3,637 research outputs found
Fractional dynamics in the L\'evy quantum kicked rotor
We investigate the quantum kicked rotor in resonance subjected to momentum
measurements with a L\'evy waiting time distribution. We find that the system
has a sub-ballistic behavior. We obtain an analytical expression for the
exponent of the power law of the variance as a function of the characteristic
parameter of the L\'evy distribution and connect this anomalous diffusion with
a fractional dynamics
Gender in endocrine diseases: role of sex gonadal hormones
Gender- and sex- related differences represent a new frontier towards patient-tailored medicine, taking into account that
theoretically every medical specialty can be influenced by both of them. Sex hormones define the differences between
males and females, and the different endocrine environment promoted by estrogens, progesterone, testosterone, and their
precursors might influence both human physiology and pathophysiology. With the term Gender we refer, instead, to behaviors,
roles, expectations, and activities carried out by the individual in society. In other words, “gender” refers to a sociocultural
sphere of the individual, whereas “sex” only defines the biological sex. In the last decade, increasing attention has been paid to
understand the influence that gender can have on both the human physiology and pathogenesis of diseases. Even the clinical
response to therapy may be influenced by sex hormones and gender, but further research is needed to investigate and clarify
how they can affect the human pathophysiology. The path to a tailored medicine in which every patient is able to receive early
diagnosis, risk assessments, and optimal treatments cannot exclude the importance of gender. In this review, we have focused
our attention on the involvement of sex hormones and gender on different endocrine diseases
The sentiment analysis of tweets as a new tool to measure public perception of male erectile and ejaculatory dysfunctions
Twitter is a social network based on "tweets," short messages of up to 280 characters. Social media has been investigated in health care research to ascertain positive or negative feelings associated with several conditions but never in sexual medicin
Effect of current corrugations on the stability of the tearing mode
The generation of zonal magnetic fields in laboratory fusion plasmas is
predicted by theoretical and numerical models and was recently observed
experimentally. It is shown that the modification of the current density
gradient associated with such corrugations can significantly affect the
stability of the tearing mode. A simple scaling law is derived that predicts
the impact of small stationary current corrugations on the stability parameter
. The described destabilization mechanism can provide an explanation
for the trigger of the Neoclassical Tearing Mode (NTM) in plasmas without
significant MHD activity.Comment: Accepted to Physics of Plasma
Tsunami excitation by inland/coastal earthquakes: the Green function approach
International audienceIn the framework of the linear theory, the representation theorem is derived for an incompressible liquid layer with a boundary of arbitrary shape and in a homogeneous gravity field. In addition, the asymptotic representation for the Green function, in a layer of constant thickness is obtained. The validity of the approach for the calculation of the tsunami wavefield based on the Green function technique is verified comparing the results with those obtained from the modal theory, for a liquid layer of infinite horizontal dimensions. The Green function approach is preferable for the estimation of the excitation spectra, since in the case of an infinite liquid layer it leads to simple analytical expressions. From this analysis it is easy to describe the peculiarities of tsunami excitation by different sources. The method is extended to the excitation of tsunami in a semiinfinite layer with a sloping boundary. Numerical modelling of the tsunami wavefield, excited by point sources at different distances from the coastline, shows that when the source is located at a distance from the coastline equal or larger than the source depth, the shore presence does not affect the excitation of the tsunami. When the source is moved towards thecoastline, the low frequency content in the excitation spectrum ecreases, while the high frequencies content increases dramatically. The maximum of the excitation spectra from inland sources, located at a distance from the shore like the source depth, becomes less than 10% of that radiated if the same source is located in the open ocean. The effect of the finiteness of the source is also studied and the excitation spectrum is obtained by integration over the fault area. Numerical modelling of the excitation spectra for different source models shows that, for a given seismic moment, the spectral level, as well as the maximum value of the spectra, decreases with increasing fault size. When the sources are located in the vicinity of a shore, the synthetic mareograms calculated at distances greater than the source depth show that the maximum tsunami amplitude decays with decreasing source-to-shore distance. The rate of decay is dependent on the dip, length and depth of the fault. The tsunami intensity, defined as maximum peak-to-peak amplitude, decays with the inland distance of the source from the coast. At an inland distance equal to the source depth, it becomes 4?5 times less than that from a source in the open ocean. If the source is located under the coastline, the intensity of tsunami is approximately the same as for oceanic sources
Decoherent quantum walks driven by a generic coin operation
We consider the effect of different unitary noise mechanisms on the evolution
of a quantum walk (QW) on a linear chain with a generic coin operation: (i)
bit-flip channel noise, restricted to the coin subspace of the QW, and (ii)
topological noise caused by randomly broken links in the linear chain.
