8,542 research outputs found
Insurance Contracts and Securitization
High correlations between risks can increase required insurer capital and/orreduce the availability of insurance. For such insurance lines, securitizationis rapidly emerging as an alternative form of risk transfer. The ultimatesuccess of securitization in replacing or complementing traditional insuranceand reinsurance products depends on the ability of securitization to facilitateand/or be facilitated by insurance contracts. We consider how insuredlosses might be decomposed into separate components, one of which is atype of “systemic risk” that is highly correlated amongst insureds. Such acorrelated component might conceivably be hedged directly by individuals,but is more likely to be hedged by the insurer. We examine how insurancecontracts may be designed to allow the insured a mechanism to retain all orpart of the systemic component. Examples are provided, which illustrate ourmethodology in several types of insurance markets subject to systemic risk.
Prospective system analysis of the pre- and early hospital care in severe head injury in Bavaria at a population-based level
Deformations of Fuchsian Systems of Linear Differential Equations and the Schlesinger System
We consider holomorphic deformations of Fuchsian systems parameterized by the
pole loci. It is well known that, in the case when the residue matrices are
non-resonant, such a deformation is isomonodromic if and only if the residue
matrices satisfy the Schlesinger system with respect to the parameter. Without
the non-resonance condition this result fails: there exist non-Schlesinger
isomonodromic deformations. In the present article we introduce the class of
the so-called isoprincipal deformations of Fuchsian systems. Every isoprincipal
deformation is also an isomonodromic one. In general, the class of the
isomonodromic deformations is much richer than the class of the isoprincipal
deformations, but in the non-resonant case these classes coincide. We prove
that a deformation is isoprincipal if and only if the residue matrices satisfy
the Schlesinger system. This theorem holds in the general case, without any
assumptions on the spectra of the residue matrices of the deformation. An
explicit example illustrating isomonodromic deformations, which are neither
isoprincipal nor meromorphic with respect to the parameter, is also given
Quantum-classical transition and quantum activation of ratchet currents in the parameter space
The quantum ratchet current is studied in the parameter space of the
dissipative kicked rotor model coupled to a zero temperature quantum
environment. We show that vacuum fluctuations blur the generic isoperiodic
stable structures found in the classical case. Such structures tend to survive
when a measure of statistical dependence between the quantum and classical
currents are displayed in the parameter space. In addition, we show that
quantum fluctuations can be used to overcome transport barriers in the phase
space. Related quantum ratchet current activation regions are spotted in the
parameter space. Results are discussed {based on quantum, semiclassical and
classical calculations. While the semiclassical dynamics involves vacuum
fluctuations, the classical map is driven by thermal noise.Comment: 6 pages, 3 figure
Soft Manifold Dynamics Behind Negative Thermal Expansion
Minimal models are developed to examine the origin of large negative thermal
expansion (NTE) in under-constrained systems. The dynamics of these models
reveals how underconstraint can organize a thermodynamically extensive manifold
of low-energy modes which not only drives NTE but extends across the Brillioun
zone. Mixing of twist and translation in the eigenvectors of these modes, for
which in ZrW2O8 there is evidence from infrared and neutron scattering
measurements, emerges naturally in our model as a signature of the dynamics of
underconstraint.Comment: 5 pages, 3 figure
Electric Field Effect Analysis of Thin PbTe films on high-epsilon SrTiO3 Substrate
Thin PbTe films (thickness 500 - 600 angstrom), deposited on SrTiO3, have
been investigated by electric field effect (EFE). The high resistivity of such
thin films warrants a high sensitivity of the EFE method. The SrTiO3 substrate
serves as the dielectric layer in the Gate-Dielectric-PbTe structure. Due to
the large dielectric constant of SrTiO3, particularly at low temperatures, the
electric displacement D in the film reaches the high value of about 10^8 V/cm,
and the EFE introduced charge into the PbTe film amounts to ~ 8 microC/cm2. The
high D permits to measure the EFE resistance and Hall constant over a wide
region of D, revealing the characteristic features of their D-dependence. An
appropriate theoretical model has been formulated, showing that, for such
films, one can measure the dependence of the Fermi level on D. In fact, we
demonstrate that shifting the Fermi level across the gap by varying D, the
density-of-states of the in-gape states can be mapped out. Our results show,
that the PbTe layers studied, possess a mobility gap exceeding the gap of bulk
PbTe.Comment: 27 pages, 12 figure
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