12,918 research outputs found
Pan-European Chikungunya surveillance: Designing risk stratified surveillance zones
This article has been made available through the Brunel Open Access Publishing Fund - Copyright @ 2009 Tilston et alThe first documented transmission of Chikungunya within Europe took place in Italy during the summer of 2007. Chikungunya, a viral infection affecting millions of people across Africa and Asia, can be debilitating and no prophylactic treatment exists. Although imported cases are reported frequently across Europe, 2007 was the first confirmed European outbreak and available evidence suggests that Aedes albopictus was the vector responsible and the index case was a visitor from India. This paper proposed pan-European surveillance zones for Chikungunya, based on the climatic conditions necessary for vector activity and viral transmission. Pan-European surveillance provides the best hope for an early-warning of outbreaks, because national boundaries do not play a role in defining the risk of this new vector borne disease threat. A review of climates, where Chikungunya has been active, was used to inform the delineation of three pan-European surveillance zones. These vary in size each month across the June-September period of greatest risk. The zones stretch across southern Europe from Portugal to Turkey. Although the focus of this study was to define the geography of potential surveillance zones based on the climatic limits on the vector and virus, a preliminary examination of inward bound airline passengers was also undertaken. This indicated that France and Italy are likely to be at greater risk due to the number of visitors they receive from Chikungunya active regions, principally viraemic visitors from India. Therefore this study represents a first attempt at creating risk stratified surveillance zones, which we believe could be usefully refined with the use of higher resolution climate data and more complete air travel data
Production of scalar molecules in radiative decays
The potentialities of the production of the scalar molecules in the
radiative decays are considered beyond the narrow resonance width
approximation. It is shown that $BR(\phi\rightarrow\gamma
f_0(a_0)\rightarrow\gamma\pi\pi(\pi\eta))\approx (1\div 2)\times 10^{-5}\
,\BR(\phi\rightarrow\gamma (f_0+a_0)\rightarrow\gamma K^+K^-)\alt 10^{-6}BR(\phi\rightarrow\gamma (f_0+a_0) \to \gamma K^0\bar K^0)\alt 10^{-8}\pi\pi\ ,\ \pi\eta\ ,\ K^+K^-\ ,\ K^0\bar K^0\phi\rightarrow\gamma
f_0(a_0)e^+e^-\rightarrow\gamma \pi^+\pi^-\phi$ meson mass region.Comment: 19 pages, revtex, 4 eps files of figure
The quantization of the symplectic groupoid of the standard Podles sphere
We give an explicit form of the symplectic groupoid that integrates the
semiclassical standard Podles sphere. We show that Sheu's groupoid, whose
convolution C*-algebra quantizes the sphere, appears as the groupoid of the
Bohr-Sommerfeld leaves of a (singular) real polarization of the symplectic
groupoid. By using a complex polarization we recover the convolution algebra on
the space of polarized sections. We stress the role of the modular class in the
definition of the scalar product in order to get the correct quantum space.Comment: 33 pages; minor correction
An effectual template bank for the detection of gravitational waves from inspiralling compact binaries with generic spins
We report the construction of a three-dimensional template bank for the
search for gravitational waves from inspiralling binaries consisting of
spinning compact objects. The parameter space consists of two dimensions
describing the mass parameters and one "reduced-spin" parameter, which
describes the secular (non-precessing) spin effects in the waveform. The
template placement is based on an efficient stochastic algorithm and makes use
of the semi-analytical computation of a metric in the parameter space. We
demonstrate that for "low-mass" () binaries,
this template bank achieves effective fitting factors --
towards signals from generic spinning binaries in the advanced detector era
over the entire parameter space of interest (including binary neutron stars,
binary black holes, and black hole-neutron star binaries). This provides a
powerful and viable method for searching for gravitational waves from generic
spinning low-mass compact binaries. Under the assumption that spin magnitudes
of black-holes [neutron-stars] are uniformly distributed between 0--0.98 [0 --
0.4] and spin angles are isotropically distributed, the expected improvement in
the average detection volume (at a fixed signal-to-noise-ratio threshold) of a
search using this reduced-spin bank is , as compared to a search
using a non-spinning bank.Comment: Minor changes, version appeared in Phys. Rev.
