8,568 research outputs found
MARAN 2009 : Monitoring of antimicrobial resistance and antibiotic usage in animals in the Netherlands in 2009
N=2 Rigid Supersymmetry with Gauged Central Charge
We develop a general setting for N=2 rigid supersymmetric field theories with
gauged central charge in harmonic superspace. We consider those N=2 multiplets
which have a finite number of off-shell components and exist off shell owing to
a non-trivial central charge. This class includes, in particular, the
hypermultiplet with central charge and various versions of the vector-tensor
multiplet. For such theories we present a manifestly supersymmetric universal
action. Chern-Simons couplings to an external N=2 super Yang-Mills multiplet
are given, in harmonic superspace, for both the linear and nonlinear
vector-tensor multiplets with gauged central charge. We show how to deduce the
linear version of the vector-tensor multiplet from six dimensions.Comment: 46 pages, latex, no figure
COVID-19 and the difficulty of inferring epidemiological parameters from clinical data
Knowing the infection fatality ratio (IFR) is of crucial importance for
evidence-based epidemic management: for immediate planning; for balancing the
life years saved against the life years lost due to the consequences of
management; and for evaluating the ethical issues associated with the tacit
willingness to pay substantially more for life years lost to the epidemic, than
for those to other diseases. Against this background Verity et al. (2020,
Lancet Infections Diseases) have rapidly assembled case data and used
statistical modelling to infer the IFR for COVID-19. We have attempted an
in-depth statistical review of their approach, to identify to what extent the
data are sufficiently informative about the IFR to play a greater role than the
modelling assumptions, and have tried to identify those assumptions that appear
to play a key role. Given the difficulties with other data sources, we provide
a crude alternative analysis based on the Diamond Princess Cruise ship data and
case data from China, and argue that, given the data problems, modelling of
clinical data to obtain the IFR can only be a stop-gap measure. What is needed
is near direct measurement of epidemic size by PCR and/or antibody testing of
random samples of the at risk population.Comment: Version accepted by the Lancet Infectious Diseases. See previous
version for less terse presentatio
On The spectrum of a Noncommutative Formulation of the D=11 Supermembrane with Winding
A regularized model of the double compactified D=11 supermembrane with
nontrivial winding in terms of SU(N) valued maps is obtained. The condition of
nontrivial winding is described in terms of a nontrivial line bundle introduced
in the formulation of the compactified supermembrane. The multivalued
geometrical objects of the model related to the nontrivial wrapping are
described in terms of a SU(N) geometrical object which in the
limit, converges to the symplectic connection related to the area preserving
diffeomorphisms of the recently obtained non-commutative description of the
compactified D=11 supermembrane.(I. Martin, J.Ovalle, A. Restuccia. 2000,2001)
The SU(N) regularized canonical lagrangian is explicitly obtained. In the limit it converges to the lagrangian in (I.Martin, J.Ovalle,
A.Restuccia. 2000,2001) subject to the nontrivial winding condition. The
spectrum of the hamiltonian of the double compactified D=11 supermembrane is
discussed.
Generically, it contains local string like spikes with zero energy.
However the sector of the theory corresponding to a principle bundle
characterized by the winding number , described by the SU(N) model we
propose, is shown to have no local string-like spikes and hence the spectrum of
this sector should be discrete.Comment: 16 pages.Latex2
A Topologically Massive Gauge Theory with 32 Supercharges
We construct a novel topologically massive abelian Chern-Simons gauge theory
with 32 global supersymmetries in three spacetime dimensions. In spite of the
32 supercharges, the theory exhibits massive excitations only up to spin 1. The
possibility of such a multiplet shortening is due to the presence of
non-central R-symmetry generators in the Poincare superalgebra, whose
supermultiplets are determined.Comment: 20 pages; v2: minor changes, ref. added, to appear in Phys. Rev.