Similarities and differences in the respective decoherent dynamics of the
walker as a function of the probability per unit time of a decoherent event
taking place are discussed
Lateral variation of crust and upper mantle structures in NW Iran derived from surface wave analysis
To obtain the shear velocity structure across North-West of Iran and surrounding areas to a depth of 160 km, we performed a namely Hedgehog nonlinear inversion on Rayleigh wave group velocity dispersion curves in the period range from 7 to 60 s. The distributed dispersion curves are the results of our surface waves dispersion tomography using the data of 280 local and regional seismic events, recorded by the medium and broad band seismic stations in the region. We outline different crust and upper mantle structures for the study area based on calculated group and shear velocities. Our results reveal relatively low velocities at the shorter periods (7 - 10 s) in the presence of sedimentary basins (e.g. South Caspian Basin) and for eastern Anatolia and relatively high velocities along the Sanandaj-Sirjan Metamorphic zone, Alborz, Talesh and the Lesser Caucasus Mountains. By depth inversion of group velocities, we observed a 14 km thick sediments in South Caspian Basin and Kura Depression. Based on our maps at 20 s, we outline different crustal models for the region and highlight the differences between South Caspian Basin and NW Iran, on one side, and the similarities between the South Caspian Basin and Kura Depression, that extend beneath Talesh, Alborz and Lesser Caucasus, on the other. Comparing the shear velocity of lower crust in South Caspian Basin and Kura Depression with that of NW Iran proves different origination of lower crust in the basin, probably oceanic source, because of its significant higher shear velocity rather than NW Iran. The extension of lower crust beneath Talesh is more than middle crust while in Alborz and Lesser Caucasus the amount of extension for middle and lower crust is the same The analysis of group velocities at longer periods ( 65 35 s) and obtained shear velocity models allows us to outline different lithospheric structures and crustal depth in the region. The high group velocities in Talesh, South Caspian Sea and Lesser Caucasus on one side and Zagros Folding and Thrust Belt on the other, beside the result of shear velocity models suggest the presence of a stable and thick mantle lid that seems to be thin or absent in the eastern Anatolia and much of NW Iran. The shallowest Moho and Lithosphere Asthenosphere boundary depth of 37 and 63 km, were observed in Easter Anatolian Accretionary Complex. The thin mantle lid in this region has affected the whole crust in such a way that we observed the lowest shear velocities inside the crust in this region. We observed a significant thickening of both crust and lithosphere in Sanandaj-Sirjan Metamorphic zone comparing to Urmieh Dokhtar Magmatic Arc and Zagros Folding and Thrust Belt on its two sides
Overview of the JET results
Since the installation of an ITER-like wall, the JET programme has focused on the consolidation of ITER design choices and the preparation for ITER operation, with a specific emphasis given to the bulk tungsten melt experiment, which has been crucial for the final decision on the material choice for the day-one tungsten divertor in ITER. Integrated scenarios have been progressed with the re-establishment of long-pulse, high-confinement H-modes by optimizing the magnetic configuration and the use of ICRH to avoid tungsten impurity accumulation. Stationary discharges with detached divertor conditions and small edge localized modes have been demonstrated by nitrogen seeding. The differences in confinement and pedestal behaviour before and after the ITER-like wall installation have been better characterized towards the development of high fusion yield scenarios in DT. Post-mortem analyses of the plasma-facing components have confirmed the previously reported low fuel retention obtained by gas balance and shown that the pattern of deposition within the divertor has changed significantly with respect to the JET carbon wall campaigns due to the absence of thermally activated chemical erosion of beryllium in contrast to carbon. Transport to remote areas is almost absent and two orders of magnitude less material is found in the divertor
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