1,859 research outputs found

    Potential Benefits of the Jesuit Examen for Psychological Health and Well Being: A Pilot Study

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    The Jesuit Examen is a form of prayerful reflection on daily experiences that was introduced five centuries ago by St. Ignatius of Loyola, founder of the Society of Jesus (better known as the Jesuits). The Examen may be utilized by diverse populations when adapted and secularized, which can be completed by substituting the language of God in the original Examen for more inclusive terms such as “love.” Although five centuries old, the 10–15-min daily reflective practice has not been subject to empirical research. Furthermore, research has not explored the effects of the Examen on psychological health and well-being in a workplace setting. Other religious practices, including mindfulness and yoga, are important and religiously derived but now secularized interventions that can be utilized in multiple work and other settings. The present pilot study focused on the potential effectiveness of using a secularized version of the Examen in the workplace to determine whether this practice can produce psychological and well-being health benefits, such as stress reduction and improvement in one’s satisfaction with life

    Learning Implicitly with Noisy Data in Linear Arithmetic

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    Probing two topological surface bands of Sb2Te3 by spin-polarized photoemission spectroscopy

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    Using high resolution spin- and angle-resolved photoemission spectroscopy, we map the electronic structure and spin texture of the surface states of the topological insulator Sb2Te3. In combination with density functional calculations (DFT), we directly show that Sb2Te3 exhibits a partially occupied, single spin-Dirac cone around the Fermi energy, which is topologically protected. DFT obtains a spin polarization of the occupied Dirac cone states of 80-90%, which is in reasonable agreement with the experimental data after careful background subtraction. Furthermore, we observe a strongly spin-orbit split surface band at lower energy. This state is found at 0.8eV below the Fermi level at the gamma-point, disperses upwards, and disappears at about 0.4eV below the Fermi level into two different bulk bands. Along the gamma-K direction, the band is located within a spin-orbit gap. According to an argument given by Pendry and Gurman in 1975, such a gap must contain a surface state, if it is located away from the high symmetry points of the Brillouin zone. Thus, the novel spin-split state is protected by symmetry, too.Comment: 8 pages, 10 figure

    QPCR: Application for real-time PCR data management and analysis

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    BACKGROUND: Since its introduction quantitative real-time polymerase chain reaction (qPCR) has become the standard method for quantification of gene expression. Its high sensitivity, large dynamic range, and accuracy led to the development of numerous applications with an increasing number of samples to be analyzed. Data analysis consists of a number of steps, which have to be carried out in several different applications. Currently, no single tool is available which incorporates storage, management, and multiple methods covering the complete analysis pipeline. RESULTS: QPCR is a versatile web-based Java application that allows to store, manage, and analyze data from relative quantification qPCR experiments. It comprises a parser to import generated data from qPCR instruments and includes a variety of analysis methods to calculate cycle-threshold and amplification efficiency values. The analysis pipeline includes technical and biological replicate handling, incorporation of sample or gene specific efficiency, normalization using single or multiple reference genes, inter-run calibration, and fold change calculation. Moreover, the application supports assessment of error propagation throughout all analysis steps and allows conducting statistical tests on biological replicates. Results can be visualized in customizable charts and exported for further investigation. CONCLUSION: We have developed a web-based system designed to enhance and facilitate the analysis of qPCR experiments. It covers the complete analysis workflow combining parsing, analysis, and generation of charts into one single application. The system is freely available a

    Photoemission of Bi2_2Se3_3 with Circularly Polarized Light: Probe of Spin Polarization or Means for Spin Manipulation?

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    Topological insulators are characterized by Dirac cone surface states with electron spins aligned in the surface plane and perpendicular to their momenta. Recent theoretical and experimental work implied that this specific spin texture should enable control of photoelectron spins by circularly polarized light. However, these reports questioned the so far accepted interpretation of spin-resolved photoelectron spectroscopy. We solve this puzzle and show that vacuum ultraviolet photons (50-70 eV) with linear or circular polarization probe indeed the initial state spin texture of Bi2_2Se3_3 while circularly polarized 6 eV low energy photons flip the electron spins out of plane and reverse their spin polarization. Our photoemission calculations, considering the interplay between the varying probing depth, dipole selection rules and spin-dependent scattering effects involving initial and final states explain these findings, and reveal proper conditions for light-induced spin manipulation. This paves the way for future applications of topological insulators in opto-spintronic devices.Comment: Submitted for publication (2013

    Properties of continuous Fourier extension of the discrete cosine transform and its multidimensional generalization

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    A versatile method is described for the practical computation of the discrete Fourier transforms (DFT) of a continuous function g(t)g(t) given by its values gjg_{j} at the points of a uniform grid FNF_{N} generated by conjugacy classes of elements of finite adjoint order NN in the fundamental region FF of compact semisimple Lie groups. The present implementation of the method is for the groups SU(2), when FF is reduced to a one-dimensional segment, and for SU(2)×...×SU(2)SU(2)\times ... \times SU(2) in multidimensional cases. This simplest case turns out to result in a transform known as discrete cosine transform (DCT), which is often considered to be simply a specific type of the standard DFT. Here we show that the DCT is very different from the standard DFT when the properties of the continuous extensions of these two discrete transforms from the discrete grid points tj;j=0,1,...Nt_j; j=0,1, ... N to all points tFt \in F are considered. (A) Unlike the continuous extension of the DFT, the continuous extension of (the inverse) DCT, called CEDCT, closely approximates g(t)g(t) between the grid points tjt_j. (B) For increasing NN, the derivative of CEDCT converges to the derivative of g(t)g(t). And (C), for CEDCT the principle of locality is valid. Finally, we use the continuous extension of 2-dimensional DCT to illustrate its potential for interpolation, as well as for the data compression of 2D images.Comment: submitted to JMP on April 3, 2003; still waiting for the referee's Repor

    Generalized iterated wreath products of cyclic groups and rooted trees correspondence

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    Consider the generalized iterated wreath product Zr1Zr2Zrk\mathbb{Z}_{r_1}\wr \mathbb{Z}_{r_2}\wr \ldots \wr \mathbb{Z}_{r_k} where riNr_i \in \mathbb{N}. We prove that the irreducible representations for this class of groups are indexed by a certain type of rooted trees. This provides a Bratteli diagram for the generalized iterated wreath product, a simple recursion formula for the number of irreducible representations, and a strategy to calculate the dimension of each irreducible representation. We calculate explicitly fast Fourier transforms (FFT) for this class of groups, giving literature's fastest FFT upper bound estimate.Comment: 15 pages, to appear in Advances in the Mathematical Science

    Topological surface state under graphene for two-dimensional spintronics in air

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    Spin currents which allow for a dissipationless transport of information can be generated by electric fields in semiconductor heterostructures in the presence of a Rashba-type spin-orbit coupling. The largest Rashba effects occur for electronic surface states of metals but these cannot exist but under ultrahigh vacuum conditions. Here, we reveal a giant Rashba effect ({\alpha}_R ~ 1.5E-10 eVm) on a surface state of Ir(111). We demonstrate that its spin splitting and spin polarization remain unaffected when Ir is covered with graphene. The graphene protection is, in turn, sufficient for the spin-split surface state to survive in ambient atmosphere. We discuss this result along with evidences for a topological protection of the surface state.Comment: includes supplementary informatio
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