716 research outputs found

    Who guards the guardians of monetary stability and financial stability? That is the key question behind the debate about the accountability of the Bank of England

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    Rosa Lastra unpicks the debate surrounding the accountability of the increasingly powerful Bank of England. She argues that the Bank of England should be made accountable to Parliament, and calls for a better understanding of how we should assess the Bank’s role in creating financial stability

    Entanglement properties in the Inhomogeneous Tavis-Cummings model

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    In this work we study the properties of the atomic entanglement in the eigenstates spectrum of the inhomogeneous Tavis-Cummings Model. The inhomogeneity is present in the coupling among the atoms with quantum electromagnetic field. We calculate analytical expressions for the concurrence and we found that this exhibits a strong dependence on the inhomogeneity.Comment: 5 pages, 5 figure

    Phonon-induced entanglement dynamics of two donor-based charge quantum bits

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    The entanglement dynamics of a pair of donor-based charge qubits is obtained in analytical form. The disentanglement is induced by off resonant scattering of acoustical phonons in the semiconductor host. According to our results a rather unusual recovery of entanglement occurs that depends on the geometrical configuration of the qubits. In addition, for large times a non-vanishing stationary entanglement is predicted. For the cases of one and two initial excitations a simple kinetic interpretation allows for an adequate analysis of the observed dynamics. Our results also reveal a direct relation between the disentanglement rate and the inter-donor decoherence rates

    Towards an analytical description of active microswimmers in clean and in surfactant-covered drops

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    Geometric confinements are frequently encountered in the biological world and strongly affect the stability, topology, and transport properties of active suspensions in viscous flow. Based on a far-field analytical model, the low-Reynolds-number locomotion of a self-propelled microswimmer moving inside a clean viscous drop or a drop covered with a homogeneously distributed surfactant, is theoretically examined. The interfacial viscous stresses induced by the surfactant are described by the well-established Boussinesq-Scriven constitutive rheological model. Moreover, the active agent is represented by a force dipole and the resulting fluid-mediated hydrodynamic couplings between the swimmer and the confining drop are investigated. We find that the presence of the surfactant significantly alters the dynamics of the encapsulated swimmer by enhancing its reorientation. Exact solutions for the velocity images for the Stokeslet and dipolar flow singularities inside the drop are introduced and expressed in terms of infinite series of harmonic components. Our results offer useful insights into guiding principles for the control of confined active matter systems and support the objective of utilizing synthetic microswimmers to drive drops for targeted drug delivery applications.Comment: 19 pages, 7 figures. Regular article contributed to the Topical Issue of the European Physical Journal E entitled "Physics of Motile Active Matter" edited by Gerhard Gompper, Clemens Bechinger, Holger Stark, and Roland G. Winkle

    A first step to accelerating fingerprint matching based on deformable minutiae clustering

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    Fingerprint recognition is one of the most used biometric methods for authentication. The identification of a query fingerprint requires matching its minutiae against every minutiae of all the fingerprints of the database. The state-of-the-art matching algorithms are costly, from a computational point of view, and inefficient on large datasets. In this work, we include faster methods to accelerating DMC (the most accurate fingerprint matching algorithm based only on minutiae). In particular, we translate into C++ the functions of the algorithm which represent the most costly tasks of the code; we create a library with the new code and we link the library to the original C# code using a CLR Class Library project by means of a C++/CLI Wrapper. Our solution re-implements critical functions, e.g., the bit population count including a fast C++ PopCount library and the use of the squared Euclidean distance for calculating the minutiae neighborhood. The experimental results show a significant reduction of the execution time in the optimized functions of the matching algorithm. Finally, a novel approach to improve the matching algorithm, considering cache memory blocking and parallel data processing, is presented as future work.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Quantum recoil effects in finite-time disentanglement of two distinguishable atoms

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    Starting from the requirement of distinguishability of two atoms by their positions, it is shown that photon recoil has a strong influence on finite-time disentanglement and in some cases prevents its appearance. At near-field inter atomic distances well localized atoms, with maximally one atom being initially excited, may suffer disentanglement at a single finite time or even at a series of equidistant finite times, depending on their mean inter atomic distance and their initial electronic preparation.Comment: 13 pages, 1 figure, submitted to Physical Review on august 2

    Web based system architecture for long pulse remote experimentation

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    Remote experimentation (RE) methods will be essential in next generation fusion devices. Requirements for long pulse RE will be: on-line data visualization, on-line data acquisition processes monitoring and on-line data acquisition systems interactions (start, stop or set-up modifications). Note that these methods are not oriented to real-time control of fusion plant devices. INDRA Sistemas S.A., CIEMAT (Centro de Investigaciones Energéticas Medioambientales y Tecnológicas) and UPM (Universidad Politécnica de Madrid) have designed a specific software architecture for these purposes. The architecture can be supported on the BeansNet platform, whose integration with an application server provides an adequate solution to the requirements. BeansNet is a JINI based framework developed by INDRA, which makes easy the implementation of a remote experimentation model based on a Service Oriented Architecture. The new software architecture has been designed on the basis of the experience acquired in the development of an upgrade of the TJ-II remote experimentation system