Financial Regulation in the (Receding) Shadow of Antitrust
Mounting evidence that a number of key industries in the U.S. economy have become less competitive in recent years is prompting a renewed national conversation about an enhanced role for antitrust enforcement. But there are limits on the anticompetitive conduct antitrust enforcers and private plaintiffs can reach, especially in regulated markets. This is due in part to the doctrine of implied antitrust immunity: when a court perceives a conflict between the antitrust laws (e.g., the Sherman Act) and a regulatory regime (e.g., the securities laws), it may find immunity for conduct that otherwise would violate the antitrust laws. Two Supreme Court cases from the 2000s, Verizon Communications Inc. v. Law Offices of Curtis V. Trinko and Credit Suisse v. Billing, appeared to enhance these restrictions, seemingly increasing the likelihood that regulation will displace antitrust entirely. This Article argues that these cases have had a surprisingly limited impact in most regulated markets, but have affected the scope of implied immunity in the financial markets. As a result, the job of confronting heightened concentration and reduced competition in financial services may fall to sector regulators, especially the Securities & Exchange Commission and Commodity Futures Trading Commission. But these agencies are unprepared for the task and often are unwilling to undertake it. They have neither the resources nor personnel to enforce competition rules and such enforcement ranks low on their priority list. Competition in financial markets therefore may suffer. The stakes are high: increased concentration in financial markets harms consumers and may threaten systemic financial safety. In light of the sector regulators’ limitations, this Article proposes a regulatory-design solution to the problem of competition enforcement in financial markets and focuses on Dodd-Frank’s regulatory regime for the derivatives markets as a case study. It argues that sector regulators should craft structural rules to protect competition in these markets ex ante rather than solely relying on conduct rules and corrective measures taken ex post. The Article contends that increased reliance on structural regulatory responses to competition problems in regulated markets may be beneficial from a competition standpoint when compared to antitrust enforcement and that these salutary effects may be enhanced when the products involved are potentially toxic, as is the case for some derivatives products. This approach is particularly crucial for the derivatives markets, which are enormous, continue to grow, and pose serious competition and systemic risks that may spill over into the wider economy
Blockchain Neutrality
Blockchain technology is transforming how markets work.Blockchains eliminate the need for trusted gatekeepers likebanks to execute, verify, and record transactions. In thefinancial markets, their disruptive potential threatens bothWall Street banks and Silicon Valley venture capitalists. Howblockchain technology is regulated will determine whether itencourages or inhibits competition. Some blockchainapplications present serious fraud and systemic risks,complicating regulation. This Article explores the antitrust andcompetition policy challenges blockchain presents and proposesa regulatory strategy, modeled on Internet regulation and netneutrality principles, to unlock blockchain’s competitivepotential. It contends that financial regulators should promoteblockchain competition—and the resulting marketdecentralization—except in cases where specific applicationsare shown to harm consumers or threaten systemic safety.Regulators also should ensure open access and non-discrimination on dominant blockchain networks. Thisapproach will not only serve traditional antitrust goals oflowering prices and promoting innovation, but it also mightachieve broader economic and social reform by reducing thepower and influence of the biggest financial institutions
Four-quark state in QCD
The spectra of some 0++ four-quark states, which are composed of \bar qq
pairs, are calculated in QCD. The light four-quark states are calculated using
the traditional sum rules while four-quark states containing one heavy quark
are computed in HQET. For constructing the interpolating currents, different
couplings of the color and spin inside the \bar qq pair are taken into account.
It is found that the spin and color combination has little effect on the mass
of the four-quark states.Comment: 10 pages, 4 ps figures, Late
Coisotropic submanifolds in Poisson geometry and branes in the Poisson sigma model
General boundary conditions ("branes") for the Poisson sigma model are
studied. They turn out to be labeled by coisotropic submanifolds of the given
Poisson manifold. The role played by these boundary conditions both at the
classical and at the perturbative quantum level is discussed. It turns out to
be related at the classical level to the category of Poisson manifolds with
dual pairs as morphisms and at the perturbative quantum level to the category
of associative algebras (deforming algebras of functions on Poisson manifolds)
with bimodules as morphisms. Possibly singular Poisson manifolds arising from
reduction enter naturally into the picture and, in particular, the construction
yields (under certain assumptions) their deformation quantization.Comment: 21 pages, 2 figures; minor corrections, references updated; final
versio
Fission-gas-release rates from irradiated uranium nitride specimens
Fission-gas-release rates from two 93 percent dense UN specimens were measured using a sweep gas facility. Specimen burnup rates averaged .0045 and .0032 percent/hr, and the specimen temperatures ranged from 425 to 1323 K and from 552 to 1502 K, respectively. Burnups up to 7.8 percent were achieved. Fission-gas-release rates first decreased then increased with burnup. Extensive interconnected intergranular porosity formed in the specimen operated at over 1500 K. Release rate variation with both burnup and temperature agreed with previous irradiation test results
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