914 research outputs found

    INDICATION OF META-ANTHRACITE BY MAGNETOTELLURICS IN THE KƐSZEG-RECHNITZ PENNINIC WINDOW : A TEST AREA

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    One of the Penninic Nappes is the KƑszeg-Rechnitz (K-R) tectonic window at the Eastern end of the Eastern Alps. It has a complicated metamorphic history from the Jurassic time. The organic material of the Penninic Ocean was transformed to electrically conductive meta-anthracite. Its amount in the chalcophyllite is estimated by geochemists to 0.2 per cent. Taking this conducting structure as a test area pilot deep magnetotelluric (MT) soundings have been carried out and we determined - the structure of the conductivity anomaly due to 0.2 per cent meta anthracite in the K-R window and its surroundings - the different kinds of MT distortions as lateral (side) effect of the conductor appearing in the crust and mantle - the most probable depth of the conductive asthenosphere at the border of the Pannonian Basin (having extreme shallow asthenosphere). The obtained ~140 km depth is in correlation with value of the asthenospheric map based mainly on seismic data

    Remote effects in real induction arrows

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    In August 2001, Annali di Geofisica, 44 (4), pp. 659-669, published the paper: «Anomalous directional behaviour of the real parts of the induction arrows in the Eastern Alps: tectonic and palaeogeographic implications» written by Marcus Gurk and Pierre-André Schnegg. Concerning this paper we have two brief comments

    Dynamic control of modern, network-based epidemic models

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    In this paper we make the first steps to bridge the gap between classic control theory and modern, network-based epidemic models. In particular, we apply nonlinear model predictive control (NMPC) to a pairwise ODE model which we use to model a susceptible-infectious-susceptible (SIS) epidemic on nontrivial contact structures. While classic control of epidemics concentrates on aspects such as vaccination, quarantine, and fast diagnosis, our novel setup allows us to deliver control by altering the contact network within the population. Moreover, the ideal outcome of control is to eradicate the disease while keeping the network well connected. The paper gives a thorough and detailed numerical investigation of the impact and interaction of system and control parameters on the controllability of the system. For a certain combination of parameters, we used our method to identify the critical control bounds above which the system is controllable. We foresee that our approach can be extended to even more realistic or simulation-based models with the aim of applying these to real-world situations

    Characteristics of ferroelectric-ferroelastic domains in N{\'e}el-type skyrmion host GaV4_4S8_8

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    GaV4_4S8_8 is a multiferroic semiconductor hosting N{\'e}el-type magnetic skyrmions dressed with electric polarization. At Ts_s = 42K, the compound undergoes a structural phase transition of weakly first-order, from a non-centrosymmetric cubic phase at high temperatures to a polar rhombohedral structure at low temperatures. Below Ts_s, ferroelectric domains are formed with the electric polarization pointing along any of the four <111>\left< 111 \right> axes. Although in this material the size and the shape of the ferroelectric-ferroelastic domains may act as important limiting factors in the formation of the N{\'e}el-type skyrmion lattice emerging below TC_C=13\:K, the characteristics of polar domains in GaV4_4S8_8 have not been studied yet. Here, we report on the inspection of the local-scale ferroelectric domain distribution in rhombohedral GaV4_4S8_8 using low-temperature piezoresponse force microscopy. We observed mechanically and electrically compatible lamellar domain patterns, where the lamellae are aligned parallel to the (100)-type planes with a typical spacing between 100 nm-1.2 Ό\mum. We expect that the control of ferroelectric domain size in polar skyrmion hosts can be exploited for the spatial confinement and manupulation of N{\'e}el-type skyrmions

    FORMATION AND CHARACTERIZATION OF NITROGEN IMPLANTED SILICON-ON-INSULATOR STRUCTURE

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    Silicon wafer has been implanted with 200keV14N+ ions to a dose of 0.75 x 10 18N+ /cm2 at a temperature of 600°C and has been annealed at 1300°C for 2 hours. During post-annealing rapid redistribution of the implanted nitrogen results in formation of buried polycrystalline nitride layer under the damage-free (except for few dislocations < 10⁔/cm2) single crystal silicon layer, which is characterized by n type conduction. The buried dielectric has a resistivity of approximately 10⁞ Ωcm. P channel integrated circuit transistors have been fabricated in the buried nitrid area. The measurements of these transistor devices demonstrate the suitability of nitrogen implanted SOl structure for integrated circuit application

    MOST light-curve analysis of the gamma Dor pulsator HR 8799, showing resonances and amplitude variations

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    Context The central star of the HR 8799 system is a gamma Doradus-type pulsator. The system harbours four planetary-mass companions detected by direct imaging, and is a good solar system analogue. The masses of the companions are not known accurately, because the estimation depends strongly on the age of the system, which is also not known with sufficient accuracy. Asteroseismic studies of the star might help to better constrain the age of HR\,8799. We organized an extensive photometric and multi-site spectroscopic observing campaign for studying the pulsations of the central star. Aims The aim of the present study is to investigate the pulsation properties of HR 8799 in detail via the ultra-precise 47-d-long nearly continuous photometry obtained with the MOST space telescope, and to find as many independent pulsation modes as possible, which is the prerequisite of an asteroseismic age determination. Methods We carried out Fourier analysis of the wide-band photometric time series. Results e find that resonance and sudden amplitude changes characterize the pulsation of HR 8799. The dominant frequency is always at f_1 = 1.978 d^-1. Many multiples of one ninth of the dominant frequency appear in the Fourier spectrum of the MOST data: n/9 f_1, where n = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 14, 17, 18\}. Our analysis also reveals that many of these peaks show strong amplitude decrease and phase variations even on the 47-d time-scale. The dependencies between the pulsation frequencies of HR 8799 make the planned subsequent asteroseismic analysis rather difficult. We point out some resemblance between the light curve of HR 8799 and the modulated pulsation light curves of Blazhko RR Lyrae stars

    Quantum quench in the Luttinger model with finite temperature initial state

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    We study the nonequilibrium dynamics of the Luttinger model after a quantum quench, when the initial state is a finite temperature thermal equilibrium state. The diagonal elements of the density matrix in the steady state show thermal features for high temperature initial states only, otherwise they retain highly nonthermal character. The time evolution of Uhlmann fidelity, which measures the distance between the time evolved and initial states, is evaluated for arbitrary initial temperatures and quench protocols. In the long time limit, the overlap between the time evolved and initial system decreases exponentially with the temperature with a universal prefactor. Within perturbation theory, the statistics of final total energy and work are numerically evaluated in the case of a sudden quench, which yield identical distributions at zero temperature. In both statistics, temperature effects are more significant in small systems. The Dirac-delta peak at the adiabatic ground state energy remains present in the probability distribution of the total energy, but disappears from the work distribution at nonzero initial temperatures

    From Discrete to Continuous and Back: Abstractions and Mesoscopic Phenomena in Cells

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    We discuss the interplay between stochasticity and multistability in bio-molecular networks. The resulting cell-level stochastic behavior reflects the fundamentally discrete and random nature of the underlying molecular processes. These ideas are illustrated on the well studied example of the lac operon. We first describe the switching behavior predicted by a differential-equation based model and then show how cell-level stochastic behavior emerges. Finally we point out that the observed macroscopic behavior may not be enough to determine both the dynamic and stochastic parameters
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