19,775 research outputs found
Capturing asymmetry in real exchange rate with quantile autoregression
Quantile autoregression is used to explore asymmetries in the adjustment process of pair wise real exchange rate between the Italian lire, French franc, Deutsch mark, and the British pound. Based on the best specification for each quantile we construct predicted conditional density functions which guided us to identify two sources of asymmetry: 1) dispersion depends on the conditioned value of the real exchange rate, i.e., “conditional” heterokedasticity; 2) the probability of increases and falls also changes according to the conditioned value, i.e., there is higher probability for the real exchange rate to appreciate (depreciate) given the currency is depreciated (appreciated).We only verified strong heterokedasticity in relations among the lire, franc, and mark, which was resolved by estimating quadratic autoregressive model for some quantiles. Relations involving the pound presented stable but higher dispersion indicating larger probability of wider oscillation.exchange rate; quantile autoregression; unit root; asymmetry
Sublattice asymmetry of impurity doping in graphene: A review
In this review we highlight recent theoretical and experimental work on
sublattice asymmetric doping of impurities in graphene, with a focus on
substitutional Nitrogen dopants. It is well known that one current limitation
of graphene in regards to its use in electronics is that in its ordinary state
it exhibits no band gap. By doping one of its two sublattices preferentially it
is possible to not only open such a gap, which can furthermore be tuned through
control of the dopant concentration, but in theory produce quasi-ballistic
transport of electrons in the undoped sublattice, both important qualities for
any graphene device to be used competetively in future technology. We outline
current experimental techniques for synthesis of such graphene monolayers and
detail theoretical efforts to explain the mechanisms responsible for the
effect, before suggesting future research directions in this nascent field.Comment: 20 pages, 4 figures. Accepted for publication in Beilstein Journal of
Nanotechnolog
Narrowband delay tolerant protocols for WSN applications. Characterization and selection guide
This article focuses on delay tolerant protocols for Wireless Sensor Network (WSN) applications, considering both established and new protocols. We obtained a comparison of their characteristics by implementing all of them on an original platform for network simulation, and by testing their behavior on a common test-bench. Thereafter, matching the requirements linked to each application with the performances achieved in the test-bench, allowed us to define an application oriented protocol selection guide
Majorana and the theoretical problem of photon-electron scattering
Relevant contributions by Majorana regarding Compton scattering off free or
bound electrons are considered in detail, where a (full quantum) generalization
of the Kramers-Heisenberg dispersion formula is derived. The role of
intermediate electronic states is appropriately pointed out in recovering the
standard Klein-Nishina formula (for free electron scattering) by making
recourse to a limpid physical scheme alternative to the (then unknown) Feynman
diagram approach. For bound electron scattering, a quantitative description of
the broadening of the Compton line was obtained for the first time by
introducing a finite mean life for the excited state of the electron system.
Finally, a generalization aimed to describe Compton scattering assisted by a
non-vanishing applied magnetic field is as well considered, revealing its
relevance for present day research.Comment: latex, amsart, 10 pages, 1 figur
SZ contribution to characterize the shape of galaxy cluster haloes
We present the on-going activity to characterize the geometrical properties of the gas and dark matter haloes using multi-wavelength observations of galaxy clusters. The role of the SZ signal in describing the gas distribution is discussed for the pilot case of the CLASH object MACS J1206.2-0847
Simulation of instability at transition energy with a new impedance model for CERN PS
Instabilities driven by the transverse impedance are proven to be one of the limitations for the high intensity reach of the CERN PS. Since several years, fast single bunch vertical instability at transition energy has been observed with the high intensity bunch serving the neutron Time-of-Flight facility (n-ToF). In order to better understand the instability mechanism, a dedicated measurement campaign took place. The results were compared with macro-particle simulations with PyHEADTAIL based on the new impedance model developed for the PS. Instability threshold and growth rate for different longitudinal emittances and beam intensities were studied
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