1,241 research outputs found
Medical Tourism in Barbados: Negotiating Inherent Tensions
This chapter draws on our long term-research program examining medical tourism in Barbados and the wider Anglophone Caribbean. Since 2011 we have undertaken 69 semi-structured interviews and three focus groups with a wide range of health system and tourism sector stakeholders in Barbados, compiled a comprehensive collection of state and media reports discussing medical tourism, and collectively spent over a year conducting on-site ethnographic fieldwork that has included many informal conversations with users of the Barbadian health system from a wide range of backgrounds. Together, these datasets and experiences provide a rich understanding of the potential considerations and hopes arising from the ongoing discussion about medical tourism development in a small island setting. Exploring these considerations and hopes suggests ways in which Barbados and other small island states seeking to develop their medical tourism sectors can negotiate a structure for medical tourism that can best meet their development goals
Far-infrared vibrational properties of high-pressure-high-temperature C60 polymers and the C60 dimer
We report high-resolution far-infrared transmission measurements of the 2 + 2 cycloaddition C-60 dimer and two-dimensional rhombohedral and one-dimensional orthorhombic high-pressure high-temperature C60 polymers. In the spectral region investigated(20-650 cm(-1)), we see no low-energy interball modes, but symmetry breaking of the linked C-60 balls is evident in the complex spectrum of intramolecular modes. Experimental features suggest large splittings or frequency shifts of some IhC60-derived modes that are activated by symmetry reduction, implying that the balls are strongly distorted in these structures. We have calculated the vibrations of all three systems by first-principles quantum molecular dynamics and use them to assign the predominant IhC60 symmetries of observed modes. Pur calculations show unprecedentedly large downshifts of T-1u(2)-derived modes and extremely large splittings of other modes, both of which are consistent with the experimental spectra. For the rhombohedral and orthorhombic polymers, the T-1u(2)-derived mode that is polarized along the bonding direction is calculated to downshift below any T-1u(1)-derived modes. We also identify a previously unassigned feature near 610 cm(-1) in all three systems as a widely split or shifted mode derived from various silent IhC60 vibrations, confirming a strong perturbation model for these linked fullerene structures
Large Deviations in the Superstable Weakly Imperfect Bose Gas
The superstable Weakly Imperfect Bose Gas {(WIBG)} was originally derived to
solve the inconsistency of the Bogoliubov theory of superfluidity. Its
grand-canonical thermodynamics was recently solved but not at {point of} the
{(first order)} phase transition. This paper proposes to close this gap by
using the large deviations formalism and in particular the analysis of the Kac
distribution function. It turns out that, as a function of the chemical
potential, the discontinuity of the Bose condensate density at the phase
transition {point} disappears as a function of the particle density. Indeed,
the Bose condensate continuously starts at the first critical particle density
and progressively grows but the free-energy per particle stays constant until
the second critical density is reached. At higher particle densities, the Bose
condensate density as well as the free-energy per particle both increase
{monotonously}
Anisotropic flows from initial state of a fast nucleus
We analyze azimuthal anisotropy in heavy ion collisions related to the
reaction plane in terms of standard reggeon approach and find that it is
nonzero even when the final state interaction is switched off. This effect can
be interpreted in terms of partonic structure of colliding nuclei. We use
Feynman diagram analysis to describe details of this mechanism. Main
qualitative features of the appropriate azimuthal correlations are discussed.Comment: 16 pages, 11 figures. This paper is an extended version of a talk
given at Session of Nuclear Physics Division of Russian Academy of Sciences
in November 200
Acute inhibition of MEK suppresses congenital melanocytic nevus syndrome in a murine model driven by activated NRAS and Wnt signaling