Consistent truncation of d = 11 supergravity on AdS_4 x S^7
We study the system of equations derived twenty five years ago by B. de Wit
and the first author [Nucl. Phys. B281 (1987) 211] as conditions for the
consistent truncation of eleven-dimensional supergravity on AdS_4 x S^7 to
gauged N = 8 supergravity in four dimensions. By exploiting the E_7(7)
symmetry, we determine the most general solution to this system at each point
on the coset space E_7(7)/SU(8). We show that invariants of the general
solution are given by the fluxes in eleven-dimensional supergravity. This
allows us to both clarify the explicit non-linear ansatze for the fluxes given
previously and to fill a gap in the original proof of the consistent
truncation. These results are illustrated with several examples.Comment: 41 pages, typos corrected, published versio
Holographic injection locking of a broad area laser diode via a photorefractive thin-film device
We demonstrate locking of a high power broad area laser diode to a single frequency using holographic feedback from a photorefractive polymer thin-film device for the first time. A four-wave mixing setup is used to generate feedback for the broad area diode at the wavelength of the single frequency source (Ti:Sapphire laser) while the spatial distribution adapts to the preferred profile of the broad area diode. The result is an injection-locked broad area diode emitting with a linewidth comparable to the Ti:Sapphire laser
Comparison of Generic and Proprietary Sodium Stibogluconate for the Treatment of Visceral Leishmaniasis in Kenya.
OBJECTIVE: To compare the use of generic and proprietary sodium stibogluconate for the treatment of visceral leishmaniasis (kala-azar). METHODS: A total of 102 patients with confirmed kala-azar were treated in a mission hospital in West Pokot region, Kenya, with sodium stibogluconate (20 mg/kg/day for 30 days)--either as Pentostam (PSM) or generic sodium stibogluconate (SSG); 51 patients were allocated alternately to each treatment group. FINDINGS: There were no significant differences in baseline demographic characteristics or disease severity, or in events during treatment. There were 3 deaths in the PSM group and 1 in the SSG group; 2 patients defaulted in each group. Only 1 out of 80 test-of-cure splenic aspirates was positive for Leishmania spp.; this patient was in the SSG group. Follow-up after > or = 6 months showed that 6 out of 58 patients had relapsed, 5 in the SSG group and 1 in the PSM group. No outcome variable was significantly different between the two groups. CONCLUSION: The availability of cheaper generic sodium stibogluconate, subject to rigid quality controls, now makes it possible for the health authorities in kala-azar endemic areas to provide treatment to many more patients in Africa
Minimal Stability in Maximal Supergravity
Recently, it has been shown that maximal supergravity allows for
non-supersymmetric AdS critical points that are perturbatively stable. We
investigate this phenomenon of stability without supersymmetry from the
sGoldstino point of view. In particular, we calculate the projection of the
mass matrix onto the sGoldstino directions, and derive the necessary conditions
for stability. Indeed we find a narrow window allowing for stable SUSY breaking
points. As a by-product of our analysis, we find that it seems impossible to
perturb supersymmetric critical points into non-supersymmetric ones: there is a
minimal amount of SUSY breaking in maximal supergravity.Comment: 27 pages, 1 figure. v2: two typos corrected, published versio
An active asteroid belt causing the UX Ori phenomenon in RZ Psc
We report the discovery of mid-infrared excess emission in the young object
RZ Psc. The excess constitutes ~8% of its Lbol, and is well fit by a single
500K black-body implying a dust free region within 0.7AU for optically thick
dust. The object displays dust obscuration events (UXOR behaviour) with a
time-scale that suggests dusty material on orbits of 0.5AU. We also report a
12.4 year cyclical photometric variability which can be interpreted as due to
perturbations in the dust distribution. The system is characterized by a high
inclination, marginal extinction (during bright photometric states), a single
temperature for the warm dust, and an age estimate which puts the star beyond
the formation stage. We propose that the dust occultation events present a
dynamical view of an active asteroid belt whose collisional products
sporadically obscure the central star.Comment: Accepted for A&A letter
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