6,372 research outputs found
Debt overhang in emerging Europe ?
This paper assesses the extent to which debt overhang poses a constraint to economic activity in Emerging Europe, as the region emerges from the recent financial and economic crisis. At the macroeconomic level, it finds that the external imbalance problem for Emerging Europe has been in most cases more one of flows (high current account deficits in the pre-crisis years) rather than large stocks of external debt. A high reliance on equity funding means that net external debt is far lower than net external liabilities. Domestic balance sheets have expanded quite rapidly but sector liabilities remain relatively low compared with advanced economies. With the important exception of Hungary, public debt levels also remain relatively low in Emerging Europe. At the microeconomic level, the potential for debt overhang in the corporate sector is limited to a few countries: Latvia, Lithuania, Estonia, and Slovenia. Due to the low incidence of household debt, hardly any country, except Estonia, seems to face a threat of debt overhang in the household sector. The strong increase in non-performing loans compared with pre-crisis bank profitability suggests that debt overhang in the banking sector is a threat in Ukraine, Latvia, Lithuania, Hungary, Georgia, and Albania. Financial integration of Emerging Europe seems to have contributed to the transmission of the crisis to the region. At the same time, this integration is helping the region in managing the crisis by concerted actions of the major players.Debt Markets,Access to Finance,Bankruptcy and Resolution of Financial Distress,Banks&Banking Reform,Emerging Markets
Higher-dimensional Algebra and Topological Quantum Field Theory
The study of topological quantum field theories increasingly relies upon
concepts from higher-dimensional algebra such as n-categories and n-vector
spaces. We review progress towards a definition of n-category suited for this
purpose, and outline a program in which n-dimensional TQFTs are to be described
as n-category representations. First we describe a "suspension" operation on
n-categories, and hypothesize that the k-fold suspension of a weak n-category
stabilizes for k >= n+2. We give evidence for this hypothesis and describe its
relation to stable homotopy theory. We then propose a description of
n-dimensional unitary extended TQFTs as weak n-functors from the "free stable
weak n-category with duals on one object" to the n-category of "n-Hilbert
spaces". We conclude by describing n-categorical generalizations of deformation
quantization and the quantum double construction.Comment: 36 pages, LaTeX; this version includes all 36 figure
Exploring the Cosmic Evolution of Habitability with Galaxy Merger Trees
We combine inferred galaxy properties from a semi-analytic galaxy evolution
model incorporating dark matter halo merger trees with new estimates of
supernova and gamma ray burst rates as a function of metallicity from stellar
population synthesis models incorporating binary interactions. We use these to
explore the stellar mass fraction of galaxies irradiated by energetic
astrophysical transients and its evolution over cosmic time, and thus the
fraction which is potentially habitable by life like our own. We find that 18
per cent of the stellar mass in the Universe is likely to have been irradiated
within the last 260 Myr, with GRBs dominating that fraction. We do not see a
strong dependence of irradiated stellar mass fraction on stellar mass or
richness of the galaxy environment. We consider a representative merger tree as
a Local Group analogue, and find that there are galaxies at all masses which
have retained a high habitable fraction (>40 per cent) over the last 6 Gyr, but
also that there are galaxies at all masses where the merger history and
associated star formation have rendered galaxies effectively uninhabitable.
This illustrates the need to consider detailed merger trees when evaluating the
cosmic evolution of habitability.Comment: 11 page, 10 figures. MNRAS accepted 13th Dec 2017. Updated to match
accepted version, with additional discussion of metallicity effect
Resonant and Non-Resonant Effects in Photon-Technipion Production at Lepton Colliders
Lepton collider experiments can search for light technipions in final states
made striking by the presence of an energetic photon: e+e- \to
\photon\technipion. To date, searches have focused on either production
through anomalous coupling of the technipions to electroweak gauge bosons or on
production through a technivector meson (\technirho, \techniomega) resonance.
This paper creates a combined framework in which both contributions are
included. This will allow stronger and more accurate limits on technipion
production to be set using existing data from LEP or future data from a
higher-energy linear collider. We provide explicit formulas and sample
calculations (analytic and Pythia) in the framework of the Technicolor Straw
Man Model, a model that includes light technihadrons.Comment: 11 pages, including title page, 3 figures; version 2: references
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Core excitations across the neutron shell gap in ÂČâ°â·Tl
The single closed-neutron-shell, one proton-hole nucleus 207Tl was populated in deep-inelastic collisions of a 208Pb beam with a 208Pb target. The yrast and near-yrast level scheme has been established up to high excitation energy, comprising an octupol
Topcolor assisted technicolor models and muon anomalous magnetic moment
We discuss and estimate the contributions of the new particles predicted by
topcolor assisted technicolor(TC2) models to the muon anomalous magnetic moment
. Our results show that the contributions of Pseudo Goldstone bosons
are very small which can be safely ignored. The main contributions come from
the ETC gauge boson and topcolor gauge boson . If we
demand that the mass of is consistent with other experimental
constrains, its contributions are smaller than that of . With
reasonable values of the parameters in TC2 models, the observed BNL results for
could be explained.Comment: latex file, 11 pages, several figures and references adde
Two-proton events in the 17F(p,2p)16O reaction
In a recent experimental study (Gomez del Campo et al, PRL 86, 43 (2001)) of
the reaction 17F(p,2p)16O, two-proton events were measured from excitations
near a 1-, E*=6.15 MeV state in 18Ne. We calculate by means of R-matrix theory
the resonant two-proton production cross section and branching ratios. We
conclude that it is unlikely that two-proton production via population of the
1- state is sufficient to explain the observed two-proton events. Alternative
sources of such events are discussed.Comment: 4 pages, 4 figures. Resubmission to Physical Review C (first received
6 March 2001
Multiplicative renormalizability and quark propagator
The renormalized Dyson-Schwinger equation for the quark propagator is
studied, in Landau gauge, in a novel truncation which preserves multiplicative
renormalizability. The renormalization constants are formally eliminated from
the integral equations, and the running coupling explicitly enters the kernels
of the new equations. To construct a truncation which preserves multiplicative
renormalizability, and reproduces the correct leading order perturbative
behavior, non-trivial cancellations involving the full quark-gluon vertex are
assumed in the quark self-energy loop. A model for the running coupling is
introduced, with infrared fixed point in agreement with previous
Dyson-Schwinger studies of the gauge sector, and with correct logarithmic tail.
Dynamical chiral symmetry breaking is investigated, and the generated quark
mass is of the order of the extension of the infrared plateau of the coupling,
and about three times larger than in the Abelian approximation, which violates
multiplicative renormalizability. The generated scale is of the right size for
hadronic phenomenology, without requiring an infrared enhancement of the
running coupling.Comment: 17 pages; minor corrections, comparison to lattice results added;
accepted for publication in Phys. Rev.
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