472 research outputs found

    Evidence that process simulations reduce anxiety in patients receiving dental treatment: randomized exploratory trial

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    Process simulations – mental simulations that ask people to imagine the process of completing a task – have been shown to decrease anxiety in students facing hypothetical or psychological threats in the short term. The aim of the present study was to see whether process simulations could reduce anxiety in a sample of the general population attending a dental practice, and whether these effects could be sustained throughout treatment. Participants (N = 75) were randomized to an experimental condition where they were asked to simulate mentally the process of seeing the dentist, or to a control condition where they were asked to simulate mentally the outcome of seeing the dentist. Findings showed that participants in the experimental condition were significantly less anxious both before and after their consultations. Self-efficacy and self-esteem remained unchanged. This study suggests that process simulation is one active ingredient in anxiety treatment programs and further research is required to enhance its effects

    Fermion Condensates of massless QED2QED_2 at Finite Density in non-trivial Topological Sectors

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    Vacuum expectation values of products of local bilinears ψˉψ\bar\psi\psi are computed in massless QED2QED_2 at finite density. It is shown that chiral condensates exhibit an oscillatory inhomogeneous behaviour depending on the chemical potential. The use of a path-integral approach clarifies the connection of this phenomenon with the topological structure of the theory.Comment: 16 pages, no figures, To be published in Phys.Rev.

    Electromagnetic probes of dense matter in heavy-ion collisions

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    Dilepton and photon production in heavy-ion collisions at SPS energies are studied in the relativistic transport model that incorporates self-consistently the change of hadron masses in dense matter. It is found that the dilepton spectra in proton-nucleus reactions can be well described by the conventional mechanism of Dalitz decay and direct vector meson decay. However, to provide a quantitative explanation of the observed dilepton spectra in central heavy-ion collisions requires contributions other than these direct decays and also various medium effects. Introducing a decrease of vector meson masses in hot dense medium, we find that these heavy-ion data can be satisfactorily explained. Furthermore, the single photon spectra in our calculations with either free or in-medium meson masses do not exceed the upper bound deduced from the experiments by the WA80 Collaboration.Comment: 8 pages, including 4 postscript figures. Talk presented at Sixth International Conference on Nucleus-Nucleus Collisions (NN97), Gatlinburg, June, 1997, to appear in the proceeding

    Managing phase purities and crystal orientation for high-performance and photostable cesium lead halide perovskite solar cells

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    Inorganic perovskites with cesium (Cs+) as the cation have great potential as photovoltaic materials if their phase purity and stability can be addressed. Herein, a series of inorganic perovskites is studied, and it is found that the power conversion efficiency of solar cells with compositions CsPbI1.8Br1.2, CsPbI2.0Br1.0, and CsPbI2.2Br0.8 exhibits a high dependence on the initial annealing step that is found to significantly affect the crystallization and texture behavior of the final perovskite film. At its optimized annealing temperature, CsPbI1.8Br1.2 exhibits a pure orthorhombic phase and only one crystal orientation of the (110) plane. Consequently, this allows for the best efficiency of up to 14.6% and the longest operational lifetime, T S80, of ≈300 h, averaged of over six solar cells, during the maximum power point tracking measurement under continuous light illumination and nitrogen atmosphere. This work provides essential progress on the enhancement of photovoltaic performance and stability of CsPbI3 − x Brx perovskite solar cells

    The foot in forensic human identification - a review

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    The identification of human remains is a process which can be attempted irrespective of the stage of decomposition in which the remains are found or the anatomical regions recovered. In recent years, the discovery of fragmented human remains has garnered significant attention from the national and international media, particularly the recovery of multiple lower limbs and feet from coastlines in North America. While cases such as these stimulate public curiosity, they present unique challenges to forensic practitioners in relation to the identification of the individual from whom the body part originated. There is a paucity of literature pertaining to the foot in forensic human identification and in particular, in relation to the assessment of the parameters represented by the biological profile. This article presents a review of the literature relating to the role of the foot in forensic human identification and highlights the areas in which greater research is required. © 2013

    Hadronic observables from SIS to SPS energies - anything strange with strangeness ?

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    We calculate p,π±,K±p, \pi^\pm, K^\pm and Λ\Lambda(+Σ0\Sigma^0) rapidity distributions and compare to experimental data from SIS to SPS energies within the UrQMD and HSD transport approaches that are both based on string, quark, diquark (q,qˉ,qq,qˉqˉq, \bar{q}, qq, \bar{q}\bar{q}) and hadronic degrees of freedom. The two transport models do not include any explicit phase transition to a quark-gluon plasma (QGP). It is found that both approaches agree rather well with each other and with the experimental rapidity distributions for protons, Λ\Lambda's, π±\pi^\pm and K±K^\pm. Inspite of this apparent agreement both transport models fail to reproduce the maximum in the excitation function for the ratio K+/π+K^+/\pi^+ found experimentally between 11 and 40 A\cdotGeV. A comparison to the various experimental data shows that this 'failure' is dominantly due to an insufficient description of pion rapidity distributions rather than missing 'strangeness'. The modest differences in the transport model results -- on the other hand -- can be attributed to different implementations of string formation and fragmentation, that are not sufficiently controlled by experimental data for the 'elementary' reactions in vacuum.Comment: 46 pages, including 15 eps figures, to be published in Phys. Rev.

    Carbon nanotubes for coherent spintronic devices

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    Carbon nanotubes bridge the molecular and crystalline quantum worlds, and their extraordinary electronic, mechanical and optical properties have attracted enormous attention from a broad scientific community. We review the basic principles of fabricating spin-electronic devices based on individual, electrically-gated carbon nanotubes, and present experimental efforts to understand their electronic and nuclear spin degrees of freedom, which in the future may enable quantum applications.Comment: 17 pages, 9 figures, submitted to Materials Toda

    Active Brownian Particles. From Individual to Collective Stochastic Dynamics

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    We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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