    Efectos del tráfico del tractor sobre la distribución de la compactación del suelo y los rendimientos de trigo en España

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    395-403The general objective of this paper was to quantify the changes in the physical properties of an Aridisol soil and the effect on wheat yield due to agricultural tractors traffic in the Vélez Blanco District, Almería Spain. Parameters measured were cone index (CI) in the 0-600 mm depth profile, bulk density (BD) and rut depth; the variable wheat yields (WY) was measured too. The traffic treatments applied were: 0 (control plot), 1, 3, 5, and 7 tractor passes in the same tracks. Each experimental plot was trafficked with two tractors, one light (60 kN) and one heavy (80 kN). In topsoil (0-200 mm), up to five passes of the heavy (HT) and light tractors (LT), as in one and three passes, the BD and CI values responded to the ground pressure being higher in absolute value for LT. For the 200 to 400 mm depth range HT caused higher CI (1,570 to 2,200 kPa) and BD (1.38 to 1.68 Mg m-3) values than LT. Eight months later, WY was evaluated in tractor's track areas and decreases in the range of 18-38 percent, were measured. For seven passes the applications of total loads of 80 and 60 kN increased BD up to 1.5 Mg m-3 at depths of 200-600 mm. Although soil had high bulk density prior to traffic treatments, a significant increment of subsoil compaction still occurred due to the high traffic intensities applied

    Calculation of quantum discord for qubit-qudit or N qubits

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    Quantum discord, a kind of quantum correlation, is defined as the difference between quantum mutual information and classical correlation in a bipartite system. It has been discussed so far for small systems with only a few independent parameters. We extend here to a much broader class of states when the second party is of arbitrary dimension d, so long as the first, measured, party is a qubit. We present two formulae to calculate quantum discord, the first relating to the original entropic definition and the second to a recently proposed geometric distance measure which leads to an analytical formulation. The tracing over the qubit in the entropic calculation is reduced to a very simple prescription. And, when the d-dimensional system is a so-called X state, the density matrix having non-zero elements only along the diagonal and anti-diagonal so as to appear visually like the letter X, the entropic calculation can be carried out analytically. Such states of the full bipartite qubit-qudit system may be named "extended X states", whose density matrix is built of four block matrices, each visually appearing as an X. The optimization involved in the entropic calculation is generally over two parameters, reducing to one for many cases, and avoided altogether for an overwhelmingly large set of density matrices as our numerical investigations demonstrate. Our results also apply to states of a N-qubit system, where "extended X states" consist of (2^(N+2) - 1) states, larger in number than the (2^(N+1) - 1) of X states of N qubits. While these are still smaller than the total number (2^(2N) - 1) of states of N qubits, the number of parameters involved is nevertheless large. In the case of N = 2, they encompass the entire 15-dimensional parameter space, that is, the extended X states for N = 2 represent the full qubit-qubit system.Comment: 6 pages, 1 figur

    An adaptation of meaning-centered psychotherapy integrating "essential care": A pilot study

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    Introduction There is a growing interest in the emotional state of cancer patients. The main objective of this pilot study is to assess the feasibility, acceptability, and preliminary efficacy of Meaning-Centered Psychotherapy and Essential Care (MCP-EC) in patients with advanced cancer compared with usual psychological support. We define "Essential Care"as the promotion of patient care and self-care through the recall of good care experiences and discussion of the concepts: responsibility, self-compassion, kindness, and attitude. Method Pilot, single-center, and prospective study of 30 patients with advanced cancer and emotional distress. Our adaptation consisted in three session Meaning-Centered Psychotherapy-Palliative Care, plus a fourth session named "Essential Care". The study was carried out in two phases. First, 20 patients were randomized to one of the two arms: individual MCP-EC (experimental, n = 10) or usual psychological supportive (control, n = 10). In a second phase, 10 patients were assigned consecutively to Group MCP-EC (n = 10). All patients were evaluated at baseline (pre-) and post-intervention with questionnaires for sociodemographic data and clinical scales. Results Nineteen patients completed the 4 sessions of MCP-EC, 9 individual format and 10 group format. Usual supportive intervention was delivered to 10 control patients. Total 28 patients completed pre- and post-treatment evaluations. There were no pre- vs. post-differences in the evaluations of the control group. In the experimental group, significant pre- vs. post-differences were found in EQ-5D-3L, HADS, FACIT, DM, HAI, SCS-SF, and TD questionnaires. These results indicated that MCP-EC reduced anxiety and depression symptoms, hopelessness, demoralization, as well as increased spiritual well-being and sense of meaning. Participants were satisfied and found the MCP-EC intervention positively. Conclusions This pilot study suggests that the MCP-EC has feasibility, acceptability, and preliminary efficacy reducing the emotional distress in advanced cancer patients. Larger studies are warranted to clarify the strengths and limitations of this psychotherapy. © The Author(s), 2021. Published by Cambridge University Press
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