479 research outputs found
Large deviations for the extended Heston model: the large-time case
We study here the large-time behaviour of all continuous affine stochastic volatility models (in the sense of Keller-Ressel) and deduce a closed-form formula for the large-maturity implied volatility smile. Based on refinements of the Gartner-Ellis theorem on the real line, our proof reveals pathological behaviours of the asymptotic smile. In particular, we show that the condition assumed in Gatheral and Jacquier under which the Heston implied volatility converges to the SVI parameterisation is necessary and sufficient
Superconducting Mg-B films by pulsed laser deposition in an in-situ two-step process using multi-component targets
Superconducting thin films have been prepared in a two-step in-situ process,
using the Mg-B plasma generated by pulsed laser ablation. The target was
composed of a mixture of Mg and MgB2 powders to compensate for the volatility
of Mg and therefore to ensure a high Mg content in the film. The films were
deposited at temperatures ranging from room temperature to 300 degrees C
followed by a low-pressure in-situ annealing procedure. Various substrates have
been used and diverse ways to increase the Mg content into the film were
applied. The films show a sharp transition in the resistance and have a zero
resistance transition temperature of 22-24 K.Comment: 4 pages, 3 figures, submitted to Applied Physics Letter
Procuring load curtailment from local customers under uncertainty
J.M. was supported by EPSRC grant no. EP/K00557X/2, A.M. was partially supported by EPSRC grant EP/P003818/1 and J.V. by a President’s PhD Scholarship from Imperial College London
Superconducting thin films of MgB2 on (001)-Si by pulsed laser deposition
Superconducting thin films have been prepared on Si-substrates, using pulsed
laser deposition from a target composed of a mixture of Mg and MgB2 powders.
The films were deposited at room temperature and post-annealed at 600 degrees
C. The zero resistance transition temperatures were 12 K, with an onset
transition temperature of 27 K. Special care has been taken to avoid oxidation
of Mg in the laser plasma and deposited film, by optimizing the background
pressure of Ar gas in the deposition chamber. For this the optical emission in
the visible range from the plasma has been used as indicator. Preventing Mg
from oxidation was found to be essential to obtain superconducting films
Quantifying High-Order Interactions in Cardiovascular and Cerebrovascular Networks
We present a method to analyze the dynamics of physiological networks beyond the framework of pairwise interactions. Our method defines the so-called O-information rate (OIR) as a measure of the higher-order interaction among several physiological variables. The OIR measure is computed from the vector autoregressive representation of multiple time series, and is applied to the network formed by heart period, systolic and diastolic arterial pressure, respiration and cerebral blood flow variability series measured in healthy subjects at rest and after head-up tilt. Our results document that cardiovascular, cerebrovascular and respiratory interactions are highly redundant, and that redundancy is enhanced by the entrainment of cardiovascular and cerebrovascular oscillations and by sympathetic activation
One-dimensional relativistic dissipative system with constant force and its quantization
For a relativistic particle under a constant force and a linear velocity
dissipation force, a constant of motion is found. Problems are shown for
getting the Hamiltoninan of this system. Thus, the quantization of this system
is carried out through the constant of motion and using the quantization of the
velocity variable. The dissipative relativistic quantum bouncer is outlined
within this quantization approach.Comment: 11 pages, no figure
Light and heavy transfer products in Xe 136 + U 238 multinucleon transfer reactions
A. Vogt et al.; 12 pags.; 14 figs.; PACS number(s): 24.10.−i, 25.70.Hi, 29.30.Aj, 29.40.Gx© 2015 American Physical Society. ©2015 American Physical Society. Background: Multinucleon transfer reactions (MNT) are a competitive tool to populate exotic neutron-rich nuclei in a wide region of nuclei, where other production methods have severe limitations or cannot be used at all. Purpose: Experimental information on the yields of MNT reactions in comparison with theoretical calculations are necessary to make predictions for the production of neutron-rich heavy nuclei. It is crucial to determine the fraction of MNT reaction products which are surviving neutron emission or fission at the high excitation energy after the nucleon exchange. Method: Multinucleon transfer reactions in Xe136+U238 have been measured in a high-resolution γ-ray/particle coincidence experiment. The large solid-angle magnetic spectrometer PRISMA coupled to the high-resolution Advanced Gamma Tracking Array (AGATA) has been employed. Beamlike reaction products after multinucleon transfer in the Xe region were identified and selected with the PRISMA spectrometer. Coincident particles were tagged by multichannel plate detectors placed at the grazing angle of the targetlike recoils inside the scattering chamber. Results: Mass yields have been extracted and compared with calculations based on the grazing model for MNT reactions. Kinematic coincidences between the binary reaction products, i.e., beamlike and targetlike nuclei, were exploited to obtain population yields for nuclei in the actinide region and compared to x-ray yields measured by AGATA. Conclusions: No sizable yield of actinide nuclei beyond Z=93 is found to perform nuclear structure investigations. In-beam γ-ray spectroscopy is feasible for few-neutron transfer channels in U and the -2p channel populating Th isotopes.The research leading to these results has received
funding from the German Bundesministerium fur Bildung ¨
und Forschung (BMBF) under Contract No. 05P12PKFNE
TP4, the European Union Seventh Framework Programme
(FP7/2007-2013) under Grant No. 262010-ENSAR, and the
Spanish Ministerio de Ciencia e Innovacion under Contract ´
No. FPA2011-29854-C04. A.V. thanks the Bonn-Cologne
Graduate School of Physics and Astronomy (BCGS) for
financial support. One of the authors (A. Gadea) was supported
by MINECO, Spain, under Grants No. FPA2011-29854-C04
and No. FPA2014-57196-C5, Generalitat Valenciana, Spain,
under Grant No. PROMETEOII/2014/019, and EU under the
FEDER program.Peer Reviewe
Superconducting Quantum Interference Device based on MgB2 nanobridges
The recently discovered superconductor MgB2, with a transition temperature of
39K, has significant potential for future electronics. An essential step is the
achievement of Josephson circuits, of which the superconducting quantum
interference device (SQUID) is the most important. Here, we report Josephson
quantum interference in superconducting MgB2 thin films. Modulation voltages of
up to 30 microvolt are observed in an all-MgB2 SQUID, based on focused ion beam
patterned nanobridges. These bridges, with a length scale < 100 nm, have
outstanding critical current densities of 7 x 10^6 A/cm2 at 4.2 K.Comment: submitted to Appl. Phys. Let
Mediterranean spotted fever-like illness caused by Rickettsia sibirica mongolitimonae, North Macedonia, June 2022
Mediterranean spotted fever-like illness (MSF-like illness) is a tick-borne disease caused by Rickettsia sibirica mongolitimonae first reported in France more than 25 years ago. Until today, more than 50 cases of MSF-like illness have been reported in different regions of Europe and Africa, highlighting variable clinical manifestation. Here we report a case of MSF-like illness following a bite from a Hyalomma tick in the Skopje region of North Macedonia
- …