6,641 research outputs found

    Use of Mental Imagery in Psychotherapy: A Critical Review

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    The paper presents arguments in favor of the use of mental imagery for therapeutic purposes. Several existing imagery approaches to psychotherapy are critically examined and suggestions for future inquiry are offered. The intimate relation between imagery and the affective-somatic processes is stressed

    Modelling the variable broad-band optical/UV/X-ray spectrum of PG1211+143: Implications for the ionized outflow

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    We present the results from a detailed analysis of the 2007 Swift monitoring campaign of the quasar PG1211+143. We constructed broad-band, optical/UV/X-ray spectral energy distributions over three X-ray flux intervals. We fitted them with a model which accounts for the disc and the X-ray coronal emission and the warm absorber (well established in this source). The three flux spectra are well fitted by the model we considered. The disc inner temperature remains constant at ~2 eV, while X-rays are variable both in spectral slope and normalization. The absorber covers almost 90% of the central source. It is outflowing with a velocity less than 2.3*10^4 km/s (3sigma upper limit), and has a column density of ~10^23.2. Its ionization parameter varies by a factor of 1.6, and it is in photo-ionizing equilibrium with the ionizing flux. It is located at a distance of less than 0.35 pc from the central source and its relative thickness, DR/R is less than 0.1. The absorber' s ionization parameter variations can explain the larger than average amplitude of the X-ray variations. The absence of optical/UV variations (consistent with the high black hole mass estimate) argues against the presence of inward propagating disc fluctuations and strong X-ray illumination of the disc (in agreement with the low ratio of X-ray over the bolometric luminosity of ~20-35). We estimate an upper limit for the mass outflow of ~5 solar masses per year (~2.3 times the Eddington mass accretion rate). If the outflow rate is indeed that high, then it must be a short-lived episode in the quasar's life time. Finally, we estimate an upper limit for the kinetic power of the outflow of ~1.4*10^43 ergs/s. This outflow cannot deploy significant mechanical energy to the surrounding ISM of the quasar's host galaxy, but is sufficient to heat the ISM to 10^7 K and to produce a fast decline to the star formation rate of the galaxy.Comment: Accepted for publication by A&

    A study of the entanglement in systems with periodic boundary conditions

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    We define the local periodic linking number, LK, between two oriented closed or open chains in a system with three-dimensional periodic boundary conditions. The properties of LK indicate that it is an appropriate measure of entanglement between a collection of chains in a periodic system. Using this measure of linking to assess the extent of entanglement in a polymer melt we study the effect of CReTA algorithm on the entanglement of polyethylene chains. Our numerical results show that the statistics of the local periodic linking number observed for polymer melts before and after the application of CReTA are the same.Comment: 11 pages, 11 figure

    On the push&pull protocol for rumour spreading

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    The asynchronous push&pull protocol, a randomized distributed algorithm for spreading a rumour in a graph GG, works as follows. Independent Poisson clocks of rate 1 are associated with the vertices of GG. Initially, one vertex of GG knows the rumour. Whenever the clock of a vertex xx rings, it calls a random neighbour yy: if xx knows the rumour and yy does not, then xx tells yy the rumour (a push operation), and if xx does not know the rumour and yy knows it, yy tells xx the rumour (a pull operation). The average spread time of GG is the expected time it takes for all vertices to know the rumour, and the guaranteed spread time of GG is the smallest time tt such that with probability at least 11/n1-1/n, after time tt all vertices know the rumour. The synchronous variant of this protocol, in which each clock rings precisely at times 1,2,1,2,\dots, has been studied extensively. We prove the following results for any nn-vertex graph: In either version, the average spread time is at most linear even if only the pull operation is used, and the guaranteed spread time is within a logarithmic factor of the average spread time, so it is O(nlogn)O(n\log n). In the asynchronous version, both the average and guaranteed spread times are Ω(logn)\Omega(\log n). We give examples of graphs illustrating that these bounds are best possible up to constant factors. We also prove theoretical relationships between the guaranteed spread times in the two versions. Firstly, in all graphs the guaranteed spread time in the asynchronous version is within an O(logn)O(\log n) factor of that in the synchronous version, and this is tight. Next, we find examples of graphs whose asynchronous spread times are logarithmic, but the synchronous versions are polynomially large. Finally, we show for any graph that the ratio of the synchronous spread time to the asynchronous spread time is O(n2/3)O(n^{2/3}).Comment: 25 page

    The Image and The Unconscious

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    Verbal language has long been the most widely used source of data for clinical inference; recently, however, an increasing number of therapists have turned to images for both diagnostic and therapeutic purposes. This paper focusses upon the use of mental imagery in analytically oriented therapies. The first segment presents a brief discussion of some important psycholinguistic questions that bear upon the use of images in psychotherapy. The second part discusses the observations of spontaneous images by analytical therapists and shows the relation of these images to linguistic-rational cognition and to unconscious organization. The third section brings out the unique function of certain images as symbols containing a wealth of affect-laden material and the fourth portion illustrates the potency of these primarily visual symbols with the work of several depth-therapists who have made extensive use of induced imagery

    Model of Centauro and strangelet production in heavy ion collisions

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    We discuss the phenomenological model of Centauro event production in relativistic nucleus-nucleus collisions. This model makes quantitative predictions for kinematic observables, baryon number and mass of the Centauro fireball and its decay products. Centauros decay mainly to nucleons, strange hyperons and possibly strangelets. Simulations of Centauro events for the CASTOR detector in Pb-Pb collisions at LHC energies are performed. The signatures of these events are discussed in detail.Comment: 19 pages, LaTeX+revtex4, 14 eps-figures and 3 table

    Genetic Algorithms in Antennas and Smart Antennas Design Overview: Two Novel Antenna Systems for Triband GNSS Applications and a Circular Switched Parasitic Array for WiMax Applications Developments with the Use of Genetic Algorithms

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    Genetic algorithms belong to a stochastic class of evolutionary techniques, whose robustness and global search of the solutions space have made them extremely popular among researchers. They have been successfully applied to electromagnetic optimization, including antenna design as well as smart antennas design. In this paper, extensive reference to literature related antenna design efforts employing genetic algorithms is taking place and subsequently, three novel antenna systems are designed in order to provide realistic implementations of a genetic algorithm. Two novel antenna systems are presented to cover the new GPS/Galileo band, namely, L5 (1176 MHz), together with the L1 GPS/Galileo and L2 GPS bands (1575 and 1227 MHz). The first system is a modified PIFA and the second one is a helical antenna above a ground plane. Both systems exhibit enhanced performance characteristics, such as sufficient front gain, input impedance matching, and increased front-to-back ratio. The last antenna system is a five-element switched parasitic array with a directional beam with sufficient beamwidth to a predetermined direction and an adequate impedance bandwidth which can be used as receiver for WiMax signals
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