Congenital melanocytic nevus (CMN) syndrome is the association of pigmented melanocytic nevi with extra-cutaneous features, classically melanotic cells within the central nervous system, most frequently caused by a mutation of NRAS codon 61. This condition is currently untreatable and carries a significant risk of melanoma within the skin, brain, or leptomeninges. We have previously proposed a key role for Wnt signaling in the formation of melanocytic nevi, suggesting that activated Wnt signaling may be synergistic with activated NRAS in the pathogenesis of CMN syndrome. Some familial pre-disposition suggests a germ-line contribution to CMN syndrome, as does variability of neurological phenotypes in individuals with similar cutaneous phenotypes. Accordingly, we performed exome sequencing of germ-line DNA from patients with CMN to reveal rare or undescribed Wnt-signaling alterations. A murine model harboring activated NRASQ61K and Wnt signaling in melanocytes exhibited striking features of CMN syndrome, in particular neurological involvement. In the first model of treatment for this condition, these congenital, and previously assumed permanent, features were profoundly suppressed by acute post-natal treatment with a MEK inhibitor. These data suggest that activated NRAS and aberrant Wnt signaling conspire to drive CMN syndrome. Post-natal MEK inhibition is a potential candidate therapy for patients with this debilitating condition
Causality, Analyticity and an IR Obstruction to UV Completion
We argue that certain apparently consistent low-energy effective field
theories described by local, Lorentz-invariant Lagrangians, secretly exhibit
macroscopic non-locality and cannot be embedded in any UV theory whose S-matrix
satisfies canonical analyticity constraints. The obstruction involves the signs
of a set of leading irrelevant operators, which must be strictly positive to
ensure UV analyticity. An IR manifestation of this restriction is that the
"wrong" signs lead to superluminal fluctuations around non-trivial backgrounds,
making it impossible to define local, causal evolution, and implying a
surprising IR breakdown of the effective theory. Such effective theories can
not arise in quantum field theories or weakly coupled string theories, whose
S-matrices satisfy the usual analyticity properties. This conclusion applies to
the DGP brane-world model modifying gravity in the IR, giving a simple
explanation for the difficulty of embedding this model into controlled stringy
backgrounds, and to models of electroweak symmetry breaking that predict
negative anomalous quartic couplings for the W and Z. Conversely, any
experimental support for the DGP model, or measured negative signs for
anomalous quartic gauge boson couplings at future accelerators, would
constitute direct evidence for the existence of superluminality and macroscopic
non-locality unlike anything previously seen in physics, and almost
incidentally falsify both local quantum field theory and perturbative string
theory.Comment: 34 pages, 10 figures; v2: analyticity arguments improved, discussion
on non-commutative theories and minor clarifications adde
Parametrized Post-Newtonian Orbital Effects in Extrasolar Planets
Perturbative Post-Newtonian variations of the standard osculating orbital
elements are obtained by using the two-body equations of motion in the
Parameterized Post-Newtonian theoretical framework. The results obtained are
applied to the Einstein and. Brans - Dicke theories. As a results, the
semi-major axis and eccentricity exhibit periodic variation, but no secular
changes.. The longitude of periastron and mean longitude at epoch experience
both secular and periodic shifts. The Post-Newtonian effects are calculated and
discussed for six extrasolar planets.Comment: Accepted for publication in Astrophys. Space Sc
Quasilinear hyperbolic Fuchsian systems and AVTD behavior in T2-symmetric vacuum spacetimes
We set up the singular initial value problem for quasilinear hyperbolic
Fuchsian systems of first order and establish an existence and uniqueness
theory for this problem with smooth data and smooth coefficients (and with even
lower regularity). We apply this theory in order to show the existence of
smooth (generally not analytic) T2-symmetric solutions to the vacuum Einstein
equations, which exhibit AVTD (asymptotically velocity term dominated) behavior
in the neighborhood of their singularities and are polarized or half-polarized.Comment: 78 page
Decays of the Exotic Hybrid and - Mixing
QCD sum-rules are used to calculate the decay widths of the exotic hybrid in two different
mixing schemes.
In the conventional flavour octet-singlet mixing scheme, the decay widths are
both found to be small, while in the recently-proposed quark mixing scheme, the
decay width is large compared with
the decay width . These
results provide some insight into - mixing and hybrid decay
features.Comment: latex2e, 11 pages with 4 embedded eps figures. v 2 corrects reference
[5] and minor error in equation (11
- …