Adults?

Background: The growing prevalence of obesity is paralleling a rise in the older adult population creating an increased risk of functional impairment, nursing home placement and early mortality. The Centers for Medicare and Medicaid recognized the importance of treating obesity and instituted a benefit in primary care settings to encourage intensive behavioral therapy in beneficiaries by primary care clinicians. This benefit covers frequent, brief, clinic visits designed to address older adult obesity. Discussion: We describe the challenges in the implementation and delivery into real-world settings. The challenges in rural settings that have the fastest growing elderly population, high obesity rates, but also workforce shortages and lack of specialized services are emphasized. The use of Telemedicine has successfully been implemented in other specialties and could be a useful modality in delivering much needed intensive behavioral therapy, particularly in distant, under-resourced environments. This review outlines some of the challenges with the current benefit and proposed solutions in overcoming rural primary care barriers to implementation, including changes in staffing models. Conclusions: Recommendations to extend the benefit’s coverage to be more inclusive of non-physician team members is needed but also for improvement in reimbursement for telemedicine services for older adults with obesity

Chandra HETGS Multi-Phase Spectroscopy of the Young Magnetic O Star theta^1 Orionis C

We report on four Chandra grating observations of the oblique magnetic rotator theta^1 Ori C (O5.5 V) covering a wide range of viewing angles with respect to the star's 1060 G dipole magnetic field. We employ line-width and centroid analyses to study the dynamics of the X-ray emitting plasma in the circumstellar environment, as well as line-ratio diagnostics to constrain the spatial location, and global spectral modeling to constrain the temperature distribution and abundances of the very hot plasma. We investigate these diagnostics as a function of viewing angle and analyze them in conjunction with new MHD simulations of the magnetically channeled wind shock mechanism on theta^1 Ori C. This model fits all the data surprisingly well, predicting the temperature, luminosity, and occultation of the X-ray emitting plasma with rotation phase.Comment: 52 pages, 14 figures (1 color), 6 tables. To appear in the Astrophysical Journal, 1 August 2005, v628, issue 2. New version corrects e-mail address, figure and table formatting problem

Spectroscopic and photometric oscillatory envelope variability during the S Doradus outburst of the Luminous Blue Variable R71

To better understand the LBV phenomenon, we analyze multi-epoch and multi-wavelength spectra and photometry of R71. Pre-outburst spectra are analyzed with the radiative transfer code CMFGEN to determine the star's fundamental stellar parameters. During quiescence, R71 has an effective temperature of $T_\mathrm{{eff}} = 15\,500~K$ and a luminosity of log$(L_*/L_{\odot})$ = 5.78 and is thus a classical LBV, but at the lower luminosity end of this group. We determine its mass-loss rate to $4.0 \times 10^{-6}~M_{\odot}~$yr$^{-1}$. We present R71's spectral energy distribution from the near-ultraviolet to the mid-infrared during its present outburst. Mid-infrared observations suggest that we are witnessing dust formation and grain evolution. Semi-regular oscillatory variability in the star's light curve is observed during the current outburst. Absorption lines develop a second blue component on a timescale twice that length. The variability may consist of one (quasi-)periodic component with P ~ 425/850 d with additional variations superimposed. During its current S Doradus outburst, R71 occupies a region in the HR diagram at the high-luminosity extension of the Cepheid instability strip and exhibits similar irregular variations as RV Tau variables. LBVs do not pass the Cepheid instability strip because of core evolution, but they develop comparable cool, low-mass, extended atmospheres in which convective instabilities may occur. As in the case of RV Tau variables, the occurrence of double absorption lines with an apparent regular cycle may be due to shocks within the atmosphere and period doubling may explain the factor of two in the lengths of the photometric and spectroscopic cycles.Comment: 18 pages, 14 figures, submitted to A&

Extended Magnetic Dome Induced by Low Pressures in Superconducting FeSe1-x_\mathrm{1\text{-}x}Sx_\mathrm{x}

We report muon spin rotation ($\mu$SR) and magnetization measurements under pressure on Fe$_{1+\delta}$Se$_\mathrm{1\text{-}x}$S$_\mathrm{x}$ with x $\approx 0.11$.Above $p\approx0.6$ GPa we find microscopic coexistence of superconductivity with an extended dome of long range magnetic order that spans a pressure range between previously reported separated magnetic phases. The magnetism initially competes on an atomic scale with the coexisting superconductivity leading to a local maximum and minimum of the superconducting $T_\mathrm{c}(p)$. The maximum of $T_\mathrm{c}$ corresponds to the onset of magnetism while the minimum coincides with the pressure of strongest competition. A shift of the maximum of $T_\mathrm{c}(p)$ for a series of single crystals with x up to 0.14 roughly extrapolates to a putative magnetic and superconducting state at ambient pressure for x $\geq0.2$.Comment: 10 pages, 6 figures, including supplemental materia